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