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 provied 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 " split-wx=on|off (enable TCG split w^x mapping)\n" 186 " tb-size=n (TCG translation block cache size)\n" 187 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 188 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 189SRST 190``-accel name[,prop=value[,...]]`` 191 This is used to enable an accelerator. Depending on the target 192 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 193 default, tcg is used. If there is more than one accelerator 194 specified, the next one is used if the previous one fails to 195 initialize. 196 197 ``igd-passthru=on|off`` 198 When Xen is in use, this option controls whether Intel 199 integrated graphics devices can be passed through to the guest 200 (default=off) 201 202 ``kernel-irqchip=on|off|split`` 203 Controls KVM in-kernel irqchip support. The default is full 204 acceleration of the interrupt controllers. On x86, split irqchip 205 reduces the kernel attack surface, at a performance cost for 206 non-MSI interrupts. Disabling the in-kernel irqchip completely 207 is not recommended except for debugging purposes. 208 209 ``kvm-shadow-mem=size`` 210 Defines the size of the KVM shadow MMU. 211 212 ``split-wx=on|off`` 213 Controls the use of split w^x mapping for the TCG code generation 214 buffer. Some operating systems require this to be enabled, and in 215 such a case this will default on. On other operating systems, this 216 will default off, but one may enable this for testing or debugging. 217 218 ``tb-size=n`` 219 Controls the size (in MiB) of the TCG translation block cache. 220 221 ``thread=single|multi`` 222 Controls number of TCG threads. When the TCG is multi-threaded 223 there will be one thread per vCPU therefore taking advantage of 224 additional host cores. The default is to enable multi-threading 225 where both the back-end and front-ends support it and no 226 incompatible TCG features have been enabled (e.g. 227 icount/replay). 228 229 ``dirty-ring-size=n`` 230 When the KVM accelerator is used, it controls the size of the per-vCPU 231 dirty page ring buffer (number of entries for each vCPU). It should 232 be a value that is power of two, and it should be 1024 or bigger (but 233 still less than the maximum value that the kernel supports). 4096 234 could be a good initial value if you have no idea which is the best. 235 Set this value to 0 to disable the feature. By default, this feature 236 is disabled (dirty-ring-size=0). When enabled, KVM will instead 237 record dirty pages in a bitmap. 238 239ERST 240 241DEF("smp", HAS_ARG, QEMU_OPTION_smp, 242 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 243 " set the number of initial CPUs to 'n' [default=1]\n" 244 " maxcpus= maximum number of total CPUs, including\n" 245 " offline CPUs for hotplug, etc\n" 246 " sockets= number of sockets on the machine board\n" 247 " dies= number of dies in one socket\n" 248 " clusters= number of clusters in one die\n" 249 " cores= number of cores in one cluster\n" 250 " threads= number of threads in one core\n" 251 "Note: Different machines may have different subsets of the CPU topology\n" 252 " parameters supported, so the actual meaning of the supported parameters\n" 253 " will vary accordingly. For example, for a machine type that supports a\n" 254 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 255 " sequentially mean as below:\n" 256 " sockets means the number of sockets on the machine board\n" 257 " cores means the number of cores in one socket\n" 258 " threads means the number of threads in one core\n" 259 " For a particular machine type board, an expected CPU topology hierarchy\n" 260 " can be defined through the supported sub-option. Unsupported parameters\n" 261 " can also be provided in addition to the sub-option, but their values\n" 262 " must be set as 1 in the purpose of correct parsing.\n", 263 QEMU_ARCH_ALL) 264SRST 265``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 266 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 267 the machine type board. On boards supporting CPU hotplug, the optional 268 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 269 added at runtime. When both parameters are omitted, the maximum number 270 of CPUs will be calculated from the provided topology members and the 271 initial CPU count will match the maximum number. When only one of them 272 is given then the omitted one will be set to its counterpart's value. 273 Both parameters may be specified, but the maximum number of CPUs must 274 be equal to or greater than the initial CPU count. Product of the 275 CPU topology hierarchy must be equal to the maximum number of CPUs. 276 Both parameters are subject to an upper limit that is determined by 277 the specific machine type chosen. 278 279 To control reporting of CPU topology information, values of the topology 280 parameters can be specified. Machines may only support a subset of the 281 parameters and different machines may have different subsets supported 282 which vary depending on capacity of the corresponding CPU targets. So 283 for a particular machine type board, an expected topology hierarchy can 284 be defined through the supported sub-option. Unsupported parameters can 285 also be provided in addition to the sub-option, but their values must be 286 set as 1 in the purpose of correct parsing. 287 288 Either the initial CPU count, or at least one of the topology parameters 289 must be specified. The specified parameters must be greater than zero, 290 explicit configuration like "cpus=0" is not allowed. Values for any 291 omitted parameters will be computed from those which are given. 292 293 For example, the following sub-option defines a CPU topology hierarchy 294 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 295 core) for a machine that only supports sockets/cores/threads. 296 Some members of the option can be omitted but their values will be 297 automatically computed: 298 299 :: 300 301 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 302 303 The following sub-option defines a CPU topology hierarchy (2 sockets 304 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 305 per core) for PC machines which support sockets/dies/cores/threads. 306 Some members of the option can be omitted but their values will be 307 automatically computed: 308 309 :: 310 311 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 312 313 The following sub-option defines a CPU topology hierarchy (2 sockets 314 totally on the machine, 2 clusters per socket, 2 cores per cluster, 315 2 threads per core) for ARM virt machines which support sockets/clusters 316 /cores/threads. Some members of the option can be omitted but their values 317 will be automatically computed: 318 319 :: 320 321 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 322 323 Historically preference was given to the coarsest topology parameters 324 when computing missing values (ie sockets preferred over cores, which 325 were preferred over threads), however, this behaviour is considered 326 liable to change. Prior to 6.2 the preference was sockets over cores 327 over threads. Since 6.2 the preference is cores over sockets over threads. 328 329 For example, the following option defines a machine board with 2 sockets 330 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 331 332 :: 333 334 -smp 2 335ERST 336 337DEF("numa", HAS_ARG, QEMU_OPTION_numa, 338 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 339 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 340 "-numa dist,src=source,dst=destination,val=distance\n" 341 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 342 "-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" 343 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 344 QEMU_ARCH_ALL) 345SRST 346``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 347 \ 348``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 349 \ 350``-numa dist,src=source,dst=destination,val=distance`` 351 \ 352``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 353 \ 354``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 355 \ 356``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 357 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 358 distance from a source node to a destination node. Set the ACPI 359 Heterogeneous Memory Attributes for the given nodes. 360 361 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 362 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 363 contiguous range of CPU indexes (or a single VCPU if lastcpu is 364 omitted). A non-contiguous set of VCPUs can be represented by 365 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 366 omitted on all nodes, VCPUs are automatically split between them. 367 368 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 369 NUMA node: 370 371 :: 372 373 -numa node,cpus=0-2,cpus=5 374 375 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 376 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 377 assign CPU objects to a node using topology layout properties of 378 CPU. The set of properties is machine specific, and depends on used 379 machine type/'\ ``smp``\ ' options. It could be queried with 380 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 381 property specifies node to which CPU object will be assigned, it's 382 required for node to be declared with '\ ``node``\ ' option before 383 it's used with '\ ``cpu``\ ' option. 384 385 For example: 386 387 :: 388 389 -M pc \ 390 -smp 1,sockets=2,maxcpus=2 \ 391 -numa node,nodeid=0 -numa node,nodeid=1 \ 392 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 393 394 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 395 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 396 a given memory backend device to a node. If '\ ``mem``\ ' and 397 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 398 399 400 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 401 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 402 use it. 403 404 '\ ``initiator``\ ' is an additional option that points to an 405 initiator NUMA node that has best performance (the lowest latency or 406 largest bandwidth) to this NUMA node. Note that this option can be 407 set only when the machine property 'hmat' is set to 'on'. 408 409 Following example creates a machine with 2 NUMA nodes, node 0 has 410 CPU. node 1 has only memory, and its initiator is node 0. Note that 411 because node 0 has CPU, by default the initiator of node 0 is itself 412 and must be itself. 413 414 :: 415 416 -machine hmat=on \ 417 -m 2G,slots=2,maxmem=4G \ 418 -object memory-backend-ram,size=1G,id=m0 \ 419 -object memory-backend-ram,size=1G,id=m1 \ 420 -numa node,nodeid=0,memdev=m0 \ 421 -numa node,nodeid=1,memdev=m1,initiator=0 \ 422 -smp 2,sockets=2,maxcpus=2 \ 423 -numa cpu,node-id=0,socket-id=0 \ 424 -numa cpu,node-id=0,socket-id=1 425 426 source and destination are NUMA node IDs. distance is the NUMA 427 distance from source to destination. The distance from a node to 428 itself is always 10. If any pair of nodes is given a distance, then 429 all pairs must be given distances. Although, when distances are only 430 given in one direction for each pair of nodes, then the distances in 431 the opposite directions are assumed to be the same. If, however, an 432 asymmetrical pair of distances is given for even one node pair, then 433 all node pairs must be provided distance values for both directions, 434 even when they are symmetrical. When a node is unreachable from 435 another node, set the pair's distance to 255. 436 437 Note that the -``numa`` option doesn't allocate any of the specified 438 resources, it just assigns existing resources to NUMA nodes. This 439 means that one still has to use the ``-m``, ``-smp`` options to 440 allocate RAM and VCPUs respectively. 441 442 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 443 Information between initiator and target NUMA nodes in ACPI 444 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 445 create memory requests, usually it has one or more processors. 446 Target NUMA node contains addressable memory. 447 448 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 449 the memory hierarchy of the target NUMA node: if hierarchy is 450 'memory', the structure represents the memory performance; if 451 hierarchy is 'first-level\|second-level\|third-level', this 452 structure represents aggregated performance of memory side caches 453 for each domain. type of 'data-type' is type of data represented by 454 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 455 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 456 the target memory; if 'hierarchy' is 457 'first-level\|second-level\|third-level', 'data-type' is 458 'access\|read\|write' hit latency or 'access\|read\|write' hit 459 bandwidth of the target memory side cache. 460 461 lat is latency value in nanoseconds. bw is bandwidth value, the 462 possible value and units are NUM[M\|G\|T], mean that the bandwidth 463 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 464 used suffix). Note that if latency or bandwidth value is 0, means 465 the corresponding latency or bandwidth information is not provided. 466 467 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 468 belongs. size is the size of memory side cache in bytes. level is 469 the cache level described in this structure, note that the cache 470 level 0 should not be used with '\ ``hmat-cache``\ ' option. 471 associativity is the cache associativity, the possible value is 472 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 473 is the write policy. line is the cache Line size in bytes. 474 475 For example, the following options describe 2 NUMA nodes. Node 0 has 476 2 cpus and a ram, node 1 has only a ram. The processors in node 0 477 access memory in node 0 with access-latency 5 nanoseconds, 478 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 479 memory in NUMA node 1 with access-latency 10 nanoseconds, 480 access-bandwidth is 100 MB/s. And for memory side cache information, 481 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 482 policy is write-back, the cache Line size is 8 bytes: 483 484 :: 485 486 -machine hmat=on \ 487 -m 2G \ 488 -object memory-backend-ram,size=1G,id=m0 \ 489 -object memory-backend-ram,size=1G,id=m1 \ 490 -smp 2,sockets=2,maxcpus=2 \ 491 -numa node,nodeid=0,memdev=m0 \ 492 -numa node,nodeid=1,memdev=m1,initiator=0 \ 493 -numa cpu,node-id=0,socket-id=0 \ 494 -numa cpu,node-id=0,socket-id=1 \ 495 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 496 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 497 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 498 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 499 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 500 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 501ERST 502 503DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 504 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 505 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 506SRST 507``-add-fd fd=fd,set=set[,opaque=opaque]`` 508 Add a file descriptor to an fd set. Valid options are: 509 510 ``fd=fd`` 511 This option defines the file descriptor of which a duplicate is 512 added to fd set. The file descriptor cannot be stdin, stdout, or 513 stderr. 514 515 ``set=set`` 516 This option defines the ID of the fd set to add the file 517 descriptor to. 518 519 ``opaque=opaque`` 520 This option defines a free-form string that can be used to 521 describe fd. 522 523 You can open an image using pre-opened file descriptors from an fd 524 set: 525 526 .. parsed-literal:: 527 528 |qemu_system| \\ 529 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 530 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 531 -drive file=/dev/fdset/2,index=0,media=disk 532ERST 533 534DEF("set", HAS_ARG, QEMU_OPTION_set, 535 "-set group.id.arg=value\n" 536 " set <arg> parameter for item <id> of type <group>\n" 537 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 538SRST 539``-set group.id.arg=value`` 540 Set parameter arg for item id of type group 541ERST 542 543DEF("global", HAS_ARG, QEMU_OPTION_global, 544 "-global driver.property=value\n" 545 "-global driver=driver,property=property,value=value\n" 546 " set a global default for a driver property\n", 547 QEMU_ARCH_ALL) 548SRST 549``-global driver.prop=value`` 550 \ 551``-global driver=driver,property=property,value=value`` 552 Set default value of driver's property prop to value, e.g.: 553 554 .. parsed-literal:: 555 556 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 557 558 In particular, you can use this to set driver properties for devices 559 which are created automatically by the machine model. To create a 560 device which is not created automatically and set properties on it, 561 use -``device``. 562 563 -global driver.prop=value is shorthand for -global 564 driver=driver,property=prop,value=value. The longhand syntax works 565 even when driver contains a dot. 566ERST 567 568DEF("boot", HAS_ARG, QEMU_OPTION_boot, 569 "-boot [order=drives][,once=drives][,menu=on|off]\n" 570 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 571 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 572 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 573 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 574 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 575 QEMU_ARCH_ALL) 576SRST 577``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 578 Specify boot order drives as a string of drive letters. Valid drive 579 letters depend on the target architecture. The x86 PC uses: a, b 580 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 581 (Etherboot from network adapter 1-4), hard disk boot is the default. 582 To apply a particular boot order only on the first startup, specify 583 it via ``once``. Note that the ``order`` or ``once`` parameter 584 should not be used together with the ``bootindex`` property of 585 devices, since the firmware implementations normally do not support 586 both at the same time. 587 588 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 589 as firmware/BIOS supports them. The default is non-interactive boot. 590 591 A splash picture could be passed to bios, enabling user to show it 592 as logo, when option splash=sp\_name is given and menu=on, If 593 firmware/BIOS supports them. Currently Seabios for X86 system 594 support it. limitation: The splash file could be a jpeg file or a 595 BMP file in 24 BPP format(true color). The resolution should be 596 supported by the SVGA mode, so the recommended is 320x240, 640x480, 597 800x640. 598 599 A timeout could be passed to bios, guest will pause for rb\_timeout 600 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 601 not reboot, qemu passes '-1' to bios by default. Currently Seabios 602 for X86 system support it. 603 604 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 605 it. This only effects when boot priority is changed by bootindex 606 options. The default is non-strict boot. 607 608 .. parsed-literal:: 609 610 # try to boot from network first, then from hard disk 611 |qemu_system_x86| -boot order=nc 612 # boot from CD-ROM first, switch back to default order after reboot 613 |qemu_system_x86| -boot once=d 614 # boot with a splash picture for 5 seconds. 615 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 616 617 Note: The legacy format '-boot drives' is still supported but its 618 use is discouraged as it may be removed from future versions. 619ERST 620 621DEF("m", HAS_ARG, QEMU_OPTION_m, 622 "-m [size=]megs[,slots=n,maxmem=size]\n" 623 " configure guest RAM\n" 624 " size: initial amount of guest memory\n" 625 " slots: number of hotplug slots (default: none)\n" 626 " maxmem: maximum amount of guest memory (default: none)\n" 627 "NOTE: Some architectures might enforce a specific granularity\n", 628 QEMU_ARCH_ALL) 629SRST 630``-m [size=]megs[,slots=n,maxmem=size]`` 631 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 632 Optionally, a suffix of "M" or "G" can be used to signify a value in 633 megabytes or gigabytes respectively. Optional pair slots, maxmem 634 could be used to set amount of hotpluggable memory slots and maximum 635 amount of memory. Note that maxmem must be aligned to the page size. 636 637 For example, the following command-line sets the guest startup RAM 638 size to 1GB, creates 3 slots to hotplug additional memory and sets 639 the maximum memory the guest can reach to 4GB: 640 641 .. parsed-literal:: 642 643 |qemu_system| -m 1G,slots=3,maxmem=4G 644 645 If slots and maxmem are not specified, memory hotplug won't be 646 enabled and the guest startup RAM will never increase. 647ERST 648 649DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 650 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 651SRST 652``-mem-path path`` 653 Allocate guest RAM from a temporarily created file in path. 654ERST 655 656DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 657 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 658 QEMU_ARCH_ALL) 659SRST 660``-mem-prealloc`` 661 Preallocate memory when using -mem-path. 662ERST 663 664DEF("k", HAS_ARG, QEMU_OPTION_k, 665 "-k language use keyboard layout (for example 'fr' for French)\n", 666 QEMU_ARCH_ALL) 667SRST 668``-k language`` 669 Use keyboard layout language (for example ``fr`` for French). This 670 option is only needed where it is not easy to get raw PC keycodes 671 (e.g. on Macs, with some X11 servers or with a VNC or curses 672 display). You don't normally need to use it on PC/Linux or 673 PC/Windows hosts. 674 675 The available layouts are: 676 677 :: 678 679 ar de-ch es fo fr-ca hu ja mk no pt-br sv 680 da en-gb et fr fr-ch is lt nl pl ru th 681 de en-us fi fr-be hr it lv nl-be pt sl tr 682 683 The default is ``en-us``. 684ERST 685 686 687HXCOMM Deprecated by -audiodev 688DEF("audio-help", 0, QEMU_OPTION_audio_help, 689 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 690 QEMU_ARCH_ALL) 691SRST 692``-audio-help`` 693 Will show the -audiodev equivalent of the currently specified 694 (deprecated) environment variables. 695ERST 696 697DEF("audio", HAS_ARG, QEMU_OPTION_audio, 698 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 699 " specifies the audio backend and device to use;\n" 700 " apart from 'model', options are the same as for -audiodev.\n" 701 " use '-audio model=help' to show possible devices.\n", 702 QEMU_ARCH_ALL) 703SRST 704``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 705 This option is a shortcut for configuring both the guest audio 706 hardware and the host audio backend in one go. 707 The host backend options are the same as with the corresponding 708 ``-audiodev`` options below. The guest hardware model can be set with 709 ``model=modelname``. Use ``model=help`` to list the available device 710 types. 711 712 The following two example do exactly the same, to show how ``-audio`` 713 can be used to shorten the command line length: 714 715 .. parsed-literal:: 716 717 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 718 |qemu_system| -audio pa,model=sb16 719ERST 720 721DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 722 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 723 " specifies the audio backend to use\n" 724 " id= identifier of the backend\n" 725 " timer-period= timer period in microseconds\n" 726 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 727 " in|out.fixed-settings= use fixed settings for host audio\n" 728 " in|out.frequency= frequency to use with fixed settings\n" 729 " in|out.channels= number of channels to use with fixed settings\n" 730 " in|out.format= sample format to use with fixed settings\n" 731 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 732 " in|out.voices= number of voices to use\n" 733 " in|out.buffer-length= length of buffer in microseconds\n" 734 "-audiodev none,id=id,[,prop[=value][,...]]\n" 735 " dummy driver that discards all output\n" 736#ifdef CONFIG_AUDIO_ALSA 737 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 738 " in|out.dev= name of the audio device to use\n" 739 " in|out.period-length= length of period in microseconds\n" 740 " in|out.try-poll= attempt to use poll mode\n" 741 " threshold= threshold (in microseconds) when playback starts\n" 742#endif 743#ifdef CONFIG_AUDIO_COREAUDIO 744 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 745 " in|out.buffer-count= number of buffers\n" 746#endif 747#ifdef CONFIG_AUDIO_DSOUND 748 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 749 " latency= add extra latency to playback in microseconds\n" 750#endif 751#ifdef CONFIG_AUDIO_OSS 752 "-audiodev oss,id=id[,prop[=value][,...]]\n" 753 " in|out.dev= path of the audio device to use\n" 754 " in|out.buffer-count= number of buffers\n" 755 " in|out.try-poll= attempt to use poll mode\n" 756 " try-mmap= try using memory mapped access\n" 757 " exclusive= open device in exclusive mode\n" 758 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 759#endif 760#ifdef CONFIG_AUDIO_PA 761 "-audiodev pa,id=id[,prop[=value][,...]]\n" 762 " server= PulseAudio server address\n" 763 " in|out.name= source/sink device name\n" 764 " in|out.latency= desired latency in microseconds\n" 765#endif 766#ifdef CONFIG_AUDIO_SDL 767 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 768 " in|out.buffer-count= number of buffers\n" 769#endif 770#ifdef CONFIG_SPICE 771 "-audiodev spice,id=id[,prop[=value][,...]]\n" 772#endif 773#ifdef CONFIG_DBUS_DISPLAY 774 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 775#endif 776 "-audiodev wav,id=id[,prop[=value][,...]]\n" 777 " path= path of wav file to record\n", 778 QEMU_ARCH_ALL) 779SRST 780``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 781 Adds a new audio backend driver identified by id. There are global 782 and driver specific properties. Some values can be set differently 783 for input and output, they're marked with ``in|out.``. You can set 784 the input's property with ``in.prop`` and the output's property with 785 ``out.prop``. For example: 786 787 :: 788 789 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 790 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 791 792 NOTE: parameter validation is known to be incomplete, in many cases 793 specifying an invalid option causes QEMU to print an error message 794 and continue emulation without sound. 795 796 Valid global options are: 797 798 ``id=identifier`` 799 Identifies the audio backend. 800 801 ``timer-period=period`` 802 Sets the timer period used by the audio subsystem in 803 microseconds. Default is 10000 (10 ms). 