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 '\ ``memdev``\ ' option assigns RAM from a given memory backend 409 device to a node. It is recommended to use '\ ``memdev``\ ' option 410 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 411 option provides better performance and more control over the 412 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 413 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 414 415 For compatibility reasons, legacy '\ ``mem``\ ' option is 416 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 417 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 418 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 419 option, and vice versa. 420 421 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 422 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 423 for '\ ``-numa node``\ ' without memory specified was removed. 424 425 '\ ``initiator``\ ' is an additional option that points to an 426 initiator NUMA node that has best performance (the lowest latency or 427 largest bandwidth) to this NUMA node. Note that this option can be 428 set only when the machine property 'hmat' is set to 'on'. 429 430 Following example creates a machine with 2 NUMA nodes, node 0 has 431 CPU. node 1 has only memory, and its initiator is node 0. Note that 432 because node 0 has CPU, by default the initiator of node 0 is itself 433 and must be itself. 434 435 :: 436 437 -machine hmat=on \ 438 -m 2G,slots=2,maxmem=4G \ 439 -object memory-backend-ram,size=1G,id=m0 \ 440 -object memory-backend-ram,size=1G,id=m1 \ 441 -numa node,nodeid=0,memdev=m0 \ 442 -numa node,nodeid=1,memdev=m1,initiator=0 \ 443 -smp 2,sockets=2,maxcpus=2 \ 444 -numa cpu,node-id=0,socket-id=0 \ 445 -numa cpu,node-id=0,socket-id=1 446 447 source and destination are NUMA node IDs. distance is the NUMA 448 distance from source to destination. The distance from a node to 449 itself is always 10. If any pair of nodes is given a distance, then 450 all pairs must be given distances. Although, when distances are only 451 given in one direction for each pair of nodes, then the distances in 452 the opposite directions are assumed to be the same. If, however, an 453 asymmetrical pair of distances is given for even one node pair, then 454 all node pairs must be provided distance values for both directions, 455 even when they are symmetrical. When a node is unreachable from 456 another node, set the pair's distance to 255. 457 458 Note that the -``numa`` option doesn't allocate any of the specified 459 resources, it just assigns existing resources to NUMA nodes. This 460 means that one still has to use the ``-m``, ``-smp`` options to 461 allocate RAM and VCPUs respectively. 462 463 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 464 Information between initiator and target NUMA nodes in ACPI 465 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 466 create memory requests, usually it has one or more processors. 467 Target NUMA node contains addressable memory. 468 469 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 470 the memory hierarchy of the target NUMA node: if hierarchy is 471 'memory', the structure represents the memory performance; if 472 hierarchy is 'first-level\|second-level\|third-level', this 473 structure represents aggregated performance of memory side caches 474 for each domain. type of 'data-type' is type of data represented by 475 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 476 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 477 the target memory; if 'hierarchy' is 478 'first-level\|second-level\|third-level', 'data-type' is 479 'access\|read\|write' hit latency or 'access\|read\|write' hit 480 bandwidth of the target memory side cache. 481 482 lat is latency value in nanoseconds. bw is bandwidth value, the 483 possible value and units are NUM[M\|G\|T], mean that the bandwidth 484 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 485 used suffix). Note that if latency or bandwidth value is 0, means 486 the corresponding latency or bandwidth information is not provided. 487 488 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 489 belongs. size is the size of memory side cache in bytes. level is 490 the cache level described in this structure, note that the cache 491 level 0 should not be used with '\ ``hmat-cache``\ ' option. 492 associativity is the cache associativity, the possible value is 493 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 494 is the write policy. line is the cache Line size in bytes. 495 496 For example, the following options describe 2 NUMA nodes. Node 0 has 497 2 cpus and a ram, node 1 has only a ram. The processors in node 0 498 access memory in node 0 with access-latency 5 nanoseconds, 499 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 500 memory in NUMA node 1 with access-latency 10 nanoseconds, 501 access-bandwidth is 100 MB/s. And for memory side cache information, 502 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 503 policy is write-back, the cache Line size is 8 bytes: 504 505 :: 506 507 -machine hmat=on \ 508 -m 2G \ 509 -object memory-backend-ram,size=1G,id=m0 \ 510 -object memory-backend-ram,size=1G,id=m1 \ 511 -smp 2,sockets=2,maxcpus=2 \ 512 -numa node,nodeid=0,memdev=m0 \ 513 -numa node,nodeid=1,memdev=m1,initiator=0 \ 514 -numa cpu,node-id=0,socket-id=0 \ 515 -numa cpu,node-id=0,socket-id=1 \ 516 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 517 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 518 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 519 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 520 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 521 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 522ERST 523 524DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 525 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 526 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 527SRST 528``-add-fd fd=fd,set=set[,opaque=opaque]`` 529 Add a file descriptor to an fd set. Valid options are: 530 531 ``fd=fd`` 532 This option defines the file descriptor of which a duplicate is 533 added to fd set. The file descriptor cannot be stdin, stdout, or 534 stderr. 535 536 ``set=set`` 537 This option defines the ID of the fd set to add the file 538 descriptor to. 539 540 ``opaque=opaque`` 541 This option defines a free-form string that can be used to 542 describe fd. 543 544 You can open an image using pre-opened file descriptors from an fd 545 set: 546 547 .. parsed-literal:: 548 549 |qemu_system| \\ 550 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 551 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 552 -drive file=/dev/fdset/2,index=0,media=disk 553ERST 554 555DEF("set", HAS_ARG, QEMU_OPTION_set, 556 "-set group.id.arg=value\n" 557 " set <arg> parameter for item <id> of type <group>\n" 558 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 559SRST 560``-set group.id.arg=value`` 561 Set parameter arg for item id of type group 562ERST 563 564DEF("global", HAS_ARG, QEMU_OPTION_global, 565 "-global driver.property=value\n" 566 "-global driver=driver,property=property,value=value\n" 567 " set a global default for a driver property\n", 568 QEMU_ARCH_ALL) 569SRST 570``-global driver.prop=value`` 571 \ 572``-global driver=driver,property=property,value=value`` 573 Set default value of driver's property prop to value, e.g.: 574 575 .. parsed-literal:: 576 577 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 578 579 In particular, you can use this to set driver properties for devices 580 which are created automatically by the machine model. To create a 581 device which is not created automatically and set properties on it, 582 use -``device``. 583 584 -global driver.prop=value is shorthand for -global 585 driver=driver,property=prop,value=value. The longhand syntax works 586 even when driver contains a dot. 587ERST 588 589DEF("boot", HAS_ARG, QEMU_OPTION_boot, 590 "-boot [order=drives][,once=drives][,menu=on|off]\n" 591 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 592 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 593 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 594 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 595 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 596 QEMU_ARCH_ALL) 597SRST 598``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 599 Specify boot order drives as a string of drive letters. Valid drive 600 letters depend on the target architecture. The x86 PC uses: a, b 601 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 602 (Etherboot from network adapter 1-4), hard disk boot is the default. 603 To apply a particular boot order only on the first startup, specify 604 it via ``once``. Note that the ``order`` or ``once`` parameter 605 should not be used together with the ``bootindex`` property of 606 devices, since the firmware implementations normally do not support 607 both at the same time. 608 609 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 610 as firmware/BIOS supports them. The default is non-interactive boot. 611 612 A splash picture could be passed to bios, enabling user to show it 613 as logo, when option splash=sp\_name is given and menu=on, If 614 firmware/BIOS supports them. Currently Seabios for X86 system 615 support it. limitation: The splash file could be a jpeg file or a 616 BMP file in 24 BPP format(true color). The resolution should be 617 supported by the SVGA mode, so the recommended is 320x240, 640x480, 618 800x640. 619 620 A timeout could be passed to bios, guest will pause for rb\_timeout 621 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 622 not reboot, qemu passes '-1' to bios by default. Currently Seabios 623 for X86 system support it. 624 625 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 626 it. This only effects when boot priority is changed by bootindex 627 options. The default is non-strict boot. 628 629 .. parsed-literal:: 630 631 # try to boot from network first, then from hard disk 632 |qemu_system_x86| -boot order=nc 633 # boot from CD-ROM first, switch back to default order after reboot 634 |qemu_system_x86| -boot once=d 635 # boot with a splash picture for 5 seconds. 636 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 637 638 Note: The legacy format '-boot drives' is still supported but its 639 use is discouraged as it may be removed from future versions. 640ERST 641 642DEF("m", HAS_ARG, QEMU_OPTION_m, 643 "-m [size=]megs[,slots=n,maxmem=size]\n" 644 " configure guest RAM\n" 645 " size: initial amount of guest memory\n" 646 " slots: number of hotplug slots (default: none)\n" 647 " maxmem: maximum amount of guest memory (default: none)\n" 648 "NOTE: Some architectures might enforce a specific granularity\n", 649 QEMU_ARCH_ALL) 650SRST 651``-m [size=]megs[,slots=n,maxmem=size]`` 652 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 653 Optionally, a suffix of "M" or "G" can be used to signify a value in 654 megabytes or gigabytes respectively. Optional pair slots, maxmem 655 could be used to set amount of hotpluggable memory slots and maximum 656 amount of memory. Note that maxmem must be aligned to the page size. 657 658 For example, the following command-line sets the guest startup RAM 659 size to 1GB, creates 3 slots to hotplug additional memory and sets 660 the maximum memory the guest can reach to 4GB: 661 662 .. parsed-literal:: 663 664 |qemu_system| -m 1G,slots=3,maxmem=4G 665 666 If slots and maxmem are not specified, memory hotplug won't be 667 enabled and the guest startup RAM will never increase. 668ERST 669 670DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 671 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 672SRST 673``-mem-path path`` 674 Allocate guest RAM from a temporarily created file in path. 675ERST 676 677DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 678 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 679 QEMU_ARCH_ALL) 680SRST 681``-mem-prealloc`` 682 Preallocate memory when using -mem-path. 683ERST 684 685DEF("k", HAS_ARG, QEMU_OPTION_k, 686 "-k language use keyboard layout (for example 'fr' for French)\n", 687 QEMU_ARCH_ALL) 688SRST 689``-k language`` 690 Use keyboard layout language (for example ``fr`` for French). This 691 option is only needed where it is not easy to get raw PC keycodes 692 (e.g. on Macs, with some X11 servers or with a VNC or curses 693 display). You don't normally need to use it on PC/Linux or 694 PC/Windows hosts. 695 696 The available layouts are: 697 698 :: 699 700 ar de-ch es fo fr-ca hu ja mk no pt-br sv 701 da en-gb et fr fr-ch is lt nl pl ru th 702 de en-us fi fr-be hr it lv nl-be pt sl tr 703 704 The default is ``en-us``. 705ERST 706 707 708HXCOMM Deprecated by -audiodev 709DEF("audio-help", 0, QEMU_OPTION_audio_help, 710 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 711 QEMU_ARCH_ALL) 712SRST 713``-audio-help`` 714 Will show the -audiodev equivalent of the currently specified 715 (deprecated) environment variables. 716ERST 717 718DEF("audio", HAS_ARG, QEMU_OPTION_audio, 719 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 720 " specifies the audio backend and device to use;\n" 721 " apart from 'model', options are the same as for -audiodev.\n" 722 " use '-audio model=help' to show possible devices.\n", 723 QEMU_ARCH_ALL) 724SRST 725``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 726 This option is a shortcut for configuring both the guest audio 727 hardware and the host audio backend in one go. 728 The driver option is the same as with the corresponding ``-audiodev`` option below. 729 The guest hardware model can be set with ``model=modelname``. 730 731 Use ``driver=help`` to list the available drivers, 732 and ``model=help`` to list the available device types. 733 734 The following two example do exactly the same, to show how ``-audio`` 735 can be used to shorten the command line length: 736 737 .. parsed-literal:: 738 739 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 740 |qemu_system| -audio pa,model=sb16 741ERST 742 743DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 744 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 745 " specifies the audio backend to use\n" 746 " Use ``-audiodev help`` to list the available drivers\n" 747 " id= identifier of the backend\n" 748 " timer-period= timer period in microseconds\n" 749 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 750 " in|out.fixed-settings= use fixed settings for host audio\n" 751 " in|out.frequency= frequency to use with fixed settings\n" 752 " in|out.channels= number of channels to use with fixed settings\n" 753 " in|out.format= sample format to use with fixed settings\n" 754 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 755 " in|out.voices= number of voices to use\n" 756 " in|out.buffer-length= length of buffer in microseconds\n" 757 "-audiodev none,id=id,[,prop[=value][,...]]\n" 758 " dummy driver that discards all output\n" 759#ifdef CONFIG_AUDIO_ALSA 760 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 761 " in|out.dev= name of the audio device to use\n" 762 " in|out.period-length= length of period in microseconds\n" 763 " in|out.try-poll= attempt to use poll mode\n" 764 " threshold= threshold (in microseconds) when playback starts\n" 765#endif 766#ifdef CONFIG_AUDIO_COREAUDIO 767 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 768 " in|out.buffer-count= number of buffers\n" 769#endif 770#ifdef CONFIG_AUDIO_DSOUND 771 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 772 " latency= add extra latency to playback in microseconds\n" 773#endif 774#ifdef CONFIG_AUDIO_OSS 775 "-audiodev oss,id=id[,prop[=value][,...]]\n" 776 " in|out.dev= path of the audio device to use\n" 777 " in|out.buffer-count= number of buffers\n" 778 " in|out.try-poll= attempt to use poll mode\n" 779 " try-mmap= try using memory mapped access\n" 780 " exclusive= open device in exclusive mode\n" 781 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 782#endif 783#ifdef CONFIG_AUDIO_PA 784 "-audiodev pa,id=id[,prop[=value][,...]]\n" 785 " server= PulseAudio server address\n" 786 " in|out.name= source/sink device name\n" 787 " in|out.latency= desired latency in microseconds\n" 788#endif 789#ifdef CONFIG_AUDIO_SDL 790 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 791 " in|out.buffer-count= number of buffers\n" 792#endif 793#ifdef CONFIG_AUDIO_SNDIO 794 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 795#endif 796#ifdef CONFIG_SPICE 797 "-audiodev spice,id=id[,prop[=value][,...]]\n" 798#endif 799#ifdef CONFIG_DBUS_DISPLAY 800 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 801#endif 802 "-audiodev wav,id=id[,prop[=value][,...]]\n" 803 " path= path of wav file to record\n", 804 QEMU_ARCH_ALL) 805SRST 806``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 807 Adds a new audio backend driver identified by id. There are global 808 and driver specific properties. Some values can be set differently 809 for input and output, they're marked with ``in|out.``. You can set 810 the input's property with ``in.prop`` and the output's property with 811 ``out.prop``. For example: 812 813 :: 814 815 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 816 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 817 818 NOTE: parameter validation is known to be incomplete, in many cases 819 specifying an invalid option causes QEMU to print an error message 820 and continue emulation without sound. 821 822 Valid global options are: 823 824 ``id=identifier`` 825 Identifies the audio backend. 826 827 ``timer-period=period`` 828 Sets the timer period used by the audio subsystem in 829 microseconds. Default is 10000 (10 ms). 830 831 ``in|out.mixing-engine=on|off`` 832 Use QEMU's mixing engine to mix all streams inside QEMU and 833 convert audio formats when not supported by the backend. When 834 off, fixed-settings must be off too. Note that disabling this 835 option means that the selected backend must support multiple 836 streams and the audio formats used by the virtual cards, 837 otherwise you'll get no sound. It's not recommended to disable 838 this option unless you want to use 5.1 or 7.1 audio, as mixing 839 engine only supports mono and stereo audio. Default is on. 840 841 ``in|out.fixed-settings=on|off`` 842 Use fixed settings for host audio. When off, it will change 843 based on how the guest opens the sound card. In this case you 844 must not specify frequency, channels or format. Default is on. 845 846 ``in|out.frequency=frequency`` 847 Specify the frequency to use when using fixed-settings. Default 848 is 44100Hz. 849 850 ``in|out.channels=channels`` 851 Specify the number of channels to use when using fixed-settings. 852 Default is 2 (stereo). 853 854 ``in|out.format=format`` 855 Specify the sample format to use when using fixed-settings. 856 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 857 ``u32``, ``f32``. Default is ``s16``. 858 859 ``in|out.voices=voices`` 860 Specify the number of voices to use. Default is 1. 861 862 ``in|out.buffer-length=usecs`` 863 Sets the size of the buffer in microseconds. 864 865``-audiodev none,id=id[,prop[=value][,...]]`` 866 Creates a dummy backend that discards all outputs. This backend has 867 no backend specific properties. 868 869``-audiodev alsa,id=id[,prop[=value][,...]]`` 870 Creates backend using the ALSA. This backend is only available on 871 Linux. 872 873 ALSA specific options are: 874 875 ``in|out.dev=device`` 876 Specify the ALSA device to use for input and/or output. Default 877 is ``default``. 878 879 ``in|out.period-length=usecs`` 880 Sets the period length in microseconds. 881 882 ``in|out.try-poll=on|off`` 883 Attempt to use poll mode with the device. Default is on. 884 885 ``threshold=threshold`` 886 Threshold (in microseconds) when playback starts. Default is 0. 887 888``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 889 Creates a backend using Apple's Core Audio. This backend is only 890 available on Mac OS and only supports playback. 891 892 Core Audio specific options are: 893 894 ``in|out.buffer-count=count`` 895 Sets the count of the buffers. 896 897``-audiodev dsound,id=id[,prop[=value][,...]]`` 898 Creates a backend using Microsoft's DirectSound. This backend is 899 only available on Windows and only supports playback. 900 901 DirectSound specific options are: 902 903 ``latency=usecs`` 904 Add extra usecs microseconds latency to playback. Default is 905 10000 (10 ms). 906 907``-audiodev oss,id=id[,prop[=value][,...]]`` 908 Creates a backend using OSS. This backend is available on most 909 Unix-like systems. 910 911 OSS specific options are: 912 913 ``in|out.dev=device`` 914 Specify the file name of the OSS device to use. Default is 915 ``/dev/dsp``. 916 917 ``in|out.buffer-count=count`` 918 Sets the count of the buffers. 919 920 ``in|out.try-poll=on|of`` 921 Attempt to use poll mode with the device. Default is on. 922 923 ``try-mmap=on|off`` 924 Try using memory mapped device access. Default is off. 925 926 ``exclusive=on|off`` 927 Open the device in exclusive mode (vmix won't work in this 928 case). Default is off. 929 930 ``dsp-policy=policy`` 931 Sets the timing policy (between 0 and 10, where smaller number 932 means smaller latency but higher CPU usage). Use -1 to use 933 buffer sizes specified by ``buffer`` and ``buffer-count``. This 934 option is ignored if you do not have OSS 4. Default is 5. 935 936``-audiodev pa,id=id[,prop[=value][,...]]`` 937 Creates a backend using PulseAudio. This backend is available on 938 most systems. 939 940 PulseAudio specific options are: 941 942 ``server=server`` 943 Sets the PulseAudio server to connect to. 944 945 ``in|out.name=sink`` 946 Use the specified source/sink for recording/playback. 947 948 ``in|out.latency=usecs`` 949 Desired latency in microseconds. The PulseAudio server will try 950 to honor this value but actual latencies may be lower or higher. 951 952``-audiodev sdl,id=id[,prop[=value][,...]]`` 953 Creates a backend using SDL. This backend is available on most 954 systems, but you should use your platform's native backend if 955 possible. 956 957 SDL specific options are: 958 959 ``in|out.buffer-count=count`` 960 Sets the count of the buffers. 961 962``-audiodev sndio,id=id[,prop[=value][,...]]`` 963 Creates a backend using SNDIO. This backend is available on 964 OpenBSD and most other Unix-like systems. 965 966 Sndio specific options are: 967 968 ``in|out.dev=device`` 969 Specify the sndio device to use for input and/or output. Default 970 is ``default``. 971 972 ``in|out.latency=usecs`` 973 Sets the desired period length in microseconds. 974 975``-audiodev spice,id=id[,prop[=value][,...]]`` 976 Creates a backend that sends audio through SPICE. This backend 977 requires ``-spice`` and automatically selected in that case, so 978 usually you can ignore this option. This backend has no backend 979 specific properties. 980 981``-audiodev wav,id=id[,prop[=value][,...]]`` 982 Creates a backend that writes audio to a WAV file. 983 984 Backend specific options are: 985 986 ``path=path`` 987 Write recorded audio into the specified file. Default is 988 ``qemu.wav``. 989ERST 990 991DEF("device", HAS_ARG, QEMU_OPTION_device, 992 "-device driver[,prop[=value][,...]]\n" 993 " add device (based on driver)\n" 994 " prop=value,... sets driver properties\n" 995 " use '-device help' to print all possible drivers\n" 996 " use '-device driver,help' to print all possible properties\n", 997 QEMU_ARCH_ALL) 998SRST 999``-device driver[,prop[=value][,...]]`` 1000 Add device driver. prop=value sets driver properties. Valid 1001 properties depend on the driver. To get help on possible drivers and 1002 properties, use ``-device help`` and ``-device driver,help``. 1003 1004 Some drivers are: 1005 1006``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1007 Add an IPMI BMC. This is a simulation of a hardware management 1008 interface processor that normally sits on a system. It provides a 1009 watchdog and the ability to reset and power control the system. You 1010 need to connect this to an IPMI interface to make it useful 1011 1012 The IPMI slave address to use for the BMC. The default is 0x20. This 1013 address is the BMC's address on the I2C network of management 1014 controllers. If you don't know what this means, it is safe to ignore 1015 it. 1016 1017 ``id=id`` 1018 The BMC id for interfaces to use this device. 1019 1020 ``slave_addr=val`` 1021 Define slave address to use for the BMC. The default is 0x20. 1022 1023 ``sdrfile=file`` 1024 file containing raw Sensor Data Records (SDR) data. The default 1025 is none. 1026 1027 ``fruareasize=val`` 1028 size of a Field Replaceable Unit (FRU) area. The default is 1029 1024. 1030 1031 ``frudatafile=file`` 1032 file containing raw Field Replaceable Unit (FRU) inventory data. 1033 The default is none. 1034 1035 ``guid=uuid`` 1036 value for the GUID for the BMC, in standard UUID format. If this 1037 is set, get "Get GUID" command to the BMC will return it. 1038 Otherwise "Get GUID" will return an error. 1039 1040``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1041 Add a connection to an external IPMI BMC simulator. Instead of 1042 locally emulating the BMC like the above item, instead connect to an 1043 external entity that provides the IPMI services. 1044 1045 A connection is made to an external BMC simulator. If you do this, 1046 it is strongly recommended that you use the "reconnect=" chardev 1047 option to reconnect to the simulator if the connection is lost. Note 1048 that if this is not used carefully, it can be a security issue, as 1049 the interface has the ability to send resets, NMIs, and power off 1050 the VM. It's best if QEMU makes a connection to an external 1051 simulator running on a secure port on localhost, so neither the 1052 simulator nor QEMU is exposed to any outside network. 1053 1054 See the "lanserv/README.vm" file in the OpenIPMI library for more 1055 details on the external interface. 1056 1057``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1058 Add a KCS IPMI interface on the ISA bus. This also adds a 1059 corresponding ACPI and SMBIOS entries, if appropriate. 