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 QEMU_ARCH_ALL) 41SRST 42``-machine [type=]name[,prop=value[,...]]`` 43 Select the emulated machine by name. Use ``-machine help`` to list 44 available machines. 45 46 For architectures which aim to support live migration compatibility 47 across releases, each release will introduce a new versioned machine 48 type. For example, the 2.8.0 release introduced machine types 49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 50 51 To allow live migration of guests from QEMU version 2.8.0, to QEMU 52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 54 skip multiple intermediate releases when upgrading, new releases of 55 QEMU will support machine types from many previous versions. 56 57 Supported machine properties are: 58 59 ``accel=accels1[:accels2[:...]]`` 60 This is used to enable an accelerator. Depending on the target 61 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 62 By default, tcg is used. If there is more than one accelerator 63 specified, the next one is used if the previous one fails to 64 initialize. 65 66 ``vmport=on|off|auto`` 67 Enables emulation of VMWare IO port, for vmmouse etc. auto says 68 to select the value based on accel. For accel=xen the default is 69 off otherwise the default is on. 70 71 ``dump-guest-core=on|off`` 72 Include guest memory in a core dump. The default is on. 73 74 ``mem-merge=on|off`` 75 Enables or disables memory merge support. This feature, when 76 supported by the host, de-duplicates identical memory pages 77 among VMs instances (enabled by default). 78 79 ``aes-key-wrap=on|off`` 80 Enables or disables AES key wrapping support on s390-ccw hosts. 81 This feature controls whether AES wrapping keys will be created 82 to allow execution of AES cryptographic functions. The default 83 is on. 84 85 ``dea-key-wrap=on|off`` 86 Enables or disables DEA key wrapping support on s390-ccw hosts. 87 This feature controls whether DEA wrapping keys will be created 88 to allow execution of DEA cryptographic functions. The default 89 is on. 90 91 ``nvdimm=on|off`` 92 Enables or disables NVDIMM support. The default is off. 93 94 ``memory-encryption=`` 95 Memory encryption object to use. The default is none. 96 97 ``hmat=on|off`` 98 Enables or disables ACPI Heterogeneous Memory Attribute Table 99 (HMAT) support. The default is off. 100 101 ``memory-backend='id'`` 102 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 103 Allows to use a memory backend as main RAM. 104 105 For example: 106 :: 107 108 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 109 -machine memory-backend=pc.ram 110 -m 512M 111 112 Migration compatibility note: 113 114 * as backend id one shall use value of 'default-ram-id', advertised by 115 machine type (available via ``query-machines`` QMP command), if migration 116 to/from old QEMU (<5.0) is expected. 117 * for machine types 4.0 and older, user shall 118 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 119 if migration to/from old QEMU (<5.0) is expected. 120 121 For example: 122 :: 123 124 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 125 -machine memory-backend=pc.ram 126 -m 512M 127ERST 128 129DEF("M", HAS_ARG, QEMU_OPTION_M, 130 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 131 QEMU_ARCH_ALL) 132 133SRST 134``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 135 Define an SGX EPC section. 136ERST 137 138DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 139 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 140SRST 141``-cpu model`` 142 Select CPU model (``-cpu help`` for list and additional feature 143 selection) 144ERST 145 146DEF("accel", HAS_ARG, QEMU_OPTION_accel, 147 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 148 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 149 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 150 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 151 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 152 " split-wx=on|off (enable TCG split w^x mapping)\n" 153 " tb-size=n (TCG translation block cache size)\n" 154 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 155 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 156SRST 157``-accel name[,prop=value[,...]]`` 158 This is used to enable an accelerator. Depending on the target 159 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 160 default, tcg is used. If there is more than one accelerator 161 specified, the next one is used if the previous one fails to 162 initialize. 163 164 ``igd-passthru=on|off`` 165 When Xen is in use, this option controls whether Intel 166 integrated graphics devices can be passed through to the guest 167 (default=off) 168 169 ``kernel-irqchip=on|off|split`` 170 Controls KVM in-kernel irqchip support. The default is full 171 acceleration of the interrupt controllers. On x86, split irqchip 172 reduces the kernel attack surface, at a performance cost for 173 non-MSI interrupts. Disabling the in-kernel irqchip completely 174 is not recommended except for debugging purposes. 175 176 ``kvm-shadow-mem=size`` 177 Defines the size of the KVM shadow MMU. 178 179 ``split-wx=on|off`` 180 Controls the use of split w^x mapping for the TCG code generation 181 buffer. Some operating systems require this to be enabled, and in 182 such a case this will default on. On other operating systems, this 183 will default off, but one may enable this for testing or debugging. 184 185 ``tb-size=n`` 186 Controls the size (in MiB) of the TCG translation block cache. 187 188 ``thread=single|multi`` 189 Controls number of TCG threads. When the TCG is multi-threaded 190 there will be one thread per vCPU therefore taking advantage of 191 additional host cores. The default is to enable multi-threading 192 where both the back-end and front-ends support it and no 193 incompatible TCG features have been enabled (e.g. 194 icount/replay). 195 196 ``dirty-ring-size=n`` 197 When the KVM accelerator is used, it controls the size of the per-vCPU 198 dirty page ring buffer (number of entries for each vCPU). It should 199 be a value that is power of two, and it should be 1024 or bigger (but 200 still less than the maximum value that the kernel supports). 4096 201 could be a good initial value if you have no idea which is the best. 202 Set this value to 0 to disable the feature. By default, this feature 203 is disabled (dirty-ring-size=0). When enabled, KVM will instead 204 record dirty pages in a bitmap. 205 206ERST 207 208DEF("smp", HAS_ARG, QEMU_OPTION_smp, 209 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 210 " set the number of initial CPUs to 'n' [default=1]\n" 211 " maxcpus= maximum number of total CPUs, including\n" 212 " offline CPUs for hotplug, etc\n" 213 " sockets= number of sockets on the machine board\n" 214 " dies= number of dies in one socket\n" 215 " clusters= number of clusters in one die\n" 216 " cores= number of cores in one cluster\n" 217 " threads= number of threads in one core\n" 218 "Note: Different machines may have different subsets of the CPU topology\n" 219 " parameters supported, so the actual meaning of the supported parameters\n" 220 " will vary accordingly. For example, for a machine type that supports a\n" 221 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 222 " sequentially mean as below:\n" 223 " sockets means the number of sockets on the machine board\n" 224 " cores means the number of cores in one socket\n" 225 " threads means the number of threads in one core\n" 226 " For a particular machine type board, an expected CPU topology hierarchy\n" 227 " can be defined through the supported sub-option. Unsupported parameters\n" 228 " can also be provided in addition to the sub-option, but their values\n" 229 " must be set as 1 in the purpose of correct parsing.\n", 230 QEMU_ARCH_ALL) 231SRST 232``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 233 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 234 the machine type board. On boards supporting CPU hotplug, the optional 235 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 236 added at runtime. When both parameters are omitted, the maximum number 237 of CPUs will be calculated from the provided topology members and the 238 initial CPU count will match the maximum number. When only one of them 239 is given then the omitted one will be set to its counterpart's value. 240 Both parameters may be specified, but the maximum number of CPUs must 241 be equal to or greater than the initial CPU count. Product of the 242 CPU topology hierarchy must be equal to the maximum number of CPUs. 243 Both parameters are subject to an upper limit that is determined by 244 the specific machine type chosen. 245 246 To control reporting of CPU topology information, values of the topology 247 parameters can be specified. Machines may only support a subset of the 248 parameters and different machines may have different subsets supported 249 which vary depending on capacity of the corresponding CPU targets. So 250 for a particular machine type board, an expected topology hierarchy can 251 be defined through the supported sub-option. Unsupported parameters can 252 also be provided in addition to the sub-option, but their values must be 253 set as 1 in the purpose of correct parsing. 254 255 Either the initial CPU count, or at least one of the topology parameters 256 must be specified. The specified parameters must be greater than zero, 257 explicit configuration like "cpus=0" is not allowed. Values for any 258 omitted parameters will be computed from those which are given. 259 260 For example, the following sub-option defines a CPU topology hierarchy 261 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 262 core) for a machine that only supports sockets/cores/threads. 263 Some members of the option can be omitted but their values will be 264 automatically computed: 265 266 :: 267 268 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 269 270 The following sub-option defines a CPU topology hierarchy (2 sockets 271 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 272 per core) for PC machines which support sockets/dies/cores/threads. 273 Some members of the option can be omitted but their values will be 274 automatically computed: 275 276 :: 277 278 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 279 280 The following sub-option defines a CPU topology hierarchy (2 sockets 281 totally on the machine, 2 clusters per socket, 2 cores per cluster, 282 2 threads per core) for ARM virt machines which support sockets/clusters 283 /cores/threads. Some members of the option can be omitted but their values 284 will be automatically computed: 285 286 :: 287 288 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 289 290 Historically preference was given to the coarsest topology parameters 291 when computing missing values (ie sockets preferred over cores, which 292 were preferred over threads), however, this behaviour is considered 293 liable to change. Prior to 6.2 the preference was sockets over cores 294 over threads. Since 6.2 the preference is cores over sockets over threads. 295 296 For example, the following option defines a machine board with 2 sockets 297 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 298 299 :: 300 301 -smp 2 302ERST 303 304DEF("numa", HAS_ARG, QEMU_OPTION_numa, 305 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 306 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 307 "-numa dist,src=source,dst=destination,val=distance\n" 308 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 309 "-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" 310 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 311 QEMU_ARCH_ALL) 312SRST 313``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 314 \ 315``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 316 \ 317``-numa dist,src=source,dst=destination,val=distance`` 318 \ 319``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 320 \ 321``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 322 \ 323``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 324 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 325 distance from a source node to a destination node. Set the ACPI 326 Heterogeneous Memory Attributes for the given nodes. 327 328 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 329 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 330 contiguous range of CPU indexes (or a single VCPU if lastcpu is 331 omitted). A non-contiguous set of VCPUs can be represented by 332 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 333 omitted on all nodes, VCPUs are automatically split between them. 334 335 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 336 NUMA node: 337 338 :: 339 340 -numa node,cpus=0-2,cpus=5 341 342 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 343 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 344 assign CPU objects to a node using topology layout properties of 345 CPU. The set of properties is machine specific, and depends on used 346 machine type/'\ ``smp``\ ' options. It could be queried with 347 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 348 property specifies node to which CPU object will be assigned, it's 349 required for node to be declared with '\ ``node``\ ' option before 350 it's used with '\ ``cpu``\ ' option. 351 352 For example: 353 354 :: 355 356 -M pc \ 357 -smp 1,sockets=2,maxcpus=2 \ 358 -numa node,nodeid=0 -numa node,nodeid=1 \ 359 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 360 361 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 362 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 363 a given memory backend device to a node. If '\ ``mem``\ ' and 364 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 365 366 367 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 368 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 369 use it. 370 371 '\ ``initiator``\ ' is an additional option that points to an 372 initiator NUMA node that has best performance (the lowest latency or 373 largest bandwidth) to this NUMA node. Note that this option can be 374 set only when the machine property 'hmat' is set to 'on'. 375 376 Following example creates a machine with 2 NUMA nodes, node 0 has 377 CPU. node 1 has only memory, and its initiator is node 0. Note that 378 because node 0 has CPU, by default the initiator of node 0 is itself 379 and must be itself. 380 381 :: 382 383 -machine hmat=on \ 384 -m 2G,slots=2,maxmem=4G \ 385 -object memory-backend-ram,size=1G,id=m0 \ 386 -object memory-backend-ram,size=1G,id=m1 \ 387 -numa node,nodeid=0,memdev=m0 \ 388 -numa node,nodeid=1,memdev=m1,initiator=0 \ 389 -smp 2,sockets=2,maxcpus=2 \ 390 -numa cpu,node-id=0,socket-id=0 \ 391 -numa cpu,node-id=0,socket-id=1 392 393 source and destination are NUMA node IDs. distance is the NUMA 394 distance from source to destination. The distance from a node to 395 itself is always 10. If any pair of nodes is given a distance, then 396 all pairs must be given distances. Although, when distances are only 397 given in one direction for each pair of nodes, then the distances in 398 the opposite directions are assumed to be the same. If, however, an 399 asymmetrical pair of distances is given for even one node pair, then 400 all node pairs must be provided distance values for both directions, 401 even when they are symmetrical. When a node is unreachable from 402 another node, set the pair's distance to 255. 403 404 Note that the -``numa`` option doesn't allocate any of the specified 405 resources, it just assigns existing resources to NUMA nodes. This 406 means that one still has to use the ``-m``, ``-smp`` options to 407 allocate RAM and VCPUs respectively. 408 409 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 410 Information between initiator and target NUMA nodes in ACPI 411 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 412 create memory requests, usually it has one or more processors. 413 Target NUMA node contains addressable memory. 414 415 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 416 the memory hierarchy of the target NUMA node: if hierarchy is 417 'memory', the structure represents the memory performance; if 418 hierarchy is 'first-level\|second-level\|third-level', this 419 structure represents aggregated performance of memory side caches 420 for each domain. type of 'data-type' is type of data represented by 421 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 422 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 423 the target memory; if 'hierarchy' is 424 'first-level\|second-level\|third-level', 'data-type' is 425 'access\|read\|write' hit latency or 'access\|read\|write' hit 426 bandwidth of the target memory side cache. 427 428 lat is latency value in nanoseconds. bw is bandwidth value, the 429 possible value and units are NUM[M\|G\|T], mean that the bandwidth 430 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 431 used suffix). Note that if latency or bandwidth value is 0, means 432 the corresponding latency or bandwidth information is not provided. 433 434 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 435 belongs. size is the size of memory side cache in bytes. level is 436 the cache level described in this structure, note that the cache 437 level 0 should not be used with '\ ``hmat-cache``\ ' option. 438 associativity is the cache associativity, the possible value is 439 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 440 is the write policy. line is the cache Line size in bytes. 441 442 For example, the following options describe 2 NUMA nodes. Node 0 has 443 2 cpus and a ram, node 1 has only a ram. The processors in node 0 444 access memory in node 0 with access-latency 5 nanoseconds, 445 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 446 memory in NUMA node 1 with access-latency 10 nanoseconds, 447 access-bandwidth is 100 MB/s. And for memory side cache information, 448 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 449 policy is write-back, the cache Line size is 8 bytes: 450 451 :: 452 453 -machine hmat=on \ 454 -m 2G \ 455 -object memory-backend-ram,size=1G,id=m0 \ 456 -object memory-backend-ram,size=1G,id=m1 \ 457 -smp 2,sockets=2,maxcpus=2 \ 458 -numa node,nodeid=0,memdev=m0 \ 459 -numa node,nodeid=1,memdev=m1,initiator=0 \ 460 -numa cpu,node-id=0,socket-id=0 \ 461 -numa cpu,node-id=0,socket-id=1 \ 462 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 463 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 464 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 465 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 466 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 467 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 468ERST 469 470DEF("cxl-fixed-memory-window", HAS_ARG, QEMU_OPTION_cxl_fixed_memory_window, 471 "-cxl-fixed-memory-window targets.0=firsttarget,targets.1=secondtarget,size=size[,interleave-granularity=granularity]\n", 472 QEMU_ARCH_ALL) 473SRST 474``-cxl-fixed-memory-window targets.0=firsttarget,targets.1=secondtarget,size=size[,interleave-granularity=granularity]`` 475 Define a CXL Fixed Memory Window (CFMW). 476 477 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 478 479 They are regions of Host Physical Addresses (HPA) on a system which 480 may be interleaved across one or more CXL host bridges. The system 481 software will assign particular devices into these windows and 482 configure the downstream Host-managed Device Memory (HDM) decoders 483 in root ports, switch ports and devices appropriately to meet the 484 interleave requirements before enabling the memory devices. 485 486 ``targets.X=firsttarget`` provides the mapping to CXL host bridges 487 which may be identified by the id provied in the -device entry. 488 Multiple entries are needed to specify all the targets when 489 the fixed memory window represents interleaved memory. X is the 490 target index from 0. 491 492 ``size=size`` sets the size of the CFMW. This must be a multiple of 493 256MiB. The region will be aligned to 256MiB but the location is 494 platform and configuration dependent. 495 496 ``interleave-granularity=granularity`` sets the granularity of 497 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 498 4096KiB, 8192KiB and 16384KiB granularities supported. 499 500 Example: 501 502 :: 503 504 -cxl-fixed-memory-window targets.0=cxl.0,targets.1=cxl.1,size=128G,interleave-granularity=512k 505 506ERST 507 508DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 509 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 510 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 511SRST 512``-add-fd fd=fd,set=set[,opaque=opaque]`` 513 Add a file descriptor to an fd set. Valid options are: 514 515 ``fd=fd`` 516 This option defines the file descriptor of which a duplicate is 517 added to fd set. The file descriptor cannot be stdin, stdout, or 518 stderr. 519 520 ``set=set`` 521 This option defines the ID of the fd set to add the file 522 descriptor to. 523 524 ``opaque=opaque`` 525 This option defines a free-form string that can be used to 526 describe fd. 527 528 You can open an image using pre-opened file descriptors from an fd 529 set: 530 531 .. parsed-literal:: 532 533 |qemu_system| \\ 534 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 535 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 536 -drive file=/dev/fdset/2,index=0,media=disk 537ERST 538 539DEF("set", HAS_ARG, QEMU_OPTION_set, 540 "-set group.id.arg=value\n" 541 " set <arg> parameter for item <id> of type <group>\n" 542 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 543SRST 544``-set group.id.arg=value`` 545 Set parameter arg for item id of type group 546ERST 547 548DEF("global", HAS_ARG, QEMU_OPTION_global, 549 "-global driver.property=value\n" 550 "-global driver=driver,property=property,value=value\n" 551 " set a global default for a driver property\n", 552 QEMU_ARCH_ALL) 553SRST 554``-global driver.prop=value`` 555 \ 556``-global driver=driver,property=property,value=value`` 557 Set default value of driver's property prop to value, e.g.: 558 559 .. parsed-literal:: 560 561 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 562 563 In particular, you can use this to set driver properties for devices 564 which are created automatically by the machine model. To create a 565 device which is not created automatically and set properties on it, 566 use -``device``. 567 568 -global driver.prop=value is shorthand for -global 569 driver=driver,property=prop,value=value. The longhand syntax works 570 even when driver contains a dot. 571ERST 572 573DEF("boot", HAS_ARG, QEMU_OPTION_boot, 574 "-boot [order=drives][,once=drives][,menu=on|off]\n" 575 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 576 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 577 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 578 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 579 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 580 QEMU_ARCH_ALL) 581SRST 582``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 583 Specify boot order drives as a string of drive letters. Valid drive 584 letters depend on the target architecture. The x86 PC uses: a, b 585 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 586 (Etherboot from network adapter 1-4), hard disk boot is the default. 587 To apply a particular boot order only on the first startup, specify 588 it via ``once``. Note that the ``order`` or ``once`` parameter 589 should not be used together with the ``bootindex`` property of 590 devices, since the firmware implementations normally do not support 591 both at the same time. 592 593 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 594 as firmware/BIOS supports them. The default is non-interactive boot. 595 596 A splash picture could be passed to bios, enabling user to show it 597 as logo, when option splash=sp\_name is given and menu=on, If 598 firmware/BIOS supports them. Currently Seabios for X86 system 599 support it. limitation: The splash file could be a jpeg file or a 600 BMP file in 24 BPP format(true color). The resolution should be 601 supported by the SVGA mode, so the recommended is 320x240, 640x480, 602 800x640. 603 604 A timeout could be passed to bios, guest will pause for rb\_timeout 605 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 606 not reboot, qemu passes '-1' to bios by default. Currently Seabios 607 for X86 system support it. 608 609 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 610 it. This only effects when boot priority is changed by bootindex 611 options. The default is non-strict boot. 612 613 .. parsed-literal:: 614 615 # try to boot from network first, then from hard disk 616 |qemu_system_x86| -boot order=nc 617 # boot from CD-ROM first, switch back to default order after reboot 618 |qemu_system_x86| -boot once=d 619 # boot with a splash picture for 5 seconds. 620 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 621 622 Note: The legacy format '-boot drives' is still supported but its 623 use is discouraged as it may be removed from future versions. 624ERST 625 626DEF("m", HAS_ARG, QEMU_OPTION_m, 627 "-m [size=]megs[,slots=n,maxmem=size]\n" 628 " configure guest RAM\n" 629 " size: initial amount of guest memory\n" 630 " slots: number of hotplug slots (default: none)\n" 631 " maxmem: maximum amount of guest memory (default: none)\n" 632 "NOTE: Some architectures might enforce a specific granularity\n", 633 QEMU_ARCH_ALL) 634SRST 635``-m [size=]megs[,slots=n,maxmem=size]`` 636 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 637 Optionally, a suffix of "M" or "G" can be used to signify a value in 638 megabytes or gigabytes respectively. Optional pair slots, maxmem 639 could be used to set amount of hotpluggable memory slots and maximum 640 amount of memory. Note that maxmem must be aligned to the page size. 641 642 For example, the following command-line sets the guest startup RAM 643 size to 1GB, creates 3 slots to hotplug additional memory and sets 644 the maximum memory the guest can reach to 4GB: 645 646 .. parsed-literal:: 647 648 |qemu_system| -m 1G,slots=3,maxmem=4G 649 650 If slots and maxmem are not specified, memory hotplug won't be 651 enabled and the guest startup RAM will never increase. 652ERST 653 654DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 655 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 656SRST 657``-mem-path path`` 658 Allocate guest RAM from a temporarily created file in path. 659ERST 660 661DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 662 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 663 QEMU_ARCH_ALL) 664SRST 665``-mem-prealloc`` 666 Preallocate memory when using -mem-path. 667ERST 668 669DEF("k", HAS_ARG, QEMU_OPTION_k, 670 "-k language use keyboard layout (for example 'fr' for French)\n", 671 QEMU_ARCH_ALL) 672SRST 673``-k language`` 674 Use keyboard layout language (for example ``fr`` for French). This 675 option is only needed where it is not easy to get raw PC keycodes 676 (e.g. on Macs, with some X11 servers or with a VNC or curses 677 display). You don't normally need to use it on PC/Linux or 678 PC/Windows hosts. 