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, hax, 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, hax, 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, hax, 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 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 190 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 191SRST 192``-accel name[,prop=value[,...]]`` 193 This is used to enable an accelerator. Depending on the target 194 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 195 default, tcg is used. If there is more than one accelerator 196 specified, the next one is used if the previous one fails to 197 initialize. 198 199 ``igd-passthru=on|off`` 200 When Xen is in use, this option controls whether Intel 201 integrated graphics devices can be passed through to the guest 202 (default=off) 203 204 ``kernel-irqchip=on|off|split`` 205 Controls KVM in-kernel irqchip support. The default is full 206 acceleration of the interrupt controllers. On x86, split irqchip 207 reduces the kernel attack surface, at a performance cost for 208 non-MSI interrupts. Disabling the in-kernel irqchip completely 209 is not recommended except for debugging purposes. 210 211 ``kvm-shadow-mem=size`` 212 Defines the size of the KVM shadow MMU. 213 214 ``one-insn-per-tb=on|off`` 215 Makes the TCG accelerator put only one guest instruction into 216 each translation block. This slows down emulation a lot, but 217 can be useful in some situations, such as when trying to analyse 218 the logs produced by the ``-d`` option. 219 220 ``split-wx=on|off`` 221 Controls the use of split w^x mapping for the TCG code generation 222 buffer. Some operating systems require this to be enabled, and in 223 such a case this will default on. On other operating systems, this 224 will default off, but one may enable this for testing or debugging. 225 226 ``tb-size=n`` 227 Controls the size (in MiB) of the TCG translation block cache. 228 229 ``thread=single|multi`` 230 Controls number of TCG threads. When the TCG is multi-threaded 231 there will be one thread per vCPU therefore taking advantage of 232 additional host cores. The default is to enable multi-threading 233 where both the back-end and front-ends support it and no 234 incompatible TCG features have been enabled (e.g. 235 icount/replay). 236 237 ``dirty-ring-size=n`` 238 When the KVM accelerator is used, it controls the size of the per-vCPU 239 dirty page ring buffer (number of entries for each vCPU). It should 240 be a value that is power of two, and it should be 1024 or bigger (but 241 still less than the maximum value that the kernel supports). 4096 242 could be a good initial value if you have no idea which is the best. 243 Set this value to 0 to disable the feature. By default, this feature 244 is disabled (dirty-ring-size=0). When enabled, KVM will instead 245 record dirty pages in a bitmap. 246 247 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 248 Enables or disables notify VM exit support on x86 host and specify 249 the corresponding notify window to trigger the VM exit if enabled. 250 ``run`` option enables the feature. It does nothing and continue 251 if the exit happens. ``internal-error`` option enables the feature. 252 It raises a internal error. ``disable`` option doesn't enable the feature. 253 This feature can mitigate the CPU stuck issue due to event windows don't 254 open up for a specified of time (i.e. notify-window). 255 Default: notify-vmexit=run,notify-window=0. 256 257ERST 258 259DEF("smp", HAS_ARG, QEMU_OPTION_smp, 260 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 261 " set the number of initial CPUs to 'n' [default=1]\n" 262 " maxcpus= maximum number of total CPUs, including\n" 263 " offline CPUs for hotplug, etc\n" 264 " sockets= number of sockets on the machine board\n" 265 " dies= number of dies in one socket\n" 266 " clusters= number of clusters in one die\n" 267 " cores= number of cores in one cluster\n" 268 " threads= number of threads in one core\n" 269 "Note: Different machines may have different subsets of the CPU topology\n" 270 " parameters supported, so the actual meaning of the supported parameters\n" 271 " will vary accordingly. For example, for a machine type that supports a\n" 272 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 273 " sequentially mean as below:\n" 274 " sockets means the number of sockets on the machine board\n" 275 " cores means the number of cores in one socket\n" 276 " threads means the number of threads in one core\n" 277 " For a particular machine type board, an expected CPU topology hierarchy\n" 278 " can be defined through the supported sub-option. Unsupported parameters\n" 279 " can also be provided in addition to the sub-option, but their values\n" 280 " must be set as 1 in the purpose of correct parsing.\n", 281 QEMU_ARCH_ALL) 282SRST 283``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 284 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 285 the machine type board. On boards supporting CPU hotplug, the optional 286 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 287 added at runtime. When both parameters are omitted, the maximum number 288 of CPUs will be calculated from the provided topology members and the 289 initial CPU count will match the maximum number. When only one of them 290 is given then the omitted one will be set to its counterpart's value. 291 Both parameters may be specified, but the maximum number of CPUs must 292 be equal to or greater than the initial CPU count. Product of the 293 CPU topology hierarchy must be equal to the maximum number of CPUs. 294 Both parameters are subject to an upper limit that is determined by 295 the specific machine type chosen. 296 297 To control reporting of CPU topology information, values of the topology 298 parameters can be specified. Machines may only support a subset of the 299 parameters and different machines may have different subsets supported 300 which vary depending on capacity of the corresponding CPU targets. So 301 for a particular machine type board, an expected topology hierarchy can 302 be defined through the supported sub-option. Unsupported parameters can 303 also be provided in addition to the sub-option, but their values must be 304 set as 1 in the purpose of correct parsing. 305 306 Either the initial CPU count, or at least one of the topology parameters 307 must be specified. The specified parameters must be greater than zero, 308 explicit configuration like "cpus=0" is not allowed. Values for any 309 omitted parameters will be computed from those which are given. 310 311 For example, the following sub-option defines a CPU topology hierarchy 312 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 313 core) for a machine that only supports sockets/cores/threads. 314 Some members of the option can be omitted but their values will be 315 automatically computed: 316 317 :: 318 319 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 320 321 The following sub-option defines a CPU topology hierarchy (2 sockets 322 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 323 per core) for PC machines which support sockets/dies/cores/threads. 324 Some members of the option can be omitted but their values will be 325 automatically computed: 326 327 :: 328 329 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 330 331 The following sub-option defines a CPU topology hierarchy (2 sockets 332 totally on the machine, 2 clusters per socket, 2 cores per cluster, 333 2 threads per core) for ARM virt machines which support sockets/clusters 334 /cores/threads. Some members of the option can be omitted but their values 335 will be automatically computed: 336 337 :: 338 339 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 340 341 Historically preference was given to the coarsest topology parameters 342 when computing missing values (ie sockets preferred over cores, which 343 were preferred over threads), however, this behaviour is considered 344 liable to change. Prior to 6.2 the preference was sockets over cores 345 over threads. Since 6.2 the preference is cores over sockets over threads. 346 347 For example, the following option defines a machine board with 2 sockets 348 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 349 350 :: 351 352 -smp 2 353 354 Note: The cluster topology will only be generated in ACPI and exposed 355 to guest if it's explicitly specified in -smp. 356ERST 357 358DEF("numa", HAS_ARG, QEMU_OPTION_numa, 359 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 360 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 361 "-numa dist,src=source,dst=destination,val=distance\n" 362 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 363 "-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" 364 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 365 QEMU_ARCH_ALL) 366SRST 367``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 368 \ 369``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 370 \ 371``-numa dist,src=source,dst=destination,val=distance`` 372 \ 373``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 374 \ 375``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 376 \ 377``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 378 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 379 distance from a source node to a destination node. Set the ACPI 380 Heterogeneous Memory Attributes for the given nodes. 381 382 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 383 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 384 contiguous range of CPU indexes (or a single VCPU if lastcpu is 385 omitted). A non-contiguous set of VCPUs can be represented by 386 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 387 omitted on all nodes, VCPUs are automatically split between them. 388 389 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 390 NUMA node: 391 392 :: 393 394 -numa node,cpus=0-2,cpus=5 395 396 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 397 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 398 assign CPU objects to a node using topology layout properties of 399 CPU. The set of properties is machine specific, and depends on used 400 machine type/'\ ``smp``\ ' options. It could be queried with 401 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 402 property specifies node to which CPU object will be assigned, it's 403 required for node to be declared with '\ ``node``\ ' option before 404 it's used with '\ ``cpu``\ ' option. 405 406 For example: 407 408 :: 409 410 -M pc \ 411 -smp 1,sockets=2,maxcpus=2 \ 412 -numa node,nodeid=0 -numa node,nodeid=1 \ 413 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 414 415 '\ ``memdev``\ ' option assigns RAM from a given memory backend 416 device to a node. It is recommended to use '\ ``memdev``\ ' option 417 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 418 option provides better performance and more control over the 419 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 420 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 421 422 For compatibility reasons, legacy '\ ``mem``\ ' option is 423 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 424 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 425 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 426 option, and vice versa. 427 428 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 429 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 430 for '\ ``-numa node``\ ' without memory specified was removed. 431 432 '\ ``initiator``\ ' is an additional option that points to an 433 initiator NUMA node that has best performance (the lowest latency or 434 largest bandwidth) to this NUMA node. Note that this option can be 435 set only when the machine property 'hmat' is set to 'on'. 436 437 Following example creates a machine with 2 NUMA nodes, node 0 has 438 CPU. node 1 has only memory, and its initiator is node 0. Note that 439 because node 0 has CPU, by default the initiator of node 0 is itself 440 and must be itself. 441 442 :: 443 444 -machine hmat=on \ 445 -m 2G,slots=2,maxmem=4G \ 446 -object memory-backend-ram,size=1G,id=m0 \ 447 -object memory-backend-ram,size=1G,id=m1 \ 448 -numa node,nodeid=0,memdev=m0 \ 449 -numa node,nodeid=1,memdev=m1,initiator=0 \ 450 -smp 2,sockets=2,maxcpus=2 \ 451 -numa cpu,node-id=0,socket-id=0 \ 452 -numa cpu,node-id=0,socket-id=1 453 454 source and destination are NUMA node IDs. distance is the NUMA 455 distance from source to destination. The distance from a node to 456 itself is always 10. If any pair of nodes is given a distance, then 457 all pairs must be given distances. Although, when distances are only 458 given in one direction for each pair of nodes, then the distances in 459 the opposite directions are assumed to be the same. If, however, an 460 asymmetrical pair of distances is given for even one node pair, then 461 all node pairs must be provided distance values for both directions, 462 even when they are symmetrical. When a node is unreachable from 463 another node, set the pair's distance to 255. 464 465 Note that the -``numa`` option doesn't allocate any of the specified 466 resources, it just assigns existing resources to NUMA nodes. This 467 means that one still has to use the ``-m``, ``-smp`` options to 468 allocate RAM and VCPUs respectively. 469 470 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 471 Information between initiator and target NUMA nodes in ACPI 472 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 473 create memory requests, usually it has one or more processors. 474 Target NUMA node contains addressable memory. 475 476 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 477 the memory hierarchy of the target NUMA node: if hierarchy is 478 'memory', the structure represents the memory performance; if 479 hierarchy is 'first-level\|second-level\|third-level', this 480 structure represents aggregated performance of memory side caches 481 for each domain. type of 'data-type' is type of data represented by 482 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 483 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 484 the target memory; if 'hierarchy' is 485 'first-level\|second-level\|third-level', 'data-type' is 486 'access\|read\|write' hit latency or 'access\|read\|write' hit 487 bandwidth of the target memory side cache. 488 489 lat is latency value in nanoseconds. bw is bandwidth value, the 490 possible value and units are NUM[M\|G\|T], mean that the bandwidth 491 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 492 used suffix). Note that if latency or bandwidth value is 0, means 493 the corresponding latency or bandwidth information is not provided. 494 495 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 496 belongs. size is the size of memory side cache in bytes. level is 497 the cache level described in this structure, note that the cache 498 level 0 should not be used with '\ ``hmat-cache``\ ' option. 499 associativity is the cache associativity, the possible value is 500 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 501 is the write policy. line is the cache Line size in bytes. 502 503 For example, the following options describe 2 NUMA nodes. Node 0 has 504 2 cpus and a ram, node 1 has only a ram. The processors in node 0 505 access memory in node 0 with access-latency 5 nanoseconds, 506 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 507 memory in NUMA node 1 with access-latency 10 nanoseconds, 508 access-bandwidth is 100 MB/s. And for memory side cache information, 509 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 510 policy is write-back, the cache Line size is 8 bytes: 511 512 :: 513 514 -machine hmat=on \ 515 -m 2G \ 516 -object memory-backend-ram,size=1G,id=m0 \ 517 -object memory-backend-ram,size=1G,id=m1 \ 518 -smp 2,sockets=2,maxcpus=2 \ 519 -numa node,nodeid=0,memdev=m0 \ 520 -numa node,nodeid=1,memdev=m1,initiator=0 \ 521 -numa cpu,node-id=0,socket-id=0 \ 522 -numa cpu,node-id=0,socket-id=1 \ 523 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 524 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 525 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 526 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 527 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 528 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 529ERST 530 531DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 532 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 533 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 534SRST 535``-add-fd fd=fd,set=set[,opaque=opaque]`` 536 Add a file descriptor to an fd set. Valid options are: 537 538 ``fd=fd`` 539 This option defines the file descriptor of which a duplicate is 540 added to fd set. The file descriptor cannot be stdin, stdout, or 541 stderr. 542 543 ``set=set`` 544 This option defines the ID of the fd set to add the file 545 descriptor to. 546 547 ``opaque=opaque`` 548 This option defines a free-form string that can be used to 549 describe fd. 550 551 You can open an image using pre-opened file descriptors from an fd 552 set: 553 554 .. parsed-literal:: 555 556 |qemu_system| \\ 557 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 558 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 559 -drive file=/dev/fdset/2,index=0,media=disk 560ERST 561 562DEF("set", HAS_ARG, QEMU_OPTION_set, 563 "-set group.id.arg=value\n" 564 " set <arg> parameter for item <id> of type <group>\n" 565 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 566SRST 567``-set group.id.arg=value`` 568 Set parameter arg for item id of type group 569ERST 570 571DEF("global", HAS_ARG, QEMU_OPTION_global, 572 "-global driver.property=value\n" 573 "-global driver=driver,property=property,value=value\n" 574 " set a global default for a driver property\n", 575 QEMU_ARCH_ALL) 576SRST 577``-global driver.prop=value`` 578 \ 579``-global driver=driver,property=property,value=value`` 580 Set default value of driver's property prop to value, e.g.: 581 582 .. parsed-literal:: 583 584 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 585 586 In particular, you can use this to set driver properties for devices 587 which are created automatically by the machine model. To create a 588 device which is not created automatically and set properties on it, 589 use -``device``. 590 591 -global driver.prop=value is shorthand for -global 592 driver=driver,property=prop,value=value. The longhand syntax works 593 even when driver contains a dot. 594ERST 595 596DEF("boot", HAS_ARG, QEMU_OPTION_boot, 597 "-boot [order=drives][,once=drives][,menu=on|off]\n" 598 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 599 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 600 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 601 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 602 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 603 QEMU_ARCH_ALL) 604SRST 605``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 606 Specify boot order drives as a string of drive letters. Valid drive 607 letters depend on the target architecture. The x86 PC uses: a, b 608 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 609 (Etherboot from network adapter 1-4), hard disk boot is the default. 610 To apply a particular boot order only on the first startup, specify 611 it via ``once``. Note that the ``order`` or ``once`` parameter 612 should not be used together with the ``bootindex`` property of 613 devices, since the firmware implementations normally do not support 614 both at the same time. 615 616 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 617 as firmware/BIOS supports them. The default is non-interactive boot. 618 619 A splash picture could be passed to bios, enabling user to show it 620 as logo, when option splash=sp\_name is given and menu=on, If 621 firmware/BIOS supports them. Currently Seabios for X86 system 622 support it. limitation: The splash file could be a jpeg file or a 623 BMP file in 24 BPP format(true color). The resolution should be 624 supported by the SVGA mode, so the recommended is 320x240, 640x480, 625 800x640. 626 627 A timeout could be passed to bios, guest will pause for rb\_timeout 628 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 629 not reboot, qemu passes '-1' to bios by default. Currently Seabios 630 for X86 system support it. 631 632 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 633 it. This only effects when boot priority is changed by bootindex 634 options. The default is non-strict boot. 635 636 .. parsed-literal:: 637 638 # try to boot from network first, then from hard disk 639 |qemu_system_x86| -boot order=nc 640 # boot from CD-ROM first, switch back to default order after reboot 641 |qemu_system_x86| -boot once=d 642 # boot with a splash picture for 5 seconds. 643 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 644 645 Note: The legacy format '-boot drives' is still supported but its 646 use is discouraged as it may be removed from future versions. 647ERST 648 649DEF("m", HAS_ARG, QEMU_OPTION_m, 650 "-m [size=]megs[,slots=n,maxmem=size]\n" 651 " configure guest RAM\n" 652 " size: initial amount of guest memory\n" 653 " slots: number of hotplug slots (default: none)\n" 654 " maxmem: maximum amount of guest memory (default: none)\n" 655 "NOTE: Some architectures might enforce a specific granularity\n", 656 QEMU_ARCH_ALL) 657SRST 658``-m [size=]megs[,slots=n,maxmem=size]`` 659 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 660 Optionally, a suffix of "M" or "G" can be used to signify a value in 661 megabytes or gigabytes respectively. Optional pair slots, maxmem 662 could be used to set amount of hotpluggable memory slots and maximum 663 amount of memory. Note that maxmem must be aligned to the page size. 664 665 For example, the following command-line sets the guest startup RAM 666 size to 1GB, creates 3 slots to hotplug additional memory and sets 667 the maximum memory the guest can reach to 4GB: 668 669 .. parsed-literal:: 670 671 |qemu_system| -m 1G,slots=3,maxmem=4G 672 673 If slots and maxmem are not specified, memory hotplug won't be 674 enabled and the guest startup RAM will never increase. 675ERST 676 677DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 678 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 679SRST 680``-mem-path path`` 681 Allocate guest RAM from a temporarily created file in path. 682ERST 683 684DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 685 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 686 QEMU_ARCH_ALL) 687SRST 688``-mem-prealloc`` 689 Preallocate memory when using -mem-path. 690ERST 691 692DEF("k", HAS_ARG, QEMU_OPTION_k, 693 "-k language use keyboard layout (for example 'fr' for French)\n", 694 QEMU_ARCH_ALL) 695SRST 696``-k language`` 697 Use keyboard layout language (for example ``fr`` for French). This 698 option is only needed where it is not easy to get raw PC keycodes 699 (e.g. on Macs, with some X11 servers or with a VNC or curses 700 display). You don't normally need to use it on PC/Linux or 701 PC/Windows hosts. 702 703 The available layouts are: 704 705 :: 706 707 ar de-ch es fo fr-ca hu ja mk no pt-br sv 708 da en-gb et fr fr-ch is lt nl pl ru th 709 de en-us fi fr-be hr it lv nl-be pt sl tr 710 711 The default is ``en-us``. 712ERST 713 714 715HXCOMM Deprecated by -audiodev 716DEF("audio-help", 0, QEMU_OPTION_audio_help, 717 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 718 QEMU_ARCH_ALL) 719SRST 720``-audio-help`` 721 Will show the -audiodev equivalent of the currently specified 722 (deprecated) environment variables. 723ERST 724 725DEF("audio", HAS_ARG, QEMU_OPTION_audio, 726 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 727 " specifies the audio backend and device to use;\n" 728 " apart from 'model', options are the same as for -audiodev.\n" 729 " use '-audio model=help' to show possible devices.\n", 730 QEMU_ARCH_ALL) 731SRST 732``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 733 This option is a shortcut for configuring both the guest audio 734 hardware and the host audio backend in one go. 735 The driver option is the same as with the corresponding ``-audiodev`` option below. 736 The guest hardware model can be set with ``model=modelname``. 737 738 Use ``driver=help`` to list the available drivers, 739 and ``model=help`` to list the available device types. 740 741 The following two example do exactly the same, to show how ``-audio`` 742 can be used to shorten the command line length: 743 744 .. parsed-literal:: 745 746 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 747 |qemu_system| -audio pa,model=sb16 748ERST 749 750DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 751 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 752 " specifies the audio backend to use\n" 753 " Use ``-audiodev help`` to list the available drivers\n" 754 " id= identifier of the backend\n" 755 " timer-period= timer period in microseconds\n" 756 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 757 " in|out.fixed-settings= use fixed settings for host audio\n" 758 " in|out.frequency= frequency to use with fixed settings\n" 759 " in|out.channels= number of channels to use with fixed settings\n" 760 " in|out.format= sample format to use with fixed settings\n" 761 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 762 " in|out.voices= number of voices to use\n" 763 " in|out.buffer-length= length of buffer in microseconds\n" 764 "-audiodev none,id=id,[,prop[=value][,...]]\n" 765 " dummy driver that discards all output\n" 766#ifdef CONFIG_AUDIO_ALSA 767 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 768 " in|out.dev= name of the audio device to use\n" 769 " in|out.period-length= length of period in microseconds\n" 770 " in|out.try-poll= attempt to use poll mode\n" 771 " threshold= threshold (in microseconds) when playback starts\n" 772#endif 773#ifdef CONFIG_AUDIO_COREAUDIO 774 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 775 " in|out.buffer-count= number of buffers\n" 776#endif 777#ifdef CONFIG_AUDIO_DSOUND 778 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 779 " latency= add extra latency to playback in microseconds\n" 780#endif 781#ifdef CONFIG_AUDIO_OSS 782 "-audiodev oss,id=id[,prop[=value][,...]]\n" 783 " in|out.dev= path of the audio device to use\n" 784 " in|out.buffer-count= number of buffers\n" 785 " in|out.try-poll= attempt to use poll mode\n" 786 " try-mmap= try using memory mapped access\n" 787 " exclusive= open device in exclusive mode\n" 788 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 789#endif 790#ifdef CONFIG_AUDIO_PA 791 "-audiodev pa,id=id[,prop[=value][,...]]\n" 792 " server= PulseAudio server address\n" 793 " in|out.name= source/sink device name\n" 794 " in|out.latency= desired latency in microseconds\n" 795#endif 796#ifdef CONFIG_AUDIO_PIPEWIRE 797 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 798 " in|out.name= source/sink device name\n" 799 " in|out.stream-name= name of pipewire stream\n" 800 " in|out.latency= desired latency in microseconds\n" 801#endif 802#ifdef CONFIG_AUDIO_SDL 803 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 804 " in|out.buffer-count= number of buffers\n" 805#endif 806#ifdef CONFIG_AUDIO_SNDIO 807 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 808#endif 809#ifdef CONFIG_SPICE 810 "-audiodev spice,id=id[,prop[=value][,...]]\n" 811#endif 812#ifdef CONFIG_DBUS_DISPLAY 813 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 814#endif 815 "-audiodev wav,id=id[,prop[=value][,...]]\n" 816 " path= path of wav file to record\n", 817 QEMU_ARCH_ALL) 818SRST 819``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 820 Adds a new audio backend driver identified by id. There are global 821 and driver specific properties. Some values can be set differently 822 for input and output, they're marked with ``in|out.