1060 1061 ``bmc=id`` 1062 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1063 above. 1064 1065 ``ioport=val`` 1066 Define the I/O address of the interface. The default is 0xca0 1067 for KCS. 1068 1069 ``irq=val`` 1070 Define the interrupt to use. The default is 5. To disable 1071 interrupts, set this to 0. 1072 1073``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1074 Like the KCS interface, but defines a BT interface. The default port 1075 is 0xe4 and the default interrupt is 5. 1076 1077``-device pci-ipmi-kcs,bmc=id`` 1078 Add a KCS IPMI interface on the PCI bus. 1079 1080 ``bmc=id`` 1081 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1082 1083``-device pci-ipmi-bt,bmc=id`` 1084 Like the KCS interface, but defines a BT interface on the PCI bus. 1085 1086``-device intel-iommu[,option=...]`` 1087 This is only supported by ``-machine q35``, which will enable Intel VT-d 1088 emulation within the guest. It supports below options: 1089 1090 ``intremap=on|off`` (default: auto) 1091 This enables interrupt remapping feature. It's required to enable 1092 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1093 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1094 The default value is "auto", which will be decided by the mode of 1095 kernel-irqchip. 1096 1097 ``caching-mode=on|off`` (default: off) 1098 This enables caching mode for the VT-d emulated device. When 1099 caching-mode is enabled, each guest DMA buffer mapping will generate an 1100 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1101 a synchronous way. It is required for ``-device vfio-pci`` to work 1102 with the VT-d device, because host assigned devices requires to setup 1103 the DMA mapping on the host before guest DMA starts. 1104 1105 ``device-iotlb=on|off`` (default: off) 1106 This enables device-iotlb capability for the emulated VT-d device. So 1107 far virtio/vhost should be the only real user for this parameter, 1108 paired with ats=on configured for the device. 1109 1110 ``aw-bits=39|48`` (default: 39) 1111 This decides the address width of IOVA address space. The address 1112 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1113 4-level IOMMU page tables. 1114 1115 Please also refer to the wiki page for general scenarios of VT-d 1116 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1117 1118ERST 1119 1120DEF("name", HAS_ARG, QEMU_OPTION_name, 1121 "-name string1[,process=string2][,debug-threads=on|off]\n" 1122 " set the name of the guest\n" 1123 " string1 sets the window title and string2 the process name\n" 1124 " When debug-threads is enabled, individual threads are given a separate name\n" 1125 " NOTE: The thread names are for debugging and not a stable API.\n", 1126 QEMU_ARCH_ALL) 1127SRST 1128``-name name`` 1129 Sets the name of the guest. This name will be displayed in the SDL 1130 window caption. The name will also be used for the VNC server. Also 1131 optionally set the top visible process name in Linux. Naming of 1132 individual threads can also be enabled on Linux to aid debugging. 1133ERST 1134 1135DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1136 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1137 " specify machine UUID\n", QEMU_ARCH_ALL) 1138SRST 1139``-uuid uuid`` 1140 Set system UUID. 1141ERST 1142 1143DEFHEADING() 1144 1145DEFHEADING(Block device options:) 1146 1147SRST 1148The QEMU block device handling options have a long history and 1149have gone through several iterations as the feature set and complexity 1150of the block layer have grown. Many online guides to QEMU often 1151reference older and deprecated options, which can lead to confusion. 1152 1153The most explicit way to describe disks is to use a combination of 1154``-device`` to specify the hardware device and ``-blockdev`` to 1155describe the backend. The device defines what the guest sees and the 1156backend describes how QEMU handles the data. It is the only guaranteed 1157stable interface for describing block devices and as such is 1158recommended for management tools and scripting. 1159 1160The ``-drive`` option combines the device and backend into a single 1161command line option which is a more human friendly. There is however no 1162interface stability guarantee although some older board models still 1163need updating to work with the modern blockdev forms. 1164 1165Older options like ``-hda`` are essentially macros which expand into 1166``-drive`` options for various drive interfaces. The original forms 1167bake in a lot of assumptions from the days when QEMU was emulating a 1168legacy PC, they are not recommended for modern configurations. 1169 1170ERST 1171 1172DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1173 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1174DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1175SRST 1176``-fda file`` 1177 \ 1178``-fdb file`` 1179 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1180 the System Emulation Users Guide). 1181ERST 1182 1183DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1184 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1185DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1186DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1187 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1188DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1189SRST 1190``-hda file`` 1191 \ 1192``-hdb file`` 1193 \ 1194``-hdc file`` 1195 \ 1196``-hdd file`` 1197 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1198 chapter in the System Emulation Users Guide). 1199ERST 1200 1201DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1202 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1203 QEMU_ARCH_ALL) 1204SRST 1205``-cdrom file`` 1206 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1207 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1208 as filename. 1209ERST 1210 1211DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1212 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1213 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1214 " [,read-only=on|off][,auto-read-only=on|off]\n" 1215 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1216 " [,driver specific parameters...]\n" 1217 " configure a block backend\n", QEMU_ARCH_ALL) 1218SRST 1219``-blockdev option[,option[,option[,...]]]`` 1220 Define a new block driver node. Some of the options apply to all 1221 block drivers, other options are only accepted for a specific block 1222 driver. See below for a list of generic options and options for the 1223 most common block drivers. 1224 1225 Options that expect a reference to another node (e.g. ``file``) can 1226 be given in two ways. Either you specify the node name of an already 1227 existing node (file=node-name), or you define a new node inline, 1228 adding options for the referenced node after a dot 1229 (file.filename=path,file.aio=native). 1230 1231 A block driver node created with ``-blockdev`` can be used for a 1232 guest device by specifying its node name for the ``drive`` property 1233 in a ``-device`` argument that defines a block device. 1234 1235 ``Valid options for any block driver node:`` 1236 ``driver`` 1237 Specifies the block driver to use for the given node. 1238 1239 ``node-name`` 1240 This defines the name of the block driver node by which it 1241 will be referenced later. The name must be unique, i.e. it 1242 must not match the name of a different block driver node, or 1243 (if you use ``-drive`` as well) the ID of a drive. 1244 1245 If no node name is specified, it is automatically generated. 1246 The generated node name is not intended to be predictable 1247 and changes between QEMU invocations. For the top level, an 1248 explicit node name must be specified. 1249 1250 ``read-only`` 1251 Open the node read-only. Guest write attempts will fail. 1252 1253 Note that some block drivers support only read-only access, 1254 either generally or in certain configurations. In this case, 1255 the default value ``read-only=off`` does not work and the 1256 option must be specified explicitly. 1257 1258 ``auto-read-only`` 1259 If ``auto-read-only=on`` is set, QEMU may fall back to 1260 read-only usage even when ``read-only=off`` is requested, or 1261 even switch between modes as needed, e.g. depending on 1262 whether the image file is writable or whether a writing user 1263 is attached to the node. 1264 1265 ``force-share`` 1266 Override the image locking system of QEMU by forcing the 1267 node to utilize weaker shared access for permissions where 1268 it would normally request exclusive access. When there is 1269 the potential for multiple instances to have the same file 1270 open (whether this invocation of QEMU is the first or the 1271 second instance), both instances must permit shared access 1272 for the second instance to succeed at opening the file. 1273 1274 Enabling ``force-share=on`` requires ``read-only=on``. 1275 1276 ``cache.direct`` 1277 The host page cache can be avoided with ``cache.direct=on``. 1278 This will attempt to do disk IO directly to the guest's 1279 memory. QEMU may still perform an internal copy of the data. 1280 1281 ``cache.no-flush`` 1282 In case you don't care about data integrity over host 1283 failures, you can use ``cache.no-flush=on``. This option 1284 tells QEMU that it never needs to write any data to the disk 1285 but can instead keep things in cache. If anything goes 1286 wrong, like your host losing power, the disk storage getting 1287 disconnected accidentally, etc. your image will most 1288 probably be rendered unusable. 1289 1290 ``discard=discard`` 1291 discard is one of "ignore" (or "off") or "unmap" (or "on") 1292 and controls whether ``discard`` (also known as ``trim`` or 1293 ``unmap``) requests are ignored or passed to the filesystem. 1294 Some machine types may not support discard requests. 1295 1296 ``detect-zeroes=detect-zeroes`` 1297 detect-zeroes is "off", "on" or "unmap" and enables the 1298 automatic conversion of plain zero writes by the OS to 1299 driver specific optimized zero write commands. You may even 1300 choose "unmap" if discard is set to "unmap" to allow a zero 1301 write to be converted to an ``unmap`` operation. 1302 1303 ``Driver-specific options for file`` 1304 This is the protocol-level block driver for accessing regular 1305 files. 1306 1307 ``filename`` 1308 The path to the image file in the local filesystem 1309 1310 ``aio`` 1311 Specifies the AIO backend (threads/native/io_uring, 1312 default: threads) 1313 1314 ``locking`` 1315 Specifies whether the image file is protected with Linux OFD 1316 / POSIX locks. The default is to use the Linux Open File 1317 Descriptor API if available, otherwise no lock is applied. 1318 (auto/on/off, default: auto) 1319 1320 Example: 1321 1322 :: 1323 1324 -blockdev driver=file,node-name=disk,filename=disk.img 1325 1326 ``Driver-specific options for raw`` 1327 This is the image format block driver for raw images. It is 1328 usually stacked on top of a protocol level block driver such as 1329 ``file``. 1330 1331 ``file`` 1332 Reference to or definition of the data source block driver 1333 node (e.g. a ``file`` driver node) 1334 1335 Example 1: 1336 1337 :: 1338 1339 -blockdev driver=file,node-name=disk_file,filename=disk.img 1340 -blockdev driver=raw,node-name=disk,file=disk_file 1341 1342 Example 2: 1343 1344 :: 1345 1346 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1347 1348 ``Driver-specific options for qcow2`` 1349 This is the image format block driver for qcow2 images. It is 1350 usually stacked on top of a protocol level block driver such as 1351 ``file``. 1352 1353 ``file`` 1354 Reference to or definition of the data source block driver 1355 node (e.g. a ``file`` driver node) 1356 1357 ``backing`` 1358 Reference to or definition of the backing file block device 1359 (default is taken from the image file). It is allowed to 1360 pass ``null`` here in order to disable the default backing 1361 file. 1362 1363 ``lazy-refcounts`` 1364 Whether to enable the lazy refcounts feature (on/off; 1365 default is taken from the image file) 1366 1367 ``cache-size`` 1368 The maximum total size of the L2 table and refcount block 1369 caches in bytes (default: the sum of l2-cache-size and 1370 refcount-cache-size) 1371 1372 ``l2-cache-size`` 1373 The maximum size of the L2 table cache in bytes (default: if 1374 cache-size is not specified - 32M on Linux platforms, and 8M 1375 on non-Linux platforms; otherwise, as large as possible 1376 within the cache-size, while permitting the requested or the 1377 minimal refcount cache size) 1378 1379 ``refcount-cache-size`` 1380 The maximum size of the refcount block cache in bytes 1381 (default: 4 times the cluster size; or if cache-size is 1382 specified, the part of it which is not used for the L2 1383 cache) 1384 1385 ``cache-clean-interval`` 1386 Clean unused entries in the L2 and refcount caches. The 1387 interval is in seconds. The default value is 600 on 1388 supporting platforms, and 0 on other platforms. Setting it 1389 to 0 disables this feature. 1390 1391 ``pass-discard-request`` 1392 Whether discard requests to the qcow2 device should be 1393 forwarded to the data source (on/off; default: on if 1394 discard=unmap is specified, off otherwise) 1395 1396 ``pass-discard-snapshot`` 1397 Whether discard requests for the data source should be 1398 issued when a snapshot operation (e.g. deleting a snapshot) 1399 frees clusters in the qcow2 file (on/off; default: on) 1400 1401 ``pass-discard-other`` 1402 Whether discard requests for the data source should be 1403 issued on other occasions where a cluster gets freed 1404 (on/off; default: off) 1405 1406 ``overlap-check`` 1407 Which overlap checks to perform for writes to the image 1408 (none/constant/cached/all; default: cached). For details or 1409 finer granularity control refer to the QAPI documentation of 1410 ``blockdev-add``. 1411 1412 Example 1: 1413 1414 :: 1415 1416 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1417 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1418 1419 Example 2: 1420 1421 :: 1422 1423 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1424 1425 ``Driver-specific options for other drivers`` 1426 Please refer to the QAPI documentation of the ``blockdev-add`` 1427 QMP command. 1428ERST 1429 1430DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1431 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1432 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1433 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1434 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1435 " [,aio=threads|native|io_uring]\n" 1436 " [,readonly=on|off][,copy-on-read=on|off]\n" 1437 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1438 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1439 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1440 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1441 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1442 " [[,iops_size=is]]\n" 1443 " [[,group=g]]\n" 1444 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1445SRST 1446``-drive option[,option[,option[,...]]]`` 1447 Define a new drive. This includes creating a block driver node (the 1448 backend) as well as a guest device, and is mostly a shortcut for 1449 defining the corresponding ``-blockdev`` and ``-device`` options. 1450 1451 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1452 In addition, it knows the following options: 1453 1454 ``file=file`` 1455 This option defines which disk image (see the :ref:`disk images` 1456 chapter in the System Emulation Users Guide) to use with this drive. 1457 If the filename contains comma, you must double it (for instance, 1458 "file=my,,file" to use file "my,file"). 1459 1460 Special files such as iSCSI devices can be specified using 1461 protocol specific URLs. See the section for "Device URL Syntax" 1462 for more information. 1463 1464 ``if=interface`` 1465 This option defines on which type on interface the drive is 1466 connected. Available types are: ide, scsi, sd, mtd, floppy, 1467 pflash, virtio, none. 1468 1469 ``bus=bus,unit=unit`` 1470 These options define where is connected the drive by defining 1471 the bus number and the unit id. 1472 1473 ``index=index`` 1474 This option defines where the drive is connected by using an 1475 index in the list of available connectors of a given interface 1476 type. 1477 1478 ``media=media`` 1479 This option defines the type of the media: disk or cdrom. 1480 1481 ``snapshot=snapshot`` 1482 snapshot is "on" or "off" and controls snapshot mode for the 1483 given drive (see ``-snapshot``). 1484 1485 ``cache=cache`` 1486 cache is "none", "writeback", "unsafe", "directsync" or 1487 "writethrough" and controls how the host cache is used to access 1488 block data. This is a shortcut that sets the ``cache.direct`` 1489 and ``cache.no-flush`` options (as in ``-blockdev``), and 1490 additionally ``cache.writeback``, which provides a default for 1491 the ``write-cache`` option of block guest devices (as in 1492 ``-device``). The modes correspond to the following settings: 1493 1494 ============= =============== ============ ============== 1495 \ cache.writeback cache.direct cache.no-flush 1496 ============= =============== ============ ============== 1497 writeback on off off 1498 none on on off 1499 writethrough off off off 1500 directsync off on off 1501 unsafe on off on 1502 ============= =============== ============ ============== 1503 1504 The default mode is ``cache=writeback``. 1505 1506 ``aio=aio`` 1507 aio is "threads", "native", or "io_uring" and selects between pthread 1508 based disk I/O, native Linux AIO, or Linux io_uring API. 1509 1510 ``format=format`` 1511 Specify which disk format will be used rather than detecting the 1512 format. Can be used to specify format=raw to avoid interpreting 1513 an untrusted format header. 1514 1515 ``werror=action,rerror=action`` 1516 Specify which action to take on write and read errors. Valid 1517 actions are: "ignore" (ignore the error and try to continue), 1518 "stop" (pause QEMU), "report" (report the error to the guest), 1519 "enospc" (pause QEMU only if the host disk is full; report the 1520 error to the guest otherwise). The default setting is 1521 ``werror=enospc`` and ``rerror=report``. 1522 1523 ``copy-on-read=copy-on-read`` 1524 copy-on-read is "on" or "off" and enables whether to copy read 1525 backing file sectors into the image file. 1526 1527 ``bps=b,bps_rd=r,bps_wr=w`` 1528 Specify bandwidth throttling limits in bytes per second, either 1529 for all request types or for reads or writes only. Small values 1530 can lead to timeouts or hangs inside the guest. A safe minimum 1531 for disks is 2 MB/s. 1532 1533 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1534 Specify bursts in bytes per second, either for all request types 1535 or for reads or writes only. Bursts allow the guest I/O to spike 1536 above the limit temporarily. 1537 1538 ``iops=i,iops_rd=r,iops_wr=w`` 1539 Specify request rate limits in requests per second, either for 1540 all request types or for reads or writes only. 1541 1542 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1543 Specify bursts in requests per second, either for all request 1544 types or for reads or writes only. Bursts allow the guest I/O to 1545 spike above the limit temporarily. 1546 1547 ``iops_size=is`` 1548 Let every is bytes of a request count as a new request for iops 1549 throttling purposes. Use this option to prevent guests from 1550 circumventing iops limits by sending fewer but larger requests. 1551 1552 ``group=g`` 1553 Join a throttling quota group with given name g. All drives that 1554 are members of the same group are accounted for together. Use 1555 this option to prevent guests from circumventing throttling 1556 limits by using many small disks instead of a single larger 1557 disk. 1558 1559 By default, the ``cache.writeback=on`` mode is used. It will report 1560 data writes as completed as soon as the data is present in the host 1561 page cache. This is safe as long as your guest OS makes sure to 1562 correctly flush disk caches where needed. If your guest OS does not 1563 handle volatile disk write caches correctly and your host crashes or 1564 loses power, then the guest may experience data corruption. 1565 1566 For such guests, you should consider using ``cache.writeback=off``. 1567 This means that the host page cache will be used to read and write 1568 data, but write notification will be sent to the guest only after 1569 QEMU has made sure to flush each write to the disk. Be aware that 1570 this has a major impact on performance. 1571 1572 When using the ``-snapshot`` option, unsafe caching is always used. 1573 1574 Copy-on-read avoids accessing the same backing file sectors 1575 repeatedly and is useful when the backing file is over a slow 1576 network. By default copy-on-read is off. 1577 1578 Instead of ``-cdrom`` you can use: 1579 1580 .. parsed-literal:: 1581 1582 |qemu_system| -drive file=file,index=2,media=cdrom 1583 1584 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1585 1586 .. parsed-literal:: 1587 1588 |qemu_system| -drive file=file,index=0,media=disk 1589 |qemu_system| -drive file=file,index=1,media=disk 1590 |qemu_system| -drive file=file,index=2,media=disk 1591 |qemu_system| -drive file=file,index=3,media=disk 1592 1593 You can open an image using pre-opened file descriptors from an fd 1594 set: 1595 1596 .. parsed-literal:: 1597 1598 |qemu_system| \\ 1599 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1600 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1601 -drive file=/dev/fdset/2,index=0,media=disk 1602 1603 You can connect a CDROM to the slave of ide0: 1604 1605 .. parsed-literal:: 1606 1607 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1608 1609 If you don't specify the "file=" argument, you define an empty 1610 drive: 1611 1612 .. parsed-literal:: 1613 1614 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1615 1616 Instead of ``-fda``, ``-fdb``, you can use: 1617 1618 .. parsed-literal:: 1619 1620 |qemu_system_x86| -drive file=file,index=0,if=floppy 1621 |qemu_system_x86| -drive file=file,index=1,if=floppy 1622 1623 By default, interface is "ide" and index is automatically 1624 incremented: 1625 1626 .. parsed-literal:: 1627 1628 |qemu_system_x86| -drive file=a -drive file=b 1629 1630 is interpreted like: 1631 1632 .. parsed-literal:: 1633 1634 |qemu_system_x86| -hda a -hdb b 1635ERST 1636 1637DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1638 "-mtdblock file use 'file' as on-board Flash memory image\n", 1639 QEMU_ARCH_ALL) 1640SRST 1641``-mtdblock file`` 1642 Use file as on-board Flash memory image. 1643ERST 1644 1645DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1646 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1647SRST 1648``-sd file`` 1649 Use file as SecureDigital card image. 1650ERST 1651 1652DEF("snapshot", 0, QEMU_OPTION_snapshot, 1653 "-snapshot write to temporary files instead of disk image files\n", 1654 QEMU_ARCH_ALL) 1655SRST 1656``-snapshot`` 1657 Write to temporary files instead of disk image files. In this case, 1658 the raw disk image you use is not written back. You can however 1659 force the write back by pressing C-a s (see the :ref:`disk images` 1660 chapter in the System Emulation Users Guide). 1661 1662 .. warning:: 1663 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1664 to manually create snapshot images to attach to your blockdev). 1665 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1666 can use the 'snapshot' property on your drive declarations 1667 instead of this global option. 1668 1669ERST 1670 1671DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1672 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1673 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1674 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1675 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1676 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1677 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1678 " [[,throttling.iops-size=is]]\n" 1679 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1680 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1681 "-fsdev synth,id=id\n", 1682 QEMU_ARCH_ALL) 1683 1684SRST 1685``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1686 \ 1687``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1688 \ 1689``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1690 \ 1691``-fsdev synth,id=id[,readonly=on]`` 1692 Define a new file system device. Valid options are: 1693 1694 ``local`` 1695 Accesses to the filesystem are done by QEMU. 1696 1697 ``proxy`` 1698 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1699 1700 ``synth`` 1701 Synthetic filesystem, only used by QTests. 1702 1703 ``id=id`` 1704 Specifies identifier for this device. 1705 1706 ``path=path`` 1707 Specifies the export path for the file system device. Files 1708 under this path will be available to the 9p client on the guest. 1709 1710 ``security_model=security_model`` 1711 Specifies the security model to be used for this export path. 1712 Supported security models are "passthrough", "mapped-xattr", 1713 "mapped-file" and "none". In "passthrough" security model, files 1714 are stored using the same credentials as they are created on the 1715 guest. This requires QEMU to run as root. In "mapped-xattr" 1716 security model, some of the file attributes like uid, gid, mode 1717 bits and link target are stored as file attributes. For 1718 "mapped-file" these attributes are stored in the hidden 1719 .virtfs\_metadata directory. Directories exported by this 1720 security model cannot interact with other unix tools. "none" 1721 security model is same as passthrough except the sever won't 1722 report failures if it fails to set file attributes like 1723 ownership. Security model is mandatory only for local fsdriver. 1724 Other fsdrivers (like proxy) don't take security model as a 1725 parameter. 1726 1727 ``writeout=writeout`` 1728 This is an optional argument. The only supported value is 1729 "immediate". This means that host page cache will be used to 1730 read and write data but write notification will be sent to the 1731 guest only when the data has been reported as written by the 1732 storage subsystem. 