679 680 The available layouts are: 681 682 :: 683 684 ar de-ch es fo fr-ca hu ja mk no pt-br sv 685 da en-gb et fr fr-ch is lt nl pl ru th 686 de en-us fi fr-be hr it lv nl-be pt sl tr 687 688 The default is ``en-us``. 689ERST 690 691 692HXCOMM Deprecated by -audiodev 693DEF("audio-help", 0, QEMU_OPTION_audio_help, 694 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 695 QEMU_ARCH_ALL) 696SRST 697``-audio-help`` 698 Will show the -audiodev equivalent of the currently specified 699 (deprecated) environment variables. 700ERST 701 702DEF("audio", HAS_ARG, QEMU_OPTION_audio, 703 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 704 " specifies the audio backend and device to use;\n" 705 " apart from 'model', options are the same as for -audiodev.\n" 706 " use '-audio model=help' to show possible devices.\n", 707 QEMU_ARCH_ALL) 708SRST 709``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 710 This option is a shortcut for configuring both the guest audio 711 hardware and the host audio backend in one go. 712 The host backend options are the same as with the corresponding 713 ``-audiodev`` options below. The guest hardware model can be set with 714 ``model=modelname``. Use ``model=help`` to list the available device 715 types. 716 717 The following two example do exactly the same, to show how ``-audio`` 718 can be used to shorten the command line length: 719 720 .. parsed-literal:: 721 722 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 723 |qemu_system| -audio pa,model=sb16 724ERST 725 726DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 727 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 728 " specifies the audio backend to use\n" 729 " id= identifier of the backend\n" 730 " timer-period= timer period in microseconds\n" 731 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 732 " in|out.fixed-settings= use fixed settings for host audio\n" 733 " in|out.frequency= frequency to use with fixed settings\n" 734 " in|out.channels= number of channels to use with fixed settings\n" 735 " in|out.format= sample format to use with fixed settings\n" 736 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 737 " in|out.voices= number of voices to use\n" 738 " in|out.buffer-length= length of buffer in microseconds\n" 739 "-audiodev none,id=id,[,prop[=value][,...]]\n" 740 " dummy driver that discards all output\n" 741#ifdef CONFIG_AUDIO_ALSA 742 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 743 " in|out.dev= name of the audio device to use\n" 744 " in|out.period-length= length of period in microseconds\n" 745 " in|out.try-poll= attempt to use poll mode\n" 746 " threshold= threshold (in microseconds) when playback starts\n" 747#endif 748#ifdef CONFIG_AUDIO_COREAUDIO 749 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 750 " in|out.buffer-count= number of buffers\n" 751#endif 752#ifdef CONFIG_AUDIO_DSOUND 753 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 754 " latency= add extra latency to playback in microseconds\n" 755#endif 756#ifdef CONFIG_AUDIO_OSS 757 "-audiodev oss,id=id[,prop[=value][,...]]\n" 758 " in|out.dev= path of the audio device to use\n" 759 " in|out.buffer-count= number of buffers\n" 760 " in|out.try-poll= attempt to use poll mode\n" 761 " try-mmap= try using memory mapped access\n" 762 " exclusive= open device in exclusive mode\n" 763 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 764#endif 765#ifdef CONFIG_AUDIO_PA 766 "-audiodev pa,id=id[,prop[=value][,...]]\n" 767 " server= PulseAudio server address\n" 768 " in|out.name= source/sink device name\n" 769 " in|out.latency= desired latency in microseconds\n" 770#endif 771#ifdef CONFIG_AUDIO_SDL 772 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 773 " in|out.buffer-count= number of buffers\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 spice,id=id[,prop[=value][,...]]`` 942 Creates a backend that sends audio through SPICE. This backend 943 requires ``-spice`` and automatically selected in that case, so 944 usually you can ignore this option. This backend has no backend 945 specific properties. 946 947``-audiodev wav,id=id[,prop[=value][,...]]`` 948 Creates a backend that writes audio to a WAV file. 949 950 Backend specific options are: 951 952 ``path=path`` 953 Write recorded audio into the specified file. Default is 954 ``qemu.wav``. 955ERST 956 957DEF("device", HAS_ARG, QEMU_OPTION_device, 958 "-device driver[,prop[=value][,...]]\n" 959 " add device (based on driver)\n" 960 " prop=value,... sets driver properties\n" 961 " use '-device help' to print all possible drivers\n" 962 " use '-device driver,help' to print all possible properties\n", 963 QEMU_ARCH_ALL) 964SRST 965``-device driver[,prop[=value][,...]]`` 966 Add device driver. prop=value sets driver properties. Valid 967 properties depend on the driver. To get help on possible drivers and 968 properties, use ``-device help`` and ``-device driver,help``. 969 970 Some drivers are: 971 972``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 973 Add an IPMI BMC. This is a simulation of a hardware management 974 interface processor that normally sits on a system. It provides a 975 watchdog and the ability to reset and power control the system. You 976 need to connect this to an IPMI interface to make it useful 977 978 The IPMI slave address to use for the BMC. The default is 0x20. This 979 address is the BMC's address on the I2C network of management 980 controllers. If you don't know what this means, it is safe to ignore 981 it. 982 983 ``id=id`` 984 The BMC id for interfaces to use this device. 985 986 ``slave_addr=val`` 987 Define slave address to use for the BMC. The default is 0x20. 988 989 ``sdrfile=file`` 990 file containing raw Sensor Data Records (SDR) data. The default 991 is none. 992 993 ``fruareasize=val`` 994 size of a Field Replaceable Unit (FRU) area. The default is 995 1024. 996 997 ``frudatafile=file`` 998 file containing raw Field Replaceable Unit (FRU) inventory data. 999 The default is none. 1000 1001 ``guid=uuid`` 1002 value for the GUID for the BMC, in standard UUID format. If this 1003 is set, get "Get GUID" command to the BMC will return it. 1004 Otherwise "Get GUID" will return an error. 1005 1006``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1007 Add a connection to an external IPMI BMC simulator. Instead of 1008 locally emulating the BMC like the above item, instead connect to an 1009 external entity that provides the IPMI services. 1010 1011 A connection is made to an external BMC simulator. If you do this, 1012 it is strongly recommended that you use the "reconnect=" chardev 1013 option to reconnect to the simulator if the connection is lost. Note 1014 that if this is not used carefully, it can be a security issue, as 1015 the interface has the ability to send resets, NMIs, and power off 1016 the VM. It's best if QEMU makes a connection to an external 1017 simulator running on a secure port on localhost, so neither the 1018 simulator nor QEMU is exposed to any outside network. 1019 1020 See the "lanserv/README.vm" file in the OpenIPMI library for more 1021 details on the external interface. 1022 1023``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1024 Add a KCS IPMI interafce on the ISA bus. This also adds a 1025 corresponding ACPI and SMBIOS entries, if appropriate. 1026 1027 ``bmc=id`` 1028 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1029 above. 1030 1031 ``ioport=val`` 1032 Define the I/O address of the interface. The default is 0xca0 1033 for KCS. 1034 1035 ``irq=val`` 1036 Define the interrupt to use. The default is 5. To disable 1037 interrupts, set this to 0. 1038 1039``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1040 Like the KCS interface, but defines a BT interface. The default port 1041 is 0xe4 and the default interrupt is 5. 1042 1043``-device pci-ipmi-kcs,bmc=id`` 1044 Add a KCS IPMI interafce on the PCI bus. 1045 1046 ``bmc=id`` 1047 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1048 1049``-device pci-ipmi-bt,bmc=id`` 1050 Like the KCS interface, but defines a BT interface on the PCI bus. 1051 1052``-device intel-iommu[,option=...]`` 1053 This is only supported by ``-machine q35``, which will enable Intel VT-d 1054 emulation within the guest. It supports below options: 1055 1056 ``intremap=on|off`` (default: auto) 1057 This enables interrupt remapping feature. It's required to enable 1058 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1059 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1060 The default value is "auto", which will be decided by the mode of 1061 kernel-irqchip. 1062 1063 ``caching-mode=on|off`` (default: off) 1064 This enables caching mode for the VT-d emulated device. When 1065 caching-mode is enabled, each guest DMA buffer mapping will generate an 1066 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1067 a synchronous way. It is required for ``-device vfio-pci`` to work 1068 with the VT-d device, because host assigned devices requires to setup 1069 the DMA mapping on the host before guest DMA starts. 1070 1071 ``device-iotlb=on|off`` (default: off) 1072 This enables device-iotlb capability for the emulated VT-d device. So 1073 far virtio/vhost should be the only real user for this parameter, 1074 paired with ats=on configured for the device. 1075 1076 ``aw-bits=39|48`` (default: 39) 1077 This decides the address width of IOVA address space. The address 1078 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1079 4-level IOMMU page tables. 1080 1081 Please also refer to the wiki page for general scenarios of VT-d 1082 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1083 1084ERST 1085 1086DEF("name", HAS_ARG, QEMU_OPTION_name, 1087 "-name string1[,process=string2][,debug-threads=on|off]\n" 1088 " set the name of the guest\n" 1089 " string1 sets the window title and string2 the process name\n" 1090 " When debug-threads is enabled, individual threads are given a separate name\n" 1091 " NOTE: The thread names are for debugging and not a stable API.\n", 1092 QEMU_ARCH_ALL) 1093SRST 1094``-name name`` 1095 Sets the name of the guest. This name will be displayed in the SDL 1096 window caption. The name will also be used for the VNC server. Also 1097 optionally set the top visible process name in Linux. Naming of 1098 individual threads can also be enabled on Linux to aid debugging. 1099ERST 1100 1101DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1102 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1103 " specify machine UUID\n", QEMU_ARCH_ALL) 1104SRST 1105``-uuid uuid`` 1106 Set system UUID. 1107ERST 1108 1109DEFHEADING() 1110 1111DEFHEADING(Block device options:) 1112 1113DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1114 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1115DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1116SRST 1117``-fda file`` 1118 \ 1119``-fdb file`` 1120 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1121 the System Emulation Users Guide). 1122ERST 1123 1124DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1125 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1126DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1127DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1128 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1129DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1130SRST 1131``-hda file`` 1132 \ 1133``-hdb file`` 1134 \ 1135``-hdc file`` 1136 \ 1137``-hdd file`` 1138 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1139 chapter in the System Emulation Users Guide). 1140ERST 1141 1142DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1143 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1144 QEMU_ARCH_ALL) 1145SRST 1146``-cdrom file`` 1147 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1148 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1149 as filename. 1150ERST 1151 1152DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1153 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1154 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1155 " [,read-only=on|off][,auto-read-only=on|off]\n" 1156 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1157 " [,driver specific parameters...]\n" 1158 " configure a block backend\n", QEMU_ARCH_ALL) 1159SRST 1160``-blockdev option[,option[,option[,...]]]`` 1161 Define a new block driver node. Some of the options apply to all 1162 block drivers, other options are only accepted for a specific block 1163 driver. See below for a list of generic options and options for the 1164 most common block drivers. 1165 1166 Options that expect a reference to another node (e.g. ``file``) can 1167 be given in two ways. Either you specify the node name of an already 1168 existing node (file=node-name), or you define a new node inline, 1169 adding options for the referenced node after a dot 1170 (file.filename=path,file.aio=native). 1171 1172 A block driver node created with ``-blockdev`` can be used for a 1173 guest device by specifying its node name for the ``drive`` property 1174 in a ``-device`` argument that defines a block device. 1175 1176 ``Valid options for any block driver node:`` 1177 ``driver`` 1178 Specifies the block driver to use for the given node. 1179 1180 ``node-name`` 1181 This defines the name of the block driver node by which it 1182 will be referenced later. The name must be unique, i.e. it 1183 must not match the name of a different block driver node, or 1184 (if you use ``-drive`` as well) the ID of a drive. 1185 1186 If no node name is specified, it is automatically generated. 1187 The generated node name is not intended to be predictable 1188 and changes between QEMU invocations. For the top level, an 1189 explicit node name must be specified. 1190 1191 ``read-only`` 1192 Open the node read-only. Guest write attempts will fail. 1193 1194 Note that some block drivers support only read-only access, 1195 either generally or in certain configurations. In this case, 1196 the default value ``read-only=off`` does not work and the 1197 option must be specified explicitly. 1198 1199 ``auto-read-only`` 1200 If ``auto-read-only=on`` is set, QEMU may fall back to 1201 read-only usage even when ``read-only=off`` is requested, or 1202 even switch between modes as needed, e.g. depending on 1203 whether the image file is writable or whether a writing user 1204 is attached to the node. 1205 1206 ``force-share`` 1207 Override the image locking system of QEMU by forcing the 1208 node to utilize weaker shared access for permissions where 1209 it would normally request exclusive access. When there is 1210 the potential for multiple instances to have the same file 1211 open (whether this invocation of QEMU is the first or the 1212 second instance), both instances must permit shared access 1213 for the second instance to succeed at opening the file. 1214 1215 Enabling ``force-share=on`` requires ``read-only=on``. 1216 1217 ``cache.direct`` 1218 The host page cache can be avoided with ``cache.direct=on``. 1219 This will attempt to do disk IO directly to the guest's 1220 memory. QEMU may still perform an internal copy of the data. 1221 1222 ``cache.no-flush`` 1223 In case you don't care about data integrity over host 1224 failures, you can use ``cache.no-flush=on``. This option 1225 tells QEMU that it never needs to write any data to the disk 1226 but can instead keep things in cache. If anything goes 1227 wrong, like your host losing power, the disk storage getting 1228 disconnected accidentally, etc. your image will most 1229 probably be rendered unusable. 1230 1231 ``discard=discard`` 1232 discard is one of "ignore" (or "off") or "unmap" (or "on") 1233 and controls whether ``discard`` (also known as ``trim`` or 1234 ``unmap``) requests are ignored or passed to the filesystem. 1235 Some machine types may not support discard requests. 1236 1237 ``detect-zeroes=detect-zeroes`` 1238 detect-zeroes is "off", "on" or "unmap" and enables the 1239 automatic conversion of plain zero writes by the OS to 1240 driver specific optimized zero write commands. You may even 1241 choose "unmap" if discard is set to "unmap" to allow a zero 1242 write to be converted to an ``unmap`` operation. 1243 1244 ``Driver-specific options for file`` 1245 This is the protocol-level block driver for accessing regular 1246 files. 1247 1248 ``filename`` 1249 The path to the image file in the local filesystem 1250 1251 ``aio`` 1252 Specifies the AIO backend (threads/native/io_uring, 1253 default: threads) 1254 1255 ``locking`` 1256 Specifies whether the image file is protected with Linux OFD 1257 / POSIX locks. The default is to use the Linux Open File 1258 Descriptor API if available, otherwise no lock is applied. 1259 (auto/on/off, default: auto) 1260 1261 Example: 1262 1263 :: 1264 1265 -blockdev driver=file,node-name=disk,filename=disk.img 1266 1267 ``Driver-specific options for raw`` 1268 This is the image format block driver for raw images. It is 1269 usually stacked on top of a protocol level block driver such as 1270 ``file``. 1271 1272 ``file`` 1273 Reference to or definition of the data source block driver 1274 node (e.g. a ``file`` driver node) 1275 1276 Example 1: 1277 1278 :: 1279 1280 -blockdev driver=file,node-name=disk_file,filename=disk.img 1281 -blockdev driver=raw,node-name=disk,file=disk_file 1282 1283 Example 2: 1284 1285 :: 1286 1287 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1288 1289 ``Driver-specific options for qcow2`` 1290 This is the image format block driver for qcow2 images. It is 1291 usually stacked on top of a protocol level block driver such as 1292 ``file``. 1293 1294 ``file`` 1295 Reference to or definition of the data source block driver 1296 node (e.g. a ``file`` driver node) 1297 1298 ``backing`` 1299 Reference to or definition of the backing file block device 1300 (default is taken from the image file). It is allowed to 1301 pass ``null`` here in order to disable the default backing 1302 file. 1303 1304 ``lazy-refcounts`` 1305 Whether to enable the lazy refcounts feature (on/off; 1306 default is taken from the image file) 1307 1308 ``cache-size`` 1309 The maximum total size of the L2 table and refcount block 1310 caches in bytes (default: the sum of l2-cache-size and 1311 refcount-cache-size) 1312 1313 ``l2-cache-size`` 1314 The maximum size of the L2 table cache in bytes (default: if 1315 cache-size is not specified - 32M on Linux platforms, and 8M 1316 on non-Linux platforms; otherwise, as large as possible 1317 within the cache-size, while permitting the requested or the 1318 minimal refcount cache size) 1319 1320 ``refcount-cache-size`` 1321 The maximum size of the refcount block cache in bytes 1322 (default: 4 times the cluster size; or if cache-size is 1323 specified, the part of it which is not used for the L2 1324 cache) 1325 1326 ``cache-clean-interval`` 1327 Clean unused entries in the L2 and refcount caches. The 1328 interval is in seconds. The default value is 600 on 1329 supporting platforms, and 0 on other platforms. Setting it 1330 to 0 disables this feature. 1331 1332 ``pass-discard-request`` 1333 Whether discard requests to the qcow2 device should be 1334 forwarded to the data source (on/off; default: on if 1335 discard=unmap is specified, off otherwise) 1336 1337 ``pass-discard-snapshot`` 1338 Whether discard requests for the data source should be 1339 issued when a snapshot operation (e.g. deleting a snapshot) 1340 frees clusters in the qcow2 file (on/off; default: on) 1341 1342 ``pass-discard-other`` 1343 Whether discard requests for the data source should be 1344 issued on other occasions where a cluster gets freed 1345 (on/off; default: off) 1346 1347 ``overlap-check`` 1348 Which overlap checks to perform for writes to the image 1349 (none/constant/cached/all; default: cached). For details or 1350 finer granularity control refer to the QAPI documentation of 1351 ``blockdev-add``. 1352 1353 Example 1: 1354 1355 :: 1356 1357 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1358 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1359 1360 Example 2: 1361 1362 :: 1363 1364 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1365 1366 ``Driver-specific options for other drivers`` 1367 Please refer to the QAPI documentation of the ``blockdev-add`` 1368 QMP command. 1369ERST 1370 1371DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1372 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1373 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1374 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1375 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1376 " [,aio=threads|native|io_uring]\n" 1377 " [,readonly=on|off][,copy-on-read=on|off]\n" 1378 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1379 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1380 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1381 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1382 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1383 " [[,iops_size=is]]\n" 1384 " [[,group=g]]\n" 1385 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1386SRST 1387``-drive option[,option[,option[,...]]]`` 1388 Define a new drive. This includes creating a block driver node (the 1389 backend) as well as a guest device, and is mostly a shortcut for 1390 defining the corresponding ``-blockdev`` and ``-device`` options. 1391 1392 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1393 In addition, it knows the following options: 1394 1395 ``file=file`` 1396 This option defines which disk image (see the :ref:`disk images` 1397 chapter in the System Emulation Users Guide) to use with this drive. 1398 If the filename contains comma, you must double it (for instance, 1399 "file=my,,file" to use file "my,file"). 1400 1401 Special files such as iSCSI devices can be specified using 1402 protocol specific URLs. See the section for "Device URL Syntax" 1403 for more information. 1404 1405 ``if=interface`` 1406 This option defines on which type on interface the drive is 1407 connected. Available types are: ide, scsi, sd, mtd, floppy, 1408 pflash, virtio, none. 1409 1410 ``bus=bus,unit=unit`` 1411 These options define where is connected the drive by defining 1412 the bus number and the unit id. 1413 1414 ``index=index`` 1415 This option defines where the drive is connected by using an 1416 index in the list of available connectors of a given interface 1417 type. 1418 1419 ``media=media`` 1420 This option defines the type of the media: disk or cdrom. 1421 1422 ``snapshot=snapshot`` 1423 snapshot is "on" or "off" and controls snapshot mode for the 1424 given drive (see ``-snapshot``). 1425 1426 ``cache=cache`` 1427 cache is "none", "writeback", "unsafe", "directsync" or 1428 "writethrough" and controls how the host cache is used to access 1429 block data. This is a shortcut that sets the ``cache.direct`` 1430 and ``cache.no-flush`` options (as in ``-blockdev``), and 1431 additionally ``cache.writeback``, which provides a default for 1432 the ``write-cache`` option of block guest devices (as in 1433 ``-device``). The modes correspond to the following settings: 1434 1435 ============= =============== ============ ============== 1436 \ cache.writeback cache.direct cache.no-flush 1437 ============= =============== ============ ============== 1438 writeback on off off 1439 none on on off 1440 writethrough off off off 1441 directsync off on off 1442 unsafe on off on 1443 ============= =============== ============ ============== 1444 1445 The default mode is ``cache=writeback``. 1446 1447 ``aio=aio`` 1448 aio is "threads", "native", or "io_uring" and selects between pthread 1449 based disk I/O, native Linux AIO, or Linux io_uring API. 1450 1451 ``format=format`` 1452 Specify which disk format will be used rather than detecting the 1453 format. Can be used to specify format=raw to avoid interpreting 1454 an untrusted format header. 1455 1456 ``werror=action,rerror=action`` 1457 Specify which action to take on write and read errors. Valid 1458 actions are: "ignore" (ignore the error and try to continue), 1459 "stop" (pause QEMU), "report" (report the error to the guest), 1460 "enospc" (pause QEMU only if the host disk is full; report the 1461 error to the guest otherwise). The default setting is 1462 ``werror=enospc`` and ``rerror=report``. 1463 1464 ``copy-on-read=copy-on-read`` 1465 copy-on-read is "on" or "off" and enables whether to copy read 1466 backing file sectors into the image file. 1467 1468 ``bps=b,bps_rd=r,bps_wr=w`` 1469 Specify bandwidth throttling limits in bytes per second, either 1470 for all request types or for reads or writes only. Small values 1471 can lead to timeouts or hangs inside the guest. A safe minimum 1472 for disks is 2 MB/s. 1473 1474 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1475 Specify bursts in bytes per second, either for all request types 1476 or for reads or writes only. Bursts allow the guest I/O to spike 1477 above the limit temporarily. 1478 1479 ``iops=i,iops_rd=r,iops_wr=w`` 1480 Specify request rate limits in requests per second, either for 1481 all request types or for reads or writes only. 1482 1483 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1484 Specify bursts in requests per second, either for all request 1485 types or for reads or writes only. Bursts allow the guest I/O to 1486 spike above the limit temporarily. 1487 1488 ``iops_size=is`` 1489 Let every is bytes of a request count as a new request for iops 1490 throttling purposes. Use this option to prevent guests from 1491 circumventing iops limits by sending fewer but larger requests. 1492 1493 ``group=g`` 1494 Join a throttling quota group with given name g. All drives that 1495 are members of the same group are accounted for together. Use 1496 this option to prevent guests from circumventing throttling 1497 limits by using many small disks instead of a single larger 1498 disk. 1499 1500 By default, the ``cache.writeback=on`` mode is used. It will report 1501 data writes as completed as soon as the data is present in the host 1502 page cache. This is safe as long as your guest OS makes sure to 1503 correctly flush disk caches where needed. If your guest OS does not 1504 handle volatile disk write caches correctly and your host crashes or 1505 loses power, then the guest may experience data corruption. 1506 1507 For such guests, you should consider using ``cache.writeback=off``. 