``. You can set 823 the input's property with ``in.prop`` and the output's property with 824 ``out.prop``. For example: 825 826 :: 827 828 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 829 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 830 831 NOTE: parameter validation is known to be incomplete, in many cases 832 specifying an invalid option causes QEMU to print an error message 833 and continue emulation without sound. 834 835 Valid global options are: 836 837 ``id=identifier`` 838 Identifies the audio backend. 839 840 ``timer-period=period`` 841 Sets the timer period used by the audio subsystem in 842 microseconds. Default is 10000 (10 ms). 843 844 ``in|out.mixing-engine=on|off`` 845 Use QEMU's mixing engine to mix all streams inside QEMU and 846 convert audio formats when not supported by the backend. When 847 off, fixed-settings must be off too. Note that disabling this 848 option means that the selected backend must support multiple 849 streams and the audio formats used by the virtual cards, 850 otherwise you'll get no sound. It's not recommended to disable 851 this option unless you want to use 5.1 or 7.1 audio, as mixing 852 engine only supports mono and stereo audio. Default is on. 853 854 ``in|out.fixed-settings=on|off`` 855 Use fixed settings for host audio. When off, it will change 856 based on how the guest opens the sound card. In this case you 857 must not specify frequency, channels or format. Default is on. 858 859 ``in|out.frequency=frequency`` 860 Specify the frequency to use when using fixed-settings. Default 861 is 44100Hz. 862 863 ``in|out.channels=channels`` 864 Specify the number of channels to use when using fixed-settings. 865 Default is 2 (stereo). 866 867 ``in|out.format=format`` 868 Specify the sample format to use when using fixed-settings. 869 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 870 ``u32``, ``f32``. Default is ``s16``. 871 872 ``in|out.voices=voices`` 873 Specify the number of voices to use. Default is 1. 874 875 ``in|out.buffer-length=usecs`` 876 Sets the size of the buffer in microseconds. 877 878``-audiodev none,id=id[,prop[=value][,...]]`` 879 Creates a dummy backend that discards all outputs. This backend has 880 no backend specific properties. 881 882``-audiodev alsa,id=id[,prop[=value][,...]]`` 883 Creates backend using the ALSA. This backend is only available on 884 Linux. 885 886 ALSA specific options are: 887 888 ``in|out.dev=device`` 889 Specify the ALSA device to use for input and/or output. Default 890 is ``default``. 891 892 ``in|out.period-length=usecs`` 893 Sets the period length in microseconds. 894 895 ``in|out.try-poll=on|off`` 896 Attempt to use poll mode with the device. Default is on. 897 898 ``threshold=threshold`` 899 Threshold (in microseconds) when playback starts. Default is 0. 900 901``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 902 Creates a backend using Apple's Core Audio. This backend is only 903 available on Mac OS and only supports playback. 904 905 Core Audio specific options are: 906 907 ``in|out.buffer-count=count`` 908 Sets the count of the buffers. 909 910``-audiodev dsound,id=id[,prop[=value][,...]]`` 911 Creates a backend using Microsoft's DirectSound. This backend is 912 only available on Windows and only supports playback. 913 914 DirectSound specific options are: 915 916 ``latency=usecs`` 917 Add extra usecs microseconds latency to playback. Default is 918 10000 (10 ms). 919 920``-audiodev oss,id=id[,prop[=value][,...]]`` 921 Creates a backend using OSS. This backend is available on most 922 Unix-like systems. 923 924 OSS specific options are: 925 926 ``in|out.dev=device`` 927 Specify the file name of the OSS device to use. Default is 928 ``/dev/dsp``. 929 930 ``in|out.buffer-count=count`` 931 Sets the count of the buffers. 932 933 ``in|out.try-poll=on|of`` 934 Attempt to use poll mode with the device. Default is on. 935 936 ``try-mmap=on|off`` 937 Try using memory mapped device access. Default is off. 938 939 ``exclusive=on|off`` 940 Open the device in exclusive mode (vmix won't work in this 941 case). Default is off. 942 943 ``dsp-policy=policy`` 944 Sets the timing policy (between 0 and 10, where smaller number 945 means smaller latency but higher CPU usage). Use -1 to use 946 buffer sizes specified by ``buffer`` and ``buffer-count``. This 947 option is ignored if you do not have OSS 4. Default is 5. 948 949``-audiodev pa,id=id[,prop[=value][,...]]`` 950 Creates a backend using PulseAudio. This backend is available on 951 most systems. 952 953 PulseAudio specific options are: 954 955 ``server=server`` 956 Sets the PulseAudio server to connect to. 957 958 ``in|out.name=sink`` 959 Use the specified source/sink for recording/playback. 960 961 ``in|out.latency=usecs`` 962 Desired latency in microseconds. The PulseAudio server will try 963 to honor this value but actual latencies may be lower or higher. 964 965``-audiodev pipewire,id=id[,prop[=value][,...]]`` 966 Creates a backend using Pipewire. This backend is available on 967 most systems. 968 969 Pipewire specific options are: 970 971 ``in|out.latency=usecs`` 972 Desired latency in microseconds. 973 974 ``in|out.name=sink`` 975 Use the specified source/sink for recording/playback. 976 977 ``in|out.stream-name`` 978 Specify the name of pipewire stream. 979 980``-audiodev sdl,id=id[,prop[=value][,...]]`` 981 Creates a backend using SDL. This backend is available on most 982 systems, but you should use your platform's native backend if 983 possible. 984 985 SDL specific options are: 986 987 ``in|out.buffer-count=count`` 988 Sets the count of the buffers. 989 990``-audiodev sndio,id=id[,prop[=value][,...]]`` 991 Creates a backend using SNDIO. This backend is available on 992 OpenBSD and most other Unix-like systems. 993 994 Sndio specific options are: 995 996 ``in|out.dev=device`` 997 Specify the sndio device to use for input and/or output. Default 998 is ``default``. 999 1000 ``in|out.latency=usecs`` 1001 Sets the desired period length in microseconds. 1002 1003``-audiodev spice,id=id[,prop[=value][,...]]`` 1004 Creates a backend that sends audio through SPICE. This backend 1005 requires ``-spice`` and automatically selected in that case, so 1006 usually you can ignore this option. This backend has no backend 1007 specific properties. 1008 1009``-audiodev wav,id=id[,prop[=value][,...]]`` 1010 Creates a backend that writes audio to a WAV file. 1011 1012 Backend specific options are: 1013 1014 ``path=path`` 1015 Write recorded audio into the specified file. Default is 1016 ``qemu.wav``. 1017ERST 1018 1019DEF("device", HAS_ARG, QEMU_OPTION_device, 1020 "-device driver[,prop[=value][,...]]\n" 1021 " add device (based on driver)\n" 1022 " prop=value,... sets driver properties\n" 1023 " use '-device help' to print all possible drivers\n" 1024 " use '-device driver,help' to print all possible properties\n", 1025 QEMU_ARCH_ALL) 1026SRST 1027``-device driver[,prop[=value][,...]]`` 1028 Add device driver. prop=value sets driver properties. Valid 1029 properties depend on the driver. To get help on possible drivers and 1030 properties, use ``-device help`` and ``-device driver,help``. 1031 1032 Some drivers are: 1033 1034``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1035 Add an IPMI BMC. This is a simulation of a hardware management 1036 interface processor that normally sits on a system. It provides a 1037 watchdog and the ability to reset and power control the system. You 1038 need to connect this to an IPMI interface to make it useful 1039 1040 The IPMI slave address to use for the BMC. The default is 0x20. This 1041 address is the BMC's address on the I2C network of management 1042 controllers. If you don't know what this means, it is safe to ignore 1043 it. 1044 1045 ``id=id`` 1046 The BMC id for interfaces to use this device. 1047 1048 ``slave_addr=val`` 1049 Define slave address to use for the BMC. The default is 0x20. 1050 1051 ``sdrfile=file`` 1052 file containing raw Sensor Data Records (SDR) data. The default 1053 is none. 1054 1055 ``fruareasize=val`` 1056 size of a Field Replaceable Unit (FRU) area. The default is 1057 1024. 1058 1059 ``frudatafile=file`` 1060 file containing raw Field Replaceable Unit (FRU) inventory data. 1061 The default is none. 1062 1063 ``guid=uuid`` 1064 value for the GUID for the BMC, in standard UUID format. If this 1065 is set, get "Get GUID" command to the BMC will return it. 1066 Otherwise "Get GUID" will return an error. 1067 1068``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1069 Add a connection to an external IPMI BMC simulator. Instead of 1070 locally emulating the BMC like the above item, instead connect to an 1071 external entity that provides the IPMI services. 1072 1073 A connection is made to an external BMC simulator. If you do this, 1074 it is strongly recommended that you use the "reconnect=" chardev 1075 option to reconnect to the simulator if the connection is lost. Note 1076 that if this is not used carefully, it can be a security issue, as 1077 the interface has the ability to send resets, NMIs, and power off 1078 the VM. It's best if QEMU makes a connection to an external 1079 simulator running on a secure port on localhost, so neither the 1080 simulator nor QEMU is exposed to any outside network. 1081 1082 See the "lanserv/README.vm" file in the OpenIPMI library for more 1083 details on the external interface. 1084 1085``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1086 Add a KCS IPMI interface on the ISA bus. This also adds a 1087 corresponding ACPI and SMBIOS entries, if appropriate. 1088 1089 ``bmc=id`` 1090 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1091 above. 1092 1093 ``ioport=val`` 1094 Define the I/O address of the interface. The default is 0xca0 1095 for KCS. 1096 1097 ``irq=val`` 1098 Define the interrupt to use. The default is 5. To disable 1099 interrupts, set this to 0. 1100 1101``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1102 Like the KCS interface, but defines a BT interface. The default port 1103 is 0xe4 and the default interrupt is 5. 1104 1105``-device pci-ipmi-kcs,bmc=id`` 1106 Add a KCS IPMI interface on the PCI bus. 1107 1108 ``bmc=id`` 1109 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1110 1111``-device pci-ipmi-bt,bmc=id`` 1112 Like the KCS interface, but defines a BT interface on the PCI bus. 1113 1114``-device intel-iommu[,option=...]`` 1115 This is only supported by ``-machine q35``, which will enable Intel VT-d 1116 emulation within the guest. It supports below options: 1117 1118 ``intremap=on|off`` (default: auto) 1119 This enables interrupt remapping feature. It's required to enable 1120 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1121 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1122 The default value is "auto", which will be decided by the mode of 1123 kernel-irqchip. 1124 1125 ``caching-mode=on|off`` (default: off) 1126 This enables caching mode for the VT-d emulated device. When 1127 caching-mode is enabled, each guest DMA buffer mapping will generate an 1128 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1129 a synchronous way. It is required for ``-device vfio-pci`` to work 1130 with the VT-d device, because host assigned devices requires to setup 1131 the DMA mapping on the host before guest DMA starts. 1132 1133 ``device-iotlb=on|off`` (default: off) 1134 This enables device-iotlb capability for the emulated VT-d device. So 1135 far virtio/vhost should be the only real user for this parameter, 1136 paired with ats=on configured for the device. 1137 1138 ``aw-bits=39|48`` (default: 39) 1139 This decides the address width of IOVA address space. The address 1140 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1141 4-level IOMMU page tables. 1142 1143 Please also refer to the wiki page for general scenarios of VT-d 1144 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1145 1146ERST 1147 1148DEF("name", HAS_ARG, QEMU_OPTION_name, 1149 "-name string1[,process=string2][,debug-threads=on|off]\n" 1150 " set the name of the guest\n" 1151 " string1 sets the window title and string2 the process name\n" 1152 " When debug-threads is enabled, individual threads are given a separate name\n" 1153 " NOTE: The thread names are for debugging and not a stable API.\n", 1154 QEMU_ARCH_ALL) 1155SRST 1156``-name name`` 1157 Sets the name of the guest. This name will be displayed in the SDL 1158 window caption. The name will also be used for the VNC server. Also 1159 optionally set the top visible process name in Linux. Naming of 1160 individual threads can also be enabled on Linux to aid debugging. 1161ERST 1162 1163DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1164 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1165 " specify machine UUID\n", QEMU_ARCH_ALL) 1166SRST 1167``-uuid uuid`` 1168 Set system UUID. 1169ERST 1170 1171DEFHEADING() 1172 1173DEFHEADING(Block device options:) 1174 1175SRST 1176The QEMU block device handling options have a long history and 1177have gone through several iterations as the feature set and complexity 1178of the block layer have grown. Many online guides to QEMU often 1179reference older and deprecated options, which can lead to confusion. 1180 1181The most explicit way to describe disks is to use a combination of 1182``-device`` to specify the hardware device and ``-blockdev`` to 1183describe the backend. The device defines what the guest sees and the 1184backend describes how QEMU handles the data. It is the only guaranteed 1185stable interface for describing block devices and as such is 1186recommended for management tools and scripting. 1187 1188The ``-drive`` option combines the device and backend into a single 1189command line option which is a more human friendly. There is however no 1190interface stability guarantee although some older board models still 1191need updating to work with the modern blockdev forms. 1192 1193Older options like ``-hda`` are essentially macros which expand into 1194``-drive`` options for various drive interfaces. The original forms 1195bake in a lot of assumptions from the days when QEMU was emulating a 1196legacy PC, they are not recommended for modern configurations. 1197 1198ERST 1199 1200DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1201 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1202DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1203SRST 1204``-fda file`` 1205 \ 1206``-fdb file`` 1207 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1208 the System Emulation Users Guide). 1209ERST 1210 1211DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1212 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1213DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1214DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1215 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1216DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1217SRST 1218``-hda file`` 1219 \ 1220``-hdb file`` 1221 \ 1222``-hdc file`` 1223 \ 1224``-hdd file`` 1225 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1226 chapter in the System Emulation Users Guide). 1227ERST 1228 1229DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1230 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1231 QEMU_ARCH_ALL) 1232SRST 1233``-cdrom file`` 1234 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1235 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1236 as filename. 1237ERST 1238 1239DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1240 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1241 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1242 " [,read-only=on|off][,auto-read-only=on|off]\n" 1243 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1244 " [,driver specific parameters...]\n" 1245 " configure a block backend\n", QEMU_ARCH_ALL) 1246SRST 1247``-blockdev option[,option[,option[,...]]]`` 1248 Define a new block driver node. Some of the options apply to all 1249 block drivers, other options are only accepted for a specific block 1250 driver. See below for a list of generic options and options for the 1251 most common block drivers. 1252 1253 Options that expect a reference to another node (e.g. ``file``) can 1254 be given in two ways. Either you specify the node name of an already 1255 existing node (file=node-name), or you define a new node inline, 1256 adding options for the referenced node after a dot 1257 (file.filename=path,file.aio=native). 1258 1259 A block driver node created with ``-blockdev`` can be used for a 1260 guest device by specifying its node name for the ``drive`` property 1261 in a ``-device`` argument that defines a block device. 1262 1263 ``Valid options for any block driver node:`` 1264 ``driver`` 1265 Specifies the block driver to use for the given node. 1266 1267 ``node-name`` 1268 This defines the name of the block driver node by which it 1269 will be referenced later. The name must be unique, i.e. it 1270 must not match the name of a different block driver node, or 1271 (if you use ``-drive`` as well) the ID of a drive. 1272 1273 If no node name is specified, it is automatically generated. 1274 The generated node name is not intended to be predictable 1275 and changes between QEMU invocations. For the top level, an 1276 explicit node name must be specified. 1277 1278 ``read-only`` 1279 Open the node read-only. Guest write attempts will fail. 1280 1281 Note that some block drivers support only read-only access, 1282 either generally or in certain configurations. In this case, 1283 the default value ``read-only=off`` does not work and the 1284 option must be specified explicitly. 1285 1286 ``auto-read-only`` 1287 If ``auto-read-only=on`` is set, QEMU may fall back to 1288 read-only usage even when ``read-only=off`` is requested, or 1289 even switch between modes as needed, e.g. depending on 1290 whether the image file is writable or whether a writing user 1291 is attached to the node. 1292 1293 ``force-share`` 1294 Override the image locking system of QEMU by forcing the 1295 node to utilize weaker shared access for permissions where 1296 it would normally request exclusive access. When there is 1297 the potential for multiple instances to have the same file 1298 open (whether this invocation of QEMU is the first or the 1299 second instance), both instances must permit shared access 1300 for the second instance to succeed at opening the file. 1301 1302 Enabling ``force-share=on`` requires ``read-only=on``. 1303 1304 ``cache.direct`` 1305 The host page cache can be avoided with ``cache.direct=on``. 1306 This will attempt to do disk IO directly to the guest's 1307 memory. QEMU may still perform an internal copy of the data. 1308 1309 ``cache.no-flush`` 1310 In case you don't care about data integrity over host 1311 failures, you can use ``cache.no-flush=on``. This option 1312 tells QEMU that it never needs to write any data to the disk 1313 but can instead keep things in cache. If anything goes 1314 wrong, like your host losing power, the disk storage getting 1315 disconnected accidentally, etc. your image will most 1316 probably be rendered unusable. 1317 1318 ``discard=discard`` 1319 discard is one of "ignore" (or "off") or "unmap" (or "on") 1320 and controls whether ``discard`` (also known as ``trim`` or 1321 ``unmap``) requests are ignored or passed to the filesystem. 1322 Some machine types may not support discard requests. 1323 1324 ``detect-zeroes=detect-zeroes`` 1325 detect-zeroes is "off", "on" or "unmap" and enables the 1326 automatic conversion of plain zero writes by the OS to 1327 driver specific optimized zero write commands. You may even 1328 choose "unmap" if discard is set to "unmap" to allow a zero 1329 write to be converted to an ``unmap`` operation. 1330 1331 ``Driver-specific options for file`` 1332 This is the protocol-level block driver for accessing regular 1333 files. 1334 1335 ``filename`` 1336 The path to the image file in the local filesystem 1337 1338 ``aio`` 1339 Specifies the AIO backend (threads/native/io_uring, 1340 default: threads) 1341 1342 ``locking`` 1343 Specifies whether the image file is protected with Linux OFD 1344 / POSIX locks. The default is to use the Linux Open File 1345 Descriptor API if available, otherwise no lock is applied. 1346 (auto/on/off, default: auto) 1347 1348 Example: 1349 1350 :: 1351 1352 -blockdev driver=file,node-name=disk,filename=disk.img 1353 1354 ``Driver-specific options for raw`` 1355 This is the image format block driver for raw images. It is 1356 usually stacked on top of a protocol level block driver such as 1357 ``file``. 1358 1359 ``file`` 1360 Reference to or definition of the data source block driver 1361 node (e.g. a ``file`` driver node) 1362 1363 Example 1: 1364 1365 :: 1366 1367 -blockdev driver=file,node-name=disk_file,filename=disk.img 1368 -blockdev driver=raw,node-name=disk,file=disk_file 1369 1370 Example 2: 1371 1372 :: 1373 1374 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1375 1376 ``Driver-specific options for qcow2`` 1377 This is the image format block driver for qcow2 images. It is 1378 usually stacked on top of a protocol level block driver such as 1379 ``file``. 1380 1381 ``file`` 1382 Reference to or definition of the data source block driver 1383 node (e.g. a ``file`` driver node) 1384 1385 ``backing`` 1386 Reference to or definition of the backing file block device 1387 (default is taken from the image file). It is allowed to 1388 pass ``null`` here in order to disable the default backing 1389 file. 1390 1391 ``lazy-refcounts`` 1392 Whether to enable the lazy refcounts feature (on/off; 1393 default is taken from the image file) 1394 1395 ``cache-size`` 1396 The maximum total size of the L2 table and refcount block 1397 caches in bytes (default: the sum of l2-cache-size and 1398 refcount-cache-size) 1399 1400 ``l2-cache-size`` 1401 The maximum size of the L2 table cache in bytes (default: if 1402 cache-size is not specified - 32M on Linux platforms, and 8M 1403 on non-Linux platforms; otherwise, as large as possible 1404 within the cache-size, while permitting the requested or the 1405 minimal refcount cache size) 1406 1407 ``refcount-cache-size`` 1408 The maximum size of the refcount block cache in bytes 1409 (default: 4 times the cluster size; or if cache-size is 1410 specified, the part of it which is not used for the L2 1411 cache) 1412 1413 ``cache-clean-interval`` 1414 Clean unused entries in the L2 and refcount caches. The 1415 interval is in seconds. The default value is 600 on 1416 supporting platforms, and 0 on other platforms. Setting it 1417 to 0 disables this feature. 1418 1419 ``pass-discard-request`` 1420 Whether discard requests to the qcow2 device should be 1421 forwarded to the data source (on/off; default: on if 1422 discard=unmap is specified, off otherwise) 1423 1424 ``pass-discard-snapshot`` 1425 Whether discard requests for the data source should be 1426 issued when a snapshot operation (e.g. deleting a snapshot) 1427 frees clusters in the qcow2 file (on/off; default: on) 1428 1429 ``pass-discard-other`` 1430 Whether discard requests for the data source should be 1431 issued on other occasions where a cluster gets freed 1432 (on/off; default: off) 1433 1434 ``discard-no-unref`` 1435 When enabled, discards from the guest will not cause cluster 1436 allocations to be relinquished. This prevents qcow2 fragmentation 1437 that would be caused by such discards. Besides potential 1438 performance degradation, such fragmentation can lead to increased 1439 allocation of clusters past the end of the image file, 1440 resulting in image files whose file length can grow much larger 1441 than their guest disk size would suggest. 1442 If image file length is of concern (e.g. when storing qcow2 1443 images directly on block devices), you should consider enabling 1444 this option. 1445 1446 ``overlap-check`` 1447 Which overlap checks to perform for writes to the image 1448 (none/constant/cached/all; default: cached). For details or 1449 finer granularity control refer to the QAPI documentation of 1450 ``blockdev-add``. 1451 1452 Example 1: 1453 1454 :: 1455 1456 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1457 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1458 1459 Example 2: 1460 1461 :: 1462 1463 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1464 1465 ``Driver-specific options for other drivers`` 1466 Please refer to the QAPI documentation of the ``blockdev-add`` 1467 QMP command. 1468ERST 1469 1470DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1471 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1472 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1473 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1474 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1475 " [,aio=threads|native|io_uring]\n" 1476 " [,readonly=on|off][,copy-on-read=on|off]\n" 1477 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1478 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1479 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1480 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1481 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1482 " [[,iops_size=is]]\n" 1483 " [[,group=g]]\n" 1484 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1485SRST 1486``-drive option[,option[,option[,...]]]`` 1487 Define a new drive. This includes creating a block driver node (the 1488 backend) as well as a guest device, and is mostly a shortcut for 1489 defining the corresponding ``-blockdev`` and ``-device`` options. 1490 1491 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1492 In addition, it knows the following options: 1493 1494 ``file=file`` 1495 This option defines which disk image (see the :ref:`disk images` 1496 chapter in the System Emulation Users Guide) to use with this drive. 1497 If the filename contains comma, you must double it (for instance, 1498 "file=my,,file" to use file "my,file"). 1499 1500 Special files such as iSCSI devices can be specified using 1501 protocol specific URLs. See the section for "Device URL Syntax" 1502 for more information. 1503 1504 ``if=interface`` 1505 This option defines on which type on interface the drive is 1506 connected. Available types are: ide, scsi, sd, mtd, floppy, 1507 pflash, virtio, none. 1508 1509 ``bus=bus,unit=unit`` 1510 These options define where is connected the drive by defining 1511 the bus number and the unit id. 1512 1513 ``index=index`` 1514 This option defines where the drive is connected by using an 1515 index in the list of available connectors of a given interface 1516 type. 1517 1518 ``media=media`` 1519 This option defines the type of the media: disk or cdrom. 1520 1521 ``snapshot=snapshot`` 1522 snapshot is "on" or "off" and controls snapshot mode for the 1523 given drive (see ``-snapshot``). 1524 1525 ``cache=cache`` 1526 cache is "none", "writeback", "unsafe", "directsync" or 1527 "writethrough" and controls how the host cache is used to access 1528 block data. This is a shortcut that sets the ``cache.direct`` 1529 and ``cache.no-flush`` options (as in ``-blockdev``), and 1530 additionally ``cache.writeback``, which provides a default for 1531 the ``write-cache`` option of block guest devices (as in 1532 ``-device``). The modes correspond to the following settings: 1533 1534 ============= =============== ============ ============== 1535 \ cache.writeback cache.direct cache.no-flush 1536 ============= =============== ============ ============== 1537 writeback on off off 1538 none on on off 1539 writethrough off off off 1540 directsync off on off 1541 unsafe on off on 1542 ============= =============== ============ ============== 1543 1544 The default mode is ``cache=writeback``. 1545 1546 ``aio=aio`` 1547 aio is "threads", "native", or "io_uring" and selects between pthread 1548 based disk I/O, native Linux AIO, or Linux io_uring API. 1549 1550 ``format=format`` 1551 Specify which disk format will be used rather than detecting the 1552 format. Can be used to specify format=raw to avoid interpreting 1553 an untrusted format header. 