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 driver option is the same as with the corresponding ``-audiodev`` option below. 708 The guest hardware model can be set with ``model=modelname``. 709 710 Use ``driver=help`` to list the available drivers, 711 and ``model=help`` to list the available device types. 712 713 The following two example do exactly the same, to show how ``-audio`` 714 can be used to shorten the command line length: 715 716 .. parsed-literal:: 717 718 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 719 |qemu_system| -audio pa,model=sb16 720ERST 721 722DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 723 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 724 " specifies the audio backend to use\n" 725 " Use ``-audiodev help`` to list the available drivers\n" 726 " id= identifier of the backend\n" 727 " timer-period= timer period in microseconds\n" 728 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 729 " in|out.fixed-settings= use fixed settings for host audio\n" 730 " in|out.frequency= frequency to use with fixed settings\n" 731 " in|out.channels= number of channels to use with fixed settings\n" 732 " in|out.format= sample format to use with fixed settings\n" 733 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 734 " in|out.voices= number of voices to use\n" 735 " in|out.buffer-length= length of buffer in microseconds\n" 736 "-audiodev none,id=id,[,prop[=value][,...]]\n" 737 " dummy driver that discards all output\n" 738#ifdef CONFIG_AUDIO_ALSA 739 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 740 " in|out.dev= name of the audio device to use\n" 741 " in|out.period-length= length of period in microseconds\n" 742 " in|out.try-poll= attempt to use poll mode\n" 743 " threshold= threshold (in microseconds) when playback starts\n" 744#endif 745#ifdef CONFIG_AUDIO_COREAUDIO 746 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 747 " in|out.buffer-count= number of buffers\n" 748#endif 749#ifdef CONFIG_AUDIO_DSOUND 750 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 751 " latency= add extra latency to playback in microseconds\n" 752#endif 753#ifdef CONFIG_AUDIO_OSS 754 "-audiodev oss,id=id[,prop[=value][,...]]\n" 755 " in|out.dev= path of the audio device to use\n" 756 " in|out.buffer-count= number of buffers\n" 757 " in|out.try-poll= attempt to use poll mode\n" 758 " try-mmap= try using memory mapped access\n" 759 " exclusive= open device in exclusive mode\n" 760 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 761#endif 762#ifdef CONFIG_AUDIO_PA 763 "-audiodev pa,id=id[,prop[=value][,...]]\n" 764 " server= PulseAudio server address\n" 765 " in|out.name= source/sink device name\n" 766 " in|out.latency= desired latency in microseconds\n" 767#endif 768#ifdef CONFIG_AUDIO_SDL 769 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 770 " in|out.buffer-count= number of buffers\n" 771#endif 772#ifdef CONFIG_AUDIO_SNDIO 773 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 774#endif 775#ifdef CONFIG_SPICE 776 "-audiodev spice,id=id[,prop[=value][,...]]\n" 777#endif 778#ifdef CONFIG_DBUS_DISPLAY 779 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 780#endif 781 "-audiodev wav,id=id[,prop[=value][,...]]\n" 782 " path= path of wav file to record\n", 783 QEMU_ARCH_ALL) 784SRST 785``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 786 Adds a new audio backend driver identified by id. There are global 787 and driver specific properties. Some values can be set differently 788 for input and output, they're marked with ``in|out.``. You can set 789 the input's property with ``in.prop`` and the output's property with 790 ``out.prop``. For example: 791 792 :: 793 794 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 795 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 796 797 NOTE: parameter validation is known to be incomplete, in many cases 798 specifying an invalid option causes QEMU to print an error message 799 and continue emulation without sound. 800 801 Valid global options are: 802 803 ``id=identifier`` 804 Identifies the audio backend. 805 806 ``timer-period=period`` 807 Sets the timer period used by the audio subsystem in 808 microseconds. Default is 10000 (10 ms). 809 810 ``in|out.mixing-engine=on|off`` 811 Use QEMU's mixing engine to mix all streams inside QEMU and 812 convert audio formats when not supported by the backend. When 813 off, fixed-settings must be off too. Note that disabling this 814 option means that the selected backend must support multiple 815 streams and the audio formats used by the virtual cards, 816 otherwise you'll get no sound. It's not recommended to disable 817 this option unless you want to use 5.1 or 7.1 audio, as mixing 818 engine only supports mono and stereo audio. Default is on. 819 820 ``in|out.fixed-settings=on|off`` 821 Use fixed settings for host audio. When off, it will change 822 based on how the guest opens the sound card. In this case you 823 must not specify frequency, channels or format. Default is on. 824 825 ``in|out.frequency=frequency`` 826 Specify the frequency to use when using fixed-settings. Default 827 is 44100Hz. 828 829 ``in|out.channels=channels`` 830 Specify the number of channels to use when using fixed-settings. 831 Default is 2 (stereo). 832 833 ``in|out.format=format`` 834 Specify the sample format to use when using fixed-settings. 835 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 836 ``u32``, ``f32``. Default is ``s16``. 837 838 ``in|out.voices=voices`` 839 Specify the number of voices to use. Default is 1. 840 841 ``in|out.buffer-length=usecs`` 842 Sets the size of the buffer in microseconds. 843 844``-audiodev none,id=id[,prop[=value][,...]]`` 845 Creates a dummy backend that discards all outputs. This backend has 846 no backend specific properties. 847 848``-audiodev alsa,id=id[,prop[=value][,...]]`` 849 Creates backend using the ALSA. This backend is only available on 850 Linux. 851 852 ALSA specific options are: 853 854 ``in|out.dev=device`` 855 Specify the ALSA device to use for input and/or output. Default 856 is ``default``. 857 858 ``in|out.period-length=usecs`` 859 Sets the period length in microseconds. 860 861 ``in|out.try-poll=on|off`` 862 Attempt to use poll mode with the device. Default is on. 863 864 ``threshold=threshold`` 865 Threshold (in microseconds) when playback starts. Default is 0. 866 867``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 868 Creates a backend using Apple's Core Audio. This backend is only 869 available on Mac OS and only supports playback. 870 871 Core Audio specific options are: 872 873 ``in|out.buffer-count=count`` 874 Sets the count of the buffers. 875 876``-audiodev dsound,id=id[,prop[=value][,...]]`` 877 Creates a backend using Microsoft's DirectSound. This backend is 878 only available on Windows and only supports playback. 879 880 DirectSound specific options are: 881 882 ``latency=usecs`` 883 Add extra usecs microseconds latency to playback. Default is 884 10000 (10 ms). 885 886``-audiodev oss,id=id[,prop[=value][,...]]`` 887 Creates a backend using OSS. This backend is available on most 888 Unix-like systems. 889 890 OSS specific options are: 891 892 ``in|out.dev=device`` 893 Specify the file name of the OSS device to use. Default is 894 ``/dev/dsp``. 895 896 ``in|out.buffer-count=count`` 897 Sets the count of the buffers. 898 899 ``in|out.try-poll=on|of`` 900 Attempt to use poll mode with the device. Default is on. 901 902 ``try-mmap=on|off`` 903 Try using memory mapped device access. Default is off. 904 905 ``exclusive=on|off`` 906 Open the device in exclusive mode (vmix won't work in this 907 case). Default is off. 908 909 ``dsp-policy=policy`` 910 Sets the timing policy (between 0 and 10, where smaller number 911 means smaller latency but higher CPU usage). Use -1 to use 912 buffer sizes specified by ``buffer`` and ``buffer-count``. This 913 option is ignored if you do not have OSS 4. Default is 5. 914 915``-audiodev pa,id=id[,prop[=value][,...]]`` 916 Creates a backend using PulseAudio. This backend is available on 917 most systems. 918 919 PulseAudio specific options are: 920 921 ``server=server`` 922 Sets the PulseAudio server to connect to. 923 924 ``in|out.name=sink`` 925 Use the specified source/sink for recording/playback. 926 927 ``in|out.latency=usecs`` 928 Desired latency in microseconds. The PulseAudio server will try 929 to honor this value but actual latencies may be lower or higher. 930 931``-audiodev sdl,id=id[,prop[=value][,...]]`` 932 Creates a backend using SDL. This backend is available on most 933 systems, but you should use your platform's native backend if 934 possible. 935 936 SDL specific options are: 937 938 ``in|out.buffer-count=count`` 939 Sets the count of the buffers. 940 941``-audiodev sndio,id=id[,prop[=value][,...]]`` 942 Creates a backend using SNDIO. This backend is available on 943 OpenBSD and most other Unix-like systems. 944 945 Sndio specific options are: 946 947 ``in|out.dev=device`` 948 Specify the sndio device to use for input and/or output. Default 949 is ``default``. 950 951 ``in|out.latency=usecs`` 952 Sets the desired period length in microseconds. 953 954``-audiodev spice,id=id[,prop[=value][,...]]`` 955 Creates a backend that sends audio through SPICE. This backend 956 requires ``-spice`` and automatically selected in that case, so 957 usually you can ignore this option. This backend has no backend 958 specific properties. 959 960``-audiodev wav,id=id[,prop[=value][,...]]`` 961 Creates a backend that writes audio to a WAV file. 962 963 Backend specific options are: 964 965 ``path=path`` 966 Write recorded audio into the specified file. Default is 967 ``qemu.wav``. 968ERST 969 970DEF("device", HAS_ARG, QEMU_OPTION_device, 971 "-device driver[,prop[=value][,...]]\n" 972 " add device (based on driver)\n" 973 " prop=value,... sets driver properties\n" 974 " use '-device help' to print all possible drivers\n" 975 " use '-device driver,help' to print all possible properties\n", 976 QEMU_ARCH_ALL) 977SRST 978``-device driver[,prop[=value][,...]]`` 979 Add device driver. prop=value sets driver properties. Valid 980 properties depend on the driver. To get help on possible drivers and 981 properties, use ``-device help`` and ``-device driver,help``. 982 983 Some drivers are: 984 985``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 986 Add an IPMI BMC. This is a simulation of a hardware management 987 interface processor that normally sits on a system. It provides a 988 watchdog and the ability to reset and power control the system. You 989 need to connect this to an IPMI interface to make it useful 990 991 The IPMI slave address to use for the BMC. The default is 0x20. This 992 address is the BMC's address on the I2C network of management 993 controllers. If you don't know what this means, it is safe to ignore 994 it. 995 996 ``id=id`` 997 The BMC id for interfaces to use this device. 998 999 ``slave_addr=val`` 1000 Define slave address to use for the BMC. The default is 0x20. 1001 1002 ``sdrfile=file`` 1003 file containing raw Sensor Data Records (SDR) data. The default 1004 is none. 1005 1006 ``fruareasize=val`` 1007 size of a Field Replaceable Unit (FRU) area. The default is 1008 1024. 1009 1010 ``frudatafile=file`` 1011 file containing raw Field Replaceable Unit (FRU) inventory data. 1012 The default is none. 1013 1014 ``guid=uuid`` 1015 value for the GUID for the BMC, in standard UUID format. If this 1016 is set, get "Get GUID" command to the BMC will return it. 1017 Otherwise "Get GUID" will return an error. 1018 1019``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1020 Add a connection to an external IPMI BMC simulator. Instead of 1021 locally emulating the BMC like the above item, instead connect to an 1022 external entity that provides the IPMI services. 1023 1024 A connection is made to an external BMC simulator. If you do this, 1025 it is strongly recommended that you use the "reconnect=" chardev 1026 option to reconnect to the simulator if the connection is lost. Note 1027 that if this is not used carefully, it can be a security issue, as 1028 the interface has the ability to send resets, NMIs, and power off 1029 the VM. It's best if QEMU makes a connection to an external 1030 simulator running on a secure port on localhost, so neither the 1031 simulator nor QEMU is exposed to any outside network. 1032 1033 See the "lanserv/README.vm" file in the OpenIPMI library for more 1034 details on the external interface. 1035 1036``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1037 Add a KCS IPMI interafce on the ISA bus. This also adds a 1038 corresponding ACPI and SMBIOS entries, if appropriate. 1039 1040 ``bmc=id`` 1041 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1042 above. 1043 1044 ``ioport=val`` 1045 Define the I/O address of the interface. The default is 0xca0 1046 for KCS. 1047 1048 ``irq=val`` 1049 Define the interrupt to use. The default is 5. To disable 1050 interrupts, set this to 0. 1051 1052``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1053 Like the KCS interface, but defines a BT interface. The default port 1054 is 0xe4 and the default interrupt is 5. 1055 1056``-device pci-ipmi-kcs,bmc=id`` 1057 Add a KCS IPMI interafce on the PCI bus. 1058 1059 ``bmc=id`` 1060 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1061 1062``-device pci-ipmi-bt,bmc=id`` 1063 Like the KCS interface, but defines a BT interface on the PCI bus. 1064 1065``-device intel-iommu[,option=...]`` 1066 This is only supported by ``-machine q35``, which will enable Intel VT-d 1067 emulation within the guest. It supports below options: 1068 1069 ``intremap=on|off`` (default: auto) 1070 This enables interrupt remapping feature. It's required to enable 1071 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1072 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1073 The default value is "auto", which will be decided by the mode of 1074 kernel-irqchip. 1075 1076 ``caching-mode=on|off`` (default: off) 1077 This enables caching mode for the VT-d emulated device. When 1078 caching-mode is enabled, each guest DMA buffer mapping will generate an 1079 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1080 a synchronous way. It is required for ``-device vfio-pci`` to work 1081 with the VT-d device, because host assigned devices requires to setup 1082 the DMA mapping on the host before guest DMA starts. 1083 1084 ``device-iotlb=on|off`` (default: off) 1085 This enables device-iotlb capability for the emulated VT-d device. So 1086 far virtio/vhost should be the only real user for this parameter, 1087 paired with ats=on configured for the device. 1088 1089 ``aw-bits=39|48`` (default: 39) 1090 This decides the address width of IOVA address space. The address 1091 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1092 4-level IOMMU page tables. 1093 1094 Please also refer to the wiki page for general scenarios of VT-d 1095 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1096 1097ERST 1098 1099DEF("name", HAS_ARG, QEMU_OPTION_name, 1100 "-name string1[,process=string2][,debug-threads=on|off]\n" 1101 " set the name of the guest\n" 1102 " string1 sets the window title and string2 the process name\n" 1103 " When debug-threads is enabled, individual threads are given a separate name\n" 1104 " NOTE: The thread names are for debugging and not a stable API.\n", 1105 QEMU_ARCH_ALL) 1106SRST 1107``-name name`` 1108 Sets the name of the guest. This name will be displayed in the SDL 1109 window caption. The name will also be used for the VNC server. Also 1110 optionally set the top visible process name in Linux. Naming of 1111 individual threads can also be enabled on Linux to aid debugging. 1112ERST 1113 1114DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1115 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1116 " specify machine UUID\n", QEMU_ARCH_ALL) 1117SRST 1118``-uuid uuid`` 1119 Set system UUID. 1120ERST 1121 1122DEFHEADING() 1123 1124DEFHEADING(Block device options:) 1125 1126SRST 1127The QEMU block device handling options have a long history and 1128have gone through several iterations as the feature set and complexity 1129of the block layer have grown. Many online guides to QEMU often 1130reference older and deprecated options, which can lead to confusion. 1131 1132The recommended modern way to describe disks is to use a combination of 1133``-device`` to specify the hardware device and ``-blockdev`` to 1134describe the backend. The device defines what the guest sees and the 1135backend describes how QEMU handles the data. 1136 1137ERST 1138 1139DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1140 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1141DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1142SRST 1143``-fda file`` 1144 \ 1145``-fdb file`` 1146 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1147 the System Emulation Users Guide). 1148ERST 1149 1150DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1151 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1152DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1153DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1154 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1155DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1156SRST 1157``-hda file`` 1158 \ 1159``-hdb file`` 1160 \ 1161``-hdc file`` 1162 \ 1163``-hdd file`` 1164 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1165 chapter in the System Emulation Users Guide). 1166ERST 1167 1168DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1169 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1170 QEMU_ARCH_ALL) 1171SRST 1172``-cdrom file`` 1173 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1174 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1175 as filename. 1176ERST 1177 1178DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1179 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1180 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1181 " [,read-only=on|off][,auto-read-only=on|off]\n" 1182 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1183 " [,driver specific parameters...]\n" 1184 " configure a block backend\n", QEMU_ARCH_ALL) 1185SRST 1186``-blockdev option[,option[,option[,...]]]`` 1187 Define a new block driver node. Some of the options apply to all 1188 block drivers, other options are only accepted for a specific block 1189 driver. See below for a list of generic options and options for the 1190 most common block drivers. 1191 1192 Options that expect a reference to another node (e.g. ``file``) can 1193 be given in two ways. Either you specify the node name of an already 1194 existing node (file=node-name), or you define a new node inline, 1195 adding options for the referenced node after a dot 1196 (file.filename=path,file.aio=native). 1197 1198 A block driver node created with ``-blockdev`` can be used for a 1199 guest device by specifying its node name for the ``drive`` property 1200 in a ``-device`` argument that defines a block device. 1201 1202 ``Valid options for any block driver node:`` 1203 ``driver`` 1204 Specifies the block driver to use for the given node. 1205 1206 ``node-name`` 1207 This defines the name of the block driver node by which it 1208 will be referenced later. The name must be unique, i.e. it 1209 must not match the name of a different block driver node, or 1210 (if you use ``-drive`` as well) the ID of a drive. 1211 1212 If no node name is specified, it is automatically generated. 1213 The generated node name is not intended to be predictable 1214 and changes between QEMU invocations. For the top level, an 1215 explicit node name must be specified. 1216 1217 ``read-only`` 1218 Open the node read-only. Guest write attempts will fail. 1219 1220 Note that some block drivers support only read-only access, 1221 either generally or in certain configurations. In this case, 1222 the default value ``read-only=off`` does not work and the 1223 option must be specified explicitly. 1224 1225 ``auto-read-only`` 1226 If ``auto-read-only=on`` is set, QEMU may fall back to 1227 read-only usage even when ``read-only=off`` is requested, or 1228 even switch between modes as needed, e.g. depending on 1229 whether the image file is writable or whether a writing user 1230 is attached to the node. 1231 1232 ``force-share`` 1233 Override the image locking system of QEMU by forcing the 1234 node to utilize weaker shared access for permissions where 1235 it would normally request exclusive access. When there is 1236 the potential for multiple instances to have the same file 1237 open (whether this invocation of QEMU is the first or the 1238 second instance), both instances must permit shared access 1239 for the second instance to succeed at opening the file. 1240 1241 Enabling ``force-share=on`` requires ``read-only=on``. 1242 1243 ``cache.direct`` 1244 The host page cache can be avoided with ``cache.direct=on``. 1245 This will attempt to do disk IO directly to the guest's 1246 memory. QEMU may still perform an internal copy of the data. 1247 1248 ``cache.no-flush`` 1249 In case you don't care about data integrity over host 1250 failures, you can use ``cache.no-flush=on``. This option 1251 tells QEMU that it never needs to write any data to the disk 1252 but can instead keep things in cache. If anything goes 1253 wrong, like your host losing power, the disk storage getting 1254 disconnected accidentally, etc. your image will most 1255 probably be rendered unusable. 1256 1257 ``discard=discard`` 1258 discard is one of "ignore" (or "off") or "unmap" (or "on") 1259 and controls whether ``discard`` (also known as ``trim`` or 1260 ``unmap``) requests are ignored or passed to the filesystem. 1261 Some machine types may not support discard requests. 1262 1263 ``detect-zeroes=detect-zeroes`` 1264 detect-zeroes is "off", "on" or "unmap" and enables the 1265 automatic conversion of plain zero writes by the OS to 1266 driver specific optimized zero write commands. You may even 1267 choose "unmap" if discard is set to "unmap" to allow a zero 1268 write to be converted to an ``unmap`` operation. 1269 1270 ``Driver-specific options for file`` 1271 This is the protocol-level block driver for accessing regular 1272 files. 1273 1274 ``filename`` 1275 The path to the image file in the local filesystem 1276 1277 ``aio`` 1278 Specifies the AIO backend (threads/native/io_uring, 1279 default: threads) 1280 1281 ``locking`` 1282 Specifies whether the image file is protected with Linux OFD 1283 / POSIX locks. The default is to use the Linux Open File 1284 Descriptor API if available, otherwise no lock is applied. 1285 (auto/on/off, default: auto) 1286 1287 Example: 1288 1289 :: 1290 1291 -blockdev driver=file,node-name=disk,filename=disk.img 1292 1293 ``Driver-specific options for raw`` 1294 This is the image format block driver for raw images. It is 1295 usually stacked on top of a protocol level block driver such as 1296 ``file``. 1297 1298 ``file`` 1299 Reference to or definition of the data source block driver 1300 node (e.g. a ``file`` driver node) 1301 1302 Example 1: 1303 1304 :: 1305 1306 -blockdev driver=file,node-name=disk_file,filename=disk.img 1307 -blockdev driver=raw,node-name=disk,file=disk_file 1308 1309 Example 2: 1310 1311 :: 1312 1313 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1314 1315 ``Driver-specific options for qcow2`` 1316 This is the image format block driver for qcow2 images. It is 1317 usually stacked on top of a protocol level block driver such as 1318 ``file``. 1319 1320 ``file`` 1321 Reference to or definition of the data source block driver 1322 node (e.g. a ``file`` driver node) 1323 1324 ``backing`` 1325 Reference to or definition of the backing file block device 1326 (default is taken from the image file). It is allowed to 1327 pass ``null`` here in order to disable the default backing 1328 file. 1329 1330 ``lazy-refcounts`` 1331 Whether to enable the lazy refcounts feature (on/off; 1332 default is taken from the image file) 1333 1334 ``cache-size`` 1335 The maximum total size of the L2 table and refcount block 1336 caches in bytes (default: the sum of l2-cache-size and 1337 refcount-cache-size) 1338 1339 ``l2-cache-size`` 1340 The maximum size of the L2 table cache in bytes (default: if 1341 cache-size is not specified - 32M on Linux platforms, and 8M 1342 on non-Linux platforms; otherwise, as large as possible 1343 within the cache-size, while permitting the requested or the 1344 minimal refcount cache size) 1345 1346 ``refcount-cache-size`` 1347 The maximum size of the refcount block cache in bytes 1348 (default: 4 times the cluster size; or if cache-size is 1349 specified, the part of it which is not used for the L2 1350 cache) 1351 1352 ``cache-clean-interval`` 1353 Clean unused entries in the L2 and refcount caches. The 1354 interval is in seconds. The default value is 600 on 1355 supporting platforms, and 0 on other platforms. Setting it 1356 to 0 disables this feature. 