1508 This means that the host page cache will be used to read and write 1509 data, but write notification will be sent to the guest only after 1510 QEMU has made sure to flush each write to the disk. Be aware that 1511 this has a major impact on performance. 1512 1513 When using the ``-snapshot`` option, unsafe caching is always used. 1514 1515 Copy-on-read avoids accessing the same backing file sectors 1516 repeatedly and is useful when the backing file is over a slow 1517 network. By default copy-on-read is off. 1518 1519 Instead of ``-cdrom`` you can use: 1520 1521 .. parsed-literal:: 1522 1523 |qemu_system| -drive file=file,index=2,media=cdrom 1524 1525 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1526 1527 .. parsed-literal:: 1528 1529 |qemu_system| -drive file=file,index=0,media=disk 1530 |qemu_system| -drive file=file,index=1,media=disk 1531 |qemu_system| -drive file=file,index=2,media=disk 1532 |qemu_system| -drive file=file,index=3,media=disk 1533 1534 You can open an image using pre-opened file descriptors from an fd 1535 set: 1536 1537 .. parsed-literal:: 1538 1539 |qemu_system| \\ 1540 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1541 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1542 -drive file=/dev/fdset/2,index=0,media=disk 1543 1544 You can connect a CDROM to the slave of ide0: 1545 1546 .. parsed-literal:: 1547 1548 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1549 1550 If you don't specify the "file=" argument, you define an empty 1551 drive: 1552 1553 .. parsed-literal:: 1554 1555 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1556 1557 Instead of ``-fda``, ``-fdb``, you can use: 1558 1559 .. parsed-literal:: 1560 1561 |qemu_system_x86| -drive file=file,index=0,if=floppy 1562 |qemu_system_x86| -drive file=file,index=1,if=floppy 1563 1564 By default, interface is "ide" and index is automatically 1565 incremented: 1566 1567 .. parsed-literal:: 1568 1569 |qemu_system_x86| -drive file=a -drive file=b" 1570 1571 is interpreted like: 1572 1573 .. parsed-literal:: 1574 1575 |qemu_system_x86| -hda a -hdb b 1576ERST 1577 1578DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1579 "-mtdblock file use 'file' as on-board Flash memory image\n", 1580 QEMU_ARCH_ALL) 1581SRST 1582``-mtdblock file`` 1583 Use file as on-board Flash memory image. 1584ERST 1585 1586DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1587 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1588SRST 1589``-sd file`` 1590 Use file as SecureDigital card image. 1591ERST 1592 1593DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1594 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1595SRST 1596``-pflash file`` 1597 Use file as a parallel flash image. 1598ERST 1599 1600DEF("snapshot", 0, QEMU_OPTION_snapshot, 1601 "-snapshot write to temporary files instead of disk image files\n", 1602 QEMU_ARCH_ALL) 1603SRST 1604``-snapshot`` 1605 Write to temporary files instead of disk image files. In this case, 1606 the raw disk image you use is not written back. You can however 1607 force the write back by pressing C-a s (see the :ref:`disk images` 1608 chapter in the System Emulation Users Guide). 1609ERST 1610 1611DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1612 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1613 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1614 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1615 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1616 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1617 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1618 " [[,throttling.iops-size=is]]\n" 1619 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1620 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1621 "-fsdev synth,id=id\n", 1622 QEMU_ARCH_ALL) 1623 1624SRST 1625``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1626 \ 1627``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1628 \ 1629``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1630 \ 1631``-fsdev synth,id=id[,readonly=on]`` 1632 Define a new file system device. Valid options are: 1633 1634 ``local`` 1635 Accesses to the filesystem are done by QEMU. 1636 1637 ``proxy`` 1638 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1639 1640 ``synth`` 1641 Synthetic filesystem, only used by QTests. 1642 1643 ``id=id`` 1644 Specifies identifier for this device. 1645 1646 ``path=path`` 1647 Specifies the export path for the file system device. Files 1648 under this path will be available to the 9p client on the guest. 1649 1650 ``security_model=security_model`` 1651 Specifies the security model to be used for this export path. 1652 Supported security models are "passthrough", "mapped-xattr", 1653 "mapped-file" and "none". In "passthrough" security model, files 1654 are stored using the same credentials as they are created on the 1655 guest. This requires QEMU to run as root. In "mapped-xattr" 1656 security model, some of the file attributes like uid, gid, mode 1657 bits and link target are stored as file attributes. For 1658 "mapped-file" these attributes are stored in the hidden 1659 .virtfs\_metadata directory. Directories exported by this 1660 security model cannot interact with other unix tools. "none" 1661 security model is same as passthrough except the sever won't 1662 report failures if it fails to set file attributes like 1663 ownership. Security model is mandatory only for local fsdriver. 1664 Other fsdrivers (like proxy) don't take security model as a 1665 parameter. 1666 1667 ``writeout=writeout`` 1668 This is an optional argument. The only supported value is 1669 "immediate". This means that host page cache will be used to 1670 read and write data but write notification will be sent to the 1671 guest only when the data has been reported as written by the 1672 storage subsystem. 1673 1674 ``readonly=on`` 1675 Enables exporting 9p share as a readonly mount for guests. By 1676 default read-write access is given. 1677 1678 ``socket=socket`` 1679 Enables proxy filesystem driver to use passed socket file for 1680 communicating with virtfs-proxy-helper(1). 1681 1682 ``sock_fd=sock_fd`` 1683 Enables proxy filesystem driver to use passed socket descriptor 1684 for communicating with virtfs-proxy-helper(1). Usually a helper 1685 like libvirt will create socketpair and pass one of the fds as 1686 sock\_fd. 1687 1688 ``fmode=fmode`` 1689 Specifies the default mode for newly created files on the host. 1690 Works only with security models "mapped-xattr" and 1691 "mapped-file". 1692 1693 ``dmode=dmode`` 1694 Specifies the default mode for newly created directories on the 1695 host. Works only with security models "mapped-xattr" and 1696 "mapped-file". 1697 1698 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1699 Specify bandwidth throttling limits in bytes per second, either 1700 for all request types or for reads or writes only. 1701 1702 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1703 Specify bursts in bytes per second, either for all request types 1704 or for reads or writes only. Bursts allow the guest I/O to spike 1705 above the limit temporarily. 1706 1707 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1708 Specify request rate limits in requests per second, either for 1709 all request types or for reads or writes only. 1710 1711 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1712 Specify bursts in requests per second, either for all request 1713 types or for reads or writes only. Bursts allow the guest I/O to 1714 spike above the limit temporarily. 1715 1716 ``throttling.iops-size=is`` 1717 Let every is bytes of a request count as a new request for iops 1718 throttling purposes. 1719 1720 -fsdev option is used along with -device driver "virtio-9p-...". 1721 1722``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1723 Options for virtio-9p-... driver are: 1724 1725 ``type`` 1726 Specifies the variant to be used. Supported values are "pci", 1727 "ccw" or "device", depending on the machine type. 1728 1729 ``fsdev=id`` 1730 Specifies the id value specified along with -fsdev option. 1731 1732 ``mount_tag=mount_tag`` 1733 Specifies the tag name to be used by the guest to mount this 1734 export point. 1735ERST 1736 1737DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1738 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1739 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1740 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1741 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1742 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1743 QEMU_ARCH_ALL) 1744 1745SRST 1746``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1747 \ 1748``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1749 \ 1750``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1751 \ 1752``-virtfs synth,mount_tag=mount_tag`` 1753 Define a new virtual filesystem device and expose it to the guest using 1754 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1755 directory on host is made directly accessible by guest as a pass-through 1756 file system by using the 9P network protocol for communication between 1757 host and guests, if desired even accessible, shared by several guests 1758 simultaniously. 1759 1760 Note that ``-virtfs`` is actually just a convenience shortcut for its 1761 generalized form ``-fsdev -device virtio-9p-pci``. 1762 1763 The general form of pass-through file system options are: 1764 1765 ``local`` 1766 Accesses to the filesystem are done by QEMU. 1767 1768 ``proxy`` 1769 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1770 1771 ``synth`` 1772 Synthetic filesystem, only used by QTests. 1773 1774 ``id=id`` 1775 Specifies identifier for the filesystem device 1776 1777 ``path=path`` 1778 Specifies the export path for the file system device. Files 1779 under this path will be available to the 9p client on the guest. 1780 1781 ``security_model=security_model`` 1782 Specifies the security model to be used for this export path. 1783 Supported security models are "passthrough", "mapped-xattr", 1784 "mapped-file" and "none". In "passthrough" security model, files 1785 are stored using the same credentials as they are created on the 1786 guest. This requires QEMU to run as root. In "mapped-xattr" 1787 security model, some of the file attributes like uid, gid, mode 1788 bits and link target are stored as file attributes. For 1789 "mapped-file" these attributes are stored in the hidden 1790 .virtfs\_metadata directory. Directories exported by this 1791 security model cannot interact with other unix tools. "none" 1792 security model is same as passthrough except the sever won't 1793 report failures if it fails to set file attributes like 1794 ownership. Security model is mandatory only for local fsdriver. 1795 Other fsdrivers (like proxy) don't take security model as a 1796 parameter. 1797 1798 ``writeout=writeout`` 1799 This is an optional argument. The only supported value is 1800 "immediate". This means that host page cache will be used to 1801 read and write data but write notification will be sent to the 1802 guest only when the data has been reported as written by the 1803 storage subsystem. 1804 1805 ``readonly=on`` 1806 Enables exporting 9p share as a readonly mount for guests. By 1807 default read-write access is given. 1808 1809 ``socket=socket`` 1810 Enables proxy filesystem driver to use passed socket file for 1811 communicating with virtfs-proxy-helper(1). Usually a helper like 1812 libvirt will create socketpair and pass one of the fds as 1813 sock\_fd. 1814 1815 ``sock_fd`` 1816 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1817 socket descriptor for interfacing with virtfs-proxy-helper(1). 1818 1819 ``fmode=fmode`` 1820 Specifies the default mode for newly created files on the host. 1821 Works only with security models "mapped-xattr" and 1822 "mapped-file". 1823 1824 ``dmode=dmode`` 1825 Specifies the default mode for newly created directories on the 1826 host. Works only with security models "mapped-xattr" and 1827 "mapped-file". 1828 1829 ``mount_tag=mount_tag`` 1830 Specifies the tag name to be used by the guest to mount this 1831 export point. 1832 1833 ``multidevs=multidevs`` 1834 Specifies how to deal with multiple devices being shared with a 1835 9p export. Supported behaviours are either "remap", "forbid" or 1836 "warn". The latter is the default behaviour on which virtfs 9p 1837 expects only one device to be shared with the same export, and 1838 if more than one device is shared and accessed via the same 9p 1839 export then only a warning message is logged (once) by qemu on 1840 host side. In order to avoid file ID collisions on guest you 1841 should either create a separate virtfs export for each device to 1842 be shared with guests (recommended way) or you might use "remap" 1843 instead which allows you to share multiple devices with only one 1844 export instead, which is achieved by remapping the original 1845 inode numbers from host to guest in a way that would prevent 1846 such collisions. Remapping inodes in such use cases is required 1847 because the original device IDs from host are never passed and 1848 exposed on guest. Instead all files of an export shared with 1849 virtfs always share the same device id on guest. So two files 1850 with identical inode numbers but from actually different devices 1851 on host would otherwise cause a file ID collision and hence 1852 potential misbehaviours on guest. "forbid" on the other hand 1853 assumes like "warn" that only one device is shared by the same 1854 export, however it will not only log a warning message but also 1855 deny access to additional devices on guest. Note though that 1856 "forbid" does currently not block all possible file access 1857 operations (e.g. readdir() would still return entries from other 1858 devices). 1859ERST 1860 1861DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1862 "-iscsi [user=user][,password=password]\n" 1863 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1864 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1865 " [,timeout=timeout]\n" 1866 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1867 1868SRST 1869``-iscsi`` 1870 Configure iSCSI session parameters. 1871ERST 1872 1873DEFHEADING() 1874 1875DEFHEADING(USB convenience options:) 1876 1877DEF("usb", 0, QEMU_OPTION_usb, 1878 "-usb enable on-board USB host controller (if not enabled by default)\n", 1879 QEMU_ARCH_ALL) 1880SRST 1881``-usb`` 1882 Enable USB emulation on machine types with an on-board USB host 1883 controller (if not enabled by default). Note that on-board USB host 1884 controllers may not support USB 3.0. In this case 1885 ``-device qemu-xhci`` can be used instead on machines with PCI. 1886ERST 1887 1888DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1889 "-usbdevice name add the host or guest USB device 'name'\n", 1890 QEMU_ARCH_ALL) 1891SRST 1892``-usbdevice devname`` 1893 Add the USB device devname, and enable an on-board USB controller 1894 if possible and necessary (just like it can be done via 1895 ``-machine usb=on``). Note that this option is mainly intended for 1896 the user's convenience only. More fine-grained control can be 1897 achieved by selecting a USB host controller (if necessary) and the 1898 desired USB device via the ``-device`` option instead. For example, 1899 instead of using ``-usbdevice mouse`` it is possible to use 1900 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1901 to a USB 3.0 controller instead (at least on machines that support 1902 PCI and do not have an USB controller enabled by default yet). 1903 For more details, see the chapter about 1904 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1905 Possible devices for devname are: 1906 1907 ``braille`` 1908 Braille device. This will use BrlAPI to display the braille 1909 output on a real or fake device (i.e. it also creates a 1910 corresponding ``braille`` chardev automatically beside the 1911 ``usb-braille`` USB device). 1912 1913 ``keyboard`` 1914 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1915 1916 ``mouse`` 1917 Virtual Mouse. This will override the PS/2 mouse emulation when 1918 activated. 1919 1920 ``tablet`` 1921 Pointer device that uses absolute coordinates (like a 1922 touchscreen). This means QEMU is able to report the mouse 1923 position without having to grab the mouse. Also overrides the 1924 PS/2 mouse emulation when activated. 1925 1926 ``wacom-tablet`` 1927 Wacom PenPartner USB tablet. 1928 1929 1930ERST 1931 1932DEFHEADING() 1933 1934DEFHEADING(Display options:) 1935 1936DEF("display", HAS_ARG, QEMU_OPTION_display, 1937#if defined(CONFIG_SPICE) 1938 "-display spice-app[,gl=on|off]\n" 1939#endif 1940#if defined(CONFIG_SDL) 1941 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1942 " [,grab-mod=<mod>][,show-cursor=on|off][,window-close=on|off]\n" 1943#endif 1944#if defined(CONFIG_GTK) 1945 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1946 " [,show-cursor=on|off][,window-close=on|off]\n" 1947#endif 1948#if defined(CONFIG_VNC) 1949 "-display vnc=<display>[,<optargs>]\n" 1950#endif 1951#if defined(CONFIG_CURSES) 1952 "-display curses[,charset=<encoding>]\n" 1953#endif 1954#if defined(CONFIG_COCOA) 1955 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 1956#endif 1957#if defined(CONFIG_OPENGL) 1958 "-display egl-headless[,rendernode=<file>]\n" 1959#endif 1960#if defined(CONFIG_DBUS_DISPLAY) 1961 "-display dbus[,addr=<dbusaddr>]\n" 1962 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1963#endif 1964#if defined(CONFIG_COCOA) 1965 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 1966#endif 1967 "-display none\n" 1968 " select display backend type\n" 1969 " The default display is equivalent to\n " 1970#if defined(CONFIG_GTK) 1971 "\"-display gtk\"\n" 1972#elif defined(CONFIG_SDL) 1973 "\"-display sdl\"\n" 1974#elif defined(CONFIG_COCOA) 1975 "\"-display cocoa\"\n" 1976#elif defined(CONFIG_VNC) 1977 "\"-vnc localhost:0,to=99,id=default\"\n" 1978#else 1979 "\"-display none\"\n" 1980#endif 1981 , QEMU_ARCH_ALL) 1982SRST 1983``-display type`` 1984 Select type of display to use. This option is a replacement for the 1985 old style -sdl/-curses/... options. Use ``-display help`` to list 1986 the available display types. Valid values for type are 1987 1988 ``spice-app[,gl=on|off]`` 1989 Start QEMU as a Spice server and launch the default Spice client 1990 application. The Spice server will redirect the serial consoles 1991 and QEMU monitors. (Since 4.0) 1992 1993 ``dbus`` 1994 Export the display over D-Bus interfaces. (Since 7.0) 1995 1996 The connection is registered with the "org.qemu" name (and queued when 1997 already owned). 1998 1999 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2000 2001 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2002 2003 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2004 will share framebuffers with DMABUF file descriptors). 2005 2006 ``sdl`` 2007 Display video output via SDL (usually in a separate graphics 2008 window; see the SDL documentation for other possibilities). 2009 Valid parameters are: 2010 2011 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2012 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2013 either ``lshift-lctrl-lalt`` or ``rctrl``. 2014 2015 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing. 2016 This parameter is deprecated - use ``grab-mod`` instead. 2017 2018 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing. 2019 This parameter is deprecated - use ``grab-mod`` instead. 2020 2021 ``gl=on|off|core|es`` : Use OpenGL for displaying 2022 2023 ``show-cursor=on|off`` : Force showing the mouse cursor 2024 2025 ``window-close=on|off`` : Allow to quit qemu with window close button 2026 2027 ``gtk`` 2028 Display video output in a GTK window. This interface provides 2029 drop-down menus and other UI elements to configure and control 2030 the VM during runtime. Valid parameters are: 2031 2032 ``full-screen=on|off`` : Start in fullscreen mode 2033 2034 ``gl=on|off`` : Use OpenGL for displaying 2035 2036 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2037 2038 ``show-cursor=on|off`` : Force showing the mouse cursor 2039 2040 ``window-close=on|off`` : Allow to quit qemu with window close button 2041 2042 ``curses[,charset=<encoding>]`` 2043 Display video output via curses. For graphics device models 2044 which support a text mode, QEMU can display this output using a 2045 curses/ncurses interface. Nothing is displayed when the graphics 2046 device is in graphical mode or if the graphics device does not 2047 support a text mode. Generally only the VGA device models 2048 support text mode. The font charset used by the guest can be 2049 specified with the ``charset`` option, for example 2050 ``charset=CP850`` for IBM CP850 encoding. The default is 2051 ``CP437``. 2052 2053 ``cocoa`` 2054 Display video output in a Cocoa window. Mac only. This interface 2055 provides drop-down menus and other UI elements to configure and 2056 control the VM during runtime. Valid parameters are: 2057 2058 ``show-cursor=on|off`` : Force showing the mouse cursor 2059 2060 ``left-command-key=on|off`` : Disable forwarding left command key to host 2061 2062 ``egl-headless[,rendernode=<file>]`` 2063 Offload all OpenGL operations to a local DRI device. For any 2064 graphical display, this display needs to be paired with either 2065 VNC or SPICE displays. 2066 2067 ``vnc=<display>`` 2068 Start a VNC server on display <display> 2069 2070 ``none`` 2071 Do not display video output. The guest will still see an 2072 emulated graphics card, but its output will not be displayed to 2073 the QEMU user. This option differs from the -nographic option in 2074 that it only affects what is done with video output; -nographic 2075 also changes the destination of the serial and parallel port 2076 data. 2077ERST 2078 2079DEF("nographic", 0, QEMU_OPTION_nographic, 2080 "-nographic disable graphical output and redirect serial I/Os to console\n", 2081 QEMU_ARCH_ALL) 2082SRST 2083``-nographic`` 2084 Normally, if QEMU is compiled with graphical window support, it 2085 displays output such as guest graphics, guest console, and the QEMU 2086 monitor in a window. With this option, you can totally disable 2087 graphical output so that QEMU is a simple command line application. 2088 The emulated serial port is redirected on the console and muxed with 2089 the monitor (unless redirected elsewhere explicitly). Therefore, you 2090 can still use QEMU to debug a Linux kernel with a serial console. 2091 Use C-a h for help on switching between the console and monitor. 2092ERST 2093 2094DEF("curses", 0, QEMU_OPTION_curses, 2095 "-curses shorthand for -display curses\n", 2096 QEMU_ARCH_ALL) 2097SRST 2098``-curses`` 2099 Normally, if QEMU is compiled with graphical window support, it 2100 displays output such as guest graphics, guest console, and the QEMU 2101 monitor in a window. With this option, QEMU can display the VGA 2102 output when in text mode using a curses/ncurses interface. Nothing 2103 is displayed in graphical mode. 2104ERST 2105 2106DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 2107 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 2108 QEMU_ARCH_ALL) 2109SRST 2110``-alt-grab`` 2111 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 2112 this also affects the special keys (for fullscreen, monitor-mode 2113 switching, etc). This option is deprecated - please use 2114 ``-display sdl,grab-mod=lshift-lctrl-lalt`` instead. 2115ERST 2116 2117DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 2118 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 2119 QEMU_ARCH_ALL) 2120SRST 2121``-ctrl-grab`` 2122 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 2123 also affects the special keys (for fullscreen, monitor-mode 2124 switching, etc). This option is deprecated - please use 2125 ``-display sdl,grab-mod=rctrl`` instead. 2126ERST 2127 2128DEF("sdl", 0, QEMU_OPTION_sdl, 2129 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 2130SRST 2131``-sdl`` 2132 Enable SDL. 2133ERST 2134 2135#ifdef CONFIG_SPICE 2136DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2137 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2138 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2139 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2140 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2141 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2142 " [,tls-ciphers=<list>]\n" 2143 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2144 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2145 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2146 " [,password=<string>][,password-secret=<secret-id>]\n" 2147 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2148 " [,jpeg-wan-compression=[auto|never|always]]\n" 2149 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2150 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2151 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2152 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2153 " [,gl=[on|off]][,rendernode=<file>]\n" 2154 " enable spice\n" 2155 " at least one of {port, tls-port} is mandatory\n", 2156 QEMU_ARCH_ALL) 2157#endif 2158SRST 2159``-spice option[,option[,...]]`` 2160 Enable the spice remote desktop protocol. Valid options are 2161 2162 ``port=<nr>`` 2163 Set the TCP port spice is listening on for plaintext channels. 2164 2165 ``addr=<addr>`` 2166 Set the IP address spice is listening on. Default is any 2167 address. 2168 2169 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2170 Force using the specified IP version. 2171 2172 ``password=<string>`` 2173 Set the password you need to authenticate. 2174 2175 This option is deprecated and insecure because it leaves the 2176 password visible in the process listing. Use ``password-secret`` 2177 instead. 2178 2179 ``password-secret=<secret-id>`` 2180 Set the ID of the ``secret`` object containing the password 2181 you need to authenticate. 2182 2183 ``sasl=on|off`` 2184 Require that the client use SASL to authenticate with the spice. 2185 The exact choice of authentication method used is controlled 2186 from the system / user's SASL configuration file for the 'qemu' 2187 service. This is typically found in /etc/sasl2/qemu.conf. If 2188 running QEMU as an unprivileged user, an environment variable 2189 SASL\_CONF\_PATH can be used to make it search alternate 2190 locations for the service config. While some SASL auth methods 2191 can also provide data encryption (eg GSSAPI), it is recommended 2192 that SASL always be combined with the 'tls' and 'x509' settings 2193 to enable use of SSL and server certificates. This ensures a 2194 data encryption preventing compromise of authentication 2195 credentials. 2196 2197 ``disable-ticketing=on|off`` 2198 Allow client connects without authentication. 2199 2200 ``disable-copy-paste=on|off`` 2201 Disable copy paste between the client and the guest. 