1554 1555 ``werror=action,rerror=action`` 1556 Specify which action to take on write and read errors. Valid 1557 actions are: "ignore" (ignore the error and try to continue), 1558 "stop" (pause QEMU), "report" (report the error to the guest), 1559 "enospc" (pause QEMU only if the host disk is full; report the 1560 error to the guest otherwise). The default setting is 1561 ``werror=enospc`` and ``rerror=report``. 1562 1563 ``copy-on-read=copy-on-read`` 1564 copy-on-read is "on" or "off" and enables whether to copy read 1565 backing file sectors into the image file. 1566 1567 ``bps=b,bps_rd=r,bps_wr=w`` 1568 Specify bandwidth throttling limits in bytes per second, either 1569 for all request types or for reads or writes only. Small values 1570 can lead to timeouts or hangs inside the guest. A safe minimum 1571 for disks is 2 MB/s. 1572 1573 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1574 Specify bursts in bytes per second, either for all request types 1575 or for reads or writes only. Bursts allow the guest I/O to spike 1576 above the limit temporarily. 1577 1578 ``iops=i,iops_rd=r,iops_wr=w`` 1579 Specify request rate limits in requests per second, either for 1580 all request types or for reads or writes only. 1581 1582 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1583 Specify bursts in requests per second, either for all request 1584 types or for reads or writes only. Bursts allow the guest I/O to 1585 spike above the limit temporarily. 1586 1587 ``iops_size=is`` 1588 Let every is bytes of a request count as a new request for iops 1589 throttling purposes. Use this option to prevent guests from 1590 circumventing iops limits by sending fewer but larger requests. 1591 1592 ``group=g`` 1593 Join a throttling quota group with given name g. All drives that 1594 are members of the same group are accounted for together. Use 1595 this option to prevent guests from circumventing throttling 1596 limits by using many small disks instead of a single larger 1597 disk. 1598 1599 By default, the ``cache.writeback=on`` mode is used. It will report 1600 data writes as completed as soon as the data is present in the host 1601 page cache. This is safe as long as your guest OS makes sure to 1602 correctly flush disk caches where needed. If your guest OS does not 1603 handle volatile disk write caches correctly and your host crashes or 1604 loses power, then the guest may experience data corruption. 1605 1606 For such guests, you should consider using ``cache.writeback=off``. 1607 This means that the host page cache will be used to read and write 1608 data, but write notification will be sent to the guest only after 1609 QEMU has made sure to flush each write to the disk. Be aware that 1610 this has a major impact on performance. 1611 1612 When using the ``-snapshot`` option, unsafe caching is always used. 1613 1614 Copy-on-read avoids accessing the same backing file sectors 1615 repeatedly and is useful when the backing file is over a slow 1616 network. By default copy-on-read is off. 1617 1618 Instead of ``-cdrom`` you can use: 1619 1620 .. parsed-literal:: 1621 1622 |qemu_system| -drive file=file,index=2,media=cdrom 1623 1624 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1625 1626 .. parsed-literal:: 1627 1628 |qemu_system| -drive file=file,index=0,media=disk 1629 |qemu_system| -drive file=file,index=1,media=disk 1630 |qemu_system| -drive file=file,index=2,media=disk 1631 |qemu_system| -drive file=file,index=3,media=disk 1632 1633 You can open an image using pre-opened file descriptors from an fd 1634 set: 1635 1636 .. parsed-literal:: 1637 1638 |qemu_system| \\ 1639 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1640 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1641 -drive file=/dev/fdset/2,index=0,media=disk 1642 1643 You can connect a CDROM to the slave of ide0: 1644 1645 .. parsed-literal:: 1646 1647 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1648 1649 If you don't specify the "file=" argument, you define an empty 1650 drive: 1651 1652 .. parsed-literal:: 1653 1654 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1655 1656 Instead of ``-fda``, ``-fdb``, you can use: 1657 1658 .. parsed-literal:: 1659 1660 |qemu_system_x86| -drive file=file,index=0,if=floppy 1661 |qemu_system_x86| -drive file=file,index=1,if=floppy 1662 1663 By default, interface is "ide" and index is automatically 1664 incremented: 1665 1666 .. parsed-literal:: 1667 1668 |qemu_system_x86| -drive file=a -drive file=b 1669 1670 is interpreted like: 1671 1672 .. parsed-literal:: 1673 1674 |qemu_system_x86| -hda a -hdb b 1675ERST 1676 1677DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1678 "-mtdblock file use 'file' as on-board Flash memory image\n", 1679 QEMU_ARCH_ALL) 1680SRST 1681``-mtdblock file`` 1682 Use file as on-board Flash memory image. 1683ERST 1684 1685DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1686 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1687SRST 1688``-sd file`` 1689 Use file as SecureDigital card image. 1690ERST 1691 1692DEF("snapshot", 0, QEMU_OPTION_snapshot, 1693 "-snapshot write to temporary files instead of disk image files\n", 1694 QEMU_ARCH_ALL) 1695SRST 1696``-snapshot`` 1697 Write to temporary files instead of disk image files. In this case, 1698 the raw disk image you use is not written back. You can however 1699 force the write back by pressing C-a s (see the :ref:`disk images` 1700 chapter in the System Emulation Users Guide). 1701 1702 .. warning:: 1703 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1704 to manually create snapshot images to attach to your blockdev). 1705 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1706 can use the 'snapshot' property on your drive declarations 1707 instead of this global option. 1708 1709ERST 1710 1711DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1712 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1713 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1714 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1715 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1716 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1717 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1718 " [[,throttling.iops-size=is]]\n" 1719 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1720 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1721 "-fsdev synth,id=id\n", 1722 QEMU_ARCH_ALL) 1723 1724SRST 1725``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1726 \ 1727``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1728 \ 1729``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1730 \ 1731``-fsdev synth,id=id[,readonly=on]`` 1732 Define a new file system device. Valid options are: 1733 1734 ``local`` 1735 Accesses to the filesystem are done by QEMU. 1736 1737 ``proxy`` 1738 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1739 1740 ``synth`` 1741 Synthetic filesystem, only used by QTests. 1742 1743 ``id=id`` 1744 Specifies identifier for this device. 1745 1746 ``path=path`` 1747 Specifies the export path for the file system device. Files 1748 under this path will be available to the 9p client on the guest. 1749 1750 ``security_model=security_model`` 1751 Specifies the security model to be used for this export path. 1752 Supported security models are "passthrough", "mapped-xattr", 1753 "mapped-file" and "none". In "passthrough" security model, files 1754 are stored using the same credentials as they are created on the 1755 guest. This requires QEMU to run as root. In "mapped-xattr" 1756 security model, some of the file attributes like uid, gid, mode 1757 bits and link target are stored as file attributes. For 1758 "mapped-file" these attributes are stored in the hidden 1759 .virtfs\_metadata directory. Directories exported by this 1760 security model cannot interact with other unix tools. "none" 1761 security model is same as passthrough except the sever won't 1762 report failures if it fails to set file attributes like 1763 ownership. Security model is mandatory only for local fsdriver. 1764 Other fsdrivers (like proxy) don't take security model as a 1765 parameter. 1766 1767 ``writeout=writeout`` 1768 This is an optional argument. The only supported value is 1769 "immediate". This means that host page cache will be used to 1770 read and write data but write notification will be sent to the 1771 guest only when the data has been reported as written by the 1772 storage subsystem. 1773 1774 ``readonly=on`` 1775 Enables exporting 9p share as a readonly mount for guests. By 1776 default read-write access is given. 1777 1778 ``socket=socket`` 1779 Enables proxy filesystem driver to use passed socket file for 1780 communicating with virtfs-proxy-helper(1). 1781 1782 ``sock_fd=sock_fd`` 1783 Enables proxy filesystem driver to use passed socket descriptor 1784 for communicating with virtfs-proxy-helper(1). Usually a helper 1785 like libvirt will create socketpair and pass one of the fds as 1786 sock\_fd. 1787 1788 ``fmode=fmode`` 1789 Specifies the default mode for newly created files on the host. 1790 Works only with security models "mapped-xattr" and 1791 "mapped-file". 1792 1793 ``dmode=dmode`` 1794 Specifies the default mode for newly created directories on the 1795 host. Works only with security models "mapped-xattr" and 1796 "mapped-file". 1797 1798 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1799 Specify bandwidth throttling limits in bytes per second, either 1800 for all request types or for reads or writes only. 1801 1802 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1803 Specify bursts in bytes per second, either for all request types 1804 or for reads or writes only. Bursts allow the guest I/O to spike 1805 above the limit temporarily. 1806 1807 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1808 Specify request rate limits in requests per second, either for 1809 all request types or for reads or writes only. 1810 1811 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1812 Specify bursts in requests per second, either for all request 1813 types or for reads or writes only. Bursts allow the guest I/O to 1814 spike above the limit temporarily. 1815 1816 ``throttling.iops-size=is`` 1817 Let every is bytes of a request count as a new request for iops 1818 throttling purposes. 1819 1820 -fsdev option is used along with -device driver "virtio-9p-...". 1821 1822``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1823 Options for virtio-9p-... driver are: 1824 1825 ``type`` 1826 Specifies the variant to be used. Supported values are "pci", 1827 "ccw" or "device", depending on the machine type. 1828 1829 ``fsdev=id`` 1830 Specifies the id value specified along with -fsdev option. 1831 1832 ``mount_tag=mount_tag`` 1833 Specifies the tag name to be used by the guest to mount this 1834 export point. 1835ERST 1836 1837DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1838 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1839 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1840 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1841 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1842 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1843 QEMU_ARCH_ALL) 1844 1845SRST 1846``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1847 \ 1848``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1849 \ 1850``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1851 \ 1852``-virtfs synth,mount_tag=mount_tag`` 1853 Define a new virtual filesystem device and expose it to the guest using 1854 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1855 directory on host is made directly accessible by guest as a pass-through 1856 file system by using the 9P network protocol for communication between 1857 host and guests, if desired even accessible, shared by several guests 1858 simultaneously. 1859 1860 Note that ``-virtfs`` is actually just a convenience shortcut for its 1861 generalized form ``-fsdev -device virtio-9p-pci``. 1862 1863 The general form of pass-through file system options are: 1864 1865 ``local`` 1866 Accesses to the filesystem are done by QEMU. 1867 1868 ``proxy`` 1869 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1870 1871 ``synth`` 1872 Synthetic filesystem, only used by QTests. 1873 1874 ``id=id`` 1875 Specifies identifier for the filesystem device 1876 1877 ``path=path`` 1878 Specifies the export path for the file system device. Files 1879 under this path will be available to the 9p client on the guest. 1880 1881 ``security_model=security_model`` 1882 Specifies the security model to be used for this export path. 1883 Supported security models are "passthrough", "mapped-xattr", 1884 "mapped-file" and "none". In "passthrough" security model, files 1885 are stored using the same credentials as they are created on the 1886 guest. This requires QEMU to run as root. In "mapped-xattr" 1887 security model, some of the file attributes like uid, gid, mode 1888 bits and link target are stored as file attributes. For 1889 "mapped-file" these attributes are stored in the hidden 1890 .virtfs\_metadata directory. Directories exported by this 1891 security model cannot interact with other unix tools. "none" 1892 security model is same as passthrough except the sever won't 1893 report failures if it fails to set file attributes like 1894 ownership. Security model is mandatory only for local fsdriver. 1895 Other fsdrivers (like proxy) don't take security model as a 1896 parameter. 1897 1898 ``writeout=writeout`` 1899 This is an optional argument. The only supported value is 1900 "immediate". This means that host page cache will be used to 1901 read and write data but write notification will be sent to the 1902 guest only when the data has been reported as written by the 1903 storage subsystem. 1904 1905 ``readonly=on`` 1906 Enables exporting 9p share as a readonly mount for guests. By 1907 default read-write access is given. 1908 1909 ``socket=socket`` 1910 Enables proxy filesystem driver to use passed socket file for 1911 communicating with virtfs-proxy-helper(1). Usually a helper like 1912 libvirt will create socketpair and pass one of the fds as 1913 sock\_fd. 1914 1915 ``sock_fd`` 1916 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1917 socket descriptor for interfacing with virtfs-proxy-helper(1). 1918 1919 ``fmode=fmode`` 1920 Specifies the default mode for newly created files on the host. 1921 Works only with security models "mapped-xattr" and 1922 "mapped-file". 1923 1924 ``dmode=dmode`` 1925 Specifies the default mode for newly created directories on the 1926 host. Works only with security models "mapped-xattr" and 1927 "mapped-file". 1928 1929 ``mount_tag=mount_tag`` 1930 Specifies the tag name to be used by the guest to mount this 1931 export point. 1932 1933 ``multidevs=multidevs`` 1934 Specifies how to deal with multiple devices being shared with a 1935 9p export. Supported behaviours are either "remap", "forbid" or 1936 "warn". The latter is the default behaviour on which virtfs 9p 1937 expects only one device to be shared with the same export, and 1938 if more than one device is shared and accessed via the same 9p 1939 export then only a warning message is logged (once) by qemu on 1940 host side. In order to avoid file ID collisions on guest you 1941 should either create a separate virtfs export for each device to 1942 be shared with guests (recommended way) or you might use "remap" 1943 instead which allows you to share multiple devices with only one 1944 export instead, which is achieved by remapping the original 1945 inode numbers from host to guest in a way that would prevent 1946 such collisions. Remapping inodes in such use cases is required 1947 because the original device IDs from host are never passed and 1948 exposed on guest. Instead all files of an export shared with 1949 virtfs always share the same device id on guest. So two files 1950 with identical inode numbers but from actually different devices 1951 on host would otherwise cause a file ID collision and hence 1952 potential misbehaviours on guest. "forbid" on the other hand 1953 assumes like "warn" that only one device is shared by the same 1954 export, however it will not only log a warning message but also 1955 deny access to additional devices on guest. Note though that 1956 "forbid" does currently not block all possible file access 1957 operations (e.g. readdir() would still return entries from other 1958 devices). 1959ERST 1960 1961DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1962 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1963 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1964 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1965 " [,timeout=timeout]\n" 1966 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1967 1968SRST 1969``-iscsi`` 1970 Configure iSCSI session parameters. 1971ERST 1972 1973DEFHEADING() 1974 1975DEFHEADING(USB convenience options:) 1976 1977DEF("usb", 0, QEMU_OPTION_usb, 1978 "-usb enable on-board USB host controller (if not enabled by default)\n", 1979 QEMU_ARCH_ALL) 1980SRST 1981``-usb`` 1982 Enable USB emulation on machine types with an on-board USB host 1983 controller (if not enabled by default). Note that on-board USB host 1984 controllers may not support USB 3.0. In this case 1985 ``-device qemu-xhci`` can be used instead on machines with PCI. 1986ERST 1987 1988DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1989 "-usbdevice name add the host or guest USB device 'name'\n", 1990 QEMU_ARCH_ALL) 1991SRST 1992``-usbdevice devname`` 1993 Add the USB device devname, and enable an on-board USB controller 1994 if possible and necessary (just like it can be done via 1995 ``-machine usb=on``). Note that this option is mainly intended for 1996 the user's convenience only. More fine-grained control can be 1997 achieved by selecting a USB host controller (if necessary) and the 1998 desired USB device via the ``-device`` option instead. For example, 1999 instead of using ``-usbdevice mouse`` it is possible to use 2000 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2001 to a USB 3.0 controller instead (at least on machines that support 2002 PCI and do not have an USB controller enabled by default yet). 2003 For more details, see the chapter about 2004 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2005 Possible devices for devname are: 2006 2007 ``braille`` 2008 Braille device. This will use BrlAPI to display the braille 2009 output on a real or fake device (i.e. it also creates a 2010 corresponding ``braille`` chardev automatically beside the 2011 ``usb-braille`` USB device). 2012 2013 ``keyboard`` 2014 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2015 2016 ``mouse`` 2017 Virtual Mouse. This will override the PS/2 mouse emulation when 2018 activated. 2019 2020 ``tablet`` 2021 Pointer device that uses absolute coordinates (like a 2022 touchscreen). This means QEMU is able to report the mouse 2023 position without having to grab the mouse. Also overrides the 2024 PS/2 mouse emulation when activated. 2025 2026 ``wacom-tablet`` 2027 Wacom PenPartner USB tablet. 2028 2029 2030ERST 2031 2032DEFHEADING() 2033 2034DEFHEADING(Display options:) 2035 2036DEF("display", HAS_ARG, QEMU_OPTION_display, 2037#if defined(CONFIG_SPICE) 2038 "-display spice-app[,gl=on|off]\n" 2039#endif 2040#if defined(CONFIG_SDL) 2041 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2042 " [,window-close=on|off]\n" 2043#endif 2044#if defined(CONFIG_GTK) 2045 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2046 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2047 " [,show-menubar=on|off]\n" 2048#endif 2049#if defined(CONFIG_VNC) 2050 "-display vnc=<display>[,<optargs>]\n" 2051#endif 2052#if defined(CONFIG_CURSES) 2053 "-display curses[,charset=<encoding>]\n" 2054#endif 2055#if defined(CONFIG_COCOA) 2056 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2057#endif 2058#if defined(CONFIG_OPENGL) 2059 "-display egl-headless[,rendernode=<file>]\n" 2060#endif 2061#if defined(CONFIG_DBUS_DISPLAY) 2062 "-display dbus[,addr=<dbusaddr>]\n" 2063 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2064#endif 2065#if defined(CONFIG_COCOA) 2066 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 2067#endif 2068 "-display none\n" 2069 " select display backend type\n" 2070 " The default display is equivalent to\n " 2071#if defined(CONFIG_GTK) 2072 "\"-display gtk\"\n" 2073#elif defined(CONFIG_SDL) 2074 "\"-display sdl\"\n" 2075#elif defined(CONFIG_COCOA) 2076 "\"-display cocoa\"\n" 2077#elif defined(CONFIG_VNC) 2078 "\"-vnc localhost:0,to=99,id=default\"\n" 2079#else 2080 "\"-display none\"\n" 2081#endif 2082 , QEMU_ARCH_ALL) 2083SRST 2084``-display type`` 2085 Select type of display to use. Use ``-display help`` to list the available 2086 display types. Valid values for type are 2087 2088 ``spice-app[,gl=on|off]`` 2089 Start QEMU as a Spice server and launch the default Spice client 2090 application. The Spice server will redirect the serial consoles 2091 and QEMU monitors. (Since 4.0) 2092 2093 ``dbus`` 2094 Export the display over D-Bus interfaces. (Since 7.0) 2095 2096 The connection is registered with the "org.qemu" name (and queued when 2097 already owned). 2098 2099 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2100 2101 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2102 2103 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2104 will share framebuffers with DMABUF file descriptors). 2105 2106 ``sdl`` 2107 Display video output via SDL (usually in a separate graphics 2108 window; see the SDL documentation for other possibilities). 2109 Valid parameters are: 2110 2111 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2112 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2113 either ``lshift-lctrl-lalt`` or ``rctrl``. 2114 2115 ``gl=on|off|core|es`` : Use OpenGL for displaying 2116 2117 ``show-cursor=on|off`` : Force showing the mouse cursor 2118 2119 ``window-close=on|off`` : Allow to quit qemu with window close button 2120 2121 ``gtk`` 2122 Display video output in a GTK window. This interface provides 2123 drop-down menus and other UI elements to configure and control 2124 the VM during runtime. Valid parameters are: 2125 2126 ``full-screen=on|off`` : Start in fullscreen mode 2127 2128 ``gl=on|off`` : Use OpenGL for displaying 2129 2130 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2131 2132 ``show-tabs=on|off`` : Display the tab bar for switching between the 2133 various graphical interfaces (e.g. VGA and 2134 virtual console character devices) by default. 2135 2136 ``show-cursor=on|off`` : Force showing the mouse cursor 2137 2138 ``window-close=on|off`` : Allow to quit qemu with window close button 2139 2140 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2141 2142 ``curses[,charset=<encoding>]`` 2143 Display video output via curses. For graphics device models 2144 which support a text mode, QEMU can display this output using a 2145 curses/ncurses interface. Nothing is displayed when the graphics 2146 device is in graphical mode or if the graphics device does not 2147 support a text mode. Generally only the VGA device models 2148 support text mode. The font charset used by the guest can be 2149 specified with the ``charset`` option, for example 2150 ``charset=CP850`` for IBM CP850 encoding. The default is 2151 ``CP437``. 2152 2153 ``cocoa`` 2154 Display video output in a Cocoa window. Mac only. This interface 2155 provides drop-down menus and other UI elements to configure and 2156 control the VM during runtime. Valid parameters are: 2157 2158 ``show-cursor=on|off`` : Force showing the mouse cursor 2159 2160 ``left-command-key=on|off`` : Disable forwarding left command key to host 2161 2162 ``egl-headless[,rendernode=<file>]`` 2163 Offload all OpenGL operations to a local DRI device. For any 2164 graphical display, this display needs to be paired with either 2165 VNC or SPICE displays. 2166 2167 ``vnc=<display>`` 2168 Start a VNC server on display <display> 2169 2170 ``none`` 2171 Do not display video output. The guest will still see an 2172 emulated graphics card, but its output will not be displayed to 2173 the QEMU user. This option differs from the -nographic option in 2174 that it only affects what is done with video output; -nographic 2175 also changes the destination of the serial and parallel port 2176 data. 2177ERST 2178 2179DEF("nographic", 0, QEMU_OPTION_nographic, 2180 "-nographic disable graphical output and redirect serial I/Os to console\n", 2181 QEMU_ARCH_ALL) 2182SRST 2183``-nographic`` 2184 Normally, if QEMU is compiled with graphical window support, it 2185 displays output such as guest graphics, guest console, and the QEMU 2186 monitor in a window. With this option, you can totally disable 2187 graphical output so that QEMU is a simple command line application. 2188 The emulated serial port is redirected on the console and muxed with 2189 the monitor (unless redirected elsewhere explicitly). Therefore, you 2190 can still use QEMU to debug a Linux kernel with a serial console. 2191 Use C-a h for help on switching between the console and monitor. 2192ERST 2193 2194#ifdef CONFIG_SPICE 2195DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2196 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2197 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2198 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2199 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2200 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2201 " [,tls-ciphers=<list>]\n" 2202 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2203 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2204 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2205 " [,password-secret=<secret-id>]\n" 2206 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2207 " [,jpeg-wan-compression=[auto|never|always]]\n" 2208 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2209 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2210 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2211 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2212 " [,gl=[on|off]][,rendernode=<file>]\n" 2213 " enable spice\n" 2214 " at least one of {port, tls-port} is mandatory\n", 2215 QEMU_ARCH_ALL) 2216#endif 2217SRST 2218``-spice option[,option[,...]]`` 2219 Enable the spice remote desktop protocol. Valid options are 2220 2221 ``port=<nr>`` 2222 Set the TCP port spice is listening on for plaintext channels. 2223 2224 ``addr=<addr>`` 2225 Set the IP address spice is listening on. Default is any 2226 address. 2227 2228 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2229 Force using the specified IP version. 2230 2231 ``password-secret=<secret-id>`` 2232 Set the ID of the ``secret`` object containing the password 2233 you need to authenticate. 2234 2235 ``sasl=on|off`` 2236 Require that the client use SASL to authenticate with the spice. 2237 The exact choice of authentication method used is controlled 2238 from the system / user's SASL configuration file for the 'qemu' 2239 service. This is typically found in /etc/sasl2/qemu.conf. If 2240 running QEMU as an unprivileged user, an environment variable 2241 SASL\_CONF\_PATH can be used to make it search alternate 2242 locations for the service config. While some SASL auth methods 2243 can also provide data encryption (eg GSSAPI), it is recommended 2244 that SASL always be combined with the 'tls' and 'x509' settings 2245 to enable use of SSL and server certificates. This ensures a 2246 data encryption preventing compromise of authentication 2247 credentials. 2248 2249 ``disable-ticketing=on|off`` 2250 Allow client connects without authentication. 2251 2252 ``disable-copy-paste=on|off`` 2253 Disable copy paste between the client and the guest. 