1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST version and 3HXCOMM discarded from C version. 4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 5HXCOMM construct option structures, enums and help message for specified 6HXCOMM architectures. 7HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 40 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 41 QEMU_ARCH_ALL) 42SRST 43``-machine [type=]name[,prop=value[,...]]`` 44 Select the emulated machine by name. Use ``-machine help`` to list 45 available machines. 46 47 For architectures which aim to support live migration compatibility 48 across releases, each release will introduce a new versioned machine 49 type. For example, the 2.8.0 release introduced machine types 50 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 51 52 To allow live migration of guests from QEMU version 2.8.0, to QEMU 53 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 54 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 55 skip multiple intermediate releases when upgrading, new releases of 56 QEMU will support machine types from many previous versions. 57 58 Supported machine properties are: 59 60 ``accel=accels1[:accels2[:...]]`` 61 This is used to enable an accelerator. Depending on the target 62 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 63 By default, tcg is used. If there is more than one accelerator 64 specified, the next one is used if the previous one fails to 65 initialize. 66 67 ``vmport=on|off|auto`` 68 Enables emulation of VMWare IO port, for vmmouse etc. auto says 69 to select the value based on accel. For accel=xen the default is 70 off otherwise the default is on. 71 72 ``dump-guest-core=on|off`` 73 Include guest memory in a core dump. The default is on. 74 75 ``mem-merge=on|off`` 76 Enables or disables memory merge support. This feature, when 77 supported by the host, de-duplicates identical memory pages 78 among VMs instances (enabled by default). 79 80 ``aes-key-wrap=on|off`` 81 Enables or disables AES key wrapping support on s390-ccw hosts. 82 This feature controls whether AES wrapping keys will be created 83 to allow execution of AES cryptographic functions. The default 84 is on. 85 86 ``dea-key-wrap=on|off`` 87 Enables or disables DEA key wrapping support on s390-ccw hosts. 88 This feature controls whether DEA wrapping keys will be created 89 to allow execution of DEA cryptographic functions. The default 90 is on. 91 92 ``nvdimm=on|off`` 93 Enables or disables NVDIMM support. The default is off. 94 95 ``memory-encryption=`` 96 Memory encryption object to use. The default is none. 97 98 ``hmat=on|off`` 99 Enables or disables ACPI Heterogeneous Memory Attribute Table 100 (HMAT) support. The default is off. 101 102 ``memory-backend='id'`` 103 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 104 Allows to use a memory backend as main RAM. 105 106 For example: 107 :: 108 109 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 110 -machine memory-backend=pc.ram 111 -m 512M 112 113 Migration compatibility note: 114 115 * as backend id one shall use value of 'default-ram-id', advertised by 116 machine type (available via ``query-machines`` QMP command), if migration 117 to/from old QEMU (<5.0) is expected. 118 * for machine types 4.0 and older, user shall 119 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 120 if migration to/from old QEMU (<5.0) is expected. 121 122 For example: 123 :: 124 125 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 126 -machine memory-backend=pc.ram 127 -m 512M 128 129 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 130 Define a CXL Fixed Memory Window (CFMW). 131 132 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 133 134 They are regions of Host Physical Addresses (HPA) on a system which 135 may be interleaved across one or more CXL host bridges. The system 136 software will assign particular devices into these windows and 137 configure the downstream Host-managed Device Memory (HDM) decoders 138 in root ports, switch ports and devices appropriately to meet the 139 interleave requirements before enabling the memory devices. 140 141 ``targets.X=target`` provides the mapping to CXL host bridges 142 which may be identified by the id provided in the -device entry. 143 Multiple entries are needed to specify all the targets when 144 the fixed memory window represents interleaved memory. X is the 145 target index from 0. 146 147 ``size=size`` sets the size of the CFMW. This must be a multiple of 148 256MiB. The region will be aligned to 256MiB but the location is 149 platform and configuration dependent. 150 151 ``interleave-granularity=granularity`` sets the granularity of 152 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 153 4096KiB, 8192KiB and 16384KiB granularities supported. 154 155 Example: 156 157 :: 158 159 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k 160ERST 161 162DEF("M", HAS_ARG, QEMU_OPTION_M, 163 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 164 QEMU_ARCH_ALL) 165 166SRST 167``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 168 Define an SGX EPC section. 169ERST 170 171DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 172 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 173SRST 174``-cpu model`` 175 Select CPU model (``-cpu help`` for list and additional feature 176 selection) 177ERST 178 179DEF("accel", HAS_ARG, QEMU_OPTION_accel, 180 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 181 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 182 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 183 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 184 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 185 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 186 " split-wx=on|off (enable TCG split w^x mapping)\n" 187 " tb-size=n (TCG translation block cache size)\n" 188 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 189 " 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, 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). This 1739 option is deprecated (since QEMU 8.1) and will be removed in a future 1740 version of QEMU. Use ``local`` instead. 1741 1742 ``synth`` 1743 Synthetic filesystem, only used by QTests. 1744 1745 ``id=id`` 1746 Specifies identifier for this device. 1747 1748 ``path=path`` 1749 Specifies the export path for the file system device. Files 1750 under this path will be available to the 9p client on the guest. 1751 1752 ``security_model=security_model`` 1753 Specifies the security model to be used for this export path. 1754 Supported security models are "passthrough", "mapped-xattr", 1755 "mapped-file" and "none". In "passthrough" security model, files 1756 are stored using the same credentials as they are created on the 1757 guest. This requires QEMU to run as root. In "mapped-xattr" 1758 security model, some of the file attributes like uid, gid, mode 1759 bits and link target are stored as file attributes. For 1760 "mapped-file" these attributes are stored in the hidden 1761 .virtfs\_metadata directory. Directories exported by this 1762 security model cannot interact with other unix tools. "none" 1763 security model is same as passthrough except the sever won't 1764 report failures if it fails to set file attributes like 1765 ownership. Security model is mandatory only for local fsdriver. 1766 Other fsdrivers (like proxy) don't take security model as a 1767 parameter. 1768 1769 ``writeout=writeout`` 1770 This is an optional argument. The only supported value is 1771 "immediate". This means that host page cache will be used to 1772 read and write data but write notification will be sent to the 1773 guest only when the data has been reported as written by the 1774 storage subsystem. 1775 1776 ``readonly=on`` 1777 Enables exporting 9p share as a readonly mount for guests. By 1778 default read-write access is given. 1779 1780 ``socket=socket`` 1781 Enables proxy filesystem driver to use passed socket file for 1782 communicating with virtfs-proxy-helper(1). 1783 1784 ``sock_fd=sock_fd`` 1785 Enables proxy filesystem driver to use passed socket descriptor 1786 for communicating with virtfs-proxy-helper(1). Usually a helper 1787 like libvirt will create socketpair and pass one of the fds as 1788 sock\_fd. 1789 1790 ``fmode=fmode`` 1791 Specifies the default mode for newly created files on the host. 1792 Works only with security models "mapped-xattr" and 1793 "mapped-file". 1794 1795 ``dmode=dmode`` 1796 Specifies the default mode for newly created directories on the 1797 host. Works only with security models "mapped-xattr" and 1798 "mapped-file". 1799 1800 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1801 Specify bandwidth throttling limits in bytes per second, either 1802 for all request types or for reads or writes only. 1803 1804 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1805 Specify bursts in bytes per second, either for all request types 1806 or for reads or writes only. Bursts allow the guest I/O to spike 1807 above the limit temporarily. 1808 1809 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1810 Specify request rate limits in requests per second, either for 1811 all request types or for reads or writes only. 1812 1813 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1814 Specify bursts in requests per second, either for all request 1815 types or for reads or writes only. Bursts allow the guest I/O to 1816 spike above the limit temporarily. 1817 1818 ``throttling.iops-size=is`` 1819 Let every is bytes of a request count as a new request for iops 1820 throttling purposes. 1821 1822 -fsdev option is used along with -device driver "virtio-9p-...". 1823 1824``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1825 Options for virtio-9p-... driver are: 1826 1827 ``type`` 1828 Specifies the variant to be used. Supported values are "pci", 1829 "ccw" or "device", depending on the machine type. 1830 1831 ``fsdev=id`` 1832 Specifies the id value specified along with -fsdev option. 1833 1834 ``mount_tag=mount_tag`` 1835 Specifies the tag name to be used by the guest to mount this 1836 export point. 1837ERST 1838 1839DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1840 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1841 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1842 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1843 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1844 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1845 QEMU_ARCH_ALL) 1846 1847SRST 1848``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1849 \ 1850``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1851 \ 1852``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1853 \ 1854``-virtfs synth,mount_tag=mount_tag`` 1855 Define a new virtual filesystem device and expose it to the guest using 1856 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1857 directory on host is made directly accessible by guest as a pass-through 1858 file system by using the 9P network protocol for communication between 1859 host and guests, if desired even accessible, shared by several guests 1860 simultaneously. 1861 1862 Note that ``-virtfs`` is actually just a convenience shortcut for its 1863 generalized form ``-fsdev -device virtio-9p-pci``. 1864 1865 The general form of pass-through file system options are: 1866 1867 ``local`` 1868 Accesses to the filesystem are done by QEMU. 1869 1870 ``proxy`` 1871 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1872 This option is deprecated (since QEMU 8.1) and will be removed in a 1873 future version of QEMU. Use ``local`` instead. 1874 1875 ``synth`` 1876 Synthetic filesystem, only used by QTests. 1877 1878 ``id=id`` 1879 Specifies identifier for the filesystem device 1880 1881 ``path=path`` 1882 Specifies the export path for the file system device. Files 1883 under this path will be available to the 9p client on the guest. 1884 1885 ``security_model=security_model`` 1886 Specifies the security model to be used for this export path. 1887 Supported security models are "passthrough", "mapped-xattr", 1888 "mapped-file" and "none". In "passthrough" security model, files 1889 are stored using the same credentials as they are created on the 1890 guest. This requires QEMU to run as root. In "mapped-xattr" 1891 security model, some of the file attributes like uid, gid, mode 1892 bits and link target are stored as file attributes. For 1893 "mapped-file" these attributes are stored in the hidden 1894 .virtfs\_metadata directory. Directories exported by this 1895 security model cannot interact with other unix tools. "none" 1896 security model is same as passthrough except the sever won't 1897 report failures if it fails to set file attributes like 1898 ownership. Security model is mandatory only for local fsdriver. 1899 Other fsdrivers (like proxy) don't take security model as a 1900 parameter. 1901 1902 ``writeout=writeout`` 1903 This is an optional argument. The only supported value is 1904 "immediate". This means that host page cache will be used to 1905 read and write data but write notification will be sent to the 1906 guest only when the data has been reported as written by the 1907 storage subsystem. 1908 1909 ``readonly=on`` 1910 Enables exporting 9p share as a readonly mount for guests. By 1911 default read-write access is given. 1912 1913 ``socket=socket`` 1914 Enables proxy filesystem driver to use passed socket file for 1915 communicating with virtfs-proxy-helper(1). Usually a helper like 1916 libvirt will create socketpair and pass one of the fds as 1917 sock\_fd. 1918 1919 ``sock_fd`` 1920 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1921 socket descriptor for interfacing with virtfs-proxy-helper(1). 1922 1923 ``fmode=fmode`` 1924 Specifies the default mode for newly created files on the host. 1925 Works only with security models "mapped-xattr" and 1926 "mapped-file". 1927 1928 ``dmode=dmode`` 1929 Specifies the default mode for newly created directories on the 1930 host. Works only with security models "mapped-xattr" and 1931 "mapped-file". 1932 1933 ``mount_tag=mount_tag`` 1934 Specifies the tag name to be used by the guest to mount this 1935 export point. 1936 1937 ``multidevs=multidevs`` 1938 Specifies how to deal with multiple devices being shared with a 1939 9p export. Supported behaviours are either "remap", "forbid" or 1940 "warn". The latter is the default behaviour on which virtfs 9p 1941 expects only one device to be shared with the same export, and 1942 if more than one device is shared and accessed via the same 9p 1943 export then only a warning message is logged (once) by qemu on 1944 host side. In order to avoid file ID collisions on guest you 1945 should either create a separate virtfs export for each device to 1946 be shared with guests (recommended way) or you might use "remap" 1947 instead which allows you to share multiple devices with only one 1948 export instead, which is achieved by remapping the original 1949 inode numbers from host to guest in a way that would prevent 1950 such collisions. Remapping inodes in such use cases is required 1951 because the original device IDs from host are never passed and 1952 exposed on guest. Instead all files of an export shared with 1953 virtfs always share the same device id on guest. So two files 1954 with identical inode numbers but from actually different devices 1955 on host would otherwise cause a file ID collision and hence 1956 potential misbehaviours on guest. "forbid" on the other hand 1957 assumes like "warn" that only one device is shared by the same 1958 export, however it will not only log a warning message but also 1959 deny access to additional devices on guest. Note though that 1960 "forbid" does currently not block all possible file access 1961 operations (e.g. readdir() would still return entries from other 1962 devices). 1963ERST 1964 1965DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1966 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1967 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1968 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1969 " [,timeout=timeout]\n" 1970 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1971 1972SRST 1973``-iscsi`` 1974 Configure iSCSI session parameters. 1975ERST 1976 1977DEFHEADING() 1978 1979DEFHEADING(USB convenience options:) 1980 1981DEF("usb", 0, QEMU_OPTION_usb, 1982 "-usb enable on-board USB host controller (if not enabled by default)\n", 1983 QEMU_ARCH_ALL) 1984SRST 1985``-usb`` 1986 Enable USB emulation on machine types with an on-board USB host 1987 controller (if not enabled by default). Note that on-board USB host 1988 controllers may not support USB 3.0. In this case 1989 ``-device qemu-xhci`` can be used instead on machines with PCI. 1990ERST 1991 1992DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1993 "-usbdevice name add the host or guest USB device 'name'\n", 1994 QEMU_ARCH_ALL) 1995SRST 1996``-usbdevice devname`` 1997 Add the USB device devname, and enable an on-board USB controller 1998 if possible and necessary (just like it can be done via 1999 ``-machine usb=on``). Note that this option is mainly intended for 2000 the user's convenience only. More fine-grained control can be 2001 achieved by selecting a USB host controller (if necessary) and the 2002 desired USB device via the ``-device`` option instead. For example, 2003 instead of using ``-usbdevice mouse`` it is possible to use 2004 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2005 to a USB 3.0 controller instead (at least on machines that support 2006 PCI and do not have an USB controller enabled by default yet). 2007 For more details, see the chapter about 2008 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2009 Possible devices for devname are: 2010 2011 ``braille`` 2012 Braille device. This will use BrlAPI to display the braille 2013 output on a real or fake device (i.e. it also creates a 2014 corresponding ``braille`` chardev automatically beside the 2015 ``usb-braille`` USB device). 2016 2017 ``keyboard`` 2018 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2019 2020 ``mouse`` 2021 Virtual Mouse. This will override the PS/2 mouse emulation when 2022 activated. 2023 2024 ``tablet`` 2025 Pointer device that uses absolute coordinates (like a 2026 touchscreen). This means QEMU is able to report the mouse 2027 position without having to grab the mouse. Also overrides the 2028 PS/2 mouse emulation when activated. 2029 2030 ``wacom-tablet`` 2031 Wacom PenPartner USB tablet. 2032 2033 2034ERST 2035 2036DEFHEADING() 2037 2038DEFHEADING(Display options:) 2039 2040DEF("display", HAS_ARG, QEMU_OPTION_display, 2041#if defined(CONFIG_SPICE) 2042 "-display spice-app[,gl=on|off]\n" 2043#endif 2044#if defined(CONFIG_SDL) 2045 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2046 " [,window-close=on|off]\n" 2047#endif 2048#if defined(CONFIG_GTK) 2049 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2050 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2051 " [,show-menubar=on|off]\n" 2052#endif 2053#if defined(CONFIG_VNC) 2054 "-display vnc=<display>[,<optargs>]\n" 2055#endif 2056#if defined(CONFIG_CURSES) 2057 "-display curses[,charset=<encoding>]\n" 2058#endif 2059#if defined(CONFIG_COCOA) 2060 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2061#endif 2062#if defined(CONFIG_OPENGL) 2063 "-display egl-headless[,rendernode=<file>]\n" 2064#endif 2065#if defined(CONFIG_DBUS_DISPLAY) 2066 "-display dbus[,addr=<dbusaddr>]\n" 2067 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2068#endif 2069#if defined(CONFIG_COCOA) 2070 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 2071#endif 2072 "-display none\n" 2073 " select display backend type\n" 2074 " The default display is equivalent to\n " 2075#if defined(CONFIG_GTK) 2076 "\"-display gtk\"\n" 2077#elif defined(CONFIG_SDL) 2078 "\"-display sdl\"\n" 2079#elif defined(CONFIG_COCOA) 2080 "\"-display cocoa\"\n" 2081#elif defined(CONFIG_VNC) 2082 "\"-vnc localhost:0,to=99,id=default\"\n" 2083#else 2084 "\"-display none\"\n" 2085#endif 2086 , QEMU_ARCH_ALL) 2087SRST 2088``-display type`` 2089 Select type of display to use. Use ``-display help`` to list the available 2090 display types. Valid values for type are 2091 2092 ``spice-app[,gl=on|off]`` 2093 Start QEMU as a Spice server and launch the default Spice client 2094 application. The Spice server will redirect the serial consoles 2095 and QEMU monitors. (Since 4.0) 2096 2097 ``dbus`` 2098 Export the display over D-Bus interfaces. (Since 7.0) 2099 2100 The connection is registered with the "org.qemu" name (and queued when 2101 already owned). 2102 2103 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2104 2105 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2106 2107 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2108 will share framebuffers with DMABUF file descriptors). 