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 QEMU_ARCH_ALL) 41SRST 42``-machine [type=]name[,prop=value[,...]]`` 43 Select the emulated machine by name. Use ``-machine help`` to list 44 available machines. 45 46 For architectures which aim to support live migration compatibility 47 across releases, each release will introduce a new versioned machine 48 type. For example, the 2.8.0 release introduced machine types 49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 50 51 To allow live migration of guests from QEMU version 2.8.0, to QEMU 52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 54 skip multiple intermediate releases when upgrading, new releases of 55 QEMU will support machine types from many previous versions. 56 57 Supported machine properties are: 58 59 ``accel=accels1[:accels2[:...]]`` 60 This is used to enable an accelerator. Depending on the target 61 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 62 By default, tcg is used. If there is more than one accelerator 63 specified, the next one is used if the previous one fails to 64 initialize. 65 66 ``vmport=on|off|auto`` 67 Enables emulation of VMWare IO port, for vmmouse etc. auto says 68 to select the value based on accel. For accel=xen the default is 69 off otherwise the default is on. 70 71 ``dump-guest-core=on|off`` 72 Include guest memory in a core dump. The default is on. 73 74 ``mem-merge=on|off`` 75 Enables or disables memory merge support. This feature, when 76 supported by the host, de-duplicates identical memory pages 77 among VMs instances (enabled by default). 78 79 ``aes-key-wrap=on|off`` 80 Enables or disables AES key wrapping support on s390-ccw hosts. 81 This feature controls whether AES wrapping keys will be created 82 to allow execution of AES cryptographic functions. The default 83 is on. 84 85 ``dea-key-wrap=on|off`` 86 Enables or disables DEA key wrapping support on s390-ccw hosts. 87 This feature controls whether DEA wrapping keys will be created 88 to allow execution of DEA cryptographic functions. The default 89 is on. 90 91 ``nvdimm=on|off`` 92 Enables or disables NVDIMM support. The default is off. 93 94 ``memory-encryption=`` 95 Memory encryption object to use. The default is none. 96 97 ``hmat=on|off`` 98 Enables or disables ACPI Heterogeneous Memory Attribute Table 99 (HMAT) support. The default is off. 100 101 ``memory-backend='id'`` 102 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 103 Allows to use a memory backend as main RAM. 104 105 For example: 106 :: 107 108 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 109 -machine memory-backend=pc.ram 110 -m 512M 111 112 Migration compatibility note: 113 114 * as backend id one shall use value of 'default-ram-id', advertised by 115 machine type (available via ``query-machines`` QMP command), if migration 116 to/from old QEMU (<5.0) is expected. 117 * for machine types 4.0 and older, user shall 118 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 119 if migration to/from old QEMU (<5.0) is expected. 120 121 For example: 122 :: 123 124 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 125 -machine memory-backend=pc.ram 126 -m 512M 127ERST 128 129DEF("M", HAS_ARG, QEMU_OPTION_M, 130 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 131 QEMU_ARCH_ALL) 132 133SRST 134``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 135 Define an SGX EPC section. 136ERST 137 138DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 139 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 140SRST 141``-cpu model`` 142 Select CPU model (``-cpu help`` for list and additional feature 143 selection) 144ERST 145 146DEF("accel", HAS_ARG, QEMU_OPTION_accel, 147 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 148 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 149 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 150 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 151 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 152 " split-wx=on|off (enable TCG split w^x mapping)\n" 153 " tb-size=n (TCG translation block cache size)\n" 154 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 155 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 156SRST 157``-accel name[,prop=value[,...]]`` 158 This is used to enable an accelerator. Depending on the target 159 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 160 default, tcg is used. If there is more than one accelerator 161 specified, the next one is used if the previous one fails to 162 initialize. 163 164 ``igd-passthru=on|off`` 165 When Xen is in use, this option controls whether Intel 166 integrated graphics devices can be passed through to the guest 167 (default=off) 168 169 ``kernel-irqchip=on|off|split`` 170 Controls KVM in-kernel irqchip support. The default is full 171 acceleration of the interrupt controllers. On x86, split irqchip 172 reduces the kernel attack surface, at a performance cost for 173 non-MSI interrupts. Disabling the in-kernel irqchip completely 174 is not recommended except for debugging purposes. 175 176 ``kvm-shadow-mem=size`` 177 Defines the size of the KVM shadow MMU. 178 179 ``split-wx=on|off`` 180 Controls the use of split w^x mapping for the TCG code generation 181 buffer. Some operating systems require this to be enabled, and in 182 such a case this will default on. On other operating systems, this 183 will default off, but one may enable this for testing or debugging. 184 185 ``tb-size=n`` 186 Controls the size (in MiB) of the TCG translation block cache. 187 188 ``thread=single|multi`` 189 Controls number of TCG threads. When the TCG is multi-threaded 190 there will be one thread per vCPU therefore taking advantage of 191 additional host cores. The default is to enable multi-threading 192 where both the back-end and front-ends support it and no 193 incompatible TCG features have been enabled (e.g. 194 icount/replay). 195 196 ``dirty-ring-size=n`` 197 When the KVM accelerator is used, it controls the size of the per-vCPU 198 dirty page ring buffer (number of entries for each vCPU). It should 199 be a value that is power of two, and it should be 1024 or bigger (but 200 still less than the maximum value that the kernel supports). 4096 201 could be a good initial value if you have no idea which is the best. 202 Set this value to 0 to disable the feature. By default, this feature 203 is disabled (dirty-ring-size=0). When enabled, KVM will instead 204 record dirty pages in a bitmap. 205 206ERST 207 208DEF("smp", HAS_ARG, QEMU_OPTION_smp, 209 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 210 " set the number of initial CPUs to 'n' [default=1]\n" 211 " maxcpus= maximum number of total CPUs, including\n" 212 " offline CPUs for hotplug, etc\n" 213 " sockets= number of sockets on the machine board\n" 214 " dies= number of dies in one socket\n" 215 " clusters= number of clusters in one die\n" 216 " cores= number of cores in one cluster\n" 217 " threads= number of threads in one core\n" 218 "Note: Different machines may have different subsets of the CPU topology\n" 219 " parameters supported, so the actual meaning of the supported parameters\n" 220 " will vary accordingly. For example, for a machine type that supports a\n" 221 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 222 " sequentially mean as below:\n" 223 " sockets means the number of sockets on the machine board\n" 224 " cores means the number of cores in one socket\n" 225 " threads means the number of threads in one core\n" 226 " For a particular machine type board, an expected CPU topology hierarchy\n" 227 " can be defined through the supported sub-option. Unsupported parameters\n" 228 " can also be provided in addition to the sub-option, but their values\n" 229 " must be set as 1 in the purpose of correct parsing.\n", 230 QEMU_ARCH_ALL) 231SRST 232``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 233 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 234 the machine type board. On boards supporting CPU hotplug, the optional 235 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 236 added at runtime. When both parameters are omitted, the maximum number 237 of CPUs will be calculated from the provided topology members and the 238 initial CPU count will match the maximum number. When only one of them 239 is given then the omitted one will be set to its counterpart's value. 240 Both parameters may be specified, but the maximum number of CPUs must 241 be equal to or greater than the initial CPU count. Product of the 242 CPU topology hierarchy must be equal to the maximum number of CPUs. 243 Both parameters are subject to an upper limit that is determined by 244 the specific machine type chosen. 245 246 To control reporting of CPU topology information, values of the topology 247 parameters can be specified. Machines may only support a subset of the 248 parameters and different machines may have different subsets supported 249 which vary depending on capacity of the corresponding CPU targets. So 250 for a particular machine type board, an expected topology hierarchy can 251 be defined through the supported sub-option. Unsupported parameters can 252 also be provided in addition to the sub-option, but their values must be 253 set as 1 in the purpose of correct parsing. 254 255 Either the initial CPU count, or at least one of the topology parameters 256 must be specified. The specified parameters must be greater than zero, 257 explicit configuration like "cpus=0" is not allowed. Values for any 258 omitted parameters will be computed from those which are given. 259 260 For example, the following sub-option defines a CPU topology hierarchy 261 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 262 core) for a machine that only supports sockets/cores/threads. 263 Some members of the option can be omitted but their values will be 264 automatically computed: 265 266 :: 267 268 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 269 270 The following sub-option defines a CPU topology hierarchy (2 sockets 271 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 272 per core) for PC machines which support sockets/dies/cores/threads. 273 Some members of the option can be omitted but their values will be 274 automatically computed: 275 276 :: 277 278 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 279 280 The following sub-option defines a CPU topology hierarchy (2 sockets 281 totally on the machine, 2 clusters per socket, 2 cores per cluster, 282 2 threads per core) for ARM virt machines which support sockets/clusters 283 /cores/threads. Some members of the option can be omitted but their values 284 will be automatically computed: 285 286 :: 287 288 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 289 290 Historically preference was given to the coarsest topology parameters 291 when computing missing values (ie sockets preferred over cores, which 292 were preferred over threads), however, this behaviour is considered 293 liable to change. Prior to 6.2 the preference was sockets over cores 294 over threads. Since 6.2 the preference is cores over sockets over threads. 295 296 For example, the following option defines a machine board with 2 sockets 297 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 298 299 :: 300 301 -smp 2 302ERST 303 304DEF("numa", HAS_ARG, QEMU_OPTION_numa, 305 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 306 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 307 "-numa dist,src=source,dst=destination,val=distance\n" 308 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 309 "-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" 310 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 311 QEMU_ARCH_ALL) 312SRST 313``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 314 \ 315``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 316 \ 317``-numa dist,src=source,dst=destination,val=distance`` 318 \ 319``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 320 \ 321``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 322 \ 323``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 324 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 325 distance from a source node to a destination node. Set the ACPI 326 Heterogeneous Memory Attributes for the given nodes. 327 328 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 329 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 330 contiguous range of CPU indexes (or a single VCPU if lastcpu is 331 omitted). A non-contiguous set of VCPUs can be represented by 332 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 333 omitted on all nodes, VCPUs are automatically split between them. 334 335 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 336 NUMA node: 337 338 :: 339 340 -numa node,cpus=0-2,cpus=5 341 342 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 343 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 344 assign CPU objects to a node using topology layout properties of 345 CPU. The set of properties is machine specific, and depends on used 346 machine type/'\ ``smp``\ ' options. It could be queried with 347 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 348 property specifies node to which CPU object will be assigned, it's 349 required for node to be declared with '\ ``node``\ ' option before 350 it's used with '\ ``cpu``\ ' option. 351 352 For example: 353 354 :: 355 356 -M pc \ 357 -smp 1,sockets=2,maxcpus=2 \ 358 -numa node,nodeid=0 -numa node,nodeid=1 \ 359 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 360 361 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 362 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 363 a given memory backend device to a node. If '\ ``mem``\ ' and 364 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 365 366 367 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 368 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 369 use it. 370 371 '\ ``initiator``\ ' is an additional option that points to an 372 initiator NUMA node that has best performance (the lowest latency or 373 largest bandwidth) to this NUMA node. Note that this option can be 374 set only when the machine property 'hmat' is set to 'on'. 375 376 Following example creates a machine with 2 NUMA nodes, node 0 has 377 CPU. node 1 has only memory, and its initiator is node 0. Note that 378 because node 0 has CPU, by default the initiator of node 0 is itself 379 and must be itself. 380 381 :: 382 383 -machine hmat=on \ 384 -m 2G,slots=2,maxmem=4G \ 385 -object memory-backend-ram,size=1G,id=m0 \ 386 -object memory-backend-ram,size=1G,id=m1 \ 387 -numa node,nodeid=0,memdev=m0 \ 388 -numa node,nodeid=1,memdev=m1,initiator=0 \ 389 -smp 2,sockets=2,maxcpus=2 \ 390 -numa cpu,node-id=0,socket-id=0 \ 391 -numa cpu,node-id=0,socket-id=1 392 393 source and destination are NUMA node IDs. distance is the NUMA 394 distance from source to destination. The distance from a node to 395 itself is always 10. If any pair of nodes is given a distance, then 396 all pairs must be given distances. Although, when distances are only 397 given in one direction for each pair of nodes, then the distances in 398 the opposite directions are assumed to be the same. If, however, an 399 asymmetrical pair of distances is given for even one node pair, then 400 all node pairs must be provided distance values for both directions, 401 even when they are symmetrical. When a node is unreachable from 402 another node, set the pair's distance to 255. 403 404 Note that the -``numa`` option doesn't allocate any of the specified 405 resources, it just assigns existing resources to NUMA nodes. This 406 means that one still has to use the ``-m``, ``-smp`` options to 407 allocate RAM and VCPUs respectively. 408 409 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 410 Information between initiator and target NUMA nodes in ACPI 411 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 412 create memory requests, usually it has one or more processors. 413 Target NUMA node contains addressable memory. 414 415 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 416 the memory hierarchy of the target NUMA node: if hierarchy is 417 'memory', the structure represents the memory performance; if 418 hierarchy is 'first-level\|second-level\|third-level', this 419 structure represents aggregated performance of memory side caches 420 for each domain. type of 'data-type' is type of data represented by 421 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 422 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 423 the target memory; if 'hierarchy' is 424 'first-level\|second-level\|third-level', 'data-type' is 425 'access\|read\|write' hit latency or 'access\|read\|write' hit 426 bandwidth of the target memory side cache. 427 428 lat is latency value in nanoseconds. bw is bandwidth value, the 429 possible value and units are NUM[M\|G\|T], mean that the bandwidth 430 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 431 used suffix). Note that if latency or bandwidth value is 0, means 432 the corresponding latency or bandwidth information is not provided. 433 434 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 435 belongs. size is the size of memory side cache in bytes. level is 436 the cache level described in this structure, note that the cache 437 level 0 should not be used with '\ ``hmat-cache``\ ' option. 438 associativity is the cache associativity, the possible value is 439 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 440 is the write policy. line is the cache Line size in bytes. 441 442 For example, the following options describe 2 NUMA nodes. Node 0 has 443 2 cpus and a ram, node 1 has only a ram. The processors in node 0 444 access memory in node 0 with access-latency 5 nanoseconds, 445 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 446 memory in NUMA node 1 with access-latency 10 nanoseconds, 447 access-bandwidth is 100 MB/s. And for memory side cache information, 448 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 449 policy is write-back, the cache Line size is 8 bytes: 450 451 :: 452 453 -machine hmat=on \ 454 -m 2G \ 455 -object memory-backend-ram,size=1G,id=m0 \ 456 -object memory-backend-ram,size=1G,id=m1 \ 457 -smp 2,sockets=2,maxcpus=2 \ 458 -numa node,nodeid=0,memdev=m0 \ 459 -numa node,nodeid=1,memdev=m1,initiator=0 \ 460 -numa cpu,node-id=0,socket-id=0 \ 461 -numa cpu,node-id=0,socket-id=1 \ 462 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 463 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 464 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 465 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 466 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 467 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 468ERST 469 470DEF("cxl-fixed-memory-window", HAS_ARG, QEMU_OPTION_cxl_fixed_memory_window, 471 "-cxl-fixed-memory-window targets.0=firsttarget,targets.1=secondtarget,size=size[,interleave-granularity=granularity]\n", 472 QEMU_ARCH_ALL) 473SRST 474``-cxl-fixed-memory-window targets.0=firsttarget,targets.1=secondtarget,size=size[,interleave-granularity=granularity]`` 475 Define a CXL Fixed Memory Window (CFMW). 