1357 1358 ``pass-discard-request`` 1359 Whether discard requests to the qcow2 device should be 1360 forwarded to the data source (on/off; default: on if 1361 discard=unmap is specified, off otherwise) 1362 1363 ``pass-discard-snapshot`` 1364 Whether discard requests for the data source should be 1365 issued when a snapshot operation (e.g. deleting a snapshot) 1366 frees clusters in the qcow2 file (on/off; default: on) 1367 1368 ``pass-discard-other`` 1369 Whether discard requests for the data source should be 1370 issued on other occasions where a cluster gets freed 1371 (on/off; default: off) 1372 1373 ``overlap-check`` 1374 Which overlap checks to perform for writes to the image 1375 (none/constant/cached/all; default: cached). For details or 1376 finer granularity control refer to the QAPI documentation of 1377 ``blockdev-add``. 1378 1379 Example 1: 1380 1381 :: 1382 1383 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1384 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1385 1386 Example 2: 1387 1388 :: 1389 1390 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1391 1392 ``Driver-specific options for other drivers`` 1393 Please refer to the QAPI documentation of the ``blockdev-add`` 1394 QMP command. 1395ERST 1396 1397DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1398 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1399 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1400 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1401 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1402 " [,aio=threads|native|io_uring]\n" 1403 " [,readonly=on|off][,copy-on-read=on|off]\n" 1404 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1405 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1406 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1407 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1408 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1409 " [[,iops_size=is]]\n" 1410 " [[,group=g]]\n" 1411 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1412SRST 1413``-drive option[,option[,option[,...]]]`` 1414 Define a new drive. This includes creating a block driver node (the 1415 backend) as well as a guest device, and is mostly a shortcut for 1416 defining the corresponding ``-blockdev`` and ``-device`` options. 1417 1418 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1419 In addition, it knows the following options: 1420 1421 ``file=file`` 1422 This option defines which disk image (see the :ref:`disk images` 1423 chapter in the System Emulation Users Guide) to use with this drive. 1424 If the filename contains comma, you must double it (for instance, 1425 "file=my,,file" to use file "my,file"). 1426 1427 Special files such as iSCSI devices can be specified using 1428 protocol specific URLs. See the section for "Device URL Syntax" 1429 for more information. 1430 1431 ``if=interface`` 1432 This option defines on which type on interface the drive is 1433 connected. Available types are: ide, scsi, sd, mtd, floppy, 1434 pflash, virtio, none. 1435 1436 ``bus=bus,unit=unit`` 1437 These options define where is connected the drive by defining 1438 the bus number and the unit id. 1439 1440 ``index=index`` 1441 This option defines where the drive is connected by using an 1442 index in the list of available connectors of a given interface 1443 type. 1444 1445 ``media=media`` 1446 This option defines the type of the media: disk or cdrom. 1447 1448 ``snapshot=snapshot`` 1449 snapshot is "on" or "off" and controls snapshot mode for the 1450 given drive (see ``-snapshot``). 1451 1452 ``cache=cache`` 1453 cache is "none", "writeback", "unsafe", "directsync" or 1454 "writethrough" and controls how the host cache is used to access 1455 block data. This is a shortcut that sets the ``cache.direct`` 1456 and ``cache.no-flush`` options (as in ``-blockdev``), and 1457 additionally ``cache.writeback``, which provides a default for 1458 the ``write-cache`` option of block guest devices (as in 1459 ``-device``). The modes correspond to the following settings: 1460 1461 ============= =============== ============ ============== 1462 \ cache.writeback cache.direct cache.no-flush 1463 ============= =============== ============ ============== 1464 writeback on off off 1465 none on on off 1466 writethrough off off off 1467 directsync off on off 1468 unsafe on off on 1469 ============= =============== ============ ============== 1470 1471 The default mode is ``cache=writeback``. 1472 1473 ``aio=aio`` 1474 aio is "threads", "native", or "io_uring" and selects between pthread 1475 based disk I/O, native Linux AIO, or Linux io_uring API. 1476 1477 ``format=format`` 1478 Specify which disk format will be used rather than detecting the 1479 format. Can be used to specify format=raw to avoid interpreting 1480 an untrusted format header. 1481 1482 ``werror=action,rerror=action`` 1483 Specify which action to take on write and read errors. Valid 1484 actions are: "ignore" (ignore the error and try to continue), 1485 "stop" (pause QEMU), "report" (report the error to the guest), 1486 "enospc" (pause QEMU only if the host disk is full; report the 1487 error to the guest otherwise). The default setting is 1488 ``werror=enospc`` and ``rerror=report``. 1489 1490 ``copy-on-read=copy-on-read`` 1491 copy-on-read is "on" or "off" and enables whether to copy read 1492 backing file sectors into the image file. 1493 1494 ``bps=b,bps_rd=r,bps_wr=w`` 1495 Specify bandwidth throttling limits in bytes per second, either 1496 for all request types or for reads or writes only. Small values 1497 can lead to timeouts or hangs inside the guest. A safe minimum 1498 for disks is 2 MB/s. 1499 1500 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1501 Specify bursts in bytes per second, either for all request types 1502 or for reads or writes only. Bursts allow the guest I/O to spike 1503 above the limit temporarily. 1504 1505 ``iops=i,iops_rd=r,iops_wr=w`` 1506 Specify request rate limits in requests per second, either for 1507 all request types or for reads or writes only. 1508 1509 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1510 Specify bursts in requests per second, either for all request 1511 types or for reads or writes only. Bursts allow the guest I/O to 1512 spike above the limit temporarily. 1513 1514 ``iops_size=is`` 1515 Let every is bytes of a request count as a new request for iops 1516 throttling purposes. Use this option to prevent guests from 1517 circumventing iops limits by sending fewer but larger requests. 1518 1519 ``group=g`` 1520 Join a throttling quota group with given name g. All drives that 1521 are members of the same group are accounted for together. Use 1522 this option to prevent guests from circumventing throttling 1523 limits by using many small disks instead of a single larger 1524 disk. 1525 1526 By default, the ``cache.writeback=on`` mode is used. It will report 1527 data writes as completed as soon as the data is present in the host 1528 page cache. This is safe as long as your guest OS makes sure to 1529 correctly flush disk caches where needed. If your guest OS does not 1530 handle volatile disk write caches correctly and your host crashes or 1531 loses power, then the guest may experience data corruption. 1532 1533 For such guests, you should consider using ``cache.writeback=off``. 1534 This means that the host page cache will be used to read and write 1535 data, but write notification will be sent to the guest only after 1536 QEMU has made sure to flush each write to the disk. Be aware that 1537 this has a major impact on performance. 1538 1539 When using the ``-snapshot`` option, unsafe caching is always used. 1540 1541 Copy-on-read avoids accessing the same backing file sectors 1542 repeatedly and is useful when the backing file is over a slow 1543 network. By default copy-on-read is off. 1544 1545 Instead of ``-cdrom`` you can use: 1546 1547 .. parsed-literal:: 1548 1549 |qemu_system| -drive file=file,index=2,media=cdrom 1550 1551 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1552 1553 .. parsed-literal:: 1554 1555 |qemu_system| -drive file=file,index=0,media=disk 1556 |qemu_system| -drive file=file,index=1,media=disk 1557 |qemu_system| -drive file=file,index=2,media=disk 1558 |qemu_system| -drive file=file,index=3,media=disk 1559 1560 You can open an image using pre-opened file descriptors from an fd 1561 set: 1562 1563 .. parsed-literal:: 1564 1565 |qemu_system| \\ 1566 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1567 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1568 -drive file=/dev/fdset/2,index=0,media=disk 1569 1570 You can connect a CDROM to the slave of ide0: 1571 1572 .. parsed-literal:: 1573 1574 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1575 1576 If you don't specify the "file=" argument, you define an empty 1577 drive: 1578 1579 .. parsed-literal:: 1580 1581 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1582 1583 Instead of ``-fda``, ``-fdb``, you can use: 1584 1585 .. parsed-literal:: 1586 1587 |qemu_system_x86| -drive file=file,index=0,if=floppy 1588 |qemu_system_x86| -drive file=file,index=1,if=floppy 1589 1590 By default, interface is "ide" and index is automatically 1591 incremented: 1592 1593 .. parsed-literal:: 1594 1595 |qemu_system_x86| -drive file=a -drive file=b" 1596 1597 is interpreted like: 1598 1599 .. parsed-literal:: 1600 1601 |qemu_system_x86| -hda a -hdb b 1602ERST 1603 1604DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1605 "-mtdblock file use 'file' as on-board Flash memory image\n", 1606 QEMU_ARCH_ALL) 1607SRST 1608``-mtdblock file`` 1609 Use file as on-board Flash memory image. 1610ERST 1611 1612DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1613 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1614SRST 1615``-sd file`` 1616 Use file as SecureDigital card image. 1617ERST 1618 1619DEF("snapshot", 0, QEMU_OPTION_snapshot, 1620 "-snapshot write to temporary files instead of disk image files\n", 1621 QEMU_ARCH_ALL) 1622SRST 1623``-snapshot`` 1624 Write to temporary files instead of disk image files. In this case, 1625 the raw disk image you use is not written back. You can however 1626 force the write back by pressing C-a s (see the :ref:`disk images` 1627 chapter in the System Emulation Users Guide). 1628ERST 1629 1630DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1631 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1632 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1633 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1634 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1635 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1636 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1637 " [[,throttling.iops-size=is]]\n" 1638 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1639 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1640 "-fsdev synth,id=id\n", 1641 QEMU_ARCH_ALL) 1642 1643SRST 1644``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1645 \ 1646``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1647 \ 1648``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1649 \ 1650``-fsdev synth,id=id[,readonly=on]`` 1651 Define a new file system device. Valid options are: 1652 1653 ``local`` 1654 Accesses to the filesystem are done by QEMU. 1655 1656 ``proxy`` 1657 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1658 1659 ``synth`` 1660 Synthetic filesystem, only used by QTests. 1661 1662 ``id=id`` 1663 Specifies identifier for this device. 1664 1665 ``path=path`` 1666 Specifies the export path for the file system device. Files 1667 under this path will be available to the 9p client on the guest. 1668 1669 ``security_model=security_model`` 1670 Specifies the security model to be used for this export path. 1671 Supported security models are "passthrough", "mapped-xattr", 1672 "mapped-file" and "none". In "passthrough" security model, files 1673 are stored using the same credentials as they are created on the 1674 guest. This requires QEMU to run as root. In "mapped-xattr" 1675 security model, some of the file attributes like uid, gid, mode 1676 bits and link target are stored as file attributes. For 1677 "mapped-file" these attributes are stored in the hidden 1678 .virtfs\_metadata directory. Directories exported by this 1679 security model cannot interact with other unix tools. "none" 1680 security model is same as passthrough except the sever won't 1681 report failures if it fails to set file attributes like 1682 ownership. Security model is mandatory only for local fsdriver. 1683 Other fsdrivers (like proxy) don't take security model as a 1684 parameter. 1685 1686 ``writeout=writeout`` 1687 This is an optional argument. The only supported value is 1688 "immediate". This means that host page cache will be used to 1689 read and write data but write notification will be sent to the 1690 guest only when the data has been reported as written by the 1691 storage subsystem. 1692 1693 ``readonly=on`` 1694 Enables exporting 9p share as a readonly mount for guests. By 1695 default read-write access is given. 1696 1697 ``socket=socket`` 1698 Enables proxy filesystem driver to use passed socket file for 1699 communicating with virtfs-proxy-helper(1). 1700 1701 ``sock_fd=sock_fd`` 1702 Enables proxy filesystem driver to use passed socket descriptor 1703 for communicating with virtfs-proxy-helper(1). Usually a helper 1704 like libvirt will create socketpair and pass one of the fds as 1705 sock\_fd. 1706 1707 ``fmode=fmode`` 1708 Specifies the default mode for newly created files on the host. 1709 Works only with security models "mapped-xattr" and 1710 "mapped-file". 1711 1712 ``dmode=dmode`` 1713 Specifies the default mode for newly created directories on the 1714 host. Works only with security models "mapped-xattr" and 1715 "mapped-file". 1716 1717 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1718 Specify bandwidth throttling limits in bytes per second, either 1719 for all request types or for reads or writes only. 1720 1721 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1722 Specify bursts in bytes per second, either for all request types 1723 or for reads or writes only. Bursts allow the guest I/O to spike 1724 above the limit temporarily. 1725 1726 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1727 Specify request rate limits in requests per second, either for 1728 all request types or for reads or writes only. 1729 1730 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1731 Specify bursts in requests per second, either for all request 1732 types or for reads or writes only. Bursts allow the guest I/O to 1733 spike above the limit temporarily. 1734 1735 ``throttling.iops-size=is`` 1736 Let every is bytes of a request count as a new request for iops 1737 throttling purposes. 1738 1739 -fsdev option is used along with -device driver "virtio-9p-...". 1740 1741``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1742 Options for virtio-9p-... driver are: 1743 1744 ``type`` 1745 Specifies the variant to be used. Supported values are "pci", 1746 "ccw" or "device", depending on the machine type. 1747 1748 ``fsdev=id`` 1749 Specifies the id value specified along with -fsdev option. 1750 1751 ``mount_tag=mount_tag`` 1752 Specifies the tag name to be used by the guest to mount this 1753 export point. 1754ERST 1755 1756DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1757 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1758 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1759 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1760 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1761 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1762 QEMU_ARCH_ALL) 1763 1764SRST 1765``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1766 \ 1767``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1768 \ 1769``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1770 \ 1771``-virtfs synth,mount_tag=mount_tag`` 1772 Define a new virtual filesystem device and expose it to the guest using 1773 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1774 directory on host is made directly accessible by guest as a pass-through 1775 file system by using the 9P network protocol for communication between 1776 host and guests, if desired even accessible, shared by several guests 1777 simultaniously. 1778 1779 Note that ``-virtfs`` is actually just a convenience shortcut for its 1780 generalized form ``-fsdev -device virtio-9p-pci``. 1781 1782 The general form of pass-through file system options are: 1783 1784 ``local`` 1785 Accesses to the filesystem are done by QEMU. 1786 1787 ``proxy`` 1788 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1789 1790 ``synth`` 1791 Synthetic filesystem, only used by QTests. 1792 1793 ``id=id`` 1794 Specifies identifier for the filesystem device 1795 1796 ``path=path`` 1797 Specifies the export path for the file system device. Files 1798 under this path will be available to the 9p client on the guest. 1799 1800 ``security_model=security_model`` 1801 Specifies the security model to be used for this export path. 1802 Supported security models are "passthrough", "mapped-xattr", 1803 "mapped-file" and "none". In "passthrough" security model, files 1804 are stored using the same credentials as they are created on the 1805 guest. This requires QEMU to run as root. In "mapped-xattr" 1806 security model, some of the file attributes like uid, gid, mode 1807 bits and link target are stored as file attributes. For 1808 "mapped-file" these attributes are stored in the hidden 1809 .virtfs\_metadata directory. Directories exported by this 1810 security model cannot interact with other unix tools. "none" 1811 security model is same as passthrough except the sever won't 1812 report failures if it fails to set file attributes like 1813 ownership. Security model is mandatory only for local fsdriver. 1814 Other fsdrivers (like proxy) don't take security model as a 1815 parameter. 1816 1817 ``writeout=writeout`` 1818 This is an optional argument. The only supported value is 1819 "immediate". This means that host page cache will be used to 1820 read and write data but write notification will be sent to the 1821 guest only when the data has been reported as written by the 1822 storage subsystem. 1823 1824 ``readonly=on`` 1825 Enables exporting 9p share as a readonly mount for guests. By 1826 default read-write access is given. 1827 1828 ``socket=socket`` 1829 Enables proxy filesystem driver to use passed socket file for 1830 communicating with virtfs-proxy-helper(1). Usually a helper like 1831 libvirt will create socketpair and pass one of the fds as 1832 sock\_fd. 1833 1834 ``sock_fd`` 1835 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1836 socket descriptor for interfacing with virtfs-proxy-helper(1). 1837 1838 ``fmode=fmode`` 1839 Specifies the default mode for newly created files on the host. 1840 Works only with security models "mapped-xattr" and 1841 "mapped-file". 1842 1843 ``dmode=dmode`` 1844 Specifies the default mode for newly created directories on the 1845 host. Works only with security models "mapped-xattr" and 1846 "mapped-file". 1847 1848 ``mount_tag=mount_tag`` 1849 Specifies the tag name to be used by the guest to mount this 1850 export point. 1851 1852 ``multidevs=multidevs`` 1853 Specifies how to deal with multiple devices being shared with a 1854 9p export. Supported behaviours are either "remap", "forbid" or 1855 "warn". The latter is the default behaviour on which virtfs 9p 1856 expects only one device to be shared with the same export, and 1857 if more than one device is shared and accessed via the same 9p 1858 export then only a warning message is logged (once) by qemu on 1859 host side. In order to avoid file ID collisions on guest you 1860 should either create a separate virtfs export for each device to 1861 be shared with guests (recommended way) or you might use "remap" 1862 instead which allows you to share multiple devices with only one 1863 export instead, which is achieved by remapping the original 1864 inode numbers from host to guest in a way that would prevent 1865 such collisions. Remapping inodes in such use cases is required 1866 because the original device IDs from host are never passed and 1867 exposed on guest. Instead all files of an export shared with 1868 virtfs always share the same device id on guest. So two files 1869 with identical inode numbers but from actually different devices 1870 on host would otherwise cause a file ID collision and hence 1871 potential misbehaviours on guest. "forbid" on the other hand 1872 assumes like "warn" that only one device is shared by the same 1873 export, however it will not only log a warning message but also 1874 deny access to additional devices on guest. Note though that 1875 "forbid" does currently not block all possible file access 1876 operations (e.g. readdir() would still return entries from other 1877 devices). 1878ERST 1879 1880DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1881 "-iscsi [user=user][,password=password]\n" 1882 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1883 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1884 " [,timeout=timeout]\n" 1885 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1886 1887SRST 1888``-iscsi`` 1889 Configure iSCSI session parameters. 1890ERST 1891 1892DEFHEADING() 1893 1894DEFHEADING(USB convenience options:) 1895 1896DEF("usb", 0, QEMU_OPTION_usb, 1897 "-usb enable on-board USB host controller (if not enabled by default)\n", 1898 QEMU_ARCH_ALL) 1899SRST 1900``-usb`` 1901 Enable USB emulation on machine types with an on-board USB host 1902 controller (if not enabled by default). Note that on-board USB host 1903 controllers may not support USB 3.0. In this case 1904 ``-device qemu-xhci`` can be used instead on machines with PCI. 1905ERST 1906 1907DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1908 "-usbdevice name add the host or guest USB device 'name'\n", 1909 QEMU_ARCH_ALL) 1910SRST 1911``-usbdevice devname`` 1912 Add the USB device devname, and enable an on-board USB controller 1913 if possible and necessary (just like it can be done via 1914 ``-machine usb=on``). Note that this option is mainly intended for 1915 the user's convenience only. More fine-grained control can be 1916 achieved by selecting a USB host controller (if necessary) and the 1917 desired USB device via the ``-device`` option instead. For example, 1918 instead of using ``-usbdevice mouse`` it is possible to use 1919 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1920 to a USB 3.0 controller instead (at least on machines that support 1921 PCI and do not have an USB controller enabled by default yet). 1922 For more details, see the chapter about 1923 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1924 Possible devices for devname are: 1925 1926 ``braille`` 1927 Braille device. This will use BrlAPI to display the braille 1928 output on a real or fake device (i.e. it also creates a 1929 corresponding ``braille`` chardev automatically beside the 1930 ``usb-braille`` USB device). 1931 1932 ``keyboard`` 1933 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1934 1935 ``mouse`` 1936 Virtual Mouse. This will override the PS/2 mouse emulation when 1937 activated. 1938 1939 ``tablet`` 1940 Pointer device that uses absolute coordinates (like a 1941 touchscreen). This means QEMU is able to report the mouse 1942 position without having to grab the mouse. Also overrides the 1943 PS/2 mouse emulation when activated. 1944 1945 ``wacom-tablet`` 1946 Wacom PenPartner USB tablet. 