2109 2110 ``sdl`` 2111 Display video output via SDL (usually in a separate graphics 2112 window; see the SDL documentation for other possibilities). 2113 Valid parameters are: 2114 2115 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2116 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2117 either ``lshift-lctrl-lalt`` or ``rctrl``. 2118 2119 ``gl=on|off|core|es`` : Use OpenGL for displaying 2120 2121 ``show-cursor=on|off`` : Force showing the mouse cursor 2122 2123 ``window-close=on|off`` : Allow to quit qemu with window close button 2124 2125 ``gtk`` 2126 Display video output in a GTK window. This interface provides 2127 drop-down menus and other UI elements to configure and control 2128 the VM during runtime. Valid parameters are: 2129 2130 ``full-screen=on|off`` : Start in fullscreen mode 2131 2132 ``gl=on|off`` : Use OpenGL for displaying 2133 2134 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2135 2136 ``show-tabs=on|off`` : Display the tab bar for switching between the 2137 various graphical interfaces (e.g. VGA and 2138 virtual console character devices) by default. 2139 2140 ``show-cursor=on|off`` : Force showing the mouse cursor 2141 2142 ``window-close=on|off`` : Allow to quit qemu with window close button 2143 2144 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2145 2146 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2147 defaults to "off" 2148 2149 ``curses[,charset=<encoding>]`` 2150 Display video output via curses. For graphics device models 2151 which support a text mode, QEMU can display this output using a 2152 curses/ncurses interface. Nothing is displayed when the graphics 2153 device is in graphical mode or if the graphics device does not 2154 support a text mode. Generally only the VGA device models 2155 support text mode. The font charset used by the guest can be 2156 specified with the ``charset`` option, for example 2157 ``charset=CP850`` for IBM CP850 encoding. The default is 2158 ``CP437``. 2159 2160 ``cocoa`` 2161 Display video output in a Cocoa window. Mac only. This interface 2162 provides drop-down menus and other UI elements to configure and 2163 control the VM during runtime. Valid parameters are: 2164 2165 ``show-cursor=on|off`` : Force showing the mouse cursor 2166 2167 ``left-command-key=on|off`` : Disable forwarding left command key to host 2168 2169 ``egl-headless[,rendernode=<file>]`` 2170 Offload all OpenGL operations to a local DRI device. For any 2171 graphical display, this display needs to be paired with either 2172 VNC or SPICE displays. 2173 2174 ``vnc=<display>`` 2175 Start a VNC server on display <display> 2176 2177 ``none`` 2178 Do not display video output. The guest will still see an 2179 emulated graphics card, but its output will not be displayed to 2180 the QEMU user. This option differs from the -nographic option in 2181 that it only affects what is done with video output; -nographic 2182 also changes the destination of the serial and parallel port 2183 data. 2184ERST 2185 2186DEF("nographic", 0, QEMU_OPTION_nographic, 2187 "-nographic disable graphical output and redirect serial I/Os to console\n", 2188 QEMU_ARCH_ALL) 2189SRST 2190``-nographic`` 2191 Normally, if QEMU is compiled with graphical window support, it 2192 displays output such as guest graphics, guest console, and the QEMU 2193 monitor in a window. With this option, you can totally disable 2194 graphical output so that QEMU is a simple command line application. 2195 The emulated serial port is redirected on the console and muxed with 2196 the monitor (unless redirected elsewhere explicitly). Therefore, you 2197 can still use QEMU to debug a Linux kernel with a serial console. 2198 Use C-a h for help on switching between the console and monitor. 2199ERST 2200 2201#ifdef CONFIG_SPICE 2202DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2203 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2204 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2205 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2206 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2207 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2208 " [,tls-ciphers=<list>]\n" 2209 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2210 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2211 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2212 " [,password-secret=<secret-id>]\n" 2213 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2214 " [,jpeg-wan-compression=[auto|never|always]]\n" 2215 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2216 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2217 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2218 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2219 " [,gl=[on|off]][,rendernode=<file>]\n" 2220 " enable spice\n" 2221 " at least one of {port, tls-port} is mandatory\n", 2222 QEMU_ARCH_ALL) 2223#endif 2224SRST 2225``-spice option[,option[,...]]`` 2226 Enable the spice remote desktop protocol. Valid options are 2227 2228 ``port=<nr>`` 2229 Set the TCP port spice is listening on for plaintext channels. 2230 2231 ``addr=<addr>`` 2232 Set the IP address spice is listening on. Default is any 2233 address. 2234 2235 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2236 Force using the specified IP version. 2237 2238 ``password-secret=<secret-id>`` 2239 Set the ID of the ``secret`` object containing the password 2240 you need to authenticate. 2241 2242 ``sasl=on|off`` 2243 Require that the client use SASL to authenticate with the spice. 2244 The exact choice of authentication method used is controlled 2245 from the system / user's SASL configuration file for the 'qemu' 2246 service. This is typically found in /etc/sasl2/qemu.conf. If 2247 running QEMU as an unprivileged user, an environment variable 2248 SASL\_CONF\_PATH can be used to make it search alternate 2249 locations for the service config. While some SASL auth methods 2250 can also provide data encryption (eg GSSAPI), it is recommended 2251 that SASL always be combined with the 'tls' and 'x509' settings 2252 to enable use of SSL and server certificates. This ensures a 2253 data encryption preventing compromise of authentication 2254 credentials. 2255 2256 ``disable-ticketing=on|off`` 2257 Allow client connects without authentication. 2258 2259 ``disable-copy-paste=on|off`` 2260 Disable copy paste between the client and the guest. 2261 2262 ``disable-agent-file-xfer=on|off`` 2263 Disable spice-vdagent based file-xfer between the client and the 2264 guest. 2265 2266 ``tls-port=<nr>`` 2267 Set the TCP port spice is listening on for encrypted channels. 2268 2269 ``x509-dir=<dir>`` 2270 Set the x509 file directory. Expects same filenames as -vnc 2271 $display,x509=$dir 2272 2273 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2274 The x509 file names can also be configured individually. 2275 2276 ``tls-ciphers=<list>`` 2277 Specify which ciphers to use. 2278 2279 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2280 Force specific channel to be used with or without TLS 2281 encryption. The options can be specified multiple times to 2282 configure multiple channels. The special name "default" can be 2283 used to set the default mode. For channels which are not 2284 explicitly forced into one mode the spice client is allowed to 2285 pick tls/plaintext as he pleases. 2286 2287 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2288 Configure image compression (lossless). Default is auto\_glz. 2289 2290 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2291 Configure wan image compression (lossy for slow links). Default 2292 is auto. 2293 2294 ``streaming-video=[off|all|filter]`` 2295 Configure video stream detection. Default is off. 2296 2297 ``agent-mouse=[on|off]`` 2298 Enable/disable passing mouse events via vdagent. Default is on. 2299 2300 ``playback-compression=[on|off]`` 2301 Enable/disable audio stream compression (using celt 0.5.1). 2302 Default is on. 2303 2304 ``seamless-migration=[on|off]`` 2305 Enable/disable spice seamless migration. Default is off. 2306 2307 ``gl=[on|off]`` 2308 Enable/disable OpenGL context. Default is off. 2309 2310 ``rendernode=<file>`` 2311 DRM render node for OpenGL rendering. If not specified, it will 2312 pick the first available. (Since 2.9) 2313ERST 2314 2315DEF("portrait", 0, QEMU_OPTION_portrait, 2316 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2317 QEMU_ARCH_ALL) 2318SRST 2319``-portrait`` 2320 Rotate graphical output 90 deg left (only PXA LCD). 2321ERST 2322 2323DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2324 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2325 QEMU_ARCH_ALL) 2326SRST 2327``-rotate deg`` 2328 Rotate graphical output some deg left (only PXA LCD). 2329ERST 2330 2331DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2332 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2333 " select video card type\n", QEMU_ARCH_ALL) 2334SRST 2335``-vga type`` 2336 Select type of VGA card to emulate. Valid values for type are 2337 2338 ``cirrus`` 2339 Cirrus Logic GD5446 Video card. All Windows versions starting 2340 from Windows 95 should recognize and use this graphic card. For 2341 optimal performances, use 16 bit color depth in the guest and 2342 the host OS. (This card was the default before QEMU 2.2) 2343 2344 ``std`` 2345 Standard VGA card with Bochs VBE extensions. If your guest OS 2346 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2347 you want to use high resolution modes (>= 1280x1024x16) then you 2348 should use this option. (This card is the default since QEMU 2349 2.2) 2350 2351 ``vmware`` 2352 VMWare SVGA-II compatible adapter. Use it if you have 2353 sufficiently recent XFree86/XOrg server or Windows guest with a 2354 driver for this card. 2355 2356 ``qxl`` 2357 QXL paravirtual graphic card. It is VGA compatible (including 2358 VESA 2.0 VBE support). Works best with qxl guest drivers 2359 installed though. Recommended choice when using the spice 2360 protocol. 2361 2362 ``tcx`` 2363 (sun4m only) Sun TCX framebuffer. This is the default 2364 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2365 colour depths at a fixed resolution of 1024x768. 2366 2367 ``cg3`` 2368 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2369 framebuffer for sun4m machines available in both 1024x768 2370 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2371 wishing to run older Solaris versions. 2372 2373 ``virtio`` 2374 Virtio VGA card. 2375 2376 ``none`` 2377 Disable VGA card. 2378ERST 2379 2380DEF("full-screen", 0, QEMU_OPTION_full_screen, 2381 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2382SRST 2383``-full-screen`` 2384 Start in full screen. 2385ERST 2386 2387DEF("g", HAS_ARG, QEMU_OPTION_g , 2388 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2389 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2390SRST 2391``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2392 Set the initial graphical resolution and depth (PPC, SPARC only). 2393 2394 For PPC the default is 800x600x32. 2395 2396 For SPARC with the TCX graphics device, the default is 1024x768x8 2397 with the option of 1024x768x24. For cgthree, the default is 2398 1024x768x8 with the option of 1152x900x8 for people who wish to use 2399 OBP. 2400ERST 2401 2402DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2403 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2404SRST 2405``-vnc display[,option[,option[,...]]]`` 2406 Normally, if QEMU is compiled with graphical window support, it 2407 displays output such as guest graphics, guest console, and the QEMU 2408 monitor in a window. With this option, you can have QEMU listen on 2409 VNC display display and redirect the VGA display over the VNC 2410 session. It is very useful to enable the usb tablet device when 2411 using this option (option ``-device usb-tablet``). When using the 2412 VNC display, you must use the ``-k`` parameter to set the keyboard 2413 layout if you are not using en-us. Valid syntax for the display is 2414 2415 ``to=L`` 2416 With this option, QEMU will try next available VNC displays, 2417 until the number L, if the origianlly defined "-vnc display" is 2418 not available, e.g. port 5900+display is already used by another 2419 application. By default, to=0. 2420 2421 ``host:d`` 2422 TCP connections will only be allowed from host on display d. By 2423 convention the TCP port is 5900+d. Optionally, host can be 2424 omitted in which case the server will accept connections from 2425 any host. 2426 2427 ``unix:path`` 2428 Connections will be allowed over UNIX domain sockets where path 2429 is the location of a unix socket to listen for connections on. 2430 2431 ``none`` 2432 VNC is initialized but not started. The monitor ``change`` 2433 command can be used to later start the VNC server. 2434 2435 Following the display value there may be one or more option flags 2436 separated by commas. Valid options are 2437 2438 ``reverse=on|off`` 2439 Connect to a listening VNC client via a "reverse" connection. 2440 The client is specified by the display. For reverse network 2441 connections (host:d,``reverse``), the d argument is a TCP port 2442 number, not a display number. 2443 2444 ``websocket=on|off`` 2445 Opens an additional TCP listening port dedicated to VNC 2446 Websocket connections. If a bare websocket option is given, the 2447 Websocket port is 5700+display. An alternative port can be 2448 specified with the syntax ``websocket``\ =port. 2449 2450 If host is specified connections will only be allowed from this 2451 host. It is possible to control the websocket listen address 2452 independently, using the syntax ``websocket``\ =host:port. 2453 2454 If no TLS credentials are provided, the websocket connection 2455 runs in unencrypted mode. If TLS credentials are provided, the 2456 websocket connection requires encrypted client connections. 2457 2458 ``password=on|off`` 2459 Require that password based authentication is used for client 2460 connections. 2461 2462 The password must be set separately using the ``set_password`` 2463 command in the :ref:`QEMU monitor`. The 2464 syntax to change your password is: 2465 ``set_password <protocol> <password>`` where <protocol> could be 2466 either "vnc" or "spice". 2467 2468 If you would like to change <protocol> password expiration, you 2469 should use ``expire_password <protocol> <expiration-time>`` 2470 where expiration time could be one of the following options: 2471 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2472 make password expire in 60 seconds, or 1335196800 to make 2473 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2474 this date and time). 2475 2476 You can also use keywords "now" or "never" for the expiration 2477 time to allow <protocol> password to expire immediately or never 2478 expire. 2479 2480 ``password-secret=<secret-id>`` 2481 Require that password based authentication is used for client 2482 connections, using the password provided by the ``secret`` 2483 object identified by ``secret-id``. 2484 2485 ``tls-creds=ID`` 2486 Provides the ID of a set of TLS credentials to use to secure the 2487 VNC server. They will apply to both the normal VNC server socket 2488 and the websocket socket (if enabled). Setting TLS credentials 2489 will cause the VNC server socket to enable the VeNCrypt auth 2490 mechanism. The credentials should have been previously created 2491 using the ``-object tls-creds`` argument. 2492 2493 ``tls-authz=ID`` 2494 Provides the ID of the QAuthZ authorization object against which 2495 the client's x509 distinguished name will validated. This object 2496 is only resolved at time of use, so can be deleted and recreated 2497 on the fly while the VNC server is active. If missing, it will 2498 default to denying access. 2499 2500 ``sasl=on|off`` 2501 Require that the client use SASL to authenticate with the VNC 2502 server. The exact choice of authentication method used is 2503 controlled from the system / user's SASL configuration file for 2504 the 'qemu' service. This is typically found in 2505 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2506 an environment variable SASL\_CONF\_PATH can be used to make it 2507 search alternate locations for the service config. While some 2508 SASL auth methods can also provide data encryption (eg GSSAPI), 2509 it is recommended that SASL always be combined with the 'tls' 2510 and 'x509' settings to enable use of SSL and server 2511 certificates. This ensures a data encryption preventing 2512 compromise of authentication credentials. See the 2513 :ref:`VNC security` section in the System Emulation Users Guide 2514 for details on using SASL authentication. 2515 2516 ``sasl-authz=ID`` 2517 Provides the ID of the QAuthZ authorization object against which 2518 the client's SASL username will validated. This object is only 2519 resolved at time of use, so can be deleted and recreated on the 2520 fly while the VNC server is active. If missing, it will default 2521 to denying access. 2522 2523 ``acl=on|off`` 2524 Legacy method for enabling authorization of clients against the 2525 x509 distinguished name and SASL username. It results in the 2526 creation of two ``authz-list`` objects with IDs of 2527 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2528 objects must be configured with the HMP ACL commands. 2529 2530 This option is deprecated and should no longer be used. The new 2531 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2532 2533 ``lossy=on|off`` 2534 Enable lossy compression methods (gradient, JPEG, ...). If this 2535 option is set, VNC client may receive lossy framebuffer updates 2536 depending on its encoding settings. Enabling this option can 2537 save a lot of bandwidth at the expense of quality. 2538 2539 ``non-adaptive=on|off`` 2540 Disable adaptive encodings. Adaptive encodings are enabled by 2541 default. An adaptive encoding will try to detect frequently 2542 updated screen regions, and send updates in these regions using 2543 a lossy encoding (like JPEG). This can be really helpful to save 2544 bandwidth when playing videos. Disabling adaptive encodings 2545 restores the original static behavior of encodings like Tight. 2546 2547 ``share=[allow-exclusive|force-shared|ignore]`` 2548 Set display sharing policy. 'allow-exclusive' allows clients to 2549 ask for exclusive access. As suggested by the rfb spec this is 2550 implemented by dropping other connections. Connecting multiple 2551 clients in parallel requires all clients asking for a shared 2552 session (vncviewer: -shared switch). This is the default. 2553 'force-shared' disables exclusive client access. Useful for 2554 shared desktop sessions, where you don't want someone forgetting 2555 specify -shared disconnect everybody else. 'ignore' completely 2556 ignores the shared flag and allows everybody connect 2557 unconditionally. Doesn't conform to the rfb spec but is 2558 traditional QEMU behavior. 2559 2560 ``key-delay-ms`` 2561 Set keyboard delay, for key down and key up events, in 2562 milliseconds. Default is 10. Keyboards are low-bandwidth 2563 devices, so this slowdown can help the device and guest to keep 2564 up and not lose events in case events are arriving in bulk. 2565 Possible causes for the latter are flaky network connections, or 2566 scripts for automated testing. 2567 2568 ``audiodev=audiodev`` 2569 Use the specified audiodev when the VNC client requests audio 2570 transmission. When not using an -audiodev argument, this option 2571 must be omitted, otherwise is must be present and specify a 2572 valid audiodev. 2573 2574 ``power-control=on|off`` 2575 Permit the remote client to issue shutdown, reboot or reset power 2576 control requests. 2577ERST 2578 2579ARCHHEADING(, QEMU_ARCH_I386) 2580 2581ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2582 2583DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2584 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2585 QEMU_ARCH_I386) 2586SRST 2587``-win2k-hack`` 2588 Use it when installing Windows 2000 to avoid a disk full bug. After 2589 Windows 2000 is installed, you no longer need this option (this 2590 option slows down the IDE transfers). 2591ERST 2592 2593DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2594 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2595 QEMU_ARCH_I386) 2596SRST 2597``-no-fd-bootchk`` 2598 Disable boot signature checking for floppy disks in BIOS. May be 2599 needed to boot from old floppy disks. 2600ERST 2601 2602DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2603 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2604SRST 2605``-no-acpi`` 2606 Disable ACPI (Advanced Configuration and Power Interface) support. 2607 Use it if your guest OS complains about ACPI problems (PC target 2608 machine only). 2609ERST 2610 2611DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2612 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2613SRST 2614``-no-hpet`` 2615 Disable HPET support. Deprecated, use '-machine hpet=off' instead. 