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 346ERST 347 348DEF("numa", HAS_ARG, QEMU_OPTION_numa, 349 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 350 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 351 "-numa dist,src=source,dst=destination,val=distance\n" 352 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 353 "-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" 354 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 355 QEMU_ARCH_ALL) 356SRST 357``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 358 \ 359``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 360 \ 361``-numa dist,src=source,dst=destination,val=distance`` 362 \ 363``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 364 \ 365``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 366 \ 367``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 368 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 369 distance from a source node to a destination node. Set the ACPI 370 Heterogeneous Memory Attributes for the given nodes. 371 372 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 373 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 374 contiguous range of CPU indexes (or a single VCPU if lastcpu is 375 omitted). A non-contiguous set of VCPUs can be represented by 376 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 377 omitted on all nodes, VCPUs are automatically split between them. 378 379 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 380 NUMA node: 381 382 :: 383 384 -numa node,cpus=0-2,cpus=5 385 386 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 387 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 388 assign CPU objects to a node using topology layout properties of 389 CPU. The set of properties is machine specific, and depends on used 390 machine type/'\ ``smp``\ ' options. It could be queried with 391 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 392 property specifies node to which CPU object will be assigned, it's 393 required for node to be declared with '\ ``node``\ ' option before 394 it's used with '\ ``cpu``\ ' option. 395 396 For example: 397 398 :: 399 400 -M pc \ 401 -smp 1,sockets=2,maxcpus=2 \ 402 -numa node,nodeid=0 -numa node,nodeid=1 \ 403 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 404 405 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 406 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 407 a given memory backend device to a node. If '\ ``mem``\ ' and 408 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 409 410 411 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 412 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 413 use it. 414 415 '\ ``initiator``\ ' is an additional option that points to an 416 initiator NUMA node that has best performance (the lowest latency or 417 largest bandwidth) to this NUMA node. Note that this option can be 418 set only when the machine property 'hmat' is set to 'on'. 419 420 Following example creates a machine with 2 NUMA nodes, node 0 has 421 CPU. node 1 has only memory, and its initiator is node 0. Note that 422 because node 0 has CPU, by default the initiator of node 0 is itself 423 and must be itself. 424 425 :: 426 427 -machine hmat=on \ 428 -m 2G,slots=2,maxmem=4G \ 429 -object memory-backend-ram,size=1G,id=m0 \ 430 -object memory-backend-ram,size=1G,id=m1 \ 431 -numa node,nodeid=0,memdev=m0 \ 432 -numa node,nodeid=1,memdev=m1,initiator=0 \ 433 -smp 2,sockets=2,maxcpus=2 \ 434 -numa cpu,node-id=0,socket-id=0 \ 435 -numa cpu,node-id=0,socket-id=1 436 437 source and destination are NUMA node IDs. distance is the NUMA 438 distance from source to destination. The distance from a node to 439 itself is always 10. If any pair of nodes is given a distance, then 440 all pairs must be given distances. Although, when distances are only 441 given in one direction for each pair of nodes, then the distances in 442 the opposite directions are assumed to be the same. If, however, an 443 asymmetrical pair of distances is given for even one node pair, then 444 all node pairs must be provided distance values for both directions, 445 even when they are symmetrical. When a node is unreachable from 446 another node, set the pair's distance to 255. 447 448 Note that the -``numa`` option doesn't allocate any of the specified 449 resources, it just assigns existing resources to NUMA nodes. This 450 means that one still has to use the ``-m``, ``-smp`` options to 451 allocate RAM and VCPUs respectively. 452 453 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 454 Information between initiator and target NUMA nodes in ACPI 455 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 456 create memory requests, usually it has one or more processors. 457 Target NUMA node contains addressable memory. 458 459 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 460 the memory hierarchy of the target NUMA node: if hierarchy is 461 'memory', the structure represents the memory performance; if 462 hierarchy is 'first-level\|second-level\|third-level', this 463 structure represents aggregated performance of memory side caches 464 for each domain. type of 'data-type' is type of data represented by 465 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 466 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 467 the target memory; if 'hierarchy' is 468 'first-level\|second-level\|third-level', 'data-type' is 469 'access\|read\|write' hit latency or 'access\|read\|write' hit 470 bandwidth of the target memory side cache. 471 472 lat is latency value in nanoseconds. bw is bandwidth value, the 473 possible value and units are NUM[M\|G\|T], mean that the bandwidth 474 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 475 used suffix). Note that if latency or bandwidth value is 0, means 476 the corresponding latency or bandwidth information is not provided. 477 478 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 479 belongs. size is the size of memory side cache in bytes. level is 480 the cache level described in this structure, note that the cache 481 level 0 should not be used with '\ ``hmat-cache``\ ' option. 482 associativity is the cache associativity, the possible value is 483 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 484 is the write policy. line is the cache Line size in bytes. 485 486 For example, the following options describe 2 NUMA nodes. Node 0 has 487 2 cpus and a ram, node 1 has only a ram. The processors in node 0 488 access memory in node 0 with access-latency 5 nanoseconds, 489 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 490 memory in NUMA node 1 with access-latency 10 nanoseconds, 491 access-bandwidth is 100 MB/s. And for memory side cache information, 492 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 493 policy is write-back, the cache Line size is 8 bytes: 494 495 :: 496 497 -machine hmat=on \ 498 -m 2G \ 499 -object memory-backend-ram,size=1G,id=m0 \ 500 -object memory-backend-ram,size=1G,id=m1 \ 501 -smp 2,sockets=2,maxcpus=2 \ 502 -numa node,nodeid=0,memdev=m0 \ 503 -numa node,nodeid=1,memdev=m1,initiator=0 \ 504 -numa cpu,node-id=0,socket-id=0 \ 505 -numa cpu,node-id=0,socket-id=1 \ 506 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 507 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 508 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 509 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 510 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 511 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 512ERST 513 514DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 515 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 516 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 517SRST 518``-add-fd fd=fd,set=set[,opaque=opaque]`` 519 Add a file descriptor to an fd set. Valid options are: 520 521 ``fd=fd`` 522 This option defines the file descriptor of which a duplicate is 523 added to fd set. The file descriptor cannot be stdin, stdout, or 524 stderr. 525 526 ``set=set`` 527 This option defines the ID of the fd set to add the file 528 descriptor to. 529 530 ``opaque=opaque`` 531 This option defines a free-form string that can be used to 532 describe fd. 533 534 You can open an image using pre-opened file descriptors from an fd 535 set: 536 537 .. parsed-literal:: 538 539 |qemu_system| \\ 540 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 541 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 542 -drive file=/dev/fdset/2,index=0,media=disk 543ERST 544 545DEF("set", HAS_ARG, QEMU_OPTION_set, 546 "-set group.id.arg=value\n" 547 " set <arg> parameter for item <id> of type <group>\n" 548 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 549SRST 550``-set group.id.arg=value`` 551 Set parameter arg for item id of type group 552ERST 553 554DEF("global", HAS_ARG, QEMU_OPTION_global, 555 "-global driver.property=value\n" 556 "-global driver=driver,property=property,value=value\n" 557 " set a global default for a driver property\n", 558 QEMU_ARCH_ALL) 559SRST 560``-global driver.prop=value`` 561 \ 562``-global driver=driver,property=property,value=value`` 563 Set default value of driver's property prop to value, e.g.: 564 565 .. parsed-literal:: 566 567 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 568 569 In particular, you can use this to set driver properties for devices 570 which are created automatically by the machine model. To create a 571 device which is not created automatically and set properties on it, 572 use -``device``. 573 574 -global driver.prop=value is shorthand for -global 575 driver=driver,property=prop,value=value. The longhand syntax works 576 even when driver contains a dot. 577ERST 578 579DEF("boot", HAS_ARG, QEMU_OPTION_boot, 580 "-boot [order=drives][,once=drives][,menu=on|off]\n" 581 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 582 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 583 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 584 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 585 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 586 QEMU_ARCH_ALL) 587SRST 588``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 589 Specify boot order drives as a string of drive letters. Valid drive 590 letters depend on the target architecture. The x86 PC uses: a, b 591 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 592 (Etherboot from network adapter 1-4), hard disk boot is the default. 593 To apply a particular boot order only on the first startup, specify 594 it via ``once``. Note that the ``order`` or ``once`` parameter 595 should not be used together with the ``bootindex`` property of 596 devices, since the firmware implementations normally do not support 597 both at the same time. 598 599 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 600 as firmware/BIOS supports them. The default is non-interactive boot. 601 602 A splash picture could be passed to bios, enabling user to show it 603 as logo, when option splash=sp\_name is given and menu=on, If 604 firmware/BIOS supports them. Currently Seabios for X86 system 605 support it. limitation: The splash file could be a jpeg file or a 606 BMP file in 24 BPP format(true color). The resolution should be 607 supported by the SVGA mode, so the recommended is 320x240, 640x480, 608 800x640. 609 610 A timeout could be passed to bios, guest will pause for rb\_timeout 611 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 612 not reboot, qemu passes '-1' to bios by default. Currently Seabios 613 for X86 system support it. 614 615 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 616 it. This only effects when boot priority is changed by bootindex 617 options. The default is non-strict boot. 618 619 .. parsed-literal:: 620 621 # try to boot from network first, then from hard disk 622 |qemu_system_x86| -boot order=nc 623 # boot from CD-ROM first, switch back to default order after reboot 624 |qemu_system_x86| -boot once=d 625 # boot with a splash picture for 5 seconds. 626 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 627 628 Note: The legacy format '-boot drives' is still supported but its 629 use is discouraged as it may be removed from future versions. 630ERST 631 632DEF("m", HAS_ARG, QEMU_OPTION_m, 633 "-m [size=]megs[,slots=n,maxmem=size]\n" 634 " configure guest RAM\n" 635 " size: initial amount of guest memory\n" 636 " slots: number of hotplug slots (default: none)\n" 637 " maxmem: maximum amount of guest memory (default: none)\n" 638 "NOTE: Some architectures might enforce a specific granularity\n", 639 QEMU_ARCH_ALL) 640SRST 641``-m [size=]megs[,slots=n,maxmem=size]`` 642 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 643 Optionally, a suffix of "M" or "G" can be used to signify a value in 644 megabytes or gigabytes respectively. Optional pair slots, maxmem 645 could be used to set amount of hotpluggable memory slots and maximum 646 amount of memory. Note that maxmem must be aligned to the page size. 647 648 For example, the following command-line sets the guest startup RAM 649 size to 1GB, creates 3 slots to hotplug additional memory and sets 650 the maximum memory the guest can reach to 4GB: 651 652 .. parsed-literal:: 653 654 |qemu_system| -m 1G,slots=3,maxmem=4G 655 656 If slots and maxmem are not specified, memory hotplug won't be 657 enabled and the guest startup RAM will never increase. 658ERST 659 660DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 661 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 662SRST 663``-mem-path path`` 664 Allocate guest RAM from a temporarily created file in path. 665ERST 666 667DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 668 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 669 QEMU_ARCH_ALL) 670SRST 671``-mem-prealloc`` 672 Preallocate memory when using -mem-path. 673ERST 674 675DEF("k", HAS_ARG, QEMU_OPTION_k, 676 "-k language use keyboard layout (for example 'fr' for French)\n", 677 QEMU_ARCH_ALL) 678SRST 679``-k language`` 680 Use keyboard layout language (for example ``fr`` for French). This 681 option is only needed where it is not easy to get raw PC keycodes 682 (e.g. on Macs, with some X11 servers or with a VNC or curses 683 display). You don't normally need to use it on PC/Linux or 684 PC/Windows hosts. 685 686 The available layouts are: 687 688 :: 689 690 ar de-ch es fo fr-ca hu ja mk no pt-br sv 691 da en-gb et fr fr-ch is lt nl pl ru th 692 de en-us fi fr-be hr it lv nl-be pt sl tr 693 694 The default is ``en-us``. 695ERST 696 697 698HXCOMM Deprecated by -audiodev 699DEF("audio-help", 0, QEMU_OPTION_audio_help, 700 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 701 QEMU_ARCH_ALL) 702SRST 703``-audio-help`` 704 Will show the -audiodev equivalent of the currently specified 705 (deprecated) environment variables. 706ERST 707 708DEF("audio", HAS_ARG, QEMU_OPTION_audio, 709 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 710 " specifies the audio backend and device to use;\n" 711 " apart from 'model', options are the same as for -audiodev.\n" 712 " use '-audio model=help' to show possible devices.\n", 713 QEMU_ARCH_ALL) 714SRST 715``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 716 This option is a shortcut for configuring both the guest audio 717 hardware and the host audio backend in one go. 718 The driver option is the same as with the corresponding ``-audiodev`` option below. 719 The guest hardware model can be set with ``model=modelname``. 720 721 Use ``driver=help`` to list the available drivers, 722 and ``model=help`` to list the available device types. 723 724 The following two example do exactly the same, to show how ``-audio`` 725 can be used to shorten the command line length: 726 727 .. parsed-literal:: 728 729 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 730 |qemu_system| -audio pa,model=sb16 731ERST 732 733DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 734 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 735 " specifies the audio backend to use\n" 736 " Use ``-audiodev help`` to list the available drivers\n" 737 " id= identifier of the backend\n" 738 " timer-period= timer period in microseconds\n" 739 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 740 " in|out.fixed-settings= use fixed settings for host audio\n" 741 " in|out.frequency= frequency to use with fixed settings\n" 742 " in|out.channels= number of channels to use with fixed settings\n" 743 " in|out.format= sample format to use with fixed settings\n" 744 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 745 " in|out.voices= number of voices to use\n" 746 " in|out.buffer-length= length of buffer in microseconds\n" 747 "-audiodev none,id=id,[,prop[=value][,...]]\n" 748 " dummy driver that discards all output\n" 749#ifdef CONFIG_AUDIO_ALSA 750 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 751 " in|out.dev= name of the audio device to use\n" 752 " in|out.period-length= length of period in microseconds\n" 753 " in|out.try-poll= attempt to use poll mode\n" 754 " threshold= threshold (in microseconds) when playback starts\n" 755#endif 756#ifdef CONFIG_AUDIO_COREAUDIO 757 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 758 " in|out.buffer-count= number of buffers\n" 759#endif 760#ifdef CONFIG_AUDIO_DSOUND 761 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 762 " latency= add extra latency to playback in microseconds\n" 763#endif 764#ifdef CONFIG_AUDIO_OSS 765 "-audiodev oss,id=id[,prop[=value][,...]]\n" 766 " in|out.dev= path of the audio device to use\n" 767 " in|out.buffer-count= number of buffers\n" 768 " in|out.try-poll= attempt to use poll mode\n" 769 " try-mmap= try using memory mapped access\n" 770 " exclusive= open device in exclusive mode\n" 771 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 772#endif 773#ifdef CONFIG_AUDIO_PA 774 "-audiodev pa,id=id[,prop[=value][,...]]\n" 775 " server= PulseAudio server address\n" 776 " in|out.name= source/sink device name\n" 777 " in|out.latency= desired latency in microseconds\n" 778#endif 779#ifdef CONFIG_AUDIO_SDL 780 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 781 " in|out.buffer-count= number of buffers\n" 782#endif 783#ifdef CONFIG_AUDIO_SNDIO 784 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 785#endif 786#ifdef CONFIG_SPICE 787 "-audiodev spice,id=id[,prop[=value][,...]]\n" 788#endif 789#ifdef CONFIG_DBUS_DISPLAY 790 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 791#endif 792 "-audiodev wav,id=id[,prop[=value][,...]]\n" 793 " path= path of wav file to record\n", 794 QEMU_ARCH_ALL) 795SRST 796``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 797 Adds a new audio backend driver identified by id. There are global 798 and driver specific properties. Some values can be set differently 799 for input and output, they're marked with ``in|out.``. You can set 800 the input's property with ``in.prop`` and the output's property with 801 ``out.prop``. For example: 802 803 :: 804 805 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 806 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 807 808 NOTE: parameter validation is known to be incomplete, in many cases 809 specifying an invalid option causes QEMU to print an error message 810 and continue emulation without sound. 811 812 Valid global options are: 813 814 ``id=identifier`` 815 Identifies the audio backend. 816 817 ``timer-period=period`` 818 Sets the timer period used by the audio subsystem in 819 microseconds. Default is 10000 (10 ms). 820 821 ``in|out.mixing-engine=on|off`` 822 Use QEMU's mixing engine to mix all streams inside QEMU and 823 convert audio formats when not supported by the backend. When 824 off, fixed-settings must be off too. Note that disabling this 825 option means that the selected backend must support multiple 826 streams and the audio formats used by the virtual cards, 827 otherwise you'll get no sound. It's not recommended to disable 828 this option unless you want to use 5.1 or 7.1 audio, as mixing 829 engine only supports mono and stereo audio. Default is on. 830 831 ``in|out.fixed-settings=on|off`` 832 Use fixed settings for host audio. When off, it will change 833 based on how the guest opens the sound card. In this case you 834 must not specify frequency, channels or format. Default is on. 835 836 ``in|out.frequency=frequency`` 837 Specify the frequency to use when using fixed-settings. Default 838 is 44100Hz. 839 840 ``in|out.channels=channels`` 841 Specify the number of channels to use when using fixed-settings. 842 Default is 2 (stereo). 843 844 ``in|out.format=format`` 845 Specify the sample format to use when using fixed-settings. 846 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 847 ``u32``, ``f32``. Default is ``s16``. 848 849 ``in|out.voices=voices`` 850 Specify the number of voices to use. Default is 1. 851 852 ``in|out.buffer-length=usecs`` 853 Sets the size of the buffer in microseconds. 854 855``-audiodev none,id=id[,prop[=value][,...]]`` 856 Creates a dummy backend that discards all outputs. This backend has 857 no backend specific properties. 858 859``-audiodev alsa,id=id[,prop[=value][,...]]`` 860 Creates backend using the ALSA. This backend is only available on 861 Linux. 862 863 ALSA specific options are: 864 865 ``in|out.dev=device`` 866 Specify the ALSA device to use for input and/or output. Default 867 is ``default``. 868 869 ``in|out.period-length=usecs`` 870 Sets the period length in microseconds. 871 872 ``in|out.try-poll=on|off`` 873 Attempt to use poll mode with the device. Default is on. 874 875 ``threshold=threshold`` 876 Threshold (in microseconds) when playback starts. Default is 0. 877 878``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 879 Creates a backend using Apple's Core Audio. This backend is only 880 available on Mac OS and only supports playback. 881 882 Core Audio specific options are: 883 884 ``in|out.buffer-count=count`` 885 Sets the count of the buffers. 886 887``-audiodev dsound,id=id[,prop[=value][,...]]`` 888 Creates a backend using Microsoft's DirectSound. This backend is 889 only available on Windows and only supports playback. 890 891 DirectSound specific options are: 892 893 ``latency=usecs`` 894 Add extra usecs microseconds latency to playback. Default is 895 10000 (10 ms). 896 897``-audiodev oss,id=id[,prop[=value][,...]]`` 898 Creates a backend using OSS. This backend is available on most 899 Unix-like systems. 900 901 OSS specific options are: 902 903 ``in|out.dev=device`` 904 Specify the file name of the OSS device to use. Default is 905 ``/dev/dsp``. 906 907 ``in|out.buffer-count=count`` 908 Sets the count of the buffers. 909 910 ``in|out.try-poll=on|of`` 911 Attempt to use poll mode with the device. Default is on. 912 913 ``try-mmap=on|off`` 914 Try using memory mapped device access. Default is off. 915 916 ``exclusive=on|off`` 917 Open the device in exclusive mode (vmix won't work in this 918 case). Default is off. 919 920 ``dsp-policy=policy`` 921 Sets the timing policy (between 0 and 10, where smaller number 922 means smaller latency but higher CPU usage). Use -1 to use 923 buffer sizes specified by ``buffer`` and ``buffer-count``. This 924 option is ignored if you do not have OSS 4. Default is 5. 925 926``-audiodev pa,id=id[,prop[=value][,...]]`` 927 Creates a backend using PulseAudio. This backend is available on 928 most systems. 929 930 PulseAudio specific options are: 931 932 ``server=server`` 933 Sets the PulseAudio server to connect to. 934 935 ``in|out.name=sink`` 936 Use the specified source/sink for recording/playback. 937 938 ``in|out.latency=usecs`` 939 Desired latency in microseconds. The PulseAudio server will try 940 to honor this value but actual latencies may be lower or higher. 941 942``-audiodev sdl,id=id[,prop[=value][,...]]`` 943 Creates a backend using SDL. This backend is available on most 944 systems, but you should use your platform's native backend if 945 possible. 946 947 SDL specific options are: 948 949 ``in|out.buffer-count=count`` 950 Sets the count of the buffers. 951 952``-audiodev sndio,id=id[,prop[=value][,...]]`` 953 Creates a backend using SNDIO. This backend is available on 954 OpenBSD and most other Unix-like systems. 955 956 Sndio specific options are: 957 958 ``in|out.dev=device`` 959 Specify the sndio device to use for input and/or output. Default 960 is ``default``. 961 962 ``in|out.latency=usecs`` 963 Sets the desired period length in microseconds. 964 965``-audiodev spice,id=id[,prop[=value][,...]]`` 966 Creates a backend that sends audio through SPICE. This backend 967 requires ``-spice`` and automatically selected in that case, so 968 usually you can ignore this option. This backend has no backend 969 specific properties. 970 971``-audiodev wav,id=id[,prop[=value][,...]]`` 972 Creates a backend that writes audio to a WAV file. 973 974 Backend specific options are: 975 976 ``path=path`` 977 Write recorded audio into the specified file. Default is 978 ``qemu.wav``. 979ERST 980 981DEF("device", HAS_ARG, QEMU_OPTION_device, 982 "-device driver[,prop[=value][,...]]\n" 983 " add device (based on driver)\n" 984 " prop=value,... sets driver properties\n" 985 " use '-device help' to print all possible drivers\n" 986 " use '-device driver,help' to print all possible properties\n", 987 QEMU_ARCH_ALL) 988SRST 989``-device driver[,prop[=value][,...]]`` 990 Add device driver. prop=value sets driver properties. Valid 991 properties depend on the driver. To get help on possible drivers and 992 properties, use ``-device help`` and ``-device driver,help``. 993 994 Some drivers are: 995 996``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 997 Add an IPMI BMC. This is a simulation of a hardware management 998 interface processor that normally sits on a system. It provides a 999 watchdog and the ability to reset and power control the system. You 1000 need to connect this to an IPMI interface to make it useful 1001 1002 The IPMI slave address to use for the BMC. The default is 0x20. This 1003 address is the BMC's address on the I2C network of management 1004 controllers. If you don't know what this means, it is safe to ignore 1005 it. 1006 1007 ``id=id`` 1008 The BMC id for interfaces to use this device. 1009 1010 ``slave_addr=val`` 1011 Define slave address to use for the BMC. The default is 0x20. 