804 805 ``in|out.mixing-engine=on|off`` 806 Use QEMU's mixing engine to mix all streams inside QEMU and 807 convert audio formats when not supported by the backend. When 808 off, fixed-settings must be off too. Note that disabling this 809 option means that the selected backend must support multiple 810 streams and the audio formats used by the virtual cards, 811 otherwise you'll get no sound. It's not recommended to disable 812 this option unless you want to use 5.1 or 7.1 audio, as mixing 813 engine only supports mono and stereo audio. Default is on. 814 815 ``in|out.fixed-settings=on|off`` 816 Use fixed settings for host audio. When off, it will change 817 based on how the guest opens the sound card. In this case you 818 must not specify frequency, channels or format. Default is on. 819 820 ``in|out.frequency=frequency`` 821 Specify the frequency to use when using fixed-settings. Default 822 is 44100Hz. 823 824 ``in|out.channels=channels`` 825 Specify the number of channels to use when using fixed-settings. 826 Default is 2 (stereo). 827 828 ``in|out.format=format`` 829 Specify the sample format to use when using fixed-settings. 830 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 831 ``u32``, ``f32``. Default is ``s16``. 832 833 ``in|out.voices=voices`` 834 Specify the number of voices to use. Default is 1. 835 836 ``in|out.buffer-length=usecs`` 837 Sets the size of the buffer in microseconds. 838 839``-audiodev none,id=id[,prop[=value][,...]]`` 840 Creates a dummy backend that discards all outputs. This backend has 841 no backend specific properties. 842 843``-audiodev alsa,id=id[,prop[=value][,...]]`` 844 Creates backend using the ALSA. This backend is only available on 845 Linux. 846 847 ALSA specific options are: 848 849 ``in|out.dev=device`` 850 Specify the ALSA device to use for input and/or output. Default 851 is ``default``. 852 853 ``in|out.period-length=usecs`` 854 Sets the period length in microseconds. 855 856 ``in|out.try-poll=on|off`` 857 Attempt to use poll mode with the device. Default is on. 858 859 ``threshold=threshold`` 860 Threshold (in microseconds) when playback starts. Default is 0. 861 862``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 863 Creates a backend using Apple's Core Audio. This backend is only 864 available on Mac OS and only supports playback. 865 866 Core Audio specific options are: 867 868 ``in|out.buffer-count=count`` 869 Sets the count of the buffers. 870 871``-audiodev dsound,id=id[,prop[=value][,...]]`` 872 Creates a backend using Microsoft's DirectSound. This backend is 873 only available on Windows and only supports playback. 874 875 DirectSound specific options are: 876 877 ``latency=usecs`` 878 Add extra usecs microseconds latency to playback. Default is 879 10000 (10 ms). 880 881``-audiodev oss,id=id[,prop[=value][,...]]`` 882 Creates a backend using OSS. This backend is available on most 883 Unix-like systems. 884 885 OSS specific options are: 886 887 ``in|out.dev=device`` 888 Specify the file name of the OSS device to use. Default is 889 ``/dev/dsp``. 890 891 ``in|out.buffer-count=count`` 892 Sets the count of the buffers. 893 894 ``in|out.try-poll=on|of`` 895 Attempt to use poll mode with the device. Default is on. 896 897 ``try-mmap=on|off`` 898 Try using memory mapped device access. Default is off. 899 900 ``exclusive=on|off`` 901 Open the device in exclusive mode (vmix won't work in this 902 case). Default is off. 903 904 ``dsp-policy=policy`` 905 Sets the timing policy (between 0 and 10, where smaller number 906 means smaller latency but higher CPU usage). Use -1 to use 907 buffer sizes specified by ``buffer`` and ``buffer-count``. This 908 option is ignored if you do not have OSS 4. Default is 5. 909 910``-audiodev pa,id=id[,prop[=value][,...]]`` 911 Creates a backend using PulseAudio. This backend is available on 912 most systems. 913 914 PulseAudio specific options are: 915 916 ``server=server`` 917 Sets the PulseAudio server to connect to. 918 919 ``in|out.name=sink`` 920 Use the specified source/sink for recording/playback. 921 922 ``in|out.latency=usecs`` 923 Desired latency in microseconds. The PulseAudio server will try 924 to honor this value but actual latencies may be lower or higher. 925 926``-audiodev sdl,id=id[,prop[=value][,...]]`` 927 Creates a backend using SDL. This backend is available on most 928 systems, but you should use your platform's native backend if 929 possible. 930 931 SDL specific options are: 932 933 ``in|out.buffer-count=count`` 934 Sets the count of the buffers. 935 936``-audiodev spice,id=id[,prop[=value][,...]]`` 937 Creates a backend that sends audio through SPICE. This backend 938 requires ``-spice`` and automatically selected in that case, so 939 usually you can ignore this option. This backend has no backend 940 specific properties. 941 942``-audiodev wav,id=id[,prop[=value][,...]]`` 943 Creates a backend that writes audio to a WAV file. 944 945 Backend specific options are: 946 947 ``path=path`` 948 Write recorded audio into the specified file. Default is 949 ``qemu.wav``. 950ERST 951 952DEF("device", HAS_ARG, QEMU_OPTION_device, 953 "-device driver[,prop[=value][,...]]\n" 954 " add device (based on driver)\n" 955 " prop=value,... sets driver properties\n" 956 " use '-device help' to print all possible drivers\n" 957 " use '-device driver,help' to print all possible properties\n", 958 QEMU_ARCH_ALL) 959SRST 960``-device driver[,prop[=value][,...]]`` 961 Add device driver. prop=value sets driver properties. Valid 962 properties depend on the driver. To get help on possible drivers and 963 properties, use ``-device help`` and ``-device driver,help``. 964 965 Some drivers are: 966 967``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 968 Add an IPMI BMC. This is a simulation of a hardware management 969 interface processor that normally sits on a system. It provides a 970 watchdog and the ability to reset and power control the system. You 971 need to connect this to an IPMI interface to make it useful 972 973 The IPMI slave address to use for the BMC. The default is 0x20. This 974 address is the BMC's address on the I2C network of management 975 controllers. If you don't know what this means, it is safe to ignore 976 it. 977 978 ``id=id`` 979 The BMC id for interfaces to use this device. 980 981 ``slave_addr=val`` 982 Define slave address to use for the BMC. The default is 0x20. 983 984 ``sdrfile=file`` 985 file containing raw Sensor Data Records (SDR) data. The default 986 is none. 987 988 ``fruareasize=val`` 989 size of a Field Replaceable Unit (FRU) area. The default is 990 1024. 991 992 ``frudatafile=file`` 993 file containing raw Field Replaceable Unit (FRU) inventory data. 994 The default is none. 995 996 ``guid=uuid`` 997 value for the GUID for the BMC, in standard UUID format. If this 998 is set, get "Get GUID" command to the BMC will return it. 999 Otherwise "Get GUID" will return an error. 1000 1001``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1002 Add a connection to an external IPMI BMC simulator. Instead of 1003 locally emulating the BMC like the above item, instead connect to an 1004 external entity that provides the IPMI services. 1005 1006 A connection is made to an external BMC simulator. If you do this, 1007 it is strongly recommended that you use the "reconnect=" chardev 1008 option to reconnect to the simulator if the connection is lost. Note 1009 that if this is not used carefully, it can be a security issue, as 1010 the interface has the ability to send resets, NMIs, and power off 1011 the VM. It's best if QEMU makes a connection to an external 1012 simulator running on a secure port on localhost, so neither the 1013 simulator nor QEMU is exposed to any outside network. 1014 1015 See the "lanserv/README.vm" file in the OpenIPMI library for more 1016 details on the external interface. 1017 1018``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1019 Add a KCS IPMI interafce on the ISA bus. This also adds a 1020 corresponding ACPI and SMBIOS entries, if appropriate. 1021 1022 ``bmc=id`` 1023 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1024 above. 1025 1026 ``ioport=val`` 1027 Define the I/O address of the interface. The default is 0xca0 1028 for KCS. 1029 1030 ``irq=val`` 1031 Define the interrupt to use. The default is 5. To disable 1032 interrupts, set this to 0. 1033 1034``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1035 Like the KCS interface, but defines a BT interface. The default port 1036 is 0xe4 and the default interrupt is 5. 1037 1038``-device pci-ipmi-kcs,bmc=id`` 1039 Add a KCS IPMI interafce on the PCI bus. 1040 1041 ``bmc=id`` 1042 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1043 1044``-device pci-ipmi-bt,bmc=id`` 1045 Like the KCS interface, but defines a BT interface on the PCI bus. 1046 1047``-device intel-iommu[,option=...]`` 1048 This is only supported by ``-machine q35``, which will enable Intel VT-d 1049 emulation within the guest. It supports below options: 1050 1051 ``intremap=on|off`` (default: auto) 1052 This enables interrupt remapping feature. It's required to enable 1053 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1054 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1055 The default value is "auto", which will be decided by the mode of 1056 kernel-irqchip. 1057 1058 ``caching-mode=on|off`` (default: off) 1059 This enables caching mode for the VT-d emulated device. When 1060 caching-mode is enabled, each guest DMA buffer mapping will generate an 1061 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1062 a synchronous way. It is required for ``-device vfio-pci`` to work 1063 with the VT-d device, because host assigned devices requires to setup 1064 the DMA mapping on the host before guest DMA starts. 1065 1066 ``device-iotlb=on|off`` (default: off) 1067 This enables device-iotlb capability for the emulated VT-d device. So 1068 far virtio/vhost should be the only real user for this parameter, 1069 paired with ats=on configured for the device. 1070 1071 ``aw-bits=39|48`` (default: 39) 1072 This decides the address width of IOVA address space. The address 1073 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1074 4-level IOMMU page tables. 1075 1076 Please also refer to the wiki page for general scenarios of VT-d 1077 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1078 1079ERST 1080 1081DEF("name", HAS_ARG, QEMU_OPTION_name, 1082 "-name string1[,process=string2][,debug-threads=on|off]\n" 1083 " set the name of the guest\n" 1084 " string1 sets the window title and string2 the process name\n" 1085 " When debug-threads is enabled, individual threads are given a separate name\n" 1086 " NOTE: The thread names are for debugging and not a stable API.\n", 1087 QEMU_ARCH_ALL) 1088SRST 1089``-name name`` 1090 Sets the name of the guest. This name will be displayed in the SDL 1091 window caption. The name will also be used for the VNC server. Also 1092 optionally set the top visible process name in Linux. Naming of 1093 individual threads can also be enabled on Linux to aid debugging. 1094ERST 1095 1096DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1097 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1098 " specify machine UUID\n", QEMU_ARCH_ALL) 1099SRST 1100``-uuid uuid`` 1101 Set system UUID. 1102ERST 1103 1104DEFHEADING() 1105 1106DEFHEADING(Block device options:) 1107 1108SRST 1109The QEMU block device handling options have a long history and 1110have gone through several iterations as the feature set and complexity 1111of the block layer have grown. Many online guides to QEMU often 1112reference older and deprecated options, which can lead to confusion. 1113 1114The recommended modern way to describe disks is to use a combination of 1115``-device`` to specify the hardware device and ``-blockdev`` to 1116describe the backend. The device defines what the guest sees and the 1117backend describes how QEMU handles the data. 1118 1119ERST 1120 1121DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1122 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1123DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1124SRST 1125``-fda file`` 1126 \ 1127``-fdb file`` 1128 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1129 the System Emulation Users Guide). 1130ERST 1131 1132DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1133 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1134DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1135DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1136 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1137DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1138SRST 1139``-hda file`` 1140 \ 1141``-hdb file`` 1142 \ 1143``-hdc file`` 1144 \ 1145``-hdd file`` 1146 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1147 chapter in the System Emulation Users Guide). 1148ERST 1149 1150DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1151 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1152 QEMU_ARCH_ALL) 1153SRST 1154``-cdrom file`` 1155 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1156 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1157 as filename. 1158ERST 1159 1160DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1161 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1162 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1163 " [,read-only=on|off][,auto-read-only=on|off]\n" 1164 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1165 " [,driver specific parameters...]\n" 1166 " configure a block backend\n", QEMU_ARCH_ALL) 1167SRST 1168``-blockdev option[,option[,option[,...]]]`` 1169 Define a new block driver node. Some of the options apply to all 1170 block drivers, other options are only accepted for a specific block 1171 driver. See below for a list of generic options and options for the 1172 most common block drivers. 1173 1174 Options that expect a reference to another node (e.g. ``file``) can 1175 be given in two ways. Either you specify the node name of an already 1176 existing node (file=node-name), or you define a new node inline, 1177 adding options for the referenced node after a dot 1178 (file.filename=path,file.aio=native). 1179 1180 A block driver node created with ``-blockdev`` can be used for a 1181 guest device by specifying its node name for the ``drive`` property 1182 in a ``-device`` argument that defines a block device. 1183 1184 ``Valid options for any block driver node:`` 1185 ``driver`` 1186 Specifies the block driver to use for the given node. 1187 1188 ``node-name`` 1189 This defines the name of the block driver node by which it 1190 will be referenced later. The name must be unique, i.e. it 1191 must not match the name of a different block driver node, or 1192 (if you use ``-drive`` as well) the ID of a drive. 1193 1194 If no node name is specified, it is automatically generated. 1195 The generated node name is not intended to be predictable 1196 and changes between QEMU invocations. For the top level, an 1197 explicit node name must be specified. 1198 1199 ``read-only`` 1200 Open the node read-only. Guest write attempts will fail. 1201 1202 Note that some block drivers support only read-only access, 1203 either generally or in certain configurations. In this case, 1204 the default value ``read-only=off`` does not work and the 1205 option must be specified explicitly. 1206 1207 ``auto-read-only`` 1208 If ``auto-read-only=on`` is set, QEMU may fall back to 1209 read-only usage even when ``read-only=off`` is requested, or 1210 even switch between modes as needed, e.g. depending on 1211 whether the image file is writable or whether a writing user 1212 is attached to the node. 1213 1214 ``force-share`` 1215 Override the image locking system of QEMU by forcing the 1216 node to utilize weaker shared access for permissions where 1217 it would normally request exclusive access. When there is 1218 the potential for multiple instances to have the same file 1219 open (whether this invocation of QEMU is the first or the 1220 second instance), both instances must permit shared access 1221 for the second instance to succeed at opening the file. 1222 1223 Enabling ``force-share=on`` requires ``read-only=on``. 1224 1225 ``cache.direct`` 1226 The host page cache can be avoided with ``cache.direct=on``. 1227 This will attempt to do disk IO directly to the guest's 1228 memory. QEMU may still perform an internal copy of the data. 1229 1230 ``cache.no-flush`` 1231 In case you don't care about data integrity over host 1232 failures, you can use ``cache.no-flush=on``. This option 1233 tells QEMU that it never needs to write any data to the disk 1234 but can instead keep things in cache. If anything goes 1235 wrong, like your host losing power, the disk storage getting 1236 disconnected accidentally, etc. your image will most 1237 probably be rendered unusable. 1238 1239 ``discard=discard`` 1240 discard is one of "ignore" (or "off") or "unmap" (or "on") 1241 and controls whether ``discard`` (also known as ``trim`` or 1242 ``unmap``) requests are ignored or passed to the filesystem. 1243 Some machine types may not support discard requests. 1244 1245 ``detect-zeroes=detect-zeroes`` 1246 detect-zeroes is "off", "on" or "unmap" and enables the 1247 automatic conversion of plain zero writes by the OS to 1248 driver specific optimized zero write commands. You may even 1249 choose "unmap" if discard is set to "unmap" to allow a zero 1250 write to be converted to an ``unmap`` operation. 1251 1252 ``Driver-specific options for file`` 1253 This is the protocol-level block driver for accessing regular 1254 files. 1255 1256 ``filename`` 1257 The path to the image file in the local filesystem 1258 1259 ``aio`` 1260 Specifies the AIO backend (threads/native/io_uring, 1261 default: threads) 1262 1263 ``locking`` 1264 Specifies whether the image file is protected with Linux OFD 1265 / POSIX locks. The default is to use the Linux Open File 1266 Descriptor API if available, otherwise no lock is applied. 1267 (auto/on/off, default: auto) 1268 1269 Example: 1270 1271 :: 1272 1273 -blockdev driver=file,node-name=disk,filename=disk.img 1274 1275 ``Driver-specific options for raw`` 1276 This is the image format block driver for raw images. It is 1277 usually stacked on top of a protocol level block driver such as 1278 ``file``. 1279 1280 ``file`` 1281 Reference to or definition of the data source block driver 1282 node (e.g. a ``file`` driver node) 1283 1284 Example 1: 1285 1286 :: 1287 1288 -blockdev driver=file,node-name=disk_file,filename=disk.img 1289 -blockdev driver=raw,node-name=disk,file=disk_file 1290 1291 Example 2: 1292 1293 :: 1294 1295 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1296 1297 ``Driver-specific options for qcow2`` 1298 This is the image format block driver for qcow2 images. It is 1299 usually stacked on top of a protocol level block driver such as 1300 ``file``. 1301 1302 ``file`` 1303 Reference to or definition of the data source block driver 1304 node (e.g. a ``file`` driver node) 1305 1306 ``backing`` 1307 Reference to or definition of the backing file block device 1308 (default is taken from the image file). It is allowed to 1309 pass ``null`` here in order to disable the default backing 1310 file. 1311 1312 ``lazy-refcounts`` 1313 Whether to enable the lazy refcounts feature (on/off; 1314 default is taken from the image file) 1315 1316 ``cache-size`` 1317 The maximum total size of the L2 table and refcount block 1318 caches in bytes (default: the sum of l2-cache-size and 1319 refcount-cache-size) 1320 1321 ``l2-cache-size`` 1322 The maximum size of the L2 table cache in bytes (default: if 1323 cache-size is not specified - 32M on Linux platforms, and 8M 1324 on non-Linux platforms; otherwise, as large as possible 1325 within the cache-size, while permitting the requested or the 1326 minimal refcount cache size) 1327 1328 ``refcount-cache-size`` 1329 The maximum size of the refcount block cache in bytes 1330 (default: 4 times the cluster size; or if cache-size is 1331 specified, the part of it which is not used for the L2 1332 cache) 1333 1334 ``cache-clean-interval`` 1335 Clean unused entries in the L2 and refcount caches. The 1336 interval is in seconds. The default value is 600 on 1337 supporting platforms, and 0 on other platforms. Setting it 1338 to 0 disables this feature. 1339 1340 ``pass-discard-request`` 1341 Whether discard requests to the qcow2 device should be 1342 forwarded to the data source (on/off; default: on if 1343 discard=unmap is specified, off otherwise) 1344 1345 ``pass-discard-snapshot`` 1346 Whether discard requests for the data source should be 1347 issued when a snapshot operation (e.g. deleting a snapshot) 1348 frees clusters in the qcow2 file (on/off; default: on) 1349 1350 ``pass-discard-other`` 1351 Whether discard requests for the data source should be 1352 issued on other occasions where a cluster gets freed 1353 (on/off; default: off) 1354 1355 ``overlap-check`` 1356 Which overlap checks to perform for writes to the image 1357 (none/constant/cached/all; default: cached). For details or 1358 finer granularity control refer to the QAPI documentation of 1359 ``blockdev-add``. 1360 1361 Example 1: 1362 1363 :: 1364 1365 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1366 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1367 1368 Example 2: 1369 1370 :: 1371 1372 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1373 1374 ``Driver-specific options for other drivers`` 1375 Please refer to the QAPI documentation of the ``blockdev-add`` 1376 QMP command. 1377ERST 1378 1379DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1380 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1381 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1382 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1383 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1384 " [,aio=threads|native|io_uring]\n" 1385 " [,readonly=on|off][,copy-on-read=on|off]\n" 1386 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1387 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1388 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1389 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1390 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1391 " [[,iops_size=is]]\n" 1392 " [[,group=g]]\n" 1393 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1394SRST 1395``-drive option[,option[,option[,...]]]`` 1396 Define a new drive. This includes creating a block driver node (the 1397 backend) as well as a guest device, and is mostly a shortcut for 1398 defining the corresponding ``-blockdev`` and ``-device`` options. 1399 1400 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1401 In addition, it knows the following options: 1402 1403 ``file=file`` 1404 This option defines which disk image (see the :ref:`disk images` 1405 chapter in the System Emulation Users Guide) to use with this drive. 1406 If the filename contains comma, you must double it (for instance, 1407 "file=my,,file" to use file "my,file"). 1408 1409 Special files such as iSCSI devices can be specified using 1410 protocol specific URLs. See the section for "Device URL Syntax" 1411 for more information. 1412 1413 ``if=interface`` 1414 This option defines on which type on interface the drive is 1415 connected. Available types are: ide, scsi, sd, mtd, floppy, 1416 pflash, virtio, none. 1417 1418 ``bus=bus,unit=unit`` 1419 These options define where is connected the drive by defining 1420 the bus number and the unit id. 1421 1422 ``index=index`` 1423 This option defines where the drive is connected by using an 1424 index in the list of available connectors of a given interface 1425 type. 1426 1427 ``media=media`` 1428 This option defines the type of the media: disk or cdrom. 1429 1430 ``snapshot=snapshot`` 1431 snapshot is "on" or "off" and controls snapshot mode for the 1432 given drive (see ``-snapshot``). 1433 1434 ``cache=cache`` 1435 cache is "none", "writeback", "unsafe", "directsync" or 1436 "writethrough" and controls how the host cache is used to access 1437 block data. This is a shortcut that sets the ``cache.direct`` 1438 and ``cache.no-flush`` options (as in ``-blockdev``), and 1439 additionally ``cache.writeback``, which provides a default for 1440 the ``write-cache`` option of block guest devices (as in 1441 ``-device``). The modes correspond to the following settings: 1442 1443 ============= =============== ============ ============== 1444 \ cache.writeback cache.direct cache.no-flush 1445 ============= =============== ============ ============== 1446 writeback on off off 1447 none on on off 1448 writethrough off off off 1449 directsync off on off 1450 unsafe on off on 1451 ============= =============== ============ ============== 1452 1453 The default mode is ``cache=writeback``. 1454 1455 ``aio=aio`` 1456 aio is "threads", "native", or "io_uring" and selects between pthread 1457 based disk I/O, native Linux AIO, or Linux io_uring API. 1458 1459 ``format=format`` 1460 Specify which disk format will be used rather than detecting the 1461 format. Can be used to specify format=raw to avoid interpreting 1462 an untrusted format header. 1463 1464 ``werror=action,rerror=action`` 1465 Specify which action to take on write and read errors. Valid 1466 actions are: "ignore" (ignore the error and try to continue), 1467 "stop" (pause QEMU), "report" (report the error to the guest), 1468 "enospc" (pause QEMU only if the host disk is full; report the 1469 error to the guest otherwise). The default setting is 1470 ``werror=enospc`` and ``rerror=report``. 1471 1472 ``copy-on-read=copy-on-read`` 1473 copy-on-read is "on" or "off" and enables whether to copy read 1474 backing file sectors into the image file. 1475 1476 ``bps=b,bps_rd=r,bps_wr=w`` 1477 Specify bandwidth throttling limits in bytes per second, either 1478 for all request types or for reads or writes only. Small values 1479 can lead to timeouts or hangs inside the guest. A safe minimum 1480 for disks is 2 MB/s. 1481 1482 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1483 Specify bursts in bytes per second, either for all request types 1484 or for reads or writes only. Bursts allow the guest I/O to spike 1485 above the limit temporarily. 1486 1487 ``iops=i,iops_rd=r,iops_wr=w`` 1488 Specify request rate limits in requests per second, either for 1489 all request types or for reads or writes only. 1490 1491 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1492 Specify bursts in requests per second, either for all request 1493 types or for reads or writes only. Bursts allow the guest I/O to 1494 spike above the limit temporarily. 1495 1496 ``iops_size=is`` 1497 Let every is bytes of a request count as a new request for iops 1498 throttling purposes. Use this option to prevent guests from 1499 circumventing iops limits by sending fewer but larger requests. 1500 1501 ``group=g`` 1502 Join a throttling quota group with given name g. All drives that 1503 are members of the same group are accounted for together. Use 1504 this option to prevent guests from circumventing throttling 1505 limits by using many small disks instead of a single larger 1506 disk. 1507 1508 By default, the ``cache.writeback=on`` mode is used. It will report 1509 data writes as completed as soon as the data is present in the host 1510 page cache. This is safe as long as your guest OS makes sure to 1511 correctly flush disk caches where needed. If your guest OS does not 1512 handle volatile disk write caches correctly and your host crashes or 1513 loses power, then the guest may experience data corruption. 