2616ERST 2617 2618DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2619 "-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" 2620 " ACPI table description\n", QEMU_ARCH_I386) 2621SRST 2622``-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]...]`` 2623 Add ACPI table with specified header fields and context from 2624 specified files. For file=, take whole ACPI table from the specified 2625 files, including all ACPI headers (possible overridden by other 2626 options). For data=, only data portion of the table is used, all 2627 header information is specified in the command line. If a SLIC table 2628 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2629 fields will override the same in the RSDT and the FADT (a.k.a. 2630 FACP), in order to ensure the field matches required by the 2631 Microsoft SLIC spec and the ACPI spec. 2632ERST 2633 2634DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2635 "-smbios file=binary\n" 2636 " load SMBIOS entry from binary file\n" 2637 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2638 " [,uefi=on|off]\n" 2639 " specify SMBIOS type 0 fields\n" 2640 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2641 " [,uuid=uuid][,sku=str][,family=str]\n" 2642 " specify SMBIOS type 1 fields\n" 2643 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2644 " [,asset=str][,location=str]\n" 2645 " specify SMBIOS type 2 fields\n" 2646 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2647 " [,sku=str]\n" 2648 " specify SMBIOS type 3 fields\n" 2649 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2650 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2651 " [,processor-id=%d]\n" 2652 " specify SMBIOS type 4 fields\n" 2653 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2654 " specify SMBIOS type 8 fields\n" 2655 "-smbios type=11[,value=str][,path=filename]\n" 2656 " specify SMBIOS type 11 fields\n" 2657 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2658 " [,asset=str][,part=str][,speed=%d]\n" 2659 " specify SMBIOS type 17 fields\n" 2660 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2661 " specify SMBIOS type 41 fields\n", 2662 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2663SRST 2664``-smbios file=binary`` 2665 Load SMBIOS entry from binary file. 2666 2667``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2668 Specify SMBIOS type 0 fields 2669 2670``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2671 Specify SMBIOS type 1 fields 2672 2673``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2674 Specify SMBIOS type 2 fields 2675 2676``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2677 Specify SMBIOS type 3 fields 2678 2679``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2680 Specify SMBIOS type 4 fields 2681 2682``-smbios type=11[,value=str][,path=filename]`` 2683 Specify SMBIOS type 11 fields 2684 2685 This argument can be repeated multiple times, and values are added in the order they are parsed. 2686 Applications intending to use OEM strings data are encouraged to use their application name as 2687 a prefix for the value string. This facilitates passing information for multiple applications 2688 concurrently. 2689 2690 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2691 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2692 2693 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2694 the SMBIOS table in the order in which they appear. 2695 2696 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2697 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2698 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2699 data set, for example, by specifying the serial ID of a block device. 2700 2701 An example passing three strings is 2702 2703 .. parsed-literal:: 2704 2705 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2706 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2707 path=/some/file/with/oemstringsdata.txt 2708 2709 In the guest OS this is visible with the ``dmidecode`` command 2710 2711 .. parsed-literal:: 2712 2713 $ dmidecode -t 11 2714 Handle 0x0E00, DMI type 11, 5 bytes 2715 OEM Strings 2716 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2717 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2718 String 3: myapp:some extra data 2719 2720 2721``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2722 Specify SMBIOS type 17 fields 2723 2724``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2725 Specify SMBIOS type 41 fields 2726 2727 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2728 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2729 position on the PCI bus. 2730 2731 Here is an example of use: 2732 2733 .. parsed-literal:: 2734 2735 -netdev user,id=internet \\ 2736 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2737 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2738 2739 In the guest OS, the device should then appear as ``eno1``: 2740 2741 ..parsed-literal:: 2742 2743 $ ip -brief l 2744 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2745 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2746 2747 Currently, the PCI device has to be attached to the root bus. 2748 2749ERST 2750 2751DEFHEADING() 2752 2753DEFHEADING(Network options:) 2754 2755DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2756#ifdef CONFIG_SLIRP 2757 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2758 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2759 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2760 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2761 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2762#ifndef _WIN32 2763 "[,smb=dir[,smbserver=addr]]\n" 2764#endif 2765 " configure a user mode network backend with ID 'str',\n" 2766 " its DHCP server and optional services\n" 2767#endif 2768#ifdef _WIN32 2769 "-netdev tap,id=str,ifname=name\n" 2770 " configure a host TAP network backend with ID 'str'\n" 2771#else 2772 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2773 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2774 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2775 " [,poll-us=n]\n" 2776 " configure a host TAP network backend with ID 'str'\n" 2777 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2778 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2779 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2780 " to deconfigure it\n" 2781 " use '[down]script=no' to disable script execution\n" 2782 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2783 " configure it\n" 2784 " use 'fd=h' to connect to an already opened TAP interface\n" 2785 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2786 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2787 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2788 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2789 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2790 " use vhost=on to enable experimental in kernel accelerator\n" 2791 " (only has effect for virtio guests which use MSIX)\n" 2792 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2793 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2794 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2795 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2796 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2797 " spent on busy polling for vhost net\n" 2798 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2799 " configure a host TAP network backend with ID 'str' that is\n" 2800 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2801 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2802#endif 2803#ifdef __linux__ 2804 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2805 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2806 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2807 " [,rxcookie=rxcookie][,offset=offset]\n" 2808 " configure a network backend with ID 'str' connected to\n" 2809 " an Ethernet over L2TPv3 pseudowire.\n" 2810 " Linux kernel 3.3+ as well as most routers can talk\n" 2811 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2812 " VM to a router and even VM to Host. It is a nearly-universal\n" 2813 " standard (RFC3931). Note - this implementation uses static\n" 2814 " pre-configured tunnels (same as the Linux kernel).\n" 2815 " use 'src=' to specify source address\n" 2816 " use 'dst=' to specify destination address\n" 2817 " use 'udp=on' to specify udp encapsulation\n" 2818 " use 'srcport=' to specify source udp port\n" 2819 " use 'dstport=' to specify destination udp port\n" 2820 " use 'ipv6=on' to force v6\n" 2821 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2822 " well as a weak security measure\n" 2823 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2824 " use 'txcookie=0x012345678' to specify a txcookie\n" 2825 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2826 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2827 " use 'pincounter=on' to work around broken counter handling in peer\n" 2828 " use 'offset=X' to add an extra offset between header and data\n" 2829#endif 2830 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2831 " configure a network backend to connect to another network\n" 2832 " using a socket connection\n" 2833 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2834 " configure a network backend to connect to a multicast maddr and port\n" 2835 " use 'localaddr=addr' to specify the host address to send packets from\n" 2836 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2837 " configure a network backend to connect to another network\n" 2838 " using an UDP tunnel\n" 2839 "-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" 2840 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2841 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2842 " configure a network backend to connect to another network\n" 2843 " using a socket connection in stream mode.\n" 2844 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2845 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2846 " configure a network backend to connect to a multicast maddr and port\n" 2847 " use ``local.host=addr`` to specify the host address to send packets from\n" 2848 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2849 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2850 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2851 " configure a network backend to connect to another network\n" 2852 " using an UDP tunnel\n" 2853#ifdef CONFIG_VDE 2854 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2855 " configure a network backend to connect to port 'n' of a vde switch\n" 2856 " running on host and listening for incoming connections on 'socketpath'.\n" 2857 " Use group 'groupname' and mode 'octalmode' to change default\n" 2858 " ownership and permissions for communication port.\n" 2859#endif 2860#ifdef CONFIG_NETMAP 2861 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2862 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2863 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2864 " netmap device, defaults to '/dev/netmap')\n" 2865#endif 2866#ifdef CONFIG_POSIX 2867 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2868 " configure a vhost-user network, backed by a chardev 'dev'\n" 2869#endif 2870#ifdef __linux__ 2871 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2872 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2873 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2874 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2875#endif 2876#ifdef CONFIG_VMNET 2877 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2878 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2879 " configure a vmnet network backend in host mode with ID 'str',\n" 2880 " isolate this interface from others with 'isolated',\n" 2881 " configure the address range and choose a subnet mask,\n" 2882 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2883 " vmnet-host interfaces within this isolated network\n" 2884 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2885 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2886 " configure a vmnet network backend in shared mode with ID 'str',\n" 2887 " configure the address range and choose a subnet mask,\n" 2888 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2889 " isolate this interface from others with 'isolated'\n" 2890 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2891 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2892 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2893 " isolate this interface from others with 'isolated'\n" 2894#endif 2895 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2896 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2897DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2898 "-nic [tap|bridge|" 2899#ifdef CONFIG_SLIRP 2900 "user|" 2901#endif 2902#ifdef __linux__ 2903 "l2tpv3|" 2904#endif 2905#ifdef CONFIG_VDE 2906 "vde|" 2907#endif 2908#ifdef CONFIG_NETMAP 2909 "netmap|" 2910#endif 2911#ifdef CONFIG_POSIX 2912 "vhost-user|" 2913#endif 2914#ifdef CONFIG_VMNET 2915 "vmnet-host|vmnet-shared|vmnet-bridged|" 2916#endif 2917 "socket][,option][,...][mac=macaddr]\n" 2918 " initialize an on-board / default host NIC (using MAC address\n" 2919 " macaddr) and connect it to the given host network backend\n" 2920 "-nic none use it alone to have zero network devices (the default is to\n" 2921 " provided a 'user' network connection)\n", 2922 QEMU_ARCH_ALL) 2923DEF("net", HAS_ARG, QEMU_OPTION_net, 2924 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2925 " configure or create an on-board (or machine default) NIC and\n" 2926 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2927 "-net [" 2928#ifdef CONFIG_SLIRP 2929 "user|" 2930#endif 2931 "tap|" 2932 "bridge|" 2933#ifdef CONFIG_VDE 2934 "vde|" 2935#endif 2936#ifdef CONFIG_NETMAP 2937 "netmap|" 2938#endif 2939#ifdef CONFIG_VMNET 2940 "vmnet-host|vmnet-shared|vmnet-bridged|" 2941#endif 2942 "socket][,option][,option][,...]\n" 2943 " old way to initialize a host network interface\n" 2944 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2945SRST 2946``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2947 This option is a shortcut for configuring both the on-board 2948 (default) guest NIC hardware and the host network backend in one go. 2949 The host backend options are the same as with the corresponding 2950 ``-netdev`` options below. The guest NIC model can be set with 2951 ``model=modelname``. Use ``model=help`` to list the available device 2952 types. The hardware MAC address can be set with ``mac=macaddr``. 2953 2954 The following two example do exactly the same, to show how ``-nic`` 2955 can be used to shorten the command line length: 2956 2957 .. parsed-literal:: 2958 2959 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2960 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2961 2962``-nic none`` 2963 Indicate that no network devices should be configured. It is used to 2964 override the default configuration (default NIC with "user" host 2965 network backend) which is activated if no other networking options 2966 are provided. 2967 2968``-netdev user,id=id[,option][,option][,...]`` 2969 Configure user mode host network backend which requires no 2970 administrator privilege to run. Valid options are: 2971 2972 ``id=id`` 2973 Assign symbolic name for use in monitor commands. 2974 2975 ``ipv4=on|off and ipv6=on|off`` 2976 Specify that either IPv4 or IPv6 must be enabled. If neither is 2977 specified both protocols are enabled. 2978 2979 ``net=addr[/mask]`` 2980 Set IP network address the guest will see. Optionally specify 2981 the netmask, either in the form a.b.c.d or as number of valid 2982 top-most bits. Default is 10.0.2.0/24. 2983 2984 ``host=addr`` 2985 Specify the guest-visible address of the host. Default is the 2986 2nd IP in the guest network, i.e. x.x.x.2. 2987 2988 ``ipv6-net=addr[/int]`` 2989 Set IPv6 network address the guest will see (default is 2990 fec0::/64). The network prefix is given in the usual hexadecimal 2991 IPv6 address notation. The prefix size is optional, and is given 2992 as the number of valid top-most bits (default is 64). 2993 2994 ``ipv6-host=addr`` 2995 Specify the guest-visible IPv6 address of the host. Default is 2996 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2997 2998 ``restrict=on|off`` 2999 If this option is enabled, the guest will be isolated, i.e. it 3000 will not be able to contact the host and no guest IP packets 3001 will be routed over the host to the outside. This option does 3002 not affect any explicitly set forwarding rules. 3003 3004 ``hostname=name`` 3005 Specifies the client hostname reported by the built-in DHCP 3006 server. 3007 3008 ``dhcpstart=addr`` 3009 Specify the first of the 16 IPs the built-in DHCP server can 3010 assign. Default is the 15th to 31st IP in the guest network, 3011 i.e. x.x.x.15 to x.x.x.31. 3012 3013 ``dns=addr`` 3014 Specify the guest-visible address of the virtual nameserver. The 3015 address must be different from the host address. Default is the 3016 3rd IP in the guest network, i.e. x.x.x.3. 3017 3018 ``ipv6-dns=addr`` 3019 Specify the guest-visible address of the IPv6 virtual 3020 nameserver. The address must be different from the host address. 3021 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3022 3023 ``dnssearch=domain`` 3024 Provides an entry for the domain-search list sent by the 3025 built-in DHCP server. More than one domain suffix can be 3026 transmitted by specifying this option multiple times. If 3027 supported, this will cause the guest to automatically try to 3028 append the given domain suffix(es) in case a domain name can not 3029 be resolved. 3030 3031 Example: 3032 3033 .. parsed-literal:: 3034 3035 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3036 3037 ``domainname=domain`` 3038 Specifies the client domain name reported by the built-in DHCP 3039 server. 3040 3041 ``tftp=dir`` 3042 When using the user mode network stack, activate a built-in TFTP 3043 server. The files in dir will be exposed as the root of a TFTP 3044 server. The TFTP client on the guest must be configured in 3045 binary mode (use the command ``bin`` of the Unix TFTP client). 3046 3047 ``tftp-server-name=name`` 3048 In BOOTP reply, broadcast name as the "TFTP server name" 3049 (RFC2132 option 66). This can be used to advise the guest to 3050 load boot files or configurations from a different server than 3051 the host address. 3052 3053 ``bootfile=file`` 3054 When using the user mode network stack, broadcast file as the 3055 BOOTP filename. In conjunction with ``tftp``, this can be used 3056 to network boot a guest from a local directory. 3057 3058 Example (using pxelinux): 3059 3060 .. parsed-literal:: 3061 3062 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3063 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3064 3065 ``smb=dir[,smbserver=addr]`` 3066 When using the user mode network stack, activate a built-in SMB 3067 server so that Windows OSes can access to the host files in 3068 ``dir`` transparently. The IP address of the SMB server can be 3069 set to addr. By default the 4th IP in the guest network is used, 3070 i.e. x.x.x.4. 3071 3072 In the guest Windows OS, the line: 3073 3074 :: 3075 3076 10.0.2.4 smbserver 3077 3078 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3079 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3080 NT/2000). 3081 3082 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3083 3084 Note that a SAMBA server must be installed on the host OS. 3085 3086 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3087 Redirect incoming TCP or UDP connections to the host port 3088 hostport to the guest IP address guestaddr on guest port 3089 guestport. If guestaddr is not specified, its value is x.x.x.15 3090 (default first address given by the built-in DHCP server). By 3091 specifying hostaddr, the rule can be bound to a specific host 3092 interface. If no connection type is set, TCP is used. This 3093 option can be given multiple times. 3094 3095 For example, to redirect host X11 connection from screen 1 to 3096 guest screen 0, use the following: 3097 3098 .. parsed-literal:: 3099 3100 # on the host 3101 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3102 # this host xterm should open in the guest X11 server 3103 xterm -display :1 3104 3105 To redirect telnet connections from host port 5555 to telnet 3106 port on the guest, use the following: 3107 3108 .. parsed-literal:: 3109 3110 # on the host 3111 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3112 telnet localhost 5555 3113 3114 Then when you use on the host ``telnet localhost 5555``, you 3115 connect to the guest telnet server. 3116 3117 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3118 Forward guest TCP connections to the IP address server on port 3119 port to the character device dev or to a program executed by 3120 cmd:command which gets spawned for each connection. This option 3121 can be given multiple times. 