1012 1013 ``sdrfile=file`` 1014 file containing raw Sensor Data Records (SDR) data. The default 1015 is none. 1016 1017 ``fruareasize=val`` 1018 size of a Field Replaceable Unit (FRU) area. The default is 1019 1024. 1020 1021 ``frudatafile=file`` 1022 file containing raw Field Replaceable Unit (FRU) inventory data. 1023 The default is none. 1024 1025 ``guid=uuid`` 1026 value for the GUID for the BMC, in standard UUID format. If this 1027 is set, get "Get GUID" command to the BMC will return it. 1028 Otherwise "Get GUID" will return an error. 1029 1030``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1031 Add a connection to an external IPMI BMC simulator. Instead of 1032 locally emulating the BMC like the above item, instead connect to an 1033 external entity that provides the IPMI services. 1034 1035 A connection is made to an external BMC simulator. If you do this, 1036 it is strongly recommended that you use the "reconnect=" chardev 1037 option to reconnect to the simulator if the connection is lost. Note 1038 that if this is not used carefully, it can be a security issue, as 1039 the interface has the ability to send resets, NMIs, and power off 1040 the VM. It's best if QEMU makes a connection to an external 1041 simulator running on a secure port on localhost, so neither the 1042 simulator nor QEMU is exposed to any outside network. 1043 1044 See the "lanserv/README.vm" file in the OpenIPMI library for more 1045 details on the external interface. 1046 1047``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1048 Add a KCS IPMI interface on the ISA bus. This also adds a 1049 corresponding ACPI and SMBIOS entries, if appropriate. 1050 1051 ``bmc=id`` 1052 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1053 above. 1054 1055 ``ioport=val`` 1056 Define the I/O address of the interface. The default is 0xca0 1057 for KCS. 1058 1059 ``irq=val`` 1060 Define the interrupt to use. The default is 5. To disable 1061 interrupts, set this to 0. 1062 1063``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1064 Like the KCS interface, but defines a BT interface. The default port 1065 is 0xe4 and the default interrupt is 5. 1066 1067``-device pci-ipmi-kcs,bmc=id`` 1068 Add a KCS IPMI interface on the PCI bus. 1069 1070 ``bmc=id`` 1071 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1072 1073``-device pci-ipmi-bt,bmc=id`` 1074 Like the KCS interface, but defines a BT interface on the PCI bus. 1075 1076``-device intel-iommu[,option=...]`` 1077 This is only supported by ``-machine q35``, which will enable Intel VT-d 1078 emulation within the guest. It supports below options: 1079 1080 ``intremap=on|off`` (default: auto) 1081 This enables interrupt remapping feature. It's required to enable 1082 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1083 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1084 The default value is "auto", which will be decided by the mode of 1085 kernel-irqchip. 1086 1087 ``caching-mode=on|off`` (default: off) 1088 This enables caching mode for the VT-d emulated device. When 1089 caching-mode is enabled, each guest DMA buffer mapping will generate an 1090 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1091 a synchronous way. It is required for ``-device vfio-pci`` to work 1092 with the VT-d device, because host assigned devices requires to setup 1093 the DMA mapping on the host before guest DMA starts. 1094 1095 ``device-iotlb=on|off`` (default: off) 1096 This enables device-iotlb capability for the emulated VT-d device. So 1097 far virtio/vhost should be the only real user for this parameter, 1098 paired with ats=on configured for the device. 1099 1100 ``aw-bits=39|48`` (default: 39) 1101 This decides the address width of IOVA address space. The address 1102 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1103 4-level IOMMU page tables. 1104 1105 Please also refer to the wiki page for general scenarios of VT-d 1106 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1107 1108ERST 1109 1110DEF("name", HAS_ARG, QEMU_OPTION_name, 1111 "-name string1[,process=string2][,debug-threads=on|off]\n" 1112 " set the name of the guest\n" 1113 " string1 sets the window title and string2 the process name\n" 1114 " When debug-threads is enabled, individual threads are given a separate name\n" 1115 " NOTE: The thread names are for debugging and not a stable API.\n", 1116 QEMU_ARCH_ALL) 1117SRST 1118``-name name`` 1119 Sets the name of the guest. This name will be displayed in the SDL 1120 window caption. The name will also be used for the VNC server. Also 1121 optionally set the top visible process name in Linux. Naming of 1122 individual threads can also be enabled on Linux to aid debugging. 1123ERST 1124 1125DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1126 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1127 " specify machine UUID\n", QEMU_ARCH_ALL) 1128SRST 1129``-uuid uuid`` 1130 Set system UUID. 1131ERST 1132 1133DEFHEADING() 1134 1135DEFHEADING(Block device options:) 1136 1137SRST 1138The QEMU block device handling options have a long history and 1139have gone through several iterations as the feature set and complexity 1140of the block layer have grown. Many online guides to QEMU often 1141reference older and deprecated options, which can lead to confusion. 1142 1143The recommended modern way to describe disks is to use a combination of 1144``-device`` to specify the hardware device and ``-blockdev`` to 1145describe the backend. The device defines what the guest sees and the 1146backend describes how QEMU handles the data. 1147 1148ERST 1149 1150DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1151 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1152DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1153SRST 1154``-fda file`` 1155 \ 1156``-fdb file`` 1157 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1158 the System Emulation Users Guide). 1159ERST 1160 1161DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1162 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1163DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1164DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1165 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1166DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1167SRST 1168``-hda file`` 1169 \ 1170``-hdb file`` 1171 \ 1172``-hdc file`` 1173 \ 1174``-hdd file`` 1175 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1176 chapter in the System Emulation Users Guide). 1177ERST 1178 1179DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1180 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1181 QEMU_ARCH_ALL) 1182SRST 1183``-cdrom file`` 1184 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1185 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1186 as filename. 1187ERST 1188 1189DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1190 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1191 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1192 " [,read-only=on|off][,auto-read-only=on|off]\n" 1193 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1194 " [,driver specific parameters...]\n" 1195 " configure a block backend\n", QEMU_ARCH_ALL) 1196SRST 1197``-blockdev option[,option[,option[,...]]]`` 1198 Define a new block driver node. Some of the options apply to all 1199 block drivers, other options are only accepted for a specific block 1200 driver. See below for a list of generic options and options for the 1201 most common block drivers. 1202 1203 Options that expect a reference to another node (e.g. ``file``) can 1204 be given in two ways. Either you specify the node name of an already 1205 existing node (file=node-name), or you define a new node inline, 1206 adding options for the referenced node after a dot 1207 (file.filename=path,file.aio=native). 1208 1209 A block driver node created with ``-blockdev`` can be used for a 1210 guest device by specifying its node name for the ``drive`` property 1211 in a ``-device`` argument that defines a block device. 1212 1213 ``Valid options for any block driver node:`` 1214 ``driver`` 1215 Specifies the block driver to use for the given node. 1216 1217 ``node-name`` 1218 This defines the name of the block driver node by which it 1219 will be referenced later. The name must be unique, i.e. it 1220 must not match the name of a different block driver node, or 1221 (if you use ``-drive`` as well) the ID of a drive. 1222 1223 If no node name is specified, it is automatically generated. 1224 The generated node name is not intended to be predictable 1225 and changes between QEMU invocations. For the top level, an 1226 explicit node name must be specified. 1227 1228 ``read-only`` 1229 Open the node read-only. Guest write attempts will fail. 1230 1231 Note that some block drivers support only read-only access, 1232 either generally or in certain configurations. In this case, 1233 the default value ``read-only=off`` does not work and the 1234 option must be specified explicitly. 1235 1236 ``auto-read-only`` 1237 If ``auto-read-only=on`` is set, QEMU may fall back to 1238 read-only usage even when ``read-only=off`` is requested, or 1239 even switch between modes as needed, e.g. depending on 1240 whether the image file is writable or whether a writing user 1241 is attached to the node. 1242 1243 ``force-share`` 1244 Override the image locking system of QEMU by forcing the 1245 node to utilize weaker shared access for permissions where 1246 it would normally request exclusive access. When there is 1247 the potential for multiple instances to have the same file 1248 open (whether this invocation of QEMU is the first or the 1249 second instance), both instances must permit shared access 1250 for the second instance to succeed at opening the file. 1251 1252 Enabling ``force-share=on`` requires ``read-only=on``. 1253 1254 ``cache.direct`` 1255 The host page cache can be avoided with ``cache.direct=on``. 1256 This will attempt to do disk IO directly to the guest's 1257 memory. QEMU may still perform an internal copy of the data. 1258 1259 ``cache.no-flush`` 1260 In case you don't care about data integrity over host 1261 failures, you can use ``cache.no-flush=on``. This option 1262 tells QEMU that it never needs to write any data to the disk 1263 but can instead keep things in cache. If anything goes 1264 wrong, like your host losing power, the disk storage getting 1265 disconnected accidentally, etc. your image will most 1266 probably be rendered unusable. 1267 1268 ``discard=discard`` 1269 discard is one of "ignore" (or "off") or "unmap" (or "on") 1270 and controls whether ``discard`` (also known as ``trim`` or 1271 ``unmap``) requests are ignored or passed to the filesystem. 1272 Some machine types may not support discard requests. 1273 1274 ``detect-zeroes=detect-zeroes`` 1275 detect-zeroes is "off", "on" or "unmap" and enables the 1276 automatic conversion of plain zero writes by the OS to 1277 driver specific optimized zero write commands. You may even 1278 choose "unmap" if discard is set to "unmap" to allow a zero 1279 write to be converted to an ``unmap`` operation. 1280 1281 ``Driver-specific options for file`` 1282 This is the protocol-level block driver for accessing regular 1283 files. 1284 1285 ``filename`` 1286 The path to the image file in the local filesystem 1287 1288 ``aio`` 1289 Specifies the AIO backend (threads/native/io_uring, 1290 default: threads) 1291 1292 ``locking`` 1293 Specifies whether the image file is protected with Linux OFD 1294 / POSIX locks. The default is to use the Linux Open File 1295 Descriptor API if available, otherwise no lock is applied. 1296 (auto/on/off, default: auto) 1297 1298 Example: 1299 1300 :: 1301 1302 -blockdev driver=file,node-name=disk,filename=disk.img 1303 1304 ``Driver-specific options for raw`` 1305 This is the image format block driver for raw images. It is 1306 usually stacked on top of a protocol level block driver such as 1307 ``file``. 1308 1309 ``file`` 1310 Reference to or definition of the data source block driver 1311 node (e.g. a ``file`` driver node) 1312 1313 Example 1: 1314 1315 :: 1316 1317 -blockdev driver=file,node-name=disk_file,filename=disk.img 1318 -blockdev driver=raw,node-name=disk,file=disk_file 1319 1320 Example 2: 1321 1322 :: 1323 1324 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1325 1326 ``Driver-specific options for qcow2`` 1327 This is the image format block driver for qcow2 images. It is 1328 usually stacked on top of a protocol level block driver such as 1329 ``file``. 1330 1331 ``file`` 1332 Reference to or definition of the data source block driver 1333 node (e.g. a ``file`` driver node) 1334 1335 ``backing`` 1336 Reference to or definition of the backing file block device 1337 (default is taken from the image file). It is allowed to 1338 pass ``null`` here in order to disable the default backing 1339 file. 1340 1341 ``lazy-refcounts`` 1342 Whether to enable the lazy refcounts feature (on/off; 1343 default is taken from the image file) 1344 1345 ``cache-size`` 1346 The maximum total size of the L2 table and refcount block 1347 caches in bytes (default: the sum of l2-cache-size and 1348 refcount-cache-size) 1349 1350 ``l2-cache-size`` 1351 The maximum size of the L2 table cache in bytes (default: if 1352 cache-size is not specified - 32M on Linux platforms, and 8M 1353 on non-Linux platforms; otherwise, as large as possible 1354 within the cache-size, while permitting the requested or the 1355 minimal refcount cache size) 1356 1357 ``refcount-cache-size`` 1358 The maximum size of the refcount block cache in bytes 1359 (default: 4 times the cluster size; or if cache-size is 1360 specified, the part of it which is not used for the L2 1361 cache) 1362 1363 ``cache-clean-interval`` 1364 Clean unused entries in the L2 and refcount caches. The 1365 interval is in seconds. The default value is 600 on 1366 supporting platforms, and 0 on other platforms. Setting it 1367 to 0 disables this feature. 1368 1369 ``pass-discard-request`` 1370 Whether discard requests to the qcow2 device should be 1371 forwarded to the data source (on/off; default: on if 1372 discard=unmap is specified, off otherwise) 1373 1374 ``pass-discard-snapshot`` 1375 Whether discard requests for the data source should be 1376 issued when a snapshot operation (e.g. deleting a snapshot) 1377 frees clusters in the qcow2 file (on/off; default: on) 1378 1379 ``pass-discard-other`` 1380 Whether discard requests for the data source should be 1381 issued on other occasions where a cluster gets freed 1382 (on/off; default: off) 1383 1384 ``overlap-check`` 1385 Which overlap checks to perform for writes to the image 1386 (none/constant/cached/all; default: cached). For details or 1387 finer granularity control refer to the QAPI documentation of 1388 ``blockdev-add``. 1389 1390 Example 1: 1391 1392 :: 1393 1394 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1395 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1396 1397 Example 2: 1398 1399 :: 1400 1401 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1402 1403 ``Driver-specific options for other drivers`` 1404 Please refer to the QAPI documentation of the ``blockdev-add`` 1405 QMP command. 1406ERST 1407 1408DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1409 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1410 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1411 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1412 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1413 " [,aio=threads|native|io_uring]\n" 1414 " [,readonly=on|off][,copy-on-read=on|off]\n" 1415 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1416 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1417 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1418 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1419 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1420 " [[,iops_size=is]]\n" 1421 " [[,group=g]]\n" 1422 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1423SRST 1424``-drive option[,option[,option[,...]]]`` 1425 Define a new drive. This includes creating a block driver node (the 1426 backend) as well as a guest device, and is mostly a shortcut for 1427 defining the corresponding ``-blockdev`` and ``-device`` options. 1428 1429 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1430 In addition, it knows the following options: 1431 1432 ``file=file`` 1433 This option defines which disk image (see the :ref:`disk images` 1434 chapter in the System Emulation Users Guide) to use with this drive. 1435 If the filename contains comma, you must double it (for instance, 1436 "file=my,,file" to use file "my,file"). 1437 1438 Special files such as iSCSI devices can be specified using 1439 protocol specific URLs. See the section for "Device URL Syntax" 1440 for more information. 1441 1442 ``if=interface`` 1443 This option defines on which type on interface the drive is 1444 connected. Available types are: ide, scsi, sd, mtd, floppy, 1445 pflash, virtio, none. 1446 1447 ``bus=bus,unit=unit`` 1448 These options define where is connected the drive by defining 1449 the bus number and the unit id. 1450 1451 ``index=index`` 1452 This option defines where the drive is connected by using an 1453 index in the list of available connectors of a given interface 1454 type. 1455 1456 ``media=media`` 1457 This option defines the type of the media: disk or cdrom. 1458 1459 ``snapshot=snapshot`` 1460 snapshot is "on" or "off" and controls snapshot mode for the 1461 given drive (see ``-snapshot``). 1462 1463 ``cache=cache`` 1464 cache is "none", "writeback", "unsafe", "directsync" or 1465 "writethrough" and controls how the host cache is used to access 1466 block data. This is a shortcut that sets the ``cache.direct`` 1467 and ``cache.no-flush`` options (as in ``-blockdev``), and 1468 additionally ``cache.writeback``, which provides a default for 1469 the ``write-cache`` option of block guest devices (as in 1470 ``-device``). The modes correspond to the following settings: 1471 1472 ============= =============== ============ ============== 1473 \ cache.writeback cache.direct cache.no-flush 1474 ============= =============== ============ ============== 1475 writeback on off off 1476 none on on off 1477 writethrough off off off 1478 directsync off on off 1479 unsafe on off on 1480 ============= =============== ============ ============== 1481 1482 The default mode is ``cache=writeback``. 1483 1484 ``aio=aio`` 1485 aio is "threads", "native", or "io_uring" and selects between pthread 1486 based disk I/O, native Linux AIO, or Linux io_uring API. 1487 1488 ``format=format`` 1489 Specify which disk format will be used rather than detecting the 1490 format. Can be used to specify format=raw to avoid interpreting 1491 an untrusted format header. 1492 1493 ``werror=action,rerror=action`` 1494 Specify which action to take on write and read errors. Valid 1495 actions are: "ignore" (ignore the error and try to continue), 1496 "stop" (pause QEMU), "report" (report the error to the guest), 1497 "enospc" (pause QEMU only if the host disk is full; report the 1498 error to the guest otherwise). The default setting is 1499 ``werror=enospc`` and ``rerror=report``. 1500 1501 ``copy-on-read=copy-on-read`` 1502 copy-on-read is "on" or "off" and enables whether to copy read 1503 backing file sectors into the image file. 1504 1505 ``bps=b,bps_rd=r,bps_wr=w`` 1506 Specify bandwidth throttling limits in bytes per second, either 1507 for all request types or for reads or writes only. Small values 1508 can lead to timeouts or hangs inside the guest. A safe minimum 1509 for disks is 2 MB/s. 1510 1511 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1512 Specify bursts in bytes per second, either for all request types 1513 or for reads or writes only. Bursts allow the guest I/O to spike 1514 above the limit temporarily. 1515 1516 ``iops=i,iops_rd=r,iops_wr=w`` 1517 Specify request rate limits in requests per second, either for 1518 all request types or for reads or writes only. 1519 1520 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1521 Specify bursts in requests per second, either for all request 1522 types or for reads or writes only. Bursts allow the guest I/O to 1523 spike above the limit temporarily. 1524 1525 ``iops_size=is`` 1526 Let every is bytes of a request count as a new request for iops 1527 throttling purposes. Use this option to prevent guests from 1528 circumventing iops limits by sending fewer but larger requests. 1529 1530 ``group=g`` 1531 Join a throttling quota group with given name g. All drives that 1532 are members of the same group are accounted for together. Use 1533 this option to prevent guests from circumventing throttling 1534 limits by using many small disks instead of a single larger 1535 disk. 1536 1537 By default, the ``cache.writeback=on`` mode is used. It will report 1538 data writes as completed as soon as the data is present in the host 1539 page cache. This is safe as long as your guest OS makes sure to 1540 correctly flush disk caches where needed. If your guest OS does not 1541 handle volatile disk write caches correctly and your host crashes or 1542 loses power, then the guest may experience data corruption. 1543 1544 For such guests, you should consider using ``cache.writeback=off``. 1545 This means that the host page cache will be used to read and write 1546 data, but write notification will be sent to the guest only after 1547 QEMU has made sure to flush each write to the disk. Be aware that 1548 this has a major impact on performance. 1549 1550 When using the ``-snapshot`` option, unsafe caching is always used. 1551 1552 Copy-on-read avoids accessing the same backing file sectors 1553 repeatedly and is useful when the backing file is over a slow 1554 network. By default copy-on-read is off. 1555 1556 Instead of ``-cdrom`` you can use: 1557 1558 .. parsed-literal:: 1559 1560 |qemu_system| -drive file=file,index=2,media=cdrom 1561 1562 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1563 1564 .. parsed-literal:: 1565 1566 |qemu_system| -drive file=file,index=0,media=disk 1567 |qemu_system| -drive file=file,index=1,media=disk 1568 |qemu_system| -drive file=file,index=2,media=disk 1569 |qemu_system| -drive file=file,index=3,media=disk 1570 1571 You can open an image using pre-opened file descriptors from an fd 1572 set: 1573 1574 .. parsed-literal:: 1575 1576 |qemu_system| \\ 1577 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1578 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1579 -drive file=/dev/fdset/2,index=0,media=disk 1580 1581 You can connect a CDROM to the slave of ide0: 1582 1583 .. parsed-literal:: 1584 1585 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1586 1587 If you don't specify the "file=" argument, you define an empty 1588 drive: 1589 1590 .. parsed-literal:: 1591 1592 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1593 1594 Instead of ``-fda``, ``-fdb``, you can use: 1595 1596 .. parsed-literal:: 1597 1598 |qemu_system_x86| -drive file=file,index=0,if=floppy 1599 |qemu_system_x86| -drive file=file,index=1,if=floppy 1600 1601 By default, interface is "ide" and index is automatically 1602 incremented: 1603 1604 .. parsed-literal:: 1605 1606 |qemu_system_x86| -drive file=a -drive file=b" 1607 1608 is interpreted like: 1609 1610 .. parsed-literal:: 1611 1612 |qemu_system_x86| -hda a -hdb b 1613ERST 1614 1615DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1616 "-mtdblock file use 'file' as on-board Flash memory image\n", 1617 QEMU_ARCH_ALL) 1618SRST 1619``-mtdblock file`` 1620 Use file as on-board Flash memory image. 1621ERST 1622 1623DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1624 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1625SRST 1626``-sd file`` 1627 Use file as SecureDigital card image. 1628ERST 1629 1630DEF("snapshot", 0, QEMU_OPTION_snapshot, 1631 "-snapshot write to temporary files instead of disk image files\n", 1632 QEMU_ARCH_ALL) 1633SRST 1634``-snapshot`` 1635 Write to temporary files instead of disk image files. In this case, 1636 the raw disk image you use is not written back. You can however 1637 force the write back by pressing C-a s (see the :ref:`disk images` 1638 chapter in the System Emulation Users Guide). 1639ERST 1640 1641DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1642 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1643 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1644 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1645 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1646 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1647 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1648 " [[,throttling.iops-size=is]]\n" 1649 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1650 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1651 "-fsdev synth,id=id\n", 1652 QEMU_ARCH_ALL) 1653 1654SRST 1655``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1656 \ 1657``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1658 \ 1659``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1660 \ 1661``-fsdev synth,id=id[,readonly=on]`` 1662 Define a new file system device. Valid options are: 1663 1664 ``local`` 1665 Accesses to the filesystem are done by QEMU. 1666 1667 ``proxy`` 1668 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1669 1670 ``synth`` 1671 Synthetic filesystem, only used by QTests. 1672 1673 ``id=id`` 1674 Specifies identifier for this device. 1675 1676 ``path=path`` 1677 Specifies the export path for the file system device. Files 1678 under this path will be available to the 9p client on the guest. 1679 1680 ``security_model=security_model`` 1681 Specifies the security model to be used for this export path. 1682 Supported security models are "passthrough", "mapped-xattr", 1683 "mapped-file" and "none". In "passthrough" security model, files 1684 are stored using the same credentials as they are created on the 1685 guest. This requires QEMU to run as root. In "mapped-xattr" 1686 security model, some of the file attributes like uid, gid, mode 1687 bits and link target are stored as file attributes. For 1688 "mapped-file" these attributes are stored in the hidden 1689 .virtfs\_metadata directory. Directories exported by this 1690 security model cannot interact with other unix tools. "none" 1691 security model is same as passthrough except the sever won't 1692 report failures if it fails to set file attributes like 1693 ownership. Security model is mandatory only for local fsdriver. 