1514 1515 For such guests, you should consider using ``cache.writeback=off``. 1516 This means that the host page cache will be used to read and write 1517 data, but write notification will be sent to the guest only after 1518 QEMU has made sure to flush each write to the disk. Be aware that 1519 this has a major impact on performance. 1520 1521 When using the ``-snapshot`` option, unsafe caching is always used. 1522 1523 Copy-on-read avoids accessing the same backing file sectors 1524 repeatedly and is useful when the backing file is over a slow 1525 network. By default copy-on-read is off. 1526 1527 Instead of ``-cdrom`` you can use: 1528 1529 .. parsed-literal:: 1530 1531 |qemu_system| -drive file=file,index=2,media=cdrom 1532 1533 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1534 1535 .. parsed-literal:: 1536 1537 |qemu_system| -drive file=file,index=0,media=disk 1538 |qemu_system| -drive file=file,index=1,media=disk 1539 |qemu_system| -drive file=file,index=2,media=disk 1540 |qemu_system| -drive file=file,index=3,media=disk 1541 1542 You can open an image using pre-opened file descriptors from an fd 1543 set: 1544 1545 .. parsed-literal:: 1546 1547 |qemu_system| \\ 1548 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1549 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1550 -drive file=/dev/fdset/2,index=0,media=disk 1551 1552 You can connect a CDROM to the slave of ide0: 1553 1554 .. parsed-literal:: 1555 1556 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1557 1558 If you don't specify the "file=" argument, you define an empty 1559 drive: 1560 1561 .. parsed-literal:: 1562 1563 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1564 1565 Instead of ``-fda``, ``-fdb``, you can use: 1566 1567 .. parsed-literal:: 1568 1569 |qemu_system_x86| -drive file=file,index=0,if=floppy 1570 |qemu_system_x86| -drive file=file,index=1,if=floppy 1571 1572 By default, interface is "ide" and index is automatically 1573 incremented: 1574 1575 .. parsed-literal:: 1576 1577 |qemu_system_x86| -drive file=a -drive file=b" 1578 1579 is interpreted like: 1580 1581 .. parsed-literal:: 1582 1583 |qemu_system_x86| -hda a -hdb b 1584ERST 1585 1586DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1587 "-mtdblock file use 'file' as on-board Flash memory image\n", 1588 QEMU_ARCH_ALL) 1589SRST 1590``-mtdblock file`` 1591 Use file as on-board Flash memory image. 1592ERST 1593 1594DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1595 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1596SRST 1597``-sd file`` 1598 Use file as SecureDigital card image. 1599ERST 1600 1601DEF("snapshot", 0, QEMU_OPTION_snapshot, 1602 "-snapshot write to temporary files instead of disk image files\n", 1603 QEMU_ARCH_ALL) 1604SRST 1605``-snapshot`` 1606 Write to temporary files instead of disk image files. In this case, 1607 the raw disk image you use is not written back. You can however 1608 force the write back by pressing C-a s (see the :ref:`disk images` 1609 chapter in the System Emulation Users Guide). 1610ERST 1611 1612DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1613 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1614 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1615 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1616 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1617 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1618 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1619 " [[,throttling.iops-size=is]]\n" 1620 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1621 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1622 "-fsdev synth,id=id\n", 1623 QEMU_ARCH_ALL) 1624 1625SRST 1626``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1627 \ 1628``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1629 \ 1630``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1631 \ 1632``-fsdev synth,id=id[,readonly=on]`` 1633 Define a new file system device. Valid options are: 1634 1635 ``local`` 1636 Accesses to the filesystem are done by QEMU. 1637 1638 ``proxy`` 1639 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1640 1641 ``synth`` 1642 Synthetic filesystem, only used by QTests. 1643 1644 ``id=id`` 1645 Specifies identifier for this device. 1646 1647 ``path=path`` 1648 Specifies the export path for the file system device. Files 1649 under this path will be available to the 9p client on the guest. 1650 1651 ``security_model=security_model`` 1652 Specifies the security model to be used for this export path. 1653 Supported security models are "passthrough", "mapped-xattr", 1654 "mapped-file" and "none". In "passthrough" security model, files 1655 are stored using the same credentials as they are created on the 1656 guest. This requires QEMU to run as root. In "mapped-xattr" 1657 security model, some of the file attributes like uid, gid, mode 1658 bits and link target are stored as file attributes. For 1659 "mapped-file" these attributes are stored in the hidden 1660 .virtfs\_metadata directory. Directories exported by this 1661 security model cannot interact with other unix tools. "none" 1662 security model is same as passthrough except the sever won't 1663 report failures if it fails to set file attributes like 1664 ownership. Security model is mandatory only for local fsdriver. 1665 Other fsdrivers (like proxy) don't take security model as a 1666 parameter. 1667 1668 ``writeout=writeout`` 1669 This is an optional argument. The only supported value is 1670 "immediate". This means that host page cache will be used to 1671 read and write data but write notification will be sent to the 1672 guest only when the data has been reported as written by the 1673 storage subsystem. 1674 1675 ``readonly=on`` 1676 Enables exporting 9p share as a readonly mount for guests. By 1677 default read-write access is given. 1678 1679 ``socket=socket`` 1680 Enables proxy filesystem driver to use passed socket file for 1681 communicating with virtfs-proxy-helper(1). 1682 1683 ``sock_fd=sock_fd`` 1684 Enables proxy filesystem driver to use passed socket descriptor 1685 for communicating with virtfs-proxy-helper(1). Usually a helper 1686 like libvirt will create socketpair and pass one of the fds as 1687 sock\_fd. 1688 1689 ``fmode=fmode`` 1690 Specifies the default mode for newly created files on the host. 1691 Works only with security models "mapped-xattr" and 1692 "mapped-file". 1693 1694 ``dmode=dmode`` 1695 Specifies the default mode for newly created directories on the 1696 host. Works only with security models "mapped-xattr" and 1697 "mapped-file". 1698 1699 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1700 Specify bandwidth throttling limits in bytes per second, either 1701 for all request types or for reads or writes only. 1702 1703 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1704 Specify bursts in bytes per second, either for all request types 1705 or for reads or writes only. Bursts allow the guest I/O to spike 1706 above the limit temporarily. 1707 1708 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1709 Specify request rate limits in requests per second, either for 1710 all request types or for reads or writes only. 1711 1712 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1713 Specify bursts in requests per second, either for all request 1714 types or for reads or writes only. Bursts allow the guest I/O to 1715 spike above the limit temporarily. 1716 1717 ``throttling.iops-size=is`` 1718 Let every is bytes of a request count as a new request for iops 1719 throttling purposes. 1720 1721 -fsdev option is used along with -device driver "virtio-9p-...". 1722 1723``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1724 Options for virtio-9p-... driver are: 1725 1726 ``type`` 1727 Specifies the variant to be used. Supported values are "pci", 1728 "ccw" or "device", depending on the machine type. 1729 1730 ``fsdev=id`` 1731 Specifies the id value specified along with -fsdev option. 1732 1733 ``mount_tag=mount_tag`` 1734 Specifies the tag name to be used by the guest to mount this 1735 export point. 1736ERST 1737 1738DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1739 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1740 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1741 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1742 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1743 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1744 QEMU_ARCH_ALL) 1745 1746SRST 1747``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1748 \ 1749``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1750 \ 1751``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1752 \ 1753``-virtfs synth,mount_tag=mount_tag`` 1754 Define a new virtual filesystem device and expose it to the guest using 1755 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1756 directory on host is made directly accessible by guest as a pass-through 1757 file system by using the 9P network protocol for communication between 1758 host and guests, if desired even accessible, shared by several guests 1759 simultaniously. 1760 1761 Note that ``-virtfs`` is actually just a convenience shortcut for its 1762 generalized form ``-fsdev -device virtio-9p-pci``. 1763 1764 The general form of pass-through file system options are: 1765 1766 ``local`` 1767 Accesses to the filesystem are done by QEMU. 1768 1769 ``proxy`` 1770 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1771 1772 ``synth`` 1773 Synthetic filesystem, only used by QTests. 1774 1775 ``id=id`` 1776 Specifies identifier for the filesystem device 1777 1778 ``path=path`` 1779 Specifies the export path for the file system device. Files 1780 under this path will be available to the 9p client on the guest. 1781 1782 ``security_model=security_model`` 1783 Specifies the security model to be used for this export path. 1784 Supported security models are "passthrough", "mapped-xattr", 1785 "mapped-file" and "none". In "passthrough" security model, files 1786 are stored using the same credentials as they are created on the 1787 guest. This requires QEMU to run as root. In "mapped-xattr" 1788 security model, some of the file attributes like uid, gid, mode 1789 bits and link target are stored as file attributes. For 1790 "mapped-file" these attributes are stored in the hidden 1791 .virtfs\_metadata directory. Directories exported by this 1792 security model cannot interact with other unix tools. "none" 1793 security model is same as passthrough except the sever won't 1794 report failures if it fails to set file attributes like 1795 ownership. Security model is mandatory only for local fsdriver. 1796 Other fsdrivers (like proxy) don't take security model as a 1797 parameter. 1798 1799 ``writeout=writeout`` 1800 This is an optional argument. The only supported value is 1801 "immediate". This means that host page cache will be used to 1802 read and write data but write notification will be sent to the 1803 guest only when the data has been reported as written by the 1804 storage subsystem. 1805 1806 ``readonly=on`` 1807 Enables exporting 9p share as a readonly mount for guests. By 1808 default read-write access is given. 1809 1810 ``socket=socket`` 1811 Enables proxy filesystem driver to use passed socket file for 1812 communicating with virtfs-proxy-helper(1). Usually a helper like 1813 libvirt will create socketpair and pass one of the fds as 1814 sock\_fd. 1815 1816 ``sock_fd`` 1817 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1818 socket descriptor for interfacing with virtfs-proxy-helper(1). 1819 1820 ``fmode=fmode`` 1821 Specifies the default mode for newly created files on the host. 1822 Works only with security models "mapped-xattr" and 1823 "mapped-file". 1824 1825 ``dmode=dmode`` 1826 Specifies the default mode for newly created directories on the 1827 host. Works only with security models "mapped-xattr" and 1828 "mapped-file". 1829 1830 ``mount_tag=mount_tag`` 1831 Specifies the tag name to be used by the guest to mount this 1832 export point. 1833 1834 ``multidevs=multidevs`` 1835 Specifies how to deal with multiple devices being shared with a 1836 9p export. Supported behaviours are either "remap", "forbid" or 1837 "warn". The latter is the default behaviour on which virtfs 9p 1838 expects only one device to be shared with the same export, and 1839 if more than one device is shared and accessed via the same 9p 1840 export then only a warning message is logged (once) by qemu on 1841 host side. In order to avoid file ID collisions on guest you 1842 should either create a separate virtfs export for each device to 1843 be shared with guests (recommended way) or you might use "remap" 1844 instead which allows you to share multiple devices with only one 1845 export instead, which is achieved by remapping the original 1846 inode numbers from host to guest in a way that would prevent 1847 such collisions. Remapping inodes in such use cases is required 1848 because the original device IDs from host are never passed and 1849 exposed on guest. Instead all files of an export shared with 1850 virtfs always share the same device id on guest. So two files 1851 with identical inode numbers but from actually different devices 1852 on host would otherwise cause a file ID collision and hence 1853 potential misbehaviours on guest. "forbid" on the other hand 1854 assumes like "warn" that only one device is shared by the same 1855 export, however it will not only log a warning message but also 1856 deny access to additional devices on guest. Note though that 1857 "forbid" does currently not block all possible file access 1858 operations (e.g. readdir() would still return entries from other 1859 devices). 1860ERST 1861 1862DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1863 "-iscsi [user=user][,password=password]\n" 1864 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1865 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1866 " [,timeout=timeout]\n" 1867 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1868 1869SRST 1870``-iscsi`` 1871 Configure iSCSI session parameters. 1872ERST 1873 1874DEFHEADING() 1875 1876DEFHEADING(USB convenience options:) 1877 1878DEF("usb", 0, QEMU_OPTION_usb, 1879 "-usb enable on-board USB host controller (if not enabled by default)\n", 1880 QEMU_ARCH_ALL) 1881SRST 1882``-usb`` 1883 Enable USB emulation on machine types with an on-board USB host 1884 controller (if not enabled by default). Note that on-board USB host 1885 controllers may not support USB 3.0. In this case 1886 ``-device qemu-xhci`` can be used instead on machines with PCI. 1887ERST 1888 1889DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1890 "-usbdevice name add the host or guest USB device 'name'\n", 1891 QEMU_ARCH_ALL) 1892SRST 1893``-usbdevice devname`` 1894 Add the USB device devname, and enable an on-board USB controller 1895 if possible and necessary (just like it can be done via 1896 ``-machine usb=on``). Note that this option is mainly intended for 1897 the user's convenience only. More fine-grained control can be 1898 achieved by selecting a USB host controller (if necessary) and the 1899 desired USB device via the ``-device`` option instead. For example, 1900 instead of using ``-usbdevice mouse`` it is possible to use 1901 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1902 to a USB 3.0 controller instead (at least on machines that support 1903 PCI and do not have an USB controller enabled by default yet). 1904 For more details, see the chapter about 1905 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1906 Possible devices for devname are: 1907 1908 ``braille`` 1909 Braille device. This will use BrlAPI to display the braille 1910 output on a real or fake device (i.e. it also creates a 1911 corresponding ``braille`` chardev automatically beside the 1912 ``usb-braille`` USB device). 1913 1914 ``keyboard`` 1915 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1916 1917 ``mouse`` 1918 Virtual Mouse. This will override the PS/2 mouse emulation when 1919 activated. 1920 1921 ``tablet`` 1922 Pointer device that uses absolute coordinates (like a 1923 touchscreen). This means QEMU is able to report the mouse 1924 position without having to grab the mouse. Also overrides the 1925 PS/2 mouse emulation when activated. 1926 1927 ``wacom-tablet`` 1928 Wacom PenPartner USB tablet. 1929 1930 1931ERST 1932 1933DEFHEADING() 1934 1935DEFHEADING(Display options:) 1936 1937DEF("display", HAS_ARG, QEMU_OPTION_display, 1938#if defined(CONFIG_SPICE) 1939 "-display spice-app[,gl=on|off]\n" 1940#endif 1941#if defined(CONFIG_SDL) 1942 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 1943 " [,window-close=on|off]\n" 1944#endif 1945#if defined(CONFIG_GTK) 1946 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1947 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 1948#endif 1949#if defined(CONFIG_VNC) 1950 "-display vnc=<display>[,<optargs>]\n" 1951#endif 1952#if defined(CONFIG_CURSES) 1953 "-display curses[,charset=<encoding>]\n" 1954#endif 1955#if defined(CONFIG_COCOA) 1956 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 1957#endif 1958#if defined(CONFIG_OPENGL) 1959 "-display egl-headless[,rendernode=<file>]\n" 1960#endif 1961#if defined(CONFIG_DBUS_DISPLAY) 1962 "-display dbus[,addr=<dbusaddr>]\n" 1963 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1964#endif 1965#if defined(CONFIG_COCOA) 1966 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 1967#endif 1968 "-display none\n" 1969 " select display backend type\n" 1970 " The default display is equivalent to\n " 1971#if defined(CONFIG_GTK) 1972 "\"-display gtk\"\n" 1973#elif defined(CONFIG_SDL) 1974 "\"-display sdl\"\n" 1975#elif defined(CONFIG_COCOA) 1976 "\"-display cocoa\"\n" 1977#elif defined(CONFIG_VNC) 1978 "\"-vnc localhost:0,to=99,id=default\"\n" 1979#else 1980 "\"-display none\"\n" 1981#endif 1982 , QEMU_ARCH_ALL) 1983SRST 1984``-display type`` 1985 Select type of display to use. Use ``-display help`` to list the available 1986 display types. Valid values for type are 1987 1988 ``spice-app[,gl=on|off]`` 1989 Start QEMU as a Spice server and launch the default Spice client 1990 application. The Spice server will redirect the serial consoles 1991 and QEMU monitors. (Since 4.0) 1992 1993 ``dbus`` 1994 Export the display over D-Bus interfaces. (Since 7.0) 1995 1996 The connection is registered with the "org.qemu" name (and queued when 1997 already owned). 1998 1999 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2000 2001 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2002 2003 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2004 will share framebuffers with DMABUF file descriptors). 2005 2006 ``sdl`` 2007 Display video output via SDL (usually in a separate graphics 2008 window; see the SDL documentation for other possibilities). 2009 Valid parameters are: 2010 2011 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2012 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2013 either ``lshift-lctrl-lalt`` or ``rctrl``. 2014 2015 ``gl=on|off|core|es`` : Use OpenGL for displaying 2016 2017 ``show-cursor=on|off`` : Force showing the mouse cursor 2018 2019 ``window-close=on|off`` : Allow to quit qemu with window close button 2020 2021 ``gtk`` 2022 Display video output in a GTK window. This interface provides 2023 drop-down menus and other UI elements to configure and control 2024 the VM during runtime. Valid parameters are: 2025 2026 ``full-screen=on|off`` : Start in fullscreen mode 2027 2028 ``gl=on|off`` : Use OpenGL for displaying 2029 2030 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2031 2032 ``show-tabs=on|off`` : Display the tab bar for switching between the 2033 various graphical interfaces (e.g. VGA and 2034 virtual console character devices) by default. 2035 2036 ``show-cursor=on|off`` : Force showing the mouse cursor 2037 2038 ``window-close=on|off`` : Allow to quit qemu with window close button 2039 2040 ``curses[,charset=<encoding>]`` 2041 Display video output via curses. For graphics device models 2042 which support a text mode, QEMU can display this output using a 2043 curses/ncurses interface. Nothing is displayed when the graphics 2044 device is in graphical mode or if the graphics device does not 2045 support a text mode. Generally only the VGA device models 2046 support text mode. The font charset used by the guest can be 2047 specified with the ``charset`` option, for example 2048 ``charset=CP850`` for IBM CP850 encoding. The default is 2049 ``CP437``. 2050 2051 ``cocoa`` 2052 Display video output in a Cocoa window. Mac only. This interface 2053 provides drop-down menus and other UI elements to configure and 2054 control the VM during runtime. Valid parameters are: 2055 2056 ``show-cursor=on|off`` : Force showing the mouse cursor 2057 2058 ``left-command-key=on|off`` : Disable forwarding left command key to host 2059 2060 ``egl-headless[,rendernode=<file>]`` 2061 Offload all OpenGL operations to a local DRI device. For any 2062 graphical display, this display needs to be paired with either 2063 VNC or SPICE displays. 2064 2065 ``vnc=<display>`` 2066 Start a VNC server on display <display> 2067 2068 ``none`` 2069 Do not display video output. The guest will still see an 2070 emulated graphics card, but its output will not be displayed to 2071 the QEMU user. This option differs from the -nographic option in 2072 that it only affects what is done with video output; -nographic 2073 also changes the destination of the serial and parallel port 2074 data. 2075ERST 2076 2077DEF("nographic", 0, QEMU_OPTION_nographic, 2078 "-nographic disable graphical output and redirect serial I/Os to console\n", 2079 QEMU_ARCH_ALL) 2080SRST 2081``-nographic`` 2082 Normally, if QEMU is compiled with graphical window support, it 2083 displays output such as guest graphics, guest console, and the QEMU 2084 monitor in a window. With this option, you can totally disable 2085 graphical output so that QEMU is a simple command line application. 2086 The emulated serial port is redirected on the console and muxed with 2087 the monitor (unless redirected elsewhere explicitly). Therefore, you 2088 can still use QEMU to debug a Linux kernel with a serial console. 2089 Use C-a h for help on switching between the console and monitor. 2090ERST 2091 2092#ifdef CONFIG_SPICE 2093DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2094 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2095 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2096 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2097 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2098 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2099 " [,tls-ciphers=<list>]\n" 2100 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2101 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2102 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2103 " [,password=<string>][,password-secret=<secret-id>]\n" 2104 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2105 " [,jpeg-wan-compression=[auto|never|always]]\n" 2106 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2107 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2108 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2109 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2110 " [,gl=[on|off]][,rendernode=<file>]\n" 2111 " enable spice\n" 2112 " at least one of {port, tls-port} is mandatory\n", 2113 QEMU_ARCH_ALL) 2114#endif 2115SRST 2116``-spice option[,option[,...]]`` 2117 Enable the spice remote desktop protocol. Valid options are 2118 2119 ``port=<nr>`` 2120 Set the TCP port spice is listening on for plaintext channels. 2121 2122 ``addr=<addr>`` 2123 Set the IP address spice is listening on. Default is any 2124 address. 2125 2126 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2127 Force using the specified IP version. 2128 2129 ``password=<string>`` 2130 Set the password you need to authenticate. 2131 2132 This option is deprecated and insecure because it leaves the 2133 password visible in the process listing. Use ``password-secret`` 2134 instead. 2135 2136 ``password-secret=<secret-id>`` 2137 Set the ID of the ``secret`` object containing the password 2138 you need to authenticate. 2139 2140 ``sasl=on|off`` 2141 Require that the client use SASL to authenticate with the spice. 2142 The exact choice of authentication method used is controlled 2143 from the system / user's SASL configuration file for the 'qemu' 2144 service. This is typically found in /etc/sasl2/qemu.conf. If 2145 running QEMU as an unprivileged user, an environment variable 2146 SASL\_CONF\_PATH can be used to make it search alternate 2147 locations for the service config. While some SASL auth methods 2148 can also provide data encryption (eg GSSAPI), it is recommended 2149 that SASL always be combined with the 'tls' and 'x509' settings 2150 to enable use of SSL and server certificates. This ensures a 2151 data encryption preventing compromise of authentication 2152 credentials. 2153 2154 ``disable-ticketing=on|off`` 2155 Allow client connects without authentication. 2156 2157 ``disable-copy-paste=on|off`` 2158 Disable copy paste between the client and the guest. 2159 2160 ``disable-agent-file-xfer=on|off`` 2161 Disable spice-vdagent based file-xfer between the client and the 2162 guest. 2163 2164 ``tls-port=<nr>`` 2165 Set the TCP port spice is listening on for encrypted channels. 2166 2167 ``x509-dir=<dir>`` 2168 Set the x509 file directory. Expects same filenames as -vnc 2169 $display,x509=$dir 2170 2171 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2172 The x509 file names can also be configured individually. 2173 2174 ``tls-ciphers=<list>`` 2175 Specify which ciphers to use. 2176 2177 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2178 Force specific channel to be used with or without TLS 2179 encryption. The options can be specified multiple times to 2180 configure multiple channels. The special name "default" can be 2181 used to set the default mode. For channels which are not 2182 explicitly forced into one mode the spice client is allowed to 2183 pick tls/plaintext as he pleases. 2184 2185 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2186 Configure image compression (lossless). Default is auto\_glz. 2187 2188 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2189 Configure wan image compression (lossy for slow links). Default 2190 is auto. 2191 2192 ``streaming-video=[off|all|filter]`` 2193 Configure video stream detection. Default is off. 2194 2195 ``agent-mouse=[on|off]`` 2196 Enable/disable passing mouse events via vdagent. Default is on. 2197 2198 ``playback-compression=[on|off]`` 2199 Enable/disable audio stream compression (using celt 0.5.1). 