476 477 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 478 479 They are regions of Host Physical Addresses (HPA) on a system which 480 may be interleaved across one or more CXL host bridges. The system 481 software will assign particular devices into these windows and 482 configure the downstream Host-managed Device Memory (HDM) decoders 483 in root ports, switch ports and devices appropriately to meet the 484 interleave requirements before enabling the memory devices. 485 486 ``targets.X=firsttarget`` provides the mapping to CXL host bridges 487 which may be identified by the id provied in the -device entry. 488 Multiple entries are needed to specify all the targets when 489 the fixed memory window represents interleaved memory. X is the 490 target index from 0. 491 492 ``size=size`` sets the size of the CFMW. This must be a multiple of 493 256MiB. The region will be aligned to 256MiB but the location is 494 platform and configuration dependent. 495 496 ``interleave-granularity=granularity`` sets the granularity of 497 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 498 4096KiB, 8192KiB and 16384KiB granularities supported. 499 500 Example: 501 502 :: 503 504 -cxl-fixed-memory-window targets.0=cxl.0,targets.1=cxl.1,size=128G,interleave-granularity=512k 505 506ERST 507 508DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 509 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 510 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 511SRST 512``-add-fd fd=fd,set=set[,opaque=opaque]`` 513 Add a file descriptor to an fd set. Valid options are: 514 515 ``fd=fd`` 516 This option defines the file descriptor of which a duplicate is 517 added to fd set. The file descriptor cannot be stdin, stdout, or 518 stderr. 519 520 ``set=set`` 521 This option defines the ID of the fd set to add the file 522 descriptor to. 523 524 ``opaque=opaque`` 525 This option defines a free-form string that can be used to 526 describe fd. 527 528 You can open an image using pre-opened file descriptors from an fd 529 set: 530 531 .. parsed-literal:: 532 533 |qemu_system| \\ 534 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 535 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 536 -drive file=/dev/fdset/2,index=0,media=disk 537ERST 538 539DEF("set", HAS_ARG, QEMU_OPTION_set, 540 "-set group.id.arg=value\n" 541 " set <arg> parameter for item <id> of type <group>\n" 542 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 543SRST 544``-set group.id.arg=value`` 545 Set parameter arg for item id of type group 546ERST 547 548DEF("global", HAS_ARG, QEMU_OPTION_global, 549 "-global driver.property=value\n" 550 "-global driver=driver,property=property,value=value\n" 551 " set a global default for a driver property\n", 552 QEMU_ARCH_ALL) 553SRST 554``-global driver.prop=value`` 555 \ 556``-global driver=driver,property=property,value=value`` 557 Set default value of driver's property prop to value, e.g.: 558 559 .. parsed-literal:: 560 561 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 562 563 In particular, you can use this to set driver properties for devices 564 which are created automatically by the machine model. To create a 565 device which is not created automatically and set properties on it, 566 use -``device``. 567 568 -global driver.prop=value is shorthand for -global 569 driver=driver,property=prop,value=value. The longhand syntax works 570 even when driver contains a dot. 571ERST 572 573DEF("boot", HAS_ARG, QEMU_OPTION_boot, 574 "-boot [order=drives][,once=drives][,menu=on|off]\n" 575 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 576 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 577 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 578 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 579 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 580 QEMU_ARCH_ALL) 581SRST 582``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 583 Specify boot order drives as a string of drive letters. Valid drive 584 letters depend on the target architecture. The x86 PC uses: a, b 585 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 586 (Etherboot from network adapter 1-4), hard disk boot is the default. 587 To apply a particular boot order only on the first startup, specify 588 it via ``once``. Note that the ``order`` or ``once`` parameter 589 should not be used together with the ``bootindex`` property of 590 devices, since the firmware implementations normally do not support 591 both at the same time. 592 593 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 594 as firmware/BIOS supports them. The default is non-interactive boot. 595 596 A splash picture could be passed to bios, enabling user to show it 597 as logo, when option splash=sp\_name is given and menu=on, If 598 firmware/BIOS supports them. Currently Seabios for X86 system 599 support it. limitation: The splash file could be a jpeg file or a 600 BMP file in 24 BPP format(true color). The resolution should be 601 supported by the SVGA mode, so the recommended is 320x240, 640x480, 602 800x640. 603 604 A timeout could be passed to bios, guest will pause for rb\_timeout 605 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 606 not reboot, qemu passes '-1' to bios by default. Currently Seabios 607 for X86 system support it. 608 609 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 610 it. This only effects when boot priority is changed by bootindex 611 options. The default is non-strict boot. 612 613 .. parsed-literal:: 614 615 # try to boot from network first, then from hard disk 616 |qemu_system_x86| -boot order=nc 617 # boot from CD-ROM first, switch back to default order after reboot 618 |qemu_system_x86| -boot once=d 619 # boot with a splash picture for 5 seconds. 620 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 621 622 Note: The legacy format '-boot drives' is still supported but its 623 use is discouraged as it may be removed from future versions. 624ERST 625 626DEF("m", HAS_ARG, QEMU_OPTION_m, 627 "-m [size=]megs[,slots=n,maxmem=size]\n" 628 " configure guest RAM\n" 629 " size: initial amount of guest memory\n" 630 " slots: number of hotplug slots (default: none)\n" 631 " maxmem: maximum amount of guest memory (default: none)\n" 632 "NOTE: Some architectures might enforce a specific granularity\n", 633 QEMU_ARCH_ALL) 634SRST 635``-m [size=]megs[,slots=n,maxmem=size]`` 636 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 637 Optionally, a suffix of "M" or "G" can be used to signify a value in 638 megabytes or gigabytes respectively. Optional pair slots, maxmem 639 could be used to set amount of hotpluggable memory slots and maximum 640 amount of memory. Note that maxmem must be aligned to the page size. 641 642 For example, the following command-line sets the guest startup RAM 643 size to 1GB, creates 3 slots to hotplug additional memory and sets 644 the maximum memory the guest can reach to 4GB: 645 646 .. parsed-literal:: 647 648 |qemu_system| -m 1G,slots=3,maxmem=4G 649 650 If slots and maxmem are not specified, memory hotplug won't be 651 enabled and the guest startup RAM will never increase. 652ERST 653 654DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 655 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 656SRST 657``-mem-path path`` 658 Allocate guest RAM from a temporarily created file in path. 659ERST 660 661DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 662 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 663 QEMU_ARCH_ALL) 664SRST 665``-mem-prealloc`` 666 Preallocate memory when using -mem-path. 667ERST 668 669DEF("k", HAS_ARG, QEMU_OPTION_k, 670 "-k language use keyboard layout (for example 'fr' for French)\n", 671 QEMU_ARCH_ALL) 672SRST 673``-k language`` 674 Use keyboard layout language (for example ``fr`` for French). This 675 option is only needed where it is not easy to get raw PC keycodes 676 (e.g. on Macs, with some X11 servers or with a VNC or curses 677 display). You don't normally need to use it on PC/Linux or 678 PC/Windows hosts. 679 680 The available layouts are: 681 682 :: 683 684 ar de-ch es fo fr-ca hu ja mk no pt-br sv 685 da en-gb et fr fr-ch is lt nl pl ru th 686 de en-us fi fr-be hr it lv nl-be pt sl tr 687 688 The default is ``en-us``. 689ERST 690 691 692HXCOMM Deprecated by -audiodev 693DEF("audio-help", 0, QEMU_OPTION_audio_help, 694 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 695 QEMU_ARCH_ALL) 696SRST 697``-audio-help`` 698 Will show the -audiodev equivalent of the currently specified 699 (deprecated) environment variables. 700ERST 701 702DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 703 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 704 " specifies the audio backend to use\n" 705 " id= identifier of the backend\n" 706 " timer-period= timer period in microseconds\n" 707 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 708 " in|out.fixed-settings= use fixed settings for host audio\n" 709 " in|out.frequency= frequency to use with fixed settings\n" 710 " in|out.channels= number of channels to use with fixed settings\n" 711 " in|out.format= sample format to use with fixed settings\n" 712 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 713 " in|out.voices= number of voices to use\n" 714 " in|out.buffer-length= length of buffer in microseconds\n" 715 "-audiodev none,id=id,[,prop[=value][,...]]\n" 716 " dummy driver that discards all output\n" 717#ifdef CONFIG_AUDIO_ALSA 718 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 719 " in|out.dev= name of the audio device to use\n" 720 " in|out.period-length= length of period in microseconds\n" 721 " in|out.try-poll= attempt to use poll mode\n" 722 " threshold= threshold (in microseconds) when playback starts\n" 723#endif 724#ifdef CONFIG_AUDIO_COREAUDIO 725 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 726 " in|out.buffer-count= number of buffers\n" 727#endif 728#ifdef CONFIG_AUDIO_DSOUND 729 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 730 " latency= add extra latency to playback in microseconds\n" 731#endif 732#ifdef CONFIG_AUDIO_OSS 733 "-audiodev oss,id=id[,prop[=value][,...]]\n" 734 " in|out.dev= path of the audio device to use\n" 735 " in|out.buffer-count= number of buffers\n" 736 " in|out.try-poll= attempt to use poll mode\n" 737 " try-mmap= try using memory mapped access\n" 738 " exclusive= open device in exclusive mode\n" 739 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 740#endif 741#ifdef CONFIG_AUDIO_PA 742 "-audiodev pa,id=id[,prop[=value][,...]]\n" 743 " server= PulseAudio server address\n" 744 " in|out.name= source/sink device name\n" 745 " in|out.latency= desired latency in microseconds\n" 746#endif 747#ifdef CONFIG_AUDIO_SDL 748 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 749 " in|out.buffer-count= number of buffers\n" 750#endif 751#ifdef CONFIG_SPICE 752 "-audiodev spice,id=id[,prop[=value][,...]]\n" 753#endif 754#ifdef CONFIG_DBUS_DISPLAY 755 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 756#endif 757 "-audiodev wav,id=id[,prop[=value][,...]]\n" 758 " path= path of wav file to record\n", 759 QEMU_ARCH_ALL) 760SRST 761``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 762 Adds a new audio backend driver identified by id. There are global 763 and driver specific properties. Some values can be set differently 764 for input and output, they're marked with ``in|out.``. You can set 765 the input's property with ``in.prop`` and the output's property with 766 ``out.prop``. For example: 767 768 :: 769 770 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 771 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 772 773 NOTE: parameter validation is known to be incomplete, in many cases 774 specifying an invalid option causes QEMU to print an error message 775 and continue emulation without sound. 776 777 Valid global options are: 778 779 ``id=identifier`` 780 Identifies the audio backend. 781 782 ``timer-period=period`` 783 Sets the timer period used by the audio subsystem in 784 microseconds. Default is 10000 (10 ms). 785 786 ``in|out.mixing-engine=on|off`` 787 Use QEMU's mixing engine to mix all streams inside QEMU and 788 convert audio formats when not supported by the backend. When 789 off, fixed-settings must be off too. Note that disabling this 790 option means that the selected backend must support multiple 791 streams and the audio formats used by the virtual cards, 792 otherwise you'll get no sound. It's not recommended to disable 793 this option unless you want to use 5.1 or 7.1 audio, as mixing 794 engine only supports mono and stereo audio. Default is on. 795 796 ``in|out.fixed-settings=on|off`` 797 Use fixed settings for host audio. When off, it will change 798 based on how the guest opens the sound card. In this case you 799 must not specify frequency, channels or format. Default is on. 800 801 ``in|out.frequency=frequency`` 802 Specify the frequency to use when using fixed-settings. Default 803 is 44100Hz. 804 805 ``in|out.channels=channels`` 806 Specify the number of channels to use when using fixed-settings. 807 Default is 2 (stereo). 808 809 ``in|out.format=format`` 810 Specify the sample format to use when using fixed-settings. 811 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 812 ``u32``, ``f32``. Default is ``s16``. 813 814 ``in|out.voices=voices`` 815 Specify the number of voices to use. Default is 1. 816 817 ``in|out.buffer-length=usecs`` 818 Sets the size of the buffer in microseconds. 819 820``-audiodev none,id=id[,prop[=value][,...]]`` 821 Creates a dummy backend that discards all outputs. This backend has 822 no backend specific properties. 823 824``-audiodev alsa,id=id[,prop[=value][,...]]`` 825 Creates backend using the ALSA. This backend is only available on 826 Linux. 827 828 ALSA specific options are: 829 830 ``in|out.dev=device`` 831 Specify the ALSA device to use for input and/or output. Default 832 is ``default``. 833 834 ``in|out.period-length=usecs`` 835 Sets the period length in microseconds. 836 837 ``in|out.try-poll=on|off`` 838 Attempt to use poll mode with the device. Default is on. 839 840 ``threshold=threshold`` 841 Threshold (in microseconds) when playback starts. Default is 0. 842 843``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 844 Creates a backend using Apple's Core Audio. This backend is only 845 available on Mac OS and only supports playback. 846 847 Core Audio specific options are: 848 849 ``in|out.buffer-count=count`` 850 Sets the count of the buffers. 851 852``-audiodev dsound,id=id[,prop[=value][,...]]`` 853 Creates a backend using Microsoft's DirectSound. This backend is 854 only available on Windows and only supports playback. 855 856 DirectSound specific options are: 857 858 ``latency=usecs`` 859 Add extra usecs microseconds latency to playback. Default is 860 10000 (10 ms). 861 862``-audiodev oss,id=id[,prop[=value][,...]]`` 863 Creates a backend using OSS. This backend is available on most 864 Unix-like systems. 865 866 OSS specific options are: 867 868 ``in|out.dev=device`` 869 Specify the file name of the OSS device to use. Default is 870 ``/dev/dsp``. 871 872 ``in|out.buffer-count=count`` 873 Sets the count of the buffers. 874 875 ``in|out.try-poll=on|of`` 876 Attempt to use poll mode with the device. Default is on. 877 878 ``try-mmap=on|off`` 879 Try using memory mapped device access. Default is off. 880 881 ``exclusive=on|off`` 882 Open the device in exclusive mode (vmix won't work in this 883 case). Default is off. 884 885 ``dsp-policy=policy`` 886 Sets the timing policy (between 0 and 10, where smaller number 887 means smaller latency but higher CPU usage). Use -1 to use 888 buffer sizes specified by ``buffer`` and ``buffer-count``. This 889 option is ignored if you do not have OSS 4. Default is 5. 890 891``-audiodev pa,id=id[,prop[=value][,...]]`` 892 Creates a backend using PulseAudio. This backend is available on 893 most systems. 894 895 PulseAudio specific options are: 896 897 ``server=server`` 898 Sets the PulseAudio server to connect to. 899 900 ``in|out.name=sink`` 901 Use the specified source/sink for recording/playback. 902 903 ``in|out.latency=usecs`` 904 Desired latency in microseconds. The PulseAudio server will try 905 to honor this value but actual latencies may be lower or higher. 906 907``-audiodev sdl,id=id[,prop[=value][,...]]`` 908 Creates a backend using SDL. This backend is available on most 909 systems, but you should use your platform's native backend if 910 possible. 911 912 SDL specific options are: 913 914 ``in|out.buffer-count=count`` 915 Sets the count of the buffers. 916 917``-audiodev spice,id=id[,prop[=value][,...]]`` 918 Creates a backend that sends audio through SPICE. This backend 919 requires ``-spice`` and automatically selected in that case, so 920 usually you can ignore this option. This backend has no backend 921 specific properties. 922 923``-audiodev wav,id=id[,prop[=value][,...]]`` 924 Creates a backend that writes audio to a WAV file. 925 926 Backend specific options are: 927 928 ``path=path`` 929 Write recorded audio into the specified file. Default is 930 ``qemu.wav``. 931ERST 932 933DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 934 "-soundhw c1,... enable audio support\n" 935 " and only specified sound cards (comma separated list)\n" 936 " use '-soundhw help' to get the list of supported cards\n" 937 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 938SRST 939``-soundhw card1[,card2,...] or -soundhw all`` 940 Enable audio and selected sound hardware. Use 'help' to print all 941 available sound hardware. For example: 942 943 .. parsed-literal:: 944 945 |qemu_system_x86| -soundhw sb16,adlib disk.img 946 |qemu_system_x86| -soundhw es1370 disk.img 947 |qemu_system_x86| -soundhw ac97 disk.img 948 |qemu_system_x86| -soundhw hda disk.img 949 |qemu_system_x86| -soundhw all disk.img 950 |qemu_system_x86| -soundhw help 951 952 Note that Linux's i810\_audio OSS kernel (for AC97) module might 953 require manually specifying clocking. 954 955 :: 956 957 modprobe i810_audio clocking=48000 958ERST 959 960DEF("device", HAS_ARG, QEMU_OPTION_device, 961 "-device driver[,prop[=value][,...]]\n" 962 " add device (based on driver)\n" 963 " prop=value,... sets driver properties\n" 964 " use '-device help' to print all possible drivers\n" 965 " use '-device driver,help' to print all possible properties\n", 966 QEMU_ARCH_ALL) 967SRST 968``-device driver[,prop[=value][,...]]`` 969 Add device driver. prop=value sets driver properties. Valid 970 properties depend on the driver. To get help on possible drivers and 971 properties, use ``-device help`` and ``-device driver,help``. 972 973 Some drivers are: 974 975``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 976 Add an IPMI BMC. This is a simulation of a hardware management 977 interface processor that normally sits on a system. It provides a 978 watchdog and the ability to reset and power control the system. You 979 need to connect this to an IPMI interface to make it useful 980 981 The IPMI slave address to use for the BMC. The default is 0x20. This 982 address is the BMC's address on the I2C network of management 983 controllers. If you don't know what this means, it is safe to ignore 984 it. 985 986 ``id=id`` 987 The BMC id for interfaces to use this device. 988 989 ``slave_addr=val`` 990 Define slave address to use for the BMC. The default is 0x20. 