1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST version and 3HXCOMM discarded from C version. 4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 5HXCOMM construct option structures, enums and help message for specified 6HXCOMM architectures. 7HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hax, hvf, nvmm, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 40 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 41 QEMU_ARCH_ALL) 42SRST 43``-machine [type=]name[,prop=value[,...]]`` 44 Select the emulated machine by name. Use ``-machine help`` to list 45 available machines. 46 47 For architectures which aim to support live migration compatibility 48 across releases, each release will introduce a new versioned machine 49 type. For example, the 2.8.0 release introduced machine types 50 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 51 52 To allow live migration of guests from QEMU version 2.8.0, to QEMU 53 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 54 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 55 skip multiple intermediate releases when upgrading, new releases of 56 QEMU will support machine types from many previous versions. 57 58 Supported machine properties are: 59 60 ``accel=accels1[:accels2[:...]]`` 61 This is used to enable an accelerator. Depending on the target 62 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 63 By default, tcg is used. If there is more than one accelerator 64 specified, the next one is used if the previous one fails to 65 initialize. 66 67 ``vmport=on|off|auto`` 68 Enables emulation of VMWare IO port, for vmmouse etc. auto says 69 to select the value based on accel. For accel=xen the default is 70 off otherwise the default is on. 71 72 ``dump-guest-core=on|off`` 73 Include guest memory in a core dump. The default is on. 74 75 ``mem-merge=on|off`` 76 Enables or disables memory merge support. This feature, when 77 supported by the host, de-duplicates identical memory pages 78 among VMs instances (enabled by default). 79 80 ``aes-key-wrap=on|off`` 81 Enables or disables AES key wrapping support on s390-ccw hosts. 82 This feature controls whether AES wrapping keys will be created 83 to allow execution of AES cryptographic functions. The default 84 is on. 85 86 ``dea-key-wrap=on|off`` 87 Enables or disables DEA key wrapping support on s390-ccw hosts. 88 This feature controls whether DEA wrapping keys will be created 89 to allow execution of DEA cryptographic functions. The default 90 is on. 91 92 ``nvdimm=on|off`` 93 Enables or disables NVDIMM support. The default is off. 94 95 ``memory-encryption=`` 96 Memory encryption object to use. The default is none. 97 98 ``hmat=on|off`` 99 Enables or disables ACPI Heterogeneous Memory Attribute Table 100 (HMAT) support. The default is off. 101 102 ``memory-backend='id'`` 103 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 104 Allows to use a memory backend as main RAM. 105 106 For example: 107 :: 108 109 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 110 -machine memory-backend=pc.ram 111 -m 512M 112 113 Migration compatibility note: 114 115 * as backend id one shall use value of 'default-ram-id', advertised by 116 machine type (available via ``query-machines`` QMP command), if migration 117 to/from old QEMU (<5.0) is expected. 118 * for machine types 4.0 and older, user shall 119 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 120 if migration to/from old QEMU (<5.0) is expected. 121 122 For example: 123 :: 124 125 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 126 -machine memory-backend=pc.ram 127 -m 512M 128 129 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 130 Define a CXL Fixed Memory Window (CFMW). 131 132 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 133 134 They are regions of Host Physical Addresses (HPA) on a system which 135 may be interleaved across one or more CXL host bridges. The system 136 software will assign particular devices into these windows and 137 configure the downstream Host-managed Device Memory (HDM) decoders 138 in root ports, switch ports and devices appropriately to meet the 139 interleave requirements before enabling the memory devices. 140 141 ``targets.X=target`` provides the mapping to CXL host bridges 142 which may be identified by the id provided in the -device entry. 143 Multiple entries are needed to specify all the targets when 144 the fixed memory window represents interleaved memory. X is the 145 target index from 0. 146 147 ``size=size`` sets the size of the CFMW. This must be a multiple of 148 256MiB. The region will be aligned to 256MiB but the location is 149 platform and configuration dependent. 150 151 ``interleave-granularity=granularity`` sets the granularity of 152 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 153 4096KiB, 8192KiB and 16384KiB granularities supported. 154 155 Example: 156 157 :: 158 159 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k 160ERST 161 162DEF("M", HAS_ARG, QEMU_OPTION_M, 163 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 164 QEMU_ARCH_ALL) 165 166SRST 167``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 168 Define an SGX EPC section. 169ERST 170 171DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 172 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 173SRST 174``-cpu model`` 175 Select CPU model (``-cpu help`` for list and additional feature 176 selection) 177ERST 178 179DEF("accel", HAS_ARG, QEMU_OPTION_accel, 180 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 181 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 182 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 183 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 184 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 185 " split-wx=on|off (enable TCG split w^x mapping)\n" 186 " tb-size=n (TCG translation block cache size)\n" 187 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 188 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 189 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 190SRST 191``-accel name[,prop=value[,...]]`` 192 This is used to enable an accelerator. Depending on the target 193 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 194 default, tcg is used. If there is more than one accelerator 195 specified, the next one is used if the previous one fails to 196 initialize. 197 198 ``igd-passthru=on|off`` 199 When Xen is in use, this option controls whether Intel 200 integrated graphics devices can be passed through to the guest 201 (default=off) 202 203 ``kernel-irqchip=on|off|split`` 204 Controls KVM in-kernel irqchip support. The default is full 205 acceleration of the interrupt controllers. On x86, split irqchip 206 reduces the kernel attack surface, at a performance cost for 207 non-MSI interrupts. Disabling the in-kernel irqchip completely 208 is not recommended except for debugging purposes. 209 210 ``kvm-shadow-mem=size`` 211 Defines the size of the KVM shadow MMU. 212 213 ``split-wx=on|off`` 214 Controls the use of split w^x mapping for the TCG code generation 215 buffer. Some operating systems require this to be enabled, and in 216 such a case this will default on. On other operating systems, this 217 will default off, but one may enable this for testing or debugging. 218 219 ``tb-size=n`` 220 Controls the size (in MiB) of the TCG translation block cache. 221 222 ``thread=single|multi`` 223 Controls number of TCG threads. When the TCG is multi-threaded 224 there will be one thread per vCPU therefore taking advantage of 225 additional host cores. The default is to enable multi-threading 226 where both the back-end and front-ends support it and no 227 incompatible TCG features have been enabled (e.g. 228 icount/replay). 229 230 ``dirty-ring-size=n`` 231 When the KVM accelerator is used, it controls the size of the per-vCPU 232 dirty page ring buffer (number of entries for each vCPU). It should 233 be a value that is power of two, and it should be 1024 or bigger (but 234 still less than the maximum value that the kernel supports). 4096 235 could be a good initial value if you have no idea which is the best. 236 Set this value to 0 to disable the feature. By default, this feature 237 is disabled (dirty-ring-size=0). When enabled, KVM will instead 238 record dirty pages in a bitmap. 239 240 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 241 Enables or disables notify VM exit support on x86 host and specify 242 the corresponding notify window to trigger the VM exit if enabled. 243 ``run`` option enables the feature. It does nothing and continue 244 if the exit happens. ``internal-error`` option enables the feature. 245 It raises a internal error. ``disable`` option doesn't enable the feature. 246 This feature can mitigate the CPU stuck issue due to event windows don't 247 open up for a specified of time (i.e. notify-window). 248 Default: notify-vmexit=run,notify-window=0. 249 250ERST 251 252DEF("smp", HAS_ARG, QEMU_OPTION_smp, 253 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 254 " set the number of initial CPUs to 'n' [default=1]\n" 255 " maxcpus= maximum number of total CPUs, including\n" 256 " offline CPUs for hotplug, etc\n" 257 " sockets= number of sockets on the machine board\n" 258 " dies= number of dies in one socket\n" 259 " clusters= number of clusters in one die\n" 260 " cores= number of cores in one cluster\n" 261 " threads= number of threads in one core\n" 262 "Note: Different machines may have different subsets of the CPU topology\n" 263 " parameters supported, so the actual meaning of the supported parameters\n" 264 " will vary accordingly. For example, for a machine type that supports a\n" 265 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 266 " sequentially mean as below:\n" 267 " sockets means the number of sockets on the machine board\n" 268 " cores means the number of cores in one socket\n" 269 " threads means the number of threads in one core\n" 270 " For a particular machine type board, an expected CPU topology hierarchy\n" 271 " can be defined through the supported sub-option. Unsupported parameters\n" 272 " can also be provided in addition to the sub-option, but their values\n" 273 " must be set as 1 in the purpose of correct parsing.\n", 274 QEMU_ARCH_ALL) 275SRST 276``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 277 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 278 the machine type board. On boards supporting CPU hotplug, the optional 279 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 280 added at runtime. When both parameters are omitted, the maximum number 281 of CPUs will be calculated from the provided topology members and the 282 initial CPU count will match the maximum number. When only one of them 283 is given then the omitted one will be set to its counterpart's value. 284 Both parameters may be specified, but the maximum number of CPUs must 285 be equal to or greater than the initial CPU count. Product of the 286 CPU topology hierarchy must be equal to the maximum number of CPUs. 287 Both parameters are subject to an upper limit that is determined by 288 the specific machine type chosen. 289 290 To control reporting of CPU topology information, values of the topology 291 parameters can be specified. Machines may only support a subset of the 292 parameters and different machines may have different subsets supported 293 which vary depending on capacity of the corresponding CPU targets. So 294 for a particular machine type board, an expected topology hierarchy can 295 be defined through the supported sub-option. Unsupported parameters can 296 also be provided in addition to the sub-option, but their values must be 297 set as 1 in the purpose of correct parsing. 298 299 Either the initial CPU count, or at least one of the topology parameters 300 must be specified. The specified parameters must be greater than zero, 301 explicit configuration like "cpus=0" is not allowed. Values for any 302 omitted parameters will be computed from those which are given. 303 304 For example, the following sub-option defines a CPU topology hierarchy 305 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 306 core) for a machine that only supports sockets/cores/threads. 307 Some members of the option can be omitted but their values will be 308 automatically computed: 309 310 :: 311 312 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 313 314 The following sub-option defines a CPU topology hierarchy (2 sockets 315 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 316 per core) for PC machines which support sockets/dies/cores/threads. 317 Some members of the option can be omitted but their values will be 318 automatically computed: 319 320 :: 321 322 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 323 324 The following sub-option defines a CPU topology hierarchy (2 sockets 325 totally on the machine, 2 clusters per socket, 2 cores per cluster, 326 2 threads per core) for ARM virt machines which support sockets/clusters 327 /cores/threads. Some members of the option can be omitted but their values 328 will be automatically computed: 329 330 :: 331 332 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 333 334 Historically preference was given to the coarsest topology parameters 335 when computing missing values (ie sockets preferred over cores, which 336 were preferred over threads), however, this behaviour is considered 337 liable to change. Prior to 6.2 the preference was sockets over cores 338 over threads. Since 6.2 the preference is cores over sockets over threads. 339 340 For example, the following option defines a machine board with 2 sockets 341 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 342 343 :: 344 345 -smp 2 346 347 Note: The cluster topology will only be generated in ACPI and exposed 348 to guest if it's explicitly specified in -smp. 349ERST 350 351DEF("numa", HAS_ARG, QEMU_OPTION_numa, 352 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 353 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 354 "-numa dist,src=source,dst=destination,val=distance\n" 355 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 356 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n" 357 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 358 QEMU_ARCH_ALL) 359SRST 360``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 361 \ 362``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 363 \ 364``-numa dist,src=source,dst=destination,val=distance`` 365 \ 366``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 367 \ 368``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 369 \ 370``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 371 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 372 distance from a source node to a destination node. Set the ACPI 373 Heterogeneous Memory Attributes for the given nodes. 374 375 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 376 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 377 contiguous range of CPU indexes (or a single VCPU if lastcpu is 378 omitted). A non-contiguous set of VCPUs can be represented by 379 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 380 omitted on all nodes, VCPUs are automatically split between them. 381 382 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 383 NUMA node: 384 385 :: 386 387 -numa node,cpus=0-2,cpus=5 388 389 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 390 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 391 assign CPU objects to a node using topology layout properties of 392 CPU. The set of properties is machine specific, and depends on used 393 machine type/'\ ``smp``\ ' options. It could be queried with 394 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 395 property specifies node to which CPU object will be assigned, it's 396 required for node to be declared with '\ ``node``\ ' option before 397 it's used with '\ ``cpu``\ ' option. 398 399 For example: 400 401 :: 402 403 -M pc \ 404 -smp 1,sockets=2,maxcpus=2 \ 405 -numa node,nodeid=0 -numa node,nodeid=1 \ 406 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 407 408 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 409 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 410 a given memory backend device to a node. If '\ ``mem``\ ' and 411 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 412 413 414 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 415 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 416 use it. 417 418 '\ ``initiator``\ ' is an additional option that points to an 419 initiator NUMA node that has best performance (the lowest latency or 420 largest bandwidth) to this NUMA node. Note that this option can be 421 set only when the machine property 'hmat' is set to 'on'. 422 423 Following example creates a machine with 2 NUMA nodes, node 0 has 424 CPU. node 1 has only memory, and its initiator is node 0. Note that 425 because node 0 has CPU, by default the initiator of node 0 is itself 426 and must be itself. 427 428 :: 429 430 -machine hmat=on \ 431 -m 2G,slots=2,maxmem=4G \ 432 -object memory-backend-ram,size=1G,id=m0 \ 433 -object memory-backend-ram,size=1G,id=m1 \ 434 -numa node,nodeid=0,memdev=m0 \ 435 -numa node,nodeid=1,memdev=m1,initiator=0 \ 436 -smp 2,sockets=2,maxcpus=2 \ 437 -numa cpu,node-id=0,socket-id=0 \ 438 -numa cpu,node-id=0,socket-id=1 439 440 source and destination are NUMA node IDs. distance is the NUMA 441 distance from source to destination. The distance from a node to 442 itself is always 10. If any pair of nodes is given a distance, then 443 all pairs must be given distances. Although, when distances are only 444 given in one direction for each pair of nodes, then the distances in 445 the opposite directions are assumed to be the same. If, however, an 446 asymmetrical pair of distances is given for even one node pair, then 447 all node pairs must be provided distance values for both directions, 448 even when they are symmetrical. When a node is unreachable from 449 another node, set the pair's distance to 255. 450 451 Note that the -``numa`` option doesn't allocate any of the specified 452 resources, it just assigns existing resources to NUMA nodes. This 453 means that one still has to use the ``-m``, ``-smp`` options to 454 allocate RAM and VCPUs respectively. 455 456 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 457 Information between initiator and target NUMA nodes in ACPI 458 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 459 create memory requests, usually it has one or more processors. 460 Target NUMA node contains addressable memory. 461 462 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 463 the memory hierarchy of the target NUMA node: if hierarchy is 464 'memory', the structure represents the memory performance; if 465 hierarchy is 'first-level\|second-level\|third-level', this 466 structure represents aggregated performance of memory side caches 467 for each domain. type of 'data-type' is type of data represented by 468 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 469 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 470 the target memory; if 'hierarchy' is 471 'first-level\|second-level\|third-level', 'data-type' is 472 'access\|read\|write' hit latency or 'access\|read\|write' hit 473 bandwidth of the target memory side cache. 474 475 lat is latency value in nanoseconds. bw is bandwidth value, the 476 possible value and units are NUM[M\|G\|T], mean that the bandwidth 477 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 478 used suffix). Note that if latency or bandwidth value is 0, means 479 the corresponding latency or bandwidth information is not provided. 480 481 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 482 belongs. size is the size of memory side cache in bytes. level is 483 the cache level described in this structure, note that the cache 484 level 0 should not be used with '\ ``hmat-cache``\ ' option. 485 associativity is the cache associativity, the possible value is 486 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 487 is the write policy. line is the cache Line size in bytes. 488 489 For example, the following options describe 2 NUMA nodes. Node 0 has 490 2 cpus and a ram, node 1 has only a ram. The processors in node 0 491 access memory in node 0 with access-latency 5 nanoseconds, 492 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 493 memory in NUMA node 1 with access-latency 10 nanoseconds, 494 access-bandwidth is 100 MB/s. And for memory side cache information, 495 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 496 policy is write-back, the cache Line size is 8 bytes: 497 498 :: 499 500 -machine hmat=on \ 501 -m 2G \ 502 -object memory-backend-ram,size=1G,id=m0 \ 503 -object memory-backend-ram,size=1G,id=m1 \ 504 -smp 2,sockets=2,maxcpus=2 \ 505 -numa node,nodeid=0,memdev=m0 \ 506 -numa node,nodeid=1,memdev=m1,initiator=0 \ 507 -numa cpu,node-id=0,socket-id=0 \ 508 -numa cpu,node-id=0,socket-id=1 \ 509 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 510 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 511 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 512 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 513 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 514 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 515ERST 516 517DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 518 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 519 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 520SRST 521``-add-fd fd=fd,set=set[,opaque=opaque]`` 522 Add a file descriptor to an fd set. Valid options are: 523 524 ``fd=fd`` 525 This option defines the file descriptor of which a duplicate is 526 added to fd set. The file descriptor cannot be stdin, stdout, or 527 stderr. 528 529 ``set=set`` 530 This option defines the ID of the fd set to add the file 531 descriptor to. 532 533 ``opaque=opaque`` 534 This option defines a free-form string that can be used to 535 describe fd. 536 537 You can open an image using pre-opened file descriptors from an fd 538 set: 539 540 .. parsed-literal:: 541 542 |qemu_system| \\ 543 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 544 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 545 -drive file=/dev/fdset/2,index=0,media=disk 546ERST 547 548DEF("set", HAS_ARG, QEMU_OPTION_set, 549 "-set group.id.arg=value\n" 550 " set <arg> parameter for item <id> of type <group>\n" 551 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 552SRST 553``-set group.id.arg=value`` 554 Set parameter arg for item id of type group 555ERST 556 557DEF("global", HAS_ARG, QEMU_OPTION_global, 558 "-global driver.property=value\n" 559 "-global driver=driver,property=property,value=value\n" 560 " set a global default for a driver property\n", 561 QEMU_ARCH_ALL) 562SRST 563``-global driver.prop=value`` 564 \ 565``-global driver=driver,property=property,value=value`` 566 Set default value of driver's property prop to value, e.g.: 567 568 .. parsed-literal:: 569 570 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 571 572 In particular, you can use this to set driver properties for devices 573 which are created automatically by the machine model. To create a 574 device which is not created automatically and set properties on it, 575 use -``device``. 576 577 -global driver.prop=value is shorthand for -global 578 driver=driver,property=prop,value=value. The longhand syntax works 579 even when driver contains a dot. 580ERST 581 582DEF("boot", HAS_ARG, QEMU_OPTION_boot, 583 "-boot [order=drives][,once=drives][,menu=on|off]\n" 584 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 585 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 586 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 587 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 588 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 589 QEMU_ARCH_ALL) 590SRST 591``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 592 Specify boot order drives as a string of drive letters. Valid drive 593 letters depend on the target architecture. The x86 PC uses: a, b 594 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 595 (Etherboot from network adapter 1-4), hard disk boot is the default. 596 To apply a particular boot order only on the first startup, specify 597 it via ``once``. Note that the ``order`` or ``once`` parameter 598 should not be used together with the ``bootindex`` property of 599 devices, since the firmware implementations normally do not support 600 both at the same time. 601 602 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 603 as firmware/BIOS supports them. The default is non-interactive boot. 604 605 A splash picture could be passed to bios, enabling user to show it 606 as logo, when option splash=sp\_name is given and menu=on, If 607 firmware/BIOS supports them. Currently Seabios for X86 system 608 support it. limitation: The splash file could be a jpeg file or a 609 BMP file in 24 BPP format(true color). The resolution should be 610 supported by the SVGA mode, so the recommended is 320x240, 640x480, 611 800x640. 612 613 A timeout could be passed to bios, guest will pause for rb\_timeout 614 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 615 not reboot, qemu passes '-1' to bios by default. Currently Seabios 616 for X86 system support it. 617 618 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 619 it. This only effects when boot priority is changed by bootindex 620 options. The default is non-strict boot. 621 622 .. parsed-literal:: 623 624 # try to boot from network first, then from hard disk 625 |qemu_system_x86| -boot order=nc 626 # boot from CD-ROM first, switch back to default order after reboot 627 |qemu_system_x86| -boot once=d 628 # boot with a splash picture for 5 seconds. 629 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 630 631 Note: The legacy format '-boot drives' is still supported but its 632 use is discouraged as it may be removed from future versions. 633ERST 634 635DEF("m", HAS_ARG, QEMU_OPTION_m, 636 "-m [size=]megs[,slots=n,maxmem=size]\n" 637 " configure guest RAM\n" 638 " size: initial amount of guest memory\n" 639 " slots: number of hotplug slots (default: none)\n" 640 " maxmem: maximum amount of guest memory (default: none)\n" 641 "NOTE: Some architectures might enforce a specific granularity\n", 642 QEMU_ARCH_ALL) 643SRST 644``-m [size=]megs[,slots=n,maxmem=size]`` 645 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 646 Optionally, a suffix of "M" or "G" can be used to signify a value in 647 megabytes or gigabytes respectively. Optional pair slots, maxmem 648 could be used to set amount of hotpluggable memory slots and maximum 649 amount of memory. Note that maxmem must be aligned to the page size. 650 651 For example, the following command-line sets the guest startup RAM 652 size to 1GB, creates 3 slots to hotplug additional memory and sets 653 the maximum memory the guest can reach to 4GB: 654 655 .. parsed-literal:: 656 657 |qemu_system| -m 1G,slots=3,maxmem=4G 658 659 If slots and maxmem are not specified, memory hotplug won't be 660 enabled and the guest startup RAM will never increase. 661ERST 662 663DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 664 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 665SRST 666``-mem-path path`` 667 Allocate guest RAM from a temporarily created file in path. 668ERST 669 670DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 671 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 672 QEMU_ARCH_ALL) 673SRST 674``-mem-prealloc`` 675 Preallocate memory when using -mem-path. 676ERST 677 678DEF("k", HAS_ARG, QEMU_OPTION_k, 679 "-k language use keyboard layout (for example 'fr' for French)\n", 680 QEMU_ARCH_ALL) 681SRST 682``-k language`` 683 Use keyboard layout language (for example ``fr`` for French). This 684 option is only needed where it is not easy to get raw PC keycodes 685 (e.g. on Macs, with some X11 servers or with a VNC or curses 686 display). You don't normally need to use it on PC/Linux or 687 PC/Windows hosts. 688 689 The available layouts are: 690 691 :: 692 693 ar de-ch es fo fr-ca hu ja mk no pt-br sv 694 da en-gb et fr fr-ch is lt nl pl ru th 695 de en-us fi fr-be hr it lv nl-be pt sl tr 696 697 The default is ``en-us``. 