1733 1734 ``readonly=on`` 1735 Enables exporting 9p share as a readonly mount for guests. By 1736 default read-write access is given. 1737 1738 ``socket=socket`` 1739 Enables proxy filesystem driver to use passed socket file for 1740 communicating with virtfs-proxy-helper(1). 1741 1742 ``sock_fd=sock_fd`` 1743 Enables proxy filesystem driver to use passed socket descriptor 1744 for communicating with virtfs-proxy-helper(1). Usually a helper 1745 like libvirt will create socketpair and pass one of the fds as 1746 sock\_fd. 1747 1748 ``fmode=fmode`` 1749 Specifies the default mode for newly created files on the host. 1750 Works only with security models "mapped-xattr" and 1751 "mapped-file". 1752 1753 ``dmode=dmode`` 1754 Specifies the default mode for newly created directories on the 1755 host. Works only with security models "mapped-xattr" and 1756 "mapped-file". 1757 1758 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1759 Specify bandwidth throttling limits in bytes per second, either 1760 for all request types or for reads or writes only. 1761 1762 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1763 Specify bursts in bytes per second, either for all request types 1764 or for reads or writes only. Bursts allow the guest I/O to spike 1765 above the limit temporarily. 1766 1767 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1768 Specify request rate limits in requests per second, either for 1769 all request types or for reads or writes only. 1770 1771 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1772 Specify bursts in requests per second, either for all request 1773 types or for reads or writes only. Bursts allow the guest I/O to 1774 spike above the limit temporarily. 1775 1776 ``throttling.iops-size=is`` 1777 Let every is bytes of a request count as a new request for iops 1778 throttling purposes. 1779 1780 -fsdev option is used along with -device driver "virtio-9p-...". 1781 1782``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1783 Options for virtio-9p-... driver are: 1784 1785 ``type`` 1786 Specifies the variant to be used. Supported values are "pci", 1787 "ccw" or "device", depending on the machine type. 1788 1789 ``fsdev=id`` 1790 Specifies the id value specified along with -fsdev option. 1791 1792 ``mount_tag=mount_tag`` 1793 Specifies the tag name to be used by the guest to mount this 1794 export point. 1795ERST 1796 1797DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1798 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1799 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1800 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1801 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1802 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1803 QEMU_ARCH_ALL) 1804 1805SRST 1806``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1807 \ 1808``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1809 \ 1810``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1811 \ 1812``-virtfs synth,mount_tag=mount_tag`` 1813 Define a new virtual filesystem device and expose it to the guest using 1814 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1815 directory on host is made directly accessible by guest as a pass-through 1816 file system by using the 9P network protocol for communication between 1817 host and guests, if desired even accessible, shared by several guests 1818 simultaneously. 1819 1820 Note that ``-virtfs`` is actually just a convenience shortcut for its 1821 generalized form ``-fsdev -device virtio-9p-pci``. 1822 1823 The general form of pass-through file system options are: 1824 1825 ``local`` 1826 Accesses to the filesystem are done by QEMU. 1827 1828 ``proxy`` 1829 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1830 1831 ``synth`` 1832 Synthetic filesystem, only used by QTests. 1833 1834 ``id=id`` 1835 Specifies identifier for the filesystem device 1836 1837 ``path=path`` 1838 Specifies the export path for the file system device. Files 1839 under this path will be available to the 9p client on the guest. 1840 1841 ``security_model=security_model`` 1842 Specifies the security model to be used for this export path. 1843 Supported security models are "passthrough", "mapped-xattr", 1844 "mapped-file" and "none". In "passthrough" security model, files 1845 are stored using the same credentials as they are created on the 1846 guest. This requires QEMU to run as root. In "mapped-xattr" 1847 security model, some of the file attributes like uid, gid, mode 1848 bits and link target are stored as file attributes. For 1849 "mapped-file" these attributes are stored in the hidden 1850 .virtfs\_metadata directory. Directories exported by this 1851 security model cannot interact with other unix tools. "none" 1852 security model is same as passthrough except the sever won't 1853 report failures if it fails to set file attributes like 1854 ownership. Security model is mandatory only for local fsdriver. 1855 Other fsdrivers (like proxy) don't take security model as a 1856 parameter. 1857 1858 ``writeout=writeout`` 1859 This is an optional argument. The only supported value is 1860 "immediate". This means that host page cache will be used to 1861 read and write data but write notification will be sent to the 1862 guest only when the data has been reported as written by the 1863 storage subsystem. 1864 1865 ``readonly=on`` 1866 Enables exporting 9p share as a readonly mount for guests. By 1867 default read-write access is given. 1868 1869 ``socket=socket`` 1870 Enables proxy filesystem driver to use passed socket file for 1871 communicating with virtfs-proxy-helper(1). Usually a helper like 1872 libvirt will create socketpair and pass one of the fds as 1873 sock\_fd. 1874 1875 ``sock_fd`` 1876 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1877 socket descriptor for interfacing with virtfs-proxy-helper(1). 1878 1879 ``fmode=fmode`` 1880 Specifies the default mode for newly created files on the host. 1881 Works only with security models "mapped-xattr" and 1882 "mapped-file". 1883 1884 ``dmode=dmode`` 1885 Specifies the default mode for newly created directories on the 1886 host. Works only with security models "mapped-xattr" and 1887 "mapped-file". 1888 1889 ``mount_tag=mount_tag`` 1890 Specifies the tag name to be used by the guest to mount this 1891 export point. 1892 1893 ``multidevs=multidevs`` 1894 Specifies how to deal with multiple devices being shared with a 1895 9p export. Supported behaviours are either "remap", "forbid" or 1896 "warn". The latter is the default behaviour on which virtfs 9p 1897 expects only one device to be shared with the same export, and 1898 if more than one device is shared and accessed via the same 9p 1899 export then only a warning message is logged (once) by qemu on 1900 host side. In order to avoid file ID collisions on guest you 1901 should either create a separate virtfs export for each device to 1902 be shared with guests (recommended way) or you might use "remap" 1903 instead which allows you to share multiple devices with only one 1904 export instead, which is achieved by remapping the original 1905 inode numbers from host to guest in a way that would prevent 1906 such collisions. Remapping inodes in such use cases is required 1907 because the original device IDs from host are never passed and 1908 exposed on guest. Instead all files of an export shared with 1909 virtfs always share the same device id on guest. So two files 1910 with identical inode numbers but from actually different devices 1911 on host would otherwise cause a file ID collision and hence 1912 potential misbehaviours on guest. "forbid" on the other hand 1913 assumes like "warn" that only one device is shared by the same 1914 export, however it will not only log a warning message but also 1915 deny access to additional devices on guest. Note though that 1916 "forbid" does currently not block all possible file access 1917 operations (e.g. readdir() would still return entries from other 1918 devices). 1919ERST 1920 1921DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1922 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1923 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1924 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1925 " [,timeout=timeout]\n" 1926 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1927 1928SRST 1929``-iscsi`` 1930 Configure iSCSI session parameters. 1931ERST 1932 1933DEFHEADING() 1934 1935DEFHEADING(USB convenience options:) 1936 1937DEF("usb", 0, QEMU_OPTION_usb, 1938 "-usb enable on-board USB host controller (if not enabled by default)\n", 1939 QEMU_ARCH_ALL) 1940SRST 1941``-usb`` 1942 Enable USB emulation on machine types with an on-board USB host 1943 controller (if not enabled by default). Note that on-board USB host 1944 controllers may not support USB 3.0. In this case 1945 ``-device qemu-xhci`` can be used instead on machines with PCI. 1946ERST 1947 1948DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1949 "-usbdevice name add the host or guest USB device 'name'\n", 1950 QEMU_ARCH_ALL) 1951SRST 1952``-usbdevice devname`` 1953 Add the USB device devname, and enable an on-board USB controller 1954 if possible and necessary (just like it can be done via 1955 ``-machine usb=on``). Note that this option is mainly intended for 1956 the user's convenience only. More fine-grained control can be 1957 achieved by selecting a USB host controller (if necessary) and the 1958 desired USB device via the ``-device`` option instead. For example, 1959 instead of using ``-usbdevice mouse`` it is possible to use 1960 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1961 to a USB 3.0 controller instead (at least on machines that support 1962 PCI and do not have an USB controller enabled by default yet). 1963 For more details, see the chapter about 1964 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1965 Possible devices for devname are: 1966 1967 ``braille`` 1968 Braille device. This will use BrlAPI to display the braille 1969 output on a real or fake device (i.e. it also creates a 1970 corresponding ``braille`` chardev automatically beside the 1971 ``usb-braille`` USB device). 1972 1973 ``keyboard`` 1974 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1975 1976 ``mouse`` 1977 Virtual Mouse. This will override the PS/2 mouse emulation when 1978 activated. 1979 1980 ``tablet`` 1981 Pointer device that uses absolute coordinates (like a 1982 touchscreen). This means QEMU is able to report the mouse 1983 position without having to grab the mouse. Also overrides the 1984 PS/2 mouse emulation when activated. 1985 1986 ``wacom-tablet`` 1987 Wacom PenPartner USB tablet. 1988 1989 1990ERST 1991 1992DEFHEADING() 1993 1994DEFHEADING(Display options:) 1995 1996DEF("display", HAS_ARG, QEMU_OPTION_display, 1997#if defined(CONFIG_SPICE) 1998 "-display spice-app[,gl=on|off]\n" 1999#endif 2000#if defined(CONFIG_SDL) 2001 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2002 " [,window-close=on|off]\n" 2003#endif 2004#if defined(CONFIG_GTK) 2005 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2006 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2007 " [,show-menubar=on|off]\n" 2008#endif 2009#if defined(CONFIG_VNC) 2010 "-display vnc=<display>[,<optargs>]\n" 2011#endif 2012#if defined(CONFIG_CURSES) 2013 "-display curses[,charset=<encoding>]\n" 2014#endif 2015#if defined(CONFIG_COCOA) 2016 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2017#endif 2018#if defined(CONFIG_OPENGL) 2019 "-display egl-headless[,rendernode=<file>]\n" 2020#endif 2021#if defined(CONFIG_DBUS_DISPLAY) 2022 "-display dbus[,addr=<dbusaddr>]\n" 2023 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2024#endif 2025#if defined(CONFIG_COCOA) 2026 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 2027#endif 2028 "-display none\n" 2029 " select display backend type\n" 2030 " The default display is equivalent to\n " 2031#if defined(CONFIG_GTK) 2032 "\"-display gtk\"\n" 2033#elif defined(CONFIG_SDL) 2034 "\"-display sdl\"\n" 2035#elif defined(CONFIG_COCOA) 2036 "\"-display cocoa\"\n" 2037#elif defined(CONFIG_VNC) 2038 "\"-vnc localhost:0,to=99,id=default\"\n" 2039#else 2040 "\"-display none\"\n" 2041#endif 2042 , QEMU_ARCH_ALL) 2043SRST 2044``-display type`` 2045 Select type of display to use. Use ``-display help`` to list the available 2046 display types. Valid values for type are 2047 2048 ``spice-app[,gl=on|off]`` 2049 Start QEMU as a Spice server and launch the default Spice client 2050 application. The Spice server will redirect the serial consoles 2051 and QEMU monitors. (Since 4.0) 2052 2053 ``dbus`` 2054 Export the display over D-Bus interfaces. (Since 7.0) 2055 2056 The connection is registered with the "org.qemu" name (and queued when 2057 already owned). 2058 2059 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2060 2061 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2062 2063 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2064 will share framebuffers with DMABUF file descriptors). 2065 2066 ``sdl`` 2067 Display video output via SDL (usually in a separate graphics 2068 window; see the SDL documentation for other possibilities). 2069 Valid parameters are: 2070 2071 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2072 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2073 either ``lshift-lctrl-lalt`` or ``rctrl``. 2074 2075 ``gl=on|off|core|es`` : Use OpenGL for displaying 2076 2077 ``show-cursor=on|off`` : Force showing the mouse cursor 2078 2079 ``window-close=on|off`` : Allow to quit qemu with window close button 2080 2081 ``gtk`` 2082 Display video output in a GTK window. This interface provides 2083 drop-down menus and other UI elements to configure and control 2084 the VM during runtime. Valid parameters are: 2085 2086 ``full-screen=on|off`` : Start in fullscreen mode 2087 2088 ``gl=on|off`` : Use OpenGL for displaying 2089 2090 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2091 2092 ``show-tabs=on|off`` : Display the tab bar for switching between the 2093 various graphical interfaces (e.g. VGA and 2094 virtual console character devices) by default. 2095 2096 ``show-cursor=on|off`` : Force showing the mouse cursor 2097 2098 ``window-close=on|off`` : Allow to quit qemu with window close button 2099 2100 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2101 2102 ``curses[,charset=<encoding>]`` 2103 Display video output via curses. For graphics device models 2104 which support a text mode, QEMU can display this output using a 2105 curses/ncurses interface. Nothing is displayed when the graphics 2106 device is in graphical mode or if the graphics device does not 2107 support a text mode. Generally only the VGA device models 2108 support text mode. The font charset used by the guest can be 2109 specified with the ``charset`` option, for example 2110 ``charset=CP850`` for IBM CP850 encoding. The default is 2111 ``CP437``. 2112 2113 ``cocoa`` 2114 Display video output in a Cocoa window. Mac only. This interface 2115 provides drop-down menus and other UI elements to configure and 2116 control the VM during runtime. Valid parameters are: 2117 2118 ``show-cursor=on|off`` : Force showing the mouse cursor 2119 2120 ``left-command-key=on|off`` : Disable forwarding left command key to host 2121 2122 ``egl-headless[,rendernode=<file>]`` 2123 Offload all OpenGL operations to a local DRI device. For any 2124 graphical display, this display needs to be paired with either 2125 VNC or SPICE displays. 2126 2127 ``vnc=<display>`` 2128 Start a VNC server on display <display> 2129 2130 ``none`` 2131 Do not display video output. The guest will still see an 2132 emulated graphics card, but its output will not be displayed to 2133 the QEMU user. This option differs from the -nographic option in 2134 that it only affects what is done with video output; -nographic 2135 also changes the destination of the serial and parallel port 2136 data. 2137ERST 2138 2139DEF("nographic", 0, QEMU_OPTION_nographic, 2140 "-nographic disable graphical output and redirect serial I/Os to console\n", 2141 QEMU_ARCH_ALL) 2142SRST 2143``-nographic`` 2144 Normally, if QEMU is compiled with graphical window support, it 2145 displays output such as guest graphics, guest console, and the QEMU 2146 monitor in a window. With this option, you can totally disable 2147 graphical output so that QEMU is a simple command line application. 2148 The emulated serial port is redirected on the console and muxed with 2149 the monitor (unless redirected elsewhere explicitly). Therefore, you 2150 can still use QEMU to debug a Linux kernel with a serial console. 2151 Use C-a h for help on switching between the console and monitor. 2152ERST 2153 2154#ifdef CONFIG_SPICE 2155DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2156 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2157 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2158 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2159 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2160 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2161 " [,tls-ciphers=<list>]\n" 2162 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2163 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2164 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2165 " [,password-secret=<secret-id>]\n" 2166 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2167 " [,jpeg-wan-compression=[auto|never|always]]\n" 2168 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2169 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2170 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2171 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2172 " [,gl=[on|off]][,rendernode=<file>]\n" 2173 " enable spice\n" 2174 " at least one of {port, tls-port} is mandatory\n", 2175 QEMU_ARCH_ALL) 2176#endif 2177SRST 2178``-spice option[,option[,...]]`` 2179 Enable the spice remote desktop protocol. Valid options are 2180 2181 ``port=<nr>`` 2182 Set the TCP port spice is listening on for plaintext channels. 2183 2184 ``addr=<addr>`` 2185 Set the IP address spice is listening on. Default is any 2186 address. 2187 2188 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2189 Force using the specified IP version. 2190 2191 ``password-secret=<secret-id>`` 2192 Set the ID of the ``secret`` object containing the password 2193 you need to authenticate. 2194 2195 ``sasl=on|off`` 2196 Require that the client use SASL to authenticate with the spice. 2197 The exact choice of authentication method used is controlled 2198 from the system / user's SASL configuration file for the 'qemu' 2199 service. This is typically found in /etc/sasl2/qemu.conf. If 2200 running QEMU as an unprivileged user, an environment variable 2201 SASL\_CONF\_PATH can be used to make it search alternate 2202 locations for the service config. While some SASL auth methods 2203 can also provide data encryption (eg GSSAPI), it is recommended 2204 that SASL always be combined with the 'tls' and 'x509' settings 2205 to enable use of SSL and server certificates. This ensures a 2206 data encryption preventing compromise of authentication 2207 credentials. 2208 2209 ``disable-ticketing=on|off`` 2210 Allow client connects without authentication. 2211 2212 ``disable-copy-paste=on|off`` 2213 Disable copy paste between the client and the guest. 2214 2215 ``disable-agent-file-xfer=on|off`` 2216 Disable spice-vdagent based file-xfer between the client and the 2217 guest. 2218 2219 ``tls-port=<nr>`` 2220 Set the TCP port spice is listening on for encrypted channels. 2221 2222 ``x509-dir=<dir>`` 2223 Set the x509 file directory. Expects same filenames as -vnc 2224 $display,x509=$dir 2225 2226 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2227 The x509 file names can also be configured individually. 2228 2229 ``tls-ciphers=<list>`` 2230 Specify which ciphers to use. 2231 2232 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2233 Force specific channel to be used with or without TLS 2234 encryption. The options can be specified multiple times to 2235 configure multiple channels. The special name "default" can be 2236 used to set the default mode. For channels which are not 2237 explicitly forced into one mode the spice client is allowed to 2238 pick tls/plaintext as he pleases. 2239 2240 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2241 Configure image compression (lossless). Default is auto\_glz. 2242 2243 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2244 Configure wan image compression (lossy for slow links). Default 2245 is auto. 2246 2247 ``streaming-video=[off|all|filter]`` 2248 Configure video stream detection. Default is off. 2249 2250 ``agent-mouse=[on|off]`` 2251 Enable/disable passing mouse events via vdagent. Default is on. 2252 2253 ``playback-compression=[on|off]`` 2254 Enable/disable audio stream compression (using celt 0.5.1). 2255 Default is on. 2256 2257 ``seamless-migration=[on|off]`` 2258 Enable/disable spice seamless migration. Default is off. 2259 2260 ``gl=[on|off]`` 2261 Enable/disable OpenGL context. Default is off. 2262 2263 ``rendernode=<file>`` 2264 DRM render node for OpenGL rendering. If not specified, it will 2265 pick the first available. (Since 2.9) 2266ERST 2267 2268DEF("portrait", 0, QEMU_OPTION_portrait, 2269 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2270 QEMU_ARCH_ALL) 2271SRST 2272``-portrait`` 2273 Rotate graphical output 90 deg left (only PXA LCD). 2274ERST 2275 2276DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2277 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2278 QEMU_ARCH_ALL) 2279SRST 2280``-rotate deg`` 2281 Rotate graphical output some deg left (only PXA LCD). 2282ERST 2283 2284DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2285 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2286 " select video card type\n", QEMU_ARCH_ALL) 2287SRST 2288``-vga type`` 2289 Select type of VGA card to emulate. Valid values for type are 2290 2291 ``cirrus`` 2292 Cirrus Logic GD5446 Video card. All Windows versions starting 2293 from Windows 95 should recognize and use this graphic card. For 2294 optimal performances, use 16 bit color depth in the guest and 2295 the host OS. (This card was the default before QEMU 2.2) 2296 2297 ``std`` 2298 Standard VGA card with Bochs VBE extensions. If your guest OS 2299 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2300 you want to use high resolution modes (>= 1280x1024x16) then you 2301 should use this option. (This card is the default since QEMU 2302 2.2) 2303 2304 ``vmware`` 2305 VMWare SVGA-II compatible adapter. Use it if you have 2306 sufficiently recent XFree86/XOrg server or Windows guest with a 2307 driver for this card. 2308 2309 ``qxl`` 2310 QXL paravirtual graphic card. It is VGA compatible (including 2311 VESA 2.0 VBE support). Works best with qxl guest drivers 2312 installed though. Recommended choice when using the spice 2313 protocol. 2314 2315 ``tcx`` 2316 (sun4m only) Sun TCX framebuffer. This is the default 2317 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2318 colour depths at a fixed resolution of 1024x768. 2319 2320 ``cg3`` 2321 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2322 framebuffer for sun4m machines available in both 1024x768 2323 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2324 wishing to run older Solaris versions. 2325 2326 ``virtio`` 2327 Virtio VGA card. 2328 2329 ``none`` 2330 Disable VGA card. 2331ERST 2332 2333DEF("full-screen", 0, QEMU_OPTION_full_screen, 2334 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2335SRST 2336``-full-screen`` 2337 Start in full screen. 2338ERST 2339 2340DEF("g", HAS_ARG, QEMU_OPTION_g , 2341 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2342 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2343SRST 2344``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2345 Set the initial graphical resolution and depth (PPC, SPARC only). 2346 2347 For PPC the default is 800x600x32. 2348 2349 For SPARC with the TCX graphics device, the default is 1024x768x8 2350 with the option of 1024x768x24. For cgthree, the default is 2351 1024x768x8 with the option of 1152x900x8 for people who wish to use 2352 OBP. 2353ERST 2354 2355DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2356 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2357SRST 2358``-vnc display[,option[,option[,...]]]`` 2359 Normally, if QEMU is compiled with graphical window support, it 2360 displays output such as guest graphics, guest console, and the QEMU 2361 monitor in a window. With this option, you can have QEMU listen on 2362 VNC display display and redirect the VGA display over the VNC 2363 session. It is very useful to enable the usb tablet device when 2364 using this option (option ``-device usb-tablet``). When using the 2365 VNC display, you must use the ``-k`` parameter to set the keyboard 2366 layout if you are not using en-us. Valid syntax for the display is 2367 2368 ``to=L`` 2369 With this option, QEMU will try next available VNC displays, 2370 until the number L, if the origianlly defined "-vnc display" is 2371 not available, e.g. port 5900+display is already used by another 2372 application. By default, to=0. 2373 2374 ``host:d`` 2375 TCP connections will only be allowed from host on display d. By 2376 convention the TCP port is 5900+d. Optionally, host can be 2377 omitted in which case the server will accept connections from 2378 any host. 2379 2380 ``unix:path`` 2381 Connections will be allowed over UNIX domain sockets where path 2382 is the location of a unix socket to listen for connections on. 2383 2384 ``none`` 2385 VNC is initialized but not started. The monitor ``change`` 2386 command can be used to later start the VNC server. 2387 2388 Following the display value there may be one or more option flags 2389 separated by commas. Valid options are 2390 2391 ``reverse=on|off`` 2392 Connect to a listening VNC client via a "reverse" connection. 2393 The client is specified by the display. For reverse network 2394 connections (host:d,``reverse``), the d argument is a TCP port 2395 number, not a display number. 