2254 2255 ``disable-agent-file-xfer=on|off`` 2256 Disable spice-vdagent based file-xfer between the client and the 2257 guest. 2258 2259 ``tls-port=<nr>`` 2260 Set the TCP port spice is listening on for encrypted channels. 2261 2262 ``x509-dir=<dir>`` 2263 Set the x509 file directory. Expects same filenames as -vnc 2264 $display,x509=$dir 2265 2266 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2267 The x509 file names can also be configured individually. 2268 2269 ``tls-ciphers=<list>`` 2270 Specify which ciphers to use. 2271 2272 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2273 Force specific channel to be used with or without TLS 2274 encryption. The options can be specified multiple times to 2275 configure multiple channels. The special name "default" can be 2276 used to set the default mode. For channels which are not 2277 explicitly forced into one mode the spice client is allowed to 2278 pick tls/plaintext as he pleases. 2279 2280 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2281 Configure image compression (lossless). Default is auto\_glz. 2282 2283 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2284 Configure wan image compression (lossy for slow links). Default 2285 is auto. 2286 2287 ``streaming-video=[off|all|filter]`` 2288 Configure video stream detection. Default is off. 2289 2290 ``agent-mouse=[on|off]`` 2291 Enable/disable passing mouse events via vdagent. Default is on. 2292 2293 ``playback-compression=[on|off]`` 2294 Enable/disable audio stream compression (using celt 0.5.1). 2295 Default is on. 2296 2297 ``seamless-migration=[on|off]`` 2298 Enable/disable spice seamless migration. Default is off. 2299 2300 ``gl=[on|off]`` 2301 Enable/disable OpenGL context. Default is off. 2302 2303 ``rendernode=<file>`` 2304 DRM render node for OpenGL rendering. If not specified, it will 2305 pick the first available. (Since 2.9) 2306ERST 2307 2308DEF("portrait", 0, QEMU_OPTION_portrait, 2309 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2310 QEMU_ARCH_ALL) 2311SRST 2312``-portrait`` 2313 Rotate graphical output 90 deg left (only PXA LCD). 2314ERST 2315 2316DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2317 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2318 QEMU_ARCH_ALL) 2319SRST 2320``-rotate deg`` 2321 Rotate graphical output some deg left (only PXA LCD). 2322ERST 2323 2324DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2325 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2326 " select video card type\n", QEMU_ARCH_ALL) 2327SRST 2328``-vga type`` 2329 Select type of VGA card to emulate. Valid values for type are 2330 2331 ``cirrus`` 2332 Cirrus Logic GD5446 Video card. All Windows versions starting 2333 from Windows 95 should recognize and use this graphic card. For 2334 optimal performances, use 16 bit color depth in the guest and 2335 the host OS. (This card was the default before QEMU 2.2) 2336 2337 ``std`` 2338 Standard VGA card with Bochs VBE extensions. If your guest OS 2339 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2340 you want to use high resolution modes (>= 1280x1024x16) then you 2341 should use this option. (This card is the default since QEMU 2342 2.2) 2343 2344 ``vmware`` 2345 VMWare SVGA-II compatible adapter. Use it if you have 2346 sufficiently recent XFree86/XOrg server or Windows guest with a 2347 driver for this card. 2348 2349 ``qxl`` 2350 QXL paravirtual graphic card. It is VGA compatible (including 2351 VESA 2.0 VBE support). Works best with qxl guest drivers 2352 installed though. Recommended choice when using the spice 2353 protocol. 2354 2355 ``tcx`` 2356 (sun4m only) Sun TCX framebuffer. This is the default 2357 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2358 colour depths at a fixed resolution of 1024x768. 2359 2360 ``cg3`` 2361 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2362 framebuffer for sun4m machines available in both 1024x768 2363 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2364 wishing to run older Solaris versions. 2365 2366 ``virtio`` 2367 Virtio VGA card. 2368 2369 ``none`` 2370 Disable VGA card. 2371ERST 2372 2373DEF("full-screen", 0, QEMU_OPTION_full_screen, 2374 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2375SRST 2376``-full-screen`` 2377 Start in full screen. 2378ERST 2379 2380DEF("g", HAS_ARG, QEMU_OPTION_g , 2381 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2382 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2383SRST 2384``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2385 Set the initial graphical resolution and depth (PPC, SPARC only). 2386 2387 For PPC the default is 800x600x32. 2388 2389 For SPARC with the TCX graphics device, the default is 1024x768x8 2390 with the option of 1024x768x24. For cgthree, the default is 2391 1024x768x8 with the option of 1152x900x8 for people who wish to use 2392 OBP. 2393ERST 2394 2395DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2396 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2397SRST 2398``-vnc display[,option[,option[,...]]]`` 2399 Normally, if QEMU is compiled with graphical window support, it 2400 displays output such as guest graphics, guest console, and the QEMU 2401 monitor in a window. With this option, you can have QEMU listen on 2402 VNC display display and redirect the VGA display over the VNC 2403 session. It is very useful to enable the usb tablet device when 2404 using this option (option ``-device usb-tablet``). When using the 2405 VNC display, you must use the ``-k`` parameter to set the keyboard 2406 layout if you are not using en-us. Valid syntax for the display is 2407 2408 ``to=L`` 2409 With this option, QEMU will try next available VNC displays, 2410 until the number L, if the origianlly defined "-vnc display" is 2411 not available, e.g. port 5900+display is already used by another 2412 application. By default, to=0. 2413 2414 ``host:d`` 2415 TCP connections will only be allowed from host on display d. By 2416 convention the TCP port is 5900+d. Optionally, host can be 2417 omitted in which case the server will accept connections from 2418 any host. 2419 2420 ``unix:path`` 2421 Connections will be allowed over UNIX domain sockets where path 2422 is the location of a unix socket to listen for connections on. 2423 2424 ``none`` 2425 VNC is initialized but not started. The monitor ``change`` 2426 command can be used to later start the VNC server. 2427 2428 Following the display value there may be one or more option flags 2429 separated by commas. Valid options are 2430 2431 ``reverse=on|off`` 2432 Connect to a listening VNC client via a "reverse" connection. 2433 The client is specified by the display. For reverse network 2434 connections (host:d,``reverse``), the d argument is a TCP port 2435 number, not a display number. 2436 2437 ``websocket=on|off`` 2438 Opens an additional TCP listening port dedicated to VNC 2439 Websocket connections. If a bare websocket option is given, the 2440 Websocket port is 5700+display. An alternative port can be 2441 specified with the syntax ``websocket``\ =port. 2442 2443 If host is specified connections will only be allowed from this 2444 host. It is possible to control the websocket listen address 2445 independently, using the syntax ``websocket``\ =host:port. 2446 2447 If no TLS credentials are provided, the websocket connection 2448 runs in unencrypted mode. If TLS credentials are provided, the 2449 websocket connection requires encrypted client connections. 2450 2451 ``password=on|off`` 2452 Require that password based authentication is used for client 2453 connections. 2454 2455 The password must be set separately using the ``set_password`` 2456 command in the :ref:`QEMU monitor`. The 2457 syntax to change your password is: 2458 ``set_password <protocol> <password>`` where <protocol> could be 2459 either "vnc" or "spice". 2460 2461 If you would like to change <protocol> password expiration, you 2462 should use ``expire_password <protocol> <expiration-time>`` 2463 where expiration time could be one of the following options: 2464 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2465 make password expire in 60 seconds, or 1335196800 to make 2466 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2467 this date and time). 2468 2469 You can also use keywords "now" or "never" for the expiration 2470 time to allow <protocol> password to expire immediately or never 2471 expire. 2472 2473 ``password-secret=<secret-id>`` 2474 Require that password based authentication is used for client 2475 connections, using the password provided by the ``secret`` 2476 object identified by ``secret-id``. 2477 2478 ``tls-creds=ID`` 2479 Provides the ID of a set of TLS credentials to use to secure the 2480 VNC server. They will apply to both the normal VNC server socket 2481 and the websocket socket (if enabled). Setting TLS credentials 2482 will cause the VNC server socket to enable the VeNCrypt auth 2483 mechanism. The credentials should have been previously created 2484 using the ``-object tls-creds`` argument. 2485 2486 ``tls-authz=ID`` 2487 Provides the ID of the QAuthZ authorization object against which 2488 the client's x509 distinguished name will validated. This object 2489 is only resolved at time of use, so can be deleted and recreated 2490 on the fly while the VNC server is active. If missing, it will 2491 default to denying access. 2492 2493 ``sasl=on|off`` 2494 Require that the client use SASL to authenticate with the VNC 2495 server. The exact choice of authentication method used is 2496 controlled from the system / user's SASL configuration file for 2497 the 'qemu' service. This is typically found in 2498 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2499 an environment variable SASL\_CONF\_PATH can be used to make it 2500 search alternate locations for the service config. While some 2501 SASL auth methods can also provide data encryption (eg GSSAPI), 2502 it is recommended that SASL always be combined with the 'tls' 2503 and 'x509' settings to enable use of SSL and server 2504 certificates. This ensures a data encryption preventing 2505 compromise of authentication credentials. See the 2506 :ref:`VNC security` section in the System Emulation Users Guide 2507 for details on using SASL authentication. 2508 2509 ``sasl-authz=ID`` 2510 Provides the ID of the QAuthZ authorization object against which 2511 the client's SASL username will validated. This object is only 2512 resolved at time of use, so can be deleted and recreated on the 2513 fly while the VNC server is active. If missing, it will default 2514 to denying access. 2515 2516 ``acl=on|off`` 2517 Legacy method for enabling authorization of clients against the 2518 x509 distinguished name and SASL username. It results in the 2519 creation of two ``authz-list`` objects with IDs of 2520 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2521 objects must be configured with the HMP ACL commands. 2522 2523 This option is deprecated and should no longer be used. The new 2524 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2525 2526 ``lossy=on|off`` 2527 Enable lossy compression methods (gradient, JPEG, ...). If this 2528 option is set, VNC client may receive lossy framebuffer updates 2529 depending on its encoding settings. Enabling this option can 2530 save a lot of bandwidth at the expense of quality. 2531 2532 ``non-adaptive=on|off`` 2533 Disable adaptive encodings. Adaptive encodings are enabled by 2534 default. An adaptive encoding will try to detect frequently 2535 updated screen regions, and send updates in these regions using 2536 a lossy encoding (like JPEG). This can be really helpful to save 2537 bandwidth when playing videos. Disabling adaptive encodings 2538 restores the original static behavior of encodings like Tight. 2539 2540 ``share=[allow-exclusive|force-shared|ignore]`` 2541 Set display sharing policy. 'allow-exclusive' allows clients to 2542 ask for exclusive access. As suggested by the rfb spec this is 2543 implemented by dropping other connections. Connecting multiple 2544 clients in parallel requires all clients asking for a shared 2545 session (vncviewer: -shared switch). This is the default. 2546 'force-shared' disables exclusive client access. Useful for 2547 shared desktop sessions, where you don't want someone forgetting 2548 specify -shared disconnect everybody else. 'ignore' completely 2549 ignores the shared flag and allows everybody connect 2550 unconditionally. Doesn't conform to the rfb spec but is 2551 traditional QEMU behavior. 2552 2553 ``key-delay-ms`` 2554 Set keyboard delay, for key down and key up events, in 2555 milliseconds. Default is 10. Keyboards are low-bandwidth 2556 devices, so this slowdown can help the device and guest to keep 2557 up and not lose events in case events are arriving in bulk. 2558 Possible causes for the latter are flaky network connections, or 2559 scripts for automated testing. 2560 2561 ``audiodev=audiodev`` 2562 Use the specified audiodev when the VNC client requests audio 2563 transmission. When not using an -audiodev argument, this option 2564 must be omitted, otherwise is must be present and specify a 2565 valid audiodev. 2566 2567 ``power-control=on|off`` 2568 Permit the remote client to issue shutdown, reboot or reset power 2569 control requests. 2570ERST 2571 2572ARCHHEADING(, QEMU_ARCH_I386) 2573 2574ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2575 2576DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2577 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2578 QEMU_ARCH_I386) 2579SRST 2580``-win2k-hack`` 2581 Use it when installing Windows 2000 to avoid a disk full bug. After 2582 Windows 2000 is installed, you no longer need this option (this 2583 option slows down the IDE transfers). 2584ERST 2585 2586DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2587 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2588 QEMU_ARCH_I386) 2589SRST 2590``-no-fd-bootchk`` 2591 Disable boot signature checking for floppy disks in BIOS. May be 2592 needed to boot from old floppy disks. 2593ERST 2594 2595DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2596 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2597SRST 2598``-no-acpi`` 2599 Disable ACPI (Advanced Configuration and Power Interface) support. 2600 Use it if your guest OS complains about ACPI problems (PC target 2601 machine only). 2602ERST 2603 2604DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2605 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2606SRST 2607``-no-hpet`` 2608 Disable HPET support. Deprecated, use '-machine hpet=off' instead. 2609ERST 2610 2611DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2612 "-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" 2613 " ACPI table description\n", QEMU_ARCH_I386) 2614SRST 2615``-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]...]`` 2616 Add ACPI table with specified header fields and context from 2617 specified files. For file=, take whole ACPI table from the specified 2618 files, including all ACPI headers (possible overridden by other 2619 options). For data=, only data portion of the table is used, all 2620 header information is specified in the command line. If a SLIC table 2621 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2622 fields will override the same in the RSDT and the FADT (a.k.a. 2623 FACP), in order to ensure the field matches required by the 2624 Microsoft SLIC spec and the ACPI spec. 2625ERST 2626 2627DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2628 "-smbios file=binary\n" 2629 " load SMBIOS entry from binary file\n" 2630 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2631 " [,uefi=on|off]\n" 2632 " specify SMBIOS type 0 fields\n" 2633 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2634 " [,uuid=uuid][,sku=str][,family=str]\n" 2635 " specify SMBIOS type 1 fields\n" 2636 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2637 " [,asset=str][,location=str]\n" 2638 " specify SMBIOS type 2 fields\n" 2639 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2640 " [,sku=str]\n" 2641 " specify SMBIOS type 3 fields\n" 2642 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2643 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2644 " [,processor-id=%d]\n" 2645 " specify SMBIOS type 4 fields\n" 2646 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2647 " specify SMBIOS type 8 fields\n" 2648 "-smbios type=11[,value=str][,path=filename]\n" 2649 " specify SMBIOS type 11 fields\n" 2650 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2651 " [,asset=str][,part=str][,speed=%d]\n" 2652 " specify SMBIOS type 17 fields\n" 2653 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2654 " specify SMBIOS type 41 fields\n", 2655 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2656SRST 2657``-smbios file=binary`` 2658 Load SMBIOS entry from binary file. 2659 2660``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2661 Specify SMBIOS type 0 fields 2662 2663``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2664 Specify SMBIOS type 1 fields 2665 2666``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2667 Specify SMBIOS type 2 fields 2668 2669``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2670 Specify SMBIOS type 3 fields 2671 2672``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2673 Specify SMBIOS type 4 fields 2674 2675``-smbios type=11[,value=str][,path=filename]`` 2676 Specify SMBIOS type 11 fields 2677 2678 This argument can be repeated multiple times, and values are added in the order they are parsed. 2679 Applications intending to use OEM strings data are encouraged to use their application name as 2680 a prefix for the value string. This facilitates passing information for multiple applications 2681 concurrently. 2682 2683 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2684 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2685 2686 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2687 the SMBIOS table in the order in which they appear. 2688 2689 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2690 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2691 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2692 data set, for example, by specifying the serial ID of a block device. 2693 2694 An example passing three strings is 2695 2696 .. parsed-literal:: 2697 2698 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2699 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2700 path=/some/file/with/oemstringsdata.txt 2701 2702 In the guest OS this is visible with the ``dmidecode`` command 2703 2704 .. parsed-literal:: 2705 2706 $ dmidecode -t 11 2707 Handle 0x0E00, DMI type 11, 5 bytes 2708 OEM Strings 2709 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2710 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2711 String 3: myapp:some extra data 2712 2713 2714``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2715 Specify SMBIOS type 17 fields 2716 2717``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2718 Specify SMBIOS type 41 fields 2719 2720 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2721 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2722 position on the PCI bus. 2723 2724 Here is an example of use: 2725 2726 .. parsed-literal:: 2727 2728 -netdev user,id=internet \\ 2729 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2730 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2731 2732 In the guest OS, the device should then appear as ``eno1``: 2733 2734 ..parsed-literal:: 2735 2736 $ ip -brief l 2737 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2738 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2739 2740 Currently, the PCI device has to be attached to the root bus. 2741 2742ERST 2743 2744DEFHEADING() 2745 2746DEFHEADING(Network options:) 2747 2748DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2749#ifdef CONFIG_SLIRP 2750 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2751 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2752 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2753 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2754 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2755#ifndef _WIN32 2756 "[,smb=dir[,smbserver=addr]]\n" 2757#endif 2758 " configure a user mode network backend with ID 'str',\n" 2759 " its DHCP server and optional services\n" 2760#endif 2761#ifdef _WIN32 2762 "-netdev tap,id=str,ifname=name\n" 2763 " configure a host TAP network backend with ID 'str'\n" 2764#else 2765 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2766 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2767 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2768 " [,poll-us=n]\n" 2769 " configure a host TAP network backend with ID 'str'\n" 2770 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2771 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2772 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2773 " to deconfigure it\n" 2774 " use '[down]script=no' to disable script execution\n" 2775 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2776 " configure it\n" 2777 " use 'fd=h' to connect to an already opened TAP interface\n" 2778 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2779 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2780 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2781 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2782 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2783 " use vhost=on to enable experimental in kernel accelerator\n" 2784 " (only has effect for virtio guests which use MSIX)\n" 2785 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2786 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2787 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2788 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2789 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2790 " spent on busy polling for vhost net\n" 2791 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2792 " configure a host TAP network backend with ID 'str' that is\n" 2793 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2794 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2795#endif 2796#ifdef __linux__ 2797 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2798 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2799 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2800 " [,rxcookie=rxcookie][,offset=offset]\n" 2801 " configure a network backend with ID 'str' connected to\n" 2802 " an Ethernet over L2TPv3 pseudowire.\n" 2803 " Linux kernel 3.3+ as well as most routers can talk\n" 2804 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2805 " VM to a router and even VM to Host. It is a nearly-universal\n" 2806 " standard (RFC3931). Note - this implementation uses static\n" 2807 " pre-configured tunnels (same as the Linux kernel).\n" 2808 " use 'src=' to specify source address\n" 2809 " use 'dst=' to specify destination address\n" 2810 " use 'udp=on' to specify udp encapsulation\n" 2811 " use 'srcport=' to specify source udp port\n" 2812 " use 'dstport=' to specify destination udp port\n" 2813 " use 'ipv6=on' to force v6\n" 2814 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2815 " well as a weak security measure\n" 2816 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2817 " use 'txcookie=0x012345678' to specify a txcookie\n" 2818 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2819 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2820 " use 'pincounter=on' to work around broken counter handling in peer\n" 2821 " use 'offset=X' to add an extra offset between header and data\n" 2822#endif 2823 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2824 " configure a network backend to connect to another network\n" 2825 " using a socket connection\n" 2826 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2827 " configure a network backend to connect to a multicast maddr and port\n" 2828 " use 'localaddr=addr' to specify the host address to send packets from\n" 2829 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2830 " configure a network backend to connect to another network\n" 2831 " using an UDP tunnel\n" 2832 "-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" 2833 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2834 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2835 " configure a network backend to connect to another network\n" 2836 " using a socket connection in stream mode.\n" 2837 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2838 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2839 " configure a network backend to connect to a multicast maddr and port\n" 2840 " use ``local.host=addr`` to specify the host address to send packets from\n" 2841 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2842 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2843 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2844 " configure a network backend to connect to another network\n" 2845 " using an UDP tunnel\n" 2846#ifdef CONFIG_VDE 2847 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2848 " configure a network backend to connect to port 'n' of a vde switch\n" 2849 " running on host and listening for incoming connections on 'socketpath'.\n" 2850 " Use group 'groupname' and mode 'octalmode' to change default\n" 2851 " ownership and permissions for communication port.\n" 2852#endif 2853#ifdef CONFIG_NETMAP 2854 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2855 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2856 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2857 " netmap device, defaults to '/dev/netmap')\n" 2858#endif 2859#ifdef CONFIG_POSIX 2860 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2861 " configure a vhost-user network, backed by a chardev 'dev'\n" 2862#endif 2863#ifdef __linux__ 2864 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2865 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2866 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2867 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2868#endif 2869#ifdef CONFIG_VMNET 2870 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2871 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2872 " configure a vmnet network backend in host mode with ID 'str',\n" 2873 " isolate this interface from others with 'isolated',\n" 2874 " configure the address range and choose a subnet mask,\n" 2875 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2876 " vmnet-host interfaces within this isolated network\n" 2877 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2878 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2879 " configure a vmnet network backend in shared mode with ID 'str',\n" 2880 " configure the address range and choose a subnet mask,\n" 2881 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2882 " isolate this interface from others with 'isolated'\n" 2883 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2884 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2885 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2886 " isolate this interface from others with 'isolated'\n" 2887#endif 2888 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2889 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2890DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2891 "-nic [tap|bridge|" 2892#ifdef CONFIG_SLIRP 2893 "user|" 2894#endif 2895#ifdef __linux__ 2896 "l2tpv3|" 2897#endif 2898#ifdef CONFIG_VDE 2899 "vde|" 2900#endif 2901#ifdef CONFIG_NETMAP 2902 "netmap|" 2903#endif 2904#ifdef CONFIG_POSIX 2905 "vhost-user|" 2906#endif 2907#ifdef CONFIG_VMNET 2908 "vmnet-host|vmnet-shared|vmnet-bridged|" 2909#endif 2910 "socket][,option][,...][mac=macaddr]\n" 2911 " initialize an on-board / default host NIC (using MAC address\n" 2912 " macaddr) and connect it to the given host network backend\n" 2913 "-nic none use it alone to have zero network devices (the default is to\n" 2914 " provided a 'user' network connection)\n", 2915 QEMU_ARCH_ALL) 2916DEF("net", HAS_ARG, QEMU_OPTION_net, 2917 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2918 " configure or create an on-board (or machine default) NIC and\n" 2919 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2920 "-net [" 2921#ifdef CONFIG_SLIRP 2922 "user|" 2923#endif 2924 "tap|" 2925 "bridge|" 2926#ifdef CONFIG_VDE 2927 "vde|" 2928#endif 2929#ifdef CONFIG_NETMAP 2930 "netmap|" 2931#endif 2932#ifdef CONFIG_VMNET 2933 "vmnet-host|vmnet-shared|vmnet-bridged|" 2934#endif 2935 "socket][,option][,option][,...]