698ERST 699 700 701HXCOMM Deprecated by -audiodev 702DEF("audio-help", 0, QEMU_OPTION_audio_help, 703 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 704 QEMU_ARCH_ALL) 705SRST 706``-audio-help`` 707 Will show the -audiodev equivalent of the currently specified 708 (deprecated) environment variables. 709ERST 710 711DEF("audio", HAS_ARG, QEMU_OPTION_audio, 712 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 713 " specifies the audio backend and device to use;\n" 714 " apart from 'model', options are the same as for -audiodev.\n" 715 " use '-audio model=help' to show possible devices.\n", 716 QEMU_ARCH_ALL) 717SRST 718``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 719 This option is a shortcut for configuring both the guest audio 720 hardware and the host audio backend in one go. 721 The driver option is the same as with the corresponding ``-audiodev`` option below. 722 The guest hardware model can be set with ``model=modelname``. 723 724 Use ``driver=help`` to list the available drivers, 725 and ``model=help`` to list the available device types. 726 727 The following two example do exactly the same, to show how ``-audio`` 728 can be used to shorten the command line length: 729 730 .. parsed-literal:: 731 732 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 733 |qemu_system| -audio pa,model=sb16 734ERST 735 736DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 737 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 738 " specifies the audio backend to use\n" 739 " Use ``-audiodev help`` to list the available drivers\n" 740 " id= identifier of the backend\n" 741 " timer-period= timer period in microseconds\n" 742 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 743 " in|out.fixed-settings= use fixed settings for host audio\n" 744 " in|out.frequency= frequency to use with fixed settings\n" 745 " in|out.channels= number of channels to use with fixed settings\n" 746 " in|out.format= sample format to use with fixed settings\n" 747 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 748 " in|out.voices= number of voices to use\n" 749 " in|out.buffer-length= length of buffer in microseconds\n" 750 "-audiodev none,id=id,[,prop[=value][,...]]\n" 751 " dummy driver that discards all output\n" 752#ifdef CONFIG_AUDIO_ALSA 753 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 754 " in|out.dev= name of the audio device to use\n" 755 " in|out.period-length= length of period in microseconds\n" 756 " in|out.try-poll= attempt to use poll mode\n" 757 " threshold= threshold (in microseconds) when playback starts\n" 758#endif 759#ifdef CONFIG_AUDIO_COREAUDIO 760 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 761 " in|out.buffer-count= number of buffers\n" 762#endif 763#ifdef CONFIG_AUDIO_DSOUND 764 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 765 " latency= add extra latency to playback in microseconds\n" 766#endif 767#ifdef CONFIG_AUDIO_OSS 768 "-audiodev oss,id=id[,prop[=value][,...]]\n" 769 " in|out.dev= path of the audio device to use\n" 770 " in|out.buffer-count= number of buffers\n" 771 " in|out.try-poll= attempt to use poll mode\n" 772 " try-mmap= try using memory mapped access\n" 773 " exclusive= open device in exclusive mode\n" 774 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 775#endif 776#ifdef CONFIG_AUDIO_PA 777 "-audiodev pa,id=id[,prop[=value][,...]]\n" 778 " server= PulseAudio server address\n" 779 " in|out.name= source/sink device name\n" 780 " in|out.latency= desired latency in microseconds\n" 781#endif 782#ifdef CONFIG_AUDIO_SDL 783 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 784 " in|out.buffer-count= number of buffers\n" 785#endif 786#ifdef CONFIG_AUDIO_SNDIO 787 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 788#endif 789#ifdef CONFIG_SPICE 790 "-audiodev spice,id=id[,prop[=value][,...]]\n" 791#endif 792#ifdef CONFIG_DBUS_DISPLAY 793 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 794#endif 795 "-audiodev wav,id=id[,prop[=value][,...]]\n" 796 " path= path of wav file to record\n", 797 QEMU_ARCH_ALL) 798SRST 799``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 800 Adds a new audio backend driver identified by id. There are global 801 and driver specific properties. Some values can be set differently 802 for input and output, they're marked with ``in|out.``. You can set 803 the input's property with ``in.prop`` and the output's property with 804 ``out.prop``. For example: 805 806 :: 807 808 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 809 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 810 811 NOTE: parameter validation is known to be incomplete, in many cases 812 specifying an invalid option causes QEMU to print an error message 813 and continue emulation without sound. 814 815 Valid global options are: 816 817 ``id=identifier`` 818 Identifies the audio backend. 819 820 ``timer-period=period`` 821 Sets the timer period used by the audio subsystem in 822 microseconds. Default is 10000 (10 ms). 823 824 ``in|out.mixing-engine=on|off`` 825 Use QEMU's mixing engine to mix all streams inside QEMU and 826 convert audio formats when not supported by the backend. When 827 off, fixed-settings must be off too. Note that disabling this 828 option means that the selected backend must support multiple 829 streams and the audio formats used by the virtual cards, 830 otherwise you'll get no sound. It's not recommended to disable 831 this option unless you want to use 5.1 or 7.1 audio, as mixing 832 engine only supports mono and stereo audio. Default is on. 833 834 ``in|out.fixed-settings=on|off`` 835 Use fixed settings for host audio. When off, it will change 836 based on how the guest opens the sound card. In this case you 837 must not specify frequency, channels or format. Default is on. 838 839 ``in|out.frequency=frequency`` 840 Specify the frequency to use when using fixed-settings. Default 841 is 44100Hz. 842 843 ``in|out.channels=channels`` 844 Specify the number of channels to use when using fixed-settings. 845 Default is 2 (stereo). 846 847 ``in|out.format=format`` 848 Specify the sample format to use when using fixed-settings. 849 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 850 ``u32``, ``f32``. Default is ``s16``. 851 852 ``in|out.voices=voices`` 853 Specify the number of voices to use. Default is 1. 854 855 ``in|out.buffer-length=usecs`` 856 Sets the size of the buffer in microseconds. 857 858``-audiodev none,id=id[,prop[=value][,...]]`` 859 Creates a dummy backend that discards all outputs. This backend has 860 no backend specific properties. 861 862``-audiodev alsa,id=id[,prop[=value][,...]]`` 863 Creates backend using the ALSA. This backend is only available on 864 Linux. 865 866 ALSA specific options are: 867 868 ``in|out.dev=device`` 869 Specify the ALSA device to use for input and/or output. Default 870 is ``default``. 871 872 ``in|out.period-length=usecs`` 873 Sets the period length in microseconds. 874 875 ``in|out.try-poll=on|off`` 876 Attempt to use poll mode with the device. Default is on. 877 878 ``threshold=threshold`` 879 Threshold (in microseconds) when playback starts. Default is 0. 880 881``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 882 Creates a backend using Apple's Core Audio. This backend is only 883 available on Mac OS and only supports playback. 884 885 Core Audio specific options are: 886 887 ``in|out.buffer-count=count`` 888 Sets the count of the buffers. 889 890``-audiodev dsound,id=id[,prop[=value][,...]]`` 891 Creates a backend using Microsoft's DirectSound. This backend is 892 only available on Windows and only supports playback. 893 894 DirectSound specific options are: 895 896 ``latency=usecs`` 897 Add extra usecs microseconds latency to playback. Default is 898 10000 (10 ms). 899 900``-audiodev oss,id=id[,prop[=value][,...]]`` 901 Creates a backend using OSS. This backend is available on most 902 Unix-like systems. 903 904 OSS specific options are: 905 906 ``in|out.dev=device`` 907 Specify the file name of the OSS device to use. Default is 908 ``/dev/dsp``. 909 910 ``in|out.buffer-count=count`` 911 Sets the count of the buffers. 912 913 ``in|out.try-poll=on|of`` 914 Attempt to use poll mode with the device. Default is on. 915 916 ``try-mmap=on|off`` 917 Try using memory mapped device access. Default is off. 918 919 ``exclusive=on|off`` 920 Open the device in exclusive mode (vmix won't work in this 921 case). Default is off. 922 923 ``dsp-policy=policy`` 924 Sets the timing policy (between 0 and 10, where smaller number 925 means smaller latency but higher CPU usage). Use -1 to use 926 buffer sizes specified by ``buffer`` and ``buffer-count``. This 927 option is ignored if you do not have OSS 4. Default is 5. 928 929``-audiodev pa,id=id[,prop[=value][,...]]`` 930 Creates a backend using PulseAudio. This backend is available on 931 most systems. 932 933 PulseAudio specific options are: 934 935 ``server=server`` 936 Sets the PulseAudio server to connect to. 937 938 ``in|out.name=sink`` 939 Use the specified source/sink for recording/playback. 940 941 ``in|out.latency=usecs`` 942 Desired latency in microseconds. The PulseAudio server will try 943 to honor this value but actual latencies may be lower or higher. 944 945``-audiodev sdl,id=id[,prop[=value][,...]]`` 946 Creates a backend using SDL. This backend is available on most 947 systems, but you should use your platform's native backend if 948 possible. 949 950 SDL specific options are: 951 952 ``in|out.buffer-count=count`` 953 Sets the count of the buffers. 954 955``-audiodev sndio,id=id[,prop[=value][,...]]`` 956 Creates a backend using SNDIO. This backend is available on 957 OpenBSD and most other Unix-like systems. 958 959 Sndio specific options are: 960 961 ``in|out.dev=device`` 962 Specify the sndio device to use for input and/or output. Default 963 is ``default``. 964 965 ``in|out.latency=usecs`` 966 Sets the desired period length in microseconds. 967 968``-audiodev spice,id=id[,prop[=value][,...]]`` 969 Creates a backend that sends audio through SPICE. This backend 970 requires ``-spice`` and automatically selected in that case, so 971 usually you can ignore this option. This backend has no backend 972 specific properties. 973 974``-audiodev wav,id=id[,prop[=value][,...]]`` 975 Creates a backend that writes audio to a WAV file. 976 977 Backend specific options are: 978 979 ``path=path`` 980 Write recorded audio into the specified file. Default is 981 ``qemu.wav``. 982ERST 983 984DEF("device", HAS_ARG, QEMU_OPTION_device, 985 "-device driver[,prop[=value][,...]]\n" 986 " add device (based on driver)\n" 987 " prop=value,... sets driver properties\n" 988 " use '-device help' to print all possible drivers\n" 989 " use '-device driver,help' to print all possible properties\n", 990 QEMU_ARCH_ALL) 991SRST 992``-device driver[,prop[=value][,...]]`` 993 Add device driver. prop=value sets driver properties. Valid 994 properties depend on the driver. To get help on possible drivers and 995 properties, use ``-device help`` and ``-device driver,help``. 996 997 Some drivers are: 998 999``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1000 Add an IPMI BMC. This is a simulation of a hardware management 1001 interface processor that normally sits on a system. It provides a 1002 watchdog and the ability to reset and power control the system. You 1003 need to connect this to an IPMI interface to make it useful 1004 1005 The IPMI slave address to use for the BMC. The default is 0x20. This 1006 address is the BMC's address on the I2C network of management 1007 controllers. If you don't know what this means, it is safe to ignore 1008 it. 1009 1010 ``id=id`` 1011 The BMC id for interfaces to use this device. 1012 1013 ``slave_addr=val`` 1014 Define slave address to use for the BMC. The default is 0x20. 1015 1016 ``sdrfile=file`` 1017 file containing raw Sensor Data Records (SDR) data. The default 1018 is none. 1019 1020 ``fruareasize=val`` 1021 size of a Field Replaceable Unit (FRU) area. The default is 1022 1024. 1023 1024 ``frudatafile=file`` 1025 file containing raw Field Replaceable Unit (FRU) inventory data. 1026 The default is none. 1027 1028 ``guid=uuid`` 1029 value for the GUID for the BMC, in standard UUID format. If this 1030 is set, get "Get GUID" command to the BMC will return it. 1031 Otherwise "Get GUID" will return an error. 1032 1033``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1034 Add a connection to an external IPMI BMC simulator. Instead of 1035 locally emulating the BMC like the above item, instead connect to an 1036 external entity that provides the IPMI services. 1037 1038 A connection is made to an external BMC simulator. If you do this, 1039 it is strongly recommended that you use the "reconnect=" chardev 1040 option to reconnect to the simulator if the connection is lost. Note 1041 that if this is not used carefully, it can be a security issue, as 1042 the interface has the ability to send resets, NMIs, and power off 1043 the VM. It's best if QEMU makes a connection to an external 1044 simulator running on a secure port on localhost, so neither the 1045 simulator nor QEMU is exposed to any outside network. 1046 1047 See the "lanserv/README.vm" file in the OpenIPMI library for more 1048 details on the external interface. 1049 1050``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1051 Add a KCS IPMI interface on the ISA bus. This also adds a 1052 corresponding ACPI and SMBIOS entries, if appropriate. 1053 1054 ``bmc=id`` 1055 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1056 above. 1057 1058 ``ioport=val`` 1059 Define the I/O address of the interface. The default is 0xca0 1060 for KCS. 1061 1062 ``irq=val`` 1063 Define the interrupt to use. The default is 5. To disable 1064 interrupts, set this to 0. 1065 1066``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1067 Like the KCS interface, but defines a BT interface. The default port 1068 is 0xe4 and the default interrupt is 5. 1069 1070``-device pci-ipmi-kcs,bmc=id`` 1071 Add a KCS IPMI interface on the PCI bus. 1072 1073 ``bmc=id`` 1074 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1075 1076``-device pci-ipmi-bt,bmc=id`` 1077 Like the KCS interface, but defines a BT interface on the PCI bus. 1078 1079``-device intel-iommu[,option=...]`` 1080 This is only supported by ``-machine q35``, which will enable Intel VT-d 1081 emulation within the guest. It supports below options: 1082 1083 ``intremap=on|off`` (default: auto) 1084 This enables interrupt remapping feature. It's required to enable 1085 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1086 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1087 The default value is "auto", which will be decided by the mode of 1088 kernel-irqchip. 1089 1090 ``caching-mode=on|off`` (default: off) 1091 This enables caching mode for the VT-d emulated device. When 1092 caching-mode is enabled, each guest DMA buffer mapping will generate an 1093 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1094 a synchronous way. It is required for ``-device vfio-pci`` to work 1095 with the VT-d device, because host assigned devices requires to setup 1096 the DMA mapping on the host before guest DMA starts. 1097 1098 ``device-iotlb=on|off`` (default: off) 1099 This enables device-iotlb capability for the emulated VT-d device. So 1100 far virtio/vhost should be the only real user for this parameter, 1101 paired with ats=on configured for the device. 1102 1103 ``aw-bits=39|48`` (default: 39) 1104 This decides the address width of IOVA address space. The address 1105 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1106 4-level IOMMU page tables. 1107 1108 Please also refer to the wiki page for general scenarios of VT-d 1109 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1110 1111ERST 1112 1113DEF("name", HAS_ARG, QEMU_OPTION_name, 1114 "-name string1[,process=string2][,debug-threads=on|off]\n" 1115 " set the name of the guest\n" 1116 " string1 sets the window title and string2 the process name\n" 1117 " When debug-threads is enabled, individual threads are given a separate name\n" 1118 " NOTE: The thread names are for debugging and not a stable API.\n", 1119 QEMU_ARCH_ALL) 1120SRST 1121``-name name`` 1122 Sets the name of the guest. This name will be displayed in the SDL 1123 window caption. The name will also be used for the VNC server. Also 1124 optionally set the top visible process name in Linux. Naming of 1125 individual threads can also be enabled on Linux to aid debugging. 1126ERST 1127 1128DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1129 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1130 " specify machine UUID\n", QEMU_ARCH_ALL) 1131SRST 1132``-uuid uuid`` 1133 Set system UUID. 1134ERST 1135 1136DEFHEADING() 1137 1138DEFHEADING(Block device options:) 1139 1140SRST 1141The QEMU block device handling options have a long history and 1142have gone through several iterations as the feature set and complexity 1143of the block layer have grown. Many online guides to QEMU often 1144reference older and deprecated options, which can lead to confusion. 1145 1146The most explicit way to describe disks is to use a combination of 1147``-device`` to specify the hardware device and ``-blockdev`` to 1148describe the backend. The device defines what the guest sees and the 1149backend describes how QEMU handles the data. It is the only guaranteed 1150stable interface for describing block devices and as such is 1151recommended for management tools and scripting. 1152 1153The ``-drive`` option combines the device and backend into a single 1154command line option which is a more human friendly. There is however no 1155interface stability guarantee although some older board models still 1156need updating to work with the modern blockdev forms. 1157 1158Older options like ``-hda`` are essentially macros which expand into 1159``-drive`` options for various drive interfaces. The original forms 1160bake in a lot of assumptions from the days when QEMU was emulating a 1161legacy PC, they are not recommended for modern configurations. 1162 1163ERST 1164 1165DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1166 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1167DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1168SRST 1169``-fda file`` 1170 \ 1171``-fdb file`` 1172 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1173 the System Emulation Users Guide). 1174ERST 1175 1176DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1177 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1178DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1179DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1180 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1181DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1182SRST 1183``-hda file`` 1184 \ 1185``-hdb file`` 1186 \ 1187``-hdc file`` 1188 \ 1189``-hdd file`` 1190 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1191 chapter in the System Emulation Users Guide). 1192ERST 1193 1194DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1195 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1196 QEMU_ARCH_ALL) 1197SRST 1198``-cdrom file`` 1199 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1200 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1201 as filename. 1202ERST 1203 1204DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1205 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1206 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1207 " [,read-only=on|off][,auto-read-only=on|off]\n" 1208 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1209 " [,driver specific parameters...]\n" 1210 " configure a block backend\n", QEMU_ARCH_ALL) 1211SRST 1212``-blockdev option[,option[,option[,...]]]`` 1213 Define a new block driver node. Some of the options apply to all 1214 block drivers, other options are only accepted for a specific block 1215 driver. See below for a list of generic options and options for the 1216 most common block drivers. 1217 1218 Options that expect a reference to another node (e.g. ``file``) can 1219 be given in two ways. Either you specify the node name of an already 1220 existing node (file=node-name), or you define a new node inline, 1221 adding options for the referenced node after a dot 1222 (file.filename=path,file.aio=native). 1223 1224 A block driver node created with ``-blockdev`` can be used for a 1225 guest device by specifying its node name for the ``drive`` property 1226 in a ``-device`` argument that defines a block device. 1227 1228 ``Valid options for any block driver node:`` 1229 ``driver`` 1230 Specifies the block driver to use for the given node. 1231 1232 ``node-name`` 1233 This defines the name of the block driver node by which it 1234 will be referenced later. The name must be unique, i.e. it 1235 must not match the name of a different block driver node, or 1236 (if you use ``-drive`` as well) the ID of a drive. 1237 1238 If no node name is specified, it is automatically generated. 1239 The generated node name is not intended to be predictable 1240 and changes between QEMU invocations. For the top level, an 1241 explicit node name must be specified. 1242 1243 ``read-only`` 1244 Open the node read-only. Guest write attempts will fail. 1245 1246 Note that some block drivers support only read-only access, 1247 either generally or in certain configurations. In this case, 1248 the default value ``read-only=off`` does not work and the 1249 option must be specified explicitly. 1250 1251 ``auto-read-only`` 1252 If ``auto-read-only=on`` is set, QEMU may fall back to 1253 read-only usage even when ``read-only=off`` is requested, or 1254 even switch between modes as needed, e.g. depending on 1255 whether the image file is writable or whether a writing user 1256 is attached to the node. 1257 1258 ``force-share`` 1259 Override the image locking system of QEMU by forcing the 1260 node to utilize weaker shared access for permissions where 1261 it would normally request exclusive access. When there is 1262 the potential for multiple instances to have the same file 1263 open (whether this invocation of QEMU is the first or the 1264 second instance), both instances must permit shared access 1265 for the second instance to succeed at opening the file. 1266 1267 Enabling ``force-share=on`` requires ``read-only=on``. 1268 1269 ``cache.direct`` 1270 The host page cache can be avoided with ``cache.direct=on``. 1271 This will attempt to do disk IO directly to the guest's 1272 memory. QEMU may still perform an internal copy of the data. 1273 1274 ``cache.no-flush`` 1275 In case you don't care about data integrity over host 1276 failures, you can use ``cache.no-flush=on``. This option 1277 tells QEMU that it never needs to write any data to the disk 1278 but can instead keep things in cache. If anything goes 1279 wrong, like your host losing power, the disk storage getting 1280 disconnected accidentally, etc. your image will most 1281 probably be rendered unusable. 1282 1283 ``discard=discard`` 1284 discard is one of "ignore" (or "off") or "unmap" (or "on") 1285 and controls whether ``discard`` (also known as ``trim`` or 1286 ``unmap``) requests are ignored or passed to the filesystem. 1287 Some machine types may not support discard requests. 1288 1289 ``detect-zeroes=detect-zeroes`` 1290 detect-zeroes is "off", "on" or "unmap" and enables the 1291 automatic conversion of plain zero writes by the OS to 1292 driver specific optimized zero write commands. You may even 1293 choose "unmap" if discard is set to "unmap" to allow a zero 1294 write to be converted to an ``unmap`` operation. 1295 1296 ``Driver-specific options for file`` 1297 This is the protocol-level block driver for accessing regular 1298 files. 1299 1300 ``filename`` 1301 The path to the image file in the local filesystem 1302 1303 ``aio`` 1304 Specifies the AIO backend (threads/native/io_uring, 1305 default: threads) 1306 1307 ``locking`` 1308 Specifies whether the image file is protected with Linux OFD 1309 / POSIX locks. The default is to use the Linux Open File 1310 Descriptor API if available, otherwise no lock is applied. 1311 (auto/on/off, default: auto) 1312 1313 Example: 1314 1315 :: 1316 1317 -blockdev driver=file,node-name=disk,filename=disk.img 1318 1319 ``Driver-specific options for raw`` 1320 This is the image format block driver for raw images. It is 1321 usually stacked on top of a protocol level block driver such as 1322 ``file``. 1323 1324 ``file`` 1325 Reference to or definition of the data source block driver 1326 node (e.g. a ``file`` driver node) 1327 1328 Example 1: 1329 1330 :: 1331 1332 -blockdev driver=file,node-name=disk_file,filename=disk.img 1333 -blockdev driver=raw,node-name=disk,file=disk_file 1334 1335 Example 2: 1336 1337 :: 1338 1339 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1340 1341 ``Driver-specific options for qcow2`` 1342 This is the image format block driver for qcow2 images. It is 1343 usually stacked on top of a protocol level block driver such as 1344 ``file``. 1345 1346 ``file`` 1347 Reference to or definition of the data source block driver 1348 node (e.g. a ``file`` driver node) 1349 1350 ``backing`` 1351 Reference to or definition of the backing file block device 1352 (default is taken from the image file). It is allowed to 1353 pass ``null`` here in order to disable the default backing 1354 file. 1355 1356 ``lazy-refcounts`` 1357 Whether to enable the lazy refcounts feature (on/off; 1358 default is taken from the image file) 1359 1360 ``cache-size`` 1361 The maximum total size of the L2 table and refcount block 1362 caches in bytes (default: the sum of l2-cache-size and 1363 refcount-cache-size) 1364 1365 ``l2-cache-size`` 1366 The maximum size of the L2 table cache in bytes (default: if 1367 cache-size is not specified - 32M on Linux platforms, and 8M 1368 on non-Linux platforms; otherwise, as large as possible 1369 within the cache-size, while permitting the requested or the 1370 minimal refcount cache size) 1371 1372 ``refcount-cache-size`` 1373 The maximum size of the refcount block cache in bytes 1374 (default: 4 times the cluster size; or if cache-size is 1375 specified, the part of it which is not used for the L2 1376 cache) 1377 1378 ``cache-clean-interval`` 1379 Clean unused entries in the L2 and refcount caches. The 1380 interval is in seconds. The default value is 600 on 1381 supporting platforms, and 0 on other platforms. Setting it 1382 to 0 disables this feature. 1383 1384 ``pass-discard-request`` 1385 Whether discard requests to the qcow2 device should be 1386 forwarded to the data source (on/off; default: on if 1387 discard=unmap is specified, off otherwise) 1388 1389 ``pass-discard-snapshot`` 1390 Whether discard requests for the data source should be 1391 issued when a snapshot operation (e.g. deleting a snapshot) 1392 frees clusters in the qcow2 file (on/off; default: on) 1393 1394 ``pass-discard-other`` 1395 Whether discard requests for the data source should be 1396 issued on other occasions where a cluster gets freed 1397 (on/off; default: off) 1398 1399 ``overlap-check`` 1400 Which overlap checks to perform for writes to the image 1401 (none/constant/cached/all; default: cached). For details or 1402 finer granularity control refer to the QAPI documentation of 1403 ``blockdev-add``. 1404 1405 Example 1: 1406 1407 :: 1408 1409 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1410 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1411 1412 Example 2: 1413 1414 :: 1415 1416 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1417 1418 ``Driver-specific options for other drivers`` 1419 Please refer to the QAPI documentation of the ``blockdev-add`` 1420 QMP command. 