2396 2397 ``websocket=on|off`` 2398 Opens an additional TCP listening port dedicated to VNC 2399 Websocket connections. If a bare websocket option is given, the 2400 Websocket port is 5700+display. An alternative port can be 2401 specified with the syntax ``websocket``\ =port. 2402 2403 If host is specified connections will only be allowed from this 2404 host. It is possible to control the websocket listen address 2405 independently, using the syntax ``websocket``\ =host:port. 2406 2407 If no TLS credentials are provided, the websocket connection 2408 runs in unencrypted mode. If TLS credentials are provided, the 2409 websocket connection requires encrypted client connections. 2410 2411 ``password=on|off`` 2412 Require that password based authentication is used for client 2413 connections. 2414 2415 The password must be set separately using the ``set_password`` 2416 command in the :ref:`QEMU monitor`. The 2417 syntax to change your password is: 2418 ``set_password <protocol> <password>`` where <protocol> could be 2419 either "vnc" or "spice". 2420 2421 If you would like to change <protocol> password expiration, you 2422 should use ``expire_password <protocol> <expiration-time>`` 2423 where expiration time could be one of the following options: 2424 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2425 make password expire in 60 seconds, or 1335196800 to make 2426 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2427 this date and time). 2428 2429 You can also use keywords "now" or "never" for the expiration 2430 time to allow <protocol> password to expire immediately or never 2431 expire. 2432 2433 ``password-secret=<secret-id>`` 2434 Require that password based authentication is used for client 2435 connections, using the password provided by the ``secret`` 2436 object identified by ``secret-id``. 2437 2438 ``tls-creds=ID`` 2439 Provides the ID of a set of TLS credentials to use to secure the 2440 VNC server. They will apply to both the normal VNC server socket 2441 and the websocket socket (if enabled). Setting TLS credentials 2442 will cause the VNC server socket to enable the VeNCrypt auth 2443 mechanism. The credentials should have been previously created 2444 using the ``-object tls-creds`` argument. 2445 2446 ``tls-authz=ID`` 2447 Provides the ID of the QAuthZ authorization object against which 2448 the client's x509 distinguished name will validated. This object 2449 is only resolved at time of use, so can be deleted and recreated 2450 on the fly while the VNC server is active. If missing, it will 2451 default to denying access. 2452 2453 ``sasl=on|off`` 2454 Require that the client use SASL to authenticate with the VNC 2455 server. The exact choice of authentication method used is 2456 controlled from the system / user's SASL configuration file for 2457 the 'qemu' service. This is typically found in 2458 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2459 an environment variable SASL\_CONF\_PATH can be used to make it 2460 search alternate locations for the service config. While some 2461 SASL auth methods can also provide data encryption (eg GSSAPI), 2462 it is recommended that SASL always be combined with the 'tls' 2463 and 'x509' settings to enable use of SSL and server 2464 certificates. This ensures a data encryption preventing 2465 compromise of authentication credentials. See the 2466 :ref:`VNC security` section in the System Emulation Users Guide 2467 for details on using SASL authentication. 2468 2469 ``sasl-authz=ID`` 2470 Provides the ID of the QAuthZ authorization object against which 2471 the client's SASL username will validated. This object is only 2472 resolved at time of use, so can be deleted and recreated on the 2473 fly while the VNC server is active. If missing, it will default 2474 to denying access. 2475 2476 ``acl=on|off`` 2477 Legacy method for enabling authorization of clients against the 2478 x509 distinguished name and SASL username. It results in the 2479 creation of two ``authz-list`` objects with IDs of 2480 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2481 objects must be configured with the HMP ACL commands. 2482 2483 This option is deprecated and should no longer be used. The new 2484 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2485 2486 ``lossy=on|off`` 2487 Enable lossy compression methods (gradient, JPEG, ...). If this 2488 option is set, VNC client may receive lossy framebuffer updates 2489 depending on its encoding settings. Enabling this option can 2490 save a lot of bandwidth at the expense of quality. 2491 2492 ``non-adaptive=on|off`` 2493 Disable adaptive encodings. Adaptive encodings are enabled by 2494 default. An adaptive encoding will try to detect frequently 2495 updated screen regions, and send updates in these regions using 2496 a lossy encoding (like JPEG). This can be really helpful to save 2497 bandwidth when playing videos. Disabling adaptive encodings 2498 restores the original static behavior of encodings like Tight. 2499 2500 ``share=[allow-exclusive|force-shared|ignore]`` 2501 Set display sharing policy. 'allow-exclusive' allows clients to 2502 ask for exclusive access. As suggested by the rfb spec this is 2503 implemented by dropping other connections. Connecting multiple 2504 clients in parallel requires all clients asking for a shared 2505 session (vncviewer: -shared switch). This is the default. 2506 'force-shared' disables exclusive client access. Useful for 2507 shared desktop sessions, where you don't want someone forgetting 2508 specify -shared disconnect everybody else. 'ignore' completely 2509 ignores the shared flag and allows everybody connect 2510 unconditionally. Doesn't conform to the rfb spec but is 2511 traditional QEMU behavior. 2512 2513 ``key-delay-ms`` 2514 Set keyboard delay, for key down and key up events, in 2515 milliseconds. Default is 10. Keyboards are low-bandwidth 2516 devices, so this slowdown can help the device and guest to keep 2517 up and not lose events in case events are arriving in bulk. 2518 Possible causes for the latter are flaky network connections, or 2519 scripts for automated testing. 2520 2521 ``audiodev=audiodev`` 2522 Use the specified audiodev when the VNC client requests audio 2523 transmission. When not using an -audiodev argument, this option 2524 must be omitted, otherwise is must be present and specify a 2525 valid audiodev. 2526 2527 ``power-control=on|off`` 2528 Permit the remote client to issue shutdown, reboot or reset power 2529 control requests. 2530ERST 2531 2532ARCHHEADING(, QEMU_ARCH_I386) 2533 2534ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2535 2536DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2537 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2538 QEMU_ARCH_I386) 2539SRST 2540``-win2k-hack`` 2541 Use it when installing Windows 2000 to avoid a disk full bug. After 2542 Windows 2000 is installed, you no longer need this option (this 2543 option slows down the IDE transfers). 2544ERST 2545 2546DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2547 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2548 QEMU_ARCH_I386) 2549SRST 2550``-no-fd-bootchk`` 2551 Disable boot signature checking for floppy disks in BIOS. May be 2552 needed to boot from old floppy disks. 2553ERST 2554 2555DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2556 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2557SRST 2558``-no-acpi`` 2559 Disable ACPI (Advanced Configuration and Power Interface) support. 2560 Use it if your guest OS complains about ACPI problems (PC target 2561 machine only). 2562ERST 2563 2564DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2565 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2566SRST 2567``-no-hpet`` 2568 Disable HPET support. Deprecated, use '-machine hpet=off' instead. 2569ERST 2570 2571DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2572 "-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" 2573 " ACPI table description\n", QEMU_ARCH_I386) 2574SRST 2575``-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]...]`` 2576 Add ACPI table with specified header fields and context from 2577 specified files. For file=, take whole ACPI table from the specified 2578 files, including all ACPI headers (possible overridden by other 2579 options). For data=, only data portion of the table is used, all 2580 header information is specified in the command line. If a SLIC table 2581 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2582 fields will override the same in the RSDT and the FADT (a.k.a. 2583 FACP), in order to ensure the field matches required by the 2584 Microsoft SLIC spec and the ACPI spec. 2585ERST 2586 2587DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2588 "-smbios file=binary\n" 2589 " load SMBIOS entry from binary file\n" 2590 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2591 " [,uefi=on|off]\n" 2592 " specify SMBIOS type 0 fields\n" 2593 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2594 " [,uuid=uuid][,sku=str][,family=str]\n" 2595 " specify SMBIOS type 1 fields\n" 2596 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2597 " [,asset=str][,location=str]\n" 2598 " specify SMBIOS type 2 fields\n" 2599 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2600 " [,sku=str]\n" 2601 " specify SMBIOS type 3 fields\n" 2602 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2603 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2604 " [,processor-id=%d]\n" 2605 " specify SMBIOS type 4 fields\n" 2606 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2607 " specify SMBIOS type 8 fields\n" 2608 "-smbios type=11[,value=str][,path=filename]\n" 2609 " specify SMBIOS type 11 fields\n" 2610 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2611 " [,asset=str][,part=str][,speed=%d]\n" 2612 " specify SMBIOS type 17 fields\n" 2613 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2614 " specify SMBIOS type 41 fields\n", 2615 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2616SRST 2617``-smbios file=binary`` 2618 Load SMBIOS entry from binary file. 2619 2620``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2621 Specify SMBIOS type 0 fields 2622 2623``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2624 Specify SMBIOS type 1 fields 2625 2626``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2627 Specify SMBIOS type 2 fields 2628 2629``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2630 Specify SMBIOS type 3 fields 2631 2632``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2633 Specify SMBIOS type 4 fields 2634 2635``-smbios type=11[,value=str][,path=filename]`` 2636 Specify SMBIOS type 11 fields 2637 2638 This argument can be repeated multiple times, and values are added in the order they are parsed. 2639 Applications intending to use OEM strings data are encouraged to use their application name as 2640 a prefix for the value string. This facilitates passing information for multiple applications 2641 concurrently. 2642 2643 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2644 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2645 2646 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2647 the SMBIOS table in the order in which they appear. 2648 2649 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2650 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2651 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2652 data set, for example, by specifying the serial ID of a block device. 2653 2654 An example passing three strings is 2655 2656 .. parsed-literal:: 2657 2658 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2659 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2660 path=/some/file/with/oemstringsdata.txt 2661 2662 In the guest OS this is visible with the ``dmidecode`` command 2663 2664 .. parsed-literal:: 2665 2666 $ dmidecode -t 11 2667 Handle 0x0E00, DMI type 11, 5 bytes 2668 OEM Strings 2669 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2670 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2671 String 3: myapp:some extra data 2672 2673 2674``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2675 Specify SMBIOS type 17 fields 2676 2677``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2678 Specify SMBIOS type 41 fields 2679 2680 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2681 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2682 position on the PCI bus. 2683 2684 Here is an example of use: 2685 2686 .. parsed-literal:: 2687 2688 -netdev user,id=internet \\ 2689 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2690 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2691 2692 In the guest OS, the device should then appear as ``eno1``: 2693 2694 ..parsed-literal:: 2695 2696 $ ip -brief l 2697 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2698 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2699 2700 Currently, the PCI device has to be attached to the root bus. 2701 2702ERST 2703 2704DEFHEADING() 2705 2706DEFHEADING(Network options:) 2707 2708DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2709#ifdef CONFIG_SLIRP 2710 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2711 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2712 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2713 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2714 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2715#ifndef _WIN32 2716 "[,smb=dir[,smbserver=addr]]\n" 2717#endif 2718 " configure a user mode network backend with ID 'str',\n" 2719 " its DHCP server and optional services\n" 2720#endif 2721#ifdef _WIN32 2722 "-netdev tap,id=str,ifname=name\n" 2723 " configure a host TAP network backend with ID 'str'\n" 2724#else 2725 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2726 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2727 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2728 " [,poll-us=n]\n" 2729 " configure a host TAP network backend with ID 'str'\n" 2730 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2731 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2732 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2733 " to deconfigure it\n" 2734 " use '[down]script=no' to disable script execution\n" 2735 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2736 " configure it\n" 2737 " use 'fd=h' to connect to an already opened TAP interface\n" 2738 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2739 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2740 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2741 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2742 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2743 " use vhost=on to enable experimental in kernel accelerator\n" 2744 " (only has effect for virtio guests which use MSIX)\n" 2745 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2746 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2747 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2748 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2749 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2750 " spent on busy polling for vhost net\n" 2751 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2752 " configure a host TAP network backend with ID 'str' that is\n" 2753 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2754 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2755#endif 2756#ifdef __linux__ 2757 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2758 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2759 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2760 " [,rxcookie=rxcookie][,offset=offset]\n" 2761 " configure a network backend with ID 'str' connected to\n" 2762 " an Ethernet over L2TPv3 pseudowire.\n" 2763 " Linux kernel 3.3+ as well as most routers can talk\n" 2764 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2765 " VM to a router and even VM to Host. It is a nearly-universal\n" 2766 " standard (RFC3931). Note - this implementation uses static\n" 2767 " pre-configured tunnels (same as the Linux kernel).\n" 2768 " use 'src=' to specify source address\n" 2769 " use 'dst=' to specify destination address\n" 2770 " use 'udp=on' to specify udp encapsulation\n" 2771 " use 'srcport=' to specify source udp port\n" 2772 " use 'dstport=' to specify destination udp port\n" 2773 " use 'ipv6=on' to force v6\n" 2774 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2775 " well as a weak security measure\n" 2776 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2777 " use 'txcookie=0x012345678' to specify a txcookie\n" 2778 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2779 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2780 " use 'pincounter=on' to work around broken counter handling in peer\n" 2781 " use 'offset=X' to add an extra offset between header and data\n" 2782#endif 2783 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2784 " configure a network backend to connect to another network\n" 2785 " using a socket connection\n" 2786 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2787 " configure a network backend to connect to a multicast maddr and port\n" 2788 " use 'localaddr=addr' to specify the host address to send packets from\n" 2789 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2790 " configure a network backend to connect to another network\n" 2791 " using an UDP tunnel\n" 2792 "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]\n" 2793 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2794 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2795 " configure a network backend to connect to another network\n" 2796 " using a socket connection in stream mode.\n" 2797 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2798 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2799 " configure a network backend to connect to a multicast maddr and port\n" 2800 " use ``local.host=addr`` to specify the host address to send packets from\n" 2801 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2802 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2803 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2804 " configure a network backend to connect to another network\n" 2805 " using an UDP tunnel\n" 2806#ifdef CONFIG_VDE 2807 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2808 " configure a network backend to connect to port 'n' of a vde switch\n" 2809 " running on host and listening for incoming connections on 'socketpath'.\n" 2810 " Use group 'groupname' and mode 'octalmode' to change default\n" 2811 " ownership and permissions for communication port.\n" 2812#endif 2813#ifdef CONFIG_NETMAP 2814 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2815 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2816 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2817 " netmap device, defaults to '/dev/netmap')\n" 2818#endif 2819#ifdef CONFIG_POSIX 2820 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2821 " configure a vhost-user network, backed by a chardev 'dev'\n" 2822#endif 2823#ifdef __linux__ 2824 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2825 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2826 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2827 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2828#endif 2829#ifdef CONFIG_VMNET 2830 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2831 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2832 " configure a vmnet network backend in host mode with ID 'str',\n" 2833 " isolate this interface from others with 'isolated',\n" 2834 " configure the address range and choose a subnet mask,\n" 2835 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2836 " vmnet-host interfaces within this isolated network\n" 2837 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2838 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2839 " configure a vmnet network backend in shared mode with ID 'str',\n" 2840 " configure the address range and choose a subnet mask,\n" 2841 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2842 " isolate this interface from others with 'isolated'\n" 2843 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2844 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2845 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2846 " isolate this interface from others with 'isolated'\n" 2847#endif 2848 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2849 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2850DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2851 "-nic [tap|bridge|" 2852#ifdef CONFIG_SLIRP 2853 "user|" 2854#endif 2855#ifdef __linux__ 2856 "l2tpv3|" 2857#endif 2858#ifdef CONFIG_VDE 2859 "vde|" 2860#endif 2861#ifdef CONFIG_NETMAP 2862 "netmap|" 2863#endif 2864#ifdef CONFIG_POSIX 2865 "vhost-user|" 2866#endif 2867#ifdef CONFIG_VMNET 2868 "vmnet-host|vmnet-shared|vmnet-bridged|" 2869#endif 2870 "socket][,option][,...][mac=macaddr]\n" 2871 " initialize an on-board / default host NIC (using MAC address\n" 2872 " macaddr) and connect it to the given host network backend\n" 2873 "-nic none use it alone to have zero network devices (the default is to\n" 2874 " provided a 'user' network connection)\n", 2875 QEMU_ARCH_ALL) 2876DEF("net", HAS_ARG, QEMU_OPTION_net, 2877 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2878 " configure or create an on-board (or machine default) NIC and\n" 2879 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2880 "-net [" 2881#ifdef CONFIG_SLIRP 2882 "user|" 2883#endif 2884 "tap|" 2885 "bridge|" 2886#ifdef CONFIG_VDE 2887 "vde|" 2888#endif 2889#ifdef CONFIG_NETMAP 2890 "netmap|" 2891#endif 2892#ifdef CONFIG_VMNET 2893 "vmnet-host|vmnet-shared|vmnet-bridged|" 2894#endif 2895 "socket][,option][,option][,...]\n" 2896 " old way to initialize a host network interface\n" 2897 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2898SRST 2899``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2900 This option is a shortcut for configuring both the on-board 2901 (default) guest NIC hardware and the host network backend in one go. 2902 The host backend options are the same as with the corresponding 2903 ``-netdev`` options below. The guest NIC model can be set with 2904 ``model=modelname``. Use ``model=help`` to list the available device 2905 types. The hardware MAC address can be set with ``mac=macaddr``. 2906 2907 The following two example do exactly the same, to show how ``-nic`` 2908 can be used to shorten the command line length: 2909 2910 .. parsed-literal:: 2911 2912 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2913 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2914 2915``-nic none`` 2916 Indicate that no network devices should be configured. It is used to 2917 override the default configuration (default NIC with "user" host 2918 network backend) which is activated if no other networking options 2919 are provided. 2920 2921``-netdev user,id=id[,option][,option][,...]`` 2922 Configure user mode host network backend which requires no 2923 administrator privilege to run. Valid options are: 2924 2925 ``id=id`` 2926 Assign symbolic name for use in monitor commands. 2927 2928 ``ipv4=on|off and ipv6=on|off`` 2929 Specify that either IPv4 or IPv6 must be enabled. If neither is 2930 specified both protocols are enabled. 2931 2932 ``net=addr[/mask]`` 2933 Set IP network address the guest will see. Optionally specify 2934 the netmask, either in the form a.b.c.d or as number of valid 2935 top-most bits. Default is 10.0.2.0/24. 2936 2937 ``host=addr`` 2938 Specify the guest-visible address of the host. Default is the 2939 2nd IP in the guest network, i.e. x.x.x.2. 2940 2941 ``ipv6-net=addr[/int]`` 2942 Set IPv6 network address the guest will see (default is 2943 fec0::/64). The network prefix is given in the usual hexadecimal 2944 IPv6 address notation. The prefix size is optional, and is given 2945 as the number of valid top-most bits (default is 64). 2946 2947 ``ipv6-host=addr`` 2948 Specify the guest-visible IPv6 address of the host. Default is 2949 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2950 2951 ``restrict=on|off`` 2952 If this option is enabled, the guest will be isolated, i.e. it 2953 will not be able to contact the host and no guest IP packets 2954 will be routed over the host to the outside. This option does 2955 not affect any explicitly set forwarding rules. 2956 2957 ``hostname=name`` 2958 Specifies the client hostname reported by the built-in DHCP 2959 server. 2960 2961 ``dhcpstart=addr`` 2962 Specify the first of the 16 IPs the built-in DHCP server can 2963 assign. Default is the 15th to 31st IP in the guest network, 2964 i.e. x.x.x.15 to x.x.x.31. 2965 2966 ``dns=addr`` 2967 Specify the guest-visible address of the virtual nameserver. The 2968 address must be different from the host address. Default is the 2969 3rd IP in the guest network, i.e. x.x.x.3. 2970 2971 ``ipv6-dns=addr`` 2972 Specify the guest-visible address of the IPv6 virtual 2973 nameserver. The address must be different from the host address. 2974 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2975 2976 ``dnssearch=domain`` 2977 Provides an entry for the domain-search list sent by the 2978 built-in DHCP server. More than one domain suffix can be 2979 transmitted by specifying this option multiple times. If 2980 supported, this will cause the guest to automatically try to 2981 append the given domain suffix(es) in case a domain name can not 2982 be resolved. 2983 2984 Example: 2985 2986 .. parsed-literal:: 2987 2988 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2989 2990 ``domainname=domain`` 2991 Specifies the client domain name reported by the built-in DHCP 2992 server. 2993 2994 ``tftp=dir`` 2995 When using the user mode network stack, activate a built-in TFTP 2996 server. The files in dir will be exposed as the root of a TFTP 2997 server. The TFTP client on the guest must be configured in 2998 binary mode (use the command ``bin`` of the Unix TFTP client). 2999 3000 ``tftp-server-name=name`` 3001 In BOOTP reply, broadcast name as the "TFTP server name" 3002 (RFC2132 option 66). This can be used to advise the guest to 3003 load boot files or configurations from a different server than 3004 the host address. 