2200 Default is on. 2201 2202 ``seamless-migration=[on|off]`` 2203 Enable/disable spice seamless migration. Default is off. 2204 2205 ``gl=[on|off]`` 2206 Enable/disable OpenGL context. Default is off. 2207 2208 ``rendernode=<file>`` 2209 DRM render node for OpenGL rendering. If not specified, it will 2210 pick the first available. (Since 2.9) 2211ERST 2212 2213DEF("portrait", 0, QEMU_OPTION_portrait, 2214 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2215 QEMU_ARCH_ALL) 2216SRST 2217``-portrait`` 2218 Rotate graphical output 90 deg left (only PXA LCD). 2219ERST 2220 2221DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2222 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2223 QEMU_ARCH_ALL) 2224SRST 2225``-rotate deg`` 2226 Rotate graphical output some deg left (only PXA LCD). 2227ERST 2228 2229DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2230 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2231 " select video card type\n", QEMU_ARCH_ALL) 2232SRST 2233``-vga type`` 2234 Select type of VGA card to emulate. Valid values for type are 2235 2236 ``cirrus`` 2237 Cirrus Logic GD5446 Video card. All Windows versions starting 2238 from Windows 95 should recognize and use this graphic card. For 2239 optimal performances, use 16 bit color depth in the guest and 2240 the host OS. (This card was the default before QEMU 2.2) 2241 2242 ``std`` 2243 Standard VGA card with Bochs VBE extensions. If your guest OS 2244 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2245 you want to use high resolution modes (>= 1280x1024x16) then you 2246 should use this option. (This card is the default since QEMU 2247 2.2) 2248 2249 ``vmware`` 2250 VMWare SVGA-II compatible adapter. Use it if you have 2251 sufficiently recent XFree86/XOrg server or Windows guest with a 2252 driver for this card. 2253 2254 ``qxl`` 2255 QXL paravirtual graphic card. It is VGA compatible (including 2256 VESA 2.0 VBE support). Works best with qxl guest drivers 2257 installed though. Recommended choice when using the spice 2258 protocol. 2259 2260 ``tcx`` 2261 (sun4m only) Sun TCX framebuffer. This is the default 2262 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2263 colour depths at a fixed resolution of 1024x768. 2264 2265 ``cg3`` 2266 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2267 framebuffer for sun4m machines available in both 1024x768 2268 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2269 wishing to run older Solaris versions. 2270 2271 ``virtio`` 2272 Virtio VGA card. 2273 2274 ``none`` 2275 Disable VGA card. 2276ERST 2277 2278DEF("full-screen", 0, QEMU_OPTION_full_screen, 2279 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2280SRST 2281``-full-screen`` 2282 Start in full screen. 2283ERST 2284 2285DEF("g", HAS_ARG, QEMU_OPTION_g , 2286 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2287 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2288SRST 2289``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2290 Set the initial graphical resolution and depth (PPC, SPARC only). 2291 2292 For PPC the default is 800x600x32. 2293 2294 For SPARC with the TCX graphics device, the default is 1024x768x8 2295 with the option of 1024x768x24. For cgthree, the default is 2296 1024x768x8 with the option of 1152x900x8 for people who wish to use 2297 OBP. 2298ERST 2299 2300DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2301 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2302SRST 2303``-vnc display[,option[,option[,...]]]`` 2304 Normally, if QEMU is compiled with graphical window support, it 2305 displays output such as guest graphics, guest console, and the QEMU 2306 monitor in a window. With this option, you can have QEMU listen on 2307 VNC display display and redirect the VGA display over the VNC 2308 session. It is very useful to enable the usb tablet device when 2309 using this option (option ``-device usb-tablet``). When using the 2310 VNC display, you must use the ``-k`` parameter to set the keyboard 2311 layout if you are not using en-us. Valid syntax for the display is 2312 2313 ``to=L`` 2314 With this option, QEMU will try next available VNC displays, 2315 until the number L, if the origianlly defined "-vnc display" is 2316 not available, e.g. port 5900+display is already used by another 2317 application. By default, to=0. 2318 2319 ``host:d`` 2320 TCP connections will only be allowed from host on display d. By 2321 convention the TCP port is 5900+d. Optionally, host can be 2322 omitted in which case the server will accept connections from 2323 any host. 2324 2325 ``unix:path`` 2326 Connections will be allowed over UNIX domain sockets where path 2327 is the location of a unix socket to listen for connections on. 2328 2329 ``none`` 2330 VNC is initialized but not started. The monitor ``change`` 2331 command can be used to later start the VNC server. 2332 2333 Following the display value there may be one or more option flags 2334 separated by commas. Valid options are 2335 2336 ``reverse=on|off`` 2337 Connect to a listening VNC client via a "reverse" connection. 2338 The client is specified by the display. For reverse network 2339 connections (host:d,``reverse``), the d argument is a TCP port 2340 number, not a display number. 2341 2342 ``websocket=on|off`` 2343 Opens an additional TCP listening port dedicated to VNC 2344 Websocket connections. If a bare websocket option is given, the 2345 Websocket port is 5700+display. An alternative port can be 2346 specified with the syntax ``websocket``\ =port. 2347 2348 If host is specified connections will only be allowed from this 2349 host. It is possible to control the websocket listen address 2350 independently, using the syntax ``websocket``\ =host:port. 2351 2352 If no TLS credentials are provided, the websocket connection 2353 runs in unencrypted mode. If TLS credentials are provided, the 2354 websocket connection requires encrypted client connections. 2355 2356 ``password=on|off`` 2357 Require that password based authentication is used for client 2358 connections. 2359 2360 The password must be set separately using the ``set_password`` 2361 command in the :ref:`QEMU monitor`. The 2362 syntax to change your password is: 2363 ``set_password <protocol> <password>`` where <protocol> could be 2364 either "vnc" or "spice". 2365 2366 If you would like to change <protocol> password expiration, you 2367 should use ``expire_password <protocol> <expiration-time>`` 2368 where expiration time could be one of the following options: 2369 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2370 make password expire in 60 seconds, or 1335196800 to make 2371 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2372 this date and time). 2373 2374 You can also use keywords "now" or "never" for the expiration 2375 time to allow <protocol> password to expire immediately or never 2376 expire. 2377 2378 ``password-secret=<secret-id>`` 2379 Require that password based authentication is used for client 2380 connections, using the password provided by the ``secret`` 2381 object identified by ``secret-id``. 2382 2383 ``tls-creds=ID`` 2384 Provides the ID of a set of TLS credentials to use to secure the 2385 VNC server. They will apply to both the normal VNC server socket 2386 and the websocket socket (if enabled). Setting TLS credentials 2387 will cause the VNC server socket to enable the VeNCrypt auth 2388 mechanism. The credentials should have been previously created 2389 using the ``-object tls-creds`` argument. 2390 2391 ``tls-authz=ID`` 2392 Provides the ID of the QAuthZ authorization object against which 2393 the client's x509 distinguished name will validated. This object 2394 is only resolved at time of use, so can be deleted and recreated 2395 on the fly while the VNC server is active. If missing, it will 2396 default to denying access. 2397 2398 ``sasl=on|off`` 2399 Require that the client use SASL to authenticate with the VNC 2400 server. The exact choice of authentication method used is 2401 controlled from the system / user's SASL configuration file for 2402 the 'qemu' service. This is typically found in 2403 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2404 an environment variable SASL\_CONF\_PATH can be used to make it 2405 search alternate locations for the service config. While some 2406 SASL auth methods can also provide data encryption (eg GSSAPI), 2407 it is recommended that SASL always be combined with the 'tls' 2408 and 'x509' settings to enable use of SSL and server 2409 certificates. This ensures a data encryption preventing 2410 compromise of authentication credentials. See the 2411 :ref:`VNC security` section in the System Emulation Users Guide 2412 for details on using SASL authentication. 2413 2414 ``sasl-authz=ID`` 2415 Provides the ID of the QAuthZ authorization object against which 2416 the client's SASL username will validated. This object is only 2417 resolved at time of use, so can be deleted and recreated on the 2418 fly while the VNC server is active. If missing, it will default 2419 to denying access. 2420 2421 ``acl=on|off`` 2422 Legacy method for enabling authorization of clients against the 2423 x509 distinguished name and SASL username. It results in the 2424 creation of two ``authz-list`` objects with IDs of 2425 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2426 objects must be configured with the HMP ACL commands. 2427 2428 This option is deprecated and should no longer be used. The new 2429 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2430 2431 ``lossy=on|off`` 2432 Enable lossy compression methods (gradient, JPEG, ...). If this 2433 option is set, VNC client may receive lossy framebuffer updates 2434 depending on its encoding settings. Enabling this option can 2435 save a lot of bandwidth at the expense of quality. 2436 2437 ``non-adaptive=on|off`` 2438 Disable adaptive encodings. Adaptive encodings are enabled by 2439 default. An adaptive encoding will try to detect frequently 2440 updated screen regions, and send updates in these regions using 2441 a lossy encoding (like JPEG). This can be really helpful to save 2442 bandwidth when playing videos. Disabling adaptive encodings 2443 restores the original static behavior of encodings like Tight. 2444 2445 ``share=[allow-exclusive|force-shared|ignore]`` 2446 Set display sharing policy. 'allow-exclusive' allows clients to 2447 ask for exclusive access. As suggested by the rfb spec this is 2448 implemented by dropping other connections. Connecting multiple 2449 clients in parallel requires all clients asking for a shared 2450 session (vncviewer: -shared switch). This is the default. 2451 'force-shared' disables exclusive client access. Useful for 2452 shared desktop sessions, where you don't want someone forgetting 2453 specify -shared disconnect everybody else. 'ignore' completely 2454 ignores the shared flag and allows everybody connect 2455 unconditionally. Doesn't conform to the rfb spec but is 2456 traditional QEMU behavior. 2457 2458 ``key-delay-ms`` 2459 Set keyboard delay, for key down and key up events, in 2460 milliseconds. Default is 10. Keyboards are low-bandwidth 2461 devices, so this slowdown can help the device and guest to keep 2462 up and not lose events in case events are arriving in bulk. 2463 Possible causes for the latter are flaky network connections, or 2464 scripts for automated testing. 2465 2466 ``audiodev=audiodev`` 2467 Use the specified audiodev when the VNC client requests audio 2468 transmission. When not using an -audiodev argument, this option 2469 must be omitted, otherwise is must be present and specify a 2470 valid audiodev. 2471 2472 ``power-control=on|off`` 2473 Permit the remote client to issue shutdown, reboot or reset power 2474 control requests. 2475ERST 2476 2477ARCHHEADING(, QEMU_ARCH_I386) 2478 2479ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2480 2481DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2482 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2483 QEMU_ARCH_I386) 2484SRST 2485``-win2k-hack`` 2486 Use it when installing Windows 2000 to avoid a disk full bug. After 2487 Windows 2000 is installed, you no longer need this option (this 2488 option slows down the IDE transfers). 2489ERST 2490 2491DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2492 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2493 QEMU_ARCH_I386) 2494SRST 2495``-no-fd-bootchk`` 2496 Disable boot signature checking for floppy disks in BIOS. May be 2497 needed to boot from old floppy disks. 2498ERST 2499 2500DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2501 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2502SRST 2503``-no-acpi`` 2504 Disable ACPI (Advanced Configuration and Power Interface) support. 2505 Use it if your guest OS complains about ACPI problems (PC target 2506 machine only). 2507ERST 2508 2509DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2510 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2511SRST 2512``-no-hpet`` 2513 Disable HPET support. 2514ERST 2515 2516DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2517 "-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" 2518 " ACPI table description\n", QEMU_ARCH_I386) 2519SRST 2520``-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]...]`` 2521 Add ACPI table with specified header fields and context from 2522 specified files. For file=, take whole ACPI table from the specified 2523 files, including all ACPI headers (possible overridden by other 2524 options). For data=, only data portion of the table is used, all 2525 header information is specified in the command line. If a SLIC table 2526 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2527 fields will override the same in the RSDT and the FADT (a.k.a. 2528 FACP), in order to ensure the field matches required by the 2529 Microsoft SLIC spec and the ACPI spec. 2530ERST 2531 2532DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2533 "-smbios file=binary\n" 2534 " load SMBIOS entry from binary file\n" 2535 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2536 " [,uefi=on|off]\n" 2537 " specify SMBIOS type 0 fields\n" 2538 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2539 " [,uuid=uuid][,sku=str][,family=str]\n" 2540 " specify SMBIOS type 1 fields\n" 2541 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2542 " [,asset=str][,location=str]\n" 2543 " specify SMBIOS type 2 fields\n" 2544 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2545 " [,sku=str]\n" 2546 " specify SMBIOS type 3 fields\n" 2547 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2548 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2549 " [,processor-id=%d]\n" 2550 " specify SMBIOS type 4 fields\n" 2551 "-smbios type=11[,value=str][,path=filename]\n" 2552 " specify SMBIOS type 11 fields\n" 2553 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2554 " [,asset=str][,part=str][,speed=%d]\n" 2555 " specify SMBIOS type 17 fields\n" 2556 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2557 " specify SMBIOS type 41 fields\n", 2558 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2559SRST 2560``-smbios file=binary`` 2561 Load SMBIOS entry from binary file. 2562 2563``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2564 Specify SMBIOS type 0 fields 2565 2566``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2567 Specify SMBIOS type 1 fields 2568 2569``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2570 Specify SMBIOS type 2 fields 2571 2572``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2573 Specify SMBIOS type 3 fields 2574 2575``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2576 Specify SMBIOS type 4 fields 2577 2578``-smbios type=11[,value=str][,path=filename]`` 2579 Specify SMBIOS type 11 fields 2580 2581 This argument can be repeated multiple times, and values are added in the order they are parsed. 2582 Applications intending to use OEM strings data are encouraged to use their application name as 2583 a prefix for the value string. This facilitates passing information for multiple applications 2584 concurrently. 2585 2586 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2587 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2588 2589 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2590 the SMBIOS table in the order in which they appear. 2591 2592 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2593 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2594 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2595 data set, for example, by specifying the serial ID of a block device. 2596 2597 An example passing three strings is 2598 2599 .. parsed-literal:: 2600 2601 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2602 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2603 path=/some/file/with/oemstringsdata.txt 2604 2605 In the guest OS this is visible with the ``dmidecode`` command 2606 2607 .. parsed-literal:: 2608 2609 $ dmidecode -t 11 2610 Handle 0x0E00, DMI type 11, 5 bytes 2611 OEM Strings 2612 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2613 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2614 String 3: myapp:some extra data 2615 2616 2617``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2618 Specify SMBIOS type 17 fields 2619 2620``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2621 Specify SMBIOS type 41 fields 2622 2623 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2624 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2625 position on the PCI bus. 2626 2627 Here is an example of use: 2628 2629 .. parsed-literal:: 2630 2631 -netdev user,id=internet \\ 2632 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2633 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2634 2635 In the guest OS, the device should then appear as ``eno1``: 2636 2637 ..parsed-literal:: 2638 2639 $ ip -brief l 2640 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2641 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2642 2643 Currently, the PCI device has to be attached to the root bus. 2644 2645ERST 2646 2647DEFHEADING() 2648 2649DEFHEADING(Network options:) 2650 2651DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2652#ifdef CONFIG_SLIRP 2653 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2654 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2655 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2656 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2657 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2658#ifndef _WIN32 2659 "[,smb=dir[,smbserver=addr]]\n" 2660#endif 2661 " configure a user mode network backend with ID 'str',\n" 2662 " its DHCP server and optional services\n" 2663#endif 2664#ifdef _WIN32 2665 "-netdev tap,id=str,ifname=name\n" 2666 " configure a host TAP network backend with ID 'str'\n" 2667#else 2668 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2669 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2670 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2671 " [,poll-us=n]\n" 2672 " configure a host TAP network backend with ID 'str'\n" 2673 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2674 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2675 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2676 " to deconfigure it\n" 2677 " use '[down]script=no' to disable script execution\n" 2678 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2679 " configure it\n" 2680 " use 'fd=h' to connect to an already opened TAP interface\n" 2681 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2682 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2683 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2684 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2685 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2686 " use vhost=on to enable experimental in kernel accelerator\n" 2687 " (only has effect for virtio guests which use MSIX)\n" 2688 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2689 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2690 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2691 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2692 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2693 " spent on busy polling for vhost net\n" 2694 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2695 " configure a host TAP network backend with ID 'str' that is\n" 2696 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2697 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2698#endif 2699#ifdef __linux__ 2700 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2701 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2702 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2703 " [,rxcookie=rxcookie][,offset=offset]\n" 2704 " configure a network backend with ID 'str' connected to\n" 2705 " an Ethernet over L2TPv3 pseudowire.\n" 2706 " Linux kernel 3.3+ as well as most routers can talk\n" 2707 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2708 " VM to a router and even VM to Host. It is a nearly-universal\n" 2709 " standard (RFC3931). Note - this implementation uses static\n" 2710 " pre-configured tunnels (same as the Linux kernel).\n" 2711 " use 'src=' to specify source address\n" 2712 " use 'dst=' to specify destination address\n" 2713 " use 'udp=on' to specify udp encapsulation\n" 2714 " use 'srcport=' to specify source udp port\n" 2715 " use 'dstport=' to specify destination udp port\n" 2716 " use 'ipv6=on' to force v6\n" 2717 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2718 " well as a weak security measure\n" 2719 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2720 " use 'txcookie=0x012345678' to specify a txcookie\n" 2721 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2722 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2723 " use 'pincounter=on' to work around broken counter handling in peer\n" 2724 " use 'offset=X' to add an extra offset between header and data\n" 2725#endif 2726 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2727 " configure a network backend to connect to another network\n" 2728 " using a socket connection\n" 2729 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2730 " configure a network backend to connect to a multicast maddr and port\n" 2731 " use 'localaddr=addr' to specify the host address to send packets from\n" 2732 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2733 " configure a network backend to connect to another network\n" 2734 " using an UDP tunnel\n" 2735#ifdef CONFIG_VDE 2736 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2737 " configure a network backend to connect to port 'n' of a vde switch\n" 2738 " running on host and listening for incoming connections on 'socketpath'.\n" 2739 " Use group 'groupname' and mode 'octalmode' to change default\n" 2740 " ownership and permissions for communication port.\n" 2741#endif 2742#ifdef CONFIG_NETMAP 2743 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2744 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2745 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2746 " netmap device, defaults to '/dev/netmap')\n" 2747#endif 2748#ifdef CONFIG_POSIX 2749 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2750 " configure a vhost-user network, backed by a chardev 'dev'\n" 2751#endif 2752#ifdef __linux__ 2753 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2754 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2755#endif 2756#ifdef CONFIG_VMNET 2757 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2758 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2759 " configure a vmnet network backend in host mode with ID 'str',\n" 2760 " isolate this interface from others with 'isolated',\n" 2761 " configure the address range and choose a subnet mask,\n" 2762 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2763 " vmnet-host interfaces within this isolated network\n" 2764 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2765 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2766 " configure a vmnet network backend in shared mode with ID 'str',\n" 2767 " configure the address range and choose a subnet mask,\n" 2768 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2769 " isolate this interface from others with 'isolated'\n" 2770 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2771 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2772 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2773 " isolate this interface from others with 'isolated'\n" 2774#endif 2775 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2776 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2777DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2778 "-nic [tap|bridge|" 2779#ifdef CONFIG_SLIRP 2780 "user|" 2781#endif 2782#ifdef __linux__ 2783 "l2tpv3|" 2784#endif 2785#ifdef CONFIG_VDE 2786 "vde|" 2787#endif 2788#ifdef CONFIG_NETMAP 2789 "netmap|" 2790#endif 2791#ifdef CONFIG_POSIX 2792 "vhost-user|" 2793#endif 2794#ifdef CONFIG_VMNET 2795 "vmnet-host|vmnet-shared|vmnet-bridged|" 2796#endif 2797 "socket][,option][,...][mac=macaddr]\n" 2798 " initialize an on-board / default host NIC (using MAC address\n" 2799 " macaddr) and connect it to the given host network backend\n" 2800 "-nic none use it alone to have zero network devices (the default is to\n" 2801 " provided a 'user' network connection)\n", 2802 QEMU_ARCH_ALL) 2803DEF("net", HAS_ARG, QEMU_OPTION_net, 2804 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2805 " configure or create an on-board (or machine default) NIC and\n" 2806 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2807 "-net [" 2808#ifdef CONFIG_SLIRP 2809 "user|" 2810#endif 2811 "tap|" 2812 "bridge|" 2813#ifdef CONFIG_VDE 2814 "vde|" 2815#endif 2816#ifdef CONFIG_NETMAP 2817 "netmap|" 2818#endif 2819#ifdef CONFIG_VMNET 2820 "vmnet-host|vmnet-shared|vmnet-bridged|" 2821#endif 2822 "socket][,option][,option][,...]\n" 2823 " old way to initialize a host network interface\n" 2824 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2825SRST 2826``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2827 This option is a shortcut for configuring both the on-board 2828 (default) guest NIC hardware and the host network backend in one go. 2829 The host backend options are the same as with the corresponding 2830 ``-netdev`` options below. The guest NIC model can be set with 2831 ``model=modelname``. Use ``model=help`` to list the available device 2832 types. The hardware MAC address can be set with ``mac=macaddr``. 2833 2834 The following two example do exactly the same, to show how ``-nic`` 2835 can be used to shorten the command line length: 2836 2837 .. parsed-literal:: 2838 2839 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2840 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2841 2842``-nic none`` 2843 Indicate that no network devices should be configured. It is used to 2844 override the default configuration (default NIC with "user" host 2845 network backend) which is activated if no other networking options 2846 are provided. 2847 2848``-netdev user,id=id[,option][,option][,...]