1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST version and 3HXCOMM discarded from C version. 4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 5HXCOMM construct option structures, enums and help message for specified 6HXCOMM architectures. 7HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hax, hvf, nvmm, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 40 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 41 QEMU_ARCH_ALL) 42SRST 43``-machine [type=]name[,prop=value[,...]]`` 44 Select the emulated machine by name. Use ``-machine help`` to list 45 available machines. 46 47 For architectures which aim to support live migration compatibility 48 across releases, each release will introduce a new versioned machine 49 type. For example, the 2.8.0 release introduced machine types 50 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 51 52 To allow live migration of guests from QEMU version 2.8.0, to QEMU 53 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 54 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 55 skip multiple intermediate releases when upgrading, new releases of 56 QEMU will support machine types from many previous versions. 57 58 Supported machine properties are: 59 60 ``accel=accels1[:accels2[:...]]`` 61 This is used to enable an accelerator. Depending on the target 62 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 63 By default, tcg is used. If there is more than one accelerator 64 specified, the next one is used if the previous one fails to 65 initialize. 66 67 ``vmport=on|off|auto`` 68 Enables emulation of VMWare IO port, for vmmouse etc. auto says 69 to select the value based on accel. For accel=xen the default is 70 off otherwise the default is on. 71 72 ``dump-guest-core=on|off`` 73 Include guest memory in a core dump. The default is on. 74 75 ``mem-merge=on|off`` 76 Enables or disables memory merge support. This feature, when 77 supported by the host, de-duplicates identical memory pages 78 among VMs instances (enabled by default). 79 80 ``aes-key-wrap=on|off`` 81 Enables or disables AES key wrapping support on s390-ccw hosts. 82 This feature controls whether AES wrapping keys will be created 83 to allow execution of AES cryptographic functions. The default 84 is on. 85 86 ``dea-key-wrap=on|off`` 87 Enables or disables DEA key wrapping support on s390-ccw hosts. 88 This feature controls whether DEA wrapping keys will be created 89 to allow execution of DEA cryptographic functions. The default 90 is on. 91 92 ``nvdimm=on|off`` 93 Enables or disables NVDIMM support. The default is off. 94 95 ``memory-encryption=`` 96 Memory encryption object to use. The default is none. 97 98 ``hmat=on|off`` 99 Enables or disables ACPI Heterogeneous Memory Attribute Table 100 (HMAT) support. The default is off. 101 102 ``memory-backend='id'`` 103 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 104 Allows to use a memory backend as main RAM. 105 106 For example: 107 :: 108 109 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 110 -machine memory-backend=pc.ram 111 -m 512M 112 113 Migration compatibility note: 114 115 * as backend id one shall use value of 'default-ram-id', advertised by 116 machine type (available via ``query-machines`` QMP command), if migration 117 to/from old QEMU (<5.0) is expected. 118 * for machine types 4.0 and older, user shall 119 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 120 if migration to/from old QEMU (<5.0) is expected. 121 122 For example: 123 :: 124 125 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 126 -machine memory-backend=pc.ram 127 -m 512M 128 129 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 130 Define a CXL Fixed Memory Window (CFMW). 131 132 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 133 134 They are regions of Host Physical Addresses (HPA) on a system which 135 may be interleaved across one or more CXL host bridges. The system 136 software will assign particular devices into these windows and 137 configure the downstream Host-managed Device Memory (HDM) decoders 138 in root ports, switch ports and devices appropriately to meet the 139 interleave requirements before enabling the memory devices. 140 141 ``targets.X=target`` provides the mapping to CXL host bridges 142 which may be identified by the id provided in the -device entry. 143 Multiple entries are needed to specify all the targets when 144 the fixed memory window represents interleaved memory. X is the 145 target index from 0. 146 147 ``size=size`` sets the size of the CFMW. This must be a multiple of 148 256MiB. The region will be aligned to 256MiB but the location is 149 platform and configuration dependent. 150 151 ``interleave-granularity=granularity`` sets the granularity of 152 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 153 4096KiB, 8192KiB and 16384KiB granularities supported. 154 155 Example: 156 157 :: 158 159 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k 160ERST 161 162DEF("M", HAS_ARG, QEMU_OPTION_M, 163 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 164 QEMU_ARCH_ALL) 165 166SRST 167``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 168 Define an SGX EPC section. 169ERST 170 171DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 172 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 173SRST 174``-cpu model`` 175 Select CPU model (``-cpu help`` for list and additional feature 176 selection) 177ERST 178 179DEF("accel", HAS_ARG, QEMU_OPTION_accel, 180 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 181 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 182 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 183 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 184 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 185 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 186 " split-wx=on|off (enable TCG split w^x mapping)\n" 187 " tb-size=n (TCG translation block cache size)\n" 188 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 189 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 190 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 191SRST 192``-accel name[,prop=value[,...]]`` 193 This is used to enable an accelerator. Depending on the target 194 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 195 default, tcg is used. If there is more than one accelerator 196 specified, the next one is used if the previous one fails to 197 initialize. 198 199 ``igd-passthru=on|off`` 200 When Xen is in use, this option controls whether Intel 201 integrated graphics devices can be passed through to the guest 202 (default=off) 203 204 ``kernel-irqchip=on|off|split`` 205 Controls KVM in-kernel irqchip support. The default is full 206 acceleration of the interrupt controllers. On x86, split irqchip 207 reduces the kernel attack surface, at a performance cost for 208 non-MSI interrupts. Disabling the in-kernel irqchip completely 209 is not recommended except for debugging purposes. 210 211 ``kvm-shadow-mem=size`` 212 Defines the size of the KVM shadow MMU. 213 214 ``one-insn-per-tb=on|off`` 215 Makes the TCG accelerator put only one guest instruction into 216 each translation block. This slows down emulation a lot, but 217 can be useful in some situations, such as when trying to analyse 218 the logs produced by the ``-d`` option. 219 220 ``split-wx=on|off`` 221 Controls the use of split w^x mapping for the TCG code generation 222 buffer. Some operating systems require this to be enabled, and in 223 such a case this will default on. On other operating systems, this 224 will default off, but one may enable this for testing or debugging. 225 226 ``tb-size=n`` 227 Controls the size (in MiB) of the TCG translation block cache. 228 229 ``thread=single|multi`` 230 Controls number of TCG threads. When the TCG is multi-threaded 231 there will be one thread per vCPU therefore taking advantage of 232 additional host cores. The default is to enable multi-threading 233 where both the back-end and front-ends support it and no 234 incompatible TCG features have been enabled (e.g. 235 icount/replay). 236 237 ``dirty-ring-size=n`` 238 When the KVM accelerator is used, it controls the size of the per-vCPU 239 dirty page ring buffer (number of entries for each vCPU). It should 240 be a value that is power of two, and it should be 1024 or bigger (but 241 still less than the maximum value that the kernel supports). 4096 242 could be a good initial value if you have no idea which is the best. 243 Set this value to 0 to disable the feature. By default, this feature 244 is disabled (dirty-ring-size=0). When enabled, KVM will instead 245 record dirty pages in a bitmap. 246 247 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 248 Enables or disables notify VM exit support on x86 host and specify 249 the corresponding notify window to trigger the VM exit if enabled. 250 ``run`` option enables the feature. It does nothing and continue 251 if the exit happens. ``internal-error`` option enables the feature. 252 It raises a internal error. ``disable`` option doesn't enable the feature. 253 This feature can mitigate the CPU stuck issue due to event windows don't 254 open up for a specified of time (i.e. notify-window). 255 Default: notify-vmexit=run,notify-window=0. 256 257ERST 258 259DEF("smp", HAS_ARG, QEMU_OPTION_smp, 260 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 261 " set the number of initial CPUs to 'n' [default=1]\n" 262 " maxcpus= maximum number of total CPUs, including\n" 263 " offline CPUs for hotplug, etc\n" 264 " sockets= number of sockets on the machine board\n" 265 " dies= number of dies in one socket\n" 266 " clusters= number of clusters in one die\n" 267 " cores= number of cores in one cluster\n" 268 " threads= number of threads in one core\n" 269 "Note: Different machines may have different subsets of the CPU topology\n" 270 " parameters supported, so the actual meaning of the supported parameters\n" 271 " will vary accordingly. For example, for a machine type that supports a\n" 272 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 273 " sequentially mean as below:\n" 274 " sockets means the number of sockets on the machine board\n" 275 " cores means the number of cores in one socket\n" 276 " threads means the number of threads in one core\n" 277 " For a particular machine type board, an expected CPU topology hierarchy\n" 278 " can be defined through the supported sub-option. Unsupported parameters\n" 279 " can also be provided in addition to the sub-option, but their values\n" 280 " must be set as 1 in the purpose of correct parsing.\n", 281 QEMU_ARCH_ALL) 282SRST 283``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 284 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 285 the machine type board. On boards supporting CPU hotplug, the optional 286 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 287 added at runtime. When both parameters are omitted, the maximum number 288 of CPUs will be calculated from the provided topology members and the 289 initial CPU count will match the maximum number. When only one of them 290 is given then the omitted one will be set to its counterpart's value. 291 Both parameters may be specified, but the maximum number of CPUs must 292 be equal to or greater than the initial CPU count. Product of the 293 CPU topology hierarchy must be equal to the maximum number of CPUs. 294 Both parameters are subject to an upper limit that is determined by 295 the specific machine type chosen. 296 297 To control reporting of CPU topology information, values of the topology 298 parameters can be specified. Machines may only support a subset of the 299 parameters and different machines may have different subsets supported 300 which vary depending on capacity of the corresponding CPU targets. So 301 for a particular machine type board, an expected topology hierarchy can 302 be defined through the supported sub-option. Unsupported parameters can 303 also be provided in addition to the sub-option, but their values must be 304 set as 1 in the purpose of correct parsing. 305 306 Either the initial CPU count, or at least one of the topology parameters 307 must be specified. The specified parameters must be greater than zero, 308 explicit configuration like "cpus=0" is not allowed. Values for any 309 omitted parameters will be computed from those which are given. 310 311 For example, the following sub-option defines a CPU topology hierarchy 312 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 313 core) for a machine that only supports sockets/cores/threads. 314 Some members of the option can be omitted but their values will be 315 automatically computed: 316 317 :: 318 319 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 320 321 The following sub-option defines a CPU topology hierarchy (2 sockets 322 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 323 per core) for PC machines which support sockets/dies/cores/threads. 324 Some members of the option can be omitted but their values will be 325 automatically computed: 326 327 :: 328 329 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 330 331 The following sub-option defines a CPU topology hierarchy (2 sockets 332 totally on the machine, 2 clusters per socket, 2 cores per cluster, 333 2 threads per core) for ARM virt machines which support sockets/clusters 334 /cores/threads. Some members of the option can be omitted but their values 335 will be automatically computed: 336 337 :: 338 339 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 340 341 Historically preference was given to the coarsest topology parameters 342 when computing missing values (ie sockets preferred over cores, which 343 were preferred over threads), however, this behaviour is considered 344 liable to change. Prior to 6.2 the preference was sockets over cores 345 over threads. Since 6.2 the preference is cores over sockets over threads. 346 347 For example, the following option defines a machine board with 2 sockets 348 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 349 350 :: 351 352 -smp 2 353 354 Note: The cluster topology will only be generated in ACPI and exposed 355 to guest if it's explicitly specified in -smp. 356ERST 357 358DEF("numa", HAS_ARG, QEMU_OPTION_numa, 359 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 360 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 361 "-numa dist,src=source,dst=destination,val=distance\n" 362 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 363 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n" 364 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 365 QEMU_ARCH_ALL) 366SRST 367``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 368 \ 369``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 370 \ 371``-numa dist,src=source,dst=destination,val=distance`` 372 \ 373``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 374 \ 375``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 376 \ 377``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 378 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 379 distance from a source node to a destination node. Set the ACPI 380 Heterogeneous Memory Attributes for the given nodes. 381 382 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 383 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 384 contiguous range of CPU indexes (or a single VCPU if lastcpu is 385 omitted). A non-contiguous set of VCPUs can be represented by 386 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 387 omitted on all nodes, VCPUs are automatically split between them. 388 389 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 390 NUMA node: 391 392 :: 393 394 -numa node,cpus=0-2,cpus=5 395 396 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 397 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 398 assign CPU objects to a node using topology layout properties of 399 CPU. The set of properties is machine specific, and depends on used 400 machine type/'\ ``smp``\ ' options. It could be queried with 401 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 402 property specifies node to which CPU object will be assigned, it's 403 required for node to be declared with '\ ``node``\ ' option before 404 it's used with '\ ``cpu``\ ' option. 405 406 For example: 407 408 :: 409 410 -M pc \ 411 -smp 1,sockets=2,maxcpus=2 \ 412 -numa node,nodeid=0 -numa node,nodeid=1 \ 413 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 414 415 '\ ``memdev``\ ' option assigns RAM from a given memory backend 416 device to a node. It is recommended to use '\ ``memdev``\ ' option 417 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 418 option provides better performance and more control over the 419 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 420 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 421 422 For compatibility reasons, legacy '\ ``mem``\ ' option is 423 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 424 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 425 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 426 option, and vice versa. 427 428 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 429 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 430 for '\ ``-numa node``\ ' without memory specified was removed. 431 432 '\ ``initiator``\ ' is an additional option that points to an 433 initiator NUMA node that has best performance (the lowest latency or 434 largest bandwidth) to this NUMA node. Note that this option can be 435 set only when the machine property 'hmat' is set to 'on'. 436 437 Following example creates a machine with 2 NUMA nodes, node 0 has 438 CPU. node 1 has only memory, and its initiator is node 0. Note that 439 because node 0 has CPU, by default the initiator of node 0 is itself 440 and must be itself. 441 442 :: 443 444 -machine hmat=on \ 445 -m 2G,slots=2,maxmem=4G \ 446 -object memory-backend-ram,size=1G,id=m0 \ 447 -object memory-backend-ram,size=1G,id=m1 \ 448 -numa node,nodeid=0,memdev=m0 \ 449 -numa node,nodeid=1,memdev=m1,initiator=0 \ 450 -smp 2,sockets=2,maxcpus=2 \ 451 -numa cpu,node-id=0,socket-id=0 \ 452 -numa cpu,node-id=0,socket-id=1 453 454 source and destination are NUMA node IDs. distance is the NUMA 455 distance from source to destination. The distance from a node to 456 itself is always 10. If any pair of nodes is given a distance, then 457 all pairs must be given distances. Although, when distances are only 458 given in one direction for each pair of nodes, then the distances in 459 the opposite directions are assumed to be the same. If, however, an 460 asymmetrical pair of distances is given for even one node pair, then 461 all node pairs must be provided distance values for both directions, 462 even when they are symmetrical. When a node is unreachable from 463 another node, set the pair's distance to 255. 464 465 Note that the -``numa`` option doesn't allocate any of the specified 466 resources, it just assigns existing resources to NUMA nodes. This 467 means that one still has to use the ``-m``, ``-smp`` options to 468 allocate RAM and VCPUs respectively. 469 470 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 471 Information between initiator and target NUMA nodes in ACPI 472 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 473 create memory requests, usually it has one or more processors. 474 Target NUMA node contains addressable memory. 475 476 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 477 the memory hierarchy of the target NUMA node: if hierarchy is 478 'memory', the structure represents the memory performance; if 479 hierarchy is 'first-level\|second-level\|third-level', this 480 structure represents aggregated performance of memory side caches 481 for each domain. type of 'data-type' is type of data represented by 482 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 483 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 484 the target memory; if 'hierarchy' is 485 'first-level\|second-level\|third-level', 'data-type' is 486 'access\|read\|write' hit latency or 'access\|read\|write' hit 487 bandwidth of the target memory side cache. 488 489 lat is latency value in nanoseconds. bw is bandwidth value, the 490 possible value and units are NUM[M\|G\|T], mean that the bandwidth 491 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 492 used suffix). Note that if latency or bandwidth value is 0, means 493 the corresponding latency or bandwidth information is not provided. 494 495 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 496 belongs. size is the size of memory side cache in bytes. level is 497 the cache level described in this structure, note that the cache 498 level 0 should not be used with '\ ``hmat-cache``\ ' option. 499 associativity is the cache associativity, the possible value is 500 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 501 is the write policy. line is the cache Line size in bytes. 502 503 For example, the following options describe 2 NUMA nodes. Node 0 has 504 2 cpus and a ram, node 1 has only a ram. The processors in node 0 505 access memory in node 0 with access-latency 5 nanoseconds, 506 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 507 memory in NUMA node 1 with access-latency 10 nanoseconds, 508 access-bandwidth is 100 MB/s. And for memory side cache information, 509 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 510 policy is write-back, the cache Line size is 8 bytes: 511 512 :: 513 514 -machine hmat=on \ 515 -m 2G \ 516 -object memory-backend-ram,size=1G,id=m0 \ 517 -object memory-backend-ram,size=1G,id=m1 \ 518 -smp 2,sockets=2,maxcpus=2 \ 519 -numa node,nodeid=0,memdev=m0 \ 520 -numa node,nodeid=1,memdev=m1,initiator=0 \ 521 -numa cpu,node-id=0,socket-id=0 \ 522 -numa cpu,node-id=0,socket-id=1 \ 523 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 524 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 525 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 526 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 527 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 528 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 529ERST 530 531DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 532 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 533 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 534SRST 535``-add-fd fd=fd,set=set[,opaque=opaque]`` 536 Add a file descriptor to an fd set. Valid options are: 537 538 ``fd=fd`` 539 This option defines the file descriptor of which a duplicate is 540 added to fd set. The file descriptor cannot be stdin, stdout, or 541 stderr. 542 543 ``set=set`` 544 This option defines the ID of the fd set to add the file 545 descriptor to. 546 547 ``opaque=opaque`` 548 This option defines a free-form string that can be used to 549 describe fd. 550 551 You can open an image using pre-opened file descriptors from an fd 552 set: 553 554 .. parsed-literal:: 555 556 |qemu_system| \\ 557 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 558 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 559 -drive file=/dev/fdset/2,index=0,media=disk 560ERST 561 562DEF("set", HAS_ARG, QEMU_OPTION_set, 563 "-set group.id.arg=value\n" 564 " set <arg> parameter for item <id> of type <group>\n" 565 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 566SRST 567``-set group.id.arg=value`` 568 Set parameter arg for item id of type group 569ERST 570 571DEF("global", HAS_ARG, QEMU_OPTION_global, 572 "-global driver.property=value\n" 573 "-global driver=driver,property=property,value=value\n" 574 " set a global default for a driver property\n", 575 QEMU_ARCH_ALL) 576SRST 577``-global driver.prop=value`` 578 \ 579``-global driver=driver,property=property,value=value`` 580 Set default value of driver's property prop to value, e.g.: 581 582 .. parsed-literal:: 583 584 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 585 586 In particular, you can use this to set driver properties for devices 587 which are created automatically by the machine model. To create a 588 device which is not created automatically and set properties on it, 589 use -``device``. 590 591 -global driver.prop=value is shorthand for -global 592 driver=driver,property=prop,value=value. The longhand syntax works 593 even when driver contains a dot. 594ERST 595 596DEF("boot", HAS_ARG, QEMU_OPTION_boot, 597 "-boot [order=drives][,once=drives][,menu=on|off]\n" 598 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 599 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 600 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 601 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 602 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 603 QEMU_ARCH_ALL) 604SRST 605``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 606 Specify boot order drives as a string of drive letters. Valid drive 607 letters depend on the target architecture. The x86 PC uses: a, b 608 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 609 (Etherboot from network adapter 1-4), hard disk boot is the default. 610 To apply a particular boot order only on the first startup, specify 611 it via ``once``. Note that the ``order`` or ``once`` parameter 612 should not be used together with the ``bootindex`` property of 613 devices, since the firmware implementations normally do not support 614 both at the same time. 615 616 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 617 as firmware/BIOS supports them. The default is non-interactive boot. 618 619 A splash picture could be passed to bios, enabling user to show it 620 as logo, when option splash=sp\_name is given and menu=on, If 621 firmware/BIOS supports them. Currently Seabios for X86 system 622 support it. limitation: The splash file could be a jpeg file or a 623 BMP file in 24 BPP format(true color). The resolution should be 624 supported by the SVGA mode, so the recommended is 320x240, 640x480, 625 800x640. 626 627 A timeout could be passed to bios, guest will pause for rb\_timeout 628 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 629 not reboot, qemu passes '-1' to bios by default. Currently Seabios 630 for X86 system support it. 631 632 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 633 it. This only effects when boot priority is changed by bootindex 634 options. The default is non-strict boot. 635 636 .. parsed-literal:: 637 638 # try to boot from network first, then from hard disk 639 |qemu_system_x86| -boot order=nc 640 # boot from CD-ROM first, switch back to default order after reboot 641 |qemu_system_x86| -boot once=d 642 # boot with a splash picture for 5 seconds. 643 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 644 645 Note: The legacy format '-boot drives' is still supported but its 646 use is discouraged as it may be removed from future versions. 647ERST 648 649DEF("m", HAS_ARG, QEMU_OPTION_m, 650 "-m [size=]megs[,slots=n,maxmem=size]\n" 651 " configure guest RAM\n" 652 " size: initial amount of guest memory\n" 653 " slots: number of hotplug slots (default: none)\n" 654 " maxmem: maximum amount of guest memory (default: none)\n" 655 "NOTE: Some architectures might enforce a specific granularity\n", 656 QEMU_ARCH_ALL) 657SRST 658``-m [size=]megs[,slots=n,maxmem=size]`` 659 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 660 Optionally, a suffix of "M" or "G" can be used to signify a value in 661 megabytes or gigabytes respectively. Optional pair slots, maxmem 662 could be used to set amount of hotpluggable memory slots and maximum 663 amount of memory. Note that maxmem must be aligned to the page size. 664 665 For example, the following command-line sets the guest startup RAM 666 size to 1GB, creates 3 slots to hotplug additional memory and sets 667 the maximum memory the guest can reach to 4GB: 668 669 .. parsed-literal:: 670 671 |qemu_system| -m 1G,slots=3,maxmem=4G 672 673 If slots and maxmem are not specified, memory hotplug won't be 674 enabled and the guest startup RAM will never increase. 675ERST 676 677DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 678 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 679SRST 680``-mem-path path`` 681 Allocate guest RAM from a temporarily created file in path. 682ERST 683 684DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 685 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 686 QEMU_ARCH_ALL) 687SRST 688``-mem-prealloc`` 689 Preallocate memory when using -mem-path. 690ERST 691 692DEF("k", HAS_ARG, QEMU_OPTION_k, 693 "-k language use keyboard layout (for example 'fr' for French)\n", 694 QEMU_ARCH_ALL) 695SRST 696``-k language`` 697 Use keyboard layout language (for example ``fr`` for French). This 698 option is only needed where it is not easy to get raw PC keycodes 699 (e.g. on Macs, with some X11 servers or with a VNC or curses 700 display). You don't normally need to use it on PC/Linux or 701 PC/Windows hosts. 