991 992 ``sdrfile=file`` 993 file containing raw Sensor Data Records (SDR) data. The default 994 is none. 995 996 ``fruareasize=val`` 997 size of a Field Replaceable Unit (FRU) area. The default is 998 1024. 999 1000 ``frudatafile=file`` 1001 file containing raw Field Replaceable Unit (FRU) inventory data. 1002 The default is none. 1003 1004 ``guid=uuid`` 1005 value for the GUID for the BMC, in standard UUID format. If this 1006 is set, get "Get GUID" command to the BMC will return it. 1007 Otherwise "Get GUID" will return an error. 1008 1009``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1010 Add a connection to an external IPMI BMC simulator. Instead of 1011 locally emulating the BMC like the above item, instead connect to an 1012 external entity that provides the IPMI services. 1013 1014 A connection is made to an external BMC simulator. If you do this, 1015 it is strongly recommended that you use the "reconnect=" chardev 1016 option to reconnect to the simulator if the connection is lost. Note 1017 that if this is not used carefully, it can be a security issue, as 1018 the interface has the ability to send resets, NMIs, and power off 1019 the VM. It's best if QEMU makes a connection to an external 1020 simulator running on a secure port on localhost, so neither the 1021 simulator nor QEMU is exposed to any outside network. 1022 1023 See the "lanserv/README.vm" file in the OpenIPMI library for more 1024 details on the external interface. 1025 1026``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1027 Add a KCS IPMI interafce on the ISA bus. This also adds a 1028 corresponding ACPI and SMBIOS entries, if appropriate. 1029 1030 ``bmc=id`` 1031 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1032 above. 1033 1034 ``ioport=val`` 1035 Define the I/O address of the interface. The default is 0xca0 1036 for KCS. 1037 1038 ``irq=val`` 1039 Define the interrupt to use. The default is 5. To disable 1040 interrupts, set this to 0. 1041 1042``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1043 Like the KCS interface, but defines a BT interface. The default port 1044 is 0xe4 and the default interrupt is 5. 1045 1046``-device pci-ipmi-kcs,bmc=id`` 1047 Add a KCS IPMI interafce on the PCI bus. 1048 1049 ``bmc=id`` 1050 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1051 1052``-device pci-ipmi-bt,bmc=id`` 1053 Like the KCS interface, but defines a BT interface on the PCI bus. 1054 1055``-device intel-iommu[,option=...]`` 1056 This is only supported by ``-machine q35``, which will enable Intel VT-d 1057 emulation within the guest. It supports below options: 1058 1059 ``intremap=on|off`` (default: auto) 1060 This enables interrupt remapping feature. It's required to enable 1061 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1062 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1063 The default value is "auto", which will be decided by the mode of 1064 kernel-irqchip. 1065 1066 ``caching-mode=on|off`` (default: off) 1067 This enables caching mode for the VT-d emulated device. When 1068 caching-mode is enabled, each guest DMA buffer mapping will generate an 1069 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1070 a synchronous way. It is required for ``-device vfio-pci`` to work 1071 with the VT-d device, because host assigned devices requires to setup 1072 the DMA mapping on the host before guest DMA starts. 1073 1074 ``device-iotlb=on|off`` (default: off) 1075 This enables device-iotlb capability for the emulated VT-d device. So 1076 far virtio/vhost should be the only real user for this parameter, 1077 paired with ats=on configured for the device. 1078 1079 ``aw-bits=39|48`` (default: 39) 1080 This decides the address width of IOVA address space. The address 1081 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1082 4-level IOMMU page tables. 1083 1084 Please also refer to the wiki page for general scenarios of VT-d 1085 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1086 1087ERST 1088 1089DEF("name", HAS_ARG, QEMU_OPTION_name, 1090 "-name string1[,process=string2][,debug-threads=on|off]\n" 1091 " set the name of the guest\n" 1092 " string1 sets the window title and string2 the process name\n" 1093 " When debug-threads is enabled, individual threads are given a separate name\n" 1094 " NOTE: The thread names are for debugging and not a stable API.\n", 1095 QEMU_ARCH_ALL) 1096SRST 1097``-name name`` 1098 Sets the name of the guest. This name will be displayed in the SDL 1099 window caption. The name will also be used for the VNC server. Also 1100 optionally set the top visible process name in Linux. Naming of 1101 individual threads can also be enabled on Linux to aid debugging. 1102ERST 1103 1104DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1105 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1106 " specify machine UUID\n", QEMU_ARCH_ALL) 1107SRST 1108``-uuid uuid`` 1109 Set system UUID. 1110ERST 1111 1112DEFHEADING() 1113 1114DEFHEADING(Block device options:) 1115 1116DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1117 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1118DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1119SRST 1120``-fda file`` 1121 \ 1122``-fdb file`` 1123 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1124 the System Emulation Users Guide). 1125ERST 1126 1127DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1128 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1129DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1130DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1131 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1132DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1133SRST 1134``-hda file`` 1135 \ 1136``-hdb file`` 1137 \ 1138``-hdc file`` 1139 \ 1140``-hdd file`` 1141 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1142 chapter in the System Emulation Users Guide). 1143ERST 1144 1145DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1146 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1147 QEMU_ARCH_ALL) 1148SRST 1149``-cdrom file`` 1150 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1151 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1152 as filename. 1153ERST 1154 1155DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1156 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1157 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1158 " [,read-only=on|off][,auto-read-only=on|off]\n" 1159 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1160 " [,driver specific parameters...]\n" 1161 " configure a block backend\n", QEMU_ARCH_ALL) 1162SRST 1163``-blockdev option[,option[,option[,...]]]`` 1164 Define a new block driver node. Some of the options apply to all 1165 block drivers, other options are only accepted for a specific block 1166 driver. See below for a list of generic options and options for the 1167 most common block drivers. 1168 1169 Options that expect a reference to another node (e.g. ``file``) can 1170 be given in two ways. Either you specify the node name of an already 1171 existing node (file=node-name), or you define a new node inline, 1172 adding options for the referenced node after a dot 1173 (file.filename=path,file.aio=native). 1174 1175 A block driver node created with ``-blockdev`` can be used for a 1176 guest device by specifying its node name for the ``drive`` property 1177 in a ``-device`` argument that defines a block device. 1178 1179 ``Valid options for any block driver node:`` 1180 ``driver`` 1181 Specifies the block driver to use for the given node. 1182 1183 ``node-name`` 1184 This defines the name of the block driver node by which it 1185 will be referenced later. The name must be unique, i.e. it 1186 must not match the name of a different block driver node, or 1187 (if you use ``-drive`` as well) the ID of a drive. 1188 1189 If no node name is specified, it is automatically generated. 1190 The generated node name is not intended to be predictable 1191 and changes between QEMU invocations. For the top level, an 1192 explicit node name must be specified. 1193 1194 ``read-only`` 1195 Open the node read-only. Guest write attempts will fail. 1196 1197 Note that some block drivers support only read-only access, 1198 either generally or in certain configurations. In this case, 1199 the default value ``read-only=off`` does not work and the 1200 option must be specified explicitly. 1201 1202 ``auto-read-only`` 1203 If ``auto-read-only=on`` is set, QEMU may fall back to 1204 read-only usage even when ``read-only=off`` is requested, or 1205 even switch between modes as needed, e.g. depending on 1206 whether the image file is writable or whether a writing user 1207 is attached to the node. 1208 1209 ``force-share`` 1210 Override the image locking system of QEMU by forcing the 1211 node to utilize weaker shared access for permissions where 1212 it would normally request exclusive access. When there is 1213 the potential for multiple instances to have the same file 1214 open (whether this invocation of QEMU is the first or the 1215 second instance), both instances must permit shared access 1216 for the second instance to succeed at opening the file. 1217 1218 Enabling ``force-share=on`` requires ``read-only=on``. 1219 1220 ``cache.direct`` 1221 The host page cache can be avoided with ``cache.direct=on``. 1222 This will attempt to do disk IO directly to the guest's 1223 memory. QEMU may still perform an internal copy of the data. 1224 1225 ``cache.no-flush`` 1226 In case you don't care about data integrity over host 1227 failures, you can use ``cache.no-flush=on``. This option 1228 tells QEMU that it never needs to write any data to the disk 1229 but can instead keep things in cache. If anything goes 1230 wrong, like your host losing power, the disk storage getting 1231 disconnected accidentally, etc. your image will most 1232 probably be rendered unusable. 1233 1234 ``discard=discard`` 1235 discard is one of "ignore" (or "off") or "unmap" (or "on") 1236 and controls whether ``discard`` (also known as ``trim`` or 1237 ``unmap``) requests are ignored or passed to the filesystem. 1238 Some machine types may not support discard requests. 1239 1240 ``detect-zeroes=detect-zeroes`` 1241 detect-zeroes is "off", "on" or "unmap" and enables the 1242 automatic conversion of plain zero writes by the OS to 1243 driver specific optimized zero write commands. You may even 1244 choose "unmap" if discard is set to "unmap" to allow a zero 1245 write to be converted to an ``unmap`` operation. 1246 1247 ``Driver-specific options for file`` 1248 This is the protocol-level block driver for accessing regular 1249 files. 1250 1251 ``filename`` 1252 The path to the image file in the local filesystem 1253 1254 ``aio`` 1255 Specifies the AIO backend (threads/native/io_uring, 1256 default: threads) 1257 1258 ``locking`` 1259 Specifies whether the image file is protected with Linux OFD 1260 / POSIX locks. The default is to use the Linux Open File 1261 Descriptor API if available, otherwise no lock is applied. 1262 (auto/on/off, default: auto) 1263 1264 Example: 1265 1266 :: 1267 1268 -blockdev driver=file,node-name=disk,filename=disk.img 1269 1270 ``Driver-specific options for raw`` 1271 This is the image format block driver for raw images. It is 1272 usually stacked on top of a protocol level block driver such as 1273 ``file``. 1274 1275 ``file`` 1276 Reference to or definition of the data source block driver 1277 node (e.g. a ``file`` driver node) 1278 1279 Example 1: 1280 1281 :: 1282 1283 -blockdev driver=file,node-name=disk_file,filename=disk.img 1284 -blockdev driver=raw,node-name=disk,file=disk_file 1285 1286 Example 2: 1287 1288 :: 1289 1290 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1291 1292 ``Driver-specific options for qcow2`` 1293 This is the image format block driver for qcow2 images. It is 1294 usually stacked on top of a protocol level block driver such as 1295 ``file``. 1296 1297 ``file`` 1298 Reference to or definition of the data source block driver 1299 node (e.g. a ``file`` driver node) 1300 1301 ``backing`` 1302 Reference to or definition of the backing file block device 1303 (default is taken from the image file). It is allowed to 1304 pass ``null`` here in order to disable the default backing 1305 file. 1306 1307 ``lazy-refcounts`` 1308 Whether to enable the lazy refcounts feature (on/off; 1309 default is taken from the image file) 1310 1311 ``cache-size`` 1312 The maximum total size of the L2 table and refcount block 1313 caches in bytes (default: the sum of l2-cache-size and 1314 refcount-cache-size) 1315 1316 ``l2-cache-size`` 1317 The maximum size of the L2 table cache in bytes (default: if 1318 cache-size is not specified - 32M on Linux platforms, and 8M 1319 on non-Linux platforms; otherwise, as large as possible 1320 within the cache-size, while permitting the requested or the 1321 minimal refcount cache size) 1322 1323 ``refcount-cache-size`` 1324 The maximum size of the refcount block cache in bytes 1325 (default: 4 times the cluster size; or if cache-size is 1326 specified, the part of it which is not used for the L2 1327 cache) 1328 1329 ``cache-clean-interval`` 1330 Clean unused entries in the L2 and refcount caches. The 1331 interval is in seconds. The default value is 600 on 1332 supporting platforms, and 0 on other platforms. Setting it 1333 to 0 disables this feature. 1334 1335 ``pass-discard-request`` 1336 Whether discard requests to the qcow2 device should be 1337 forwarded to the data source (on/off; default: on if 1338 discard=unmap is specified, off otherwise) 1339 1340 ``pass-discard-snapshot`` 1341 Whether discard requests for the data source should be 1342 issued when a snapshot operation (e.g. deleting a snapshot) 1343 frees clusters in the qcow2 file (on/off; default: on) 1344 1345 ``pass-discard-other`` 1346 Whether discard requests for the data source should be 1347 issued on other occasions where a cluster gets freed 1348 (on/off; default: off) 1349 1350 ``overlap-check`` 1351 Which overlap checks to perform for writes to the image 1352 (none/constant/cached/all; default: cached). For details or 1353 finer granularity control refer to the QAPI documentation of 1354 ``blockdev-add``. 1355 1356 Example 1: 1357 1358 :: 1359 1360 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1361 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1362 1363 Example 2: 1364 1365 :: 1366 1367 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1368 1369 ``Driver-specific options for other drivers`` 1370 Please refer to the QAPI documentation of the ``blockdev-add`` 1371 QMP command. 1372ERST 1373 1374DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1375 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1376 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1377 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1378 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1379 " [,aio=threads|native|io_uring]\n" 1380 " [,readonly=on|off][,copy-on-read=on|off]\n" 1381 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1382 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1383 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1384 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1385 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1386 " [[,iops_size=is]]\n" 1387 " [[,group=g]]\n" 1388 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1389SRST 1390``-drive option[,option[,option[,...]]]`` 1391 Define a new drive. This includes creating a block driver node (the 1392 backend) as well as a guest device, and is mostly a shortcut for 1393 defining the corresponding ``-blockdev`` and ``-device`` options. 1394 1395 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1396 In addition, it knows the following options: 1397 1398 ``file=file`` 1399 This option defines which disk image (see the :ref:`disk images` 1400 chapter in the System Emulation Users Guide) to use with this drive. 1401 If the filename contains comma, you must double it (for instance, 1402 "file=my,,file" to use file "my,file"). 1403 1404 Special files such as iSCSI devices can be specified using 1405 protocol specific URLs. See the section for "Device URL Syntax" 1406 for more information. 1407 1408 ``if=interface`` 1409 This option defines on which type on interface the drive is 1410 connected. Available types are: ide, scsi, sd, mtd, floppy, 1411 pflash, virtio, none. 1412 1413 ``bus=bus,unit=unit`` 1414 These options define where is connected the drive by defining 1415 the bus number and the unit id. 1416 1417 ``index=index`` 1418 This option defines where the drive is connected by using an 1419 index in the list of available connectors of a given interface 1420 type. 1421 1422 ``media=media`` 1423 This option defines the type of the media: disk or cdrom. 1424 1425 ``snapshot=snapshot`` 1426 snapshot is "on" or "off" and controls snapshot mode for the 1427 given drive (see ``-snapshot``). 1428 1429 ``cache=cache`` 1430 cache is "none", "writeback", "unsafe", "directsync" or 1431 "writethrough" and controls how the host cache is used to access 1432 block data. This is a shortcut that sets the ``cache.direct`` 1433 and ``cache.no-flush`` options (as in ``-blockdev``), and 1434 additionally ``cache.writeback``, which provides a default for 1435 the ``write-cache`` option of block guest devices (as in 1436 ``-device``). The modes correspond to the following settings: 1437 1438 ============= =============== ============ ============== 1439 \ cache.writeback cache.direct cache.no-flush 1440 ============= =============== ============ ============== 1441 writeback on off off 1442 none on on off 1443 writethrough off off off 1444 directsync off on off 1445 unsafe on off on 1446 ============= =============== ============ ============== 1447 1448 The default mode is ``cache=writeback``. 1449 1450 ``aio=aio`` 1451 aio is "threads", "native", or "io_uring" and selects between pthread 1452 based disk I/O, native Linux AIO, or Linux io_uring API. 1453 1454 ``format=format`` 1455 Specify which disk format will be used rather than detecting the 1456 format. Can be used to specify format=raw to avoid interpreting 1457 an untrusted format header. 1458 1459 ``werror=action,rerror=action`` 1460 Specify which action to take on write and read errors. Valid 1461 actions are: "ignore" (ignore the error and try to continue), 1462 "stop" (pause QEMU), "report" (report the error to the guest), 1463 "enospc" (pause QEMU only if the host disk is full; report the 1464 error to the guest otherwise). The default setting is 1465 ``werror=enospc`` and ``rerror=report``. 1466 1467 ``copy-on-read=copy-on-read`` 1468 copy-on-read is "on" or "off" and enables whether to copy read 1469 backing file sectors into the image file. 1470 1471 ``bps=b,bps_rd=r,bps_wr=w`` 1472 Specify bandwidth throttling limits in bytes per second, either 1473 for all request types or for reads or writes only. Small values 1474 can lead to timeouts or hangs inside the guest. A safe minimum 1475 for disks is 2 MB/s. 1476 1477 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1478 Specify bursts in bytes per second, either for all request types 1479 or for reads or writes only. Bursts allow the guest I/O to spike 1480 above the limit temporarily. 