3005 3006 ``bootfile=file`` 3007 When using the user mode network stack, broadcast file as the 3008 BOOTP filename. In conjunction with ``tftp``, this can be used 3009 to network boot a guest from a local directory. 3010 3011 Example (using pxelinux): 3012 3013 .. parsed-literal:: 3014 3015 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3016 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3017 3018 ``smb=dir[,smbserver=addr]`` 3019 When using the user mode network stack, activate a built-in SMB 3020 server so that Windows OSes can access to the host files in 3021 ``dir`` transparently. The IP address of the SMB server can be 3022 set to addr. By default the 4th IP in the guest network is used, 3023 i.e. x.x.x.4. 3024 3025 In the guest Windows OS, the line: 3026 3027 :: 3028 3029 10.0.2.4 smbserver 3030 3031 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3032 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3033 NT/2000). 3034 3035 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3036 3037 Note that a SAMBA server must be installed on the host OS. 3038 3039 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3040 Redirect incoming TCP or UDP connections to the host port 3041 hostport to the guest IP address guestaddr on guest port 3042 guestport. If guestaddr is not specified, its value is x.x.x.15 3043 (default first address given by the built-in DHCP server). By 3044 specifying hostaddr, the rule can be bound to a specific host 3045 interface. If no connection type is set, TCP is used. This 3046 option can be given multiple times. 3047 3048 For example, to redirect host X11 connection from screen 1 to 3049 guest screen 0, use the following: 3050 3051 .. parsed-literal:: 3052 3053 # on the host 3054 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3055 # this host xterm should open in the guest X11 server 3056 xterm -display :1 3057 3058 To redirect telnet connections from host port 5555 to telnet 3059 port on the guest, use the following: 3060 3061 .. parsed-literal:: 3062 3063 # on the host 3064 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3065 telnet localhost 5555 3066 3067 Then when you use on the host ``telnet localhost 5555``, you 3068 connect to the guest telnet server. 3069 3070 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3071 Forward guest TCP connections to the IP address server on port 3072 port to the character device dev or to a program executed by 3073 cmd:command which gets spawned for each connection. This option 3074 can be given multiple times. 3075 3076 You can either use a chardev directly and have that one used 3077 throughout QEMU's lifetime, like in the following example: 3078 3079 .. parsed-literal:: 3080 3081 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3082 # the guest accesses it 3083 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3084 3085 Or you can execute a command on every TCP connection established 3086 by the guest, so that QEMU behaves similar to an inetd process 3087 for that virtual server: 3088 3089 .. parsed-literal:: 3090 3091 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3092 # and connect the TCP stream to its stdin/stdout 3093 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3094 3095``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3096 Configure a host TAP network backend with ID id. 3097 3098 Use the network script file to configure it and the network script 3099 dfile to deconfigure it. If name is not provided, the OS 3100 automatically provides one. The default network configure script is 3101 ``/etc/qemu-ifup`` and the default network deconfigure script is 3102 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3103 disable script execution. 3104 3105 If running QEMU as an unprivileged user, use the network helper 3106 to configure the TAP interface and attach it to the bridge. 3107 The default network helper executable is 3108 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3109 ``br0``. 3110 3111 ``fd``\ =h can be used to specify the handle of an already opened 3112 host TAP interface. 3113 3114 Examples: 3115 3116 .. parsed-literal:: 3117 3118 #launch a QEMU instance with the default network script 3119 |qemu_system| linux.img -nic tap 3120 3121 .. parsed-literal:: 3122 3123 #launch a QEMU instance with two NICs, each one connected 3124 #to a TAP device 3125 |qemu_system| linux.img \\ 3126 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3127 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3128 3129 .. parsed-literal:: 3130 3131 #launch a QEMU instance with the default network helper to 3132 #connect a TAP device to bridge br0 3133 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3134 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3135 3136``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3137 Connect a host TAP network interface to a host bridge device. 3138 3139 Use the network helper helper to configure the TAP interface and 3140 attach it to the bridge. The default network helper executable is 3141 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3142 ``br0``. 3143 3144 Examples: 3145 3146 .. parsed-literal:: 3147 3148 #launch a QEMU instance with the default network helper to 3149 #connect a TAP device to bridge br0 3150 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3151 3152 .. parsed-literal:: 3153 3154 #launch a QEMU instance with the default network helper to 3155 #connect a TAP device to bridge qemubr0 3156 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3157 3158``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3159 This host network backend can be used to connect the guest's network 3160 to another QEMU virtual machine using a TCP socket connection. If 3161 ``listen`` is specified, QEMU waits for incoming connections on port 3162 (host is optional). ``connect`` is used to connect to another QEMU 3163 instance using the ``listen`` option. ``fd``\ =h specifies an 3164 already opened TCP socket. 3165 3166 Example: 3167 3168 .. parsed-literal:: 3169 3170 # launch a first QEMU instance 3171 |qemu_system| linux.img \\ 3172 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3173 -netdev socket,id=n1,listen=:1234 3174 # connect the network of this instance to the network of the first instance 3175 |qemu_system| linux.img \\ 3176 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3177 -netdev socket,id=n2,connect=127.0.0.1:1234 3178 3179``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3180 Configure a socket host network backend to share the guest's network 3181 traffic with another QEMU virtual machines using a UDP multicast 3182 socket, effectively making a bus for every QEMU with same multicast 3183 address maddr and port. NOTES: 3184 3185 1. Several QEMU can be running on different hosts and share same bus 3186 (assuming correct multicast setup for these hosts). 3187 3188 2. mcast support is compatible with User Mode Linux (argument 3189 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3190 3191 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3192 3193 Example: 3194 3195 .. parsed-literal:: 3196 3197 # launch one QEMU instance 3198 |qemu_system| linux.img \\ 3199 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3200 -netdev socket,id=n1,mcast=230.0.0.1:1234 3201 # launch another QEMU instance on same "bus" 3202 |qemu_system| linux.img \\ 3203 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3204 -netdev socket,id=n2,mcast=230.0.0.1:1234 3205 # launch yet another QEMU instance on same "bus" 3206 |qemu_system| linux.img \\ 3207 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3208 -netdev socket,id=n3,mcast=230.0.0.1:1234 3209 3210 Example (User Mode Linux compat.): 3211 3212 .. parsed-literal:: 3213 3214 # launch QEMU instance (note mcast address selected is UML's default) 3215 |qemu_system| linux.img \\ 3216 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3217 -netdev socket,id=n1,mcast=239.192.168.1:1102 3218 # launch UML 3219 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3220 3221 Example (send packets from host's 1.2.3.4): 3222 3223 .. parsed-literal:: 3224 3225 |qemu_system| linux.img \\ 3226 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3227 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3228 3229``-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]`` 3230 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3231 is a popular protocol to transport Ethernet (and other Layer 2) data 3232 frames between two systems. It is present in routers, firewalls and 3233 the Linux kernel (from version 3.3 onwards). 3234 3235 This transport allows a VM to communicate to another VM, router or 3236 firewall directly. 3237 3238 ``src=srcaddr`` 3239 source address (mandatory) 3240 3241 ``dst=dstaddr`` 3242 destination address (mandatory) 3243 3244 ``udp`` 3245 select udp encapsulation (default is ip). 3246 3247 ``srcport=srcport`` 3248 source udp port. 3249 3250 ``dstport=dstport`` 3251 destination udp port. 3252 3253 ``ipv6`` 3254 force v6, otherwise defaults to v4. 3255 3256 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3257 Cookies are a weak form of security in the l2tpv3 specification. 3258 Their function is mostly to prevent misconfiguration. By default 3259 they are 32 bit. 3260 3261 ``cookie64`` 3262 Set cookie size to 64 bit instead of the default 32 3263 3264 ``counter=off`` 3265 Force a 'cut-down' L2TPv3 with no counter as in 3266 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3267 3268 ``pincounter=on`` 3269 Work around broken counter handling in peer. This may also help 3270 on networks which have packet reorder. 3271 3272 ``offset=offset`` 3273 Add an extra offset between header and data 3274 3275 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3276 the bridge br-lan on the remote Linux host 1.2.3.4: 3277 3278 .. parsed-literal:: 3279 3280 # Setup tunnel on linux host using raw ip as encapsulation 3281 # on 1.2.3.4 3282 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3283 encap udp udp_sport 16384 udp_dport 16384 3284 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3285 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3286 ifconfig vmtunnel0 mtu 1500 3287 ifconfig vmtunnel0 up 3288 brctl addif br-lan vmtunnel0 3289 3290 3291 # on 4.3.2.1 3292 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3293 3294 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3295 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3296 3297``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3298 Configure VDE backend to connect to PORT n of a vde switch running 3299 on host and listening for incoming connections on socketpath. Use 3300 GROUP groupname and MODE octalmode to change default ownership and 3301 permissions for communication port. This option is only available if 3302 QEMU has been compiled with vde support enabled. 3303 3304 Example: 3305 3306 .. parsed-literal:: 3307 3308 # launch vde switch 3309 vde_switch -F -sock /tmp/myswitch 3310 # launch QEMU instance 3311 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3312 3313``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3314 Establish a vhost-user netdev, backed by a chardev id. The chardev 3315 should be a unix domain socket backed one. The vhost-user uses a 3316 specifically defined protocol to pass vhost ioctl replacement 3317 messages to an application on the other end of the socket. On 3318 non-MSIX guests, the feature can be forced with vhostforce. Use 3319 'queues=n' to specify the number of queues to be created for 3320 multiqueue vhost-user. 3321 3322 Example: 3323 3324 :: 3325 3326 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3327 -numa node,memdev=mem \ 3328 -chardev socket,id=chr0,path=/path/to/socket \ 3329 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3330 -device virtio-net-pci,netdev=net0 3331 3332``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3333 Establish a vhost-vdpa netdev. 3334 3335 vDPA device is a device that uses a datapath which complies with 3336 the virtio specifications with a vendor specific control path. 3337 vDPA devices can be both physically located on the hardware or 3338 emulated by software. 3339 3340``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3341 Create a hub port on the emulated hub with ID hubid. 3342 3343 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3344 instead of a single netdev. Alternatively, you can also connect the 3345 hubport to another netdev with ID nd by using the ``netdev=nd`` 3346 option. 3347 3348``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3349 Legacy option to configure or create an on-board (or machine 3350 default) Network Interface Card(NIC) and connect it either to the 3351 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3352 If model is omitted, then the default NIC model associated with the 3353 machine type is used. Note that the default NIC model may change in 3354 future QEMU releases, so it is highly recommended to always specify 3355 a model. Optionally, the MAC address can be changed to mac, the 3356 device address set to addr (PCI cards only), and a name can be 3357 assigned for use in monitor commands. Optionally, for PCI cards, you 3358 can specify the number v of MSI-X vectors that the card should have; 3359 this option currently only affects virtio cards; set v = 0 to 3360 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3361 created. QEMU can emulate several different models of network card. 3362 Use ``-net nic,model=help`` for a list of available devices for your 3363 target. 3364 3365``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3366 Configure a host network backend (with the options corresponding to 3367 the same ``-netdev`` option) and connect it to the emulated hub 0 3368 (the default hub). Use name to specify the name of the hub port. 3369ERST 3370 3371DEFHEADING() 3372 3373DEFHEADING(Character device options:) 3374 3375DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3376 "-chardev help\n" 3377 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3378 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3379 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3380 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3381 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3382 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3383 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3384 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3385 " [,logfile=PATH][,logappend=on|off]\n" 3386 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3387 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3388 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3389 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3390 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3391 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3392#ifdef _WIN32 3393 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3394 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3395#else 3396 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3397 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3398#endif 3399#ifdef CONFIG_BRLAPI 3400 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3401#endif 3402#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3403 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3404 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3405#endif 3406#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3407 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3408#endif 3409#if defined(CONFIG_SPICE) 3410 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3411 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3412#endif 3413 , QEMU_ARCH_ALL 3414) 3415 3416SRST 3417The general form of a character device option is: 3418 3419``-chardev backend,id=id[,mux=on|off][,options]`` 3420 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3421 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3422 ``pty``, ``stdio``, ``braille``, ``parallel``, 3423 ``spicevmc``, ``spiceport``. The specific backend will determine the 3424 applicable options. 3425 3426 Use ``-chardev help`` to print all available chardev backend types. 3427 3428 All devices must have an id, which can be any string up to 127 3429 characters long. It is used to uniquely identify this device in 3430 other command line directives. 3431 3432 A character device may be used in multiplexing mode by multiple 3433 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3434 a "1:N" device, and here the "1" end is your specified chardev 3435 backend, and the "N" end is the various parts of QEMU that can talk 3436 to a chardev. If you create a chardev with ``id=myid`` and 3437 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3438 and you can then configure multiple front ends to use that chardev 3439 ID for their input/output. Up to four different front ends can be 3440 connected to a single multiplexed chardev. (Without multiplexing 3441 enabled, a chardev can only be used by a single front end.) For 3442 instance you could use this to allow a single stdio chardev to be 3443 used by two serial ports and the QEMU monitor: 3444 3445 :: 3446 3447 -chardev stdio,mux=on,id=char0 \ 3448 -mon chardev=char0,mode=readline \ 3449 -serial chardev:char0 \ 3450 -serial chardev:char0 3451 3452 You can have more than one multiplexer in a system configuration; 3453 for instance you could have a TCP port multiplexed between UART 0 3454 and UART 1, and stdio multiplexed between the QEMU monitor and a 3455 parallel port: 3456 3457 :: 3458 3459 -chardev stdio,mux=on,id=char0 \ 3460 -mon chardev=char0,mode=readline \ 3461 -parallel chardev:char0 \ 3462 -chardev tcp,...,mux=on,id=char1 \ 3463 -serial chardev:char1 \ 3464 -serial chardev:char1 3465 3466 When you're using a multiplexed character device, some escape 3467 sequences are interpreted in the input. See the chapter about 3468 :ref:`keys in the character backend multiplexer` in the 3469 System Emulation Users Guide for more details. 3470 3471 Note that some other command line options may implicitly create 3472 multiplexed character backends; for instance ``-serial mon:stdio`` 3473 creates a multiplexed stdio backend connected to the serial port and 3474 the QEMU monitor, and ``-nographic`` also multiplexes the console 3475 and the monitor to stdio. 3476 3477 There is currently no support for multiplexing in the other 3478 direction (where a single QEMU front end takes input and output from 3479 multiple chardevs). 3480 3481 Every backend supports the ``logfile`` option, which supplies the 3482 path to a file to record all data transmitted via the backend. The 3483 ``logappend`` option controls whether the log file will be truncated 3484 or appended to when opened. 3485 3486The available backends are: 3487 3488``-chardev null,id=id`` 3489 A void device. This device will not emit any data, and will drop any 3490 data it receives. The null backend does not take any options. 3491 3492``-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]`` 3493 Create a two-way stream socket, which can be either a TCP or a unix 3494 socket. A unix socket will be created if ``path`` is specified. 3495 Behaviour is undefined if TCP options are specified for a unix 3496 socket. 3497 3498 ``server=on|off`` specifies that the socket shall be a listening socket. 3499 3500 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3501 to connect to a listening socket. 3502 3503 ``telnet=on|off`` specifies that traffic on the socket should interpret 3504 telnet escape sequences. 3505 3506 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3507 communication. 3508 3509 ``reconnect`` sets the timeout for reconnecting on non-server 3510 sockets when the remote end goes away. qemu will delay this many 3511 seconds and then attempt to reconnect. Zero disables reconnecting, 3512 and is the default. 3513 3514 ``tls-creds`` requests enablement of the TLS protocol for 3515 encryption, and specifies the id of the TLS credentials to use for 3516 the handshake. The credentials must be previously created with the 3517 ``-object tls-creds`` argument. 3518 3519 ``tls-auth`` provides the ID of the QAuthZ authorization object 3520 against which the client's x509 distinguished name will be 3521 validated. This object is only resolved at time of use, so can be 3522 deleted and recreated on the fly while the chardev server is active. 3523 If missing, it will default to denying access. 3524 3525 TCP and unix socket options are given below: 3526 3527 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3528 ``host`` for a listening socket specifies the local address to 3529 be bound. For a connecting socket species the remote host to 3530 connect to. ``host`` is optional for listening sockets. If not 3531 specified it defaults to ``0.0.0.0``. 3532 3533 ``port`` for a listening socket specifies the local port to be 3534 bound. For a connecting socket specifies the port on the remote 3535 host to connect to. ``port`` can be given as either a port 3536 number or a service name. ``port`` is required. 3537 3538 ``to`` is only relevant to listening sockets. If it is 3539 specified, and ``port`` cannot be bound, QEMU will attempt to 3540 bind to subsequent ports up to and including ``to`` until it 3541 succeeds. ``to`` must be specified as a port number. 3542 3543 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3544 or IPv6 must be used. If neither is specified the socket may 3545 use either protocol. 3546 3547 ``nodelay=on|off`` disables the Nagle algorithm. 3548 3549 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3550 ``path`` specifies the local path of the unix socket. ``path`` 3551 is required. 3552 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3553 rather than the filesystem. Optional, defaults to false. 3554 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3555 rather than the full sun_path length. Optional, defaults to true. 3556 3557``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3558 Sends all traffic from the guest to a remote host over UDP. 3559 3560 ``host`` specifies the remote host to connect to. If not specified 3561 it defaults to ``localhost``. 3562 3563 ``port`` specifies the port on the remote host to connect to. 3564 ``port`` is required. 3565 3566 ``localaddr`` specifies the local address to bind to. If not 3567 specified it defaults to ``0.0.0.0``. 3568 3569 ``localport`` specifies the local port to bind to. If not specified 3570 any available local port will be used. 3571 3572 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3573 If neither is specified the device may use either protocol. 3574 3575``-chardev msmouse,id=id`` 3576 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3577 does not take any options. 3578 3579``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3580 Connect to a QEMU text console. ``vc`` may optionally be given a 3581 specific size. 3582 3583 ``width`` and ``height`` specify the width and height respectively 3584 of the console, in pixels. 3585 3586 ``cols`` and ``rows`` specify that the console be sized to fit a 3587 text console with the given dimensions. 3588 3589``-chardev ringbuf,id=id[,size=size]`` 3590 Create a ring buffer with fixed size ``size``. size must be a power 3591 of two and defaults to ``64K``. 3592 3593``-chardev file,id=id,path=path[,input-path=input-path]`` 3594 Log all traffic received from the guest to a file. 3595 3596 ``path`` specifies the path of the file to be opened. This file will 3597 be created if it does not already exist, and overwritten if it does. 3598 ``path`` is required. 3599 3600 If ``input-path`` is specified, this is the path of a second file 3601 which will be used for input. If ``input-path`` is not specified, 3602 no input will be available from the chardev. 3603 3604 Note that ``input-path`` is not supported on Windows hosts. 3605 3606``-chardev pipe,id=id,path=path`` 3607 Create a two-way connection to the guest. The behaviour differs 3608 slightly between Windows hosts and other hosts: 3609 3610 On Windows, a single duplex pipe will be created at 3611 ``\\.pipe\path``. 3612 3613 On other hosts, 2 pipes will be created called ``path.in`` and 3614 ``path.out``. Data written to ``path.in`` will be received by the 3615 guest. Data written by the guest can be read from ``path.out``. QEMU 3616 will not create these fifos, and requires them to be present. 3617 3618 ``path`` forms part of the pipe path as described above. ``path`` is 3619 required. 3620 3621``-chardev console,id=id`` 3622 Send traffic from the guest to QEMU's standard output. ``console`` 3623 does not take any options. 3624 3625 ``console`` is only available on Windows hosts. 3626 3627``-chardev serial,id=id,path=path`` 3628 Send traffic from the guest to a serial device on the host. 3629 3630 On Unix hosts serial will actually accept any tty device, not only 3631 serial lines. 3632 3633 ``path`` specifies the name of the serial device to open. 3634 3635``-chardev pty,id=id`` 3636 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3637 does not take any options. 3638 3639 ``pty`` is not available on Windows hosts. 3640 3641``-chardev stdio,id=id[,signal=on|off]`` 3642 Connect to standard input and standard output of the QEMU process. 3643 3644 ``signal`` controls if signals are enabled on the terminal, that 3645 includes exiting QEMU with the key sequence Control-c. This option 3646 is enabled by default, use ``signal=off`` to disable it. 3647 3648``-chardev braille,id=id`` 3649 Connect to a local BrlAPI server. ``braille`` does not take any 3650 options. 3651 3652``-chardev parallel,id=id,path=path`` 3653 \ 3654 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3655 hosts. 3656 3657 Connect to a local parallel port. 3658 3659 ``path`` specifies the path to the parallel port device. ``path`` is 3660 required. 3661 3662``-chardev spicevmc,id=id,debug=debug,name=name`` 3663 ``spicevmc`` is only available when spice support is built in. 3664 3665 ``debug`` debug level for spicevmc 3666 3667 ``name`` name of spice channel to connect to 3668 3669 Connect to a spice virtual machine channel, such as vdiport. 