702 703 The available layouts are: 704 705 :: 706 707 ar de-ch es fo fr-ca hu ja mk no pt-br sv 708 da en-gb et fr fr-ch is lt nl pl ru th 709 de en-us fi fr-be hr it lv nl-be pt sl tr 710 711 The default is ``en-us``. 712ERST 713 714 715HXCOMM Deprecated by -audiodev 716DEF("audio-help", 0, QEMU_OPTION_audio_help, 717 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 718 QEMU_ARCH_ALL) 719SRST 720``-audio-help`` 721 Will show the -audiodev equivalent of the currently specified 722 (deprecated) environment variables. 723ERST 724 725DEF("audio", HAS_ARG, QEMU_OPTION_audio, 726 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 727 " specifies the audio backend and device to use;\n" 728 " apart from 'model', options are the same as for -audiodev.\n" 729 " use '-audio model=help' to show possible devices.\n", 730 QEMU_ARCH_ALL) 731SRST 732``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 733 This option is a shortcut for configuring both the guest audio 734 hardware and the host audio backend in one go. 735 The driver option is the same as with the corresponding ``-audiodev`` option below. 736 The guest hardware model can be set with ``model=modelname``. 737 738 Use ``driver=help`` to list the available drivers, 739 and ``model=help`` to list the available device types. 740 741 The following two example do exactly the same, to show how ``-audio`` 742 can be used to shorten the command line length: 743 744 .. parsed-literal:: 745 746 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 747 |qemu_system| -audio pa,model=sb16 748ERST 749 750DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 751 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 752 " specifies the audio backend to use\n" 753 " Use ``-audiodev help`` to list the available drivers\n" 754 " id= identifier of the backend\n" 755 " timer-period= timer period in microseconds\n" 756 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 757 " in|out.fixed-settings= use fixed settings for host audio\n" 758 " in|out.frequency= frequency to use with fixed settings\n" 759 " in|out.channels= number of channels to use with fixed settings\n" 760 " in|out.format= sample format to use with fixed settings\n" 761 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 762 " in|out.voices= number of voices to use\n" 763 " in|out.buffer-length= length of buffer in microseconds\n" 764 "-audiodev none,id=id,[,prop[=value][,...]]\n" 765 " dummy driver that discards all output\n" 766#ifdef CONFIG_AUDIO_ALSA 767 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 768 " in|out.dev= name of the audio device to use\n" 769 " in|out.period-length= length of period in microseconds\n" 770 " in|out.try-poll= attempt to use poll mode\n" 771 " threshold= threshold (in microseconds) when playback starts\n" 772#endif 773#ifdef CONFIG_AUDIO_COREAUDIO 774 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 775 " in|out.buffer-count= number of buffers\n" 776#endif 777#ifdef CONFIG_AUDIO_DSOUND 778 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 779 " latency= add extra latency to playback in microseconds\n" 780#endif 781#ifdef CONFIG_AUDIO_OSS 782 "-audiodev oss,id=id[,prop[=value][,...]]\n" 783 " in|out.dev= path of the audio device to use\n" 784 " in|out.buffer-count= number of buffers\n" 785 " in|out.try-poll= attempt to use poll mode\n" 786 " try-mmap= try using memory mapped access\n" 787 " exclusive= open device in exclusive mode\n" 788 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 789#endif 790#ifdef CONFIG_AUDIO_PA 791 "-audiodev pa,id=id[,prop[=value][,...]]\n" 792 " server= PulseAudio server address\n" 793 " in|out.name= source/sink device name\n" 794 " in|out.latency= desired latency in microseconds\n" 795#endif 796#ifdef CONFIG_AUDIO_PIPEWIRE 797 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 798 " in|out.name= source/sink device name\n" 799 " in|out.stream-name= name of pipewire stream\n" 800 " in|out.latency= desired latency in microseconds\n" 801#endif 802#ifdef CONFIG_AUDIO_SDL 803 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 804 " in|out.buffer-count= number of buffers\n" 805#endif 806#ifdef CONFIG_AUDIO_SNDIO 807 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 808#endif 809#ifdef CONFIG_SPICE 810 "-audiodev spice,id=id[,prop[=value][,...]]\n" 811#endif 812#ifdef CONFIG_DBUS_DISPLAY 813 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 814#endif 815 "-audiodev wav,id=id[,prop[=value][,...]]\n" 816 " path= path of wav file to record\n", 817 QEMU_ARCH_ALL) 818SRST 819``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 820 Adds a new audio backend driver identified by id. There are global 821 and driver specific properties. Some values can be set differently 822 for input and output, they're marked with ``in|out.``. You can set 823 the input's property with ``in.prop`` and the output's property with 824 ``out.prop``. For example: 825 826 :: 827 828 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 829 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 830 831 NOTE: parameter validation is known to be incomplete, in many cases 832 specifying an invalid option causes QEMU to print an error message 833 and continue emulation without sound. 834 835 Valid global options are: 836 837 ``id=identifier`` 838 Identifies the audio backend. 839 840 ``timer-period=period`` 841 Sets the timer period used by the audio subsystem in 842 microseconds. Default is 10000 (10 ms). 843 844 ``in|out.mixing-engine=on|off`` 845 Use QEMU's mixing engine to mix all streams inside QEMU and 846 convert audio formats when not supported by the backend. When 847 off, fixed-settings must be off too. Note that disabling this 848 option means that the selected backend must support multiple 849 streams and the audio formats used by the virtual cards, 850 otherwise you'll get no sound. It's not recommended to disable 851 this option unless you want to use 5.1 or 7.1 audio, as mixing 852 engine only supports mono and stereo audio. Default is on. 853 854 ``in|out.fixed-settings=on|off`` 855 Use fixed settings for host audio. When off, it will change 856 based on how the guest opens the sound card. In this case you 857 must not specify frequency, channels or format. Default is on. 858 859 ``in|out.frequency=frequency`` 860 Specify the frequency to use when using fixed-settings. Default 861 is 44100Hz. 862 863 ``in|out.channels=channels`` 864 Specify the number of channels to use when using fixed-settings. 865 Default is 2 (stereo). 866 867 ``in|out.format=format`` 868 Specify the sample format to use when using fixed-settings. 869 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 870 ``u32``, ``f32``. Default is ``s16``. 871 872 ``in|out.voices=voices`` 873 Specify the number of voices to use. Default is 1. 874 875 ``in|out.buffer-length=usecs`` 876 Sets the size of the buffer in microseconds. 877 878``-audiodev none,id=id[,prop[=value][,...]]`` 879 Creates a dummy backend that discards all outputs. This backend has 880 no backend specific properties. 881 882``-audiodev alsa,id=id[,prop[=value][,...]]`` 883 Creates backend using the ALSA. This backend is only available on 884 Linux. 885 886 ALSA specific options are: 887 888 ``in|out.dev=device`` 889 Specify the ALSA device to use for input and/or output. Default 890 is ``default``. 891 892 ``in|out.period-length=usecs`` 893 Sets the period length in microseconds. 894 895 ``in|out.try-poll=on|off`` 896 Attempt to use poll mode with the device. Default is on. 897 898 ``threshold=threshold`` 899 Threshold (in microseconds) when playback starts. Default is 0. 900 901``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 902 Creates a backend using Apple's Core Audio. This backend is only 903 available on Mac OS and only supports playback. 904 905 Core Audio specific options are: 906 907 ``in|out.buffer-count=count`` 908 Sets the count of the buffers. 909 910``-audiodev dsound,id=id[,prop[=value][,...]]`` 911 Creates a backend using Microsoft's DirectSound. This backend is 912 only available on Windows and only supports playback. 913 914 DirectSound specific options are: 915 916 ``latency=usecs`` 917 Add extra usecs microseconds latency to playback. Default is 918 10000 (10 ms). 919 920``-audiodev oss,id=id[,prop[=value][,...]]`` 921 Creates a backend using OSS. This backend is available on most 922 Unix-like systems. 923 924 OSS specific options are: 925 926 ``in|out.dev=device`` 927 Specify the file name of the OSS device to use. Default is 928 ``/dev/dsp``. 929 930 ``in|out.buffer-count=count`` 931 Sets the count of the buffers. 932 933 ``in|out.try-poll=on|of`` 934 Attempt to use poll mode with the device. Default is on. 935 936 ``try-mmap=on|off`` 937 Try using memory mapped device access. Default is off. 938 939 ``exclusive=on|off`` 940 Open the device in exclusive mode (vmix won't work in this 941 case). Default is off. 942 943 ``dsp-policy=policy`` 944 Sets the timing policy (between 0 and 10, where smaller number 945 means smaller latency but higher CPU usage). Use -1 to use 946 buffer sizes specified by ``buffer`` and ``buffer-count``. This 947 option is ignored if you do not have OSS 4. Default is 5. 948 949``-audiodev pa,id=id[,prop[=value][,...]]`` 950 Creates a backend using PulseAudio. This backend is available on 951 most systems. 952 953 PulseAudio specific options are: 954 955 ``server=server`` 956 Sets the PulseAudio server to connect to. 957 958 ``in|out.name=sink`` 959 Use the specified source/sink for recording/playback. 960 961 ``in|out.latency=usecs`` 962 Desired latency in microseconds. The PulseAudio server will try 963 to honor this value but actual latencies may be lower or higher. 964 965``-audiodev pipewire,id=id[,prop[=value][,...]]`` 966 Creates a backend using Pipewire. This backend is available on 967 most systems. 968 969 Pipewire specific options are: 970 971 ``in|out.latency=usecs`` 972 Desired latency in microseconds. 973 974 ``in|out.name=sink`` 975 Use the specified source/sink for recording/playback. 976 977 ``in|out.stream-name`` 978 Specify the name of pipewire stream. 979 980``-audiodev sdl,id=id[,prop[=value][,...]]`` 981 Creates a backend using SDL. This backend is available on most 982 systems, but you should use your platform's native backend if 983 possible. 984 985 SDL specific options are: 986 987 ``in|out.buffer-count=count`` 988 Sets the count of the buffers. 989 990``-audiodev sndio,id=id[,prop[=value][,...]]`` 991 Creates a backend using SNDIO. This backend is available on 992 OpenBSD and most other Unix-like systems. 993 994 Sndio specific options are: 995 996 ``in|out.dev=device`` 997 Specify the sndio device to use for input and/or output. Default 998 is ``default``. 999 1000 ``in|out.latency=usecs`` 1001 Sets the desired period length in microseconds. 1002 1003``-audiodev spice,id=id[,prop[=value][,...]]`` 1004 Creates a backend that sends audio through SPICE. This backend 1005 requires ``-spice`` and automatically selected in that case, so 1006 usually you can ignore this option. This backend has no backend 1007 specific properties. 1008 1009``-audiodev wav,id=id[,prop[=value][,...]]`` 1010 Creates a backend that writes audio to a WAV file. 1011 1012 Backend specific options are: 1013 1014 ``path=path`` 1015 Write recorded audio into the specified file. Default is 1016 ``qemu.wav``. 1017ERST 1018 1019DEF("device", HAS_ARG, QEMU_OPTION_device, 1020 "-device driver[,prop[=value][,...]]\n" 1021 " add device (based on driver)\n" 1022 " prop=value,... sets driver properties\n" 1023 " use '-device help' to print all possible drivers\n" 1024 " use '-device driver,help' to print all possible properties\n", 1025 QEMU_ARCH_ALL) 1026SRST 1027``-device driver[,prop[=value][,...]]`` 1028 Add device driver. prop=value sets driver properties. Valid 1029 properties depend on the driver. To get help on possible drivers and 1030 properties, use ``-device help`` and ``-device driver,help``. 1031 1032 Some drivers are: 1033 1034``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1035 Add an IPMI BMC. This is a simulation of a hardware management 1036 interface processor that normally sits on a system. It provides a 1037 watchdog and the ability to reset and power control the system. You 1038 need to connect this to an IPMI interface to make it useful 1039 1040 The IPMI slave address to use for the BMC. The default is 0x20. This 1041 address is the BMC's address on the I2C network of management 1042 controllers. If you don't know what this means, it is safe to ignore 1043 it. 1044 1045 ``id=id`` 1046 The BMC id for interfaces to use this device. 1047 1048 ``slave_addr=val`` 1049 Define slave address to use for the BMC. The default is 0x20. 1050 1051 ``sdrfile=file`` 1052 file containing raw Sensor Data Records (SDR) data. The default 1053 is none. 1054 1055 ``fruareasize=val`` 1056 size of a Field Replaceable Unit (FRU) area. The default is 1057 1024. 1058 1059 ``frudatafile=file`` 1060 file containing raw Field Replaceable Unit (FRU) inventory data. 1061 The default is none. 1062 1063 ``guid=uuid`` 1064 value for the GUID for the BMC, in standard UUID format. If this 1065 is set, get "Get GUID" command to the BMC will return it. 1066 Otherwise "Get GUID" will return an error. 1067 1068``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1069 Add a connection to an external IPMI BMC simulator. Instead of 1070 locally emulating the BMC like the above item, instead connect to an 1071 external entity that provides the IPMI services. 1072 1073 A connection is made to an external BMC simulator. If you do this, 1074 it is strongly recommended that you use the "reconnect=" chardev 1075 option to reconnect to the simulator if the connection is lost. Note 1076 that if this is not used carefully, it can be a security issue, as 1077 the interface has the ability to send resets, NMIs, and power off 1078 the VM. It's best if QEMU makes a connection to an external 1079 simulator running on a secure port on localhost, so neither the 1080 simulator nor QEMU is exposed to any outside network. 1081 1082 See the "lanserv/README.vm" file in the OpenIPMI library for more 1083 details on the external interface. 1084 1085``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1086 Add a KCS IPMI interface on the ISA bus. This also adds a 1087 corresponding ACPI and SMBIOS entries, if appropriate. 1088 1089 ``bmc=id`` 1090 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1091 above. 1092 1093 ``ioport=val`` 1094 Define the I/O address of the interface. The default is 0xca0 1095 for KCS. 1096 1097 ``irq=val`` 1098 Define the interrupt to use. The default is 5. To disable 1099 interrupts, set this to 0. 1100 1101``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1102 Like the KCS interface, but defines a BT interface. The default port 1103 is 0xe4 and the default interrupt is 5. 1104 1105``-device pci-ipmi-kcs,bmc=id`` 1106 Add a KCS IPMI interface on the PCI bus. 1107 1108 ``bmc=id`` 1109 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1110 1111``-device pci-ipmi-bt,bmc=id`` 1112 Like the KCS interface, but defines a BT interface on the PCI bus. 1113 1114``-device intel-iommu[,option=...]`` 1115 This is only supported by ``-machine q35``, which will enable Intel VT-d 1116 emulation within the guest. It supports below options: 1117 1118 ``intremap=on|off`` (default: auto) 1119 This enables interrupt remapping feature. It's required to enable 1120 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1121 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1122 The default value is "auto", which will be decided by the mode of 1123 kernel-irqchip. 1124 1125 ``caching-mode=on|off`` (default: off) 1126 This enables caching mode for the VT-d emulated device. When 1127 caching-mode is enabled, each guest DMA buffer mapping will generate an 1128 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1129 a synchronous way. It is required for ``-device vfio-pci`` to work 1130 with the VT-d device, because host assigned devices requires to setup 1131 the DMA mapping on the host before guest DMA starts. 1132 1133 ``device-iotlb=on|off`` (default: off) 1134 This enables device-iotlb capability for the emulated VT-d device. So 1135 far virtio/vhost should be the only real user for this parameter, 1136 paired with ats=on configured for the device. 1137 1138 ``aw-bits=39|48`` (default: 39) 1139 This decides the address width of IOVA address space. The address 1140 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1141 4-level IOMMU page tables. 1142 1143 Please also refer to the wiki page for general scenarios of VT-d 1144 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1145 1146ERST 1147 1148DEF("name", HAS_ARG, QEMU_OPTION_name, 1149 "-name string1[,process=string2][,debug-threads=on|off]\n" 1150 " set the name of the guest\n" 1151 " string1 sets the window title and string2 the process name\n" 1152 " When debug-threads is enabled, individual threads are given a separate name\n" 1153 " NOTE: The thread names are for debugging and not a stable API.\n", 1154 QEMU_ARCH_ALL) 1155SRST 1156``-name name`` 1157 Sets the name of the guest. This name will be displayed in the SDL 1158 window caption. The name will also be used for the VNC server. Also 1159 optionally set the top visible process name in Linux. Naming of 1160 individual threads can also be enabled on Linux to aid debugging. 1161ERST 1162 1163DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1164 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1165 " specify machine UUID\n", QEMU_ARCH_ALL) 1166SRST 1167``-uuid uuid`` 1168 Set system UUID. 1169ERST 1170 1171DEFHEADING() 1172 1173DEFHEADING(Block device options:) 1174 1175SRST 1176The QEMU block device handling options have a long history and 1177have gone through several iterations as the feature set and complexity 1178of the block layer have grown. Many online guides to QEMU often 1179reference older and deprecated options, which can lead to confusion. 1180 1181The most explicit way to describe disks is to use a combination of 1182``-device`` to specify the hardware device and ``-blockdev`` to 1183describe the backend. The device defines what the guest sees and the 1184backend describes how QEMU handles the data. It is the only guaranteed 1185stable interface for describing block devices and as such is 1186recommended for management tools and scripting. 1187 1188The ``-drive`` option combines the device and backend into a single 1189command line option which is a more human friendly. There is however no 1190interface stability guarantee although some older board models still 1191need updating to work with the modern blockdev forms. 1192 1193Older options like ``-hda`` are essentially macros which expand into 1194``-drive`` options for various drive interfaces. The original forms 1195bake in a lot of assumptions from the days when QEMU was emulating a 1196legacy PC, they are not recommended for modern configurations. 1197 1198ERST 1199 1200DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1201 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1202DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1203SRST 1204``-fda file`` 1205 \ 1206``-fdb file`` 1207 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1208 the System Emulation Users Guide). 1209ERST 1210 1211DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1212 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1213DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1214DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1215 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1216DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1217SRST 1218``-hda file`` 1219 \ 1220``-hdb file`` 1221 \ 1222``-hdc file`` 1223 \ 1224``-hdd file`` 1225 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1226 chapter in the System Emulation Users Guide). 1227ERST 1228 1229DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1230 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1231 QEMU_ARCH_ALL) 1232SRST 1233``-cdrom file`` 1234 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1235 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1236 as filename. 1237ERST 1238 1239DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1240 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1241 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1242 " [,read-only=on|off][,auto-read-only=on|off]\n" 1243 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1244 " [,driver specific parameters...]\n" 1245 " configure a block backend\n", QEMU_ARCH_ALL) 1246SRST 1247``-blockdev option[,option[,option[,...]]]`` 1248 Define a new block driver node. Some of the options apply to all 1249 block drivers, other options are only accepted for a specific block 1250 driver. See below for a list of generic options and options for the 1251 most common block drivers. 1252 1253 Options that expect a reference to another node (e.g. ``file``) can 1254 be given in two ways. Either you specify the node name of an already 1255 existing node (file=node-name), or you define a new node inline, 1256 adding options for the referenced node after a dot 1257 (file.filename=path,file.aio=native). 1258 1259 A block driver node created with ``-blockdev`` can be used for a 1260 guest device by specifying its node name for the ``drive`` property 1261 in a ``-device`` argument that defines a block device. 1262 1263 ``Valid options for any block driver node:`` 1264 ``driver`` 1265 Specifies the block driver to use for the given node. 1266 1267 ``node-name`` 1268 This defines the name of the block driver node by which it 1269 will be referenced later. The name must be unique, i.e. it 1270 must not match the name of a different block driver node, or 1271 (if you use ``-drive`` as well) the ID of a drive. 1272 1273 If no node name is specified, it is automatically generated. 1274 The generated node name is not intended to be predictable 1275 and changes between QEMU invocations. For the top level, an 1276 explicit node name must be specified. 1277 1278 ``read-only`` 1279 Open the node read-only. Guest write attempts will fail. 1280 1281 Note that some block drivers support only read-only access, 1282 either generally or in certain configurations. In this case, 1283 the default value ``read-only=off`` does not work and the 1284 option must be specified explicitly. 1285 1286 ``auto-read-only`` 1287 If ``auto-read-only=on`` is set, QEMU may fall back to 1288 read-only usage even when ``read-only=off`` is requested, or 1289 even switch between modes as needed, e.g. depending on 1290 whether the image file is writable or whether a writing user 1291 is attached to the node. 1292 1293 ``force-share`` 1294 Override the image locking system of QEMU by forcing the 1295 node to utilize weaker shared access for permissions where 1296 it would normally request exclusive access. When there is 1297 the potential for multiple instances to have the same file 1298 open (whether this invocation of QEMU is the first or the 1299 second instance), both instances must permit shared access 1300 for the second instance to succeed at opening the file. 1301 1302 Enabling ``force-share=on`` requires ``read-only=on``. 1303 1304 ``cache.direct`` 1305 The host page cache can be avoided with ``cache.direct=on``. 1306 This will attempt to do disk IO directly to the guest's 1307 memory. QEMU may still perform an internal copy of the data. 1308 1309 ``cache.no-flush`` 1310 In case you don't care about data integrity over host 1311 failures, you can use ``cache.no-flush=on``. This option 1312 tells QEMU that it never needs to write any data to the disk 1313 but can instead keep things in cache. If anything goes 1314 wrong, like your host losing power, the disk storage getting 1315 disconnected accidentally, etc. your image will most 1316 probably be rendered unusable. 1317 1318 ``discard=discard`` 1319 discard is one of "ignore" (or "off") or "unmap" (or "on") 1320 and controls whether ``discard`` (also known as ``trim`` or 1321 ``unmap``) requests are ignored or passed to the filesystem. 1322 Some machine types may not support discard requests. 1323 1324 ``detect-zeroes=detect-zeroes`` 1325 detect-zeroes is "off", "on" or "unmap" and enables the 1326 automatic conversion of plain zero writes by the OS to 1327 driver specific optimized zero write commands. You may even 1328 choose "unmap" if discard is set to "unmap" to allow a zero 1329 write to be converted to an ``unmap`` operation. 1330 1331 ``Driver-specific options for file`` 1332 This is the protocol-level block driver for accessing regular 1333 files. 1334 1335 ``filename`` 1336 The path to the image file in the local filesystem 1337 1338 ``aio`` 1339 Specifies the AIO backend (threads/native/io_uring, 1340 default: threads) 1341 1342 ``locking`` 1343 Specifies whether the image file is protected with Linux OFD 1344 / POSIX locks. The default is to use the Linux Open File 1345 Descriptor API if available, otherwise no lock is applied. 1346 (auto/on/off, default: auto) 1347 1348 Example: 1349 1350 :: 1351 1352 -blockdev driver=file,node-name=disk,filename=disk.img 1353 1354 ``Driver-specific options for raw`` 1355 This is the image format block driver for raw images. It is 1356 usually stacked on top of a protocol level block driver such as 1357 ``file``. 1358 1359 ``file`` 1360 Reference to or definition of the data source block driver 1361 node (e.g. a ``file`` driver node) 1362 1363 Example 1: 1364 1365 :: 1366 1367 -blockdev driver=file,node-name=disk_file,filename=disk.img 1368 -blockdev driver=raw,node-name=disk,file=disk_file 1369 1370 Example 2: 1371 1372 :: 1373 1374 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1375 1376 ``Driver-specific options for qcow2`` 1377 This is the image format block driver for qcow2 images. It is 1378 usually stacked on top of a protocol level block driver such as 1379 ``file``. 1380 1381 ``file`` 1382 Reference to or definition of the data source block driver 1383 node (e.g. a ``file`` driver node) 1384 1385 ``backing`` 1386 Reference to or definition of the backing file block device 1387 (default is taken from the image file). It is allowed to 1388 pass ``null`` here in order to disable the default backing 1389 file. 1390 1391 ``lazy-refcounts`` 1392 Whether to enable the lazy refcounts feature (on/off; 1393 default is taken from the image file) 1394 1395 ``cache-size`` 1396 The maximum total size of the L2 table and refcount block 1397 caches in bytes (default: the sum of l2-cache-size and 1398 refcount-cache-size) 1399 1400 ``l2-cache-size`` 1401 The maximum size of the L2 table cache in bytes (default: if 1402 cache-size is not specified - 32M on Linux platforms, and 8M 1403 on non-Linux platforms; otherwise, as large as possible 1404 within the cache-size, while permitting the requested or the 1405 minimal refcount cache size) 1406 1407 ``refcount-cache-size`` 1408 The maximum size of the refcount block cache in bytes 1409 (default: 4 times the cluster size; or if cache-size is 1410 specified, the part of it which is not used for the L2 1411 cache) 1412 1413 ``cache-clean-interval`` 1414 Clean unused entries in the L2 and refcount caches. The 1415 interval is in seconds. The default value is 600 on 1416 supporting platforms, and 0 on other platforms. Setting it 1417 to 0 disables this feature. 1418 1419 ``pass-discard-request`` 1420 Whether discard requests to the qcow2 device should be 1421 forwarded to the data source (on/off; default: on if 1422 discard=unmap is specified, off otherwise) 1423 1424 ``pass-discard-snapshot`` 1425 Whether discard requests for the data source should be 1426 issued when a snapshot operation (e.g. deleting a snapshot) 1427 frees clusters in the qcow2 file (on/off; default: on) 1428 1429 ``pass-discard-other`` 1430 Whether discard requests for the data source should be 1431 issued on other occasions where a cluster gets freed 1432 (on/off; default: off) 1433 1434 ``overlap-check`` 1435 Which overlap checks to perform for writes to the image 1436 (none/constant/cached/all; default: cached). For details or 1437 finer granularity control refer to the QAPI documentation of 1438 ``blockdev-add``. 