1421ERST 1422 1423DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1424 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1425 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1426 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1427 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1428 " [,aio=threads|native|io_uring]\n" 1429 " [,readonly=on|off][,copy-on-read=on|off]\n" 1430 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1431 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1432 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1433 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1434 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1435 " [[,iops_size=is]]\n" 1436 " [[,group=g]]\n" 1437 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1438SRST 1439``-drive option[,option[,option[,...]]]`` 1440 Define a new drive. This includes creating a block driver node (the 1441 backend) as well as a guest device, and is mostly a shortcut for 1442 defining the corresponding ``-blockdev`` and ``-device`` options. 1443 1444 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1445 In addition, it knows the following options: 1446 1447 ``file=file`` 1448 This option defines which disk image (see the :ref:`disk images` 1449 chapter in the System Emulation Users Guide) to use with this drive. 1450 If the filename contains comma, you must double it (for instance, 1451 "file=my,,file" to use file "my,file"). 1452 1453 Special files such as iSCSI devices can be specified using 1454 protocol specific URLs. See the section for "Device URL Syntax" 1455 for more information. 1456 1457 ``if=interface`` 1458 This option defines on which type on interface the drive is 1459 connected. Available types are: ide, scsi, sd, mtd, floppy, 1460 pflash, virtio, none. 1461 1462 ``bus=bus,unit=unit`` 1463 These options define where is connected the drive by defining 1464 the bus number and the unit id. 1465 1466 ``index=index`` 1467 This option defines where the drive is connected by using an 1468 index in the list of available connectors of a given interface 1469 type. 1470 1471 ``media=media`` 1472 This option defines the type of the media: disk or cdrom. 1473 1474 ``snapshot=snapshot`` 1475 snapshot is "on" or "off" and controls snapshot mode for the 1476 given drive (see ``-snapshot``). 1477 1478 ``cache=cache`` 1479 cache is "none", "writeback", "unsafe", "directsync" or 1480 "writethrough" and controls how the host cache is used to access 1481 block data. This is a shortcut that sets the ``cache.direct`` 1482 and ``cache.no-flush`` options (as in ``-blockdev``), and 1483 additionally ``cache.writeback``, which provides a default for 1484 the ``write-cache`` option of block guest devices (as in 1485 ``-device``). The modes correspond to the following settings: 1486 1487 ============= =============== ============ ============== 1488 \ cache.writeback cache.direct cache.no-flush 1489 ============= =============== ============ ============== 1490 writeback on off off 1491 none on on off 1492 writethrough off off off 1493 directsync off on off 1494 unsafe on off on 1495 ============= =============== ============ ============== 1496 1497 The default mode is ``cache=writeback``. 1498 1499 ``aio=aio`` 1500 aio is "threads", "native", or "io_uring" and selects between pthread 1501 based disk I/O, native Linux AIO, or Linux io_uring API. 1502 1503 ``format=format`` 1504 Specify which disk format will be used rather than detecting the 1505 format. Can be used to specify format=raw to avoid interpreting 1506 an untrusted format header. 1507 1508 ``werror=action,rerror=action`` 1509 Specify which action to take on write and read errors. Valid 1510 actions are: "ignore" (ignore the error and try to continue), 1511 "stop" (pause QEMU), "report" (report the error to the guest), 1512 "enospc" (pause QEMU only if the host disk is full; report the 1513 error to the guest otherwise). The default setting is 1514 ``werror=enospc`` and ``rerror=report``. 1515 1516 ``copy-on-read=copy-on-read`` 1517 copy-on-read is "on" or "off" and enables whether to copy read 1518 backing file sectors into the image file. 1519 1520 ``bps=b,bps_rd=r,bps_wr=w`` 1521 Specify bandwidth throttling limits in bytes per second, either 1522 for all request types or for reads or writes only. Small values 1523 can lead to timeouts or hangs inside the guest. A safe minimum 1524 for disks is 2 MB/s. 1525 1526 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1527 Specify bursts in bytes per second, either for all request types 1528 or for reads or writes only. Bursts allow the guest I/O to spike 1529 above the limit temporarily. 1530 1531 ``iops=i,iops_rd=r,iops_wr=w`` 1532 Specify request rate limits in requests per second, either for 1533 all request types or for reads or writes only. 1534 1535 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1536 Specify bursts in requests per second, either for all request 1537 types or for reads or writes only. Bursts allow the guest I/O to 1538 spike above the limit temporarily. 1539 1540 ``iops_size=is`` 1541 Let every is bytes of a request count as a new request for iops 1542 throttling purposes. Use this option to prevent guests from 1543 circumventing iops limits by sending fewer but larger requests. 1544 1545 ``group=g`` 1546 Join a throttling quota group with given name g. All drives that 1547 are members of the same group are accounted for together. Use 1548 this option to prevent guests from circumventing throttling 1549 limits by using many small disks instead of a single larger 1550 disk. 1551 1552 By default, the ``cache.writeback=on`` mode is used. It will report 1553 data writes as completed as soon as the data is present in the host 1554 page cache. This is safe as long as your guest OS makes sure to 1555 correctly flush disk caches where needed. If your guest OS does not 1556 handle volatile disk write caches correctly and your host crashes or 1557 loses power, then the guest may experience data corruption. 1558 1559 For such guests, you should consider using ``cache.writeback=off``. 1560 This means that the host page cache will be used to read and write 1561 data, but write notification will be sent to the guest only after 1562 QEMU has made sure to flush each write to the disk. Be aware that 1563 this has a major impact on performance. 1564 1565 When using the ``-snapshot`` option, unsafe caching is always used. 1566 1567 Copy-on-read avoids accessing the same backing file sectors 1568 repeatedly and is useful when the backing file is over a slow 1569 network. By default copy-on-read is off. 1570 1571 Instead of ``-cdrom`` you can use: 1572 1573 .. parsed-literal:: 1574 1575 |qemu_system| -drive file=file,index=2,media=cdrom 1576 1577 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1578 1579 .. parsed-literal:: 1580 1581 |qemu_system| -drive file=file,index=0,media=disk 1582 |qemu_system| -drive file=file,index=1,media=disk 1583 |qemu_system| -drive file=file,index=2,media=disk 1584 |qemu_system| -drive file=file,index=3,media=disk 1585 1586 You can open an image using pre-opened file descriptors from an fd 1587 set: 1588 1589 .. parsed-literal:: 1590 1591 |qemu_system| \\ 1592 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1593 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1594 -drive file=/dev/fdset/2,index=0,media=disk 1595 1596 You can connect a CDROM to the slave of ide0: 1597 1598 .. parsed-literal:: 1599 1600 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1601 1602 If you don't specify the "file=" argument, you define an empty 1603 drive: 1604 1605 .. parsed-literal:: 1606 1607 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1608 1609 Instead of ``-fda``, ``-fdb``, you can use: 1610 1611 .. parsed-literal:: 1612 1613 |qemu_system_x86| -drive file=file,index=0,if=floppy 1614 |qemu_system_x86| -drive file=file,index=1,if=floppy 1615 1616 By default, interface is "ide" and index is automatically 1617 incremented: 1618 1619 .. parsed-literal:: 1620 1621 |qemu_system_x86| -drive file=a -drive file=b 1622 1623 is interpreted like: 1624 1625 .. parsed-literal:: 1626 1627 |qemu_system_x86| -hda a -hdb b 1628ERST 1629 1630DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1631 "-mtdblock file use 'file' as on-board Flash memory image\n", 1632 QEMU_ARCH_ALL) 1633SRST 1634``-mtdblock file`` 1635 Use file as on-board Flash memory image. 1636ERST 1637 1638DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1639 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1640SRST 1641``-sd file`` 1642 Use file as SecureDigital card image. 1643ERST 1644 1645DEF("snapshot", 0, QEMU_OPTION_snapshot, 1646 "-snapshot write to temporary files instead of disk image files\n", 1647 QEMU_ARCH_ALL) 1648SRST 1649``-snapshot`` 1650 Write to temporary files instead of disk image files. In this case, 1651 the raw disk image you use is not written back. You can however 1652 force the write back by pressing C-a s (see the :ref:`disk images` 1653 chapter in the System Emulation Users Guide). 1654 1655 .. warning:: 1656 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1657 to manually create snapshot images to attach to your blockdev). 1658 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1659 can use the 'snapshot' property on your drive declarations 1660 instead of this global option. 1661 1662ERST 1663 1664DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1665 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1666 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1667 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1668 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1669 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1670 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1671 " [[,throttling.iops-size=is]]\n" 1672 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1673 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1674 "-fsdev synth,id=id\n", 1675 QEMU_ARCH_ALL) 1676 1677SRST 1678``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1679 \ 1680``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1681 \ 1682``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1683 \ 1684``-fsdev synth,id=id[,readonly=on]`` 1685 Define a new file system device. Valid options are: 1686 1687 ``local`` 1688 Accesses to the filesystem are done by QEMU. 1689 1690 ``proxy`` 1691 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1692 1693 ``synth`` 1694 Synthetic filesystem, only used by QTests. 1695 1696 ``id=id`` 1697 Specifies identifier for this device. 1698 1699 ``path=path`` 1700 Specifies the export path for the file system device. Files 1701 under this path will be available to the 9p client on the guest. 1702 1703 ``security_model=security_model`` 1704 Specifies the security model to be used for this export path. 1705 Supported security models are "passthrough", "mapped-xattr", 1706 "mapped-file" and "none". In "passthrough" security model, files 1707 are stored using the same credentials as they are created on the 1708 guest. This requires QEMU to run as root. In "mapped-xattr" 1709 security model, some of the file attributes like uid, gid, mode 1710 bits and link target are stored as file attributes. For 1711 "mapped-file" these attributes are stored in the hidden 1712 .virtfs\_metadata directory. Directories exported by this 1713 security model cannot interact with other unix tools. "none" 1714 security model is same as passthrough except the sever won't 1715 report failures if it fails to set file attributes like 1716 ownership. Security model is mandatory only for local fsdriver. 1717 Other fsdrivers (like proxy) don't take security model as a 1718 parameter. 1719 1720 ``writeout=writeout`` 1721 This is an optional argument. The only supported value is 1722 "immediate". This means that host page cache will be used to 1723 read and write data but write notification will be sent to the 1724 guest only when the data has been reported as written by the 1725 storage subsystem. 1726 1727 ``readonly=on`` 1728 Enables exporting 9p share as a readonly mount for guests. By 1729 default read-write access is given. 1730 1731 ``socket=socket`` 1732 Enables proxy filesystem driver to use passed socket file for 1733 communicating with virtfs-proxy-helper(1). 1734 1735 ``sock_fd=sock_fd`` 1736 Enables proxy filesystem driver to use passed socket descriptor 1737 for communicating with virtfs-proxy-helper(1). Usually a helper 1738 like libvirt will create socketpair and pass one of the fds as 1739 sock\_fd. 1740 1741 ``fmode=fmode`` 1742 Specifies the default mode for newly created files on the host. 1743 Works only with security models "mapped-xattr" and 1744 "mapped-file". 1745 1746 ``dmode=dmode`` 1747 Specifies the default mode for newly created directories on the 1748 host. Works only with security models "mapped-xattr" and 1749 "mapped-file". 1750 1751 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1752 Specify bandwidth throttling limits in bytes per second, either 1753 for all request types or for reads or writes only. 1754 1755 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1756 Specify bursts in bytes per second, either for all request types 1757 or for reads or writes only. Bursts allow the guest I/O to spike 1758 above the limit temporarily. 1759 1760 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1761 Specify request rate limits in requests per second, either for 1762 all request types or for reads or writes only. 1763 1764 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1765 Specify bursts in requests per second, either for all request 1766 types or for reads or writes only. Bursts allow the guest I/O to 1767 spike above the limit temporarily. 1768 1769 ``throttling.iops-size=is`` 1770 Let every is bytes of a request count as a new request for iops 1771 throttling purposes. 1772 1773 -fsdev option is used along with -device driver "virtio-9p-...". 1774 1775``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1776 Options for virtio-9p-... driver are: 1777 1778 ``type`` 1779 Specifies the variant to be used. Supported values are "pci", 1780 "ccw" or "device", depending on the machine type. 1781 1782 ``fsdev=id`` 1783 Specifies the id value specified along with -fsdev option. 1784 1785 ``mount_tag=mount_tag`` 1786 Specifies the tag name to be used by the guest to mount this 1787 export point. 1788ERST 1789 1790DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1791 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1792 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1793 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1794 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1795 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1796 QEMU_ARCH_ALL) 1797 1798SRST 1799``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1800 \ 1801``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1802 \ 1803``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1804 \ 1805``-virtfs synth,mount_tag=mount_tag`` 1806 Define a new virtual filesystem device and expose it to the guest using 1807 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1808 directory on host is made directly accessible by guest as a pass-through 1809 file system by using the 9P network protocol for communication between 1810 host and guests, if desired even accessible, shared by several guests 1811 simultaneously. 1812 1813 Note that ``-virtfs`` is actually just a convenience shortcut for its 1814 generalized form ``-fsdev -device virtio-9p-pci``. 1815 1816 The general form of pass-through file system options are: 1817 1818 ``local`` 1819 Accesses to the filesystem are done by QEMU. 1820 1821 ``proxy`` 1822 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1823 1824 ``synth`` 1825 Synthetic filesystem, only used by QTests. 1826 1827 ``id=id`` 1828 Specifies identifier for the filesystem device 1829 1830 ``path=path`` 1831 Specifies the export path for the file system device. Files 1832 under this path will be available to the 9p client on the guest. 1833 1834 ``security_model=security_model`` 1835 Specifies the security model to be used for this export path. 1836 Supported security models are "passthrough", "mapped-xattr", 1837 "mapped-file" and "none". In "passthrough" security model, files 1838 are stored using the same credentials as they are created on the 1839 guest. This requires QEMU to run as root. In "mapped-xattr" 1840 security model, some of the file attributes like uid, gid, mode 1841 bits and link target are stored as file attributes. For 1842 "mapped-file" these attributes are stored in the hidden 1843 .virtfs\_metadata directory. Directories exported by this 1844 security model cannot interact with other unix tools. "none" 1845 security model is same as passthrough except the sever won't 1846 report failures if it fails to set file attributes like 1847 ownership. Security model is mandatory only for local fsdriver. 1848 Other fsdrivers (like proxy) don't take security model as a 1849 parameter. 1850 1851 ``writeout=writeout`` 1852 This is an optional argument. The only supported value is 1853 "immediate". This means that host page cache will be used to 1854 read and write data but write notification will be sent to the 1855 guest only when the data has been reported as written by the 1856 storage subsystem. 1857 1858 ``readonly=on`` 1859 Enables exporting 9p share as a readonly mount for guests. By 1860 default read-write access is given. 1861 1862 ``socket=socket`` 1863 Enables proxy filesystem driver to use passed socket file for 1864 communicating with virtfs-proxy-helper(1). Usually a helper like 1865 libvirt will create socketpair and pass one of the fds as 1866 sock\_fd. 1867 1868 ``sock_fd`` 1869 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1870 socket descriptor for interfacing with virtfs-proxy-helper(1). 1871 1872 ``fmode=fmode`` 1873 Specifies the default mode for newly created files on the host. 1874 Works only with security models "mapped-xattr" and 1875 "mapped-file". 1876 1877 ``dmode=dmode`` 1878 Specifies the default mode for newly created directories on the 1879 host. Works only with security models "mapped-xattr" and 1880 "mapped-file". 1881 1882 ``mount_tag=mount_tag`` 1883 Specifies the tag name to be used by the guest to mount this 1884 export point. 1885 1886 ``multidevs=multidevs`` 1887 Specifies how to deal with multiple devices being shared with a 1888 9p export. Supported behaviours are either "remap", "forbid" or 1889 "warn". The latter is the default behaviour on which virtfs 9p 1890 expects only one device to be shared with the same export, and 1891 if more than one device is shared and accessed via the same 9p 1892 export then only a warning message is logged (once) by qemu on 1893 host side. In order to avoid file ID collisions on guest you 1894 should either create a separate virtfs export for each device to 1895 be shared with guests (recommended way) or you might use "remap" 1896 instead which allows you to share multiple devices with only one 1897 export instead, which is achieved by remapping the original 1898 inode numbers from host to guest in a way that would prevent 1899 such collisions. Remapping inodes in such use cases is required 1900 because the original device IDs from host are never passed and 1901 exposed on guest. Instead all files of an export shared with 1902 virtfs always share the same device id on guest. So two files 1903 with identical inode numbers but from actually different devices 1904 on host would otherwise cause a file ID collision and hence 1905 potential misbehaviours on guest. "forbid" on the other hand 1906 assumes like "warn" that only one device is shared by the same 1907 export, however it will not only log a warning message but also 1908 deny access to additional devices on guest. Note though that 1909 "forbid" does currently not block all possible file access 1910 operations (e.g. readdir() would still return entries from other 1911 devices). 1912ERST 1913 1914DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1915 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1916 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1917 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1918 " [,timeout=timeout]\n" 1919 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1920 1921SRST 1922``-iscsi`` 1923 Configure iSCSI session parameters. 1924ERST 1925 1926DEFHEADING() 1927 1928DEFHEADING(USB convenience options:) 1929 1930DEF("usb", 0, QEMU_OPTION_usb, 1931 "-usb enable on-board USB host controller (if not enabled by default)\n", 1932 QEMU_ARCH_ALL) 1933SRST 1934``-usb`` 1935 Enable USB emulation on machine types with an on-board USB host 1936 controller (if not enabled by default). Note that on-board USB host 1937 controllers may not support USB 3.0. In this case 1938 ``-device qemu-xhci`` can be used instead on machines with PCI. 1939ERST 1940 1941DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1942 "-usbdevice name add the host or guest USB device 'name'\n", 1943 QEMU_ARCH_ALL) 1944SRST 1945``-usbdevice devname`` 1946 Add the USB device devname, and enable an on-board USB controller 1947 if possible and necessary (just like it can be done via 1948 ``-machine usb=on``). Note that this option is mainly intended for 1949 the user's convenience only. More fine-grained control can be 1950 achieved by selecting a USB host controller (if necessary) and the 1951 desired USB device via the ``-device`` option instead. For example, 1952 instead of using ``-usbdevice mouse`` it is possible to use 1953 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1954 to a USB 3.0 controller instead (at least on machines that support 1955 PCI and do not have an USB controller enabled by default yet). 1956 For more details, see the chapter about 1957 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1958 Possible devices for devname are: 1959 1960 ``braille`` 1961 Braille device. This will use BrlAPI to display the braille 1962 output on a real or fake device (i.e. it also creates a 1963 corresponding ``braille`` chardev automatically beside the 1964 ``usb-braille`` USB device). 1965 1966 ``keyboard`` 1967 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1968 1969 ``mouse`` 1970 Virtual Mouse. This will override the PS/2 mouse emulation when 1971 activated. 1972 1973 ``tablet`` 1974 Pointer device that uses absolute coordinates (like a 1975 touchscreen). This means QEMU is able to report the mouse 1976 position without having to grab the mouse. Also overrides the 1977 PS/2 mouse emulation when activated. 1978 1979 ``wacom-tablet`` 1980 Wacom PenPartner USB tablet. 1981 1982 1983ERST 1984 1985DEFHEADING() 1986 1987DEFHEADING(Display options:) 1988 1989DEF("display", HAS_ARG, QEMU_OPTION_display, 1990#if defined(CONFIG_SPICE) 1991 "-display spice-app[,gl=on|off]\n" 1992#endif 1993#if defined(CONFIG_SDL) 1994 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 1995 " [,window-close=on|off]\n" 1996#endif 1997#if defined(CONFIG_GTK) 1998 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1999 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2000 " [,show-menubar=on|off]\n" 2001#endif 2002#if defined(CONFIG_VNC) 2003 "-display vnc=<display>[,<optargs>]\n" 2004#endif 2005#if defined(CONFIG_CURSES) 2006 "-display curses[,charset=<encoding>]\n" 2007#endif 2008#if defined(CONFIG_COCOA) 2009 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2010#endif 2011#if defined(CONFIG_OPENGL) 2012 "-display egl-headless[,rendernode=<file>]\n" 2013#endif 2014#if defined(CONFIG_DBUS_DISPLAY) 2015 "-display dbus[,addr=<dbusaddr>]\n" 2016 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2017#endif 2018#if defined(CONFIG_COCOA) 2019 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 2020#endif 2021 "-display none\n" 2022 " select display backend type\n" 2023 " The default display is equivalent to\n " 2024#if defined(CONFIG_GTK) 2025 "\"-display gtk\"\n" 2026#elif defined(CONFIG_SDL) 2027 "\"-display sdl\"\n" 2028#elif defined(CONFIG_COCOA) 2029 "\"-display cocoa\"\n" 2030#elif defined(CONFIG_VNC) 2031 "\"-vnc localhost:0,to=99,id=default\"\n" 2032#else 2033 "\"-display none\"\n" 2034#endif 2035 , QEMU_ARCH_ALL) 2036SRST 2037``-display type`` 2038 Select type of display to use. Use ``-display help`` to list the available 2039 display types. Valid values for type are 2040 2041 ``spice-app[,gl=on|off]`` 2042 Start QEMU as a Spice server and launch the default Spice client 2043 application. The Spice server will redirect the serial consoles 2044 and QEMU monitors. (Since 4.0) 2045 2046 ``dbus`` 2047 Export the display over D-Bus interfaces. (Since 7.0) 2048 2049 The connection is registered with the "org.qemu" name (and queued when 2050 already owned). 2051 2052 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2053 2054 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2055 2056 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2057 will share framebuffers with DMABUF file descriptors). 2058 2059 ``sdl`` 2060 Display video output via SDL (usually in a separate graphics 2061 window; see the SDL documentation for other possibilities). 2062 Valid parameters are: 2063 2064 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2065 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2066 either ``lshift-lctrl-lalt`` or ``rctrl``. 2067 2068 ``gl=on|off|core|es`` : Use OpenGL for displaying 2069 2070 ``show-cursor=on|off`` : Force showing the mouse cursor 2071 2072 ``window-close=on|off`` : Allow to quit qemu with window close button 2073 2074 ``gtk`` 2075 Display video output in a GTK window. This interface provides 2076 drop-down menus and other UI elements to configure and control 2077 the VM during runtime. Valid parameters are: 2078 2079 ``full-screen=on|off`` : Start in fullscreen mode 2080 2081 ``gl=on|off`` : Use OpenGL for displaying 2082 2083 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2084 2085 ``show-tabs=on|off`` : Display the tab bar for switching between the 2086 various graphical interfaces (e.g. VGA and 2087 virtual console character devices) by default. 2088 2089 ``show-cursor=on|off`` : Force showing the mouse cursor 2090 2091 ``window-close=on|off`` : Allow to quit qemu with window close button 2092 2093 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2094 2095 ``curses[,charset=<encoding>]`` 2096 Display video output via curses. For graphics device models 2097 which support a text mode, QEMU can display this output using a 2098 curses/ncurses interface. Nothing is displayed when the graphics 2099 device is in graphical mode or if the graphics device does not 2100 support a text mode. Generally only the VGA device models 2101 support text mode. The font charset used by the guest can be 2102 specified with the ``charset`` option, for example 2103 ``charset=CP850`` for IBM CP850 encoding. The default is 2104 ``CP437``. 2105 2106 ``cocoa`` 2107 Display video output in a Cocoa window. Mac only. This interface 2108 provides drop-down menus and other UI elements to configure and 2109 control the VM during runtime. Valid parameters are: 2110 2111 ``show-cursor=on|off`` : Force showing the mouse cursor 2112 2113 ``left-command-key=on|off`` : Disable forwarding left command key to host 2114 2115 ``egl-headless[,rendernode=<file>]`` 2116 Offload all OpenGL operations to a local DRI device. For any 2117 graphical display, this display needs to be paired with either 2118 VNC or SPICE displays. 2119 2120 ``vnc=<display>`` 2121 Start a VNC server on display <display> 2122 2123 ``none`` 2124 Do not display video output. The guest will still see an 2125 emulated graphics card, but its output will not be displayed to 2126 the QEMU user. This option differs from the -nographic option in 2127 that it only affects what is done with video output; -nographic 2128 also changes the destination of the serial and parallel port 2129 data. 2130ERST 2131 2132DEF("nographic", 0, QEMU_OPTION_nographic, 2133 "-nographic disable graphical output and redirect serial I/Os to console\n", 2134 QEMU_ARCH_ALL) 2135SRST 2136``-nographic`` 2137 Normally, if QEMU is compiled with graphical window support, it 2138 displays output such as guest graphics, guest console, and the QEMU 2139 monitor in a window. With this option, you can totally disable 2140 graphical output so that QEMU is a simple command line application. 2141 The emulated serial port is redirected on the console and muxed with 2142 the monitor (unless redirected elsewhere explicitly). Therefore, you 2143 can still use QEMU to debug a Linux kernel with a serial console. 