3670 3671``-chardev spiceport,id=id,debug=debug,name=name`` 3672 ``spiceport`` is only available when spice support is built in. 3673 3674 ``debug`` debug level for spicevmc 3675 3676 ``name`` name of spice port to connect to 3677 3678 Connect to a spice port, allowing a Spice client to handle the 3679 traffic identified by a name (preferably a fqdn). 3680ERST 3681 3682DEFHEADING() 3683 3684#ifdef CONFIG_TPM 3685DEFHEADING(TPM device options:) 3686 3687DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3688 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3689 " use path to provide path to a character device; default is /dev/tpm0\n" 3690 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3691 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3692 "-tpmdev emulator,id=id,chardev=dev\n" 3693 " configure the TPM device using chardev backend\n", 3694 QEMU_ARCH_ALL) 3695SRST 3696The general form of a TPM device option is: 3697 3698``-tpmdev backend,id=id[,options]`` 3699 The specific backend type will determine the applicable options. The 3700 ``-tpmdev`` option creates the TPM backend and requires a 3701 ``-device`` option that specifies the TPM frontend interface model. 3702 3703 Use ``-tpmdev help`` to print all available TPM backend types. 3704 3705The available backends are: 3706 3707``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3708 (Linux-host only) Enable access to the host's TPM using the 3709 passthrough driver. 3710 3711 ``path`` specifies the path to the host's TPM device, i.e., on a 3712 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3713 default ``/dev/tpm0`` is used. 3714 3715 ``cancel-path`` specifies the path to the host TPM device's sysfs 3716 entry allowing for cancellation of an ongoing TPM command. 3717 ``cancel-path`` is optional and by default QEMU will search for the 3718 sysfs entry to use. 3719 3720 Some notes about using the host's TPM with the passthrough driver: 3721 3722 The TPM device accessed by the passthrough driver must not be used 3723 by any other application on the host. 3724 3725 Since the host's firmware (BIOS/UEFI) has already initialized the 3726 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3727 the TPM again and may therefore not show a TPM-specific menu that 3728 would otherwise allow the user to configure the TPM, e.g., allow the 3729 user to enable/disable or activate/deactivate the TPM. Further, if 3730 TPM ownership is released from within a VM then the host's TPM will 3731 get disabled and deactivated. To enable and activate the TPM again 3732 afterwards, the host has to be rebooted and the user is required to 3733 enter the firmware's menu to enable and activate the TPM. If the TPM 3734 is left disabled and/or deactivated most TPM commands will fail. 3735 3736 To create a passthrough TPM use the following two options: 3737 3738 :: 3739 3740 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3741 3742 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3743 ``tpmdev=tpm0`` in the device option. 3744 3745``-tpmdev emulator,id=id,chardev=dev`` 3746 (Linux-host only) Enable access to a TPM emulator using Unix domain 3747 socket based chardev backend. 3748 3749 ``chardev`` specifies the unique ID of a character device backend 3750 that provides connection to the software TPM server. 3751 3752 To create a TPM emulator backend device with chardev socket backend: 3753 3754 :: 3755 3756 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3757ERST 3758 3759DEFHEADING() 3760 3761#endif 3762 3763DEFHEADING(Boot Image or Kernel specific:) 3764SRST 3765There are broadly 4 ways you can boot a system with QEMU. 3766 3767 - specify a firmware and let it control finding a kernel 3768 - specify a firmware and pass a hint to the kernel to boot 3769 - direct kernel image boot 3770 - manually load files into the guest's address space 3771 3772The third method is useful for quickly testing kernels but as there is 3773no firmware to pass configuration information to the kernel the 3774hardware must either be probeable, the kernel built for the exact 3775configuration or passed some configuration data (e.g. a DTB blob) 3776which tells the kernel what drivers it needs. This exact details are 3777often hardware specific. 3778 3779The final method is the most generic way of loading images into the 3780guest address space and used mostly for ``bare metal`` type 3781development where the reset vectors of the processor are taken into 3782account. 3783 3784ERST 3785 3786SRST 3787 3788For x86 machines and some other architectures ``-bios`` will generally 3789do the right thing with whatever it is given. For other machines the 3790more strict ``-pflash`` option needs an image that is sized for the 3791flash device for the given machine type. 3792 3793Please see the :ref:`system-targets-ref` section of the manual for 3794more detailed documentation. 3795 3796ERST 3797 3798DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3799 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3800SRST 3801``-bios file`` 3802 Set the filename for the BIOS. 3803ERST 3804 3805DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3806 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3807SRST 3808``-pflash file`` 3809 Use file as a parallel flash image. 3810ERST 3811 3812SRST 3813 3814The kernel options were designed to work with Linux kernels although 3815other things (like hypervisors) can be packaged up as a kernel 3816executable image. The exact format of a executable image is usually 3817architecture specific. 3818 3819The way in which the kernel is started (what address it is loaded at, 3820what if any information is passed to it via CPU registers, the state 3821of the hardware when it is started, and so on) is also architecture 3822specific. Typically it follows the specification laid down by the 3823Linux kernel for how kernels for that architecture must be started. 3824 3825ERST 3826 3827DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3828 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3829SRST 3830``-kernel bzImage`` 3831 Use bzImage as kernel image. The kernel can be either a Linux kernel 3832 or in multiboot format. 3833ERST 3834 3835DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3836 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3837SRST 3838``-append cmdline`` 3839 Use cmdline as kernel command line 3840ERST 3841 3842DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3843 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3844SRST 3845``-initrd file`` 3846 Use file as initial ram disk. 3847 3848``-initrd "file1 arg=foo,file2"`` 3849 This syntax is only available with multiboot. 3850 3851 Use file1 and file2 as modules and pass arg=foo as parameter to the 3852 first module. 3853ERST 3854 3855DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3856 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3857SRST 3858``-dtb file`` 3859 Use file as a device tree binary (dtb) image and pass it to the 3860 kernel on boot. 3861ERST 3862 3863SRST 3864 3865Finally you can also manually load images directly into the address 3866space of the guest. This is most useful for developers who already 3867know the layout of their guest and take care to ensure something sane 3868will happen when the reset vector executes. 3869 3870The generic loader can be invoked by using the loader device: 3871 3872``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3873 3874there is also the guest loader which operates in a similar way but 3875tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3876the guest image is: 3877 3878``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3879 3880ERST 3881 3882DEFHEADING() 3883 3884DEFHEADING(Debug/Expert options:) 3885 3886DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3887 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3888 " Policy for handling deprecated management interfaces\n" 3889 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3890 " Policy for handling unstable management interfaces\n", 3891 QEMU_ARCH_ALL) 3892SRST 3893``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3894 Set policy for handling deprecated management interfaces (experimental): 3895 3896 ``deprecated-input=accept`` (default) 3897 Accept deprecated commands and arguments 3898 ``deprecated-input=reject`` 3899 Reject deprecated commands and arguments 3900 ``deprecated-input=crash`` 3901 Crash on deprecated commands and arguments 3902 ``deprecated-output=accept`` (default) 3903 Emit deprecated command results and events 3904 ``deprecated-output=hide`` 3905 Suppress deprecated command results and events 3906 3907 Limitation: covers only syntactic aspects of QMP. 3908 3909``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3910 Set policy for handling unstable management interfaces (experimental): 3911 3912 ``unstable-input=accept`` (default) 3913 Accept unstable commands and arguments 3914 ``unstable-input=reject`` 3915 Reject unstable commands and arguments 3916 ``unstable-input=crash`` 3917 Crash on unstable commands and arguments 3918 ``unstable-output=accept`` (default) 3919 Emit unstable command results and events 3920 ``unstable-output=hide`` 3921 Suppress unstable command results and events 3922 3923 Limitation: covers only syntactic aspects of QMP. 3924ERST 3925 3926DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3927 "-fw_cfg [name=]<name>,file=<file>\n" 3928 " add named fw_cfg entry with contents from file\n" 3929 "-fw_cfg [name=]<name>,string=<str>\n" 3930 " add named fw_cfg entry with contents from string\n", 3931 QEMU_ARCH_ALL) 3932SRST 3933``-fw_cfg [name=]name,file=file`` 3934 Add named fw\_cfg entry with contents from file file. 3935 3936``-fw_cfg [name=]name,string=str`` 3937 Add named fw\_cfg entry with contents from string str. 3938 3939 The terminating NUL character of the contents of str will not be 3940 included as part of the fw\_cfg item data. To insert contents with 3941 embedded NUL characters, you have to use the file parameter. 3942 3943 The fw\_cfg entries are passed by QEMU through to the guest. 3944 3945 Example: 3946 3947 :: 3948 3949 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3950 3951 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3952 from ./my\_blob.bin. 3953ERST 3954 3955DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3956 "-serial dev redirect the serial port to char device 'dev'\n", 3957 QEMU_ARCH_ALL) 3958SRST 3959``-serial dev`` 3960 Redirect the virtual serial port to host character device dev. The 3961 default device is ``vc`` in graphical mode and ``stdio`` in non 3962 graphical mode. 3963 3964 This option can be used several times to simulate up to 4 serial 3965 ports. 3966 3967 Use ``-serial none`` to disable all serial ports. 3968 3969 Available character devices are: 3970 3971 ``vc[:WxH]`` 3972 Virtual console. Optionally, a width and height can be given in 3973 pixel with 3974 3975 :: 3976 3977 vc:800x600 3978 3979 It is also possible to specify width or height in characters: 3980 3981 :: 3982 3983 vc:80Cx24C 3984 3985 ``pty`` 3986 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3987 3988 ``none`` 3989 No device is allocated. 3990 3991 ``null`` 3992 void device 3993 3994 ``chardev:id`` 3995 Use a named character device defined with the ``-chardev`` 3996 option. 3997 3998 ``/dev/XXX`` 3999 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4000 port parameters are set according to the emulated ones. 4001 4002 ``/dev/parportN`` 4003 [Linux only, parallel port only] Use host parallel port N. 4004 Currently SPP and EPP parallel port features can be used. 4005 4006 ``file:filename`` 4007 Write output to filename. No character can be read. 4008 4009 ``stdio`` 4010 [Unix only] standard input/output 4011 4012 ``pipe:filename`` 4013 name pipe filename 4014 4015 ``COMn`` 4016 [Windows only] Use host serial port n 4017 4018 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4019 This implements UDP Net Console. When remote\_host or src\_ip 4020 are not specified they default to ``0.0.0.0``. When not using a 4021 specified src\_port a random port is automatically chosen. 4022 4023 If you just want a simple readonly console you can use 4024 ``netcat`` or ``nc``, by starting QEMU with: 4025 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4026 QEMU writes something to that port it will appear in the 4027 netconsole session. 4028 4029 If you plan to send characters back via netconsole or you want 4030 to stop and start QEMU a lot of times, you should have QEMU use 4031 the same source port each time by using something like ``-serial 4032 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4033 version of netcat which can listen to a TCP port and send and 4034 receive characters via udp. If you have a patched version of 4035 netcat which activates telnet remote echo and single char 4036 transfer, then you can use the following options to set up a 4037 netcat redirector to allow telnet on port 5555 to access the 4038 QEMU port. 4039 4040 ``QEMU Options:`` 4041 -serial udp::4555@:4556 4042 4043 ``netcat options:`` 4044 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4045 4046 ``telnet options:`` 4047 localhost 5555 4048 4049 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4050 The TCP Net Console has two modes of operation. It can send the 4051 serial I/O to a location or wait for a connection from a 4052 location. By default the TCP Net Console is sent to host at the 4053 port. If you use the ``server=on`` option QEMU will wait for a client 4054 socket application to connect to the port before continuing, 4055 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4056 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4057 option only applies if ``server=no`` is set, if the connection goes 4058 down it will attempt to reconnect at the given interval. If host 4059 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4060 time is accepted. You can use ``telnet=on`` to connect to the 4061 corresponding character device. 4062 4063 ``Example to send tcp console to 192.168.0.2 port 4444`` 4064 -serial tcp:192.168.0.2:4444 4065 4066 ``Example to listen and wait on port 4444 for connection`` 4067 -serial tcp::4444,server=on 4068 4069 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4070 -serial tcp:192.168.0.100:4444,server=on,wait=off 4071 4072 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4073 The telnet protocol is used instead of raw tcp sockets. The 4074 options work the same as if you had specified ``-serial tcp``. 4075 The difference is that the port acts like a telnet server or 4076 client using telnet option negotiation. This will also allow you 4077 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4078 supports sending the break sequence. Typically in unix telnet 4079 you do it with Control-] and then type "send break" followed by 4080 pressing the enter key. 4081 4082 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4083 The WebSocket protocol is used instead of raw tcp socket. The 4084 port acts as a WebSocket server. Client mode is not supported. 4085 4086 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4087 A unix domain socket is used instead of a tcp socket. The option 4088 works the same as if you had specified ``-serial tcp`` except 4089 the unix domain socket path is used for connections. 4090 4091 ``mon:dev_string`` 4092 This is a special option to allow the monitor to be multiplexed 4093 onto another serial port. The monitor is accessed with key 4094 sequence of Control-a and then pressing c. dev\_string should be 4095 any one of the serial devices specified above. An example to 4096 multiplex the monitor onto a telnet server listening on port 4097 4444 would be: 4098 4099 ``-serial mon:telnet::4444,server=on,wait=off`` 4100 4101 When the monitor is multiplexed to stdio in this way, Ctrl+C 4102 will not terminate QEMU any more but will be passed to the guest 4103 instead. 4104 4105 ``braille`` 4106 Braille device. This will use BrlAPI to display the braille 4107 output on a real or fake device. 4108 4109 ``msmouse`` 4110 Three button serial mouse. Configure the guest to use Microsoft 4111 protocol. 4112ERST 4113 4114DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4115 "-parallel dev redirect the parallel port to char device 'dev'\n", 4116 QEMU_ARCH_ALL) 4117SRST 4118``-parallel dev`` 4119 Redirect the virtual parallel port to host device dev (same devices 4120 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4121 to use hardware devices connected on the corresponding host parallel 4122 port. 4123 4124 This option can be used several times to simulate up to 3 parallel 4125 ports. 4126 4127 Use ``-parallel none`` to disable all parallel ports. 4128ERST 4129 4130DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4131 "-monitor dev redirect the monitor to char device 'dev'\n", 4132 QEMU_ARCH_ALL) 4133SRST 4134``-monitor dev`` 4135 Redirect the monitor to host device dev (same devices as the serial 4136 port). The default device is ``vc`` in graphical mode and ``stdio`` 4137 in non graphical mode. Use ``-monitor none`` to disable the default 4138 monitor. 4139ERST 4140DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4141 "-qmp dev like -monitor but opens in 'control' mode\n", 4142 QEMU_ARCH_ALL) 4143SRST 4144``-qmp dev`` 4145 Like -monitor but opens in 'control' mode. 4146ERST 4147DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4148 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4149 QEMU_ARCH_ALL) 4150SRST 4151``-qmp-pretty dev`` 4152 Like -qmp but uses pretty JSON formatting. 4153ERST 4154 4155DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4156 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4157SRST 4158``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4159 Setup monitor on chardev name. ``mode=control`` configures 4160 a QMP monitor (a JSON RPC-style protocol) and it is not the 4161 same as HMP, the human monitor that has a "(qemu)" prompt. 4162 ``pretty`` is only valid when ``mode=control``, 4163 turning on JSON pretty printing to ease 4164 human reading and debugging. 4165ERST 4166 4167DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4168 "-debugcon dev redirect the debug console to char device 'dev'\n", 4169 QEMU_ARCH_ALL) 4170SRST 4171``-debugcon dev`` 4172 Redirect the debug console to host device dev (same devices as the 4173 serial port). The debug console is an I/O port which is typically 4174 port 0xe9; writing to that I/O port sends output to this device. The 4175 default device is ``vc`` in graphical mode and ``stdio`` in non 4176 graphical mode. 4177ERST 4178 4179DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4180 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4181SRST 4182``-pidfile file`` 4183 Store the QEMU process PID in file. It is useful if you launch QEMU 4184 from a script. 4185ERST 4186 4187DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4188 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4189SRST 4190``-singlestep`` 4191 Run the emulation in single step mode. 4192ERST 4193 4194DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4195 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4196 QEMU_ARCH_ALL) 4197SRST 4198``--preconfig`` 4199 Pause QEMU for interactive configuration before the machine is 4200 created, which allows querying and configuring properties that will 4201 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4202 exit the preconfig state and move to the next state (i.e. run guest 4203 if -S isn't used or pause the second time if -S is used). This 4204 option is experimental. 4205ERST 4206 4207DEF("S", 0, QEMU_OPTION_S, \ 4208 "-S freeze CPU at startup (use 'c' to start execution)\n", 4209 QEMU_ARCH_ALL) 4210SRST 4211``-S`` 4212 Do not start CPU at startup (you must type 'c' in the monitor). 4213ERST 4214 4215DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4216 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4217 " run qemu with overcommit hints\n" 4218 " mem-lock=on|off controls memory lock support (default: off)\n" 4219 " cpu-pm=on|off controls cpu power management (default: off)\n", 4220 QEMU_ARCH_ALL) 4221SRST 4222``-overcommit mem-lock=on|off`` 4223 \ 4224``-overcommit cpu-pm=on|off`` 4225 Run qemu with hints about host resource overcommit. The default is 4226 to assume that host overcommits all resources. 4227 4228 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4229 (disabled by default). This works when host memory is not 4230 overcommitted and reduces the worst-case latency for guest. 4231 4232 Guest ability to manage power state of host cpus (increasing latency 4233 for other processes on the same host cpu, but decreasing latency for 4234 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4235 works best when host CPU is not overcommitted. When used, host 4236 estimates of CPU cycle and power utilization will be incorrect, not 4237 taking into account guest idle time. 4238ERST 4239 4240DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4241 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4242 " the guest without waiting for gdb to connect; use -S too\n" 4243 " if you want it to not start execution.)\n", 4244 QEMU_ARCH_ALL) 4245SRST 4246``-gdb dev`` 4247 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4248 in the System Emulation Users Guide). Note that this option does not pause QEMU 4249 execution -- if you want QEMU to not start the guest until you 4250 connect with gdb and issue a ``continue`` command, you will need to 4251 also pass the ``-S`` option to QEMU. 4252 4253 The most usual configuration is to listen on a local TCP socket:: 4254 4255 -gdb tcp::3117 4256 4257 but you can specify other backends; UDP, pseudo TTY, or even stdio 4258 are all reasonable use cases. For example, a stdio connection 4259 allows you to start QEMU from within gdb and establish the 4260 connection via a pipe: 4261 4262 .. parsed-literal:: 4263 4264 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4265ERST 4266 4267DEF("s", 0, QEMU_OPTION_s, \ 4268 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4269 QEMU_ARCH_ALL) 4270SRST 4271``-s`` 4272 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4273 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4274ERST 4275 4276DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4277 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4278 QEMU_ARCH_ALL) 4279SRST 4280``-d item1[,...]`` 4281 Enable logging of specified items. Use '-d help' for a list of log 4282 items. 4283ERST 4284 4285DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4286 "-D logfile output log to logfile (default stderr)\n", 4287 QEMU_ARCH_ALL) 4288SRST 4289``-D logfile`` 4290 Output log in logfile instead of to stderr 4291ERST 4292 4293DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4294 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4295 QEMU_ARCH_ALL) 4296SRST 4297``-dfilter range1[,...]`` 4298 Filter debug output to that relevant to a range of target addresses. 4299 The filter spec can be either start+size, start-size or start..end 4300 where start end and size are the addresses and sizes required. For 4301 example: 4302 4303 :: 4304 4305 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4306 4307 Will dump output for any code in the 0x1000 sized block starting at 4308 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4309 another 0x1000 sized block starting at 0xffffffc00005f000. 4310ERST 4311 4312DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4313 "-seed number seed the pseudo-random number generator\n", 4314 QEMU_ARCH_ALL) 4315SRST 4316``-seed number`` 4317 Force the guest to use a deterministic pseudo-random number 4318 generator, seeded with number. This does not affect crypto routines 4319 within the host. 4320ERST 4321 4322DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4323 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4324 QEMU_ARCH_ALL) 4325SRST 4326``-L path`` 4327 Set the directory for the BIOS, VGA BIOS and keymaps. 4328 4329 To list all the data directories, use ``-L help``. 4330ERST 4331 4332DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4333 "-enable-kvm enable KVM full virtualization support\n", 4334 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4335 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4336SRST 4337``-enable-kvm`` 4338 Enable KVM full virtualization support. This option is only 4339 available if KVM support is enabled when compiling. 4340ERST 4341 4342DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4343 "-xen-domid id specify xen guest domain id\n", 4344 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4345DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4346 "-xen-attach attach to existing xen domain\n" 4347 " libxl will use this when starting QEMU\n", 4348 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4349DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4350 "-xen-domid-restrict restrict set of available xen operations\n" 4351 " to specified domain id. (Does not affect\n" 4352 " xenpv machine type).\n", 4353 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4354SRST 4355``-xen-domid id`` 4356 Specify xen guest domain id (XEN only). 4357 4358``-xen-attach`` 4359 Attach to existing xen domain. libxl will use this when starting 4360 QEMU (XEN only). Restrict set of available xen operations to 4361 specified domain id (XEN only). 4362ERST 4363 4364DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4365 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4366SRST 4367``-no-reboot`` 4368 Exit instead of rebooting. 4369ERST 4370 4371DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4372 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4373SRST 4374``-no-shutdown`` 4375 Don't exit QEMU on guest shutdown, but instead only stop the 4376 emulation. This allows for instance switching to monitor to commit 4377 changes to the disk image. 