1694 Other fsdrivers (like proxy) don't take security model as a 1695 parameter. 1696 1697 ``writeout=writeout`` 1698 This is an optional argument. The only supported value is 1699 "immediate". This means that host page cache will be used to 1700 read and write data but write notification will be sent to the 1701 guest only when the data has been reported as written by the 1702 storage subsystem. 1703 1704 ``readonly=on`` 1705 Enables exporting 9p share as a readonly mount for guests. By 1706 default read-write access is given. 1707 1708 ``socket=socket`` 1709 Enables proxy filesystem driver to use passed socket file for 1710 communicating with virtfs-proxy-helper(1). 1711 1712 ``sock_fd=sock_fd`` 1713 Enables proxy filesystem driver to use passed socket descriptor 1714 for communicating with virtfs-proxy-helper(1). Usually a helper 1715 like libvirt will create socketpair and pass one of the fds as 1716 sock\_fd. 1717 1718 ``fmode=fmode`` 1719 Specifies the default mode for newly created files on the host. 1720 Works only with security models "mapped-xattr" and 1721 "mapped-file". 1722 1723 ``dmode=dmode`` 1724 Specifies the default mode for newly created directories on the 1725 host. Works only with security models "mapped-xattr" and 1726 "mapped-file". 1727 1728 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1729 Specify bandwidth throttling limits in bytes per second, either 1730 for all request types or for reads or writes only. 1731 1732 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1733 Specify bursts in bytes per second, either for all request types 1734 or for reads or writes only. Bursts allow the guest I/O to spike 1735 above the limit temporarily. 1736 1737 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1738 Specify request rate limits in requests per second, either for 1739 all request types or for reads or writes only. 1740 1741 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1742 Specify bursts in requests per second, either for all request 1743 types or for reads or writes only. Bursts allow the guest I/O to 1744 spike above the limit temporarily. 1745 1746 ``throttling.iops-size=is`` 1747 Let every is bytes of a request count as a new request for iops 1748 throttling purposes. 1749 1750 -fsdev option is used along with -device driver "virtio-9p-...". 1751 1752``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1753 Options for virtio-9p-... driver are: 1754 1755 ``type`` 1756 Specifies the variant to be used. Supported values are "pci", 1757 "ccw" or "device", depending on the machine type. 1758 1759 ``fsdev=id`` 1760 Specifies the id value specified along with -fsdev option. 1761 1762 ``mount_tag=mount_tag`` 1763 Specifies the tag name to be used by the guest to mount this 1764 export point. 1765ERST 1766 1767DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1768 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1769 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1770 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1771 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1772 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1773 QEMU_ARCH_ALL) 1774 1775SRST 1776``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1777 \ 1778``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1779 \ 1780``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1781 \ 1782``-virtfs synth,mount_tag=mount_tag`` 1783 Define a new virtual filesystem device and expose it to the guest using 1784 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1785 directory on host is made directly accessible by guest as a pass-through 1786 file system by using the 9P network protocol for communication between 1787 host and guests, if desired even accessible, shared by several guests 1788 simultaneously. 1789 1790 Note that ``-virtfs`` is actually just a convenience shortcut for its 1791 generalized form ``-fsdev -device virtio-9p-pci``. 1792 1793 The general form of pass-through file system options are: 1794 1795 ``local`` 1796 Accesses to the filesystem are done by QEMU. 1797 1798 ``proxy`` 1799 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1800 1801 ``synth`` 1802 Synthetic filesystem, only used by QTests. 1803 1804 ``id=id`` 1805 Specifies identifier for the filesystem device 1806 1807 ``path=path`` 1808 Specifies the export path for the file system device. Files 1809 under this path will be available to the 9p client on the guest. 1810 1811 ``security_model=security_model`` 1812 Specifies the security model to be used for this export path. 1813 Supported security models are "passthrough", "mapped-xattr", 1814 "mapped-file" and "none". In "passthrough" security model, files 1815 are stored using the same credentials as they are created on the 1816 guest. This requires QEMU to run as root. In "mapped-xattr" 1817 security model, some of the file attributes like uid, gid, mode 1818 bits and link target are stored as file attributes. For 1819 "mapped-file" these attributes are stored in the hidden 1820 .virtfs\_metadata directory. Directories exported by this 1821 security model cannot interact with other unix tools. "none" 1822 security model is same as passthrough except the sever won't 1823 report failures if it fails to set file attributes like 1824 ownership. Security model is mandatory only for local fsdriver. 1825 Other fsdrivers (like proxy) don't take security model as a 1826 parameter. 1827 1828 ``writeout=writeout`` 1829 This is an optional argument. The only supported value is 1830 "immediate". This means that host page cache will be used to 1831 read and write data but write notification will be sent to the 1832 guest only when the data has been reported as written by the 1833 storage subsystem. 1834 1835 ``readonly=on`` 1836 Enables exporting 9p share as a readonly mount for guests. By 1837 default read-write access is given. 1838 1839 ``socket=socket`` 1840 Enables proxy filesystem driver to use passed socket file for 1841 communicating with virtfs-proxy-helper(1). Usually a helper like 1842 libvirt will create socketpair and pass one of the fds as 1843 sock\_fd. 1844 1845 ``sock_fd`` 1846 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1847 socket descriptor for interfacing with virtfs-proxy-helper(1). 1848 1849 ``fmode=fmode`` 1850 Specifies the default mode for newly created files on the host. 1851 Works only with security models "mapped-xattr" and 1852 "mapped-file". 1853 1854 ``dmode=dmode`` 1855 Specifies the default mode for newly created directories on the 1856 host. Works only with security models "mapped-xattr" and 1857 "mapped-file". 1858 1859 ``mount_tag=mount_tag`` 1860 Specifies the tag name to be used by the guest to mount this 1861 export point. 1862 1863 ``multidevs=multidevs`` 1864 Specifies how to deal with multiple devices being shared with a 1865 9p export. Supported behaviours are either "remap", "forbid" or 1866 "warn". The latter is the default behaviour on which virtfs 9p 1867 expects only one device to be shared with the same export, and 1868 if more than one device is shared and accessed via the same 9p 1869 export then only a warning message is logged (once) by qemu on 1870 host side. In order to avoid file ID collisions on guest you 1871 should either create a separate virtfs export for each device to 1872 be shared with guests (recommended way) or you might use "remap" 1873 instead which allows you to share multiple devices with only one 1874 export instead, which is achieved by remapping the original 1875 inode numbers from host to guest in a way that would prevent 1876 such collisions. Remapping inodes in such use cases is required 1877 because the original device IDs from host are never passed and 1878 exposed on guest. Instead all files of an export shared with 1879 virtfs always share the same device id on guest. So two files 1880 with identical inode numbers but from actually different devices 1881 on host would otherwise cause a file ID collision and hence 1882 potential misbehaviours on guest. "forbid" on the other hand 1883 assumes like "warn" that only one device is shared by the same 1884 export, however it will not only log a warning message but also 1885 deny access to additional devices on guest. Note though that 1886 "forbid" does currently not block all possible file access 1887 operations (e.g. readdir() would still return entries from other 1888 devices). 1889ERST 1890 1891DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1892 "-iscsi [user=user][,password=password]\n" 1893 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1894 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1895 " [,timeout=timeout]\n" 1896 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1897 1898SRST 1899``-iscsi`` 1900 Configure iSCSI session parameters. 1901ERST 1902 1903DEFHEADING() 1904 1905DEFHEADING(USB convenience options:) 1906 1907DEF("usb", 0, QEMU_OPTION_usb, 1908 "-usb enable on-board USB host controller (if not enabled by default)\n", 1909 QEMU_ARCH_ALL) 1910SRST 1911``-usb`` 1912 Enable USB emulation on machine types with an on-board USB host 1913 controller (if not enabled by default). Note that on-board USB host 1914 controllers may not support USB 3.0. In this case 1915 ``-device qemu-xhci`` can be used instead on machines with PCI. 1916ERST 1917 1918DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1919 "-usbdevice name add the host or guest USB device 'name'\n", 1920 QEMU_ARCH_ALL) 1921SRST 1922``-usbdevice devname`` 1923 Add the USB device devname, and enable an on-board USB controller 1924 if possible and necessary (just like it can be done via 1925 ``-machine usb=on``). Note that this option is mainly intended for 1926 the user's convenience only. More fine-grained control can be 1927 achieved by selecting a USB host controller (if necessary) and the 1928 desired USB device via the ``-device`` option instead. For example, 1929 instead of using ``-usbdevice mouse`` it is possible to use 1930 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1931 to a USB 3.0 controller instead (at least on machines that support 1932 PCI and do not have an USB controller enabled by default yet). 1933 For more details, see the chapter about 1934 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1935 Possible devices for devname are: 1936 1937 ``braille`` 1938 Braille device. This will use BrlAPI to display the braille 1939 output on a real or fake device (i.e. it also creates a 1940 corresponding ``braille`` chardev automatically beside the 1941 ``usb-braille`` USB device). 1942 1943 ``keyboard`` 1944 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1945 1946 ``mouse`` 1947 Virtual Mouse. This will override the PS/2 mouse emulation when 1948 activated. 1949 1950 ``tablet`` 1951 Pointer device that uses absolute coordinates (like a 1952 touchscreen). This means QEMU is able to report the mouse 1953 position without having to grab the mouse. Also overrides the 1954 PS/2 mouse emulation when activated. 1955 1956 ``wacom-tablet`` 1957 Wacom PenPartner USB tablet. 1958 1959 1960ERST 1961 1962DEFHEADING() 1963 1964DEFHEADING(Display options:) 1965 1966DEF("display", HAS_ARG, QEMU_OPTION_display, 1967#if defined(CONFIG_SPICE) 1968 "-display spice-app[,gl=on|off]\n" 1969#endif 1970#if defined(CONFIG_SDL) 1971 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 1972 " [,window-close=on|off]\n" 1973#endif 1974#if defined(CONFIG_GTK) 1975 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1976 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 1977 " [,show-menubar=on|off]\n" 1978#endif 1979#if defined(CONFIG_VNC) 1980 "-display vnc=<display>[,<optargs>]\n" 1981#endif 1982#if defined(CONFIG_CURSES) 1983 "-display curses[,charset=<encoding>]\n" 1984#endif 1985#if defined(CONFIG_COCOA) 1986 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 1987#endif 1988#if defined(CONFIG_OPENGL) 1989 "-display egl-headless[,rendernode=<file>]\n" 1990#endif 1991#if defined(CONFIG_DBUS_DISPLAY) 1992 "-display dbus[,addr=<dbusaddr>]\n" 1993 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1994#endif 1995#if defined(CONFIG_COCOA) 1996 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 1997#endif 1998 "-display none\n" 1999 " select display backend type\n" 2000 " The default display is equivalent to\n " 2001#if defined(CONFIG_GTK) 2002 "\"-display gtk\"\n" 2003#elif defined(CONFIG_SDL) 2004 "\"-display sdl\"\n" 2005#elif defined(CONFIG_COCOA) 2006 "\"-display cocoa\"\n" 2007#elif defined(CONFIG_VNC) 2008 "\"-vnc localhost:0,to=99,id=default\"\n" 2009#else 2010 "\"-display none\"\n" 2011#endif 2012 , QEMU_ARCH_ALL) 2013SRST 2014``-display type`` 2015 Select type of display to use. Use ``-display help`` to list the available 2016 display types. Valid values for type are 2017 2018 ``spice-app[,gl=on|off]`` 2019 Start QEMU as a Spice server and launch the default Spice client 2020 application. The Spice server will redirect the serial consoles 2021 and QEMU monitors. (Since 4.0) 2022 2023 ``dbus`` 2024 Export the display over D-Bus interfaces. (Since 7.0) 2025 2026 The connection is registered with the "org.qemu" name (and queued when 2027 already owned). 2028 2029 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2030 2031 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2032 2033 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2034 will share framebuffers with DMABUF file descriptors). 2035 2036 ``sdl`` 2037 Display video output via SDL (usually in a separate graphics 2038 window; see the SDL documentation for other possibilities). 2039 Valid parameters are: 2040 2041 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2042 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2043 either ``lshift-lctrl-lalt`` or ``rctrl``. 2044 2045 ``gl=on|off|core|es`` : Use OpenGL for displaying 2046 2047 ``show-cursor=on|off`` : Force showing the mouse cursor 2048 2049 ``window-close=on|off`` : Allow to quit qemu with window close button 2050 2051 ``gtk`` 2052 Display video output in a GTK window. This interface provides 2053 drop-down menus and other UI elements to configure and control 2054 the VM during runtime. Valid parameters are: 2055 2056 ``full-screen=on|off`` : Start in fullscreen mode 2057 2058 ``gl=on|off`` : Use OpenGL for displaying 2059 2060 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2061 2062 ``show-tabs=on|off`` : Display the tab bar for switching between the 2063 various graphical interfaces (e.g. VGA and 2064 virtual console character devices) by default. 2065 2066 ``show-cursor=on|off`` : Force showing the mouse cursor 2067 2068 ``window-close=on|off`` : Allow to quit qemu with window close button 2069 2070 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2071 2072 ``curses[,charset=<encoding>]`` 2073 Display video output via curses. For graphics device models 2074 which support a text mode, QEMU can display this output using a 2075 curses/ncurses interface. Nothing is displayed when the graphics 2076 device is in graphical mode or if the graphics device does not 2077 support a text mode. Generally only the VGA device models 2078 support text mode. The font charset used by the guest can be 2079 specified with the ``charset`` option, for example 2080 ``charset=CP850`` for IBM CP850 encoding. The default is 2081 ``CP437``. 2082 2083 ``cocoa`` 2084 Display video output in a Cocoa window. Mac only. This interface 2085 provides drop-down menus and other UI elements to configure and 2086 control the VM during runtime. Valid parameters are: 2087 2088 ``show-cursor=on|off`` : Force showing the mouse cursor 2089 2090 ``left-command-key=on|off`` : Disable forwarding left command key to host 2091 2092 ``egl-headless[,rendernode=<file>]`` 2093 Offload all OpenGL operations to a local DRI device. For any 2094 graphical display, this display needs to be paired with either 2095 VNC or SPICE displays. 2096 2097 ``vnc=<display>`` 2098 Start a VNC server on display <display> 2099 2100 ``none`` 2101 Do not display video output. The guest will still see an 2102 emulated graphics card, but its output will not be displayed to 2103 the QEMU user. This option differs from the -nographic option in 2104 that it only affects what is done with video output; -nographic 2105 also changes the destination of the serial and parallel port 2106 data. 2107ERST 2108 2109DEF("nographic", 0, QEMU_OPTION_nographic, 2110 "-nographic disable graphical output and redirect serial I/Os to console\n", 2111 QEMU_ARCH_ALL) 2112SRST 2113``-nographic`` 2114 Normally, if QEMU is compiled with graphical window support, it 2115 displays output such as guest graphics, guest console, and the QEMU 2116 monitor in a window. With this option, you can totally disable 2117 graphical output so that QEMU is a simple command line application. 2118 The emulated serial port is redirected on the console and muxed with 2119 the monitor (unless redirected elsewhere explicitly). Therefore, you 2120 can still use QEMU to debug a Linux kernel with a serial console. 2121 Use C-a h for help on switching between the console and monitor. 2122ERST 2123 2124#ifdef CONFIG_SPICE 2125DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2126 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2127 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2128 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2129 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2130 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2131 " [,tls-ciphers=<list>]\n" 2132 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2133 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2134 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2135 " [,password=<string>][,password-secret=<secret-id>]\n" 2136 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2137 " [,jpeg-wan-compression=[auto|never|always]]\n" 2138 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2139 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2140 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2141 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2142 " [,gl=[on|off]][,rendernode=<file>]\n" 2143 " enable spice\n" 2144 " at least one of {port, tls-port} is mandatory\n", 2145 QEMU_ARCH_ALL) 2146#endif 2147SRST 2148``-spice option[,option[,...]]`` 2149 Enable the spice remote desktop protocol. Valid options are 2150 2151 ``port=<nr>`` 2152 Set the TCP port spice is listening on for plaintext channels. 2153 2154 ``addr=<addr>`` 2155 Set the IP address spice is listening on. Default is any 2156 address. 2157 2158 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2159 Force using the specified IP version. 2160 2161 ``password=<string>`` 2162 Set the password you need to authenticate. 2163 2164 This option is deprecated and insecure because it leaves the 2165 password visible in the process listing. Use ``password-secret`` 2166 instead. 2167 2168 ``password-secret=<secret-id>`` 2169 Set the ID of the ``secret`` object containing the password 2170 you need to authenticate. 2171 2172 ``sasl=on|off`` 2173 Require that the client use SASL to authenticate with the spice. 2174 The exact choice of authentication method used is controlled 2175 from the system / user's SASL configuration file for the 'qemu' 2176 service. This is typically found in /etc/sasl2/qemu.conf. If 2177 running QEMU as an unprivileged user, an environment variable 2178 SASL\_CONF\_PATH can be used to make it search alternate 2179 locations for the service config. While some SASL auth methods 2180 can also provide data encryption (eg GSSAPI), it is recommended 2181 that SASL always be combined with the 'tls' and 'x509' settings 2182 to enable use of SSL and server certificates. This ensures a 2183 data encryption preventing compromise of authentication 2184 credentials. 2185 2186 ``disable-ticketing=on|off`` 2187 Allow client connects without authentication. 2188 2189 ``disable-copy-paste=on|off`` 2190 Disable copy paste between the client and the guest. 2191 2192 ``disable-agent-file-xfer=on|off`` 2193 Disable spice-vdagent based file-xfer between the client and the 2194 guest. 2195 2196 ``tls-port=<nr>`` 2197 Set the TCP port spice is listening on for encrypted channels. 2198 2199 ``x509-dir=<dir>`` 2200 Set the x509 file directory. Expects same filenames as -vnc 2201 $display,x509=$dir 2202 2203 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2204 The x509 file names can also be configured individually. 2205 2206 ``tls-ciphers=<list>`` 2207 Specify which ciphers to use. 2208 2209 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2210 Force specific channel to be used with or without TLS 2211 encryption. The options can be specified multiple times to 2212 configure multiple channels. The special name "default" can be 2213 used to set the default mode. For channels which are not 2214 explicitly forced into one mode the spice client is allowed to 2215 pick tls/plaintext as he pleases. 2216 2217 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2218 Configure image compression (lossless). Default is auto\_glz. 2219 2220 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2221 Configure wan image compression (lossy for slow links). Default 2222 is auto. 2223 2224 ``streaming-video=[off|all|filter]`` 2225 Configure video stream detection. Default is off. 2226 2227 ``agent-mouse=[on|off]`` 2228 Enable/disable passing mouse events via vdagent. Default is on. 2229 2230 ``playback-compression=[on|off]`` 2231 Enable/disable audio stream compression (using celt 0.5.1). 2232 Default is on. 2233 2234 ``seamless-migration=[on|off]`` 2235 Enable/disable spice seamless migration. Default is off. 2236 2237 ``gl=[on|off]`` 2238 Enable/disable OpenGL context. Default is off. 2239 2240 ``rendernode=<file>`` 2241 DRM render node for OpenGL rendering. If not specified, it will 2242 pick the first available. (Since 2.9) 2243ERST 2244 2245DEF("portrait", 0, QEMU_OPTION_portrait, 2246 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2247 QEMU_ARCH_ALL) 2248SRST 2249``-portrait`` 2250 Rotate graphical output 90 deg left (only PXA LCD). 2251ERST 2252 2253DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2254 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2255 QEMU_ARCH_ALL) 2256SRST 2257``-rotate deg`` 2258 Rotate graphical output some deg left (only PXA LCD). 2259ERST 2260 2261DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2262 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2263 " select video card type\n", QEMU_ARCH_ALL) 2264SRST 2265``-vga type`` 2266 Select type of VGA card to emulate. Valid values for type are 2267 2268 ``cirrus`` 2269 Cirrus Logic GD5446 Video card. All Windows versions starting 2270 from Windows 95 should recognize and use this graphic card. For 2271 optimal performances, use 16 bit color depth in the guest and 2272 the host OS. (This card was the default before QEMU 2.2) 2273 2274 ``std`` 2275 Standard VGA card with Bochs VBE extensions. If your guest OS 2276 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2277 you want to use high resolution modes (>= 1280x1024x16) then you 2278 should use this option. (This card is the default since QEMU 2279 2.2) 2280 2281 ``vmware`` 2282 VMWare SVGA-II compatible adapter. Use it if you have 2283 sufficiently recent XFree86/XOrg server or Windows guest with a 2284 driver for this card. 2285 2286 ``qxl`` 2287 QXL paravirtual graphic card. It is VGA compatible (including 2288 VESA 2.0 VBE support). Works best with qxl guest drivers 2289 installed though. Recommended choice when using the spice 2290 protocol. 2291 2292 ``tcx`` 2293 (sun4m only) Sun TCX framebuffer. This is the default 2294 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2295 colour depths at a fixed resolution of 1024x768. 2296 2297 ``cg3`` 2298 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2299 framebuffer for sun4m machines available in both 1024x768 2300 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2301 wishing to run older Solaris versions. 2302 2303 ``virtio`` 2304 Virtio VGA card. 2305 2306 ``none`` 2307 Disable VGA card. 2308ERST 2309 2310DEF("full-screen", 0, QEMU_OPTION_full_screen, 2311 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2312SRST 2313``-full-screen`` 2314 Start in full screen. 2315ERST 2316 2317DEF("g", HAS_ARG, QEMU_OPTION_g , 2318 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2319 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2320SRST 2321``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2322 Set the initial graphical resolution and depth (PPC, SPARC only). 2323 2324 For PPC the default is 800x600x32. 2325 2326 For SPARC with the TCX graphics device, the default is 1024x768x8 2327 with the option of 1024x768x24. For cgthree, the default is 2328 1024x768x8 with the option of 1152x900x8 for people who wish to use 2329 OBP. 2330ERST 2331 2332DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2333 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2334SRST 2335``-vnc display[,option[,option[,...]]]`` 2336 Normally, if QEMU is compiled with graphical window support, it 2337 displays output such as guest graphics, guest console, and the QEMU 2338 monitor in a window. With this option, you can have QEMU listen on 2339 VNC display display and redirect the VGA display over the VNC 2340 session. It is very useful to enable the usb tablet device when 2341 using this option (option ``-device usb-tablet``). When using the 2342 VNC display, you must use the ``-k`` parameter to set the keyboard 2343 layout if you are not using en-us. Valid syntax for the display is 2344 2345 ``to=L`` 2346 With this option, QEMU will try next available VNC displays, 2347 until the number L, if the origianlly defined "-vnc display" is 2348 not available, e.g. port 5900+display is already used by another 2349 application. By default, to=0. 2350 2351 ``host:d`` 2352 TCP connections will only be allowed from host on display d. By 2353 convention the TCP port is 5900+d. Optionally, host can be 2354 omitted in which case the server will accept connections from 2355 any host. 2356 2357 ``unix:path`` 2358 Connections will be allowed over UNIX domain sockets where path 2359 is the location of a unix socket to listen for connections on. 2360 2361 ``none`` 2362 VNC is initialized but not started. The monitor ``change`` 2363 command can be used to later start the VNC server. 