2202 2203 ``disable-agent-file-xfer=on|off`` 2204 Disable spice-vdagent based file-xfer between the client and the 2205 guest. 2206 2207 ``tls-port=<nr>`` 2208 Set the TCP port spice is listening on for encrypted channels. 2209 2210 ``x509-dir=<dir>`` 2211 Set the x509 file directory. Expects same filenames as -vnc 2212 $display,x509=$dir 2213 2214 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2215 The x509 file names can also be configured individually. 2216 2217 ``tls-ciphers=<list>`` 2218 Specify which ciphers to use. 2219 2220 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2221 Force specific channel to be used with or without TLS 2222 encryption. The options can be specified multiple times to 2223 configure multiple channels. The special name "default" can be 2224 used to set the default mode. For channels which are not 2225 explicitly forced into one mode the spice client is allowed to 2226 pick tls/plaintext as he pleases. 2227 2228 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2229 Configure image compression (lossless). Default is auto\_glz. 2230 2231 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2232 Configure wan image compression (lossy for slow links). Default 2233 is auto. 2234 2235 ``streaming-video=[off|all|filter]`` 2236 Configure video stream detection. Default is off. 2237 2238 ``agent-mouse=[on|off]`` 2239 Enable/disable passing mouse events via vdagent. Default is on. 2240 2241 ``playback-compression=[on|off]`` 2242 Enable/disable audio stream compression (using celt 0.5.1). 2243 Default is on. 2244 2245 ``seamless-migration=[on|off]`` 2246 Enable/disable spice seamless migration. Default is off. 2247 2248 ``gl=[on|off]`` 2249 Enable/disable OpenGL context. Default is off. 2250 2251 ``rendernode=<file>`` 2252 DRM render node for OpenGL rendering. If not specified, it will 2253 pick the first available. (Since 2.9) 2254ERST 2255 2256DEF("portrait", 0, QEMU_OPTION_portrait, 2257 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2258 QEMU_ARCH_ALL) 2259SRST 2260``-portrait`` 2261 Rotate graphical output 90 deg left (only PXA LCD). 2262ERST 2263 2264DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2265 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2266 QEMU_ARCH_ALL) 2267SRST 2268``-rotate deg`` 2269 Rotate graphical output some deg left (only PXA LCD). 2270ERST 2271 2272DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2273 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2274 " select video card type\n", QEMU_ARCH_ALL) 2275SRST 2276``-vga type`` 2277 Select type of VGA card to emulate. Valid values for type are 2278 2279 ``cirrus`` 2280 Cirrus Logic GD5446 Video card. All Windows versions starting 2281 from Windows 95 should recognize and use this graphic card. For 2282 optimal performances, use 16 bit color depth in the guest and 2283 the host OS. (This card was the default before QEMU 2.2) 2284 2285 ``std`` 2286 Standard VGA card with Bochs VBE extensions. If your guest OS 2287 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2288 you want to use high resolution modes (>= 1280x1024x16) then you 2289 should use this option. (This card is the default since QEMU 2290 2.2) 2291 2292 ``vmware`` 2293 VMWare SVGA-II compatible adapter. Use it if you have 2294 sufficiently recent XFree86/XOrg server or Windows guest with a 2295 driver for this card. 2296 2297 ``qxl`` 2298 QXL paravirtual graphic card. It is VGA compatible (including 2299 VESA 2.0 VBE support). Works best with qxl guest drivers 2300 installed though. Recommended choice when using the spice 2301 protocol. 2302 2303 ``tcx`` 2304 (sun4m only) Sun TCX framebuffer. This is the default 2305 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2306 colour depths at a fixed resolution of 1024x768. 2307 2308 ``cg3`` 2309 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2310 framebuffer for sun4m machines available in both 1024x768 2311 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2312 wishing to run older Solaris versions. 2313 2314 ``virtio`` 2315 Virtio VGA card. 2316 2317 ``none`` 2318 Disable VGA card. 2319ERST 2320 2321DEF("full-screen", 0, QEMU_OPTION_full_screen, 2322 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2323SRST 2324``-full-screen`` 2325 Start in full screen. 2326ERST 2327 2328DEF("g", HAS_ARG, QEMU_OPTION_g , 2329 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2330 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2331SRST 2332``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2333 Set the initial graphical resolution and depth (PPC, SPARC only). 2334 2335 For PPC the default is 800x600x32. 2336 2337 For SPARC with the TCX graphics device, the default is 1024x768x8 2338 with the option of 1024x768x24. For cgthree, the default is 2339 1024x768x8 with the option of 1152x900x8 for people who wish to use 2340 OBP. 2341ERST 2342 2343DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2344 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2345SRST 2346``-vnc display[,option[,option[,...]]]`` 2347 Normally, if QEMU is compiled with graphical window support, it 2348 displays output such as guest graphics, guest console, and the QEMU 2349 monitor in a window. With this option, you can have QEMU listen on 2350 VNC display display and redirect the VGA display over the VNC 2351 session. It is very useful to enable the usb tablet device when 2352 using this option (option ``-device usb-tablet``). When using the 2353 VNC display, you must use the ``-k`` parameter to set the keyboard 2354 layout if you are not using en-us. Valid syntax for the display is 2355 2356 ``to=L`` 2357 With this option, QEMU will try next available VNC displays, 2358 until the number L, if the origianlly defined "-vnc display" is 2359 not available, e.g. port 5900+display is already used by another 2360 application. By default, to=0. 2361 2362 ``host:d`` 2363 TCP connections will only be allowed from host on display d. By 2364 convention the TCP port is 5900+d. Optionally, host can be 2365 omitted in which case the server will accept connections from 2366 any host. 2367 2368 ``unix:path`` 2369 Connections will be allowed over UNIX domain sockets where path 2370 is the location of a unix socket to listen for connections on. 2371 2372 ``none`` 2373 VNC is initialized but not started. The monitor ``change`` 2374 command can be used to later start the VNC server. 2375 2376 Following the display value there may be one or more option flags 2377 separated by commas. Valid options are 2378 2379 ``reverse=on|off`` 2380 Connect to a listening VNC client via a "reverse" connection. 2381 The client is specified by the display. For reverse network 2382 connections (host:d,``reverse``), the d argument is a TCP port 2383 number, not a display number. 2384 2385 ``websocket=on|off`` 2386 Opens an additional TCP listening port dedicated to VNC 2387 Websocket connections. If a bare websocket option is given, the 2388 Websocket port is 5700+display. An alternative port can be 2389 specified with the syntax ``websocket``\ =port. 2390 2391 If host is specified connections will only be allowed from this 2392 host. It is possible to control the websocket listen address 2393 independently, using the syntax ``websocket``\ =host:port. 2394 2395 If no TLS credentials are provided, the websocket connection 2396 runs in unencrypted mode. If TLS credentials are provided, the 2397 websocket connection requires encrypted client connections. 2398 2399 ``password=on|off`` 2400 Require that password based authentication is used for client 2401 connections. 2402 2403 The password must be set separately using the ``set_password`` 2404 command in the :ref:`QEMU monitor`. The 2405 syntax to change your password is: 2406 ``set_password <protocol> <password>`` where <protocol> could be 2407 either "vnc" or "spice". 2408 2409 If you would like to change <protocol> password expiration, you 2410 should use ``expire_password <protocol> <expiration-time>`` 2411 where expiration time could be one of the following options: 2412 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2413 make password expire in 60 seconds, or 1335196800 to make 2414 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2415 this date and time). 2416 2417 You can also use keywords "now" or "never" for the expiration 2418 time to allow <protocol> password to expire immediately or never 2419 expire. 2420 2421 ``password-secret=<secret-id>`` 2422 Require that password based authentication is used for client 2423 connections, using the password provided by the ``secret`` 2424 object identified by ``secret-id``. 2425 2426 ``tls-creds=ID`` 2427 Provides the ID of a set of TLS credentials to use to secure the 2428 VNC server. They will apply to both the normal VNC server socket 2429 and the websocket socket (if enabled). Setting TLS credentials 2430 will cause the VNC server socket to enable the VeNCrypt auth 2431 mechanism. The credentials should have been previously created 2432 using the ``-object tls-creds`` argument. 2433 2434 ``tls-authz=ID`` 2435 Provides the ID of the QAuthZ authorization object against which 2436 the client's x509 distinguished name will validated. This object 2437 is only resolved at time of use, so can be deleted and recreated 2438 on the fly while the VNC server is active. If missing, it will 2439 default to denying access. 2440 2441 ``sasl=on|off`` 2442 Require that the client use SASL to authenticate with the VNC 2443 server. The exact choice of authentication method used is 2444 controlled from the system / user's SASL configuration file for 2445 the 'qemu' service. This is typically found in 2446 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2447 an environment variable SASL\_CONF\_PATH can be used to make it 2448 search alternate locations for the service config. While some 2449 SASL auth methods can also provide data encryption (eg GSSAPI), 2450 it is recommended that SASL always be combined with the 'tls' 2451 and 'x509' settings to enable use of SSL and server 2452 certificates. This ensures a data encryption preventing 2453 compromise of authentication credentials. See the 2454 :ref:`VNC security` section in the System Emulation Users Guide 2455 for details on using SASL authentication. 2456 2457 ``sasl-authz=ID`` 2458 Provides the ID of the QAuthZ authorization object against which 2459 the client's SASL username will validated. This object is only 2460 resolved at time of use, so can be deleted and recreated on the 2461 fly while the VNC server is active. If missing, it will default 2462 to denying access. 2463 2464 ``acl=on|off`` 2465 Legacy method for enabling authorization of clients against the 2466 x509 distinguished name and SASL username. It results in the 2467 creation of two ``authz-list`` objects with IDs of 2468 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2469 objects must be configured with the HMP ACL commands. 2470 2471 This option is deprecated and should no longer be used. The new 2472 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2473 2474 ``lossy=on|off`` 2475 Enable lossy compression methods (gradient, JPEG, ...). If this 2476 option is set, VNC client may receive lossy framebuffer updates 2477 depending on its encoding settings. Enabling this option can 2478 save a lot of bandwidth at the expense of quality. 2479 2480 ``non-adaptive=on|off`` 2481 Disable adaptive encodings. Adaptive encodings are enabled by 2482 default. An adaptive encoding will try to detect frequently 2483 updated screen regions, and send updates in these regions using 2484 a lossy encoding (like JPEG). This can be really helpful to save 2485 bandwidth when playing videos. Disabling adaptive encodings 2486 restores the original static behavior of encodings like Tight. 2487 2488 ``share=[allow-exclusive|force-shared|ignore]`` 2489 Set display sharing policy. 'allow-exclusive' allows clients to 2490 ask for exclusive access. As suggested by the rfb spec this is 2491 implemented by dropping other connections. Connecting multiple 2492 clients in parallel requires all clients asking for a shared 2493 session (vncviewer: -shared switch). This is the default. 2494 'force-shared' disables exclusive client access. Useful for 2495 shared desktop sessions, where you don't want someone forgetting 2496 specify -shared disconnect everybody else. 'ignore' completely 2497 ignores the shared flag and allows everybody connect 2498 unconditionally. Doesn't conform to the rfb spec but is 2499 traditional QEMU behavior. 2500 2501 ``key-delay-ms`` 2502 Set keyboard delay, for key down and key up events, in 2503 milliseconds. Default is 10. Keyboards are low-bandwidth 2504 devices, so this slowdown can help the device and guest to keep 2505 up and not lose events in case events are arriving in bulk. 2506 Possible causes for the latter are flaky network connections, or 2507 scripts for automated testing. 2508 2509 ``audiodev=audiodev`` 2510 Use the specified audiodev when the VNC client requests audio 2511 transmission. When not using an -audiodev argument, this option 2512 must be omitted, otherwise is must be present and specify a 2513 valid audiodev. 2514 2515 ``power-control=on|off`` 2516 Permit the remote client to issue shutdown, reboot or reset power 2517 control requests. 2518ERST 2519 2520ARCHHEADING(, QEMU_ARCH_I386) 2521 2522ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2523 2524DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2525 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2526 QEMU_ARCH_I386) 2527SRST 2528``-win2k-hack`` 2529 Use it when installing Windows 2000 to avoid a disk full bug. After 2530 Windows 2000 is installed, you no longer need this option (this 2531 option slows down the IDE transfers). 2532ERST 2533 2534DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2535 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2536 QEMU_ARCH_I386) 2537SRST 2538``-no-fd-bootchk`` 2539 Disable boot signature checking for floppy disks in BIOS. May be 2540 needed to boot from old floppy disks. 2541ERST 2542 2543DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2544 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2545SRST 2546``-no-acpi`` 2547 Disable ACPI (Advanced Configuration and Power Interface) support. 2548 Use it if your guest OS complains about ACPI problems (PC target 2549 machine only). 2550ERST 2551 2552DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2553 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2554SRST 2555``-no-hpet`` 2556 Disable HPET support. 2557ERST 2558 2559DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2560 "-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" 2561 " ACPI table description\n", QEMU_ARCH_I386) 2562SRST 2563``-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]...]`` 2564 Add ACPI table with specified header fields and context from 2565 specified files. For file=, take whole ACPI table from the specified 2566 files, including all ACPI headers (possible overridden by other 2567 options). For data=, only data portion of the table is used, all 2568 header information is specified in the command line. If a SLIC table 2569 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2570 fields will override the same in the RSDT and the FADT (a.k.a. 2571 FACP), in order to ensure the field matches required by the 2572 Microsoft SLIC spec and the ACPI spec. 2573ERST 2574 2575DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2576 "-smbios file=binary\n" 2577 " load SMBIOS entry from binary file\n" 2578 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2579 " [,uefi=on|off]\n" 2580 " specify SMBIOS type 0 fields\n" 2581 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2582 " [,uuid=uuid][,sku=str][,family=str]\n" 2583 " specify SMBIOS type 1 fields\n" 2584 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2585 " [,asset=str][,location=str]\n" 2586 " specify SMBIOS type 2 fields\n" 2587 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2588 " [,sku=str]\n" 2589 " specify SMBIOS type 3 fields\n" 2590 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2591 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2592 " [,processor-id=%d]\n" 2593 " specify SMBIOS type 4 fields\n" 2594 "-smbios type=11[,value=str][,path=filename]\n" 2595 " specify SMBIOS type 11 fields\n" 2596 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2597 " [,asset=str][,part=str][,speed=%d]\n" 2598 " specify SMBIOS type 17 fields\n" 2599 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2600 " specify SMBIOS type 41 fields\n", 2601 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2602SRST 2603``-smbios file=binary`` 2604 Load SMBIOS entry from binary file. 2605 2606``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2607 Specify SMBIOS type 0 fields 2608 2609``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2610 Specify SMBIOS type 1 fields 2611 2612``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2613 Specify SMBIOS type 2 fields 2614 2615``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2616 Specify SMBIOS type 3 fields 2617 2618``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2619 Specify SMBIOS type 4 fields 2620 2621``-smbios type=11[,value=str][,path=filename]`` 2622 Specify SMBIOS type 11 fields 2623 2624 This argument can be repeated multiple times, and values are added in the order they are parsed. 2625 Applications intending to use OEM strings data are encouraged to use their application name as 2626 a prefix for the value string. This facilitates passing information for multiple applications 2627 concurrently. 2628 2629 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2630 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2631 2632 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2633 the SMBIOS table in the order in which they appear. 2634 2635 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2636 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2637 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2638 data set, for example, by specifying the serial ID of a block device. 2639 2640 An example passing three strings is 2641 2642 .. parsed-literal:: 2643 2644 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2645 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2646 path=/some/file/with/oemstringsdata.txt 2647 2648 In the guest OS this is visible with the ``dmidecode`` command 2649 2650 .. parsed-literal:: 2651 2652 $ dmidecode -t 11 2653 Handle 0x0E00, DMI type 11, 5 bytes 2654 OEM Strings 2655 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2656 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2657 String 3: myapp:some extra data 2658 2659 2660``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2661 Specify SMBIOS type 17 fields 2662 2663``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2664 Specify SMBIOS type 41 fields 2665 2666 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2667 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2668 position on the PCI bus. 2669 2670 Here is an example of use: 2671 2672 .. parsed-literal:: 2673 2674 -netdev user,id=internet \\ 2675 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2676 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2677 2678 In the guest OS, the device should then appear as ``eno1``: 2679 2680 ..parsed-literal:: 2681 2682 $ ip -brief l 2683 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2684 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2685 2686 Currently, the PCI device has to be attached to the root bus. 2687 2688ERST 2689 2690DEFHEADING() 2691 2692DEFHEADING(Network options:) 2693 2694DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2695#ifdef CONFIG_SLIRP 2696 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2697 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2698 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2699 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2700 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2701#ifndef _WIN32 2702 "[,smb=dir[,smbserver=addr]]\n" 2703#endif 2704 " configure a user mode network backend with ID 'str',\n" 2705 " its DHCP server and optional services\n" 2706#endif 2707#ifdef _WIN32 2708 "-netdev tap,id=str,ifname=name\n" 2709 " configure a host TAP network backend with ID 'str'\n" 2710#else 2711 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2712 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2713 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2714 " [,poll-us=n]\n" 2715 " configure a host TAP network backend with ID 'str'\n" 2716 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2717 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2718 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2719 " to deconfigure it\n" 2720 " use '[down]script=no' to disable script execution\n" 2721 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2722 " configure it\n" 2723 " use 'fd=h' to connect to an already opened TAP interface\n" 2724 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2725 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2726 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2727 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2728 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2729 " use vhost=on to enable experimental in kernel accelerator\n" 2730 " (only has effect for virtio guests which use MSIX)\n" 2731 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2732 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2733 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2734 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2735 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2736 " spent on busy polling for vhost net\n" 2737 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2738 " configure a host TAP network backend with ID 'str' that is\n" 2739 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2740 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2741#endif 2742#ifdef __linux__ 2743 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2744 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2745 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2746 " [,rxcookie=rxcookie][,offset=offset]\n" 2747 " configure a network backend with ID 'str' connected to\n" 2748 " an Ethernet over L2TPv3 pseudowire.\n" 2749 " Linux kernel 3.3+ as well as most routers can talk\n" 2750 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2751 " VM to a router and even VM to Host. It is a nearly-universal\n" 2752 " standard (RFC3931). Note - this implementation uses static\n" 2753 " pre-configured tunnels (same as the Linux kernel).\n" 2754 " use 'src=' to specify source address\n" 2755 " use 'dst=' to specify destination address\n" 2756 " use 'udp=on' to specify udp encapsulation\n" 2757 " use 'srcport=' to specify source udp port\n" 2758 " use 'dstport=' to specify destination udp port\n" 2759 " use 'ipv6=on' to force v6\n" 2760 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2761 " well as a weak security measure\n" 2762 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2763 " use 'txcookie=0x012345678' to specify a txcookie\n" 2764 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2765 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2766 " use 'pincounter=on' to work around broken counter handling in peer\n" 2767 " use 'offset=X' to add an extra offset between header and data\n" 2768#endif 2769 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2770 " configure a network backend to connect to another network\n" 2771 " using a socket connection\n" 2772 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2773 " configure a network backend to connect to a multicast maddr and port\n" 2774 " use 'localaddr=addr' to specify the host address to send packets from\n" 2775 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2776 " configure a network backend to connect to another network\n" 2777 " using an UDP tunnel\n" 2778#ifdef CONFIG_VDE 2779 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2780 " configure a network backend to connect to port 'n' of a vde switch\n" 2781 " running on host and listening for incoming connections on 'socketpath'.\n" 2782 " Use group 'groupname' and mode 'octalmode' to change default\n" 2783 " ownership and permissions for communication port.\n" 2784#endif 2785#ifdef CONFIG_NETMAP 2786 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2787 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2788 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2789 " netmap device, defaults to '/dev/netmap')\n" 2790#endif 2791#ifdef CONFIG_POSIX 2792 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2793 " configure a vhost-user network, backed by a chardev 'dev'\n" 2794#endif 2795#ifdef __linux__ 2796 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2797 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2798#endif 2799#ifdef CONFIG_VMNET 2800 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2801 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2802 " configure a vmnet network backend in host mode with ID 'str',\n" 2803 " isolate this interface from others with 'isolated',\n" 2804 " configure the address range and choose a subnet mask,\n" 2805 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2806 " vmnet-host interfaces within this isolated network\n" 2807 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2808 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2809 " configure a vmnet network backend in shared mode with ID 'str',\n" 2810 " configure the address range and choose a subnet mask,\n" 2811 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2812 " isolate this interface from others with 'isolated'\n" 2813 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2814 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2815 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2816 " isolate this interface from others with 'isolated'\n" 2817#endif 2818 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2819 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2820DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2821 "-nic [tap|bridge|" 2822#ifdef CONFIG_SLIRP 2823 "user|" 2824#endif 2825#ifdef __linux__ 2826 "l2tpv3|" 2827#endif 2828#ifdef CONFIG_VDE 2829 "vde|" 2830#endif 2831#ifdef CONFIG_NETMAP 2832 "netmap|" 2833#endif 2834#ifdef CONFIG_POSIX 2835 "vhost-user|" 2836#endif 2837#ifdef CONFIG_VMNET 2838 "vmnet-host|vmnet-shared|vmnet-bridged|" 2839#endif 2840 "socket][,option][,...][mac=macaddr]\n" 2841 " initialize an on-board / default host NIC (using MAC address\n" 2842 " macaddr) and connect it to the given host network backend\n" 2843 "-nic none use it alone to have zero network devices (the default is to\n" 2844 " provided a 'user' network connection)\n", 2845 QEMU_ARCH_ALL) 2846DEF("net", HAS_ARG, QEMU_OPTION_net, 2847 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2848 " configure or create an on-board (or machine default) NIC and\n" 2849 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2850 "-net [" 2851#ifdef CONFIG_SLIRP 2852 "user|" 2853#endif 2854 "tap|" 2855 "bridge|" 2856#ifdef CONFIG_VDE 2857 "vde|" 2858#endif 2859#ifdef CONFIG_NETMAP 2860 "netmap|" 2861#endif 2862#ifdef CONFIG_VMNET 2863 "vmnet-host|vmnet-shared|vmnet-bridged|" 2864#endif 2865 "socket][,option][,option][,...]