\n" 2936 " old way to initialize a host network interface\n" 2937 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2938SRST 2939``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2940 This option is a shortcut for configuring both the on-board 2941 (default) guest NIC hardware and the host network backend in one go. 2942 The host backend options are the same as with the corresponding 2943 ``-netdev`` options below. The guest NIC model can be set with 2944 ``model=modelname``. Use ``model=help`` to list the available device 2945 types. The hardware MAC address can be set with ``mac=macaddr``. 2946 2947 The following two example do exactly the same, to show how ``-nic`` 2948 can be used to shorten the command line length: 2949 2950 .. parsed-literal:: 2951 2952 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2953 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2954 2955``-nic none`` 2956 Indicate that no network devices should be configured. It is used to 2957 override the default configuration (default NIC with "user" host 2958 network backend) which is activated if no other networking options 2959 are provided. 2960 2961``-netdev user,id=id[,option][,option][,...]`` 2962 Configure user mode host network backend which requires no 2963 administrator privilege to run. Valid options are: 2964 2965 ``id=id`` 2966 Assign symbolic name for use in monitor commands. 2967 2968 ``ipv4=on|off and ipv6=on|off`` 2969 Specify that either IPv4 or IPv6 must be enabled. If neither is 2970 specified both protocols are enabled. 2971 2972 ``net=addr[/mask]`` 2973 Set IP network address the guest will see. Optionally specify 2974 the netmask, either in the form a.b.c.d or as number of valid 2975 top-most bits. Default is 10.0.2.0/24. 2976 2977 ``host=addr`` 2978 Specify the guest-visible address of the host. Default is the 2979 2nd IP in the guest network, i.e. x.x.x.2. 2980 2981 ``ipv6-net=addr[/int]`` 2982 Set IPv6 network address the guest will see (default is 2983 fec0::/64). The network prefix is given in the usual hexadecimal 2984 IPv6 address notation. The prefix size is optional, and is given 2985 as the number of valid top-most bits (default is 64). 2986 2987 ``ipv6-host=addr`` 2988 Specify the guest-visible IPv6 address of the host. Default is 2989 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2990 2991 ``restrict=on|off`` 2992 If this option is enabled, the guest will be isolated, i.e. it 2993 will not be able to contact the host and no guest IP packets 2994 will be routed over the host to the outside. This option does 2995 not affect any explicitly set forwarding rules. 2996 2997 ``hostname=name`` 2998 Specifies the client hostname reported by the built-in DHCP 2999 server. 3000 3001 ``dhcpstart=addr`` 3002 Specify the first of the 16 IPs the built-in DHCP server can 3003 assign. Default is the 15th to 31st IP in the guest network, 3004 i.e. x.x.x.15 to x.x.x.31. 3005 3006 ``dns=addr`` 3007 Specify the guest-visible address of the virtual nameserver. The 3008 address must be different from the host address. Default is the 3009 3rd IP in the guest network, i.e. x.x.x.3. 3010 3011 ``ipv6-dns=addr`` 3012 Specify the guest-visible address of the IPv6 virtual 3013 nameserver. The address must be different from the host address. 3014 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3015 3016 ``dnssearch=domain`` 3017 Provides an entry for the domain-search list sent by the 3018 built-in DHCP server. More than one domain suffix can be 3019 transmitted by specifying this option multiple times. If 3020 supported, this will cause the guest to automatically try to 3021 append the given domain suffix(es) in case a domain name can not 3022 be resolved. 3023 3024 Example: 3025 3026 .. parsed-literal:: 3027 3028 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3029 3030 ``domainname=domain`` 3031 Specifies the client domain name reported by the built-in DHCP 3032 server. 3033 3034 ``tftp=dir`` 3035 When using the user mode network stack, activate a built-in TFTP 3036 server. The files in dir will be exposed as the root of a TFTP 3037 server. The TFTP client on the guest must be configured in 3038 binary mode (use the command ``bin`` of the Unix TFTP client). 3039 3040 ``tftp-server-name=name`` 3041 In BOOTP reply, broadcast name as the "TFTP server name" 3042 (RFC2132 option 66). This can be used to advise the guest to 3043 load boot files or configurations from a different server than 3044 the host address. 3045 3046 ``bootfile=file`` 3047 When using the user mode network stack, broadcast file as the 3048 BOOTP filename. In conjunction with ``tftp``, this can be used 3049 to network boot a guest from a local directory. 3050 3051 Example (using pxelinux): 3052 3053 .. parsed-literal:: 3054 3055 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3056 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3057 3058 ``smb=dir[,smbserver=addr]`` 3059 When using the user mode network stack, activate a built-in SMB 3060 server so that Windows OSes can access to the host files in 3061 ``dir`` transparently. The IP address of the SMB server can be 3062 set to addr. By default the 4th IP in the guest network is used, 3063 i.e. x.x.x.4. 3064 3065 In the guest Windows OS, the line: 3066 3067 :: 3068 3069 10.0.2.4 smbserver 3070 3071 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3072 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3073 NT/2000). 3074 3075 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3076 3077 Note that a SAMBA server must be installed on the host OS. 3078 3079 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3080 Redirect incoming TCP or UDP connections to the host port 3081 hostport to the guest IP address guestaddr on guest port 3082 guestport. If guestaddr is not specified, its value is x.x.x.15 3083 (default first address given by the built-in DHCP server). By 3084 specifying hostaddr, the rule can be bound to a specific host 3085 interface. If no connection type is set, TCP is used. This 3086 option can be given multiple times. 3087 3088 For example, to redirect host X11 connection from screen 1 to 3089 guest screen 0, use the following: 3090 3091 .. parsed-literal:: 3092 3093 # on the host 3094 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3095 # this host xterm should open in the guest X11 server 3096 xterm -display :1 3097 3098 To redirect telnet connections from host port 5555 to telnet 3099 port on the guest, use the following: 3100 3101 .. parsed-literal:: 3102 3103 # on the host 3104 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3105 telnet localhost 5555 3106 3107 Then when you use on the host ``telnet localhost 5555``, you 3108 connect to the guest telnet server. 3109 3110 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3111 Forward guest TCP connections to the IP address server on port 3112 port to the character device dev or to a program executed by 3113 cmd:command which gets spawned for each connection. This option 3114 can be given multiple times. 3115 3116 You can either use a chardev directly and have that one used 3117 throughout QEMU's lifetime, like in the following example: 3118 3119 .. parsed-literal:: 3120 3121 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3122 # the guest accesses it 3123 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3124 3125 Or you can execute a command on every TCP connection established 3126 by the guest, so that QEMU behaves similar to an inetd process 3127 for that virtual server: 3128 3129 .. parsed-literal:: 3130 3131 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3132 # and connect the TCP stream to its stdin/stdout 3133 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3134 3135``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3136 Configure a host TAP network backend with ID id. 3137 3138 Use the network script file to configure it and the network script 3139 dfile to deconfigure it. If name is not provided, the OS 3140 automatically provides one. The default network configure script is 3141 ``/etc/qemu-ifup`` and the default network deconfigure script is 3142 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3143 disable script execution. 3144 3145 If running QEMU as an unprivileged user, use the network helper 3146 to configure the TAP interface and attach it to the bridge. 3147 The default network helper executable is 3148 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3149 ``br0``. 3150 3151 ``fd``\ =h can be used to specify the handle of an already opened 3152 host TAP interface. 3153 3154 Examples: 3155 3156 .. parsed-literal:: 3157 3158 #launch a QEMU instance with the default network script 3159 |qemu_system| linux.img -nic tap 3160 3161 .. parsed-literal:: 3162 3163 #launch a QEMU instance with two NICs, each one connected 3164 #to a TAP device 3165 |qemu_system| linux.img \\ 3166 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3167 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3168 3169 .. parsed-literal:: 3170 3171 #launch a QEMU instance with the default network helper to 3172 #connect a TAP device to bridge br0 3173 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3174 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3175 3176``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3177 Connect a host TAP network interface to a host bridge device. 3178 3179 Use the network helper helper to configure the TAP interface and 3180 attach it to the bridge. The default network helper executable is 3181 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3182 ``br0``. 3183 3184 Examples: 3185 3186 .. parsed-literal:: 3187 3188 #launch a QEMU instance with the default network helper to 3189 #connect a TAP device to bridge br0 3190 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3191 3192 .. parsed-literal:: 3193 3194 #launch a QEMU instance with the default network helper to 3195 #connect a TAP device to bridge qemubr0 3196 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3197 3198``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3199 This host network backend can be used to connect the guest's network 3200 to another QEMU virtual machine using a TCP socket connection. If 3201 ``listen`` is specified, QEMU waits for incoming connections on port 3202 (host is optional). ``connect`` is used to connect to another QEMU 3203 instance using the ``listen`` option. ``fd``\ =h specifies an 3204 already opened TCP socket. 3205 3206 Example: 3207 3208 .. parsed-literal:: 3209 3210 # launch a first QEMU instance 3211 |qemu_system| linux.img \\ 3212 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3213 -netdev socket,id=n1,listen=:1234 3214 # connect the network of this instance to the network of the first instance 3215 |qemu_system| linux.img \\ 3216 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3217 -netdev socket,id=n2,connect=127.0.0.1:1234 3218 3219``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3220 Configure a socket host network backend to share the guest's network 3221 traffic with another QEMU virtual machines using a UDP multicast 3222 socket, effectively making a bus for every QEMU with same multicast 3223 address maddr and port. NOTES: 3224 3225 1. Several QEMU can be running on different hosts and share same bus 3226 (assuming correct multicast setup for these hosts). 3227 3228 2. mcast support is compatible with User Mode Linux (argument 3229 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3230 3231 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3232 3233 Example: 3234 3235 .. parsed-literal:: 3236 3237 # launch one QEMU instance 3238 |qemu_system| linux.img \\ 3239 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3240 -netdev socket,id=n1,mcast=230.0.0.1:1234 3241 # launch another QEMU instance on same "bus" 3242 |qemu_system| linux.img \\ 3243 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3244 -netdev socket,id=n2,mcast=230.0.0.1:1234 3245 # launch yet another QEMU instance on same "bus" 3246 |qemu_system| linux.img \\ 3247 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3248 -netdev socket,id=n3,mcast=230.0.0.1:1234 3249 3250 Example (User Mode Linux compat.): 3251 3252 .. parsed-literal:: 3253 3254 # launch QEMU instance (note mcast address selected is UML's default) 3255 |qemu_system| linux.img \\ 3256 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3257 -netdev socket,id=n1,mcast=239.192.168.1:1102 3258 # launch UML 3259 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3260 3261 Example (send packets from host's 1.2.3.4): 3262 3263 .. parsed-literal:: 3264 3265 |qemu_system| linux.img \\ 3266 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3267 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3268 3269``-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]`` 3270 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3271 is a popular protocol to transport Ethernet (and other Layer 2) data 3272 frames between two systems. It is present in routers, firewalls and 3273 the Linux kernel (from version 3.3 onwards). 3274 3275 This transport allows a VM to communicate to another VM, router or 3276 firewall directly. 3277 3278 ``src=srcaddr`` 3279 source address (mandatory) 3280 3281 ``dst=dstaddr`` 3282 destination address (mandatory) 3283 3284 ``udp`` 3285 select udp encapsulation (default is ip). 3286 3287 ``srcport=srcport`` 3288 source udp port. 3289 3290 ``dstport=dstport`` 3291 destination udp port. 3292 3293 ``ipv6`` 3294 force v6, otherwise defaults to v4. 3295 3296 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3297 Cookies are a weak form of security in the l2tpv3 specification. 3298 Their function is mostly to prevent misconfiguration. By default 3299 they are 32 bit. 3300 3301 ``cookie64`` 3302 Set cookie size to 64 bit instead of the default 32 3303 3304 ``counter=off`` 3305 Force a 'cut-down' L2TPv3 with no counter as in 3306 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3307 3308 ``pincounter=on`` 3309 Work around broken counter handling in peer. This may also help 3310 on networks which have packet reorder. 3311 3312 ``offset=offset`` 3313 Add an extra offset between header and data 3314 3315 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3316 the bridge br-lan on the remote Linux host 1.2.3.4: 3317 3318 .. parsed-literal:: 3319 3320 # Setup tunnel on linux host using raw ip as encapsulation 3321 # on 1.2.3.4 3322 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3323 encap udp udp_sport 16384 udp_dport 16384 3324 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3325 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3326 ifconfig vmtunnel0 mtu 1500 3327 ifconfig vmtunnel0 up 3328 brctl addif br-lan vmtunnel0 3329 3330 3331 # on 4.3.2.1 3332 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3333 3334 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3335 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3336 3337``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3338 Configure VDE backend to connect to PORT n of a vde switch running 3339 on host and listening for incoming connections on socketpath. Use 3340 GROUP groupname and MODE octalmode to change default ownership and 3341 permissions for communication port. This option is only available if 3342 QEMU has been compiled with vde support enabled. 3343 3344 Example: 3345 3346 .. parsed-literal:: 3347 3348 # launch vde switch 3349 vde_switch -F -sock /tmp/myswitch 3350 # launch QEMU instance 3351 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3352 3353``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3354 Establish a vhost-user netdev, backed by a chardev id. The chardev 3355 should be a unix domain socket backed one. The vhost-user uses a 3356 specifically defined protocol to pass vhost ioctl replacement 3357 messages to an application on the other end of the socket. On 3358 non-MSIX guests, the feature can be forced with vhostforce. Use 3359 'queues=n' to specify the number of queues to be created for 3360 multiqueue vhost-user. 3361 3362 Example: 3363 3364 :: 3365 3366 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3367 -numa node,memdev=mem \ 3368 -chardev socket,id=chr0,path=/path/to/socket \ 3369 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3370 -device virtio-net-pci,netdev=net0 3371 3372``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3373 Establish a vhost-vdpa netdev. 3374 3375 vDPA device is a device that uses a datapath which complies with 3376 the virtio specifications with a vendor specific control path. 3377 vDPA devices can be both physically located on the hardware or 3378 emulated by software. 3379 3380``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3381 Create a hub port on the emulated hub with ID hubid. 3382 3383 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3384 instead of a single netdev. Alternatively, you can also connect the 3385 hubport to another netdev with ID nd by using the ``netdev=nd`` 3386 option. 3387 3388``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3389 Legacy option to configure or create an on-board (or machine 3390 default) Network Interface Card(NIC) and connect it either to the 3391 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3392 If model is omitted, then the default NIC model associated with the 3393 machine type is used. Note that the default NIC model may change in 3394 future QEMU releases, so it is highly recommended to always specify 3395 a model. Optionally, the MAC address can be changed to mac, the 3396 device address set to addr (PCI cards only), and a name can be 3397 assigned for use in monitor commands. Optionally, for PCI cards, you 3398 can specify the number v of MSI-X vectors that the card should have; 3399 this option currently only affects virtio cards; set v = 0 to 3400 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3401 created. QEMU can emulate several different models of network card. 3402 Use ``-net nic,model=help`` for a list of available devices for your 3403 target. 3404 3405``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3406 Configure a host network backend (with the options corresponding to 3407 the same ``-netdev`` option) and connect it to the emulated hub 0 3408 (the default hub). Use name to specify the name of the hub port. 3409ERST 3410 3411DEFHEADING() 3412 3413DEFHEADING(Character device options:) 3414 3415DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3416 "-chardev help\n" 3417 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3418 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3419 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3420 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3421 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3422 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3423 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3424 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3425 " [,logfile=PATH][,logappend=on|off]\n" 3426 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3427 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3428 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3429 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3430 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3431 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3432#ifdef _WIN32 3433 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3434 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3435#else 3436 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3437 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3438#endif 3439#ifdef CONFIG_BRLAPI 3440 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3441#endif 3442#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3443 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3444 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3445#endif 3446#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3447 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3448#endif 3449#if defined(CONFIG_SPICE) 3450 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3451 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3452#endif 3453 , QEMU_ARCH_ALL 3454) 3455 3456SRST 3457The general form of a character device option is: 3458 3459``-chardev backend,id=id[,mux=on|off][,options]`` 3460 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3461 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3462 ``pty``, ``stdio``, ``braille``, ``parallel``, 3463 ``spicevmc``, ``spiceport``. The specific backend will determine the 3464 applicable options. 3465 3466 Use ``-chardev help`` to print all available chardev backend types. 3467 3468 All devices must have an id, which can be any string up to 127 3469 characters long. It is used to uniquely identify this device in 3470 other command line directives. 3471 3472 A character device may be used in multiplexing mode by multiple 3473 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3474 a "1:N" device, and here the "1" end is your specified chardev 3475 backend, and the "N" end is the various parts of QEMU that can talk 3476 to a chardev. If you create a chardev with ``id=myid`` and 3477 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3478 and you can then configure multiple front ends to use that chardev 3479 ID for their input/output. Up to four different front ends can be 3480 connected to a single multiplexed chardev. (Without multiplexing 3481 enabled, a chardev can only be used by a single front end.) For 3482 instance you could use this to allow a single stdio chardev to be 3483 used by two serial ports and the QEMU monitor: 3484 3485 :: 3486 3487 -chardev stdio,mux=on,id=char0 \ 3488 -mon chardev=char0,mode=readline \ 3489 -serial chardev:char0 \ 3490 -serial chardev:char0 3491 3492 You can have more than one multiplexer in a system configuration; 3493 for instance you could have a TCP port multiplexed between UART 0 3494 and UART 1, and stdio multiplexed between the QEMU monitor and a 3495 parallel port: 3496 3497 :: 3498 3499 -chardev stdio,mux=on,id=char0 \ 3500 -mon chardev=char0,mode=readline \ 3501 -parallel chardev:char0 \ 3502 -chardev tcp,...,mux=on,id=char1 \ 3503 -serial chardev:char1 \ 3504 -serial chardev:char1 3505 3506 When you're using a multiplexed character device, some escape 3507 sequences are interpreted in the input. See the chapter about 3508 :ref:`keys in the character backend multiplexer` in the 3509 System Emulation Users Guide for more details. 3510 3511 Note that some other command line options may implicitly create 3512 multiplexed character backends; for instance ``-serial mon:stdio`` 3513 creates a multiplexed stdio backend connected to the serial port and 3514 the QEMU monitor, and ``-nographic`` also multiplexes the console 3515 and the monitor to stdio. 3516 3517 There is currently no support for multiplexing in the other 3518 direction (where a single QEMU front end takes input and output from 3519 multiple chardevs). 3520 3521 Every backend supports the ``logfile`` option, which supplies the 3522 path to a file to record all data transmitted via the backend. The 3523 ``logappend`` option controls whether the log file will be truncated 3524 or appended to when opened. 3525 3526The available backends are: 3527 3528``-chardev null,id=id`` 3529 A void device. This device will not emit any data, and will drop any 3530 data it receives. The null backend does not take any options. 3531 3532``-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]`` 3533 Create a two-way stream socket, which can be either a TCP or a unix 3534 socket. A unix socket will be created if ``path`` is specified. 3535 Behaviour is undefined if TCP options are specified for a unix 3536 socket. 3537 3538 ``server=on|off`` specifies that the socket shall be a listening socket. 3539 3540 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3541 to connect to a listening socket. 3542 3543 ``telnet=on|off`` specifies that traffic on the socket should interpret 3544 telnet escape sequences. 3545 3546 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3547 communication. 3548 3549 ``reconnect`` sets the timeout for reconnecting on non-server 3550 sockets when the remote end goes away. qemu will delay this many 3551 seconds and then attempt to reconnect. Zero disables reconnecting, 3552 and is the default. 3553 3554 ``tls-creds`` requests enablement of the TLS protocol for 3555 encryption, and specifies the id of the TLS credentials to use for 3556 the handshake. The credentials must be previously created with the 3557 ``-object tls-creds`` argument. 3558 3559 ``tls-auth`` provides the ID of the QAuthZ authorization object 3560 against which the client's x509 distinguished name will be 3561 validated. This object is only resolved at time of use, so can be 3562 deleted and recreated on the fly while the chardev server is active. 3563 If missing, it will default to denying access. 3564 3565 TCP and unix socket options are given below: 3566 3567 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3568 ``host`` for a listening socket specifies the local address to 3569 be bound. For a connecting socket species the remote host to 3570 connect to. ``host`` is optional for listening sockets. If not 3571 specified it defaults to ``0.0.0.0``. 3572 3573 ``port`` for a listening socket specifies the local port to be 3574 bound. For a connecting socket specifies the port on the remote 3575 host to connect to. ``port`` can be given as either a port 3576 number or a service name. ``port`` is required. 3577 3578 ``to`` is only relevant to listening sockets. If it is 3579 specified, and ``port`` cannot be bound, QEMU will attempt to 3580 bind to subsequent ports up to and including ``to`` until it 3581 succeeds. ``to`` must be specified as a port number. 3582 3583 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3584 or IPv6 must be used. If neither is specified the socket may 3585 use either protocol. 3586 3587 ``nodelay=on|off`` disables the Nagle algorithm. 3588 3589 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3590 ``path`` specifies the local path of the unix socket. ``path`` 3591 is required. 3592 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3593 rather than the filesystem. Optional, defaults to false. 3594 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3595 rather than the full sun_path length. Optional, defaults to true. 3596 3597``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3598 Sends all traffic from the guest to a remote host over UDP. 3599 3600 ``host`` specifies the remote host to connect to. If not specified 3601 it defaults to ``localhost``. 3602 3603 ``port`` specifies the port on the remote host to connect to. 3604 ``port`` is required. 3605 3606 ``localaddr`` specifies the local address to bind to. If not 3607 specified it defaults to ``0.0.0.0``. 3608 3609 ``localport`` specifies the local port to bind to. If not specified 3610 any available local port will be used. 3611 3612 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3613 If neither is specified the device may use either protocol. 3614 3615``-chardev msmouse,id=id`` 3616 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3617 does not take any options. 