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