4378ERST 4379 4380DEF("action", HAS_ARG, QEMU_OPTION_action, 4381 "-action reboot=reset|shutdown\n" 4382 " action when guest reboots [default=reset]\n" 4383 "-action shutdown=poweroff|pause\n" 4384 " action when guest shuts down [default=poweroff]\n" 4385 "-action panic=pause|shutdown|exit-failure|none\n" 4386 " action when guest panics [default=shutdown]\n" 4387 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4388 " action when watchdog fires [default=reset]\n", 4389 QEMU_ARCH_ALL) 4390SRST 4391``-action event=action`` 4392 The action parameter serves to modify QEMU's default behavior when 4393 certain guest events occur. It provides a generic method for specifying the 4394 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4395 parameters. 4396 4397 Examples: 4398 4399 ``-action panic=none`` 4400 ``-action reboot=shutdown,shutdown=pause`` 4401 ``-device i6300esb -action watchdog=pause`` 4402 4403ERST 4404 4405DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4406 "-loadvm [tag|id]\n" \ 4407 " start right away with a saved state (loadvm in monitor)\n", 4408 QEMU_ARCH_ALL) 4409SRST 4410``-loadvm file`` 4411 Start right away with a saved state (``loadvm`` in monitor) 4412ERST 4413 4414#ifndef _WIN32 4415DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4416 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4417#endif 4418SRST 4419``-daemonize`` 4420 Daemonize the QEMU process after initialization. QEMU will not 4421 detach from standard IO until it is ready to receive connections on 4422 any of its devices. This option is a useful way for external 4423 programs to launch QEMU without having to cope with initialization 4424 race conditions. 4425ERST 4426 4427DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4428 "-option-rom rom load a file, rom, into the option ROM space\n", 4429 QEMU_ARCH_ALL) 4430SRST 4431``-option-rom file`` 4432 Load the contents of file as an option ROM. This option is useful to 4433 load things like EtherBoot. 4434ERST 4435 4436DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4437 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4438 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4439 QEMU_ARCH_ALL) 4440 4441SRST 4442``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4443 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4444 the current UTC or local time, respectively. ``localtime`` is 4445 required for correct date in MS-DOS or Windows. To start at a 4446 specific point in time, provide datetime in the format 4447 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4448 4449 By default the RTC is driven by the host system time. This allows 4450 using of the RTC as accurate reference clock inside the guest, 4451 specifically if the host time is smoothly following an accurate 4452 external reference clock, e.g. via NTP. If you want to isolate the 4453 guest time from the host, you can set ``clock`` to ``rt`` instead, 4454 which provides a host monotonic clock if host support it. To even 4455 prevent the RTC from progressing during suspension, you can set 4456 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4457 recommended especially in icount mode in order to preserve 4458 determinism; however, note that in icount mode the speed of the 4459 virtual clock is variable and can in general differ from the host 4460 clock. 4461 4462 Enable ``driftfix`` (i386 targets only) if you experience time drift 4463 problems, specifically with Windows' ACPI HAL. This option will try 4464 to figure out how many timer interrupts were not processed by the 4465 Windows guest and will re-inject them. 4466ERST 4467 4468DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4469 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4470 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4471 " instruction, enable aligning the host and virtual clocks\n" \ 4472 " or disable real time cpu sleeping, and optionally enable\n" \ 4473 " record-and-replay mode\n", QEMU_ARCH_ALL) 4474SRST 4475``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4476 Enable virtual instruction counter. The virtual cpu will execute one 4477 instruction every 2^N ns of virtual time. If ``auto`` is specified 4478 then the virtual cpu speed will be automatically adjusted to keep 4479 virtual time within a few seconds of real time. 4480 4481 Note that while this option can give deterministic behavior, it does 4482 not provide cycle accurate emulation. Modern CPUs contain 4483 superscalar out of order cores with complex cache hierarchies. The 4484 number of instructions executed often has little or no correlation 4485 with actual performance. 4486 4487 When the virtual cpu is sleeping, the virtual time will advance at 4488 default speed unless ``sleep=on`` is specified. With 4489 ``sleep=on``, the virtual time will jump to the next timer 4490 deadline instantly whenever the virtual cpu goes to sleep mode and 4491 will not advance if no timer is enabled. This behavior gives 4492 deterministic execution times from the guest point of view. 4493 The default if icount is enabled is ``sleep=off``. 4494 ``sleep=on`` cannot be used together with either ``shift=auto`` 4495 or ``align=on``. 4496 4497 ``align=on`` will activate the delay algorithm which will try to 4498 synchronise the host clock and the virtual clock. The goal is to 4499 have a guest running at the real frequency imposed by the shift 4500 option. Whenever the guest clock is behind the host clock and if 4501 ``align=on`` is specified then we print a message to the user to 4502 inform about the delay. Currently this option does not work when 4503 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4504 shift values for which the guest clock runs ahead of the host clock. 4505 Typically this happens when the shift value is high (how high 4506 depends on the host machine). The default if icount is enabled 4507 is ``align=off``. 4508 4509 When the ``rr`` option is specified deterministic record/replay is 4510 enabled. The ``rrfile=`` option must also be provided to 4511 specify the path to the replay log. In record mode data is written 4512 to this file, and in replay mode it is read back. 4513 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4514 name. In record mode, a new VM snapshot with the given name is created 4515 at the start of execution recording. In replay mode this option 4516 specifies the snapshot name used to load the initial VM state. 4517ERST 4518 4519DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4520 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4521 " action when watchdog fires [default=reset]\n", 4522 QEMU_ARCH_ALL) 4523SRST 4524``-watchdog-action action`` 4525 The action controls what QEMU will do when the watchdog timer 4526 expires. The default is ``reset`` (forcefully reset the guest). 4527 Other possible actions are: ``shutdown`` (attempt to gracefully 4528 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4529 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4530 guest), ``debug`` (print a debug message and continue), or ``none`` 4531 (do nothing). 4532 4533 Note that the ``shutdown`` action requires that the guest responds 4534 to ACPI signals, which it may not be able to do in the sort of 4535 situations where the watchdog would have expired, and thus 4536 ``-watchdog-action shutdown`` is not recommended for production use. 4537 4538 Examples: 4539 4540 ``-device i6300esb -watchdog-action pause`` 4541 4542ERST 4543 4544DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4545 "-echr chr set terminal escape character instead of ctrl-a\n", 4546 QEMU_ARCH_ALL) 4547SRST 4548``-echr numeric_ascii_value`` 4549 Change the escape character used for switching to the monitor when 4550 using monitor and serial sharing. The default is ``0x01`` when using 4551 the ``-nographic`` option. ``0x01`` is equal to pressing 4552 ``Control-a``. You can select a different character from the ascii 4553 control keys where 1 through 26 map to Control-a through Control-z. 4554 For instance you could use the either of the following to change the 4555 escape character to Control-t. 4556 4557 ``-echr 0x14``; \ ``-echr 20`` 4558 4559ERST 4560 4561DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4562 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4563 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4564 "-incoming unix:socketpath\n" \ 4565 " prepare for incoming migration, listen on\n" \ 4566 " specified protocol and socket address\n" \ 4567 "-incoming fd:fd\n" \ 4568 "-incoming exec:cmdline\n" \ 4569 " accept incoming migration on given file descriptor\n" \ 4570 " or from given external command\n" \ 4571 "-incoming defer\n" \ 4572 " wait for the URI to be specified via migrate_incoming\n", 4573 QEMU_ARCH_ALL) 4574SRST 4575``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4576 \ 4577``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4578 Prepare for incoming migration, listen on a given tcp port. 4579 4580``-incoming unix:socketpath`` 4581 Prepare for incoming migration, listen on a given unix socket. 4582 4583``-incoming fd:fd`` 4584 Accept incoming migration from a given filedescriptor. 4585 4586``-incoming exec:cmdline`` 4587 Accept incoming migration as an output from specified external 4588 command. 4589 4590``-incoming defer`` 4591 Wait for the URI to be specified via migrate\_incoming. The monitor 4592 can be used to change settings (such as migration parameters) prior 4593 to issuing the migrate\_incoming to allow the migration to begin. 4594ERST 4595 4596DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4597 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4598SRST 4599``-only-migratable`` 4600 Only allow migratable devices. Devices will not be allowed to enter 4601 an unmigratable state. 4602ERST 4603 4604DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4605 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4606SRST 4607``-nodefaults`` 4608 Don't create default devices. Normally, QEMU sets the default 4609 devices like serial port, parallel port, virtual console, monitor 4610 device, VGA adapter, floppy and CD-ROM drive and others. The 4611 ``-nodefaults`` option will disable all those default devices. 4612ERST 4613 4614#ifndef _WIN32 4615DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4616 "-chroot dir chroot to dir just before starting the VM\n", 4617 QEMU_ARCH_ALL) 4618#endif 4619SRST 4620``-chroot dir`` 4621 Immediately before starting guest execution, chroot to the specified 4622 directory. Especially useful in combination with -runas. 4623ERST 4624 4625#ifndef _WIN32 4626DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4627 "-runas user change to user id user just before starting the VM\n" \ 4628 " user can be numeric uid:gid instead\n", 4629 QEMU_ARCH_ALL) 4630#endif 4631SRST 4632``-runas user`` 4633 Immediately before starting guest execution, drop root privileges, 4634 switching to the specified user. 4635ERST 4636 4637DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4638 "-prom-env variable=value\n" 4639 " set OpenBIOS nvram variables\n", 4640 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4641SRST 4642``-prom-env variable=value`` 4643 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4644 4645 :: 4646 4647 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4648 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4649 4650 :: 4651 4652 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4653 -prom-env 'boot-device=hd:2,\yaboot' \ 4654 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4655ERST 4656DEF("semihosting", 0, QEMU_OPTION_semihosting, 4657 "-semihosting semihosting mode\n", 4658 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4659 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4660SRST 4661``-semihosting`` 4662 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4663 4664 .. warning:: 4665 Note that this allows guest direct access to the host filesystem, so 4666 should only be used with a trusted guest OS. 4667 4668 See the -semihosting-config option documentation for further 4669 information about the facilities this enables. 4670ERST 4671DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4672 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4673 " semihosting configuration\n", 4674QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4675QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4676SRST 4677``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4678 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4679 only). 4680 4681 .. warning:: 4682 Note that this allows guest direct access to the host filesystem, so 4683 should only be used with a trusted guest OS. 4684 4685 ``target=native|gdb|auto`` 4686 Defines where the semihosting calls will be addressed, to QEMU 4687 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4688 means ``gdb`` during debug sessions and ``native`` otherwise. 4689 4690 ``chardev=str1`` 4691 Send the output to a chardev backend output for native or auto 4692 output when not in gdb 4693 4694 ``userspace=on|off`` 4695 Allows code running in guest userspace to access the semihosting 4696 interface. The default is that only privileged guest code can 4697 make semihosting calls. Note that setting ``userspace=on`` should 4698 only be used if all guest code is trusted (for example, in 4699 bare-metal test case code). 4700 4701 ``arg=str1,arg=str2,...`` 4702 Allows the user to pass input arguments, and can be used 4703 multiple times to build up a list. The old-style 4704 ``-kernel``/``-append`` method of passing a command line is 4705 still supported for backward compatibility. If both the 4706 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4707 specified, the former is passed to semihosting as it always 4708 takes precedence. 4709ERST 4710DEF("old-param", 0, QEMU_OPTION_old_param, 4711 "-old-param old param mode\n", QEMU_ARCH_ARM) 4712SRST 4713``-old-param`` 4714 Old param mode (ARM only). 4715ERST 4716 4717DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4718 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4719 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4720 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4721 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4722 " by the kernel, but typically no longer used by modern\n" \ 4723 " C library implementations.\n" \ 4724 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4725 " to elevate privileges using set*uid|gid system calls.\n" \ 4726 " The value 'children' will deny set*uid|gid system calls for\n" \ 4727 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4728 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4729 " blocking *fork and execve\n" \ 4730 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4731 QEMU_ARCH_ALL) 4732SRST 4733``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4734 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4735 filtering and 'off' will disable it. The default is 'off'. 4736 4737 ``obsolete=string`` 4738 Enable Obsolete system calls 4739 4740 ``elevateprivileges=string`` 4741 Disable set\*uid\|gid system calls 4742 4743 ``spawn=string`` 4744 Disable \*fork and execve 4745 4746 ``resourcecontrol=string`` 4747 Disable process affinity and schedular priority 4748ERST 4749 4750DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4751 "-readconfig <file>\n" 4752 " read config file\n", QEMU_ARCH_ALL) 4753SRST 4754``-readconfig file`` 4755 Read device configuration from file. This approach is useful when 4756 you want to spawn QEMU process with many command line options but 4757 you don't want to exceed the command line character limit. 4758ERST 4759 4760DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4761 "-no-user-config\n" 4762 " do not load default user-provided config files at startup\n", 4763 QEMU_ARCH_ALL) 4764SRST 4765``-no-user-config`` 4766 The ``-no-user-config`` option makes QEMU not load any of the 4767 user-provided config files on sysconfdir. 4768ERST 4769 4770DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4771 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4772 " specify tracing options\n", 4773 QEMU_ARCH_ALL) 4774SRST 4775``-trace [[enable=]pattern][,events=file][,file=file]`` 4776 .. include:: ../qemu-option-trace.rst.inc 4777 4778ERST 4779DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4780 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4781 " load a plugin\n", 4782 QEMU_ARCH_ALL) 4783SRST 4784``-plugin file=file[,argname=argvalue]`` 4785 Load a plugin. 4786 4787 ``file=file`` 4788 Load the given plugin from a shared library file. 4789 4790 ``argname=argvalue`` 4791 Argument passed to the plugin. (Can be given multiple times.) 4792ERST 4793 4794HXCOMM Internal use 4795DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4796DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4797 4798#ifdef __linux__ 4799DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4800 "-async-teardown enable asynchronous teardown\n", 4801 QEMU_ARCH_ALL) 4802#endif 4803SRST 4804``-async-teardown`` 4805 Enable asynchronous teardown. A new process called "cleanup/<QEMU_PID>" 4806 will be created at startup sharing the address space with the main qemu 4807 process, using clone. It will wait for the main qemu process to 4808 terminate completely, and then exit. 4809 This allows qemu to terminate very quickly even if the guest was 4810 huge, leaving the teardown of the address space to the cleanup 4811 process. Since the cleanup process shares the same cgroups as the 4812 main qemu process, accounting is performed correctly. This only 4813 works if the cleanup process is not forcefully killed with SIGKILL 4814 before the main qemu process has terminated completely. 4815ERST 4816 4817DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4818 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4819 " control error message format\n" 4820 " timestamp=on enables timestamps (default: off)\n" 4821 " guest-name=on enables guest name prefix but only if\n" 4822 " -name guest option is set (default: off)\n", 4823 QEMU_ARCH_ALL) 4824SRST 4825``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4826 Control error message format. 4827 4828 ``timestamp=on|off`` 4829 Prefix messages with a timestamp. Default is off. 4830 4831 ``guest-name=on|off`` 4832 Prefix messages with guest name but only if -name guest option is set 4833 otherwise the option is ignored. Default is off. 4834ERST 4835 4836DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4837 "-dump-vmstate <file>\n" 4838 " Output vmstate information in JSON format to file.\n" 4839 " Use the scripts/vmstate-static-checker.py file to\n" 4840 " check for possible regressions in migration code\n" 4841 " by comparing two such vmstate dumps.\n", 4842 QEMU_ARCH_ALL) 4843SRST 4844``-dump-vmstate file`` 4845 Dump json-encoded vmstate information for current machine type to 4846 file in file 4847ERST 4848 4849DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4850 "-enable-sync-profile\n" 4851 " enable synchronization profiling\n", 4852 QEMU_ARCH_ALL) 4853SRST 4854``-enable-sync-profile`` 4855 Enable synchronization profiling. 4856ERST 4857 4858#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 4859DEF("perfmap", 0, QEMU_OPTION_perfmap, 4860 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 4861 QEMU_ARCH_ALL) 4862SRST 4863``-perfmap`` 4864 Generate a map file for Linux perf tools that will allow basic profiling 4865 information to be broken down into basic blocks. 4866ERST 4867 4868DEF("jitdump", 0, QEMU_OPTION_jitdump, 4869 "-jitdump generate a jit-${pid}.dump file for perf\n", 4870 QEMU_ARCH_ALL) 4871SRST 4872``-jitdump`` 4873 Generate a dump file for Linux perf tools that maps basic blocks to symbol 4874 names, line numbers and JITted code. 4875ERST 4876#endif 4877 4878DEFHEADING() 4879 4880DEFHEADING(Generic object creation:) 4881 4882DEF("object", HAS_ARG, QEMU_OPTION_object, 4883 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4884 " create a new object of type TYPENAME setting properties\n" 4885 " in the order they are specified. Note that the 'id'\n" 4886 " property must be set. These objects are placed in the\n" 4887 " '/objects' path.\n", 4888 QEMU_ARCH_ALL) 4889SRST 4890``-object typename[,prop1=value1,...]`` 4891 Create a new object of type typename setting properties in the order 4892 they are specified. Note that the 'id' property must be set. These 4893 objects are placed in the '/objects' path. 4894 4895 ``-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`` 4896 Creates a memory file backend object, which can be used to back 4897 the guest RAM with huge pages. 4898 4899 The ``id`` parameter is a unique ID that will be used to 4900 reference this memory region in other parameters, e.g. ``-numa``, 4901 ``-device nvdimm``, etc. 4902 4903 The ``size`` option provides the size of the memory region, and 4904 accepts common suffixes, e.g. ``500M``. 4905 4906 The ``mem-path`` provides the path to either a shared memory or 4907 huge page filesystem mount. 4908 4909 The ``share`` boolean option determines whether the memory 4910 region is marked as private to QEMU, or shared. The latter 4911 allows a co-operating external process to access the QEMU memory 4912 region. 4913 4914 The ``share`` is also required for pvrdma devices due to 4915 limitations in the RDMA API provided by Linux. 4916 4917 Setting share=on might affect the ability to configure NUMA 4918 bindings for the memory backend under some circumstances, see 4919 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4920 source tree for additional details. 4921 4922 Setting the ``discard-data`` boolean option to on indicates that 4923 file contents can be destroyed when QEMU exits, to avoid 4924 unnecessarily flushing data to the backing file. Note that 4925 ``discard-data`` is only an optimization, and QEMU might not 4926 discard file contents if it aborts unexpectedly or is terminated 4927 using SIGKILL. 4928 4929 The ``merge`` boolean option enables memory merge, also known as 4930 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4931 the pages for memory deduplication. 4932 4933 Setting the ``dump`` boolean option to off excludes the memory 4934 from core dumps. This feature is also known as MADV\_DONTDUMP. 4935 4936 The ``prealloc`` boolean option enables memory preallocation. 4937 4938 The ``host-nodes`` option binds the memory range to a list of 4939 NUMA host nodes. 4940 4941 The ``policy`` option sets the NUMA policy to one of the 4942 following values: 4943 4944 ``default`` 4945 default host policy 4946 4947 ``preferred`` 4948 prefer the given host node list for allocation 4949 4950 ``bind`` 4951 restrict memory allocation to the given host node list 4952 4953 ``interleave`` 4954 interleave memory allocations across the given host node 4955 list 4956 4957 The ``align`` option specifies the base address alignment when 4958 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4959 ``2M``. Some backend store specified by ``mem-path`` requires an 4960 alignment different than the default one used by QEMU, eg the 4961 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4962 such cases, users can specify the required alignment via this 4963 option. 4964 4965 The ``pmem`` option specifies whether the backing file specified 4966 by ``mem-path`` is in host persistent memory that can be 4967 accessed using the SNIA NVM programming model (e.g. Intel 4968 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4969 operations to guarantee the persistence of its own writes to 4970 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4971 migration). Also, we will map the backend-file with MAP\_SYNC 4972 flag, which ensures the file metadata is in sync for 4973 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4974 requires support from both the host kernel (since Linux kernel 4975 4.15) and the filesystem of ``mem-path`` mounted with DAX 4976 option. 4977 4978 The ``readonly`` option specifies whether the backing file is opened 4979 read-only or read-write (default). 4980 4981 ``-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`` 4982 Creates a memory backend object, which can be used to back the 4983 guest RAM. Memory backend objects offer more control than the 4984 ``-m`` option that is traditionally used to define guest RAM. 4985 Please refer to ``memory-backend-file`` for a description of the 4986 options. 4987 4988 ``-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`` 4989 Creates an anonymous memory file backend object, which allows 4990 QEMU to share the memory with an external process (e.g. when 4991 using vhost-user). The memory is allocated with memfd and 4992 optional sealing. (Linux only) 4993 4994 The ``seal`` option creates a sealed-file, that will block 4995 further resizing the memory ('on' by default). 4996 4997 The ``hugetlb`` option specify the file to be created resides in 4998 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4999 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5000 the hugetlb page size on systems that support multiple hugetlb 5001 page sizes (it must be a power of 2 value supported by the 5002 system). 5003 5004 In some versions of Linux, the ``hugetlb`` option is 5005 incompatible with the ``seal`` option (requires at least Linux 5006 4.16). 5007 5008 Please refer to ``memory-backend-file`` for a description of the 5009 other options. 5010 5011 The ``share`` boolean option is on by default with memfd. 5012 5013 ``-object rng-builtin,id=id`` 5014 Creates a random number generator backend which obtains entropy 5015 from QEMU builtin functions. The ``id`` parameter is a unique ID 5016 that will be used to reference this entropy backend from the 5017 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5018 uses this RNG backend. 5019 5020 ``-object rng-random,id=id,filename=/dev/random`` 5021 Creates a random number generator backend which obtains entropy 5022 from a device on the host. The ``id`` parameter is a unique ID 5023 that will be used to reference this entropy backend from the 5024 ``virtio-rng`` device. The ``filename`` parameter specifies 5025 which file to obtain entropy from and if omitted defaults to 5026 ``/dev/urandom``. 