1947 1948 1949ERST 1950 1951DEFHEADING() 1952 1953DEFHEADING(Display options:) 1954 1955DEF("display", HAS_ARG, QEMU_OPTION_display, 1956#if defined(CONFIG_SPICE) 1957 "-display spice-app[,gl=on|off]\n" 1958#endif 1959#if defined(CONFIG_SDL) 1960 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 1961 " [,window-close=on|off]\n" 1962#endif 1963#if defined(CONFIG_GTK) 1964 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1965 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 1966#endif 1967#if defined(CONFIG_VNC) 1968 "-display vnc=<display>[,<optargs>]\n" 1969#endif 1970#if defined(CONFIG_CURSES) 1971 "-display curses[,charset=<encoding>]\n" 1972#endif 1973#if defined(CONFIG_COCOA) 1974 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 1975#endif 1976#if defined(CONFIG_OPENGL) 1977 "-display egl-headless[,rendernode=<file>]\n" 1978#endif 1979#if defined(CONFIG_DBUS_DISPLAY) 1980 "-display dbus[,addr=<dbusaddr>]\n" 1981 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1982#endif 1983#if defined(CONFIG_COCOA) 1984 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 1985#endif 1986 "-display none\n" 1987 " select display backend type\n" 1988 " The default display is equivalent to\n " 1989#if defined(CONFIG_GTK) 1990 "\"-display gtk\"\n" 1991#elif defined(CONFIG_SDL) 1992 "\"-display sdl\"\n" 1993#elif defined(CONFIG_COCOA) 1994 "\"-display cocoa\"\n" 1995#elif defined(CONFIG_VNC) 1996 "\"-vnc localhost:0,to=99,id=default\"\n" 1997#else 1998 "\"-display none\"\n" 1999#endif 2000 , QEMU_ARCH_ALL) 2001SRST 2002``-display type`` 2003 Select type of display to use. Use ``-display help`` to list the available 2004 display types. Valid values for type are 2005 2006 ``spice-app[,gl=on|off]`` 2007 Start QEMU as a Spice server and launch the default Spice client 2008 application. The Spice server will redirect the serial consoles 2009 and QEMU monitors. (Since 4.0) 2010 2011 ``dbus`` 2012 Export the display over D-Bus interfaces. (Since 7.0) 2013 2014 The connection is registered with the "org.qemu" name (and queued when 2015 already owned). 2016 2017 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2018 2019 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2020 2021 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2022 will share framebuffers with DMABUF file descriptors). 2023 2024 ``sdl`` 2025 Display video output via SDL (usually in a separate graphics 2026 window; see the SDL documentation for other possibilities). 2027 Valid parameters are: 2028 2029 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2030 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2031 either ``lshift-lctrl-lalt`` or ``rctrl``. 2032 2033 ``gl=on|off|core|es`` : Use OpenGL for displaying 2034 2035 ``show-cursor=on|off`` : Force showing the mouse cursor 2036 2037 ``window-close=on|off`` : Allow to quit qemu with window close button 2038 2039 ``gtk`` 2040 Display video output in a GTK window. This interface provides 2041 drop-down menus and other UI elements to configure and control 2042 the VM during runtime. Valid parameters are: 2043 2044 ``full-screen=on|off`` : Start in fullscreen mode 2045 2046 ``gl=on|off`` : Use OpenGL for displaying 2047 2048 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2049 2050 ``show-tabs=on|off`` : Display the tab bar for switching between the 2051 various graphical interfaces (e.g. VGA and 2052 virtual console character devices) by default. 2053 2054 ``show-cursor=on|off`` : Force showing the mouse cursor 2055 2056 ``window-close=on|off`` : Allow to quit qemu with window close button 2057 2058 ``curses[,charset=<encoding>]`` 2059 Display video output via curses. For graphics device models 2060 which support a text mode, QEMU can display this output using a 2061 curses/ncurses interface. Nothing is displayed when the graphics 2062 device is in graphical mode or if the graphics device does not 2063 support a text mode. Generally only the VGA device models 2064 support text mode. The font charset used by the guest can be 2065 specified with the ``charset`` option, for example 2066 ``charset=CP850`` for IBM CP850 encoding. The default is 2067 ``CP437``. 2068 2069 ``cocoa`` 2070 Display video output in a Cocoa window. Mac only. This interface 2071 provides drop-down menus and other UI elements to configure and 2072 control the VM during runtime. Valid parameters are: 2073 2074 ``show-cursor=on|off`` : Force showing the mouse cursor 2075 2076 ``left-command-key=on|off`` : Disable forwarding left command key to host 2077 2078 ``egl-headless[,rendernode=<file>]`` 2079 Offload all OpenGL operations to a local DRI device. For any 2080 graphical display, this display needs to be paired with either 2081 VNC or SPICE displays. 2082 2083 ``vnc=<display>`` 2084 Start a VNC server on display <display> 2085 2086 ``none`` 2087 Do not display video output. The guest will still see an 2088 emulated graphics card, but its output will not be displayed to 2089 the QEMU user. This option differs from the -nographic option in 2090 that it only affects what is done with video output; -nographic 2091 also changes the destination of the serial and parallel port 2092 data. 2093ERST 2094 2095DEF("nographic", 0, QEMU_OPTION_nographic, 2096 "-nographic disable graphical output and redirect serial I/Os to console\n", 2097 QEMU_ARCH_ALL) 2098SRST 2099``-nographic`` 2100 Normally, if QEMU is compiled with graphical window support, it 2101 displays output such as guest graphics, guest console, and the QEMU 2102 monitor in a window. With this option, you can totally disable 2103 graphical output so that QEMU is a simple command line application. 2104 The emulated serial port is redirected on the console and muxed with 2105 the monitor (unless redirected elsewhere explicitly). Therefore, you 2106 can still use QEMU to debug a Linux kernel with a serial console. 2107 Use C-a h for help on switching between the console and monitor. 2108ERST 2109 2110#ifdef CONFIG_SPICE 2111DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2112 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2113 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2114 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2115 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2116 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2117 " [,tls-ciphers=<list>]\n" 2118 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2119 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2120 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2121 " [,password=<string>][,password-secret=<secret-id>]\n" 2122 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2123 " [,jpeg-wan-compression=[auto|never|always]]\n" 2124 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2125 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2126 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2127 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2128 " [,gl=[on|off]][,rendernode=<file>]\n" 2129 " enable spice\n" 2130 " at least one of {port, tls-port} is mandatory\n", 2131 QEMU_ARCH_ALL) 2132#endif 2133SRST 2134``-spice option[,option[,...]]`` 2135 Enable the spice remote desktop protocol. Valid options are 2136 2137 ``port=<nr>`` 2138 Set the TCP port spice is listening on for plaintext channels. 2139 2140 ``addr=<addr>`` 2141 Set the IP address spice is listening on. Default is any 2142 address. 2143 2144 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2145 Force using the specified IP version. 2146 2147 ``password=<string>`` 2148 Set the password you need to authenticate. 2149 2150 This option is deprecated and insecure because it leaves the 2151 password visible in the process listing. Use ``password-secret`` 2152 instead. 2153 2154 ``password-secret=<secret-id>`` 2155 Set the ID of the ``secret`` object containing the password 2156 you need to authenticate. 2157 2158 ``sasl=on|off`` 2159 Require that the client use SASL to authenticate with the spice. 2160 The exact choice of authentication method used is controlled 2161 from the system / user's SASL configuration file for the 'qemu' 2162 service. This is typically found in /etc/sasl2/qemu.conf. If 2163 running QEMU as an unprivileged user, an environment variable 2164 SASL\_CONF\_PATH can be used to make it search alternate 2165 locations for the service config. While some SASL auth methods 2166 can also provide data encryption (eg GSSAPI), it is recommended 2167 that SASL always be combined with the 'tls' and 'x509' settings 2168 to enable use of SSL and server certificates. This ensures a 2169 data encryption preventing compromise of authentication 2170 credentials. 2171 2172 ``disable-ticketing=on|off`` 2173 Allow client connects without authentication. 2174 2175 ``disable-copy-paste=on|off`` 2176 Disable copy paste between the client and the guest. 2177 2178 ``disable-agent-file-xfer=on|off`` 2179 Disable spice-vdagent based file-xfer between the client and the 2180 guest. 2181 2182 ``tls-port=<nr>`` 2183 Set the TCP port spice is listening on for encrypted channels. 2184 2185 ``x509-dir=<dir>`` 2186 Set the x509 file directory. Expects same filenames as -vnc 2187 $display,x509=$dir 2188 2189 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2190 The x509 file names can also be configured individually. 2191 2192 ``tls-ciphers=<list>`` 2193 Specify which ciphers to use. 2194 2195 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2196 Force specific channel to be used with or without TLS 2197 encryption. The options can be specified multiple times to 2198 configure multiple channels. The special name "default" can be 2199 used to set the default mode. For channels which are not 2200 explicitly forced into one mode the spice client is allowed to 2201 pick tls/plaintext as he pleases. 2202 2203 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2204 Configure image compression (lossless). Default is auto\_glz. 2205 2206 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2207 Configure wan image compression (lossy for slow links). Default 2208 is auto. 2209 2210 ``streaming-video=[off|all|filter]`` 2211 Configure video stream detection. Default is off. 2212 2213 ``agent-mouse=[on|off]`` 2214 Enable/disable passing mouse events via vdagent. Default is on. 2215 2216 ``playback-compression=[on|off]`` 2217 Enable/disable audio stream compression (using celt 0.5.1). 2218 Default is on. 2219 2220 ``seamless-migration=[on|off]`` 2221 Enable/disable spice seamless migration. Default is off. 2222 2223 ``gl=[on|off]`` 2224 Enable/disable OpenGL context. Default is off. 2225 2226 ``rendernode=<file>`` 2227 DRM render node for OpenGL rendering. If not specified, it will 2228 pick the first available. (Since 2.9) 2229ERST 2230 2231DEF("portrait", 0, QEMU_OPTION_portrait, 2232 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2233 QEMU_ARCH_ALL) 2234SRST 2235``-portrait`` 2236 Rotate graphical output 90 deg left (only PXA LCD). 2237ERST 2238 2239DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2240 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2241 QEMU_ARCH_ALL) 2242SRST 2243``-rotate deg`` 2244 Rotate graphical output some deg left (only PXA LCD). 2245ERST 2246 2247DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2248 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2249 " select video card type\n", QEMU_ARCH_ALL) 2250SRST 2251``-vga type`` 2252 Select type of VGA card to emulate. Valid values for type are 2253 2254 ``cirrus`` 2255 Cirrus Logic GD5446 Video card. All Windows versions starting 2256 from Windows 95 should recognize and use this graphic card. For 2257 optimal performances, use 16 bit color depth in the guest and 2258 the host OS. (This card was the default before QEMU 2.2) 2259 2260 ``std`` 2261 Standard VGA card with Bochs VBE extensions. If your guest OS 2262 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2263 you want to use high resolution modes (>= 1280x1024x16) then you 2264 should use this option. (This card is the default since QEMU 2265 2.2) 2266 2267 ``vmware`` 2268 VMWare SVGA-II compatible adapter. Use it if you have 2269 sufficiently recent XFree86/XOrg server or Windows guest with a 2270 driver for this card. 2271 2272 ``qxl`` 2273 QXL paravirtual graphic card. It is VGA compatible (including 2274 VESA 2.0 VBE support). Works best with qxl guest drivers 2275 installed though. Recommended choice when using the spice 2276 protocol. 2277 2278 ``tcx`` 2279 (sun4m only) Sun TCX framebuffer. This is the default 2280 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2281 colour depths at a fixed resolution of 1024x768. 2282 2283 ``cg3`` 2284 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2285 framebuffer for sun4m machines available in both 1024x768 2286 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2287 wishing to run older Solaris versions. 2288 2289 ``virtio`` 2290 Virtio VGA card. 2291 2292 ``none`` 2293 Disable VGA card. 2294ERST 2295 2296DEF("full-screen", 0, QEMU_OPTION_full_screen, 2297 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2298SRST 2299``-full-screen`` 2300 Start in full screen. 2301ERST 2302 2303DEF("g", HAS_ARG, QEMU_OPTION_g , 2304 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2305 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2306SRST 2307``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2308 Set the initial graphical resolution and depth (PPC, SPARC only). 2309 2310 For PPC the default is 800x600x32. 2311 2312 For SPARC with the TCX graphics device, the default is 1024x768x8 2313 with the option of 1024x768x24. For cgthree, the default is 2314 1024x768x8 with the option of 1152x900x8 for people who wish to use 2315 OBP. 2316ERST 2317 2318DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2319 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2320SRST 2321``-vnc display[,option[,option[,...]]]`` 2322 Normally, if QEMU is compiled with graphical window support, it 2323 displays output such as guest graphics, guest console, and the QEMU 2324 monitor in a window. With this option, you can have QEMU listen on 2325 VNC display display and redirect the VGA display over the VNC 2326 session. It is very useful to enable the usb tablet device when 2327 using this option (option ``-device usb-tablet``). When using the 2328 VNC display, you must use the ``-k`` parameter to set the keyboard 2329 layout if you are not using en-us. Valid syntax for the display is 2330 2331 ``to=L`` 2332 With this option, QEMU will try next available VNC displays, 2333 until the number L, if the origianlly defined "-vnc display" is 2334 not available, e.g. port 5900+display is already used by another 2335 application. By default, to=0. 2336 2337 ``host:d`` 2338 TCP connections will only be allowed from host on display d. By 2339 convention the TCP port is 5900+d. Optionally, host can be 2340 omitted in which case the server will accept connections from 2341 any host. 2342 2343 ``unix:path`` 2344 Connections will be allowed over UNIX domain sockets where path 2345 is the location of a unix socket to listen for connections on. 2346 2347 ``none`` 2348 VNC is initialized but not started. The monitor ``change`` 2349 command can be used to later start the VNC server. 2350 2351 Following the display value there may be one or more option flags 2352 separated by commas. Valid options are 2353 2354 ``reverse=on|off`` 2355 Connect to a listening VNC client via a "reverse" connection. 2356 The client is specified by the display. For reverse network 2357 connections (host:d,``reverse``), the d argument is a TCP port 2358 number, not a display number. 2359 2360 ``websocket=on|off`` 2361 Opens an additional TCP listening port dedicated to VNC 2362 Websocket connections. If a bare websocket option is given, the 2363 Websocket port is 5700+display. An alternative port can be 2364 specified with the syntax ``websocket``\ =port. 2365 2366 If host is specified connections will only be allowed from this 2367 host. It is possible to control the websocket listen address 2368 independently, using the syntax ``websocket``\ =host:port. 2369 2370 If no TLS credentials are provided, the websocket connection 2371 runs in unencrypted mode. If TLS credentials are provided, the 2372 websocket connection requires encrypted client connections. 2373 2374 ``password=on|off`` 2375 Require that password based authentication is used for client 2376 connections. 2377 2378 The password must be set separately using the ``set_password`` 2379 command in the :ref:`QEMU monitor`. The 2380 syntax to change your password is: 2381 ``set_password <protocol> <password>`` where <protocol> could be 2382 either "vnc" or "spice". 2383 2384 If you would like to change <protocol> password expiration, you 2385 should use ``expire_password <protocol> <expiration-time>`` 2386 where expiration time could be one of the following options: 2387 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2388 make password expire in 60 seconds, or 1335196800 to make 2389 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2390 this date and time). 2391 2392 You can also use keywords "now" or "never" for the expiration 2393 time to allow <protocol> password to expire immediately or never 2394 expire. 2395 2396 ``password-secret=<secret-id>`` 2397 Require that password based authentication is used for client 2398 connections, using the password provided by the ``secret`` 2399 object identified by ``secret-id``. 2400 2401 ``tls-creds=ID`` 2402 Provides the ID of a set of TLS credentials to use to secure the 2403 VNC server. They will apply to both the normal VNC server socket 2404 and the websocket socket (if enabled). Setting TLS credentials 2405 will cause the VNC server socket to enable the VeNCrypt auth 2406 mechanism. The credentials should have been previously created 2407 using the ``-object tls-creds`` argument. 2408 2409 ``tls-authz=ID`` 2410 Provides the ID of the QAuthZ authorization object against which 2411 the client's x509 distinguished name will validated. This object 2412 is only resolved at time of use, so can be deleted and recreated 2413 on the fly while the VNC server is active. If missing, it will 2414 default to denying access. 2415 2416 ``sasl=on|off`` 2417 Require that the client use SASL to authenticate with the VNC 2418 server. The exact choice of authentication method used is 2419 controlled from the system / user's SASL configuration file for 2420 the 'qemu' service. This is typically found in 2421 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2422 an environment variable SASL\_CONF\_PATH can be used to make it 2423 search alternate locations for the service config. While some 2424 SASL auth methods can also provide data encryption (eg GSSAPI), 2425 it is recommended that SASL always be combined with the 'tls' 2426 and 'x509' settings to enable use of SSL and server 2427 certificates. This ensures a data encryption preventing 2428 compromise of authentication credentials. See the 2429 :ref:`VNC security` section in the System Emulation Users Guide 2430 for details on using SASL authentication. 2431 2432 ``sasl-authz=ID`` 2433 Provides the ID of the QAuthZ authorization object against which 2434 the client's SASL username will validated. This object is only 2435 resolved at time of use, so can be deleted and recreated on the 2436 fly while the VNC server is active. If missing, it will default 2437 to denying access. 2438 2439 ``acl=on|off`` 2440 Legacy method for enabling authorization of clients against the 2441 x509 distinguished name and SASL username. It results in the 2442 creation of two ``authz-list`` objects with IDs of 2443 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2444 objects must be configured with the HMP ACL commands. 2445 2446 This option is deprecated and should no longer be used. The new 2447 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2448 2449 ``lossy=on|off`` 2450 Enable lossy compression methods (gradient, JPEG, ...). If this 2451 option is set, VNC client may receive lossy framebuffer updates 2452 depending on its encoding settings. Enabling this option can 2453 save a lot of bandwidth at the expense of quality. 2454 2455 ``non-adaptive=on|off`` 2456 Disable adaptive encodings. Adaptive encodings are enabled by 2457 default. An adaptive encoding will try to detect frequently 2458 updated screen regions, and send updates in these regions using 2459 a lossy encoding (like JPEG). This can be really helpful to save 2460 bandwidth when playing videos. Disabling adaptive encodings 2461 restores the original static behavior of encodings like Tight. 2462 2463 ``share=[allow-exclusive|force-shared|ignore]`` 2464 Set display sharing policy. 'allow-exclusive' allows clients to 2465 ask for exclusive access. As suggested by the rfb spec this is 2466 implemented by dropping other connections. Connecting multiple 2467 clients in parallel requires all clients asking for a shared 2468 session (vncviewer: -shared switch). This is the default. 2469 'force-shared' disables exclusive client access. Useful for 2470 shared desktop sessions, where you don't want someone forgetting 2471 specify -shared disconnect everybody else. 'ignore' completely 2472 ignores the shared flag and allows everybody connect 2473 unconditionally. Doesn't conform to the rfb spec but is 2474 traditional QEMU behavior. 2475 2476 ``key-delay-ms`` 2477 Set keyboard delay, for key down and key up events, in 2478 milliseconds. Default is 10. Keyboards are low-bandwidth 2479 devices, so this slowdown can help the device and guest to keep 2480 up and not lose events in case events are arriving in bulk. 2481 Possible causes for the latter are flaky network connections, or 2482 scripts for automated testing. 2483 2484 ``audiodev=audiodev`` 2485 Use the specified audiodev when the VNC client requests audio 2486 transmission. When not using an -audiodev argument, this option 2487 must be omitted, otherwise is must be present and specify a 2488 valid audiodev. 2489 2490 ``power-control=on|off`` 2491 Permit the remote client to issue shutdown, reboot or reset power 2492 control requests. 2493ERST 2494 2495ARCHHEADING(, QEMU_ARCH_I386) 2496 2497ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2498 2499DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2500 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2501 QEMU_ARCH_I386) 2502SRST 2503``-win2k-hack`` 2504 Use it when installing Windows 2000 to avoid a disk full bug. After 2505 Windows 2000 is installed, you no longer need this option (this 2506 option slows down the IDE transfers). 2507ERST 2508 2509DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2510 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2511 QEMU_ARCH_I386) 2512SRST 2513``-no-fd-bootchk`` 2514 Disable boot signature checking for floppy disks in BIOS. May be 2515 needed to boot from old floppy disks. 2516ERST 2517 2518DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2519 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2520SRST 2521``-no-acpi`` 2522 Disable ACPI (Advanced Configuration and Power Interface) support. 2523 Use it if your guest OS complains about ACPI problems (PC target 2524 machine only). 2525ERST 2526 2527DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2528 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2529SRST 2530``-no-hpet`` 2531 Disable HPET support. 2532ERST 2533 2534DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2535 "-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" 2536 " ACPI table description\n", QEMU_ARCH_I386) 2537SRST 2538``-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]...]