1481 1482 ``iops=i,iops_rd=r,iops_wr=w`` 1483 Specify request rate limits in requests per second, either for 1484 all request types or for reads or writes only. 1485 1486 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1487 Specify bursts in requests per second, either for all request 1488 types or for reads or writes only. Bursts allow the guest I/O to 1489 spike above the limit temporarily. 1490 1491 ``iops_size=is`` 1492 Let every is bytes of a request count as a new request for iops 1493 throttling purposes. Use this option to prevent guests from 1494 circumventing iops limits by sending fewer but larger requests. 1495 1496 ``group=g`` 1497 Join a throttling quota group with given name g. All drives that 1498 are members of the same group are accounted for together. Use 1499 this option to prevent guests from circumventing throttling 1500 limits by using many small disks instead of a single larger 1501 disk. 1502 1503 By default, the ``cache.writeback=on`` mode is used. It will report 1504 data writes as completed as soon as the data is present in the host 1505 page cache. This is safe as long as your guest OS makes sure to 1506 correctly flush disk caches where needed. If your guest OS does not 1507 handle volatile disk write caches correctly and your host crashes or 1508 loses power, then the guest may experience data corruption. 1509 1510 For such guests, you should consider using ``cache.writeback=off``. 1511 This means that the host page cache will be used to read and write 1512 data, but write notification will be sent to the guest only after 1513 QEMU has made sure to flush each write to the disk. Be aware that 1514 this has a major impact on performance. 1515 1516 When using the ``-snapshot`` option, unsafe caching is always used. 1517 1518 Copy-on-read avoids accessing the same backing file sectors 1519 repeatedly and is useful when the backing file is over a slow 1520 network. By default copy-on-read is off. 1521 1522 Instead of ``-cdrom`` you can use: 1523 1524 .. parsed-literal:: 1525 1526 |qemu_system| -drive file=file,index=2,media=cdrom 1527 1528 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1529 1530 .. parsed-literal:: 1531 1532 |qemu_system| -drive file=file,index=0,media=disk 1533 |qemu_system| -drive file=file,index=1,media=disk 1534 |qemu_system| -drive file=file,index=2,media=disk 1535 |qemu_system| -drive file=file,index=3,media=disk 1536 1537 You can open an image using pre-opened file descriptors from an fd 1538 set: 1539 1540 .. parsed-literal:: 1541 1542 |qemu_system| \\ 1543 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1544 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1545 -drive file=/dev/fdset/2,index=0,media=disk 1546 1547 You can connect a CDROM to the slave of ide0: 1548 1549 .. parsed-literal:: 1550 1551 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1552 1553 If you don't specify the "file=" argument, you define an empty 1554 drive: 1555 1556 .. parsed-literal:: 1557 1558 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1559 1560 Instead of ``-fda``, ``-fdb``, you can use: 1561 1562 .. parsed-literal:: 1563 1564 |qemu_system_x86| -drive file=file,index=0,if=floppy 1565 |qemu_system_x86| -drive file=file,index=1,if=floppy 1566 1567 By default, interface is "ide" and index is automatically 1568 incremented: 1569 1570 .. parsed-literal:: 1571 1572 |qemu_system_x86| -drive file=a -drive file=b" 1573 1574 is interpreted like: 1575 1576 .. parsed-literal:: 1577 1578 |qemu_system_x86| -hda a -hdb b 1579ERST 1580 1581DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1582 "-mtdblock file use 'file' as on-board Flash memory image\n", 1583 QEMU_ARCH_ALL) 1584SRST 1585``-mtdblock file`` 1586 Use file as on-board Flash memory image. 1587ERST 1588 1589DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1590 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1591SRST 1592``-sd file`` 1593 Use file as SecureDigital card image. 1594ERST 1595 1596DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1597 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1598SRST 1599``-pflash file`` 1600 Use file as a parallel flash image. 1601ERST 1602 1603DEF("snapshot", 0, QEMU_OPTION_snapshot, 1604 "-snapshot write to temporary files instead of disk image files\n", 1605 QEMU_ARCH_ALL) 1606SRST 1607``-snapshot`` 1608 Write to temporary files instead of disk image files. In this case, 1609 the raw disk image you use is not written back. You can however 1610 force the write back by pressing C-a s (see the :ref:`disk images` 1611 chapter in the System Emulation Users Guide). 1612ERST 1613 1614DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1615 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1616 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1617 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1618 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1619 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1620 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1621 " [[,throttling.iops-size=is]]\n" 1622 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1623 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1624 "-fsdev synth,id=id\n", 1625 QEMU_ARCH_ALL) 1626 1627SRST 1628``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1629 \ 1630``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1631 \ 1632``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1633 \ 1634``-fsdev synth,id=id[,readonly=on]`` 1635 Define a new file system device. Valid options are: 1636 1637 ``local`` 1638 Accesses to the filesystem are done by QEMU. 1639 1640 ``proxy`` 1641 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1642 1643 ``synth`` 1644 Synthetic filesystem, only used by QTests. 1645 1646 ``id=id`` 1647 Specifies identifier for this device. 1648 1649 ``path=path`` 1650 Specifies the export path for the file system device. Files 1651 under this path will be available to the 9p client on the guest. 1652 1653 ``security_model=security_model`` 1654 Specifies the security model to be used for this export path. 1655 Supported security models are "passthrough", "mapped-xattr", 1656 "mapped-file" and "none". In "passthrough" security model, files 1657 are stored using the same credentials as they are created on the 1658 guest. This requires QEMU to run as root. In "mapped-xattr" 1659 security model, some of the file attributes like uid, gid, mode 1660 bits and link target are stored as file attributes. For 1661 "mapped-file" these attributes are stored in the hidden 1662 .virtfs\_metadata directory. Directories exported by this 1663 security model cannot interact with other unix tools. "none" 1664 security model is same as passthrough except the sever won't 1665 report failures if it fails to set file attributes like 1666 ownership. Security model is mandatory only for local fsdriver. 1667 Other fsdrivers (like proxy) don't take security model as a 1668 parameter. 1669 1670 ``writeout=writeout`` 1671 This is an optional argument. The only supported value is 1672 "immediate". This means that host page cache will be used to 1673 read and write data but write notification will be sent to the 1674 guest only when the data has been reported as written by the 1675 storage subsystem. 1676 1677 ``readonly=on`` 1678 Enables exporting 9p share as a readonly mount for guests. By 1679 default read-write access is given. 1680 1681 ``socket=socket`` 1682 Enables proxy filesystem driver to use passed socket file for 1683 communicating with virtfs-proxy-helper(1). 1684 1685 ``sock_fd=sock_fd`` 1686 Enables proxy filesystem driver to use passed socket descriptor 1687 for communicating with virtfs-proxy-helper(1). Usually a helper 1688 like libvirt will create socketpair and pass one of the fds as 1689 sock\_fd. 1690 1691 ``fmode=fmode`` 1692 Specifies the default mode for newly created files on the host. 1693 Works only with security models "mapped-xattr" and 1694 "mapped-file". 1695 1696 ``dmode=dmode`` 1697 Specifies the default mode for newly created directories on the 1698 host. Works only with security models "mapped-xattr" and 1699 "mapped-file". 1700 1701 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1702 Specify bandwidth throttling limits in bytes per second, either 1703 for all request types or for reads or writes only. 1704 1705 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1706 Specify bursts in bytes per second, either for all request types 1707 or for reads or writes only. Bursts allow the guest I/O to spike 1708 above the limit temporarily. 1709 1710 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1711 Specify request rate limits in requests per second, either for 1712 all request types or for reads or writes only. 1713 1714 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1715 Specify bursts in requests per second, either for all request 1716 types or for reads or writes only. Bursts allow the guest I/O to 1717 spike above the limit temporarily. 1718 1719 ``throttling.iops-size=is`` 1720 Let every is bytes of a request count as a new request for iops 1721 throttling purposes. 1722 1723 -fsdev option is used along with -device driver "virtio-9p-...". 1724 1725``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1726 Options for virtio-9p-... driver are: 1727 1728 ``type`` 1729 Specifies the variant to be used. Supported values are "pci", 1730 "ccw" or "device", depending on the machine type. 1731 1732 ``fsdev=id`` 1733 Specifies the id value specified along with -fsdev option. 1734 1735 ``mount_tag=mount_tag`` 1736 Specifies the tag name to be used by the guest to mount this 1737 export point. 1738ERST 1739 1740DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1741 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1742 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1743 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1744 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1745 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1746 QEMU_ARCH_ALL) 1747 1748SRST 1749``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1750 \ 1751``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1752 \ 1753``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1754 \ 1755``-virtfs synth,mount_tag=mount_tag`` 1756 Define a new virtual filesystem device and expose it to the guest using 1757 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1758 directory on host is made directly accessible by guest as a pass-through 1759 file system by using the 9P network protocol for communication between 1760 host and guests, if desired even accessible, shared by several guests 1761 simultaniously. 1762 1763 Note that ``-virtfs`` is actually just a convenience shortcut for its 1764 generalized form ``-fsdev -device virtio-9p-pci``. 1765 1766 The general form of pass-through file system options are: 1767 1768 ``local`` 1769 Accesses to the filesystem are done by QEMU. 1770 1771 ``proxy`` 1772 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1773 1774 ``synth`` 1775 Synthetic filesystem, only used by QTests. 1776 1777 ``id=id`` 1778 Specifies identifier for the filesystem device 1779 1780 ``path=path`` 1781 Specifies the export path for the file system device. Files 1782 under this path will be available to the 9p client on the guest. 1783 1784 ``security_model=security_model`` 1785 Specifies the security model to be used for this export path. 1786 Supported security models are "passthrough", "mapped-xattr", 1787 "mapped-file" and "none". In "passthrough" security model, files 1788 are stored using the same credentials as they are created on the 1789 guest. This requires QEMU to run as root. In "mapped-xattr" 1790 security model, some of the file attributes like uid, gid, mode 1791 bits and link target are stored as file attributes. For 1792 "mapped-file" these attributes are stored in the hidden 1793 .virtfs\_metadata directory. Directories exported by this 1794 security model cannot interact with other unix tools. "none" 1795 security model is same as passthrough except the sever won't 1796 report failures if it fails to set file attributes like 1797 ownership. Security model is mandatory only for local fsdriver. 1798 Other fsdrivers (like proxy) don't take security model as a 1799 parameter. 1800 1801 ``writeout=writeout`` 1802 This is an optional argument. The only supported value is 1803 "immediate". This means that host page cache will be used to 1804 read and write data but write notification will be sent to the 1805 guest only when the data has been reported as written by the 1806 storage subsystem. 1807 1808 ``readonly=on`` 1809 Enables exporting 9p share as a readonly mount for guests. By 1810 default read-write access is given. 1811 1812 ``socket=socket`` 1813 Enables proxy filesystem driver to use passed socket file for 1814 communicating with virtfs-proxy-helper(1). Usually a helper like 1815 libvirt will create socketpair and pass one of the fds as 1816 sock\_fd. 1817 1818 ``sock_fd`` 1819 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1820 socket descriptor for interfacing with virtfs-proxy-helper(1). 1821 1822 ``fmode=fmode`` 1823 Specifies the default mode for newly created files on the host. 1824 Works only with security models "mapped-xattr" and 1825 "mapped-file". 1826 1827 ``dmode=dmode`` 1828 Specifies the default mode for newly created directories on the 1829 host. Works only with security models "mapped-xattr" and 1830 "mapped-file". 1831 1832 ``mount_tag=mount_tag`` 1833 Specifies the tag name to be used by the guest to mount this 1834 export point. 1835 1836 ``multidevs=multidevs`` 1837 Specifies how to deal with multiple devices being shared with a 1838 9p export. Supported behaviours are either "remap", "forbid" or 1839 "warn". The latter is the default behaviour on which virtfs 9p 1840 expects only one device to be shared with the same export, and 1841 if more than one device is shared and accessed via the same 9p 1842 export then only a warning message is logged (once) by qemu on 1843 host side. In order to avoid file ID collisions on guest you 1844 should either create a separate virtfs export for each device to 1845 be shared with guests (recommended way) or you might use "remap" 1846 instead which allows you to share multiple devices with only one 1847 export instead, which is achieved by remapping the original 1848 inode numbers from host to guest in a way that would prevent 1849 such collisions. Remapping inodes in such use cases is required 1850 because the original device IDs from host are never passed and 1851 exposed on guest. Instead all files of an export shared with 1852 virtfs always share the same device id on guest. So two files 1853 with identical inode numbers but from actually different devices 1854 on host would otherwise cause a file ID collision and hence 1855 potential misbehaviours on guest. "forbid" on the other hand 1856 assumes like "warn" that only one device is shared by the same 1857 export, however it will not only log a warning message but also 1858 deny access to additional devices on guest. Note though that 1859 "forbid" does currently not block all possible file access 1860 operations (e.g. readdir() would still return entries from other 1861 devices). 1862ERST 1863 1864DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1865 "-iscsi [user=user][,password=password]\n" 1866 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1867 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1868 " [,timeout=timeout]\n" 1869 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1870 1871SRST 1872``-iscsi`` 1873 Configure iSCSI session parameters. 1874ERST 1875 1876DEFHEADING() 1877 1878DEFHEADING(USB convenience options:) 1879 1880DEF("usb", 0, QEMU_OPTION_usb, 1881 "-usb enable on-board USB host controller (if not enabled by default)\n", 1882 QEMU_ARCH_ALL) 1883SRST 1884``-usb`` 1885 Enable USB emulation on machine types with an on-board USB host 1886 controller (if not enabled by default). Note that on-board USB host 1887 controllers may not support USB 3.0. In this case 1888 ``-device qemu-xhci`` can be used instead on machines with PCI. 1889ERST 1890 1891DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1892 "-usbdevice name add the host or guest USB device 'name'\n", 1893 QEMU_ARCH_ALL) 1894SRST 1895``-usbdevice devname`` 1896 Add the USB device devname, and enable an on-board USB controller 1897 if possible and necessary (just like it can be done via 1898 ``-machine usb=on``). Note that this option is mainly intended for 1899 the user's convenience only. More fine-grained control can be 1900 achieved by selecting a USB host controller (if necessary) and the 1901 desired USB device via the ``-device`` option instead. For example, 1902 instead of using ``-usbdevice mouse`` it is possible to use 1903 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1904 to a USB 3.0 controller instead (at least on machines that support 1905 PCI and do not have an USB controller enabled by default yet). 1906 For more details, see the chapter about 1907 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1908 Possible devices for devname are: 1909 1910 ``braille`` 1911 Braille device. This will use BrlAPI to display the braille 1912 output on a real or fake device (i.e. it also creates a 1913 corresponding ``braille`` chardev automatically beside the 1914 ``usb-braille`` USB device). 1915 1916 ``keyboard`` 1917 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1918 1919 ``mouse`` 1920 Virtual Mouse. This will override the PS/2 mouse emulation when 1921 activated. 1922 1923 ``tablet`` 1924 Pointer device that uses absolute coordinates (like a 1925 touchscreen). This means QEMU is able to report the mouse 1926 position without having to grab the mouse. Also overrides the 1927 PS/2 mouse emulation when activated. 1928 1929 ``wacom-tablet`` 1930 Wacom PenPartner USB tablet. 1931 1932 1933ERST 1934 1935DEFHEADING() 1936 1937DEFHEADING(Display options:) 1938 1939DEF("display", HAS_ARG, QEMU_OPTION_display, 1940#if defined(CONFIG_SPICE) 1941 "-display spice-app[,gl=on|off]\n" 1942#endif 1943#if defined(CONFIG_SDL) 1944 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1945 " [,grab-mod=<mod>][,show-cursor=on|off][,window-close=on|off]\n" 1946#endif 1947#if defined(CONFIG_GTK) 1948 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1949 " [,show-cursor=on|off][,window-close=on|off]\n" 1950#endif 1951#if defined(CONFIG_VNC) 1952 "-display vnc=<display>[,<optargs>]\n" 1953#endif 1954#if defined(CONFIG_CURSES) 1955 "-display curses[,charset=<encoding>]\n" 1956#endif 1957#if defined(CONFIG_COCOA) 1958 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 1959#endif 1960#if defined(CONFIG_OPENGL) 1961 "-display egl-headless[,rendernode=<file>]\n" 1962#endif 1963#if defined(CONFIG_DBUS_DISPLAY) 1964 "-display dbus[,addr=<dbusaddr>]\n" 1965 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1966#endif 1967#if defined(CONFIG_COCOA) 1968 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 1969#endif 1970 "-display none\n" 1971 " select display backend type\n" 1972 " The default display is equivalent to\n " 1973#if defined(CONFIG_GTK) 1974 "\"-display gtk\"\n" 1975#elif defined(CONFIG_SDL) 1976 "\"-display sdl\"\n" 1977#elif defined(CONFIG_COCOA) 1978 "\"-display cocoa\"\n" 1979#elif defined(CONFIG_VNC) 1980 "\"-vnc localhost:0,to=99,id=default\"\n" 1981#else 1982 "\"-display none\"\n" 1983#endif 1984 , QEMU_ARCH_ALL) 1985SRST 1986``-display type`` 1987 Select type of display to use. This option is a replacement for the 1988 old style -sdl/-curses/... options. Use ``-display help`` to list 1989 the available display types. Valid values for type are 1990 1991 ``spice-app[,gl=on|off]`` 1992 Start QEMU as a Spice server and launch the default Spice client 1993 application. The Spice server will redirect the serial consoles 1994 and QEMU monitors. (Since 4.0) 1995 1996 ``dbus`` 1997 Export the display over D-Bus interfaces. (Since 7.0) 1998 1999 The connection is registered with the "org.qemu" name (and queued when 2000 already owned). 