1439 1440 Example 1: 1441 1442 :: 1443 1444 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1445 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1446 1447 Example 2: 1448 1449 :: 1450 1451 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1452 1453 ``Driver-specific options for other drivers`` 1454 Please refer to the QAPI documentation of the ``blockdev-add`` 1455 QMP command. 1456ERST 1457 1458DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1459 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1460 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1461 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1462 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1463 " [,aio=threads|native|io_uring]\n" 1464 " [,readonly=on|off][,copy-on-read=on|off]\n" 1465 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1466 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1467 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1468 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1469 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1470 " [[,iops_size=is]]\n" 1471 " [[,group=g]]\n" 1472 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1473SRST 1474``-drive option[,option[,option[,...]]]`` 1475 Define a new drive. This includes creating a block driver node (the 1476 backend) as well as a guest device, and is mostly a shortcut for 1477 defining the corresponding ``-blockdev`` and ``-device`` options. 1478 1479 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1480 In addition, it knows the following options: 1481 1482 ``file=file`` 1483 This option defines which disk image (see the :ref:`disk images` 1484 chapter in the System Emulation Users Guide) to use with this drive. 1485 If the filename contains comma, you must double it (for instance, 1486 "file=my,,file" to use file "my,file"). 1487 1488 Special files such as iSCSI devices can be specified using 1489 protocol specific URLs. See the section for "Device URL Syntax" 1490 for more information. 1491 1492 ``if=interface`` 1493 This option defines on which type on interface the drive is 1494 connected. Available types are: ide, scsi, sd, mtd, floppy, 1495 pflash, virtio, none. 1496 1497 ``bus=bus,unit=unit`` 1498 These options define where is connected the drive by defining 1499 the bus number and the unit id. 1500 1501 ``index=index`` 1502 This option defines where the drive is connected by using an 1503 index in the list of available connectors of a given interface 1504 type. 1505 1506 ``media=media`` 1507 This option defines the type of the media: disk or cdrom. 1508 1509 ``snapshot=snapshot`` 1510 snapshot is "on" or "off" and controls snapshot mode for the 1511 given drive (see ``-snapshot``). 1512 1513 ``cache=cache`` 1514 cache is "none", "writeback", "unsafe", "directsync" or 1515 "writethrough" and controls how the host cache is used to access 1516 block data. This is a shortcut that sets the ``cache.direct`` 1517 and ``cache.no-flush`` options (as in ``-blockdev``), and 1518 additionally ``cache.writeback``, which provides a default for 1519 the ``write-cache`` option of block guest devices (as in 1520 ``-device``). The modes correspond to the following settings: 1521 1522 ============= =============== ============ ============== 1523 \ cache.writeback cache.direct cache.no-flush 1524 ============= =============== ============ ============== 1525 writeback on off off 1526 none on on off 1527 writethrough off off off 1528 directsync off on off 1529 unsafe on off on 1530 ============= =============== ============ ============== 1531 1532 The default mode is ``cache=writeback``. 1533 1534 ``aio=aio`` 1535 aio is "threads", "native", or "io_uring" and selects between pthread 1536 based disk I/O, native Linux AIO, or Linux io_uring API. 1537 1538 ``format=format`` 1539 Specify which disk format will be used rather than detecting the 1540 format. Can be used to specify format=raw to avoid interpreting 1541 an untrusted format header. 1542 1543 ``werror=action,rerror=action`` 1544 Specify which action to take on write and read errors. Valid 1545 actions are: "ignore" (ignore the error and try to continue), 1546 "stop" (pause QEMU), "report" (report the error to the guest), 1547 "enospc" (pause QEMU only if the host disk is full; report the 1548 error to the guest otherwise). The default setting is 1549 ``werror=enospc`` and ``rerror=report``. 1550 1551 ``copy-on-read=copy-on-read`` 1552 copy-on-read is "on" or "off" and enables whether to copy read 1553 backing file sectors into the image file. 1554 1555 ``bps=b,bps_rd=r,bps_wr=w`` 1556 Specify bandwidth throttling limits in bytes per second, either 1557 for all request types or for reads or writes only. Small values 1558 can lead to timeouts or hangs inside the guest. A safe minimum 1559 for disks is 2 MB/s. 1560 1561 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1562 Specify bursts in bytes per second, either for all request types 1563 or for reads or writes only. Bursts allow the guest I/O to spike 1564 above the limit temporarily. 1565 1566 ``iops=i,iops_rd=r,iops_wr=w`` 1567 Specify request rate limits in requests per second, either for 1568 all request types or for reads or writes only. 1569 1570 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1571 Specify bursts in requests per second, either for all request 1572 types or for reads or writes only. Bursts allow the guest I/O to 1573 spike above the limit temporarily. 1574 1575 ``iops_size=is`` 1576 Let every is bytes of a request count as a new request for iops 1577 throttling purposes. Use this option to prevent guests from 1578 circumventing iops limits by sending fewer but larger requests. 1579 1580 ``group=g`` 1581 Join a throttling quota group with given name g. All drives that 1582 are members of the same group are accounted for together. Use 1583 this option to prevent guests from circumventing throttling 1584 limits by using many small disks instead of a single larger 1585 disk. 1586 1587 By default, the ``cache.writeback=on`` mode is used. It will report 1588 data writes as completed as soon as the data is present in the host 1589 page cache. This is safe as long as your guest OS makes sure to 1590 correctly flush disk caches where needed. If your guest OS does not 1591 handle volatile disk write caches correctly and your host crashes or 1592 loses power, then the guest may experience data corruption. 1593 1594 For such guests, you should consider using ``cache.writeback=off``. 1595 This means that the host page cache will be used to read and write 1596 data, but write notification will be sent to the guest only after 1597 QEMU has made sure to flush each write to the disk. Be aware that 1598 this has a major impact on performance. 1599 1600 When using the ``-snapshot`` option, unsafe caching is always used. 1601 1602 Copy-on-read avoids accessing the same backing file sectors 1603 repeatedly and is useful when the backing file is over a slow 1604 network. By default copy-on-read is off. 1605 1606 Instead of ``-cdrom`` you can use: 1607 1608 .. parsed-literal:: 1609 1610 |qemu_system| -drive file=file,index=2,media=cdrom 1611 1612 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1613 1614 .. parsed-literal:: 1615 1616 |qemu_system| -drive file=file,index=0,media=disk 1617 |qemu_system| -drive file=file,index=1,media=disk 1618 |qemu_system| -drive file=file,index=2,media=disk 1619 |qemu_system| -drive file=file,index=3,media=disk 1620 1621 You can open an image using pre-opened file descriptors from an fd 1622 set: 1623 1624 .. parsed-literal:: 1625 1626 |qemu_system| \\ 1627 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1628 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1629 -drive file=/dev/fdset/2,index=0,media=disk 1630 1631 You can connect a CDROM to the slave of ide0: 1632 1633 .. parsed-literal:: 1634 1635 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1636 1637 If you don't specify the "file=" argument, you define an empty 1638 drive: 1639 1640 .. parsed-literal:: 1641 1642 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1643 1644 Instead of ``-fda``, ``-fdb``, you can use: 1645 1646 .. parsed-literal:: 1647 1648 |qemu_system_x86| -drive file=file,index=0,if=floppy 1649 |qemu_system_x86| -drive file=file,index=1,if=floppy 1650 1651 By default, interface is "ide" and index is automatically 1652 incremented: 1653 1654 .. parsed-literal:: 1655 1656 |qemu_system_x86| -drive file=a -drive file=b 1657 1658 is interpreted like: 1659 1660 .. parsed-literal:: 1661 1662 |qemu_system_x86| -hda a -hdb b 1663ERST 1664 1665DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1666 "-mtdblock file use 'file' as on-board Flash memory image\n", 1667 QEMU_ARCH_ALL) 1668SRST 1669``-mtdblock file`` 1670 Use file as on-board Flash memory image. 1671ERST 1672 1673DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1674 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1675SRST 1676``-sd file`` 1677 Use file as SecureDigital card image. 1678ERST 1679 1680DEF("snapshot", 0, QEMU_OPTION_snapshot, 1681 "-snapshot write to temporary files instead of disk image files\n", 1682 QEMU_ARCH_ALL) 1683SRST 1684``-snapshot`` 1685 Write to temporary files instead of disk image files. In this case, 1686 the raw disk image you use is not written back. You can however 1687 force the write back by pressing C-a s (see the :ref:`disk images` 1688 chapter in the System Emulation Users Guide). 1689 1690 .. warning:: 1691 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1692 to manually create snapshot images to attach to your blockdev). 1693 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1694 can use the 'snapshot' property on your drive declarations 1695 instead of this global option. 1696 1697ERST 1698 1699DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1700 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1701 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1702 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1703 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1704 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1705 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1706 " [[,throttling.iops-size=is]]\n" 1707 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1708 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1709 "-fsdev synth,id=id\n", 1710 QEMU_ARCH_ALL) 1711 1712SRST 1713``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1714 \ 1715``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1716 \ 1717``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1718 \ 1719``-fsdev synth,id=id[,readonly=on]`` 1720 Define a new file system device. Valid options are: 1721 1722 ``local`` 1723 Accesses to the filesystem are done by QEMU. 1724 1725 ``proxy`` 1726 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1727 1728 ``synth`` 1729 Synthetic filesystem, only used by QTests. 1730 1731 ``id=id`` 1732 Specifies identifier for this device. 1733 1734 ``path=path`` 1735 Specifies the export path for the file system device. Files 1736 under this path will be available to the 9p client on the guest. 1737 1738 ``security_model=security_model`` 1739 Specifies the security model to be used for this export path. 1740 Supported security models are "passthrough", "mapped-xattr", 1741 "mapped-file" and "none". In "passthrough" security model, files 1742 are stored using the same credentials as they are created on the 1743 guest. This requires QEMU to run as root. In "mapped-xattr" 1744 security model, some of the file attributes like uid, gid, mode 1745 bits and link target are stored as file attributes. For 1746 "mapped-file" these attributes are stored in the hidden 1747 .virtfs\_metadata directory. Directories exported by this 1748 security model cannot interact with other unix tools. "none" 1749 security model is same as passthrough except the sever won't 1750 report failures if it fails to set file attributes like 1751 ownership. Security model is mandatory only for local fsdriver. 1752 Other fsdrivers (like proxy) don't take security model as a 1753 parameter. 1754 1755 ``writeout=writeout`` 1756 This is an optional argument. The only supported value is 1757 "immediate". This means that host page cache will be used to 1758 read and write data but write notification will be sent to the 1759 guest only when the data has been reported as written by the 1760 storage subsystem. 1761 1762 ``readonly=on`` 1763 Enables exporting 9p share as a readonly mount for guests. By 1764 default read-write access is given. 1765 1766 ``socket=socket`` 1767 Enables proxy filesystem driver to use passed socket file for 1768 communicating with virtfs-proxy-helper(1). 1769 1770 ``sock_fd=sock_fd`` 1771 Enables proxy filesystem driver to use passed socket descriptor 1772 for communicating with virtfs-proxy-helper(1). Usually a helper 1773 like libvirt will create socketpair and pass one of the fds as 1774 sock\_fd. 1775 1776 ``fmode=fmode`` 1777 Specifies the default mode for newly created files on the host. 1778 Works only with security models "mapped-xattr" and 1779 "mapped-file". 1780 1781 ``dmode=dmode`` 1782 Specifies the default mode for newly created directories on the 1783 host. Works only with security models "mapped-xattr" and 1784 "mapped-file". 1785 1786 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1787 Specify bandwidth throttling limits in bytes per second, either 1788 for all request types or for reads or writes only. 1789 1790 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1791 Specify bursts in bytes per second, either for all request types 1792 or for reads or writes only. Bursts allow the guest I/O to spike 1793 above the limit temporarily. 1794 1795 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1796 Specify request rate limits in requests per second, either for 1797 all request types or for reads or writes only. 1798 1799 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1800 Specify bursts in requests per second, either for all request 1801 types or for reads or writes only. Bursts allow the guest I/O to 1802 spike above the limit temporarily. 1803 1804 ``throttling.iops-size=is`` 1805 Let every is bytes of a request count as a new request for iops 1806 throttling purposes. 1807 1808 -fsdev option is used along with -device driver "virtio-9p-...". 1809 1810``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1811 Options for virtio-9p-... driver are: 1812 1813 ``type`` 1814 Specifies the variant to be used. Supported values are "pci", 1815 "ccw" or "device", depending on the machine type. 1816 1817 ``fsdev=id`` 1818 Specifies the id value specified along with -fsdev option. 1819 1820 ``mount_tag=mount_tag`` 1821 Specifies the tag name to be used by the guest to mount this 1822 export point. 1823ERST 1824 1825DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1826 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1827 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1828 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1829 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1830 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1831 QEMU_ARCH_ALL) 1832 1833SRST 1834``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1835 \ 1836``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1837 \ 1838``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1839 \ 1840``-virtfs synth,mount_tag=mount_tag`` 1841 Define a new virtual filesystem device and expose it to the guest using 1842 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1843 directory on host is made directly accessible by guest as a pass-through 1844 file system by using the 9P network protocol for communication between 1845 host and guests, if desired even accessible, shared by several guests 1846 simultaneously. 1847 1848 Note that ``-virtfs`` is actually just a convenience shortcut for its 1849 generalized form ``-fsdev -device virtio-9p-pci``. 1850 1851 The general form of pass-through file system options are: 1852 1853 ``local`` 1854 Accesses to the filesystem are done by QEMU. 1855 1856 ``proxy`` 1857 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1858 1859 ``synth`` 1860 Synthetic filesystem, only used by QTests. 1861 1862 ``id=id`` 1863 Specifies identifier for the filesystem device 1864 1865 ``path=path`` 1866 Specifies the export path for the file system device. Files 1867 under this path will be available to the 9p client on the guest. 1868 1869 ``security_model=security_model`` 1870 Specifies the security model to be used for this export path. 1871 Supported security models are "passthrough", "mapped-xattr", 1872 "mapped-file" and "none". In "passthrough" security model, files 1873 are stored using the same credentials as they are created on the 1874 guest. This requires QEMU to run as root. In "mapped-xattr" 1875 security model, some of the file attributes like uid, gid, mode 1876 bits and link target are stored as file attributes. For 1877 "mapped-file" these attributes are stored in the hidden 1878 .virtfs\_metadata directory. Directories exported by this 1879 security model cannot interact with other unix tools. "none" 1880 security model is same as passthrough except the sever won't 1881 report failures if it fails to set file attributes like 1882 ownership. Security model is mandatory only for local fsdriver. 1883 Other fsdrivers (like proxy) don't take security model as a 1884 parameter. 1885 1886 ``writeout=writeout`` 1887 This is an optional argument. The only supported value is 1888 "immediate". This means that host page cache will be used to 1889 read and write data but write notification will be sent to the 1890 guest only when the data has been reported as written by the 1891 storage subsystem. 1892 1893 ``readonly=on`` 1894 Enables exporting 9p share as a readonly mount for guests. By 1895 default read-write access is given. 1896 1897 ``socket=socket`` 1898 Enables proxy filesystem driver to use passed socket file for 1899 communicating with virtfs-proxy-helper(1). Usually a helper like 1900 libvirt will create socketpair and pass one of the fds as 1901 sock\_fd. 1902 1903 ``sock_fd`` 1904 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1905 socket descriptor for interfacing with virtfs-proxy-helper(1). 1906 1907 ``fmode=fmode`` 1908 Specifies the default mode for newly created files on the host. 1909 Works only with security models "mapped-xattr" and 1910 "mapped-file". 1911 1912 ``dmode=dmode`` 1913 Specifies the default mode for newly created directories on the 1914 host. Works only with security models "mapped-xattr" and 1915 "mapped-file". 1916 1917 ``mount_tag=mount_tag`` 1918 Specifies the tag name to be used by the guest to mount this 1919 export point. 1920 1921 ``multidevs=multidevs`` 1922 Specifies how to deal with multiple devices being shared with a 1923 9p export. Supported behaviours are either "remap", "forbid" or 1924 "warn". The latter is the default behaviour on which virtfs 9p 1925 expects only one device to be shared with the same export, and 1926 if more than one device is shared and accessed via the same 9p 1927 export then only a warning message is logged (once) by qemu on 1928 host side. In order to avoid file ID collisions on guest you 1929 should either create a separate virtfs export for each device to 1930 be shared with guests (recommended way) or you might use "remap" 1931 instead which allows you to share multiple devices with only one 1932 export instead, which is achieved by remapping the original 1933 inode numbers from host to guest in a way that would prevent 1934 such collisions. Remapping inodes in such use cases is required 1935 because the original device IDs from host are never passed and 1936 exposed on guest. Instead all files of an export shared with 1937 virtfs always share the same device id on guest. So two files 1938 with identical inode numbers but from actually different devices 1939 on host would otherwise cause a file ID collision and hence 1940 potential misbehaviours on guest. "forbid" on the other hand 1941 assumes like "warn" that only one device is shared by the same 1942 export, however it will not only log a warning message but also 1943 deny access to additional devices on guest. Note though that 1944 "forbid" does currently not block all possible file access 1945 operations (e.g. readdir() would still return entries from other 1946 devices). 1947ERST 1948 1949DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1950 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1951 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1952 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1953 " [,timeout=timeout]\n" 1954 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1955 1956SRST 1957``-iscsi`` 1958 Configure iSCSI session parameters. 1959ERST 1960 1961DEFHEADING() 1962 1963DEFHEADING(USB convenience options:) 1964 1965DEF("usb", 0, QEMU_OPTION_usb, 1966 "-usb enable on-board USB host controller (if not enabled by default)\n", 1967 QEMU_ARCH_ALL) 1968SRST 1969``-usb`` 1970 Enable USB emulation on machine types with an on-board USB host 1971 controller (if not enabled by default). Note that on-board USB host 1972 controllers may not support USB 3.0. In this case 1973 ``-device qemu-xhci`` can be used instead on machines with PCI. 1974ERST 1975 1976DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1977 "-usbdevice name add the host or guest USB device 'name'\n", 1978 QEMU_ARCH_ALL) 1979SRST 1980``-usbdevice devname`` 1981 Add the USB device devname, and enable an on-board USB controller 1982 if possible and necessary (just like it can be done via 1983 ``-machine usb=on``). Note that this option is mainly intended for 1984 the user's convenience only. More fine-grained control can be 1985 achieved by selecting a USB host controller (if necessary) and the 1986 desired USB device via the ``-device`` option instead. For example, 1987 instead of using ``-usbdevice mouse`` it is possible to use 1988 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1989 to a USB 3.0 controller instead (at least on machines that support 1990 PCI and do not have an USB controller enabled by default yet). 1991 For more details, see the chapter about 1992 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1993 Possible devices for devname are: 1994 1995 ``braille`` 1996 Braille device. This will use BrlAPI to display the braille 1997 output on a real or fake device (i.e. it also creates a 1998 corresponding ``braille`` chardev automatically beside the 1999 ``usb-braille`` USB device). 2000 2001 ``keyboard`` 2002 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2003 2004 ``mouse`` 2005 Virtual Mouse. This will override the PS/2 mouse emulation when 2006 activated. 2007 2008 ``tablet`` 2009 Pointer device that uses absolute coordinates (like a 2010 touchscreen). This means QEMU is able to report the mouse 2011 position without having to grab the mouse. Also overrides the 2012 PS/2 mouse emulation when activated. 2013 2014 ``wacom-tablet`` 2015 Wacom PenPartner USB tablet. 2016 2017 2018ERST 2019 2020DEFHEADING() 2021 2022DEFHEADING(Display options:) 2023 2024DEF("display", HAS_ARG, QEMU_OPTION_display, 2025#if defined(CONFIG_SPICE) 2026 "-display spice-app[,gl=on|off]\n" 2027#endif 2028#if defined(CONFIG_SDL) 2029 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2030 " [,window-close=on|off]\n" 2031#endif 2032#if defined(CONFIG_GTK) 2033 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2034 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2035 " [,show-menubar=on|off]\n" 2036#endif 2037#if defined(CONFIG_VNC) 2038 "-display vnc=<display>[,<optargs>]\n" 2039#endif 2040#if defined(CONFIG_CURSES) 2041 "-display curses[,charset=<encoding>]\n" 2042#endif 2043#if defined(CONFIG_COCOA) 2044 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2045#endif 2046#if defined(CONFIG_OPENGL) 2047 "-display egl-headless[,rendernode=<file>]\n" 2048#endif 2049#if defined(CONFIG_DBUS_DISPLAY) 2050 "-display dbus[,addr=<dbusaddr>]\n" 2051 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2052#endif 2053#if defined(CONFIG_COCOA) 2054 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 2055#endif 2056 "-display none\n" 2057 " select display backend type\n" 2058 " The default display is equivalent to\n " 2059#if defined(CONFIG_GTK) 2060 "\"-display gtk\"\n" 2061#elif defined(CONFIG_SDL) 2062 "\"-display sdl\"\n" 2063#elif defined(CONFIG_COCOA) 2064 "\"-display cocoa\"\n" 2065#elif defined(CONFIG_VNC) 2066 "\"-vnc localhost:0,to=99,id=default\"\n" 2067#else 2068 "\"-display none\"\n" 2069#endif 2070 , QEMU_ARCH_ALL) 2071SRST 2072``-display type`` 2073 Select type of display to use. Use ``-display help`` to list the available 2074 display types. Valid values for type are 2075 2076 ``spice-app[,gl=on|off]`` 2077 Start QEMU as a Spice server and launch the default Spice client 2078 application. The Spice server will redirect the serial consoles 2079 and QEMU monitors. (Since 4.0) 2080 2081 ``dbus`` 2082 Export the display over D-Bus interfaces. (Since 7.0) 2083 2084 The connection is registered with the "org.qemu" name (and queued when 2085 already owned). 2086 2087 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2088 2089 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2090 2091 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2092 will share framebuffers with DMABUF file descriptors). 2093 2094 ``sdl`` 2095 Display video output via SDL (usually in a separate graphics 2096 window; see the SDL documentation for other possibilities). 2097 Valid parameters are: 2098 2099 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2100 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2101 either ``lshift-lctrl-lalt`` or ``rctrl``. 2102 2103 ``gl=on|off|core|es`` : Use OpenGL for displaying 2104 2105 ``show-cursor=on|off`` : Force showing the mouse cursor 2106 2107 ``window-close=on|off`` : Allow to quit qemu with window close button 2108 2109 ``gtk`` 2110 Display video output in a GTK window. This interface provides 2111 drop-down menus and other UI elements to configure and control 2112 the VM during runtime. Valid parameters are: 2113 2114 ``full-screen=on|off`` : Start in fullscreen mode 2115 2116 ``gl=on|off`` : Use OpenGL for displaying 2117 2118 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2119 2120 ``show-tabs=on|off`` : Display the tab bar for switching between the 2121 various graphical interfaces (e.g. VGA and 2122 virtual console character devices) by default. 2123 2124 ``show-cursor=on|off`` : Force showing the mouse cursor 2125 2126 ``window-close=on|off`` : Allow to quit qemu with window close button 2127 2128 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2129 2130 ``curses[,charset=<encoding>]`` 2131 Display video output via curses. For graphics device models 2132 which support a text mode, QEMU can display this output using a 2133 curses/ncurses interface. Nothing is displayed when the graphics 2134 device is in graphical mode or if the graphics device does not 2135 support a text mode. Generally only the VGA device models 2136 support text mode. The font charset used by the guest can be 2137 specified with the ``charset`` option, for example 2138 ``charset=CP850`` for IBM CP850 encoding. The default is 2139 ``CP437``. 2140 2141 ``cocoa`` 2142 Display video output in a Cocoa window. Mac only. This interface 2143 provides drop-down menus and other UI elements to configure and 2144 control the VM during runtime. Valid parameters are: 2145 2146 ``show-cursor=on|off`` : Force showing the mouse cursor 2147 2148 ``left-command-key=on|off`` : Disable forwarding left command key to host 2149 2150 ``egl-headless[,rendernode=<file>]`` 2151 Offload all OpenGL operations to a local DRI device. For any 2152 graphical display, this display needs to be paired with either 2153 VNC or SPICE displays. 