`` 2539 Add ACPI table with specified header fields and context from 2540 specified files. For file=, take whole ACPI table from the specified 2541 files, including all ACPI headers (possible overridden by other 2542 options). For data=, only data portion of the table is used, all 2543 header information is specified in the command line. If a SLIC table 2544 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2545 fields will override the same in the RSDT and the FADT (a.k.a. 2546 FACP), in order to ensure the field matches required by the 2547 Microsoft SLIC spec and the ACPI spec. 2548ERST 2549 2550DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2551 "-smbios file=binary\n" 2552 " load SMBIOS entry from binary file\n" 2553 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2554 " [,uefi=on|off]\n" 2555 " specify SMBIOS type 0 fields\n" 2556 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2557 " [,uuid=uuid][,sku=str][,family=str]\n" 2558 " specify SMBIOS type 1 fields\n" 2559 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2560 " [,asset=str][,location=str]\n" 2561 " specify SMBIOS type 2 fields\n" 2562 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2563 " [,sku=str]\n" 2564 " specify SMBIOS type 3 fields\n" 2565 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2566 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2567 " [,processor-id=%d]\n" 2568 " specify SMBIOS type 4 fields\n" 2569 "-smbios type=11[,value=str][,path=filename]\n" 2570 " specify SMBIOS type 11 fields\n" 2571 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2572 " [,asset=str][,part=str][,speed=%d]\n" 2573 " specify SMBIOS type 17 fields\n" 2574 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2575 " specify SMBIOS type 41 fields\n", 2576 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2577SRST 2578``-smbios file=binary`` 2579 Load SMBIOS entry from binary file. 2580 2581``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2582 Specify SMBIOS type 0 fields 2583 2584``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2585 Specify SMBIOS type 1 fields 2586 2587``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2588 Specify SMBIOS type 2 fields 2589 2590``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2591 Specify SMBIOS type 3 fields 2592 2593``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2594 Specify SMBIOS type 4 fields 2595 2596``-smbios type=11[,value=str][,path=filename]`` 2597 Specify SMBIOS type 11 fields 2598 2599 This argument can be repeated multiple times, and values are added in the order they are parsed. 2600 Applications intending to use OEM strings data are encouraged to use their application name as 2601 a prefix for the value string. This facilitates passing information for multiple applications 2602 concurrently. 2603 2604 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2605 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2606 2607 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2608 the SMBIOS table in the order in which they appear. 2609 2610 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2611 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2612 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2613 data set, for example, by specifying the serial ID of a block device. 2614 2615 An example passing three strings is 2616 2617 .. parsed-literal:: 2618 2619 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2620 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2621 path=/some/file/with/oemstringsdata.txt 2622 2623 In the guest OS this is visible with the ``dmidecode`` command 2624 2625 .. parsed-literal:: 2626 2627 $ dmidecode -t 11 2628 Handle 0x0E00, DMI type 11, 5 bytes 2629 OEM Strings 2630 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2631 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2632 String 3: myapp:some extra data 2633 2634 2635``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2636 Specify SMBIOS type 17 fields 2637 2638``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2639 Specify SMBIOS type 41 fields 2640 2641 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2642 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2643 position on the PCI bus. 2644 2645 Here is an example of use: 2646 2647 .. parsed-literal:: 2648 2649 -netdev user,id=internet \\ 2650 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2651 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2652 2653 In the guest OS, the device should then appear as ``eno1``: 2654 2655 ..parsed-literal:: 2656 2657 $ ip -brief l 2658 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2659 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2660 2661 Currently, the PCI device has to be attached to the root bus. 2662 2663ERST 2664 2665DEFHEADING() 2666 2667DEFHEADING(Network options:) 2668 2669DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2670#ifdef CONFIG_SLIRP 2671 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2672 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2673 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2674 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2675 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2676#ifndef _WIN32 2677 "[,smb=dir[,smbserver=addr]]\n" 2678#endif 2679 " configure a user mode network backend with ID 'str',\n" 2680 " its DHCP server and optional services\n" 2681#endif 2682#ifdef _WIN32 2683 "-netdev tap,id=str,ifname=name\n" 2684 " configure a host TAP network backend with ID 'str'\n" 2685#else 2686 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2687 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2688 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2689 " [,poll-us=n]\n" 2690 " configure a host TAP network backend with ID 'str'\n" 2691 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2692 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2693 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2694 " to deconfigure it\n" 2695 " use '[down]script=no' to disable script execution\n" 2696 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2697 " configure it\n" 2698 " use 'fd=h' to connect to an already opened TAP interface\n" 2699 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2700 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2701 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2702 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2703 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2704 " use vhost=on to enable experimental in kernel accelerator\n" 2705 " (only has effect for virtio guests which use MSIX)\n" 2706 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2707 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2708 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2709 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2710 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2711 " spent on busy polling for vhost net\n" 2712 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2713 " configure a host TAP network backend with ID 'str' that is\n" 2714 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2715 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2716#endif 2717#ifdef __linux__ 2718 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2719 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2720 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2721 " [,rxcookie=rxcookie][,offset=offset]\n" 2722 " configure a network backend with ID 'str' connected to\n" 2723 " an Ethernet over L2TPv3 pseudowire.\n" 2724 " Linux kernel 3.3+ as well as most routers can talk\n" 2725 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2726 " VM to a router and even VM to Host. It is a nearly-universal\n" 2727 " standard (RFC3931). Note - this implementation uses static\n" 2728 " pre-configured tunnels (same as the Linux kernel).\n" 2729 " use 'src=' to specify source address\n" 2730 " use 'dst=' to specify destination address\n" 2731 " use 'udp=on' to specify udp encapsulation\n" 2732 " use 'srcport=' to specify source udp port\n" 2733 " use 'dstport=' to specify destination udp port\n" 2734 " use 'ipv6=on' to force v6\n" 2735 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2736 " well as a weak security measure\n" 2737 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2738 " use 'txcookie=0x012345678' to specify a txcookie\n" 2739 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2740 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2741 " use 'pincounter=on' to work around broken counter handling in peer\n" 2742 " use 'offset=X' to add an extra offset between header and data\n" 2743#endif 2744 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2745 " configure a network backend to connect to another network\n" 2746 " using a socket connection\n" 2747 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2748 " configure a network backend to connect to a multicast maddr and port\n" 2749 " use 'localaddr=addr' to specify the host address to send packets from\n" 2750 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2751 " configure a network backend to connect to another network\n" 2752 " using an UDP tunnel\n" 2753#ifdef CONFIG_VDE 2754 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2755 " configure a network backend to connect to port 'n' of a vde switch\n" 2756 " running on host and listening for incoming connections on 'socketpath'.\n" 2757 " Use group 'groupname' and mode 'octalmode' to change default\n" 2758 " ownership and permissions for communication port.\n" 2759#endif 2760#ifdef CONFIG_NETMAP 2761 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2762 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2763 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2764 " netmap device, defaults to '/dev/netmap')\n" 2765#endif 2766#ifdef CONFIG_POSIX 2767 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2768 " configure a vhost-user network, backed by a chardev 'dev'\n" 2769#endif 2770#ifdef __linux__ 2771 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2772 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2773#endif 2774#ifdef CONFIG_VMNET 2775 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2776 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2777 " configure a vmnet network backend in host mode with ID 'str',\n" 2778 " isolate this interface from others with 'isolated',\n" 2779 " configure the address range and choose a subnet mask,\n" 2780 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2781 " vmnet-host interfaces within this isolated network\n" 2782 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2783 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2784 " configure a vmnet network backend in shared mode with ID 'str',\n" 2785 " configure the address range and choose a subnet mask,\n" 2786 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2787 " isolate this interface from others with 'isolated'\n" 2788 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2789 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2790 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2791 " isolate this interface from others with 'isolated'\n" 2792#endif 2793 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2794 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2795DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2796 "-nic [tap|bridge|" 2797#ifdef CONFIG_SLIRP 2798 "user|" 2799#endif 2800#ifdef __linux__ 2801 "l2tpv3|" 2802#endif 2803#ifdef CONFIG_VDE 2804 "vde|" 2805#endif 2806#ifdef CONFIG_NETMAP 2807 "netmap|" 2808#endif 2809#ifdef CONFIG_POSIX 2810 "vhost-user|" 2811#endif 2812#ifdef CONFIG_VMNET 2813 "vmnet-host|vmnet-shared|vmnet-bridged|" 2814#endif 2815 "socket][,option][,...][mac=macaddr]\n" 2816 " initialize an on-board / default host NIC (using MAC address\n" 2817 " macaddr) and connect it to the given host network backend\n" 2818 "-nic none use it alone to have zero network devices (the default is to\n" 2819 " provided a 'user' network connection)\n", 2820 QEMU_ARCH_ALL) 2821DEF("net", HAS_ARG, QEMU_OPTION_net, 2822 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2823 " configure or create an on-board (or machine default) NIC and\n" 2824 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2825 "-net [" 2826#ifdef CONFIG_SLIRP 2827 "user|" 2828#endif 2829 "tap|" 2830 "bridge|" 2831#ifdef CONFIG_VDE 2832 "vde|" 2833#endif 2834#ifdef CONFIG_NETMAP 2835 "netmap|" 2836#endif 2837#ifdef CONFIG_VMNET 2838 "vmnet-host|vmnet-shared|vmnet-bridged|" 2839#endif 2840 "socket][,option][,option][,...]\n" 2841 " old way to initialize a host network interface\n" 2842 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2843SRST 2844``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2845 This option is a shortcut for configuring both the on-board 2846 (default) guest NIC hardware and the host network backend in one go. 2847 The host backend options are the same as with the corresponding 2848 ``-netdev`` options below. The guest NIC model can be set with 2849 ``model=modelname``. Use ``model=help`` to list the available device 2850 types. The hardware MAC address can be set with ``mac=macaddr``. 2851 2852 The following two example do exactly the same, to show how ``-nic`` 2853 can be used to shorten the command line length: 2854 2855 .. parsed-literal:: 2856 2857 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2858 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2859 2860``-nic none`` 2861 Indicate that no network devices should be configured. It is used to 2862 override the default configuration (default NIC with "user" host 2863 network backend) which is activated if no other networking options 2864 are provided. 2865 2866``-netdev user,id=id[,option][,option][,...]`` 2867 Configure user mode host network backend which requires no 2868 administrator privilege to run. Valid options are: 2869 2870 ``id=id`` 2871 Assign symbolic name for use in monitor commands. 2872 2873 ``ipv4=on|off and ipv6=on|off`` 2874 Specify that either IPv4 or IPv6 must be enabled. If neither is 2875 specified both protocols are enabled. 2876 2877 ``net=addr[/mask]`` 2878 Set IP network address the guest will see. Optionally specify 2879 the netmask, either in the form a.b.c.d or as number of valid 2880 top-most bits. Default is 10.0.2.0/24. 2881 2882 ``host=addr`` 2883 Specify the guest-visible address of the host. Default is the 2884 2nd IP in the guest network, i.e. x.x.x.2. 2885 2886 ``ipv6-net=addr[/int]`` 2887 Set IPv6 network address the guest will see (default is 2888 fec0::/64). The network prefix is given in the usual hexadecimal 2889 IPv6 address notation. The prefix size is optional, and is given 2890 as the number of valid top-most bits (default is 64). 2891 2892 ``ipv6-host=addr`` 2893 Specify the guest-visible IPv6 address of the host. Default is 2894 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2895 2896 ``restrict=on|off`` 2897 If this option is enabled, the guest will be isolated, i.e. it 2898 will not be able to contact the host and no guest IP packets 2899 will be routed over the host to the outside. This option does 2900 not affect any explicitly set forwarding rules. 2901 2902 ``hostname=name`` 2903 Specifies the client hostname reported by the built-in DHCP 2904 server. 2905 2906 ``dhcpstart=addr`` 2907 Specify the first of the 16 IPs the built-in DHCP server can 2908 assign. Default is the 15th to 31st IP in the guest network, 2909 i.e. x.x.x.15 to x.x.x.31. 2910 2911 ``dns=addr`` 2912 Specify the guest-visible address of the virtual nameserver. The 2913 address must be different from the host address. Default is the 2914 3rd IP in the guest network, i.e. x.x.x.3. 2915 2916 ``ipv6-dns=addr`` 2917 Specify the guest-visible address of the IPv6 virtual 2918 nameserver. The address must be different from the host address. 2919 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2920 2921 ``dnssearch=domain`` 2922 Provides an entry for the domain-search list sent by the 2923 built-in DHCP server. More than one domain suffix can be 2924 transmitted by specifying this option multiple times. If 2925 supported, this will cause the guest to automatically try to 2926 append the given domain suffix(es) in case a domain name can not 2927 be resolved. 2928 2929 Example: 2930 2931 .. parsed-literal:: 2932 2933 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2934 2935 ``domainname=domain`` 2936 Specifies the client domain name reported by the built-in DHCP 2937 server. 2938 2939 ``tftp=dir`` 2940 When using the user mode network stack, activate a built-in TFTP 2941 server. The files in dir will be exposed as the root of a TFTP 2942 server. The TFTP client on the guest must be configured in 2943 binary mode (use the command ``bin`` of the Unix TFTP client). 2944 2945 ``tftp-server-name=name`` 2946 In BOOTP reply, broadcast name as the "TFTP server name" 2947 (RFC2132 option 66). This can be used to advise the guest to 2948 load boot files or configurations from a different server than 2949 the host address. 2950 2951 ``bootfile=file`` 2952 When using the user mode network stack, broadcast file as the 2953 BOOTP filename. In conjunction with ``tftp``, this can be used 2954 to network boot a guest from a local directory. 2955 2956 Example (using pxelinux): 2957 2958 .. parsed-literal:: 2959 2960 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2961 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2962 2963 ``smb=dir[,smbserver=addr]`` 2964 When using the user mode network stack, activate a built-in SMB 2965 server so that Windows OSes can access to the host files in 2966 ``dir`` transparently. The IP address of the SMB server can be 2967 set to addr. By default the 4th IP in the guest network is used, 2968 i.e. x.x.x.4. 2969 2970 In the guest Windows OS, the line: 2971 2972 :: 2973 2974 10.0.2.4 smbserver 2975 2976 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2977 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2978 NT/2000). 2979 2980 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2981 2982 Note that a SAMBA server must be installed on the host OS. 2983 2984 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2985 Redirect incoming TCP or UDP connections to the host port 2986 hostport to the guest IP address guestaddr on guest port 2987 guestport. If guestaddr is not specified, its value is x.x.x.15 2988 (default first address given by the built-in DHCP server). By 2989 specifying hostaddr, the rule can be bound to a specific host 2990 interface. If no connection type is set, TCP is used. This 2991 option can be given multiple times. 2992 2993 For example, to redirect host X11 connection from screen 1 to 2994 guest screen 0, use the following: 2995 2996 .. parsed-literal:: 2997 2998 # on the host 2999 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3000 # this host xterm should open in the guest X11 server 3001 xterm -display :1 3002 3003 To redirect telnet connections from host port 5555 to telnet 3004 port on the guest, use the following: 3005 3006 .. parsed-literal:: 3007 3008 # on the host 3009 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3010 telnet localhost 5555 3011 3012 Then when you use on the host ``telnet localhost 5555``, you 3013 connect to the guest telnet server. 3014 3015 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3016 Forward guest TCP connections to the IP address server on port 3017 port to the character device dev or to a program executed by 3018 cmd:command which gets spawned for each connection. This option 3019 can be given multiple times. 3020 3021 You can either use a chardev directly and have that one used 3022 throughout QEMU's lifetime, like in the following example: 3023 3024 .. parsed-literal:: 3025 3026 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3027 # the guest accesses it 3028 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3029 3030 Or you can execute a command on every TCP connection established 3031 by the guest, so that QEMU behaves similar to an inetd process 3032 for that virtual server: 3033 3034 .. parsed-literal:: 3035 3036 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3037 # and connect the TCP stream to its stdin/stdout 3038 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3039 3040``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3041 Configure a host TAP network backend with ID id. 3042 3043 Use the network script file to configure it and the network script 3044 dfile to deconfigure it. If name is not provided, the OS 3045 automatically provides one. The default network configure script is 3046 ``/etc/qemu-ifup`` and the default network deconfigure script is 3047 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3048 disable script execution. 3049 3050 If running QEMU as an unprivileged user, use the network helper 3051 to configure the TAP interface and attach it to the bridge. 3052 The default network helper executable is 3053 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3054 ``br0``. 3055 3056 ``fd``\ =h can be used to specify the handle of an already opened 3057 host TAP interface. 3058 3059 Examples: 3060 3061 .. parsed-literal:: 3062 3063 #launch a QEMU instance with the default network script 3064 |qemu_system| linux.img -nic tap 3065 3066 .. parsed-literal:: 3067 3068 #launch a QEMU instance with two NICs, each one connected 3069 #to a TAP device 3070 |qemu_system| linux.img \\ 3071 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3072 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3073 3074 .. parsed-literal:: 3075 3076 #launch a QEMU instance with the default network helper to 3077 #connect a TAP device to bridge br0 3078 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3079 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3080 3081``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3082 Connect a host TAP network interface to a host bridge device. 3083 3084 Use the network helper helper to configure the TAP interface and 3085 attach it to the bridge. The default network helper executable is 3086 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3087 ``br0``. 3088 3089 Examples: 3090 3091 .. parsed-literal:: 3092 3093 #launch a QEMU instance with the default network helper to 3094 #connect a TAP device to bridge br0 3095 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3096 3097 .. parsed-literal:: 3098 3099 #launch a QEMU instance with the default network helper to 3100 #connect a TAP device to bridge qemubr0 3101 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3102 3103``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3104 This host network backend can be used to connect the guest's network 3105 to another QEMU virtual machine using a TCP socket connection. If 3106 ``listen`` is specified, QEMU waits for incoming connections on port 3107 (host is optional). ``connect`` is used to connect to another QEMU 3108 instance using the ``listen`` option. ``fd``\ =h specifies an 3109 already opened TCP socket. 3110 3111 Example: 3112 3113 .. parsed-literal:: 3114 3115 # launch a first QEMU instance 3116 |qemu_system| linux.img \\ 3117 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3118 -netdev socket,id=n1,listen=:1234 3119 # connect the network of this instance to the network of the first instance 3120 |qemu_system| linux.img \\ 3121 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3122 -netdev socket,id=n2,connect=127.0.0.1:1234 3123 3124``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3125 Configure a socket host network backend to share the guest's network 3126 traffic with another QEMU virtual machines using a UDP multicast 3127 socket, effectively making a bus for every QEMU with same multicast 3128 address maddr and port. NOTES: 3129 3130 1. Several QEMU can be running on different hosts and share same bus 3131 (assuming correct multicast setup for these hosts). 3132 3133 2. mcast support is compatible with User Mode Linux (argument 3134 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3135 3136 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3137 3138 Example: 3139 3140 .. parsed-literal:: 3141 3142 # launch one QEMU instance 3143 |qemu_system| linux.img \\ 3144 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3145 -netdev socket,id=n1,mcast=230.0.0.1:1234 3146 # launch another QEMU instance on same "bus" 3147 |qemu_system| linux.img \\ 3148 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3149 -netdev socket,id=n2,mcast=230.0.0.1:1234 3150 # launch yet another QEMU instance on same "bus" 3151 |qemu_system| linux.img \\ 3152 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3153 -netdev socket,id=n3,mcast=230.0.0.1:1234 3154 3155 Example (User Mode Linux compat.): 3156 3157 .. parsed-literal:: 3158 3159 # launch QEMU instance (note mcast address selected is UML's default) 3160 |qemu_system| linux.img \\ 3161 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3162 -netdev socket,id=n1,mcast=239.192.168.1:1102 3163 # launch UML 3164 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3165 3166 Example (send packets from host's 1.2.3.4): 3167 3168 .. parsed-literal:: 3169 3170 |qemu_system| linux.img \\ 3171 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3172 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3173 3174``-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]`` 3175 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3176 is a popular protocol to transport Ethernet (and other Layer 2) data 3177 frames between two systems. It is present in routers, firewalls and 3178 the Linux kernel (from version 3.3 onwards). 