\n" 2866 " old way to initialize a host network interface\n" 2867 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2868SRST 2869``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2870 This option is a shortcut for configuring both the on-board 2871 (default) guest NIC hardware and the host network backend in one go. 2872 The host backend options are the same as with the corresponding 2873 ``-netdev`` options below. The guest NIC model can be set with 2874 ``model=modelname``. Use ``model=help`` to list the available device 2875 types. The hardware MAC address can be set with ``mac=macaddr``. 2876 2877 The following two example do exactly the same, to show how ``-nic`` 2878 can be used to shorten the command line length: 2879 2880 .. parsed-literal:: 2881 2882 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2883 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2884 2885``-nic none`` 2886 Indicate that no network devices should be configured. It is used to 2887 override the default configuration (default NIC with "user" host 2888 network backend) which is activated if no other networking options 2889 are provided. 2890 2891``-netdev user,id=id[,option][,option][,...]`` 2892 Configure user mode host network backend which requires no 2893 administrator privilege to run. Valid options are: 2894 2895 ``id=id`` 2896 Assign symbolic name for use in monitor commands. 2897 2898 ``ipv4=on|off and ipv6=on|off`` 2899 Specify that either IPv4 or IPv6 must be enabled. If neither is 2900 specified both protocols are enabled. 2901 2902 ``net=addr[/mask]`` 2903 Set IP network address the guest will see. Optionally specify 2904 the netmask, either in the form a.b.c.d or as number of valid 2905 top-most bits. Default is 10.0.2.0/24. 2906 2907 ``host=addr`` 2908 Specify the guest-visible address of the host. Default is the 2909 2nd IP in the guest network, i.e. x.x.x.2. 2910 2911 ``ipv6-net=addr[/int]`` 2912 Set IPv6 network address the guest will see (default is 2913 fec0::/64). The network prefix is given in the usual hexadecimal 2914 IPv6 address notation. The prefix size is optional, and is given 2915 as the number of valid top-most bits (default is 64). 2916 2917 ``ipv6-host=addr`` 2918 Specify the guest-visible IPv6 address of the host. Default is 2919 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2920 2921 ``restrict=on|off`` 2922 If this option is enabled, the guest will be isolated, i.e. it 2923 will not be able to contact the host and no guest IP packets 2924 will be routed over the host to the outside. This option does 2925 not affect any explicitly set forwarding rules. 2926 2927 ``hostname=name`` 2928 Specifies the client hostname reported by the built-in DHCP 2929 server. 2930 2931 ``dhcpstart=addr`` 2932 Specify the first of the 16 IPs the built-in DHCP server can 2933 assign. Default is the 15th to 31st IP in the guest network, 2934 i.e. x.x.x.15 to x.x.x.31. 2935 2936 ``dns=addr`` 2937 Specify the guest-visible address of the virtual nameserver. The 2938 address must be different from the host address. Default is the 2939 3rd IP in the guest network, i.e. x.x.x.3. 2940 2941 ``ipv6-dns=addr`` 2942 Specify the guest-visible address of the IPv6 virtual 2943 nameserver. The address must be different from the host address. 2944 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2945 2946 ``dnssearch=domain`` 2947 Provides an entry for the domain-search list sent by the 2948 built-in DHCP server. More than one domain suffix can be 2949 transmitted by specifying this option multiple times. If 2950 supported, this will cause the guest to automatically try to 2951 append the given domain suffix(es) in case a domain name can not 2952 be resolved. 2953 2954 Example: 2955 2956 .. parsed-literal:: 2957 2958 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2959 2960 ``domainname=domain`` 2961 Specifies the client domain name reported by the built-in DHCP 2962 server. 2963 2964 ``tftp=dir`` 2965 When using the user mode network stack, activate a built-in TFTP 2966 server. The files in dir will be exposed as the root of a TFTP 2967 server. The TFTP client on the guest must be configured in 2968 binary mode (use the command ``bin`` of the Unix TFTP client). 2969 2970 ``tftp-server-name=name`` 2971 In BOOTP reply, broadcast name as the "TFTP server name" 2972 (RFC2132 option 66). This can be used to advise the guest to 2973 load boot files or configurations from a different server than 2974 the host address. 2975 2976 ``bootfile=file`` 2977 When using the user mode network stack, broadcast file as the 2978 BOOTP filename. In conjunction with ``tftp``, this can be used 2979 to network boot a guest from a local directory. 2980 2981 Example (using pxelinux): 2982 2983 .. parsed-literal:: 2984 2985 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2986 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2987 2988 ``smb=dir[,smbserver=addr]`` 2989 When using the user mode network stack, activate a built-in SMB 2990 server so that Windows OSes can access to the host files in 2991 ``dir`` transparently. The IP address of the SMB server can be 2992 set to addr. By default the 4th IP in the guest network is used, 2993 i.e. x.x.x.4. 2994 2995 In the guest Windows OS, the line: 2996 2997 :: 2998 2999 10.0.2.4 smbserver 3000 3001 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3002 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3003 NT/2000). 3004 3005 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3006 3007 Note that a SAMBA server must be installed on the host OS. 3008 3009 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3010 Redirect incoming TCP or UDP connections to the host port 3011 hostport to the guest IP address guestaddr on guest port 3012 guestport. If guestaddr is not specified, its value is x.x.x.15 3013 (default first address given by the built-in DHCP server). By 3014 specifying hostaddr, the rule can be bound to a specific host 3015 interface. If no connection type is set, TCP is used. This 3016 option can be given multiple times. 3017 3018 For example, to redirect host X11 connection from screen 1 to 3019 guest screen 0, use the following: 3020 3021 .. parsed-literal:: 3022 3023 # on the host 3024 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3025 # this host xterm should open in the guest X11 server 3026 xterm -display :1 3027 3028 To redirect telnet connections from host port 5555 to telnet 3029 port on the guest, use the following: 3030 3031 .. parsed-literal:: 3032 3033 # on the host 3034 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3035 telnet localhost 5555 3036 3037 Then when you use on the host ``telnet localhost 5555``, you 3038 connect to the guest telnet server. 3039 3040 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3041 Forward guest TCP connections to the IP address server on port 3042 port to the character device dev or to a program executed by 3043 cmd:command which gets spawned for each connection. This option 3044 can be given multiple times. 3045 3046 You can either use a chardev directly and have that one used 3047 throughout QEMU's lifetime, like in the following example: 3048 3049 .. parsed-literal:: 3050 3051 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3052 # the guest accesses it 3053 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3054 3055 Or you can execute a command on every TCP connection established 3056 by the guest, so that QEMU behaves similar to an inetd process 3057 for that virtual server: 3058 3059 .. parsed-literal:: 3060 3061 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3062 # and connect the TCP stream to its stdin/stdout 3063 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3064 3065``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3066 Configure a host TAP network backend with ID id. 3067 3068 Use the network script file to configure it and the network script 3069 dfile to deconfigure it. If name is not provided, the OS 3070 automatically provides one. The default network configure script is 3071 ``/etc/qemu-ifup`` and the default network deconfigure script is 3072 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3073 disable script execution. 3074 3075 If running QEMU as an unprivileged user, use the network helper 3076 to configure the TAP interface and attach it to the bridge. 3077 The default network helper executable is 3078 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3079 ``br0``. 3080 3081 ``fd``\ =h can be used to specify the handle of an already opened 3082 host TAP interface. 3083 3084 Examples: 3085 3086 .. parsed-literal:: 3087 3088 #launch a QEMU instance with the default network script 3089 |qemu_system| linux.img -nic tap 3090 3091 .. parsed-literal:: 3092 3093 #launch a QEMU instance with two NICs, each one connected 3094 #to a TAP device 3095 |qemu_system| linux.img \\ 3096 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3097 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3098 3099 .. parsed-literal:: 3100 3101 #launch a QEMU instance with the default network helper to 3102 #connect a TAP device to bridge br0 3103 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3104 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3105 3106``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3107 Connect a host TAP network interface to a host bridge device. 3108 3109 Use the network helper helper to configure the TAP interface and 3110 attach it to the bridge. The default network helper executable is 3111 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3112 ``br0``. 3113 3114 Examples: 3115 3116 .. parsed-literal:: 3117 3118 #launch a QEMU instance with the default network helper to 3119 #connect a TAP device to bridge br0 3120 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3121 3122 .. parsed-literal:: 3123 3124 #launch a QEMU instance with the default network helper to 3125 #connect a TAP device to bridge qemubr0 3126 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3127 3128``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3129 This host network backend can be used to connect the guest's network 3130 to another QEMU virtual machine using a TCP socket connection. If 3131 ``listen`` is specified, QEMU waits for incoming connections on port 3132 (host is optional). ``connect`` is used to connect to another QEMU 3133 instance using the ``listen`` option. ``fd``\ =h specifies an 3134 already opened TCP socket. 3135 3136 Example: 3137 3138 .. parsed-literal:: 3139 3140 # launch a first QEMU instance 3141 |qemu_system| linux.img \\ 3142 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3143 -netdev socket,id=n1,listen=:1234 3144 # connect the network of this instance to the network of the first instance 3145 |qemu_system| linux.img \\ 3146 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3147 -netdev socket,id=n2,connect=127.0.0.1:1234 3148 3149``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3150 Configure a socket host network backend to share the guest's network 3151 traffic with another QEMU virtual machines using a UDP multicast 3152 socket, effectively making a bus for every QEMU with same multicast 3153 address maddr and port. NOTES: 3154 3155 1. Several QEMU can be running on different hosts and share same bus 3156 (assuming correct multicast setup for these hosts). 3157 3158 2. mcast support is compatible with User Mode Linux (argument 3159 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3160 3161 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3162 3163 Example: 3164 3165 .. parsed-literal:: 3166 3167 # launch one QEMU instance 3168 |qemu_system| linux.img \\ 3169 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3170 -netdev socket,id=n1,mcast=230.0.0.1:1234 3171 # launch another QEMU instance on same "bus" 3172 |qemu_system| linux.img \\ 3173 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3174 -netdev socket,id=n2,mcast=230.0.0.1:1234 3175 # launch yet another QEMU instance on same "bus" 3176 |qemu_system| linux.img \\ 3177 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3178 -netdev socket,id=n3,mcast=230.0.0.1:1234 3179 3180 Example (User Mode Linux compat.): 3181 3182 .. parsed-literal:: 3183 3184 # launch QEMU instance (note mcast address selected is UML's default) 3185 |qemu_system| linux.img \\ 3186 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3187 -netdev socket,id=n1,mcast=239.192.168.1:1102 3188 # launch UML 3189 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3190 3191 Example (send packets from host's 1.2.3.4): 3192 3193 .. parsed-literal:: 3194 3195 |qemu_system| linux.img \\ 3196 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3197 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3198 3199``-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]`` 3200 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3201 is a popular protocol to transport Ethernet (and other Layer 2) data 3202 frames between two systems. It is present in routers, firewalls and 3203 the Linux kernel (from version 3.3 onwards). 3204 3205 This transport allows a VM to communicate to another VM, router or 3206 firewall directly. 3207 3208 ``src=srcaddr`` 3209 source address (mandatory) 3210 3211 ``dst=dstaddr`` 3212 destination address (mandatory) 3213 3214 ``udp`` 3215 select udp encapsulation (default is ip). 3216 3217 ``srcport=srcport`` 3218 source udp port. 3219 3220 ``dstport=dstport`` 3221 destination udp port. 3222 3223 ``ipv6`` 3224 force v6, otherwise defaults to v4. 3225 3226 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3227 Cookies are a weak form of security in the l2tpv3 specification. 3228 Their function is mostly to prevent misconfiguration. By default 3229 they are 32 bit. 3230 3231 ``cookie64`` 3232 Set cookie size to 64 bit instead of the default 32 3233 3234 ``counter=off`` 3235 Force a 'cut-down' L2TPv3 with no counter as in 3236 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3237 3238 ``pincounter=on`` 3239 Work around broken counter handling in peer. This may also help 3240 on networks which have packet reorder. 3241 3242 ``offset=offset`` 3243 Add an extra offset between header and data 3244 3245 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3246 the bridge br-lan on the remote Linux host 1.2.3.4: 3247 3248 .. parsed-literal:: 3249 3250 # Setup tunnel on linux host using raw ip as encapsulation 3251 # on 1.2.3.4 3252 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3253 encap udp udp_sport 16384 udp_dport 16384 3254 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3255 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3256 ifconfig vmtunnel0 mtu 1500 3257 ifconfig vmtunnel0 up 3258 brctl addif br-lan vmtunnel0 3259 3260 3261 # on 4.3.2.1 3262 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3263 3264 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3265 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3266 3267``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3268 Configure VDE backend to connect to PORT n of a vde switch running 3269 on host and listening for incoming connections on socketpath. Use 3270 GROUP groupname and MODE octalmode to change default ownership and 3271 permissions for communication port. This option is only available if 3272 QEMU has been compiled with vde support enabled. 3273 3274 Example: 3275 3276 .. parsed-literal:: 3277 3278 # launch vde switch 3279 vde_switch -F -sock /tmp/myswitch 3280 # launch QEMU instance 3281 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3282 3283``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3284 Establish a vhost-user netdev, backed by a chardev id. The chardev 3285 should be a unix domain socket backed one. The vhost-user uses a 3286 specifically defined protocol to pass vhost ioctl replacement 3287 messages to an application on the other end of the socket. On 3288 non-MSIX guests, the feature can be forced with vhostforce. Use 3289 'queues=n' to specify the number of queues to be created for 3290 multiqueue vhost-user. 3291 3292 Example: 3293 3294 :: 3295 3296 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3297 -numa node,memdev=mem \ 3298 -chardev socket,id=chr0,path=/path/to/socket \ 3299 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3300 -device virtio-net-pci,netdev=net0 3301 3302``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3303 Establish a vhost-vdpa netdev. 3304 3305 vDPA device is a device that uses a datapath which complies with 3306 the virtio specifications with a vendor specific control path. 3307 vDPA devices can be both physically located on the hardware or 3308 emulated by software. 3309 3310``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3311 Create a hub port on the emulated hub with ID hubid. 3312 3313 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3314 instead of a single netdev. Alternatively, you can also connect the 3315 hubport to another netdev with ID nd by using the ``netdev=nd`` 3316 option. 3317 3318``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3319 Legacy option to configure or create an on-board (or machine 3320 default) Network Interface Card(NIC) and connect it either to the 3321 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3322 If model is omitted, then the default NIC model associated with the 3323 machine type is used. Note that the default NIC model may change in 3324 future QEMU releases, so it is highly recommended to always specify 3325 a model. Optionally, the MAC address can be changed to mac, the 3326 device address set to addr (PCI cards only), and a name can be 3327 assigned for use in monitor commands. Optionally, for PCI cards, you 3328 can specify the number v of MSI-X vectors that the card should have; 3329 this option currently only affects virtio cards; set v = 0 to 3330 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3331 created. QEMU can emulate several different models of network card. 3332 Use ``-net nic,model=help`` for a list of available devices for your 3333 target. 3334 3335``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3336 Configure a host network backend (with the options corresponding to 3337 the same ``-netdev`` option) and connect it to the emulated hub 0 3338 (the default hub). Use name to specify the name of the hub port. 3339ERST 3340 3341DEFHEADING() 3342 3343DEFHEADING(Character device options:) 3344 3345DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3346 "-chardev help\n" 3347 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3348 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3349 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3350 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3351 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3352 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3353 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3354 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3355 " [,logfile=PATH][,logappend=on|off]\n" 3356 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3357 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3358 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3359 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3360 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3361 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3362#ifdef _WIN32 3363 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3364 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3365#else 3366 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3367 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3368#endif 3369#ifdef CONFIG_BRLAPI 3370 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3371#endif 3372#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3373 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3374 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3375 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3376#endif 3377#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3378 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3379 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3380#endif 3381#if defined(CONFIG_SPICE) 3382 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3383 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3384#endif 3385 , QEMU_ARCH_ALL 3386) 3387 3388SRST 3389The general form of a character device option is: 3390 3391``-chardev backend,id=id[,mux=on|off][,options]`` 3392 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3393 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3394 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3395 ``spicevmc``, ``spiceport``. The specific backend will determine the 3396 applicable options. 3397 3398 Use ``-chardev help`` to print all available chardev backend types. 3399 3400 All devices must have an id, which can be any string up to 127 3401 characters long. It is used to uniquely identify this device in 3402 other command line directives. 3403 3404 A character device may be used in multiplexing mode by multiple 3405 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3406 a "1:N" device, and here the "1" end is your specified chardev 3407 backend, and the "N" end is the various parts of QEMU that can talk 3408 to a chardev. If you create a chardev with ``id=myid`` and 3409 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3410 and you can then configure multiple front ends to use that chardev 3411 ID for their input/output. Up to four different front ends can be 3412 connected to a single multiplexed chardev. (Without multiplexing 3413 enabled, a chardev can only be used by a single front end.) For 3414 instance you could use this to allow a single stdio chardev to be 3415 used by two serial ports and the QEMU monitor: 3416 3417 :: 3418 3419 -chardev stdio,mux=on,id=char0 \ 3420 -mon chardev=char0,mode=readline \ 3421 -serial chardev:char0 \ 3422 -serial chardev:char0 3423 3424 You can have more than one multiplexer in a system configuration; 3425 for instance you could have a TCP port multiplexed between UART 0 3426 and UART 1, and stdio multiplexed between the QEMU monitor and a 3427 parallel port: 3428 3429 :: 3430 3431 -chardev stdio,mux=on,id=char0 \ 3432 -mon chardev=char0,mode=readline \ 3433 -parallel chardev:char0 \ 3434 -chardev tcp,...,mux=on,id=char1 \ 3435 -serial chardev:char1 \ 3436 -serial chardev:char1 3437 3438 When you're using a multiplexed character device, some escape 3439 sequences are interpreted in the input. See the chapter about 3440 :ref:`keys in the character backend multiplexer` in the 3441 System Emulation Users Guide for more details. 3442 3443 Note that some other command line options may implicitly create 3444 multiplexed character backends; for instance ``-serial mon:stdio`` 3445 creates a multiplexed stdio backend connected to the serial port and 3446 the QEMU monitor, and ``-nographic`` also multiplexes the console 3447 and the monitor to stdio. 3448 3449 There is currently no support for multiplexing in the other 3450 direction (where a single QEMU front end takes input and output from 3451 multiple chardevs). 3452 3453 Every backend supports the ``logfile`` option, which supplies the 3454 path to a file to record all data transmitted via the backend. The 3455 ``logappend`` option controls whether the log file will be truncated 3456 or appended to when opened. 3457 3458The available backends are: 3459 3460``-chardev null,id=id`` 3461 A void device. This device will not emit any data, and will drop any 3462 data it receives. The null backend does not take any options. 3463 3464``-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]`` 3465 Create a two-way stream socket, which can be either a TCP or a unix 3466 socket. A unix socket will be created if ``path`` is specified. 3467 Behaviour is undefined if TCP options are specified for a unix 3468 socket. 3469 3470 ``server=on|off`` specifies that the socket shall be a listening socket. 3471 3472 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3473 to connect to a listening socket. 3474 3475 ``telnet=on|off`` specifies that traffic on the socket should interpret 3476 telnet escape sequences. 3477 3478 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3479 communication. 3480 3481 ``reconnect`` sets the timeout for reconnecting on non-server 3482 sockets when the remote end goes away. qemu will delay this many 3483 seconds and then attempt to reconnect. Zero disables reconnecting, 3484 and is the default. 3485 3486 ``tls-creds`` requests enablement of the TLS protocol for 3487 encryption, and specifies the id of the TLS credentials to use for 3488 the handshake. The credentials must be previously created with the 3489 ``-object tls-creds`` argument. 3490 3491 ``tls-auth`` provides the ID of the QAuthZ authorization object 3492 against which the client's x509 distinguished name will be 3493 validated. This object is only resolved at time of use, so can be 3494 deleted and recreated on the fly while the chardev server is active. 3495 If missing, it will default to denying access. 3496 3497 TCP and unix socket options are given below: 3498 3499 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3500 ``host`` for a listening socket specifies the local address to 3501 be bound. For a connecting socket species the remote host to 3502 connect to. ``host`` is optional for listening sockets. If not 3503 specified it defaults to ``0.0.0.0``. 3504 3505 ``port`` for a listening socket specifies the local port to be 3506 bound. For a connecting socket specifies the port on the remote 3507 host to connect to. ``port`` can be given as either a port 3508 number or a service name. ``port`` is required. 3509 3510 ``to`` is only relevant to listening sockets. If it is 3511 specified, and ``port`` cannot be bound, QEMU will attempt to 3512 bind to subsequent ports up to and including ``to`` until it 3513 succeeds. ``to`` must be specified as a port number. 3514 3515 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3516 or IPv6 must be used. If neither is specified the socket may 3517 use either protocol. 3518 3519 ``nodelay=on|off`` disables the Nagle algorithm. 