2154 2155 ``vnc=<display>`` 2156 Start a VNC server on display <display> 2157 2158 ``none`` 2159 Do not display video output. The guest will still see an 2160 emulated graphics card, but its output will not be displayed to 2161 the QEMU user. This option differs from the -nographic option in 2162 that it only affects what is done with video output; -nographic 2163 also changes the destination of the serial and parallel port 2164 data. 2165ERST 2166 2167DEF("nographic", 0, QEMU_OPTION_nographic, 2168 "-nographic disable graphical output and redirect serial I/Os to console\n", 2169 QEMU_ARCH_ALL) 2170SRST 2171``-nographic`` 2172 Normally, if QEMU is compiled with graphical window support, it 2173 displays output such as guest graphics, guest console, and the QEMU 2174 monitor in a window. With this option, you can totally disable 2175 graphical output so that QEMU is a simple command line application. 2176 The emulated serial port is redirected on the console and muxed with 2177 the monitor (unless redirected elsewhere explicitly). Therefore, you 2178 can still use QEMU to debug a Linux kernel with a serial console. 2179 Use C-a h for help on switching between the console and monitor. 2180ERST 2181 2182#ifdef CONFIG_SPICE 2183DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2184 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2185 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2186 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2187 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2188 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2189 " [,tls-ciphers=<list>]\n" 2190 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2191 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2192 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2193 " [,password-secret=<secret-id>]\n" 2194 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2195 " [,jpeg-wan-compression=[auto|never|always]]\n" 2196 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2197 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2198 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2199 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2200 " [,gl=[on|off]][,rendernode=<file>]\n" 2201 " enable spice\n" 2202 " at least one of {port, tls-port} is mandatory\n", 2203 QEMU_ARCH_ALL) 2204#endif 2205SRST 2206``-spice option[,option[,...]]`` 2207 Enable the spice remote desktop protocol. Valid options are 2208 2209 ``port=<nr>`` 2210 Set the TCP port spice is listening on for plaintext channels. 2211 2212 ``addr=<addr>`` 2213 Set the IP address spice is listening on. Default is any 2214 address. 2215 2216 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2217 Force using the specified IP version. 2218 2219 ``password-secret=<secret-id>`` 2220 Set the ID of the ``secret`` object containing the password 2221 you need to authenticate. 2222 2223 ``sasl=on|off`` 2224 Require that the client use SASL to authenticate with the spice. 2225 The exact choice of authentication method used is controlled 2226 from the system / user's SASL configuration file for the 'qemu' 2227 service. This is typically found in /etc/sasl2/qemu.conf. If 2228 running QEMU as an unprivileged user, an environment variable 2229 SASL\_CONF\_PATH can be used to make it search alternate 2230 locations for the service config. While some SASL auth methods 2231 can also provide data encryption (eg GSSAPI), it is recommended 2232 that SASL always be combined with the 'tls' and 'x509' settings 2233 to enable use of SSL and server certificates. This ensures a 2234 data encryption preventing compromise of authentication 2235 credentials. 2236 2237 ``disable-ticketing=on|off`` 2238 Allow client connects without authentication. 2239 2240 ``disable-copy-paste=on|off`` 2241 Disable copy paste between the client and the guest. 2242 2243 ``disable-agent-file-xfer=on|off`` 2244 Disable spice-vdagent based file-xfer between the client and the 2245 guest. 2246 2247 ``tls-port=<nr>`` 2248 Set the TCP port spice is listening on for encrypted channels. 2249 2250 ``x509-dir=<dir>`` 2251 Set the x509 file directory. Expects same filenames as -vnc 2252 $display,x509=$dir 2253 2254 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2255 The x509 file names can also be configured individually. 2256 2257 ``tls-ciphers=<list>`` 2258 Specify which ciphers to use. 2259 2260 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2261 Force specific channel to be used with or without TLS 2262 encryption. The options can be specified multiple times to 2263 configure multiple channels. The special name "default" can be 2264 used to set the default mode. For channels which are not 2265 explicitly forced into one mode the spice client is allowed to 2266 pick tls/plaintext as he pleases. 2267 2268 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2269 Configure image compression (lossless). Default is auto\_glz. 2270 2271 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2272 Configure wan image compression (lossy for slow links). Default 2273 is auto. 2274 2275 ``streaming-video=[off|all|filter]`` 2276 Configure video stream detection. Default is off. 2277 2278 ``agent-mouse=[on|off]`` 2279 Enable/disable passing mouse events via vdagent. Default is on. 2280 2281 ``playback-compression=[on|off]`` 2282 Enable/disable audio stream compression (using celt 0.5.1). 2283 Default is on. 2284 2285 ``seamless-migration=[on|off]`` 2286 Enable/disable spice seamless migration. Default is off. 2287 2288 ``gl=[on|off]`` 2289 Enable/disable OpenGL context. Default is off. 2290 2291 ``rendernode=<file>`` 2292 DRM render node for OpenGL rendering. If not specified, it will 2293 pick the first available. (Since 2.9) 2294ERST 2295 2296DEF("portrait", 0, QEMU_OPTION_portrait, 2297 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2298 QEMU_ARCH_ALL) 2299SRST 2300``-portrait`` 2301 Rotate graphical output 90 deg left (only PXA LCD). 2302ERST 2303 2304DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2305 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2306 QEMU_ARCH_ALL) 2307SRST 2308``-rotate deg`` 2309 Rotate graphical output some deg left (only PXA LCD). 2310ERST 2311 2312DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2313 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2314 " select video card type\n", QEMU_ARCH_ALL) 2315SRST 2316``-vga type`` 2317 Select type of VGA card to emulate. Valid values for type are 2318 2319 ``cirrus`` 2320 Cirrus Logic GD5446 Video card. All Windows versions starting 2321 from Windows 95 should recognize and use this graphic card. For 2322 optimal performances, use 16 bit color depth in the guest and 2323 the host OS. (This card was the default before QEMU 2.2) 2324 2325 ``std`` 2326 Standard VGA card with Bochs VBE extensions. If your guest OS 2327 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2328 you want to use high resolution modes (>= 1280x1024x16) then you 2329 should use this option. (This card is the default since QEMU 2330 2.2) 2331 2332 ``vmware`` 2333 VMWare SVGA-II compatible adapter. Use it if you have 2334 sufficiently recent XFree86/XOrg server or Windows guest with a 2335 driver for this card. 2336 2337 ``qxl`` 2338 QXL paravirtual graphic card. It is VGA compatible (including 2339 VESA 2.0 VBE support). Works best with qxl guest drivers 2340 installed though. Recommended choice when using the spice 2341 protocol. 2342 2343 ``tcx`` 2344 (sun4m only) Sun TCX framebuffer. This is the default 2345 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2346 colour depths at a fixed resolution of 1024x768. 2347 2348 ``cg3`` 2349 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2350 framebuffer for sun4m machines available in both 1024x768 2351 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2352 wishing to run older Solaris versions. 2353 2354 ``virtio`` 2355 Virtio VGA card. 2356 2357 ``none`` 2358 Disable VGA card. 2359ERST 2360 2361DEF("full-screen", 0, QEMU_OPTION_full_screen, 2362 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2363SRST 2364``-full-screen`` 2365 Start in full screen. 2366ERST 2367 2368DEF("g", HAS_ARG, QEMU_OPTION_g , 2369 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2370 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2371SRST 2372``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2373 Set the initial graphical resolution and depth (PPC, SPARC only). 2374 2375 For PPC the default is 800x600x32. 2376 2377 For SPARC with the TCX graphics device, the default is 1024x768x8 2378 with the option of 1024x768x24. For cgthree, the default is 2379 1024x768x8 with the option of 1152x900x8 for people who wish to use 2380 OBP. 2381ERST 2382 2383DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2384 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2385SRST 2386``-vnc display[,option[,option[,...]]]`` 2387 Normally, if QEMU is compiled with graphical window support, it 2388 displays output such as guest graphics, guest console, and the QEMU 2389 monitor in a window. With this option, you can have QEMU listen on 2390 VNC display display and redirect the VGA display over the VNC 2391 session. It is very useful to enable the usb tablet device when 2392 using this option (option ``-device usb-tablet``). When using the 2393 VNC display, you must use the ``-k`` parameter to set the keyboard 2394 layout if you are not using en-us. Valid syntax for the display is 2395 2396 ``to=L`` 2397 With this option, QEMU will try next available VNC displays, 2398 until the number L, if the origianlly defined "-vnc display" is 2399 not available, e.g. port 5900+display is already used by another 2400 application. By default, to=0. 2401 2402 ``host:d`` 2403 TCP connections will only be allowed from host on display d. By 2404 convention the TCP port is 5900+d. Optionally, host can be 2405 omitted in which case the server will accept connections from 2406 any host. 2407 2408 ``unix:path`` 2409 Connections will be allowed over UNIX domain sockets where path 2410 is the location of a unix socket to listen for connections on. 2411 2412 ``none`` 2413 VNC is initialized but not started. The monitor ``change`` 2414 command can be used to later start the VNC server. 2415 2416 Following the display value there may be one or more option flags 2417 separated by commas. Valid options are 2418 2419 ``reverse=on|off`` 2420 Connect to a listening VNC client via a "reverse" connection. 2421 The client is specified by the display. For reverse network 2422 connections (host:d,``reverse``), the d argument is a TCP port 2423 number, not a display number. 2424 2425 ``websocket=on|off`` 2426 Opens an additional TCP listening port dedicated to VNC 2427 Websocket connections. If a bare websocket option is given, the 2428 Websocket port is 5700+display. An alternative port can be 2429 specified with the syntax ``websocket``\ =port. 2430 2431 If host is specified connections will only be allowed from this 2432 host. It is possible to control the websocket listen address 2433 independently, using the syntax ``websocket``\ =host:port. 2434 2435 If no TLS credentials are provided, the websocket connection 2436 runs in unencrypted mode. If TLS credentials are provided, the 2437 websocket connection requires encrypted client connections. 2438 2439 ``password=on|off`` 2440 Require that password based authentication is used for client 2441 connections. 2442 2443 The password must be set separately using the ``set_password`` 2444 command in the :ref:`QEMU monitor`. The 2445 syntax to change your password is: 2446 ``set_password <protocol> <password>`` where <protocol> could be 2447 either "vnc" or "spice". 2448 2449 If you would like to change <protocol> password expiration, you 2450 should use ``expire_password <protocol> <expiration-time>`` 2451 where expiration time could be one of the following options: 2452 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2453 make password expire in 60 seconds, or 1335196800 to make 2454 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2455 this date and time). 2456 2457 You can also use keywords "now" or "never" for the expiration 2458 time to allow <protocol> password to expire immediately or never 2459 expire. 2460 2461 ``password-secret=<secret-id>`` 2462 Require that password based authentication is used for client 2463 connections, using the password provided by the ``secret`` 2464 object identified by ``secret-id``. 2465 2466 ``tls-creds=ID`` 2467 Provides the ID of a set of TLS credentials to use to secure the 2468 VNC server. They will apply to both the normal VNC server socket 2469 and the websocket socket (if enabled). Setting TLS credentials 2470 will cause the VNC server socket to enable the VeNCrypt auth 2471 mechanism. The credentials should have been previously created 2472 using the ``-object tls-creds`` argument. 2473 2474 ``tls-authz=ID`` 2475 Provides the ID of the QAuthZ authorization object against which 2476 the client's x509 distinguished name will validated. This object 2477 is only resolved at time of use, so can be deleted and recreated 2478 on the fly while the VNC server is active. If missing, it will 2479 default to denying access. 2480 2481 ``sasl=on|off`` 2482 Require that the client use SASL to authenticate with the VNC 2483 server. The exact choice of authentication method used is 2484 controlled from the system / user's SASL configuration file for 2485 the 'qemu' service. This is typically found in 2486 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2487 an environment variable SASL\_CONF\_PATH can be used to make it 2488 search alternate locations for the service config. While some 2489 SASL auth methods can also provide data encryption (eg GSSAPI), 2490 it is recommended that SASL always be combined with the 'tls' 2491 and 'x509' settings to enable use of SSL and server 2492 certificates. This ensures a data encryption preventing 2493 compromise of authentication credentials. See the 2494 :ref:`VNC security` section in the System Emulation Users Guide 2495 for details on using SASL authentication. 2496 2497 ``sasl-authz=ID`` 2498 Provides the ID of the QAuthZ authorization object against which 2499 the client's SASL username will validated. This object is only 2500 resolved at time of use, so can be deleted and recreated on the 2501 fly while the VNC server is active. If missing, it will default 2502 to denying access. 2503 2504 ``acl=on|off`` 2505 Legacy method for enabling authorization of clients against the 2506 x509 distinguished name and SASL username. It results in the 2507 creation of two ``authz-list`` objects with IDs of 2508 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2509 objects must be configured with the HMP ACL commands. 2510 2511 This option is deprecated and should no longer be used. The new 2512 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2513 2514 ``lossy=on|off`` 2515 Enable lossy compression methods (gradient, JPEG, ...). If this 2516 option is set, VNC client may receive lossy framebuffer updates 2517 depending on its encoding settings. Enabling this option can 2518 save a lot of bandwidth at the expense of quality. 2519 2520 ``non-adaptive=on|off`` 2521 Disable adaptive encodings. Adaptive encodings are enabled by 2522 default. An adaptive encoding will try to detect frequently 2523 updated screen regions, and send updates in these regions using 2524 a lossy encoding (like JPEG). This can be really helpful to save 2525 bandwidth when playing videos. Disabling adaptive encodings 2526 restores the original static behavior of encodings like Tight. 2527 2528 ``share=[allow-exclusive|force-shared|ignore]`` 2529 Set display sharing policy. 'allow-exclusive' allows clients to 2530 ask for exclusive access. As suggested by the rfb spec this is 2531 implemented by dropping other connections. Connecting multiple 2532 clients in parallel requires all clients asking for a shared 2533 session (vncviewer: -shared switch). This is the default. 2534 'force-shared' disables exclusive client access. Useful for 2535 shared desktop sessions, where you don't want someone forgetting 2536 specify -shared disconnect everybody else. 'ignore' completely 2537 ignores the shared flag and allows everybody connect 2538 unconditionally. Doesn't conform to the rfb spec but is 2539 traditional QEMU behavior. 2540 2541 ``key-delay-ms`` 2542 Set keyboard delay, for key down and key up events, in 2543 milliseconds. Default is 10. Keyboards are low-bandwidth 2544 devices, so this slowdown can help the device and guest to keep 2545 up and not lose events in case events are arriving in bulk. 2546 Possible causes for the latter are flaky network connections, or 2547 scripts for automated testing. 2548 2549 ``audiodev=audiodev`` 2550 Use the specified audiodev when the VNC client requests audio 2551 transmission. When not using an -audiodev argument, this option 2552 must be omitted, otherwise is must be present and specify a 2553 valid audiodev. 2554 2555 ``power-control=on|off`` 2556 Permit the remote client to issue shutdown, reboot or reset power 2557 control requests. 2558ERST 2559 2560ARCHHEADING(, QEMU_ARCH_I386) 2561 2562ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2563 2564DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2565 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2566 QEMU_ARCH_I386) 2567SRST 2568``-win2k-hack`` 2569 Use it when installing Windows 2000 to avoid a disk full bug. After 2570 Windows 2000 is installed, you no longer need this option (this 2571 option slows down the IDE transfers). 2572ERST 2573 2574DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2575 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2576 QEMU_ARCH_I386) 2577SRST 2578``-no-fd-bootchk`` 2579 Disable boot signature checking for floppy disks in BIOS. May be 2580 needed to boot from old floppy disks. 2581ERST 2582 2583DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2584 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2585SRST 2586``-no-acpi`` 2587 Disable ACPI (Advanced Configuration and Power Interface) support. 2588 Use it if your guest OS complains about ACPI problems (PC target 2589 machine only). 2590ERST 2591 2592DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2593 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2594SRST 2595``-no-hpet`` 2596 Disable HPET support. Deprecated, use '-machine hpet=off' instead. 2597ERST 2598 2599DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2600 "-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" 2601 " ACPI table description\n", QEMU_ARCH_I386) 2602SRST 2603``-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]...]`` 2604 Add ACPI table with specified header fields and context from 2605 specified files. For file=, take whole ACPI table from the specified 2606 files, including all ACPI headers (possible overridden by other 2607 options). For data=, only data portion of the table is used, all 2608 header information is specified in the command line. If a SLIC table 2609 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2610 fields will override the same in the RSDT and the FADT (a.k.a. 2611 FACP), in order to ensure the field matches required by the 2612 Microsoft SLIC spec and the ACPI spec. 2613ERST 2614 2615DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2616 "-smbios file=binary\n" 2617 " load SMBIOS entry from binary file\n" 2618 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2619 " [,uefi=on|off]\n" 2620 " specify SMBIOS type 0 fields\n" 2621 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2622 " [,uuid=uuid][,sku=str][,family=str]\n" 2623 " specify SMBIOS type 1 fields\n" 2624 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2625 " [,asset=str][,location=str]\n" 2626 " specify SMBIOS type 2 fields\n" 2627 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2628 " [,sku=str]\n" 2629 " specify SMBIOS type 3 fields\n" 2630 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2631 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2632 " [,processor-id=%d]\n" 2633 " specify SMBIOS type 4 fields\n" 2634 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2635 " specify SMBIOS type 8 fields\n" 2636 "-smbios type=11[,value=str][,path=filename]\n" 2637 " specify SMBIOS type 11 fields\n" 2638 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2639 " [,asset=str][,part=str][,speed=%d]\n" 2640 " specify SMBIOS type 17 fields\n" 2641 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2642 " specify SMBIOS type 41 fields\n", 2643 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2644SRST 2645``-smbios file=binary`` 2646 Load SMBIOS entry from binary file. 2647 2648``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2649 Specify SMBIOS type 0 fields 2650 2651``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2652 Specify SMBIOS type 1 fields 2653 2654``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2655 Specify SMBIOS type 2 fields 2656 2657``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2658 Specify SMBIOS type 3 fields 2659 2660``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2661 Specify SMBIOS type 4 fields 2662 2663``-smbios type=11[,value=str][,path=filename]`` 2664 Specify SMBIOS type 11 fields 2665 2666 This argument can be repeated multiple times, and values are added in the order they are parsed. 2667 Applications intending to use OEM strings data are encouraged to use their application name as 2668 a prefix for the value string. This facilitates passing information for multiple applications 2669 concurrently. 2670 2671 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2672 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2673 2674 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2675 the SMBIOS table in the order in which they appear. 2676 2677 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2678 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2679 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2680 data set, for example, by specifying the serial ID of a block device. 2681 2682 An example passing three strings is 2683 2684 .. parsed-literal:: 2685 2686 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2687 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2688 path=/some/file/with/oemstringsdata.txt 2689 2690 In the guest OS this is visible with the ``dmidecode`` command 2691 2692 .. parsed-literal:: 2693 2694 $ dmidecode -t 11 2695 Handle 0x0E00, DMI type 11, 5 bytes 2696 OEM Strings 2697 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2698 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2699 String 3: myapp:some extra data 2700 2701 2702``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2703 Specify SMBIOS type 17 fields 2704 2705``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2706 Specify SMBIOS type 41 fields 2707 2708 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2709 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2710 position on the PCI bus. 2711 2712 Here is an example of use: 2713 2714 .. parsed-literal:: 2715 2716 -netdev user,id=internet \\ 2717 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2718 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2719 2720 In the guest OS, the device should then appear as ``eno1``: 2721 2722 ..parsed-literal:: 2723 2724 $ ip -brief l 2725 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2726 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2727 2728 Currently, the PCI device has to be attached to the root bus. 2729 2730ERST 2731 2732DEFHEADING() 2733 2734DEFHEADING(Network options:) 2735 2736DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2737#ifdef CONFIG_SLIRP 2738 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2739 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2740 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2741 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2742 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2743#ifndef _WIN32 2744 "[,smb=dir[,smbserver=addr]]\n" 2745#endif 2746 " configure a user mode network backend with ID 'str',\n" 2747 " its DHCP server and optional services\n" 2748#endif 2749#ifdef _WIN32 2750 "-netdev tap,id=str,ifname=name\n" 2751 " configure a host TAP network backend with ID 'str'\n" 2752#else 2753 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2754 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2755 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2756 " [,poll-us=n]\n" 2757 " configure a host TAP network backend with ID 'str'\n" 2758 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2759 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2760 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2761 " to deconfigure it\n" 2762 " use '[down]script=no' to disable script execution\n" 2763 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2764 " configure it\n" 2765 " use 'fd=h' to connect to an already opened TAP interface\n" 2766 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2767 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2768 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2769 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2770 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2771 " use vhost=on to enable experimental in kernel accelerator\n" 2772 " (only has effect for virtio guests which use MSIX)\n" 2773 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2774 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2775 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2776 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2777 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2778 " spent on busy polling for vhost net\n" 2779 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2780 " configure a host TAP network backend with ID 'str' that is\n" 2781 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2782 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2783#endif 2784#ifdef __linux__ 2785 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2786 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2787 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2788 " [,rxcookie=rxcookie][,offset=offset]\n" 2789 " configure a network backend with ID 'str' connected to\n" 2790 " an Ethernet over L2TPv3 pseudowire.\n" 2791 " Linux kernel 3.3+ as well as most routers can talk\n" 2792 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2793 " VM to a router and even VM to Host. It is a nearly-universal\n" 2794 " standard (RFC3931). Note - this implementation uses static\n" 2795 " pre-configured tunnels (same as the Linux kernel).\n" 2796 " use 'src=' to specify source address\n" 2797 " use 'dst=' to specify destination address\n" 2798 " use 'udp=on' to specify udp encapsulation\n" 2799 " use 'srcport=' to specify source udp port\n" 2800 " use 'dstport=' to specify destination udp port\n" 2801 " use 'ipv6=on' to force v6\n" 2802 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2803 " well as a weak security measure\n" 2804 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2805 " use 'txcookie=0x012345678' to specify a txcookie\n" 2806 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2807 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2808 " use 'pincounter=on' to work around broken counter handling in peer\n" 2809 " use 'offset=X' to add an extra offset between header and data\n" 2810#endif 2811 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2812 " configure a network backend to connect to another network\n" 2813 " using a socket connection\n" 2814 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2815 " configure a network backend to connect to a multicast maddr and port\n" 2816 " use 'localaddr=addr' to specify the host address to send packets from\n" 2817 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2818 " configure a network backend to connect to another network\n" 2819 " using an UDP tunnel\n" 2820 "-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" 2821 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2822 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2823 " configure a network backend to connect to another network\n" 2824 " using a socket connection in stream mode.