`` 2849 Configure user mode host network backend which requires no 2850 administrator privilege to run. Valid options are: 2851 2852 ``id=id`` 2853 Assign symbolic name for use in monitor commands. 2854 2855 ``ipv4=on|off and ipv6=on|off`` 2856 Specify that either IPv4 or IPv6 must be enabled. If neither is 2857 specified both protocols are enabled. 2858 2859 ``net=addr[/mask]`` 2860 Set IP network address the guest will see. Optionally specify 2861 the netmask, either in the form a.b.c.d or as number of valid 2862 top-most bits. Default is 10.0.2.0/24. 2863 2864 ``host=addr`` 2865 Specify the guest-visible address of the host. Default is the 2866 2nd IP in the guest network, i.e. x.x.x.2. 2867 2868 ``ipv6-net=addr[/int]`` 2869 Set IPv6 network address the guest will see (default is 2870 fec0::/64). The network prefix is given in the usual hexadecimal 2871 IPv6 address notation. The prefix size is optional, and is given 2872 as the number of valid top-most bits (default is 64). 2873 2874 ``ipv6-host=addr`` 2875 Specify the guest-visible IPv6 address of the host. Default is 2876 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2877 2878 ``restrict=on|off`` 2879 If this option is enabled, the guest will be isolated, i.e. it 2880 will not be able to contact the host and no guest IP packets 2881 will be routed over the host to the outside. This option does 2882 not affect any explicitly set forwarding rules. 2883 2884 ``hostname=name`` 2885 Specifies the client hostname reported by the built-in DHCP 2886 server. 2887 2888 ``dhcpstart=addr`` 2889 Specify the first of the 16 IPs the built-in DHCP server can 2890 assign. Default is the 15th to 31st IP in the guest network, 2891 i.e. x.x.x.15 to x.x.x.31. 2892 2893 ``dns=addr`` 2894 Specify the guest-visible address of the virtual nameserver. The 2895 address must be different from the host address. Default is the 2896 3rd IP in the guest network, i.e. x.x.x.3. 2897 2898 ``ipv6-dns=addr`` 2899 Specify the guest-visible address of the IPv6 virtual 2900 nameserver. The address must be different from the host address. 2901 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2902 2903 ``dnssearch=domain`` 2904 Provides an entry for the domain-search list sent by the 2905 built-in DHCP server. More than one domain suffix can be 2906 transmitted by specifying this option multiple times. If 2907 supported, this will cause the guest to automatically try to 2908 append the given domain suffix(es) in case a domain name can not 2909 be resolved. 2910 2911 Example: 2912 2913 .. parsed-literal:: 2914 2915 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2916 2917 ``domainname=domain`` 2918 Specifies the client domain name reported by the built-in DHCP 2919 server. 2920 2921 ``tftp=dir`` 2922 When using the user mode network stack, activate a built-in TFTP 2923 server. The files in dir will be exposed as the root of a TFTP 2924 server. The TFTP client on the guest must be configured in 2925 binary mode (use the command ``bin`` of the Unix TFTP client). 2926 2927 ``tftp-server-name=name`` 2928 In BOOTP reply, broadcast name as the "TFTP server name" 2929 (RFC2132 option 66). This can be used to advise the guest to 2930 load boot files or configurations from a different server than 2931 the host address. 2932 2933 ``bootfile=file`` 2934 When using the user mode network stack, broadcast file as the 2935 BOOTP filename. In conjunction with ``tftp``, this can be used 2936 to network boot a guest from a local directory. 2937 2938 Example (using pxelinux): 2939 2940 .. parsed-literal:: 2941 2942 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2943 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2944 2945 ``smb=dir[,smbserver=addr]`` 2946 When using the user mode network stack, activate a built-in SMB 2947 server so that Windows OSes can access to the host files in 2948 ``dir`` transparently. The IP address of the SMB server can be 2949 set to addr. By default the 4th IP in the guest network is used, 2950 i.e. x.x.x.4. 2951 2952 In the guest Windows OS, the line: 2953 2954 :: 2955 2956 10.0.2.4 smbserver 2957 2958 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2959 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2960 NT/2000). 2961 2962 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2963 2964 Note that a SAMBA server must be installed on the host OS. 2965 2966 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2967 Redirect incoming TCP or UDP connections to the host port 2968 hostport to the guest IP address guestaddr on guest port 2969 guestport. If guestaddr is not specified, its value is x.x.x.15 2970 (default first address given by the built-in DHCP server). By 2971 specifying hostaddr, the rule can be bound to a specific host 2972 interface. If no connection type is set, TCP is used. This 2973 option can be given multiple times. 2974 2975 For example, to redirect host X11 connection from screen 1 to 2976 guest screen 0, use the following: 2977 2978 .. parsed-literal:: 2979 2980 # on the host 2981 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2982 # this host xterm should open in the guest X11 server 2983 xterm -display :1 2984 2985 To redirect telnet connections from host port 5555 to telnet 2986 port on the guest, use the following: 2987 2988 .. parsed-literal:: 2989 2990 # on the host 2991 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2992 telnet localhost 5555 2993 2994 Then when you use on the host ``telnet localhost 5555``, you 2995 connect to the guest telnet server. 2996 2997 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2998 Forward guest TCP connections to the IP address server on port 2999 port to the character device dev or to a program executed by 3000 cmd:command which gets spawned for each connection. This option 3001 can be given multiple times. 3002 3003 You can either use a chardev directly and have that one used 3004 throughout QEMU's lifetime, like in the following example: 3005 3006 .. parsed-literal:: 3007 3008 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3009 # the guest accesses it 3010 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3011 3012 Or you can execute a command on every TCP connection established 3013 by the guest, so that QEMU behaves similar to an inetd process 3014 for that virtual server: 3015 3016 .. parsed-literal:: 3017 3018 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3019 # and connect the TCP stream to its stdin/stdout 3020 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3021 3022``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3023 Configure a host TAP network backend with ID id. 3024 3025 Use the network script file to configure it and the network script 3026 dfile to deconfigure it. If name is not provided, the OS 3027 automatically provides one. The default network configure script is 3028 ``/etc/qemu-ifup`` and the default network deconfigure script is 3029 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3030 disable script execution. 3031 3032 If running QEMU as an unprivileged user, use the network helper 3033 to configure the TAP interface and attach it to the bridge. 3034 The default network helper executable is 3035 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3036 ``br0``. 3037 3038 ``fd``\ =h can be used to specify the handle of an already opened 3039 host TAP interface. 3040 3041 Examples: 3042 3043 .. parsed-literal:: 3044 3045 #launch a QEMU instance with the default network script 3046 |qemu_system| linux.img -nic tap 3047 3048 .. parsed-literal:: 3049 3050 #launch a QEMU instance with two NICs, each one connected 3051 #to a TAP device 3052 |qemu_system| linux.img \\ 3053 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3054 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3055 3056 .. parsed-literal:: 3057 3058 #launch a QEMU instance with the default network helper to 3059 #connect a TAP device to bridge br0 3060 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3061 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3062 3063``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3064 Connect a host TAP network interface to a host bridge device. 3065 3066 Use the network helper helper to configure the TAP interface and 3067 attach it to the bridge. The default network helper executable is 3068 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3069 ``br0``. 3070 3071 Examples: 3072 3073 .. parsed-literal:: 3074 3075 #launch a QEMU instance with the default network helper to 3076 #connect a TAP device to bridge br0 3077 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3078 3079 .. parsed-literal:: 3080 3081 #launch a QEMU instance with the default network helper to 3082 #connect a TAP device to bridge qemubr0 3083 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3084 3085``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3086 This host network backend can be used to connect the guest's network 3087 to another QEMU virtual machine using a TCP socket connection. If 3088 ``listen`` is specified, QEMU waits for incoming connections on port 3089 (host is optional). ``connect`` is used to connect to another QEMU 3090 instance using the ``listen`` option. ``fd``\ =h specifies an 3091 already opened TCP socket. 3092 3093 Example: 3094 3095 .. parsed-literal:: 3096 3097 # launch a first QEMU instance 3098 |qemu_system| linux.img \\ 3099 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3100 -netdev socket,id=n1,listen=:1234 3101 # connect the network of this instance to the network of the first instance 3102 |qemu_system| linux.img \\ 3103 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3104 -netdev socket,id=n2,connect=127.0.0.1:1234 3105 3106``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3107 Configure a socket host network backend to share the guest's network 3108 traffic with another QEMU virtual machines using a UDP multicast 3109 socket, effectively making a bus for every QEMU with same multicast 3110 address maddr and port. NOTES: 3111 3112 1. Several QEMU can be running on different hosts and share same bus 3113 (assuming correct multicast setup for these hosts). 3114 3115 2. mcast support is compatible with User Mode Linux (argument 3116 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3117 3118 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3119 3120 Example: 3121 3122 .. parsed-literal:: 3123 3124 # launch one QEMU instance 3125 |qemu_system| linux.img \\ 3126 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3127 -netdev socket,id=n1,mcast=230.0.0.1:1234 3128 # launch another QEMU instance on same "bus" 3129 |qemu_system| linux.img \\ 3130 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3131 -netdev socket,id=n2,mcast=230.0.0.1:1234 3132 # launch yet another QEMU instance on same "bus" 3133 |qemu_system| linux.img \\ 3134 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3135 -netdev socket,id=n3,mcast=230.0.0.1:1234 3136 3137 Example (User Mode Linux compat.): 3138 3139 .. parsed-literal:: 3140 3141 # launch QEMU instance (note mcast address selected is UML's default) 3142 |qemu_system| linux.img \\ 3143 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3144 -netdev socket,id=n1,mcast=239.192.168.1:1102 3145 # launch UML 3146 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3147 3148 Example (send packets from host's 1.2.3.4): 3149 3150 .. parsed-literal:: 3151 3152 |qemu_system| linux.img \\ 3153 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3154 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3155 3156``-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]`` 3157 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3158 is a popular protocol to transport Ethernet (and other Layer 2) data 3159 frames between two systems. It is present in routers, firewalls and 3160 the Linux kernel (from version 3.3 onwards). 3161 3162 This transport allows a VM to communicate to another VM, router or 3163 firewall directly. 3164 3165 ``src=srcaddr`` 3166 source address (mandatory) 3167 3168 ``dst=dstaddr`` 3169 destination address (mandatory) 3170 3171 ``udp`` 3172 select udp encapsulation (default is ip). 3173 3174 ``srcport=srcport`` 3175 source udp port. 3176 3177 ``dstport=dstport`` 3178 destination udp port. 3179 3180 ``ipv6`` 3181 force v6, otherwise defaults to v4. 3182 3183 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3184 Cookies are a weak form of security in the l2tpv3 specification. 3185 Their function is mostly to prevent misconfiguration. By default 3186 they are 32 bit. 3187 3188 ``cookie64`` 3189 Set cookie size to 64 bit instead of the default 32 3190 3191 ``counter=off`` 3192 Force a 'cut-down' L2TPv3 with no counter as in 3193 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3194 3195 ``pincounter=on`` 3196 Work around broken counter handling in peer. This may also help 3197 on networks which have packet reorder. 3198 3199 ``offset=offset`` 3200 Add an extra offset between header and data 3201 3202 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3203 the bridge br-lan on the remote Linux host 1.2.3.4: 3204 3205 .. parsed-literal:: 3206 3207 # Setup tunnel on linux host using raw ip as encapsulation 3208 # on 1.2.3.4 3209 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3210 encap udp udp_sport 16384 udp_dport 16384 3211 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3212 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3213 ifconfig vmtunnel0 mtu 1500 3214 ifconfig vmtunnel0 up 3215 brctl addif br-lan vmtunnel0 3216 3217 3218 # on 4.3.2.1 3219 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3220 3221 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3222 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3223 3224``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3225 Configure VDE backend to connect to PORT n of a vde switch running 3226 on host and listening for incoming connections on socketpath. Use 3227 GROUP groupname and MODE octalmode to change default ownership and 3228 permissions for communication port. This option is only available if 3229 QEMU has been compiled with vde support enabled. 3230 3231 Example: 3232 3233 .. parsed-literal:: 3234 3235 # launch vde switch 3236 vde_switch -F -sock /tmp/myswitch 3237 # launch QEMU instance 3238 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3239 3240``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3241 Establish a vhost-user netdev, backed by a chardev id. The chardev 3242 should be a unix domain socket backed one. The vhost-user uses a 3243 specifically defined protocol to pass vhost ioctl replacement 3244 messages to an application on the other end of the socket. On 3245 non-MSIX guests, the feature can be forced with vhostforce. Use 3246 'queues=n' to specify the number of queues to be created for 3247 multiqueue vhost-user. 3248 3249 Example: 3250 3251 :: 3252 3253 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3254 -numa node,memdev=mem \ 3255 -chardev socket,id=chr0,path=/path/to/socket \ 3256 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3257 -device virtio-net-pci,netdev=net0 3258 3259``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3260 Establish a vhost-vdpa netdev. 3261 3262 vDPA device is a device that uses a datapath which complies with 3263 the virtio specifications with a vendor specific control path. 3264 vDPA devices can be both physically located on the hardware or 3265 emulated by software. 3266 3267``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3268 Create a hub port on the emulated hub with ID hubid. 3269 3270 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3271 instead of a single netdev. Alternatively, you can also connect the 3272 hubport to another netdev with ID nd by using the ``netdev=nd`` 3273 option. 3274 3275``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3276 Legacy option to configure or create an on-board (or machine 3277 default) Network Interface Card(NIC) and connect it either to the 3278 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3279 If model is omitted, then the default NIC model associated with the 3280 machine type is used. Note that the default NIC model may change in 3281 future QEMU releases, so it is highly recommended to always specify 3282 a model. Optionally, the MAC address can be changed to mac, the 3283 device address set to addr (PCI cards only), and a name can be 3284 assigned for use in monitor commands. Optionally, for PCI cards, you 3285 can specify the number v of MSI-X vectors that the card should have; 3286 this option currently only affects virtio cards; set v = 0 to 3287 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3288 created. QEMU can emulate several different models of network card. 3289 Use ``-net nic,model=help`` for a list of available devices for your 3290 target. 3291 3292``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3293 Configure a host network backend (with the options corresponding to 3294 the same ``-netdev`` option) and connect it to the emulated hub 0 3295 (the default hub). Use name to specify the name of the hub port. 3296ERST 3297 3298DEFHEADING() 3299 3300DEFHEADING(Character device options:) 3301 3302DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3303 "-chardev help\n" 3304 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3305 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3306 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3307 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3308 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3309 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3310 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3311 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3312 " [,logfile=PATH][,logappend=on|off]\n" 3313 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3314 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3315 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3316 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3317 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3318 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3319#ifdef _WIN32 3320 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3321 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3322#else 3323 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3324 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3325#endif 3326#ifdef CONFIG_BRLAPI 3327 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3328#endif 3329#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3330 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3331 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3332 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3333#endif 3334#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3335 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3336 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3337#endif 3338#if defined(CONFIG_SPICE) 3339 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3340 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3341#endif 3342 , QEMU_ARCH_ALL 3343) 3344 3345SRST 3346The general form of a character device option is: 3347 3348``-chardev backend,id=id[,mux=on|off][,options]`` 3349 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3350 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3351 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3352 ``spicevmc``, ``spiceport``. The specific backend will determine the 3353 applicable options. 3354 3355 Use ``-chardev help`` to print all available chardev backend types. 3356 3357 All devices must have an id, which can be any string up to 127 3358 characters long. It is used to uniquely identify this device in 3359 other command line directives. 3360 3361 A character device may be used in multiplexing mode by multiple 3362 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3363 a "1:N" device, and here the "1" end is your specified chardev 3364 backend, and the "N" end is the various parts of QEMU that can talk 3365 to a chardev. If you create a chardev with ``id=myid`` and 3366 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3367 and you can then configure multiple front ends to use that chardev 3368 ID for their input/output. Up to four different front ends can be 3369 connected to a single multiplexed chardev. (Without multiplexing 3370 enabled, a chardev can only be used by a single front end.) For 3371 instance you could use this to allow a single stdio chardev to be 3372 used by two serial ports and the QEMU monitor: 3373 3374 :: 3375 3376 -chardev stdio,mux=on,id=char0 \ 3377 -mon chardev=char0,mode=readline \ 3378 -serial chardev:char0 \ 3379 -serial chardev:char0 3380 3381 You can have more than one multiplexer in a system configuration; 3382 for instance you could have a TCP port multiplexed between UART 0 3383 and UART 1, and stdio multiplexed between the QEMU monitor and a 3384 parallel port: 3385 3386 :: 3387 3388 -chardev stdio,mux=on,id=char0 \ 3389 -mon chardev=char0,mode=readline \ 3390 -parallel chardev:char0 \ 3391 -chardev tcp,...,mux=on,id=char1 \ 3392 -serial chardev:char1 \ 3393 -serial chardev:char1 3394 3395 When you're using a multiplexed character device, some escape 3396 sequences are interpreted in the input. See the chapter about 3397 :ref:`keys in the character backend multiplexer` in the 3398 System Emulation Users Guide for more details. 3399 3400 Note that some other command line options may implicitly create 3401 multiplexed character backends; for instance ``-serial mon:stdio`` 3402 creates a multiplexed stdio backend connected to the serial port and 3403 the QEMU monitor, and ``-nographic`` also multiplexes the console 3404 and the monitor to stdio. 3405 3406 There is currently no support for multiplexing in the other 3407 direction (where a single QEMU front end takes input and output from 3408 multiple chardevs). 3409 3410 Every backend supports the ``logfile`` option, which supplies the 3411 path to a file to record all data transmitted via the backend. The 3412 ``logappend`` option controls whether the log file will be truncated 3413 or appended to when opened. 3414 3415The available backends are: 3416 3417``-chardev null,id=id`` 3418 A void device. This device will not emit any data, and will drop any 3419 data it receives. The null backend does not take any options. 3420 3421``-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]`` 3422 Create a two-way stream socket, which can be either a TCP or a unix 3423 socket. A unix socket will be created if ``path`` is specified. 3424 Behaviour is undefined if TCP options are specified for a unix 3425 socket. 3426 3427 ``server=on|off`` specifies that the socket shall be a listening socket. 3428 3429 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3430 to connect to a listening socket. 3431 3432 ``telnet=on|off`` specifies that traffic on the socket should interpret 3433 telnet escape sequences. 3434 3435 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3436 communication. 3437 3438 ``reconnect`` sets the timeout for reconnecting on non-server 3439 sockets when the remote end goes away. qemu will delay this many 3440 seconds and then attempt to reconnect. Zero disables reconnecting, 3441 and is the default. 3442 3443 ``tls-creds`` requests enablement of the TLS protocol for 3444 encryption, and specifies the id of the TLS credentials to use for 3445 the handshake. The credentials must be previously created with the 3446 ``-object tls-creds`` argument. 3447 3448 ``tls-auth`` provides the ID of the QAuthZ authorization object 3449 against which the client's x509 distinguished name will be 3450 validated. This object is only resolved at time of use, so can be 3451 deleted and recreated on the fly while the chardev server is active. 3452 If missing, it will default to denying access. 3453 3454 TCP and unix socket options are given below: 3455 3456 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3457 ``host`` for a listening socket specifies the local address to 3458 be bound. For a connecting socket species the remote host to 3459 connect to. ``host`` is optional for listening sockets. If not 3460 specified it defaults to ``0.0.0.0``. 3461 3462 ``port`` for a listening socket specifies the local port to be 3463 bound. For a connecting socket specifies the port on the remote 3464 host to connect to. ``port`` can be given as either a port 3465 number or a service name. ``port`` is required. 3466 3467 ``to`` is only relevant to listening sockets. If it is 3468 specified, and ``port`` cannot be bound, QEMU will attempt to 3469 bind to subsequent ports up to and including ``to`` until it 3470 succeeds. ``to`` must be specified as a port number. 3471 3472 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3473 or IPv6 must be used. If neither is specified the socket may 3474 use either protocol. 3475 3476 ``nodelay=on|off`` disables the Nagle algorithm. 3477 3478 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3479 ``path`` specifies the local path of the unix socket. ``path`` 3480 is required. 3481 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3482 rather than the filesystem. Optional, defaults to false. 3483 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3484 rather than the full sun_path length. Optional, defaults to true. 3485 3486``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3487 Sends all traffic from the guest to a remote host over UDP. 3488 3489 ``host`` specifies the remote host to connect to. If not specified 3490 it defaults to ``localhost``. 3491 3492 ``port`` specifies the port on the remote host to connect to. 3493 ``port`` is required. 3494 3495 ``localaddr`` specifies the local address to bind to. If not 3496 specified it defaults to ``0.0.0.0``. 3497 3498 ``localport`` specifies the local port to bind to. If not specified 3499 any available local port will be used. 3500 3501 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3502 If neither is specified the device may use either protocol. 3503 3504``-chardev msmouse,id=id`` 3505 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3506 does not take any options. 3507 3508``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3509 Connect to a QEMU text console. ``vc`` may optionally be given a 3510 specific size. 3511 3512 ``width`` and ``height`` specify the width and height respectively 3513 of the console, in pixels. 3514 3515 ``cols`` and ``rows`` specify that the console be sized to fit a 3516 text console with the given dimensions. 3517 3518``-chardev ringbuf,id=id[,size=size]`` 3519 Create a ring buffer with fixed size ``size``. size must be a power 3520 of two and defaults to ``64K``. 3521 3522``-chardev file,id=id,path=path`` 3523 Log all traffic received from the guest to a file. 3524 3525 ``path`` specifies the path of the file to be opened. This file will 3526 be created if it does not already exist, and overwritten if it does. 3527 ``path`` is required. 