5027 5028 ``-object rng-egd,id=id,chardev=chardevid`` 5029 Creates a random number generator backend which obtains entropy 5030 from an external daemon running on the host. The ``id`` 5031 parameter is a unique ID that will be used to reference this 5032 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5033 parameter is the unique ID of a character device backend that 5034 provides the connection to the RNG daemon. 5035 5036 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5037 Creates a TLS anonymous credentials object, which can be used to 5038 provide TLS support on network backends. The ``id`` parameter is 5039 a unique ID which network backends will use to access the 5040 credentials. The ``endpoint`` is either ``server`` or ``client`` 5041 depending on whether the QEMU network backend that uses the 5042 credentials will be acting as a client or as a server. If 5043 ``verify-peer`` is enabled (the default) then once the handshake 5044 is completed, the peer credentials will be verified, though this 5045 is a no-op for anonymous credentials. 5046 5047 The dir parameter tells QEMU where to find the credential files. 5048 For server endpoints, this directory may contain a file 5049 dh-params.pem providing diffie-hellman parameters to use for the 5050 TLS server. If the file is missing, QEMU will generate a set of 5051 DH parameters at startup. This is a computationally expensive 5052 operation that consumes random pool entropy, so it is 5053 recommended that a persistent set of parameters be generated 5054 upfront and saved. 5055 5056 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5057 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5058 can be used to provide TLS support on network backends. The 5059 ``id`` parameter is a unique ID which network backends will use 5060 to access the credentials. The ``endpoint`` is either ``server`` 5061 or ``client`` depending on whether the QEMU network backend that 5062 uses the credentials will be acting as a client or as a server. 5063 For clients only, ``username`` is the username which will be 5064 sent to the server. If omitted it defaults to "qemu". 5065 5066 The dir parameter tells QEMU where to find the keys file. It is 5067 called "dir/keys.psk" and contains "username:key" pairs. This 5068 file can most easily be created using the GnuTLS ``psktool`` 5069 program. 5070 5071 For server endpoints, dir may also contain a file dh-params.pem 5072 providing diffie-hellman parameters to use for the TLS server. 5073 If the file is missing, QEMU will generate a set of DH 5074 parameters at startup. This is a computationally expensive 5075 operation that consumes random pool entropy, so it is 5076 recommended that a persistent set of parameters be generated up 5077 front and saved. 5078 5079 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5080 Creates a TLS anonymous credentials object, which can be used to 5081 provide TLS support on network backends. The ``id`` parameter is 5082 a unique ID which network backends will use to access the 5083 credentials. The ``endpoint`` is either ``server`` or ``client`` 5084 depending on whether the QEMU network backend that uses the 5085 credentials will be acting as a client or as a server. If 5086 ``verify-peer`` is enabled (the default) then once the handshake 5087 is completed, the peer credentials will be verified. With x509 5088 certificates, this implies that the clients must be provided 5089 with valid client certificates too. 5090 5091 The dir parameter tells QEMU where to find the credential files. 5092 For server endpoints, this directory may contain a file 5093 dh-params.pem providing diffie-hellman parameters to use for the 5094 TLS server. If the file is missing, QEMU will generate a set of 5095 DH parameters at startup. This is a computationally expensive 5096 operation that consumes random pool entropy, so it is 5097 recommended that a persistent set of parameters be generated 5098 upfront and saved. 5099 5100 For x509 certificate credentials the directory will contain 5101 further files providing the x509 certificates. The certificates 5102 must be stored in PEM format, in filenames ca-cert.pem, 5103 ca-crl.pem (optional), server-cert.pem (only servers), 5104 server-key.pem (only servers), client-cert.pem (only clients), 5105 and client-key.pem (only clients). 5106 5107 For the server-key.pem and client-key.pem files which contain 5108 sensitive private keys, it is possible to use an encrypted 5109 version by providing the passwordid parameter. This provides the 5110 ID of a previously created ``secret`` object containing the 5111 password for decryption. 5112 5113 The priority parameter allows to override the global default 5114 priority used by gnutls. This can be useful if the system 5115 administrator needs to use a weaker set of crypto priorities for 5116 QEMU without potentially forcing the weakness onto all 5117 applications. Or conversely if one wants wants a stronger 5118 default for QEMU than for all other applications, they can do 5119 this through this parameter. Its format is a gnutls priority 5120 string as described at 5121 https://gnutls.org/manual/html_node/Priority-Strings.html. 5122 5123 ``-object tls-cipher-suites,id=id,priority=priority`` 5124 Creates a TLS cipher suites object, which can be used to control 5125 the TLS cipher/protocol algorithms that applications are permitted 5126 to use. 5127 5128 The ``id`` parameter is a unique ID which frontends will use to 5129 access the ordered list of permitted TLS cipher suites from the 5130 host. 5131 5132 The ``priority`` parameter allows to override the global default 5133 priority used by gnutls. This can be useful if the system 5134 administrator needs to use a weaker set of crypto priorities for 5135 QEMU without potentially forcing the weakness onto all 5136 applications. Or conversely if one wants wants a stronger 5137 default for QEMU than for all other applications, they can do 5138 this through this parameter. Its format is a gnutls priority 5139 string as described at 5140 https://gnutls.org/manual/html_node/Priority-Strings.html. 5141 5142 An example of use of this object is to control UEFI HTTPS Boot. 5143 The tls-cipher-suites object exposes the ordered list of permitted 5144 TLS cipher suites from the host side to the guest firmware, via 5145 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5146 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5147 guest-side TLS. 5148 5149 In the following example, the priority at which the host-side policy 5150 is retrieved is given by the ``priority`` property. 5151 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5152 refer to /etc/crypto-policies/back-ends/gnutls.config. 5153 5154 .. parsed-literal:: 5155 5156 # |qemu_system| \\ 5157 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5158 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5159 5160 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5161 Interval t can't be 0, this filter batches the packet delivery: 5162 all packets arriving in a given interval on netdev netdevid are 5163 delayed until the end of the interval. Interval is in 5164 microseconds. ``status`` is optional that indicate whether the 5165 netfilter is on (enabled) or off (disabled), the default status 5166 for netfilter will be 'on'. 5167 5168 queue all\|rx\|tx is an option that can be applied to any 5169 netfilter. 5170 5171 ``all``: the filter is attached both to the receive and the 5172 transmit queue of the netdev (default). 5173 5174 ``rx``: the filter is attached to the receive queue of the 5175 netdev, where it will receive packets sent to the netdev. 5176 5177 ``tx``: the filter is attached to the transmit queue of the 5178 netdev, where it will receive packets sent by the netdev. 5179 5180 position head\|tail\|id=<id> is an option to specify where the 5181 filter should be inserted in the filter list. It can be applied 5182 to any netfilter. 5183 5184 ``head``: the filter is inserted at the head of the filter list, 5185 before any existing filters. 5186 5187 ``tail``: the filter is inserted at the tail of the filter list, 5188 behind any existing filters (default). 5189 5190 ``id=<id>``: the filter is inserted before or behind the filter 5191 specified by <id>, see the insert option below. 5192 5193 insert behind\|before is an option to specify where to insert 5194 the new filter relative to the one specified with 5195 position=id=<id>. It can be applied to any netfilter. 5196 5197 ``before``: insert before the specified filter. 5198 5199 ``behind``: insert behind the specified filter (default). 5200 5201 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5202 filter-mirror on netdev netdevid,mirror net packet to 5203 chardevchardevid, if it has the vnet\_hdr\_support flag, 5204 filter-mirror will mirror packet with vnet\_hdr\_len. 5205 5206 ``-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]`` 5207 filter-redirector on netdev netdevid,redirect filter's net 5208 packet to chardev chardevid,and redirect indev's packet to 5209 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5210 will redirect packet with vnet\_hdr\_len. Create a 5211 filter-redirector we need to differ outdev id from indev id, id 5212 can not be the same. we can just use indev or outdev, but at 5213 least one of indev or outdev need to be specified. 5214 5215 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5216 Filter-rewriter is a part of COLO project.It will rewrite tcp 5217 packet to secondary from primary to keep secondary tcp 5218 connection,and rewrite tcp packet to primary from secondary make 5219 tcp packet can be handled by client.if it has the 5220 vnet\_hdr\_support flag, we can parse packet with vnet header. 5221 5222 usage: colo secondary: -object 5223 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5224 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5225 filter-rewriter,id=rew0,netdev=hn0,queue=all 5226 5227 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5228 Dump the network traffic on netdev dev to the file specified by 5229 filename. At most len bytes (64k by default) per packet are 5230 stored. The file format is libpcap, so it can be analyzed with 5231 tools such as tcpdump or Wireshark. 5232 5233 ``-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}]`` 5234 Colo-compare gets packet from primary\_in chardevid and 5235 secondary\_in, then compare whether the payload of primary packet 5236 and secondary packet are the same. If same, it will output 5237 primary packet to out\_dev, else it will notify COLO-framework to do 5238 checkpoint and send primary packet to out\_dev. In order to 5239 improve efficiency, we need to put the task of comparison in 5240 another iothread. If it has the vnet\_hdr\_support flag, 5241 colo compare will send/recv packet with vnet\_hdr\_len. 5242 The compare\_timeout=@var{ms} determines the maximum time of the 5243 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5244 is to set the period of scanning expired primary node network packets. 5245 The max\_queue\_size=@var{size} is to set the max compare queue 5246 size depend on user environment. 5247 If user want to use Xen COLO, need to add the notify\_dev to 5248 notify Xen colo-frame to do checkpoint. 5249 5250 COLO-compare must be used with the help of filter-mirror, 5251 filter-redirector and filter-rewriter. 5252 5253 :: 5254 5255 KVM 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 -object iothread,id=iothread1 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 colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5271 5272 secondary: 5273 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5274 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5275 -chardev socket,id=red0,host=3.3.3.3,port=9003 5276 -chardev socket,id=red1,host=3.3.3.3,port=9004 5277 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5278 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5279 5280 5281 Xen COLO 5282 5283 primary: 5284 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5285 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5286 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5287 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5288 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5289 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5290 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5291 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5292 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5293 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5294 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5295 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5296 -object iothread,id=iothread1 5297 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5298 5299 secondary: 5300 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5301 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5302 -chardev socket,id=red0,host=3.3.3.3,port=9003 5303 -chardev socket,id=red1,host=3.3.3.3,port=9004 5304 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5305 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5306 5307 If you want to know the detail of above command line, you can 5308 read the colo-compare git log. 5309 5310 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5311 Creates a cryptodev backend which executes crypto operations from 5312 the QEMU cipher APIs. The id parameter is a unique ID that will 5313 be used to reference this cryptodev backend from the 5314 ``virtio-crypto`` device. The queues parameter is optional, 5315 which specify the queue number of cryptodev backend, the default 5316 of queues is 1. 5317 5318 .. parsed-literal:: 5319 5320 # |qemu_system| \\ 5321 [...] \\ 5322 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5323 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5324 [...] 5325 5326 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5327 Creates a vhost-user cryptodev backend, backed by a chardev 5328 chardevid. The id parameter is a unique ID that will be used to 5329 reference this cryptodev backend from the ``virtio-crypto`` 5330 device. The chardev should be a unix domain socket backed one. 5331 The vhost-user uses a specifically defined protocol to pass 5332 vhost ioctl replacement messages to an application on the other 5333 end of the socket. The queues parameter is optional, which 5334 specify the queue number of cryptodev backend for multiqueue 5335 vhost-user, the default of queues is 1. 5336 5337 .. parsed-literal:: 5338 5339 # |qemu_system| \\ 5340 [...] \\ 5341 -chardev socket,id=chardev0,path=/path/to/socket \\ 5342 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5343 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5344 [...] 5345 5346 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5347 \ 5348 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5349 Defines a secret to store a password, encryption key, or some 5350 other sensitive data. The sensitive data can either be passed 5351 directly via the data parameter, or indirectly via the file 5352 parameter. Using the data parameter is insecure unless the 5353 sensitive data is encrypted. 5354 5355 The sensitive data can be provided in raw format (the default), 5356 or base64. When encoded as JSON, the raw format only supports 5357 valid UTF-8 characters, so base64 is recommended for sending 5358 binary data. QEMU will convert from which ever format is 5359 provided to the format it needs internally. eg, an RBD password 5360 can be provided in raw format, even though it will be base64 5361 encoded when passed onto the RBD sever. 5362 5363 For added protection, it is possible to encrypt the data 5364 associated with a secret using the AES-256-CBC cipher. Use of 5365 encryption is indicated by providing the keyid and iv 5366 parameters. The keyid parameter provides the ID of a previously 5367 defined secret that contains the AES-256 decryption key. This 5368 key should be 32-bytes long and be base64 encoded. The iv 5369 parameter provides the random initialization vector used for 5370 encryption of this particular secret and should be a base64 5371 encrypted string of the 16-byte IV. 5372 5373 The simplest (insecure) usage is to provide the secret inline 5374 5375 .. parsed-literal:: 5376 5377 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5378 5379 The simplest secure usage is to provide the secret via a file 5380 5381 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5382 secret,id=sec0,file=mypasswd.txt,format=raw 5383 5384 For greater security, AES-256-CBC should be used. To illustrate 5385 usage, consider the openssl command line tool which can encrypt 5386 the data. Note that when encrypting, the plaintext must be 5387 padded to the cipher block size (32 bytes) using the standard 5388 PKCS#5/6 compatible padding algorithm. 5389 5390 First a master key needs to be created in base64 encoding: 5391 5392 :: 5393 5394 # openssl rand -base64 32 > key.b64 5395 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5396 5397 Each secret to be encrypted needs to have a random 5398 initialization vector generated. These do not need to be kept 5399 secret 5400 5401 :: 5402 5403 # openssl rand -base64 16 > iv.b64 5404 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5405 5406 The secret to be defined can now be encrypted, in this case 5407 we're telling openssl to base64 encode the result, but it could 5408 be left as raw bytes if desired. 5409 5410 :: 5411 5412 # SECRET=$(printf "letmein" | 5413 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5414 5415 When launching QEMU, create a master secret pointing to 5416 ``key.b64`` and specify that to be used to decrypt the user 5417 password. Pass the contents of ``iv.b64`` to the second secret 5418 5419 .. parsed-literal:: 5420 5421 # |qemu_system| \\ 5422 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5423 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5424 data=$SECRET,iv=$(<iv.b64) 5425 5426 ``-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]`` 5427 Create a Secure Encrypted Virtualization (SEV) guest object, 5428 which can be used to provide the guest memory encryption support 5429 on AMD processors. 5430 5431 When memory encryption is enabled, one of the physical address 5432 bit (aka the C-bit) is utilized to mark if a memory page is 5433 protected. The ``cbitpos`` is used to provide the C-bit 5434 position. The C-bit position is Host family dependent hence user 5435 must provide this value. On EPYC, the value should be 47. 5436 5437 When memory encryption is enabled, we loose certain bits in 5438 physical address space. The ``reduced-phys-bits`` is used to 5439 provide the number of bits we loose in physical address space. 5440 Similar to C-bit, the value is Host family dependent. On EPYC, 5441 the value should be 5. 5442 5443 The ``sev-device`` provides the device file to use for 5444 communicating with the SEV firmware running inside AMD Secure 5445 Processor. The default device is '/dev/sev'. If hardware 5446 supports memory encryption then /dev/sev devices are created by 5447 CCP driver. 5448 5449 The ``policy`` provides the guest policy to be enforced by the 5450 SEV firmware and restrict what configuration and operational 5451 commands can be performed on this guest by the hypervisor. The 5452 policy should be provided by the guest owner and is bound to the 5453 guest and cannot be changed throughout the lifetime of the 5454 guest. The default is 0. 5455 5456 If guest ``policy`` allows sharing the key with another SEV 5457 guest then ``handle`` can be use to provide handle of the guest 5458 from which to share the key. 5459 5460 The ``dh-cert-file`` and ``session-file`` provides the guest 5461 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5462 and session parameters are used for establishing a cryptographic 5463 session with the guest owner to negotiate keys used for 5464 attestation. The file must be encoded in base64. 5465 5466 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5467 cmdline to a designated guest firmware page for measured Linux 5468 boot with -kernel. The default is off. (Since 6.2) 5469 5470 e.g to launch a SEV guest 5471 5472 .. parsed-literal:: 5473 5474 # |qemu_system_x86| \\ 5475 ...... \\ 5476 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5477 -machine ...,memory-encryption=sev0 \\ 5478 ..... 5479 5480 ``-object authz-simple,id=id,identity=string`` 5481 Create an authorization object that will control access to 5482 network services. 5483 5484 The ``identity`` parameter is identifies the user and its format 5485 depends on the network service that authorization object is 5486 associated with. For authorizing based on TLS x509 certificates, 5487 the identity must be the x509 distinguished name. Note that care 5488 must be taken to escape any commas in the distinguished name. 5489 5490 An example authorization object to validate a x509 distinguished 5491 name would look like: 5492 5493 .. parsed-literal:: 5494 5495 # |qemu_system| \\ 5496 ... \\ 5497 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5498 ... 5499 5500 Note the use of quotes due to the x509 distinguished name 5501 containing whitespace, and escaping of ','. 5502 5503 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5504 Create an authorization object that will control access to 5505 network services. 5506 5507 The ``filename`` parameter is the fully qualified path to a file 5508 containing the access control list rules in JSON format. 5509 5510 An example set of rules that match against SASL usernames might 5511 look like: 5512 5513 :: 5514 5515 { 5516 "rules": [ 5517 { "match": "fred", "policy": "allow", "format": "exact" }, 5518 { "match": "bob", "policy": "allow", "format": "exact" }, 5519 { "match": "danb", "policy": "deny", "format": "glob" }, 5520 { "match": "dan*", "policy": "allow", "format": "exact" }, 5521 ], 5522 "policy": "deny" 5523 } 5524 5525 When checking access the object will iterate over all the rules 5526 and the first rule to match will have its ``policy`` value 5527 returned as the result. If no rules match, then the default 5528 ``policy`` value is returned. 5529 5530 The rules can either be an exact string match, or they can use 5531 the simple UNIX glob pattern matching to allow wildcards to be 5532 used. 5533 5534 If ``refresh`` is set to true the file will be monitored and 5535 automatically reloaded whenever its content changes. 5536 5537 As with the ``authz-simple`` object, the format of the identity 5538 strings being matched depends on the network service, but is 5539 usually a TLS x509 distinguished name, or a SASL username. 5540 5541 An example authorization object to validate a SASL username 5542 would look like: 5543 5544 .. parsed-literal:: 5545 5546 # |qemu_system| \\ 5547 ... \\ 5548 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5549 ... 5550 5551 ``-object authz-pam,id=id,service=string`` 5552 Create an authorization object that will control access to 5553 network services. 5554 5555 The ``service`` parameter provides the name of a PAM service to 5556 use for authorization. It requires that a file 5557 ``/etc/pam.d/service`` exist to provide the configuration for 5558 the ``account`` subsystem. 5559 5560 An example authorization object to validate a TLS x509 5561 distinguished name would look like: 5562 5563 .. parsed-literal:: 5564 5565 # |qemu_system| \\ 5566 ... \\ 5567 -object authz-pam,id=auth0,service=qemu-vnc \\ 5568 ... 5569 5570 There would then be a corresponding config file for PAM at 5571 ``/etc/pam.d/qemu-vnc`` that contains: 5572 5573 :: 5574 5575 account requisite pam_listfile.so item=user sense=allow \ 5576 file=/etc/qemu/vnc.allow 5577 5578 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5579 of x509 distinguished names that are permitted access 5580 5581 :: 5582 5583 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5584 5585 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5586 Creates a dedicated event loop thread that devices can be 5587 assigned to. This is known as an IOThread. By default device 5588 emulation happens in vCPU threads or the main event loop thread. 5589 This can become a scalability bottleneck. IOThreads allow device 5590 emulation and I/O to run on other host CPUs. 5591 5592 The ``id`` parameter is a unique ID that will be used to 5593 reference this IOThread from ``-device ...,iothread=id``. 5594 Multiple devices can be assigned to an IOThread. Note that not 5595 all devices support an ``iothread`` parameter. 5596 5597 The ``query-iothreads`` QMP command lists IOThreads and reports 5598 their thread IDs so that the user can configure host CPU 5599 pinning/affinity. 5600 5601 IOThreads use an adaptive polling algorithm to reduce event loop 5602 latency. Instead of entering a blocking system call to monitor 5603 file descriptors and then pay the cost of being woken up when an 5604 event occurs, the polling algorithm spins waiting for events for 5605 a short time. The algorithm's default parameters are suitable 5606 for many cases but can be adjusted based on knowledge of the 5607 workload and/or host device latency. 5608 5609 The ``poll-max-ns`` parameter is the maximum number of 5610 nanoseconds to busy wait for events. Polling can be disabled by 5611 setting this value to 0. 5612 5613 The ``poll-grow`` parameter is the multiplier used to increase 5614 the polling time when the algorithm detects it is missing events 5615 due to not polling long enough. 5616 5617 The ``poll-shrink`` parameter is the divisor used to decrease 5618 the polling time when the algorithm detects it is spending too 5619 long polling without encountering events. 5620 5621 The ``aio-max-batch`` parameter is the maximum number of requests 5622 in a batch for the AIO engine, 0 means that the engine will use 5623 its default. 5624 5625 The IOThread parameters can be modified at run-time using the 5626 ``qom-set`` command (where ``iothread1`` is the IOThread's 5627 ``id``): 5628 5629 :: 5630 5631 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5632ERST 5633 5634 5635HXCOMM This is the last statement. Insert new options before this line! 5636 5637#undef DEF 5638#undef DEFHEADING 5639#undef ARCHHEADING 5640