3122 3123 You can either use a chardev directly and have that one used 3124 throughout QEMU's lifetime, like in the following example: 3125 3126 .. parsed-literal:: 3127 3128 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3129 # the guest accesses it 3130 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3131 3132 Or you can execute a command on every TCP connection established 3133 by the guest, so that QEMU behaves similar to an inetd process 3134 for that virtual server: 3135 3136 .. parsed-literal:: 3137 3138 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3139 # and connect the TCP stream to its stdin/stdout 3140 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3141 3142``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3143 Configure a host TAP network backend with ID id. 3144 3145 Use the network script file to configure it and the network script 3146 dfile to deconfigure it. If name is not provided, the OS 3147 automatically provides one. The default network configure script is 3148 ``/etc/qemu-ifup`` and the default network deconfigure script is 3149 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3150 disable script execution. 3151 3152 If running QEMU as an unprivileged user, use the network helper 3153 to configure the TAP interface and attach it to the bridge. 3154 The default network helper executable is 3155 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3156 ``br0``. 3157 3158 ``fd``\ =h can be used to specify the handle of an already opened 3159 host TAP interface. 3160 3161 Examples: 3162 3163 .. parsed-literal:: 3164 3165 #launch a QEMU instance with the default network script 3166 |qemu_system| linux.img -nic tap 3167 3168 .. parsed-literal:: 3169 3170 #launch a QEMU instance with two NICs, each one connected 3171 #to a TAP device 3172 |qemu_system| linux.img \\ 3173 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3174 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3175 3176 .. parsed-literal:: 3177 3178 #launch a QEMU instance with the default network helper to 3179 #connect a TAP device to bridge br0 3180 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3181 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3182 3183``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3184 Connect a host TAP network interface to a host bridge device. 3185 3186 Use the network helper helper to configure the TAP interface and 3187 attach it to the bridge. The default network helper executable is 3188 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3189 ``br0``. 3190 3191 Examples: 3192 3193 .. parsed-literal:: 3194 3195 #launch a QEMU instance with the default network helper to 3196 #connect a TAP device to bridge br0 3197 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3198 3199 .. parsed-literal:: 3200 3201 #launch a QEMU instance with the default network helper to 3202 #connect a TAP device to bridge qemubr0 3203 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3204 3205``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3206 This host network backend can be used to connect the guest's network 3207 to another QEMU virtual machine using a TCP socket connection. If 3208 ``listen`` is specified, QEMU waits for incoming connections on port 3209 (host is optional). ``connect`` is used to connect to another QEMU 3210 instance using the ``listen`` option. ``fd``\ =h specifies an 3211 already opened TCP socket. 3212 3213 Example: 3214 3215 .. parsed-literal:: 3216 3217 # launch a first QEMU instance 3218 |qemu_system| linux.img \\ 3219 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3220 -netdev socket,id=n1,listen=:1234 3221 # connect the network of this instance to the network of the first instance 3222 |qemu_system| linux.img \\ 3223 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3224 -netdev socket,id=n2,connect=127.0.0.1:1234 3225 3226``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3227 Configure a socket host network backend to share the guest's network 3228 traffic with another QEMU virtual machines using a UDP multicast 3229 socket, effectively making a bus for every QEMU with same multicast 3230 address maddr and port. NOTES: 3231 3232 1. Several QEMU can be running on different hosts and share same bus 3233 (assuming correct multicast setup for these hosts). 3234 3235 2. mcast support is compatible with User Mode Linux (argument 3236 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3237 3238 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3239 3240 Example: 3241 3242 .. parsed-literal:: 3243 3244 # launch one QEMU instance 3245 |qemu_system| linux.img \\ 3246 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3247 -netdev socket,id=n1,mcast=230.0.0.1:1234 3248 # launch another QEMU instance on same "bus" 3249 |qemu_system| linux.img \\ 3250 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3251 -netdev socket,id=n2,mcast=230.0.0.1:1234 3252 # launch yet another QEMU instance on same "bus" 3253 |qemu_system| linux.img \\ 3254 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3255 -netdev socket,id=n3,mcast=230.0.0.1:1234 3256 3257 Example (User Mode Linux compat.): 3258 3259 .. parsed-literal:: 3260 3261 # launch QEMU instance (note mcast address selected is UML's default) 3262 |qemu_system| linux.img \\ 3263 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3264 -netdev socket,id=n1,mcast=239.192.168.1:1102 3265 # launch UML 3266 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3267 3268 Example (send packets from host's 1.2.3.4): 3269 3270 .. parsed-literal:: 3271 3272 |qemu_system| linux.img \\ 3273 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3274 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3275 3276``-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]`` 3277 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3278 is a popular protocol to transport Ethernet (and other Layer 2) data 3279 frames between two systems. It is present in routers, firewalls and 3280 the Linux kernel (from version 3.3 onwards). 3281 3282 This transport allows a VM to communicate to another VM, router or 3283 firewall directly. 3284 3285 ``src=srcaddr`` 3286 source address (mandatory) 3287 3288 ``dst=dstaddr`` 3289 destination address (mandatory) 3290 3291 ``udp`` 3292 select udp encapsulation (default is ip). 3293 3294 ``srcport=srcport`` 3295 source udp port. 3296 3297 ``dstport=dstport`` 3298 destination udp port. 3299 3300 ``ipv6`` 3301 force v6, otherwise defaults to v4. 3302 3303 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3304 Cookies are a weak form of security in the l2tpv3 specification. 3305 Their function is mostly to prevent misconfiguration. By default 3306 they are 32 bit. 3307 3308 ``cookie64`` 3309 Set cookie size to 64 bit instead of the default 32 3310 3311 ``counter=off`` 3312 Force a 'cut-down' L2TPv3 with no counter as in 3313 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3314 3315 ``pincounter=on`` 3316 Work around broken counter handling in peer. This may also help 3317 on networks which have packet reorder. 3318 3319 ``offset=offset`` 3320 Add an extra offset between header and data 3321 3322 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3323 the bridge br-lan on the remote Linux host 1.2.3.4: 3324 3325 .. parsed-literal:: 3326 3327 # Setup tunnel on linux host using raw ip as encapsulation 3328 # on 1.2.3.4 3329 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3330 encap udp udp_sport 16384 udp_dport 16384 3331 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3332 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3333 ifconfig vmtunnel0 mtu 1500 3334 ifconfig vmtunnel0 up 3335 brctl addif br-lan vmtunnel0 3336 3337 3338 # on 4.3.2.1 3339 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3340 3341 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3342 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3343 3344``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3345 Configure VDE backend to connect to PORT n of a vde switch running 3346 on host and listening for incoming connections on socketpath. Use 3347 GROUP groupname and MODE octalmode to change default ownership and 3348 permissions for communication port. This option is only available if 3349 QEMU has been compiled with vde support enabled. 3350 3351 Example: 3352 3353 .. parsed-literal:: 3354 3355 # launch vde switch 3356 vde_switch -F -sock /tmp/myswitch 3357 # launch QEMU instance 3358 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3359 3360``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3361 Establish a vhost-user netdev, backed by a chardev id. The chardev 3362 should be a unix domain socket backed one. The vhost-user uses a 3363 specifically defined protocol to pass vhost ioctl replacement 3364 messages to an application on the other end of the socket. On 3365 non-MSIX guests, the feature can be forced with vhostforce. Use 3366 'queues=n' to specify the number of queues to be created for 3367 multiqueue vhost-user. 3368 3369 Example: 3370 3371 :: 3372 3373 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3374 -numa node,memdev=mem \ 3375 -chardev socket,id=chr0,path=/path/to/socket \ 3376 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3377 -device virtio-net-pci,netdev=net0 3378 3379``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3380 Establish a vhost-vdpa netdev. 3381 3382 vDPA device is a device that uses a datapath which complies with 3383 the virtio specifications with a vendor specific control path. 3384 vDPA devices can be both physically located on the hardware or 3385 emulated by software. 3386 3387``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3388 Create a hub port on the emulated hub with ID hubid. 3389 3390 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3391 instead of a single netdev. Alternatively, you can also connect the 3392 hubport to another netdev with ID nd by using the ``netdev=nd`` 3393 option. 3394 3395``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3396 Legacy option to configure or create an on-board (or machine 3397 default) Network Interface Card(NIC) and connect it either to the 3398 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3399 If model is omitted, then the default NIC model associated with the 3400 machine type is used. Note that the default NIC model may change in 3401 future QEMU releases, so it is highly recommended to always specify 3402 a model. Optionally, the MAC address can be changed to mac, the 3403 device address set to addr (PCI cards only), and a name can be 3404 assigned for use in monitor commands. Optionally, for PCI cards, you 3405 can specify the number v of MSI-X vectors that the card should have; 3406 this option currently only affects virtio cards; set v = 0 to 3407 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3408 created. QEMU can emulate several different models of network card. 3409 Use ``-net nic,model=help`` for a list of available devices for your 3410 target. 3411 3412``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3413 Configure a host network backend (with the options corresponding to 3414 the same ``-netdev`` option) and connect it to the emulated hub 0 3415 (the default hub). Use name to specify the name of the hub port. 3416ERST 3417 3418DEFHEADING() 3419 3420DEFHEADING(Character device options:) 3421 3422DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3423 "-chardev help\n" 3424 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3425 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3426 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3427 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3428 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3429 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3430 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3431 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3432 " [,logfile=PATH][,logappend=on|off]\n" 3433 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3434 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3435 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3436 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3437 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3438 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3439#ifdef _WIN32 3440 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3441 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3442#else 3443 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3444 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3445#endif 3446#ifdef CONFIG_BRLAPI 3447 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3448#endif 3449#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3450 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3451 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3452#endif 3453#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3454 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3455#endif 3456#if defined(CONFIG_SPICE) 3457 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3458 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3459#endif 3460 , QEMU_ARCH_ALL 3461) 3462 3463SRST 3464The general form of a character device option is: 3465 3466``-chardev backend,id=id[,mux=on|off][,options]`` 3467 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3468 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3469 ``pty``, ``stdio``, ``braille``, ``parallel``, 3470 ``spicevmc``, ``spiceport``. The specific backend will determine the 3471 applicable options. 3472 3473 Use ``-chardev help`` to print all available chardev backend types. 3474 3475 All devices must have an id, which can be any string up to 127 3476 characters long. It is used to uniquely identify this device in 3477 other command line directives. 3478 3479 A character device may be used in multiplexing mode by multiple 3480 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3481 a "1:N" device, and here the "1" end is your specified chardev 3482 backend, and the "N" end is the various parts of QEMU that can talk 3483 to a chardev. If you create a chardev with ``id=myid`` and 3484 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3485 and you can then configure multiple front ends to use that chardev 3486 ID for their input/output. Up to four different front ends can be 3487 connected to a single multiplexed chardev. (Without multiplexing 3488 enabled, a chardev can only be used by a single front end.) For 3489 instance you could use this to allow a single stdio chardev to be 3490 used by two serial ports and the QEMU monitor: 3491 3492 :: 3493 3494 -chardev stdio,mux=on,id=char0 \ 3495 -mon chardev=char0,mode=readline \ 3496 -serial chardev:char0 \ 3497 -serial chardev:char0 3498 3499 You can have more than one multiplexer in a system configuration; 3500 for instance you could have a TCP port multiplexed between UART 0 3501 and UART 1, and stdio multiplexed between the QEMU monitor and a 3502 parallel port: 3503 3504 :: 3505 3506 -chardev stdio,mux=on,id=char0 \ 3507 -mon chardev=char0,mode=readline \ 3508 -parallel chardev:char0 \ 3509 -chardev tcp,...,mux=on,id=char1 \ 3510 -serial chardev:char1 \ 3511 -serial chardev:char1 3512 3513 When you're using a multiplexed character device, some escape 3514 sequences are interpreted in the input. See the chapter about 3515 :ref:`keys in the character backend multiplexer` in the 3516 System Emulation Users Guide for more details. 3517 3518 Note that some other command line options may implicitly create 3519 multiplexed character backends; for instance ``-serial mon:stdio`` 3520 creates a multiplexed stdio backend connected to the serial port and 3521 the QEMU monitor, and ``-nographic`` also multiplexes the console 3522 and the monitor to stdio. 3523 3524 There is currently no support for multiplexing in the other 3525 direction (where a single QEMU front end takes input and output from 3526 multiple chardevs). 3527 3528 Every backend supports the ``logfile`` option, which supplies the 3529 path to a file to record all data transmitted via the backend. The 3530 ``logappend`` option controls whether the log file will be truncated 3531 or appended to when opened. 3532 3533The available backends are: 3534 3535``-chardev null,id=id`` 3536 A void device. This device will not emit any data, and will drop any 3537 data it receives. The null backend does not take any options. 3538 3539``-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]`` 3540 Create a two-way stream socket, which can be either a TCP or a unix 3541 socket. A unix socket will be created if ``path`` is specified. 3542 Behaviour is undefined if TCP options are specified for a unix 3543 socket. 3544 3545 ``server=on|off`` specifies that the socket shall be a listening socket. 3546 3547 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3548 to connect to a listening socket. 3549 3550 ``telnet=on|off`` specifies that traffic on the socket should interpret 3551 telnet escape sequences. 3552 3553 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3554 communication. 3555 3556 ``reconnect`` sets the timeout for reconnecting on non-server 3557 sockets when the remote end goes away. qemu will delay this many 3558 seconds and then attempt to reconnect. Zero disables reconnecting, 3559 and is the default. 3560 3561 ``tls-creds`` requests enablement of the TLS protocol for 3562 encryption, and specifies the id of the TLS credentials to use for 3563 the handshake. The credentials must be previously created with the 3564 ``-object tls-creds`` argument. 3565 3566 ``tls-auth`` provides the ID of the QAuthZ authorization object 3567 against which the client's x509 distinguished name will be 3568 validated. This object is only resolved at time of use, so can be 3569 deleted and recreated on the fly while the chardev server is active. 3570 If missing, it will default to denying access. 3571 3572 TCP and unix socket options are given below: 3573 3574 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3575 ``host`` for a listening socket specifies the local address to 3576 be bound. For a connecting socket species the remote host to 3577 connect to. ``host`` is optional for listening sockets. If not 3578 specified it defaults to ``0.0.0.0``. 3579 3580 ``port`` for a listening socket specifies the local port to be 3581 bound. For a connecting socket specifies the port on the remote 3582 host to connect to. ``port`` can be given as either a port 3583 number or a service name. ``port`` is required. 3584 3585 ``to`` is only relevant to listening sockets. If it is 3586 specified, and ``port`` cannot be bound, QEMU will attempt to 3587 bind to subsequent ports up to and including ``to`` until it 3588 succeeds. ``to`` must be specified as a port number. 3589 3590 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3591 or IPv6 must be used. If neither is specified the socket may 3592 use either protocol. 3593 3594 ``nodelay=on|off`` disables the Nagle algorithm. 3595 3596 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3597 ``path`` specifies the local path of the unix socket. ``path`` 3598 is required. 3599 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3600 rather than the filesystem. Optional, defaults to false. 3601 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3602 rather than the full sun_path length. Optional, defaults to true. 3603 3604``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3605 Sends all traffic from the guest to a remote host over UDP. 3606 3607 ``host`` specifies the remote host to connect to. If not specified 3608 it defaults to ``localhost``. 3609 3610 ``port`` specifies the port on the remote host to connect to. 3611 ``port`` is required. 3612 3613 ``localaddr`` specifies the local address to bind to. If not 3614 specified it defaults to ``0.0.0.0``. 3615 3616 ``localport`` specifies the local port to bind to. If not specified 3617 any available local port will be used. 3618 3619 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3620 If neither is specified the device may use either protocol. 3621 3622``-chardev msmouse,id=id`` 3623 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3624 does not take any options. 3625 3626``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3627 Connect to a QEMU text console. ``vc`` may optionally be given a 3628 specific size. 3629 3630 ``width`` and ``height`` specify the width and height respectively 3631 of the console, in pixels. 3632 3633 ``cols`` and ``rows`` specify that the console be sized to fit a 3634 text console with the given dimensions. 3635 3636``-chardev ringbuf,id=id[,size=size]`` 3637 Create a ring buffer with fixed size ``size``. size must be a power 3638 of two and defaults to ``64K``. 