3528 3529``-chardev pipe,id=id,path=path`` 3530 Create a two-way connection to the guest. The behaviour differs 3531 slightly between Windows hosts and other hosts: 3532 3533 On Windows, a single duplex pipe will be created at 3534 ``\\.pipe\path``. 3535 3536 On other hosts, 2 pipes will be created called ``path.in`` and 3537 ``path.out``. Data written to ``path.in`` will be received by the 3538 guest. Data written by the guest can be read from ``path.out``. QEMU 3539 will not create these fifos, and requires them to be present. 3540 3541 ``path`` forms part of the pipe path as described above. ``path`` is 3542 required. 3543 3544``-chardev console,id=id`` 3545 Send traffic from the guest to QEMU's standard output. ``console`` 3546 does not take any options. 3547 3548 ``console`` is only available on Windows hosts. 3549 3550``-chardev serial,id=id,path=path`` 3551 Send traffic from the guest to a serial device on the host. 3552 3553 On Unix hosts serial will actually accept any tty device, not only 3554 serial lines. 3555 3556 ``path`` specifies the name of the serial device to open. 3557 3558``-chardev pty,id=id`` 3559 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3560 does not take any options. 3561 3562 ``pty`` is not available on Windows hosts. 3563 3564``-chardev stdio,id=id[,signal=on|off]`` 3565 Connect to standard input and standard output of the QEMU process. 3566 3567 ``signal`` controls if signals are enabled on the terminal, that 3568 includes exiting QEMU with the key sequence Control-c. This option 3569 is enabled by default, use ``signal=off`` to disable it. 3570 3571``-chardev braille,id=id`` 3572 Connect to a local BrlAPI server. ``braille`` does not take any 3573 options. 3574 3575``-chardev tty,id=id,path=path`` 3576 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3577 and DragonFlyBSD hosts. It is an alias for ``serial``. 3578 3579 ``path`` specifies the path to the tty. ``path`` is required. 3580 3581``-chardev parallel,id=id,path=path`` 3582 \ 3583``-chardev parport,id=id,path=path`` 3584 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3585 hosts. 3586 3587 Connect to a local parallel port. 3588 3589 ``path`` specifies the path to the parallel port device. ``path`` is 3590 required. 3591 3592``-chardev spicevmc,id=id,debug=debug,name=name`` 3593 ``spicevmc`` is only available when spice support is built in. 3594 3595 ``debug`` debug level for spicevmc 3596 3597 ``name`` name of spice channel to connect to 3598 3599 Connect to a spice virtual machine channel, such as vdiport. 3600 3601``-chardev spiceport,id=id,debug=debug,name=name`` 3602 ``spiceport`` is only available when spice support is built in. 3603 3604 ``debug`` debug level for spicevmc 3605 3606 ``name`` name of spice port to connect to 3607 3608 Connect to a spice port, allowing a Spice client to handle the 3609 traffic identified by a name (preferably a fqdn). 3610ERST 3611 3612DEFHEADING() 3613 3614#ifdef CONFIG_TPM 3615DEFHEADING(TPM device options:) 3616 3617DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3618 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3619 " use path to provide path to a character device; default is /dev/tpm0\n" 3620 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3621 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3622 "-tpmdev emulator,id=id,chardev=dev\n" 3623 " configure the TPM device using chardev backend\n", 3624 QEMU_ARCH_ALL) 3625SRST 3626The general form of a TPM device option is: 3627 3628``-tpmdev backend,id=id[,options]`` 3629 The specific backend type will determine the applicable options. The 3630 ``-tpmdev`` option creates the TPM backend and requires a 3631 ``-device`` option that specifies the TPM frontend interface model. 3632 3633 Use ``-tpmdev help`` to print all available TPM backend types. 3634 3635The available backends are: 3636 3637``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3638 (Linux-host only) Enable access to the host's TPM using the 3639 passthrough driver. 3640 3641 ``path`` specifies the path to the host's TPM device, i.e., on a 3642 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3643 default ``/dev/tpm0`` is used. 3644 3645 ``cancel-path`` specifies the path to the host TPM device's sysfs 3646 entry allowing for cancellation of an ongoing TPM command. 3647 ``cancel-path`` is optional and by default QEMU will search for the 3648 sysfs entry to use. 3649 3650 Some notes about using the host's TPM with the passthrough driver: 3651 3652 The TPM device accessed by the passthrough driver must not be used 3653 by any other application on the host. 3654 3655 Since the host's firmware (BIOS/UEFI) has already initialized the 3656 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3657 the TPM again and may therefore not show a TPM-specific menu that 3658 would otherwise allow the user to configure the TPM, e.g., allow the 3659 user to enable/disable or activate/deactivate the TPM. Further, if 3660 TPM ownership is released from within a VM then the host's TPM will 3661 get disabled and deactivated. To enable and activate the TPM again 3662 afterwards, the host has to be rebooted and the user is required to 3663 enter the firmware's menu to enable and activate the TPM. If the TPM 3664 is left disabled and/or deactivated most TPM commands will fail. 3665 3666 To create a passthrough TPM use the following two options: 3667 3668 :: 3669 3670 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3671 3672 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3673 ``tpmdev=tpm0`` in the device option. 3674 3675``-tpmdev emulator,id=id,chardev=dev`` 3676 (Linux-host only) Enable access to a TPM emulator using Unix domain 3677 socket based chardev backend. 3678 3679 ``chardev`` specifies the unique ID of a character device backend 3680 that provides connection to the software TPM server. 3681 3682 To create a TPM emulator backend device with chardev socket backend: 3683 3684 :: 3685 3686 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3687ERST 3688 3689DEFHEADING() 3690 3691#endif 3692 3693DEFHEADING(Boot Image or Kernel specific:) 3694SRST 3695There are broadly 4 ways you can boot a system with QEMU. 3696 3697 - specify a firmware and let it control finding a kernel 3698 - specify a firmware and pass a hint to the kernel to boot 3699 - direct kernel image boot 3700 - manually load files into the guest's address space 3701 3702The third method is useful for quickly testing kernels but as there is 3703no firmware to pass configuration information to the kernel the 3704hardware must either be probeable, the kernel built for the exact 3705configuration or passed some configuration data (e.g. a DTB blob) 3706which tells the kernel what drivers it needs. This exact details are 3707often hardware specific. 3708 3709The final method is the most generic way of loading images into the 3710guest address space and used mostly for ``bare metal`` type 3711development where the reset vectors of the processor are taken into 3712account. 3713 3714ERST 3715 3716SRST 3717 3718For x86 machines and some other architectures ``-bios`` will generally 3719do the right thing with whatever it is given. For other machines the 3720more strict ``-pflash`` option needs an image that is sized for the 3721flash device for the given machine type. 3722 3723Please see the :ref:`system-targets-ref` section of the manual for 3724more detailed documentation. 3725 3726ERST 3727 3728DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3729 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3730SRST 3731``-bios file`` 3732 Set the filename for the BIOS. 3733ERST 3734 3735DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3736 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3737SRST 3738``-pflash file`` 3739 Use file as a parallel flash image. 3740ERST 3741 3742SRST 3743 3744The kernel options were designed to work with Linux kernels although 3745other things (like hypervisors) can be packaged up as a kernel 3746executable image. The exact format of a executable image is usually 3747architecture specific. 3748 3749The way in which the kernel is started (what address it is loaded at, 3750what if any information is passed to it via CPU registers, the state 3751of the hardware when it is started, and so on) is also architecture 3752specific. Typically it follows the specification laid down by the 3753Linux kernel for how kernels for that architecture must be started. 3754 3755ERST 3756 3757DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3758 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3759SRST 3760``-kernel bzImage`` 3761 Use bzImage as kernel image. The kernel can be either a Linux kernel 3762 or in multiboot format. 3763ERST 3764 3765DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3766 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3767SRST 3768``-append cmdline`` 3769 Use cmdline as kernel command line 3770ERST 3771 3772DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3773 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3774SRST 3775``-initrd file`` 3776 Use file as initial ram disk. 3777 3778``-initrd "file1 arg=foo,file2"`` 3779 This syntax is only available with multiboot. 3780 3781 Use file1 and file2 as modules and pass arg=foo as parameter to the 3782 first module. 3783ERST 3784 3785DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3786 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3787SRST 3788``-dtb file`` 3789 Use file as a device tree binary (dtb) image and pass it to the 3790 kernel on boot. 3791ERST 3792 3793SRST 3794 3795Finally you can also manually load images directly into the address 3796space of the guest. This is most useful for developers who already 3797know the layout of their guest and take care to ensure something sane 3798will happen when the reset vector executes. 3799 3800The generic loader can be invoked by using the loader device: 3801 3802``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3803 3804there is also the guest loader which operates in a similar way but 3805tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3806the guest image is: 3807 3808``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3809 3810ERST 3811 3812DEFHEADING() 3813 3814DEFHEADING(Debug/Expert options:) 3815 3816DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3817 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3818 " Policy for handling deprecated management interfaces\n" 3819 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3820 " Policy for handling unstable management interfaces\n", 3821 QEMU_ARCH_ALL) 3822SRST 3823``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3824 Set policy for handling deprecated management interfaces (experimental): 3825 3826 ``deprecated-input=accept`` (default) 3827 Accept deprecated commands and arguments 3828 ``deprecated-input=reject`` 3829 Reject deprecated commands and arguments 3830 ``deprecated-input=crash`` 3831 Crash on deprecated commands and arguments 3832 ``deprecated-output=accept`` (default) 3833 Emit deprecated command results and events 3834 ``deprecated-output=hide`` 3835 Suppress deprecated command results and events 3836 3837 Limitation: covers only syntactic aspects of QMP. 3838 3839``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3840 Set policy for handling unstable management interfaces (experimental): 3841 3842 ``unstable-input=accept`` (default) 3843 Accept unstable commands and arguments 3844 ``unstable-input=reject`` 3845 Reject unstable commands and arguments 3846 ``unstable-input=crash`` 3847 Crash on unstable commands and arguments 3848 ``unstable-output=accept`` (default) 3849 Emit unstable command results and events 3850 ``unstable-output=hide`` 3851 Suppress unstable command results and events 3852 3853 Limitation: covers only syntactic aspects of QMP. 3854ERST 3855 3856DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3857 "-fw_cfg [name=]<name>,file=<file>\n" 3858 " add named fw_cfg entry with contents from file\n" 3859 "-fw_cfg [name=]<name>,string=<str>\n" 3860 " add named fw_cfg entry with contents from string\n", 3861 QEMU_ARCH_ALL) 3862SRST 3863``-fw_cfg [name=]name,file=file`` 3864 Add named fw\_cfg entry with contents from file file. 3865 3866``-fw_cfg [name=]name,string=str`` 3867 Add named fw\_cfg entry with contents from string str. 3868 3869 The terminating NUL character of the contents of str will not be 3870 included as part of the fw\_cfg item data. To insert contents with 3871 embedded NUL characters, you have to use the file parameter. 3872 3873 The fw\_cfg entries are passed by QEMU through to the guest. 3874 3875 Example: 3876 3877 :: 3878 3879 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3880 3881 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3882 from ./my\_blob.bin. 3883ERST 3884 3885DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3886 "-serial dev redirect the serial port to char device 'dev'\n", 3887 QEMU_ARCH_ALL) 3888SRST 3889``-serial dev`` 3890 Redirect the virtual serial port to host character device dev. The 3891 default device is ``vc`` in graphical mode and ``stdio`` in non 3892 graphical mode. 3893 3894 This option can be used several times to simulate up to 4 serial 3895 ports. 3896 3897 Use ``-serial none`` to disable all serial ports. 3898 3899 Available character devices are: 3900 3901 ``vc[:WxH]`` 3902 Virtual console. Optionally, a width and height can be given in 3903 pixel with 3904 3905 :: 3906 3907 vc:800x600 3908 3909 It is also possible to specify width or height in characters: 3910 3911 :: 3912 3913 vc:80Cx24C 3914 3915 ``pty`` 3916 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3917 3918 ``none`` 3919 No device is allocated. 3920 3921 ``null`` 3922 void device 3923 3924 ``chardev:id`` 3925 Use a named character device defined with the ``-chardev`` 3926 option. 3927 3928 ``/dev/XXX`` 3929 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3930 port parameters are set according to the emulated ones. 3931 3932 ``/dev/parportN`` 3933 [Linux only, parallel port only] Use host parallel port N. 3934 Currently SPP and EPP parallel port features can be used. 3935 3936 ``file:filename`` 3937 Write output to filename. No character can be read. 3938 3939 ``stdio`` 3940 [Unix only] standard input/output 3941 3942 ``pipe:filename`` 3943 name pipe filename 3944 3945 ``COMn`` 3946 [Windows only] Use host serial port n 3947 3948 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3949 This implements UDP Net Console. When remote\_host or src\_ip 3950 are not specified they default to ``0.0.0.0``. When not using a 3951 specified src\_port a random port is automatically chosen. 3952 3953 If you just want a simple readonly console you can use 3954 ``netcat`` or ``nc``, by starting QEMU with: 3955 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3956 QEMU writes something to that port it will appear in the 3957 netconsole session. 3958 3959 If you plan to send characters back via netconsole or you want 3960 to stop and start QEMU a lot of times, you should have QEMU use 3961 the same source port each time by using something like ``-serial 3962 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3963 version of netcat which can listen to a TCP port and send and 3964 receive characters via udp. If you have a patched version of 3965 netcat which activates telnet remote echo and single char 3966 transfer, then you can use the following options to set up a 3967 netcat redirector to allow telnet on port 5555 to access the 3968 QEMU port. 3969 3970 ``QEMU Options:`` 3971 -serial udp::4555@:4556 3972 3973 ``netcat options:`` 3974 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3975 3976 ``telnet options:`` 3977 localhost 5555 3978 3979 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3980 The TCP Net Console has two modes of operation. It can send the 3981 serial I/O to a location or wait for a connection from a 3982 location. By default the TCP Net Console is sent to host at the 3983 port. If you use the ``server=on`` option QEMU will wait for a client 3984 socket application to connect to the port before continuing, 3985 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3986 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3987 option only applies if ``server=no`` is set, if the connection goes 3988 down it will attempt to reconnect at the given interval. If host 3989 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3990 time is accepted. You can use ``telnet=on`` to connect to the 3991 corresponding character device. 3992 3993 ``Example to send tcp console to 192.168.0.2 port 4444`` 3994 -serial tcp:192.168.0.2:4444 3995 3996 ``Example to listen and wait on port 4444 for connection`` 3997 -serial tcp::4444,server=on 3998 3999 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4000 -serial tcp:192.168.0.100:4444,server=on,wait=off 4001 4002 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4003 The telnet protocol is used instead of raw tcp sockets. The 4004 options work the same as if you had specified ``-serial tcp``. 4005 The difference is that the port acts like a telnet server or 4006 client using telnet option negotiation. This will also allow you 4007 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4008 supports sending the break sequence. Typically in unix telnet 4009 you do it with Control-] and then type "send break" followed by 4010 pressing the enter key. 4011 4012 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4013 The WebSocket protocol is used instead of raw tcp socket. The 4014 port acts as a WebSocket server. Client mode is not supported. 4015 4016 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4017 A unix domain socket is used instead of a tcp socket. The option 4018 works the same as if you had specified ``-serial tcp`` except 4019 the unix domain socket path is used for connections. 4020 4021 ``mon:dev_string`` 4022 This is a special option to allow the monitor to be multiplexed 4023 onto another serial port. The monitor is accessed with key 4024 sequence of Control-a and then pressing c. dev\_string should be 4025 any one of the serial devices specified above. An example to 4026 multiplex the monitor onto a telnet server listening on port 4027 4444 would be: 4028 4029 ``-serial mon:telnet::4444,server=on,wait=off`` 4030 4031 When the monitor is multiplexed to stdio in this way, Ctrl+C 4032 will not terminate QEMU any more but will be passed to the guest 4033 instead. 4034 4035 ``braille`` 4036 Braille device. This will use BrlAPI to display the braille 4037 output on a real or fake device. 4038 4039 ``msmouse`` 4040 Three button serial mouse. Configure the guest to use Microsoft 4041 protocol. 4042ERST 4043 4044DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4045 "-parallel dev redirect the parallel port to char device 'dev'\n", 4046 QEMU_ARCH_ALL) 4047SRST 4048``-parallel dev`` 4049 Redirect the virtual parallel port to host device dev (same devices 4050 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4051 to use hardware devices connected on the corresponding host parallel 4052 port. 4053 4054 This option can be used several times to simulate up to 3 parallel 4055 ports. 4056 4057 Use ``-parallel none`` to disable all parallel ports. 4058ERST 4059 4060DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4061 "-monitor dev redirect the monitor to char device 'dev'\n", 4062 QEMU_ARCH_ALL) 4063SRST 4064``-monitor dev`` 4065 Redirect the monitor to host device dev (same devices as the serial 4066 port). The default device is ``vc`` in graphical mode and ``stdio`` 4067 in non graphical mode. Use ``-monitor none`` to disable the default 4068 monitor. 4069ERST 4070DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4071 "-qmp dev like -monitor but opens in 'control' mode\n", 4072 QEMU_ARCH_ALL) 4073SRST 4074``-qmp dev`` 4075 Like -monitor but opens in 'control' mode. 4076ERST 4077DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4078 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4079 QEMU_ARCH_ALL) 4080SRST 4081``-qmp-pretty dev`` 4082 Like -qmp but uses pretty JSON formatting. 4083ERST 4084 4085DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4086 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4087SRST 4088``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4089 Setup monitor on chardev name. ``mode=control`` configures 4090 a QMP monitor (a JSON RPC-style protocol) and it is not the 4091 same as HMP, the human monitor that has a "(qemu)" prompt. 4092 ``pretty`` is only valid when ``mode=control``, 4093 turning on JSON pretty printing to ease 4094 human reading and debugging. 4095ERST 4096 4097DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4098 "-debugcon dev redirect the debug console to char device 'dev'\n", 4099 QEMU_ARCH_ALL) 4100SRST 4101``-debugcon dev`` 4102 Redirect the debug console to host device dev (same devices as the 4103 serial port). The debug console is an I/O port which is typically 4104 port 0xe9; writing to that I/O port sends output to this device. The 4105 default device is ``vc`` in graphical mode and ``stdio`` in non 4106 graphical mode. 4107ERST 4108 4109DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4110 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4111SRST 4112``-pidfile file`` 4113 Store the QEMU process PID in file. It is useful if you launch QEMU 4114 from a script. 4115ERST 4116 4117DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4118 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4119SRST 4120``-singlestep`` 4121 Run the emulation in single step mode. 4122ERST 4123 4124DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4125 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4126 QEMU_ARCH_ALL) 4127SRST 4128``--preconfig`` 4129 Pause QEMU for interactive configuration before the machine is 4130 created, which allows querying and configuring properties that will 4131 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4132 exit the preconfig state and move to the next state (i.e. run guest 4133 if -S isn't used or pause the second time if -S is used). This 4134 option is experimental. 4135ERST 4136 4137DEF("S", 0, QEMU_OPTION_S, \ 4138 "-S freeze CPU at startup (use 'c' to start execution)\n", 4139 QEMU_ARCH_ALL) 4140SRST 4141``-S`` 4142 Do not start CPU at startup (you must type 'c' in the monitor). 4143ERST 4144 4145DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4146 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4147 " run qemu with overcommit hints\n" 4148 " mem-lock=on|off controls memory lock support (default: off)\n" 4149 " cpu-pm=on|off controls cpu power management (default: off)\n", 4150 QEMU_ARCH_ALL) 4151SRST 4152``-overcommit mem-lock=on|off`` 4153 \ 4154``-overcommit cpu-pm=on|off`` 4155 Run qemu with hints about host resource overcommit. The default is 4156 to assume that host overcommits all resources. 4157 4158 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4159 (disabled by default). This works when host memory is not 4160 overcommitted and reduces the worst-case latency for guest. 4161 4162 Guest ability to manage power state of host cpus (increasing latency 4163 for other processes on the same host cpu, but decreasing latency for 4164 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4165 works best when host CPU is not overcommitted. When used, host 4166 estimates of CPU cycle and power utilization will be incorrect, not 4167 taking into account guest idle time. 4168ERST 4169 4170DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4171 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4172 " the guest without waiting for gdb to connect; use -S too\n" 4173 " if you want it to not start execution.)\n", 4174 QEMU_ARCH_ALL) 4175SRST 4176``-gdb dev`` 4177 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4178 in the System Emulation Users Guide). Note that this option does not pause QEMU 4179 execution -- if you want QEMU to not start the guest until you 4180 connect with gdb and issue a ``continue`` command, you will need to 4181 also pass the ``-S`` option to QEMU. 4182 4183 The most usual configuration is to listen on a local TCP socket:: 4184 4185 -gdb tcp::3117 4186 4187 but you can specify other backends; UDP, pseudo TTY, or even stdio 4188 are all reasonable use cases. For example, a stdio connection 4189 allows you to start QEMU from within gdb and establish the 4190 connection via a pipe: 4191 4192 .. parsed-literal:: 4193 4194 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4195ERST 4196 4197DEF("s", 0, QEMU_OPTION_s, \ 4198 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4199 QEMU_ARCH_ALL) 4200SRST 4201``-s`` 4202 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4203 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4204ERST 4205 4206DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4207 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4208 QEMU_ARCH_ALL) 4209SRST 4210``-d item1[,...]`` 4211 Enable logging of specified items. Use '-d help' for a list of log 4212 items. 4213ERST 4214 4215DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4216 "-D logfile output log to logfile (default stderr)\n", 4217 QEMU_ARCH_ALL) 4218SRST 4219``-D logfile`` 4220 Output log in logfile instead of to stderr 4221ERST 4222 4223DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4224 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4225 QEMU_ARCH_ALL) 4226SRST 4227``-dfilter range1[,...]`` 4228 Filter debug output to that relevant to a range of target addresses. 4229 The filter spec can be either start+size, start-size or start..end 4230 where start end and size are the addresses and sizes required. For 4231 example: 4232 4233 :: 4234 4235 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4236 4237 Will dump output for any code in the 0x1000 sized block starting at 4238 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4239 another 0x1000 sized block starting at 0xffffffc00005f000. 4240ERST 4241 4242DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4243 "-seed number seed the pseudo-random number generator\n", 4244 QEMU_ARCH_ALL) 4245SRST 4246``-seed number`` 4247 Force the guest to use a deterministic pseudo-random number 4248 generator, seeded with number. This does not affect crypto routines 4249 within the host. 4250ERST 4251 4252DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4253 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4254 QEMU_ARCH_ALL) 4255SRST 4256``-L path`` 4257 Set the directory for the BIOS, VGA BIOS and keymaps. 4258 4259 To list all the data directories, use ``-L help``. 4260ERST 4261 4262DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4263 "-enable-kvm enable KVM full virtualization support\n", 4264 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4265 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4266SRST 4267``-enable-kvm`` 4268 Enable KVM full virtualization support. This option is only 4269 available if KVM support is enabled when compiling. 