2364 2365 Following the display value there may be one or more option flags 2366 separated by commas. Valid options are 2367 2368 ``reverse=on|off`` 2369 Connect to a listening VNC client via a "reverse" connection. 2370 The client is specified by the display. For reverse network 2371 connections (host:d,``reverse``), the d argument is a TCP port 2372 number, not a display number. 2373 2374 ``websocket=on|off`` 2375 Opens an additional TCP listening port dedicated to VNC 2376 Websocket connections. If a bare websocket option is given, the 2377 Websocket port is 5700+display. An alternative port can be 2378 specified with the syntax ``websocket``\ =port. 2379 2380 If host is specified connections will only be allowed from this 2381 host. It is possible to control the websocket listen address 2382 independently, using the syntax ``websocket``\ =host:port. 2383 2384 If no TLS credentials are provided, the websocket connection 2385 runs in unencrypted mode. If TLS credentials are provided, the 2386 websocket connection requires encrypted client connections. 2387 2388 ``password=on|off`` 2389 Require that password based authentication is used for client 2390 connections. 2391 2392 The password must be set separately using the ``set_password`` 2393 command in the :ref:`QEMU monitor`. The 2394 syntax to change your password is: 2395 ``set_password <protocol> <password>`` where <protocol> could be 2396 either "vnc" or "spice". 2397 2398 If you would like to change <protocol> password expiration, you 2399 should use ``expire_password <protocol> <expiration-time>`` 2400 where expiration time could be one of the following options: 2401 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2402 make password expire in 60 seconds, or 1335196800 to make 2403 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2404 this date and time). 2405 2406 You can also use keywords "now" or "never" for the expiration 2407 time to allow <protocol> password to expire immediately or never 2408 expire. 2409 2410 ``password-secret=<secret-id>`` 2411 Require that password based authentication is used for client 2412 connections, using the password provided by the ``secret`` 2413 object identified by ``secret-id``. 2414 2415 ``tls-creds=ID`` 2416 Provides the ID of a set of TLS credentials to use to secure the 2417 VNC server. They will apply to both the normal VNC server socket 2418 and the websocket socket (if enabled). Setting TLS credentials 2419 will cause the VNC server socket to enable the VeNCrypt auth 2420 mechanism. The credentials should have been previously created 2421 using the ``-object tls-creds`` argument. 2422 2423 ``tls-authz=ID`` 2424 Provides the ID of the QAuthZ authorization object against which 2425 the client's x509 distinguished name will validated. This object 2426 is only resolved at time of use, so can be deleted and recreated 2427 on the fly while the VNC server is active. If missing, it will 2428 default to denying access. 2429 2430 ``sasl=on|off`` 2431 Require that the client use SASL to authenticate with the VNC 2432 server. The exact choice of authentication method used is 2433 controlled from the system / user's SASL configuration file for 2434 the 'qemu' service. This is typically found in 2435 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2436 an environment variable SASL\_CONF\_PATH can be used to make it 2437 search alternate locations for the service config. While some 2438 SASL auth methods can also provide data encryption (eg GSSAPI), 2439 it is recommended that SASL always be combined with the 'tls' 2440 and 'x509' settings to enable use of SSL and server 2441 certificates. This ensures a data encryption preventing 2442 compromise of authentication credentials. See the 2443 :ref:`VNC security` section in the System Emulation Users Guide 2444 for details on using SASL authentication. 2445 2446 ``sasl-authz=ID`` 2447 Provides the ID of the QAuthZ authorization object against which 2448 the client's SASL username will validated. This object is only 2449 resolved at time of use, so can be deleted and recreated on the 2450 fly while the VNC server is active. If missing, it will default 2451 to denying access. 2452 2453 ``acl=on|off`` 2454 Legacy method for enabling authorization of clients against the 2455 x509 distinguished name and SASL username. It results in the 2456 creation of two ``authz-list`` objects with IDs of 2457 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2458 objects must be configured with the HMP ACL commands. 2459 2460 This option is deprecated and should no longer be used. The new 2461 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2462 2463 ``lossy=on|off`` 2464 Enable lossy compression methods (gradient, JPEG, ...). If this 2465 option is set, VNC client may receive lossy framebuffer updates 2466 depending on its encoding settings. Enabling this option can 2467 save a lot of bandwidth at the expense of quality. 2468 2469 ``non-adaptive=on|off`` 2470 Disable adaptive encodings. Adaptive encodings are enabled by 2471 default. An adaptive encoding will try to detect frequently 2472 updated screen regions, and send updates in these regions using 2473 a lossy encoding (like JPEG). This can be really helpful to save 2474 bandwidth when playing videos. Disabling adaptive encodings 2475 restores the original static behavior of encodings like Tight. 2476 2477 ``share=[allow-exclusive|force-shared|ignore]`` 2478 Set display sharing policy. 'allow-exclusive' allows clients to 2479 ask for exclusive access. As suggested by the rfb spec this is 2480 implemented by dropping other connections. Connecting multiple 2481 clients in parallel requires all clients asking for a shared 2482 session (vncviewer: -shared switch). This is the default. 2483 'force-shared' disables exclusive client access. Useful for 2484 shared desktop sessions, where you don't want someone forgetting 2485 specify -shared disconnect everybody else. 'ignore' completely 2486 ignores the shared flag and allows everybody connect 2487 unconditionally. Doesn't conform to the rfb spec but is 2488 traditional QEMU behavior. 2489 2490 ``key-delay-ms`` 2491 Set keyboard delay, for key down and key up events, in 2492 milliseconds. Default is 10. Keyboards are low-bandwidth 2493 devices, so this slowdown can help the device and guest to keep 2494 up and not lose events in case events are arriving in bulk. 2495 Possible causes for the latter are flaky network connections, or 2496 scripts for automated testing. 2497 2498 ``audiodev=audiodev`` 2499 Use the specified audiodev when the VNC client requests audio 2500 transmission. When not using an -audiodev argument, this option 2501 must be omitted, otherwise is must be present and specify a 2502 valid audiodev. 2503 2504 ``power-control=on|off`` 2505 Permit the remote client to issue shutdown, reboot or reset power 2506 control requests. 2507ERST 2508 2509ARCHHEADING(, QEMU_ARCH_I386) 2510 2511ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2512 2513DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2514 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2515 QEMU_ARCH_I386) 2516SRST 2517``-win2k-hack`` 2518 Use it when installing Windows 2000 to avoid a disk full bug. After 2519 Windows 2000 is installed, you no longer need this option (this 2520 option slows down the IDE transfers). 2521ERST 2522 2523DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2524 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2525 QEMU_ARCH_I386) 2526SRST 2527``-no-fd-bootchk`` 2528 Disable boot signature checking for floppy disks in BIOS. May be 2529 needed to boot from old floppy disks. 2530ERST 2531 2532DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2533 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2534SRST 2535``-no-acpi`` 2536 Disable ACPI (Advanced Configuration and Power Interface) support. 2537 Use it if your guest OS complains about ACPI problems (PC target 2538 machine only). 2539ERST 2540 2541DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2542 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2543SRST 2544``-no-hpet`` 2545 Disable HPET support. 2546ERST 2547 2548DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2549 "-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" 2550 " ACPI table description\n", QEMU_ARCH_I386) 2551SRST 2552``-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]...]`` 2553 Add ACPI table with specified header fields and context from 2554 specified files. For file=, take whole ACPI table from the specified 2555 files, including all ACPI headers (possible overridden by other 2556 options). For data=, only data portion of the table is used, all 2557 header information is specified in the command line. If a SLIC table 2558 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2559 fields will override the same in the RSDT and the FADT (a.k.a. 2560 FACP), in order to ensure the field matches required by the 2561 Microsoft SLIC spec and the ACPI spec. 2562ERST 2563 2564DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2565 "-smbios file=binary\n" 2566 " load SMBIOS entry from binary file\n" 2567 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2568 " [,uefi=on|off]\n" 2569 " specify SMBIOS type 0 fields\n" 2570 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2571 " [,uuid=uuid][,sku=str][,family=str]\n" 2572 " specify SMBIOS type 1 fields\n" 2573 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2574 " [,asset=str][,location=str]\n" 2575 " specify SMBIOS type 2 fields\n" 2576 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2577 " [,sku=str]\n" 2578 " specify SMBIOS type 3 fields\n" 2579 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2580 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2581 " [,processor-id=%d]\n" 2582 " specify SMBIOS type 4 fields\n" 2583 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2584 " specify SMBIOS type 8 fields\n" 2585 "-smbios type=11[,value=str][,path=filename]\n" 2586 " specify SMBIOS type 11 fields\n" 2587 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2588 " [,asset=str][,part=str][,speed=%d]\n" 2589 " specify SMBIOS type 17 fields\n" 2590 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2591 " specify SMBIOS type 41 fields\n", 2592 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2593SRST 2594``-smbios file=binary`` 2595 Load SMBIOS entry from binary file. 2596 2597``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2598 Specify SMBIOS type 0 fields 2599 2600``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2601 Specify SMBIOS type 1 fields 2602 2603``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2604 Specify SMBIOS type 2 fields 2605 2606``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2607 Specify SMBIOS type 3 fields 2608 2609``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2610 Specify SMBIOS type 4 fields 2611 2612``-smbios type=11[,value=str][,path=filename]`` 2613 Specify SMBIOS type 11 fields 2614 2615 This argument can be repeated multiple times, and values are added in the order they are parsed. 2616 Applications intending to use OEM strings data are encouraged to use their application name as 2617 a prefix for the value string. This facilitates passing information for multiple applications 2618 concurrently. 2619 2620 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2621 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2622 2623 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2624 the SMBIOS table in the order in which they appear. 2625 2626 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2627 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2628 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2629 data set, for example, by specifying the serial ID of a block device. 2630 2631 An example passing three strings is 2632 2633 .. parsed-literal:: 2634 2635 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2636 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2637 path=/some/file/with/oemstringsdata.txt 2638 2639 In the guest OS this is visible with the ``dmidecode`` command 2640 2641 .. parsed-literal:: 2642 2643 $ dmidecode -t 11 2644 Handle 0x0E00, DMI type 11, 5 bytes 2645 OEM Strings 2646 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2647 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2648 String 3: myapp:some extra data 2649 2650 2651``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2652 Specify SMBIOS type 17 fields 2653 2654``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2655 Specify SMBIOS type 41 fields 2656 2657 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2658 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2659 position on the PCI bus. 2660 2661 Here is an example of use: 2662 2663 .. parsed-literal:: 2664 2665 -netdev user,id=internet \\ 2666 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2667 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2668 2669 In the guest OS, the device should then appear as ``eno1``: 2670 2671 ..parsed-literal:: 2672 2673 $ ip -brief l 2674 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2675 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2676 2677 Currently, the PCI device has to be attached to the root bus. 2678 2679ERST 2680 2681DEFHEADING() 2682 2683DEFHEADING(Network options:) 2684 2685DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2686#ifdef CONFIG_SLIRP 2687 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2688 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2689 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2690 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2691 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2692#ifndef _WIN32 2693 "[,smb=dir[,smbserver=addr]]\n" 2694#endif 2695 " configure a user mode network backend with ID 'str',\n" 2696 " its DHCP server and optional services\n" 2697#endif 2698#ifdef _WIN32 2699 "-netdev tap,id=str,ifname=name\n" 2700 " configure a host TAP network backend with ID 'str'\n" 2701#else 2702 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2703 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2704 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2705 " [,poll-us=n]\n" 2706 " configure a host TAP network backend with ID 'str'\n" 2707 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2708 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2709 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2710 " to deconfigure it\n" 2711 " use '[down]script=no' to disable script execution\n" 2712 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2713 " configure it\n" 2714 " use 'fd=h' to connect to an already opened TAP interface\n" 2715 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2716 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2717 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2718 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2719 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2720 " use vhost=on to enable experimental in kernel accelerator\n" 2721 " (only has effect for virtio guests which use MSIX)\n" 2722 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2723 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2724 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2725 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2726 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2727 " spent on busy polling for vhost net\n" 2728 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2729 " configure a host TAP network backend with ID 'str' that is\n" 2730 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2731 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2732#endif 2733#ifdef __linux__ 2734 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2735 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2736 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2737 " [,rxcookie=rxcookie][,offset=offset]\n" 2738 " configure a network backend with ID 'str' connected to\n" 2739 " an Ethernet over L2TPv3 pseudowire.\n" 2740 " Linux kernel 3.3+ as well as most routers can talk\n" 2741 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2742 " VM to a router and even VM to Host. It is a nearly-universal\n" 2743 " standard (RFC3931). Note - this implementation uses static\n" 2744 " pre-configured tunnels (same as the Linux kernel).\n" 2745 " use 'src=' to specify source address\n" 2746 " use 'dst=' to specify destination address\n" 2747 " use 'udp=on' to specify udp encapsulation\n" 2748 " use 'srcport=' to specify source udp port\n" 2749 " use 'dstport=' to specify destination udp port\n" 2750 " use 'ipv6=on' to force v6\n" 2751 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2752 " well as a weak security measure\n" 2753 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2754 " use 'txcookie=0x012345678' to specify a txcookie\n" 2755 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2756 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2757 " use 'pincounter=on' to work around broken counter handling in peer\n" 2758 " use 'offset=X' to add an extra offset between header and data\n" 2759#endif 2760 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2761 " configure a network backend to connect to another network\n" 2762 " using a socket connection\n" 2763 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2764 " configure a network backend to connect to a multicast maddr and port\n" 2765 " use 'localaddr=addr' to specify the host address to send packets from\n" 2766 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2767 " configure a network backend to connect to another network\n" 2768 " using an UDP tunnel\n" 2769 "-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]\n" 2770 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off]\n" 2771 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor\n" 2772 " configure a network backend to connect to another network\n" 2773 " using a socket connection in stream mode.\n" 2774 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2775 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2776 " configure a network backend to connect to a multicast maddr and port\n" 2777 " use ``local.host=addr`` to specify the host address to send packets from\n" 2778 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2779 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2780 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2781 " configure a network backend to connect to another network\n" 2782 " using an UDP tunnel\n" 2783#ifdef CONFIG_VDE 2784 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2785 " configure a network backend to connect to port 'n' of a vde switch\n" 2786 " running on host and listening for incoming connections on 'socketpath'.\n" 2787 " Use group 'groupname' and mode 'octalmode' to change default\n" 2788 " ownership and permissions for communication port.\n" 2789#endif 2790#ifdef CONFIG_NETMAP 2791 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2792 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2793 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2794 " netmap device, defaults to '/dev/netmap')\n" 2795#endif 2796#ifdef CONFIG_POSIX 2797 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2798 " configure a vhost-user network, backed by a chardev 'dev'\n" 2799#endif 2800#ifdef __linux__ 2801 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2802 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2803 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2804 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2805#endif 2806#ifdef CONFIG_VMNET 2807 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2808 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2809 " configure a vmnet network backend in host mode with ID 'str',\n" 2810 " isolate this interface from others with 'isolated',\n" 2811 " configure the address range and choose a subnet mask,\n" 2812 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2813 " vmnet-host interfaces within this isolated network\n" 2814 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2815 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2816 " configure a vmnet network backend in shared mode with ID 'str',\n" 2817 " configure the address range and choose a subnet mask,\n" 2818 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2819 " isolate this interface from others with 'isolated'\n" 2820 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2821 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2822 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2823 " isolate this interface from others with 'isolated'\n" 2824#endif 2825 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2826 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2827DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2828 "-nic [tap|bridge|" 2829#ifdef CONFIG_SLIRP 2830 "user|" 2831#endif 2832#ifdef __linux__ 2833 "l2tpv3|" 2834#endif 2835#ifdef CONFIG_VDE 2836 "vde|" 2837#endif 2838#ifdef CONFIG_NETMAP 2839 "netmap|" 2840#endif 2841#ifdef CONFIG_POSIX 2842 "vhost-user|" 2843#endif 2844#ifdef CONFIG_VMNET 2845 "vmnet-host|vmnet-shared|vmnet-bridged|" 2846#endif 2847 "socket][,option][,...][mac=macaddr]\n" 2848 " initialize an on-board / default host NIC (using MAC address\n" 2849 " macaddr) and connect it to the given host network backend\n" 2850 "-nic none use it alone to have zero network devices (the default is to\n" 2851 " provided a 'user' network connection)\n", 2852 QEMU_ARCH_ALL) 2853DEF("net", HAS_ARG, QEMU_OPTION_net, 2854 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2855 " configure or create an on-board (or machine default) NIC and\n" 2856 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2857 "-net [" 2858#ifdef CONFIG_SLIRP 2859 "user|" 2860#endif 2861 "tap|" 2862 "bridge|" 2863#ifdef CONFIG_VDE 2864 "vde|" 2865#endif 2866#ifdef CONFIG_NETMAP 2867 "netmap|" 2868#endif 2869#ifdef CONFIG_VMNET 2870 "vmnet-host|vmnet-shared|vmnet-bridged|" 2871#endif 2872 "socket][,option][,option][,...]\n" 2873 " old way to initialize a host network interface\n" 2874 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2875SRST 2876``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2877 This option is a shortcut for configuring both the on-board 2878 (default) guest NIC hardware and the host network backend in one go. 2879 The host backend options are the same as with the corresponding 2880 ``-netdev`` options below. The guest NIC model can be set with 2881 ``model=modelname``. Use ``model=help`` to list the available device 2882 types. The hardware MAC address can be set with ``mac=macaddr``. 2883 2884 The following two example do exactly the same, to show how ``-nic`` 2885 can be used to shorten the command line length: 2886 2887 .. parsed-literal:: 2888 2889 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2890 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2891 2892``-nic none`` 2893 Indicate that no network devices should be configured. It is used to 2894 override the default configuration (default NIC with "user" host 2895 network backend) which is activated if no other networking options 2896 are provided. 2897 2898``-netdev user,id=id[,option][,option][,...]`` 2899 Configure user mode host network backend which requires no 2900 administrator privilege to run. Valid options are: 2901 2902 ``id=id`` 2903 Assign symbolic name for use in monitor commands. 2904 2905 ``ipv4=on|off and ipv6=on|off`` 2906 Specify that either IPv4 or IPv6 must be enabled. If neither is 2907 specified both protocols are enabled. 2908 2909 ``net=addr[/mask]`` 2910 Set IP network address the guest will see. Optionally specify 2911 the netmask, either in the form a.b.c.d or as number of valid 2912 top-most bits. Default is 10.0.2.0/24. 2913 2914 ``host=addr`` 2915 Specify the guest-visible address of the host. Default is the 2916 2nd IP in the guest network, i.e. x.x.x.2. 2917 2918 ``ipv6-net=addr[/int]`` 2919 Set IPv6 network address the guest will see (default is 2920 fec0::/64). The network prefix is given in the usual hexadecimal 2921 IPv6 address notation. The prefix size is optional, and is given 2922 as the number of valid top-most bits (default is 64). 2923 2924 ``ipv6-host=addr`` 2925 Specify the guest-visible IPv6 address of the host. Default is 2926 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2927 2928 ``restrict=on|off`` 2929 If this option is enabled, the guest will be isolated, i.e. it 2930 will not be able to contact the host and no guest IP packets 2931 will be routed over the host to the outside. This option does 2932 not affect any explicitly set forwarding rules. 2933 2934 ``hostname=name`` 2935 Specifies the client hostname reported by the built-in DHCP 2936 server. 2937 2938 ``dhcpstart=addr`` 2939 Specify the first of the 16 IPs the built-in DHCP server can 2940 assign. Default is the 15th to 31st IP in the guest network, 2941 i.e. x.x.x.15 to x.x.x.31. 2942 2943 ``dns=addr`` 2944 Specify the guest-visible address of the virtual nameserver. The 2945 address must be different from the host address. Default is the 2946 3rd IP in the guest network, i.e. x.x.x.3. 2947 2948 ``ipv6-dns=addr`` 2949 Specify the guest-visible address of the IPv6 virtual 2950 nameserver. The address must be different from the host address. 2951 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2952 2953 ``dnssearch=domain`` 2954 Provides an entry for the domain-search list sent by the 2955 built-in DHCP server. More than one domain suffix can be 2956 transmitted by specifying this option multiple times. If 2957 supported, this will cause the guest to automatically try to 2958 append the given domain suffix(es) in case a domain name can not 2959 be resolved. 2960 2961 Example: 2962 2963 .. parsed-literal:: 2964 2965 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2966 2967 ``domainname=domain`` 2968 Specifies the client domain name reported by the built-in DHCP 2969 server. 2970 2971 ``tftp=dir`` 2972 When using the user mode network stack, activate a built-in TFTP 2973 server. The files in dir will be exposed as the root of a TFTP 2974 server. The TFTP client on the guest must be configured in 2975 binary mode (use the command ``bin`` of the Unix TFTP client). 