3639 3640``-chardev file,id=id,path=path[,input-path=input-path]`` 3641 Log all traffic received from the guest to a file. 3642 3643 ``path`` specifies the path of the file to be opened. This file will 3644 be created if it does not already exist, and overwritten if it does. 3645 ``path`` is required. 3646 3647 If ``input-path`` is specified, this is the path of a second file 3648 which will be used for input. If ``input-path`` is not specified, 3649 no input will be available from the chardev. 3650 3651 Note that ``input-path`` is not supported on Windows hosts. 3652 3653``-chardev pipe,id=id,path=path`` 3654 Create a two-way connection to the guest. The behaviour differs 3655 slightly between Windows hosts and other hosts: 3656 3657 On Windows, a single duplex pipe will be created at 3658 ``\\.pipe\path``. 3659 3660 On other hosts, 2 pipes will be created called ``path.in`` and 3661 ``path.out``. Data written to ``path.in`` will be received by the 3662 guest. Data written by the guest can be read from ``path.out``. QEMU 3663 will not create these fifos, and requires them to be present. 3664 3665 ``path`` forms part of the pipe path as described above. ``path`` is 3666 required. 3667 3668``-chardev console,id=id`` 3669 Send traffic from the guest to QEMU's standard output. ``console`` 3670 does not take any options. 3671 3672 ``console`` is only available on Windows hosts. 3673 3674``-chardev serial,id=id,path=path`` 3675 Send traffic from the guest to a serial device on the host. 3676 3677 On Unix hosts serial will actually accept any tty device, not only 3678 serial lines. 3679 3680 ``path`` specifies the name of the serial device to open. 3681 3682``-chardev pty,id=id`` 3683 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3684 does not take any options. 3685 3686 ``pty`` is not available on Windows hosts. 3687 3688``-chardev stdio,id=id[,signal=on|off]`` 3689 Connect to standard input and standard output of the QEMU process. 3690 3691 ``signal`` controls if signals are enabled on the terminal, that 3692 includes exiting QEMU with the key sequence Control-c. This option 3693 is enabled by default, use ``signal=off`` to disable it. 3694 3695``-chardev braille,id=id`` 3696 Connect to a local BrlAPI server. ``braille`` does not take any 3697 options. 3698 3699``-chardev parallel,id=id,path=path`` 3700 \ 3701 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3702 hosts. 3703 3704 Connect to a local parallel port. 3705 3706 ``path`` specifies the path to the parallel port device. ``path`` is 3707 required. 3708 3709``-chardev spicevmc,id=id,debug=debug,name=name`` 3710 ``spicevmc`` is only available when spice support is built in. 3711 3712 ``debug`` debug level for spicevmc 3713 3714 ``name`` name of spice channel to connect to 3715 3716 Connect to a spice virtual machine channel, such as vdiport. 3717 3718``-chardev spiceport,id=id,debug=debug,name=name`` 3719 ``spiceport`` is only available when spice support is built in. 3720 3721 ``debug`` debug level for spicevmc 3722 3723 ``name`` name of spice port to connect to 3724 3725 Connect to a spice port, allowing a Spice client to handle the 3726 traffic identified by a name (preferably a fqdn). 3727ERST 3728 3729DEFHEADING() 3730 3731#ifdef CONFIG_TPM 3732DEFHEADING(TPM device options:) 3733 3734DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3735 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3736 " use path to provide path to a character device; default is /dev/tpm0\n" 3737 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3738 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3739 "-tpmdev emulator,id=id,chardev=dev\n" 3740 " configure the TPM device using chardev backend\n", 3741 QEMU_ARCH_ALL) 3742SRST 3743The general form of a TPM device option is: 3744 3745``-tpmdev backend,id=id[,options]`` 3746 The specific backend type will determine the applicable options. The 3747 ``-tpmdev`` option creates the TPM backend and requires a 3748 ``-device`` option that specifies the TPM frontend interface model. 3749 3750 Use ``-tpmdev help`` to print all available TPM backend types. 3751 3752The available backends are: 3753 3754``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3755 (Linux-host only) Enable access to the host's TPM using the 3756 passthrough driver. 3757 3758 ``path`` specifies the path to the host's TPM device, i.e., on a 3759 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3760 default ``/dev/tpm0`` is used. 3761 3762 ``cancel-path`` specifies the path to the host TPM device's sysfs 3763 entry allowing for cancellation of an ongoing TPM command. 3764 ``cancel-path`` is optional and by default QEMU will search for the 3765 sysfs entry to use. 3766 3767 Some notes about using the host's TPM with the passthrough driver: 3768 3769 The TPM device accessed by the passthrough driver must not be used 3770 by any other application on the host. 3771 3772 Since the host's firmware (BIOS/UEFI) has already initialized the 3773 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3774 the TPM again and may therefore not show a TPM-specific menu that 3775 would otherwise allow the user to configure the TPM, e.g., allow the 3776 user to enable/disable or activate/deactivate the TPM. Further, if 3777 TPM ownership is released from within a VM then the host's TPM will 3778 get disabled and deactivated. To enable and activate the TPM again 3779 afterwards, the host has to be rebooted and the user is required to 3780 enter the firmware's menu to enable and activate the TPM. If the TPM 3781 is left disabled and/or deactivated most TPM commands will fail. 3782 3783 To create a passthrough TPM use the following two options: 3784 3785 :: 3786 3787 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3788 3789 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3790 ``tpmdev=tpm0`` in the device option. 3791 3792``-tpmdev emulator,id=id,chardev=dev`` 3793 (Linux-host only) Enable access to a TPM emulator using Unix domain 3794 socket based chardev backend. 3795 3796 ``chardev`` specifies the unique ID of a character device backend 3797 that provides connection to the software TPM server. 3798 3799 To create a TPM emulator backend device with chardev socket backend: 3800 3801 :: 3802 3803 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3804ERST 3805 3806DEFHEADING() 3807 3808#endif 3809 3810DEFHEADING(Boot Image or Kernel specific:) 3811SRST 3812There are broadly 4 ways you can boot a system with QEMU. 3813 3814 - specify a firmware and let it control finding a kernel 3815 - specify a firmware and pass a hint to the kernel to boot 3816 - direct kernel image boot 3817 - manually load files into the guest's address space 3818 3819The third method is useful for quickly testing kernels but as there is 3820no firmware to pass configuration information to the kernel the 3821hardware must either be probeable, the kernel built for the exact 3822configuration or passed some configuration data (e.g. a DTB blob) 3823which tells the kernel what drivers it needs. This exact details are 3824often hardware specific. 3825 3826The final method is the most generic way of loading images into the 3827guest address space and used mostly for ``bare metal`` type 3828development where the reset vectors of the processor are taken into 3829account. 3830 3831ERST 3832 3833SRST 3834 3835For x86 machines and some other architectures ``-bios`` will generally 3836do the right thing with whatever it is given. For other machines the 3837more strict ``-pflash`` option needs an image that is sized for the 3838flash device for the given machine type. 3839 3840Please see the :ref:`system-targets-ref` section of the manual for 3841more detailed documentation. 3842 3843ERST 3844 3845DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3846 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3847SRST 3848``-bios file`` 3849 Set the filename for the BIOS. 3850ERST 3851 3852DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3853 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3854SRST 3855``-pflash file`` 3856 Use file as a parallel flash image. 3857ERST 3858 3859SRST 3860 3861The kernel options were designed to work with Linux kernels although 3862other things (like hypervisors) can be packaged up as a kernel 3863executable image. The exact format of a executable image is usually 3864architecture specific. 3865 3866The way in which the kernel is started (what address it is loaded at, 3867what if any information is passed to it via CPU registers, the state 3868of the hardware when it is started, and so on) is also architecture 3869specific. Typically it follows the specification laid down by the 3870Linux kernel for how kernels for that architecture must be started. 3871 3872ERST 3873 3874DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3875 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3876SRST 3877``-kernel bzImage`` 3878 Use bzImage as kernel image. The kernel can be either a Linux kernel 3879 or in multiboot format. 3880ERST 3881 3882DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3883 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3884SRST 3885``-append cmdline`` 3886 Use cmdline as kernel command line 3887ERST 3888 3889DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3890 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3891SRST 3892``-initrd file`` 3893 Use file as initial ram disk. 3894 3895``-initrd "file1 arg=foo,file2"`` 3896 This syntax is only available with multiboot. 3897 3898 Use file1 and file2 as modules and pass arg=foo as parameter to the 3899 first module. 3900ERST 3901 3902DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3903 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3904SRST 3905``-dtb file`` 3906 Use file as a device tree binary (dtb) image and pass it to the 3907 kernel on boot. 3908ERST 3909 3910SRST 3911 3912Finally you can also manually load images directly into the address 3913space of the guest. This is most useful for developers who already 3914know the layout of their guest and take care to ensure something sane 3915will happen when the reset vector executes. 3916 3917The generic loader can be invoked by using the loader device: 3918 3919``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3920 3921there is also the guest loader which operates in a similar way but 3922tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3923the guest image is: 3924 3925``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3926 3927ERST 3928 3929DEFHEADING() 3930 3931DEFHEADING(Debug/Expert options:) 3932 3933DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3934 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3935 " Policy for handling deprecated management interfaces\n" 3936 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3937 " Policy for handling unstable management interfaces\n", 3938 QEMU_ARCH_ALL) 3939SRST 3940``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3941 Set policy for handling deprecated management interfaces (experimental): 3942 3943 ``deprecated-input=accept`` (default) 3944 Accept deprecated commands and arguments 3945 ``deprecated-input=reject`` 3946 Reject deprecated commands and arguments 3947 ``deprecated-input=crash`` 3948 Crash on deprecated commands and arguments 3949 ``deprecated-output=accept`` (default) 3950 Emit deprecated command results and events 3951 ``deprecated-output=hide`` 3952 Suppress deprecated command results and events 3953 3954 Limitation: covers only syntactic aspects of QMP. 3955 3956``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3957 Set policy for handling unstable management interfaces (experimental): 3958 3959 ``unstable-input=accept`` (default) 3960 Accept unstable commands and arguments 3961 ``unstable-input=reject`` 3962 Reject unstable commands and arguments 3963 ``unstable-input=crash`` 3964 Crash on unstable commands and arguments 3965 ``unstable-output=accept`` (default) 3966 Emit unstable command results and events 3967 ``unstable-output=hide`` 3968 Suppress unstable command results and events 3969 3970 Limitation: covers only syntactic aspects of QMP. 3971ERST 3972 3973DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3974 "-fw_cfg [name=]<name>,file=<file>\n" 3975 " add named fw_cfg entry with contents from file\n" 3976 "-fw_cfg [name=]<name>,string=<str>\n" 3977 " add named fw_cfg entry with contents from string\n", 3978 QEMU_ARCH_ALL) 3979SRST 3980``-fw_cfg [name=]name,file=file`` 3981 Add named fw\_cfg entry with contents from file file. 3982 3983``-fw_cfg [name=]name,string=str`` 3984 Add named fw\_cfg entry with contents from string str. 3985 3986 The terminating NUL character of the contents of str will not be 3987 included as part of the fw\_cfg item data. To insert contents with 3988 embedded NUL characters, you have to use the file parameter. 3989 3990 The fw\_cfg entries are passed by QEMU through to the guest. 3991 3992 Example: 3993 3994 :: 3995 3996 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3997 3998 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3999 from ./my\_blob.bin. 4000ERST 4001 4002DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4003 "-serial dev redirect the serial port to char device 'dev'\n", 4004 QEMU_ARCH_ALL) 4005SRST 4006``-serial dev`` 4007 Redirect the virtual serial port to host character device dev. The 4008 default device is ``vc`` in graphical mode and ``stdio`` in non 4009 graphical mode. 4010 4011 This option can be used several times to simulate up to 4 serial 4012 ports. 4013 4014 Use ``-serial none`` to disable all serial ports. 4015 4016 Available character devices are: 4017 4018 ``vc[:WxH]`` 4019 Virtual console. Optionally, a width and height can be given in 4020 pixel with 4021 4022 :: 4023 4024 vc:800x600 4025 4026 It is also possible to specify width or height in characters: 4027 4028 :: 4029 4030 vc:80Cx24C 4031 4032 ``pty`` 4033 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4034 4035 ``none`` 4036 No device is allocated. 4037 4038 ``null`` 4039 void device 4040 4041 ``chardev:id`` 4042 Use a named character device defined with the ``-chardev`` 4043 option. 4044 4045 ``/dev/XXX`` 4046 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4047 port parameters are set according to the emulated ones. 4048 4049 ``/dev/parportN`` 4050 [Linux only, parallel port only] Use host parallel port N. 4051 Currently SPP and EPP parallel port features can be used. 4052 4053 ``file:filename`` 4054 Write output to filename. No character can be read. 4055 4056 ``stdio`` 4057 [Unix only] standard input/output 4058 4059 ``pipe:filename`` 4060 name pipe filename 4061 4062 ``COMn`` 4063 [Windows only] Use host serial port n 4064 4065 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4066 This implements UDP Net Console. When remote\_host or src\_ip 4067 are not specified they default to ``0.0.0.0``. When not using a 4068 specified src\_port a random port is automatically chosen. 4069 4070 If you just want a simple readonly console you can use 4071 ``netcat`` or ``nc``, by starting QEMU with: 4072 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4073 QEMU writes something to that port it will appear in the 4074 netconsole session. 4075 4076 If you plan to send characters back via netconsole or you want 4077 to stop and start QEMU a lot of times, you should have QEMU use 4078 the same source port each time by using something like ``-serial 4079 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4080 version of netcat which can listen to a TCP port and send and 4081 receive characters via udp. If you have a patched version of 4082 netcat which activates telnet remote echo and single char 4083 transfer, then you can use the following options to set up a 4084 netcat redirector to allow telnet on port 5555 to access the 4085 QEMU port. 4086 4087 ``QEMU Options:`` 4088 -serial udp::4555@:4556 4089 4090 ``netcat options:`` 4091 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4092 4093 ``telnet options:`` 4094 localhost 5555 4095 4096 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4097 The TCP Net Console has two modes of operation. It can send the 4098 serial I/O to a location or wait for a connection from a 4099 location. By default the TCP Net Console is sent to host at the 4100 port. If you use the ``server=on`` option QEMU will wait for a client 4101 socket application to connect to the port before continuing, 4102 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4103 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4104 option only applies if ``server=no`` is set, if the connection goes 4105 down it will attempt to reconnect at the given interval. If host 4106 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4107 time is accepted. You can use ``telnet=on`` to connect to the 4108 corresponding character device. 4109 4110 ``Example to send tcp console to 192.168.0.2 port 4444`` 4111 -serial tcp:192.168.0.2:4444 4112 4113 ``Example to listen and wait on port 4444 for connection`` 4114 -serial tcp::4444,server=on 4115 4116 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4117 -serial tcp:192.168.0.100:4444,server=on,wait=off 4118 4119 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4120 The telnet protocol is used instead of raw tcp sockets. The 4121 options work the same as if you had specified ``-serial tcp``. 4122 The difference is that the port acts like a telnet server or 4123 client using telnet option negotiation. This will also allow you 4124 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4125 supports sending the break sequence. Typically in unix telnet 4126 you do it with Control-] and then type "send break" followed by 4127 pressing the enter key. 4128 4129 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4130 The WebSocket protocol is used instead of raw tcp socket. The 4131 port acts as a WebSocket server. Client mode is not supported. 4132 4133 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4134 A unix domain socket is used instead of a tcp socket. The option 4135 works the same as if you had specified ``-serial tcp`` except 4136 the unix domain socket path is used for connections. 4137 4138 ``mon:dev_string`` 4139 This is a special option to allow the monitor to be multiplexed 4140 onto another serial port. The monitor is accessed with key 4141 sequence of Control-a and then pressing c. dev\_string should be 4142 any one of the serial devices specified above. An example to 4143 multiplex the monitor onto a telnet server listening on port 4144 4444 would be: 4145 4146 ``-serial mon:telnet::4444,server=on,wait=off`` 4147 4148 When the monitor is multiplexed to stdio in this way, Ctrl+C 4149 will not terminate QEMU any more but will be passed to the guest 4150 instead. 4151 4152 ``braille`` 4153 Braille device. This will use BrlAPI to display the braille 4154 output on a real or fake device. 4155 4156 ``msmouse`` 4157 Three button serial mouse. Configure the guest to use Microsoft 4158 protocol. 4159ERST 4160 4161DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4162 "-parallel dev redirect the parallel port to char device 'dev'\n", 4163 QEMU_ARCH_ALL) 4164SRST 4165``-parallel dev`` 4166 Redirect the virtual parallel port to host device dev (same devices 4167 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4168 to use hardware devices connected on the corresponding host parallel 4169 port. 4170 4171 This option can be used several times to simulate up to 3 parallel 4172 ports. 4173 4174 Use ``-parallel none`` to disable all parallel ports. 4175ERST 4176 4177DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4178 "-monitor dev redirect the monitor to char device 'dev'\n", 4179 QEMU_ARCH_ALL) 4180SRST 4181``-monitor dev`` 4182 Redirect the monitor to host device dev (same devices as the serial 4183 port). The default device is ``vc`` in graphical mode and ``stdio`` 4184 in non graphical mode. Use ``-monitor none`` to disable the default 4185 monitor. 4186ERST 4187DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4188 "-qmp dev like -monitor but opens in 'control' mode\n", 4189 QEMU_ARCH_ALL) 4190SRST 4191``-qmp dev`` 4192 Like ``-monitor`` but opens in 'control' mode. For example, to make 4193 QMP available on localhost port 4444:: 4194 4195 -qmp tcp:localhost:4444,server=on,wait=off 4196 4197 Not all options are configurable via this syntax; for maximum 4198 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4199 4200ERST 4201DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4202 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4203 QEMU_ARCH_ALL) 4204SRST 4205``-qmp-pretty dev`` 4206 Like ``-qmp`` but uses pretty JSON formatting. 4207ERST 4208 4209DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4210 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4211SRST 4212``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4213 Set up a monitor connected to the chardev ``name``. 