3618 3619``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3620 Connect to a QEMU text console. ``vc`` may optionally be given a 3621 specific size. 3622 3623 ``width`` and ``height`` specify the width and height respectively 3624 of the console, in pixels. 3625 3626 ``cols`` and ``rows`` specify that the console be sized to fit a 3627 text console with the given dimensions. 3628 3629``-chardev ringbuf,id=id[,size=size]`` 3630 Create a ring buffer with fixed size ``size``. size must be a power 3631 of two and defaults to ``64K``. 3632 3633``-chardev file,id=id,path=path[,input-path=input-path]`` 3634 Log all traffic received from the guest to a file. 3635 3636 ``path`` specifies the path of the file to be opened. This file will 3637 be created if it does not already exist, and overwritten if it does. 3638 ``path`` is required. 3639 3640 If ``input-path`` is specified, this is the path of a second file 3641 which will be used for input. If ``input-path`` is not specified, 3642 no input will be available from the chardev. 3643 3644 Note that ``input-path`` is not supported on Windows hosts. 3645 3646``-chardev pipe,id=id,path=path`` 3647 Create a two-way connection to the guest. The behaviour differs 3648 slightly between Windows hosts and other hosts: 3649 3650 On Windows, a single duplex pipe will be created at 3651 ``\\.pipe\path``. 3652 3653 On other hosts, 2 pipes will be created called ``path.in`` and 3654 ``path.out``. Data written to ``path.in`` will be received by the 3655 guest. Data written by the guest can be read from ``path.out``. QEMU 3656 will not create these fifos, and requires them to be present. 3657 3658 ``path`` forms part of the pipe path as described above. ``path`` is 3659 required. 3660 3661``-chardev console,id=id`` 3662 Send traffic from the guest to QEMU's standard output. ``console`` 3663 does not take any options. 3664 3665 ``console`` is only available on Windows hosts. 3666 3667``-chardev serial,id=id,path=path`` 3668 Send traffic from the guest to a serial device on the host. 3669 3670 On Unix hosts serial will actually accept any tty device, not only 3671 serial lines. 3672 3673 ``path`` specifies the name of the serial device to open. 3674 3675``-chardev pty,id=id`` 3676 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3677 does not take any options. 3678 3679 ``pty`` is not available on Windows hosts. 3680 3681``-chardev stdio,id=id[,signal=on|off]`` 3682 Connect to standard input and standard output of the QEMU process. 3683 3684 ``signal`` controls if signals are enabled on the terminal, that 3685 includes exiting QEMU with the key sequence Control-c. This option 3686 is enabled by default, use ``signal=off`` to disable it. 3687 3688``-chardev braille,id=id`` 3689 Connect to a local BrlAPI server. ``braille`` does not take any 3690 options. 3691 3692``-chardev parallel,id=id,path=path`` 3693 \ 3694 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3695 hosts. 3696 3697 Connect to a local parallel port. 3698 3699 ``path`` specifies the path to the parallel port device. ``path`` is 3700 required. 3701 3702``-chardev spicevmc,id=id,debug=debug,name=name`` 3703 ``spicevmc`` is only available when spice support is built in. 3704 3705 ``debug`` debug level for spicevmc 3706 3707 ``name`` name of spice channel to connect to 3708 3709 Connect to a spice virtual machine channel, such as vdiport. 3710 3711``-chardev spiceport,id=id,debug=debug,name=name`` 3712 ``spiceport`` is only available when spice support is built in. 3713 3714 ``debug`` debug level for spicevmc 3715 3716 ``name`` name of spice port to connect to 3717 3718 Connect to a spice port, allowing a Spice client to handle the 3719 traffic identified by a name (preferably a fqdn). 3720ERST 3721 3722DEFHEADING() 3723 3724#ifdef CONFIG_TPM 3725DEFHEADING(TPM device options:) 3726 3727DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3728 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3729 " use path to provide path to a character device; default is /dev/tpm0\n" 3730 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3731 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3732 "-tpmdev emulator,id=id,chardev=dev\n" 3733 " configure the TPM device using chardev backend\n", 3734 QEMU_ARCH_ALL) 3735SRST 3736The general form of a TPM device option is: 3737 3738``-tpmdev backend,id=id[,options]`` 3739 The specific backend type will determine the applicable options. The 3740 ``-tpmdev`` option creates the TPM backend and requires a 3741 ``-device`` option that specifies the TPM frontend interface model. 3742 3743 Use ``-tpmdev help`` to print all available TPM backend types. 3744 3745The available backends are: 3746 3747``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3748 (Linux-host only) Enable access to the host's TPM using the 3749 passthrough driver. 3750 3751 ``path`` specifies the path to the host's TPM device, i.e., on a 3752 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3753 default ``/dev/tpm0`` is used. 3754 3755 ``cancel-path`` specifies the path to the host TPM device's sysfs 3756 entry allowing for cancellation of an ongoing TPM command. 3757 ``cancel-path`` is optional and by default QEMU will search for the 3758 sysfs entry to use. 3759 3760 Some notes about using the host's TPM with the passthrough driver: 3761 3762 The TPM device accessed by the passthrough driver must not be used 3763 by any other application on the host. 3764 3765 Since the host's firmware (BIOS/UEFI) has already initialized the 3766 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3767 the TPM again and may therefore not show a TPM-specific menu that 3768 would otherwise allow the user to configure the TPM, e.g., allow the 3769 user to enable/disable or activate/deactivate the TPM. Further, if 3770 TPM ownership is released from within a VM then the host's TPM will 3771 get disabled and deactivated. To enable and activate the TPM again 3772 afterwards, the host has to be rebooted and the user is required to 3773 enter the firmware's menu to enable and activate the TPM. If the TPM 3774 is left disabled and/or deactivated most TPM commands will fail. 3775 3776 To create a passthrough TPM use the following two options: 3777 3778 :: 3779 3780 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3781 3782 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3783 ``tpmdev=tpm0`` in the device option. 3784 3785``-tpmdev emulator,id=id,chardev=dev`` 3786 (Linux-host only) Enable access to a TPM emulator using Unix domain 3787 socket based chardev backend. 3788 3789 ``chardev`` specifies the unique ID of a character device backend 3790 that provides connection to the software TPM server. 3791 3792 To create a TPM emulator backend device with chardev socket backend: 3793 3794 :: 3795 3796 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3797ERST 3798 3799DEFHEADING() 3800 3801#endif 3802 3803DEFHEADING(Boot Image or Kernel specific:) 3804SRST 3805There are broadly 4 ways you can boot a system with QEMU. 3806 3807 - specify a firmware and let it control finding a kernel 3808 - specify a firmware and pass a hint to the kernel to boot 3809 - direct kernel image boot 3810 - manually load files into the guest's address space 3811 3812The third method is useful for quickly testing kernels but as there is 3813no firmware to pass configuration information to the kernel the 3814hardware must either be probeable, the kernel built for the exact 3815configuration or passed some configuration data (e.g. a DTB blob) 3816which tells the kernel what drivers it needs. This exact details are 3817often hardware specific. 3818 3819The final method is the most generic way of loading images into the 3820guest address space and used mostly for ``bare metal`` type 3821development where the reset vectors of the processor are taken into 3822account. 3823 3824ERST 3825 3826SRST 3827 3828For x86 machines and some other architectures ``-bios`` will generally 3829do the right thing with whatever it is given. For other machines the 3830more strict ``-pflash`` option needs an image that is sized for the 3831flash device for the given machine type. 3832 3833Please see the :ref:`system-targets-ref` section of the manual for 3834more detailed documentation. 3835 3836ERST 3837 3838DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3839 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3840SRST 3841``-bios file`` 3842 Set the filename for the BIOS. 3843ERST 3844 3845DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3846 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3847SRST 3848``-pflash file`` 3849 Use file as a parallel flash image. 3850ERST 3851 3852SRST 3853 3854The kernel options were designed to work with Linux kernels although 3855other things (like hypervisors) can be packaged up as a kernel 3856executable image. The exact format of a executable image is usually 3857architecture specific. 3858 3859The way in which the kernel is started (what address it is loaded at, 3860what if any information is passed to it via CPU registers, the state 3861of the hardware when it is started, and so on) is also architecture 3862specific. Typically it follows the specification laid down by the 3863Linux kernel for how kernels for that architecture must be started. 3864 3865ERST 3866 3867DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3868 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3869SRST 3870``-kernel bzImage`` 3871 Use bzImage as kernel image. The kernel can be either a Linux kernel 3872 or in multiboot format. 3873ERST 3874 3875DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3876 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3877SRST 3878``-append cmdline`` 3879 Use cmdline as kernel command line 3880ERST 3881 3882DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3883 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3884SRST 3885``-initrd file`` 3886 Use file as initial ram disk. 3887 3888``-initrd "file1 arg=foo,file2"`` 3889 This syntax is only available with multiboot. 3890 3891 Use file1 and file2 as modules and pass arg=foo as parameter to the 3892 first module. 3893ERST 3894 3895DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3896 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3897SRST 3898``-dtb file`` 3899 Use file as a device tree binary (dtb) image and pass it to the 3900 kernel on boot. 3901ERST 3902 3903SRST 3904 3905Finally you can also manually load images directly into the address 3906space of the guest. This is most useful for developers who already 3907know the layout of their guest and take care to ensure something sane 3908will happen when the reset vector executes. 3909 3910The generic loader can be invoked by using the loader device: 3911 3912``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3913 3914there is also the guest loader which operates in a similar way but 3915tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3916the guest image is: 3917 3918``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3919 3920ERST 3921 3922DEFHEADING() 3923 3924DEFHEADING(Debug/Expert options:) 3925 3926DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3927 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3928 " Policy for handling deprecated management interfaces\n" 3929 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3930 " Policy for handling unstable management interfaces\n", 3931 QEMU_ARCH_ALL) 3932SRST 3933``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3934 Set policy for handling deprecated management interfaces (experimental): 3935 3936 ``deprecated-input=accept`` (default) 3937 Accept deprecated commands and arguments 3938 ``deprecated-input=reject`` 3939 Reject deprecated commands and arguments 3940 ``deprecated-input=crash`` 3941 Crash on deprecated commands and arguments 3942 ``deprecated-output=accept`` (default) 3943 Emit deprecated command results and events 3944 ``deprecated-output=hide`` 3945 Suppress deprecated command results and events 3946 3947 Limitation: covers only syntactic aspects of QMP. 3948 3949``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3950 Set policy for handling unstable management interfaces (experimental): 3951 3952 ``unstable-input=accept`` (default) 3953 Accept unstable commands and arguments 3954 ``unstable-input=reject`` 3955 Reject unstable commands and arguments 3956 ``unstable-input=crash`` 3957 Crash on unstable commands and arguments 3958 ``unstable-output=accept`` (default) 3959 Emit unstable command results and events 3960 ``unstable-output=hide`` 3961 Suppress unstable command results and events 3962 3963 Limitation: covers only syntactic aspects of QMP. 3964ERST 3965 3966DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3967 "-fw_cfg [name=]<name>,file=<file>\n" 3968 " add named fw_cfg entry with contents from file\n" 3969 "-fw_cfg [name=]<name>,string=<str>\n" 3970 " add named fw_cfg entry with contents from string\n", 3971 QEMU_ARCH_ALL) 3972SRST 3973``-fw_cfg [name=]name,file=file`` 3974 Add named fw\_cfg entry with contents from file file. 3975 3976``-fw_cfg [name=]name,string=str`` 3977 Add named fw\_cfg entry with contents from string str. 3978 3979 The terminating NUL character of the contents of str will not be 3980 included as part of the fw\_cfg item data. To insert contents with 3981 embedded NUL characters, you have to use the file parameter. 3982 3983 The fw\_cfg entries are passed by QEMU through to the guest. 3984 3985 Example: 3986 3987 :: 3988 3989 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3990 3991 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3992 from ./my\_blob.bin. 3993ERST 3994 3995DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3996 "-serial dev redirect the serial port to char device 'dev'\n", 3997 QEMU_ARCH_ALL) 3998SRST 3999``-serial dev`` 4000 Redirect the virtual serial port to host character device dev. The 4001 default device is ``vc`` in graphical mode and ``stdio`` in non 4002 graphical mode. 4003 4004 This option can be used several times to simulate up to 4 serial 4005 ports. 4006 4007 Use ``-serial none`` to disable all serial ports. 4008 4009 Available character devices are: 4010 4011 ``vc[:WxH]`` 4012 Virtual console. Optionally, a width and height can be given in 4013 pixel with 4014 4015 :: 4016 4017 vc:800x600 4018 4019 It is also possible to specify width or height in characters: 4020 4021 :: 4022 4023 vc:80Cx24C 4024 4025 ``pty`` 4026 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4027 4028 ``none`` 4029 No device is allocated. 4030 4031 ``null`` 4032 void device 4033 4034 ``chardev:id`` 4035 Use a named character device defined with the ``-chardev`` 4036 option. 4037 4038 ``/dev/XXX`` 4039 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4040 port parameters are set according to the emulated ones. 4041 4042 ``/dev/parportN`` 4043 [Linux only, parallel port only] Use host parallel port N. 4044 Currently SPP and EPP parallel port features can be used. 4045 4046 ``file:filename`` 4047 Write output to filename. No character can be read. 4048 4049 ``stdio`` 4050 [Unix only] standard input/output 4051 4052 ``pipe:filename`` 4053 name pipe filename 4054 4055 ``COMn`` 4056 [Windows only] Use host serial port n 4057 4058 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4059 This implements UDP Net Console. When remote\_host or src\_ip 4060 are not specified they default to ``0.0.0.0``. When not using a 4061 specified src\_port a random port is automatically chosen. 4062 4063 If you just want a simple readonly console you can use 4064 ``netcat`` or ``nc``, by starting QEMU with: 4065 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4066 QEMU writes something to that port it will appear in the 4067 netconsole session. 4068 4069 If you plan to send characters back via netconsole or you want 4070 to stop and start QEMU a lot of times, you should have QEMU use 4071 the same source port each time by using something like ``-serial 4072 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4073 version of netcat which can listen to a TCP port and send and 4074 receive characters via udp. If you have a patched version of 4075 netcat which activates telnet remote echo and single char 4076 transfer, then you can use the following options to set up a 4077 netcat redirector to allow telnet on port 5555 to access the 4078 QEMU port. 4079 4080 ``QEMU Options:`` 4081 -serial udp::4555@:4556 4082 4083 ``netcat options:`` 4084 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4085 4086 ``telnet options:`` 4087 localhost 5555 4088 4089 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4090 The TCP Net Console has two modes of operation. It can send the 4091 serial I/O to a location or wait for a connection from a 4092 location. By default the TCP Net Console is sent to host at the 4093 port. If you use the ``server=on`` option QEMU will wait for a client 4094 socket application to connect to the port before continuing, 4095 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4096 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4097 option only applies if ``server=no`` is set, if the connection goes 4098 down it will attempt to reconnect at the given interval. If host 4099 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4100 time is accepted. You can use ``telnet=on`` to connect to the 4101 corresponding character device. 4102 4103 ``Example to send tcp console to 192.168.0.2 port 4444`` 4104 -serial tcp:192.168.0.2:4444 4105 4106 ``Example to listen and wait on port 4444 for connection`` 4107 -serial tcp::4444,server=on 4108 4109 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4110 -serial tcp:192.168.0.100:4444,server=on,wait=off 4111 4112 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4113 The telnet protocol is used instead of raw tcp sockets. The 4114 options work the same as if you had specified ``-serial tcp``. 4115 The difference is that the port acts like a telnet server or 4116 client using telnet option negotiation. This will also allow you 4117 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4118 supports sending the break sequence. Typically in unix telnet 4119 you do it with Control-] and then type "send break" followed by 4120 pressing the enter key. 4121 4122 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4123 The WebSocket protocol is used instead of raw tcp socket. The 4124 port acts as a WebSocket server. Client mode is not supported. 4125 4126 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4127 A unix domain socket is used instead of a tcp socket. The option 4128 works the same as if you had specified ``-serial tcp`` except 4129 the unix domain socket path is used for connections. 4130 4131 ``mon:dev_string`` 4132 This is a special option to allow the monitor to be multiplexed 4133 onto another serial port. The monitor is accessed with key 4134 sequence of Control-a and then pressing c. dev\_string should be 4135 any one of the serial devices specified above. An example to 4136 multiplex the monitor onto a telnet server listening on port 4137 4444 would be: 4138 4139 ``-serial mon:telnet::4444,server=on,wait=off`` 4140 4141 When the monitor is multiplexed to stdio in this way, Ctrl+C 4142 will not terminate QEMU any more but will be passed to the guest 4143 instead. 4144 4145 ``braille`` 4146 Braille device. This will use BrlAPI to display the braille 4147 output on a real or fake device. 4148 4149 ``msmouse`` 4150 Three button serial mouse. Configure the guest to use Microsoft 4151 protocol. 4152ERST 4153 4154DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4155 "-parallel dev redirect the parallel port to char device 'dev'\n", 4156 QEMU_ARCH_ALL) 4157SRST 4158``-parallel dev`` 4159 Redirect the virtual parallel port to host device dev (same devices 4160 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4161 to use hardware devices connected on the corresponding host parallel 4162 port. 4163 4164 This option can be used several times to simulate up to 3 parallel 4165 ports. 4166 4167 Use ``-parallel none`` to disable all parallel ports. 4168ERST 4169 4170DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4171 "-monitor dev redirect the monitor to char device 'dev'\n", 4172 QEMU_ARCH_ALL) 4173SRST 4174``-monitor dev`` 4175 Redirect the monitor to host device dev (same devices as the serial 4176 port). The default device is ``vc`` in graphical mode and ``stdio`` 4177 in non graphical mode. Use ``-monitor none`` to disable the default 4178 monitor. 4179ERST 4180DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4181 "-qmp dev like -monitor but opens in 'control' mode\n", 4182 QEMU_ARCH_ALL) 4183SRST 4184``-qmp dev`` 4185 Like ``-monitor`` but opens in 'control' mode. For example, to make 4186 QMP available on localhost port 4444:: 4187 4188 -qmp tcp:localhost:4444,server=on,wait=off 4189 4190 Not all options are configurable via this syntax; for maximum 4191 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4192 4193ERST 4194DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4195 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4196 QEMU_ARCH_ALL) 4197SRST 4198``-qmp-pretty dev`` 4199 Like ``-qmp`` but uses pretty JSON formatting. 4200ERST 4201 4202DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4203 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4204SRST 4205``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4206 Set up a monitor connected to the chardev ``name``. 4207 QEMU supports two monitors: the Human Monitor Protocol 4208 (HMP; for human interaction), and the QEMU Monitor Protocol 4209 (QMP; a JSON RPC-style protocol). 4210 The default is HMP; ``mode=control`` selects QMP instead. 4211 ``pretty`` is only valid when ``mode=control``, 4212 turning on JSON pretty printing to ease 4213 human reading and debugging. 4214 4215 For example:: 4216 4217 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4218 -mon chardev=mon1,mode=control,pretty=on 4219 4220 enables the QMP monitor on localhost port 4444 with pretty-printing. 4221ERST 4222 4223DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4224 "-debugcon dev redirect the debug console to char device 'dev'\n", 4225 QEMU_ARCH_ALL) 4226SRST 4227``-debugcon dev`` 4228 Redirect the debug console to host device dev (same devices as the 4229 serial port). The debug console is an I/O port which is typically 4230 port 0xe9; writing to that I/O port sends output to this device. The 4231 default device is ``vc`` in graphical mode and ``stdio`` in non 4232 graphical mode. 4233ERST 4234 4235DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4236 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4237SRST 4238``-pidfile file`` 4239 Store the QEMU process PID in file. It is useful if you launch QEMU 4240 from a script. 4241ERST 4242 4243DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4244 "-singlestep deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL) 4245SRST 4246``-singlestep`` 4247 This is a deprecated synonym for the TCG accelerator property 4248 ``one-insn-per-tb``. 4249ERST 4250 4251DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4252 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4253 QEMU_ARCH_ALL) 4254SRST 4255``--preconfig`` 4256 Pause QEMU for interactive configuration before the machine is 4257 created, which allows querying and configuring properties that will 4258 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4259 exit the preconfig state and move to the next state (i.e. run guest 4260 if -S isn't used or pause the second time if -S is used). This 4261 option is experimental. 4262ERST 4263 4264DEF("S", 0, QEMU_OPTION_S, \ 4265 "-S freeze CPU at startup (use 'c' to start execution)\n", 4266 QEMU_ARCH_ALL) 4267SRST 4268``-S`` 4269 Do not start CPU at startup (you must type 'c' in the monitor). 4270ERST 4271 4272DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4273 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4274 " run qemu with overcommit hints\n" 4275 " mem-lock=on|off controls memory lock support (default: off)\n" 4276 " cpu-pm=on|off controls cpu power management (default: off)\n", 4277 QEMU_ARCH_ALL) 4278SRST 4279``-overcommit mem-lock=on|off`` 4280 \ 4281``-overcommit cpu-pm=on|off`` 4282 Run qemu with hints about host resource overcommit. The default is 4283 to assume that host overcommits all resources. 4284 4285 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4286 (disabled by default). This works when host memory is not 4287 overcommitted and reduces the worst-case latency for guest. 4288 4289 Guest ability to manage power state of host cpus (increasing latency 4290 for other processes on the same host cpu, but decreasing latency for 4291 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4292 works best when host CPU is not overcommitted. When used, host 4293 estimates of CPU cycle and power utilization will be incorrect, not 4294 taking into account guest idle time. 4295ERST 4296 4297DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4298 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4299 " the guest without waiting for gdb to connect; use -S too\n" 4300 " if you want it to not start execution.)\n", 4301 QEMU_ARCH_ALL) 4302SRST 4303``-gdb dev`` 4304 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4305 in the System Emulation Users Guide). Note that this option does not pause QEMU 4306 execution -- if you want QEMU to not start the guest until you 4307 connect with gdb and issue a ``continue`` command, you will need to 4308 also pass the ``-S`` option to QEMU. 4309 4310 The most usual configuration is to listen on a local TCP socket:: 4311 4312 -gdb tcp::3117 4313 4314 but you can specify other backends; UDP, pseudo TTY, or even stdio 4315 are all reasonable use cases. For example, a stdio connection 4316 allows you to start QEMU from within gdb and establish the 4317 connection via a pipe: 4318 4319 .. parsed-literal:: 4320 4321 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4322ERST 4323 4324DEF("s", 0, QEMU_OPTION_s, \ 4325 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4326 QEMU_ARCH_ALL) 4327SRST 4328``-s`` 4329 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4330 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4331ERST 4332 4333DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4334 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4335 QEMU_ARCH_ALL) 4336SRST 4337``-d item1[,...]`` 4338 Enable logging of specified items. Use '-d help' for a list of log 4339 items. 4340ERST 4341 4342DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4343 "-D logfile output log to logfile (default stderr)\n", 4344 QEMU_ARCH_ALL) 4345SRST 4346``-D logfile`` 4347 Output log in logfile instead of to stderr 4348ERST 4349 4350DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4351 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4352 QEMU_ARCH_ALL) 4353SRST 4354``-dfilter range1[,...]`` 4355 Filter debug output to that relevant to a range of target addresses. 4356 The filter spec can be either start+size, start-size or start..end 4357 where start end and size are the addresses and sizes required. For 4358 example: 4359 4360 :: 4361 4362 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4363 4364 Will dump output for any code in the 0x1000 sized block starting at 4365 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4366 another 0x1000 sized block starting at 0xffffffc00005f000. 4367ERST 4368 4369DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4370 "-seed number seed the pseudo-random number generator\n", 4371 QEMU_ARCH_ALL) 4372SRST 4373``-seed number`` 4374 Force the guest to use a deterministic pseudo-random number 4375 generator, seeded with number. This does not affect crypto routines 4376 within the host. 4377ERST 4378 4379DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4380 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4381 QEMU_ARCH_ALL) 4382SRST 4383``-L path`` 4384 Set the directory for the BIOS, VGA BIOS and keymaps. 