2976 2977 ``tftp-server-name=name`` 2978 In BOOTP reply, broadcast name as the "TFTP server name" 2979 (RFC2132 option 66). This can be used to advise the guest to 2980 load boot files or configurations from a different server than 2981 the host address. 2982 2983 ``bootfile=file`` 2984 When using the user mode network stack, broadcast file as the 2985 BOOTP filename. In conjunction with ``tftp``, this can be used 2986 to network boot a guest from a local directory. 2987 2988 Example (using pxelinux): 2989 2990 .. parsed-literal:: 2991 2992 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2993 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2994 2995 ``smb=dir[,smbserver=addr]`` 2996 When using the user mode network stack, activate a built-in SMB 2997 server so that Windows OSes can access to the host files in 2998 ``dir`` transparently. The IP address of the SMB server can be 2999 set to addr. By default the 4th IP in the guest network is used, 3000 i.e. x.x.x.4. 3001 3002 In the guest Windows OS, the line: 3003 3004 :: 3005 3006 10.0.2.4 smbserver 3007 3008 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3009 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3010 NT/2000). 3011 3012 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3013 3014 Note that a SAMBA server must be installed on the host OS. 3015 3016 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3017 Redirect incoming TCP or UDP connections to the host port 3018 hostport to the guest IP address guestaddr on guest port 3019 guestport. If guestaddr is not specified, its value is x.x.x.15 3020 (default first address given by the built-in DHCP server). By 3021 specifying hostaddr, the rule can be bound to a specific host 3022 interface. If no connection type is set, TCP is used. This 3023 option can be given multiple times. 3024 3025 For example, to redirect host X11 connection from screen 1 to 3026 guest screen 0, use the following: 3027 3028 .. parsed-literal:: 3029 3030 # on the host 3031 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3032 # this host xterm should open in the guest X11 server 3033 xterm -display :1 3034 3035 To redirect telnet connections from host port 5555 to telnet 3036 port on the guest, use the following: 3037 3038 .. parsed-literal:: 3039 3040 # on the host 3041 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3042 telnet localhost 5555 3043 3044 Then when you use on the host ``telnet localhost 5555``, you 3045 connect to the guest telnet server. 3046 3047 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3048 Forward guest TCP connections to the IP address server on port 3049 port to the character device dev or to a program executed by 3050 cmd:command which gets spawned for each connection. This option 3051 can be given multiple times. 3052 3053 You can either use a chardev directly and have that one used 3054 throughout QEMU's lifetime, like in the following example: 3055 3056 .. parsed-literal:: 3057 3058 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3059 # the guest accesses it 3060 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3061 3062 Or you can execute a command on every TCP connection established 3063 by the guest, so that QEMU behaves similar to an inetd process 3064 for that virtual server: 3065 3066 .. parsed-literal:: 3067 3068 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3069 # and connect the TCP stream to its stdin/stdout 3070 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3071 3072``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3073 Configure a host TAP network backend with ID id. 3074 3075 Use the network script file to configure it and the network script 3076 dfile to deconfigure it. If name is not provided, the OS 3077 automatically provides one. The default network configure script is 3078 ``/etc/qemu-ifup`` and the default network deconfigure script is 3079 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3080 disable script execution. 3081 3082 If running QEMU as an unprivileged user, use the network helper 3083 to configure the TAP interface and attach it to the bridge. 3084 The default network helper executable is 3085 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3086 ``br0``. 3087 3088 ``fd``\ =h can be used to specify the handle of an already opened 3089 host TAP interface. 3090 3091 Examples: 3092 3093 .. parsed-literal:: 3094 3095 #launch a QEMU instance with the default network script 3096 |qemu_system| linux.img -nic tap 3097 3098 .. parsed-literal:: 3099 3100 #launch a QEMU instance with two NICs, each one connected 3101 #to a TAP device 3102 |qemu_system| linux.img \\ 3103 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3104 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3105 3106 .. parsed-literal:: 3107 3108 #launch a QEMU instance with the default network helper to 3109 #connect a TAP device to bridge br0 3110 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3111 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3112 3113``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3114 Connect a host TAP network interface to a host bridge device. 3115 3116 Use the network helper helper to configure the TAP interface and 3117 attach it to the bridge. The default network helper executable is 3118 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3119 ``br0``. 3120 3121 Examples: 3122 3123 .. parsed-literal:: 3124 3125 #launch a QEMU instance with the default network helper to 3126 #connect a TAP device to bridge br0 3127 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3128 3129 .. parsed-literal:: 3130 3131 #launch a QEMU instance with the default network helper to 3132 #connect a TAP device to bridge qemubr0 3133 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3134 3135``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3136 This host network backend can be used to connect the guest's network 3137 to another QEMU virtual machine using a TCP socket connection. If 3138 ``listen`` is specified, QEMU waits for incoming connections on port 3139 (host is optional). ``connect`` is used to connect to another QEMU 3140 instance using the ``listen`` option. ``fd``\ =h specifies an 3141 already opened TCP socket. 3142 3143 Example: 3144 3145 .. parsed-literal:: 3146 3147 # launch a first QEMU instance 3148 |qemu_system| linux.img \\ 3149 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3150 -netdev socket,id=n1,listen=:1234 3151 # connect the network of this instance to the network of the first instance 3152 |qemu_system| linux.img \\ 3153 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3154 -netdev socket,id=n2,connect=127.0.0.1:1234 3155 3156``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3157 Configure a socket host network backend to share the guest's network 3158 traffic with another QEMU virtual machines using a UDP multicast 3159 socket, effectively making a bus for every QEMU with same multicast 3160 address maddr and port. NOTES: 3161 3162 1. Several QEMU can be running on different hosts and share same bus 3163 (assuming correct multicast setup for these hosts). 3164 3165 2. mcast support is compatible with User Mode Linux (argument 3166 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3167 3168 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3169 3170 Example: 3171 3172 .. parsed-literal:: 3173 3174 # launch one QEMU instance 3175 |qemu_system| linux.img \\ 3176 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3177 -netdev socket,id=n1,mcast=230.0.0.1:1234 3178 # launch another QEMU instance on same "bus" 3179 |qemu_system| linux.img \\ 3180 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3181 -netdev socket,id=n2,mcast=230.0.0.1:1234 3182 # launch yet another QEMU instance on same "bus" 3183 |qemu_system| linux.img \\ 3184 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3185 -netdev socket,id=n3,mcast=230.0.0.1:1234 3186 3187 Example (User Mode Linux compat.): 3188 3189 .. parsed-literal:: 3190 3191 # launch QEMU instance (note mcast address selected is UML's default) 3192 |qemu_system| linux.img \\ 3193 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3194 -netdev socket,id=n1,mcast=239.192.168.1:1102 3195 # launch UML 3196 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3197 3198 Example (send packets from host's 1.2.3.4): 3199 3200 .. parsed-literal:: 3201 3202 |qemu_system| linux.img \\ 3203 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3204 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3205 3206``-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]`` 3207 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3208 is a popular protocol to transport Ethernet (and other Layer 2) data 3209 frames between two systems. It is present in routers, firewalls and 3210 the Linux kernel (from version 3.3 onwards). 3211 3212 This transport allows a VM to communicate to another VM, router or 3213 firewall directly. 3214 3215 ``src=srcaddr`` 3216 source address (mandatory) 3217 3218 ``dst=dstaddr`` 3219 destination address (mandatory) 3220 3221 ``udp`` 3222 select udp encapsulation (default is ip). 3223 3224 ``srcport=srcport`` 3225 source udp port. 3226 3227 ``dstport=dstport`` 3228 destination udp port. 3229 3230 ``ipv6`` 3231 force v6, otherwise defaults to v4. 3232 3233 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3234 Cookies are a weak form of security in the l2tpv3 specification. 3235 Their function is mostly to prevent misconfiguration. By default 3236 they are 32 bit. 3237 3238 ``cookie64`` 3239 Set cookie size to 64 bit instead of the default 32 3240 3241 ``counter=off`` 3242 Force a 'cut-down' L2TPv3 with no counter as in 3243 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3244 3245 ``pincounter=on`` 3246 Work around broken counter handling in peer. This may also help 3247 on networks which have packet reorder. 3248 3249 ``offset=offset`` 3250 Add an extra offset between header and data 3251 3252 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3253 the bridge br-lan on the remote Linux host 1.2.3.4: 3254 3255 .. parsed-literal:: 3256 3257 # Setup tunnel on linux host using raw ip as encapsulation 3258 # on 1.2.3.4 3259 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3260 encap udp udp_sport 16384 udp_dport 16384 3261 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3262 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3263 ifconfig vmtunnel0 mtu 1500 3264 ifconfig vmtunnel0 up 3265 brctl addif br-lan vmtunnel0 3266 3267 3268 # on 4.3.2.1 3269 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3270 3271 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3272 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3273 3274``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3275 Configure VDE backend to connect to PORT n of a vde switch running 3276 on host and listening for incoming connections on socketpath. Use 3277 GROUP groupname and MODE octalmode to change default ownership and 3278 permissions for communication port. This option is only available if 3279 QEMU has been compiled with vde support enabled. 3280 3281 Example: 3282 3283 .. parsed-literal:: 3284 3285 # launch vde switch 3286 vde_switch -F -sock /tmp/myswitch 3287 # launch QEMU instance 3288 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3289 3290``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3291 Establish a vhost-user netdev, backed by a chardev id. The chardev 3292 should be a unix domain socket backed one. The vhost-user uses a 3293 specifically defined protocol to pass vhost ioctl replacement 3294 messages to an application on the other end of the socket. On 3295 non-MSIX guests, the feature can be forced with vhostforce. Use 3296 'queues=n' to specify the number of queues to be created for 3297 multiqueue vhost-user. 3298 3299 Example: 3300 3301 :: 3302 3303 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3304 -numa node,memdev=mem \ 3305 -chardev socket,id=chr0,path=/path/to/socket \ 3306 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3307 -device virtio-net-pci,netdev=net0 3308 3309``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3310 Establish a vhost-vdpa netdev. 3311 3312 vDPA device is a device that uses a datapath which complies with 3313 the virtio specifications with a vendor specific control path. 3314 vDPA devices can be both physically located on the hardware or 3315 emulated by software. 3316 3317``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3318 Create a hub port on the emulated hub with ID hubid. 3319 3320 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3321 instead of a single netdev. Alternatively, you can also connect the 3322 hubport to another netdev with ID nd by using the ``netdev=nd`` 3323 option. 3324 3325``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3326 Legacy option to configure or create an on-board (or machine 3327 default) Network Interface Card(NIC) and connect it either to the 3328 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3329 If model is omitted, then the default NIC model associated with the 3330 machine type is used. Note that the default NIC model may change in 3331 future QEMU releases, so it is highly recommended to always specify 3332 a model. Optionally, the MAC address can be changed to mac, the 3333 device address set to addr (PCI cards only), and a name can be 3334 assigned for use in monitor commands. Optionally, for PCI cards, you 3335 can specify the number v of MSI-X vectors that the card should have; 3336 this option currently only affects virtio cards; set v = 0 to 3337 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3338 created. QEMU can emulate several different models of network card. 3339 Use ``-net nic,model=help`` for a list of available devices for your 3340 target. 3341 3342``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3343 Configure a host network backend (with the options corresponding to 3344 the same ``-netdev`` option) and connect it to the emulated hub 0 3345 (the default hub). Use name to specify the name of the hub port. 3346ERST 3347 3348DEFHEADING() 3349 3350DEFHEADING(Character device options:) 3351 3352DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3353 "-chardev help\n" 3354 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3355 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3356 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3357 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3358 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3359 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3360 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3361 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3362 " [,logfile=PATH][,logappend=on|off]\n" 3363 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3364 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3365 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3366 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3367 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3368 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3369#ifdef _WIN32 3370 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3371 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3372#else 3373 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3374 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3375#endif 3376#ifdef CONFIG_BRLAPI 3377 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3378#endif 3379#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3380 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3381 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3382 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3383#endif 3384#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3385 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3386 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3387#endif 3388#if defined(CONFIG_SPICE) 3389 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3390 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3391#endif 3392 , QEMU_ARCH_ALL 3393) 3394 3395SRST 3396The general form of a character device option is: 3397 3398``-chardev backend,id=id[,mux=on|off][,options]`` 3399 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3400 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3401 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3402 ``spicevmc``, ``spiceport``. The specific backend will determine the 3403 applicable options. 3404 3405 Use ``-chardev help`` to print all available chardev backend types. 3406 3407 All devices must have an id, which can be any string up to 127 3408 characters long. It is used to uniquely identify this device in 3409 other command line directives. 3410 3411 A character device may be used in multiplexing mode by multiple 3412 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3413 a "1:N" device, and here the "1" end is your specified chardev 3414 backend, and the "N" end is the various parts of QEMU that can talk 3415 to a chardev. If you create a chardev with ``id=myid`` and 3416 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3417 and you can then configure multiple front ends to use that chardev 3418 ID for their input/output. Up to four different front ends can be 3419 connected to a single multiplexed chardev. (Without multiplexing 3420 enabled, a chardev can only be used by a single front end.) For 3421 instance you could use this to allow a single stdio chardev to be 3422 used by two serial ports and the QEMU monitor: 3423 3424 :: 3425 3426 -chardev stdio,mux=on,id=char0 \ 3427 -mon chardev=char0,mode=readline \ 3428 -serial chardev:char0 \ 3429 -serial chardev:char0 3430 3431 You can have more than one multiplexer in a system configuration; 3432 for instance you could have a TCP port multiplexed between UART 0 3433 and UART 1, and stdio multiplexed between the QEMU monitor and a 3434 parallel port: 3435 3436 :: 3437 3438 -chardev stdio,mux=on,id=char0 \ 3439 -mon chardev=char0,mode=readline \ 3440 -parallel chardev:char0 \ 3441 -chardev tcp,...,mux=on,id=char1 \ 3442 -serial chardev:char1 \ 3443 -serial chardev:char1 3444 3445 When you're using a multiplexed character device, some escape 3446 sequences are interpreted in the input. See the chapter about 3447 :ref:`keys in the character backend multiplexer` in the 3448 System Emulation Users Guide for more details. 3449 3450 Note that some other command line options may implicitly create 3451 multiplexed character backends; for instance ``-serial mon:stdio`` 3452 creates a multiplexed stdio backend connected to the serial port and 3453 the QEMU monitor, and ``-nographic`` also multiplexes the console 3454 and the monitor to stdio. 3455 3456 There is currently no support for multiplexing in the other 3457 direction (where a single QEMU front end takes input and output from 3458 multiple chardevs). 3459 3460 Every backend supports the ``logfile`` option, which supplies the 3461 path to a file to record all data transmitted via the backend. The 3462 ``logappend`` option controls whether the log file will be truncated 3463 or appended to when opened. 3464 3465The available backends are: 3466 3467``-chardev null,id=id`` 3468 A void device. This device will not emit any data, and will drop any 3469 data it receives. The null backend does not take any options. 3470 3471``-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]`` 3472 Create a two-way stream socket, which can be either a TCP or a unix 3473 socket. A unix socket will be created if ``path`` is specified. 3474 Behaviour is undefined if TCP options are specified for a unix 3475 socket. 3476 3477 ``server=on|off`` specifies that the socket shall be a listening socket. 3478 3479 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3480 to connect to a listening socket. 3481 3482 ``telnet=on|off`` specifies that traffic on the socket should interpret 3483 telnet escape sequences. 3484 3485 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3486 communication. 3487 3488 ``reconnect`` sets the timeout for reconnecting on non-server 3489 sockets when the remote end goes away. qemu will delay this many 3490 seconds and then attempt to reconnect. Zero disables reconnecting, 3491 and is the default. 3492 3493 ``tls-creds`` requests enablement of the TLS protocol for 3494 encryption, and specifies the id of the TLS credentials to use for 3495 the handshake. The credentials must be previously created with the 3496 ``-object tls-creds`` argument. 3497 3498 ``tls-auth`` provides the ID of the QAuthZ authorization object 3499 against which the client's x509 distinguished name will be 3500 validated. This object is only resolved at time of use, so can be 3501 deleted and recreated on the fly while the chardev server is active. 3502 If missing, it will default to denying access. 3503 3504 TCP and unix socket options are given below: 3505 3506 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3507 ``host`` for a listening socket specifies the local address to 3508 be bound. For a connecting socket species the remote host to 3509 connect to. ``host`` is optional for listening sockets. If not 3510 specified it defaults to ``0.0.0.0``. 3511 3512 ``port`` for a listening socket specifies the local port to be 3513 bound. For a connecting socket specifies the port on the remote 3514 host to connect to. ``port`` can be given as either a port 3515 number or a service name. ``port`` is required. 3516 3517 ``to`` is only relevant to listening sockets. If it is 3518 specified, and ``port`` cannot be bound, QEMU will attempt to 3519 bind to subsequent ports up to and including ``to`` until it 3520 succeeds. ``to`` must be specified as a port number. 3521 3522 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3523 or IPv6 must be used. If neither is specified the socket may 3524 use either protocol. 3525 3526 ``nodelay=on|off`` disables the Nagle algorithm. 3527 3528 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3529 ``path`` specifies the local path of the unix socket. ``path`` 3530 is required. 3531 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3532 rather than the filesystem. Optional, defaults to false. 3533 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3534 rather than the full sun_path length. Optional, defaults to true. 3535 3536``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3537 Sends all traffic from the guest to a remote host over UDP. 3538 3539 ``host`` specifies the remote host to connect to. If not specified 3540 it defaults to ``localhost``. 3541 3542 ``port`` specifies the port on the remote host to connect to. 3543 ``port`` is required. 3544 3545 ``localaddr`` specifies the local address to bind to. If not 3546 specified it defaults to ``0.0.0.0``. 3547 3548 ``localport`` specifies the local port to bind to. If not specified 3549 any available local port will be used. 3550 3551 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3552 If neither is specified the device may use either protocol. 3553 3554``-chardev msmouse,id=id`` 3555 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3556 does not take any options. 3557 3558``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3559 Connect to a QEMU text console. ``vc`` may optionally be given a 3560 specific size. 3561 3562 ``width`` and ``height`` specify the width and height respectively 3563 of the console, in pixels. 3564 3565 ``cols`` and ``rows`` specify that the console be sized to fit a 3566 text console with the given dimensions. 3567 3568``-chardev ringbuf,id=id[,size=size]`` 3569 Create a ring buffer with fixed size ``size``. size must be a power 3570 of two and defaults to ``64K``. 3571 3572``-chardev file,id=id,path=path`` 3573 Log all traffic received from the guest to a file. 3574 3575 ``path`` specifies the path of the file to be opened. This file will 3576 be created if it does not already exist, and overwritten if it does. 3577 ``path`` is required. 3578 3579``-chardev pipe,id=id,path=path`` 3580 Create a two-way connection to the guest. The behaviour differs 3581 slightly between Windows hosts and other hosts: 3582 3583 On Windows, a single duplex pipe will be created at 3584 ``\\.pipe\path``. 3585 3586 On other hosts, 2 pipes will be created called ``path.in`` and 3587 ``path.out``. Data written to ``path.in`` will be received by the 3588 guest. Data written by the guest can be read from ``path.out``. QEMU 3589 will not create these fifos, and requires them to be present. 3590 3591 ``path`` forms part of the pipe path as described above. ``path`` is 3592 required. 3593 3594``-chardev console,id=id`` 3595 Send traffic from the guest to QEMU's standard output. ``console`` 3596 does not take any options. 3597 3598 ``console`` is only available on Windows hosts. 3599 3600``-chardev serial,id=id,path=path`` 3601 Send traffic from the guest to a serial device on the host. 3602 3603 On Unix hosts serial will actually accept any tty device, not only 3604 serial lines. 3605 3606 ``path`` specifies the name of the serial device to open. 3607 3608``-chardev pty,id=id`` 3609 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3610 does not take any options. 3611 3612 ``pty`` is not available on Windows hosts. 3613 3614``-chardev stdio,id=id[,signal=on|off]`` 3615 Connect to standard input and standard output of the QEMU process. 3616 3617 ``signal`` controls if signals are enabled on the terminal, that 3618 includes exiting QEMU with the key sequence Control-c. This option 3619 is enabled by default, use ``signal=off`` to disable it. 3620 3621``-chardev braille,id=id`` 3622 Connect to a local BrlAPI server. ``braille`` does not take any 3623 options. 3624 3625``-chardev tty,id=id,path=path`` 3626 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3627 and DragonFlyBSD hosts. It is an alias for ``serial``. 3628 3629 ``path`` specifies the path to the tty. ``path`` is required. 3630 3631``-chardev parallel,id=id,path=path`` 3632 \ 3633``-chardev parport,id=id,path=path`` 3634 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3635 hosts. 3636 3637 Connect to a local parallel port. 3638 3639 ``path`` specifies the path to the parallel port device. ``path`` is 3640 required. 