3179 3180 This transport allows a VM to communicate to another VM, router or 3181 firewall directly. 3182 3183 ``src=srcaddr`` 3184 source address (mandatory) 3185 3186 ``dst=dstaddr`` 3187 destination address (mandatory) 3188 3189 ``udp`` 3190 select udp encapsulation (default is ip). 3191 3192 ``srcport=srcport`` 3193 source udp port. 3194 3195 ``dstport=dstport`` 3196 destination udp port. 3197 3198 ``ipv6`` 3199 force v6, otherwise defaults to v4. 3200 3201 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3202 Cookies are a weak form of security in the l2tpv3 specification. 3203 Their function is mostly to prevent misconfiguration. By default 3204 they are 32 bit. 3205 3206 ``cookie64`` 3207 Set cookie size to 64 bit instead of the default 32 3208 3209 ``counter=off`` 3210 Force a 'cut-down' L2TPv3 with no counter as in 3211 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3212 3213 ``pincounter=on`` 3214 Work around broken counter handling in peer. This may also help 3215 on networks which have packet reorder. 3216 3217 ``offset=offset`` 3218 Add an extra offset between header and data 3219 3220 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3221 the bridge br-lan on the remote Linux host 1.2.3.4: 3222 3223 .. parsed-literal:: 3224 3225 # Setup tunnel on linux host using raw ip as encapsulation 3226 # on 1.2.3.4 3227 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3228 encap udp udp_sport 16384 udp_dport 16384 3229 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3230 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3231 ifconfig vmtunnel0 mtu 1500 3232 ifconfig vmtunnel0 up 3233 brctl addif br-lan vmtunnel0 3234 3235 3236 # on 4.3.2.1 3237 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3238 3239 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3240 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3241 3242``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3243 Configure VDE backend to connect to PORT n of a vde switch running 3244 on host and listening for incoming connections on socketpath. Use 3245 GROUP groupname and MODE octalmode to change default ownership and 3246 permissions for communication port. This option is only available if 3247 QEMU has been compiled with vde support enabled. 3248 3249 Example: 3250 3251 .. parsed-literal:: 3252 3253 # launch vde switch 3254 vde_switch -F -sock /tmp/myswitch 3255 # launch QEMU instance 3256 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3257 3258``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3259 Establish a vhost-user netdev, backed by a chardev id. The chardev 3260 should be a unix domain socket backed one. The vhost-user uses a 3261 specifically defined protocol to pass vhost ioctl replacement 3262 messages to an application on the other end of the socket. On 3263 non-MSIX guests, the feature can be forced with vhostforce. Use 3264 'queues=n' to specify the number of queues to be created for 3265 multiqueue vhost-user. 3266 3267 Example: 3268 3269 :: 3270 3271 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3272 -numa node,memdev=mem \ 3273 -chardev socket,id=chr0,path=/path/to/socket \ 3274 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3275 -device virtio-net-pci,netdev=net0 3276 3277``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3278 Establish a vhost-vdpa netdev. 3279 3280 vDPA device is a device that uses a datapath which complies with 3281 the virtio specifications with a vendor specific control path. 3282 vDPA devices can be both physically located on the hardware or 3283 emulated by software. 3284 3285``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3286 Create a hub port on the emulated hub with ID hubid. 3287 3288 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3289 instead of a single netdev. Alternatively, you can also connect the 3290 hubport to another netdev with ID nd by using the ``netdev=nd`` 3291 option. 3292 3293``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3294 Legacy option to configure or create an on-board (or machine 3295 default) Network Interface Card(NIC) and connect it either to the 3296 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3297 If model is omitted, then the default NIC model associated with the 3298 machine type is used. Note that the default NIC model may change in 3299 future QEMU releases, so it is highly recommended to always specify 3300 a model. Optionally, the MAC address can be changed to mac, the 3301 device address set to addr (PCI cards only), and a name can be 3302 assigned for use in monitor commands. Optionally, for PCI cards, you 3303 can specify the number v of MSI-X vectors that the card should have; 3304 this option currently only affects virtio cards; set v = 0 to 3305 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3306 created. QEMU can emulate several different models of network card. 3307 Use ``-net nic,model=help`` for a list of available devices for your 3308 target. 3309 3310``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3311 Configure a host network backend (with the options corresponding to 3312 the same ``-netdev`` option) and connect it to the emulated hub 0 3313 (the default hub). Use name to specify the name of the hub port. 3314ERST 3315 3316DEFHEADING() 3317 3318DEFHEADING(Character device options:) 3319 3320DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3321 "-chardev help\n" 3322 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3323 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3324 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3325 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3326 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3327 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3328 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3329 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3330 " [,logfile=PATH][,logappend=on|off]\n" 3331 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3332 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3333 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3334 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3335 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3336 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3337#ifdef _WIN32 3338 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3339 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3340#else 3341 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3342 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3343#endif 3344#ifdef CONFIG_BRLAPI 3345 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3346#endif 3347#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3348 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3349 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3350 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3351#endif 3352#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3353 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3354 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3355#endif 3356#if defined(CONFIG_SPICE) 3357 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3358 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3359#endif 3360 , QEMU_ARCH_ALL 3361) 3362 3363SRST 3364The general form of a character device option is: 3365 3366``-chardev backend,id=id[,mux=on|off][,options]`` 3367 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3368 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3369 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3370 ``spicevmc``, ``spiceport``. The specific backend will determine the 3371 applicable options. 3372 3373 Use ``-chardev help`` to print all available chardev backend types. 3374 3375 All devices must have an id, which can be any string up to 127 3376 characters long. It is used to uniquely identify this device in 3377 other command line directives. 3378 3379 A character device may be used in multiplexing mode by multiple 3380 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3381 a "1:N" device, and here the "1" end is your specified chardev 3382 backend, and the "N" end is the various parts of QEMU that can talk 3383 to a chardev. If you create a chardev with ``id=myid`` and 3384 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3385 and you can then configure multiple front ends to use that chardev 3386 ID for their input/output. Up to four different front ends can be 3387 connected to a single multiplexed chardev. (Without multiplexing 3388 enabled, a chardev can only be used by a single front end.) For 3389 instance you could use this to allow a single stdio chardev to be 3390 used by two serial ports and the QEMU monitor: 3391 3392 :: 3393 3394 -chardev stdio,mux=on,id=char0 \ 3395 -mon chardev=char0,mode=readline \ 3396 -serial chardev:char0 \ 3397 -serial chardev:char0 3398 3399 You can have more than one multiplexer in a system configuration; 3400 for instance you could have a TCP port multiplexed between UART 0 3401 and UART 1, and stdio multiplexed between the QEMU monitor and a 3402 parallel port: 3403 3404 :: 3405 3406 -chardev stdio,mux=on,id=char0 \ 3407 -mon chardev=char0,mode=readline \ 3408 -parallel chardev:char0 \ 3409 -chardev tcp,...,mux=on,id=char1 \ 3410 -serial chardev:char1 \ 3411 -serial chardev:char1 3412 3413 When you're using a multiplexed character device, some escape 3414 sequences are interpreted in the input. See the chapter about 3415 :ref:`keys in the character backend multiplexer` in the 3416 System Emulation Users Guide for more details. 3417 3418 Note that some other command line options may implicitly create 3419 multiplexed character backends; for instance ``-serial mon:stdio`` 3420 creates a multiplexed stdio backend connected to the serial port and 3421 the QEMU monitor, and ``-nographic`` also multiplexes the console 3422 and the monitor to stdio. 3423 3424 There is currently no support for multiplexing in the other 3425 direction (where a single QEMU front end takes input and output from 3426 multiple chardevs). 3427 3428 Every backend supports the ``logfile`` option, which supplies the 3429 path to a file to record all data transmitted via the backend. The 3430 ``logappend`` option controls whether the log file will be truncated 3431 or appended to when opened. 3432 3433The available backends are: 3434 3435``-chardev null,id=id`` 3436 A void device. This device will not emit any data, and will drop any 3437 data it receives. The null backend does not take any options. 3438 3439``-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]`` 3440 Create a two-way stream socket, which can be either a TCP or a unix 3441 socket. A unix socket will be created if ``path`` is specified. 3442 Behaviour is undefined if TCP options are specified for a unix 3443 socket. 3444 3445 ``server=on|off`` specifies that the socket shall be a listening socket. 3446 3447 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3448 to connect to a listening socket. 3449 3450 ``telnet=on|off`` specifies that traffic on the socket should interpret 3451 telnet escape sequences. 3452 3453 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3454 communication. 3455 3456 ``reconnect`` sets the timeout for reconnecting on non-server 3457 sockets when the remote end goes away. qemu will delay this many 3458 seconds and then attempt to reconnect. Zero disables reconnecting, 3459 and is the default. 3460 3461 ``tls-creds`` requests enablement of the TLS protocol for 3462 encryption, and specifies the id of the TLS credentials to use for 3463 the handshake. The credentials must be previously created with the 3464 ``-object tls-creds`` argument. 3465 3466 ``tls-auth`` provides the ID of the QAuthZ authorization object 3467 against which the client's x509 distinguished name will be 3468 validated. This object is only resolved at time of use, so can be 3469 deleted and recreated on the fly while the chardev server is active. 3470 If missing, it will default to denying access. 3471 3472 TCP and unix socket options are given below: 3473 3474 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3475 ``host`` for a listening socket specifies the local address to 3476 be bound. For a connecting socket species the remote host to 3477 connect to. ``host`` is optional for listening sockets. If not 3478 specified it defaults to ``0.0.0.0``. 3479 3480 ``port`` for a listening socket specifies the local port to be 3481 bound. For a connecting socket specifies the port on the remote 3482 host to connect to. ``port`` can be given as either a port 3483 number or a service name. ``port`` is required. 3484 3485 ``to`` is only relevant to listening sockets. If it is 3486 specified, and ``port`` cannot be bound, QEMU will attempt to 3487 bind to subsequent ports up to and including ``to`` until it 3488 succeeds. ``to`` must be specified as a port number. 3489 3490 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3491 or IPv6 must be used. If neither is specified the socket may 3492 use either protocol. 3493 3494 ``nodelay=on|off`` disables the Nagle algorithm. 3495 3496 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3497 ``path`` specifies the local path of the unix socket. ``path`` 3498 is required. 3499 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3500 rather than the filesystem. Optional, defaults to false. 3501 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3502 rather than the full sun_path length. Optional, defaults to true. 3503 3504``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3505 Sends all traffic from the guest to a remote host over UDP. 3506 3507 ``host`` specifies the remote host to connect to. If not specified 3508 it defaults to ``localhost``. 3509 3510 ``port`` specifies the port on the remote host to connect to. 3511 ``port`` is required. 3512 3513 ``localaddr`` specifies the local address to bind to. If not 3514 specified it defaults to ``0.0.0.0``. 3515 3516 ``localport`` specifies the local port to bind to. If not specified 3517 any available local port will be used. 3518 3519 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3520 If neither is specified the device may use either protocol. 3521 3522``-chardev msmouse,id=id`` 3523 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3524 does not take any options. 3525 3526``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3527 Connect to a QEMU text console. ``vc`` may optionally be given a 3528 specific size. 3529 3530 ``width`` and ``height`` specify the width and height respectively 3531 of the console, in pixels. 3532 3533 ``cols`` and ``rows`` specify that the console be sized to fit a 3534 text console with the given dimensions. 3535 3536``-chardev ringbuf,id=id[,size=size]`` 3537 Create a ring buffer with fixed size ``size``. size must be a power 3538 of two and defaults to ``64K``. 3539 3540``-chardev file,id=id,path=path`` 3541 Log all traffic received from the guest to a file. 3542 3543 ``path`` specifies the path of the file to be opened. This file will 3544 be created if it does not already exist, and overwritten if it does. 3545 ``path`` is required. 3546 3547``-chardev pipe,id=id,path=path`` 3548 Create a two-way connection to the guest. The behaviour differs 3549 slightly between Windows hosts and other hosts: 3550 3551 On Windows, a single duplex pipe will be created at 3552 ``\\.pipe\path``. 3553 3554 On other hosts, 2 pipes will be created called ``path.in`` and 3555 ``path.out``. Data written to ``path.in`` will be received by the 3556 guest. Data written by the guest can be read from ``path.out``. QEMU 3557 will not create these fifos, and requires them to be present. 3558 3559 ``path`` forms part of the pipe path as described above. ``path`` is 3560 required. 3561 3562``-chardev console,id=id`` 3563 Send traffic from the guest to QEMU's standard output. ``console`` 3564 does not take any options. 3565 3566 ``console`` is only available on Windows hosts. 3567 3568``-chardev serial,id=id,path=path`` 3569 Send traffic from the guest to a serial device on the host. 3570 3571 On Unix hosts serial will actually accept any tty device, not only 3572 serial lines. 3573 3574 ``path`` specifies the name of the serial device to open. 3575 3576``-chardev pty,id=id`` 3577 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3578 does not take any options. 3579 3580 ``pty`` is not available on Windows hosts. 3581 3582``-chardev stdio,id=id[,signal=on|off]`` 3583 Connect to standard input and standard output of the QEMU process. 3584 3585 ``signal`` controls if signals are enabled on the terminal, that 3586 includes exiting QEMU with the key sequence Control-c. This option 3587 is enabled by default, use ``signal=off`` to disable it. 3588 3589``-chardev braille,id=id`` 3590 Connect to a local BrlAPI server. ``braille`` does not take any 3591 options. 3592 3593``-chardev tty,id=id,path=path`` 3594 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3595 and DragonFlyBSD hosts. It is an alias for ``serial``. 3596 3597 ``path`` specifies the path to the tty. ``path`` is required. 3598 3599``-chardev parallel,id=id,path=path`` 3600 \ 3601``-chardev parport,id=id,path=path`` 3602 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3603 hosts. 3604 3605 Connect to a local parallel port. 3606 3607 ``path`` specifies the path to the parallel port device. ``path`` is 3608 required. 3609 3610``-chardev spicevmc,id=id,debug=debug,name=name`` 3611 ``spicevmc`` is only available when spice support is built in. 3612 3613 ``debug`` debug level for spicevmc 3614 3615 ``name`` name of spice channel to connect to 3616 3617 Connect to a spice virtual machine channel, such as vdiport. 3618 3619``-chardev spiceport,id=id,debug=debug,name=name`` 3620 ``spiceport`` is only available when spice support is built in. 3621 3622 ``debug`` debug level for spicevmc 3623 3624 ``name`` name of spice port to connect to 3625 3626 Connect to a spice port, allowing a Spice client to handle the 3627 traffic identified by a name (preferably a fqdn). 3628ERST 3629 3630DEFHEADING() 3631 3632#ifdef CONFIG_TPM 3633DEFHEADING(TPM device options:) 3634 3635DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3636 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3637 " use path to provide path to a character device; default is /dev/tpm0\n" 3638 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3639 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3640 "-tpmdev emulator,id=id,chardev=dev\n" 3641 " configure the TPM device using chardev backend\n", 3642 QEMU_ARCH_ALL) 3643SRST 3644The general form of a TPM device option is: 3645 3646``-tpmdev backend,id=id[,options]`` 3647 The specific backend type will determine the applicable options. The 3648 ``-tpmdev`` option creates the TPM backend and requires a 3649 ``-device`` option that specifies the TPM frontend interface model. 3650 3651 Use ``-tpmdev help`` to print all available TPM backend types. 3652 3653The available backends are: 3654 3655``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3656 (Linux-host only) Enable access to the host's TPM using the 3657 passthrough driver. 3658 3659 ``path`` specifies the path to the host's TPM device, i.e., on a 3660 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3661 default ``/dev/tpm0`` is used. 3662 3663 ``cancel-path`` specifies the path to the host TPM device's sysfs 3664 entry allowing for cancellation of an ongoing TPM command. 3665 ``cancel-path`` is optional and by default QEMU will search for the 3666 sysfs entry to use. 3667 3668 Some notes about using the host's TPM with the passthrough driver: 3669 3670 The TPM device accessed by the passthrough driver must not be used 3671 by any other application on the host. 3672 3673 Since the host's firmware (BIOS/UEFI) has already initialized the 3674 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3675 the TPM again and may therefore not show a TPM-specific menu that 3676 would otherwise allow the user to configure the TPM, e.g., allow the 3677 user to enable/disable or activate/deactivate the TPM. Further, if 3678 TPM ownership is released from within a VM then the host's TPM will 3679 get disabled and deactivated. To enable and activate the TPM again 3680 afterwards, the host has to be rebooted and the user is required to 3681 enter the firmware's menu to enable and activate the TPM. If the TPM 3682 is left disabled and/or deactivated most TPM commands will fail. 3683 3684 To create a passthrough TPM use the following two options: 3685 3686 :: 3687 3688 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3689 3690 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3691 ``tpmdev=tpm0`` in the device option. 3692 3693``-tpmdev emulator,id=id,chardev=dev`` 3694 (Linux-host only) Enable access to a TPM emulator using Unix domain 3695 socket based chardev backend. 3696 3697 ``chardev`` specifies the unique ID of a character device backend 3698 that provides connection to the software TPM server. 3699 3700 To create a TPM emulator backend device with chardev socket backend: 3701 3702 :: 3703 3704 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3705ERST 3706 3707DEFHEADING() 3708 3709#endif 3710 3711DEFHEADING(Boot Image or Kernel specific:) 3712SRST 3713There are broadly 4 ways you can boot a system with QEMU. 3714 3715 - specify a firmware and let it control finding a kernel 3716 - specify a firmware and pass a hint to the kernel to boot 3717 - direct kernel image boot 3718 - manually load files into the guest's address space 3719 3720The third method is useful for quickly testing kernels but as there is 3721no firmware to pass configuration information to the kernel the 3722hardware must either be probeable, the kernel built for the exact 3723configuration or passed some configuration data (e.g. a DTB blob) 3724which tells the kernel what drivers it needs. This exact details are 3725often hardware specific. 3726 3727The final method is the most generic way of loading images into the 3728guest address space and used mostly for ``bare metal`` type 3729development where the reset vectors of the processor are taken into 3730account. 3731 3732ERST 3733 3734SRST 3735 3736For x86 machines and some other architectures ``-bios`` will generally 3737do the right thing with whatever it is given. For other machines the 3738more strict ``-pflash`` option needs an image that is sized for the 3739flash device for the given machine type. 3740 3741Please see the :ref:`system-targets-ref` section of the manual for 3742more detailed documentation. 3743 3744ERST 3745 3746DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3747 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3748SRST 3749``-bios file`` 3750 Set the filename for the BIOS. 3751ERST 3752 3753DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3754 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3755SRST 3756``-pflash file`` 3757 Use file as a parallel flash image. 3758ERST 3759 3760SRST 3761 3762The kernel options were designed to work with Linux kernels although 3763other things (like hypervisors) can be packaged up as a kernel 3764executable image. The exact format of a executable image is usually 3765architecture specific. 3766 3767The way in which the kernel is started (what address it is loaded at, 3768what if any information is passed to it via CPU registers, the state 3769of the hardware when it is started, and so on) is also architecture 3770specific. Typically it follows the specification laid down by the 3771Linux kernel for how kernels for that architecture must be started. 