4214 QEMU supports two monitors: the Human Monitor Protocol 4215 (HMP; for human interaction), and the QEMU Monitor Protocol 4216 (QMP; a JSON RPC-style protocol). 4217 The default is HMP; ``mode=control`` selects QMP instead. 4218 ``pretty`` is only valid when ``mode=control``, 4219 turning on JSON pretty printing to ease 4220 human reading and debugging. 4221 4222 For example:: 4223 4224 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4225 -mon chardev=mon1,mode=control,pretty=on 4226 4227 enables the QMP monitor on localhost port 4444 with pretty-printing. 4228ERST 4229 4230DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4231 "-debugcon dev redirect the debug console to char device 'dev'\n", 4232 QEMU_ARCH_ALL) 4233SRST 4234``-debugcon dev`` 4235 Redirect the debug console to host device dev (same devices as the 4236 serial port). The debug console is an I/O port which is typically 4237 port 0xe9; writing to that I/O port sends output to this device. The 4238 default device is ``vc`` in graphical mode and ``stdio`` in non 4239 graphical mode. 4240ERST 4241 4242DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4243 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4244SRST 4245``-pidfile file`` 4246 Store the QEMU process PID in file. It is useful if you launch QEMU 4247 from a script. 4248ERST 4249 4250DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4251 "-singlestep deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL) 4252SRST 4253``-singlestep`` 4254 This is a deprecated synonym for the TCG accelerator property 4255 ``one-insn-per-tb``. 4256ERST 4257 4258DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4259 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4260 QEMU_ARCH_ALL) 4261SRST 4262``--preconfig`` 4263 Pause QEMU for interactive configuration before the machine is 4264 created, which allows querying and configuring properties that will 4265 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4266 exit the preconfig state and move to the next state (i.e. run guest 4267 if -S isn't used or pause the second time if -S is used). This 4268 option is experimental. 4269ERST 4270 4271DEF("S", 0, QEMU_OPTION_S, \ 4272 "-S freeze CPU at startup (use 'c' to start execution)\n", 4273 QEMU_ARCH_ALL) 4274SRST 4275``-S`` 4276 Do not start CPU at startup (you must type 'c' in the monitor). 4277ERST 4278 4279DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4280 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4281 " run qemu with overcommit hints\n" 4282 " mem-lock=on|off controls memory lock support (default: off)\n" 4283 " cpu-pm=on|off controls cpu power management (default: off)\n", 4284 QEMU_ARCH_ALL) 4285SRST 4286``-overcommit mem-lock=on|off`` 4287 \ 4288``-overcommit cpu-pm=on|off`` 4289 Run qemu with hints about host resource overcommit. The default is 4290 to assume that host overcommits all resources. 4291 4292 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4293 (disabled by default). This works when host memory is not 4294 overcommitted and reduces the worst-case latency for guest. 4295 4296 Guest ability to manage power state of host cpus (increasing latency 4297 for other processes on the same host cpu, but decreasing latency for 4298 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4299 works best when host CPU is not overcommitted. When used, host 4300 estimates of CPU cycle and power utilization will be incorrect, not 4301 taking into account guest idle time. 4302ERST 4303 4304DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4305 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4306 " the guest without waiting for gdb to connect; use -S too\n" 4307 " if you want it to not start execution.)\n", 4308 QEMU_ARCH_ALL) 4309SRST 4310``-gdb dev`` 4311 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4312 in the System Emulation Users Guide). Note that this option does not pause QEMU 4313 execution -- if you want QEMU to not start the guest until you 4314 connect with gdb and issue a ``continue`` command, you will need to 4315 also pass the ``-S`` option to QEMU. 4316 4317 The most usual configuration is to listen on a local TCP socket:: 4318 4319 -gdb tcp::3117 4320 4321 but you can specify other backends; UDP, pseudo TTY, or even stdio 4322 are all reasonable use cases. For example, a stdio connection 4323 allows you to start QEMU from within gdb and establish the 4324 connection via a pipe: 4325 4326 .. parsed-literal:: 4327 4328 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4329ERST 4330 4331DEF("s", 0, QEMU_OPTION_s, \ 4332 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4333 QEMU_ARCH_ALL) 4334SRST 4335``-s`` 4336 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4337 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4338ERST 4339 4340DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4341 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4342 QEMU_ARCH_ALL) 4343SRST 4344``-d item1[,...]`` 4345 Enable logging of specified items. Use '-d help' for a list of log 4346 items. 4347ERST 4348 4349DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4350 "-D logfile output log to logfile (default stderr)\n", 4351 QEMU_ARCH_ALL) 4352SRST 4353``-D logfile`` 4354 Output log in logfile instead of to stderr 4355ERST 4356 4357DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4358 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4359 QEMU_ARCH_ALL) 4360SRST 4361``-dfilter range1[,...]`` 4362 Filter debug output to that relevant to a range of target addresses. 4363 The filter spec can be either start+size, start-size or start..end 4364 where start end and size are the addresses and sizes required. For 4365 example: 4366 4367 :: 4368 4369 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4370 4371 Will dump output for any code in the 0x1000 sized block starting at 4372 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4373 another 0x1000 sized block starting at 0xffffffc00005f000. 4374ERST 4375 4376DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4377 "-seed number seed the pseudo-random number generator\n", 4378 QEMU_ARCH_ALL) 4379SRST 4380``-seed number`` 4381 Force the guest to use a deterministic pseudo-random number 4382 generator, seeded with number. This does not affect crypto routines 4383 within the host. 4384ERST 4385 4386DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4387 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4388 QEMU_ARCH_ALL) 4389SRST 4390``-L path`` 4391 Set the directory for the BIOS, VGA BIOS and keymaps. 4392 4393 To list all the data directories, use ``-L help``. 4394ERST 4395 4396DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4397 "-enable-kvm enable KVM full virtualization support\n", 4398 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4399 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4400SRST 4401``-enable-kvm`` 4402 Enable KVM full virtualization support. This option is only 4403 available if KVM support is enabled when compiling. 4404ERST 4405 4406DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4407 "-xen-domid id specify xen guest domain id\n", 4408 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4409DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4410 "-xen-attach attach to existing xen domain\n" 4411 " libxl will use this when starting QEMU\n", 4412 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4413DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4414 "-xen-domid-restrict restrict set of available xen operations\n" 4415 " to specified domain id. (Does not affect\n" 4416 " xenpv machine type).\n", 4417 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4418SRST 4419``-xen-domid id`` 4420 Specify xen guest domain id (XEN only). 4421 4422``-xen-attach`` 4423 Attach to existing xen domain. libxl will use this when starting 4424 QEMU (XEN only). Restrict set of available xen operations to 4425 specified domain id (XEN only). 4426ERST 4427 4428DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4429 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4430SRST 4431``-no-reboot`` 4432 Exit instead of rebooting. 4433ERST 4434 4435DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4436 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4437SRST 4438``-no-shutdown`` 4439 Don't exit QEMU on guest shutdown, but instead only stop the 4440 emulation. This allows for instance switching to monitor to commit 4441 changes to the disk image. 4442ERST 4443 4444DEF("action", HAS_ARG, QEMU_OPTION_action, 4445 "-action reboot=reset|shutdown\n" 4446 " action when guest reboots [default=reset]\n" 4447 "-action shutdown=poweroff|pause\n" 4448 " action when guest shuts down [default=poweroff]\n" 4449 "-action panic=pause|shutdown|exit-failure|none\n" 4450 " action when guest panics [default=shutdown]\n" 4451 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4452 " action when watchdog fires [default=reset]\n", 4453 QEMU_ARCH_ALL) 4454SRST 4455``-action event=action`` 4456 The action parameter serves to modify QEMU's default behavior when 4457 certain guest events occur. It provides a generic method for specifying the 4458 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4459 parameters. 4460 4461 Examples: 4462 4463 ``-action panic=none`` 4464 ``-action reboot=shutdown,shutdown=pause`` 4465 ``-device i6300esb -action watchdog=pause`` 4466 4467ERST 4468 4469DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4470 "-loadvm [tag|id]\n" \ 4471 " start right away with a saved state (loadvm in monitor)\n", 4472 QEMU_ARCH_ALL) 4473SRST 4474``-loadvm file`` 4475 Start right away with a saved state (``loadvm`` in monitor) 4476ERST 4477 4478#ifndef _WIN32 4479DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4480 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4481#endif 4482SRST 4483``-daemonize`` 4484 Daemonize the QEMU process after initialization. QEMU will not 4485 detach from standard IO until it is ready to receive connections on 4486 any of its devices. This option is a useful way for external 4487 programs to launch QEMU without having to cope with initialization 4488 race conditions. 4489ERST 4490 4491DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4492 "-option-rom rom load a file, rom, into the option ROM space\n", 4493 QEMU_ARCH_ALL) 4494SRST 4495``-option-rom file`` 4496 Load the contents of file as an option ROM. This option is useful to 4497 load things like EtherBoot. 4498ERST 4499 4500DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4501 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4502 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4503 QEMU_ARCH_ALL) 4504 4505SRST 4506``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4507 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4508 the current UTC or local time, respectively. ``localtime`` is 4509 required for correct date in MS-DOS or Windows. To start at a 4510 specific point in time, provide datetime in the format 4511 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4512 4513 By default the RTC is driven by the host system time. This allows 4514 using of the RTC as accurate reference clock inside the guest, 4515 specifically if the host time is smoothly following an accurate 4516 external reference clock, e.g. via NTP. If you want to isolate the 4517 guest time from the host, you can set ``clock`` to ``rt`` instead, 4518 which provides a host monotonic clock if host support it. To even 4519 prevent the RTC from progressing during suspension, you can set 4520 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4521 recommended especially in icount mode in order to preserve 4522 determinism; however, note that in icount mode the speed of the 4523 virtual clock is variable and can in general differ from the host 4524 clock. 4525 4526 Enable ``driftfix`` (i386 targets only) if you experience time drift 4527 problems, specifically with Windows' ACPI HAL. This option will try 4528 to figure out how many timer interrupts were not processed by the 4529 Windows guest and will re-inject them. 4530ERST 4531 4532DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4533 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4534 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4535 " instruction, enable aligning the host and virtual clocks\n" \ 4536 " or disable real time cpu sleeping, and optionally enable\n" \ 4537 " record-and-replay mode\n", QEMU_ARCH_ALL) 4538SRST 4539``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4540 Enable virtual instruction counter. The virtual cpu will execute one 4541 instruction every 2^N ns of virtual time. If ``auto`` is specified 4542 then the virtual cpu speed will be automatically adjusted to keep 4543 virtual time within a few seconds of real time. 4544 4545 Note that while this option can give deterministic behavior, it does 4546 not provide cycle accurate emulation. Modern CPUs contain 4547 superscalar out of order cores with complex cache hierarchies. The 4548 number of instructions executed often has little or no correlation 4549 with actual performance. 4550 4551 When the virtual cpu is sleeping, the virtual time will advance at 4552 default speed unless ``sleep=on`` is specified. With 4553 ``sleep=on``, the virtual time will jump to the next timer 4554 deadline instantly whenever the virtual cpu goes to sleep mode and 4555 will not advance if no timer is enabled. This behavior gives 4556 deterministic execution times from the guest point of view. 4557 The default if icount is enabled is ``sleep=off``. 4558 ``sleep=on`` cannot be used together with either ``shift=auto`` 4559 or ``align=on``. 4560 4561 ``align=on`` will activate the delay algorithm which will try to 4562 synchronise the host clock and the virtual clock. The goal is to 4563 have a guest running at the real frequency imposed by the shift 4564 option. Whenever the guest clock is behind the host clock and if 4565 ``align=on`` is specified then we print a message to the user to 4566 inform about the delay. Currently this option does not work when 4567 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4568 shift values for which the guest clock runs ahead of the host clock. 4569 Typically this happens when the shift value is high (how high 4570 depends on the host machine). The default if icount is enabled 4571 is ``align=off``. 4572 4573 When the ``rr`` option is specified deterministic record/replay is 4574 enabled. The ``rrfile=`` option must also be provided to 4575 specify the path to the replay log. In record mode data is written 4576 to this file, and in replay mode it is read back. 4577 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4578 name. In record mode, a new VM snapshot with the given name is created 4579 at the start of execution recording. In replay mode this option 4580 specifies the snapshot name used to load the initial VM state. 4581ERST 4582 4583DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4584 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4585 " action when watchdog fires [default=reset]\n", 4586 QEMU_ARCH_ALL) 4587SRST 4588``-watchdog-action action`` 4589 The action controls what QEMU will do when the watchdog timer 4590 expires. The default is ``reset`` (forcefully reset the guest). 4591 Other possible actions are: ``shutdown`` (attempt to gracefully 4592 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4593 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4594 guest), ``debug`` (print a debug message and continue), or ``none`` 4595 (do nothing). 4596 4597 Note that the ``shutdown`` action requires that the guest responds 4598 to ACPI signals, which it may not be able to do in the sort of 4599 situations where the watchdog would have expired, and thus 4600 ``-watchdog-action shutdown`` is not recommended for production use. 4601 4602 Examples: 4603 4604 ``-device i6300esb -watchdog-action pause`` 4605 4606ERST 4607 4608DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4609 "-echr chr set terminal escape character instead of ctrl-a\n", 4610 QEMU_ARCH_ALL) 4611SRST 4612``-echr numeric_ascii_value`` 4613 Change the escape character used for switching to the monitor when 4614 using monitor and serial sharing. The default is ``0x01`` when using 4615 the ``-nographic`` option. ``0x01`` is equal to pressing 4616 ``Control-a``. You can select a different character from the ascii 4617 control keys where 1 through 26 map to Control-a through Control-z. 4618 For instance you could use the either of the following to change the 4619 escape character to Control-t. 4620 4621 ``-echr 0x14``; \ ``-echr 20`` 4622 4623ERST 4624 4625DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4626 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4627 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4628 "-incoming unix:socketpath\n" \ 4629 " prepare for incoming migration, listen on\n" \ 4630 " specified protocol and socket address\n" \ 4631 "-incoming fd:fd\n" \ 4632 "-incoming exec:cmdline\n" \ 4633 " accept incoming migration on given file descriptor\n" \ 4634 " or from given external command\n" \ 4635 "-incoming defer\n" \ 4636 " wait for the URI to be specified via migrate_incoming\n", 4637 QEMU_ARCH_ALL) 4638SRST 4639``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4640 \ 4641``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4642 Prepare for incoming migration, listen on a given tcp port. 4643 4644``-incoming unix:socketpath`` 4645 Prepare for incoming migration, listen on a given unix socket. 4646 4647``-incoming fd:fd`` 4648 Accept incoming migration from a given filedescriptor. 4649 4650``-incoming exec:cmdline`` 4651 Accept incoming migration as an output from specified external 4652 command. 4653 4654``-incoming defer`` 4655 Wait for the URI to be specified via migrate\_incoming. The monitor 4656 can be used to change settings (such as migration parameters) prior 4657 to issuing the migrate\_incoming to allow the migration to begin. 4658ERST 4659 4660DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4661 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4662SRST 4663``-only-migratable`` 4664 Only allow migratable devices. Devices will not be allowed to enter 4665 an unmigratable state. 4666ERST 4667 4668DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4669 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4670SRST 4671``-nodefaults`` 4672 Don't create default devices. Normally, QEMU sets the default 4673 devices like serial port, parallel port, virtual console, monitor 4674 device, VGA adapter, floppy and CD-ROM drive and others. The 4675 ``-nodefaults`` option will disable all those default devices. 4676ERST 4677 4678#ifndef _WIN32 4679DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4680 "-chroot dir chroot to dir just before starting the VM (deprecated)\n", 4681 QEMU_ARCH_ALL) 4682#endif 4683SRST 4684``-chroot dir`` 4685 Deprecated, use '-run-with chroot=...' instead. 4686 Immediately before starting guest execution, chroot to the specified 4687 directory. Especially useful in combination with -runas. 4688ERST 4689 4690#ifndef _WIN32 4691DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4692 "-runas user change to user id user just before starting the VM\n" \ 4693 " user can be numeric uid:gid instead\n", 4694 QEMU_ARCH_ALL) 4695#endif 4696SRST 4697``-runas user`` 4698 Immediately before starting guest execution, drop root privileges, 4699 switching to the specified user. 4700ERST 4701 4702DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4703 "-prom-env variable=value\n" 4704 " set OpenBIOS nvram variables\n", 4705 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4706SRST 4707``-prom-env variable=value`` 4708 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4709 4710 :: 4711 4712 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4713 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4714 4715 :: 4716 4717 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4718 -prom-env 'boot-device=hd:2,\yaboot' \ 4719 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4720ERST 4721DEF("semihosting", 0, QEMU_OPTION_semihosting, 4722 "-semihosting semihosting mode\n", 4723 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4724 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4725SRST 4726``-semihosting`` 4727 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4728 4729 .. warning:: 4730 Note that this allows guest direct access to the host filesystem, so 4731 should only be used with a trusted guest OS. 4732 4733 See the -semihosting-config option documentation for further 4734 information about the facilities this enables. 