3641 3642``-chardev spicevmc,id=id,debug=debug,name=name`` 3643 ``spicevmc`` is only available when spice support is built in. 3644 3645 ``debug`` debug level for spicevmc 3646 3647 ``name`` name of spice channel to connect to 3648 3649 Connect to a spice virtual machine channel, such as vdiport. 3650 3651``-chardev spiceport,id=id,debug=debug,name=name`` 3652 ``spiceport`` is only available when spice support is built in. 3653 3654 ``debug`` debug level for spicevmc 3655 3656 ``name`` name of spice port to connect to 3657 3658 Connect to a spice port, allowing a Spice client to handle the 3659 traffic identified by a name (preferably a fqdn). 3660ERST 3661 3662DEFHEADING() 3663 3664#ifdef CONFIG_TPM 3665DEFHEADING(TPM device options:) 3666 3667DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3668 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3669 " use path to provide path to a character device; default is /dev/tpm0\n" 3670 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3671 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3672 "-tpmdev emulator,id=id,chardev=dev\n" 3673 " configure the TPM device using chardev backend\n", 3674 QEMU_ARCH_ALL) 3675SRST 3676The general form of a TPM device option is: 3677 3678``-tpmdev backend,id=id[,options]`` 3679 The specific backend type will determine the applicable options. The 3680 ``-tpmdev`` option creates the TPM backend and requires a 3681 ``-device`` option that specifies the TPM frontend interface model. 3682 3683 Use ``-tpmdev help`` to print all available TPM backend types. 3684 3685The available backends are: 3686 3687``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3688 (Linux-host only) Enable access to the host's TPM using the 3689 passthrough driver. 3690 3691 ``path`` specifies the path to the host's TPM device, i.e., on a 3692 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3693 default ``/dev/tpm0`` is used. 3694 3695 ``cancel-path`` specifies the path to the host TPM device's sysfs 3696 entry allowing for cancellation of an ongoing TPM command. 3697 ``cancel-path`` is optional and by default QEMU will search for the 3698 sysfs entry to use. 3699 3700 Some notes about using the host's TPM with the passthrough driver: 3701 3702 The TPM device accessed by the passthrough driver must not be used 3703 by any other application on the host. 3704 3705 Since the host's firmware (BIOS/UEFI) has already initialized the 3706 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3707 the TPM again and may therefore not show a TPM-specific menu that 3708 would otherwise allow the user to configure the TPM, e.g., allow the 3709 user to enable/disable or activate/deactivate the TPM. Further, if 3710 TPM ownership is released from within a VM then the host's TPM will 3711 get disabled and deactivated. To enable and activate the TPM again 3712 afterwards, the host has to be rebooted and the user is required to 3713 enter the firmware's menu to enable and activate the TPM. If the TPM 3714 is left disabled and/or deactivated most TPM commands will fail. 3715 3716 To create a passthrough TPM use the following two options: 3717 3718 :: 3719 3720 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3721 3722 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3723 ``tpmdev=tpm0`` in the device option. 3724 3725``-tpmdev emulator,id=id,chardev=dev`` 3726 (Linux-host only) Enable access to a TPM emulator using Unix domain 3727 socket based chardev backend. 3728 3729 ``chardev`` specifies the unique ID of a character device backend 3730 that provides connection to the software TPM server. 3731 3732 To create a TPM emulator backend device with chardev socket backend: 3733 3734 :: 3735 3736 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3737ERST 3738 3739DEFHEADING() 3740 3741#endif 3742 3743DEFHEADING(Boot Image or Kernel specific:) 3744SRST 3745There are broadly 4 ways you can boot a system with QEMU. 3746 3747 - specify a firmware and let it control finding a kernel 3748 - specify a firmware and pass a hint to the kernel to boot 3749 - direct kernel image boot 3750 - manually load files into the guest's address space 3751 3752The third method is useful for quickly testing kernels but as there is 3753no firmware to pass configuration information to the kernel the 3754hardware must either be probeable, the kernel built for the exact 3755configuration or passed some configuration data (e.g. a DTB blob) 3756which tells the kernel what drivers it needs. This exact details are 3757often hardware specific. 3758 3759The final method is the most generic way of loading images into the 3760guest address space and used mostly for ``bare metal`` type 3761development where the reset vectors of the processor are taken into 3762account. 3763 3764ERST 3765 3766SRST 3767 3768For x86 machines and some other architectures ``-bios`` will generally 3769do the right thing with whatever it is given. For other machines the 3770more strict ``-pflash`` option needs an image that is sized for the 3771flash device for the given machine type. 3772 3773Please see the :ref:`system-targets-ref` section of the manual for 3774more detailed documentation. 3775 3776ERST 3777 3778DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3779 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3780SRST 3781``-bios file`` 3782 Set the filename for the BIOS. 3783ERST 3784 3785DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3786 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3787SRST 3788``-pflash file`` 3789 Use file as a parallel flash image. 3790ERST 3791 3792SRST 3793 3794The kernel options were designed to work with Linux kernels although 3795other things (like hypervisors) can be packaged up as a kernel 3796executable image. The exact format of a executable image is usually 3797architecture specific. 3798 3799The way in which the kernel is started (what address it is loaded at, 3800what if any information is passed to it via CPU registers, the state 3801of the hardware when it is started, and so on) is also architecture 3802specific. Typically it follows the specification laid down by the 3803Linux kernel for how kernels for that architecture must be started. 3804 3805ERST 3806 3807DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3808 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3809SRST 3810``-kernel bzImage`` 3811 Use bzImage as kernel image. The kernel can be either a Linux kernel 3812 or in multiboot format. 3813ERST 3814 3815DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3816 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3817SRST 3818``-append cmdline`` 3819 Use cmdline as kernel command line 3820ERST 3821 3822DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3823 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3824SRST 3825``-initrd file`` 3826 Use file as initial ram disk. 3827 3828``-initrd "file1 arg=foo,file2"`` 3829 This syntax is only available with multiboot. 3830 3831 Use file1 and file2 as modules and pass arg=foo as parameter to the 3832 first module. 3833ERST 3834 3835DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3836 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3837SRST 3838``-dtb file`` 3839 Use file as a device tree binary (dtb) image and pass it to the 3840 kernel on boot. 3841ERST 3842 3843SRST 3844 3845Finally you can also manually load images directly into the address 3846space of the guest. This is most useful for developers who already 3847know the layout of their guest and take care to ensure something sane 3848will happen when the reset vector executes. 3849 3850The generic loader can be invoked by using the loader device: 3851 3852``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3853 3854there is also the guest loader which operates in a similar way but 3855tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3856the guest image is: 3857 3858``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3859 3860ERST 3861 3862DEFHEADING() 3863 3864DEFHEADING(Debug/Expert options:) 3865 3866DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3867 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3868 " Policy for handling deprecated management interfaces\n" 3869 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3870 " Policy for handling unstable management interfaces\n", 3871 QEMU_ARCH_ALL) 3872SRST 3873``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3874 Set policy for handling deprecated management interfaces (experimental): 3875 3876 ``deprecated-input=accept`` (default) 3877 Accept deprecated commands and arguments 3878 ``deprecated-input=reject`` 3879 Reject deprecated commands and arguments 3880 ``deprecated-input=crash`` 3881 Crash on deprecated commands and arguments 3882 ``deprecated-output=accept`` (default) 3883 Emit deprecated command results and events 3884 ``deprecated-output=hide`` 3885 Suppress deprecated command results and events 3886 3887 Limitation: covers only syntactic aspects of QMP. 3888 3889``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3890 Set policy for handling unstable management interfaces (experimental): 3891 3892 ``unstable-input=accept`` (default) 3893 Accept unstable commands and arguments 3894 ``unstable-input=reject`` 3895 Reject unstable commands and arguments 3896 ``unstable-input=crash`` 3897 Crash on unstable commands and arguments 3898 ``unstable-output=accept`` (default) 3899 Emit unstable command results and events 3900 ``unstable-output=hide`` 3901 Suppress unstable command results and events 3902 3903 Limitation: covers only syntactic aspects of QMP. 3904ERST 3905 3906DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3907 "-fw_cfg [name=]<name>,file=<file>\n" 3908 " add named fw_cfg entry with contents from file\n" 3909 "-fw_cfg [name=]<name>,string=<str>\n" 3910 " add named fw_cfg entry with contents from string\n", 3911 QEMU_ARCH_ALL) 3912SRST 3913``-fw_cfg [name=]name,file=file`` 3914 Add named fw\_cfg entry with contents from file file. 3915 3916``-fw_cfg [name=]name,string=str`` 3917 Add named fw\_cfg entry with contents from string str. 3918 3919 The terminating NUL character of the contents of str will not be 3920 included as part of the fw\_cfg item data. To insert contents with 3921 embedded NUL characters, you have to use the file parameter. 3922 3923 The fw\_cfg entries are passed by QEMU through to the guest. 3924 3925 Example: 3926 3927 :: 3928 3929 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3930 3931 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3932 from ./my\_blob.bin. 3933ERST 3934 3935DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3936 "-serial dev redirect the serial port to char device 'dev'\n", 3937 QEMU_ARCH_ALL) 3938SRST 3939``-serial dev`` 3940 Redirect the virtual serial port to host character device dev. The 3941 default device is ``vc`` in graphical mode and ``stdio`` in non 3942 graphical mode. 3943 3944 This option can be used several times to simulate up to 4 serial 3945 ports. 3946 3947 Use ``-serial none`` to disable all serial ports. 3948 3949 Available character devices are: 3950 3951 ``vc[:WxH]`` 3952 Virtual console. Optionally, a width and height can be given in 3953 pixel with 3954 3955 :: 3956 3957 vc:800x600 3958 3959 It is also possible to specify width or height in characters: 3960 3961 :: 3962 3963 vc:80Cx24C 3964 3965 ``pty`` 3966 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3967 3968 ``none`` 3969 No device is allocated. 3970 3971 ``null`` 3972 void device 3973 3974 ``chardev:id`` 3975 Use a named character device defined with the ``-chardev`` 3976 option. 3977 3978 ``/dev/XXX`` 3979 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3980 port parameters are set according to the emulated ones. 3981 3982 ``/dev/parportN`` 3983 [Linux only, parallel port only] Use host parallel port N. 3984 Currently SPP and EPP parallel port features can be used. 3985 3986 ``file:filename`` 3987 Write output to filename. No character can be read. 3988 3989 ``stdio`` 3990 [Unix only] standard input/output 3991 3992 ``pipe:filename`` 3993 name pipe filename 3994 3995 ``COMn`` 3996 [Windows only] Use host serial port n 3997 3998 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3999 This implements UDP Net Console. When remote\_host or src\_ip 4000 are not specified they default to ``0.0.0.0``. When not using a 4001 specified src\_port a random port is automatically chosen. 4002 4003 If you just want a simple readonly console you can use 4004 ``netcat`` or ``nc``, by starting QEMU with: 4005 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4006 QEMU writes something to that port it will appear in the 4007 netconsole session. 4008 4009 If you plan to send characters back via netconsole or you want 4010 to stop and start QEMU a lot of times, you should have QEMU use 4011 the same source port each time by using something like ``-serial 4012 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4013 version of netcat which can listen to a TCP port and send and 4014 receive characters via udp. If you have a patched version of 4015 netcat which activates telnet remote echo and single char 4016 transfer, then you can use the following options to set up a 4017 netcat redirector to allow telnet on port 5555 to access the 4018 QEMU port. 4019 4020 ``QEMU Options:`` 4021 -serial udp::4555@:4556 4022 4023 ``netcat options:`` 4024 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4025 4026 ``telnet options:`` 4027 localhost 5555 4028 4029 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4030 The TCP Net Console has two modes of operation. It can send the 4031 serial I/O to a location or wait for a connection from a 4032 location. By default the TCP Net Console is sent to host at the 4033 port. If you use the ``server=on`` option QEMU will wait for a client 4034 socket application to connect to the port before continuing, 4035 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4036 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4037 option only applies if ``server=no`` is set, if the connection goes 4038 down it will attempt to reconnect at the given interval. If host 4039 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4040 time is accepted. You can use ``telnet=on`` to connect to the 4041 corresponding character device. 4042 4043 ``Example to send tcp console to 192.168.0.2 port 4444`` 4044 -serial tcp:192.168.0.2:4444 4045 4046 ``Example to listen and wait on port 4444 for connection`` 4047 -serial tcp::4444,server=on 4048 4049 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4050 -serial tcp:192.168.0.100:4444,server=on,wait=off 4051 4052 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4053 The telnet protocol is used instead of raw tcp sockets. The 4054 options work the same as if you had specified ``-serial tcp``. 4055 The difference is that the port acts like a telnet server or 4056 client using telnet option negotiation. This will also allow you 4057 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4058 supports sending the break sequence. Typically in unix telnet 4059 you do it with Control-] and then type "send break" followed by 4060 pressing the enter key. 4061 4062 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4063 The WebSocket protocol is used instead of raw tcp socket. The 4064 port acts as a WebSocket server. Client mode is not supported. 4065 4066 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4067 A unix domain socket is used instead of a tcp socket. The option 4068 works the same as if you had specified ``-serial tcp`` except 4069 the unix domain socket path is used for connections. 4070 4071 ``mon:dev_string`` 4072 This is a special option to allow the monitor to be multiplexed 4073 onto another serial port. The monitor is accessed with key 4074 sequence of Control-a and then pressing c. dev\_string should be 4075 any one of the serial devices specified above. An example to 4076 multiplex the monitor onto a telnet server listening on port 4077 4444 would be: 4078 4079 ``-serial mon:telnet::4444,server=on,wait=off`` 4080 4081 When the monitor is multiplexed to stdio in this way, Ctrl+C 4082 will not terminate QEMU any more but will be passed to the guest 4083 instead. 4084 4085 ``braille`` 4086 Braille device. This will use BrlAPI to display the braille 4087 output on a real or fake device. 4088 4089 ``msmouse`` 4090 Three button serial mouse. Configure the guest to use Microsoft 4091 protocol. 4092ERST 4093 4094DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4095 "-parallel dev redirect the parallel port to char device 'dev'\n", 4096 QEMU_ARCH_ALL) 4097SRST 4098``-parallel dev`` 4099 Redirect the virtual parallel port to host device dev (same devices 4100 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4101 to use hardware devices connected on the corresponding host parallel 4102 port. 4103 4104 This option can be used several times to simulate up to 3 parallel 4105 ports. 4106 4107 Use ``-parallel none`` to disable all parallel ports. 4108ERST 4109 4110DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4111 "-monitor dev redirect the monitor to char device 'dev'\n", 4112 QEMU_ARCH_ALL) 4113SRST 4114``-monitor dev`` 4115 Redirect the monitor to host device dev (same devices as the serial 4116 port). The default device is ``vc`` in graphical mode and ``stdio`` 4117 in non graphical mode. Use ``-monitor none`` to disable the default 4118 monitor. 4119ERST 4120DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4121 "-qmp dev like -monitor but opens in 'control' mode\n", 4122 QEMU_ARCH_ALL) 4123SRST 4124``-qmp dev`` 4125 Like -monitor but opens in 'control' mode. 4126ERST 4127DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4128 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4129 QEMU_ARCH_ALL) 4130SRST 4131``-qmp-pretty dev`` 4132 Like -qmp but uses pretty JSON formatting. 4133ERST 4134 4135DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4136 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4137SRST 4138``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4139 Setup monitor on chardev name. ``mode=control`` configures 4140 a QMP monitor (a JSON RPC-style protocol) and it is not the 4141 same as HMP, the human monitor that has a "(qemu)" prompt. 4142 ``pretty`` is only valid when ``mode=control``, 4143 turning on JSON pretty printing to ease 4144 human reading and debugging. 4145ERST 4146 4147DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4148 "-debugcon dev redirect the debug console to char device 'dev'\n", 4149 QEMU_ARCH_ALL) 4150SRST 4151``-debugcon dev`` 4152 Redirect the debug console to host device dev (same devices as the 4153 serial port). The debug console is an I/O port which is typically 4154 port 0xe9; writing to that I/O port sends output to this device. The 4155 default device is ``vc`` in graphical mode and ``stdio`` in non 4156 graphical mode. 4157ERST 4158 4159DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4160 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4161SRST 4162``-pidfile file`` 4163 Store the QEMU process PID in file. It is useful if you launch QEMU 4164 from a script. 4165ERST 4166 4167DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4168 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4169SRST 4170``-singlestep`` 4171 Run the emulation in single step mode. 4172ERST 4173 4174DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4175 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4176 QEMU_ARCH_ALL) 4177SRST 4178``--preconfig`` 4179 Pause QEMU for interactive configuration before the machine is 4180 created, which allows querying and configuring properties that will 4181 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4182 exit the preconfig state and move to the next state (i.e. run guest 4183 if -S isn't used or pause the second time if -S is used). This 4184 option is experimental. 4185ERST 4186 4187DEF("S", 0, QEMU_OPTION_S, \ 4188 "-S freeze CPU at startup (use 'c' to start execution)\n", 4189 QEMU_ARCH_ALL) 4190SRST 4191``-S`` 4192 Do not start CPU at startup (you must type 'c' in the monitor). 4193ERST 4194 4195DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4196 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4197 " run qemu with overcommit hints\n" 4198 " mem-lock=on|off controls memory lock support (default: off)\n" 4199 " cpu-pm=on|off controls cpu power management (default: off)\n", 4200 QEMU_ARCH_ALL) 4201SRST 4202``-overcommit mem-lock=on|off`` 4203 \ 4204``-overcommit cpu-pm=on|off`` 4205 Run qemu with hints about host resource overcommit. The default is 4206 to assume that host overcommits all resources. 4207 4208 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4209 (disabled by default). This works when host memory is not 4210 overcommitted and reduces the worst-case latency for guest. 4211 4212 Guest ability to manage power state of host cpus (increasing latency 4213 for other processes on the same host cpu, but decreasing latency for 4214 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4215 works best when host CPU is not overcommitted. When used, host 4216 estimates of CPU cycle and power utilization will be incorrect, not 4217 taking into account guest idle time. 4218ERST 4219 4220DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4221 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4222 " the guest without waiting for gdb to connect; use -S too\n" 4223 " if you want it to not start execution.)\n", 4224 QEMU_ARCH_ALL) 4225SRST 4226``-gdb dev`` 4227 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4228 in the System Emulation Users Guide). Note that this option does not pause QEMU 4229 execution -- if you want QEMU to not start the guest until you 4230 connect with gdb and issue a ``continue`` command, you will need to 4231 also pass the ``-S`` option to QEMU. 4232 4233 The most usual configuration is to listen on a local TCP socket:: 4234 4235 -gdb tcp::3117 4236 4237 but you can specify other backends; UDP, pseudo TTY, or even stdio 4238 are all reasonable use cases. For example, a stdio connection 4239 allows you to start QEMU from within gdb and establish the 4240 connection via a pipe: 4241 4242 .. parsed-literal:: 4243 4244 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4245ERST 4246 4247DEF("s", 0, QEMU_OPTION_s, \ 4248 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4249 QEMU_ARCH_ALL) 4250SRST 4251``-s`` 4252 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4253 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4254ERST 4255 4256DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4257 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4258 QEMU_ARCH_ALL) 4259SRST 4260``-d item1[,...]`` 4261 Enable logging of specified items. Use '-d help' for a list of log 4262 items. 4263ERST 4264 4265DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4266 "-D logfile output log to logfile (default stderr)\n", 4267 QEMU_ARCH_ALL) 4268SRST 4269``-D logfile`` 4270 Output log in logfile instead of to stderr 4271ERST 4272 4273DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4274 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4275 QEMU_ARCH_ALL) 4276SRST 4277``-dfilter range1[,...]`` 4278 Filter debug output to that relevant to a range of target addresses. 4279 The filter spec can be either start+size, start-size or start..end 4280 where start end and size are the addresses and sizes required. For 4281 example: 4282 4283 :: 4284 4285 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4286 4287 Will dump output for any code in the 0x1000 sized block starting at 4288 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4289 another 0x1000 sized block starting at 0xffffffc00005f000. 4290ERST 4291 4292DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4293 "-seed number seed the pseudo-random number generator\n", 4294 QEMU_ARCH_ALL) 4295SRST 4296``-seed number`` 4297 Force the guest to use a deterministic pseudo-random number 4298 generator, seeded with number. This does not affect crypto routines 4299 within the host. 4300ERST 4301 4302DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4303 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4304 QEMU_ARCH_ALL) 4305SRST 4306``-L path`` 4307 Set the directory for the BIOS, VGA BIOS and keymaps. 4308 4309 To list all the data directories, use ``-L help``. 4310ERST 4311 4312DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4313 "-enable-kvm enable KVM full virtualization support\n", 4314 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4315 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4316SRST 4317``-enable-kvm`` 4318 Enable KVM full virtualization support. This option is only 4319 available if KVM support is enabled when compiling. 4320ERST 4321 4322DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4323 "-xen-domid id specify xen guest domain id\n", 4324 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4325DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4326 "-xen-attach attach to existing xen domain\n" 4327 " libxl will use this when starting QEMU\n", 4328 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4329DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4330 "-xen-domid-restrict restrict set of available xen operations\n" 4331 " to specified domain id. (Does not affect\n" 4332 " xenpv machine type).\n", 4333 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4334SRST 4335``-xen-domid id`` 4336 Specify xen guest domain id (XEN only). 4337 4338``-xen-attach`` 4339 Attach to existing xen domain. libxl will use this when starting 4340 QEMU (XEN only). Restrict set of available xen operations to 4341 specified domain id (XEN only). 4342ERST 4343 4344DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4345 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4346SRST 4347``-no-reboot`` 4348 Exit instead of rebooting. 4349ERST 4350 4351DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4352 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4353SRST 4354``-no-shutdown`` 4355 Don't exit QEMU on guest shutdown, but instead only stop the 4356 emulation. This allows for instance switching to monitor to commit 4357 changes to the disk image. 