3772 3773ERST 3774 3775DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3776 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3777SRST 3778``-kernel bzImage`` 3779 Use bzImage as kernel image. The kernel can be either a Linux kernel 3780 or in multiboot format. 3781ERST 3782 3783DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3784 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3785SRST 3786``-append cmdline`` 3787 Use cmdline as kernel command line 3788ERST 3789 3790DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3791 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3792SRST 3793``-initrd file`` 3794 Use file as initial ram disk. 3795 3796``-initrd "file1 arg=foo,file2"`` 3797 This syntax is only available with multiboot. 3798 3799 Use file1 and file2 as modules and pass arg=foo as parameter to the 3800 first module. 3801ERST 3802 3803DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3804 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3805SRST 3806``-dtb file`` 3807 Use file as a device tree binary (dtb) image and pass it to the 3808 kernel on boot. 3809ERST 3810 3811SRST 3812 3813Finally you can also manually load images directly into the address 3814space of the guest. This is most useful for developers who already 3815know the layout of their guest and take care to ensure something sane 3816will happen when the reset vector executes. 3817 3818The generic loader can be invoked by using the loader device: 3819 3820``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3821 3822there is also the guest loader which operates in a similar way but 3823tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3824the guest image is: 3825 3826``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3827 3828ERST 3829 3830DEFHEADING() 3831 3832DEFHEADING(Debug/Expert options:) 3833 3834DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3835 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3836 " Policy for handling deprecated management interfaces\n" 3837 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3838 " Policy for handling unstable management interfaces\n", 3839 QEMU_ARCH_ALL) 3840SRST 3841``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3842 Set policy for handling deprecated management interfaces (experimental): 3843 3844 ``deprecated-input=accept`` (default) 3845 Accept deprecated commands and arguments 3846 ``deprecated-input=reject`` 3847 Reject deprecated commands and arguments 3848 ``deprecated-input=crash`` 3849 Crash on deprecated commands and arguments 3850 ``deprecated-output=accept`` (default) 3851 Emit deprecated command results and events 3852 ``deprecated-output=hide`` 3853 Suppress deprecated command results and events 3854 3855 Limitation: covers only syntactic aspects of QMP. 3856 3857``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3858 Set policy for handling unstable management interfaces (experimental): 3859 3860 ``unstable-input=accept`` (default) 3861 Accept unstable commands and arguments 3862 ``unstable-input=reject`` 3863 Reject unstable commands and arguments 3864 ``unstable-input=crash`` 3865 Crash on unstable commands and arguments 3866 ``unstable-output=accept`` (default) 3867 Emit unstable command results and events 3868 ``unstable-output=hide`` 3869 Suppress unstable command results and events 3870 3871 Limitation: covers only syntactic aspects of QMP. 3872ERST 3873 3874DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3875 "-fw_cfg [name=]<name>,file=<file>\n" 3876 " add named fw_cfg entry with contents from file\n" 3877 "-fw_cfg [name=]<name>,string=<str>\n" 3878 " add named fw_cfg entry with contents from string\n", 3879 QEMU_ARCH_ALL) 3880SRST 3881``-fw_cfg [name=]name,file=file`` 3882 Add named fw\_cfg entry with contents from file file. 3883 3884``-fw_cfg [name=]name,string=str`` 3885 Add named fw\_cfg entry with contents from string str. 3886 3887 The terminating NUL character of the contents of str will not be 3888 included as part of the fw\_cfg item data. To insert contents with 3889 embedded NUL characters, you have to use the file parameter. 3890 3891 The fw\_cfg entries are passed by QEMU through to the guest. 3892 3893 Example: 3894 3895 :: 3896 3897 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3898 3899 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3900 from ./my\_blob.bin. 3901ERST 3902 3903DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3904 "-serial dev redirect the serial port to char device 'dev'\n", 3905 QEMU_ARCH_ALL) 3906SRST 3907``-serial dev`` 3908 Redirect the virtual serial port to host character device dev. The 3909 default device is ``vc`` in graphical mode and ``stdio`` in non 3910 graphical mode. 3911 3912 This option can be used several times to simulate up to 4 serial 3913 ports. 3914 3915 Use ``-serial none`` to disable all serial ports. 3916 3917 Available character devices are: 3918 3919 ``vc[:WxH]`` 3920 Virtual console. Optionally, a width and height can be given in 3921 pixel with 3922 3923 :: 3924 3925 vc:800x600 3926 3927 It is also possible to specify width or height in characters: 3928 3929 :: 3930 3931 vc:80Cx24C 3932 3933 ``pty`` 3934 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3935 3936 ``none`` 3937 No device is allocated. 3938 3939 ``null`` 3940 void device 3941 3942 ``chardev:id`` 3943 Use a named character device defined with the ``-chardev`` 3944 option. 3945 3946 ``/dev/XXX`` 3947 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3948 port parameters are set according to the emulated ones. 3949 3950 ``/dev/parportN`` 3951 [Linux only, parallel port only] Use host parallel port N. 3952 Currently SPP and EPP parallel port features can be used. 3953 3954 ``file:filename`` 3955 Write output to filename. No character can be read. 3956 3957 ``stdio`` 3958 [Unix only] standard input/output 3959 3960 ``pipe:filename`` 3961 name pipe filename 3962 3963 ``COMn`` 3964 [Windows only] Use host serial port n 3965 3966 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3967 This implements UDP Net Console. When remote\_host or src\_ip 3968 are not specified they default to ``0.0.0.0``. When not using a 3969 specified src\_port a random port is automatically chosen. 3970 3971 If you just want a simple readonly console you can use 3972 ``netcat`` or ``nc``, by starting QEMU with: 3973 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3974 QEMU writes something to that port it will appear in the 3975 netconsole session. 3976 3977 If you plan to send characters back via netconsole or you want 3978 to stop and start QEMU a lot of times, you should have QEMU use 3979 the same source port each time by using something like ``-serial 3980 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3981 version of netcat which can listen to a TCP port and send and 3982 receive characters via udp. If you have a patched version of 3983 netcat which activates telnet remote echo and single char 3984 transfer, then you can use the following options to set up a 3985 netcat redirector to allow telnet on port 5555 to access the 3986 QEMU port. 3987 3988 ``QEMU Options:`` 3989 -serial udp::4555@:4556 3990 3991 ``netcat options:`` 3992 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3993 3994 ``telnet options:`` 3995 localhost 5555 3996 3997 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3998 The TCP Net Console has two modes of operation. It can send the 3999 serial I/O to a location or wait for a connection from a 4000 location. By default the TCP Net Console is sent to host at the 4001 port. If you use the ``server=on`` option QEMU will wait for a client 4002 socket application to connect to the port before continuing, 4003 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4004 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4005 option only applies if ``server=no`` is set, if the connection goes 4006 down it will attempt to reconnect at the given interval. If host 4007 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4008 time is accepted. You can use ``telnet=on`` to connect to the 4009 corresponding character device. 4010 4011 ``Example to send tcp console to 192.168.0.2 port 4444`` 4012 -serial tcp:192.168.0.2:4444 4013 4014 ``Example to listen and wait on port 4444 for connection`` 4015 -serial tcp::4444,server=on 4016 4017 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4018 -serial tcp:192.168.0.100:4444,server=on,wait=off 4019 4020 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4021 The telnet protocol is used instead of raw tcp sockets. The 4022 options work the same as if you had specified ``-serial tcp``. 4023 The difference is that the port acts like a telnet server or 4024 client using telnet option negotiation. This will also allow you 4025 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4026 supports sending the break sequence. Typically in unix telnet 4027 you do it with Control-] and then type "send break" followed by 4028 pressing the enter key. 4029 4030 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4031 The WebSocket protocol is used instead of raw tcp socket. The 4032 port acts as a WebSocket server. Client mode is not supported. 4033 4034 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4035 A unix domain socket is used instead of a tcp socket. The option 4036 works the same as if you had specified ``-serial tcp`` except 4037 the unix domain socket path is used for connections. 4038 4039 ``mon:dev_string`` 4040 This is a special option to allow the monitor to be multiplexed 4041 onto another serial port. The monitor is accessed with key 4042 sequence of Control-a and then pressing c. dev\_string should be 4043 any one of the serial devices specified above. An example to 4044 multiplex the monitor onto a telnet server listening on port 4045 4444 would be: 4046 4047 ``-serial mon:telnet::4444,server=on,wait=off`` 4048 4049 When the monitor is multiplexed to stdio in this way, Ctrl+C 4050 will not terminate QEMU any more but will be passed to the guest 4051 instead. 4052 4053 ``braille`` 4054 Braille device. This will use BrlAPI to display the braille 4055 output on a real or fake device. 4056 4057 ``msmouse`` 4058 Three button serial mouse. Configure the guest to use Microsoft 4059 protocol. 4060ERST 4061 4062DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4063 "-parallel dev redirect the parallel port to char device 'dev'\n", 4064 QEMU_ARCH_ALL) 4065SRST 4066``-parallel dev`` 4067 Redirect the virtual parallel port to host device dev (same devices 4068 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4069 to use hardware devices connected on the corresponding host parallel 4070 port. 4071 4072 This option can be used several times to simulate up to 3 parallel 4073 ports. 4074 4075 Use ``-parallel none`` to disable all parallel ports. 4076ERST 4077 4078DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4079 "-monitor dev redirect the monitor to char device 'dev'\n", 4080 QEMU_ARCH_ALL) 4081SRST 4082``-monitor dev`` 4083 Redirect the monitor to host device dev (same devices as the serial 4084 port). The default device is ``vc`` in graphical mode and ``stdio`` 4085 in non graphical mode. Use ``-monitor none`` to disable the default 4086 monitor. 4087ERST 4088DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4089 "-qmp dev like -monitor but opens in 'control' mode\n", 4090 QEMU_ARCH_ALL) 4091SRST 4092``-qmp dev`` 4093 Like -monitor but opens in 'control' mode. 4094ERST 4095DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4096 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4097 QEMU_ARCH_ALL) 4098SRST 4099``-qmp-pretty dev`` 4100 Like -qmp but uses pretty JSON formatting. 4101ERST 4102 4103DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4104 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4105SRST 4106``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4107 Setup monitor on chardev name. ``mode=control`` configures 4108 a QMP monitor (a JSON RPC-style protocol) and it is not the 4109 same as HMP, the human monitor that has a "(qemu)" prompt. 4110 ``pretty`` is only valid when ``mode=control``, 4111 turning on JSON pretty printing to ease 4112 human reading and debugging. 4113ERST 4114 4115DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4116 "-debugcon dev redirect the debug console to char device 'dev'\n", 4117 QEMU_ARCH_ALL) 4118SRST 4119``-debugcon dev`` 4120 Redirect the debug console to host device dev (same devices as the 4121 serial port). The debug console is an I/O port which is typically 4122 port 0xe9; writing to that I/O port sends output to this device. The 4123 default device is ``vc`` in graphical mode and ``stdio`` in non 4124 graphical mode. 4125ERST 4126 4127DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4128 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4129SRST 4130``-pidfile file`` 4131 Store the QEMU process PID in file. It is useful if you launch QEMU 4132 from a script. 4133ERST 4134 4135DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4136 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4137SRST 4138``-singlestep`` 4139 Run the emulation in single step mode. 4140ERST 4141 4142DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4143 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4144 QEMU_ARCH_ALL) 4145SRST 4146``--preconfig`` 4147 Pause QEMU for interactive configuration before the machine is 4148 created, which allows querying and configuring properties that will 4149 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4150 exit the preconfig state and move to the next state (i.e. run guest 4151 if -S isn't used or pause the second time if -S is used). This 4152 option is experimental. 4153ERST 4154 4155DEF("S", 0, QEMU_OPTION_S, \ 4156 "-S freeze CPU at startup (use 'c' to start execution)\n", 4157 QEMU_ARCH_ALL) 4158SRST 4159``-S`` 4160 Do not start CPU at startup (you must type 'c' in the monitor). 4161ERST 4162 4163DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4164 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4165 " run qemu with overcommit hints\n" 4166 " mem-lock=on|off controls memory lock support (default: off)\n" 4167 " cpu-pm=on|off controls cpu power management (default: off)\n", 4168 QEMU_ARCH_ALL) 4169SRST 4170``-overcommit mem-lock=on|off`` 4171 \ 4172``-overcommit cpu-pm=on|off`` 4173 Run qemu with hints about host resource overcommit. The default is 4174 to assume that host overcommits all resources. 4175 4176 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4177 (disabled by default). This works when host memory is not 4178 overcommitted and reduces the worst-case latency for guest. 4179 4180 Guest ability to manage power state of host cpus (increasing latency 4181 for other processes on the same host cpu, but decreasing latency for 4182 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4183 works best when host CPU is not overcommitted. When used, host 4184 estimates of CPU cycle and power utilization will be incorrect, not 4185 taking into account guest idle time. 4186ERST 4187 4188DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4189 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4190 " the guest without waiting for gdb to connect; use -S too\n" 4191 " if you want it to not start execution.)\n", 4192 QEMU_ARCH_ALL) 4193SRST 4194``-gdb dev`` 4195 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4196 in the System Emulation Users Guide). Note that this option does not pause QEMU 4197 execution -- if you want QEMU to not start the guest until you 4198 connect with gdb and issue a ``continue`` command, you will need to 4199 also pass the ``-S`` option to QEMU. 4200 4201 The most usual configuration is to listen on a local TCP socket:: 4202 4203 -gdb tcp::3117 4204 4205 but you can specify other backends; UDP, pseudo TTY, or even stdio 4206 are all reasonable use cases. For example, a stdio connection 4207 allows you to start QEMU from within gdb and establish the 4208 connection via a pipe: 4209 4210 .. parsed-literal:: 4211 4212 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4213ERST 4214 4215DEF("s", 0, QEMU_OPTION_s, \ 4216 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4217 QEMU_ARCH_ALL) 4218SRST 4219``-s`` 4220 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4221 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4222ERST 4223 4224DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4225 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4226 QEMU_ARCH_ALL) 4227SRST 4228``-d item1[,...]`` 4229 Enable logging of specified items. Use '-d help' for a list of log 4230 items. 4231ERST 4232 4233DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4234 "-D logfile output log to logfile (default stderr)\n", 4235 QEMU_ARCH_ALL) 4236SRST 4237``-D logfile`` 4238 Output log in logfile instead of to stderr 4239ERST 4240 4241DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4242 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4243 QEMU_ARCH_ALL) 4244SRST 4245``-dfilter range1[,...]`` 4246 Filter debug output to that relevant to a range of target addresses. 4247 The filter spec can be either start+size, start-size or start..end 4248 where start end and size are the addresses and sizes required. For 4249 example: 4250 4251 :: 4252 4253 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4254 4255 Will dump output for any code in the 0x1000 sized block starting at 4256 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4257 another 0x1000 sized block starting at 0xffffffc00005f000. 4258ERST 4259 4260DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4261 "-seed number seed the pseudo-random number generator\n", 4262 QEMU_ARCH_ALL) 4263SRST 4264``-seed number`` 4265 Force the guest to use a deterministic pseudo-random number 4266 generator, seeded with number. This does not affect crypto routines 4267 within the host. 4268ERST 4269 4270DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4271 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4272 QEMU_ARCH_ALL) 4273SRST 4274``-L path`` 4275 Set the directory for the BIOS, VGA BIOS and keymaps. 4276 4277 To list all the data directories, use ``-L help``. 4278ERST 4279 4280DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4281 "-enable-kvm enable KVM full virtualization support\n", 4282 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4283 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4284SRST 4285``-enable-kvm`` 4286 Enable KVM full virtualization support. This option is only 4287 available if KVM support is enabled when compiling. 4288ERST 4289 4290DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4291 "-xen-domid id specify xen guest domain id\n", 4292 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4293DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4294 "-xen-attach attach to existing xen domain\n" 4295 " libxl will use this when starting QEMU\n", 4296 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4297DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4298 "-xen-domid-restrict restrict set of available xen operations\n" 4299 " to specified domain id. (Does not affect\n" 4300 " xenpv machine type).\n", 4301 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4302SRST 4303``-xen-domid id`` 4304 Specify xen guest domain id (XEN only). 4305 4306``-xen-attach`` 4307 Attach to existing xen domain. libxl will use this when starting 4308 QEMU (XEN only). Restrict set of available xen operations to 4309 specified domain id (XEN only). 4310ERST 4311 4312DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4313 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4314SRST 4315``-no-reboot`` 4316 Exit instead of rebooting. 4317ERST 4318 4319DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4320 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4321SRST 4322``-no-shutdown`` 4323 Don't exit QEMU on guest shutdown, but instead only stop the 4324 emulation. This allows for instance switching to monitor to commit 4325 changes to the disk image. 4326ERST 4327 4328DEF("action", HAS_ARG, QEMU_OPTION_action, 4329 "-action reboot=reset|shutdown\n" 4330 " action when guest reboots [default=reset]\n" 4331 "-action shutdown=poweroff|pause\n" 4332 " action when guest shuts down [default=poweroff]\n" 4333 "-action panic=pause|shutdown|exit-failure|none\n" 4334 " action when guest panics [default=shutdown]\n" 4335 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4336 " action when watchdog fires [default=reset]\n", 4337 QEMU_ARCH_ALL) 4338SRST 4339``-action event=action`` 4340 The action parameter serves to modify QEMU's default behavior when 4341 certain guest events occur. It provides a generic method for specifying the 4342 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4343 parameters. 4344 4345 Examples: 4346 4347 ``-action panic=none`` 4348 ``-action reboot=shutdown,shutdown=pause`` 4349 ``-watchdog i6300esb -action watchdog=pause`` 4350 4351ERST 4352 4353DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4354 "-loadvm [tag|id]\n" \ 4355 " start right away with a saved state (loadvm in monitor)\n", 4356 QEMU_ARCH_ALL) 4357SRST 4358``-loadvm file`` 4359 Start right away with a saved state (``loadvm`` in monitor) 4360ERST 4361 4362#ifndef _WIN32 4363DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4364 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4365#endif 4366SRST 4367``-daemonize`` 4368 Daemonize the QEMU process after initialization. QEMU will not 4369 detach from standard IO until it is ready to receive connections on 4370 any of its devices. This option is a useful way for external 4371 programs to launch QEMU without having to cope with initialization 4372 race conditions. 4373ERST 4374 4375DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4376 "-option-rom rom load a file, rom, into the option ROM space\n", 4377 QEMU_ARCH_ALL) 4378SRST 4379``-option-rom file`` 4380 Load the contents of file as an option ROM. This option is useful to 4381 load things like EtherBoot. 4382ERST 4383 4384DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4385 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4386 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4387 QEMU_ARCH_ALL) 4388 4389SRST 4390``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4391 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4392 the current UTC or local time, respectively. ``localtime`` is 4393 required for correct date in MS-DOS or Windows. To start at a 4394 specific point in time, provide datetime in the format 4395 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4396 4397 By default the RTC is driven by the host system time. This allows 4398 using of the RTC as accurate reference clock inside the guest, 4399 specifically if the host time is smoothly following an accurate 4400 external reference clock, e.g. via NTP. If you want to isolate the 4401 guest time from the host, you can set ``clock`` to ``rt`` instead, 4402 which provides a host monotonic clock if host support it. To even 4403 prevent the RTC from progressing during suspension, you can set 4404 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4405 recommended especially in icount mode in order to preserve 4406 determinism; however, note that in icount mode the speed of the 4407 virtual clock is variable and can in general differ from the host 4408 clock. 4409 4410 Enable ``driftfix`` (i386 targets only) if you experience time drift 4411 problems, specifically with Windows' ACPI HAL. This option will try 4412 to figure out how many timer interrupts were not processed by the 4413 Windows guest and will re-inject them. 4414ERST 4415 4416DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4417 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4418 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4419 " instruction, enable aligning the host and virtual clocks\n" \ 4420 " or disable real time cpu sleeping, and optionally enable\n" \ 4421 " record-and-replay mode\n", QEMU_ARCH_ALL) 4422SRST 4423``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4424 Enable virtual instruction counter. The virtual cpu will execute one 4425 instruction every 2^N ns of virtual time. If ``auto`` is specified 4426 then the virtual cpu speed will be automatically adjusted to keep 4427 virtual time within a few seconds of real time. 4428 4429 Note that while this option can give deterministic behavior, it does 4430 not provide cycle accurate emulation. Modern CPUs contain 4431 superscalar out of order cores with complex cache hierarchies. The 4432 number of instructions executed often has little or no correlation 4433 with actual performance. 