2001 2002 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2003 2004 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2005 2006 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2007 will share framebuffers with DMABUF file descriptors). 2008 2009 ``sdl`` 2010 Display video output via SDL (usually in a separate graphics 2011 window; see the SDL documentation for other possibilities). 2012 Valid parameters are: 2013 2014 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2015 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2016 either ``lshift-lctrl-lalt`` or ``rctrl``. 2017 2018 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing. 2019 This parameter is deprecated - use ``grab-mod`` instead. 2020 2021 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing. 2022 This parameter is deprecated - use ``grab-mod`` instead. 2023 2024 ``gl=on|off|core|es`` : Use OpenGL for displaying 2025 2026 ``show-cursor=on|off`` : Force showing the mouse cursor 2027 2028 ``window-close=on|off`` : Allow to quit qemu with window close button 2029 2030 ``gtk`` 2031 Display video output in a GTK window. This interface provides 2032 drop-down menus and other UI elements to configure and control 2033 the VM during runtime. Valid parameters are: 2034 2035 ``full-screen=on|off`` : Start in fullscreen mode 2036 2037 ``gl=on|off`` : Use OpenGL for displaying 2038 2039 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2040 2041 ``show-cursor=on|off`` : Force showing the mouse cursor 2042 2043 ``window-close=on|off`` : Allow to quit qemu with window close button 2044 2045 ``curses[,charset=<encoding>]`` 2046 Display video output via curses. For graphics device models 2047 which support a text mode, QEMU can display this output using a 2048 curses/ncurses interface. Nothing is displayed when the graphics 2049 device is in graphical mode or if the graphics device does not 2050 support a text mode. Generally only the VGA device models 2051 support text mode. The font charset used by the guest can be 2052 specified with the ``charset`` option, for example 2053 ``charset=CP850`` for IBM CP850 encoding. The default is 2054 ``CP437``. 2055 2056 ``cocoa`` 2057 Display video output in a Cocoa window. Mac only. This interface 2058 provides drop-down menus and other UI elements to configure and 2059 control the VM during runtime. Valid parameters are: 2060 2061 ``show-cursor=on|off`` : Force showing the mouse cursor 2062 2063 ``left-command-key=on|off`` : Disable forwarding left command key to host 2064 2065 ``egl-headless[,rendernode=<file>]`` 2066 Offload all OpenGL operations to a local DRI device. For any 2067 graphical display, this display needs to be paired with either 2068 VNC or SPICE displays. 2069 2070 ``vnc=<display>`` 2071 Start a VNC server on display <display> 2072 2073 ``none`` 2074 Do not display video output. The guest will still see an 2075 emulated graphics card, but its output will not be displayed to 2076 the QEMU user. This option differs from the -nographic option in 2077 that it only affects what is done with video output; -nographic 2078 also changes the destination of the serial and parallel port 2079 data. 2080ERST 2081 2082DEF("nographic", 0, QEMU_OPTION_nographic, 2083 "-nographic disable graphical output and redirect serial I/Os to console\n", 2084 QEMU_ARCH_ALL) 2085SRST 2086``-nographic`` 2087 Normally, if QEMU is compiled with graphical window support, it 2088 displays output such as guest graphics, guest console, and the QEMU 2089 monitor in a window. With this option, you can totally disable 2090 graphical output so that QEMU is a simple command line application. 2091 The emulated serial port is redirected on the console and muxed with 2092 the monitor (unless redirected elsewhere explicitly). Therefore, you 2093 can still use QEMU to debug a Linux kernel with a serial console. 2094 Use C-a h for help on switching between the console and monitor. 2095ERST 2096 2097DEF("curses", 0, QEMU_OPTION_curses, 2098 "-curses shorthand for -display curses\n", 2099 QEMU_ARCH_ALL) 2100SRST 2101``-curses`` 2102 Normally, if QEMU is compiled with graphical window support, it 2103 displays output such as guest graphics, guest console, and the QEMU 2104 monitor in a window. With this option, QEMU can display the VGA 2105 output when in text mode using a curses/ncurses interface. Nothing 2106 is displayed in graphical mode. 2107ERST 2108 2109DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 2110 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 2111 QEMU_ARCH_ALL) 2112SRST 2113``-alt-grab`` 2114 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 2115 this also affects the special keys (for fullscreen, monitor-mode 2116 switching, etc). This option is deprecated - please use 2117 ``-display sdl,grab-mod=lshift-lctrl-lalt`` instead. 2118ERST 2119 2120DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 2121 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 2122 QEMU_ARCH_ALL) 2123SRST 2124``-ctrl-grab`` 2125 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 2126 also affects the special keys (for fullscreen, monitor-mode 2127 switching, etc). This option is deprecated - please use 2128 ``-display sdl,grab-mod=rctrl`` instead. 2129ERST 2130 2131DEF("sdl", 0, QEMU_OPTION_sdl, 2132 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 2133SRST 2134``-sdl`` 2135 Enable SDL. 2136ERST 2137 2138#ifdef CONFIG_SPICE 2139DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2140 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2141 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2142 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2143 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2144 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2145 " [,tls-ciphers=<list>]\n" 2146 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2147 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2148 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2149 " [,password=<string>][,password-secret=<secret-id>]\n" 2150 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2151 " [,jpeg-wan-compression=[auto|never|always]]\n" 2152 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2153 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2154 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2155 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2156 " [,gl=[on|off]][,rendernode=<file>]\n" 2157 " enable spice\n" 2158 " at least one of {port, tls-port} is mandatory\n", 2159 QEMU_ARCH_ALL) 2160#endif 2161SRST 2162``-spice option[,option[,...]]`` 2163 Enable the spice remote desktop protocol. Valid options are 2164 2165 ``port=<nr>`` 2166 Set the TCP port spice is listening on for plaintext channels. 2167 2168 ``addr=<addr>`` 2169 Set the IP address spice is listening on. Default is any 2170 address. 2171 2172 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2173 Force using the specified IP version. 2174 2175 ``password=<string>`` 2176 Set the password you need to authenticate. 2177 2178 This option is deprecated and insecure because it leaves the 2179 password visible in the process listing. Use ``password-secret`` 2180 instead. 2181 2182 ``password-secret=<secret-id>`` 2183 Set the ID of the ``secret`` object containing the password 2184 you need to authenticate. 2185 2186 ``sasl=on|off`` 2187 Require that the client use SASL to authenticate with the spice. 2188 The exact choice of authentication method used is controlled 2189 from the system / user's SASL configuration file for the 'qemu' 2190 service. This is typically found in /etc/sasl2/qemu.conf. If 2191 running QEMU as an unprivileged user, an environment variable 2192 SASL\_CONF\_PATH can be used to make it search alternate 2193 locations for the service config. While some SASL auth methods 2194 can also provide data encryption (eg GSSAPI), it is recommended 2195 that SASL always be combined with the 'tls' and 'x509' settings 2196 to enable use of SSL and server certificates. This ensures a 2197 data encryption preventing compromise of authentication 2198 credentials. 2199 2200 ``disable-ticketing=on|off`` 2201 Allow client connects without authentication. 2202 2203 ``disable-copy-paste=on|off`` 2204 Disable copy paste between the client and the guest. 2205 2206 ``disable-agent-file-xfer=on|off`` 2207 Disable spice-vdagent based file-xfer between the client and the 2208 guest. 2209 2210 ``tls-port=<nr>`` 2211 Set the TCP port spice is listening on for encrypted channels. 2212 2213 ``x509-dir=<dir>`` 2214 Set the x509 file directory. Expects same filenames as -vnc 2215 $display,x509=$dir 2216 2217 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2218 The x509 file names can also be configured individually. 2219 2220 ``tls-ciphers=<list>`` 2221 Specify which ciphers to use. 2222 2223 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2224 Force specific channel to be used with or without TLS 2225 encryption. The options can be specified multiple times to 2226 configure multiple channels. The special name "default" can be 2227 used to set the default mode. For channels which are not 2228 explicitly forced into one mode the spice client is allowed to 2229 pick tls/plaintext as he pleases. 2230 2231 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2232 Configure image compression (lossless). Default is auto\_glz. 2233 2234 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2235 Configure wan image compression (lossy for slow links). Default 2236 is auto. 2237 2238 ``streaming-video=[off|all|filter]`` 2239 Configure video stream detection. Default is off. 2240 2241 ``agent-mouse=[on|off]`` 2242 Enable/disable passing mouse events via vdagent. Default is on. 2243 2244 ``playback-compression=[on|off]`` 2245 Enable/disable audio stream compression (using celt 0.5.1). 2246 Default is on. 2247 2248 ``seamless-migration=[on|off]`` 2249 Enable/disable spice seamless migration. Default is off. 2250 2251 ``gl=[on|off]`` 2252 Enable/disable OpenGL context. Default is off. 2253 2254 ``rendernode=<file>`` 2255 DRM render node for OpenGL rendering. If not specified, it will 2256 pick the first available. (Since 2.9) 2257ERST 2258 2259DEF("portrait", 0, QEMU_OPTION_portrait, 2260 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2261 QEMU_ARCH_ALL) 2262SRST 2263``-portrait`` 2264 Rotate graphical output 90 deg left (only PXA LCD). 2265ERST 2266 2267DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2268 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2269 QEMU_ARCH_ALL) 2270SRST 2271``-rotate deg`` 2272 Rotate graphical output some deg left (only PXA LCD). 2273ERST 2274 2275DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2276 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2277 " select video card type\n", QEMU_ARCH_ALL) 2278SRST 2279``-vga type`` 2280 Select type of VGA card to emulate. Valid values for type are 2281 2282 ``cirrus`` 2283 Cirrus Logic GD5446 Video card. All Windows versions starting 2284 from Windows 95 should recognize and use this graphic card. For 2285 optimal performances, use 16 bit color depth in the guest and 2286 the host OS. (This card was the default before QEMU 2.2) 2287 2288 ``std`` 2289 Standard VGA card with Bochs VBE extensions. If your guest OS 2290 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2291 you want to use high resolution modes (>= 1280x1024x16) then you 2292 should use this option. (This card is the default since QEMU 2293 2.2) 2294 2295 ``vmware`` 2296 VMWare SVGA-II compatible adapter. Use it if you have 2297 sufficiently recent XFree86/XOrg server or Windows guest with a 2298 driver for this card. 2299 2300 ``qxl`` 2301 QXL paravirtual graphic card. It is VGA compatible (including 2302 VESA 2.0 VBE support). Works best with qxl guest drivers 2303 installed though. Recommended choice when using the spice 2304 protocol. 2305 2306 ``tcx`` 2307 (sun4m only) Sun TCX framebuffer. This is the default 2308 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2309 colour depths at a fixed resolution of 1024x768. 2310 2311 ``cg3`` 2312 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2313 framebuffer for sun4m machines available in both 1024x768 2314 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2315 wishing to run older Solaris versions. 2316 2317 ``virtio`` 2318 Virtio VGA card. 2319 2320 ``none`` 2321 Disable VGA card. 2322ERST 2323 2324DEF("full-screen", 0, QEMU_OPTION_full_screen, 2325 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2326SRST 2327``-full-screen`` 2328 Start in full screen. 2329ERST 2330 2331DEF("g", HAS_ARG, QEMU_OPTION_g , 2332 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2333 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2334SRST 2335``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2336 Set the initial graphical resolution and depth (PPC, SPARC only). 2337 2338 For PPC the default is 800x600x32. 2339 2340 For SPARC with the TCX graphics device, the default is 1024x768x8 2341 with the option of 1024x768x24. For cgthree, the default is 2342 1024x768x8 with the option of 1152x900x8 for people who wish to use 2343 OBP. 2344ERST 2345 2346DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2347 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2348SRST 2349``-vnc display[,option[,option[,...]]]`` 2350 Normally, if QEMU is compiled with graphical window support, it 2351 displays output such as guest graphics, guest console, and the QEMU 2352 monitor in a window. With this option, you can have QEMU listen on 2353 VNC display display and redirect the VGA display over the VNC 2354 session. It is very useful to enable the usb tablet device when 2355 using this option (option ``-device usb-tablet``). When using the 2356 VNC display, you must use the ``-k`` parameter to set the keyboard 2357 layout if you are not using en-us. Valid syntax for the display is 2358 2359 ``to=L`` 2360 With this option, QEMU will try next available VNC displays, 2361 until the number L, if the origianlly defined "-vnc display" is 2362 not available, e.g. port 5900+display is already used by another 2363 application. By default, to=0. 2364 2365 ``host:d`` 2366 TCP connections will only be allowed from host on display d. By 2367 convention the TCP port is 5900+d. Optionally, host can be 2368 omitted in which case the server will accept connections from 2369 any host. 2370 2371 ``unix:path`` 2372 Connections will be allowed over UNIX domain sockets where path 2373 is the location of a unix socket to listen for connections on. 2374 2375 ``none`` 2376 VNC is initialized but not started. The monitor ``change`` 2377 command can be used to later start the VNC server. 2378 2379 Following the display value there may be one or more option flags 2380 separated by commas. Valid options are 2381 2382 ``reverse=on|off`` 2383 Connect to a listening VNC client via a "reverse" connection. 2384 The client is specified by the display. For reverse network 2385 connections (host:d,``reverse``), the d argument is a TCP port 2386 number, not a display number. 2387 2388 ``websocket=on|off`` 2389 Opens an additional TCP listening port dedicated to VNC 2390 Websocket connections. If a bare websocket option is given, the 2391 Websocket port is 5700+display. An alternative port can be 2392 specified with the syntax ``websocket``\ =port. 2393 2394 If host is specified connections will only be allowed from this 2395 host. It is possible to control the websocket listen address 2396 independently, using the syntax ``websocket``\ =host:port. 2397 2398 If no TLS credentials are provided, the websocket connection 2399 runs in unencrypted mode. If TLS credentials are provided, the 2400 websocket connection requires encrypted client connections. 2401 2402 ``password=on|off`` 2403 Require that password based authentication is used for client 2404 connections. 2405 2406 The password must be set separately using the ``set_password`` 2407 command in the :ref:`QEMU monitor`. The 2408 syntax to change your password is: 2409 ``set_password <protocol> <password>`` where <protocol> could be 2410 either "vnc" or "spice". 2411 2412 If you would like to change <protocol> password expiration, you 2413 should use ``expire_password <protocol> <expiration-time>`` 2414 where expiration time could be one of the following options: 2415 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2416 make password expire in 60 seconds, or 1335196800 to make 2417 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2418 this date and time). 2419 2420 You can also use keywords "now" or "never" for the expiration 2421 time to allow <protocol> password to expire immediately or never 2422 expire. 2423 2424 ``password-secret=<secret-id>`` 2425 Require that password based authentication is used for client 2426 connections, using the password provided by the ``secret`` 2427 object identified by ``secret-id``. 2428 2429 ``tls-creds=ID`` 2430 Provides the ID of a set of TLS credentials to use to secure the 2431 VNC server. They will apply to both the normal VNC server socket 2432 and the websocket socket (if enabled). Setting TLS credentials 2433 will cause the VNC server socket to enable the VeNCrypt auth 2434 mechanism. The credentials should have been previously created 2435 using the ``-object tls-creds`` argument. 2436 2437 ``tls-authz=ID`` 2438 Provides the ID of the QAuthZ authorization object against which 2439 the client's x509 distinguished name will validated. This object 2440 is only resolved at time of use, so can be deleted and recreated 2441 on the fly while the VNC server is active. If missing, it will 2442 default to denying access. 2443 2444 ``sasl=on|off`` 2445 Require that the client use SASL to authenticate with the VNC 2446 server. The exact choice of authentication method used is 2447 controlled from the system / user's SASL configuration file for 2448 the 'qemu' service. This is typically found in 2449 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2450 an environment variable SASL\_CONF\_PATH can be used to make it 2451 search alternate locations for the service config. While some 2452 SASL auth methods can also provide data encryption (eg GSSAPI), 2453 it is recommended that SASL always be combined with the 'tls' 2454 and 'x509' settings to enable use of SSL and server 2455 certificates. This ensures a data encryption preventing 2456 compromise of authentication credentials. See the 2457 :ref:`VNC security` section in the System Emulation Users Guide 2458 for details on using SASL authentication. 