4270ERST 4271 4272DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4273 "-xen-domid id specify xen guest domain id\n", 4274 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4275DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4276 "-xen-attach attach to existing xen domain\n" 4277 " libxl will use this when starting QEMU\n", 4278 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4279DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4280 "-xen-domid-restrict restrict set of available xen operations\n" 4281 " to specified domain id. (Does not affect\n" 4282 " xenpv machine type).\n", 4283 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4284SRST 4285``-xen-domid id`` 4286 Specify xen guest domain id (XEN only). 4287 4288``-xen-attach`` 4289 Attach to existing xen domain. libxl will use this when starting 4290 QEMU (XEN only). Restrict set of available xen operations to 4291 specified domain id (XEN only). 4292ERST 4293 4294DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4295 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4296SRST 4297``-no-reboot`` 4298 Exit instead of rebooting. 4299ERST 4300 4301DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4302 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4303SRST 4304``-no-shutdown`` 4305 Don't exit QEMU on guest shutdown, but instead only stop the 4306 emulation. This allows for instance switching to monitor to commit 4307 changes to the disk image. 4308ERST 4309 4310DEF("action", HAS_ARG, QEMU_OPTION_action, 4311 "-action reboot=reset|shutdown\n" 4312 " action when guest reboots [default=reset]\n" 4313 "-action shutdown=poweroff|pause\n" 4314 " action when guest shuts down [default=poweroff]\n" 4315 "-action panic=pause|shutdown|exit-failure|none\n" 4316 " action when guest panics [default=shutdown]\n" 4317 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4318 " action when watchdog fires [default=reset]\n", 4319 QEMU_ARCH_ALL) 4320SRST 4321``-action event=action`` 4322 The action parameter serves to modify QEMU's default behavior when 4323 certain guest events occur. It provides a generic method for specifying the 4324 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4325 parameters. 4326 4327 Examples: 4328 4329 ``-action panic=none`` 4330 ``-action reboot=shutdown,shutdown=pause`` 4331 ``-watchdog i6300esb -action watchdog=pause`` 4332 4333ERST 4334 4335DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4336 "-loadvm [tag|id]\n" \ 4337 " start right away with a saved state (loadvm in monitor)\n", 4338 QEMU_ARCH_ALL) 4339SRST 4340``-loadvm file`` 4341 Start right away with a saved state (``loadvm`` in monitor) 4342ERST 4343 4344#ifndef _WIN32 4345DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4346 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4347#endif 4348SRST 4349``-daemonize`` 4350 Daemonize the QEMU process after initialization. QEMU will not 4351 detach from standard IO until it is ready to receive connections on 4352 any of its devices. This option is a useful way for external 4353 programs to launch QEMU without having to cope with initialization 4354 race conditions. 4355ERST 4356 4357DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4358 "-option-rom rom load a file, rom, into the option ROM space\n", 4359 QEMU_ARCH_ALL) 4360SRST 4361``-option-rom file`` 4362 Load the contents of file as an option ROM. This option is useful to 4363 load things like EtherBoot. 4364ERST 4365 4366DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4367 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4368 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4369 QEMU_ARCH_ALL) 4370 4371SRST 4372``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4373 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4374 the current UTC or local time, respectively. ``localtime`` is 4375 required for correct date in MS-DOS or Windows. To start at a 4376 specific point in time, provide datetime in the format 4377 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4378 4379 By default the RTC is driven by the host system time. This allows 4380 using of the RTC as accurate reference clock inside the guest, 4381 specifically if the host time is smoothly following an accurate 4382 external reference clock, e.g. via NTP. If you want to isolate the 4383 guest time from the host, you can set ``clock`` to ``rt`` instead, 4384 which provides a host monotonic clock if host support it. To even 4385 prevent the RTC from progressing during suspension, you can set 4386 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4387 recommended especially in icount mode in order to preserve 4388 determinism; however, note that in icount mode the speed of the 4389 virtual clock is variable and can in general differ from the host 4390 clock. 4391 4392 Enable ``driftfix`` (i386 targets only) if you experience time drift 4393 problems, specifically with Windows' ACPI HAL. This option will try 4394 to figure out how many timer interrupts were not processed by the 4395 Windows guest and will re-inject them. 4396ERST 4397 4398DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4399 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4400 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4401 " instruction, enable aligning the host and virtual clocks\n" \ 4402 " or disable real time cpu sleeping, and optionally enable\n" \ 4403 " record-and-replay mode\n", QEMU_ARCH_ALL) 4404SRST 4405``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4406 Enable virtual instruction counter. The virtual cpu will execute one 4407 instruction every 2^N ns of virtual time. If ``auto`` is specified 4408 then the virtual cpu speed will be automatically adjusted to keep 4409 virtual time within a few seconds of real time. 4410 4411 Note that while this option can give deterministic behavior, it does 4412 not provide cycle accurate emulation. Modern CPUs contain 4413 superscalar out of order cores with complex cache hierarchies. The 4414 number of instructions executed often has little or no correlation 4415 with actual performance. 4416 4417 When the virtual cpu is sleeping, the virtual time will advance at 4418 default speed unless ``sleep=on`` is specified. With 4419 ``sleep=on``, the virtual time will jump to the next timer 4420 deadline instantly whenever the virtual cpu goes to sleep mode and 4421 will not advance if no timer is enabled. This behavior gives 4422 deterministic execution times from the guest point of view. 4423 The default if icount is enabled is ``sleep=off``. 4424 ``sleep=on`` cannot be used together with either ``shift=auto`` 4425 or ``align=on``. 4426 4427 ``align=on`` will activate the delay algorithm which will try to 4428 synchronise the host clock and the virtual clock. The goal is to 4429 have a guest running at the real frequency imposed by the shift 4430 option. Whenever the guest clock is behind the host clock and if 4431 ``align=on`` is specified then we print a message to the user to 4432 inform about the delay. Currently this option does not work when 4433 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4434 shift values for which the guest clock runs ahead of the host clock. 4435 Typically this happens when the shift value is high (how high 4436 depends on the host machine). The default if icount is enabled 4437 is ``align=off``. 4438 4439 When the ``rr`` option is specified deterministic record/replay is 4440 enabled. The ``rrfile=`` option must also be provided to 4441 specify the path to the replay log. In record mode data is written 4442 to this file, and in replay mode it is read back. 4443 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4444 name. In record mode, a new VM snapshot with the given name is created 4445 at the start of execution recording. In replay mode this option 4446 specifies the snapshot name used to load the initial VM state. 4447ERST 4448 4449DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4450 "-watchdog model\n" \ 4451 " enable virtual hardware watchdog [default=none]\n", 4452 QEMU_ARCH_ALL) 4453SRST 4454``-watchdog model`` 4455 Create a virtual hardware watchdog device. Once enabled (by a guest 4456 action), the watchdog must be periodically polled by an agent inside 4457 the guest or else the guest will be restarted. Choose a model for 4458 which your guest has drivers. 4459 4460 The model is the model of hardware watchdog to emulate. Use 4461 ``-watchdog help`` to list available hardware models. Only one 4462 watchdog can be enabled for a guest. 4463 4464 The following models may be available: 4465 4466 ``ib700`` 4467 iBASE 700 is a very simple ISA watchdog with a single timer. 4468 4469 ``i6300esb`` 4470 Intel 6300ESB I/O controller hub is a much more featureful 4471 PCI-based dual-timer watchdog. 4472 4473 ``diag288`` 4474 A virtual watchdog for s390x backed by the diagnose 288 4475 hypercall (currently KVM only). 4476ERST 4477 4478DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4479 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4480 " action when watchdog fires [default=reset]\n", 4481 QEMU_ARCH_ALL) 4482SRST 4483``-watchdog-action action`` 4484 The action controls what QEMU will do when the watchdog timer 4485 expires. The default is ``reset`` (forcefully reset the guest). 4486 Other possible actions are: ``shutdown`` (attempt to gracefully 4487 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4488 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4489 guest), ``debug`` (print a debug message and continue), or ``none`` 4490 (do nothing). 4491 4492 Note that the ``shutdown`` action requires that the guest responds 4493 to ACPI signals, which it may not be able to do in the sort of 4494 situations where the watchdog would have expired, and thus 4495 ``-watchdog-action shutdown`` is not recommended for production use. 4496 4497 Examples: 4498 4499 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4500 4501ERST 4502 4503DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4504 "-echr chr set terminal escape character instead of ctrl-a\n", 4505 QEMU_ARCH_ALL) 4506SRST 4507``-echr numeric_ascii_value`` 4508 Change the escape character used for switching to the monitor when 4509 using monitor and serial sharing. The default is ``0x01`` when using 4510 the ``-nographic`` option. ``0x01`` is equal to pressing 4511 ``Control-a``. You can select a different character from the ascii 4512 control keys where 1 through 26 map to Control-a through Control-z. 4513 For instance you could use the either of the following to change the 4514 escape character to Control-t. 4515 4516 ``-echr 0x14``; \ ``-echr 20`` 4517 4518ERST 4519 4520DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4521 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4522 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4523 "-incoming unix:socketpath\n" \ 4524 " prepare for incoming migration, listen on\n" \ 4525 " specified protocol and socket address\n" \ 4526 "-incoming fd:fd\n" \ 4527 "-incoming exec:cmdline\n" \ 4528 " accept incoming migration on given file descriptor\n" \ 4529 " or from given external command\n" \ 4530 "-incoming defer\n" \ 4531 " wait for the URI to be specified via migrate_incoming\n", 4532 QEMU_ARCH_ALL) 4533SRST 4534``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4535 \ 4536``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4537 Prepare for incoming migration, listen on a given tcp port. 4538 4539``-incoming unix:socketpath`` 4540 Prepare for incoming migration, listen on a given unix socket. 4541 4542``-incoming fd:fd`` 4543 Accept incoming migration from a given filedescriptor. 4544 4545``-incoming exec:cmdline`` 4546 Accept incoming migration as an output from specified external 4547 command. 4548 4549``-incoming defer`` 4550 Wait for the URI to be specified via migrate\_incoming. The monitor 4551 can be used to change settings (such as migration parameters) prior 4552 to issuing the migrate\_incoming to allow the migration to begin. 4553ERST 4554 4555DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4556 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4557SRST 4558``-only-migratable`` 4559 Only allow migratable devices. Devices will not be allowed to enter 4560 an unmigratable state. 4561ERST 4562 4563DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4564 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4565SRST 4566``-nodefaults`` 4567 Don't create default devices. Normally, QEMU sets the default 4568 devices like serial port, parallel port, virtual console, monitor 4569 device, VGA adapter, floppy and CD-ROM drive and others. The 4570 ``-nodefaults`` option will disable all those default devices. 4571ERST 4572 4573#ifndef _WIN32 4574DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4575 "-chroot dir chroot to dir just before starting the VM\n", 4576 QEMU_ARCH_ALL) 4577#endif 4578SRST 4579``-chroot dir`` 4580 Immediately before starting guest execution, chroot to the specified 4581 directory. Especially useful in combination with -runas. 4582ERST 4583 4584#ifndef _WIN32 4585DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4586 "-runas user change to user id user just before starting the VM\n" \ 4587 " user can be numeric uid:gid instead\n", 4588 QEMU_ARCH_ALL) 4589#endif 4590SRST 4591``-runas user`` 4592 Immediately before starting guest execution, drop root privileges, 4593 switching to the specified user. 4594ERST 4595 4596DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4597 "-prom-env variable=value\n" 4598 " set OpenBIOS nvram variables\n", 4599 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4600SRST 4601``-prom-env variable=value`` 4602 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4603 4604 :: 4605 4606 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4607 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4608 4609 :: 4610 4611 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4612 -prom-env 'boot-device=hd:2,\yaboot' \ 4613 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4614ERST 4615DEF("semihosting", 0, QEMU_OPTION_semihosting, 4616 "-semihosting semihosting mode\n", 4617 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4618 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4619SRST 4620``-semihosting`` 4621 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4622 4623 Note that this allows guest direct access to the host filesystem, so 4624 should only be used with a trusted guest OS. 4625 4626 See the -semihosting-config option documentation for further 4627 information about the facilities this enables. 4628ERST 4629DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4630 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4631 " semihosting configuration\n", 4632QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4633QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4634SRST 4635``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4636 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4637 only). 4638 4639 Note that this allows guest direct access to the host filesystem, so 4640 should only be used with a trusted guest OS. 4641 4642 On Arm this implements the standard semihosting API, version 2.0. 4643 4644 On M68K this implements the "ColdFire GDB" interface used by 4645 libgloss. 4646 4647 Xtensa semihosting provides basic file IO calls, such as 4648 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4649 linux platform "sim" use this interface. 4650 4651 On RISC-V this implements the standard semihosting API, version 0.2. 4652 4653 ``target=native|gdb|auto`` 4654 Defines where the semihosting calls will be addressed, to QEMU 4655 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4656 means ``gdb`` during debug sessions and ``native`` otherwise. 4657 4658 ``chardev=str1`` 4659 Send the output to a chardev backend output for native or auto 4660 output when not in gdb 4661 4662 ``arg=str1,arg=str2,...`` 4663 Allows the user to pass input arguments, and can be used 4664 multiple times to build up a list. The old-style 4665 ``-kernel``/``-append`` method of passing a command line is 4666 still supported for backward compatibility. If both the 4667 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4668 specified, the former is passed to semihosting as it always 4669 takes precedence. 4670ERST 4671DEF("old-param", 0, QEMU_OPTION_old_param, 4672 "-old-param old param mode\n", QEMU_ARCH_ARM) 4673SRST 4674``-old-param`` 4675 Old param mode (ARM only). 4676ERST 4677 4678DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4679 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4680 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4681 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4682 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4683 " by the kernel, but typically no longer used by modern\n" \ 4684 " C library implementations.\n" \ 4685 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4686 " to elevate privileges using set*uid|gid system calls.\n" \ 4687 " The value 'children' will deny set*uid|gid system calls for\n" \ 4688 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4689 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4690 " blocking *fork and execve\n" \ 4691 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4692 QEMU_ARCH_ALL) 4693SRST 4694``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4695 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4696 filtering and 'off' will disable it. The default is 'off'. 4697 4698 ``obsolete=string`` 4699 Enable Obsolete system calls 4700 4701 ``elevateprivileges=string`` 4702 Disable set\*uid\|gid system calls 4703 4704 ``spawn=string`` 4705 Disable \*fork and execve 4706 4707 ``resourcecontrol=string`` 4708 Disable process affinity and schedular priority 4709ERST 4710 4711DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4712 "-readconfig <file>\n" 4713 " read config file\n", QEMU_ARCH_ALL) 4714SRST 4715``-readconfig file`` 4716 Read device configuration from file. This approach is useful when 4717 you want to spawn QEMU process with many command line options but 4718 you don't want to exceed the command line character limit. 4719ERST 4720 4721DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4722 "-no-user-config\n" 4723 " do not load default user-provided config files at startup\n", 4724 QEMU_ARCH_ALL) 4725SRST 4726``-no-user-config`` 4727 The ``-no-user-config`` option makes QEMU not load any of the 4728 user-provided config files on sysconfdir. 4729ERST 4730 4731DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4732 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4733 " specify tracing options\n", 4734 QEMU_ARCH_ALL) 4735SRST 4736``-trace [[enable=]pattern][,events=file][,file=file]`` 4737 .. include:: ../qemu-option-trace.rst.inc 4738 4739ERST 4740DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4741 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4742 " load a plugin\n", 4743 QEMU_ARCH_ALL) 4744SRST 4745``-plugin file=file[,argname=argvalue]`` 4746 Load a plugin. 4747 4748 ``file=file`` 4749 Load the given plugin from a shared library file. 4750 4751 ``argname=argvalue`` 4752 Argument passed to the plugin. (Can be given multiple times.) 4753ERST 4754 4755HXCOMM Internal use 4756DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4757DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4758 4759DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4760 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4761 " control error message format\n" 4762 " timestamp=on enables timestamps (default: off)\n" 4763 " guest-name=on enables guest name prefix but only if\n" 4764 " -name guest option is set (default: off)\n", 4765 QEMU_ARCH_ALL) 4766SRST 4767``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4768 Control error message format. 4769 4770 ``timestamp=on|off`` 4771 Prefix messages with a timestamp. Default is off. 4772 4773 ``guest-name=on|off`` 4774 Prefix messages with guest name but only if -name guest option is set 4775 otherwise the option is ignored. Default is off. 4776ERST 4777 4778DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4779 "-dump-vmstate <file>\n" 4780 " Output vmstate information in JSON format to file.\n" 4781 " Use the scripts/vmstate-static-checker.py file to\n" 4782 " check for possible regressions in migration code\n" 4783 " by comparing two such vmstate dumps.\n", 4784 QEMU_ARCH_ALL) 4785SRST 4786``-dump-vmstate file`` 4787 Dump json-encoded vmstate information for current machine type to 4788 file in file 4789ERST 4790 4791DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4792 "-enable-sync-profile\n" 4793 " enable synchronization profiling\n", 4794 QEMU_ARCH_ALL) 4795SRST 4796``-enable-sync-profile`` 4797 Enable synchronization profiling. 4798ERST 4799 4800DEFHEADING() 4801 4802DEFHEADING(Generic object creation:) 4803 4804DEF("object", HAS_ARG, QEMU_OPTION_object, 4805 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4806 " create a new object of type TYPENAME setting properties\n" 4807 " in the order they are specified. Note that the 'id'\n" 4808 " property must be set. These objects are placed in the\n" 4809 " '/objects' path.\n", 4810 QEMU_ARCH_ALL) 4811SRST 4812``-object typename[,prop1=value1,...]`` 4813 Create a new object of type typename setting properties in the order 4814 they are specified. Note that the 'id' property must be set. These 4815 objects are placed in the '/objects' path. 4816 4817 ``-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`` 4818 Creates a memory file backend object, which can be used to back 4819 the guest RAM with huge pages. 4820 4821 The ``id`` parameter is a unique ID that will be used to 4822 reference this memory region in other parameters, e.g. ``-numa``, 4823 ``-device nvdimm``, etc. 4824 4825 The ``size`` option provides the size of the memory region, and 4826 accepts common suffixes, e.g. ``500M``. 4827 4828 The ``mem-path`` provides the path to either a shared memory or 4829 huge page filesystem mount. 4830 4831 The ``share`` boolean option determines whether the memory 4832 region is marked as private to QEMU, or shared. The latter 4833 allows a co-operating external process to access the QEMU memory 4834 region. 4835 4836 The ``share`` is also required for pvrdma devices due to 4837 limitations in the RDMA API provided by Linux. 4838 4839 Setting share=on might affect the ability to configure NUMA 4840 bindings for the memory backend under some circumstances, see 4841 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4842 source tree for additional details. 4843 4844 Setting the ``discard-data`` boolean option to on indicates that 4845 file contents can be destroyed when QEMU exits, to avoid 4846 unnecessarily flushing data to the backing file. Note that 4847 ``discard-data`` is only an optimization, and QEMU might not 4848 discard file contents if it aborts unexpectedly or is terminated 4849 using SIGKILL. 4850 4851 The ``merge`` boolean option enables memory merge, also known as 4852 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4853 the pages for memory deduplication. 4854 4855 Setting the ``dump`` boolean option to off excludes the memory 4856 from core dumps. This feature is also known as MADV\_DONTDUMP. 4857 4858 The ``prealloc`` boolean option enables memory preallocation. 4859 4860 The ``host-nodes`` option binds the memory range to a list of 4861 NUMA host nodes. 4862 4863 The ``policy`` option sets the NUMA policy to one of the 4864 following values: 4865 4866 ``default`` 4867 default host policy 4868 4869 ``preferred`` 4870 prefer the given host node list for allocation 4871 4872 ``bind`` 4873 restrict memory allocation to the given host node list 4874 4875 ``interleave`` 4876 interleave memory allocations across the given host node 4877 list 4878 4879 The ``align`` option specifies the base address alignment when 4880 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4881 ``2M``. Some backend store specified by ``mem-path`` requires an 4882 alignment different than the default one used by QEMU, eg the 4883 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4884 such cases, users can specify the required alignment via this 4885 option. 4886 4887 The ``pmem`` option specifies whether the backing file specified 4888 by ``mem-path`` is in host persistent memory that can be 4889 accessed using the SNIA NVM programming model (e.g. Intel 4890 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4891 operations to guarantee the persistence of its own writes to 4892 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4893 migration). Also, we will map the backend-file with MAP\_SYNC 4894 flag, which ensures the file metadata is in sync for 4895 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4896 requires support from both the host kernel (since Linux kernel 4897 4.15) and the filesystem of ``mem-path`` mounted with DAX 4898 option. 4899 4900 The ``readonly`` option specifies whether the backing file is opened 4901 read-only or read-write (default). 4902 4903 ``-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`` 4904 Creates a memory backend object, which can be used to back the 4905 guest RAM. Memory backend objects offer more control than the 4906 ``-m`` option that is traditionally used to define guest RAM. 4907 Please refer to ``memory-backend-file`` for a description of the 4908 options. 4909 4910 ``-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`` 4911 Creates an anonymous memory file backend object, which allows 4912 QEMU to share the memory with an external process (e.g. when 4913 using vhost-user). The memory is allocated with memfd and 4914 optional sealing. (Linux only) 4915 4916 The ``seal`` option creates a sealed-file, that will block 4917 further resizing the memory ('on' by default). 4918 4919 The ``hugetlb`` option specify the file to be created resides in 4920 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4921 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4922 the hugetlb page size on systems that support multiple hugetlb 4923 page sizes (it must be a power of 2 value supported by the 4924 system). 4925 4926 In some versions of Linux, the ``hugetlb`` option is 4927 incompatible with the ``seal`` option (requires at least Linux 4928 4.16). 4929 4930 Please refer to ``memory-backend-file`` for a description of the 4931 other options. 4932 4933 The ``share`` boolean option is on by default with memfd. 4934 4935 ``-object rng-builtin,id=id`` 4936 Creates a random number generator backend which obtains entropy 4937 from QEMU builtin functions. The ``id`` parameter is a unique ID 4938 that will be used to reference this entropy backend from the 4939 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4940 uses this RNG backend. 4941 4942 ``-object rng-random,id=id,filename=/dev/random`` 4943 Creates a random number generator backend which obtains entropy 4944 from a device on the host. The ``id`` parameter is a unique ID 4945 that will be used to reference this entropy backend from the 4946 ``virtio-rng`` device. The ``filename`` parameter specifies 4947 which file to obtain entropy from and if omitted defaults to 4948 ``/dev/urandom``. 