3520 3521 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3522 ``path`` specifies the local path of the unix socket. ``path`` 3523 is required. 3524 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3525 rather than the filesystem. Optional, defaults to false. 3526 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3527 rather than the full sun_path length. Optional, defaults to true. 3528 3529``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3530 Sends all traffic from the guest to a remote host over UDP. 3531 3532 ``host`` specifies the remote host to connect to. If not specified 3533 it defaults to ``localhost``. 3534 3535 ``port`` specifies the port on the remote host to connect to. 3536 ``port`` is required. 3537 3538 ``localaddr`` specifies the local address to bind to. If not 3539 specified it defaults to ``0.0.0.0``. 3540 3541 ``localport`` specifies the local port to bind to. If not specified 3542 any available local port will be used. 3543 3544 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3545 If neither is specified the device may use either protocol. 3546 3547``-chardev msmouse,id=id`` 3548 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3549 does not take any options. 3550 3551``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3552 Connect to a QEMU text console. ``vc`` may optionally be given a 3553 specific size. 3554 3555 ``width`` and ``height`` specify the width and height respectively 3556 of the console, in pixels. 3557 3558 ``cols`` and ``rows`` specify that the console be sized to fit a 3559 text console with the given dimensions. 3560 3561``-chardev ringbuf,id=id[,size=size]`` 3562 Create a ring buffer with fixed size ``size``. size must be a power 3563 of two and defaults to ``64K``. 3564 3565``-chardev file,id=id,path=path`` 3566 Log all traffic received from the guest to a file. 3567 3568 ``path`` specifies the path of the file to be opened. This file will 3569 be created if it does not already exist, and overwritten if it does. 3570 ``path`` is required. 3571 3572``-chardev pipe,id=id,path=path`` 3573 Create a two-way connection to the guest. The behaviour differs 3574 slightly between Windows hosts and other hosts: 3575 3576 On Windows, a single duplex pipe will be created at 3577 ``\\.pipe\path``. 3578 3579 On other hosts, 2 pipes will be created called ``path.in`` and 3580 ``path.out``. Data written to ``path.in`` will be received by the 3581 guest. Data written by the guest can be read from ``path.out``. QEMU 3582 will not create these fifos, and requires them to be present. 3583 3584 ``path`` forms part of the pipe path as described above. ``path`` is 3585 required. 3586 3587``-chardev console,id=id`` 3588 Send traffic from the guest to QEMU's standard output. ``console`` 3589 does not take any options. 3590 3591 ``console`` is only available on Windows hosts. 3592 3593``-chardev serial,id=id,path=path`` 3594 Send traffic from the guest to a serial device on the host. 3595 3596 On Unix hosts serial will actually accept any tty device, not only 3597 serial lines. 3598 3599 ``path`` specifies the name of the serial device to open. 3600 3601``-chardev pty,id=id`` 3602 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3603 does not take any options. 3604 3605 ``pty`` is not available on Windows hosts. 3606 3607``-chardev stdio,id=id[,signal=on|off]`` 3608 Connect to standard input and standard output of the QEMU process. 3609 3610 ``signal`` controls if signals are enabled on the terminal, that 3611 includes exiting QEMU with the key sequence Control-c. This option 3612 is enabled by default, use ``signal=off`` to disable it. 3613 3614``-chardev braille,id=id`` 3615 Connect to a local BrlAPI server. ``braille`` does not take any 3616 options. 3617 3618``-chardev tty,id=id,path=path`` 3619 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3620 and DragonFlyBSD hosts. It is an alias for ``serial``. 3621 3622 ``path`` specifies the path to the tty. ``path`` is required. 3623 3624``-chardev parallel,id=id,path=path`` 3625 \ 3626``-chardev parport,id=id,path=path`` 3627 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3628 hosts. 3629 3630 Connect to a local parallel port. 3631 3632 ``path`` specifies the path to the parallel port device. ``path`` is 3633 required. 3634 3635``-chardev spicevmc,id=id,debug=debug,name=name`` 3636 ``spicevmc`` is only available when spice support is built in. 3637 3638 ``debug`` debug level for spicevmc 3639 3640 ``name`` name of spice channel to connect to 3641 3642 Connect to a spice virtual machine channel, such as vdiport. 3643 3644``-chardev spiceport,id=id,debug=debug,name=name`` 3645 ``spiceport`` is only available when spice support is built in. 3646 3647 ``debug`` debug level for spicevmc 3648 3649 ``name`` name of spice port to connect to 3650 3651 Connect to a spice port, allowing a Spice client to handle the 3652 traffic identified by a name (preferably a fqdn). 3653ERST 3654 3655DEFHEADING() 3656 3657#ifdef CONFIG_TPM 3658DEFHEADING(TPM device options:) 3659 3660DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3661 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3662 " use path to provide path to a character device; default is /dev/tpm0\n" 3663 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3664 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3665 "-tpmdev emulator,id=id,chardev=dev\n" 3666 " configure the TPM device using chardev backend\n", 3667 QEMU_ARCH_ALL) 3668SRST 3669The general form of a TPM device option is: 3670 3671``-tpmdev backend,id=id[,options]`` 3672 The specific backend type will determine the applicable options. The 3673 ``-tpmdev`` option creates the TPM backend and requires a 3674 ``-device`` option that specifies the TPM frontend interface model. 3675 3676 Use ``-tpmdev help`` to print all available TPM backend types. 3677 3678The available backends are: 3679 3680``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3681 (Linux-host only) Enable access to the host's TPM using the 3682 passthrough driver. 3683 3684 ``path`` specifies the path to the host's TPM device, i.e., on a 3685 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3686 default ``/dev/tpm0`` is used. 3687 3688 ``cancel-path`` specifies the path to the host TPM device's sysfs 3689 entry allowing for cancellation of an ongoing TPM command. 3690 ``cancel-path`` is optional and by default QEMU will search for the 3691 sysfs entry to use. 3692 3693 Some notes about using the host's TPM with the passthrough driver: 3694 3695 The TPM device accessed by the passthrough driver must not be used 3696 by any other application on the host. 3697 3698 Since the host's firmware (BIOS/UEFI) has already initialized the 3699 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3700 the TPM again and may therefore not show a TPM-specific menu that 3701 would otherwise allow the user to configure the TPM, e.g., allow the 3702 user to enable/disable or activate/deactivate the TPM. Further, if 3703 TPM ownership is released from within a VM then the host's TPM will 3704 get disabled and deactivated. To enable and activate the TPM again 3705 afterwards, the host has to be rebooted and the user is required to 3706 enter the firmware's menu to enable and activate the TPM. If the TPM 3707 is left disabled and/or deactivated most TPM commands will fail. 3708 3709 To create a passthrough TPM use the following two options: 3710 3711 :: 3712 3713 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3714 3715 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3716 ``tpmdev=tpm0`` in the device option. 3717 3718``-tpmdev emulator,id=id,chardev=dev`` 3719 (Linux-host only) Enable access to a TPM emulator using Unix domain 3720 socket based chardev backend. 3721 3722 ``chardev`` specifies the unique ID of a character device backend 3723 that provides connection to the software TPM server. 3724 3725 To create a TPM emulator backend device with chardev socket backend: 3726 3727 :: 3728 3729 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3730ERST 3731 3732DEFHEADING() 3733 3734#endif 3735 3736DEFHEADING(Linux/Multiboot boot specific:) 3737SRST 3738When using these options, you can use a given Linux or Multiboot kernel 3739without installing it in the disk image. It can be useful for easier 3740testing of various kernels. 3741 3742 3743ERST 3744 3745DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3746 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3747SRST 3748``-kernel bzImage`` 3749 Use bzImage as kernel image. The kernel can be either a Linux kernel 3750 or in multiboot format. 3751ERST 3752 3753DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3754 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3755SRST 3756``-append cmdline`` 3757 Use cmdline as kernel command line 3758ERST 3759 3760DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3761 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3762SRST 3763``-initrd file`` 3764 Use file as initial ram disk. 3765 3766``-initrd "file1 arg=foo,file2"`` 3767 This syntax is only available with multiboot. 3768 3769 Use file1 and file2 as modules and pass arg=foo as parameter to the 3770 first module. 3771ERST 3772 3773DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3774 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3775SRST 3776``-dtb file`` 3777 Use file as a device tree binary (dtb) image and pass it to the 3778 kernel on boot. 3779ERST 3780 3781DEFHEADING() 3782 3783DEFHEADING(Debug/Expert options:) 3784 3785DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3786 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3787 " Policy for handling deprecated management interfaces\n" 3788 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3789 " Policy for handling unstable management interfaces\n", 3790 QEMU_ARCH_ALL) 3791SRST 3792``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3793 Set policy for handling deprecated management interfaces (experimental): 3794 3795 ``deprecated-input=accept`` (default) 3796 Accept deprecated commands and arguments 3797 ``deprecated-input=reject`` 3798 Reject deprecated commands and arguments 3799 ``deprecated-input=crash`` 3800 Crash on deprecated commands and arguments 3801 ``deprecated-output=accept`` (default) 3802 Emit deprecated command results and events 3803 ``deprecated-output=hide`` 3804 Suppress deprecated command results and events 3805 3806 Limitation: covers only syntactic aspects of QMP. 3807 3808``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3809 Set policy for handling unstable management interfaces (experimental): 3810 3811 ``unstable-input=accept`` (default) 3812 Accept unstable commands and arguments 3813 ``unstable-input=reject`` 3814 Reject unstable commands and arguments 3815 ``unstable-input=crash`` 3816 Crash on unstable commands and arguments 3817 ``unstable-output=accept`` (default) 3818 Emit unstable command results and events 3819 ``unstable-output=hide`` 3820 Suppress unstable command results and events 3821 3822 Limitation: covers only syntactic aspects of QMP. 3823ERST 3824 3825DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3826 "-fw_cfg [name=]<name>,file=<file>\n" 3827 " add named fw_cfg entry with contents from file\n" 3828 "-fw_cfg [name=]<name>,string=<str>\n" 3829 " add named fw_cfg entry with contents from string\n", 3830 QEMU_ARCH_ALL) 3831SRST 3832``-fw_cfg [name=]name,file=file`` 3833 Add named fw\_cfg entry with contents from file file. 3834 3835``-fw_cfg [name=]name,string=str`` 3836 Add named fw\_cfg entry with contents from string str. 3837 3838 The terminating NUL character of the contents of str will not be 3839 included as part of the fw\_cfg item data. To insert contents with 3840 embedded NUL characters, you have to use the file parameter. 3841 3842 The fw\_cfg entries are passed by QEMU through to the guest. 3843 3844 Example: 3845 3846 :: 3847 3848 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3849 3850 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3851 from ./my\_blob.bin. 3852ERST 3853 3854DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3855 "-serial dev redirect the serial port to char device 'dev'\n", 3856 QEMU_ARCH_ALL) 3857SRST 3858``-serial dev`` 3859 Redirect the virtual serial port to host character device dev. The 3860 default device is ``vc`` in graphical mode and ``stdio`` in non 3861 graphical mode. 3862 3863 This option can be used several times to simulate up to 4 serial 3864 ports. 3865 3866 Use ``-serial none`` to disable all serial ports. 3867 3868 Available character devices are: 3869 3870 ``vc[:WxH]`` 3871 Virtual console. Optionally, a width and height can be given in 3872 pixel with 3873 3874 :: 3875 3876 vc:800x600 3877 3878 It is also possible to specify width or height in characters: 3879 3880 :: 3881 3882 vc:80Cx24C 3883 3884 ``pty`` 3885 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3886 3887 ``none`` 3888 No device is allocated. 3889 3890 ``null`` 3891 void device 3892 3893 ``chardev:id`` 3894 Use a named character device defined with the ``-chardev`` 3895 option. 3896 3897 ``/dev/XXX`` 3898 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3899 port parameters are set according to the emulated ones. 3900 3901 ``/dev/parportN`` 3902 [Linux only, parallel port only] Use host parallel port N. 3903 Currently SPP and EPP parallel port features can be used. 3904 3905 ``file:filename`` 3906 Write output to filename. No character can be read. 3907 3908 ``stdio`` 3909 [Unix only] standard input/output 3910 3911 ``pipe:filename`` 3912 name pipe filename 3913 3914 ``COMn`` 3915 [Windows only] Use host serial port n 3916 3917 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3918 This implements UDP Net Console. When remote\_host or src\_ip 3919 are not specified they default to ``0.0.0.0``. When not using a 3920 specified src\_port a random port is automatically chosen. 3921 3922 If you just want a simple readonly console you can use 3923 ``netcat`` or ``nc``, by starting QEMU with: 3924 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3925 QEMU writes something to that port it will appear in the 3926 netconsole session. 3927 3928 If you plan to send characters back via netconsole or you want 3929 to stop and start QEMU a lot of times, you should have QEMU use 3930 the same source port each time by using something like ``-serial 3931 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3932 version of netcat which can listen to a TCP port and send and 3933 receive characters via udp. If you have a patched version of 3934 netcat which activates telnet remote echo and single char 3935 transfer, then you can use the following options to set up a 3936 netcat redirector to allow telnet on port 5555 to access the 3937 QEMU port. 3938 3939 ``QEMU Options:`` 3940 -serial udp::4555@:4556 3941 3942 ``netcat options:`` 3943 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3944 3945 ``telnet options:`` 3946 localhost 5555 3947 3948 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3949 The TCP Net Console has two modes of operation. It can send the 3950 serial I/O to a location or wait for a connection from a 3951 location. By default the TCP Net Console is sent to host at the 3952 port. If you use the ``server=on`` option QEMU will wait for a client 3953 socket application to connect to the port before continuing, 3954 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3955 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3956 option only applies if ``server=no`` is set, if the connection goes 3957 down it will attempt to reconnect at the given interval. If host 3958 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3959 time is accepted. You can use ``telnet=on`` to connect to the 3960 corresponding character device. 3961 3962 ``Example to send tcp console to 192.168.0.2 port 4444`` 3963 -serial tcp:192.168.0.2:4444 3964 3965 ``Example to listen and wait on port 4444 for connection`` 3966 -serial tcp::4444,server=on 3967 3968 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3969 -serial tcp:192.168.0.100:4444,server=on,wait=off 3970 3971 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3972 The telnet protocol is used instead of raw tcp sockets. The 3973 options work the same as if you had specified ``-serial tcp``. 3974 The difference is that the port acts like a telnet server or 3975 client using telnet option negotiation. This will also allow you 3976 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3977 supports sending the break sequence. Typically in unix telnet 3978 you do it with Control-] and then type "send break" followed by 3979 pressing the enter key. 3980 3981 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3982 The WebSocket protocol is used instead of raw tcp socket. The 3983 port acts as a WebSocket server. Client mode is not supported. 3984 3985 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3986 A unix domain socket is used instead of a tcp socket. The option 3987 works the same as if you had specified ``-serial tcp`` except 3988 the unix domain socket path is used for connections. 3989 3990 ``mon:dev_string`` 3991 This is a special option to allow the monitor to be multiplexed 3992 onto another serial port. The monitor is accessed with key 3993 sequence of Control-a and then pressing c. dev\_string should be 3994 any one of the serial devices specified above. An example to 3995 multiplex the monitor onto a telnet server listening on port 3996 4444 would be: 3997 3998 ``-serial mon:telnet::4444,server=on,wait=off`` 3999 4000 When the monitor is multiplexed to stdio in this way, Ctrl+C 4001 will not terminate QEMU any more but will be passed to the guest 4002 instead. 4003 4004 ``braille`` 4005 Braille device. This will use BrlAPI to display the braille 4006 output on a real or fake device. 4007 4008 ``msmouse`` 4009 Three button serial mouse. Configure the guest to use Microsoft 4010 protocol. 4011ERST 4012 4013DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4014 "-parallel dev redirect the parallel port to char device 'dev'\n", 4015 QEMU_ARCH_ALL) 4016SRST 4017``-parallel dev`` 4018 Redirect the virtual parallel port to host device dev (same devices 4019 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4020 to use hardware devices connected on the corresponding host parallel 4021 port. 4022 4023 This option can be used several times to simulate up to 3 parallel 4024 ports. 4025 4026 Use ``-parallel none`` to disable all parallel ports. 4027ERST 4028 4029DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4030 "-monitor dev redirect the monitor to char device 'dev'\n", 4031 QEMU_ARCH_ALL) 4032SRST 4033``-monitor dev`` 4034 Redirect the monitor to host device dev (same devices as the serial 4035 port). The default device is ``vc`` in graphical mode and ``stdio`` 4036 in non graphical mode. Use ``-monitor none`` to disable the default 4037 monitor. 4038ERST 4039DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4040 "-qmp dev like -monitor but opens in 'control' mode\n", 4041 QEMU_ARCH_ALL) 4042SRST 4043``-qmp dev`` 4044 Like -monitor but opens in 'control' mode. 4045ERST 4046DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4047 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4048 QEMU_ARCH_ALL) 4049SRST 4050``-qmp-pretty dev`` 4051 Like -qmp but uses pretty JSON formatting. 4052ERST 4053 4054DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4055 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4056SRST 4057``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4058 Setup monitor on chardev name. ``mode=control`` configures 4059 a QMP monitor (a JSON RPC-style protocol) and it is not the 4060 same as HMP, the human monitor that has a "(qemu)" prompt. 4061 ``pretty`` is only valid when ``mode=control``, 4062 turning on JSON pretty printing to ease 4063 human reading and debugging. 4064ERST 4065 4066DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4067 "-debugcon dev redirect the debug console to char device 'dev'\n", 4068 QEMU_ARCH_ALL) 4069SRST 4070``-debugcon dev`` 4071 Redirect the debug console to host device dev (same devices as the 4072 serial port). The debug console is an I/O port which is typically 4073 port 0xe9; writing to that I/O port sends output to this device. The 4074 default device is ``vc`` in graphical mode and ``stdio`` in non 4075 graphical mode. 4076ERST 4077 4078DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4079 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4080SRST 4081``-pidfile file`` 4082 Store the QEMU process PID in file. It is useful if you launch QEMU 4083 from a script. 4084ERST 4085 4086DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4087 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4088SRST 4089``-singlestep`` 4090 Run the emulation in single step mode. 4091ERST 4092 4093DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4094 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4095 QEMU_ARCH_ALL) 4096SRST 4097``--preconfig`` 4098 Pause QEMU for interactive configuration before the machine is 4099 created, which allows querying and configuring properties that will 4100 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4101 exit the preconfig state and move to the next state (i.e. run guest 4102 if -S isn't used or pause the second time if -S is used). This 4103 option is experimental. 4104ERST 4105 4106DEF("S", 0, QEMU_OPTION_S, \ 4107 "-S freeze CPU at startup (use 'c' to start execution)\n", 4108 QEMU_ARCH_ALL) 4109SRST 4110``-S`` 4111 Do not start CPU at startup (you must type 'c' in the monitor). 4112ERST 4113 4114DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4115 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4116 " run qemu with overcommit hints\n" 4117 " mem-lock=on|off controls memory lock support (default: off)\n" 4118 " cpu-pm=on|off controls cpu power management (default: off)\n", 4119 QEMU_ARCH_ALL) 4120SRST 4121``-overcommit mem-lock=on|off`` 4122 \ 4123``-overcommit cpu-pm=on|off`` 4124 Run qemu with hints about host resource overcommit. The default is 4125 to assume that host overcommits all resources. 4126 4127 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4128 (disabled by default). This works when host memory is not 4129 overcommitted and reduces the worst-case latency for guest. 4130 4131 Guest ability to manage power state of host cpus (increasing latency 4132 for other processes on the same host cpu, but decreasing latency for 4133 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4134 works best when host CPU is not overcommitted. When used, host 4135 estimates of CPU cycle and power utilization will be incorrect, not 4136 taking into account guest idle time. 4137ERST 4138 4139DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4140 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4141 " the guest without waiting for gdb to connect; use -S too\n" 4142 " if you want it to not start execution.)\n", 4143 QEMU_ARCH_ALL) 4144SRST 4145``-gdb dev`` 4146 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4147 in the System Emulation Users Guide). Note that this option does not pause QEMU 4148 execution -- if you want QEMU to not start the guest until you 4149 connect with gdb and issue a ``continue`` command, you will need to 4150 also pass the ``-S`` option to QEMU. 4151 4152 The most usual configuration is to listen on a local TCP socket:: 4153 4154 -gdb tcp::3117 4155 4156 but you can specify other backends; UDP, pseudo TTY, or even stdio 4157 are all reasonable use cases. For example, a stdio connection 4158 allows you to start QEMU from within gdb and establish the 4159 connection via a pipe: 4160 4161 .. parsed-literal:: 4162 4163 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4164ERST 4165 4166DEF("s", 0, QEMU_OPTION_s, \ 4167 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4168 QEMU_ARCH_ALL) 4169SRST 4170``-s`` 4171 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4172 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4173ERST 4174 4175DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4176 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4177 QEMU_ARCH_ALL) 4178SRST 4179``-d item1[,...]`` 4180 Enable logging of specified items. Use '-d help' for a list of log 4181 items. 4182ERST 4183 4184DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4185 "-D logfile output log to logfile (default stderr)\n", 4186 QEMU_ARCH_ALL) 4187SRST 4188``-D logfile`` 4189 Output log in logfile instead of to stderr 4190ERST 4191 4192DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4193 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4194 QEMU_ARCH_ALL) 4195SRST 4196``-dfilter range1[,...]`` 4197 Filter debug output to that relevant to a range of target addresses. 4198 The filter spec can be either start+size, start-size or start..end 4199 where start end and size are the addresses and sizes required. For 4200 example: 4201 4202 :: 4203 4204 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4205 4206 Will dump output for any code in the 0x1000 sized block starting at 4207 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4208 another 0x1000 sized block starting at 0xffffffc00005f000. 4209ERST 4210 4211DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4212 "-seed number seed the pseudo-random number generator\n", 4213 QEMU_ARCH_ALL) 4214SRST 4215``-seed number`` 4216 Force the guest to use a deterministic pseudo-random number 4217 generator, seeded with number. This does not affect crypto routines 4218 within the host. 4219ERST 4220 4221DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4222 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4223 QEMU_ARCH_ALL) 4224SRST 4225``-L path`` 4226 Set the directory for the BIOS, VGA BIOS and keymaps. 4227 4228 To list all the data directories, use ``-L help``. 4229ERST 4230 4231DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4232 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4233SRST 4234``-bios file`` 4235 Set the filename for the BIOS. 4236ERST 4237 4238DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4239 "-enable-kvm enable KVM full virtualization support\n", 4240 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4241 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4242SRST 4243``-enable-kvm`` 4244 Enable KVM full virtualization support. This option is only 4245 available if KVM support is enabled when compiling. 4246ERST 4247 4248DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4249 "-xen-domid id specify xen guest domain id\n", 4250 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4251DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4252 "-xen-attach attach to existing xen domain\n" 4253 " libxl will use this when starting QEMU\n", 4254 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4255DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4256 "-xen-domid-restrict restrict set of available xen operations\n" 4257 " to specified domain id. (Does not affect\n" 4258 " xenpv machine type).