2144 Use C-a h for help on switching between the console and monitor. 2145ERST 2146 2147#ifdef CONFIG_SPICE 2148DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2149 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2150 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2151 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2152 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2153 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2154 " [,tls-ciphers=<list>]\n" 2155 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2156 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2157 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2158 " [,password-secret=<secret-id>]\n" 2159 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2160 " [,jpeg-wan-compression=[auto|never|always]]\n" 2161 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2162 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2163 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2164 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2165 " [,gl=[on|off]][,rendernode=<file>]\n" 2166 " enable spice\n" 2167 " at least one of {port, tls-port} is mandatory\n", 2168 QEMU_ARCH_ALL) 2169#endif 2170SRST 2171``-spice option[,option[,...]]`` 2172 Enable the spice remote desktop protocol. Valid options are 2173 2174 ``port=<nr>`` 2175 Set the TCP port spice is listening on for plaintext channels. 2176 2177 ``addr=<addr>`` 2178 Set the IP address spice is listening on. Default is any 2179 address. 2180 2181 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2182 Force using the specified IP version. 2183 2184 ``password-secret=<secret-id>`` 2185 Set the ID of the ``secret`` object containing the password 2186 you need to authenticate. 2187 2188 ``sasl=on|off`` 2189 Require that the client use SASL to authenticate with the spice. 2190 The exact choice of authentication method used is controlled 2191 from the system / user's SASL configuration file for the 'qemu' 2192 service. This is typically found in /etc/sasl2/qemu.conf. If 2193 running QEMU as an unprivileged user, an environment variable 2194 SASL\_CONF\_PATH can be used to make it search alternate 2195 locations for the service config. While some SASL auth methods 2196 can also provide data encryption (eg GSSAPI), it is recommended 2197 that SASL always be combined with the 'tls' and 'x509' settings 2198 to enable use of SSL and server certificates. This ensures a 2199 data encryption preventing compromise of authentication 2200 credentials. 2201 2202 ``disable-ticketing=on|off`` 2203 Allow client connects without authentication. 2204 2205 ``disable-copy-paste=on|off`` 2206 Disable copy paste between the client and the guest. 2207 2208 ``disable-agent-file-xfer=on|off`` 2209 Disable spice-vdagent based file-xfer between the client and the 2210 guest. 2211 2212 ``tls-port=<nr>`` 2213 Set the TCP port spice is listening on for encrypted channels. 2214 2215 ``x509-dir=<dir>`` 2216 Set the x509 file directory. Expects same filenames as -vnc 2217 $display,x509=$dir 2218 2219 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2220 The x509 file names can also be configured individually. 2221 2222 ``tls-ciphers=<list>`` 2223 Specify which ciphers to use. 2224 2225 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2226 Force specific channel to be used with or without TLS 2227 encryption. The options can be specified multiple times to 2228 configure multiple channels. The special name "default" can be 2229 used to set the default mode. For channels which are not 2230 explicitly forced into one mode the spice client is allowed to 2231 pick tls/plaintext as he pleases. 2232 2233 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2234 Configure image compression (lossless). Default is auto\_glz. 2235 2236 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2237 Configure wan image compression (lossy for slow links). Default 2238 is auto. 2239 2240 ``streaming-video=[off|all|filter]`` 2241 Configure video stream detection. Default is off. 2242 2243 ``agent-mouse=[on|off]`` 2244 Enable/disable passing mouse events via vdagent. Default is on. 2245 2246 ``playback-compression=[on|off]`` 2247 Enable/disable audio stream compression (using celt 0.5.1). 2248 Default is on. 2249 2250 ``seamless-migration=[on|off]`` 2251 Enable/disable spice seamless migration. Default is off. 2252 2253 ``gl=[on|off]`` 2254 Enable/disable OpenGL context. Default is off. 2255 2256 ``rendernode=<file>`` 2257 DRM render node for OpenGL rendering. If not specified, it will 2258 pick the first available. (Since 2.9) 2259ERST 2260 2261DEF("portrait", 0, QEMU_OPTION_portrait, 2262 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2263 QEMU_ARCH_ALL) 2264SRST 2265``-portrait`` 2266 Rotate graphical output 90 deg left (only PXA LCD). 2267ERST 2268 2269DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2270 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2271 QEMU_ARCH_ALL) 2272SRST 2273``-rotate deg`` 2274 Rotate graphical output some deg left (only PXA LCD). 2275ERST 2276 2277DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2278 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2279 " select video card type\n", QEMU_ARCH_ALL) 2280SRST 2281``-vga type`` 2282 Select type of VGA card to emulate. Valid values for type are 2283 2284 ``cirrus`` 2285 Cirrus Logic GD5446 Video card. All Windows versions starting 2286 from Windows 95 should recognize and use this graphic card. For 2287 optimal performances, use 16 bit color depth in the guest and 2288 the host OS. (This card was the default before QEMU 2.2) 2289 2290 ``std`` 2291 Standard VGA card with Bochs VBE extensions. If your guest OS 2292 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2293 you want to use high resolution modes (>= 1280x1024x16) then you 2294 should use this option. (This card is the default since QEMU 2295 2.2) 2296 2297 ``vmware`` 2298 VMWare SVGA-II compatible adapter. Use it if you have 2299 sufficiently recent XFree86/XOrg server or Windows guest with a 2300 driver for this card. 2301 2302 ``qxl`` 2303 QXL paravirtual graphic card. It is VGA compatible (including 2304 VESA 2.0 VBE support). Works best with qxl guest drivers 2305 installed though. Recommended choice when using the spice 2306 protocol. 2307 2308 ``tcx`` 2309 (sun4m only) Sun TCX framebuffer. This is the default 2310 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2311 colour depths at a fixed resolution of 1024x768. 2312 2313 ``cg3`` 2314 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2315 framebuffer for sun4m machines available in both 1024x768 2316 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2317 wishing to run older Solaris versions. 2318 2319 ``virtio`` 2320 Virtio VGA card. 2321 2322 ``none`` 2323 Disable VGA card. 2324ERST 2325 2326DEF("full-screen", 0, QEMU_OPTION_full_screen, 2327 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2328SRST 2329``-full-screen`` 2330 Start in full screen. 2331ERST 2332 2333DEF("g", HAS_ARG, QEMU_OPTION_g , 2334 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2335 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2336SRST 2337``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2338 Set the initial graphical resolution and depth (PPC, SPARC only). 2339 2340 For PPC the default is 800x600x32. 2341 2342 For SPARC with the TCX graphics device, the default is 1024x768x8 2343 with the option of 1024x768x24. For cgthree, the default is 2344 1024x768x8 with the option of 1152x900x8 for people who wish to use 2345 OBP. 2346ERST 2347 2348DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2349 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2350SRST 2351``-vnc display[,option[,option[,...]]]`` 2352 Normally, if QEMU is compiled with graphical window support, it 2353 displays output such as guest graphics, guest console, and the QEMU 2354 monitor in a window. With this option, you can have QEMU listen on 2355 VNC display display and redirect the VGA display over the VNC 2356 session. It is very useful to enable the usb tablet device when 2357 using this option (option ``-device usb-tablet``). When using the 2358 VNC display, you must use the ``-k`` parameter to set the keyboard 2359 layout if you are not using en-us. Valid syntax for the display is 2360 2361 ``to=L`` 2362 With this option, QEMU will try next available VNC displays, 2363 until the number L, if the origianlly defined "-vnc display" is 2364 not available, e.g. port 5900+display is already used by another 2365 application. By default, to=0. 2366 2367 ``host:d`` 2368 TCP connections will only be allowed from host on display d. By 2369 convention the TCP port is 5900+d. Optionally, host can be 2370 omitted in which case the server will accept connections from 2371 any host. 2372 2373 ``unix:path`` 2374 Connections will be allowed over UNIX domain sockets where path 2375 is the location of a unix socket to listen for connections on. 2376 2377 ``none`` 2378 VNC is initialized but not started. The monitor ``change`` 2379 command can be used to later start the VNC server. 2380 2381 Following the display value there may be one or more option flags 2382 separated by commas. Valid options are 2383 2384 ``reverse=on|off`` 2385 Connect to a listening VNC client via a "reverse" connection. 2386 The client is specified by the display. For reverse network 2387 connections (host:d,``reverse``), the d argument is a TCP port 2388 number, not a display number. 2389 2390 ``websocket=on|off`` 2391 Opens an additional TCP listening port dedicated to VNC 2392 Websocket connections. If a bare websocket option is given, the 2393 Websocket port is 5700+display. An alternative port can be 2394 specified with the syntax ``websocket``\ =port. 2395 2396 If host is specified connections will only be allowed from this 2397 host. It is possible to control the websocket listen address 2398 independently, using the syntax ``websocket``\ =host:port. 2399 2400 If no TLS credentials are provided, the websocket connection 2401 runs in unencrypted mode. If TLS credentials are provided, the 2402 websocket connection requires encrypted client connections. 2403 2404 ``password=on|off`` 2405 Require that password based authentication is used for client 2406 connections. 2407 2408 The password must be set separately using the ``set_password`` 2409 command in the :ref:`QEMU monitor`. The 2410 syntax to change your password is: 2411 ``set_password <protocol> <password>`` where <protocol> could be 2412 either "vnc" or "spice". 2413 2414 If you would like to change <protocol> password expiration, you 2415 should use ``expire_password <protocol> <expiration-time>`` 2416 where expiration time could be one of the following options: 2417 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2418 make password expire in 60 seconds, or 1335196800 to make 2419 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2420 this date and time). 2421 2422 You can also use keywords "now" or "never" for the expiration 2423 time to allow <protocol> password to expire immediately or never 2424 expire. 2425 2426 ``password-secret=<secret-id>`` 2427 Require that password based authentication is used for client 2428 connections, using the password provided by the ``secret`` 2429 object identified by ``secret-id``. 2430 2431 ``tls-creds=ID`` 2432 Provides the ID of a set of TLS credentials to use to secure the 2433 VNC server. They will apply to both the normal VNC server socket 2434 and the websocket socket (if enabled). Setting TLS credentials 2435 will cause the VNC server socket to enable the VeNCrypt auth 2436 mechanism. The credentials should have been previously created 2437 using the ``-object tls-creds`` argument. 2438 2439 ``tls-authz=ID`` 2440 Provides the ID of the QAuthZ authorization object against which 2441 the client's x509 distinguished name will validated. This object 2442 is only resolved at time of use, so can be deleted and recreated 2443 on the fly while the VNC server is active. If missing, it will 2444 default to denying access. 2445 2446 ``sasl=on|off`` 2447 Require that the client use SASL to authenticate with the VNC 2448 server. The exact choice of authentication method used is 2449 controlled from the system / user's SASL configuration file for 2450 the 'qemu' service. This is typically found in 2451 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2452 an environment variable SASL\_CONF\_PATH can be used to make it 2453 search alternate locations for the service config. While some 2454 SASL auth methods can also provide data encryption (eg GSSAPI), 2455 it is recommended that SASL always be combined with the 'tls' 2456 and 'x509' settings to enable use of SSL and server 2457 certificates. This ensures a data encryption preventing 2458 compromise of authentication credentials. See the 2459 :ref:`VNC security` section in the System Emulation Users Guide 2460 for details on using SASL authentication. 2461 2462 ``sasl-authz=ID`` 2463 Provides the ID of the QAuthZ authorization object against which 2464 the client's SASL username will validated. This object is only 2465 resolved at time of use, so can be deleted and recreated on the 2466 fly while the VNC server is active. If missing, it will default 2467 to denying access. 2468 2469 ``acl=on|off`` 2470 Legacy method for enabling authorization of clients against the 2471 x509 distinguished name and SASL username. It results in the 2472 creation of two ``authz-list`` objects with IDs of 2473 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2474 objects must be configured with the HMP ACL commands. 2475 2476 This option is deprecated and should no longer be used. The new 2477 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2478 2479 ``lossy=on|off`` 2480 Enable lossy compression methods (gradient, JPEG, ...). If this 2481 option is set, VNC client may receive lossy framebuffer updates 2482 depending on its encoding settings. Enabling this option can 2483 save a lot of bandwidth at the expense of quality. 2484 2485 ``non-adaptive=on|off`` 2486 Disable adaptive encodings. Adaptive encodings are enabled by 2487 default. An adaptive encoding will try to detect frequently 2488 updated screen regions, and send updates in these regions using 2489 a lossy encoding (like JPEG). This can be really helpful to save 2490 bandwidth when playing videos. Disabling adaptive encodings 2491 restores the original static behavior of encodings like Tight. 2492 2493 ``share=[allow-exclusive|force-shared|ignore]`` 2494 Set display sharing policy. 'allow-exclusive' allows clients to 2495 ask for exclusive access. As suggested by the rfb spec this is 2496 implemented by dropping other connections. Connecting multiple 2497 clients in parallel requires all clients asking for a shared 2498 session (vncviewer: -shared switch). This is the default. 2499 'force-shared' disables exclusive client access. Useful for 2500 shared desktop sessions, where you don't want someone forgetting 2501 specify -shared disconnect everybody else. 'ignore' completely 2502 ignores the shared flag and allows everybody connect 2503 unconditionally. Doesn't conform to the rfb spec but is 2504 traditional QEMU behavior. 2505 2506 ``key-delay-ms`` 2507 Set keyboard delay, for key down and key up events, in 2508 milliseconds. Default is 10. Keyboards are low-bandwidth 2509 devices, so this slowdown can help the device and guest to keep 2510 up and not lose events in case events are arriving in bulk. 2511 Possible causes for the latter are flaky network connections, or 2512 scripts for automated testing. 2513 2514 ``audiodev=audiodev`` 2515 Use the specified audiodev when the VNC client requests audio 2516 transmission. When not using an -audiodev argument, this option 2517 must be omitted, otherwise is must be present and specify a 2518 valid audiodev. 2519 2520 ``power-control=on|off`` 2521 Permit the remote client to issue shutdown, reboot or reset power 2522 control requests. 2523ERST 2524 2525ARCHHEADING(, QEMU_ARCH_I386) 2526 2527ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2528 2529DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2530 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2531 QEMU_ARCH_I386) 2532SRST 2533``-win2k-hack`` 2534 Use it when installing Windows 2000 to avoid a disk full bug. After 2535 Windows 2000 is installed, you no longer need this option (this 2536 option slows down the IDE transfers). 2537ERST 2538 2539DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2540 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2541 QEMU_ARCH_I386) 2542SRST 2543``-no-fd-bootchk`` 2544 Disable boot signature checking for floppy disks in BIOS. May be 2545 needed to boot from old floppy disks. 2546ERST 2547 2548DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2549 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2550SRST 2551``-no-acpi`` 2552 Disable ACPI (Advanced Configuration and Power Interface) support. 2553 Use it if your guest OS complains about ACPI problems (PC target 2554 machine only). 2555ERST 2556 2557DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2558 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2559SRST 2560``-no-hpet`` 2561 Disable HPET support. Deprecated, use '-machine hpet=off' instead. 2562ERST 2563 2564DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2565 "-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" 2566 " ACPI table description\n", QEMU_ARCH_I386) 2567SRST 2568``-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]...]`` 2569 Add ACPI table with specified header fields and context from 2570 specified files. For file=, take whole ACPI table from the specified 2571 files, including all ACPI headers (possible overridden by other 2572 options). For data=, only data portion of the table is used, all 2573 header information is specified in the command line. If a SLIC table 2574 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2575 fields will override the same in the RSDT and the FADT (a.k.a. 2576 FACP), in order to ensure the field matches required by the 2577 Microsoft SLIC spec and the ACPI spec. 2578ERST 2579 2580DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2581 "-smbios file=binary\n" 2582 " load SMBIOS entry from binary file\n" 2583 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2584 " [,uefi=on|off]\n" 2585 " specify SMBIOS type 0 fields\n" 2586 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2587 " [,uuid=uuid][,sku=str][,family=str]\n" 2588 " specify SMBIOS type 1 fields\n" 2589 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2590 " [,asset=str][,location=str]\n" 2591 " specify SMBIOS type 2 fields\n" 2592 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2593 " [,sku=str]\n" 2594 " specify SMBIOS type 3 fields\n" 2595 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2596 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2597 " [,processor-id=%d]\n" 2598 " specify SMBIOS type 4 fields\n" 2599 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2600 " specify SMBIOS type 8 fields\n" 2601 "-smbios type=11[,value=str][,path=filename]\n" 2602 " specify SMBIOS type 11 fields\n" 2603 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2604 " [,asset=str][,part=str][,speed=%d]\n" 2605 " specify SMBIOS type 17 fields\n" 2606 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2607 " specify SMBIOS type 41 fields\n", 2608 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2609SRST 2610``-smbios file=binary`` 2611 Load SMBIOS entry from binary file. 2612 2613``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2614 Specify SMBIOS type 0 fields 2615 2616``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2617 Specify SMBIOS type 1 fields 2618 2619``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2620 Specify SMBIOS type 2 fields 2621 2622``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2623 Specify SMBIOS type 3 fields 2624 2625``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2626 Specify SMBIOS type 4 fields 2627 2628``-smbios type=11[,value=str][,path=filename]`` 2629 Specify SMBIOS type 11 fields 2630 2631 This argument can be repeated multiple times, and values are added in the order they are parsed. 2632 Applications intending to use OEM strings data are encouraged to use their application name as 2633 a prefix for the value string. This facilitates passing information for multiple applications 2634 concurrently. 2635 2636 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2637 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2638 2639 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2640 the SMBIOS table in the order in which they appear. 2641 2642 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2643 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2644 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2645 data set, for example, by specifying the serial ID of a block device. 2646 2647 An example passing three strings is 2648 2649 .. parsed-literal:: 2650 2651 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2652 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2653 path=/some/file/with/oemstringsdata.txt 2654 2655 In the guest OS this is visible with the ``dmidecode`` command 2656 2657 .. parsed-literal:: 2658 2659 $ dmidecode -t 11 2660 Handle 0x0E00, DMI type 11, 5 bytes 2661 OEM Strings 2662 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2663 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2664 String 3: myapp:some extra data 2665 2666 2667``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2668 Specify SMBIOS type 17 fields 2669 2670``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2671 Specify SMBIOS type 41 fields 2672 2673 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2674 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2675 position on the PCI bus. 2676 2677 Here is an example of use: 2678 2679 .. parsed-literal:: 2680 2681 -netdev user,id=internet \\ 2682 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2683 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2684 2685 In the guest OS, the device should then appear as ``eno1``: 2686 2687 ..parsed-literal:: 2688 2689 $ ip -brief l 2690 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2691 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2692 2693 Currently, the PCI device has to be attached to the root bus. 2694 2695ERST 2696 2697DEFHEADING() 2698 2699DEFHEADING(Network options:) 2700 2701DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2702#ifdef CONFIG_SLIRP 2703 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2704 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2705 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2706 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2707 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2708#ifndef _WIN32 2709 "[,smb=dir[,smbserver=addr]]\n" 2710#endif 2711 " configure a user mode network backend with ID 'str',\n" 2712 " its DHCP server and optional services\n" 2713#endif 2714#ifdef _WIN32 2715 "-netdev tap,id=str,ifname=name\n" 2716 " configure a host TAP network backend with ID 'str'\n" 2717#else 2718 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2719 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2720 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2721 " [,poll-us=n]\n" 2722 " configure a host TAP network backend with ID 'str'\n" 2723 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2724 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2725 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2726 " to deconfigure it\n" 2727 " use '[down]script=no' to disable script execution\n" 2728 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2729 " configure it\n" 2730 " use 'fd=h' to connect to an already opened TAP interface\n" 2731 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2732 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2733 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2734 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2735 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2736 " use vhost=on to enable experimental in kernel accelerator\n" 2737 " (only has effect for virtio guests which use MSIX)\n" 2738 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2739 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2740 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2741 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2742 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2743 " spent on busy polling for vhost net\n" 2744 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2745 " configure a host TAP network backend with ID 'str' that is\n" 2746 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2747 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2748#endif 2749#ifdef __linux__ 2750 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2751 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2752 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2753 " [,rxcookie=rxcookie][,offset=offset]\n" 2754 " configure a network backend with ID 'str' connected to\n" 2755 " an Ethernet over L2TPv3 pseudowire.\n" 2756 " Linux kernel 3.3+ as well as most routers can talk\n" 2757 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2758 " VM to a router and even VM to Host. It is a nearly-universal\n" 2759 " standard (RFC3931). Note - this implementation uses static\n" 2760 " pre-configured tunnels (same as the Linux kernel).\n" 2761 " use 'src=' to specify source address\n" 2762 " use 'dst=' to specify destination address\n" 2763 " use 'udp=on' to specify udp encapsulation\n" 2764 " use 'srcport=' to specify source udp port\n" 2765 " use 'dstport=' to specify destination udp port\n" 2766 " use 'ipv6=on' to force v6\n" 2767 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2768 " well as a weak security measure\n" 2769 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2770 " use 'txcookie=0x012345678' to specify a txcookie\n" 2771 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2772 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2773 " use 'pincounter=on' to work around broken counter handling in peer\n" 2774 " use 'offset=X' to add an extra offset between header and data\n" 2775#endif 2776 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2777 " configure a network backend to connect to another network\n" 2778 " using a socket connection\n" 2779 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2780 " configure a network backend to connect to a multicast maddr and port\n" 2781 " use 'localaddr=addr' to specify the host address to send packets from\n" 2782 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2783 " configure a network backend to connect to another network\n" 2784 " using an UDP tunnel\n" 2785 "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]\n" 2786 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2787 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2788 " configure a network backend to connect to another network\n" 2789 " using a socket connection in stream mode.\n" 2790 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2791 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2792 " configure a network backend to connect to a multicast maddr and port\n" 2793 " use ``local.host=addr`` to specify the host address to send packets from\n" 2794 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2795 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2796 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2797 " configure a network backend to connect to another network\n" 2798 " using an UDP tunnel\n" 2799#ifdef CONFIG_VDE 2800 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2801 " configure a network backend to connect to port 'n' of a vde switch\n" 2802 " running on host and listening for incoming connections on 'socketpath'.\n" 2803 " Use group 'groupname' and mode 'octalmode' to change default\n" 2804 " ownership and permissions for communication port.