4949 4950 ``-object rng-egd,id=id,chardev=chardevid`` 4951 Creates a random number generator backend which obtains entropy 4952 from an external daemon running on the host. The ``id`` 4953 parameter is a unique ID that will be used to reference this 4954 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4955 parameter is the unique ID of a character device backend that 4956 provides the connection to the RNG daemon. 4957 4958 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4959 Creates a TLS anonymous credentials object, which can be used to 4960 provide TLS support on network backends. The ``id`` parameter is 4961 a unique ID which network backends will use to access the 4962 credentials. The ``endpoint`` is either ``server`` or ``client`` 4963 depending on whether the QEMU network backend that uses the 4964 credentials will be acting as a client or as a server. If 4965 ``verify-peer`` is enabled (the default) then once the handshake 4966 is completed, the peer credentials will be verified, though this 4967 is a no-op for anonymous credentials. 4968 4969 The dir parameter tells QEMU where to find the credential files. 4970 For server endpoints, this directory may contain a file 4971 dh-params.pem providing diffie-hellman parameters to use for the 4972 TLS server. If the file is missing, QEMU will generate a set of 4973 DH parameters at startup. This is a computationally expensive 4974 operation that consumes random pool entropy, so it is 4975 recommended that a persistent set of parameters be generated 4976 upfront and saved. 4977 4978 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4979 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4980 can be used to provide TLS support on network backends. The 4981 ``id`` parameter is a unique ID which network backends will use 4982 to access the credentials. The ``endpoint`` is either ``server`` 4983 or ``client`` depending on whether the QEMU network backend that 4984 uses the credentials will be acting as a client or as a server. 4985 For clients only, ``username`` is the username which will be 4986 sent to the server. If omitted it defaults to "qemu". 4987 4988 The dir parameter tells QEMU where to find the keys file. It is 4989 called "dir/keys.psk" and contains "username:key" pairs. This 4990 file can most easily be created using the GnuTLS ``psktool`` 4991 program. 4992 4993 For server endpoints, dir may also contain a file dh-params.pem 4994 providing diffie-hellman parameters to use for the TLS server. 4995 If the file is missing, QEMU will generate a set of DH 4996 parameters at startup. This is a computationally expensive 4997 operation that consumes random pool entropy, so it is 4998 recommended that a persistent set of parameters be generated up 4999 front and saved. 5000 5001 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5002 Creates a TLS anonymous credentials object, which can be used to 5003 provide TLS support on network backends. The ``id`` parameter is 5004 a unique ID which network backends will use to access the 5005 credentials. The ``endpoint`` is either ``server`` or ``client`` 5006 depending on whether the QEMU network backend that uses the 5007 credentials will be acting as a client or as a server. If 5008 ``verify-peer`` is enabled (the default) then once the handshake 5009 is completed, the peer credentials will be verified. With x509 5010 certificates, this implies that the clients must be provided 5011 with valid client certificates too. 5012 5013 The dir parameter tells QEMU where to find the credential files. 5014 For server endpoints, this directory may contain a file 5015 dh-params.pem providing diffie-hellman parameters to use for the 5016 TLS server. If the file is missing, QEMU will generate a set of 5017 DH parameters at startup. This is a computationally expensive 5018 operation that consumes random pool entropy, so it is 5019 recommended that a persistent set of parameters be generated 5020 upfront and saved. 5021 5022 For x509 certificate credentials the directory will contain 5023 further files providing the x509 certificates. The certificates 5024 must be stored in PEM format, in filenames ca-cert.pem, 5025 ca-crl.pem (optional), server-cert.pem (only servers), 5026 server-key.pem (only servers), client-cert.pem (only clients), 5027 and client-key.pem (only clients). 5028 5029 For the server-key.pem and client-key.pem files which contain 5030 sensitive private keys, it is possible to use an encrypted 5031 version by providing the passwordid parameter. This provides the 5032 ID of a previously created ``secret`` object containing the 5033 password for decryption. 5034 5035 The priority parameter allows to override the global default 5036 priority used by gnutls. This can be useful if the system 5037 administrator needs to use a weaker set of crypto priorities for 5038 QEMU without potentially forcing the weakness onto all 5039 applications. Or conversely if one wants wants a stronger 5040 default for QEMU than for all other applications, they can do 5041 this through this parameter. Its format is a gnutls priority 5042 string as described at 5043 https://gnutls.org/manual/html_node/Priority-Strings.html. 5044 5045 ``-object tls-cipher-suites,id=id,priority=priority`` 5046 Creates a TLS cipher suites object, which can be used to control 5047 the TLS cipher/protocol algorithms that applications are permitted 5048 to use. 5049 5050 The ``id`` parameter is a unique ID which frontends will use to 5051 access the ordered list of permitted TLS cipher suites from the 5052 host. 5053 5054 The ``priority`` parameter allows to override the global default 5055 priority used by gnutls. This can be useful if the system 5056 administrator needs to use a weaker set of crypto priorities for 5057 QEMU without potentially forcing the weakness onto all 5058 applications. Or conversely if one wants wants a stronger 5059 default for QEMU than for all other applications, they can do 5060 this through this parameter. Its format is a gnutls priority 5061 string as described at 5062 https://gnutls.org/manual/html_node/Priority-Strings.html. 5063 5064 An example of use of this object is to control UEFI HTTPS Boot. 5065 The tls-cipher-suites object exposes the ordered list of permitted 5066 TLS cipher suites from the host side to the guest firmware, via 5067 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5068 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5069 guest-side TLS. 5070 5071 In the following example, the priority at which the host-side policy 5072 is retrieved is given by the ``priority`` property. 5073 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5074 refer to /etc/crypto-policies/back-ends/gnutls.config. 5075 5076 .. parsed-literal:: 5077 5078 # |qemu_system| \\ 5079 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5080 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5081 5082 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5083 Interval t can't be 0, this filter batches the packet delivery: 5084 all packets arriving in a given interval on netdev netdevid are 5085 delayed until the end of the interval. Interval is in 5086 microseconds. ``status`` is optional that indicate whether the 5087 netfilter is on (enabled) or off (disabled), the default status 5088 for netfilter will be 'on'. 5089 5090 queue all\|rx\|tx is an option that can be applied to any 5091 netfilter. 5092 5093 ``all``: the filter is attached both to the receive and the 5094 transmit queue of the netdev (default). 5095 5096 ``rx``: the filter is attached to the receive queue of the 5097 netdev, where it will receive packets sent to the netdev. 5098 5099 ``tx``: the filter is attached to the transmit queue of the 5100 netdev, where it will receive packets sent by the netdev. 5101 5102 position head\|tail\|id=<id> is an option to specify where the 5103 filter should be inserted in the filter list. It can be applied 5104 to any netfilter. 5105 5106 ``head``: the filter is inserted at the head of the filter list, 5107 before any existing filters. 5108 5109 ``tail``: the filter is inserted at the tail of the filter list, 5110 behind any existing filters (default). 5111 5112 ``id=<id>``: the filter is inserted before or behind the filter 5113 specified by <id>, see the insert option below. 5114 5115 insert behind\|before is an option to specify where to insert 5116 the new filter relative to the one specified with 5117 position=id=<id>. It can be applied to any netfilter. 5118 5119 ``before``: insert before the specified filter. 5120 5121 ``behind``: insert behind the specified filter (default). 5122 5123 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5124 filter-mirror on netdev netdevid,mirror net packet to 5125 chardevchardevid, if it has the vnet\_hdr\_support flag, 5126 filter-mirror will mirror packet with vnet\_hdr\_len. 5127 5128 ``-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]`` 5129 filter-redirector on netdev netdevid,redirect filter's net 5130 packet to chardev chardevid,and redirect indev's packet to 5131 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5132 will redirect packet with vnet\_hdr\_len. Create a 5133 filter-redirector we need to differ outdev id from indev id, id 5134 can not be the same. we can just use indev or outdev, but at 5135 least one of indev or outdev need to be specified. 5136 5137 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5138 Filter-rewriter is a part of COLO project.It will rewrite tcp 5139 packet to secondary from primary to keep secondary tcp 5140 connection,and rewrite tcp packet to primary from secondary make 5141 tcp packet can be handled by client.if it has the 5142 vnet\_hdr\_support flag, we can parse packet with vnet header. 5143 5144 usage: colo secondary: -object 5145 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5146 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5147 filter-rewriter,id=rew0,netdev=hn0,queue=all 5148 5149 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5150 Dump the network traffic on netdev dev to the file specified by 5151 filename. At most len bytes (64k by default) per packet are 5152 stored. The file format is libpcap, so it can be analyzed with 5153 tools such as tcpdump or Wireshark. 5154 5155 ``-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}]`` 5156 Colo-compare gets packet from primary\_in chardevid and 5157 secondary\_in, then compare whether the payload of primary packet 5158 and secondary packet are the same. If same, it will output 5159 primary packet to out\_dev, else it will notify COLO-framework to do 5160 checkpoint and send primary packet to out\_dev. In order to 5161 improve efficiency, we need to put the task of comparison in 5162 another iothread. If it has the vnet\_hdr\_support flag, 5163 colo compare will send/recv packet with vnet\_hdr\_len. 5164 The compare\_timeout=@var{ms} determines the maximum time of the 5165 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5166 is to set the period of scanning expired primary node network packets. 5167 The max\_queue\_size=@var{size} is to set the max compare queue 5168 size depend on user environment. 5169 If user want to use Xen COLO, need to add the notify\_dev to 5170 notify Xen colo-frame to do checkpoint. 5171 5172 COLO-compare must be used with the help of filter-mirror, 5173 filter-redirector and filter-rewriter. 5174 5175 :: 5176 5177 KVM COLO 5178 5179 primary: 5180 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5181 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5182 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5183 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5184 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5185 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5186 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5187 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5188 -object iothread,id=iothread1 5189 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5190 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5191 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5192 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5193 5194 secondary: 5195 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5196 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5197 -chardev socket,id=red0,host=3.3.3.3,port=9003 5198 -chardev socket,id=red1,host=3.3.3.3,port=9004 5199 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5200 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5201 5202 5203 Xen COLO 5204 5205 primary: 5206 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5207 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5208 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5209 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5210 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5211 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5212 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5213 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5214 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5215 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5216 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5217 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5218 -object iothread,id=iothread1 5219 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5220 5221 secondary: 5222 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5223 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5224 -chardev socket,id=red0,host=3.3.3.3,port=9003 5225 -chardev socket,id=red1,host=3.3.3.3,port=9004 5226 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5227 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5228 5229 If you want to know the detail of above command line, you can 5230 read the colo-compare git log. 5231 5232 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5233 Creates a cryptodev backend which executes crypto opreation from 5234 the QEMU cipher APIS. The id parameter is a unique ID that will 5235 be used to reference this cryptodev backend from the 5236 ``virtio-crypto`` device. The queues parameter is optional, 5237 which specify the queue number of cryptodev backend, the default 5238 of queues is 1. 5239 5240 .. parsed-literal:: 5241 5242 # |qemu_system| \\ 5243 [...] \\ 5244 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5245 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5246 [...] 5247 5248 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5249 Creates a vhost-user cryptodev backend, backed by a chardev 5250 chardevid. The id parameter is a unique ID that will be used to 5251 reference this cryptodev backend from the ``virtio-crypto`` 5252 device. The chardev should be a unix domain socket backed one. 5253 The vhost-user uses a specifically defined protocol to pass 5254 vhost ioctl replacement messages to an application on the other 5255 end of the socket. The queues parameter is optional, which 5256 specify the queue number of cryptodev backend for multiqueue 5257 vhost-user, the default of queues is 1. 5258 5259 .. parsed-literal:: 5260 5261 # |qemu_system| \\ 5262 [...] \\ 5263 -chardev socket,id=chardev0,path=/path/to/socket \\ 5264 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5265 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5266 [...] 5267 5268 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5269 \ 5270 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5271 Defines a secret to store a password, encryption key, or some 5272 other sensitive data. The sensitive data can either be passed 5273 directly via the data parameter, or indirectly via the file 5274 parameter. Using the data parameter is insecure unless the 5275 sensitive data is encrypted. 5276 5277 The sensitive data can be provided in raw format (the default), 5278 or base64. When encoded as JSON, the raw format only supports 5279 valid UTF-8 characters, so base64 is recommended for sending 5280 binary data. QEMU will convert from which ever format is 5281 provided to the format it needs internally. eg, an RBD password 5282 can be provided in raw format, even though it will be base64 5283 encoded when passed onto the RBD sever. 5284 5285 For added protection, it is possible to encrypt the data 5286 associated with a secret using the AES-256-CBC cipher. Use of 5287 encryption is indicated by providing the keyid and iv 5288 parameters. The keyid parameter provides the ID of a previously 5289 defined secret that contains the AES-256 decryption key. This 5290 key should be 32-bytes long and be base64 encoded. The iv 5291 parameter provides the random initialization vector used for 5292 encryption of this particular secret and should be a base64 5293 encrypted string of the 16-byte IV. 5294 5295 The simplest (insecure) usage is to provide the secret inline 5296 5297 .. parsed-literal:: 5298 5299 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5300 5301 The simplest secure usage is to provide the secret via a file 5302 5303 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5304 secret,id=sec0,file=mypasswd.txt,format=raw 5305 5306 For greater security, AES-256-CBC should be used. To illustrate 5307 usage, consider the openssl command line tool which can encrypt 5308 the data. Note that when encrypting, the plaintext must be 5309 padded to the cipher block size (32 bytes) using the standard 5310 PKCS#5/6 compatible padding algorithm. 5311 5312 First a master key needs to be created in base64 encoding: 5313 5314 :: 5315 5316 # openssl rand -base64 32 > key.b64 5317 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5318 5319 Each secret to be encrypted needs to have a random 5320 initialization vector generated. These do not need to be kept 5321 secret 5322 5323 :: 5324 5325 # openssl rand -base64 16 > iv.b64 5326 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5327 5328 The secret to be defined can now be encrypted, in this case 5329 we're telling openssl to base64 encode the result, but it could 5330 be left as raw bytes if desired. 5331 5332 :: 5333 5334 # SECRET=$(printf "letmein" | 5335 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5336 5337 When launching QEMU, create a master secret pointing to 5338 ``key.b64`` and specify that to be used to decrypt the user 5339 password. Pass the contents of ``iv.b64`` to the second secret 5340 5341 .. parsed-literal:: 5342 5343 # |qemu_system| \\ 5344 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5345 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5346 data=$SECRET,iv=$(<iv.b64) 5347 5348 ``-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]`` 5349 Create a Secure Encrypted Virtualization (SEV) guest object, 5350 which can be used to provide the guest memory encryption support 5351 on AMD processors. 5352 5353 When memory encryption is enabled, one of the physical address 5354 bit (aka the C-bit) is utilized to mark if a memory page is 5355 protected. The ``cbitpos`` is used to provide the C-bit 5356 position. The C-bit position is Host family dependent hence user 5357 must provide this value. On EPYC, the value should be 47. 5358 5359 When memory encryption is enabled, we loose certain bits in 5360 physical address space. The ``reduced-phys-bits`` is used to 5361 provide the number of bits we loose in physical address space. 5362 Similar to C-bit, the value is Host family dependent. On EPYC, 5363 the value should be 5. 5364 5365 The ``sev-device`` provides the device file to use for 5366 communicating with the SEV firmware running inside AMD Secure 5367 Processor. The default device is '/dev/sev'. If hardware 5368 supports memory encryption then /dev/sev devices are created by 5369 CCP driver. 5370 5371 The ``policy`` provides the guest policy to be enforced by the 5372 SEV firmware and restrict what configuration and operational 5373 commands can be performed on this guest by the hypervisor. The 5374 policy should be provided by the guest owner and is bound to the 5375 guest and cannot be changed throughout the lifetime of the 5376 guest. The default is 0. 5377 5378 If guest ``policy`` allows sharing the key with another SEV 5379 guest then ``handle`` can be use to provide handle of the guest 5380 from which to share the key. 5381 5382 The ``dh-cert-file`` and ``session-file`` provides the guest 5383 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5384 and session parameters are used for establishing a cryptographic 5385 session with the guest owner to negotiate keys used for 5386 attestation. The file must be encoded in base64. 5387 5388 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5389 cmdline to a designated guest firmware page for measured Linux 5390 boot with -kernel. The default is off. (Since 6.2) 5391 5392 e.g to launch a SEV guest 5393 5394 .. parsed-literal:: 5395 5396 # |qemu_system_x86| \\ 5397 ...... \\ 5398 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5399 -machine ...,memory-encryption=sev0 \\ 5400 ..... 5401 5402 ``-object authz-simple,id=id,identity=string`` 5403 Create an authorization object that will control access to 5404 network services. 5405 5406 The ``identity`` parameter is identifies the user and its format 5407 depends on the network service that authorization object is 5408 associated with. For authorizing based on TLS x509 certificates, 5409 the identity must be the x509 distinguished name. Note that care 5410 must be taken to escape any commas in the distinguished name. 5411 5412 An example authorization object to validate a x509 distinguished 5413 name would look like: 5414 5415 .. parsed-literal:: 5416 5417 # |qemu_system| \\ 5418 ... \\ 5419 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5420 ... 5421 5422 Note the use of quotes due to the x509 distinguished name 5423 containing whitespace, and escaping of ','. 5424 5425 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5426 Create an authorization object that will control access to 5427 network services. 5428 5429 The ``filename`` parameter is the fully qualified path to a file 5430 containing the access control list rules in JSON format. 5431 5432 An example set of rules that match against SASL usernames might 5433 look like: 5434 5435 :: 5436 5437 { 5438 "rules": [ 5439 { "match": "fred", "policy": "allow", "format": "exact" }, 5440 { "match": "bob", "policy": "allow", "format": "exact" }, 5441 { "match": "danb", "policy": "deny", "format": "glob" }, 5442 { "match": "dan*", "policy": "allow", "format": "exact" }, 5443 ], 5444 "policy": "deny" 5445 } 5446 5447 When checking access the object will iterate over all the rules 5448 and the first rule to match will have its ``policy`` value 5449 returned as the result. If no rules match, then the default 5450 ``policy`` value is returned. 5451 5452 The rules can either be an exact string match, or they can use 5453 the simple UNIX glob pattern matching to allow wildcards to be 5454 used. 5455 5456 If ``refresh`` is set to true the file will be monitored and 5457 automatically reloaded whenever its content changes. 5458 5459 As with the ``authz-simple`` object, the format of the identity 5460 strings being matched depends on the network service, but is 5461 usually a TLS x509 distinguished name, or a SASL username. 5462 5463 An example authorization object to validate a SASL username 5464 would look like: 5465 5466 .. parsed-literal:: 5467 5468 # |qemu_system| \\ 5469 ... \\ 5470 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5471 ... 5472 5473 ``-object authz-pam,id=id,service=string`` 5474 Create an authorization object that will control access to 5475 network services. 5476 5477 The ``service`` parameter provides the name of a PAM service to 5478 use for authorization. It requires that a file 5479 ``/etc/pam.d/service`` exist to provide the configuration for 5480 the ``account`` subsystem. 5481 5482 An example authorization object to validate a TLS x509 5483 distinguished name would look like: 5484 5485 .. parsed-literal:: 5486 5487 # |qemu_system| \\ 5488 ... \\ 5489 -object authz-pam,id=auth0,service=qemu-vnc \\ 5490 ... 5491 5492 There would then be a corresponding config file for PAM at 5493 ``/etc/pam.d/qemu-vnc`` that contains: 5494 5495 :: 5496 5497 account requisite pam_listfile.so item=user sense=allow \ 5498 file=/etc/qemu/vnc.allow 5499 5500 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5501 of x509 distingished names that are permitted access 5502 5503 :: 5504 5505 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5506 5507 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5508 Creates a dedicated event loop thread that devices can be 5509 assigned to. This is known as an IOThread. By default device 5510 emulation happens in vCPU threads or the main event loop thread. 5511 This can become a scalability bottleneck. IOThreads allow device 5512 emulation and I/O to run on other host CPUs. 5513 5514 The ``id`` parameter is a unique ID that will be used to 5515 reference this IOThread from ``-device ...,iothread=id``. 5516 Multiple devices can be assigned to an IOThread. Note that not 5517 all devices support an ``iothread`` parameter. 5518 5519 The ``query-iothreads`` QMP command lists IOThreads and reports 5520 their thread IDs so that the user can configure host CPU 5521 pinning/affinity. 5522 5523 IOThreads use an adaptive polling algorithm to reduce event loop 5524 latency. Instead of entering a blocking system call to monitor 5525 file descriptors and then pay the cost of being woken up when an 5526 event occurs, the polling algorithm spins waiting for events for 5527 a short time. The algorithm's default parameters are suitable 5528 for many cases but can be adjusted based on knowledge of the 5529 workload and/or host device latency. 5530 5531 The ``poll-max-ns`` parameter is the maximum number of 5532 nanoseconds to busy wait for events. Polling can be disabled by 5533 setting this value to 0. 5534 5535 The ``poll-grow`` parameter is the multiplier used to increase 5536 the polling time when the algorithm detects it is missing events 5537 due to not polling long enough. 5538 5539 The ``poll-shrink`` parameter is the divisor used to decrease 5540 the polling time when the algorithm detects it is spending too 5541 long polling without encountering events. 5542 5543 The ``aio-max-batch`` parameter is the maximum number of requests 5544 in a batch for the AIO engine, 0 means that the engine will use 5545 its default. 5546 5547 The IOThread parameters can be modified at run-time using the 5548 ``qom-set`` command (where ``iothread1`` is the IOThread's 5549 ``id``): 5550 5551 :: 5552 5553 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5554ERST 5555 5556 5557HXCOMM This is the last statement. Insert new options before this line! 5558 5559#undef DEF 5560#undef DEFHEADING 5561#undef ARCHHEADING 5562