4385 4386 To list all the data directories, use ``-L help``. 4387ERST 4388 4389DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4390 "-enable-kvm enable KVM full virtualization support\n", 4391 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4392 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4393SRST 4394``-enable-kvm`` 4395 Enable KVM full virtualization support. This option is only 4396 available if KVM support is enabled when compiling. 4397ERST 4398 4399DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4400 "-xen-domid id specify xen guest domain id\n", 4401 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4402DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4403 "-xen-attach attach to existing xen domain\n" 4404 " libxl will use this when starting QEMU\n", 4405 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4406DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4407 "-xen-domid-restrict restrict set of available xen operations\n" 4408 " to specified domain id. (Does not affect\n" 4409 " xenpv machine type).\n", 4410 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4411SRST 4412``-xen-domid id`` 4413 Specify xen guest domain id (XEN only). 4414 4415``-xen-attach`` 4416 Attach to existing xen domain. libxl will use this when starting 4417 QEMU (XEN only). Restrict set of available xen operations to 4418 specified domain id (XEN only). 4419ERST 4420 4421DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4422 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4423SRST 4424``-no-reboot`` 4425 Exit instead of rebooting. 4426ERST 4427 4428DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4429 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4430SRST 4431``-no-shutdown`` 4432 Don't exit QEMU on guest shutdown, but instead only stop the 4433 emulation. This allows for instance switching to monitor to commit 4434 changes to the disk image. 4435ERST 4436 4437DEF("action", HAS_ARG, QEMU_OPTION_action, 4438 "-action reboot=reset|shutdown\n" 4439 " action when guest reboots [default=reset]\n" 4440 "-action shutdown=poweroff|pause\n" 4441 " action when guest shuts down [default=poweroff]\n" 4442 "-action panic=pause|shutdown|exit-failure|none\n" 4443 " action when guest panics [default=shutdown]\n" 4444 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4445 " action when watchdog fires [default=reset]\n", 4446 QEMU_ARCH_ALL) 4447SRST 4448``-action event=action`` 4449 The action parameter serves to modify QEMU's default behavior when 4450 certain guest events occur. It provides a generic method for specifying the 4451 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4452 parameters. 4453 4454 Examples: 4455 4456 ``-action panic=none`` 4457 ``-action reboot=shutdown,shutdown=pause`` 4458 ``-device i6300esb -action watchdog=pause`` 4459 4460ERST 4461 4462DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4463 "-loadvm [tag|id]\n" \ 4464 " start right away with a saved state (loadvm in monitor)\n", 4465 QEMU_ARCH_ALL) 4466SRST 4467``-loadvm file`` 4468 Start right away with a saved state (``loadvm`` in monitor) 4469ERST 4470 4471#ifndef _WIN32 4472DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4473 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4474#endif 4475SRST 4476``-daemonize`` 4477 Daemonize the QEMU process after initialization. QEMU will not 4478 detach from standard IO until it is ready to receive connections on 4479 any of its devices. This option is a useful way for external 4480 programs to launch QEMU without having to cope with initialization 4481 race conditions. 4482ERST 4483 4484DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4485 "-option-rom rom load a file, rom, into the option ROM space\n", 4486 QEMU_ARCH_ALL) 4487SRST 4488``-option-rom file`` 4489 Load the contents of file as an option ROM. This option is useful to 4490 load things like EtherBoot. 4491ERST 4492 4493DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4494 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4495 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4496 QEMU_ARCH_ALL) 4497 4498SRST 4499``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4500 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4501 the current UTC or local time, respectively. ``localtime`` is 4502 required for correct date in MS-DOS or Windows. To start at a 4503 specific point in time, provide datetime in the format 4504 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4505 4506 By default the RTC is driven by the host system time. This allows 4507 using of the RTC as accurate reference clock inside the guest, 4508 specifically if the host time is smoothly following an accurate 4509 external reference clock, e.g. via NTP. If you want to isolate the 4510 guest time from the host, you can set ``clock`` to ``rt`` instead, 4511 which provides a host monotonic clock if host support it. To even 4512 prevent the RTC from progressing during suspension, you can set 4513 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4514 recommended especially in icount mode in order to preserve 4515 determinism; however, note that in icount mode the speed of the 4516 virtual clock is variable and can in general differ from the host 4517 clock. 4518 4519 Enable ``driftfix`` (i386 targets only) if you experience time drift 4520 problems, specifically with Windows' ACPI HAL. This option will try 4521 to figure out how many timer interrupts were not processed by the 4522 Windows guest and will re-inject them. 4523ERST 4524 4525DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4526 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4527 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4528 " instruction, enable aligning the host and virtual clocks\n" \ 4529 " or disable real time cpu sleeping, and optionally enable\n" \ 4530 " record-and-replay mode\n", QEMU_ARCH_ALL) 4531SRST 4532``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4533 Enable virtual instruction counter. The virtual cpu will execute one 4534 instruction every 2^N ns of virtual time. If ``auto`` is specified 4535 then the virtual cpu speed will be automatically adjusted to keep 4536 virtual time within a few seconds of real time. 4537 4538 Note that while this option can give deterministic behavior, it does 4539 not provide cycle accurate emulation. Modern CPUs contain 4540 superscalar out of order cores with complex cache hierarchies. The 4541 number of instructions executed often has little or no correlation 4542 with actual performance. 4543 4544 When the virtual cpu is sleeping, the virtual time will advance at 4545 default speed unless ``sleep=on`` is specified. With 4546 ``sleep=on``, the virtual time will jump to the next timer 4547 deadline instantly whenever the virtual cpu goes to sleep mode and 4548 will not advance if no timer is enabled. This behavior gives 4549 deterministic execution times from the guest point of view. 4550 The default if icount is enabled is ``sleep=off``. 4551 ``sleep=on`` cannot be used together with either ``shift=auto`` 4552 or ``align=on``. 4553 4554 ``align=on`` will activate the delay algorithm which will try to 4555 synchronise the host clock and the virtual clock. The goal is to 4556 have a guest running at the real frequency imposed by the shift 4557 option. Whenever the guest clock is behind the host clock and if 4558 ``align=on`` is specified then we print a message to the user to 4559 inform about the delay. Currently this option does not work when 4560 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4561 shift values for which the guest clock runs ahead of the host clock. 4562 Typically this happens when the shift value is high (how high 4563 depends on the host machine). The default if icount is enabled 4564 is ``align=off``. 4565 4566 When the ``rr`` option is specified deterministic record/replay is 4567 enabled. The ``rrfile=`` option must also be provided to 4568 specify the path to the replay log. In record mode data is written 4569 to this file, and in replay mode it is read back. 4570 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4571 name. In record mode, a new VM snapshot with the given name is created 4572 at the start of execution recording. In replay mode this option 4573 specifies the snapshot name used to load the initial VM state. 4574ERST 4575 4576DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4577 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4578 " action when watchdog fires [default=reset]\n", 4579 QEMU_ARCH_ALL) 4580SRST 4581``-watchdog-action action`` 4582 The action controls what QEMU will do when the watchdog timer 4583 expires. The default is ``reset`` (forcefully reset the guest). 4584 Other possible actions are: ``shutdown`` (attempt to gracefully 4585 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4586 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4587 guest), ``debug`` (print a debug message and continue), or ``none`` 4588 (do nothing). 4589 4590 Note that the ``shutdown`` action requires that the guest responds 4591 to ACPI signals, which it may not be able to do in the sort of 4592 situations where the watchdog would have expired, and thus 4593 ``-watchdog-action shutdown`` is not recommended for production use. 4594 4595 Examples: 4596 4597 ``-device i6300esb -watchdog-action pause`` 4598 4599ERST 4600 4601DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4602 "-echr chr set terminal escape character instead of ctrl-a\n", 4603 QEMU_ARCH_ALL) 4604SRST 4605``-echr numeric_ascii_value`` 4606 Change the escape character used for switching to the monitor when 4607 using monitor and serial sharing. The default is ``0x01`` when using 4608 the ``-nographic`` option. ``0x01`` is equal to pressing 4609 ``Control-a``. You can select a different character from the ascii 4610 control keys where 1 through 26 map to Control-a through Control-z. 4611 For instance you could use the either of the following to change the 4612 escape character to Control-t. 4613 4614 ``-echr 0x14``; \ ``-echr 20`` 4615 4616ERST 4617 4618DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4619 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4620 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4621 "-incoming unix:socketpath\n" \ 4622 " prepare for incoming migration, listen on\n" \ 4623 " specified protocol and socket address\n" \ 4624 "-incoming fd:fd\n" \ 4625 "-incoming exec:cmdline\n" \ 4626 " accept incoming migration on given file descriptor\n" \ 4627 " or from given external command\n" \ 4628 "-incoming defer\n" \ 4629 " wait for the URI to be specified via migrate_incoming\n", 4630 QEMU_ARCH_ALL) 4631SRST 4632``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4633 \ 4634``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4635 Prepare for incoming migration, listen on a given tcp port. 4636 4637``-incoming unix:socketpath`` 4638 Prepare for incoming migration, listen on a given unix socket. 4639 4640``-incoming fd:fd`` 4641 Accept incoming migration from a given filedescriptor. 4642 4643``-incoming exec:cmdline`` 4644 Accept incoming migration as an output from specified external 4645 command. 4646 4647``-incoming defer`` 4648 Wait for the URI to be specified via migrate\_incoming. The monitor 4649 can be used to change settings (such as migration parameters) prior 4650 to issuing the migrate\_incoming to allow the migration to begin. 4651ERST 4652 4653DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4654 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4655SRST 4656``-only-migratable`` 4657 Only allow migratable devices. Devices will not be allowed to enter 4658 an unmigratable state. 4659ERST 4660 4661DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4662 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4663SRST 4664``-nodefaults`` 4665 Don't create default devices. Normally, QEMU sets the default 4666 devices like serial port, parallel port, virtual console, monitor 4667 device, VGA adapter, floppy and CD-ROM drive and others. The 4668 ``-nodefaults`` option will disable all those default devices. 4669ERST 4670 4671#ifndef _WIN32 4672DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4673 "-chroot dir chroot to dir just before starting the VM\n", 4674 QEMU_ARCH_ALL) 4675#endif 4676SRST 4677``-chroot dir`` 4678 Immediately before starting guest execution, chroot to the specified 4679 directory. Especially useful in combination with -runas. 4680ERST 4681 4682#ifndef _WIN32 4683DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4684 "-runas user change to user id user just before starting the VM\n" \ 4685 " user can be numeric uid:gid instead\n", 4686 QEMU_ARCH_ALL) 4687#endif 4688SRST 4689``-runas user`` 4690 Immediately before starting guest execution, drop root privileges, 4691 switching to the specified user. 4692ERST 4693 4694DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4695 "-prom-env variable=value\n" 4696 " set OpenBIOS nvram variables\n", 4697 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4698SRST 4699``-prom-env variable=value`` 4700 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4701 4702 :: 4703 4704 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4705 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4706 4707 :: 4708 4709 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4710 -prom-env 'boot-device=hd:2,\yaboot' \ 4711 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4712ERST 4713DEF("semihosting", 0, QEMU_OPTION_semihosting, 4714 "-semihosting semihosting mode\n", 4715 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4716 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4717SRST 4718``-semihosting`` 4719 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4720 4721 .. warning:: 4722 Note that this allows guest direct access to the host filesystem, so 4723 should only be used with a trusted guest OS. 4724 4725 See the -semihosting-config option documentation for further 4726 information about the facilities this enables. 4727ERST 4728DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4729 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4730 " semihosting configuration\n", 4731QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4732QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4733SRST 4734``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4735 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4736 only). 4737 4738 .. warning:: 4739 Note that this allows guest direct access to the host filesystem, so 4740 should only be used with a trusted guest OS. 4741 4742 ``target=native|gdb|auto`` 4743 Defines where the semihosting calls will be addressed, to QEMU 4744 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4745 means ``gdb`` during debug sessions and ``native`` otherwise. 4746 4747 ``chardev=str1`` 4748 Send the output to a chardev backend output for native or auto 4749 output when not in gdb 4750 4751 ``userspace=on|off`` 4752 Allows code running in guest userspace to access the semihosting 4753 interface. The default is that only privileged guest code can 4754 make semihosting calls. Note that setting ``userspace=on`` should 4755 only be used if all guest code is trusted (for example, in 4756 bare-metal test case code). 4757 4758 ``arg=str1,arg=str2,...`` 4759 Allows the user to pass input arguments, and can be used 4760 multiple times to build up a list. The old-style 4761 ``-kernel``/``-append`` method of passing a command line is 4762 still supported for backward compatibility. If both the 4763 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4764 specified, the former is passed to semihosting as it always 4765 takes precedence. 4766ERST 4767DEF("old-param", 0, QEMU_OPTION_old_param, 4768 "-old-param old param mode\n", QEMU_ARCH_ARM) 4769SRST 4770``-old-param`` 4771 Old param mode (ARM only). 4772ERST 4773 4774DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4775 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4776 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4777 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4778 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4779 " by the kernel, but typically no longer used by modern\n" \ 4780 " C library implementations.\n" \ 4781 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4782 " to elevate privileges using set*uid|gid system calls.\n" \ 4783 " The value 'children' will deny set*uid|gid system calls for\n" \ 4784 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4785 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4786 " blocking *fork and execve\n" \ 4787 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4788 QEMU_ARCH_ALL) 4789SRST 4790``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4791 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4792 filtering and 'off' will disable it. The default is 'off'. 4793 4794 ``obsolete=string`` 4795 Enable Obsolete system calls 4796 4797 ``elevateprivileges=string`` 4798 Disable set\*uid\|gid system calls 4799 4800 ``spawn=string`` 4801 Disable \*fork and execve 4802 4803 ``resourcecontrol=string`` 4804 Disable process affinity and schedular priority 4805ERST 4806 4807DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4808 "-readconfig <file>\n" 4809 " read config file\n", QEMU_ARCH_ALL) 4810SRST 4811``-readconfig file`` 4812 Read device configuration from file. This approach is useful when 4813 you want to spawn QEMU process with many command line options but 4814 you don't want to exceed the command line character limit. 4815ERST 4816 4817DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4818 "-no-user-config\n" 4819 " do not load default user-provided config files at startup\n", 4820 QEMU_ARCH_ALL) 4821SRST 4822``-no-user-config`` 4823 The ``-no-user-config`` option makes QEMU not load any of the 4824 user-provided config files on sysconfdir. 4825ERST 4826 4827DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4828 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4829 " specify tracing options\n", 4830 QEMU_ARCH_ALL) 4831SRST 4832``-trace [[enable=]pattern][,events=file][,file=file]`` 4833 .. include:: ../qemu-option-trace.rst.inc 4834 4835ERST 4836DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4837 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4838 " load a plugin\n", 4839 QEMU_ARCH_ALL) 4840SRST 4841``-plugin file=file[,argname=argvalue]`` 4842 Load a plugin. 4843 4844 ``file=file`` 4845 Load the given plugin from a shared library file. 4846 4847 ``argname=argvalue`` 4848 Argument passed to the plugin. (Can be given multiple times.) 4849ERST 4850 4851HXCOMM Internal use 4852DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4853DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4854 4855#ifdef __linux__ 4856DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4857 "-async-teardown enable asynchronous teardown\n", 4858 QEMU_ARCH_ALL) 4859SRST 4860``-async-teardown`` 4861 This option is deprecated and should no longer be used. The new option 4862 ``-run-with async-teardown=on`` is a replacement. 4863ERST 4864DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4865 "-run-with async-teardown[=on|off]\n" 4866 " misc QEMU process lifecycle options\n" 4867 " async-teardown=on enables asynchronous teardown\n", 4868 QEMU_ARCH_ALL) 4869SRST 4870``-run-with`` 4871 Set QEMU process lifecycle options. 4872 4873 ``async-teardown=on`` enables asynchronous teardown. A new process called 4874 "cleanup/<QEMU_PID>" will be created at startup sharing the address 4875 space with the main QEMU process, using clone. It will wait for the 4876 main QEMU process to terminate completely, and then exit. This allows 4877 QEMU to terminate very quickly even if the guest was huge, leaving the 4878 teardown of the address space to the cleanup process. Since the cleanup 4879 process shares the same cgroups as the main QEMU process, accounting is 4880 performed correctly. This only works if the cleanup process is not 4881 forcefully killed with SIGKILL before the main QEMU process has 4882 terminated completely. 4883ERST 4884#endif 4885 4886DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4887 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4888 " control error message format\n" 4889 " timestamp=on enables timestamps (default: off)\n" 4890 " guest-name=on enables guest name prefix but only if\n" 4891 " -name guest option is set (default: off)\n", 4892 QEMU_ARCH_ALL) 4893SRST 4894``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4895 Control error message format. 4896 4897 ``timestamp=on|off`` 4898 Prefix messages with a timestamp. Default is off. 4899 4900 ``guest-name=on|off`` 4901 Prefix messages with guest name but only if -name guest option is set 4902 otherwise the option is ignored. Default is off. 4903ERST 4904 4905DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4906 "-dump-vmstate <file>\n" 4907 " Output vmstate information in JSON format to file.\n" 4908 " Use the scripts/vmstate-static-checker.py file to\n" 4909 " check for possible regressions in migration code\n" 4910 " by comparing two such vmstate dumps.\n", 4911 QEMU_ARCH_ALL) 4912SRST 4913``-dump-vmstate file`` 4914 Dump json-encoded vmstate information for current machine type to 4915 file in file 4916ERST 4917 4918DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4919 "-enable-sync-profile\n" 4920 " enable synchronization profiling\n", 4921 QEMU_ARCH_ALL) 4922SRST 4923``-enable-sync-profile`` 4924 Enable synchronization profiling. 4925ERST 4926 4927#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 4928DEF("perfmap", 0, QEMU_OPTION_perfmap, 4929 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 4930 QEMU_ARCH_ALL) 4931SRST 4932``-perfmap`` 4933 Generate a map file for Linux perf tools that will allow basic profiling 4934 information to be broken down into basic blocks. 4935ERST 4936 4937DEF("jitdump", 0, QEMU_OPTION_jitdump, 4938 "-jitdump generate a jit-${pid}.dump file for perf\n", 4939 QEMU_ARCH_ALL) 4940SRST 4941``-jitdump`` 4942 Generate a dump file for Linux perf tools that maps basic blocks to symbol 4943 names, line numbers and JITted code. 4944ERST 4945#endif 4946 4947DEFHEADING() 4948 4949DEFHEADING(Generic object creation:) 4950 4951DEF("object", HAS_ARG, QEMU_OPTION_object, 4952 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4953 " create a new object of type TYPENAME setting properties\n" 4954 " in the order they are specified. Note that the 'id'\n" 4955 " property must be set. These objects are placed in the\n" 4956 " '/objects' path.\n", 4957 QEMU_ARCH_ALL) 4958SRST 4959``-object typename[,prop1=value1,...]`` 4960 Create a new object of type typename setting properties in the order 4961 they are specified. Note that the 'id' property must be set. These 4962 objects are placed in the '/objects' path. 4963 4964 ``-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`` 4965 Creates a memory file backend object, which can be used to back 4966 the guest RAM with huge pages. 4967 4968 The ``id`` parameter is a unique ID that will be used to 4969 reference this memory region in other parameters, e.g. ``-numa``, 4970 ``-device nvdimm``, etc. 4971 4972 The ``size`` option provides the size of the memory region, and 4973 accepts common suffixes, e.g. ``500M``. 4974 4975 The ``mem-path`` provides the path to either a shared memory or 4976 huge page filesystem mount. 4977 4978 The ``share`` boolean option determines whether the memory 4979 region is marked as private to QEMU, or shared. The latter 4980 allows a co-operating external process to access the QEMU memory 4981 region. 4982 4983 The ``share`` is also required for pvrdma devices due to 4984 limitations in the RDMA API provided by Linux. 4985 4986 Setting share=on might affect the ability to configure NUMA 4987 bindings for the memory backend under some circumstances, see 4988 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4989 source tree for additional details. 4990 4991 Setting the ``discard-data`` boolean option to on indicates that 4992 file contents can be destroyed when QEMU exits, to avoid 4993 unnecessarily flushing data to the backing file. Note that 4994 ``discard-data`` is only an optimization, and QEMU might not 4995 discard file contents if it aborts unexpectedly or is terminated 4996 using SIGKILL. 4997 4998 The ``merge`` boolean option enables memory merge, also known as 4999 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5000 the pages for memory deduplication. 5001 5002 Setting the ``dump`` boolean option to off excludes the memory 5003 from core dumps. This feature is also known as MADV\_DONTDUMP. 5004 5005 The ``prealloc`` boolean option enables memory preallocation. 5006 5007 The ``host-nodes`` option binds the memory range to a list of 5008 NUMA host nodes. 5009 5010 The ``policy`` option sets the NUMA policy to one of the 5011 following values: 5012 5013 ``default`` 5014 default host policy 5015 5016 ``preferred`` 5017 prefer the given host node list for allocation 5018 5019 ``bind`` 5020 restrict memory allocation to the given host node list 5021 5022 ``interleave`` 5023 interleave memory allocations across the given host node 5024 list 5025 5026 The ``align`` option specifies the base address alignment when 5027 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5028 ``2M``. Some backend store specified by ``mem-path`` requires an 5029 alignment different than the default one used by QEMU, eg the 5030 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5031 such cases, users can specify the required alignment via this 5032 option. 5033 5034 The ``offset`` option specifies the offset into the target file 5035 that the region starts at. You can use this parameter to back 5036 multiple regions with a single file. 5037 5038 The ``pmem`` option specifies whether the backing file specified 5039 by ``mem-path`` is in host persistent memory that can be 5040 accessed using the SNIA NVM programming model (e.g. Intel 5041 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5042 operations to guarantee the persistence of its own writes to 5043 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5044 migration). Also, we will map the backend-file with MAP\_SYNC 5045 flag, which ensures the file metadata is in sync for 5046 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5047 requires support from both the host kernel (since Linux kernel 5048 4.15) and the filesystem of ``mem-path`` mounted with DAX 5049 option. 5050 5051 The ``readonly`` option specifies whether the backing file is opened 5052 read-only or read-write (default). 5053 5054 ``-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`` 5055 Creates a memory backend object, which can be used to back the 5056 guest RAM. Memory backend objects offer more control than the 5057 ``-m`` option that is traditionally used to define guest RAM. 5058 Please refer to ``memory-backend-file`` for a description of the 5059 options. 5060 5061 ``-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`` 5062 Creates an anonymous memory file backend object, which allows 5063 QEMU to share the memory with an external process (e.g. when 5064 using vhost-user). The memory is allocated with memfd and 5065 optional sealing. (Linux only) 5066 5067 The ``seal`` option creates a sealed-file, that will block 5068 further resizing the memory ('on' by default). 5069 5070 The ``hugetlb`` option specify the file to be created resides in 5071 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5072 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5073 the hugetlb page size on systems that support multiple hugetlb 5074 page sizes (it must be a power of 2 value supported by the 5075 system). 