2459 2460 ``sasl-authz=ID`` 2461 Provides the ID of the QAuthZ authorization object against which 2462 the client's SASL username will validated. This object is only 2463 resolved at time of use, so can be deleted and recreated on the 2464 fly while the VNC server is active. If missing, it will default 2465 to denying access. 2466 2467 ``acl=on|off`` 2468 Legacy method for enabling authorization of clients against the 2469 x509 distinguished name and SASL username. It results in the 2470 creation of two ``authz-list`` objects with IDs of 2471 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2472 objects must be configured with the HMP ACL commands. 2473 2474 This option is deprecated and should no longer be used. The new 2475 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2476 2477 ``lossy=on|off`` 2478 Enable lossy compression methods (gradient, JPEG, ...). If this 2479 option is set, VNC client may receive lossy framebuffer updates 2480 depending on its encoding settings. Enabling this option can 2481 save a lot of bandwidth at the expense of quality. 2482 2483 ``non-adaptive=on|off`` 2484 Disable adaptive encodings. Adaptive encodings are enabled by 2485 default. An adaptive encoding will try to detect frequently 2486 updated screen regions, and send updates in these regions using 2487 a lossy encoding (like JPEG). This can be really helpful to save 2488 bandwidth when playing videos. Disabling adaptive encodings 2489 restores the original static behavior of encodings like Tight. 2490 2491 ``share=[allow-exclusive|force-shared|ignore]`` 2492 Set display sharing policy. 'allow-exclusive' allows clients to 2493 ask for exclusive access. As suggested by the rfb spec this is 2494 implemented by dropping other connections. Connecting multiple 2495 clients in parallel requires all clients asking for a shared 2496 session (vncviewer: -shared switch). This is the default. 2497 'force-shared' disables exclusive client access. Useful for 2498 shared desktop sessions, where you don't want someone forgetting 2499 specify -shared disconnect everybody else. 'ignore' completely 2500 ignores the shared flag and allows everybody connect 2501 unconditionally. Doesn't conform to the rfb spec but is 2502 traditional QEMU behavior. 2503 2504 ``key-delay-ms`` 2505 Set keyboard delay, for key down and key up events, in 2506 milliseconds. Default is 10. Keyboards are low-bandwidth 2507 devices, so this slowdown can help the device and guest to keep 2508 up and not lose events in case events are arriving in bulk. 2509 Possible causes for the latter are flaky network connections, or 2510 scripts for automated testing. 2511 2512 ``audiodev=audiodev`` 2513 Use the specified audiodev when the VNC client requests audio 2514 transmission. When not using an -audiodev argument, this option 2515 must be omitted, otherwise is must be present and specify a 2516 valid audiodev. 2517 2518 ``power-control=on|off`` 2519 Permit the remote client to issue shutdown, reboot or reset power 2520 control requests. 2521ERST 2522 2523ARCHHEADING(, QEMU_ARCH_I386) 2524 2525ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2526 2527DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2528 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2529 QEMU_ARCH_I386) 2530SRST 2531``-win2k-hack`` 2532 Use it when installing Windows 2000 to avoid a disk full bug. After 2533 Windows 2000 is installed, you no longer need this option (this 2534 option slows down the IDE transfers). 2535ERST 2536 2537DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2538 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2539 QEMU_ARCH_I386) 2540SRST 2541``-no-fd-bootchk`` 2542 Disable boot signature checking for floppy disks in BIOS. May be 2543 needed to boot from old floppy disks. 2544ERST 2545 2546DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2547 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2548SRST 2549``-no-acpi`` 2550 Disable ACPI (Advanced Configuration and Power Interface) support. 2551 Use it if your guest OS complains about ACPI problems (PC target 2552 machine only). 2553ERST 2554 2555DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2556 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2557SRST 2558``-no-hpet`` 2559 Disable HPET support. 2560ERST 2561 2562DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2563 "-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" 2564 " ACPI table description\n", QEMU_ARCH_I386) 2565SRST 2566``-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]...]`` 2567 Add ACPI table with specified header fields and context from 2568 specified files. For file=, take whole ACPI table from the specified 2569 files, including all ACPI headers (possible overridden by other 2570 options). For data=, only data portion of the table is used, all 2571 header information is specified in the command line. If a SLIC table 2572 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2573 fields will override the same in the RSDT and the FADT (a.k.a. 2574 FACP), in order to ensure the field matches required by the 2575 Microsoft SLIC spec and the ACPI spec. 2576ERST 2577 2578DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2579 "-smbios file=binary\n" 2580 " load SMBIOS entry from binary file\n" 2581 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2582 " [,uefi=on|off]\n" 2583 " specify SMBIOS type 0 fields\n" 2584 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2585 " [,uuid=uuid][,sku=str][,family=str]\n" 2586 " specify SMBIOS type 1 fields\n" 2587 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2588 " [,asset=str][,location=str]\n" 2589 " specify SMBIOS type 2 fields\n" 2590 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2591 " [,sku=str]\n" 2592 " specify SMBIOS type 3 fields\n" 2593 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2594 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2595 " [,processor-id=%d]\n" 2596 " specify SMBIOS type 4 fields\n" 2597 "-smbios type=11[,value=str][,path=filename]\n" 2598 " specify SMBIOS type 11 fields\n" 2599 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2600 " [,asset=str][,part=str][,speed=%d]\n" 2601 " specify SMBIOS type 17 fields\n" 2602 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2603 " specify SMBIOS type 41 fields\n", 2604 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2605SRST 2606``-smbios file=binary`` 2607 Load SMBIOS entry from binary file. 2608 2609``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2610 Specify SMBIOS type 0 fields 2611 2612``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2613 Specify SMBIOS type 1 fields 2614 2615``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2616 Specify SMBIOS type 2 fields 2617 2618``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2619 Specify SMBIOS type 3 fields 2620 2621``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2622 Specify SMBIOS type 4 fields 2623 2624``-smbios type=11[,value=str][,path=filename]`` 2625 Specify SMBIOS type 11 fields 2626 2627 This argument can be repeated multiple times, and values are added in the order they are parsed. 2628 Applications intending to use OEM strings data are encouraged to use their application name as 2629 a prefix for the value string. This facilitates passing information for multiple applications 2630 concurrently. 2631 2632 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2633 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2634 2635 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2636 the SMBIOS table in the order in which they appear. 2637 2638 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2639 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2640 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2641 data set, for example, by specifying the serial ID of a block device. 2642 2643 An example passing three strings is 2644 2645 .. parsed-literal:: 2646 2647 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2648 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2649 path=/some/file/with/oemstringsdata.txt 2650 2651 In the guest OS this is visible with the ``dmidecode`` command 2652 2653 .. parsed-literal:: 2654 2655 $ dmidecode -t 11 2656 Handle 0x0E00, DMI type 11, 5 bytes 2657 OEM Strings 2658 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2659 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2660 String 3: myapp:some extra data 2661 2662 2663``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2664 Specify SMBIOS type 17 fields 2665 2666``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2667 Specify SMBIOS type 41 fields 2668 2669 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2670 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2671 position on the PCI bus. 2672 2673 Here is an example of use: 2674 2675 .. parsed-literal:: 2676 2677 -netdev user,id=internet \\ 2678 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2679 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2680 2681 In the guest OS, the device should then appear as ``eno1``: 2682 2683 ..parsed-literal:: 2684 2685 $ ip -brief l 2686 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2687 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2688 2689 Currently, the PCI device has to be attached to the root bus. 2690 2691ERST 2692 2693DEFHEADING() 2694 2695DEFHEADING(Network options:) 2696 2697DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2698#ifdef CONFIG_SLIRP 2699 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2700 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2701 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2702 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2703 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2704#ifndef _WIN32 2705 "[,smb=dir[,smbserver=addr]]\n" 2706#endif 2707 " configure a user mode network backend with ID 'str',\n" 2708 " its DHCP server and optional services\n" 2709#endif 2710#ifdef _WIN32 2711 "-netdev tap,id=str,ifname=name\n" 2712 " configure a host TAP network backend with ID 'str'\n" 2713#else 2714 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2715 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2716 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2717 " [,poll-us=n]\n" 2718 " configure a host TAP network backend with ID 'str'\n" 2719 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2720 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2721 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2722 " to deconfigure it\n" 2723 " use '[down]script=no' to disable script execution\n" 2724 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2725 " configure it\n" 2726 " use 'fd=h' to connect to an already opened TAP interface\n" 2727 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2728 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2729 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2730 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2731 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2732 " use vhost=on to enable experimental in kernel accelerator\n" 2733 " (only has effect for virtio guests which use MSIX)\n" 2734 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2735 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2736 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2737 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2738 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2739 " spent on busy polling for vhost net\n" 2740 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2741 " configure a host TAP network backend with ID 'str' that is\n" 2742 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2743 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2744#endif 2745#ifdef __linux__ 2746 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2747 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2748 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2749 " [,rxcookie=rxcookie][,offset=offset]\n" 2750 " configure a network backend with ID 'str' connected to\n" 2751 " an Ethernet over L2TPv3 pseudowire.\n" 2752 " Linux kernel 3.3+ as well as most routers can talk\n" 2753 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2754 " VM to a router and even VM to Host. It is a nearly-universal\n" 2755 " standard (RFC3931). Note - this implementation uses static\n" 2756 " pre-configured tunnels (same as the Linux kernel).\n" 2757 " use 'src=' to specify source address\n" 2758 " use 'dst=' to specify destination address\n" 2759 " use 'udp=on' to specify udp encapsulation\n" 2760 " use 'srcport=' to specify source udp port\n" 2761 " use 'dstport=' to specify destination udp port\n" 2762 " use 'ipv6=on' to force v6\n" 2763 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2764 " well as a weak security measure\n" 2765 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2766 " use 'txcookie=0x012345678' to specify a txcookie\n" 2767 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2768 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2769 " use 'pincounter=on' to work around broken counter handling in peer\n" 2770 " use 'offset=X' to add an extra offset between header and data\n" 2771#endif 2772 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2773 " configure a network backend to connect to another network\n" 2774 " using a socket connection\n" 2775 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2776 " configure a network backend to connect to a multicast maddr and port\n" 2777 " use 'localaddr=addr' to specify the host address to send packets from\n" 2778 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2779 " configure a network backend to connect to another network\n" 2780 " using an UDP tunnel\n" 2781#ifdef CONFIG_VDE 2782 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2783 " configure a network backend to connect to port 'n' of a vde switch\n" 2784 " running on host and listening for incoming connections on 'socketpath'.\n" 2785 " Use group 'groupname' and mode 'octalmode' to change default\n" 2786 " ownership and permissions for communication port.\n" 2787#endif 2788#ifdef CONFIG_NETMAP 2789 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2790 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2791 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2792 " netmap device, defaults to '/dev/netmap')\n" 2793#endif 2794#ifdef CONFIG_POSIX 2795 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2796 " configure a vhost-user network, backed by a chardev 'dev'\n" 2797#endif 2798#ifdef __linux__ 2799 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2800 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2801#endif 2802 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2803 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2804DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2805 "-nic [tap|bridge|" 2806#ifdef CONFIG_SLIRP 2807 "user|" 2808#endif 2809#ifdef __linux__ 2810 "l2tpv3|" 2811#endif 2812#ifdef CONFIG_VDE 2813 "vde|" 2814#endif 2815#ifdef CONFIG_NETMAP 2816 "netmap|" 2817#endif 2818#ifdef CONFIG_POSIX 2819 "vhost-user|" 2820#endif 2821 "socket][,option][,...][mac=macaddr]\n" 2822 " initialize an on-board / default host NIC (using MAC address\n" 2823 " macaddr) and connect it to the given host network backend\n" 2824 "-nic none use it alone to have zero network devices (the default is to\n" 2825 " provided a 'user' network connection)\n", 2826 QEMU_ARCH_ALL) 2827DEF("net", HAS_ARG, QEMU_OPTION_net, 2828 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2829 " configure or create an on-board (or machine default) NIC and\n" 2830 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2831 "-net [" 2832#ifdef CONFIG_SLIRP 2833 "user|" 2834#endif 2835 "tap|" 2836 "bridge|" 2837#ifdef CONFIG_VDE 2838 "vde|" 2839#endif 2840#ifdef CONFIG_NETMAP 2841 "netmap|" 2842#endif 2843 "socket][,option][,option][,...]\n" 2844 " old way to initialize a host network interface\n" 2845 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2846SRST 2847``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2848 This option is a shortcut for configuring both the on-board 2849 (default) guest NIC hardware and the host network backend in one go. 2850 The host backend options are the same as with the corresponding 2851 ``-netdev`` options below. The guest NIC model can be set with 2852 ``model=modelname``. Use ``model=help`` to list the available device 2853 types. The hardware MAC address can be set with ``mac=macaddr``. 2854 2855 The following two example do exactly the same, to show how ``-nic`` 2856 can be used to shorten the command line length: 2857 2858 .. parsed-literal:: 2859 2860 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2861 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2862 2863``-nic none`` 2864 Indicate that no network devices should be configured. It is used to 2865 override the default configuration (default NIC with "user" host 2866 network backend) which is activated if no other networking options 2867 are provided. 2868 2869``-netdev user,id=id[,option][,option][,...]`` 2870 Configure user mode host network backend which requires no 2871 administrator privilege to run. Valid options are: 2872 2873 ``id=id`` 2874 Assign symbolic name for use in monitor commands. 2875 2876 ``ipv4=on|off and ipv6=on|off`` 2877 Specify that either IPv4 or IPv6 must be enabled. If neither is 2878 specified both protocols are enabled. 2879 2880 ``net=addr[/mask]`` 2881 Set IP network address the guest will see. Optionally specify 2882 the netmask, either in the form a.b.c.d or as number of valid 2883 top-most bits. Default is 10.0.2.0/24. 2884 2885 ``host=addr`` 2886 Specify the guest-visible address of the host. Default is the 2887 2nd IP in the guest network, i.e. x.x.x.2. 2888 2889 ``ipv6-net=addr[/int]`` 2890 Set IPv6 network address the guest will see (default is 2891 fec0::/64). The network prefix is given in the usual hexadecimal 2892 IPv6 address notation. The prefix size is optional, and is given 2893 as the number of valid top-most bits (default is 64). 2894 2895 ``ipv6-host=addr`` 2896 Specify the guest-visible IPv6 address of the host. Default is 2897 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2898 2899 ``restrict=on|off`` 2900 If this option is enabled, the guest will be isolated, i.e. it 2901 will not be able to contact the host and no guest IP packets 2902 will be routed over the host to the outside. This option does 2903 not affect any explicitly set forwarding rules. 2904 2905 ``hostname=name`` 2906 Specifies the client hostname reported by the built-in DHCP 2907 server. 2908 2909 ``dhcpstart=addr`` 2910 Specify the first of the 16 IPs the built-in DHCP server can 2911 assign. Default is the 15th to 31st IP in the guest network, 2912 i.e. x.x.x.15 to x.x.x.31. 2913 2914 ``dns=addr`` 2915 Specify the guest-visible address of the virtual nameserver. The 2916 address must be different from the host address. Default is the 2917 3rd IP in the guest network, i.e. x.x.x.3. 2918 2919 ``ipv6-dns=addr`` 2920 Specify the guest-visible address of the IPv6 virtual 2921 nameserver. The address must be different from the host address. 