\n" 2825 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2826 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2827 " configure a network backend to connect to a multicast maddr and port\n" 2828 " use ``local.host=addr`` to specify the host address to send packets from\n" 2829 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2830 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2831 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2832 " configure a network backend to connect to another network\n" 2833 " using an UDP tunnel\n" 2834#ifdef CONFIG_VDE 2835 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2836 " configure a network backend to connect to port 'n' of a vde switch\n" 2837 " running on host and listening for incoming connections on 'socketpath'.\n" 2838 " Use group 'groupname' and mode 'octalmode' to change default\n" 2839 " ownership and permissions for communication port.\n" 2840#endif 2841#ifdef CONFIG_NETMAP 2842 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2843 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2844 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2845 " netmap device, defaults to '/dev/netmap')\n" 2846#endif 2847#ifdef CONFIG_POSIX 2848 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2849 " configure a vhost-user network, backed by a chardev 'dev'\n" 2850#endif 2851#ifdef __linux__ 2852 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2853 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2854 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2855 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2856#endif 2857#ifdef CONFIG_VMNET 2858 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2859 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2860 " configure a vmnet network backend in host mode with ID 'str',\n" 2861 " isolate this interface from others with 'isolated',\n" 2862 " configure the address range and choose a subnet mask,\n" 2863 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2864 " vmnet-host interfaces within this isolated network\n" 2865 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2866 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2867 " configure a vmnet network backend in shared mode with ID 'str',\n" 2868 " configure the address range and choose a subnet mask,\n" 2869 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2870 " isolate this interface from others with 'isolated'\n" 2871 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2872 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2873 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2874 " isolate this interface from others with 'isolated'\n" 2875#endif 2876 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2877 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2878DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2879 "-nic [tap|bridge|" 2880#ifdef CONFIG_SLIRP 2881 "user|" 2882#endif 2883#ifdef __linux__ 2884 "l2tpv3|" 2885#endif 2886#ifdef CONFIG_VDE 2887 "vde|" 2888#endif 2889#ifdef CONFIG_NETMAP 2890 "netmap|" 2891#endif 2892#ifdef CONFIG_POSIX 2893 "vhost-user|" 2894#endif 2895#ifdef CONFIG_VMNET 2896 "vmnet-host|vmnet-shared|vmnet-bridged|" 2897#endif 2898 "socket][,option][,...][mac=macaddr]\n" 2899 " initialize an on-board / default host NIC (using MAC address\n" 2900 " macaddr) and connect it to the given host network backend\n" 2901 "-nic none use it alone to have zero network devices (the default is to\n" 2902 " provided a 'user' network connection)\n", 2903 QEMU_ARCH_ALL) 2904DEF("net", HAS_ARG, QEMU_OPTION_net, 2905 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2906 " configure or create an on-board (or machine default) NIC and\n" 2907 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2908 "-net [" 2909#ifdef CONFIG_SLIRP 2910 "user|" 2911#endif 2912 "tap|" 2913 "bridge|" 2914#ifdef CONFIG_VDE 2915 "vde|" 2916#endif 2917#ifdef CONFIG_NETMAP 2918 "netmap|" 2919#endif 2920#ifdef CONFIG_VMNET 2921 "vmnet-host|vmnet-shared|vmnet-bridged|" 2922#endif 2923 "socket][,option][,option][,...]\n" 2924 " old way to initialize a host network interface\n" 2925 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2926SRST 2927``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2928 This option is a shortcut for configuring both the on-board 2929 (default) guest NIC hardware and the host network backend in one go. 2930 The host backend options are the same as with the corresponding 2931 ``-netdev`` options below. The guest NIC model can be set with 2932 ``model=modelname``. Use ``model=help`` to list the available device 2933 types. The hardware MAC address can be set with ``mac=macaddr``. 2934 2935 The following two example do exactly the same, to show how ``-nic`` 2936 can be used to shorten the command line length: 2937 2938 .. parsed-literal:: 2939 2940 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2941 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2942 2943``-nic none`` 2944 Indicate that no network devices should be configured. It is used to 2945 override the default configuration (default NIC with "user" host 2946 network backend) which is activated if no other networking options 2947 are provided. 2948 2949``-netdev user,id=id[,option][,option][,...]`` 2950 Configure user mode host network backend which requires no 2951 administrator privilege to run. Valid options are: 2952 2953 ``id=id`` 2954 Assign symbolic name for use in monitor commands. 2955 2956 ``ipv4=on|off and ipv6=on|off`` 2957 Specify that either IPv4 or IPv6 must be enabled. If neither is 2958 specified both protocols are enabled. 2959 2960 ``net=addr[/mask]`` 2961 Set IP network address the guest will see. Optionally specify 2962 the netmask, either in the form a.b.c.d or as number of valid 2963 top-most bits. Default is 10.0.2.0/24. 2964 2965 ``host=addr`` 2966 Specify the guest-visible address of the host. Default is the 2967 2nd IP in the guest network, i.e. x.x.x.2. 2968 2969 ``ipv6-net=addr[/int]`` 2970 Set IPv6 network address the guest will see (default is 2971 fec0::/64). The network prefix is given in the usual hexadecimal 2972 IPv6 address notation. The prefix size is optional, and is given 2973 as the number of valid top-most bits (default is 64). 2974 2975 ``ipv6-host=addr`` 2976 Specify the guest-visible IPv6 address of the host. Default is 2977 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2978 2979 ``restrict=on|off`` 2980 If this option is enabled, the guest will be isolated, i.e. it 2981 will not be able to contact the host and no guest IP packets 2982 will be routed over the host to the outside. This option does 2983 not affect any explicitly set forwarding rules. 2984 2985 ``hostname=name`` 2986 Specifies the client hostname reported by the built-in DHCP 2987 server. 2988 2989 ``dhcpstart=addr`` 2990 Specify the first of the 16 IPs the built-in DHCP server can 2991 assign. Default is the 15th to 31st IP in the guest network, 2992 i.e. x.x.x.15 to x.x.x.31. 2993 2994 ``dns=addr`` 2995 Specify the guest-visible address of the virtual nameserver. The 2996 address must be different from the host address. Default is the 2997 3rd IP in the guest network, i.e. x.x.x.3. 2998 2999 ``ipv6-dns=addr`` 3000 Specify the guest-visible address of the IPv6 virtual 3001 nameserver. The address must be different from the host address. 3002 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3003 3004 ``dnssearch=domain`` 3005 Provides an entry for the domain-search list sent by the 3006 built-in DHCP server. More than one domain suffix can be 3007 transmitted by specifying this option multiple times. If 3008 supported, this will cause the guest to automatically try to 3009 append the given domain suffix(es) in case a domain name can not 3010 be resolved. 3011 3012 Example: 3013 3014 .. parsed-literal:: 3015 3016 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3017 3018 ``domainname=domain`` 3019 Specifies the client domain name reported by the built-in DHCP 3020 server. 3021 3022 ``tftp=dir`` 3023 When using the user mode network stack, activate a built-in TFTP 3024 server. The files in dir will be exposed as the root of a TFTP 3025 server. The TFTP client on the guest must be configured in 3026 binary mode (use the command ``bin`` of the Unix TFTP client). 3027 3028 ``tftp-server-name=name`` 3029 In BOOTP reply, broadcast name as the "TFTP server name" 3030 (RFC2132 option 66). This can be used to advise the guest to 3031 load boot files or configurations from a different server than 3032 the host address. 3033 3034 ``bootfile=file`` 3035 When using the user mode network stack, broadcast file as the 3036 BOOTP filename. In conjunction with ``tftp``, this can be used 3037 to network boot a guest from a local directory. 3038 3039 Example (using pxelinux): 3040 3041 .. parsed-literal:: 3042 3043 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3044 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3045 3046 ``smb=dir[,smbserver=addr]`` 3047 When using the user mode network stack, activate a built-in SMB 3048 server so that Windows OSes can access to the host files in 3049 ``dir`` transparently. The IP address of the SMB server can be 3050 set to addr. By default the 4th IP in the guest network is used, 3051 i.e. x.x.x.4. 3052 3053 In the guest Windows OS, the line: 3054 3055 :: 3056 3057 10.0.2.4 smbserver 3058 3059 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3060 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3061 NT/2000). 3062 3063 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3064 3065 Note that a SAMBA server must be installed on the host OS. 3066 3067 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3068 Redirect incoming TCP or UDP connections to the host port 3069 hostport to the guest IP address guestaddr on guest port 3070 guestport. If guestaddr is not specified, its value is x.x.x.15 3071 (default first address given by the built-in DHCP server). By 3072 specifying hostaddr, the rule can be bound to a specific host 3073 interface. If no connection type is set, TCP is used. This 3074 option can be given multiple times. 3075 3076 For example, to redirect host X11 connection from screen 1 to 3077 guest screen 0, use the following: 3078 3079 .. parsed-literal:: 3080 3081 # on the host 3082 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3083 # this host xterm should open in the guest X11 server 3084 xterm -display :1 3085 3086 To redirect telnet connections from host port 5555 to telnet 3087 port on the guest, use the following: 3088 3089 .. parsed-literal:: 3090 3091 # on the host 3092 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3093 telnet localhost 5555 3094 3095 Then when you use on the host ``telnet localhost 5555``, you 3096 connect to the guest telnet server. 3097 3098 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3099 Forward guest TCP connections to the IP address server on port 3100 port to the character device dev or to a program executed by 3101 cmd:command which gets spawned for each connection. This option 3102 can be given multiple times. 3103 3104 You can either use a chardev directly and have that one used 3105 throughout QEMU's lifetime, like in the following example: 3106 3107 .. parsed-literal:: 3108 3109 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3110 # the guest accesses it 3111 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3112 3113 Or you can execute a command on every TCP connection established 3114 by the guest, so that QEMU behaves similar to an inetd process 3115 for that virtual server: 3116 3117 .. parsed-literal:: 3118 3119 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3120 # and connect the TCP stream to its stdin/stdout 3121 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3122 3123``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3124 Configure a host TAP network backend with ID id. 3125 3126 Use the network script file to configure it and the network script 3127 dfile to deconfigure it. If name is not provided, the OS 3128 automatically provides one. The default network configure script is 3129 ``/etc/qemu-ifup`` and the default network deconfigure script is 3130 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3131 disable script execution. 3132 3133 If running QEMU as an unprivileged user, use the network helper 3134 to configure the TAP interface and attach it to the bridge. 3135 The default network helper executable is 3136 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3137 ``br0``. 3138 3139 ``fd``\ =h can be used to specify the handle of an already opened 3140 host TAP interface. 3141 3142 Examples: 3143 3144 .. parsed-literal:: 3145 3146 #launch a QEMU instance with the default network script 3147 |qemu_system| linux.img -nic tap 3148 3149 .. parsed-literal:: 3150 3151 #launch a QEMU instance with two NICs, each one connected 3152 #to a TAP device 3153 |qemu_system| linux.img \\ 3154 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3155 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3156 3157 .. parsed-literal:: 3158 3159 #launch a QEMU instance with the default network helper to 3160 #connect a TAP device to bridge br0 3161 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3162 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3163 3164``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3165 Connect a host TAP network interface to a host bridge device. 3166 3167 Use the network helper helper to configure the TAP interface and 3168 attach it to the bridge. The default network helper executable is 3169 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3170 ``br0``. 3171 3172 Examples: 3173 3174 .. parsed-literal:: 3175 3176 #launch a QEMU instance with the default network helper to 3177 #connect a TAP device to bridge br0 3178 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3179 3180 .. parsed-literal:: 3181 3182 #launch a QEMU instance with the default network helper to 3183 #connect a TAP device to bridge qemubr0 3184 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3185 3186``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3187 This host network backend can be used to connect the guest's network 3188 to another QEMU virtual machine using a TCP socket connection. If 3189 ``listen`` is specified, QEMU waits for incoming connections on port 3190 (host is optional). ``connect`` is used to connect to another QEMU 3191 instance using the ``listen`` option. ``fd``\ =h specifies an 3192 already opened TCP socket. 3193 3194 Example: 3195 3196 .. parsed-literal:: 3197 3198 # launch a first QEMU instance 3199 |qemu_system| linux.img \\ 3200 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3201 -netdev socket,id=n1,listen=:1234 3202 # connect the network of this instance to the network of the first instance 3203 |qemu_system| linux.img \\ 3204 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3205 -netdev socket,id=n2,connect=127.0.0.1:1234 3206 3207``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3208 Configure a socket host network backend to share the guest's network 3209 traffic with another QEMU virtual machines using a UDP multicast 3210 socket, effectively making a bus for every QEMU with same multicast 3211 address maddr and port. NOTES: 3212 3213 1. Several QEMU can be running on different hosts and share same bus 3214 (assuming correct multicast setup for these hosts). 3215 3216 2. mcast support is compatible with User Mode Linux (argument 3217 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3218 3219 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3220 3221 Example: 3222 3223 .. parsed-literal:: 3224 3225 # launch one QEMU instance 3226 |qemu_system| linux.img \\ 3227 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3228 -netdev socket,id=n1,mcast=230.0.0.1:1234 3229 # launch another QEMU instance on same "bus" 3230 |qemu_system| linux.img \\ 3231 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3232 -netdev socket,id=n2,mcast=230.0.0.1:1234 3233 # launch yet another QEMU instance on same "bus" 3234 |qemu_system| linux.img \\ 3235 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3236 -netdev socket,id=n3,mcast=230.0.0.1:1234 3237 3238 Example (User Mode Linux compat.): 3239 3240 .. parsed-literal:: 3241 3242 # launch QEMU instance (note mcast address selected is UML's default) 3243 |qemu_system| linux.img \\ 3244 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3245 -netdev socket,id=n1,mcast=239.192.168.1:1102 3246 # launch UML 3247 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3248 3249 Example (send packets from host's 1.2.3.4): 3250 3251 .. parsed-literal:: 3252 3253 |qemu_system| linux.img \\ 3254 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3255 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3256 3257``-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]`` 3258 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3259 is a popular protocol to transport Ethernet (and other Layer 2) data 3260 frames between two systems. It is present in routers, firewalls and 3261 the Linux kernel (from version 3.3 onwards). 3262 3263 This transport allows a VM to communicate to another VM, router or 3264 firewall directly. 3265 3266 ``src=srcaddr`` 3267 source address (mandatory) 3268 3269 ``dst=dstaddr`` 3270 destination address (mandatory) 3271 3272 ``udp`` 3273 select udp encapsulation (default is ip). 3274 3275 ``srcport=srcport`` 3276 source udp port. 3277 3278 ``dstport=dstport`` 3279 destination udp port. 3280 3281 ``ipv6`` 3282 force v6, otherwise defaults to v4. 3283 3284 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3285 Cookies are a weak form of security in the l2tpv3 specification. 3286 Their function is mostly to prevent misconfiguration. By default 3287 they are 32 bit. 3288 3289 ``cookie64`` 3290 Set cookie size to 64 bit instead of the default 32 3291 3292 ``counter=off`` 3293 Force a 'cut-down' L2TPv3 with no counter as in 3294 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3295 3296 ``pincounter=on`` 3297 Work around broken counter handling in peer. This may also help 3298 on networks which have packet reorder. 3299 3300 ``offset=offset`` 3301 Add an extra offset between header and data 3302 3303 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3304 the bridge br-lan on the remote Linux host 1.2.3.4: 3305 3306 .. parsed-literal:: 3307 3308 # Setup tunnel on linux host using raw ip as encapsulation 3309 # on 1.2.3.4 3310 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3311 encap udp udp_sport 16384 udp_dport 16384 3312 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3313 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3314 ifconfig vmtunnel0 mtu 1500 3315 ifconfig vmtunnel0 up 3316 brctl addif br-lan vmtunnel0 3317 3318 3319 # on 4.3.2.1 3320 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3321 3322 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3323 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3324 3325``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3326 Configure VDE backend to connect to PORT n of a vde switch running 3327 on host and listening for incoming connections on socketpath. Use 3328 GROUP groupname and MODE octalmode to change default ownership and 3329 permissions for communication port. This option is only available if 3330 QEMU has been compiled with vde support enabled. 3331 3332 Example: 3333 3334 .. parsed-literal:: 3335 3336 # launch vde switch 3337 vde_switch -F -sock /tmp/myswitch 3338 # launch QEMU instance 3339 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3340 3341``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3342 Establish a vhost-user netdev, backed by a chardev id. The chardev 3343 should be a unix domain socket backed one. The vhost-user uses a 3344 specifically defined protocol to pass vhost ioctl replacement 3345 messages to an application on the other end of the socket. On 3346 non-MSIX guests, the feature can be forced with vhostforce. Use 3347 'queues=n' to specify the number of queues to be created for 3348 multiqueue vhost-user. 3349 3350 Example: 3351 3352 :: 3353 3354 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3355 -numa node,memdev=mem \ 3356 -chardev socket,id=chr0,path=/path/to/socket \ 3357 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3358 -device virtio-net-pci,netdev=net0 3359 3360``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3361 Establish a vhost-vdpa netdev. 3362 3363 vDPA device is a device that uses a datapath which complies with 3364 the virtio specifications with a vendor specific control path. 3365 vDPA devices can be both physically located on the hardware or 3366 emulated by software. 3367 3368``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3369 Create a hub port on the emulated hub with ID hubid. 3370 3371 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3372 instead of a single netdev. Alternatively, you can also connect the 3373 hubport to another netdev with ID nd by using the ``netdev=nd`` 3374 option. 3375 3376``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3377 Legacy option to configure or create an on-board (or machine 3378 default) Network Interface Card(NIC) and connect it either to the 3379 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3380 If model is omitted, then the default NIC model associated with the 3381 machine type is used. Note that the default NIC model may change in 3382 future QEMU releases, so it is highly recommended to always specify 3383 a model. Optionally, the MAC address can be changed to mac, the 3384 device address set to addr (PCI cards only), and a name can be 3385 assigned for use in monitor commands. Optionally, for PCI cards, you 3386 can specify the number v of MSI-X vectors that the card should have; 3387 this option currently only affects virtio cards; set v = 0 to 3388 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3389 created. QEMU can emulate several different models of network card. 3390 Use ``-net nic,model=help`` for a list of available devices for your 3391 target. 3392 3393``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3394 Configure a host network backend (with the options corresponding to 3395 the same ``-netdev`` option) and connect it to the emulated hub 0 3396 (the default hub). Use name to specify the name of the hub port. 3397ERST 3398 3399DEFHEADING() 3400 3401DEFHEADING(Character device options:) 3402 3403DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3404 "-chardev help\n" 3405 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3406 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3407 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3408 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3409 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3410 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3411 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3412 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3413 " [,logfile=PATH][,logappend=on|off]\n" 3414 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3415 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3416 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3417 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3418 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3419 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3420#ifdef _WIN32 3421 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3422 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3423#else 3424 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3425 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3426#endif 3427#ifdef CONFIG_BRLAPI 3428 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3429#endif 3430#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3431 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3432 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3433#endif 3434#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3435 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3436#endif 3437#if defined(CONFIG_SPICE) 3438 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3439 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3440#endif 3441 , QEMU_ARCH_ALL 3442) 3443 3444SRST 3445The general form of a character device option is: 3446 3447``-chardev backend,id=id[,mux=on|off][,options]`` 3448 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3449 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3450 ``pty``, ``stdio``, ``braille``, ``parallel``, 3451 ``spicevmc``, ``spiceport``. The specific backend will determine the 3452 applicable options. 3453 3454 Use ``-chardev help`` to print all available chardev backend types. 3455 3456 All devices must have an id, which can be any string up to 127 3457 characters long. It is used to uniquely identify this device in 3458 other command line directives. 3459 3460 A character device may be used in multiplexing mode by multiple 3461 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3462 a "1:N" device, and here the "1" end is your specified chardev 3463 backend, and the "N" end is the various parts of QEMU that can talk 3464 to a chardev. If you create a chardev with ``id=myid`` and 3465 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3466 and you can then configure multiple front ends to use that chardev 3467 ID for their input/output. Up to four different front ends can be 3468 connected to a single multiplexed chardev. (Without multiplexing 3469 enabled, a chardev can only be used by a single front end.) For 3470 instance you could use this to allow a single stdio chardev to be 3471 used by two serial ports and the QEMU monitor: 3472 3473 :: 3474 3475 -chardev stdio,mux=on,id=char0 \ 3476 -mon chardev=char0,mode=readline \ 3477 -serial chardev:char0 \ 3478 -serial chardev:char0 3479 3480 You can have more than one multiplexer in a system configuration; 3481 for instance you could have a TCP port multiplexed between UART 0 3482 and UART 1, and stdio multiplexed between the QEMU monitor and a 3483 parallel port: 3484 3485 :: 3486 3487 -chardev stdio,mux=on,id=char0 \ 3488 -mon chardev=char0,mode=readline \ 3489 -parallel chardev:char0 \ 3490 -chardev tcp,...,mux=on,id=char1 \ 3491 -serial chardev:char1 \ 3492 -serial chardev:char1 3493 3494 When you're using a multiplexed character device, some escape 3495 sequences are interpreted in the input. See the chapter about 3496 :ref:`keys in the character backend multiplexer` in the 3497 System Emulation Users Guide for more details. 3498 3499 Note that some other command line options may implicitly create 3500 multiplexed character backends; for instance ``-serial mon:stdio`` 3501 creates a multiplexed stdio backend connected to the serial port and 3502 the QEMU monitor, and ``-nographic`` also multiplexes the console 3503 and the monitor to stdio. 3504 3505 There is currently no support for multiplexing in the other 3506 direction (where a single QEMU front end takes input and output from 3507 multiple chardevs). 3508 3509 Every backend supports the ``logfile`` option, which supplies the 3510 path to a file to record all data transmitted via the backend. The 3511 ``logappend`` option controls whether the log file will be truncated 3512 or appended to when opened. 3513 3514The available backends are: 3515 3516``-chardev null,id=id`` 3517 A void device. This device will not emit any data, and will drop any 3518 data it receives. The null backend does not take any options. 3519 3520``-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]`` 3521 Create a two-way stream socket, which can be either a TCP or a unix 3522 socket. A unix socket will be created if ``path`` is specified. 3523 Behaviour is undefined if TCP options are specified for a unix 3524 socket. 3525 3526 ``server=on|off`` specifies that the socket shall be a listening socket. 3527 3528 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3529 to connect to a listening socket. 3530 3531 ``telnet=on|off`` specifies that traffic on the socket should interpret 3532 telnet escape sequences. 3533 3534 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3535 communication. 3536 3537 ``reconnect`` sets the timeout for reconnecting on non-server 3538 sockets when the remote end goes away. qemu will delay this many 3539 seconds and then attempt to reconnect. Zero disables reconnecting, 3540 and is the default. 3541 3542 ``tls-creds`` requests enablement of the TLS protocol for 3543 encryption, and specifies the id of the TLS credentials to use for 3544 the handshake. The credentials must be previously created with the 3545 ``-object tls-creds`` argument. 