4735ERST 4736DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4737 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4738 " semihosting configuration\n", 4739QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4740QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4741SRST 4742``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4743 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4744 only). 4745 4746 .. warning:: 4747 Note that this allows guest direct access to the host filesystem, so 4748 should only be used with a trusted guest OS. 4749 4750 ``target=native|gdb|auto`` 4751 Defines where the semihosting calls will be addressed, to QEMU 4752 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4753 means ``gdb`` during debug sessions and ``native`` otherwise. 4754 4755 ``chardev=str1`` 4756 Send the output to a chardev backend output for native or auto 4757 output when not in gdb 4758 4759 ``userspace=on|off`` 4760 Allows code running in guest userspace to access the semihosting 4761 interface. The default is that only privileged guest code can 4762 make semihosting calls. Note that setting ``userspace=on`` should 4763 only be used if all guest code is trusted (for example, in 4764 bare-metal test case code). 4765 4766 ``arg=str1,arg=str2,...`` 4767 Allows the user to pass input arguments, and can be used 4768 multiple times to build up a list. The old-style 4769 ``-kernel``/``-append`` method of passing a command line is 4770 still supported for backward compatibility. If both the 4771 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4772 specified, the former is passed to semihosting as it always 4773 takes precedence. 4774ERST 4775DEF("old-param", 0, QEMU_OPTION_old_param, 4776 "-old-param old param mode\n", QEMU_ARCH_ARM) 4777SRST 4778``-old-param`` 4779 Old param mode (ARM only). 4780ERST 4781 4782DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4783 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4784 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4785 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4786 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4787 " by the kernel, but typically no longer used by modern\n" \ 4788 " C library implementations.\n" \ 4789 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4790 " to elevate privileges using set*uid|gid system calls.\n" \ 4791 " The value 'children' will deny set*uid|gid system calls for\n" \ 4792 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4793 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4794 " blocking *fork and execve\n" \ 4795 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4796 QEMU_ARCH_ALL) 4797SRST 4798``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4799 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4800 filtering and 'off' will disable it. The default is 'off'. 4801 4802 ``obsolete=string`` 4803 Enable Obsolete system calls 4804 4805 ``elevateprivileges=string`` 4806 Disable set\*uid\|gid system calls 4807 4808 ``spawn=string`` 4809 Disable \*fork and execve 4810 4811 ``resourcecontrol=string`` 4812 Disable process affinity and schedular priority 4813ERST 4814 4815DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4816 "-readconfig <file>\n" 4817 " read config file\n", QEMU_ARCH_ALL) 4818SRST 4819``-readconfig file`` 4820 Read device configuration from file. This approach is useful when 4821 you want to spawn QEMU process with many command line options but 4822 you don't want to exceed the command line character limit. 4823ERST 4824 4825DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4826 "-no-user-config\n" 4827 " do not load default user-provided config files at startup\n", 4828 QEMU_ARCH_ALL) 4829SRST 4830``-no-user-config`` 4831 The ``-no-user-config`` option makes QEMU not load any of the 4832 user-provided config files on sysconfdir. 4833ERST 4834 4835DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4836 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4837 " specify tracing options\n", 4838 QEMU_ARCH_ALL) 4839SRST 4840``-trace [[enable=]pattern][,events=file][,file=file]`` 4841 .. include:: ../qemu-option-trace.rst.inc 4842 4843ERST 4844DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4845 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4846 " load a plugin\n", 4847 QEMU_ARCH_ALL) 4848SRST 4849``-plugin file=file[,argname=argvalue]`` 4850 Load a plugin. 4851 4852 ``file=file`` 4853 Load the given plugin from a shared library file. 4854 4855 ``argname=argvalue`` 4856 Argument passed to the plugin. (Can be given multiple times.) 4857ERST 4858 4859HXCOMM Internal use 4860DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4861DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4862 4863#ifdef __linux__ 4864DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4865 "-async-teardown enable asynchronous teardown\n", 4866 QEMU_ARCH_ALL) 4867SRST 4868``-async-teardown`` 4869 This option is deprecated and should no longer be used. The new option 4870 ``-run-with async-teardown=on`` is a replacement. 4871ERST 4872#endif 4873#ifdef CONFIG_POSIX 4874DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4875 "-run-with [async-teardown=on|off][,chroot=dir]\n" 4876 " Set miscellaneous QEMU process lifecycle options:\n" 4877 " async-teardown=on enables asynchronous teardown (Linux only)\n" 4878 " chroot=dir chroot to dir just before starting the VM\n", 4879 QEMU_ARCH_ALL) 4880SRST 4881``-run-with [async-teardown=on|off][,chroot=dir]`` 4882 Set QEMU process lifecycle options. 4883 4884 ``async-teardown=on`` enables asynchronous teardown. A new process called 4885 "cleanup/<QEMU_PID>" will be created at startup sharing the address 4886 space with the main QEMU process, using clone. It will wait for the 4887 main QEMU process to terminate completely, and then exit. This allows 4888 QEMU to terminate very quickly even if the guest was huge, leaving the 4889 teardown of the address space to the cleanup process. Since the cleanup 4890 process shares the same cgroups as the main QEMU process, accounting is 4891 performed correctly. This only works if the cleanup process is not 4892 forcefully killed with SIGKILL before the main QEMU process has 4893 terminated completely. 4894 4895 ``chroot=dir`` can be used for doing a chroot to the specified directory 4896 immediately before starting the guest execution. This is especially useful 4897 in combination with -runas. 4898ERST 4899#endif 4900 4901DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4902 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4903 " control error message format\n" 4904 " timestamp=on enables timestamps (default: off)\n" 4905 " guest-name=on enables guest name prefix but only if\n" 4906 " -name guest option is set (default: off)\n", 4907 QEMU_ARCH_ALL) 4908SRST 4909``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4910 Control error message format. 4911 4912 ``timestamp=on|off`` 4913 Prefix messages with a timestamp. Default is off. 4914 4915 ``guest-name=on|off`` 4916 Prefix messages with guest name but only if -name guest option is set 4917 otherwise the option is ignored. Default is off. 4918ERST 4919 4920DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4921 "-dump-vmstate <file>\n" 4922 " Output vmstate information in JSON format to file.\n" 4923 " Use the scripts/vmstate-static-checker.py file to\n" 4924 " check for possible regressions in migration code\n" 4925 " by comparing two such vmstate dumps.\n", 4926 QEMU_ARCH_ALL) 4927SRST 4928``-dump-vmstate file`` 4929 Dump json-encoded vmstate information for current machine type to 4930 file in file 4931ERST 4932 4933DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4934 "-enable-sync-profile\n" 4935 " enable synchronization profiling\n", 4936 QEMU_ARCH_ALL) 4937SRST 4938``-enable-sync-profile`` 4939 Enable synchronization profiling. 4940ERST 4941 4942#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 4943DEF("perfmap", 0, QEMU_OPTION_perfmap, 4944 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 4945 QEMU_ARCH_ALL) 4946SRST 4947``-perfmap`` 4948 Generate a map file for Linux perf tools that will allow basic profiling 4949 information to be broken down into basic blocks. 4950ERST 4951 4952DEF("jitdump", 0, QEMU_OPTION_jitdump, 4953 "-jitdump generate a jit-${pid}.dump file for perf\n", 4954 QEMU_ARCH_ALL) 4955SRST 4956``-jitdump`` 4957 Generate a dump file for Linux perf tools that maps basic blocks to symbol 4958 names, line numbers and JITted code. 4959ERST 4960#endif 4961 4962DEFHEADING() 4963 4964DEFHEADING(Generic object creation:) 4965 4966DEF("object", HAS_ARG, QEMU_OPTION_object, 4967 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4968 " create a new object of type TYPENAME setting properties\n" 4969 " in the order they are specified. Note that the 'id'\n" 4970 " property must be set. These objects are placed in the\n" 4971 " '/objects' path.\n", 4972 QEMU_ARCH_ALL) 4973SRST 4974``-object typename[,prop1=value1,...]`` 4975 Create a new object of type typename setting properties in the order 4976 they are specified. Note that the 'id' property must be set. These 4977 objects are placed in the '/objects' path. 4978 4979 ``-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`` 4980 Creates a memory file backend object, which can be used to back 4981 the guest RAM with huge pages. 4982 4983 The ``id`` parameter is a unique ID that will be used to 4984 reference this memory region in other parameters, e.g. ``-numa``, 4985 ``-device nvdimm``, etc. 4986 4987 The ``size`` option provides the size of the memory region, and 4988 accepts common suffixes, e.g. ``500M``. 4989 4990 The ``mem-path`` provides the path to either a shared memory or 4991 huge page filesystem mount. 4992 4993 The ``share`` boolean option determines whether the memory 4994 region is marked as private to QEMU, or shared. The latter 4995 allows a co-operating external process to access the QEMU memory 4996 region. 4997 4998 The ``share`` is also required for pvrdma devices due to 4999 limitations in the RDMA API provided by Linux. 5000 5001 Setting share=on might affect the ability to configure NUMA 5002 bindings for the memory backend under some circumstances, see 5003 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5004 source tree for additional details. 5005 5006 Setting the ``discard-data`` boolean option to on indicates that 5007 file contents can be destroyed when QEMU exits, to avoid 5008 unnecessarily flushing data to the backing file. Note that 5009 ``discard-data`` is only an optimization, and QEMU might not 5010 discard file contents if it aborts unexpectedly or is terminated 5011 using SIGKILL. 5012 5013 The ``merge`` boolean option enables memory merge, also known as 5014 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5015 the pages for memory deduplication. 5016 5017 Setting the ``dump`` boolean option to off excludes the memory 5018 from core dumps. This feature is also known as MADV\_DONTDUMP. 5019 5020 The ``prealloc`` boolean option enables memory preallocation. 5021 5022 The ``host-nodes`` option binds the memory range to a list of 5023 NUMA host nodes. 5024 5025 The ``policy`` option sets the NUMA policy to one of the 5026 following values: 5027 5028 ``default`` 5029 default host policy 5030 5031 ``preferred`` 5032 prefer the given host node list for allocation 5033 5034 ``bind`` 5035 restrict memory allocation to the given host node list 5036 5037 ``interleave`` 5038 interleave memory allocations across the given host node 5039 list 5040 5041 The ``align`` option specifies the base address alignment when 5042 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5043 ``2M``. Some backend store specified by ``mem-path`` requires an 5044 alignment different than the default one used by QEMU, eg the 5045 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5046 such cases, users can specify the required alignment via this 5047 option. 5048 5049 The ``offset`` option specifies the offset into the target file 5050 that the region starts at. You can use this parameter to back 5051 multiple regions with a single file. 5052 5053 The ``pmem`` option specifies whether the backing file specified 5054 by ``mem-path`` is in host persistent memory that can be 5055 accessed using the SNIA NVM programming model (e.g. Intel 5056 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5057 operations to guarantee the persistence of its own writes to 5058 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5059 migration). Also, we will map the backend-file with MAP\_SYNC 5060 flag, which ensures the file metadata is in sync for 5061 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5062 requires support from both the host kernel (since Linux kernel 5063 4.15) and the filesystem of ``mem-path`` mounted with DAX 5064 option. 5065 5066 The ``readonly`` option specifies whether the backing file is opened 5067 read-only or read-write (default). 5068 5069 ``-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`` 5070 Creates a memory backend object, which can be used to back the 5071 guest RAM. Memory backend objects offer more control than the 5072 ``-m`` option that is traditionally used to define guest RAM. 5073 Please refer to ``memory-backend-file`` for a description of the 5074 options. 5075 5076 ``-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`` 5077 Creates an anonymous memory file backend object, which allows 5078 QEMU to share the memory with an external process (e.g. when 5079 using vhost-user). The memory is allocated with memfd and 5080 optional sealing. (Linux only) 5081 5082 The ``seal`` option creates a sealed-file, that will block 5083 further resizing the memory ('on' by default). 5084 5085 The ``hugetlb`` option specify the file to be created resides in 5086 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5087 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5088 the hugetlb page size on systems that support multiple hugetlb 5089 page sizes (it must be a power of 2 value supported by the 5090 system). 5091 5092 In some versions of Linux, the ``hugetlb`` option is 5093 incompatible with the ``seal`` option (requires at least Linux 5094 4.16). 5095 5096 Please refer to ``memory-backend-file`` for a description of the 5097 other options. 5098 5099 The ``share`` boolean option is on by default with memfd. 5100 5101 ``-object rng-builtin,id=id`` 5102 Creates a random number generator backend which obtains entropy 5103 from QEMU builtin functions. The ``id`` parameter is a unique ID 5104 that will be used to reference this entropy backend from the 5105 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5106 uses this RNG backend. 5107 5108 ``-object rng-random,id=id,filename=/dev/random`` 5109 Creates a random number generator backend which obtains entropy 5110 from a device on the host. The ``id`` parameter is a unique ID 5111 that will be used to reference this entropy backend from the 5112 ``virtio-rng`` device. The ``filename`` parameter specifies 5113 which file to obtain entropy from and if omitted defaults to 5114 ``/dev/urandom``. 5115 5116 ``-object rng-egd,id=id,chardev=chardevid`` 5117 Creates a random number generator backend which obtains entropy 5118 from an external daemon running on the host. The ``id`` 5119 parameter is a unique ID that will be used to reference this 5120 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5121 parameter is the unique ID of a character device backend that 5122 provides the connection to the RNG daemon. 5123 5124 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5125 Creates a TLS anonymous credentials object, which can be used to 5126 provide TLS support on network backends. The ``id`` parameter is 5127 a unique ID which network backends will use to access the 5128 credentials. The ``endpoint`` is either ``server`` or ``client`` 5129 depending on whether the QEMU network backend that uses the 5130 credentials will be acting as a client or as a server. If 5131 ``verify-peer`` is enabled (the default) then once the handshake 5132 is completed, the peer credentials will be verified, though this 5133 is a no-op for anonymous credentials. 5134 5135 The dir parameter tells QEMU where to find the credential files. 5136 For server endpoints, this directory may contain a file 5137 dh-params.pem providing diffie-hellman parameters to use for the 5138 TLS server. If the file is missing, QEMU will generate a set of 5139 DH parameters at startup. This is a computationally expensive 5140 operation that consumes random pool entropy, so it is 5141 recommended that a persistent set of parameters be generated 5142 upfront and saved. 5143 5144 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5145 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5146 can be used to provide TLS support on network backends. The 5147 ``id`` parameter is a unique ID which network backends will use 5148 to access the credentials. The ``endpoint`` is either ``server`` 5149 or ``client`` depending on whether the QEMU network backend that 5150 uses the credentials will be acting as a client or as a server. 5151 For clients only, ``username`` is the username which will be 5152 sent to the server. If omitted it defaults to "qemu". 5153 5154 The dir parameter tells QEMU where to find the keys file. It is 5155 called "dir/keys.psk" and contains "username:key" pairs. This 5156 file can most easily be created using the GnuTLS ``psktool`` 5157 program. 5158 5159 For server endpoints, dir may also contain a file dh-params.pem 5160 providing diffie-hellman parameters to use for the TLS server. 5161 If the file is missing, QEMU will generate a set of DH 5162 parameters at startup. This is a computationally expensive 5163 operation that consumes random pool entropy, so it is 5164 recommended that a persistent set of parameters be generated up 5165 front and saved. 5166 5167 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5168 Creates a TLS anonymous credentials object, which can be used to 5169 provide TLS support on network backends. The ``id`` parameter is 5170 a unique ID which network backends will use to access the 5171 credentials. The ``endpoint`` is either ``server`` or ``client`` 5172 depending on whether the QEMU network backend that uses the 5173 credentials will be acting as a client or as a server. If 5174 ``verify-peer`` is enabled (the default) then once the handshake 5175 is completed, the peer credentials will be verified. With x509 5176 certificates, this implies that the clients must be provided 5177 with valid client certificates too. 5178 5179 The dir parameter tells QEMU where to find the credential files. 5180 For server endpoints, this directory may contain a file 5181 dh-params.pem providing diffie-hellman parameters to use for the 5182 TLS server. If the file is missing, QEMU will generate a set of 5183 DH parameters at startup. This is a computationally expensive 5184 operation that consumes random pool entropy, so it is 5185 recommended that a persistent set of parameters be generated 5186 upfront and saved. 5187 5188 For x509 certificate credentials the directory will contain 5189 further files providing the x509 certificates. The certificates 5190 must be stored in PEM format, in filenames ca-cert.pem, 5191 ca-crl.pem (optional), server-cert.pem (only servers), 5192 server-key.pem (only servers), client-cert.pem (only clients), 5193 and client-key.pem (only clients). 5194 5195 For the server-key.pem and client-key.pem files which contain 5196 sensitive private keys, it is possible to use an encrypted 5197 version by providing the passwordid parameter. This provides the 5198 ID of a previously created ``secret`` object containing the 5199 password for decryption. 5200 5201 The priority parameter allows to override the global default 5202 priority used by gnutls. This can be useful if the system 5203 administrator needs to use a weaker set of crypto priorities for 5204 QEMU without potentially forcing the weakness onto all 5205 applications. Or conversely if one wants wants a stronger 5206 default for QEMU than for all other applications, they can do 5207 this through this parameter. Its format is a gnutls priority 5208 string as described at 5209 https://gnutls.org/manual/html_node/Priority-Strings.html. 5210 5211 ``-object tls-cipher-suites,id=id,priority=priority`` 5212 Creates a TLS cipher suites object, which can be used to control 5213 the TLS cipher/protocol algorithms that applications are permitted 5214 to use. 5215 5216 The ``id`` parameter is a unique ID which frontends will use to 5217 access the ordered list of permitted TLS cipher suites from the 5218 host. 5219 5220 The ``priority`` parameter allows to override the global default 5221 priority used by gnutls. This can be useful if the system 5222 administrator needs to use a weaker set of crypto priorities for 5223 QEMU without potentially forcing the weakness onto all 5224 applications. Or conversely if one wants wants a stronger 5225 default for QEMU than for all other applications, they can do 5226 this through this parameter. Its format is a gnutls priority 5227 string as described at 5228 https://gnutls.org/manual/html_node/Priority-Strings.html. 5229 5230 An example of use of this object is to control UEFI HTTPS Boot. 5231 The tls-cipher-suites object exposes the ordered list of permitted 5232 TLS cipher suites from the host side to the guest firmware, via 5233 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5234 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5235 guest-side TLS. 5236 5237 In the following example, the priority at which the host-side policy 5238 is retrieved is given by the ``priority`` property. 