4358ERST 4359 4360DEF("action", HAS_ARG, QEMU_OPTION_action, 4361 "-action reboot=reset|shutdown\n" 4362 " action when guest reboots [default=reset]\n" 4363 "-action shutdown=poweroff|pause\n" 4364 " action when guest shuts down [default=poweroff]\n" 4365 "-action panic=pause|shutdown|exit-failure|none\n" 4366 " action when guest panics [default=shutdown]\n" 4367 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4368 " action when watchdog fires [default=reset]\n", 4369 QEMU_ARCH_ALL) 4370SRST 4371``-action event=action`` 4372 The action parameter serves to modify QEMU's default behavior when 4373 certain guest events occur. It provides a generic method for specifying the 4374 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4375 parameters. 4376 4377 Examples: 4378 4379 ``-action panic=none`` 4380 ``-action reboot=shutdown,shutdown=pause`` 4381 ``-device i6300esb -action watchdog=pause`` 4382 4383ERST 4384 4385DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4386 "-loadvm [tag|id]\n" \ 4387 " start right away with a saved state (loadvm in monitor)\n", 4388 QEMU_ARCH_ALL) 4389SRST 4390``-loadvm file`` 4391 Start right away with a saved state (``loadvm`` in monitor) 4392ERST 4393 4394#ifndef _WIN32 4395DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4396 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4397#endif 4398SRST 4399``-daemonize`` 4400 Daemonize the QEMU process after initialization. QEMU will not 4401 detach from standard IO until it is ready to receive connections on 4402 any of its devices. This option is a useful way for external 4403 programs to launch QEMU without having to cope with initialization 4404 race conditions. 4405ERST 4406 4407DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4408 "-option-rom rom load a file, rom, into the option ROM space\n", 4409 QEMU_ARCH_ALL) 4410SRST 4411``-option-rom file`` 4412 Load the contents of file as an option ROM. This option is useful to 4413 load things like EtherBoot. 4414ERST 4415 4416DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4417 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4418 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4419 QEMU_ARCH_ALL) 4420 4421SRST 4422``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4423 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4424 the current UTC or local time, respectively. ``localtime`` is 4425 required for correct date in MS-DOS or Windows. To start at a 4426 specific point in time, provide datetime in the format 4427 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4428 4429 By default the RTC is driven by the host system time. This allows 4430 using of the RTC as accurate reference clock inside the guest, 4431 specifically if the host time is smoothly following an accurate 4432 external reference clock, e.g. via NTP. If you want to isolate the 4433 guest time from the host, you can set ``clock`` to ``rt`` instead, 4434 which provides a host monotonic clock if host support it. To even 4435 prevent the RTC from progressing during suspension, you can set 4436 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4437 recommended especially in icount mode in order to preserve 4438 determinism; however, note that in icount mode the speed of the 4439 virtual clock is variable and can in general differ from the host 4440 clock. 4441 4442 Enable ``driftfix`` (i386 targets only) if you experience time drift 4443 problems, specifically with Windows' ACPI HAL. This option will try 4444 to figure out how many timer interrupts were not processed by the 4445 Windows guest and will re-inject them. 4446ERST 4447 4448DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4449 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4450 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4451 " instruction, enable aligning the host and virtual clocks\n" \ 4452 " or disable real time cpu sleeping, and optionally enable\n" \ 4453 " record-and-replay mode\n", QEMU_ARCH_ALL) 4454SRST 4455``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4456 Enable virtual instruction counter. The virtual cpu will execute one 4457 instruction every 2^N ns of virtual time. If ``auto`` is specified 4458 then the virtual cpu speed will be automatically adjusted to keep 4459 virtual time within a few seconds of real time. 4460 4461 Note that while this option can give deterministic behavior, it does 4462 not provide cycle accurate emulation. Modern CPUs contain 4463 superscalar out of order cores with complex cache hierarchies. The 4464 number of instructions executed often has little or no correlation 4465 with actual performance. 4466 4467 When the virtual cpu is sleeping, the virtual time will advance at 4468 default speed unless ``sleep=on`` is specified. With 4469 ``sleep=on``, the virtual time will jump to the next timer 4470 deadline instantly whenever the virtual cpu goes to sleep mode and 4471 will not advance if no timer is enabled. This behavior gives 4472 deterministic execution times from the guest point of view. 4473 The default if icount is enabled is ``sleep=off``. 4474 ``sleep=on`` cannot be used together with either ``shift=auto`` 4475 or ``align=on``. 4476 4477 ``align=on`` will activate the delay algorithm which will try to 4478 synchronise the host clock and the virtual clock. The goal is to 4479 have a guest running at the real frequency imposed by the shift 4480 option. Whenever the guest clock is behind the host clock and if 4481 ``align=on`` is specified then we print a message to the user to 4482 inform about the delay. Currently this option does not work when 4483 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4484 shift values for which the guest clock runs ahead of the host clock. 4485 Typically this happens when the shift value is high (how high 4486 depends on the host machine). The default if icount is enabled 4487 is ``align=off``. 4488 4489 When the ``rr`` option is specified deterministic record/replay is 4490 enabled. The ``rrfile=`` option must also be provided to 4491 specify the path to the replay log. In record mode data is written 4492 to this file, and in replay mode it is read back. 4493 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4494 name. In record mode, a new VM snapshot with the given name is created 4495 at the start of execution recording. In replay mode this option 4496 specifies the snapshot name used to load the initial VM state. 4497ERST 4498 4499DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4500 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4501 " action when watchdog fires [default=reset]\n", 4502 QEMU_ARCH_ALL) 4503SRST 4504``-watchdog-action action`` 4505 The action controls what QEMU will do when the watchdog timer 4506 expires. The default is ``reset`` (forcefully reset the guest). 4507 Other possible actions are: ``shutdown`` (attempt to gracefully 4508 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4509 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4510 guest), ``debug`` (print a debug message and continue), or ``none`` 4511 (do nothing). 4512 4513 Note that the ``shutdown`` action requires that the guest responds 4514 to ACPI signals, which it may not be able to do in the sort of 4515 situations where the watchdog would have expired, and thus 4516 ``-watchdog-action shutdown`` is not recommended for production use. 4517 4518 Examples: 4519 4520 ``-device i6300esb -watchdog-action pause`` 4521 4522ERST 4523 4524DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4525 "-echr chr set terminal escape character instead of ctrl-a\n", 4526 QEMU_ARCH_ALL) 4527SRST 4528``-echr numeric_ascii_value`` 4529 Change the escape character used for switching to the monitor when 4530 using monitor and serial sharing. The default is ``0x01`` when using 4531 the ``-nographic`` option. ``0x01`` is equal to pressing 4532 ``Control-a``. You can select a different character from the ascii 4533 control keys where 1 through 26 map to Control-a through Control-z. 4534 For instance you could use the either of the following to change the 4535 escape character to Control-t. 4536 4537 ``-echr 0x14``; \ ``-echr 20`` 4538 4539ERST 4540 4541DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4542 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4543 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4544 "-incoming unix:socketpath\n" \ 4545 " prepare for incoming migration, listen on\n" \ 4546 " specified protocol and socket address\n" \ 4547 "-incoming fd:fd\n" \ 4548 "-incoming exec:cmdline\n" \ 4549 " accept incoming migration on given file descriptor\n" \ 4550 " or from given external command\n" \ 4551 "-incoming defer\n" \ 4552 " wait for the URI to be specified via migrate_incoming\n", 4553 QEMU_ARCH_ALL) 4554SRST 4555``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4556 \ 4557``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4558 Prepare for incoming migration, listen on a given tcp port. 4559 4560``-incoming unix:socketpath`` 4561 Prepare for incoming migration, listen on a given unix socket. 4562 4563``-incoming fd:fd`` 4564 Accept incoming migration from a given filedescriptor. 4565 4566``-incoming exec:cmdline`` 4567 Accept incoming migration as an output from specified external 4568 command. 4569 4570``-incoming defer`` 4571 Wait for the URI to be specified via migrate\_incoming. The monitor 4572 can be used to change settings (such as migration parameters) prior 4573 to issuing the migrate\_incoming to allow the migration to begin. 4574ERST 4575 4576DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4577 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4578SRST 4579``-only-migratable`` 4580 Only allow migratable devices. Devices will not be allowed to enter 4581 an unmigratable state. 4582ERST 4583 4584DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4585 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4586SRST 4587``-nodefaults`` 4588 Don't create default devices. Normally, QEMU sets the default 4589 devices like serial port, parallel port, virtual console, monitor 4590 device, VGA adapter, floppy and CD-ROM drive and others. The 4591 ``-nodefaults`` option will disable all those default devices. 4592ERST 4593 4594#ifndef _WIN32 4595DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4596 "-chroot dir chroot to dir just before starting the VM\n", 4597 QEMU_ARCH_ALL) 4598#endif 4599SRST 4600``-chroot dir`` 4601 Immediately before starting guest execution, chroot to the specified 4602 directory. Especially useful in combination with -runas. 4603ERST 4604 4605#ifndef _WIN32 4606DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4607 "-runas user change to user id user just before starting the VM\n" \ 4608 " user can be numeric uid:gid instead\n", 4609 QEMU_ARCH_ALL) 4610#endif 4611SRST 4612``-runas user`` 4613 Immediately before starting guest execution, drop root privileges, 4614 switching to the specified user. 4615ERST 4616 4617DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4618 "-prom-env variable=value\n" 4619 " set OpenBIOS nvram variables\n", 4620 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4621SRST 4622``-prom-env variable=value`` 4623 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4624 4625 :: 4626 4627 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4628 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4629 4630 :: 4631 4632 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4633 -prom-env 'boot-device=hd:2,\yaboot' \ 4634 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4635ERST 4636DEF("semihosting", 0, QEMU_OPTION_semihosting, 4637 "-semihosting semihosting mode\n", 4638 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4639 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4640SRST 4641``-semihosting`` 4642 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4643 4644 Note that this allows guest direct access to the host filesystem, so 4645 should only be used with a trusted guest OS. 4646 4647 See the -semihosting-config option documentation for further 4648 information about the facilities this enables. 4649ERST 4650DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4651 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4652 " semihosting configuration\n", 4653QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4654QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4655SRST 4656``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4657 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4658 only). 4659 4660 Note that this allows guest direct access to the host filesystem, so 4661 should only be used with a trusted guest OS. 4662 4663 On Arm this implements the standard semihosting API, version 2.0. 4664 4665 On M68K this implements the "ColdFire GDB" interface used by 4666 libgloss. 4667 4668 Xtensa semihosting provides basic file IO calls, such as 4669 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4670 linux platform "sim" use this interface. 4671 4672 On RISC-V this implements the standard semihosting API, version 0.2. 4673 4674 ``target=native|gdb|auto`` 4675 Defines where the semihosting calls will be addressed, to QEMU 4676 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4677 means ``gdb`` during debug sessions and ``native`` otherwise. 4678 4679 ``chardev=str1`` 4680 Send the output to a chardev backend output for native or auto 4681 output when not in gdb 4682 4683 ``userspace=on|off`` 4684 Allows code running in guest userspace to access the semihosting 4685 interface. The default is that only privileged guest code can 4686 make semihosting calls. Note that setting ``userspace=on`` should 4687 only be used if all guest code is trusted (for example, in 4688 bare-metal test case code). 4689 4690 ``arg=str1,arg=str2,...`` 4691 Allows the user to pass input arguments, and can be used 4692 multiple times to build up a list. The old-style 4693 ``-kernel``/``-append`` method of passing a command line is 4694 still supported for backward compatibility. If both the 4695 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4696 specified, the former is passed to semihosting as it always 4697 takes precedence. 4698ERST 4699DEF("old-param", 0, QEMU_OPTION_old_param, 4700 "-old-param old param mode\n", QEMU_ARCH_ARM) 4701SRST 4702``-old-param`` 4703 Old param mode (ARM only). 4704ERST 4705 4706DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4707 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4708 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4709 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4710 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4711 " by the kernel, but typically no longer used by modern\n" \ 4712 " C library implementations.\n" \ 4713 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4714 " to elevate privileges using set*uid|gid system calls.\n" \ 4715 " The value 'children' will deny set*uid|gid system calls for\n" \ 4716 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4717 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4718 " blocking *fork and execve\n" \ 4719 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4720 QEMU_ARCH_ALL) 4721SRST 4722``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4723 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4724 filtering and 'off' will disable it. The default is 'off'. 4725 4726 ``obsolete=string`` 4727 Enable Obsolete system calls 4728 4729 ``elevateprivileges=string`` 4730 Disable set\*uid\|gid system calls 4731 4732 ``spawn=string`` 4733 Disable \*fork and execve 4734 4735 ``resourcecontrol=string`` 4736 Disable process affinity and schedular priority 4737ERST 4738 4739DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4740 "-readconfig <file>\n" 4741 " read config file\n", QEMU_ARCH_ALL) 4742SRST 4743``-readconfig file`` 4744 Read device configuration from file. This approach is useful when 4745 you want to spawn QEMU process with many command line options but 4746 you don't want to exceed the command line character limit. 4747ERST 4748 4749DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4750 "-no-user-config\n" 4751 " do not load default user-provided config files at startup\n", 4752 QEMU_ARCH_ALL) 4753SRST 4754``-no-user-config`` 4755 The ``-no-user-config`` option makes QEMU not load any of the 4756 user-provided config files on sysconfdir. 4757ERST 4758 4759DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4760 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4761 " specify tracing options\n", 4762 QEMU_ARCH_ALL) 4763SRST 4764``-trace [[enable=]pattern][,events=file][,file=file]`` 4765 .. include:: ../qemu-option-trace.rst.inc 4766 4767ERST 4768DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4769 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4770 " load a plugin\n", 4771 QEMU_ARCH_ALL) 4772SRST 4773``-plugin file=file[,argname=argvalue]`` 4774 Load a plugin. 4775 4776 ``file=file`` 4777 Load the given plugin from a shared library file. 4778 4779 ``argname=argvalue`` 4780 Argument passed to the plugin. (Can be given multiple times.) 4781ERST 4782 4783HXCOMM Internal use 4784DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4785DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4786 4787#ifdef __linux__ 4788DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4789 "-async-teardown enable asynchronous teardown\n", 4790 QEMU_ARCH_ALL) 4791#endif 4792SRST 4793``-async-teardown`` 4794 Enable asynchronous teardown. A new process called "cleanup/<QEMU_PID>" 4795 will be created at startup sharing the address space with the main qemu 4796 process, using clone. It will wait for the main qemu process to 4797 terminate completely, and then exit. 4798 This allows qemu to terminate very quickly even if the guest was 4799 huge, leaving the teardown of the address space to the cleanup 4800 process. Since the cleanup process shares the same cgroups as the 4801 main qemu process, accounting is performed correctly. This only 4802 works if the cleanup process is not forcefully killed with SIGKILL 4803 before the main qemu process has terminated completely. 4804ERST 4805 4806DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4807 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4808 " control error message format\n" 4809 " timestamp=on enables timestamps (default: off)\n" 4810 " guest-name=on enables guest name prefix but only if\n" 4811 " -name guest option is set (default: off)\n", 4812 QEMU_ARCH_ALL) 4813SRST 4814``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4815 Control error message format. 4816 4817 ``timestamp=on|off`` 4818 Prefix messages with a timestamp. Default is off. 4819 4820 ``guest-name=on|off`` 4821 Prefix messages with guest name but only if -name guest option is set 4822 otherwise the option is ignored. Default is off. 4823ERST 4824 4825DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4826 "-dump-vmstate <file>\n" 4827 " Output vmstate information in JSON format to file.\n" 4828 " Use the scripts/vmstate-static-checker.py file to\n" 4829 " check for possible regressions in migration code\n" 4830 " by comparing two such vmstate dumps.\n", 4831 QEMU_ARCH_ALL) 4832SRST 4833``-dump-vmstate file`` 4834 Dump json-encoded vmstate information for current machine type to 4835 file in file 4836ERST 4837 4838DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4839 "-enable-sync-profile\n" 4840 " enable synchronization profiling\n", 4841 QEMU_ARCH_ALL) 4842SRST 4843``-enable-sync-profile`` 4844 Enable synchronization profiling. 4845ERST 4846 4847DEFHEADING() 4848 4849DEFHEADING(Generic object creation:) 4850 4851DEF("object", HAS_ARG, QEMU_OPTION_object, 4852 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4853 " create a new object of type TYPENAME setting properties\n" 4854 " in the order they are specified. Note that the 'id'\n" 4855 " property must be set. These objects are placed in the\n" 4856 " '/objects' path.\n", 4857 QEMU_ARCH_ALL) 4858SRST 4859``-object typename[,prop1=value1,...]`` 4860 Create a new object of type typename setting properties in the order 4861 they are specified. Note that the 'id' property must be set. These 4862 objects are placed in the '/objects' path. 4863 4864 ``-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`` 4865 Creates a memory file backend object, which can be used to back 4866 the guest RAM with huge pages. 4867 4868 The ``id`` parameter is a unique ID that will be used to 4869 reference this memory region in other parameters, e.g. ``-numa``, 4870 ``-device nvdimm``, etc. 4871 4872 The ``size`` option provides the size of the memory region, and 4873 accepts common suffixes, e.g. ``500M``. 4874 4875 The ``mem-path`` provides the path to either a shared memory or 4876 huge page filesystem mount. 4877 4878 The ``share`` boolean option determines whether the memory 4879 region is marked as private to QEMU, or shared. The latter 4880 allows a co-operating external process to access the QEMU memory 4881 region. 4882 4883 The ``share`` is also required for pvrdma devices due to 4884 limitations in the RDMA API provided by Linux. 4885 4886 Setting share=on might affect the ability to configure NUMA 4887 bindings for the memory backend under some circumstances, see 4888 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4889 source tree for additional details. 4890 4891 Setting the ``discard-data`` boolean option to on indicates that 4892 file contents can be destroyed when QEMU exits, to avoid 4893 unnecessarily flushing data to the backing file. Note that 4894 ``discard-data`` is only an optimization, and QEMU might not 4895 discard file contents if it aborts unexpectedly or is terminated 4896 using SIGKILL. 4897 4898 The ``merge`` boolean option enables memory merge, also known as 4899 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4900 the pages for memory deduplication. 4901 4902 Setting the ``dump`` boolean option to off excludes the memory 4903 from core dumps. This feature is also known as MADV\_DONTDUMP. 4904 4905 The ``prealloc`` boolean option enables memory preallocation. 4906 4907 The ``host-nodes`` option binds the memory range to a list of 4908 NUMA host nodes. 4909 4910 The ``policy`` option sets the NUMA policy to one of the 4911 following values: 4912 4913 ``default`` 4914 default host policy 4915 4916 ``preferred`` 4917 prefer the given host node list for allocation 4918 4919 ``bind`` 4920 restrict memory allocation to the given host node list 4921 4922 ``interleave`` 4923 interleave memory allocations across the given host node 4924 list 4925 4926 The ``align`` option specifies the base address alignment when 4927 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4928 ``2M``. Some backend store specified by ``mem-path`` requires an 4929 alignment different than the default one used by QEMU, eg the 4930 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4931 such cases, users can specify the required alignment via this 4932 option. 4933 4934 The ``pmem`` option specifies whether the backing file specified 4935 by ``mem-path`` is in host persistent memory that can be 4936 accessed using the SNIA NVM programming model (e.g. Intel 4937 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4938 operations to guarantee the persistence of its own writes to 4939 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4940 migration). Also, we will map the backend-file with MAP\_SYNC 4941 flag, which ensures the file metadata is in sync for 4942 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4943 requires support from both the host kernel (since Linux kernel 4944 4.15) and the filesystem of ``mem-path`` mounted with DAX 4945 option. 4946 4947 The ``readonly`` option specifies whether the backing file is opened 4948 read-only or read-write (default). 4949 4950 ``-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`` 4951 Creates a memory backend object, which can be used to back the 4952 guest RAM. Memory backend objects offer more control than the 4953 ``-m`` option that is traditionally used to define guest RAM. 4954 Please refer to ``memory-backend-file`` for a description of the 4955 options. 4956 4957 ``-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`` 4958 Creates an anonymous memory file backend object, which allows 4959 QEMU to share the memory with an external process (e.g. when 4960 using vhost-user). The memory is allocated with memfd and 4961 optional sealing. (Linux only) 4962 4963 The ``seal`` option creates a sealed-file, that will block 4964 further resizing the memory ('on' by default). 4965 4966 The ``hugetlb`` option specify the file to be created resides in 4967 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4968 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4969 the hugetlb page size on systems that support multiple hugetlb 4970 page sizes (it must be a power of 2 value supported by the 4971 system). 4972 4973 In some versions of Linux, the ``hugetlb`` option is 4974 incompatible with the ``seal`` option (requires at least Linux 4975 4.16). 4976 4977 Please refer to ``memory-backend-file`` for a description of the 4978 other options. 4979 4980 The ``share`` boolean option is on by default with memfd. 4981 4982 ``-object rng-builtin,id=id`` 4983 Creates a random number generator backend which obtains entropy 4984 from QEMU builtin functions. The ``id`` parameter is a unique ID 4985 that will be used to reference this entropy backend from the 4986 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4987 uses this RNG backend. 4988 4989 ``-object rng-random,id=id,filename=/dev/random`` 4990 Creates a random number generator backend which obtains entropy 4991 from a device on the host. The ``id`` parameter is a unique ID 4992 that will be used to reference this entropy backend from the 4993 ``virtio-rng`` device. The ``filename`` parameter specifies 4994 which file to obtain entropy from and if omitted defaults to 4995 ``/dev/urandom``. 4996 4997 ``-object rng-egd,id=id,chardev=chardevid`` 4998 Creates a random number generator backend which obtains entropy 4999 from an external daemon running on the host. The ``id`` 5000 parameter is a unique ID that will be used to reference this 5001 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5002 parameter is the unique ID of a character device backend that 5003 provides the connection to the RNG daemon. 