3546 3547 ``tls-auth`` provides the ID of the QAuthZ authorization object 3548 against which the client's x509 distinguished name will be 3549 validated. This object is only resolved at time of use, so can be 3550 deleted and recreated on the fly while the chardev server is active. 3551 If missing, it will default to denying access. 3552 3553 TCP and unix socket options are given below: 3554 3555 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3556 ``host`` for a listening socket specifies the local address to 3557 be bound. For a connecting socket species the remote host to 3558 connect to. ``host`` is optional for listening sockets. If not 3559 specified it defaults to ``0.0.0.0``. 3560 3561 ``port`` for a listening socket specifies the local port to be 3562 bound. For a connecting socket specifies the port on the remote 3563 host to connect to. ``port`` can be given as either a port 3564 number or a service name. ``port`` is required. 3565 3566 ``to`` is only relevant to listening sockets. If it is 3567 specified, and ``port`` cannot be bound, QEMU will attempt to 3568 bind to subsequent ports up to and including ``to`` until it 3569 succeeds. ``to`` must be specified as a port number. 3570 3571 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3572 or IPv6 must be used. If neither is specified the socket may 3573 use either protocol. 3574 3575 ``nodelay=on|off`` disables the Nagle algorithm. 3576 3577 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3578 ``path`` specifies the local path of the unix socket. ``path`` 3579 is required. 3580 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3581 rather than the filesystem. Optional, defaults to false. 3582 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3583 rather than the full sun_path length. Optional, defaults to true. 3584 3585``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3586 Sends all traffic from the guest to a remote host over UDP. 3587 3588 ``host`` specifies the remote host to connect to. If not specified 3589 it defaults to ``localhost``. 3590 3591 ``port`` specifies the port on the remote host to connect to. 3592 ``port`` is required. 3593 3594 ``localaddr`` specifies the local address to bind to. If not 3595 specified it defaults to ``0.0.0.0``. 3596 3597 ``localport`` specifies the local port to bind to. If not specified 3598 any available local port will be used. 3599 3600 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3601 If neither is specified the device may use either protocol. 3602 3603``-chardev msmouse,id=id`` 3604 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3605 does not take any options. 3606 3607``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3608 Connect to a QEMU text console. ``vc`` may optionally be given a 3609 specific size. 3610 3611 ``width`` and ``height`` specify the width and height respectively 3612 of the console, in pixels. 3613 3614 ``cols`` and ``rows`` specify that the console be sized to fit a 3615 text console with the given dimensions. 3616 3617``-chardev ringbuf,id=id[,size=size]`` 3618 Create a ring buffer with fixed size ``size``. size must be a power 3619 of two and defaults to ``64K``. 3620 3621``-chardev file,id=id,path=path[,input-path=input-path]`` 3622 Log all traffic received from the guest to a file. 3623 3624 ``path`` specifies the path of the file to be opened. This file will 3625 be created if it does not already exist, and overwritten if it does. 3626 ``path`` is required. 3627 3628 If ``input-path`` is specified, this is the path of a second file 3629 which will be used for input. If ``input-path`` is not specified, 3630 no input will be available from the chardev. 3631 3632 Note that ``input-path`` is not supported on Windows hosts. 3633 3634``-chardev pipe,id=id,path=path`` 3635 Create a two-way connection to the guest. The behaviour differs 3636 slightly between Windows hosts and other hosts: 3637 3638 On Windows, a single duplex pipe will be created at 3639 ``\\.pipe\path``. 3640 3641 On other hosts, 2 pipes will be created called ``path.in`` and 3642 ``path.out``. Data written to ``path.in`` will be received by the 3643 guest. Data written by the guest can be read from ``path.out``. QEMU 3644 will not create these fifos, and requires them to be present. 3645 3646 ``path`` forms part of the pipe path as described above. ``path`` is 3647 required. 3648 3649``-chardev console,id=id`` 3650 Send traffic from the guest to QEMU's standard output. ``console`` 3651 does not take any options. 3652 3653 ``console`` is only available on Windows hosts. 3654 3655``-chardev serial,id=id,path=path`` 3656 Send traffic from the guest to a serial device on the host. 3657 3658 On Unix hosts serial will actually accept any tty device, not only 3659 serial lines. 3660 3661 ``path`` specifies the name of the serial device to open. 3662 3663``-chardev pty,id=id`` 3664 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3665 does not take any options. 3666 3667 ``pty`` is not available on Windows hosts. 3668 3669``-chardev stdio,id=id[,signal=on|off]`` 3670 Connect to standard input and standard output of the QEMU process. 3671 3672 ``signal`` controls if signals are enabled on the terminal, that 3673 includes exiting QEMU with the key sequence Control-c. This option 3674 is enabled by default, use ``signal=off`` to disable it. 3675 3676``-chardev braille,id=id`` 3677 Connect to a local BrlAPI server. ``braille`` does not take any 3678 options. 3679 3680``-chardev parallel,id=id,path=path`` 3681 \ 3682 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3683 hosts. 3684 3685 Connect to a local parallel port. 3686 3687 ``path`` specifies the path to the parallel port device. ``path`` is 3688 required. 3689 3690``-chardev spicevmc,id=id,debug=debug,name=name`` 3691 ``spicevmc`` is only available when spice support is built in. 3692 3693 ``debug`` debug level for spicevmc 3694 3695 ``name`` name of spice channel to connect to 3696 3697 Connect to a spice virtual machine channel, such as vdiport. 3698 3699``-chardev spiceport,id=id,debug=debug,name=name`` 3700 ``spiceport`` is only available when spice support is built in. 3701 3702 ``debug`` debug level for spicevmc 3703 3704 ``name`` name of spice port to connect to 3705 3706 Connect to a spice port, allowing a Spice client to handle the 3707 traffic identified by a name (preferably a fqdn). 3708ERST 3709 3710DEFHEADING() 3711 3712#ifdef CONFIG_TPM 3713DEFHEADING(TPM device options:) 3714 3715DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3716 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3717 " use path to provide path to a character device; default is /dev/tpm0\n" 3718 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3719 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3720 "-tpmdev emulator,id=id,chardev=dev\n" 3721 " configure the TPM device using chardev backend\n", 3722 QEMU_ARCH_ALL) 3723SRST 3724The general form of a TPM device option is: 3725 3726``-tpmdev backend,id=id[,options]`` 3727 The specific backend type will determine the applicable options. The 3728 ``-tpmdev`` option creates the TPM backend and requires a 3729 ``-device`` option that specifies the TPM frontend interface model. 3730 3731 Use ``-tpmdev help`` to print all available TPM backend types. 3732 3733The available backends are: 3734 3735``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3736 (Linux-host only) Enable access to the host's TPM using the 3737 passthrough driver. 3738 3739 ``path`` specifies the path to the host's TPM device, i.e., on a 3740 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3741 default ``/dev/tpm0`` is used. 3742 3743 ``cancel-path`` specifies the path to the host TPM device's sysfs 3744 entry allowing for cancellation of an ongoing TPM command. 3745 ``cancel-path`` is optional and by default QEMU will search for the 3746 sysfs entry to use. 3747 3748 Some notes about using the host's TPM with the passthrough driver: 3749 3750 The TPM device accessed by the passthrough driver must not be used 3751 by any other application on the host. 3752 3753 Since the host's firmware (BIOS/UEFI) has already initialized the 3754 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3755 the TPM again and may therefore not show a TPM-specific menu that 3756 would otherwise allow the user to configure the TPM, e.g., allow the 3757 user to enable/disable or activate/deactivate the TPM. Further, if 3758 TPM ownership is released from within a VM then the host's TPM will 3759 get disabled and deactivated. To enable and activate the TPM again 3760 afterwards, the host has to be rebooted and the user is required to 3761 enter the firmware's menu to enable and activate the TPM. If the TPM 3762 is left disabled and/or deactivated most TPM commands will fail. 3763 3764 To create a passthrough TPM use the following two options: 3765 3766 :: 3767 3768 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3769 3770 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3771 ``tpmdev=tpm0`` in the device option. 3772 3773``-tpmdev emulator,id=id,chardev=dev`` 3774 (Linux-host only) Enable access to a TPM emulator using Unix domain 3775 socket based chardev backend. 3776 3777 ``chardev`` specifies the unique ID of a character device backend 3778 that provides connection to the software TPM server. 3779 3780 To create a TPM emulator backend device with chardev socket backend: 3781 3782 :: 3783 3784 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3785ERST 3786 3787DEFHEADING() 3788 3789#endif 3790 3791DEFHEADING(Boot Image or Kernel specific:) 3792SRST 3793There are broadly 4 ways you can boot a system with QEMU. 3794 3795 - specify a firmware and let it control finding a kernel 3796 - specify a firmware and pass a hint to the kernel to boot 3797 - direct kernel image boot 3798 - manually load files into the guest's address space 3799 3800The third method is useful for quickly testing kernels but as there is 3801no firmware to pass configuration information to the kernel the 3802hardware must either be probeable, the kernel built for the exact 3803configuration or passed some configuration data (e.g. a DTB blob) 3804which tells the kernel what drivers it needs. This exact details are 3805often hardware specific. 3806 3807The final method is the most generic way of loading images into the 3808guest address space and used mostly for ``bare metal`` type 3809development where the reset vectors of the processor are taken into 3810account. 3811 3812ERST 3813 3814SRST 3815 3816For x86 machines and some other architectures ``-bios`` will generally 3817do the right thing with whatever it is given. For other machines the 3818more strict ``-pflash`` option needs an image that is sized for the 3819flash device for the given machine type. 3820 3821Please see the :ref:`system-targets-ref` section of the manual for 3822more detailed documentation. 3823 3824ERST 3825 3826DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3827 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3828SRST 3829``-bios file`` 3830 Set the filename for the BIOS. 3831ERST 3832 3833DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3834 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3835SRST 3836``-pflash file`` 3837 Use file as a parallel flash image. 3838ERST 3839 3840SRST 3841 3842The kernel options were designed to work with Linux kernels although 3843other things (like hypervisors) can be packaged up as a kernel 3844executable image. The exact format of a executable image is usually 3845architecture specific. 3846 3847The way in which the kernel is started (what address it is loaded at, 3848what if any information is passed to it via CPU registers, the state 3849of the hardware when it is started, and so on) is also architecture 3850specific. Typically it follows the specification laid down by the 3851Linux kernel for how kernels for that architecture must be started. 3852 3853ERST 3854 3855DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3856 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3857SRST 3858``-kernel bzImage`` 3859 Use bzImage as kernel image. The kernel can be either a Linux kernel 3860 or in multiboot format. 3861ERST 3862 3863DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3864 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3865SRST 3866``-append cmdline`` 3867 Use cmdline as kernel command line 3868ERST 3869 3870DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3871 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3872SRST 3873``-initrd file`` 3874 Use file as initial ram disk. 3875 3876``-initrd "file1 arg=foo,file2"`` 3877 This syntax is only available with multiboot. 3878 3879 Use file1 and file2 as modules and pass arg=foo as parameter to the 3880 first module. 3881ERST 3882 3883DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3884 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3885SRST 3886``-dtb file`` 3887 Use file as a device tree binary (dtb) image and pass it to the 3888 kernel on boot. 3889ERST 3890 3891SRST 3892 3893Finally you can also manually load images directly into the address 3894space of the guest. This is most useful for developers who already 3895know the layout of their guest and take care to ensure something sane 3896will happen when the reset vector executes. 3897 3898The generic loader can be invoked by using the loader device: 3899 3900``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3901 3902there is also the guest loader which operates in a similar way but 3903tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3904the guest image is: 3905 3906``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3907 3908ERST 3909 3910DEFHEADING() 3911 3912DEFHEADING(Debug/Expert options:) 3913 3914DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3915 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3916 " Policy for handling deprecated management interfaces\n" 3917 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3918 " Policy for handling unstable management interfaces\n", 3919 QEMU_ARCH_ALL) 3920SRST 3921``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3922 Set policy for handling deprecated management interfaces (experimental): 3923 3924 ``deprecated-input=accept`` (default) 3925 Accept deprecated commands and arguments 3926 ``deprecated-input=reject`` 3927 Reject deprecated commands and arguments 3928 ``deprecated-input=crash`` 3929 Crash on deprecated commands and arguments 3930 ``deprecated-output=accept`` (default) 3931 Emit deprecated command results and events 3932 ``deprecated-output=hide`` 3933 Suppress deprecated command results and events 3934 3935 Limitation: covers only syntactic aspects of QMP. 3936 3937``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3938 Set policy for handling unstable management interfaces (experimental): 3939 3940 ``unstable-input=accept`` (default) 3941 Accept unstable commands and arguments 3942 ``unstable-input=reject`` 3943 Reject unstable commands and arguments 3944 ``unstable-input=crash`` 3945 Crash on unstable commands and arguments 3946 ``unstable-output=accept`` (default) 3947 Emit unstable command results and events 3948 ``unstable-output=hide`` 3949 Suppress unstable command results and events 3950 3951 Limitation: covers only syntactic aspects of QMP. 3952ERST 3953 3954DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3955 "-fw_cfg [name=]<name>,file=<file>\n" 3956 " add named fw_cfg entry with contents from file\n" 3957 "-fw_cfg [name=]<name>,string=<str>\n" 3958 " add named fw_cfg entry with contents from string\n", 3959 QEMU_ARCH_ALL) 3960SRST 3961``-fw_cfg [name=]name,file=file`` 3962 Add named fw\_cfg entry with contents from file file. 3963 3964``-fw_cfg [name=]name,string=str`` 3965 Add named fw\_cfg entry with contents from string str. 3966 3967 The terminating NUL character of the contents of str will not be 3968 included as part of the fw\_cfg item data. To insert contents with 3969 embedded NUL characters, you have to use the file parameter. 3970 3971 The fw\_cfg entries are passed by QEMU through to the guest. 3972 3973 Example: 3974 3975 :: 3976 3977 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3978 3979 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3980 from ./my\_blob.bin. 3981ERST 3982 3983DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3984 "-serial dev redirect the serial port to char device 'dev'\n", 3985 QEMU_ARCH_ALL) 3986SRST 3987``-serial dev`` 3988 Redirect the virtual serial port to host character device dev. The 3989 default device is ``vc`` in graphical mode and ``stdio`` in non 3990 graphical mode. 3991 3992 This option can be used several times to simulate up to 4 serial 3993 ports. 3994 3995 Use ``-serial none`` to disable all serial ports. 3996 3997 Available character devices are: 3998 3999 ``vc[:WxH]`` 4000 Virtual console. Optionally, a width and height can be given in 4001 pixel with 4002 4003 :: 4004 4005 vc:800x600 4006 4007 It is also possible to specify width or height in characters: 4008 4009 :: 4010 4011 vc:80Cx24C 4012 4013 ``pty`` 4014 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4015 4016 ``none`` 4017 No device is allocated. 4018 4019 ``null`` 4020 void device 4021 4022 ``chardev:id`` 4023 Use a named character device defined with the ``-chardev`` 4024 option. 4025 4026 ``/dev/XXX`` 4027 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4028 port parameters are set according to the emulated ones. 4029 4030 ``/dev/parportN`` 4031 [Linux only, parallel port only] Use host parallel port N. 4032 Currently SPP and EPP parallel port features can be used. 4033 4034 ``file:filename`` 4035 Write output to filename. No character can be read. 4036 4037 ``stdio`` 4038 [Unix only] standard input/output 4039 4040 ``pipe:filename`` 4041 name pipe filename 4042 4043 ``COMn`` 4044 [Windows only] Use host serial port n 4045 4046 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4047 This implements UDP Net Console. When remote\_host or src\_ip 4048 are not specified they default to ``0.0.0.0``. When not using a 4049 specified src\_port a random port is automatically chosen. 4050 4051 If you just want a simple readonly console you can use 4052 ``netcat`` or ``nc``, by starting QEMU with: 4053 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4054 QEMU writes something to that port it will appear in the 4055 netconsole session. 4056 4057 If you plan to send characters back via netconsole or you want 4058 to stop and start QEMU a lot of times, you should have QEMU use 4059 the same source port each time by using something like ``-serial 4060 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4061 version of netcat which can listen to a TCP port and send and 4062 receive characters via udp. If you have a patched version of 4063 netcat which activates telnet remote echo and single char 4064 transfer, then you can use the following options to set up a 4065 netcat redirector to allow telnet on port 5555 to access the 4066 QEMU port. 4067 4068 ``QEMU Options:`` 4069 -serial udp::4555@:4556 4070 4071 ``netcat options:`` 4072 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4073 4074 ``telnet options:`` 4075 localhost 5555 4076 4077 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4078 The TCP Net Console has two modes of operation. It can send the 4079 serial I/O to a location or wait for a connection from a 4080 location. By default the TCP Net Console is sent to host at the 4081 port. If you use the ``server=on`` option QEMU will wait for a client 4082 socket application to connect to the port before continuing, 4083 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4084 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4085 option only applies if ``server=no`` is set, if the connection goes 4086 down it will attempt to reconnect at the given interval. If host 4087 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4088 time is accepted. You can use ``telnet=on`` to connect to the 4089 corresponding character device. 4090 4091 ``Example to send tcp console to 192.168.0.2 port 4444`` 4092 -serial tcp:192.168.0.2:4444 4093 4094 ``Example to listen and wait on port 4444 for connection`` 4095 -serial tcp::4444,server=on 4096 4097 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4098 -serial tcp:192.168.0.100:4444,server=on,wait=off 4099 4100 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4101 The telnet protocol is used instead of raw tcp sockets. The 4102 options work the same as if you had specified ``-serial tcp``. 4103 The difference is that the port acts like a telnet server or 4104 client using telnet option negotiation. This will also allow you 4105 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4106 supports sending the break sequence. Typically in unix telnet 4107 you do it with Control-] and then type "send break" followed by 4108 pressing the enter key. 4109 4110 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4111 The WebSocket protocol is used instead of raw tcp socket. The 4112 port acts as a WebSocket server. Client mode is not supported. 4113 4114 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4115 A unix domain socket is used instead of a tcp socket. The option 4116 works the same as if you had specified ``-serial tcp`` except 4117 the unix domain socket path is used for connections. 4118 4119 ``mon:dev_string`` 4120 This is a special option to allow the monitor to be multiplexed 4121 onto another serial port. The monitor is accessed with key 4122 sequence of Control-a and then pressing c. dev\_string should be 4123 any one of the serial devices specified above. An example to 4124 multiplex the monitor onto a telnet server listening on port 4125 4444 would be: 4126 4127 ``-serial mon:telnet::4444,server=on,wait=off`` 4128 4129 When the monitor is multiplexed to stdio in this way, Ctrl+C 4130 will not terminate QEMU any more but will be passed to the guest 4131 instead. 4132 4133 ``braille`` 4134 Braille device. This will use BrlAPI to display the braille 4135 output on a real or fake device. 4136 4137 ``msmouse`` 4138 Three button serial mouse. Configure the guest to use Microsoft 4139 protocol. 4140ERST 4141 4142DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4143 "-parallel dev redirect the parallel port to char device 'dev'\n", 4144 QEMU_ARCH_ALL) 4145SRST 4146``-parallel dev`` 4147 Redirect the virtual parallel port to host device dev (same devices 4148 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4149 to use hardware devices connected on the corresponding host parallel 4150 port. 4151 4152 This option can be used several times to simulate up to 3 parallel 4153 ports. 4154 4155 Use ``-parallel none`` to disable all parallel ports. 4156ERST 4157 4158DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4159 "-monitor dev redirect the monitor to char device 'dev'\n", 4160 QEMU_ARCH_ALL) 4161SRST 4162``-monitor dev`` 4163 Redirect the monitor to host device dev (same devices as the serial 4164 port). The default device is ``vc`` in graphical mode and ``stdio`` 4165 in non graphical mode. Use ``-monitor none`` to disable the default 4166 monitor. 4167ERST 4168DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4169 "-qmp dev like -monitor but opens in 'control' mode\n", 4170 QEMU_ARCH_ALL) 4171SRST 4172``-qmp dev`` 4173 Like -monitor but opens in 'control' mode. 4174ERST 4175DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4176 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4177 QEMU_ARCH_ALL) 4178SRST 4179``-qmp-pretty dev`` 4180 Like -qmp but uses pretty JSON formatting. 4181ERST 4182 4183DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4184 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4185SRST 4186``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4187 Setup monitor on chardev name. ``mode=control`` configures 4188 a QMP monitor (a JSON RPC-style protocol) and it is not the 4189 same as HMP, the human monitor that has a "(qemu)" prompt. 4190 ``pretty`` is only valid when ``mode=control``, 4191 turning on JSON pretty printing to ease 4192 human reading and debugging. 4193ERST 4194 4195DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4196 "-debugcon dev redirect the debug console to char device 'dev'\n", 4197 QEMU_ARCH_ALL) 4198SRST 4199``-debugcon dev`` 4200 Redirect the debug console to host device dev (same devices as the 4201 serial port). The debug console is an I/O port which is typically 4202 port 0xe9; writing to that I/O port sends output to this device. The 4203 default device is ``vc`` in graphical mode and ``stdio`` in non 4204 graphical mode. 4205ERST 4206 4207DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4208 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4209SRST 4210``-pidfile file`` 4211 Store the QEMU process PID in file. It is useful if you launch QEMU 4212 from a script. 4213ERST 4214 4215DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4216 "-singlestep deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL) 4217SRST 4218``-singlestep`` 4219 This is a deprecated synonym for the TCG accelerator property 4220 ``one-insn-per-tb``. 4221ERST 4222 4223DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4224 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4225 QEMU_ARCH_ALL) 4226SRST 4227``--preconfig`` 4228 Pause QEMU for interactive configuration before the machine is 4229 created, which allows querying and configuring properties that will 4230 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4231 exit the preconfig state and move to the next state (i.e. run guest 4232 if -S isn't used or pause the second time if -S is used). This 4233 option is experimental. 4234ERST 4235 4236DEF("S", 0, QEMU_OPTION_S, \ 4237 "-S freeze CPU at startup (use 'c' to start execution)\n", 4238 QEMU_ARCH_ALL) 4239SRST 4240``-S`` 4241 Do not start CPU at startup (you must type 'c' in the monitor). 4242ERST 4243 4244DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4245 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4246 " run qemu with overcommit hints\n" 4247 " mem-lock=on|off controls memory lock support (default: off)\n" 4248 " cpu-pm=on|off controls cpu power management (default: off)\n", 4249 QEMU_ARCH_ALL) 4250SRST 4251``-overcommit mem-lock=on|off`` 4252 \ 4253``-overcommit cpu-pm=on|off`` 4254 Run qemu with hints about host resource overcommit. The default is 4255 to assume that host overcommits all resources. 4256 4257 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4258 (disabled by default). This works when host memory is not 4259 overcommitted and reduces the worst-case latency for guest. 4260 4261 Guest ability to manage power state of host cpus (increasing latency 4262 for other processes on the same host cpu, but decreasing latency for 4263 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4264 works best when host CPU is not overcommitted. When used, host 4265 estimates of CPU cycle and power utilization will be incorrect, not 4266 taking into account guest idle time. 4267ERST 4268 4269DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4270 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4271 " the guest without waiting for gdb to connect; use -S too\n" 4272 " if you want it to not start execution.)\n", 4273 QEMU_ARCH_ALL) 4274SRST 4275``-gdb dev`` 4276 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4277 in the System Emulation Users Guide). Note that this option does not pause QEMU 4278 execution -- if you want QEMU to not start the guest until you 4279 connect with gdb and issue a ``continue`` command, you will need to 4280 also pass the ``-S`` option to QEMU. 4281 4282 The most usual configuration is to listen on a local TCP socket:: 4283 4284 -gdb tcp::3117 4285 4286 but you can specify other backends; UDP, pseudo TTY, or even stdio 4287 are all reasonable use cases. For example, a stdio connection 4288 allows you to start QEMU from within gdb and establish the 4289 connection via a pipe: 4290 4291 .. parsed-literal:: 4292 4293 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4294ERST 4295 4296DEF("s", 0, QEMU_OPTION_s, \ 4297 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4298 QEMU_ARCH_ALL) 4299SRST 4300``-s`` 4301 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4302 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4303ERST 4304 4305DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4306 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4307 QEMU_ARCH_ALL) 4308SRST 4309``-d item1[,...]