\n" 2805#endif 2806#ifdef CONFIG_NETMAP 2807 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2808 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2809 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2810 " netmap device, defaults to '/dev/netmap')\n" 2811#endif 2812#ifdef CONFIG_POSIX 2813 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2814 " configure a vhost-user network, backed by a chardev 'dev'\n" 2815#endif 2816#ifdef __linux__ 2817 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2818 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2819 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2820 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2821#endif 2822#ifdef CONFIG_VMNET 2823 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2824 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2825 " configure a vmnet network backend in host mode with ID 'str',\n" 2826 " isolate this interface from others with 'isolated',\n" 2827 " configure the address range and choose a subnet mask,\n" 2828 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2829 " vmnet-host interfaces within this isolated network\n" 2830 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2831 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2832 " configure a vmnet network backend in shared mode with ID 'str',\n" 2833 " configure the address range and choose a subnet mask,\n" 2834 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2835 " isolate this interface from others with 'isolated'\n" 2836 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2837 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2838 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2839 " isolate this interface from others with 'isolated'\n" 2840#endif 2841 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2842 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2843DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2844 "-nic [tap|bridge|" 2845#ifdef CONFIG_SLIRP 2846 "user|" 2847#endif 2848#ifdef __linux__ 2849 "l2tpv3|" 2850#endif 2851#ifdef CONFIG_VDE 2852 "vde|" 2853#endif 2854#ifdef CONFIG_NETMAP 2855 "netmap|" 2856#endif 2857#ifdef CONFIG_POSIX 2858 "vhost-user|" 2859#endif 2860#ifdef CONFIG_VMNET 2861 "vmnet-host|vmnet-shared|vmnet-bridged|" 2862#endif 2863 "socket][,option][,...][mac=macaddr]\n" 2864 " initialize an on-board / default host NIC (using MAC address\n" 2865 " macaddr) and connect it to the given host network backend\n" 2866 "-nic none use it alone to have zero network devices (the default is to\n" 2867 " provided a 'user' network connection)\n", 2868 QEMU_ARCH_ALL) 2869DEF("net", HAS_ARG, QEMU_OPTION_net, 2870 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2871 " configure or create an on-board (or machine default) NIC and\n" 2872 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2873 "-net [" 2874#ifdef CONFIG_SLIRP 2875 "user|" 2876#endif 2877 "tap|" 2878 "bridge|" 2879#ifdef CONFIG_VDE 2880 "vde|" 2881#endif 2882#ifdef CONFIG_NETMAP 2883 "netmap|" 2884#endif 2885#ifdef CONFIG_VMNET 2886 "vmnet-host|vmnet-shared|vmnet-bridged|" 2887#endif 2888 "socket][,option][,option][,...]\n" 2889 " old way to initialize a host network interface\n" 2890 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2891SRST 2892``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2893 This option is a shortcut for configuring both the on-board 2894 (default) guest NIC hardware and the host network backend in one go. 2895 The host backend options are the same as with the corresponding 2896 ``-netdev`` options below. The guest NIC model can be set with 2897 ``model=modelname``. Use ``model=help`` to list the available device 2898 types. The hardware MAC address can be set with ``mac=macaddr``. 2899 2900 The following two example do exactly the same, to show how ``-nic`` 2901 can be used to shorten the command line length: 2902 2903 .. parsed-literal:: 2904 2905 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2906 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2907 2908``-nic none`` 2909 Indicate that no network devices should be configured. It is used to 2910 override the default configuration (default NIC with "user" host 2911 network backend) which is activated if no other networking options 2912 are provided. 2913 2914``-netdev user,id=id[,option][,option][,...]`` 2915 Configure user mode host network backend which requires no 2916 administrator privilege to run. Valid options are: 2917 2918 ``id=id`` 2919 Assign symbolic name for use in monitor commands. 2920 2921 ``ipv4=on|off and ipv6=on|off`` 2922 Specify that either IPv4 or IPv6 must be enabled. If neither is 2923 specified both protocols are enabled. 2924 2925 ``net=addr[/mask]`` 2926 Set IP network address the guest will see. Optionally specify 2927 the netmask, either in the form a.b.c.d or as number of valid 2928 top-most bits. Default is 10.0.2.0/24. 2929 2930 ``host=addr`` 2931 Specify the guest-visible address of the host. Default is the 2932 2nd IP in the guest network, i.e. x.x.x.2. 2933 2934 ``ipv6-net=addr[/int]`` 2935 Set IPv6 network address the guest will see (default is 2936 fec0::/64). The network prefix is given in the usual hexadecimal 2937 IPv6 address notation. The prefix size is optional, and is given 2938 as the number of valid top-most bits (default is 64). 2939 2940 ``ipv6-host=addr`` 2941 Specify the guest-visible IPv6 address of the host. Default is 2942 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2943 2944 ``restrict=on|off`` 2945 If this option is enabled, the guest will be isolated, i.e. it 2946 will not be able to contact the host and no guest IP packets 2947 will be routed over the host to the outside. This option does 2948 not affect any explicitly set forwarding rules. 2949 2950 ``hostname=name`` 2951 Specifies the client hostname reported by the built-in DHCP 2952 server. 2953 2954 ``dhcpstart=addr`` 2955 Specify the first of the 16 IPs the built-in DHCP server can 2956 assign. Default is the 15th to 31st IP in the guest network, 2957 i.e. x.x.x.15 to x.x.x.31. 2958 2959 ``dns=addr`` 2960 Specify the guest-visible address of the virtual nameserver. The 2961 address must be different from the host address. Default is the 2962 3rd IP in the guest network, i.e. x.x.x.3. 2963 2964 ``ipv6-dns=addr`` 2965 Specify the guest-visible address of the IPv6 virtual 2966 nameserver. The address must be different from the host address. 2967 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2968 2969 ``dnssearch=domain`` 2970 Provides an entry for the domain-search list sent by the 2971 built-in DHCP server. More than one domain suffix can be 2972 transmitted by specifying this option multiple times. If 2973 supported, this will cause the guest to automatically try to 2974 append the given domain suffix(es) in case a domain name can not 2975 be resolved. 2976 2977 Example: 2978 2979 .. parsed-literal:: 2980 2981 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2982 2983 ``domainname=domain`` 2984 Specifies the client domain name reported by the built-in DHCP 2985 server. 2986 2987 ``tftp=dir`` 2988 When using the user mode network stack, activate a built-in TFTP 2989 server. The files in dir will be exposed as the root of a TFTP 2990 server. The TFTP client on the guest must be configured in 2991 binary mode (use the command ``bin`` of the Unix TFTP client). 2992 2993 ``tftp-server-name=name`` 2994 In BOOTP reply, broadcast name as the "TFTP server name" 2995 (RFC2132 option 66). This can be used to advise the guest to 2996 load boot files or configurations from a different server than 2997 the host address. 2998 2999 ``bootfile=file`` 3000 When using the user mode network stack, broadcast file as the 3001 BOOTP filename. In conjunction with ``tftp``, this can be used 3002 to network boot a guest from a local directory. 3003 3004 Example (using pxelinux): 3005 3006 .. parsed-literal:: 3007 3008 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3009 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3010 3011 ``smb=dir[,smbserver=addr]`` 3012 When using the user mode network stack, activate a built-in SMB 3013 server so that Windows OSes can access to the host files in 3014 ``dir`` transparently. The IP address of the SMB server can be 3015 set to addr. By default the 4th IP in the guest network is used, 3016 i.e. x.x.x.4. 3017 3018 In the guest Windows OS, the line: 3019 3020 :: 3021 3022 10.0.2.4 smbserver 3023 3024 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3025 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3026 NT/2000). 3027 3028 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3029 3030 Note that a SAMBA server must be installed on the host OS. 3031 3032 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3033 Redirect incoming TCP or UDP connections to the host port 3034 hostport to the guest IP address guestaddr on guest port 3035 guestport. If guestaddr is not specified, its value is x.x.x.15 3036 (default first address given by the built-in DHCP server). By 3037 specifying hostaddr, the rule can be bound to a specific host 3038 interface. If no connection type is set, TCP is used. This 3039 option can be given multiple times. 3040 3041 For example, to redirect host X11 connection from screen 1 to 3042 guest screen 0, use the following: 3043 3044 .. parsed-literal:: 3045 3046 # on the host 3047 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3048 # this host xterm should open in the guest X11 server 3049 xterm -display :1 3050 3051 To redirect telnet connections from host port 5555 to telnet 3052 port on the guest, use the following: 3053 3054 .. parsed-literal:: 3055 3056 # on the host 3057 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3058 telnet localhost 5555 3059 3060 Then when you use on the host ``telnet localhost 5555``, you 3061 connect to the guest telnet server. 3062 3063 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3064 Forward guest TCP connections to the IP address server on port 3065 port to the character device dev or to a program executed by 3066 cmd:command which gets spawned for each connection. This option 3067 can be given multiple times. 3068 3069 You can either use a chardev directly and have that one used 3070 throughout QEMU's lifetime, like in the following example: 3071 3072 .. parsed-literal:: 3073 3074 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3075 # the guest accesses it 3076 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3077 3078 Or you can execute a command on every TCP connection established 3079 by the guest, so that QEMU behaves similar to an inetd process 3080 for that virtual server: 3081 3082 .. parsed-literal:: 3083 3084 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3085 # and connect the TCP stream to its stdin/stdout 3086 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3087 3088``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3089 Configure a host TAP network backend with ID id. 3090 3091 Use the network script file to configure it and the network script 3092 dfile to deconfigure it. If name is not provided, the OS 3093 automatically provides one. The default network configure script is 3094 ``/etc/qemu-ifup`` and the default network deconfigure script is 3095 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3096 disable script execution. 3097 3098 If running QEMU as an unprivileged user, use the network helper 3099 to configure the TAP interface and attach it to the bridge. 3100 The default network helper executable is 3101 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3102 ``br0``. 3103 3104 ``fd``\ =h can be used to specify the handle of an already opened 3105 host TAP interface. 3106 3107 Examples: 3108 3109 .. parsed-literal:: 3110 3111 #launch a QEMU instance with the default network script 3112 |qemu_system| linux.img -nic tap 3113 3114 .. parsed-literal:: 3115 3116 #launch a QEMU instance with two NICs, each one connected 3117 #to a TAP device 3118 |qemu_system| linux.img \\ 3119 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3120 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3121 3122 .. parsed-literal:: 3123 3124 #launch a QEMU instance with the default network helper to 3125 #connect a TAP device to bridge br0 3126 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3127 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3128 3129``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3130 Connect a host TAP network interface to a host bridge device. 3131 3132 Use the network helper helper to configure the TAP interface and 3133 attach it to the bridge. The default network helper executable is 3134 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3135 ``br0``. 3136 3137 Examples: 3138 3139 .. parsed-literal:: 3140 3141 #launch a QEMU instance with the default network helper to 3142 #connect a TAP device to bridge br0 3143 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3144 3145 .. parsed-literal:: 3146 3147 #launch a QEMU instance with the default network helper to 3148 #connect a TAP device to bridge qemubr0 3149 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3150 3151``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3152 This host network backend can be used to connect the guest's network 3153 to another QEMU virtual machine using a TCP socket connection. If 3154 ``listen`` is specified, QEMU waits for incoming connections on port 3155 (host is optional). ``connect`` is used to connect to another QEMU 3156 instance using the ``listen`` option. ``fd``\ =h specifies an 3157 already opened TCP socket. 3158 3159 Example: 3160 3161 .. parsed-literal:: 3162 3163 # launch a first QEMU instance 3164 |qemu_system| linux.img \\ 3165 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3166 -netdev socket,id=n1,listen=:1234 3167 # connect the network of this instance to the network of the first instance 3168 |qemu_system| linux.img \\ 3169 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3170 -netdev socket,id=n2,connect=127.0.0.1:1234 3171 3172``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3173 Configure a socket host network backend to share the guest's network 3174 traffic with another QEMU virtual machines using a UDP multicast 3175 socket, effectively making a bus for every QEMU with same multicast 3176 address maddr and port. NOTES: 3177 3178 1. Several QEMU can be running on different hosts and share same bus 3179 (assuming correct multicast setup for these hosts). 3180 3181 2. mcast support is compatible with User Mode Linux (argument 3182 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3183 3184 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3185 3186 Example: 3187 3188 .. parsed-literal:: 3189 3190 # launch one QEMU instance 3191 |qemu_system| linux.img \\ 3192 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3193 -netdev socket,id=n1,mcast=230.0.0.1:1234 3194 # launch another QEMU instance on same "bus" 3195 |qemu_system| linux.img \\ 3196 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3197 -netdev socket,id=n2,mcast=230.0.0.1:1234 3198 # launch yet another QEMU instance on same "bus" 3199 |qemu_system| linux.img \\ 3200 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3201 -netdev socket,id=n3,mcast=230.0.0.1:1234 3202 3203 Example (User Mode Linux compat.): 3204 3205 .. parsed-literal:: 3206 3207 # launch QEMU instance (note mcast address selected is UML's default) 3208 |qemu_system| linux.img \\ 3209 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3210 -netdev socket,id=n1,mcast=239.192.168.1:1102 3211 # launch UML 3212 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3213 3214 Example (send packets from host's 1.2.3.4): 3215 3216 .. parsed-literal:: 3217 3218 |qemu_system| linux.img \\ 3219 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3220 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3221 3222``-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]`` 3223 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3224 is a popular protocol to transport Ethernet (and other Layer 2) data 3225 frames between two systems. It is present in routers, firewalls and 3226 the Linux kernel (from version 3.3 onwards). 3227 3228 This transport allows a VM to communicate to another VM, router or 3229 firewall directly. 3230 3231 ``src=srcaddr`` 3232 source address (mandatory) 3233 3234 ``dst=dstaddr`` 3235 destination address (mandatory) 3236 3237 ``udp`` 3238 select udp encapsulation (default is ip). 3239 3240 ``srcport=srcport`` 3241 source udp port. 3242 3243 ``dstport=dstport`` 3244 destination udp port. 3245 3246 ``ipv6`` 3247 force v6, otherwise defaults to v4. 3248 3249 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3250 Cookies are a weak form of security in the l2tpv3 specification. 3251 Their function is mostly to prevent misconfiguration. By default 3252 they are 32 bit. 3253 3254 ``cookie64`` 3255 Set cookie size to 64 bit instead of the default 32 3256 3257 ``counter=off`` 3258 Force a 'cut-down' L2TPv3 with no counter as in 3259 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3260 3261 ``pincounter=on`` 3262 Work around broken counter handling in peer. This may also help 3263 on networks which have packet reorder. 3264 3265 ``offset=offset`` 3266 Add an extra offset between header and data 3267 3268 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3269 the bridge br-lan on the remote Linux host 1.2.3.4: 3270 3271 .. parsed-literal:: 3272 3273 # Setup tunnel on linux host using raw ip as encapsulation 3274 # on 1.2.3.4 3275 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3276 encap udp udp_sport 16384 udp_dport 16384 3277 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3278 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3279 ifconfig vmtunnel0 mtu 1500 3280 ifconfig vmtunnel0 up 3281 brctl addif br-lan vmtunnel0 3282 3283 3284 # on 4.3.2.1 3285 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3286 3287 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3288 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3289 3290``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3291 Configure VDE backend to connect to PORT n of a vde switch running 3292 on host and listening for incoming connections on socketpath. Use 3293 GROUP groupname and MODE octalmode to change default ownership and 3294 permissions for communication port. This option is only available if 3295 QEMU has been compiled with vde support enabled. 3296 3297 Example: 3298 3299 .. parsed-literal:: 3300 3301 # launch vde switch 3302 vde_switch -F -sock /tmp/myswitch 3303 # launch QEMU instance 3304 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3305 3306``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3307 Establish a vhost-user netdev, backed by a chardev id. The chardev 3308 should be a unix domain socket backed one. The vhost-user uses a 3309 specifically defined protocol to pass vhost ioctl replacement 3310 messages to an application on the other end of the socket. On 3311 non-MSIX guests, the feature can be forced with vhostforce. Use 3312 'queues=n' to specify the number of queues to be created for 3313 multiqueue vhost-user. 3314 3315 Example: 3316 3317 :: 3318 3319 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3320 -numa node,memdev=mem \ 3321 -chardev socket,id=chr0,path=/path/to/socket \ 3322 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3323 -device virtio-net-pci,netdev=net0 3324 3325``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3326 Establish a vhost-vdpa netdev. 3327 3328 vDPA device is a device that uses a datapath which complies with 3329 the virtio specifications with a vendor specific control path. 3330 vDPA devices can be both physically located on the hardware or 3331 emulated by software. 3332 3333``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3334 Create a hub port on the emulated hub with ID hubid. 3335 3336 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3337 instead of a single netdev. Alternatively, you can also connect the 3338 hubport to another netdev with ID nd by using the ``netdev=nd`` 3339 option. 3340 3341``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3342 Legacy option to configure or create an on-board (or machine 3343 default) Network Interface Card(NIC) and connect it either to the 3344 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3345 If model is omitted, then the default NIC model associated with the 3346 machine type is used. Note that the default NIC model may change in 3347 future QEMU releases, so it is highly recommended to always specify 3348 a model. Optionally, the MAC address can be changed to mac, the 3349 device address set to addr (PCI cards only), and a name can be 3350 assigned for use in monitor commands. Optionally, for PCI cards, you 3351 can specify the number v of MSI-X vectors that the card should have; 3352 this option currently only affects virtio cards; set v = 0 to 3353 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3354 created. QEMU can emulate several different models of network card. 3355 Use ``-net nic,model=help`` for a list of available devices for your 3356 target. 3357 3358``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3359 Configure a host network backend (with the options corresponding to 3360 the same ``-netdev`` option) and connect it to the emulated hub 0 3361 (the default hub). Use name to specify the name of the hub port. 3362ERST 3363 3364DEFHEADING() 3365 3366DEFHEADING(Character device options:) 3367 3368DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3369 "-chardev help\n" 3370 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3371 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3372 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3373 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3374 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3375 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3376 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3377 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3378 " [,logfile=PATH][,logappend=on|off]\n" 3379 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3380 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3381 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3382 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3383 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3384 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3385#ifdef _WIN32 3386 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3387 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3388#else 3389 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3390 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3391#endif 3392#ifdef CONFIG_BRLAPI 3393 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3394#endif 3395#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3396 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3397 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3398#endif 3399#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3400 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3401#endif 3402#if defined(CONFIG_SPICE) 3403 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3404 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3405#endif 3406 , QEMU_ARCH_ALL 3407) 3408 3409SRST 3410The general form of a character device option is: 3411 3412``-chardev backend,id=id[,mux=on|off][,options]`` 3413 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3414 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3415 ``pty``, ``stdio``, ``braille``, ``parallel``, 3416 ``spicevmc``, ``spiceport``. The specific backend will determine the 3417 applicable options. 3418 3419 Use ``-chardev help`` to print all available chardev backend types. 3420 3421 All devices must have an id, which can be any string up to 127 3422 characters long. It is used to uniquely identify this device in 3423 other command line directives. 3424 3425 A character device may be used in multiplexing mode by multiple 3426 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3427 a "1:N" device, and here the "1" end is your specified chardev 3428 backend, and the "N" end is the various parts of QEMU that can talk 3429 to a chardev. If you create a chardev with ``id=myid`` and 3430 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3431 and you can then configure multiple front ends to use that chardev 3432 ID for their input/output. Up to four different front ends can be 3433 connected to a single multiplexed chardev. (Without multiplexing 3434 enabled, a chardev can only be used by a single front end.) For 3435 instance you could use this to allow a single stdio chardev to be 3436 used by two serial ports and the QEMU monitor: 3437 3438 :: 3439 3440 -chardev stdio,mux=on,id=char0 \ 3441 -mon chardev=char0,mode=readline \ 3442 -serial chardev:char0 \ 3443 -serial chardev:char0 3444 3445 You can have more than one multiplexer in a system configuration; 3446 for instance you could have a TCP port multiplexed between UART 0 3447 and UART 1, and stdio multiplexed between the QEMU monitor and a 3448 parallel port: 3449 3450 :: 3451 3452 -chardev stdio,mux=on,id=char0 \ 3453 -mon chardev=char0,mode=readline \ 3454 -parallel chardev:char0 \ 3455 -chardev tcp,...,mux=on,id=char1 \ 3456 -serial chardev:char1 \ 3457 -serial chardev:char1 3458 3459 When you're using a multiplexed character device, some escape 3460 sequences are interpreted in the input. See the chapter about 3461 :ref:`keys in the character backend multiplexer` in the 3462 System Emulation Users Guide for more details. 3463 3464 Note that some other command line options may implicitly create 3465 multiplexed character backends; for instance ``-serial mon:stdio`` 3466 creates a multiplexed stdio backend connected to the serial port and 3467 the QEMU monitor, and ``-nographic`` also multiplexes the console 3468 and the monitor to stdio. 3469 3470 There is currently no support for multiplexing in the other 3471 direction (where a single QEMU front end takes input and output from 3472 multiple chardevs). 3473 3474 Every backend supports the ``logfile`` option, which supplies the 3475 path to a file to record all data transmitted via the backend. The 3476 ``logappend`` option controls whether the log file will be truncated 3477 or appended to when opened. 3478 3479The available backends are: 3480 3481``-chardev null,id=id`` 3482 A void device. This device will not emit any data, and will drop any 3483 data it receives. The null backend does not take any options. 3484 3485``-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]`` 3486 Create a two-way stream socket, which can be either a TCP or a unix 3487 socket. A unix socket will be created if ``path`` is specified. 3488 Behaviour is undefined if TCP options are specified for a unix 3489 socket. 3490 3491 ``server=on|off`` specifies that the socket shall be a listening socket. 3492 3493 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3494 to connect to a listening socket. 3495 3496 ``telnet=on|off`` specifies that traffic on the socket should interpret 3497 telnet escape sequences. 3498 3499 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3500 communication. 3501 3502 ``reconnect`` sets the timeout for reconnecting on non-server 3503 sockets when the remote end goes away. qemu will delay this many 3504 seconds and then attempt to reconnect. Zero disables reconnecting, 3505 and is the default. 3506 3507 ``tls-creds`` requests enablement of the TLS protocol for 3508 encryption, and specifies the id of the TLS credentials to use for 3509 the handshake. The credentials must be previously created with the 3510 ``-object tls-creds`` argument. 3511 3512 ``tls-auth`` provides the ID of the QAuthZ authorization object 3513 against which the client's x509 distinguished name will be 3514 validated. This object is only resolved at time of use, so can be 3515 deleted and recreated on the fly while the chardev server is active. 3516 If missing, it will default to denying access. 