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