`` 4310 Enable logging of specified items. Use '-d help' for a list of log 4311 items. 4312ERST 4313 4314DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4315 "-D logfile output log to logfile (default stderr)\n", 4316 QEMU_ARCH_ALL) 4317SRST 4318``-D logfile`` 4319 Output log in logfile instead of to stderr 4320ERST 4321 4322DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4323 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4324 QEMU_ARCH_ALL) 4325SRST 4326``-dfilter range1[,...]`` 4327 Filter debug output to that relevant to a range of target addresses. 4328 The filter spec can be either start+size, start-size or start..end 4329 where start end and size are the addresses and sizes required. For 4330 example: 4331 4332 :: 4333 4334 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4335 4336 Will dump output for any code in the 0x1000 sized block starting at 4337 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4338 another 0x1000 sized block starting at 0xffffffc00005f000. 4339ERST 4340 4341DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4342 "-seed number seed the pseudo-random number generator\n", 4343 QEMU_ARCH_ALL) 4344SRST 4345``-seed number`` 4346 Force the guest to use a deterministic pseudo-random number 4347 generator, seeded with number. This does not affect crypto routines 4348 within the host. 4349ERST 4350 4351DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4352 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4353 QEMU_ARCH_ALL) 4354SRST 4355``-L path`` 4356 Set the directory for the BIOS, VGA BIOS and keymaps. 4357 4358 To list all the data directories, use ``-L help``. 4359ERST 4360 4361DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4362 "-enable-kvm enable KVM full virtualization support\n", 4363 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4364 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4365SRST 4366``-enable-kvm`` 4367 Enable KVM full virtualization support. This option is only 4368 available if KVM support is enabled when compiling. 4369ERST 4370 4371DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4372 "-xen-domid id specify xen guest domain id\n", 4373 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4374DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4375 "-xen-attach attach to existing xen domain\n" 4376 " libxl will use this when starting QEMU\n", 4377 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4378DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4379 "-xen-domid-restrict restrict set of available xen operations\n" 4380 " to specified domain id. (Does not affect\n" 4381 " xenpv machine type).\n", 4382 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4383SRST 4384``-xen-domid id`` 4385 Specify xen guest domain id (XEN only). 4386 4387``-xen-attach`` 4388 Attach to existing xen domain. libxl will use this when starting 4389 QEMU (XEN only). Restrict set of available xen operations to 4390 specified domain id (XEN only). 4391ERST 4392 4393DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4394 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4395SRST 4396``-no-reboot`` 4397 Exit instead of rebooting. 4398ERST 4399 4400DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4401 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4402SRST 4403``-no-shutdown`` 4404 Don't exit QEMU on guest shutdown, but instead only stop the 4405 emulation. This allows for instance switching to monitor to commit 4406 changes to the disk image. 4407ERST 4408 4409DEF("action", HAS_ARG, QEMU_OPTION_action, 4410 "-action reboot=reset|shutdown\n" 4411 " action when guest reboots [default=reset]\n" 4412 "-action shutdown=poweroff|pause\n" 4413 " action when guest shuts down [default=poweroff]\n" 4414 "-action panic=pause|shutdown|exit-failure|none\n" 4415 " action when guest panics [default=shutdown]\n" 4416 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4417 " action when watchdog fires [default=reset]\n", 4418 QEMU_ARCH_ALL) 4419SRST 4420``-action event=action`` 4421 The action parameter serves to modify QEMU's default behavior when 4422 certain guest events occur. It provides a generic method for specifying the 4423 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4424 parameters. 4425 4426 Examples: 4427 4428 ``-action panic=none`` 4429 ``-action reboot=shutdown,shutdown=pause`` 4430 ``-device i6300esb -action watchdog=pause`` 4431 4432ERST 4433 4434DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4435 "-loadvm [tag|id]\n" \ 4436 " start right away with a saved state (loadvm in monitor)\n", 4437 QEMU_ARCH_ALL) 4438SRST 4439``-loadvm file`` 4440 Start right away with a saved state (``loadvm`` in monitor) 4441ERST 4442 4443#ifndef _WIN32 4444DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4445 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4446#endif 4447SRST 4448``-daemonize`` 4449 Daemonize the QEMU process after initialization. QEMU will not 4450 detach from standard IO until it is ready to receive connections on 4451 any of its devices. This option is a useful way for external 4452 programs to launch QEMU without having to cope with initialization 4453 race conditions. 4454ERST 4455 4456DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4457 "-option-rom rom load a file, rom, into the option ROM space\n", 4458 QEMU_ARCH_ALL) 4459SRST 4460``-option-rom file`` 4461 Load the contents of file as an option ROM. This option is useful to 4462 load things like EtherBoot. 4463ERST 4464 4465DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4466 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4467 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4468 QEMU_ARCH_ALL) 4469 4470SRST 4471``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4472 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4473 the current UTC or local time, respectively. ``localtime`` is 4474 required for correct date in MS-DOS or Windows. To start at a 4475 specific point in time, provide datetime in the format 4476 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4477 4478 By default the RTC is driven by the host system time. This allows 4479 using of the RTC as accurate reference clock inside the guest, 4480 specifically if the host time is smoothly following an accurate 4481 external reference clock, e.g. via NTP. If you want to isolate the 4482 guest time from the host, you can set ``clock`` to ``rt`` instead, 4483 which provides a host monotonic clock if host support it. To even 4484 prevent the RTC from progressing during suspension, you can set 4485 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4486 recommended especially in icount mode in order to preserve 4487 determinism; however, note that in icount mode the speed of the 4488 virtual clock is variable and can in general differ from the host 4489 clock. 4490 4491 Enable ``driftfix`` (i386 targets only) if you experience time drift 4492 problems, specifically with Windows' ACPI HAL. This option will try 4493 to figure out how many timer interrupts were not processed by the 4494 Windows guest and will re-inject them. 4495ERST 4496 4497DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4498 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4499 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4500 " instruction, enable aligning the host and virtual clocks\n" \ 4501 " or disable real time cpu sleeping, and optionally enable\n" \ 4502 " record-and-replay mode\n", QEMU_ARCH_ALL) 4503SRST 4504``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4505 Enable virtual instruction counter. The virtual cpu will execute one 4506 instruction every 2^N ns of virtual time. If ``auto`` is specified 4507 then the virtual cpu speed will be automatically adjusted to keep 4508 virtual time within a few seconds of real time. 4509 4510 Note that while this option can give deterministic behavior, it does 4511 not provide cycle accurate emulation. Modern CPUs contain 4512 superscalar out of order cores with complex cache hierarchies. The 4513 number of instructions executed often has little or no correlation 4514 with actual performance. 4515 4516 When the virtual cpu is sleeping, the virtual time will advance at 4517 default speed unless ``sleep=on`` is specified. With 4518 ``sleep=on``, the virtual time will jump to the next timer 4519 deadline instantly whenever the virtual cpu goes to sleep mode and 4520 will not advance if no timer is enabled. This behavior gives 4521 deterministic execution times from the guest point of view. 4522 The default if icount is enabled is ``sleep=off``. 4523 ``sleep=on`` cannot be used together with either ``shift=auto`` 4524 or ``align=on``. 4525 4526 ``align=on`` will activate the delay algorithm which will try to 4527 synchronise the host clock and the virtual clock. The goal is to 4528 have a guest running at the real frequency imposed by the shift 4529 option. Whenever the guest clock is behind the host clock and if 4530 ``align=on`` is specified then we print a message to the user to 4531 inform about the delay. Currently this option does not work when 4532 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4533 shift values for which the guest clock runs ahead of the host clock. 4534 Typically this happens when the shift value is high (how high 4535 depends on the host machine). The default if icount is enabled 4536 is ``align=off``. 4537 4538 When the ``rr`` option is specified deterministic record/replay is 4539 enabled. The ``rrfile=`` option must also be provided to 4540 specify the path to the replay log. In record mode data is written 4541 to this file, and in replay mode it is read back. 4542 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4543 name. In record mode, a new VM snapshot with the given name is created 4544 at the start of execution recording. In replay mode this option 4545 specifies the snapshot name used to load the initial VM state. 4546ERST 4547 4548DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4549 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4550 " action when watchdog fires [default=reset]\n", 4551 QEMU_ARCH_ALL) 4552SRST 4553``-watchdog-action action`` 4554 The action controls what QEMU will do when the watchdog timer 4555 expires. The default is ``reset`` (forcefully reset the guest). 4556 Other possible actions are: ``shutdown`` (attempt to gracefully 4557 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4558 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4559 guest), ``debug`` (print a debug message and continue), or ``none`` 4560 (do nothing). 4561 4562 Note that the ``shutdown`` action requires that the guest responds 4563 to ACPI signals, which it may not be able to do in the sort of 4564 situations where the watchdog would have expired, and thus 4565 ``-watchdog-action shutdown`` is not recommended for production use. 4566 4567 Examples: 4568 4569 ``-device i6300esb -watchdog-action pause`` 4570 4571ERST 4572 4573DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4574 "-echr chr set terminal escape character instead of ctrl-a\n", 4575 QEMU_ARCH_ALL) 4576SRST 4577``-echr numeric_ascii_value`` 4578 Change the escape character used for switching to the monitor when 4579 using monitor and serial sharing. The default is ``0x01`` when using 4580 the ``-nographic`` option. ``0x01`` is equal to pressing 4581 ``Control-a``. You can select a different character from the ascii 4582 control keys where 1 through 26 map to Control-a through Control-z. 4583 For instance you could use the either of the following to change the 4584 escape character to Control-t. 4585 4586 ``-echr 0x14``; \ ``-echr 20`` 4587 4588ERST 4589 4590DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4591 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4592 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4593 "-incoming unix:socketpath\n" \ 4594 " prepare for incoming migration, listen on\n" \ 4595 " specified protocol and socket address\n" \ 4596 "-incoming fd:fd\n" \ 4597 "-incoming exec:cmdline\n" \ 4598 " accept incoming migration on given file descriptor\n" \ 4599 " or from given external command\n" \ 4600 "-incoming defer\n" \ 4601 " wait for the URI to be specified via migrate_incoming\n", 4602 QEMU_ARCH_ALL) 4603SRST 4604``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4605 \ 4606``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4607 Prepare for incoming migration, listen on a given tcp port. 4608 4609``-incoming unix:socketpath`` 4610 Prepare for incoming migration, listen on a given unix socket. 4611 4612``-incoming fd:fd`` 4613 Accept incoming migration from a given filedescriptor. 4614 4615``-incoming exec:cmdline`` 4616 Accept incoming migration as an output from specified external 4617 command. 4618 4619``-incoming defer`` 4620 Wait for the URI to be specified via migrate\_incoming. The monitor 4621 can be used to change settings (such as migration parameters) prior 4622 to issuing the migrate\_incoming to allow the migration to begin. 4623ERST 4624 4625DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4626 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4627SRST 4628``-only-migratable`` 4629 Only allow migratable devices. Devices will not be allowed to enter 4630 an unmigratable state. 4631ERST 4632 4633DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4634 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4635SRST 4636``-nodefaults`` 4637 Don't create default devices. Normally, QEMU sets the default 4638 devices like serial port, parallel port, virtual console, monitor 4639 device, VGA adapter, floppy and CD-ROM drive and others. The 4640 ``-nodefaults`` option will disable all those default devices. 4641ERST 4642 4643#ifndef _WIN32 4644DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4645 "-chroot dir chroot to dir just before starting the VM\n", 4646 QEMU_ARCH_ALL) 4647#endif 4648SRST 4649``-chroot dir`` 4650 Immediately before starting guest execution, chroot to the specified 4651 directory. Especially useful in combination with -runas. 4652ERST 4653 4654#ifndef _WIN32 4655DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4656 "-runas user change to user id user just before starting the VM\n" \ 4657 " user can be numeric uid:gid instead\n", 4658 QEMU_ARCH_ALL) 4659#endif 4660SRST 4661``-runas user`` 4662 Immediately before starting guest execution, drop root privileges, 4663 switching to the specified user. 4664ERST 4665 4666DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4667 "-prom-env variable=value\n" 4668 " set OpenBIOS nvram variables\n", 4669 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4670SRST 4671``-prom-env variable=value`` 4672 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4673 4674 :: 4675 4676 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4677 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4678 4679 :: 4680 4681 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4682 -prom-env 'boot-device=hd:2,\yaboot' \ 4683 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4684ERST 4685DEF("semihosting", 0, QEMU_OPTION_semihosting, 4686 "-semihosting semihosting mode\n", 4687 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4688 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4689SRST 4690``-semihosting`` 4691 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4692 4693 .. warning:: 4694 Note that this allows guest direct access to the host filesystem, so 4695 should only be used with a trusted guest OS. 4696 4697 See the -semihosting-config option documentation for further 4698 information about the facilities this enables. 4699ERST 4700DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4701 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4702 " semihosting configuration\n", 4703QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4704QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4705SRST 4706``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4707 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4708 only). 4709 4710 .. warning:: 4711 Note that this allows guest direct access to the host filesystem, so 4712 should only be used with a trusted guest OS. 4713 4714 ``target=native|gdb|auto`` 4715 Defines where the semihosting calls will be addressed, to QEMU 4716 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4717 means ``gdb`` during debug sessions and ``native`` otherwise. 4718 4719 ``chardev=str1`` 4720 Send the output to a chardev backend output for native or auto 4721 output when not in gdb 4722 4723 ``userspace=on|off`` 4724 Allows code running in guest userspace to access the semihosting 4725 interface. The default is that only privileged guest code can 4726 make semihosting calls. Note that setting ``userspace=on`` should 4727 only be used if all guest code is trusted (for example, in 4728 bare-metal test case code). 4729 4730 ``arg=str1,arg=str2,...`` 4731 Allows the user to pass input arguments, and can be used 4732 multiple times to build up a list. The old-style 4733 ``-kernel``/``-append`` method of passing a command line is 4734 still supported for backward compatibility. If both the 4735 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4736 specified, the former is passed to semihosting as it always 4737 takes precedence. 4738ERST 4739DEF("old-param", 0, QEMU_OPTION_old_param, 4740 "-old-param old param mode\n", QEMU_ARCH_ARM) 4741SRST 4742``-old-param`` 4743 Old param mode (ARM only). 4744ERST 4745 4746DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4747 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4748 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4749 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4750 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4751 " by the kernel, but typically no longer used by modern\n" \ 4752 " C library implementations.\n" \ 4753 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4754 " to elevate privileges using set*uid|gid system calls.\n" \ 4755 " The value 'children' will deny set*uid|gid system calls for\n" \ 4756 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4757 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4758 " blocking *fork and execve\n" \ 4759 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4760 QEMU_ARCH_ALL) 4761SRST 4762``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4763 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4764 filtering and 'off' will disable it. The default is 'off'. 4765 4766 ``obsolete=string`` 4767 Enable Obsolete system calls 4768 4769 ``elevateprivileges=string`` 4770 Disable set\*uid\|gid system calls 4771 4772 ``spawn=string`` 4773 Disable \*fork and execve 4774 4775 ``resourcecontrol=string`` 4776 Disable process affinity and schedular priority 4777ERST 4778 4779DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4780 "-readconfig <file>\n" 4781 " read config file\n", QEMU_ARCH_ALL) 4782SRST 4783``-readconfig file`` 4784 Read device configuration from file. This approach is useful when 4785 you want to spawn QEMU process with many command line options but 4786 you don't want to exceed the command line character limit. 4787ERST 4788 4789DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4790 "-no-user-config\n" 4791 " do not load default user-provided config files at startup\n", 4792 QEMU_ARCH_ALL) 4793SRST 4794``-no-user-config`` 4795 The ``-no-user-config`` option makes QEMU not load any of the 4796 user-provided config files on sysconfdir. 4797ERST 4798 4799DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4800 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4801 " specify tracing options\n", 4802 QEMU_ARCH_ALL) 4803SRST 4804``-trace [[enable=]pattern][,events=file][,file=file]`` 4805 .. include:: ../qemu-option-trace.rst.inc 4806 4807ERST 4808DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4809 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4810 " load a plugin\n", 4811 QEMU_ARCH_ALL) 4812SRST 4813``-plugin file=file[,argname=argvalue]`` 4814 Load a plugin. 4815 4816 ``file=file`` 4817 Load the given plugin from a shared library file. 4818 4819 ``argname=argvalue`` 4820 Argument passed to the plugin. (Can be given multiple times.) 4821ERST 4822 4823HXCOMM Internal use 4824DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4825DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4826 4827#ifdef __linux__ 4828DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4829 "-async-teardown enable asynchronous teardown\n", 4830 QEMU_ARCH_ALL) 4831#endif 4832SRST 4833``-async-teardown`` 4834 Enable asynchronous teardown. A new process called "cleanup/<QEMU_PID>" 4835 will be created at startup sharing the address space with the main qemu 4836 process, using clone. It will wait for the main qemu process to 4837 terminate completely, and then exit. 4838 This allows qemu to terminate very quickly even if the guest was 4839 huge, leaving the teardown of the address space to the cleanup 4840 process. Since the cleanup process shares the same cgroups as the 4841 main qemu process, accounting is performed correctly. This only 4842 works if the cleanup process is not forcefully killed with SIGKILL 4843 before the main qemu process has terminated completely. 4844ERST 4845 4846DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4847 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4848 " control error message format\n" 4849 " timestamp=on enables timestamps (default: off)\n" 4850 " guest-name=on enables guest name prefix but only if\n" 4851 " -name guest option is set (default: off)\n", 4852 QEMU_ARCH_ALL) 4853SRST 4854``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4855 Control error message format. 4856 4857 ``timestamp=on|off`` 4858 Prefix messages with a timestamp. Default is off. 4859 4860 ``guest-name=on|off`` 4861 Prefix messages with guest name but only if -name guest option is set 4862 otherwise the option is ignored. Default is off. 4863ERST 4864 4865DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4866 "-dump-vmstate <file>\n" 4867 " Output vmstate information in JSON format to file.\n" 4868 " Use the scripts/vmstate-static-checker.py file to\n" 4869 " check for possible regressions in migration code\n" 4870 " by comparing two such vmstate dumps.\n", 4871 QEMU_ARCH_ALL) 4872SRST 4873``-dump-vmstate file`` 4874 Dump json-encoded vmstate information for current machine type to 4875 file in file 4876ERST 4877 4878DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4879 "-enable-sync-profile\n" 4880 " enable synchronization profiling\n", 4881 QEMU_ARCH_ALL) 4882SRST 4883``-enable-sync-profile`` 4884 Enable synchronization profiling. 4885ERST 4886 4887#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 4888DEF("perfmap", 0, QEMU_OPTION_perfmap, 4889 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 4890 QEMU_ARCH_ALL) 4891SRST 4892``-perfmap`` 4893 Generate a map file for Linux perf tools that will allow basic profiling 4894 information to be broken down into basic blocks. 4895ERST 4896 4897DEF("jitdump", 0, QEMU_OPTION_jitdump, 4898 "-jitdump generate a jit-${pid}.dump file for perf\n", 4899 QEMU_ARCH_ALL) 4900SRST 4901``-jitdump`` 4902 Generate a dump file for Linux perf tools that maps basic blocks to symbol 4903 names, line numbers and JITted code. 4904ERST 4905#endif 4906 4907DEFHEADING() 4908 4909DEFHEADING(Generic object creation:) 4910 4911DEF("object", HAS_ARG, QEMU_OPTION_object, 4912 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4913 " create a new object of type TYPENAME setting properties\n" 4914 " in the order they are specified. Note that the 'id'\n" 4915 " property must be set. These objects are placed in the\n" 4916 " '/objects' path.\n", 4917 QEMU_ARCH_ALL) 4918SRST 4919``-object typename[,prop1=value1,...]`` 4920 Create a new object of type typename setting properties in the order 4921 they are specified. Note that the 'id' property must be set. These 4922 objects are placed in the '/objects' path. 4923 4924 ``-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,readonly=on|off`` 4925 Creates a memory file backend object, which can be used to back 4926 the guest RAM with huge pages. 4927 4928 The ``id`` parameter is a unique ID that will be used to 4929 reference this memory region in other parameters, e.g. ``-numa``, 4930 ``-device nvdimm``, etc. 4931 4932 The ``size`` option provides the size of the memory region, and 4933 accepts common suffixes, e.g. ``500M``. 4934 4935 The ``mem-path`` provides the path to either a shared memory or 4936 huge page filesystem mount. 4937 4938 The ``share`` boolean option determines whether the memory 4939 region is marked as private to QEMU, or shared. The latter 4940 allows a co-operating external process to access the QEMU memory 4941 region. 4942 4943 The ``share`` is also required for pvrdma devices due to 4944 limitations in the RDMA API provided by Linux. 4945 4946 Setting share=on might affect the ability to configure NUMA 4947 bindings for the memory backend under some circumstances, see 4948 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4949 source tree for additional details. 4950 4951 Setting the ``discard-data`` boolean option to on indicates that 4952 file contents can be destroyed when QEMU exits, to avoid 4953 unnecessarily flushing data to the backing file. Note that 4954 ``discard-data`` is only an optimization, and QEMU might not 4955 discard file contents if it aborts unexpectedly or is terminated 4956 using SIGKILL. 4957 4958 The ``merge`` boolean option enables memory merge, also known as 4959 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4960 the pages for memory deduplication. 4961 4962 Setting the ``dump`` boolean option to off excludes the memory 4963 from core dumps. This feature is also known as MADV\_DONTDUMP. 4964 4965 The ``prealloc`` boolean option enables memory preallocation. 4966 4967 The ``host-nodes`` option binds the memory range to a list of 4968 NUMA host nodes. 4969 4970 The ``policy`` option sets the NUMA policy to one of the 4971 following values: 4972 4973 ``default`` 4974 default host policy 4975 4976 ``preferred`` 4977 prefer the given host node list for allocation 4978 4979 ``bind`` 4980 restrict memory allocation to the given host node list 4981 4982 ``interleave`` 4983 interleave memory allocations across the given host node 4984 list 4985 4986 The ``align`` option specifies the base address alignment when 4987 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4988 ``2M``. Some backend store specified by ``mem-path`` requires an 4989 alignment different than the default one used by QEMU, eg the 4990 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4991 such cases, users can specify the required alignment via this 4992 option. 4993 4994 The ``pmem`` option specifies whether the backing file specified 4995 by ``mem-path`` is in host persistent memory that can be 4996 accessed using the SNIA NVM programming model (e.g. Intel 4997 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4998 operations to guarantee the persistence of its own writes to 4999 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5000 migration). Also, we will map the backend-file with MAP\_SYNC 5001 flag, which ensures the file metadata is in sync for 5002 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5003 requires support from both the host kernel (since Linux kernel 5004 4.15) and the filesystem of ``mem-path`` mounted with DAX 5005 option. 5006 5007 The ``readonly`` option specifies whether the backing file is opened 5008 read-only or read-write (default). 5009 5010 ``-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`` 5011 Creates a memory backend object, which can be used to back the 5012 guest RAM. Memory backend objects offer more control than the 5013 ``-m`` option that is traditionally used to define guest RAM. 5014 Please refer to ``memory-backend-file`` for a description of the 5015 options. 5016 5017 ``-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`` 5018 Creates an anonymous memory file backend object, which allows 5019 QEMU to share the memory with an external process (e.g. when 5020 using vhost-user). The memory is allocated with memfd and 5021 optional sealing. (Linux only) 5022 5023 The ``seal`` option creates a sealed-file, that will block 5024 further resizing the memory ('on' by default). 