5076 5077 In some versions of Linux, the ``hugetlb`` option is 5078 incompatible with the ``seal`` option (requires at least Linux 5079 4.16). 5080 5081 Please refer to ``memory-backend-file`` for a description of the 5082 other options. 5083 5084 The ``share`` boolean option is on by default with memfd. 5085 5086 ``-object rng-builtin,id=id`` 5087 Creates a random number generator backend which obtains entropy 5088 from QEMU builtin functions. The ``id`` parameter is a unique ID 5089 that will be used to reference this entropy backend from the 5090 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5091 uses this RNG backend. 5092 5093 ``-object rng-random,id=id,filename=/dev/random`` 5094 Creates a random number generator backend which obtains entropy 5095 from a device on the host. The ``id`` parameter is a unique ID 5096 that will be used to reference this entropy backend from the 5097 ``virtio-rng`` device. The ``filename`` parameter specifies 5098 which file to obtain entropy from and if omitted defaults to 5099 ``/dev/urandom``. 5100 5101 ``-object rng-egd,id=id,chardev=chardevid`` 5102 Creates a random number generator backend which obtains entropy 5103 from an external daemon running on the host. The ``id`` 5104 parameter is a unique ID that will be used to reference this 5105 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5106 parameter is the unique ID of a character device backend that 5107 provides the connection to the RNG daemon. 5108 5109 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5110 Creates a TLS anonymous credentials object, which can be used to 5111 provide TLS support on network backends. The ``id`` parameter is 5112 a unique ID which network backends will use to access the 5113 credentials. The ``endpoint`` is either ``server`` or ``client`` 5114 depending on whether the QEMU network backend that uses the 5115 credentials will be acting as a client or as a server. If 5116 ``verify-peer`` is enabled (the default) then once the handshake 5117 is completed, the peer credentials will be verified, though this 5118 is a no-op for anonymous credentials. 5119 5120 The dir parameter tells QEMU where to find the credential files. 5121 For server endpoints, this directory may contain a file 5122 dh-params.pem providing diffie-hellman parameters to use for the 5123 TLS server. If the file is missing, QEMU will generate a set of 5124 DH parameters at startup. This is a computationally expensive 5125 operation that consumes random pool entropy, so it is 5126 recommended that a persistent set of parameters be generated 5127 upfront and saved. 5128 5129 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5130 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5131 can be used to provide TLS support on network backends. The 5132 ``id`` parameter is a unique ID which network backends will use 5133 to access the credentials. The ``endpoint`` is either ``server`` 5134 or ``client`` depending on whether the QEMU network backend that 5135 uses the credentials will be acting as a client or as a server. 5136 For clients only, ``username`` is the username which will be 5137 sent to the server. If omitted it defaults to "qemu". 5138 5139 The dir parameter tells QEMU where to find the keys file. It is 5140 called "dir/keys.psk" and contains "username:key" pairs. This 5141 file can most easily be created using the GnuTLS ``psktool`` 5142 program. 5143 5144 For server endpoints, dir may also contain a file dh-params.pem 5145 providing diffie-hellman parameters to use for the TLS server. 5146 If the file is missing, QEMU will generate a set of DH 5147 parameters at startup. This is a computationally expensive 5148 operation that consumes random pool entropy, so it is 5149 recommended that a persistent set of parameters be generated up 5150 front and saved. 5151 5152 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5153 Creates a TLS anonymous credentials object, which can be used to 5154 provide TLS support on network backends. The ``id`` parameter is 5155 a unique ID which network backends will use to access the 5156 credentials. The ``endpoint`` is either ``server`` or ``client`` 5157 depending on whether the QEMU network backend that uses the 5158 credentials will be acting as a client or as a server. If 5159 ``verify-peer`` is enabled (the default) then once the handshake 5160 is completed, the peer credentials will be verified. With x509 5161 certificates, this implies that the clients must be provided 5162 with valid client certificates too. 5163 5164 The dir parameter tells QEMU where to find the credential files. 5165 For server endpoints, this directory may contain a file 5166 dh-params.pem providing diffie-hellman parameters to use for the 5167 TLS server. If the file is missing, QEMU will generate a set of 5168 DH parameters at startup. This is a computationally expensive 5169 operation that consumes random pool entropy, so it is 5170 recommended that a persistent set of parameters be generated 5171 upfront and saved. 5172 5173 For x509 certificate credentials the directory will contain 5174 further files providing the x509 certificates. The certificates 5175 must be stored in PEM format, in filenames ca-cert.pem, 5176 ca-crl.pem (optional), server-cert.pem (only servers), 5177 server-key.pem (only servers), client-cert.pem (only clients), 5178 and client-key.pem (only clients). 5179 5180 For the server-key.pem and client-key.pem files which contain 5181 sensitive private keys, it is possible to use an encrypted 5182 version by providing the passwordid parameter. This provides the 5183 ID of a previously created ``secret`` object containing the 5184 password for decryption. 5185 5186 The priority parameter allows to override the global default 5187 priority used by gnutls. This can be useful if the system 5188 administrator needs to use a weaker set of crypto priorities for 5189 QEMU without potentially forcing the weakness onto all 5190 applications. Or conversely if one wants wants a stronger 5191 default for QEMU than for all other applications, they can do 5192 this through this parameter. Its format is a gnutls priority 5193 string as described at 5194 https://gnutls.org/manual/html_node/Priority-Strings.html. 5195 5196 ``-object tls-cipher-suites,id=id,priority=priority`` 5197 Creates a TLS cipher suites object, which can be used to control 5198 the TLS cipher/protocol algorithms that applications are permitted 5199 to use. 5200 5201 The ``id`` parameter is a unique ID which frontends will use to 5202 access the ordered list of permitted TLS cipher suites from the 5203 host. 5204 5205 The ``priority`` parameter allows to override the global default 5206 priority used by gnutls. This can be useful if the system 5207 administrator needs to use a weaker set of crypto priorities for 5208 QEMU without potentially forcing the weakness onto all 5209 applications. Or conversely if one wants wants a stronger 5210 default for QEMU than for all other applications, they can do 5211 this through this parameter. Its format is a gnutls priority 5212 string as described at 5213 https://gnutls.org/manual/html_node/Priority-Strings.html. 5214 5215 An example of use of this object is to control UEFI HTTPS Boot. 5216 The tls-cipher-suites object exposes the ordered list of permitted 5217 TLS cipher suites from the host side to the guest firmware, via 5218 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5219 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5220 guest-side TLS. 5221 5222 In the following example, the priority at which the host-side policy 5223 is retrieved is given by the ``priority`` property. 5224 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5225 refer to /etc/crypto-policies/back-ends/gnutls.config. 5226 5227 .. parsed-literal:: 5228 5229 # |qemu_system| \\ 5230 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5231 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5232 5233 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5234 Interval t can't be 0, this filter batches the packet delivery: 5235 all packets arriving in a given interval on netdev netdevid are 5236 delayed until the end of the interval. Interval is in 5237 microseconds. ``status`` is optional that indicate whether the 5238 netfilter is on (enabled) or off (disabled), the default status 5239 for netfilter will be 'on'. 5240 5241 queue all\|rx\|tx is an option that can be applied to any 5242 netfilter. 5243 5244 ``all``: the filter is attached both to the receive and the 5245 transmit queue of the netdev (default). 5246 5247 ``rx``: the filter is attached to the receive queue of the 5248 netdev, where it will receive packets sent to the netdev. 5249 5250 ``tx``: the filter is attached to the transmit queue of the 5251 netdev, where it will receive packets sent by the netdev. 5252 5253 position head\|tail\|id=<id> is an option to specify where the 5254 filter should be inserted in the filter list. It can be applied 5255 to any netfilter. 5256 5257 ``head``: the filter is inserted at the head of the filter list, 5258 before any existing filters. 5259 5260 ``tail``: the filter is inserted at the tail of the filter list, 5261 behind any existing filters (default). 5262 5263 ``id=<id>``: the filter is inserted before or behind the filter 5264 specified by <id>, see the insert option below. 5265 5266 insert behind\|before is an option to specify where to insert 5267 the new filter relative to the one specified with 5268 position=id=<id>. It can be applied to any netfilter. 5269 5270 ``before``: insert before the specified filter. 5271 5272 ``behind``: insert behind the specified filter (default). 5273 5274 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5275 filter-mirror on netdev netdevid,mirror net packet to 5276 chardevchardevid, if it has the vnet\_hdr\_support flag, 5277 filter-mirror will mirror packet with vnet\_hdr\_len. 5278 5279 ``-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]`` 5280 filter-redirector on netdev netdevid,redirect filter's net 5281 packet to chardev chardevid,and redirect indev's packet to 5282 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5283 will redirect packet with vnet\_hdr\_len. Create a 5284 filter-redirector we need to differ outdev id from indev id, id 5285 can not be the same. we can just use indev or outdev, but at 5286 least one of indev or outdev need to be specified. 5287 5288 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5289 Filter-rewriter is a part of COLO project.It will rewrite tcp 5290 packet to secondary from primary to keep secondary tcp 5291 connection,and rewrite tcp packet to primary from secondary make 5292 tcp packet can be handled by client.if it has the 5293 vnet\_hdr\_support flag, we can parse packet with vnet header. 5294 5295 usage: colo secondary: -object 5296 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5297 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5298 filter-rewriter,id=rew0,netdev=hn0,queue=all 5299 5300 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5301 Dump the network traffic on netdev dev to the file specified by 5302 filename. At most len bytes (64k by default) per packet are 5303 stored. The file format is libpcap, so it can be analyzed with 5304 tools such as tcpdump or Wireshark. 5305 5306 ``-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}]`` 5307 Colo-compare gets packet from primary\_in chardevid and 5308 secondary\_in, then compare whether the payload of primary packet 5309 and secondary packet are the same. If same, it will output 5310 primary packet to out\_dev, else it will notify COLO-framework to do 5311 checkpoint and send primary packet to out\_dev. In order to 5312 improve efficiency, we need to put the task of comparison in 5313 another iothread. If it has the vnet\_hdr\_support flag, 5314 colo compare will send/recv packet with vnet\_hdr\_len. 5315 The compare\_timeout=@var{ms} determines the maximum time of the 5316 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5317 is to set the period of scanning expired primary node network packets. 5318 The max\_queue\_size=@var{size} is to set the max compare queue 5319 size depend on user environment. 5320 If user want to use Xen COLO, need to add the notify\_dev to 5321 notify Xen colo-frame to do checkpoint. 5322 5323 COLO-compare must be used with the help of filter-mirror, 5324 filter-redirector and filter-rewriter. 5325 5326 :: 5327 5328 KVM COLO 5329 5330 primary: 5331 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5332 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5333 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5334 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5335 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5336 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5337 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5338 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5339 -object iothread,id=iothread1 5340 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5341 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5342 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5343 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5344 5345 secondary: 5346 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5347 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5348 -chardev socket,id=red0,host=3.3.3.3,port=9003 5349 -chardev socket,id=red1,host=3.3.3.3,port=9004 5350 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5351 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5352 5353 5354 Xen COLO 5355 5356 primary: 5357 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5358 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5359 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5360 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5361 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5362 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5363 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5364 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5365 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5366 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5367 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5368 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5369 -object iothread,id=iothread1 5370 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5371 5372 secondary: 5373 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5374 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5375 -chardev socket,id=red0,host=3.3.3.3,port=9003 5376 -chardev socket,id=red1,host=3.3.3.3,port=9004 5377 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5378 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5379 5380 If you want to know the detail of above command line, you can 5381 read the colo-compare git log. 5382 5383 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5384 Creates a cryptodev backend which executes crypto operations from 5385 the QEMU cipher APIs. The id parameter is a unique ID that will 5386 be used to reference this cryptodev backend from the 5387 ``virtio-crypto`` device. The queues parameter is optional, 5388 which specify the queue number of cryptodev backend, the default 5389 of queues is 1. 5390 5391 .. parsed-literal:: 5392 5393 # |qemu_system| \\ 5394 [...] \\ 5395 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5396 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5397 [...] 5398 5399 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5400 Creates a vhost-user cryptodev backend, backed by a chardev 5401 chardevid. The id parameter is a unique ID that will be used to 5402 reference this cryptodev backend from the ``virtio-crypto`` 5403 device. The chardev should be a unix domain socket backed one. 5404 The vhost-user uses a specifically defined protocol to pass 5405 vhost ioctl replacement messages to an application on the other 5406 end of the socket. The queues parameter is optional, which 5407 specify the queue number of cryptodev backend for multiqueue 5408 vhost-user, the default of queues is 1. 5409 5410 .. parsed-literal:: 5411 5412 # |qemu_system| \\ 5413 [...] \\ 5414 -chardev socket,id=chardev0,path=/path/to/socket \\ 5415 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5416 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5417 [...] 5418 5419 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5420 \ 5421 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5422 Defines a secret to store a password, encryption key, or some 5423 other sensitive data. The sensitive data can either be passed 5424 directly via the data parameter, or indirectly via the file 5425 parameter. Using the data parameter is insecure unless the 5426 sensitive data is encrypted. 5427 5428 The sensitive data can be provided in raw format (the default), 5429 or base64. When encoded as JSON, the raw format only supports 5430 valid UTF-8 characters, so base64 is recommended for sending 5431 binary data. QEMU will convert from which ever format is 5432 provided to the format it needs internally. eg, an RBD password 5433 can be provided in raw format, even though it will be base64 5434 encoded when passed onto the RBD sever. 5435 5436 For added protection, it is possible to encrypt the data 5437 associated with a secret using the AES-256-CBC cipher. Use of 5438 encryption is indicated by providing the keyid and iv 5439 parameters. The keyid parameter provides the ID of a previously 5440 defined secret that contains the AES-256 decryption key. This 5441 key should be 32-bytes long and be base64 encoded. The iv 5442 parameter provides the random initialization vector used for 5443 encryption of this particular secret and should be a base64 5444 encrypted string of the 16-byte IV. 5445 5446 The simplest (insecure) usage is to provide the secret inline 5447 5448 .. parsed-literal:: 5449 5450 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5451 5452 The simplest secure usage is to provide the secret via a file 5453 5454 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5455 secret,id=sec0,file=mypasswd.txt,format=raw 5456 5457 For greater security, AES-256-CBC should be used. To illustrate 5458 usage, consider the openssl command line tool which can encrypt 5459 the data. Note that when encrypting, the plaintext must be 5460 padded to the cipher block size (32 bytes) using the standard 5461 PKCS#5/6 compatible padding algorithm. 5462 5463 First a master key needs to be created in base64 encoding: 5464 5465 :: 5466 5467 # openssl rand -base64 32 > key.b64 5468 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5469 5470 Each secret to be encrypted needs to have a random 5471 initialization vector generated. These do not need to be kept 5472 secret 5473 5474 :: 5475 5476 # openssl rand -base64 16 > iv.b64 5477 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5478 5479 The secret to be defined can now be encrypted, in this case 5480 we're telling openssl to base64 encode the result, but it could 5481 be left as raw bytes if desired. 5482 5483 :: 5484 5485 # SECRET=$(printf "letmein" | 5486 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5487 5488 When launching QEMU, create a master secret pointing to 5489 ``key.b64`` and specify that to be used to decrypt the user 5490 password. Pass the contents of ``iv.b64`` to the second secret 5491 5492 .. parsed-literal:: 5493 5494 # |qemu_system| \\ 5495 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5496 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5497 data=$SECRET,iv=$(<iv.b64) 5498 5499 ``-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]`` 5500 Create a Secure Encrypted Virtualization (SEV) guest object, 5501 which can be used to provide the guest memory encryption support 5502 on AMD processors. 5503 5504 When memory encryption is enabled, one of the physical address 5505 bit (aka the C-bit) is utilized to mark if a memory page is 5506 protected. The ``cbitpos`` is used to provide the C-bit 5507 position. The C-bit position is Host family dependent hence user 5508 must provide this value. On EPYC, the value should be 47. 5509 5510 When memory encryption is enabled, we loose certain bits in 5511 physical address space. The ``reduced-phys-bits`` is used to 5512 provide the number of bits we loose in physical address space. 5513 Similar to C-bit, the value is Host family dependent. On EPYC, 5514 a guest will lose a maximum of 1 bit, so the value should be 1. 5515 5516 The ``sev-device`` provides the device file to use for 5517 communicating with the SEV firmware running inside AMD Secure 5518 Processor. The default device is '/dev/sev'. If hardware 5519 supports memory encryption then /dev/sev devices are created by 5520 CCP driver. 5521 5522 The ``policy`` provides the guest policy to be enforced by the 5523 SEV firmware and restrict what configuration and operational 5524 commands can be performed on this guest by the hypervisor. The 5525 policy should be provided by the guest owner and is bound to the 5526 guest and cannot be changed throughout the lifetime of the 5527 guest. The default is 0. 5528 5529 If guest ``policy`` allows sharing the key with another SEV 5530 guest then ``handle`` can be use to provide handle of the guest 5531 from which to share the key. 5532 5533 The ``dh-cert-file`` and ``session-file`` provides the guest 5534 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5535 and session parameters are used for establishing a cryptographic 5536 session with the guest owner to negotiate keys used for 5537 attestation. The file must be encoded in base64. 5538 5539 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5540 cmdline to a designated guest firmware page for measured Linux 5541 boot with -kernel. The default is off. (Since 6.2) 5542 5543 e.g to launch a SEV guest 5544 5545 .. parsed-literal:: 5546 5547 # |qemu_system_x86| \\ 5548 ...... \\ 5549 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5550 -machine ...,memory-encryption=sev0 \\ 5551 ..... 5552 5553 ``-object authz-simple,id=id,identity=string`` 5554 Create an authorization object that will control access to 5555 network services. 5556 5557 The ``identity`` parameter is identifies the user and its format 5558 depends on the network service that authorization object is 5559 associated with. For authorizing based on TLS x509 certificates, 5560 the identity must be the x509 distinguished name. Note that care 5561 must be taken to escape any commas in the distinguished name. 5562 5563 An example authorization object to validate a x509 distinguished 5564 name would look like: 5565 5566 .. parsed-literal:: 5567 5568 # |qemu_system| \\ 5569 ... \\ 5570 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5571 ... 5572 5573 Note the use of quotes due to the x509 distinguished name 5574 containing whitespace, and escaping of ','. 5575 5576 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5577 Create an authorization object that will control access to 5578 network services. 5579 5580 The ``filename`` parameter is the fully qualified path to a file 5581 containing the access control list rules in JSON format. 5582 5583 An example set of rules that match against SASL usernames might 5584 look like: 5585 5586 :: 5587 5588 { 5589 "rules": [ 5590 { "match": "fred", "policy": "allow", "format": "exact" }, 5591 { "match": "bob", "policy": "allow", "format": "exact" }, 5592 { "match": "danb", "policy": "deny", "format": "glob" }, 5593 { "match": "dan*", "policy": "allow", "format": "exact" }, 5594 ], 5595 "policy": "deny" 5596 } 5597 5598 When checking access the object will iterate over all the rules 5599 and the first rule to match will have its ``policy`` value 5600 returned as the result. If no rules match, then the default 5601 ``policy`` value is returned. 5602 5603 The rules can either be an exact string match, or they can use 5604 the simple UNIX glob pattern matching to allow wildcards to be 5605 used. 5606 5607 If ``refresh`` is set to true the file will be monitored and 5608 automatically reloaded whenever its content changes. 5609 5610 As with the ``authz-simple`` object, the format of the identity 5611 strings being matched depends on the network service, but is 5612 usually a TLS x509 distinguished name, or a SASL username. 5613 5614 An example authorization object to validate a SASL username 5615 would look like: 5616 5617 .. parsed-literal:: 5618 5619 # |qemu_system| \\ 5620 ... \\ 5621 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5622 ... 5623 5624 ``-object authz-pam,id=id,service=string`` 5625 Create an authorization object that will control access to 5626 network services. 5627 5628 The ``service`` parameter provides the name of a PAM service to 5629 use for authorization. It requires that a file 5630 ``/etc/pam.d/service`` exist to provide the configuration for 5631 the ``account`` subsystem. 5632 5633 An example authorization object to validate a TLS x509 5634 distinguished name would look like: 5635 5636 .. parsed-literal:: 5637 5638 # |qemu_system| \\ 5639 ... \\ 5640 -object authz-pam,id=auth0,service=qemu-vnc \\ 5641 ... 5642 5643 There would then be a corresponding config file for PAM at 5644 ``/etc/pam.d/qemu-vnc`` that contains: 5645 5646 :: 5647 5648 account requisite pam_listfile.so item=user sense=allow \ 5649 file=/etc/qemu/vnc.allow 5650 5651 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5652 of x509 distinguished names that are permitted access 5653 5654 :: 5655 5656 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5657 5658 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5659 Creates a dedicated event loop thread that devices can be 5660 assigned to. This is known as an IOThread. By default device 5661 emulation happens in vCPU threads or the main event loop thread. 5662 This can become a scalability bottleneck. IOThreads allow device 5663 emulation and I/O to run on other host CPUs. 5664 5665 The ``id`` parameter is a unique ID that will be used to 5666 reference this IOThread from ``-device ...,iothread=id``. 5667 Multiple devices can be assigned to an IOThread. Note that not 5668 all devices support an ``iothread`` parameter. 5669 5670 The ``query-iothreads`` QMP command lists IOThreads and reports 5671 their thread IDs so that the user can configure host CPU 5672 pinning/affinity. 5673 5674 IOThreads use an adaptive polling algorithm to reduce event loop 5675 latency. Instead of entering a blocking system call to monitor 5676 file descriptors and then pay the cost of being woken up when an 5677 event occurs, the polling algorithm spins waiting for events for 5678 a short time. The algorithm's default parameters are suitable 5679 for many cases but can be adjusted based on knowledge of the 5680 workload and/or host device latency. 5681 5682 The ``poll-max-ns`` parameter is the maximum number of 5683 nanoseconds to busy wait for events. Polling can be disabled by 5684 setting this value to 0. 5685 5686 The ``poll-grow`` parameter is the multiplier used to increase 5687 the polling time when the algorithm detects it is missing events 5688 due to not polling long enough. 5689 5690 The ``poll-shrink`` parameter is the divisor used to decrease 5691 the polling time when the algorithm detects it is spending too 5692 long polling without encountering events. 5693 5694 The ``aio-max-batch`` parameter is the maximum number of requests 5695 in a batch for the AIO engine, 0 means that the engine will use 5696 its default. 5697 5698 The IOThread parameters can be modified at run-time using the 5699 ``qom-set`` command (where ``iothread1`` is the IOThread's 5700 ``id``): 5701 5702 :: 5703 5704 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5705ERST 5706 5707 5708HXCOMM This is the last statement. Insert new options before this line! 5709 5710#undef DEF 5711#undef DEFHEADING 5712#undef ARCHHEADING 5713