5004 5005 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5006 Creates a TLS anonymous credentials object, which can be used to 5007 provide TLS support on network backends. The ``id`` parameter is 5008 a unique ID which network backends will use to access the 5009 credentials. The ``endpoint`` is either ``server`` or ``client`` 5010 depending on whether the QEMU network backend that uses the 5011 credentials will be acting as a client or as a server. If 5012 ``verify-peer`` is enabled (the default) then once the handshake 5013 is completed, the peer credentials will be verified, though this 5014 is a no-op for anonymous credentials. 5015 5016 The dir parameter tells QEMU where to find the credential files. 5017 For server endpoints, this directory may contain a file 5018 dh-params.pem providing diffie-hellman parameters to use for the 5019 TLS server. If the file is missing, QEMU will generate a set of 5020 DH parameters at startup. This is a computationally expensive 5021 operation that consumes random pool entropy, so it is 5022 recommended that a persistent set of parameters be generated 5023 upfront and saved. 5024 5025 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5026 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5027 can be used to provide TLS support on network backends. The 5028 ``id`` parameter is a unique ID which network backends will use 5029 to access the credentials. The ``endpoint`` is either ``server`` 5030 or ``client`` depending on whether the QEMU network backend that 5031 uses the credentials will be acting as a client or as a server. 5032 For clients only, ``username`` is the username which will be 5033 sent to the server. If omitted it defaults to "qemu". 5034 5035 The dir parameter tells QEMU where to find the keys file. It is 5036 called "dir/keys.psk" and contains "username:key" pairs. This 5037 file can most easily be created using the GnuTLS ``psktool`` 5038 program. 5039 5040 For server endpoints, dir may also contain a file dh-params.pem 5041 providing diffie-hellman parameters to use for the TLS server. 5042 If the file is missing, QEMU will generate a set of DH 5043 parameters at startup. This is a computationally expensive 5044 operation that consumes random pool entropy, so it is 5045 recommended that a persistent set of parameters be generated up 5046 front and saved. 5047 5048 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5049 Creates a TLS anonymous credentials object, which can be used to 5050 provide TLS support on network backends. The ``id`` parameter is 5051 a unique ID which network backends will use to access the 5052 credentials. The ``endpoint`` is either ``server`` or ``client`` 5053 depending on whether the QEMU network backend that uses the 5054 credentials will be acting as a client or as a server. If 5055 ``verify-peer`` is enabled (the default) then once the handshake 5056 is completed, the peer credentials will be verified. With x509 5057 certificates, this implies that the clients must be provided 5058 with valid client certificates too. 5059 5060 The dir parameter tells QEMU where to find the credential files. 5061 For server endpoints, this directory may contain a file 5062 dh-params.pem providing diffie-hellman parameters to use for the 5063 TLS server. If the file is missing, QEMU will generate a set of 5064 DH parameters at startup. This is a computationally expensive 5065 operation that consumes random pool entropy, so it is 5066 recommended that a persistent set of parameters be generated 5067 upfront and saved. 5068 5069 For x509 certificate credentials the directory will contain 5070 further files providing the x509 certificates. The certificates 5071 must be stored in PEM format, in filenames ca-cert.pem, 5072 ca-crl.pem (optional), server-cert.pem (only servers), 5073 server-key.pem (only servers), client-cert.pem (only clients), 5074 and client-key.pem (only clients). 5075 5076 For the server-key.pem and client-key.pem files which contain 5077 sensitive private keys, it is possible to use an encrypted 5078 version by providing the passwordid parameter. This provides the 5079 ID of a previously created ``secret`` object containing the 5080 password for decryption. 5081 5082 The priority parameter allows to override the global default 5083 priority used by gnutls. This can be useful if the system 5084 administrator needs to use a weaker set of crypto priorities for 5085 QEMU without potentially forcing the weakness onto all 5086 applications. Or conversely if one wants wants a stronger 5087 default for QEMU than for all other applications, they can do 5088 this through this parameter. Its format is a gnutls priority 5089 string as described at 5090 https://gnutls.org/manual/html_node/Priority-Strings.html. 5091 5092 ``-object tls-cipher-suites,id=id,priority=priority`` 5093 Creates a TLS cipher suites object, which can be used to control 5094 the TLS cipher/protocol algorithms that applications are permitted 5095 to use. 5096 5097 The ``id`` parameter is a unique ID which frontends will use to 5098 access the ordered list of permitted TLS cipher suites from the 5099 host. 5100 5101 The ``priority`` parameter allows to override the global default 5102 priority used by gnutls. This can be useful if the system 5103 administrator needs to use a weaker set of crypto priorities for 5104 QEMU without potentially forcing the weakness onto all 5105 applications. Or conversely if one wants wants a stronger 5106 default for QEMU than for all other applications, they can do 5107 this through this parameter. Its format is a gnutls priority 5108 string as described at 5109 https://gnutls.org/manual/html_node/Priority-Strings.html. 5110 5111 An example of use of this object is to control UEFI HTTPS Boot. 5112 The tls-cipher-suites object exposes the ordered list of permitted 5113 TLS cipher suites from the host side to the guest firmware, via 5114 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5115 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5116 guest-side TLS. 5117 5118 In the following example, the priority at which the host-side policy 5119 is retrieved is given by the ``priority`` property. 5120 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5121 refer to /etc/crypto-policies/back-ends/gnutls.config. 5122 5123 .. parsed-literal:: 5124 5125 # |qemu_system| \\ 5126 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5127 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5128 5129 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5130 Interval t can't be 0, this filter batches the packet delivery: 5131 all packets arriving in a given interval on netdev netdevid are 5132 delayed until the end of the interval. Interval is in 5133 microseconds. ``status`` is optional that indicate whether the 5134 netfilter is on (enabled) or off (disabled), the default status 5135 for netfilter will be 'on'. 5136 5137 queue all\|rx\|tx is an option that can be applied to any 5138 netfilter. 5139 5140 ``all``: the filter is attached both to the receive and the 5141 transmit queue of the netdev (default). 5142 5143 ``rx``: the filter is attached to the receive queue of the 5144 netdev, where it will receive packets sent to the netdev. 5145 5146 ``tx``: the filter is attached to the transmit queue of the 5147 netdev, where it will receive packets sent by the netdev. 5148 5149 position head\|tail\|id=<id> is an option to specify where the 5150 filter should be inserted in the filter list. It can be applied 5151 to any netfilter. 5152 5153 ``head``: the filter is inserted at the head of the filter list, 5154 before any existing filters. 5155 5156 ``tail``: the filter is inserted at the tail of the filter list, 5157 behind any existing filters (default). 5158 5159 ``id=<id>``: the filter is inserted before or behind the filter 5160 specified by <id>, see the insert option below. 5161 5162 insert behind\|before is an option to specify where to insert 5163 the new filter relative to the one specified with 5164 position=id=<id>. It can be applied to any netfilter. 5165 5166 ``before``: insert before the specified filter. 5167 5168 ``behind``: insert behind the specified filter (default). 5169 5170 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5171 filter-mirror on netdev netdevid,mirror net packet to 5172 chardevchardevid, if it has the vnet\_hdr\_support flag, 5173 filter-mirror will mirror packet with vnet\_hdr\_len. 5174 5175 ``-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]`` 5176 filter-redirector on netdev netdevid,redirect filter's net 5177 packet to chardev chardevid,and redirect indev's packet to 5178 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5179 will redirect packet with vnet\_hdr\_len. Create a 5180 filter-redirector we need to differ outdev id from indev id, id 5181 can not be the same. we can just use indev or outdev, but at 5182 least one of indev or outdev need to be specified. 5183 5184 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5185 Filter-rewriter is a part of COLO project.It will rewrite tcp 5186 packet to secondary from primary to keep secondary tcp 5187 connection,and rewrite tcp packet to primary from secondary make 5188 tcp packet can be handled by client.if it has the 5189 vnet\_hdr\_support flag, we can parse packet with vnet header. 5190 5191 usage: colo secondary: -object 5192 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5193 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5194 filter-rewriter,id=rew0,netdev=hn0,queue=all 5195 5196 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5197 Dump the network traffic on netdev dev to the file specified by 5198 filename. At most len bytes (64k by default) per packet are 5199 stored. The file format is libpcap, so it can be analyzed with 5200 tools such as tcpdump or Wireshark. 5201 5202 ``-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}]`` 5203 Colo-compare gets packet from primary\_in chardevid and 5204 secondary\_in, then compare whether the payload of primary packet 5205 and secondary packet are the same. If same, it will output 5206 primary packet to out\_dev, else it will notify COLO-framework to do 5207 checkpoint and send primary packet to out\_dev. In order to 5208 improve efficiency, we need to put the task of comparison in 5209 another iothread. If it has the vnet\_hdr\_support flag, 5210 colo compare will send/recv packet with vnet\_hdr\_len. 5211 The compare\_timeout=@var{ms} determines the maximum time of the 5212 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5213 is to set the period of scanning expired primary node network packets. 5214 The max\_queue\_size=@var{size} is to set the max compare queue 5215 size depend on user environment. 5216 If user want to use Xen COLO, need to add the notify\_dev to 5217 notify Xen colo-frame to do checkpoint. 5218 5219 COLO-compare must be used with the help of filter-mirror, 5220 filter-redirector and filter-rewriter. 5221 5222 :: 5223 5224 KVM COLO 5225 5226 primary: 5227 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5228 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5229 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5230 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5231 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5232 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5233 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5234 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5235 -object iothread,id=iothread1 5236 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5237 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5238 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5239 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5240 5241 secondary: 5242 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5243 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5244 -chardev socket,id=red0,host=3.3.3.3,port=9003 5245 -chardev socket,id=red1,host=3.3.3.3,port=9004 5246 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5247 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5248 5249 5250 Xen COLO 5251 5252 primary: 5253 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5254 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5255 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5256 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5257 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5258 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5259 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5260 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5261 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5262 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5263 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5264 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5265 -object iothread,id=iothread1 5266 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5267 5268 secondary: 5269 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5270 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5271 -chardev socket,id=red0,host=3.3.3.3,port=9003 5272 -chardev socket,id=red1,host=3.3.3.3,port=9004 5273 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5274 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5275 5276 If you want to know the detail of above command line, you can 5277 read the colo-compare git log. 5278 5279 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5280 Creates a cryptodev backend which executes crypto operations from 5281 the QEMU cipher APIs. The id parameter is a unique ID that will 5282 be used to reference this cryptodev backend from the 5283 ``virtio-crypto`` device. The queues parameter is optional, 5284 which specify the queue number of cryptodev backend, the default 5285 of queues is 1. 5286 5287 .. parsed-literal:: 5288 5289 # |qemu_system| \\ 5290 [...] \\ 5291 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5292 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5293 [...] 5294 5295 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5296 Creates a vhost-user cryptodev backend, backed by a chardev 5297 chardevid. The id parameter is a unique ID that will be used to 5298 reference this cryptodev backend from the ``virtio-crypto`` 5299 device. The chardev should be a unix domain socket backed one. 5300 The vhost-user uses a specifically defined protocol to pass 5301 vhost ioctl replacement messages to an application on the other 5302 end of the socket. The queues parameter is optional, which 5303 specify the queue number of cryptodev backend for multiqueue 5304 vhost-user, the default of queues is 1. 5305 5306 .. parsed-literal:: 5307 5308 # |qemu_system| \\ 5309 [...] \\ 5310 -chardev socket,id=chardev0,path=/path/to/socket \\ 5311 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5312 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5313 [...] 5314 5315 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5316 \ 5317 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5318 Defines a secret to store a password, encryption key, or some 5319 other sensitive data. The sensitive data can either be passed 5320 directly via the data parameter, or indirectly via the file 5321 parameter. Using the data parameter is insecure unless the 5322 sensitive data is encrypted. 5323 5324 The sensitive data can be provided in raw format (the default), 5325 or base64. When encoded as JSON, the raw format only supports 5326 valid UTF-8 characters, so base64 is recommended for sending 5327 binary data. QEMU will convert from which ever format is 5328 provided to the format it needs internally. eg, an RBD password 5329 can be provided in raw format, even though it will be base64 5330 encoded when passed onto the RBD sever. 5331 5332 For added protection, it is possible to encrypt the data 5333 associated with a secret using the AES-256-CBC cipher. Use of 5334 encryption is indicated by providing the keyid and iv 5335 parameters. The keyid parameter provides the ID of a previously 5336 defined secret that contains the AES-256 decryption key. This 5337 key should be 32-bytes long and be base64 encoded. The iv 5338 parameter provides the random initialization vector used for 5339 encryption of this particular secret and should be a base64 5340 encrypted string of the 16-byte IV. 5341 5342 The simplest (insecure) usage is to provide the secret inline 5343 5344 .. parsed-literal:: 5345 5346 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5347 5348 The simplest secure usage is to provide the secret via a file 5349 5350 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5351 secret,id=sec0,file=mypasswd.txt,format=raw 5352 5353 For greater security, AES-256-CBC should be used. To illustrate 5354 usage, consider the openssl command line tool which can encrypt 5355 the data. Note that when encrypting, the plaintext must be 5356 padded to the cipher block size (32 bytes) using the standard 5357 PKCS#5/6 compatible padding algorithm. 5358 5359 First a master key needs to be created in base64 encoding: 5360 5361 :: 5362 5363 # openssl rand -base64 32 > key.b64 5364 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5365 5366 Each secret to be encrypted needs to have a random 5367 initialization vector generated. These do not need to be kept 5368 secret 5369 5370 :: 5371 5372 # openssl rand -base64 16 > iv.b64 5373 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5374 5375 The secret to be defined can now be encrypted, in this case 5376 we're telling openssl to base64 encode the result, but it could 5377 be left as raw bytes if desired. 5378 5379 :: 5380 5381 # SECRET=$(printf "letmein" | 5382 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5383 5384 When launching QEMU, create a master secret pointing to 5385 ``key.b64`` and specify that to be used to decrypt the user 5386 password. Pass the contents of ``iv.b64`` to the second secret 5387 5388 .. parsed-literal:: 5389 5390 # |qemu_system| \\ 5391 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5392 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5393 data=$SECRET,iv=$(<iv.b64) 5394 5395 ``-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]`` 5396 Create a Secure Encrypted Virtualization (SEV) guest object, 5397 which can be used to provide the guest memory encryption support 5398 on AMD processors. 5399 5400 When memory encryption is enabled, one of the physical address 5401 bit (aka the C-bit) is utilized to mark if a memory page is 5402 protected. The ``cbitpos`` is used to provide the C-bit 5403 position. The C-bit position is Host family dependent hence user 5404 must provide this value. On EPYC, the value should be 47. 5405 5406 When memory encryption is enabled, we loose certain bits in 5407 physical address space. The ``reduced-phys-bits`` is used to 5408 provide the number of bits we loose in physical address space. 5409 Similar to C-bit, the value is Host family dependent. On EPYC, 5410 the value should be 5. 5411 5412 The ``sev-device`` provides the device file to use for 5413 communicating with the SEV firmware running inside AMD Secure 5414 Processor. The default device is '/dev/sev'. If hardware 5415 supports memory encryption then /dev/sev devices are created by 5416 CCP driver. 5417 5418 The ``policy`` provides the guest policy to be enforced by the 5419 SEV firmware and restrict what configuration and operational 5420 commands can be performed on this guest by the hypervisor. The 5421 policy should be provided by the guest owner and is bound to the 5422 guest and cannot be changed throughout the lifetime of the 5423 guest. The default is 0. 5424 5425 If guest ``policy`` allows sharing the key with another SEV 5426 guest then ``handle`` can be use to provide handle of the guest 5427 from which to share the key. 5428 5429 The ``dh-cert-file`` and ``session-file`` provides the guest 5430 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5431 and session parameters are used for establishing a cryptographic 5432 session with the guest owner to negotiate keys used for 5433 attestation. The file must be encoded in base64. 5434 5435 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5436 cmdline to a designated guest firmware page for measured Linux 5437 boot with -kernel. The default is off. (Since 6.2) 5438 5439 e.g to launch a SEV guest 5440 5441 .. parsed-literal:: 5442 5443 # |qemu_system_x86| \\ 5444 ...... \\ 5445 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5446 -machine ...,memory-encryption=sev0 \\ 5447 ..... 5448 5449 ``-object authz-simple,id=id,identity=string`` 5450 Create an authorization object that will control access to 5451 network services. 5452 5453 The ``identity`` parameter is identifies the user and its format 5454 depends on the network service that authorization object is 5455 associated with. For authorizing based on TLS x509 certificates, 5456 the identity must be the x509 distinguished name. Note that care 5457 must be taken to escape any commas in the distinguished name. 5458 5459 An example authorization object to validate a x509 distinguished 5460 name would look like: 5461 5462 .. parsed-literal:: 5463 5464 # |qemu_system| \\ 5465 ... \\ 5466 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5467 ... 5468 5469 Note the use of quotes due to the x509 distinguished name 5470 containing whitespace, and escaping of ','. 5471 5472 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5473 Create an authorization object that will control access to 5474 network services. 5475 5476 The ``filename`` parameter is the fully qualified path to a file 5477 containing the access control list rules in JSON format. 5478 5479 An example set of rules that match against SASL usernames might 5480 look like: 5481 5482 :: 5483 5484 { 5485 "rules": [ 5486 { "match": "fred", "policy": "allow", "format": "exact" }, 5487 { "match": "bob", "policy": "allow", "format": "exact" }, 5488 { "match": "danb", "policy": "deny", "format": "glob" }, 5489 { "match": "dan*", "policy": "allow", "format": "exact" }, 5490 ], 5491 "policy": "deny" 5492 } 5493 5494 When checking access the object will iterate over all the rules 5495 and the first rule to match will have its ``policy`` value 5496 returned as the result. If no rules match, then the default 5497 ``policy`` value is returned. 5498 5499 The rules can either be an exact string match, or they can use 5500 the simple UNIX glob pattern matching to allow wildcards to be 5501 used. 5502 5503 If ``refresh`` is set to true the file will be monitored and 5504 automatically reloaded whenever its content changes. 5505 5506 As with the ``authz-simple`` object, the format of the identity 5507 strings being matched depends on the network service, but is 5508 usually a TLS x509 distinguished name, or a SASL username. 5509 5510 An example authorization object to validate a SASL username 5511 would look like: 5512 5513 .. parsed-literal:: 5514 5515 # |qemu_system| \\ 5516 ... \\ 5517 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5518 ... 5519 5520 ``-object authz-pam,id=id,service=string`` 5521 Create an authorization object that will control access to 5522 network services. 5523 5524 The ``service`` parameter provides the name of a PAM service to 5525 use for authorization. It requires that a file 5526 ``/etc/pam.d/service`` exist to provide the configuration for 5527 the ``account`` subsystem. 5528 5529 An example authorization object to validate a TLS x509 5530 distinguished name would look like: 5531 5532 .. parsed-literal:: 5533 5534 # |qemu_system| \\ 5535 ... \\ 5536 -object authz-pam,id=auth0,service=qemu-vnc \\ 5537 ... 5538 5539 There would then be a corresponding config file for PAM at 5540 ``/etc/pam.d/qemu-vnc`` that contains: 5541 5542 :: 5543 5544 account requisite pam_listfile.so item=user sense=allow \ 5545 file=/etc/qemu/vnc.allow 5546 5547 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5548 of x509 distinguished names that are permitted access 5549 5550 :: 5551 5552 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5553 5554 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5555 Creates a dedicated event loop thread that devices can be 5556 assigned to. This is known as an IOThread. By default device 5557 emulation happens in vCPU threads or the main event loop thread. 5558 This can become a scalability bottleneck. IOThreads allow device 5559 emulation and I/O to run on other host CPUs. 5560 5561 The ``id`` parameter is a unique ID that will be used to 5562 reference this IOThread from ``-device ...,iothread=id``. 5563 Multiple devices can be assigned to an IOThread. Note that not 5564 all devices support an ``iothread`` parameter. 5565 5566 The ``query-iothreads`` QMP command lists IOThreads and reports 5567 their thread IDs so that the user can configure host CPU 5568 pinning/affinity. 5569 5570 IOThreads use an adaptive polling algorithm to reduce event loop 5571 latency. Instead of entering a blocking system call to monitor 5572 file descriptors and then pay the cost of being woken up when an 5573 event occurs, the polling algorithm spins waiting for events for 5574 a short time. The algorithm's default parameters are suitable 5575 for many cases but can be adjusted based on knowledge of the 5576 workload and/or host device latency. 5577 5578 The ``poll-max-ns`` parameter is the maximum number of 5579 nanoseconds to busy wait for events. Polling can be disabled by 5580 setting this value to 0. 5581 5582 The ``poll-grow`` parameter is the multiplier used to increase 5583 the polling time when the algorithm detects it is missing events 5584 due to not polling long enough. 5585 5586 The ``poll-shrink`` parameter is the divisor used to decrease 5587 the polling time when the algorithm detects it is spending too 5588 long polling without encountering events. 5589 5590 The ``aio-max-batch`` parameter is the maximum number of requests 5591 in a batch for the AIO engine, 0 means that the engine will use 5592 its default. 5593 5594 The IOThread parameters can be modified at run-time using the 5595 ``qom-set`` command (where ``iothread1`` is the IOThread's 5596 ``id``): 5597 5598 :: 5599 5600 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5601ERST 5602 5603 5604HXCOMM This is the last statement. Insert new options before this line! 5605 5606#undef DEF 5607#undef DEFHEADING 5608#undef ARCHHEADING 5609