5239 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5240 refer to /etc/crypto-policies/back-ends/gnutls.config. 5241 5242 .. parsed-literal:: 5243 5244 # |qemu_system| \\ 5245 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5246 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5247 5248 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5249 Interval t can't be 0, this filter batches the packet delivery: 5250 all packets arriving in a given interval on netdev netdevid are 5251 delayed until the end of the interval. Interval is in 5252 microseconds. ``status`` is optional that indicate whether the 5253 netfilter is on (enabled) or off (disabled), the default status 5254 for netfilter will be 'on'. 5255 5256 queue all\|rx\|tx is an option that can be applied to any 5257 netfilter. 5258 5259 ``all``: the filter is attached both to the receive and the 5260 transmit queue of the netdev (default). 5261 5262 ``rx``: the filter is attached to the receive queue of the 5263 netdev, where it will receive packets sent to the netdev. 5264 5265 ``tx``: the filter is attached to the transmit queue of the 5266 netdev, where it will receive packets sent by the netdev. 5267 5268 position head\|tail\|id=<id> is an option to specify where the 5269 filter should be inserted in the filter list. It can be applied 5270 to any netfilter. 5271 5272 ``head``: the filter is inserted at the head of the filter list, 5273 before any existing filters. 5274 5275 ``tail``: the filter is inserted at the tail of the filter list, 5276 behind any existing filters (default). 5277 5278 ``id=<id>``: the filter is inserted before or behind the filter 5279 specified by <id>, see the insert option below. 5280 5281 insert behind\|before is an option to specify where to insert 5282 the new filter relative to the one specified with 5283 position=id=<id>. It can be applied to any netfilter. 5284 5285 ``before``: insert before the specified filter. 5286 5287 ``behind``: insert behind the specified filter (default). 5288 5289 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5290 filter-mirror on netdev netdevid,mirror net packet to 5291 chardevchardevid, if it has the vnet\_hdr\_support flag, 5292 filter-mirror will mirror packet with vnet\_hdr\_len. 5293 5294 ``-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]`` 5295 filter-redirector on netdev netdevid,redirect filter's net 5296 packet to chardev chardevid,and redirect indev's packet to 5297 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5298 will redirect packet with vnet\_hdr\_len. Create a 5299 filter-redirector we need to differ outdev id from indev id, id 5300 can not be the same. we can just use indev or outdev, but at 5301 least one of indev or outdev need to be specified. 5302 5303 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5304 Filter-rewriter is a part of COLO project.It will rewrite tcp 5305 packet to secondary from primary to keep secondary tcp 5306 connection,and rewrite tcp packet to primary from secondary make 5307 tcp packet can be handled by client.if it has the 5308 vnet\_hdr\_support flag, we can parse packet with vnet header. 5309 5310 usage: colo secondary: -object 5311 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5312 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5313 filter-rewriter,id=rew0,netdev=hn0,queue=all 5314 5315 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5316 Dump the network traffic on netdev dev to the file specified by 5317 filename. At most len bytes (64k by default) per packet are 5318 stored. The file format is libpcap, so it can be analyzed with 5319 tools such as tcpdump or Wireshark. 5320 5321 ``-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}]`` 5322 Colo-compare gets packet from primary\_in chardevid and 5323 secondary\_in, then compare whether the payload of primary packet 5324 and secondary packet are the same. If same, it will output 5325 primary packet to out\_dev, else it will notify COLO-framework to do 5326 checkpoint and send primary packet to out\_dev. In order to 5327 improve efficiency, we need to put the task of comparison in 5328 another iothread. If it has the vnet\_hdr\_support flag, 5329 colo compare will send/recv packet with vnet\_hdr\_len. 5330 The compare\_timeout=@var{ms} determines the maximum time of the 5331 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5332 is to set the period of scanning expired primary node network packets. 5333 The max\_queue\_size=@var{size} is to set the max compare queue 5334 size depend on user environment. 5335 If user want to use Xen COLO, need to add the notify\_dev to 5336 notify Xen colo-frame to do checkpoint. 5337 5338 COLO-compare must be used with the help of filter-mirror, 5339 filter-redirector and filter-rewriter. 5340 5341 :: 5342 5343 KVM COLO 5344 5345 primary: 5346 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5347 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5348 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5349 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5350 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5351 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5352 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5353 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5354 -object iothread,id=iothread1 5355 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5356 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5357 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5358 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5359 5360 secondary: 5361 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5362 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5363 -chardev socket,id=red0,host=3.3.3.3,port=9003 5364 -chardev socket,id=red1,host=3.3.3.3,port=9004 5365 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5366 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5367 5368 5369 Xen COLO 5370 5371 primary: 5372 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5373 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5374 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5375 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5376 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5377 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5378 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5379 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5380 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5381 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5382 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5383 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5384 -object iothread,id=iothread1 5385 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5386 5387 secondary: 5388 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5389 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5390 -chardev socket,id=red0,host=3.3.3.3,port=9003 5391 -chardev socket,id=red1,host=3.3.3.3,port=9004 5392 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5393 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5394 5395 If you want to know the detail of above command line, you can 5396 read the colo-compare git log. 5397 5398 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5399 Creates a cryptodev backend which executes crypto operations from 5400 the QEMU cipher APIs. The id parameter is a unique ID that will 5401 be used to reference this cryptodev backend from the 5402 ``virtio-crypto`` device. The queues parameter is optional, 5403 which specify the queue number of cryptodev backend, the default 5404 of queues is 1. 5405 5406 .. parsed-literal:: 5407 5408 # |qemu_system| \\ 5409 [...] \\ 5410 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5411 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5412 [...] 5413 5414 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5415 Creates a vhost-user cryptodev backend, backed by a chardev 5416 chardevid. The id parameter is a unique ID that will be used to 5417 reference this cryptodev backend from the ``virtio-crypto`` 5418 device. The chardev should be a unix domain socket backed one. 5419 The vhost-user uses a specifically defined protocol to pass 5420 vhost ioctl replacement messages to an application on the other 5421 end of the socket. The queues parameter is optional, which 5422 specify the queue number of cryptodev backend for multiqueue 5423 vhost-user, the default of queues is 1. 5424 5425 .. parsed-literal:: 5426 5427 # |qemu_system| \\ 5428 [...] \\ 5429 -chardev socket,id=chardev0,path=/path/to/socket \\ 5430 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5431 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5432 [...] 5433 5434 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5435 \ 5436 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5437 Defines a secret to store a password, encryption key, or some 5438 other sensitive data. The sensitive data can either be passed 5439 directly via the data parameter, or indirectly via the file 5440 parameter. Using the data parameter is insecure unless the 5441 sensitive data is encrypted. 5442 5443 The sensitive data can be provided in raw format (the default), 5444 or base64. When encoded as JSON, the raw format only supports 5445 valid UTF-8 characters, so base64 is recommended for sending 5446 binary data. QEMU will convert from which ever format is 5447 provided to the format it needs internally. eg, an RBD password 5448 can be provided in raw format, even though it will be base64 5449 encoded when passed onto the RBD sever. 5450 5451 For added protection, it is possible to encrypt the data 5452 associated with a secret using the AES-256-CBC cipher. Use of 5453 encryption is indicated by providing the keyid and iv 5454 parameters. The keyid parameter provides the ID of a previously 5455 defined secret that contains the AES-256 decryption key. This 5456 key should be 32-bytes long and be base64 encoded. The iv 5457 parameter provides the random initialization vector used for 5458 encryption of this particular secret and should be a base64 5459 encrypted string of the 16-byte IV. 5460 5461 The simplest (insecure) usage is to provide the secret inline 5462 5463 .. parsed-literal:: 5464 5465 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5466 5467 The simplest secure usage is to provide the secret via a file 5468 5469 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5470 secret,id=sec0,file=mypasswd.txt,format=raw 5471 5472 For greater security, AES-256-CBC should be used. To illustrate 5473 usage, consider the openssl command line tool which can encrypt 5474 the data. Note that when encrypting, the plaintext must be 5475 padded to the cipher block size (32 bytes) using the standard 5476 PKCS#5/6 compatible padding algorithm. 5477 5478 First a master key needs to be created in base64 encoding: 5479 5480 :: 5481 5482 # openssl rand -base64 32 > key.b64 5483 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5484 5485 Each secret to be encrypted needs to have a random 5486 initialization vector generated. These do not need to be kept 5487 secret 5488 5489 :: 5490 5491 # openssl rand -base64 16 > iv.b64 5492 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5493 5494 The secret to be defined can now be encrypted, in this case 5495 we're telling openssl to base64 encode the result, but it could 5496 be left as raw bytes if desired. 5497 5498 :: 5499 5500 # SECRET=$(printf "letmein" | 5501 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5502 5503 When launching QEMU, create a master secret pointing to 5504 ``key.b64`` and specify that to be used to decrypt the user 5505 password. Pass the contents of ``iv.b64`` to the second secret 5506 5507 .. parsed-literal:: 5508 5509 # |qemu_system| \\ 5510 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5511 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5512 data=$SECRET,iv=$(<iv.b64) 5513 5514 ``-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]`` 5515 Create a Secure Encrypted Virtualization (SEV) guest object, 5516 which can be used to provide the guest memory encryption support 5517 on AMD processors. 5518 5519 When memory encryption is enabled, one of the physical address 5520 bit (aka the C-bit) is utilized to mark if a memory page is 5521 protected. The ``cbitpos`` is used to provide the C-bit 5522 position. The C-bit position is Host family dependent hence user 5523 must provide this value. On EPYC, the value should be 47. 5524 5525 When memory encryption is enabled, we loose certain bits in 5526 physical address space. The ``reduced-phys-bits`` is used to 5527 provide the number of bits we loose in physical address space. 5528 Similar to C-bit, the value is Host family dependent. On EPYC, 5529 a guest will lose a maximum of 1 bit, so the value should be 1. 5530 5531 The ``sev-device`` provides the device file to use for 5532 communicating with the SEV firmware running inside AMD Secure 5533 Processor. The default device is '/dev/sev'. If hardware 5534 supports memory encryption then /dev/sev devices are created by 5535 CCP driver. 5536 5537 The ``policy`` provides the guest policy to be enforced by the 5538 SEV firmware and restrict what configuration and operational 5539 commands can be performed on this guest by the hypervisor. The 5540 policy should be provided by the guest owner and is bound to the 5541 guest and cannot be changed throughout the lifetime of the 5542 guest. The default is 0. 5543 5544 If guest ``policy`` allows sharing the key with another SEV 5545 guest then ``handle`` can be use to provide handle of the guest 5546 from which to share the key. 5547 5548 The ``dh-cert-file`` and ``session-file`` provides the guest 5549 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5550 and session parameters are used for establishing a cryptographic 5551 session with the guest owner to negotiate keys used for 5552 attestation. The file must be encoded in base64. 5553 5554 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5555 cmdline to a designated guest firmware page for measured Linux 5556 boot with -kernel. The default is off. (Since 6.2) 5557 5558 e.g to launch a SEV guest 5559 5560 .. parsed-literal:: 5561 5562 # |qemu_system_x86| \\ 5563 ...... \\ 5564 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5565 -machine ...,memory-encryption=sev0 \\ 5566 ..... 5567 5568 ``-object authz-simple,id=id,identity=string`` 5569 Create an authorization object that will control access to 5570 network services. 5571 5572 The ``identity`` parameter is identifies the user and its format 5573 depends on the network service that authorization object is 5574 associated with. For authorizing based on TLS x509 certificates, 5575 the identity must be the x509 distinguished name. Note that care 5576 must be taken to escape any commas in the distinguished name. 5577 5578 An example authorization object to validate a x509 distinguished 5579 name would look like: 5580 5581 .. parsed-literal:: 5582 5583 # |qemu_system| \\ 5584 ... \\ 5585 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5586 ... 5587 5588 Note the use of quotes due to the x509 distinguished name 5589 containing whitespace, and escaping of ','. 5590 5591 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5592 Create an authorization object that will control access to 5593 network services. 5594 5595 The ``filename`` parameter is the fully qualified path to a file 5596 containing the access control list rules in JSON format. 5597 5598 An example set of rules that match against SASL usernames might 5599 look like: 5600 5601 :: 5602 5603 { 5604 "rules": [ 5605 { "match": "fred", "policy": "allow", "format": "exact" }, 5606 { "match": "bob", "policy": "allow", "format": "exact" }, 5607 { "match": "danb", "policy": "deny", "format": "glob" }, 5608 { "match": "dan*", "policy": "allow", "format": "exact" }, 5609 ], 5610 "policy": "deny" 5611 } 5612 5613 When checking access the object will iterate over all the rules 5614 and the first rule to match will have its ``policy`` value 5615 returned as the result. If no rules match, then the default 5616 ``policy`` value is returned. 5617 5618 The rules can either be an exact string match, or they can use 5619 the simple UNIX glob pattern matching to allow wildcards to be 5620 used. 5621 5622 If ``refresh`` is set to true the file will be monitored and 5623 automatically reloaded whenever its content changes. 5624 5625 As with the ``authz-simple`` object, the format of the identity 5626 strings being matched depends on the network service, but is 5627 usually a TLS x509 distinguished name, or a SASL username. 5628 5629 An example authorization object to validate a SASL username 5630 would look like: 5631 5632 .. parsed-literal:: 5633 5634 # |qemu_system| \\ 5635 ... \\ 5636 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5637 ... 5638 5639 ``-object authz-pam,id=id,service=string`` 5640 Create an authorization object that will control access to 5641 network services. 5642 5643 The ``service`` parameter provides the name of a PAM service to 5644 use for authorization. It requires that a file 5645 ``/etc/pam.d/service`` exist to provide the configuration for 5646 the ``account`` subsystem. 5647 5648 An example authorization object to validate a TLS x509 5649 distinguished name would look like: 5650 5651 .. parsed-literal:: 5652 5653 # |qemu_system| \\ 5654 ... \\ 5655 -object authz-pam,id=auth0,service=qemu-vnc \\ 5656 ... 5657 5658 There would then be a corresponding config file for PAM at 5659 ``/etc/pam.d/qemu-vnc`` that contains: 5660 5661 :: 5662 5663 account requisite pam_listfile.so item=user sense=allow \ 5664 file=/etc/qemu/vnc.allow 5665 5666 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5667 of x509 distinguished names that are permitted access 5668 5669 :: 5670 5671 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5672 5673 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5674 Creates a dedicated event loop thread that devices can be 5675 assigned to. This is known as an IOThread. By default device 5676 emulation happens in vCPU threads or the main event loop thread. 5677 This can become a scalability bottleneck. IOThreads allow device 5678 emulation and I/O to run on other host CPUs. 5679 5680 The ``id`` parameter is a unique ID that will be used to 5681 reference this IOThread from ``-device ...,iothread=id``. 5682 Multiple devices can be assigned to an IOThread. Note that not 5683 all devices support an ``iothread`` parameter. 5684 5685 The ``query-iothreads`` QMP command lists IOThreads and reports 5686 their thread IDs so that the user can configure host CPU 5687 pinning/affinity. 5688 5689 IOThreads use an adaptive polling algorithm to reduce event loop 5690 latency. Instead of entering a blocking system call to monitor 5691 file descriptors and then pay the cost of being woken up when an 5692 event occurs, the polling algorithm spins waiting for events for 5693 a short time. The algorithm's default parameters are suitable 5694 for many cases but can be adjusted based on knowledge of the 5695 workload and/or host device latency. 5696 5697 The ``poll-max-ns`` parameter is the maximum number of 5698 nanoseconds to busy wait for events. Polling can be disabled by 5699 setting this value to 0. 5700 5701 The ``poll-grow`` parameter is the multiplier used to increase 5702 the polling time when the algorithm detects it is missing events 5703 due to not polling long enough. 5704 5705 The ``poll-shrink`` parameter is the divisor used to decrease 5706 the polling time when the algorithm detects it is spending too 5707 long polling without encountering events. 5708 5709 The ``aio-max-batch`` parameter is the maximum number of requests 5710 in a batch for the AIO engine, 0 means that the engine will use 5711 its default. 5712 5713 The IOThread parameters can be modified at run-time using the 5714 ``qom-set`` command (where ``iothread1`` is the IOThread's 5715 ``id``): 5716 5717 :: 5718 5719 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5720ERST 5721 5722 5723HXCOMM This is the last statement. Insert new options before this line! 5724 5725#undef DEF 5726#undef DEFHEADING 5727#undef ARCHHEADING 5728