\n", 4259 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4260SRST 4261``-xen-domid id`` 4262 Specify xen guest domain id (XEN only). 4263 4264``-xen-attach`` 4265 Attach to existing xen domain. libxl will use this when starting 4266 QEMU (XEN only). Restrict set of available xen operations to 4267 specified domain id (XEN only). 4268ERST 4269 4270DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4271 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4272SRST 4273``-no-reboot`` 4274 Exit instead of rebooting. 4275ERST 4276 4277DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4278 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4279SRST 4280``-no-shutdown`` 4281 Don't exit QEMU on guest shutdown, but instead only stop the 4282 emulation. This allows for instance switching to monitor to commit 4283 changes to the disk image. 4284ERST 4285 4286DEF("action", HAS_ARG, QEMU_OPTION_action, 4287 "-action reboot=reset|shutdown\n" 4288 " action when guest reboots [default=reset]\n" 4289 "-action shutdown=poweroff|pause\n" 4290 " action when guest shuts down [default=poweroff]\n" 4291 "-action panic=pause|shutdown|none\n" 4292 " action when guest panics [default=shutdown]\n" 4293 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4294 " action when watchdog fires [default=reset]\n", 4295 QEMU_ARCH_ALL) 4296SRST 4297``-action event=action`` 4298 The action parameter serves to modify QEMU's default behavior when 4299 certain guest events occur. It provides a generic method for specifying the 4300 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4301 parameters. 4302 4303 Examples: 4304 4305 ``-action panic=none`` 4306 ``-action reboot=shutdown,shutdown=pause`` 4307 ``-watchdog i6300esb -action watchdog=pause`` 4308 4309ERST 4310 4311DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4312 "-loadvm [tag|id]\n" \ 4313 " start right away with a saved state (loadvm in monitor)\n", 4314 QEMU_ARCH_ALL) 4315SRST 4316``-loadvm file`` 4317 Start right away with a saved state (``loadvm`` in monitor) 4318ERST 4319 4320#ifndef _WIN32 4321DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4322 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4323#endif 4324SRST 4325``-daemonize`` 4326 Daemonize the QEMU process after initialization. QEMU will not 4327 detach from standard IO until it is ready to receive connections on 4328 any of its devices. This option is a useful way for external 4329 programs to launch QEMU without having to cope with initialization 4330 race conditions. 4331ERST 4332 4333DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4334 "-option-rom rom load a file, rom, into the option ROM space\n", 4335 QEMU_ARCH_ALL) 4336SRST 4337``-option-rom file`` 4338 Load the contents of file as an option ROM. This option is useful to 4339 load things like EtherBoot. 4340ERST 4341 4342DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4343 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4344 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4345 QEMU_ARCH_ALL) 4346 4347SRST 4348``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4349 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4350 the current UTC or local time, respectively. ``localtime`` is 4351 required for correct date in MS-DOS or Windows. To start at a 4352 specific point in time, provide datetime in the format 4353 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4354 4355 By default the RTC is driven by the host system time. This allows 4356 using of the RTC as accurate reference clock inside the guest, 4357 specifically if the host time is smoothly following an accurate 4358 external reference clock, e.g. via NTP. If you want to isolate the 4359 guest time from the host, you can set ``clock`` to ``rt`` instead, 4360 which provides a host monotonic clock if host support it. To even 4361 prevent the RTC from progressing during suspension, you can set 4362 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4363 recommended especially in icount mode in order to preserve 4364 determinism; however, note that in icount mode the speed of the 4365 virtual clock is variable and can in general differ from the host 4366 clock. 4367 4368 Enable ``driftfix`` (i386 targets only) if you experience time drift 4369 problems, specifically with Windows' ACPI HAL. This option will try 4370 to figure out how many timer interrupts were not processed by the 4371 Windows guest and will re-inject them. 4372ERST 4373 4374DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4375 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4376 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4377 " instruction, enable aligning the host and virtual clocks\n" \ 4378 " or disable real time cpu sleeping, and optionally enable\n" \ 4379 " record-and-replay mode\n", QEMU_ARCH_ALL) 4380SRST 4381``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4382 Enable virtual instruction counter. The virtual cpu will execute one 4383 instruction every 2^N ns of virtual time. If ``auto`` is specified 4384 then the virtual cpu speed will be automatically adjusted to keep 4385 virtual time within a few seconds of real time. 4386 4387 Note that while this option can give deterministic behavior, it does 4388 not provide cycle accurate emulation. Modern CPUs contain 4389 superscalar out of order cores with complex cache hierarchies. The 4390 number of instructions executed often has little or no correlation 4391 with actual performance. 4392 4393 When the virtual cpu is sleeping, the virtual time will advance at 4394 default speed unless ``sleep=on`` is specified. With 4395 ``sleep=on``, the virtual time will jump to the next timer 4396 deadline instantly whenever the virtual cpu goes to sleep mode and 4397 will not advance if no timer is enabled. This behavior gives 4398 deterministic execution times from the guest point of view. 4399 The default if icount is enabled is ``sleep=off``. 4400 ``sleep=on`` cannot be used together with either ``shift=auto`` 4401 or ``align=on``. 4402 4403 ``align=on`` will activate the delay algorithm which will try to 4404 synchronise the host clock and the virtual clock. The goal is to 4405 have a guest running at the real frequency imposed by the shift 4406 option. Whenever the guest clock is behind the host clock and if 4407 ``align=on`` is specified then we print a message to the user to 4408 inform about the delay. Currently this option does not work when 4409 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4410 shift values for which the guest clock runs ahead of the host clock. 4411 Typically this happens when the shift value is high (how high 4412 depends on the host machine). The default if icount is enabled 4413 is ``align=off``. 4414 4415 When the ``rr`` option is specified deterministic record/replay is 4416 enabled. The ``rrfile=`` option must also be provided to 4417 specify the path to the replay log. In record mode data is written 4418 to this file, and in replay mode it is read back. 4419 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4420 name. In record mode, a new VM snapshot with the given name is created 4421 at the start of execution recording. In replay mode this option 4422 specifies the snapshot name used to load the initial VM state. 4423ERST 4424 4425DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4426 "-watchdog model\n" \ 4427 " enable virtual hardware watchdog [default=none]\n", 4428 QEMU_ARCH_ALL) 4429SRST 4430``-watchdog model`` 4431 Create a virtual hardware watchdog device. Once enabled (by a guest 4432 action), the watchdog must be periodically polled by an agent inside 4433 the guest or else the guest will be restarted. Choose a model for 4434 which your guest has drivers. 4435 4436 The model is the model of hardware watchdog to emulate. Use 4437 ``-watchdog help`` to list available hardware models. Only one 4438 watchdog can be enabled for a guest. 4439 4440 The following models may be available: 4441 4442 ``ib700`` 4443 iBASE 700 is a very simple ISA watchdog with a single timer. 4444 4445 ``i6300esb`` 4446 Intel 6300ESB I/O controller hub is a much more featureful 4447 PCI-based dual-timer watchdog. 4448 4449 ``diag288`` 4450 A virtual watchdog for s390x backed by the diagnose 288 4451 hypercall (currently KVM only). 4452ERST 4453 4454DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4455 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4456 " action when watchdog fires [default=reset]\n", 4457 QEMU_ARCH_ALL) 4458SRST 4459``-watchdog-action action`` 4460 The action controls what QEMU will do when the watchdog timer 4461 expires. The default is ``reset`` (forcefully reset the guest). 4462 Other possible actions are: ``shutdown`` (attempt to gracefully 4463 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4464 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4465 guest), ``debug`` (print a debug message and continue), or ``none`` 4466 (do nothing). 4467 4468 Note that the ``shutdown`` action requires that the guest responds 4469 to ACPI signals, which it may not be able to do in the sort of 4470 situations where the watchdog would have expired, and thus 4471 ``-watchdog-action shutdown`` is not recommended for production use. 4472 4473 Examples: 4474 4475 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4476 4477ERST 4478 4479DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4480 "-echr chr set terminal escape character instead of ctrl-a\n", 4481 QEMU_ARCH_ALL) 4482SRST 4483``-echr numeric_ascii_value`` 4484 Change the escape character used for switching to the monitor when 4485 using monitor and serial sharing. The default is ``0x01`` when using 4486 the ``-nographic`` option. ``0x01`` is equal to pressing 4487 ``Control-a``. You can select a different character from the ascii 4488 control keys where 1 through 26 map to Control-a through Control-z. 4489 For instance you could use the either of the following to change the 4490 escape character to Control-t. 4491 4492 ``-echr 0x14``; \ ``-echr 20`` 4493 4494ERST 4495 4496DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4497 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4498 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4499 "-incoming unix:socketpath\n" \ 4500 " prepare for incoming migration, listen on\n" \ 4501 " specified protocol and socket address\n" \ 4502 "-incoming fd:fd\n" \ 4503 "-incoming exec:cmdline\n" \ 4504 " accept incoming migration on given file descriptor\n" \ 4505 " or from given external command\n" \ 4506 "-incoming defer\n" \ 4507 " wait for the URI to be specified via migrate_incoming\n", 4508 QEMU_ARCH_ALL) 4509SRST 4510``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4511 \ 4512``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4513 Prepare for incoming migration, listen on a given tcp port. 4514 4515``-incoming unix:socketpath`` 4516 Prepare for incoming migration, listen on a given unix socket. 4517 4518``-incoming fd:fd`` 4519 Accept incoming migration from a given filedescriptor. 4520 4521``-incoming exec:cmdline`` 4522 Accept incoming migration as an output from specified external 4523 command. 4524 4525``-incoming defer`` 4526 Wait for the URI to be specified via migrate\_incoming. The monitor 4527 can be used to change settings (such as migration parameters) prior 4528 to issuing the migrate\_incoming to allow the migration to begin. 4529ERST 4530 4531DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4532 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4533SRST 4534``-only-migratable`` 4535 Only allow migratable devices. Devices will not be allowed to enter 4536 an unmigratable state. 4537ERST 4538 4539DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4540 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4541SRST 4542``-nodefaults`` 4543 Don't create default devices. Normally, QEMU sets the default 4544 devices like serial port, parallel port, virtual console, monitor 4545 device, VGA adapter, floppy and CD-ROM drive and others. The 4546 ``-nodefaults`` option will disable all those default devices. 4547ERST 4548 4549#ifndef _WIN32 4550DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4551 "-chroot dir chroot to dir just before starting the VM\n", 4552 QEMU_ARCH_ALL) 4553#endif 4554SRST 4555``-chroot dir`` 4556 Immediately before starting guest execution, chroot to the specified 4557 directory. Especially useful in combination with -runas. 4558ERST 4559 4560#ifndef _WIN32 4561DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4562 "-runas user change to user id user just before starting the VM\n" \ 4563 " user can be numeric uid:gid instead\n", 4564 QEMU_ARCH_ALL) 4565#endif 4566SRST 4567``-runas user`` 4568 Immediately before starting guest execution, drop root privileges, 4569 switching to the specified user. 4570ERST 4571 4572DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4573 "-prom-env variable=value\n" 4574 " set OpenBIOS nvram variables\n", 4575 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4576SRST 4577``-prom-env variable=value`` 4578 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4579 4580 :: 4581 4582 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4583 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4584 4585 :: 4586 4587 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4588 -prom-env 'boot-device=hd:2,\yaboot' \ 4589 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4590ERST 4591DEF("semihosting", 0, QEMU_OPTION_semihosting, 4592 "-semihosting semihosting mode\n", 4593 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4594 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4595SRST 4596``-semihosting`` 4597 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4598 4599 Note that this allows guest direct access to the host filesystem, so 4600 should only be used with a trusted guest OS. 4601 4602 See the -semihosting-config option documentation for further 4603 information about the facilities this enables. 4604ERST 4605DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4606 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4607 " semihosting configuration\n", 4608QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4609QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4610SRST 4611``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4612 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4613 only). 4614 4615 Note that this allows guest direct access to the host filesystem, so 4616 should only be used with a trusted guest OS. 4617 4618 On Arm this implements the standard semihosting API, version 2.0. 4619 4620 On M68K this implements the "ColdFire GDB" interface used by 4621 libgloss. 4622 4623 Xtensa semihosting provides basic file IO calls, such as 4624 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4625 linux platform "sim" use this interface. 4626 4627 On RISC-V this implements the standard semihosting API, version 0.2. 4628 4629 ``target=native|gdb|auto`` 4630 Defines where the semihosting calls will be addressed, to QEMU 4631 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4632 means ``gdb`` during debug sessions and ``native`` otherwise. 4633 4634 ``chardev=str1`` 4635 Send the output to a chardev backend output for native or auto 4636 output when not in gdb 4637 4638 ``arg=str1,arg=str2,...`` 4639 Allows the user to pass input arguments, and can be used 4640 multiple times to build up a list. The old-style 4641 ``-kernel``/``-append`` method of passing a command line is 4642 still supported for backward compatibility. If both the 4643 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4644 specified, the former is passed to semihosting as it always 4645 takes precedence. 4646ERST 4647DEF("old-param", 0, QEMU_OPTION_old_param, 4648 "-old-param old param mode\n", QEMU_ARCH_ARM) 4649SRST 4650``-old-param`` 4651 Old param mode (ARM only). 4652ERST 4653 4654DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4655 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4656 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4657 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4658 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4659 " by the kernel, but typically no longer used by modern\n" \ 4660 " C library implementations.\n" \ 4661 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4662 " to elevate privileges using set*uid|gid system calls.\n" \ 4663 " The value 'children' will deny set*uid|gid system calls for\n" \ 4664 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4665 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4666 " blocking *fork and execve\n" \ 4667 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4668 QEMU_ARCH_ALL) 4669SRST 4670``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4671 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4672 filtering and 'off' will disable it. The default is 'off'. 4673 4674 ``obsolete=string`` 4675 Enable Obsolete system calls 4676 4677 ``elevateprivileges=string`` 4678 Disable set\*uid\|gid system calls 4679 4680 ``spawn=string`` 4681 Disable \*fork and execve 4682 4683 ``resourcecontrol=string`` 4684 Disable process affinity and schedular priority 4685ERST 4686 4687DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4688 "-readconfig <file>\n" 4689 " read config file\n", QEMU_ARCH_ALL) 4690SRST 4691``-readconfig file`` 4692 Read device configuration from file. This approach is useful when 4693 you want to spawn QEMU process with many command line options but 4694 you don't want to exceed the command line character limit. 4695ERST 4696 4697DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4698 "-no-user-config\n" 4699 " do not load default user-provided config files at startup\n", 4700 QEMU_ARCH_ALL) 4701SRST 4702``-no-user-config`` 4703 The ``-no-user-config`` option makes QEMU not load any of the 4704 user-provided config files on sysconfdir. 4705ERST 4706 4707DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4708 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4709 " specify tracing options\n", 4710 QEMU_ARCH_ALL) 4711SRST 4712``-trace [[enable=]pattern][,events=file][,file=file]`` 4713 .. include:: ../qemu-option-trace.rst.inc 4714 4715ERST 4716DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4717 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4718 " load a plugin\n", 4719 QEMU_ARCH_ALL) 4720SRST 4721``-plugin file=file[,argname=argvalue]`` 4722 Load a plugin. 4723 4724 ``file=file`` 4725 Load the given plugin from a shared library file. 4726 4727 ``argname=argvalue`` 4728 Argument passed to the plugin. (Can be given multiple times.) 4729ERST 4730 4731HXCOMM Internal use 4732DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4733DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4734 4735DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4736 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4737 " control error message format\n" 4738 " timestamp=on enables timestamps (default: off)\n" 4739 " guest-name=on enables guest name prefix but only if\n" 4740 " -name guest option is set (default: off)\n", 4741 QEMU_ARCH_ALL) 4742SRST 4743``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4744 Control error message format. 4745 4746 ``timestamp=on|off`` 4747 Prefix messages with a timestamp. Default is off. 4748 4749 ``guest-name=on|off`` 4750 Prefix messages with guest name but only if -name guest option is set 4751 otherwise the option is ignored. Default is off. 4752ERST 4753 4754DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4755 "-dump-vmstate <file>\n" 4756 " Output vmstate information in JSON format to file.\n" 4757 " Use the scripts/vmstate-static-checker.py file to\n" 4758 " check for possible regressions in migration code\n" 4759 " by comparing two such vmstate dumps.\n", 4760 QEMU_ARCH_ALL) 4761SRST 4762``-dump-vmstate file`` 4763 Dump json-encoded vmstate information for current machine type to 4764 file in file 4765ERST 4766 4767DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4768 "-enable-sync-profile\n" 4769 " enable synchronization profiling\n", 4770 QEMU_ARCH_ALL) 4771SRST 4772``-enable-sync-profile`` 4773 Enable synchronization profiling. 4774ERST 4775 4776DEFHEADING() 4777 4778DEFHEADING(Generic object creation:) 4779 4780DEF("object", HAS_ARG, QEMU_OPTION_object, 4781 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4782 " create a new object of type TYPENAME setting properties\n" 4783 " in the order they are specified. Note that the 'id'\n" 4784 " property must be set. These objects are placed in the\n" 4785 " '/objects' path.\n", 4786 QEMU_ARCH_ALL) 4787SRST 4788``-object typename[,prop1=value1,...]`` 4789 Create a new object of type typename setting properties in the order 4790 they are specified. Note that the 'id' property must be set. These 4791 objects are placed in the '/objects' path. 4792 4793 ``-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`` 4794 Creates a memory file backend object, which can be used to back 4795 the guest RAM with huge pages. 4796 4797 The ``id`` parameter is a unique ID that will be used to 4798 reference this memory region in other parameters, e.g. ``-numa``, 4799 ``-device nvdimm``, etc. 4800 4801 The ``size`` option provides the size of the memory region, and 4802 accepts common suffixes, e.g. ``500M``. 4803 4804 The ``mem-path`` provides the path to either a shared memory or 4805 huge page filesystem mount. 4806 4807 The ``share`` boolean option determines whether the memory 4808 region is marked as private to QEMU, or shared. The latter 4809 allows a co-operating external process to access the QEMU memory 4810 region. 4811 4812 The ``share`` is also required for pvrdma devices due to 4813 limitations in the RDMA API provided by Linux. 4814 4815 Setting share=on might affect the ability to configure NUMA 4816 bindings for the memory backend under some circumstances, see 4817 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4818 source tree for additional details. 4819 4820 Setting the ``discard-data`` boolean option to on indicates that 4821 file contents can be destroyed when QEMU exits, to avoid 4822 unnecessarily flushing data to the backing file. Note that 4823 ``discard-data`` is only an optimization, and QEMU might not 4824 discard file contents if it aborts unexpectedly or is terminated 4825 using SIGKILL. 4826 4827 The ``merge`` boolean option enables memory merge, also known as 4828 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4829 the pages for memory deduplication. 4830 4831 Setting the ``dump`` boolean option to off excludes the memory 4832 from core dumps. This feature is also known as MADV\_DONTDUMP. 4833 4834 The ``prealloc`` boolean option enables memory preallocation. 4835 4836 The ``host-nodes`` option binds the memory range to a list of 4837 NUMA host nodes. 4838 4839 The ``policy`` option sets the NUMA policy to one of the 4840 following values: 4841 4842 ``default`` 4843 default host policy 4844 4845 ``preferred`` 4846 prefer the given host node list for allocation 4847 4848 ``bind`` 4849 restrict memory allocation to the given host node list 4850 4851 ``interleave`` 4852 interleave memory allocations across the given host node 4853 list 4854 4855 The ``align`` option specifies the base address alignment when 4856 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4857 ``2M``. Some backend store specified by ``mem-path`` requires an 4858 alignment different than the default one used by QEMU, eg the 4859 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4860 such cases, users can specify the required alignment via this 4861 option. 4862 4863 The ``pmem`` option specifies whether the backing file specified 4864 by ``mem-path`` is in host persistent memory that can be 4865 accessed using the SNIA NVM programming model (e.g. Intel 4866 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4867 operations to guarantee the persistence of its own writes to 4868 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4869 migration). Also, we will map the backend-file with MAP\_SYNC 4870 flag, which ensures the file metadata is in sync for 4871 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4872 requires support from both the host kernel (since Linux kernel 4873 4.15) and the filesystem of ``mem-path`` mounted with DAX 4874 option. 4875 4876 The ``readonly`` option specifies whether the backing file is opened 4877 read-only or read-write (default). 4878 4879 ``-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`` 4880 Creates a memory backend object, which can be used to back the 4881 guest RAM. Memory backend objects offer more control than the 4882 ``-m`` option that is traditionally used to define guest RAM. 4883 Please refer to ``memory-backend-file`` for a description of the 4884 options. 4885 4886 ``-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`` 4887 Creates an anonymous memory file backend object, which allows 4888 QEMU to share the memory with an external process (e.g. when 4889 using vhost-user). The memory is allocated with memfd and 4890 optional sealing. (Linux only) 4891 4892 The ``seal`` option creates a sealed-file, that will block 4893 further resizing the memory ('on' by default). 4894 4895 The ``hugetlb`` option specify the file to be created resides in 4896 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4897 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4898 the hugetlb page size on systems that support multiple hugetlb 4899 page sizes (it must be a power of 2 value supported by the 4900 system). 4901 4902 In some versions of Linux, the ``hugetlb`` option is 4903 incompatible with the ``seal`` option (requires at least Linux 4904 4.16). 4905 4906 Please refer to ``memory-backend-file`` for a description of the 4907 other options. 4908 4909 The ``share`` boolean option is on by default with memfd. 4910 4911 ``-object rng-builtin,id=id`` 4912 Creates a random number generator backend which obtains entropy 4913 from QEMU builtin functions. The ``id`` parameter is a unique ID 4914 that will be used to reference this entropy backend from the 4915 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4916 uses this RNG backend. 4917 4918 ``-object rng-random,id=id,filename=/dev/random`` 4919 Creates a random number generator backend which obtains entropy 4920 from a device on the host. The ``id`` parameter is a unique ID 4921 that will be used to reference this entropy backend from the 4922 ``virtio-rng`` device. The ``filename`` parameter specifies 4923 which file to obtain entropy from and if omitted defaults to 4924 ``/dev/urandom``. 