4434 4435 When the virtual cpu is sleeping, the virtual time will advance at 4436 default speed unless ``sleep=on`` is specified. With 4437 ``sleep=on``, the virtual time will jump to the next timer 4438 deadline instantly whenever the virtual cpu goes to sleep mode and 4439 will not advance if no timer is enabled. This behavior gives 4440 deterministic execution times from the guest point of view. 4441 The default if icount is enabled is ``sleep=off``. 4442 ``sleep=on`` cannot be used together with either ``shift=auto`` 4443 or ``align=on``. 4444 4445 ``align=on`` will activate the delay algorithm which will try to 4446 synchronise the host clock and the virtual clock. The goal is to 4447 have a guest running at the real frequency imposed by the shift 4448 option. Whenever the guest clock is behind the host clock and if 4449 ``align=on`` is specified then we print a message to the user to 4450 inform about the delay. Currently this option does not work when 4451 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4452 shift values for which the guest clock runs ahead of the host clock. 4453 Typically this happens when the shift value is high (how high 4454 depends on the host machine). The default if icount is enabled 4455 is ``align=off``. 4456 4457 When the ``rr`` option is specified deterministic record/replay is 4458 enabled. The ``rrfile=`` option must also be provided to 4459 specify the path to the replay log. In record mode data is written 4460 to this file, and in replay mode it is read back. 4461 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4462 name. In record mode, a new VM snapshot with the given name is created 4463 at the start of execution recording. In replay mode this option 4464 specifies the snapshot name used to load the initial VM state. 4465ERST 4466 4467DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4468 "-watchdog model\n" \ 4469 " enable virtual hardware watchdog [default=none]\n", 4470 QEMU_ARCH_ALL) 4471SRST 4472``-watchdog model`` 4473 Create a virtual hardware watchdog device. Once enabled (by a guest 4474 action), the watchdog must be periodically polled by an agent inside 4475 the guest or else the guest will be restarted. Choose a model for 4476 which your guest has drivers. 4477 4478 The model is the model of hardware watchdog to emulate. Use 4479 ``-watchdog help`` to list available hardware models. Only one 4480 watchdog can be enabled for a guest. 4481 4482 The following models may be available: 4483 4484 ``ib700`` 4485 iBASE 700 is a very simple ISA watchdog with a single timer. 4486 4487 ``i6300esb`` 4488 Intel 6300ESB I/O controller hub is a much more featureful 4489 PCI-based dual-timer watchdog. 4490 4491 ``diag288`` 4492 A virtual watchdog for s390x backed by the diagnose 288 4493 hypercall (currently KVM only). 4494ERST 4495 4496DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4497 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4498 " action when watchdog fires [default=reset]\n", 4499 QEMU_ARCH_ALL) 4500SRST 4501``-watchdog-action action`` 4502 The action controls what QEMU will do when the watchdog timer 4503 expires. The default is ``reset`` (forcefully reset the guest). 4504 Other possible actions are: ``shutdown`` (attempt to gracefully 4505 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4506 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4507 guest), ``debug`` (print a debug message and continue), or ``none`` 4508 (do nothing). 4509 4510 Note that the ``shutdown`` action requires that the guest responds 4511 to ACPI signals, which it may not be able to do in the sort of 4512 situations where the watchdog would have expired, and thus 4513 ``-watchdog-action shutdown`` is not recommended for production use. 4514 4515 Examples: 4516 4517 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4518 4519ERST 4520 4521DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4522 "-echr chr set terminal escape character instead of ctrl-a\n", 4523 QEMU_ARCH_ALL) 4524SRST 4525``-echr numeric_ascii_value`` 4526 Change the escape character used for switching to the monitor when 4527 using monitor and serial sharing. The default is ``0x01`` when using 4528 the ``-nographic`` option. ``0x01`` is equal to pressing 4529 ``Control-a``. You can select a different character from the ascii 4530 control keys where 1 through 26 map to Control-a through Control-z. 4531 For instance you could use the either of the following to change the 4532 escape character to Control-t. 4533 4534 ``-echr 0x14``; \ ``-echr 20`` 4535 4536ERST 4537 4538DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4539 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4540 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4541 "-incoming unix:socketpath\n" \ 4542 " prepare for incoming migration, listen on\n" \ 4543 " specified protocol and socket address\n" \ 4544 "-incoming fd:fd\n" \ 4545 "-incoming exec:cmdline\n" \ 4546 " accept incoming migration on given file descriptor\n" \ 4547 " or from given external command\n" \ 4548 "-incoming defer\n" \ 4549 " wait for the URI to be specified via migrate_incoming\n", 4550 QEMU_ARCH_ALL) 4551SRST 4552``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4553 \ 4554``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4555 Prepare for incoming migration, listen on a given tcp port. 4556 4557``-incoming unix:socketpath`` 4558 Prepare for incoming migration, listen on a given unix socket. 4559 4560``-incoming fd:fd`` 4561 Accept incoming migration from a given filedescriptor. 4562 4563``-incoming exec:cmdline`` 4564 Accept incoming migration as an output from specified external 4565 command. 4566 4567``-incoming defer`` 4568 Wait for the URI to be specified via migrate\_incoming. The monitor 4569 can be used to change settings (such as migration parameters) prior 4570 to issuing the migrate\_incoming to allow the migration to begin. 4571ERST 4572 4573DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4574 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4575SRST 4576``-only-migratable`` 4577 Only allow migratable devices. Devices will not be allowed to enter 4578 an unmigratable state. 4579ERST 4580 4581DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4582 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4583SRST 4584``-nodefaults`` 4585 Don't create default devices. Normally, QEMU sets the default 4586 devices like serial port, parallel port, virtual console, monitor 4587 device, VGA adapter, floppy and CD-ROM drive and others. The 4588 ``-nodefaults`` option will disable all those default devices. 4589ERST 4590 4591#ifndef _WIN32 4592DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4593 "-chroot dir chroot to dir just before starting the VM\n", 4594 QEMU_ARCH_ALL) 4595#endif 4596SRST 4597``-chroot dir`` 4598 Immediately before starting guest execution, chroot to the specified 4599 directory. Especially useful in combination with -runas. 4600ERST 4601 4602#ifndef _WIN32 4603DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4604 "-runas user change to user id user just before starting the VM\n" \ 4605 " user can be numeric uid:gid instead\n", 4606 QEMU_ARCH_ALL) 4607#endif 4608SRST 4609``-runas user`` 4610 Immediately before starting guest execution, drop root privileges, 4611 switching to the specified user. 4612ERST 4613 4614DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4615 "-prom-env variable=value\n" 4616 " set OpenBIOS nvram variables\n", 4617 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4618SRST 4619``-prom-env variable=value`` 4620 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4621 4622 :: 4623 4624 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4625 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4626 4627 :: 4628 4629 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4630 -prom-env 'boot-device=hd:2,\yaboot' \ 4631 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4632ERST 4633DEF("semihosting", 0, QEMU_OPTION_semihosting, 4634 "-semihosting semihosting mode\n", 4635 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4636 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4637SRST 4638``-semihosting`` 4639 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4640 4641 Note that this allows guest direct access to the host filesystem, so 4642 should only be used with a trusted guest OS. 4643 4644 See the -semihosting-config option documentation for further 4645 information about the facilities this enables. 4646ERST 4647DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4648 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4649 " semihosting configuration\n", 4650QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4651QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4652SRST 4653``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4654 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4655 only). 4656 4657 Note that this allows guest direct access to the host filesystem, so 4658 should only be used with a trusted guest OS. 4659 4660 On Arm this implements the standard semihosting API, version 2.0. 4661 4662 On M68K this implements the "ColdFire GDB" interface used by 4663 libgloss. 4664 4665 Xtensa semihosting provides basic file IO calls, such as 4666 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4667 linux platform "sim" use this interface. 4668 4669 On RISC-V this implements the standard semihosting API, version 0.2. 4670 4671 ``target=native|gdb|auto`` 4672 Defines where the semihosting calls will be addressed, to QEMU 4673 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4674 means ``gdb`` during debug sessions and ``native`` otherwise. 4675 4676 ``chardev=str1`` 4677 Send the output to a chardev backend output for native or auto 4678 output when not in gdb 4679 4680 ``userspace=on|off`` 4681 Allows code running in guest userspace to access the semihosting 4682 interface. The default is that only privileged guest code can 4683 make semihosting calls. Note that setting ``userspace=on`` should 4684 only be used if all guest code is trusted (for example, in 4685 bare-metal test case code). 4686 4687 ``arg=str1,arg=str2,...`` 4688 Allows the user to pass input arguments, and can be used 4689 multiple times to build up a list. The old-style 4690 ``-kernel``/``-append`` method of passing a command line is 4691 still supported for backward compatibility. If both the 4692 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4693 specified, the former is passed to semihosting as it always 4694 takes precedence. 4695ERST 4696DEF("old-param", 0, QEMU_OPTION_old_param, 4697 "-old-param old param mode\n", QEMU_ARCH_ARM) 4698SRST 4699``-old-param`` 4700 Old param mode (ARM only). 4701ERST 4702 4703DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4704 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4705 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4706 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4707 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4708 " by the kernel, but typically no longer used by modern\n" \ 4709 " C library implementations.\n" \ 4710 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4711 " to elevate privileges using set*uid|gid system calls.\n" \ 4712 " The value 'children' will deny set*uid|gid system calls for\n" \ 4713 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4714 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4715 " blocking *fork and execve\n" \ 4716 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4717 QEMU_ARCH_ALL) 4718SRST 4719``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4720 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4721 filtering and 'off' will disable it. The default is 'off'. 4722 4723 ``obsolete=string`` 4724 Enable Obsolete system calls 4725 4726 ``elevateprivileges=string`` 4727 Disable set\*uid\|gid system calls 4728 4729 ``spawn=string`` 4730 Disable \*fork and execve 4731 4732 ``resourcecontrol=string`` 4733 Disable process affinity and schedular priority 4734ERST 4735 4736DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4737 "-readconfig <file>\n" 4738 " read config file\n", QEMU_ARCH_ALL) 4739SRST 4740``-readconfig file`` 4741 Read device configuration from file. This approach is useful when 4742 you want to spawn QEMU process with many command line options but 4743 you don't want to exceed the command line character limit. 4744ERST 4745 4746DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4747 "-no-user-config\n" 4748 " do not load default user-provided config files at startup\n", 4749 QEMU_ARCH_ALL) 4750SRST 4751``-no-user-config`` 4752 The ``-no-user-config`` option makes QEMU not load any of the 4753 user-provided config files on sysconfdir. 4754ERST 4755 4756DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4757 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4758 " specify tracing options\n", 4759 QEMU_ARCH_ALL) 4760SRST 4761``-trace [[enable=]pattern][,events=file][,file=file]`` 4762 .. include:: ../qemu-option-trace.rst.inc 4763 4764ERST 4765DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4766 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4767 " load a plugin\n", 4768 QEMU_ARCH_ALL) 4769SRST 4770``-plugin file=file[,argname=argvalue]`` 4771 Load a plugin. 4772 4773 ``file=file`` 4774 Load the given plugin from a shared library file. 4775 4776 ``argname=argvalue`` 4777 Argument passed to the plugin. (Can be given multiple times.) 4778ERST 4779 4780HXCOMM Internal use 4781DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4782DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4783 4784DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4785 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4786 " control error message format\n" 4787 " timestamp=on enables timestamps (default: off)\n" 4788 " guest-name=on enables guest name prefix but only if\n" 4789 " -name guest option is set (default: off)\n", 4790 QEMU_ARCH_ALL) 4791SRST 4792``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4793 Control error message format. 4794 4795 ``timestamp=on|off`` 4796 Prefix messages with a timestamp. Default is off. 4797 4798 ``guest-name=on|off`` 4799 Prefix messages with guest name but only if -name guest option is set 4800 otherwise the option is ignored. Default is off. 4801ERST 4802 4803DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4804 "-dump-vmstate <file>\n" 4805 " Output vmstate information in JSON format to file.\n" 4806 " Use the scripts/vmstate-static-checker.py file to\n" 4807 " check for possible regressions in migration code\n" 4808 " by comparing two such vmstate dumps.\n", 4809 QEMU_ARCH_ALL) 4810SRST 4811``-dump-vmstate file`` 4812 Dump json-encoded vmstate information for current machine type to 4813 file in file 4814ERST 4815 4816DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4817 "-enable-sync-profile\n" 4818 " enable synchronization profiling\n", 4819 QEMU_ARCH_ALL) 4820SRST 4821``-enable-sync-profile`` 4822 Enable synchronization profiling. 4823ERST 4824 4825DEFHEADING() 4826 4827DEFHEADING(Generic object creation:) 4828 4829DEF("object", HAS_ARG, QEMU_OPTION_object, 4830 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4831 " create a new object of type TYPENAME setting properties\n" 4832 " in the order they are specified. Note that the 'id'\n" 4833 " property must be set. These objects are placed in the\n" 4834 " '/objects' path.\n", 4835 QEMU_ARCH_ALL) 4836SRST 4837``-object typename[,prop1=value1,...]`` 4838 Create a new object of type typename setting properties in the order 4839 they are specified. Note that the 'id' property must be set. These 4840 objects are placed in the '/objects' path. 4841 4842 ``-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`` 4843 Creates a memory file backend object, which can be used to back 4844 the guest RAM with huge pages. 4845 4846 The ``id`` parameter is a unique ID that will be used to 4847 reference this memory region in other parameters, e.g. ``-numa``, 4848 ``-device nvdimm``, etc. 4849 4850 The ``size`` option provides the size of the memory region, and 4851 accepts common suffixes, e.g. ``500M``. 4852 4853 The ``mem-path`` provides the path to either a shared memory or 4854 huge page filesystem mount. 4855 4856 The ``share`` boolean option determines whether the memory 4857 region is marked as private to QEMU, or shared. The latter 4858 allows a co-operating external process to access the QEMU memory 4859 region. 4860 4861 The ``share`` is also required for pvrdma devices due to 4862 limitations in the RDMA API provided by Linux. 4863 4864 Setting share=on might affect the ability to configure NUMA 4865 bindings for the memory backend under some circumstances, see 4866 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4867 source tree for additional details. 4868 4869 Setting the ``discard-data`` boolean option to on indicates that 4870 file contents can be destroyed when QEMU exits, to avoid 4871 unnecessarily flushing data to the backing file. Note that 4872 ``discard-data`` is only an optimization, and QEMU might not 4873 discard file contents if it aborts unexpectedly or is terminated 4874 using SIGKILL. 4875 4876 The ``merge`` boolean option enables memory merge, also known as 4877 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4878 the pages for memory deduplication. 4879 4880 Setting the ``dump`` boolean option to off excludes the memory 4881 from core dumps. This feature is also known as MADV\_DONTDUMP. 4882 4883 The ``prealloc`` boolean option enables memory preallocation. 4884 4885 The ``host-nodes`` option binds the memory range to a list of 4886 NUMA host nodes. 4887 4888 The ``policy`` option sets the NUMA policy to one of the 4889 following values: 4890 4891 ``default`` 4892 default host policy 4893 4894 ``preferred`` 4895 prefer the given host node list for allocation 4896 4897 ``bind`` 4898 restrict memory allocation to the given host node list 4899 4900 ``interleave`` 4901 interleave memory allocations across the given host node 4902 list 4903 4904 The ``align`` option specifies the base address alignment when 4905 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4906 ``2M``. Some backend store specified by ``mem-path`` requires an 4907 alignment different than the default one used by QEMU, eg the 4908 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4909 such cases, users can specify the required alignment via this 4910 option. 4911 4912 The ``pmem`` option specifies whether the backing file specified 4913 by ``mem-path`` is in host persistent memory that can be 4914 accessed using the SNIA NVM programming model (e.g. Intel 4915 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4916 operations to guarantee the persistence of its own writes to 4917 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4918 migration). Also, we will map the backend-file with MAP\_SYNC 4919 flag, which ensures the file metadata is in sync for 4920 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4921 requires support from both the host kernel (since Linux kernel 4922 4.15) and the filesystem of ``mem-path`` mounted with DAX 4923 option. 4924 4925 The ``readonly`` option specifies whether the backing file is opened 4926 read-only or read-write (default). 4927 4928 ``-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`` 4929 Creates a memory backend object, which can be used to back the 4930 guest RAM. Memory backend objects offer more control than the 4931 ``-m`` option that is traditionally used to define guest RAM. 4932 Please refer to ``memory-backend-file`` for a description of the 4933 options. 4934 4935 ``-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`` 4936 Creates an anonymous memory file backend object, which allows 4937 QEMU to share the memory with an external process (e.g. when 4938 using vhost-user). The memory is allocated with memfd and 4939 optional sealing. (Linux only) 4940 4941 The ``seal`` option creates a sealed-file, that will block 4942 further resizing the memory ('on' by default). 4943 4944 The ``hugetlb`` option specify the file to be created resides in 4945 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4946 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4947 the hugetlb page size on systems that support multiple hugetlb 4948 page sizes (it must be a power of 2 value supported by the 4949 system). 4950 4951 In some versions of Linux, the ``hugetlb`` option is 4952 incompatible with the ``seal`` option (requires at least Linux 4953 4.16). 4954 4955 Please refer to ``memory-backend-file`` for a description of the 4956 other options. 4957 4958 The ``share`` boolean option is on by default with memfd. 4959 4960 ``-object rng-builtin,id=id`` 4961 Creates a random number generator backend which obtains entropy 4962 from QEMU builtin functions. The ``id`` parameter is a unique ID 4963 that will be used to reference this entropy backend from the 4964 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4965 uses this RNG backend. 4966 4967 ``-object rng-random,id=id,filename=/dev/random`` 4968 Creates a random number generator backend which obtains entropy 4969 from a device on the host. The ``id`` parameter is a unique ID 4970 that will be used to reference this entropy backend from the 4971 ``virtio-rng`` device. The ``filename`` parameter specifies 4972 which file to obtain entropy from and if omitted defaults to 4973 ``/dev/urandom``. 4974 4975 ``-object rng-egd,id=id,chardev=chardevid`` 4976 Creates a random number generator backend which obtains entropy 4977 from an external daemon running on the host. The ``id`` 4978 parameter is a unique ID that will be used to reference this 4979 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4980 parameter is the unique ID of a character device backend that 4981 provides the connection to the RNG daemon. 4982 4983 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4984 Creates a TLS anonymous credentials object, which can be used to 4985 provide TLS support on network backends. The ``id`` parameter is 4986 a unique ID which network backends will use to access the 4987 credentials. The ``endpoint`` is either ``server`` or ``client`` 4988 depending on whether the QEMU network backend that uses the 4989 credentials will be acting as a client or as a server. If 4990 ``verify-peer`` is enabled (the default) then once the handshake 4991 is completed, the peer credentials will be verified, though this 4992 is a no-op for anonymous credentials. 4993 4994 The dir parameter tells QEMU where to find the credential files. 4995 For server endpoints, this directory may contain a file 4996 dh-params.pem providing diffie-hellman parameters to use for the 4997 TLS server. If the file is missing, QEMU will generate a set of 4998 DH parameters at startup. This is a computationally expensive 4999 operation that consumes random pool entropy, so it is 5000 recommended that a persistent set of parameters be generated 5001 upfront and saved. 5002 5003 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5004 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5005 can be used to provide TLS support on network backends. The 5006 ``id`` parameter is a unique ID which network backends will use 5007 to access the credentials. The ``endpoint`` is either ``server`` 5008 or ``client`` depending on whether the QEMU network backend that 5009 uses the credentials will be acting as a client or as a server. 5010 For clients only, ``username`` is the username which will be 5011 sent to the server. If omitted it defaults to "qemu". 5012 5013 The dir parameter tells QEMU where to find the keys file. It is 5014 called "dir/keys.psk" and contains "username:key" pairs. This 5015 file can most easily be created using the GnuTLS ``psktool`` 5016 program. 5017 5018 For server endpoints, dir may also contain a file dh-params.pem 5019 providing diffie-hellman parameters to use for the TLS server. 