3517 3518 TCP and unix socket options are given below: 3519 3520 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3521 ``host`` for a listening socket specifies the local address to 3522 be bound. For a connecting socket species the remote host to 3523 connect to. ``host`` is optional for listening sockets. If not 3524 specified it defaults to ``0.0.0.0``. 3525 3526 ``port`` for a listening socket specifies the local port to be 3527 bound. For a connecting socket specifies the port on the remote 3528 host to connect to. ``port`` can be given as either a port 3529 number or a service name. ``port`` is required. 3530 3531 ``to`` is only relevant to listening sockets. If it is 3532 specified, and ``port`` cannot be bound, QEMU will attempt to 3533 bind to subsequent ports up to and including ``to`` until it 3534 succeeds. ``to`` must be specified as a port number. 3535 3536 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3537 or IPv6 must be used. If neither is specified the socket may 3538 use either protocol. 3539 3540 ``nodelay=on|off`` disables the Nagle algorithm. 3541 3542 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3543 ``path`` specifies the local path of the unix socket. ``path`` 3544 is required. 3545 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3546 rather than the filesystem. Optional, defaults to false. 3547 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3548 rather than the full sun_path length. Optional, defaults to true. 3549 3550``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3551 Sends all traffic from the guest to a remote host over UDP. 3552 3553 ``host`` specifies the remote host to connect to. If not specified 3554 it defaults to ``localhost``. 3555 3556 ``port`` specifies the port on the remote host to connect to. 3557 ``port`` is required. 3558 3559 ``localaddr`` specifies the local address to bind to. If not 3560 specified it defaults to ``0.0.0.0``. 3561 3562 ``localport`` specifies the local port to bind to. If not specified 3563 any available local port will be used. 3564 3565 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3566 If neither is specified the device may use either protocol. 3567 3568``-chardev msmouse,id=id`` 3569 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3570 does not take any options. 3571 3572``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3573 Connect to a QEMU text console. ``vc`` may optionally be given a 3574 specific size. 3575 3576 ``width`` and ``height`` specify the width and height respectively 3577 of the console, in pixels. 3578 3579 ``cols`` and ``rows`` specify that the console be sized to fit a 3580 text console with the given dimensions. 3581 3582``-chardev ringbuf,id=id[,size=size]`` 3583 Create a ring buffer with fixed size ``size``. size must be a power 3584 of two and defaults to ``64K``. 3585 3586``-chardev file,id=id,path=path[,input-path=input-path]`` 3587 Log all traffic received from the guest to a file. 3588 3589 ``path`` specifies the path of the file to be opened. This file will 3590 be created if it does not already exist, and overwritten if it does. 3591 ``path`` is required. 3592 3593 If ``input-path`` is specified, this is the path of a second file 3594 which will be used for input. If ``input-path`` is not specified, 3595 no input will be available from the chardev. 3596 3597 Note that ``input-path`` is not supported on Windows hosts. 3598 3599``-chardev pipe,id=id,path=path`` 3600 Create a two-way connection to the guest. The behaviour differs 3601 slightly between Windows hosts and other hosts: 3602 3603 On Windows, a single duplex pipe will be created at 3604 ``\\.pipe\path``. 3605 3606 On other hosts, 2 pipes will be created called ``path.in`` and 3607 ``path.out``. Data written to ``path.in`` will be received by the 3608 guest. Data written by the guest can be read from ``path.out``. QEMU 3609 will not create these fifos, and requires them to be present. 3610 3611 ``path`` forms part of the pipe path as described above. ``path`` is 3612 required. 3613 3614``-chardev console,id=id`` 3615 Send traffic from the guest to QEMU's standard output. ``console`` 3616 does not take any options. 3617 3618 ``console`` is only available on Windows hosts. 3619 3620``-chardev serial,id=id,path=path`` 3621 Send traffic from the guest to a serial device on the host. 3622 3623 On Unix hosts serial will actually accept any tty device, not only 3624 serial lines. 3625 3626 ``path`` specifies the name of the serial device to open. 3627 3628``-chardev pty,id=id`` 3629 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3630 does not take any options. 3631 3632 ``pty`` is not available on Windows hosts. 3633 3634``-chardev stdio,id=id[,signal=on|off]`` 3635 Connect to standard input and standard output of the QEMU process. 3636 3637 ``signal`` controls if signals are enabled on the terminal, that 3638 includes exiting QEMU with the key sequence Control-c. This option 3639 is enabled by default, use ``signal=off`` to disable it. 3640 3641``-chardev braille,id=id`` 3642 Connect to a local BrlAPI server. ``braille`` does not take any 3643 options. 3644 3645``-chardev parallel,id=id,path=path`` 3646 \ 3647 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3648 hosts. 3649 3650 Connect to a local parallel port. 3651 3652 ``path`` specifies the path to the parallel port device. ``path`` is 3653 required. 3654 3655``-chardev spicevmc,id=id,debug=debug,name=name`` 3656 ``spicevmc`` is only available when spice support is built in. 3657 3658 ``debug`` debug level for spicevmc 3659 3660 ``name`` name of spice channel to connect to 3661 3662 Connect to a spice virtual machine channel, such as vdiport. 3663 3664``-chardev spiceport,id=id,debug=debug,name=name`` 3665 ``spiceport`` is only available when spice support is built in. 3666 3667 ``debug`` debug level for spicevmc 3668 3669 ``name`` name of spice port to connect to 3670 3671 Connect to a spice port, allowing a Spice client to handle the 3672 traffic identified by a name (preferably a fqdn). 3673ERST 3674 3675DEFHEADING() 3676 3677#ifdef CONFIG_TPM 3678DEFHEADING(TPM device options:) 3679 3680DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3681 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3682 " use path to provide path to a character device; default is /dev/tpm0\n" 3683 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3684 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3685 "-tpmdev emulator,id=id,chardev=dev\n" 3686 " configure the TPM device using chardev backend\n", 3687 QEMU_ARCH_ALL) 3688SRST 3689The general form of a TPM device option is: 3690 3691``-tpmdev backend,id=id[,options]`` 3692 The specific backend type will determine the applicable options. The 3693 ``-tpmdev`` option creates the TPM backend and requires a 3694 ``-device`` option that specifies the TPM frontend interface model. 3695 3696 Use ``-tpmdev help`` to print all available TPM backend types. 3697 3698The available backends are: 3699 3700``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3701 (Linux-host only) Enable access to the host's TPM using the 3702 passthrough driver. 3703 3704 ``path`` specifies the path to the host's TPM device, i.e., on a 3705 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3706 default ``/dev/tpm0`` is used. 3707 3708 ``cancel-path`` specifies the path to the host TPM device's sysfs 3709 entry allowing for cancellation of an ongoing TPM command. 3710 ``cancel-path`` is optional and by default QEMU will search for the 3711 sysfs entry to use. 3712 3713 Some notes about using the host's TPM with the passthrough driver: 3714 3715 The TPM device accessed by the passthrough driver must not be used 3716 by any other application on the host. 3717 3718 Since the host's firmware (BIOS/UEFI) has already initialized the 3719 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3720 the TPM again and may therefore not show a TPM-specific menu that 3721 would otherwise allow the user to configure the TPM, e.g., allow the 3722 user to enable/disable or activate/deactivate the TPM. Further, if 3723 TPM ownership is released from within a VM then the host's TPM will 3724 get disabled and deactivated. To enable and activate the TPM again 3725 afterwards, the host has to be rebooted and the user is required to 3726 enter the firmware's menu to enable and activate the TPM. If the TPM 3727 is left disabled and/or deactivated most TPM commands will fail. 3728 3729 To create a passthrough TPM use the following two options: 3730 3731 :: 3732 3733 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3734 3735 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3736 ``tpmdev=tpm0`` in the device option. 3737 3738``-tpmdev emulator,id=id,chardev=dev`` 3739 (Linux-host only) Enable access to a TPM emulator using Unix domain 3740 socket based chardev backend. 3741 3742 ``chardev`` specifies the unique ID of a character device backend 3743 that provides connection to the software TPM server. 3744 3745 To create a TPM emulator backend device with chardev socket backend: 3746 3747 :: 3748 3749 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3750ERST 3751 3752DEFHEADING() 3753 3754#endif 3755 3756DEFHEADING(Boot Image or Kernel specific:) 3757SRST 3758There are broadly 4 ways you can boot a system with QEMU. 3759 3760 - specify a firmware and let it control finding a kernel 3761 - specify a firmware and pass a hint to the kernel to boot 3762 - direct kernel image boot 3763 - manually load files into the guest's address space 3764 3765The third method is useful for quickly testing kernels but as there is 3766no firmware to pass configuration information to the kernel the 3767hardware must either be probeable, the kernel built for the exact 3768configuration or passed some configuration data (e.g. a DTB blob) 3769which tells the kernel what drivers it needs. This exact details are 3770often hardware specific. 3771 3772The final method is the most generic way of loading images into the 3773guest address space and used mostly for ``bare metal`` type 3774development where the reset vectors of the processor are taken into 3775account. 3776 3777ERST 3778 3779SRST 3780 3781For x86 machines and some other architectures ``-bios`` will generally 3782do the right thing with whatever it is given. For other machines the 3783more strict ``-pflash`` option needs an image that is sized for the 3784flash device for the given machine type. 3785 3786Please see the :ref:`system-targets-ref` section of the manual for 3787more detailed documentation. 3788 3789ERST 3790 3791DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3792 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3793SRST 3794``-bios file`` 3795 Set the filename for the BIOS. 3796ERST 3797 3798DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3799 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3800SRST 3801``-pflash file`` 3802 Use file as a parallel flash image. 3803ERST 3804 3805SRST 3806 3807The kernel options were designed to work with Linux kernels although 3808other things (like hypervisors) can be packaged up as a kernel 3809executable image. The exact format of a executable image is usually 3810architecture specific. 3811 3812The way in which the kernel is started (what address it is loaded at, 3813what if any information is passed to it via CPU registers, the state 3814of the hardware when it is started, and so on) is also architecture 3815specific. Typically it follows the specification laid down by the 3816Linux kernel for how kernels for that architecture must be started. 3817 3818ERST 3819 3820DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3821 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3822SRST 3823``-kernel bzImage`` 3824 Use bzImage as kernel image. The kernel can be either a Linux kernel 3825 or in multiboot format. 3826ERST 3827 3828DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3829 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3830SRST 3831``-append cmdline`` 3832 Use cmdline as kernel command line 3833ERST 3834 3835DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3836 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3837SRST 3838``-initrd file`` 3839 Use file as initial ram disk. 3840 3841``-initrd "file1 arg=foo,file2"`` 3842 This syntax is only available with multiboot. 3843 3844 Use file1 and file2 as modules and pass arg=foo as parameter to the 3845 first module. 3846ERST 3847 3848DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3849 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3850SRST 3851``-dtb file`` 3852 Use file as a device tree binary (dtb) image and pass it to the 3853 kernel on boot. 3854ERST 3855 3856SRST 3857 3858Finally you can also manually load images directly into the address 3859space of the guest. This is most useful for developers who already 3860know the layout of their guest and take care to ensure something sane 3861will happen when the reset vector executes. 3862 3863The generic loader can be invoked by using the loader device: 3864 3865``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3866 3867there is also the guest loader which operates in a similar way but 3868tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3869the guest image is: 3870 3871``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3872 3873ERST 3874 3875DEFHEADING() 3876 3877DEFHEADING(Debug/Expert options:) 3878 3879DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3880 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3881 " Policy for handling deprecated management interfaces\n" 3882 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3883 " Policy for handling unstable management interfaces\n", 3884 QEMU_ARCH_ALL) 3885SRST 3886``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3887 Set policy for handling deprecated management interfaces (experimental): 3888 3889 ``deprecated-input=accept`` (default) 3890 Accept deprecated commands and arguments 3891 ``deprecated-input=reject`` 3892 Reject deprecated commands and arguments 3893 ``deprecated-input=crash`` 3894 Crash on deprecated commands and arguments 3895 ``deprecated-output=accept`` (default) 3896 Emit deprecated command results and events 3897 ``deprecated-output=hide`` 3898 Suppress deprecated command results and events 3899 3900 Limitation: covers only syntactic aspects of QMP. 3901 3902``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3903 Set policy for handling unstable management interfaces (experimental): 3904 3905 ``unstable-input=accept`` (default) 3906 Accept unstable commands and arguments 3907 ``unstable-input=reject`` 3908 Reject unstable commands and arguments 3909 ``unstable-input=crash`` 3910 Crash on unstable commands and arguments 3911 ``unstable-output=accept`` (default) 3912 Emit unstable command results and events 3913 ``unstable-output=hide`` 3914 Suppress unstable command results and events 3915 3916 Limitation: covers only syntactic aspects of QMP. 3917ERST 3918 3919DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3920 "-fw_cfg [name=]<name>,file=<file>\n" 3921 " add named fw_cfg entry with contents from file\n" 3922 "-fw_cfg [name=]<name>,string=<str>\n" 3923 " add named fw_cfg entry with contents from string\n", 3924 QEMU_ARCH_ALL) 3925SRST 3926``-fw_cfg [name=]name,file=file`` 3927 Add named fw\_cfg entry with contents from file file. 3928 3929``-fw_cfg [name=]name,string=str`` 3930 Add named fw\_cfg entry with contents from string str. 3931 3932 The terminating NUL character of the contents of str will not be 3933 included as part of the fw\_cfg item data. To insert contents with 3934 embedded NUL characters, you have to use the file parameter. 3935 3936 The fw\_cfg entries are passed by QEMU through to the guest. 3937 3938 Example: 3939 3940 :: 3941 3942 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3943 3944 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3945 from ./my\_blob.bin. 3946ERST 3947 3948DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3949 "-serial dev redirect the serial port to char device 'dev'\n", 3950 QEMU_ARCH_ALL) 3951SRST 3952``-serial dev`` 3953 Redirect the virtual serial port to host character device dev. The 3954 default device is ``vc`` in graphical mode and ``stdio`` in non 3955 graphical mode. 3956 3957 This option can be used several times to simulate up to 4 serial 3958 ports. 3959 3960 Use ``-serial none`` to disable all serial ports. 3961 3962 Available character devices are: 3963 3964 ``vc[:WxH]`` 3965 Virtual console. Optionally, a width and height can be given in 3966 pixel with 3967 3968 :: 3969 3970 vc:800x600 3971 3972 It is also possible to specify width or height in characters: 3973 3974 :: 3975 3976 vc:80Cx24C 3977 3978 ``pty`` 3979 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3980 3981 ``none`` 3982 No device is allocated. 3983 3984 ``null`` 3985 void device 3986 3987 ``chardev:id`` 3988 Use a named character device defined with the ``-chardev`` 3989 option. 3990 3991 ``/dev/XXX`` 3992 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3993 port parameters are set according to the emulated ones. 3994 3995 ``/dev/parportN`` 3996 [Linux only, parallel port only] Use host parallel port N. 3997 Currently SPP and EPP parallel port features can be used. 3998 3999 ``file:filename`` 4000 Write output to filename. No character can be read. 4001 4002 ``stdio`` 4003 [Unix only] standard input/output 4004 4005 ``pipe:filename`` 4006 name pipe filename 4007 4008 ``COMn`` 4009 [Windows only] Use host serial port n 4010 4011 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4012 This implements UDP Net Console. When remote\_host or src\_ip 4013 are not specified they default to ``0.0.0.0``. When not using a 4014 specified src\_port a random port is automatically chosen. 4015 4016 If you just want a simple readonly console you can use 4017 ``netcat`` or ``nc``, by starting QEMU with: 4018 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4019 QEMU writes something to that port it will appear in the 4020 netconsole session. 4021 4022 If you plan to send characters back via netconsole or you want 4023 to stop and start QEMU a lot of times, you should have QEMU use 4024 the same source port each time by using something like ``-serial 4025 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4026 version of netcat which can listen to a TCP port and send and 4027 receive characters via udp. If you have a patched version of 4028 netcat which activates telnet remote echo and single char 4029 transfer, then you can use the following options to set up a 4030 netcat redirector to allow telnet on port 5555 to access the 4031 QEMU port. 4032 4033 ``QEMU Options:`` 4034 -serial udp::4555@:4556 4035 4036 ``netcat options:`` 4037 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4038 4039 ``telnet options:`` 4040 localhost 5555 4041 4042 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4043 The TCP Net Console has two modes of operation. It can send the 4044 serial I/O to a location or wait for a connection from a 4045 location. By default the TCP Net Console is sent to host at the 4046 port. If you use the ``server=on`` option QEMU will wait for a client 4047 socket application to connect to the port before continuing, 4048 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4049 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4050 option only applies if ``server=no`` is set, if the connection goes 4051 down it will attempt to reconnect at the given interval. If host 4052 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4053 time is accepted. You can use ``telnet=on`` to connect to the 4054 corresponding character device. 4055 4056 ``Example to send tcp console to 192.168.0.2 port 4444`` 4057 -serial tcp:192.168.0.2:4444 4058 4059 ``Example to listen and wait on port 4444 for connection`` 4060 -serial tcp::4444,server=on 4061 4062 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4063 -serial tcp:192.168.0.100:4444,server=on,wait=off 4064 4065 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4066 The telnet protocol is used instead of raw tcp sockets. The 4067 options work the same as if you had specified ``-serial tcp``. 4068 The difference is that the port acts like a telnet server or 4069 client using telnet option negotiation. This will also allow you 4070 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4071 supports sending the break sequence. Typically in unix telnet 4072 you do it with Control-] and then type "send break" followed by 4073 pressing the enter key. 4074 4075 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4076 The WebSocket protocol is used instead of raw tcp socket. The 4077 port acts as a WebSocket server. Client mode is not supported. 4078 4079 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4080 A unix domain socket is used instead of a tcp socket. The option 4081 works the same as if you had specified ``-serial tcp`` except 4082 the unix domain socket path is used for connections. 4083 4084 ``mon:dev_string`` 4085 This is a special option to allow the monitor to be multiplexed 4086 onto another serial port. The monitor is accessed with key 4087 sequence of Control-a and then pressing c. dev\_string should be 4088 any one of the serial devices specified above. An example to 4089 multiplex the monitor onto a telnet server listening on port 4090 4444 would be: 4091 4092 ``-serial mon:telnet::4444,server=on,wait=off`` 4093 4094 When the monitor is multiplexed to stdio in this way, Ctrl+C 4095 will not terminate QEMU any more but will be passed to the guest 4096 instead. 4097 4098 ``braille`` 4099 Braille device. This will use BrlAPI to display the braille 4100 output on a real or fake device. 4101 4102 ``msmouse`` 4103 Three button serial mouse. Configure the guest to use Microsoft 4104 protocol. 4105ERST 4106 4107DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4108 "-parallel dev redirect the parallel port to char device 'dev'\n", 4109 QEMU_ARCH_ALL) 4110SRST 4111``-parallel dev`` 4112 Redirect the virtual parallel port to host device dev (same devices 4113 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4114 to use hardware devices connected on the corresponding host parallel 4115 port. 4116 4117 This option can be used several times to simulate up to 3 parallel 4118 ports. 4119 4120 Use ``-parallel none`` to disable all parallel ports. 4121ERST 4122 4123DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4124 "-monitor dev redirect the monitor to char device 'dev'\n", 4125 QEMU_ARCH_ALL) 4126SRST 4127``-monitor dev`` 4128 Redirect the monitor to host device dev (same devices as the serial 4129 port). The default device is ``vc`` in graphical mode and ``stdio`` 4130 in non graphical mode. Use ``-monitor none`` to disable the default 4131 monitor. 4132ERST 4133DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4134 "-qmp dev like -monitor but opens in 'control' mode\n", 4135 QEMU_ARCH_ALL) 4136SRST 4137``-qmp dev`` 4138 Like -monitor but opens in 'control' mode. 4139ERST 4140DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4141 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4142 QEMU_ARCH_ALL) 4143SRST 4144``-qmp-pretty dev`` 4145 Like -qmp but uses pretty JSON formatting. 4146ERST 4147 4148DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4149 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4150SRST 4151``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4152 Setup monitor on chardev name. ``mode=control`` configures 4153 a QMP monitor (a JSON RPC-style protocol) and it is not the 4154 same as HMP, the human monitor that has a "(qemu)" prompt. 4155 ``pretty`` is only valid when ``mode=control``, 4156 turning on JSON pretty printing to ease 4157 human reading and debugging. 4158ERST 4159 4160DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4161 "-debugcon dev redirect the debug console to char device 'dev'\n", 4162 QEMU_ARCH_ALL) 4163SRST 4164``-debugcon dev`` 4165 Redirect the debug console to host device dev (same devices as the 4166 serial port). The debug console is an I/O port which is typically 4167 port 0xe9; writing to that I/O port sends output to this device. The 4168 default device is ``vc`` in graphical mode and ``stdio`` in non 4169 graphical mode. 4170ERST 4171 4172DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4173 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4174SRST 4175``-pidfile file`` 4176 Store the QEMU process PID in file. It is useful if you launch QEMU 4177 from a script. 4178ERST 4179 4180DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4181 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4182SRST 4183``-singlestep`` 4184 Run the emulation in single step mode. 4185ERST 4186 4187DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4188 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4189 QEMU_ARCH_ALL) 4190SRST 4191``--preconfig`` 4192 Pause QEMU for interactive configuration before the machine is 4193 created, which allows querying and configuring properties that will 4194 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4195 exit the preconfig state and move to the next state (i.e. run guest 4196 if -S isn't used or pause the second time if -S is used). This 4197 option is experimental. 4198ERST 4199 4200DEF("S", 0, QEMU_OPTION_S, \ 4201 "-S freeze CPU at startup (use 'c' to start execution)\n", 4202 QEMU_ARCH_ALL) 4203SRST 4204``-S`` 4205 Do not start CPU at startup (you must type 'c' in the monitor). 4206ERST 4207 4208DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4209 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4210 " run qemu with overcommit hints\n" 4211 " mem-lock=on|off controls memory lock support (default: off)\n" 4212 " cpu-pm=on|off controls cpu power management (default: off)\n", 4213 QEMU_ARCH_ALL) 4214SRST 4215``-overcommit mem-lock=on|off`` 4216 \ 4217``-overcommit cpu-pm=on|off`` 4218 Run qemu with hints about host resource overcommit. The default is 4219 to assume that host overcommits all resources. 4220 4221 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4222 (disabled by default). This works when host memory is not 4223 overcommitted and reduces the worst-case latency for guest. 4224 4225 Guest ability to manage power state of host cpus (increasing latency 4226 for other processes on the same host cpu, but decreasing latency for 4227 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4228 works best when host CPU is not overcommitted. When used, host 4229 estimates of CPU cycle and power utilization will be incorrect, not 4230 taking into account guest idle time. 4231ERST 4232 4233DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4234 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4235 " the guest without waiting for gdb to connect; use -S too\n" 4236 " if you want it to not start execution.)\n", 4237 QEMU_ARCH_ALL) 4238SRST 4239``-gdb dev`` 4240 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4241 in the System Emulation Users Guide). Note that this option does not pause QEMU 4242 execution -- if you want QEMU to not start the guest until you 4243 connect with gdb and issue a ``continue`` command, you will need to 4244 also pass the ``-S`` option to QEMU. 4245 4246 The most usual configuration is to listen on a local TCP socket:: 4247 4248 -gdb tcp::3117 4249 4250 but you can specify other backends; UDP, pseudo TTY, or even stdio 4251 are all reasonable use cases. For example, a stdio connection 4252 allows you to start QEMU from within gdb and establish the 4253 connection via a pipe: 4254 4255 .. parsed-literal:: 4256 4257 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4258ERST 4259 4260DEF("s", 0, QEMU_OPTION_s, \ 4261 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4262 QEMU_ARCH_ALL) 4263SRST 4264``-s`` 4265 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4266 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4267ERST 4268 4269DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4270 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4271 QEMU_ARCH_ALL) 4272SRST 4273``-d item1[,...]`` 4274 Enable logging of specified items. Use '-d help' for a list of log 4275 items. 