4925 4926 ``-object rng-egd,id=id,chardev=chardevid`` 4927 Creates a random number generator backend which obtains entropy 4928 from an external daemon running on the host. The ``id`` 4929 parameter is a unique ID that will be used to reference this 4930 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4931 parameter is the unique ID of a character device backend that 4932 provides the connection to the RNG daemon. 4933 4934 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4935 Creates a TLS anonymous credentials object, which can be used to 4936 provide TLS support on network backends. The ``id`` parameter is 4937 a unique ID which network backends will use to access the 4938 credentials. The ``endpoint`` is either ``server`` or ``client`` 4939 depending on whether the QEMU network backend that uses the 4940 credentials will be acting as a client or as a server. If 4941 ``verify-peer`` is enabled (the default) then once the handshake 4942 is completed, the peer credentials will be verified, though this 4943 is a no-op for anonymous credentials. 4944 4945 The dir parameter tells QEMU where to find the credential files. 4946 For server endpoints, this directory may contain a file 4947 dh-params.pem providing diffie-hellman parameters to use for the 4948 TLS server. If the file is missing, QEMU will generate a set of 4949 DH parameters at startup. This is a computationally expensive 4950 operation that consumes random pool entropy, so it is 4951 recommended that a persistent set of parameters be generated 4952 upfront and saved. 4953 4954 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4955 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4956 can be used to provide TLS support on network backends. The 4957 ``id`` parameter is a unique ID which network backends will use 4958 to access the credentials. The ``endpoint`` is either ``server`` 4959 or ``client`` depending on whether the QEMU network backend that 4960 uses the credentials will be acting as a client or as a server. 4961 For clients only, ``username`` is the username which will be 4962 sent to the server. If omitted it defaults to "qemu". 4963 4964 The dir parameter tells QEMU where to find the keys file. It is 4965 called "dir/keys.psk" and contains "username:key" pairs. This 4966 file can most easily be created using the GnuTLS ``psktool`` 4967 program. 4968 4969 For server endpoints, dir may also contain a file dh-params.pem 4970 providing diffie-hellman parameters to use for the TLS server. 4971 If the file is missing, QEMU will generate a set of DH 4972 parameters at startup. This is a computationally expensive 4973 operation that consumes random pool entropy, so it is 4974 recommended that a persistent set of parameters be generated up 4975 front and saved. 4976 4977 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4978 Creates a TLS anonymous credentials object, which can be used to 4979 provide TLS support on network backends. The ``id`` parameter is 4980 a unique ID which network backends will use to access the 4981 credentials. The ``endpoint`` is either ``server`` or ``client`` 4982 depending on whether the QEMU network backend that uses the 4983 credentials will be acting as a client or as a server. If 4984 ``verify-peer`` is enabled (the default) then once the handshake 4985 is completed, the peer credentials will be verified. With x509 4986 certificates, this implies that the clients must be provided 4987 with valid client certificates too. 4988 4989 The dir parameter tells QEMU where to find the credential files. 4990 For server endpoints, this directory may contain a file 4991 dh-params.pem providing diffie-hellman parameters to use for the 4992 TLS server. If the file is missing, QEMU will generate a set of 4993 DH parameters at startup. This is a computationally expensive 4994 operation that consumes random pool entropy, so it is 4995 recommended that a persistent set of parameters be generated 4996 upfront and saved. 4997 4998 For x509 certificate credentials the directory will contain 4999 further files providing the x509 certificates. The certificates 5000 must be stored in PEM format, in filenames ca-cert.pem, 5001 ca-crl.pem (optional), server-cert.pem (only servers), 5002 server-key.pem (only servers), client-cert.pem (only clients), 5003 and client-key.pem (only clients). 5004 5005 For the server-key.pem and client-key.pem files which contain 5006 sensitive private keys, it is possible to use an encrypted 5007 version by providing the passwordid parameter. This provides the 5008 ID of a previously created ``secret`` object containing the 5009 password for decryption. 5010 5011 The priority parameter allows to override the global default 5012 priority used by gnutls. This can be useful if the system 5013 administrator needs to use a weaker set of crypto priorities for 5014 QEMU without potentially forcing the weakness onto all 5015 applications. Or conversely if one wants wants a stronger 5016 default for QEMU than for all other applications, they can do 5017 this through this parameter. Its format is a gnutls priority 5018 string as described at 5019 https://gnutls.org/manual/html_node/Priority-Strings.html. 5020 5021 ``-object tls-cipher-suites,id=id,priority=priority`` 5022 Creates a TLS cipher suites object, which can be used to control 5023 the TLS cipher/protocol algorithms that applications are permitted 5024 to use. 5025 5026 The ``id`` parameter is a unique ID which frontends will use to 5027 access the ordered list of permitted TLS cipher suites from the 5028 host. 5029 5030 The ``priority`` parameter allows to override the global default 5031 priority used by gnutls. This can be useful if the system 5032 administrator needs to use a weaker set of crypto priorities for 5033 QEMU without potentially forcing the weakness onto all 5034 applications. Or conversely if one wants wants a stronger 5035 default for QEMU than for all other applications, they can do 5036 this through this parameter. Its format is a gnutls priority 5037 string as described at 5038 https://gnutls.org/manual/html_node/Priority-Strings.html. 5039 5040 An example of use of this object is to control UEFI HTTPS Boot. 5041 The tls-cipher-suites object exposes the ordered list of permitted 5042 TLS cipher suites from the host side to the guest firmware, via 5043 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5044 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5045 guest-side TLS. 5046 5047 In the following example, the priority at which the host-side policy 5048 is retrieved is given by the ``priority`` property. 5049 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5050 refer to /etc/crypto-policies/back-ends/gnutls.config. 5051 5052 .. parsed-literal:: 5053 5054 # |qemu_system| \\ 5055 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5056 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5057 5058 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5059 Interval t can't be 0, this filter batches the packet delivery: 5060 all packets arriving in a given interval on netdev netdevid are 5061 delayed until the end of the interval. Interval is in 5062 microseconds. ``status`` is optional that indicate whether the 5063 netfilter is on (enabled) or off (disabled), the default status 5064 for netfilter will be 'on'. 5065 5066 queue all\|rx\|tx is an option that can be applied to any 5067 netfilter. 5068 5069 ``all``: the filter is attached both to the receive and the 5070 transmit queue of the netdev (default). 5071 5072 ``rx``: the filter is attached to the receive queue of the 5073 netdev, where it will receive packets sent to the netdev. 5074 5075 ``tx``: the filter is attached to the transmit queue of the 5076 netdev, where it will receive packets sent by the netdev. 5077 5078 position head\|tail\|id=<id> is an option to specify where the 5079 filter should be inserted in the filter list. It can be applied 5080 to any netfilter. 5081 5082 ``head``: the filter is inserted at the head of the filter list, 5083 before any existing filters. 5084 5085 ``tail``: the filter is inserted at the tail of the filter list, 5086 behind any existing filters (default). 5087 5088 ``id=<id>``: the filter is inserted before or behind the filter 5089 specified by <id>, see the insert option below. 5090 5091 insert behind\|before is an option to specify where to insert 5092 the new filter relative to the one specified with 5093 position=id=<id>. It can be applied to any netfilter. 5094 5095 ``before``: insert before the specified filter. 5096 5097 ``behind``: insert behind the specified filter (default). 5098 5099 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5100 filter-mirror on netdev netdevid,mirror net packet to 5101 chardevchardevid, if it has the vnet\_hdr\_support flag, 5102 filter-mirror will mirror packet with vnet\_hdr\_len. 5103 5104 ``-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]`` 5105 filter-redirector on netdev netdevid,redirect filter's net 5106 packet to chardev chardevid,and redirect indev's packet to 5107 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5108 will redirect packet with vnet\_hdr\_len. Create a 5109 filter-redirector we need to differ outdev id from indev id, id 5110 can not be the same. we can just use indev or outdev, but at 5111 least one of indev or outdev need to be specified. 5112 5113 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5114 Filter-rewriter is a part of COLO project.It will rewrite tcp 5115 packet to secondary from primary to keep secondary tcp 5116 connection,and rewrite tcp packet to primary from secondary make 5117 tcp packet can be handled by client.if it has the 5118 vnet\_hdr\_support flag, we can parse packet with vnet header. 5119 5120 usage: colo secondary: -object 5121 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5122 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5123 filter-rewriter,id=rew0,netdev=hn0,queue=all 5124 5125 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5126 Dump the network traffic on netdev dev to the file specified by 5127 filename. At most len bytes (64k by default) per packet are 5128 stored. The file format is libpcap, so it can be analyzed with 5129 tools such as tcpdump or Wireshark. 5130 5131 ``-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}]`` 5132 Colo-compare gets packet from primary\_in chardevid and 5133 secondary\_in, then compare whether the payload of primary packet 5134 and secondary packet are the same. If same, it will output 5135 primary packet to out\_dev, else it will notify COLO-framework to do 5136 checkpoint and send primary packet to out\_dev. In order to 5137 improve efficiency, we need to put the task of comparison in 5138 another iothread. If it has the vnet\_hdr\_support flag, 5139 colo compare will send/recv packet with vnet\_hdr\_len. 5140 The compare\_timeout=@var{ms} determines the maximum time of the 5141 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5142 is to set the period of scanning expired primary node network packets. 5143 The max\_queue\_size=@var{size} is to set the max compare queue 5144 size depend on user environment. 5145 If user want to use Xen COLO, need to add the notify\_dev to 5146 notify Xen colo-frame to do checkpoint. 5147 5148 COLO-compare must be used with the help of filter-mirror, 5149 filter-redirector and filter-rewriter. 5150 5151 :: 5152 5153 KVM COLO 5154 5155 primary: 5156 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5157 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5158 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5159 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5160 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5161 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5162 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5163 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5164 -object iothread,id=iothread1 5165 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5166 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5167 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5168 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5169 5170 secondary: 5171 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5172 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5173 -chardev socket,id=red0,host=3.3.3.3,port=9003 5174 -chardev socket,id=red1,host=3.3.3.3,port=9004 5175 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5176 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5177 5178 5179 Xen COLO 5180 5181 primary: 5182 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5183 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5184 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5185 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5186 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5187 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5188 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5189 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5190 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5191 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5192 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5193 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5194 -object iothread,id=iothread1 5195 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5196 5197 secondary: 5198 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5199 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5200 -chardev socket,id=red0,host=3.3.3.3,port=9003 5201 -chardev socket,id=red1,host=3.3.3.3,port=9004 5202 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5203 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5204 5205 If you want to know the detail of above command line, you can 5206 read the colo-compare git log. 5207 5208 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5209 Creates a cryptodev backend which executes crypto opreation from 5210 the QEMU cipher APIS. The id parameter is a unique ID that will 5211 be used to reference this cryptodev backend from the 5212 ``virtio-crypto`` device. The queues parameter is optional, 5213 which specify the queue number of cryptodev backend, the default 5214 of queues is 1. 5215 5216 .. parsed-literal:: 5217 5218 # |qemu_system| \\ 5219 [...] \\ 5220 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5221 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5222 [...] 5223 5224 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5225 Creates a vhost-user cryptodev backend, backed by a chardev 5226 chardevid. The id parameter is a unique ID that will be used to 5227 reference this cryptodev backend from the ``virtio-crypto`` 5228 device. The chardev should be a unix domain socket backed one. 5229 The vhost-user uses a specifically defined protocol to pass 5230 vhost ioctl replacement messages to an application on the other 5231 end of the socket. The queues parameter is optional, which 5232 specify the queue number of cryptodev backend for multiqueue 5233 vhost-user, the default of queues is 1. 5234 5235 .. parsed-literal:: 5236 5237 # |qemu_system| \\ 5238 [...] \\ 5239 -chardev socket,id=chardev0,path=/path/to/socket \\ 5240 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5241 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5242 [...] 5243 5244 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5245 \ 5246 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5247 Defines a secret to store a password, encryption key, or some 5248 other sensitive data. The sensitive data can either be passed 5249 directly via the data parameter, or indirectly via the file 5250 parameter. Using the data parameter is insecure unless the 5251 sensitive data is encrypted. 5252 5253 The sensitive data can be provided in raw format (the default), 5254 or base64. When encoded as JSON, the raw format only supports 5255 valid UTF-8 characters, so base64 is recommended for sending 5256 binary data. QEMU will convert from which ever format is 5257 provided to the format it needs internally. eg, an RBD password 5258 can be provided in raw format, even though it will be base64 5259 encoded when passed onto the RBD sever. 5260 5261 For added protection, it is possible to encrypt the data 5262 associated with a secret using the AES-256-CBC cipher. Use of 5263 encryption is indicated by providing the keyid and iv 5264 parameters. The keyid parameter provides the ID of a previously 5265 defined secret that contains the AES-256 decryption key. This 5266 key should be 32-bytes long and be base64 encoded. The iv 5267 parameter provides the random initialization vector used for 5268 encryption of this particular secret and should be a base64 5269 encrypted string of the 16-byte IV. 5270 5271 The simplest (insecure) usage is to provide the secret inline 5272 5273 .. parsed-literal:: 5274 5275 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5276 5277 The simplest secure usage is to provide the secret via a file 5278 5279 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5280 secret,id=sec0,file=mypasswd.txt,format=raw 5281 5282 For greater security, AES-256-CBC should be used. To illustrate 5283 usage, consider the openssl command line tool which can encrypt 5284 the data. Note that when encrypting, the plaintext must be 5285 padded to the cipher block size (32 bytes) using the standard 5286 PKCS#5/6 compatible padding algorithm. 5287 5288 First a master key needs to be created in base64 encoding: 5289 5290 :: 5291 5292 # openssl rand -base64 32 > key.b64 5293 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5294 5295 Each secret to be encrypted needs to have a random 5296 initialization vector generated. These do not need to be kept 5297 secret 5298 5299 :: 5300 5301 # openssl rand -base64 16 > iv.b64 5302 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5303 5304 The secret to be defined can now be encrypted, in this case 5305 we're telling openssl to base64 encode the result, but it could 5306 be left as raw bytes if desired. 5307 5308 :: 5309 5310 # SECRET=$(printf "letmein" | 5311 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5312 5313 When launching QEMU, create a master secret pointing to 5314 ``key.b64`` and specify that to be used to decrypt the user 5315 password. Pass the contents of ``iv.b64`` to the second secret 5316 5317 .. parsed-literal:: 5318 5319 # |qemu_system| \\ 5320 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5321 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5322 data=$SECRET,iv=$(<iv.b64) 5323 5324 ``-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]`` 5325 Create a Secure Encrypted Virtualization (SEV) guest object, 5326 which can be used to provide the guest memory encryption support 5327 on AMD processors. 5328 5329 When memory encryption is enabled, one of the physical address 5330 bit (aka the C-bit) is utilized to mark if a memory page is 5331 protected. The ``cbitpos`` is used to provide the C-bit 5332 position. The C-bit position is Host family dependent hence user 5333 must provide this value. On EPYC, the value should be 47. 5334 5335 When memory encryption is enabled, we loose certain bits in 5336 physical address space. The ``reduced-phys-bits`` is used to 5337 provide the number of bits we loose in physical address space. 5338 Similar to C-bit, the value is Host family dependent. On EPYC, 5339 the value should be 5. 5340 5341 The ``sev-device`` provides the device file to use for 5342 communicating with the SEV firmware running inside AMD Secure 5343 Processor. The default device is '/dev/sev'. If hardware 5344 supports memory encryption then /dev/sev devices are created by 5345 CCP driver. 5346 5347 The ``policy`` provides the guest policy to be enforced by the 5348 SEV firmware and restrict what configuration and operational 5349 commands can be performed on this guest by the hypervisor. The 5350 policy should be provided by the guest owner and is bound to the 5351 guest and cannot be changed throughout the lifetime of the 5352 guest. The default is 0. 5353 5354 If guest ``policy`` allows sharing the key with another SEV 5355 guest then ``handle`` can be use to provide handle of the guest 5356 from which to share the key. 5357 5358 The ``dh-cert-file`` and ``session-file`` provides the guest 5359 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5360 and session parameters are used for establishing a cryptographic 5361 session with the guest owner to negotiate keys used for 5362 attestation. The file must be encoded in base64. 5363 5364 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5365 cmdline to a designated guest firmware page for measured Linux 5366 boot with -kernel. The default is off. (Since 6.2) 5367 5368 e.g to launch a SEV guest 5369 5370 .. parsed-literal:: 5371 5372 # |qemu_system_x86| \\ 5373 ...... \\ 5374 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5375 -machine ...,memory-encryption=sev0 \\ 5376 ..... 5377 5378 ``-object authz-simple,id=id,identity=string`` 5379 Create an authorization object that will control access to 5380 network services. 5381 5382 The ``identity`` parameter is identifies the user and its format 5383 depends on the network service that authorization object is 5384 associated with. For authorizing based on TLS x509 certificates, 5385 the identity must be the x509 distinguished name. Note that care 5386 must be taken to escape any commas in the distinguished name. 5387 5388 An example authorization object to validate a x509 distinguished 5389 name would look like: 5390 5391 .. parsed-literal:: 5392 5393 # |qemu_system| \\ 5394 ... \\ 5395 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5396 ... 5397 5398 Note the use of quotes due to the x509 distinguished name 5399 containing whitespace, and escaping of ','. 5400 5401 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5402 Create an authorization object that will control access to 5403 network services. 5404 5405 The ``filename`` parameter is the fully qualified path to a file 5406 containing the access control list rules in JSON format. 5407 5408 An example set of rules that match against SASL usernames might 5409 look like: 5410 5411 :: 5412 5413 { 5414 "rules": [ 5415 { "match": "fred", "policy": "allow", "format": "exact" }, 5416 { "match": "bob", "policy": "allow", "format": "exact" }, 5417 { "match": "danb", "policy": "deny", "format": "glob" }, 5418 { "match": "dan*", "policy": "allow", "format": "exact" }, 5419 ], 5420 "policy": "deny" 5421 } 5422 5423 When checking access the object will iterate over all the rules 5424 and the first rule to match will have its ``policy`` value 5425 returned as the result. If no rules match, then the default 5426 ``policy`` value is returned. 5427 5428 The rules can either be an exact string match, or they can use 5429 the simple UNIX glob pattern matching to allow wildcards to be 5430 used. 5431 5432 If ``refresh`` is set to true the file will be monitored and 5433 automatically reloaded whenever its content changes. 5434 5435 As with the ``authz-simple`` object, the format of the identity 5436 strings being matched depends on the network service, but is 5437 usually a TLS x509 distinguished name, or a SASL username. 5438 5439 An example authorization object to validate a SASL username 5440 would look like: 5441 5442 .. parsed-literal:: 5443 5444 # |qemu_system| \\ 5445 ... \\ 5446 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5447 ... 5448 5449 ``-object authz-pam,id=id,service=string`` 5450 Create an authorization object that will control access to 5451 network services. 5452 5453 The ``service`` parameter provides the name of a PAM service to 5454 use for authorization. It requires that a file 5455 ``/etc/pam.d/service`` exist to provide the configuration for 5456 the ``account`` subsystem. 5457 5458 An example authorization object to validate a TLS x509 5459 distinguished name would look like: 5460 5461 .. parsed-literal:: 5462 5463 # |qemu_system| \\ 5464 ... \\ 5465 -object authz-pam,id=auth0,service=qemu-vnc \\ 5466 ... 5467 5468 There would then be a corresponding config file for PAM at 5469 ``/etc/pam.d/qemu-vnc`` that contains: 5470 5471 :: 5472 5473 account requisite pam_listfile.so item=user sense=allow \ 5474 file=/etc/qemu/vnc.allow 5475 5476 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5477 of x509 distingished names that are permitted access 5478 5479 :: 5480 5481 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5482 5483 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5484 Creates a dedicated event loop thread that devices can be 5485 assigned to. This is known as an IOThread. By default device 5486 emulation happens in vCPU threads or the main event loop thread. 5487 This can become a scalability bottleneck. IOThreads allow device 5488 emulation and I/O to run on other host CPUs. 5489 5490 The ``id`` parameter is a unique ID that will be used to 5491 reference this IOThread from ``-device ...,iothread=id``. 5492 Multiple devices can be assigned to an IOThread. Note that not 5493 all devices support an ``iothread`` parameter. 5494 5495 The ``query-iothreads`` QMP command lists IOThreads and reports 5496 their thread IDs so that the user can configure host CPU 5497 pinning/affinity. 5498 5499 IOThreads use an adaptive polling algorithm to reduce event loop 5500 latency. Instead of entering a blocking system call to monitor 5501 file descriptors and then pay the cost of being woken up when an 5502 event occurs, the polling algorithm spins waiting for events for 5503 a short time. The algorithm's default parameters are suitable 5504 for many cases but can be adjusted based on knowledge of the 5505 workload and/or host device latency. 5506 5507 The ``poll-max-ns`` parameter is the maximum number of 5508 nanoseconds to busy wait for events. Polling can be disabled by 5509 setting this value to 0. 5510 5511 The ``poll-grow`` parameter is the multiplier used to increase 5512 the polling time when the algorithm detects it is missing events 5513 due to not polling long enough. 5514 5515 The ``poll-shrink`` parameter is the divisor used to decrease 5516 the polling time when the algorithm detects it is spending too 5517 long polling without encountering events. 5518 5519 The ``aio-max-batch`` parameter is the maximum number of requests 5520 in a batch for the AIO engine, 0 means that the engine will use 5521 its default. 5522 5523 The IOThread parameters can be modified at run-time using the 5524 ``qom-set`` command (where ``iothread1`` is the IOThread's 5525 ``id``): 5526 5527 :: 5528 5529 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5530ERST 5531 5532 5533HXCOMM This is the last statement. Insert new options before this line! 5534 5535#undef DEF 5536#undef DEFHEADING 5537#undef ARCHHEADING 5538