2922 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2923 2924 ``dnssearch=domain`` 2925 Provides an entry for the domain-search list sent by the 2926 built-in DHCP server. More than one domain suffix can be 2927 transmitted by specifying this option multiple times. If 2928 supported, this will cause the guest to automatically try to 2929 append the given domain suffix(es) in case a domain name can not 2930 be resolved. 2931 2932 Example: 2933 2934 .. parsed-literal:: 2935 2936 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2937 2938 ``domainname=domain`` 2939 Specifies the client domain name reported by the built-in DHCP 2940 server. 2941 2942 ``tftp=dir`` 2943 When using the user mode network stack, activate a built-in TFTP 2944 server. The files in dir will be exposed as the root of a TFTP 2945 server. The TFTP client on the guest must be configured in 2946 binary mode (use the command ``bin`` of the Unix TFTP client). 2947 2948 ``tftp-server-name=name`` 2949 In BOOTP reply, broadcast name as the "TFTP server name" 2950 (RFC2132 option 66). This can be used to advise the guest to 2951 load boot files or configurations from a different server than 2952 the host address. 2953 2954 ``bootfile=file`` 2955 When using the user mode network stack, broadcast file as the 2956 BOOTP filename. In conjunction with ``tftp``, this can be used 2957 to network boot a guest from a local directory. 2958 2959 Example (using pxelinux): 2960 2961 .. parsed-literal:: 2962 2963 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2964 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2965 2966 ``smb=dir[,smbserver=addr]`` 2967 When using the user mode network stack, activate a built-in SMB 2968 server so that Windows OSes can access to the host files in 2969 ``dir`` transparently. The IP address of the SMB server can be 2970 set to addr. By default the 4th IP in the guest network is used, 2971 i.e. x.x.x.4. 2972 2973 In the guest Windows OS, the line: 2974 2975 :: 2976 2977 10.0.2.4 smbserver 2978 2979 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2980 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2981 NT/2000). 2982 2983 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2984 2985 Note that a SAMBA server must be installed on the host OS. 2986 2987 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2988 Redirect incoming TCP or UDP connections to the host port 2989 hostport to the guest IP address guestaddr on guest port 2990 guestport. If guestaddr is not specified, its value is x.x.x.15 2991 (default first address given by the built-in DHCP server). By 2992 specifying hostaddr, the rule can be bound to a specific host 2993 interface. If no connection type is set, TCP is used. This 2994 option can be given multiple times. 2995 2996 For example, to redirect host X11 connection from screen 1 to 2997 guest screen 0, use the following: 2998 2999 .. parsed-literal:: 3000 3001 # on the host 3002 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3003 # this host xterm should open in the guest X11 server 3004 xterm -display :1 3005 3006 To redirect telnet connections from host port 5555 to telnet 3007 port on the guest, use the following: 3008 3009 .. parsed-literal:: 3010 3011 # on the host 3012 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3013 telnet localhost 5555 3014 3015 Then when you use on the host ``telnet localhost 5555``, you 3016 connect to the guest telnet server. 3017 3018 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3019 Forward guest TCP connections to the IP address server on port 3020 port to the character device dev or to a program executed by 3021 cmd:command which gets spawned for each connection. This option 3022 can be given multiple times. 3023 3024 You can either use a chardev directly and have that one used 3025 throughout QEMU's lifetime, like in the following example: 3026 3027 .. parsed-literal:: 3028 3029 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3030 # the guest accesses it 3031 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3032 3033 Or you can execute a command on every TCP connection established 3034 by the guest, so that QEMU behaves similar to an inetd process 3035 for that virtual server: 3036 3037 .. parsed-literal:: 3038 3039 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3040 # and connect the TCP stream to its stdin/stdout 3041 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3042 3043``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3044 Configure a host TAP network backend with ID id. 3045 3046 Use the network script file to configure it and the network script 3047 dfile to deconfigure it. If name is not provided, the OS 3048 automatically provides one. The default network configure script is 3049 ``/etc/qemu-ifup`` and the default network deconfigure script is 3050 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3051 disable script execution. 3052 3053 If running QEMU as an unprivileged user, use the network helper 3054 to configure the TAP interface and attach it to the bridge. 3055 The default network helper executable is 3056 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3057 ``br0``. 3058 3059 ``fd``\ =h can be used to specify the handle of an already opened 3060 host TAP interface. 3061 3062 Examples: 3063 3064 .. parsed-literal:: 3065 3066 #launch a QEMU instance with the default network script 3067 |qemu_system| linux.img -nic tap 3068 3069 .. parsed-literal:: 3070 3071 #launch a QEMU instance with two NICs, each one connected 3072 #to a TAP device 3073 |qemu_system| linux.img \\ 3074 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3075 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3076 3077 .. parsed-literal:: 3078 3079 #launch a QEMU instance with the default network helper to 3080 #connect a TAP device to bridge br0 3081 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3082 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3083 3084``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3085 Connect a host TAP network interface to a host bridge device. 3086 3087 Use the network helper helper to configure the TAP interface and 3088 attach it to the bridge. The default network helper executable is 3089 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3090 ``br0``. 3091 3092 Examples: 3093 3094 .. parsed-literal:: 3095 3096 #launch a QEMU instance with the default network helper to 3097 #connect a TAP device to bridge br0 3098 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3099 3100 .. parsed-literal:: 3101 3102 #launch a QEMU instance with the default network helper to 3103 #connect a TAP device to bridge qemubr0 3104 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3105 3106``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3107 This host network backend can be used to connect the guest's network 3108 to another QEMU virtual machine using a TCP socket connection. If 3109 ``listen`` is specified, QEMU waits for incoming connections on port 3110 (host is optional). ``connect`` is used to connect to another QEMU 3111 instance using the ``listen`` option. ``fd``\ =h specifies an 3112 already opened TCP socket. 3113 3114 Example: 3115 3116 .. parsed-literal:: 3117 3118 # launch a first QEMU instance 3119 |qemu_system| linux.img \\ 3120 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3121 -netdev socket,id=n1,listen=:1234 3122 # connect the network of this instance to the network of the first instance 3123 |qemu_system| linux.img \\ 3124 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3125 -netdev socket,id=n2,connect=127.0.0.1:1234 3126 3127``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3128 Configure a socket host network backend to share the guest's network 3129 traffic with another QEMU virtual machines using a UDP multicast 3130 socket, effectively making a bus for every QEMU with same multicast 3131 address maddr and port. NOTES: 3132 3133 1. Several QEMU can be running on different hosts and share same bus 3134 (assuming correct multicast setup for these hosts). 3135 3136 2. mcast support is compatible with User Mode Linux (argument 3137 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3138 3139 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3140 3141 Example: 3142 3143 .. parsed-literal:: 3144 3145 # launch one QEMU instance 3146 |qemu_system| linux.img \\ 3147 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3148 -netdev socket,id=n1,mcast=230.0.0.1:1234 3149 # launch another QEMU instance on same "bus" 3150 |qemu_system| linux.img \\ 3151 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3152 -netdev socket,id=n2,mcast=230.0.0.1:1234 3153 # launch yet another QEMU instance on same "bus" 3154 |qemu_system| linux.img \\ 3155 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3156 -netdev socket,id=n3,mcast=230.0.0.1:1234 3157 3158 Example (User Mode Linux compat.): 3159 3160 .. parsed-literal:: 3161 3162 # launch QEMU instance (note mcast address selected is UML's default) 3163 |qemu_system| linux.img \\ 3164 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3165 -netdev socket,id=n1,mcast=239.192.168.1:1102 3166 # launch UML 3167 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3168 3169 Example (send packets from host's 1.2.3.4): 3170 3171 .. parsed-literal:: 3172 3173 |qemu_system| linux.img \\ 3174 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3175 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3176 3177``-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]`` 3178 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3179 is a popular protocol to transport Ethernet (and other Layer 2) data 3180 frames between two systems. It is present in routers, firewalls and 3181 the Linux kernel (from version 3.3 onwards). 3182 3183 This transport allows a VM to communicate to another VM, router or 3184 firewall directly. 3185 3186 ``src=srcaddr`` 3187 source address (mandatory) 3188 3189 ``dst=dstaddr`` 3190 destination address (mandatory) 3191 3192 ``udp`` 3193 select udp encapsulation (default is ip). 3194 3195 ``srcport=srcport`` 3196 source udp port. 3197 3198 ``dstport=dstport`` 3199 destination udp port. 3200 3201 ``ipv6`` 3202 force v6, otherwise defaults to v4. 3203 3204 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3205 Cookies are a weak form of security in the l2tpv3 specification. 3206 Their function is mostly to prevent misconfiguration. By default 3207 they are 32 bit. 3208 3209 ``cookie64`` 3210 Set cookie size to 64 bit instead of the default 32 3211 3212 ``counter=off`` 3213 Force a 'cut-down' L2TPv3 with no counter as in 3214 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3215 3216 ``pincounter=on`` 3217 Work around broken counter handling in peer. This may also help 3218 on networks which have packet reorder. 3219 3220 ``offset=offset`` 3221 Add an extra offset between header and data 3222 3223 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3224 the bridge br-lan on the remote Linux host 1.2.3.4: 3225 3226 .. parsed-literal:: 3227 3228 # Setup tunnel on linux host using raw ip as encapsulation 3229 # on 1.2.3.4 3230 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3231 encap udp udp_sport 16384 udp_dport 16384 3232 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3233 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3234 ifconfig vmtunnel0 mtu 1500 3235 ifconfig vmtunnel0 up 3236 brctl addif br-lan vmtunnel0 3237 3238 3239 # on 4.3.2.1 3240 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3241 3242 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3243 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3244 3245``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3246 Configure VDE backend to connect to PORT n of a vde switch running 3247 on host and listening for incoming connections on socketpath. Use 3248 GROUP groupname and MODE octalmode to change default ownership and 3249 permissions for communication port. This option is only available if 3250 QEMU has been compiled with vde support enabled. 3251 3252 Example: 3253 3254 .. parsed-literal:: 3255 3256 # launch vde switch 3257 vde_switch -F -sock /tmp/myswitch 3258 # launch QEMU instance 3259 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3260 3261``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3262 Establish a vhost-user netdev, backed by a chardev id. The chardev 3263 should be a unix domain socket backed one. The vhost-user uses a 3264 specifically defined protocol to pass vhost ioctl replacement 3265 messages to an application on the other end of the socket. On 3266 non-MSIX guests, the feature can be forced with vhostforce. Use 3267 'queues=n' to specify the number of queues to be created for 3268 multiqueue vhost-user. 3269 3270 Example: 3271 3272 :: 3273 3274 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3275 -numa node,memdev=mem \ 3276 -chardev socket,id=chr0,path=/path/to/socket \ 3277 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3278 -device virtio-net-pci,netdev=net0 3279 3280``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3281 Establish a vhost-vdpa netdev. 3282 3283 vDPA device is a device that uses a datapath which complies with 3284 the virtio specifications with a vendor specific control path. 3285 vDPA devices can be both physically located on the hardware or 3286 emulated by software. 3287 3288``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3289 Create a hub port on the emulated hub with ID hubid. 3290 3291 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3292 instead of a single netdev. Alternatively, you can also connect the 3293 hubport to another netdev with ID nd by using the ``netdev=nd`` 3294 option. 3295 3296``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3297 Legacy option to configure or create an on-board (or machine 3298 default) Network Interface Card(NIC) and connect it either to the 3299 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3300 If model is omitted, then the default NIC model associated with the 3301 machine type is used. Note that the default NIC model may change in 3302 future QEMU releases, so it is highly recommended to always specify 3303 a model. Optionally, the MAC address can be changed to mac, the 3304 device address set to addr (PCI cards only), and a name can be 3305 assigned for use in monitor commands. Optionally, for PCI cards, you 3306 can specify the number v of MSI-X vectors that the card should have; 3307 this option currently only affects virtio cards; set v = 0 to 3308 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3309 created. QEMU can emulate several different models of network card. 3310 Use ``-net nic,model=help`` for a list of available devices for your 3311 target. 3312 3313``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3314 Configure a host network backend (with the options corresponding to 3315 the same ``-netdev`` option) and connect it to the emulated hub 0 3316 (the default hub). Use name to specify the name of the hub port. 3317ERST 3318 3319DEFHEADING() 3320 3321DEFHEADING(Character device options:) 3322 3323DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3324 "-chardev help\n" 3325 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3326 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3327 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3328 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3329 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3330 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3331 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3332 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3333 " [,logfile=PATH][,logappend=on|off]\n" 3334 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3335 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3336 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3337 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3338 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3339 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3340#ifdef _WIN32 3341 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3342 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3343#else 3344 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3345 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3346#endif 3347#ifdef CONFIG_BRLAPI 3348 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3349#endif 3350#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3351 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3352 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3353 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3354#endif 3355#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3356 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3357 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3358#endif 3359#if defined(CONFIG_SPICE) 3360 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3361 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3362#endif 3363 , QEMU_ARCH_ALL 3364) 3365 3366SRST 3367The general form of a character device option is: 3368 3369``-chardev backend,id=id[,mux=on|off][,options]`` 3370 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3371 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3372 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3373 ``spicevmc``, ``spiceport``. The specific backend will determine the 3374 applicable options. 3375 3376 Use ``-chardev help`` to print all available chardev backend types. 3377 3378 All devices must have an id, which can be any string up to 127 3379 characters long. It is used to uniquely identify this device in 3380 other command line directives. 3381 3382 A character device may be used in multiplexing mode by multiple 3383 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3384 a "1:N" device, and here the "1" end is your specified chardev 3385 backend, and the "N" end is the various parts of QEMU that can talk 3386 to a chardev. If you create a chardev with ``id=myid`` and 3387 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3388 and you can then configure multiple front ends to use that chardev 3389 ID for their input/output. Up to four different front ends can be 3390 connected to a single multiplexed chardev. (Without multiplexing 3391 enabled, a chardev can only be used by a single front end.) For 3392 instance you could use this to allow a single stdio chardev to be 3393 used by two serial ports and the QEMU monitor: 3394 3395 :: 3396 3397 -chardev stdio,mux=on,id=char0 \ 3398 -mon chardev=char0,mode=readline \ 3399 -serial chardev:char0 \ 3400 -serial chardev:char0 3401 3402 You can have more than one multiplexer in a system configuration; 3403 for instance you could have a TCP port multiplexed between UART 0 3404 and UART 1, and stdio multiplexed between the QEMU monitor and a 3405 parallel port: 3406 3407 :: 3408 3409 -chardev stdio,mux=on,id=char0 \ 3410 -mon chardev=char0,mode=readline \ 3411 -parallel chardev:char0 \ 3412 -chardev tcp,...,mux=on,id=char1 \ 3413 -serial chardev:char1 \ 3414 -serial chardev:char1 3415 3416 When you're using a multiplexed character device, some escape 3417 sequences are interpreted in the input. See the chapter about 3418 :ref:`keys in the character backend multiplexer` in the 3419 System Emulation Users Guide for more details. 