5020 If the file is missing, QEMU will generate a set of DH 5021 parameters at startup. This is a computationally expensive 5022 operation that consumes random pool entropy, so it is 5023 recommended that a persistent set of parameters be generated up 5024 front and saved. 5025 5026 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5027 Creates a TLS anonymous credentials object, which can be used to 5028 provide TLS support on network backends. The ``id`` parameter is 5029 a unique ID which network backends will use to access the 5030 credentials. The ``endpoint`` is either ``server`` or ``client`` 5031 depending on whether the QEMU network backend that uses the 5032 credentials will be acting as a client or as a server. If 5033 ``verify-peer`` is enabled (the default) then once the handshake 5034 is completed, the peer credentials will be verified. With x509 5035 certificates, this implies that the clients must be provided 5036 with valid client certificates too. 5037 5038 The dir parameter tells QEMU where to find the credential files. 5039 For server endpoints, this directory may contain a file 5040 dh-params.pem providing diffie-hellman parameters to use for the 5041 TLS server. If the file is missing, QEMU will generate a set of 5042 DH parameters at startup. This is a computationally expensive 5043 operation that consumes random pool entropy, so it is 5044 recommended that a persistent set of parameters be generated 5045 upfront and saved. 5046 5047 For x509 certificate credentials the directory will contain 5048 further files providing the x509 certificates. The certificates 5049 must be stored in PEM format, in filenames ca-cert.pem, 5050 ca-crl.pem (optional), server-cert.pem (only servers), 5051 server-key.pem (only servers), client-cert.pem (only clients), 5052 and client-key.pem (only clients). 5053 5054 For the server-key.pem and client-key.pem files which contain 5055 sensitive private keys, it is possible to use an encrypted 5056 version by providing the passwordid parameter. This provides the 5057 ID of a previously created ``secret`` object containing the 5058 password for decryption. 5059 5060 The priority parameter allows to override the global default 5061 priority used by gnutls. This can be useful if the system 5062 administrator needs to use a weaker set of crypto priorities for 5063 QEMU without potentially forcing the weakness onto all 5064 applications. Or conversely if one wants wants a stronger 5065 default for QEMU than for all other applications, they can do 5066 this through this parameter. Its format is a gnutls priority 5067 string as described at 5068 https://gnutls.org/manual/html_node/Priority-Strings.html. 5069 5070 ``-object tls-cipher-suites,id=id,priority=priority`` 5071 Creates a TLS cipher suites object, which can be used to control 5072 the TLS cipher/protocol algorithms that applications are permitted 5073 to use. 5074 5075 The ``id`` parameter is a unique ID which frontends will use to 5076 access the ordered list of permitted TLS cipher suites from the 5077 host. 5078 5079 The ``priority`` parameter allows to override the global default 5080 priority used by gnutls. This can be useful if the system 5081 administrator needs to use a weaker set of crypto priorities for 5082 QEMU without potentially forcing the weakness onto all 5083 applications. Or conversely if one wants wants a stronger 5084 default for QEMU than for all other applications, they can do 5085 this through this parameter. Its format is a gnutls priority 5086 string as described at 5087 https://gnutls.org/manual/html_node/Priority-Strings.html. 5088 5089 An example of use of this object is to control UEFI HTTPS Boot. 5090 The tls-cipher-suites object exposes the ordered list of permitted 5091 TLS cipher suites from the host side to the guest firmware, via 5092 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5093 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5094 guest-side TLS. 5095 5096 In the following example, the priority at which the host-side policy 5097 is retrieved is given by the ``priority`` property. 5098 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5099 refer to /etc/crypto-policies/back-ends/gnutls.config. 5100 5101 .. parsed-literal:: 5102 5103 # |qemu_system| \\ 5104 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5105 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5106 5107 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5108 Interval t can't be 0, this filter batches the packet delivery: 5109 all packets arriving in a given interval on netdev netdevid are 5110 delayed until the end of the interval. Interval is in 5111 microseconds. ``status`` is optional that indicate whether the 5112 netfilter is on (enabled) or off (disabled), the default status 5113 for netfilter will be 'on'. 5114 5115 queue all\|rx\|tx is an option that can be applied to any 5116 netfilter. 5117 5118 ``all``: the filter is attached both to the receive and the 5119 transmit queue of the netdev (default). 5120 5121 ``rx``: the filter is attached to the receive queue of the 5122 netdev, where it will receive packets sent to the netdev. 5123 5124 ``tx``: the filter is attached to the transmit queue of the 5125 netdev, where it will receive packets sent by the netdev. 5126 5127 position head\|tail\|id=<id> is an option to specify where the 5128 filter should be inserted in the filter list. It can be applied 5129 to any netfilter. 5130 5131 ``head``: the filter is inserted at the head of the filter list, 5132 before any existing filters. 5133 5134 ``tail``: the filter is inserted at the tail of the filter list, 5135 behind any existing filters (default). 5136 5137 ``id=<id>``: the filter is inserted before or behind the filter 5138 specified by <id>, see the insert option below. 5139 5140 insert behind\|before is an option to specify where to insert 5141 the new filter relative to the one specified with 5142 position=id=<id>. It can be applied to any netfilter. 5143 5144 ``before``: insert before the specified filter. 5145 5146 ``behind``: insert behind the specified filter (default). 5147 5148 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5149 filter-mirror on netdev netdevid,mirror net packet to 5150 chardevchardevid, if it has the vnet\_hdr\_support flag, 5151 filter-mirror will mirror packet with vnet\_hdr\_len. 5152 5153 ``-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]`` 5154 filter-redirector on netdev netdevid,redirect filter's net 5155 packet to chardev chardevid,and redirect indev's packet to 5156 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5157 will redirect packet with vnet\_hdr\_len. Create a 5158 filter-redirector we need to differ outdev id from indev id, id 5159 can not be the same. we can just use indev or outdev, but at 5160 least one of indev or outdev need to be specified. 5161 5162 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5163 Filter-rewriter is a part of COLO project.It will rewrite tcp 5164 packet to secondary from primary to keep secondary tcp 5165 connection,and rewrite tcp packet to primary from secondary make 5166 tcp packet can be handled by client.if it has the 5167 vnet\_hdr\_support flag, we can parse packet with vnet header. 5168 5169 usage: colo secondary: -object 5170 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5171 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5172 filter-rewriter,id=rew0,netdev=hn0,queue=all 5173 5174 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5175 Dump the network traffic on netdev dev to the file specified by 5176 filename. At most len bytes (64k by default) per packet are 5177 stored. The file format is libpcap, so it can be analyzed with 5178 tools such as tcpdump or Wireshark. 5179 5180 ``-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}]`` 5181 Colo-compare gets packet from primary\_in chardevid and 5182 secondary\_in, then compare whether the payload of primary packet 5183 and secondary packet are the same. If same, it will output 5184 primary packet to out\_dev, else it will notify COLO-framework to do 5185 checkpoint and send primary packet to out\_dev. In order to 5186 improve efficiency, we need to put the task of comparison in 5187 another iothread. If it has the vnet\_hdr\_support flag, 5188 colo compare will send/recv packet with vnet\_hdr\_len. 5189 The compare\_timeout=@var{ms} determines the maximum time of the 5190 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5191 is to set the period of scanning expired primary node network packets. 5192 The max\_queue\_size=@var{size} is to set the max compare queue 5193 size depend on user environment. 5194 If user want to use Xen COLO, need to add the notify\_dev to 5195 notify Xen colo-frame to do checkpoint. 5196 5197 COLO-compare must be used with the help of filter-mirror, 5198 filter-redirector and filter-rewriter. 5199 5200 :: 5201 5202 KVM COLO 5203 5204 primary: 5205 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5206 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5207 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5208 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5209 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5210 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5211 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5212 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5213 -object iothread,id=iothread1 5214 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5215 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5216 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5217 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5218 5219 secondary: 5220 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5221 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5222 -chardev socket,id=red0,host=3.3.3.3,port=9003 5223 -chardev socket,id=red1,host=3.3.3.3,port=9004 5224 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5225 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5226 5227 5228 Xen COLO 5229 5230 primary: 5231 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5232 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5233 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5234 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5235 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5236 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5237 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5238 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5239 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5240 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5241 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5242 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5243 -object iothread,id=iothread1 5244 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5245 5246 secondary: 5247 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5248 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5249 -chardev socket,id=red0,host=3.3.3.3,port=9003 5250 -chardev socket,id=red1,host=3.3.3.3,port=9004 5251 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5252 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5253 5254 If you want to know the detail of above command line, you can 5255 read the colo-compare git log. 5256 5257 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5258 Creates a cryptodev backend which executes crypto opreation from 5259 the QEMU cipher APIS. The id parameter is a unique ID that will 5260 be used to reference this cryptodev backend from the 5261 ``virtio-crypto`` device. The queues parameter is optional, 5262 which specify the queue number of cryptodev backend, the default 5263 of queues is 1. 5264 5265 .. parsed-literal:: 5266 5267 # |qemu_system| \\ 5268 [...] \\ 5269 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5270 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5271 [...] 5272 5273 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5274 Creates a vhost-user cryptodev backend, backed by a chardev 5275 chardevid. The id parameter is a unique ID that will be used to 5276 reference this cryptodev backend from the ``virtio-crypto`` 5277 device. The chardev should be a unix domain socket backed one. 5278 The vhost-user uses a specifically defined protocol to pass 5279 vhost ioctl replacement messages to an application on the other 5280 end of the socket. The queues parameter is optional, which 5281 specify the queue number of cryptodev backend for multiqueue 5282 vhost-user, the default of queues is 1. 5283 5284 .. parsed-literal:: 5285 5286 # |qemu_system| \\ 5287 [...] \\ 5288 -chardev socket,id=chardev0,path=/path/to/socket \\ 5289 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5290 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5291 [...] 5292 5293 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5294 \ 5295 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5296 Defines a secret to store a password, encryption key, or some 5297 other sensitive data. The sensitive data can either be passed 5298 directly via the data parameter, or indirectly via the file 5299 parameter. Using the data parameter is insecure unless the 5300 sensitive data is encrypted. 5301 5302 The sensitive data can be provided in raw format (the default), 5303 or base64. When encoded as JSON, the raw format only supports 5304 valid UTF-8 characters, so base64 is recommended for sending 5305 binary data. QEMU will convert from which ever format is 5306 provided to the format it needs internally. eg, an RBD password 5307 can be provided in raw format, even though it will be base64 5308 encoded when passed onto the RBD sever. 5309 5310 For added protection, it is possible to encrypt the data 5311 associated with a secret using the AES-256-CBC cipher. Use of 5312 encryption is indicated by providing the keyid and iv 5313 parameters. The keyid parameter provides the ID of a previously 5314 defined secret that contains the AES-256 decryption key. This 5315 key should be 32-bytes long and be base64 encoded. The iv 5316 parameter provides the random initialization vector used for 5317 encryption of this particular secret and should be a base64 5318 encrypted string of the 16-byte IV. 5319 5320 The simplest (insecure) usage is to provide the secret inline 5321 5322 .. parsed-literal:: 5323 5324 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5325 5326 The simplest secure usage is to provide the secret via a file 5327 5328 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5329 secret,id=sec0,file=mypasswd.txt,format=raw 5330 5331 For greater security, AES-256-CBC should be used. To illustrate 5332 usage, consider the openssl command line tool which can encrypt 5333 the data. Note that when encrypting, the plaintext must be 5334 padded to the cipher block size (32 bytes) using the standard 5335 PKCS#5/6 compatible padding algorithm. 5336 5337 First a master key needs to be created in base64 encoding: 5338 5339 :: 5340 5341 # openssl rand -base64 32 > key.b64 5342 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5343 5344 Each secret to be encrypted needs to have a random 5345 initialization vector generated. These do not need to be kept 5346 secret 5347 5348 :: 5349 5350 # openssl rand -base64 16 > iv.b64 5351 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5352 5353 The secret to be defined can now be encrypted, in this case 5354 we're telling openssl to base64 encode the result, but it could 5355 be left as raw bytes if desired. 5356 5357 :: 5358 5359 # SECRET=$(printf "letmein" | 5360 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5361 5362 When launching QEMU, create a master secret pointing to 5363 ``key.b64`` and specify that to be used to decrypt the user 5364 password. Pass the contents of ``iv.b64`` to the second secret 5365 5366 .. parsed-literal:: 5367 5368 # |qemu_system| \\ 5369 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5370 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5371 data=$SECRET,iv=$(<iv.b64) 5372 5373 ``-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]`` 5374 Create a Secure Encrypted Virtualization (SEV) guest object, 5375 which can be used to provide the guest memory encryption support 5376 on AMD processors. 5377 5378 When memory encryption is enabled, one of the physical address 5379 bit (aka the C-bit) is utilized to mark if a memory page is 5380 protected. The ``cbitpos`` is used to provide the C-bit 5381 position. The C-bit position is Host family dependent hence user 5382 must provide this value. On EPYC, the value should be 47. 5383 5384 When memory encryption is enabled, we loose certain bits in 5385 physical address space. The ``reduced-phys-bits`` is used to 5386 provide the number of bits we loose in physical address space. 5387 Similar to C-bit, the value is Host family dependent. On EPYC, 5388 the value should be 5. 5389 5390 The ``sev-device`` provides the device file to use for 5391 communicating with the SEV firmware running inside AMD Secure 5392 Processor. The default device is '/dev/sev'. If hardware 5393 supports memory encryption then /dev/sev devices are created by 5394 CCP driver. 5395 5396 The ``policy`` provides the guest policy to be enforced by the 5397 SEV firmware and restrict what configuration and operational 5398 commands can be performed on this guest by the hypervisor. The 5399 policy should be provided by the guest owner and is bound to the 5400 guest and cannot be changed throughout the lifetime of the 5401 guest. The default is 0. 5402 5403 If guest ``policy`` allows sharing the key with another SEV 5404 guest then ``handle`` can be use to provide handle of the guest 5405 from which to share the key. 5406 5407 The ``dh-cert-file`` and ``session-file`` provides the guest 5408 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5409 and session parameters are used for establishing a cryptographic 5410 session with the guest owner to negotiate keys used for 5411 attestation. The file must be encoded in base64. 5412 5413 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5414 cmdline to a designated guest firmware page for measured Linux 5415 boot with -kernel. The default is off. (Since 6.2) 5416 5417 e.g to launch a SEV guest 5418 5419 .. parsed-literal:: 5420 5421 # |qemu_system_x86| \\ 5422 ...... \\ 5423 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5424 -machine ...,memory-encryption=sev0 \\ 5425 ..... 5426 5427 ``-object authz-simple,id=id,identity=string`` 5428 Create an authorization object that will control access to 5429 network services. 5430 5431 The ``identity`` parameter is identifies the user and its format 5432 depends on the network service that authorization object is 5433 associated with. For authorizing based on TLS x509 certificates, 5434 the identity must be the x509 distinguished name. Note that care 5435 must be taken to escape any commas in the distinguished name. 5436 5437 An example authorization object to validate a x509 distinguished 5438 name would look like: 5439 5440 .. parsed-literal:: 5441 5442 # |qemu_system| \\ 5443 ... \\ 5444 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5445 ... 5446 5447 Note the use of quotes due to the x509 distinguished name 5448 containing whitespace, and escaping of ','. 5449 5450 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5451 Create an authorization object that will control access to 5452 network services. 5453 5454 The ``filename`` parameter is the fully qualified path to a file 5455 containing the access control list rules in JSON format. 5456 5457 An example set of rules that match against SASL usernames might 5458 look like: 5459 5460 :: 5461 5462 { 5463 "rules": [ 5464 { "match": "fred", "policy": "allow", "format": "exact" }, 5465 { "match": "bob", "policy": "allow", "format": "exact" }, 5466 { "match": "danb", "policy": "deny", "format": "glob" }, 5467 { "match": "dan*", "policy": "allow", "format": "exact" }, 5468 ], 5469 "policy": "deny" 5470 } 5471 5472 When checking access the object will iterate over all the rules 5473 and the first rule to match will have its ``policy`` value 5474 returned as the result. If no rules match, then the default 5475 ``policy`` value is returned. 5476 5477 The rules can either be an exact string match, or they can use 5478 the simple UNIX glob pattern matching to allow wildcards to be 5479 used. 5480 5481 If ``refresh`` is set to true the file will be monitored and 5482 automatically reloaded whenever its content changes. 5483 5484 As with the ``authz-simple`` object, the format of the identity 5485 strings being matched depends on the network service, but is 5486 usually a TLS x509 distinguished name, or a SASL username. 5487 5488 An example authorization object to validate a SASL username 5489 would look like: 5490 5491 .. parsed-literal:: 5492 5493 # |qemu_system| \\ 5494 ... \\ 5495 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5496 ... 5497 5498 ``-object authz-pam,id=id,service=string`` 5499 Create an authorization object that will control access to 5500 network services. 5501 5502 The ``service`` parameter provides the name of a PAM service to 5503 use for authorization. It requires that a file 5504 ``/etc/pam.d/service`` exist to provide the configuration for 5505 the ``account`` subsystem. 5506 5507 An example authorization object to validate a TLS x509 5508 distinguished name would look like: 5509 5510 .. parsed-literal:: 5511 5512 # |qemu_system| \\ 5513 ... \\ 5514 -object authz-pam,id=auth0,service=qemu-vnc \\ 5515 ... 5516 5517 There would then be a corresponding config file for PAM at 5518 ``/etc/pam.d/qemu-vnc`` that contains: 5519 5520 :: 5521 5522 account requisite pam_listfile.so item=user sense=allow \ 5523 file=/etc/qemu/vnc.allow 5524 5525 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5526 of x509 distingished names that are permitted access 5527 5528 :: 5529 5530 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5531 5532 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5533 Creates a dedicated event loop thread that devices can be 5534 assigned to. This is known as an IOThread. By default device 5535 emulation happens in vCPU threads or the main event loop thread. 5536 This can become a scalability bottleneck. IOThreads allow device 5537 emulation and I/O to run on other host CPUs. 5538 5539 The ``id`` parameter is a unique ID that will be used to 5540 reference this IOThread from ``-device ...,iothread=id``. 5541 Multiple devices can be assigned to an IOThread. Note that not 5542 all devices support an ``iothread`` parameter. 5543 5544 The ``query-iothreads`` QMP command lists IOThreads and reports 5545 their thread IDs so that the user can configure host CPU 5546 pinning/affinity. 5547 5548 IOThreads use an adaptive polling algorithm to reduce event loop 5549 latency. Instead of entering a blocking system call to monitor 5550 file descriptors and then pay the cost of being woken up when an 5551 event occurs, the polling algorithm spins waiting for events for 5552 a short time. The algorithm's default parameters are suitable 5553 for many cases but can be adjusted based on knowledge of the 5554 workload and/or host device latency. 5555 5556 The ``poll-max-ns`` parameter is the maximum number of 5557 nanoseconds to busy wait for events. Polling can be disabled by 5558 setting this value to 0. 5559 5560 The ``poll-grow`` parameter is the multiplier used to increase 5561 the polling time when the algorithm detects it is missing events 5562 due to not polling long enough. 5563 5564 The ``poll-shrink`` parameter is the divisor used to decrease 5565 the polling time when the algorithm detects it is spending too 5566 long polling without encountering events. 5567 5568 The ``aio-max-batch`` parameter is the maximum number of requests 5569 in a batch for the AIO engine, 0 means that the engine will use 5570 its default. 5571 5572 The IOThread parameters can be modified at run-time using the 5573 ``qom-set`` command (where ``iothread1`` is the IOThread's 5574 ``id``): 5575 5576 :: 5577 5578 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5579ERST 5580 5581 5582HXCOMM This is the last statement. Insert new options before this line! 5583 5584#undef DEF 5585#undef DEFHEADING 5586#undef ARCHHEADING 5587