5025 5026 The ``hugetlb`` option specify the file to be created resides in 5027 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5028 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5029 the hugetlb page size on systems that support multiple hugetlb 5030 page sizes (it must be a power of 2 value supported by the 5031 system). 5032 5033 In some versions of Linux, the ``hugetlb`` option is 5034 incompatible with the ``seal`` option (requires at least Linux 5035 4.16). 5036 5037 Please refer to ``memory-backend-file`` for a description of the 5038 other options. 5039 5040 The ``share`` boolean option is on by default with memfd. 5041 5042 ``-object rng-builtin,id=id`` 5043 Creates a random number generator backend which obtains entropy 5044 from QEMU builtin functions. The ``id`` parameter is a unique ID 5045 that will be used to reference this entropy backend from the 5046 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5047 uses this RNG backend. 5048 5049 ``-object rng-random,id=id,filename=/dev/random`` 5050 Creates a random number generator backend which obtains entropy 5051 from a device on the host. The ``id`` parameter is a unique ID 5052 that will be used to reference this entropy backend from the 5053 ``virtio-rng`` device. The ``filename`` parameter specifies 5054 which file to obtain entropy from and if omitted defaults to 5055 ``/dev/urandom``. 5056 5057 ``-object rng-egd,id=id,chardev=chardevid`` 5058 Creates a random number generator backend which obtains entropy 5059 from an external daemon running on the host. The ``id`` 5060 parameter is a unique ID that will be used to reference this 5061 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5062 parameter is the unique ID of a character device backend that 5063 provides the connection to the RNG daemon. 5064 5065 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5066 Creates a TLS anonymous credentials object, which can be used to 5067 provide TLS support on network backends. The ``id`` parameter is 5068 a unique ID which network backends will use to access the 5069 credentials. The ``endpoint`` is either ``server`` or ``client`` 5070 depending on whether the QEMU network backend that uses the 5071 credentials will be acting as a client or as a server. If 5072 ``verify-peer`` is enabled (the default) then once the handshake 5073 is completed, the peer credentials will be verified, though this 5074 is a no-op for anonymous credentials. 5075 5076 The dir parameter tells QEMU where to find the credential files. 5077 For server endpoints, this directory may contain a file 5078 dh-params.pem providing diffie-hellman parameters to use for the 5079 TLS server. If the file is missing, QEMU will generate a set of 5080 DH parameters at startup. This is a computationally expensive 5081 operation that consumes random pool entropy, so it is 5082 recommended that a persistent set of parameters be generated 5083 upfront and saved. 5084 5085 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5086 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5087 can be used to provide TLS support on network backends. The 5088 ``id`` parameter is a unique ID which network backends will use 5089 to access the credentials. The ``endpoint`` is either ``server`` 5090 or ``client`` depending on whether the QEMU network backend that 5091 uses the credentials will be acting as a client or as a server. 5092 For clients only, ``username`` is the username which will be 5093 sent to the server. If omitted it defaults to "qemu". 5094 5095 The dir parameter tells QEMU where to find the keys file. It is 5096 called "dir/keys.psk" and contains "username:key" pairs. This 5097 file can most easily be created using the GnuTLS ``psktool`` 5098 program. 5099 5100 For server endpoints, dir may also contain a file dh-params.pem 5101 providing diffie-hellman parameters to use for the TLS server. 5102 If the file is missing, QEMU will generate a set of DH 5103 parameters at startup. This is a computationally expensive 5104 operation that consumes random pool entropy, so it is 5105 recommended that a persistent set of parameters be generated up 5106 front and saved. 5107 5108 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5109 Creates a TLS anonymous credentials object, which can be used to 5110 provide TLS support on network backends. The ``id`` parameter is 5111 a unique ID which network backends will use to access the 5112 credentials. The ``endpoint`` is either ``server`` or ``client`` 5113 depending on whether the QEMU network backend that uses the 5114 credentials will be acting as a client or as a server. If 5115 ``verify-peer`` is enabled (the default) then once the handshake 5116 is completed, the peer credentials will be verified. With x509 5117 certificates, this implies that the clients must be provided 5118 with valid client certificates too. 5119 5120 The dir parameter tells QEMU where to find the credential files. 5121 For server endpoints, this directory may contain a file 5122 dh-params.pem providing diffie-hellman parameters to use for the 5123 TLS server. If the file is missing, QEMU will generate a set of 5124 DH parameters at startup. This is a computationally expensive 5125 operation that consumes random pool entropy, so it is 5126 recommended that a persistent set of parameters be generated 5127 upfront and saved. 5128 5129 For x509 certificate credentials the directory will contain 5130 further files providing the x509 certificates. The certificates 5131 must be stored in PEM format, in filenames ca-cert.pem, 5132 ca-crl.pem (optional), server-cert.pem (only servers), 5133 server-key.pem (only servers), client-cert.pem (only clients), 5134 and client-key.pem (only clients). 5135 5136 For the server-key.pem and client-key.pem files which contain 5137 sensitive private keys, it is possible to use an encrypted 5138 version by providing the passwordid parameter. This provides the 5139 ID of a previously created ``secret`` object containing the 5140 password for decryption. 5141 5142 The priority parameter allows to override the global default 5143 priority used by gnutls. This can be useful if the system 5144 administrator needs to use a weaker set of crypto priorities for 5145 QEMU without potentially forcing the weakness onto all 5146 applications. Or conversely if one wants wants a stronger 5147 default for QEMU than for all other applications, they can do 5148 this through this parameter. Its format is a gnutls priority 5149 string as described at 5150 https://gnutls.org/manual/html_node/Priority-Strings.html. 5151 5152 ``-object tls-cipher-suites,id=id,priority=priority`` 5153 Creates a TLS cipher suites object, which can be used to control 5154 the TLS cipher/protocol algorithms that applications are permitted 5155 to use. 5156 5157 The ``id`` parameter is a unique ID which frontends will use to 5158 access the ordered list of permitted TLS cipher suites from the 5159 host. 5160 5161 The ``priority`` parameter allows to override the global default 5162 priority used by gnutls. This can be useful if the system 5163 administrator needs to use a weaker set of crypto priorities for 5164 QEMU without potentially forcing the weakness onto all 5165 applications. Or conversely if one wants wants a stronger 5166 default for QEMU than for all other applications, they can do 5167 this through this parameter. Its format is a gnutls priority 5168 string as described at 5169 https://gnutls.org/manual/html_node/Priority-Strings.html. 5170 5171 An example of use of this object is to control UEFI HTTPS Boot. 5172 The tls-cipher-suites object exposes the ordered list of permitted 5173 TLS cipher suites from the host side to the guest firmware, via 5174 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5175 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5176 guest-side TLS. 5177 5178 In the following example, the priority at which the host-side policy 5179 is retrieved is given by the ``priority`` property. 5180 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5181 refer to /etc/crypto-policies/back-ends/gnutls.config. 5182 5183 .. parsed-literal:: 5184 5185 # |qemu_system| \\ 5186 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5187 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5188 5189 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5190 Interval t can't be 0, this filter batches the packet delivery: 5191 all packets arriving in a given interval on netdev netdevid are 5192 delayed until the end of the interval. Interval is in 5193 microseconds. ``status`` is optional that indicate whether the 5194 netfilter is on (enabled) or off (disabled), the default status 5195 for netfilter will be 'on'. 5196 5197 queue all\|rx\|tx is an option that can be applied to any 5198 netfilter. 5199 5200 ``all``: the filter is attached both to the receive and the 5201 transmit queue of the netdev (default). 5202 5203 ``rx``: the filter is attached to the receive queue of the 5204 netdev, where it will receive packets sent to the netdev. 5205 5206 ``tx``: the filter is attached to the transmit queue of the 5207 netdev, where it will receive packets sent by the netdev. 5208 5209 position head\|tail\|id=<id> is an option to specify where the 5210 filter should be inserted in the filter list. It can be applied 5211 to any netfilter. 5212 5213 ``head``: the filter is inserted at the head of the filter list, 5214 before any existing filters. 5215 5216 ``tail``: the filter is inserted at the tail of the filter list, 5217 behind any existing filters (default). 5218 5219 ``id=<id>``: the filter is inserted before or behind the filter 5220 specified by <id>, see the insert option below. 5221 5222 insert behind\|before is an option to specify where to insert 5223 the new filter relative to the one specified with 5224 position=id=<id>. It can be applied to any netfilter. 5225 5226 ``before``: insert before the specified filter. 5227 5228 ``behind``: insert behind the specified filter (default). 5229 5230 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5231 filter-mirror on netdev netdevid,mirror net packet to 5232 chardevchardevid, if it has the vnet\_hdr\_support flag, 5233 filter-mirror will mirror packet with vnet\_hdr\_len. 5234 5235 ``-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]`` 5236 filter-redirector on netdev netdevid,redirect filter's net 5237 packet to chardev chardevid,and redirect indev's packet to 5238 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5239 will redirect packet with vnet\_hdr\_len. Create a 5240 filter-redirector we need to differ outdev id from indev id, id 5241 can not be the same. we can just use indev or outdev, but at 5242 least one of indev or outdev need to be specified. 5243 5244 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5245 Filter-rewriter is a part of COLO project.It will rewrite tcp 5246 packet to secondary from primary to keep secondary tcp 5247 connection,and rewrite tcp packet to primary from secondary make 5248 tcp packet can be handled by client.if it has the 5249 vnet\_hdr\_support flag, we can parse packet with vnet header. 5250 5251 usage: colo secondary: -object 5252 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5253 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5254 filter-rewriter,id=rew0,netdev=hn0,queue=all 5255 5256 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5257 Dump the network traffic on netdev dev to the file specified by 5258 filename. At most len bytes (64k by default) per packet are 5259 stored. The file format is libpcap, so it can be analyzed with 5260 tools such as tcpdump or Wireshark. 5261 5262 ``-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}]`` 5263 Colo-compare gets packet from primary\_in chardevid and 5264 secondary\_in, then compare whether the payload of primary packet 5265 and secondary packet are the same. If same, it will output 5266 primary packet to out\_dev, else it will notify COLO-framework to do 5267 checkpoint and send primary packet to out\_dev. In order to 5268 improve efficiency, we need to put the task of comparison in 5269 another iothread. If it has the vnet\_hdr\_support flag, 5270 colo compare will send/recv packet with vnet\_hdr\_len. 5271 The compare\_timeout=@var{ms} determines the maximum time of the 5272 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5273 is to set the period of scanning expired primary node network packets. 5274 The max\_queue\_size=@var{size} is to set the max compare queue 5275 size depend on user environment. 5276 If user want to use Xen COLO, need to add the notify\_dev to 5277 notify Xen colo-frame to do checkpoint. 5278 5279 COLO-compare must be used with the help of filter-mirror, 5280 filter-redirector and filter-rewriter. 5281 5282 :: 5283 5284 KVM COLO 5285 5286 primary: 5287 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5288 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5289 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5290 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5291 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5292 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5293 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5294 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5295 -object iothread,id=iothread1 5296 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5297 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5298 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5299 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5300 5301 secondary: 5302 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5303 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5304 -chardev socket,id=red0,host=3.3.3.3,port=9003 5305 -chardev socket,id=red1,host=3.3.3.3,port=9004 5306 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5307 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5308 5309 5310 Xen COLO 5311 5312 primary: 5313 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5314 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5315 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5316 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5317 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5318 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5319 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5320 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5321 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5322 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5323 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5324 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5325 -object iothread,id=iothread1 5326 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5327 5328 secondary: 5329 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5330 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5331 -chardev socket,id=red0,host=3.3.3.3,port=9003 5332 -chardev socket,id=red1,host=3.3.3.3,port=9004 5333 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5334 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5335 5336 If you want to know the detail of above command line, you can 5337 read the colo-compare git log. 5338 5339 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5340 Creates a cryptodev backend which executes crypto operations from 5341 the QEMU cipher APIs. The id parameter is a unique ID that will 5342 be used to reference this cryptodev backend from the 5343 ``virtio-crypto`` device. The queues parameter is optional, 5344 which specify the queue number of cryptodev backend, the default 5345 of queues is 1. 5346 5347 .. parsed-literal:: 5348 5349 # |qemu_system| \\ 5350 [...] \\ 5351 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5352 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5353 [...] 5354 5355 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5356 Creates a vhost-user cryptodev backend, backed by a chardev 5357 chardevid. The id parameter is a unique ID that will be used to 5358 reference this cryptodev backend from the ``virtio-crypto`` 5359 device. The chardev should be a unix domain socket backed one. 5360 The vhost-user uses a specifically defined protocol to pass 5361 vhost ioctl replacement messages to an application on the other 5362 end of the socket. The queues parameter is optional, which 5363 specify the queue number of cryptodev backend for multiqueue 5364 vhost-user, the default of queues is 1. 5365 5366 .. parsed-literal:: 5367 5368 # |qemu_system| \\ 5369 [...] \\ 5370 -chardev socket,id=chardev0,path=/path/to/socket \\ 5371 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5372 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5373 [...] 5374 5375 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5376 \ 5377 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5378 Defines a secret to store a password, encryption key, or some 5379 other sensitive data. The sensitive data can either be passed 5380 directly via the data parameter, or indirectly via the file 5381 parameter. Using the data parameter is insecure unless the 5382 sensitive data is encrypted. 5383 5384 The sensitive data can be provided in raw format (the default), 5385 or base64. When encoded as JSON, the raw format only supports 5386 valid UTF-8 characters, so base64 is recommended for sending 5387 binary data. QEMU will convert from which ever format is 5388 provided to the format it needs internally. eg, an RBD password 5389 can be provided in raw format, even though it will be base64 5390 encoded when passed onto the RBD sever. 5391 5392 For added protection, it is possible to encrypt the data 5393 associated with a secret using the AES-256-CBC cipher. Use of 5394 encryption is indicated by providing the keyid and iv 5395 parameters. The keyid parameter provides the ID of a previously 5396 defined secret that contains the AES-256 decryption key. This 5397 key should be 32-bytes long and be base64 encoded. The iv 5398 parameter provides the random initialization vector used for 5399 encryption of this particular secret and should be a base64 5400 encrypted string of the 16-byte IV. 5401 5402 The simplest (insecure) usage is to provide the secret inline 5403 5404 .. parsed-literal:: 5405 5406 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5407 5408 The simplest secure usage is to provide the secret via a file 5409 5410 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5411 secret,id=sec0,file=mypasswd.txt,format=raw 5412 5413 For greater security, AES-256-CBC should be used. To illustrate 5414 usage, consider the openssl command line tool which can encrypt 5415 the data. Note that when encrypting, the plaintext must be 5416 padded to the cipher block size (32 bytes) using the standard 5417 PKCS#5/6 compatible padding algorithm. 5418 5419 First a master key needs to be created in base64 encoding: 5420 5421 :: 5422 5423 # openssl rand -base64 32 > key.b64 5424 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5425 5426 Each secret to be encrypted needs to have a random 5427 initialization vector generated. These do not need to be kept 5428 secret 5429 5430 :: 5431 5432 # openssl rand -base64 16 > iv.b64 5433 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5434 5435 The secret to be defined can now be encrypted, in this case 5436 we're telling openssl to base64 encode the result, but it could 5437 be left as raw bytes if desired. 5438 5439 :: 5440 5441 # SECRET=$(printf "letmein" | 5442 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5443 5444 When launching QEMU, create a master secret pointing to 5445 ``key.b64`` and specify that to be used to decrypt the user 5446 password. Pass the contents of ``iv.b64`` to the second secret 5447 5448 .. parsed-literal:: 5449 5450 # |qemu_system| \\ 5451 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5452 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5453 data=$SECRET,iv=$(<iv.b64) 5454 5455 ``-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]`` 5456 Create a Secure Encrypted Virtualization (SEV) guest object, 5457 which can be used to provide the guest memory encryption support 5458 on AMD processors. 5459 5460 When memory encryption is enabled, one of the physical address 5461 bit (aka the C-bit) is utilized to mark if a memory page is 5462 protected. The ``cbitpos`` is used to provide the C-bit 5463 position. The C-bit position is Host family dependent hence user 5464 must provide this value. On EPYC, the value should be 47. 5465 5466 When memory encryption is enabled, we loose certain bits in 5467 physical address space. The ``reduced-phys-bits`` is used to 5468 provide the number of bits we loose in physical address space. 5469 Similar to C-bit, the value is Host family dependent. On EPYC, 5470 a guest will lose a maximum of 1 bit, so the value should be 1. 5471 5472 The ``sev-device`` provides the device file to use for 5473 communicating with the SEV firmware running inside AMD Secure 5474 Processor. The default device is '/dev/sev'. If hardware 5475 supports memory encryption then /dev/sev devices are created by 5476 CCP driver. 5477 5478 The ``policy`` provides the guest policy to be enforced by the 5479 SEV firmware and restrict what configuration and operational 5480 commands can be performed on this guest by the hypervisor. The 5481 policy should be provided by the guest owner and is bound to the 5482 guest and cannot be changed throughout the lifetime of the 5483 guest. The default is 0. 5484 5485 If guest ``policy`` allows sharing the key with another SEV 5486 guest then ``handle`` can be use to provide handle of the guest 5487 from which to share the key. 5488 5489 The ``dh-cert-file`` and ``session-file`` provides the guest 5490 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5491 and session parameters are used for establishing a cryptographic 5492 session with the guest owner to negotiate keys used for 5493 attestation. The file must be encoded in base64. 5494 5495 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5496 cmdline to a designated guest firmware page for measured Linux 5497 boot with -kernel. The default is off. (Since 6.2) 5498 5499 e.g to launch a SEV guest 5500 5501 .. parsed-literal:: 5502 5503 # |qemu_system_x86| \\ 5504 ...... \\ 5505 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5506 -machine ...,memory-encryption=sev0 \\ 5507 ..... 5508 5509 ``-object authz-simple,id=id,identity=string`` 5510 Create an authorization object that will control access to 5511 network services. 5512 5513 The ``identity`` parameter is identifies the user and its format 5514 depends on the network service that authorization object is 5515 associated with. For authorizing based on TLS x509 certificates, 5516 the identity must be the x509 distinguished name. Note that care 5517 must be taken to escape any commas in the distinguished name. 5518 5519 An example authorization object to validate a x509 distinguished 5520 name would look like: 5521 5522 .. parsed-literal:: 5523 5524 # |qemu_system| \\ 5525 ... \\ 5526 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5527 ... 5528 5529 Note the use of quotes due to the x509 distinguished name 5530 containing whitespace, and escaping of ','. 5531 5532 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5533 Create an authorization object that will control access to 5534 network services. 5535 5536 The ``filename`` parameter is the fully qualified path to a file 5537 containing the access control list rules in JSON format. 5538 5539 An example set of rules that match against SASL usernames might 5540 look like: 5541 5542 :: 5543 5544 { 5545 "rules": [ 5546 { "match": "fred", "policy": "allow", "format": "exact" }, 5547 { "match": "bob", "policy": "allow", "format": "exact" }, 5548 { "match": "danb", "policy": "deny", "format": "glob" }, 5549 { "match": "dan*", "policy": "allow", "format": "exact" }, 5550 ], 5551 "policy": "deny" 5552 } 5553 5554 When checking access the object will iterate over all the rules 5555 and the first rule to match will have its ``policy`` value 5556 returned as the result. If no rules match, then the default 5557 ``policy`` value is returned. 5558 5559 The rules can either be an exact string match, or they can use 5560 the simple UNIX glob pattern matching to allow wildcards to be 5561 used. 5562 5563 If ``refresh`` is set to true the file will be monitored and 5564 automatically reloaded whenever its content changes. 5565 5566 As with the ``authz-simple`` object, the format of the identity 5567 strings being matched depends on the network service, but is 5568 usually a TLS x509 distinguished name, or a SASL username. 5569 5570 An example authorization object to validate a SASL username 5571 would look like: 5572 5573 .. parsed-literal:: 5574 5575 # |qemu_system| \\ 5576 ... \\ 5577 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5578 ... 5579 5580 ``-object authz-pam,id=id,service=string`` 5581 Create an authorization object that will control access to 5582 network services. 5583 5584 The ``service`` parameter provides the name of a PAM service to 5585 use for authorization. It requires that a file 5586 ``/etc/pam.d/service`` exist to provide the configuration for 5587 the ``account`` subsystem. 5588 5589 An example authorization object to validate a TLS x509 5590 distinguished name would look like: 5591 5592 .. parsed-literal:: 5593 5594 # |qemu_system| \\ 5595 ... \\ 5596 -object authz-pam,id=auth0,service=qemu-vnc \\ 5597 ... 5598 5599 There would then be a corresponding config file for PAM at 5600 ``/etc/pam.d/qemu-vnc`` that contains: 5601 5602 :: 5603 5604 account requisite pam_listfile.so item=user sense=allow \ 5605 file=/etc/qemu/vnc.allow 5606 5607 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5608 of x509 distinguished names that are permitted access 5609 5610 :: 5611 5612 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5613 5614 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5615 Creates a dedicated event loop thread that devices can be 5616 assigned to. This is known as an IOThread. By default device 5617 emulation happens in vCPU threads or the main event loop thread. 5618 This can become a scalability bottleneck. IOThreads allow device 5619 emulation and I/O to run on other host CPUs. 5620 5621 The ``id`` parameter is a unique ID that will be used to 5622 reference this IOThread from ``-device ...,iothread=id``. 5623 Multiple devices can be assigned to an IOThread. Note that not 5624 all devices support an ``iothread`` parameter. 5625 5626 The ``query-iothreads`` QMP command lists IOThreads and reports 5627 their thread IDs so that the user can configure host CPU 5628 pinning/affinity. 5629 5630 IOThreads use an adaptive polling algorithm to reduce event loop 5631 latency. Instead of entering a blocking system call to monitor 5632 file descriptors and then pay the cost of being woken up when an 5633 event occurs, the polling algorithm spins waiting for events for 5634 a short time. The algorithm's default parameters are suitable 5635 for many cases but can be adjusted based on knowledge of the 5636 workload and/or host device latency. 5637 5638 The ``poll-max-ns`` parameter is the maximum number of 5639 nanoseconds to busy wait for events. Polling can be disabled by 5640 setting this value to 0. 5641 5642 The ``poll-grow`` parameter is the multiplier used to increase 5643 the polling time when the algorithm detects it is missing events 5644 due to not polling long enough. 5645 5646 The ``poll-shrink`` parameter is the divisor used to decrease 5647 the polling time when the algorithm detects it is spending too 5648 long polling without encountering events. 5649 5650 The ``aio-max-batch`` parameter is the maximum number of requests 5651 in a batch for the AIO engine, 0 means that the engine will use 5652 its default. 5653 5654 The IOThread parameters can be modified at run-time using the 5655 ``qom-set`` command (where ``iothread1`` is the IOThread's 5656 ``id``): 5657 5658 :: 5659 5660 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5661ERST 5662 5663 5664HXCOMM This is the last statement. Insert new options before this line! 5665 5666#undef DEF 5667#undef DEFHEADING 5668#undef ARCHHEADING 5669