4276ERST 4277 4278DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4279 "-D logfile output log to logfile (default stderr)\n", 4280 QEMU_ARCH_ALL) 4281SRST 4282``-D logfile`` 4283 Output log in logfile instead of to stderr 4284ERST 4285 4286DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4287 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4288 QEMU_ARCH_ALL) 4289SRST 4290``-dfilter range1[,...]`` 4291 Filter debug output to that relevant to a range of target addresses. 4292 The filter spec can be either start+size, start-size or start..end 4293 where start end and size are the addresses and sizes required. For 4294 example: 4295 4296 :: 4297 4298 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4299 4300 Will dump output for any code in the 0x1000 sized block starting at 4301 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4302 another 0x1000 sized block starting at 0xffffffc00005f000. 4303ERST 4304 4305DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4306 "-seed number seed the pseudo-random number generator\n", 4307 QEMU_ARCH_ALL) 4308SRST 4309``-seed number`` 4310 Force the guest to use a deterministic pseudo-random number 4311 generator, seeded with number. This does not affect crypto routines 4312 within the host. 4313ERST 4314 4315DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4316 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4317 QEMU_ARCH_ALL) 4318SRST 4319``-L path`` 4320 Set the directory for the BIOS, VGA BIOS and keymaps. 4321 4322 To list all the data directories, use ``-L help``. 4323ERST 4324 4325DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4326 "-enable-kvm enable KVM full virtualization support\n", 4327 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4328 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4329SRST 4330``-enable-kvm`` 4331 Enable KVM full virtualization support. This option is only 4332 available if KVM support is enabled when compiling. 4333ERST 4334 4335DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4336 "-xen-domid id specify xen guest domain id\n", 4337 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4338DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4339 "-xen-attach attach to existing xen domain\n" 4340 " libxl will use this when starting QEMU\n", 4341 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4342DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4343 "-xen-domid-restrict restrict set of available xen operations\n" 4344 " to specified domain id. (Does not affect\n" 4345 " xenpv machine type).\n", 4346 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4347SRST 4348``-xen-domid id`` 4349 Specify xen guest domain id (XEN only). 4350 4351``-xen-attach`` 4352 Attach to existing xen domain. libxl will use this when starting 4353 QEMU (XEN only). Restrict set of available xen operations to 4354 specified domain id (XEN only). 4355ERST 4356 4357DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4358 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4359SRST 4360``-no-reboot`` 4361 Exit instead of rebooting. 4362ERST 4363 4364DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4365 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4366SRST 4367``-no-shutdown`` 4368 Don't exit QEMU on guest shutdown, but instead only stop the 4369 emulation. This allows for instance switching to monitor to commit 4370 changes to the disk image. 4371ERST 4372 4373DEF("action", HAS_ARG, QEMU_OPTION_action, 4374 "-action reboot=reset|shutdown\n" 4375 " action when guest reboots [default=reset]\n" 4376 "-action shutdown=poweroff|pause\n" 4377 " action when guest shuts down [default=poweroff]\n" 4378 "-action panic=pause|shutdown|exit-failure|none\n" 4379 " action when guest panics [default=shutdown]\n" 4380 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4381 " action when watchdog fires [default=reset]\n", 4382 QEMU_ARCH_ALL) 4383SRST 4384``-action event=action`` 4385 The action parameter serves to modify QEMU's default behavior when 4386 certain guest events occur. It provides a generic method for specifying the 4387 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4388 parameters. 4389 4390 Examples: 4391 4392 ``-action panic=none`` 4393 ``-action reboot=shutdown,shutdown=pause`` 4394 ``-device i6300esb -action watchdog=pause`` 4395 4396ERST 4397 4398DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4399 "-loadvm [tag|id]\n" \ 4400 " start right away with a saved state (loadvm in monitor)\n", 4401 QEMU_ARCH_ALL) 4402SRST 4403``-loadvm file`` 4404 Start right away with a saved state (``loadvm`` in monitor) 4405ERST 4406 4407#ifndef _WIN32 4408DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4409 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4410#endif 4411SRST 4412``-daemonize`` 4413 Daemonize the QEMU process after initialization. QEMU will not 4414 detach from standard IO until it is ready to receive connections on 4415 any of its devices. This option is a useful way for external 4416 programs to launch QEMU without having to cope with initialization 4417 race conditions. 4418ERST 4419 4420DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4421 "-option-rom rom load a file, rom, into the option ROM space\n", 4422 QEMU_ARCH_ALL) 4423SRST 4424``-option-rom file`` 4425 Load the contents of file as an option ROM. This option is useful to 4426 load things like EtherBoot. 4427ERST 4428 4429DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4430 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4431 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4432 QEMU_ARCH_ALL) 4433 4434SRST 4435``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4436 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4437 the current UTC or local time, respectively. ``localtime`` is 4438 required for correct date in MS-DOS or Windows. To start at a 4439 specific point in time, provide datetime in the format 4440 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4441 4442 By default the RTC is driven by the host system time. This allows 4443 using of the RTC as accurate reference clock inside the guest, 4444 specifically if the host time is smoothly following an accurate 4445 external reference clock, e.g. via NTP. If you want to isolate the 4446 guest time from the host, you can set ``clock`` to ``rt`` instead, 4447 which provides a host monotonic clock if host support it. To even 4448 prevent the RTC from progressing during suspension, you can set 4449 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4450 recommended especially in icount mode in order to preserve 4451 determinism; however, note that in icount mode the speed of the 4452 virtual clock is variable and can in general differ from the host 4453 clock. 4454 4455 Enable ``driftfix`` (i386 targets only) if you experience time drift 4456 problems, specifically with Windows' ACPI HAL. This option will try 4457 to figure out how many timer interrupts were not processed by the 4458 Windows guest and will re-inject them. 4459ERST 4460 4461DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4462 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4463 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4464 " instruction, enable aligning the host and virtual clocks\n" \ 4465 " or disable real time cpu sleeping, and optionally enable\n" \ 4466 " record-and-replay mode\n", QEMU_ARCH_ALL) 4467SRST 4468``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4469 Enable virtual instruction counter. The virtual cpu will execute one 4470 instruction every 2^N ns of virtual time. If ``auto`` is specified 4471 then the virtual cpu speed will be automatically adjusted to keep 4472 virtual time within a few seconds of real time. 4473 4474 Note that while this option can give deterministic behavior, it does 4475 not provide cycle accurate emulation. Modern CPUs contain 4476 superscalar out of order cores with complex cache hierarchies. The 4477 number of instructions executed often has little or no correlation 4478 with actual performance. 4479 4480 When the virtual cpu is sleeping, the virtual time will advance at 4481 default speed unless ``sleep=on`` is specified. With 4482 ``sleep=on``, the virtual time will jump to the next timer 4483 deadline instantly whenever the virtual cpu goes to sleep mode and 4484 will not advance if no timer is enabled. This behavior gives 4485 deterministic execution times from the guest point of view. 4486 The default if icount is enabled is ``sleep=off``. 4487 ``sleep=on`` cannot be used together with either ``shift=auto`` 4488 or ``align=on``. 4489 4490 ``align=on`` will activate the delay algorithm which will try to 4491 synchronise the host clock and the virtual clock. The goal is to 4492 have a guest running at the real frequency imposed by the shift 4493 option. Whenever the guest clock is behind the host clock and if 4494 ``align=on`` is specified then we print a message to the user to 4495 inform about the delay. Currently this option does not work when 4496 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4497 shift values for which the guest clock runs ahead of the host clock. 4498 Typically this happens when the shift value is high (how high 4499 depends on the host machine). The default if icount is enabled 4500 is ``align=off``. 4501 4502 When the ``rr`` option is specified deterministic record/replay is 4503 enabled. The ``rrfile=`` option must also be provided to 4504 specify the path to the replay log. In record mode data is written 4505 to this file, and in replay mode it is read back. 4506 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4507 name. In record mode, a new VM snapshot with the given name is created 4508 at the start of execution recording. In replay mode this option 4509 specifies the snapshot name used to load the initial VM state. 4510ERST 4511 4512DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4513 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4514 " action when watchdog fires [default=reset]\n", 4515 QEMU_ARCH_ALL) 4516SRST 4517``-watchdog-action action`` 4518 The action controls what QEMU will do when the watchdog timer 4519 expires. The default is ``reset`` (forcefully reset the guest). 4520 Other possible actions are: ``shutdown`` (attempt to gracefully 4521 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4522 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4523 guest), ``debug`` (print a debug message and continue), or ``none`` 4524 (do nothing). 4525 4526 Note that the ``shutdown`` action requires that the guest responds 4527 to ACPI signals, which it may not be able to do in the sort of 4528 situations where the watchdog would have expired, and thus 4529 ``-watchdog-action shutdown`` is not recommended for production use. 4530 4531 Examples: 4532 4533 ``-device i6300esb -watchdog-action pause`` 4534 4535ERST 4536 4537DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4538 "-echr chr set terminal escape character instead of ctrl-a\n", 4539 QEMU_ARCH_ALL) 4540SRST 4541``-echr numeric_ascii_value`` 4542 Change the escape character used for switching to the monitor when 4543 using monitor and serial sharing. The default is ``0x01`` when using 4544 the ``-nographic`` option. ``0x01`` is equal to pressing 4545 ``Control-a``. You can select a different character from the ascii 4546 control keys where 1 through 26 map to Control-a through Control-z. 4547 For instance you could use the either of the following to change the 4548 escape character to Control-t. 4549 4550 ``-echr 0x14``; \ ``-echr 20`` 4551 4552ERST 4553 4554DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4555 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4556 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4557 "-incoming unix:socketpath\n" \ 4558 " prepare for incoming migration, listen on\n" \ 4559 " specified protocol and socket address\n" \ 4560 "-incoming fd:fd\n" \ 4561 "-incoming exec:cmdline\n" \ 4562 " accept incoming migration on given file descriptor\n" \ 4563 " or from given external command\n" \ 4564 "-incoming defer\n" \ 4565 " wait for the URI to be specified via migrate_incoming\n", 4566 QEMU_ARCH_ALL) 4567SRST 4568``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4569 \ 4570``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4571 Prepare for incoming migration, listen on a given tcp port. 4572 4573``-incoming unix:socketpath`` 4574 Prepare for incoming migration, listen on a given unix socket. 4575 4576``-incoming fd:fd`` 4577 Accept incoming migration from a given filedescriptor. 4578 4579``-incoming exec:cmdline`` 4580 Accept incoming migration as an output from specified external 4581 command. 4582 4583``-incoming defer`` 4584 Wait for the URI to be specified via migrate\_incoming. The monitor 4585 can be used to change settings (such as migration parameters) prior 4586 to issuing the migrate\_incoming to allow the migration to begin. 4587ERST 4588 4589DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4590 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4591SRST 4592``-only-migratable`` 4593 Only allow migratable devices. Devices will not be allowed to enter 4594 an unmigratable state. 4595ERST 4596 4597DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4598 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4599SRST 4600``-nodefaults`` 4601 Don't create default devices. Normally, QEMU sets the default 4602 devices like serial port, parallel port, virtual console, monitor 4603 device, VGA adapter, floppy and CD-ROM drive and others. The 4604 ``-nodefaults`` option will disable all those default devices. 4605ERST 4606 4607#ifndef _WIN32 4608DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4609 "-chroot dir chroot to dir just before starting the VM\n", 4610 QEMU_ARCH_ALL) 4611#endif 4612SRST 4613``-chroot dir`` 4614 Immediately before starting guest execution, chroot to the specified 4615 directory. Especially useful in combination with -runas. 4616ERST 4617 4618#ifndef _WIN32 4619DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4620 "-runas user change to user id user just before starting the VM\n" \ 4621 " user can be numeric uid:gid instead\n", 4622 QEMU_ARCH_ALL) 4623#endif 4624SRST 4625``-runas user`` 4626 Immediately before starting guest execution, drop root privileges, 4627 switching to the specified user. 4628ERST 4629 4630DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4631 "-prom-env variable=value\n" 4632 " set OpenBIOS nvram variables\n", 4633 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4634SRST 4635``-prom-env variable=value`` 4636 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4637 4638 :: 4639 4640 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4641 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4642 4643 :: 4644 4645 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4646 -prom-env 'boot-device=hd:2,\yaboot' \ 4647 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4648ERST 4649DEF("semihosting", 0, QEMU_OPTION_semihosting, 4650 "-semihosting semihosting mode\n", 4651 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4652 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4653SRST 4654``-semihosting`` 4655 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4656 4657 .. warning:: 4658 Note that this allows guest direct access to the host filesystem, so 4659 should only be used with a trusted guest OS. 4660 4661 See the -semihosting-config option documentation for further 4662 information about the facilities this enables. 4663ERST 4664DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4665 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4666 " semihosting configuration\n", 4667QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4668QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4669SRST 4670``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4671 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4672 only). 4673 4674 .. warning:: 4675 Note that this allows guest direct access to the host filesystem, so 4676 should only be used with a trusted guest OS. 4677 4678 ``target=native|gdb|auto`` 4679 Defines where the semihosting calls will be addressed, to QEMU 4680 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4681 means ``gdb`` during debug sessions and ``native`` otherwise. 4682 4683 ``chardev=str1`` 4684 Send the output to a chardev backend output for native or auto 4685 output when not in gdb 4686 4687 ``userspace=on|off`` 4688 Allows code running in guest userspace to access the semihosting 4689 interface. The default is that only privileged guest code can 4690 make semihosting calls. Note that setting ``userspace=on`` should 4691 only be used if all guest code is trusted (for example, in 4692 bare-metal test case code). 4693 4694 ``arg=str1,arg=str2,...`` 4695 Allows the user to pass input arguments, and can be used 4696 multiple times to build up a list. The old-style 4697 ``-kernel``/``-append`` method of passing a command line is 4698 still supported for backward compatibility. If both the 4699 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4700 specified, the former is passed to semihosting as it always 4701 takes precedence. 4702ERST 4703DEF("old-param", 0, QEMU_OPTION_old_param, 4704 "-old-param old param mode\n", QEMU_ARCH_ARM) 4705SRST 4706``-old-param`` 4707 Old param mode (ARM only). 4708ERST 4709 4710DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4711 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4712 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4713 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4714 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4715 " by the kernel, but typically no longer used by modern\n" \ 4716 " C library implementations.\n" \ 4717 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4718 " to elevate privileges using set*uid|gid system calls.\n" \ 4719 " The value 'children' will deny set*uid|gid system calls for\n" \ 4720 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4721 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4722 " blocking *fork and execve\n" \ 4723 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4724 QEMU_ARCH_ALL) 4725SRST 4726``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4727 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4728 filtering and 'off' will disable it. The default is 'off'. 4729 4730 ``obsolete=string`` 4731 Enable Obsolete system calls 4732 4733 ``elevateprivileges=string`` 4734 Disable set\*uid\|gid system calls 4735 4736 ``spawn=string`` 4737 Disable \*fork and execve 4738 4739 ``resourcecontrol=string`` 4740 Disable process affinity and schedular priority 4741ERST 4742 4743DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4744 "-readconfig <file>\n" 4745 " read config file\n", QEMU_ARCH_ALL) 4746SRST 4747``-readconfig file`` 4748 Read device configuration from file. This approach is useful when 4749 you want to spawn QEMU process with many command line options but 4750 you don't want to exceed the command line character limit. 4751ERST 4752 4753DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4754 "-no-user-config\n" 4755 " do not load default user-provided config files at startup\n", 4756 QEMU_ARCH_ALL) 4757SRST 4758``-no-user-config`` 4759 The ``-no-user-config`` option makes QEMU not load any of the 4760 user-provided config files on sysconfdir. 4761ERST 4762 4763DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4764 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4765 " specify tracing options\n", 4766 QEMU_ARCH_ALL) 4767SRST 4768``-trace [[enable=]pattern][,events=file][,file=file]`` 4769 .. include:: ../qemu-option-trace.rst.inc 4770 4771ERST 4772DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4773 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4774 " load a plugin\n", 4775 QEMU_ARCH_ALL) 4776SRST 4777``-plugin file=file[,argname=argvalue]`` 4778 Load a plugin. 4779 4780 ``file=file`` 4781 Load the given plugin from a shared library file. 4782 4783 ``argname=argvalue`` 4784 Argument passed to the plugin. (Can be given multiple times.) 4785ERST 4786 4787HXCOMM Internal use 4788DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4789DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4790 4791#ifdef __linux__ 4792DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4793 "-async-teardown enable asynchronous teardown\n", 4794 QEMU_ARCH_ALL) 4795#endif 4796SRST 4797``-async-teardown`` 4798 Enable asynchronous teardown. A new process called "cleanup/<QEMU_PID>" 4799 will be created at startup sharing the address space with the main qemu 4800 process, using clone. It will wait for the main qemu process to 4801 terminate completely, and then exit. 4802 This allows qemu to terminate very quickly even if the guest was 4803 huge, leaving the teardown of the address space to the cleanup 4804 process. Since the cleanup process shares the same cgroups as the 4805 main qemu process, accounting is performed correctly. This only 4806 works if the cleanup process is not forcefully killed with SIGKILL 4807 before the main qemu process has terminated completely. 4808ERST 4809 4810DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4811 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4812 " control error message format\n" 4813 " timestamp=on enables timestamps (default: off)\n" 4814 " guest-name=on enables guest name prefix but only if\n" 4815 " -name guest option is set (default: off)\n", 4816 QEMU_ARCH_ALL) 4817SRST 4818``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4819 Control error message format. 4820 4821 ``timestamp=on|off`` 4822 Prefix messages with a timestamp. Default is off. 4823 4824 ``guest-name=on|off`` 4825 Prefix messages with guest name but only if -name guest option is set 4826 otherwise the option is ignored. Default is off. 4827ERST 4828 4829DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4830 "-dump-vmstate <file>\n" 4831 " Output vmstate information in JSON format to file.\n" 4832 " Use the scripts/vmstate-static-checker.py file to\n" 4833 " check for possible regressions in migration code\n" 4834 " by comparing two such vmstate dumps.\n", 4835 QEMU_ARCH_ALL) 4836SRST 4837``-dump-vmstate file`` 4838 Dump json-encoded vmstate information for current machine type to 4839 file in file 4840ERST 4841 4842DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4843 "-enable-sync-profile\n" 4844 " enable synchronization profiling\n", 4845 QEMU_ARCH_ALL) 4846SRST 4847``-enable-sync-profile`` 4848 Enable synchronization profiling. 4849ERST 4850 4851#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 4852DEF("perfmap", 0, QEMU_OPTION_perfmap, 4853 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 4854 QEMU_ARCH_ALL) 4855SRST 4856``-perfmap`` 4857 Generate a map file for Linux perf tools that will allow basic profiling 4858 information to be broken down into basic blocks. 4859ERST 4860 4861DEF("jitdump", 0, QEMU_OPTION_jitdump, 4862 "-jitdump generate a jit-${pid}.dump file for perf\n", 4863 QEMU_ARCH_ALL) 4864SRST 4865``-jitdump`` 4866 Generate a dump file for Linux perf tools that maps basic blocks to symbol 4867 names, line numbers and JITted code. 4868ERST 4869#endif 4870 4871DEFHEADING() 4872 4873DEFHEADING(Generic object creation:) 4874 4875DEF("object", HAS_ARG, QEMU_OPTION_object, 4876 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4877 " create a new object of type TYPENAME setting properties\n" 4878 " in the order they are specified. Note that the 'id'\n" 4879 " property must be set. These objects are placed in the\n" 4880 " '/objects' path.\n", 4881 QEMU_ARCH_ALL) 4882SRST 4883``-object typename[,prop1=value1,...]`` 4884 Create a new object of type typename setting properties in the order 4885 they are specified. Note that the 'id' property must be set. These 4886 objects are placed in the '/objects' path. 4887 4888 ``-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`` 4889 Creates a memory file backend object, which can be used to back 4890 the guest RAM with huge pages. 4891 4892 The ``id`` parameter is a unique ID that will be used to 4893 reference this memory region in other parameters, e.g. ``-numa``, 4894 ``-device nvdimm``, etc. 4895 4896 The ``size`` option provides the size of the memory region, and 4897 accepts common suffixes, e.g. ``500M``. 4898 4899 The ``mem-path`` provides the path to either a shared memory or 4900 huge page filesystem mount. 4901 4902 The ``share`` boolean option determines whether the memory 4903 region is marked as private to QEMU, or shared. The latter 4904 allows a co-operating external process to access the QEMU memory 4905 region. 4906 4907 The ``share`` is also required for pvrdma devices due to 4908 limitations in the RDMA API provided by Linux. 4909 4910 Setting share=on might affect the ability to configure NUMA 4911 bindings for the memory backend under some circumstances, see 4912 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4913 source tree for additional details. 4914 4915 Setting the ``discard-data`` boolean option to on indicates that 4916 file contents can be destroyed when QEMU exits, to avoid 4917 unnecessarily flushing data to the backing file. Note that 4918 ``discard-data`` is only an optimization, and QEMU might not 4919 discard file contents if it aborts unexpectedly or is terminated 4920 using SIGKILL. 4921 4922 The ``merge`` boolean option enables memory merge, also known as 4923 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4924 the pages for memory deduplication. 4925 4926 Setting the ``dump`` boolean option to off excludes the memory 4927 from core dumps. This feature is also known as MADV\_DONTDUMP. 4928 4929 The ``prealloc`` boolean option enables memory preallocation. 4930 4931 The ``host-nodes`` option binds the memory range to a list of 4932 NUMA host nodes. 4933 4934 The ``policy`` option sets the NUMA policy to one of the 4935 following values: 4936 4937 ``default`` 4938 default host policy 4939 4940 ``preferred`` 4941 prefer the given host node list for allocation 4942 4943 ``bind`` 4944 restrict memory allocation to the given host node list 4945 4946 ``interleave`` 4947 interleave memory allocations across the given host node 4948 list 4949 4950 The ``align`` option specifies the base address alignment when 4951 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4952 ``2M``. Some backend store specified by ``mem-path`` requires an 4953 alignment different than the default one used by QEMU, eg the 4954 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4955 such cases, users can specify the required alignment via this 4956 option. 4957 4958 The ``pmem`` option specifies whether the backing file specified 4959 by ``mem-path`` is in host persistent memory that can be 4960 accessed using the SNIA NVM programming model (e.g. Intel 4961 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4962 operations to guarantee the persistence of its own writes to 4963 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4964 migration). Also, we will map the backend-file with MAP\_SYNC 4965 flag, which ensures the file metadata is in sync for 4966 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4967 requires support from both the host kernel (since Linux kernel 4968 4.15) and the filesystem of ``mem-path`` mounted with DAX 4969 option. 4970 4971 The ``readonly`` option specifies whether the backing file is opened 4972 read-only or read-write (default). 4973 4974 ``-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`` 4975 Creates a memory backend object, which can be used to back the 4976 guest RAM. Memory backend objects offer more control than the 4977 ``-m`` option that is traditionally used to define guest RAM. 4978 Please refer to ``memory-backend-file`` for a description of the 4979 options. 4980 4981 ``-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`` 4982 Creates an anonymous memory file backend object, which allows 4983 QEMU to share the memory with an external process (e.g. when 4984 using vhost-user). The memory is allocated with memfd and 4985 optional sealing. (Linux only) 4986 4987 The ``seal`` option creates a sealed-file, that will block 4988 further resizing the memory ('on' by default). 4989 4990 The ``hugetlb`` option specify the file to be created resides in 4991 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4992 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4993 the hugetlb page size on systems that support multiple hugetlb 4994 page sizes (it must be a power of 2 value supported by the 4995 system). 4996 4997 In some versions of Linux, the ``hugetlb`` option is 4998 incompatible with the ``seal`` option (requires at least Linux 4999 4.16). 5000 5001 Please refer to ``memory-backend-file`` for a description of the 5002 other options. 5003 5004 The ``share`` boolean option is on by default with memfd. 5005 5006 ``-object rng-builtin,id=id`` 5007 Creates a random number generator backend which obtains entropy 5008 from QEMU builtin functions. The ``id`` parameter is a unique ID 5009 that will be used to reference this entropy backend from the 5010 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5011 uses this RNG backend. 5012 5013 ``-object rng-random,id=id,filename=/dev/random`` 5014 Creates a random number generator backend which obtains entropy 5015 from a device on the host. The ``id`` parameter is a unique ID 5016 that will be used to reference this entropy backend from the 5017 ``virtio-rng`` device. The ``filename`` parameter specifies 5018 which file to obtain entropy from and if omitted defaults to 5019 ``/dev/urandom``. 5020 5021 ``-object rng-egd,id=id,chardev=chardevid`` 5022 Creates a random number generator backend which obtains entropy 5023 from an external daemon running on the host. The ``id`` 5024 parameter is a unique ID that will be used to reference this 5025 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5026 parameter is the unique ID of a character device backend that 5027 provides the connection to the RNG daemon. 5028 5029 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5030 Creates a TLS anonymous credentials object, which can be used to 5031 provide TLS support on network backends. The ``id`` parameter is 5032 a unique ID which network backends will use to access the 5033 credentials. The ``endpoint`` is either ``server`` or ``client`` 5034 depending on whether the QEMU network backend that uses the 5035 credentials will be acting as a client or as a server. If 5036 ``verify-peer`` is enabled (the default) then once the handshake 5037 is completed, the peer credentials will be verified, though this 5038 is a no-op for anonymous credentials. 5039 5040 The dir parameter tells QEMU where to find the credential files. 5041 For server endpoints, this directory may contain a file 5042 dh-params.pem providing diffie-hellman parameters to use for the 5043 TLS server. If the file is missing, QEMU will generate a set of 5044 DH parameters at startup. This is a computationally expensive 5045 operation that consumes random pool entropy, so it is 5046 recommended that a persistent set of parameters be generated 5047 upfront and saved. 5048 5049 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5050 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5051 can be used to provide TLS support on network backends. The 5052 ``id`` parameter is a unique ID which network backends will use 5053 to access the credentials. The ``endpoint`` is either ``server`` 5054 or ``client`` depending on whether the QEMU network backend that 5055 uses the credentials will be acting as a client or as a server. 5056 For clients only, ``username`` is the username which will be 5057 sent to the server. If omitted it defaults to "qemu". 5058 5059 The dir parameter tells QEMU where to find the keys file. It is 5060 called "dir/keys.psk" and contains "username:key" pairs. This 5061 file can most easily be created using the GnuTLS ``psktool`` 5062 program. 5063 5064 For server endpoints, dir may also contain a file dh-params.pem 5065 providing diffie-hellman parameters to use for the TLS server. 5066 If the file is missing, QEMU will generate a set of DH 5067 parameters at startup. This is a computationally expensive 5068 operation that consumes random pool entropy, so it is 5069 recommended that a persistent set of parameters be generated up 5070 front and saved. 5071 5072 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5073 Creates a TLS anonymous credentials object, which can be used to 5074 provide TLS support on network backends. The ``id`` parameter is 5075 a unique ID which network backends will use to access the 5076 credentials. The ``endpoint`` is either ``server`` or ``client`` 5077 depending on whether the QEMU network backend that uses the 5078 credentials will be acting as a client or as a server. If 5079 ``verify-peer`` is enabled (the default) then once the handshake 5080 is completed, the peer credentials will be verified. With x509 5081 certificates, this implies that the clients must be provided 5082 with valid client certificates too. 5083 5084 The dir parameter tells QEMU where to find the credential files. 5085 For server endpoints, this directory may contain a file 5086 dh-params.pem providing diffie-hellman parameters to use for the 5087 TLS server. If the file is missing, QEMU will generate a set of 5088 DH parameters at startup. This is a computationally expensive 5089 operation that consumes random pool entropy, so it is 5090 recommended that a persistent set of parameters be generated 5091 upfront and saved. 5092 5093 For x509 certificate credentials the directory will contain 5094 further files providing the x509 certificates. The certificates 5095 must be stored in PEM format, in filenames ca-cert.pem, 5096 ca-crl.pem (optional), server-cert.pem (only servers), 5097 server-key.pem (only servers), client-cert.pem (only clients), 5098 and client-key.pem (only clients). 5099 5100 For the server-key.pem and client-key.pem files which contain 5101 sensitive private keys, it is possible to use an encrypted 5102 version by providing the passwordid parameter. This provides the 5103 ID of a previously created ``secret`` object containing the 5104 password for decryption. 5105 5106 The priority parameter allows to override the global default 5107 priority used by gnutls. This can be useful if the system 5108 administrator needs to use a weaker set of crypto priorities for 5109 QEMU without potentially forcing the weakness onto all 5110 applications. Or conversely if one wants wants a stronger 5111 default for QEMU than for all other applications, they can do 5112 this through this parameter. Its format is a gnutls priority 5113 string as described at 5114 https://gnutls.org/manual/html_node/Priority-Strings.html. 5115 5116 ``-object tls-cipher-suites,id=id,priority=priority`` 5117 Creates a TLS cipher suites object, which can be used to control 5118 the TLS cipher/protocol algorithms that applications are permitted 5119 to use. 5120 5121 The ``id`` parameter is a unique ID which frontends will use to 5122 access the ordered list of permitted TLS cipher suites from the 5123 host. 5124 5125 The ``priority`` parameter allows to override the global default 5126 priority used by gnutls. This can be useful if the system 5127 administrator needs to use a weaker set of crypto priorities for 5128 QEMU without potentially forcing the weakness onto all 5129 applications. Or conversely if one wants wants a stronger 5130 default for QEMU than for all other applications, they can do 5131 this through this parameter. Its format is a gnutls priority 5132 string as described at 5133 https://gnutls.org/manual/html_node/Priority-Strings.html. 5134 5135 An example of use of this object is to control UEFI HTTPS Boot. 5136 The tls-cipher-suites object exposes the ordered list of permitted 5137 TLS cipher suites from the host side to the guest firmware, via 5138 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5139 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5140 guest-side TLS. 5141 5142 In the following example, the priority at which the host-side policy 5143 is retrieved is given by the ``priority`` property. 5144 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5145 refer to /etc/crypto-policies/back-ends/gnutls.config. 5146 5147 .. parsed-literal:: 5148 5149 # |qemu_system| \\ 5150 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5151 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5152 5153 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5154 Interval t can't be 0, this filter batches the packet delivery: 5155 all packets arriving in a given interval on netdev netdevid are 5156 delayed until the end of the interval. Interval is in 5157 microseconds. ``status`` is optional that indicate whether the 5158 netfilter is on (enabled) or off (disabled), the default status 5159 for netfilter will be 'on'. 5160 5161 queue all\|rx\|tx is an option that can be applied to any 5162 netfilter. 5163 5164 ``all``: the filter is attached both to the receive and the 5165 transmit queue of the netdev (default). 5166 5167 ``rx``: the filter is attached to the receive queue of the 5168 netdev, where it will receive packets sent to the netdev. 5169 5170 ``tx``: the filter is attached to the transmit queue of the 5171 netdev, where it will receive packets sent by the netdev. 5172 5173 position head\|tail\|id=<id> is an option to specify where the 5174 filter should be inserted in the filter list. It can be applied 5175 to any netfilter. 5176 5177 ``head``: the filter is inserted at the head of the filter list, 5178 before any existing filters. 5179 5180 ``tail``: the filter is inserted at the tail of the filter list, 5181 behind any existing filters (default). 5182 5183 ``id=<id>``: the filter is inserted before or behind the filter 5184 specified by <id>, see the insert option below. 5185 5186 insert behind\|before is an option to specify where to insert 5187 the new filter relative to the one specified with 5188 position=id=<id>. It can be applied to any netfilter. 5189 5190 ``before``: insert before the specified filter. 5191 5192 ``behind``: insert behind the specified filter (default). 5193 5194 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5195 filter-mirror on netdev netdevid,mirror net packet to 5196 chardevchardevid, if it has the vnet\_hdr\_support flag, 5197 filter-mirror will mirror packet with vnet\_hdr\_len. 5198 5199 ``-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]`` 5200 filter-redirector on netdev netdevid,redirect filter's net 5201 packet to chardev chardevid,and redirect indev's packet to 5202 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5203 will redirect packet with vnet\_hdr\_len. Create a 5204 filter-redirector we need to differ outdev id from indev id, id 5205 can not be the same. we can just use indev or outdev, but at 5206 least one of indev or outdev need to be specified. 5207 5208 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5209 Filter-rewriter is a part of COLO project.It will rewrite tcp 5210 packet to secondary from primary to keep secondary tcp 5211 connection,and rewrite tcp packet to primary from secondary make 5212 tcp packet can be handled by client.if it has the 5213 vnet\_hdr\_support flag, we can parse packet with vnet header. 5214 5215 usage: colo secondary: -object 5216 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5217 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5218 filter-rewriter,id=rew0,netdev=hn0,queue=all 5219 5220 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5221 Dump the network traffic on netdev dev to the file specified by 5222 filename. At most len bytes (64k by default) per packet are 5223 stored. The file format is libpcap, so it can be analyzed with 5224 tools such as tcpdump or Wireshark. 5225 5226 ``-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}]`` 5227 Colo-compare gets packet from primary\_in chardevid and 5228 secondary\_in, then compare whether the payload of primary packet 5229 and secondary packet are the same. If same, it will output 5230 primary packet to out\_dev, else it will notify COLO-framework to do 5231 checkpoint and send primary packet to out\_dev. In order to 5232 improve efficiency, we need to put the task of comparison in 5233 another iothread. If it has the vnet\_hdr\_support flag, 5234 colo compare will send/recv packet with vnet\_hdr\_len. 5235 The compare\_timeout=@var{ms} determines the maximum time of the 5236 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5237 is to set the period of scanning expired primary node network packets. 5238 The max\_queue\_size=@var{size} is to set the max compare queue 5239 size depend on user environment. 5240 If user want to use Xen COLO, need to add the notify\_dev to 5241 notify Xen colo-frame to do checkpoint. 5242 5243 COLO-compare must be used with the help of filter-mirror, 5244 filter-redirector and filter-rewriter. 5245 5246 :: 5247 5248 KVM COLO 5249 5250 primary: 5251 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5252 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5253 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5254 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5255 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5256 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5257 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5258 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5259 -object iothread,id=iothread1 5260 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5261 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5262 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5263 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5264 5265 secondary: 5266 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5267 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5268 -chardev socket,id=red0,host=3.3.3.3,port=9003 5269 -chardev socket,id=red1,host=3.3.3.3,port=9004 5270 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5271 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5272 5273 5274 Xen COLO 5275 5276 primary: 5277 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5278 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5279 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5280 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5281 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5282 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5283 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5284 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5285 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5286 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5287 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5288 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5289 -object iothread,id=iothread1 5290 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5291 5292 secondary: 5293 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5294 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5295 -chardev socket,id=red0,host=3.3.3.3,port=9003 5296 -chardev socket,id=red1,host=3.3.3.3,port=9004 5297 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5298 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5299 5300 If you want to know the detail of above command line, you can 5301 read the colo-compare git log. 5302 5303 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5304 Creates a cryptodev backend which executes crypto operations from 5305 the QEMU cipher APIs. The id parameter is a unique ID that will 5306 be used to reference this cryptodev backend from the 5307 ``virtio-crypto`` device. The queues parameter is optional, 5308 which specify the queue number of cryptodev backend, the default 5309 of queues is 1. 5310 5311 .. parsed-literal:: 5312 5313 # |qemu_system| \\ 5314 [...] \\ 5315 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5316 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5317 [...] 5318 5319 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5320 Creates a vhost-user cryptodev backend, backed by a chardev 5321 chardevid. The id parameter is a unique ID that will be used to 5322 reference this cryptodev backend from the ``virtio-crypto`` 5323 device. The chardev should be a unix domain socket backed one. 5324 The vhost-user uses a specifically defined protocol to pass 5325 vhost ioctl replacement messages to an application on the other 5326 end of the socket. The queues parameter is optional, which 5327 specify the queue number of cryptodev backend for multiqueue 5328 vhost-user, the default of queues is 1. 5329 5330 .. parsed-literal:: 5331 5332 # |qemu_system| \\ 5333 [...] \\ 5334 -chardev socket,id=chardev0,path=/path/to/socket \\ 5335 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5336 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5337 [...] 5338 5339 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5340 \ 5341 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5342 Defines a secret to store a password, encryption key, or some 5343 other sensitive data. The sensitive data can either be passed 5344 directly via the data parameter, or indirectly via the file 5345 parameter. Using the data parameter is insecure unless the 5346 sensitive data is encrypted. 5347 5348 The sensitive data can be provided in raw format (the default), 5349 or base64. When encoded as JSON, the raw format only supports 5350 valid UTF-8 characters, so base64 is recommended for sending 5351 binary data. QEMU will convert from which ever format is 5352 provided to the format it needs internally. eg, an RBD password 5353 can be provided in raw format, even though it will be base64 5354 encoded when passed onto the RBD sever. 5355 5356 For added protection, it is possible to encrypt the data 5357 associated with a secret using the AES-256-CBC cipher. Use of 5358 encryption is indicated by providing the keyid and iv 5359 parameters. The keyid parameter provides the ID of a previously 5360 defined secret that contains the AES-256 decryption key. This 5361 key should be 32-bytes long and be base64 encoded. The iv 5362 parameter provides the random initialization vector used for 5363 encryption of this particular secret and should be a base64 5364 encrypted string of the 16-byte IV. 5365 5366 The simplest (insecure) usage is to provide the secret inline 5367 5368 .. parsed-literal:: 5369 5370 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5371 5372 The simplest secure usage is to provide the secret via a file 5373 5374 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5375 secret,id=sec0,file=mypasswd.txt,format=raw 5376 5377 For greater security, AES-256-CBC should be used. To illustrate 5378 usage, consider the openssl command line tool which can encrypt 5379 the data. Note that when encrypting, the plaintext must be 5380 padded to the cipher block size (32 bytes) using the standard 5381 PKCS#5/6 compatible padding algorithm. 5382 5383 First a master key needs to be created in base64 encoding: 5384 5385 :: 5386 5387 # openssl rand -base64 32 > key.b64 5388 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5389 5390 Each secret to be encrypted needs to have a random 5391 initialization vector generated. These do not need to be kept 5392 secret 5393 5394 :: 5395 5396 # openssl rand -base64 16 > iv.b64 5397 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5398 5399 The secret to be defined can now be encrypted, in this case 5400 we're telling openssl to base64 encode the result, but it could 5401 be left as raw bytes if desired. 5402 5403 :: 5404 5405 # SECRET=$(printf "letmein" | 5406 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5407 5408 When launching QEMU, create a master secret pointing to 5409 ``key.b64`` and specify that to be used to decrypt the user 5410 password. Pass the contents of ``iv.b64`` to the second secret 5411 5412 .. parsed-literal:: 5413 5414 # |qemu_system| \\ 5415 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5416 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5417 data=$SECRET,iv=$(<iv.b64) 5418 5419 ``-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]`` 5420 Create a Secure Encrypted Virtualization (SEV) guest object, 5421 which can be used to provide the guest memory encryption support 5422 on AMD processors. 5423 5424 When memory encryption is enabled, one of the physical address 5425 bit (aka the C-bit) is utilized to mark if a memory page is 5426 protected. The ``cbitpos`` is used to provide the C-bit 5427 position. The C-bit position is Host family dependent hence user 5428 must provide this value. On EPYC, the value should be 47. 5429 5430 When memory encryption is enabled, we loose certain bits in 5431 physical address space. The ``reduced-phys-bits`` is used to 5432 provide the number of bits we loose in physical address space. 5433 Similar to C-bit, the value is Host family dependent. On EPYC, 5434 the value should be 5. 5435 5436 The ``sev-device`` provides the device file to use for 5437 communicating with the SEV firmware running inside AMD Secure 5438 Processor. The default device is '/dev/sev'. If hardware 5439 supports memory encryption then /dev/sev devices are created by 5440 CCP driver. 5441 5442 The ``policy`` provides the guest policy to be enforced by the 5443 SEV firmware and restrict what configuration and operational 5444 commands can be performed on this guest by the hypervisor. The 5445 policy should be provided by the guest owner and is bound to the 5446 guest and cannot be changed throughout the lifetime of the 5447 guest. The default is 0. 5448 5449 If guest ``policy`` allows sharing the key with another SEV 5450 guest then ``handle`` can be use to provide handle of the guest 5451 from which to share the key. 5452 5453 The ``dh-cert-file`` and ``session-file`` provides the guest 5454 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5455 and session parameters are used for establishing a cryptographic 5456 session with the guest owner to negotiate keys used for 5457 attestation. The file must be encoded in base64. 5458 5459 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5460 cmdline to a designated guest firmware page for measured Linux 5461 boot with -kernel. The default is off. (Since 6.2) 5462 5463 e.g to launch a SEV guest 5464 5465 .. parsed-literal:: 5466 5467 # |qemu_system_x86| \\ 5468 ...... \\ 5469 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5470 -machine ...,memory-encryption=sev0 \\ 5471 ..... 5472 5473 ``-object authz-simple,id=id,identity=string`` 5474 Create an authorization object that will control access to 5475 network services. 5476 5477 The ``identity`` parameter is identifies the user and its format 5478 depends on the network service that authorization object is 5479 associated with. For authorizing based on TLS x509 certificates, 5480 the identity must be the x509 distinguished name. Note that care 5481 must be taken to escape any commas in the distinguished name. 5482 5483 An example authorization object to validate a x509 distinguished 5484 name would look like: 5485 5486 .. parsed-literal:: 5487 5488 # |qemu_system| \\ 5489 ... \\ 5490 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5491 ... 5492 5493 Note the use of quotes due to the x509 distinguished name 5494 containing whitespace, and escaping of ','. 5495 5496 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5497 Create an authorization object that will control access to 5498 network services. 5499 5500 The ``filename`` parameter is the fully qualified path to a file 5501 containing the access control list rules in JSON format. 5502 5503 An example set of rules that match against SASL usernames might 5504 look like: 5505 5506 :: 5507 5508 { 5509 "rules": [ 5510 { "match": "fred", "policy": "allow", "format": "exact" }, 5511 { "match": "bob", "policy": "allow", "format": "exact" }, 5512 { "match": "danb", "policy": "deny", "format": "glob" }, 5513 { "match": "dan*", "policy": "allow", "format": "exact" }, 5514 ], 5515 "policy": "deny" 5516 } 5517 5518 When checking access the object will iterate over all the rules 5519 and the first rule to match will have its ``policy`` value 5520 returned as the result. If no rules match, then the default 5521 ``policy`` value is returned. 5522 5523 The rules can either be an exact string match, or they can use 5524 the simple UNIX glob pattern matching to allow wildcards to be 5525 used. 5526 5527 If ``refresh`` is set to true the file will be monitored and 5528 automatically reloaded whenever its content changes. 5529 5530 As with the ``authz-simple`` object, the format of the identity 5531 strings being matched depends on the network service, but is 5532 usually a TLS x509 distinguished name, or a SASL username. 5533 5534 An example authorization object to validate a SASL username 5535 would look like: 5536 5537 .. parsed-literal:: 5538 5539 # |qemu_system| \\ 5540 ... \\ 5541 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5542 ... 5543 5544 ``-object authz-pam,id=id,service=string`` 5545 Create an authorization object that will control access to 5546 network services. 5547 5548 The ``service`` parameter provides the name of a PAM service to 5549 use for authorization. It requires that a file 5550 ``/etc/pam.d/service`` exist to provide the configuration for 5551 the ``account`` subsystem. 5552 5553 An example authorization object to validate a TLS x509 5554 distinguished name would look like: 5555 5556 .. parsed-literal:: 5557 5558 # |qemu_system| \\ 5559 ... \\ 5560 -object authz-pam,id=auth0,service=qemu-vnc \\ 5561 ... 5562 5563 There would then be a corresponding config file for PAM at 5564 ``/etc/pam.d/qemu-vnc`` that contains: 5565 5566 :: 5567 5568 account requisite pam_listfile.so item=user sense=allow \ 5569 file=/etc/qemu/vnc.allow 5570 5571 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5572 of x509 distinguished names that are permitted access 5573 5574 :: 5575 5576 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5577 5578 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5579 Creates a dedicated event loop thread that devices can be 5580 assigned to. This is known as an IOThread. By default device 5581 emulation happens in vCPU threads or the main event loop thread. 5582 This can become a scalability bottleneck. IOThreads allow device 5583 emulation and I/O to run on other host CPUs. 5584 5585 The ``id`` parameter is a unique ID that will be used to 5586 reference this IOThread from ``-device ...,iothread=id``. 5587 Multiple devices can be assigned to an IOThread. Note that not 5588 all devices support an ``iothread`` parameter. 5589 5590 The ``query-iothreads`` QMP command lists IOThreads and reports 5591 their thread IDs so that the user can configure host CPU 5592 pinning/affinity. 5593 5594 IOThreads use an adaptive polling algorithm to reduce event loop 5595 latency. Instead of entering a blocking system call to monitor 5596 file descriptors and then pay the cost of being woken up when an 5597 event occurs, the polling algorithm spins waiting for events for 5598 a short time. The algorithm's default parameters are suitable 5599 for many cases but can be adjusted based on knowledge of the 5600 workload and/or host device latency. 5601 5602 The ``poll-max-ns`` parameter is the maximum number of 5603 nanoseconds to busy wait for events. Polling can be disabled by 5604 setting this value to 0. 5605 5606 The ``poll-grow`` parameter is the multiplier used to increase 5607 the polling time when the algorithm detects it is missing events 5608 due to not polling long enough. 5609 5610 The ``poll-shrink`` parameter is the divisor used to decrease 5611 the polling time when the algorithm detects it is spending too 5612 long polling without encountering events. 5613 5614 The ``aio-max-batch`` parameter is the maximum number of requests 5615 in a batch for the AIO engine, 0 means that the engine will use 5616 its default. 5617 5618 The IOThread parameters can be modified at run-time using the 5619 ``qom-set`` command (where ``iothread1`` is the IOThread's 5620 ``id``): 5621 5622 :: 5623 5624 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5625ERST 5626 5627 5628HXCOMM This is the last statement. Insert new options before this line! 5629 5630#undef DEF 5631#undef DEFHEADING 5632#undef ARCHHEADING 5633