3420 3421 Note that some other command line options may implicitly create 3422 multiplexed character backends; for instance ``-serial mon:stdio`` 3423 creates a multiplexed stdio backend connected to the serial port and 3424 the QEMU monitor, and ``-nographic`` also multiplexes the console 3425 and the monitor to stdio. 3426 3427 There is currently no support for multiplexing in the other 3428 direction (where a single QEMU front end takes input and output from 3429 multiple chardevs). 3430 3431 Every backend supports the ``logfile`` option, which supplies the 3432 path to a file to record all data transmitted via the backend. The 3433 ``logappend`` option controls whether the log file will be truncated 3434 or appended to when opened. 3435 3436The available backends are: 3437 3438``-chardev null,id=id`` 3439 A void device. This device will not emit any data, and will drop any 3440 data it receives. The null backend does not take any options. 3441 3442``-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]`` 3443 Create a two-way stream socket, which can be either a TCP or a unix 3444 socket. A unix socket will be created if ``path`` is specified. 3445 Behaviour is undefined if TCP options are specified for a unix 3446 socket. 3447 3448 ``server=on|off`` specifies that the socket shall be a listening socket. 3449 3450 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3451 to connect to a listening socket. 3452 3453 ``telnet=on|off`` specifies that traffic on the socket should interpret 3454 telnet escape sequences. 3455 3456 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3457 communication. 3458 3459 ``reconnect`` sets the timeout for reconnecting on non-server 3460 sockets when the remote end goes away. qemu will delay this many 3461 seconds and then attempt to reconnect. Zero disables reconnecting, 3462 and is the default. 3463 3464 ``tls-creds`` requests enablement of the TLS protocol for 3465 encryption, and specifies the id of the TLS credentials to use for 3466 the handshake. The credentials must be previously created with the 3467 ``-object tls-creds`` argument. 3468 3469 ``tls-auth`` provides the ID of the QAuthZ authorization object 3470 against which the client's x509 distinguished name will be 3471 validated. This object is only resolved at time of use, so can be 3472 deleted and recreated on the fly while the chardev server is active. 3473 If missing, it will default to denying access. 3474 3475 TCP and unix socket options are given below: 3476 3477 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3478 ``host`` for a listening socket specifies the local address to 3479 be bound. For a connecting socket species the remote host to 3480 connect to. ``host`` is optional for listening sockets. If not 3481 specified it defaults to ``0.0.0.0``. 3482 3483 ``port`` for a listening socket specifies the local port to be 3484 bound. For a connecting socket specifies the port on the remote 3485 host to connect to. ``port`` can be given as either a port 3486 number or a service name. ``port`` is required. 3487 3488 ``to`` is only relevant to listening sockets. If it is 3489 specified, and ``port`` cannot be bound, QEMU will attempt to 3490 bind to subsequent ports up to and including ``to`` until it 3491 succeeds. ``to`` must be specified as a port number. 3492 3493 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3494 or IPv6 must be used. If neither is specified the socket may 3495 use either protocol. 3496 3497 ``nodelay=on|off`` disables the Nagle algorithm. 3498 3499 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3500 ``path`` specifies the local path of the unix socket. ``path`` 3501 is required. 3502 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3503 rather than the filesystem. Optional, defaults to false. 3504 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3505 rather than the full sun_path length. Optional, defaults to true. 3506 3507``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3508 Sends all traffic from the guest to a remote host over UDP. 3509 3510 ``host`` specifies the remote host to connect to. If not specified 3511 it defaults to ``localhost``. 3512 3513 ``port`` specifies the port on the remote host to connect to. 3514 ``port`` is required. 3515 3516 ``localaddr`` specifies the local address to bind to. If not 3517 specified it defaults to ``0.0.0.0``. 3518 3519 ``localport`` specifies the local port to bind to. If not specified 3520 any available local port will be used. 3521 3522 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3523 If neither is specified the device may use either protocol. 3524 3525``-chardev msmouse,id=id`` 3526 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3527 does not take any options. 3528 3529``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3530 Connect to a QEMU text console. ``vc`` may optionally be given a 3531 specific size. 3532 3533 ``width`` and ``height`` specify the width and height respectively 3534 of the console, in pixels. 3535 3536 ``cols`` and ``rows`` specify that the console be sized to fit a 3537 text console with the given dimensions. 3538 3539``-chardev ringbuf,id=id[,size=size]`` 3540 Create a ring buffer with fixed size ``size``. size must be a power 3541 of two and defaults to ``64K``. 3542 3543``-chardev file,id=id,path=path`` 3544 Log all traffic received from the guest to a file. 3545 3546 ``path`` specifies the path of the file to be opened. This file will 3547 be created if it does not already exist, and overwritten if it does. 3548 ``path`` is required. 3549 3550``-chardev pipe,id=id,path=path`` 3551 Create a two-way connection to the guest. The behaviour differs 3552 slightly between Windows hosts and other hosts: 3553 3554 On Windows, a single duplex pipe will be created at 3555 ``\\.pipe\path``. 3556 3557 On other hosts, 2 pipes will be created called ``path.in`` and 3558 ``path.out``. Data written to ``path.in`` will be received by the 3559 guest. Data written by the guest can be read from ``path.out``. QEMU 3560 will not create these fifos, and requires them to be present. 3561 3562 ``path`` forms part of the pipe path as described above. ``path`` is 3563 required. 3564 3565``-chardev console,id=id`` 3566 Send traffic from the guest to QEMU's standard output. ``console`` 3567 does not take any options. 3568 3569 ``console`` is only available on Windows hosts. 3570 3571``-chardev serial,id=id,path=path`` 3572 Send traffic from the guest to a serial device on the host. 3573 3574 On Unix hosts serial will actually accept any tty device, not only 3575 serial lines. 3576 3577 ``path`` specifies the name of the serial device to open. 3578 3579``-chardev pty,id=id`` 3580 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3581 does not take any options. 3582 3583 ``pty`` is not available on Windows hosts. 3584 3585``-chardev stdio,id=id[,signal=on|off]`` 3586 Connect to standard input and standard output of the QEMU process. 3587 3588 ``signal`` controls if signals are enabled on the terminal, that 3589 includes exiting QEMU with the key sequence Control-c. This option 3590 is enabled by default, use ``signal=off`` to disable it. 3591 3592``-chardev braille,id=id`` 3593 Connect to a local BrlAPI server. ``braille`` does not take any 3594 options. 3595 3596``-chardev tty,id=id,path=path`` 3597 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3598 and DragonFlyBSD hosts. It is an alias for ``serial``. 3599 3600 ``path`` specifies the path to the tty. ``path`` is required. 3601 3602``-chardev parallel,id=id,path=path`` 3603 \ 3604``-chardev parport,id=id,path=path`` 3605 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3606 hosts. 3607 3608 Connect to a local parallel port. 3609 3610 ``path`` specifies the path to the parallel port device. ``path`` is 3611 required. 3612 3613``-chardev spicevmc,id=id,debug=debug,name=name`` 3614 ``spicevmc`` is only available when spice support is built in. 3615 3616 ``debug`` debug level for spicevmc 3617 3618 ``name`` name of spice channel to connect to 3619 3620 Connect to a spice virtual machine channel, such as vdiport. 3621 3622``-chardev spiceport,id=id,debug=debug,name=name`` 3623 ``spiceport`` is only available when spice support is built in. 3624 3625 ``debug`` debug level for spicevmc 3626 3627 ``name`` name of spice port to connect to 3628 3629 Connect to a spice port, allowing a Spice client to handle the 3630 traffic identified by a name (preferably a fqdn). 3631ERST 3632 3633DEFHEADING() 3634 3635#ifdef CONFIG_TPM 3636DEFHEADING(TPM device options:) 3637 3638DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3639 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3640 " use path to provide path to a character device; default is /dev/tpm0\n" 3641 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3642 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3643 "-tpmdev emulator,id=id,chardev=dev\n" 3644 " configure the TPM device using chardev backend\n", 3645 QEMU_ARCH_ALL) 3646SRST 3647The general form of a TPM device option is: 3648 3649``-tpmdev backend,id=id[,options]`` 3650 The specific backend type will determine the applicable options. The 3651 ``-tpmdev`` option creates the TPM backend and requires a 3652 ``-device`` option that specifies the TPM frontend interface model. 3653 3654 Use ``-tpmdev help`` to print all available TPM backend types. 3655 3656The available backends are: 3657 3658``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3659 (Linux-host only) Enable access to the host's TPM using the 3660 passthrough driver. 3661 3662 ``path`` specifies the path to the host's TPM device, i.e., on a 3663 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3664 default ``/dev/tpm0`` is used. 3665 3666 ``cancel-path`` specifies the path to the host TPM device's sysfs 3667 entry allowing for cancellation of an ongoing TPM command. 3668 ``cancel-path`` is optional and by default QEMU will search for the 3669 sysfs entry to use. 3670 3671 Some notes about using the host's TPM with the passthrough driver: 3672 3673 The TPM device accessed by the passthrough driver must not be used 3674 by any other application on the host. 3675 3676 Since the host's firmware (BIOS/UEFI) has already initialized the 3677 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3678 the TPM again and may therefore not show a TPM-specific menu that 3679 would otherwise allow the user to configure the TPM, e.g., allow the 3680 user to enable/disable or activate/deactivate the TPM. Further, if 3681 TPM ownership is released from within a VM then the host's TPM will 3682 get disabled and deactivated. To enable and activate the TPM again 3683 afterwards, the host has to be rebooted and the user is required to 3684 enter the firmware's menu to enable and activate the TPM. If the TPM 3685 is left disabled and/or deactivated most TPM commands will fail. 3686 3687 To create a passthrough TPM use the following two options: 3688 3689 :: 3690 3691 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3692 3693 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3694 ``tpmdev=tpm0`` in the device option. 3695 3696``-tpmdev emulator,id=id,chardev=dev`` 3697 (Linux-host only) Enable access to a TPM emulator using Unix domain 3698 socket based chardev backend. 3699 3700 ``chardev`` specifies the unique ID of a character device backend 3701 that provides connection to the software TPM server. 3702 3703 To create a TPM emulator backend device with chardev socket backend: 3704 3705 :: 3706 3707 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3708ERST 3709 3710DEFHEADING() 3711 3712#endif 3713 3714DEFHEADING(Linux/Multiboot boot specific:) 3715SRST 3716When using these options, you can use a given Linux or Multiboot kernel 3717without installing it in the disk image. It can be useful for easier 3718testing of various kernels. 3719 3720 3721ERST 3722 3723DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3724 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3725SRST 3726``-kernel bzImage`` 3727 Use bzImage as kernel image. The kernel can be either a Linux kernel 3728 or in multiboot format. 3729ERST 3730 3731DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3732 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3733SRST 3734``-append cmdline`` 3735 Use cmdline as kernel command line 3736ERST 3737 3738DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3739 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3740SRST 3741``-initrd file`` 3742 Use file as initial ram disk. 3743 3744``-initrd "file1 arg=foo,file2"`` 3745 This syntax is only available with multiboot. 3746 3747 Use file1 and file2 as modules and pass arg=foo as parameter to the 3748 first module. 3749ERST 3750 3751DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3752 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3753SRST 3754``-dtb file`` 3755 Use file as a device tree binary (dtb) image and pass it to the 3756 kernel on boot. 3757ERST 3758 3759DEFHEADING() 3760 3761DEFHEADING(Debug/Expert options:) 3762 3763DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3764 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3765 " Policy for handling deprecated management interfaces\n" 3766 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3767 " Policy for handling unstable management interfaces\n", 3768 QEMU_ARCH_ALL) 3769SRST 3770``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3771 Set policy for handling deprecated management interfaces (experimental): 3772 3773 ``deprecated-input=accept`` (default) 3774 Accept deprecated commands and arguments 3775 ``deprecated-input=reject`` 3776 Reject deprecated commands and arguments 3777 ``deprecated-input=crash`` 3778 Crash on deprecated commands and arguments 3779 ``deprecated-output=accept`` (default) 3780 Emit deprecated command results and events 3781 ``deprecated-output=hide`` 3782 Suppress deprecated command results and events 3783 3784 Limitation: covers only syntactic aspects of QMP. 3785 3786``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3787 Set policy for handling unstable management interfaces (experimental): 3788 3789 ``unstable-input=accept`` (default) 3790 Accept unstable commands and arguments 3791 ``unstable-input=reject`` 3792 Reject unstable commands and arguments 3793 ``unstable-input=crash`` 3794 Crash on unstable commands and arguments 3795 ``unstable-output=accept`` (default) 3796 Emit unstable command results and events 3797 ``unstable-output=hide`` 3798 Suppress unstable command results and events 3799 3800 Limitation: covers only syntactic aspects of QMP. 3801ERST 3802 3803DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3804 "-fw_cfg [name=]<name>,file=<file>\n" 3805 " add named fw_cfg entry with contents from file\n" 3806 "-fw_cfg [name=]<name>,string=<str>\n" 3807 " add named fw_cfg entry with contents from string\n", 3808 QEMU_ARCH_ALL) 3809SRST 3810``-fw_cfg [name=]name,file=file`` 3811 Add named fw\_cfg entry with contents from file file. 3812 3813``-fw_cfg [name=]name,string=str`` 3814 Add named fw\_cfg entry with contents from string str. 3815 3816 The terminating NUL character of the contents of str will not be 3817 included as part of the fw\_cfg item data. To insert contents with 3818 embedded NUL characters, you have to use the file parameter. 3819 3820 The fw\_cfg entries are passed by QEMU through to the guest. 3821 3822 Example: 3823 3824 :: 3825 3826 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3827 3828 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3829 from ./my\_blob.bin. 3830ERST 3831 3832DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3833 "-serial dev redirect the serial port to char device 'dev'\n", 3834 QEMU_ARCH_ALL) 3835SRST 3836``-serial dev`` 3837 Redirect the virtual serial port to host character device dev. The 3838 default device is ``vc`` in graphical mode and ``stdio`` in non 3839 graphical mode. 3840 3841 This option can be used several times to simulate up to 4 serial 3842 ports. 3843 3844 Use ``-serial none`` to disable all serial ports. 3845 3846 Available character devices are: 3847 3848 ``vc[:WxH]`` 3849 Virtual console. Optionally, a width and height can be given in 3850 pixel with 3851 3852 :: 3853 3854 vc:800x600 3855 3856 It is also possible to specify width or height in characters: 3857 3858 :: 3859 3860 vc:80Cx24C 3861 3862 ``pty`` 3863 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3864 3865 ``none`` 3866 No device is allocated. 3867 3868 ``null`` 3869 void device 3870 3871 ``chardev:id`` 3872 Use a named character device defined with the ``-chardev`` 3873 option. 3874 3875 ``/dev/XXX`` 3876 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3877 port parameters are set according to the emulated ones. 3878 3879 ``/dev/parportN`` 3880 [Linux only, parallel port only] Use host parallel port N. 3881 Currently SPP and EPP parallel port features can be used. 3882 3883 ``file:filename`` 3884 Write output to filename. No character can be read. 3885 3886 ``stdio`` 3887 [Unix only] standard input/output 3888 3889 ``pipe:filename`` 3890 name pipe filename 3891 3892 ``COMn`` 3893 [Windows only] Use host serial port n 3894 3895 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3896 This implements UDP Net Console. When remote\_host or src\_ip 3897 are not specified they default to ``0.0.0.0``. When not using a 3898 specified src\_port a random port is automatically chosen. 3899 3900 If you just want a simple readonly console you can use 3901 ``netcat`` or ``nc``, by starting QEMU with: 3902 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3903 QEMU writes something to that port it will appear in the 3904 netconsole session. 3905 3906 If you plan to send characters back via netconsole or you want 3907 to stop and start QEMU a lot of times, you should have QEMU use 3908 the same source port each time by using something like ``-serial 3909 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3910 version of netcat which can listen to a TCP port and send and 3911 receive characters via udp. If you have a patched version of 3912 netcat which activates telnet remote echo and single char 3913 transfer, then you can use the following options to set up a 3914 netcat redirector to allow telnet on port 5555 to access the 3915 QEMU port. 3916 3917 ``QEMU Options:`` 3918 -serial udp::4555@:4556 3919 3920 ``netcat options:`` 3921 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3922 3923 ``telnet options:`` 3924 localhost 5555 3925 3926 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3927 The TCP Net Console has two modes of operation. It can send the 3928 serial I/O to a location or wait for a connection from a 3929 location. By default the TCP Net Console is sent to host at the 3930 port. If you use the ``server=on`` option QEMU will wait for a client 3931 socket application to connect to the port before continuing, 3932 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3933 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3934 option only applies if ``server=no`` is set, if the connection goes 3935 down it will attempt to reconnect at the given interval. If host 3936 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3937 time is accepted. You can use ``telnet=on`` to connect to the 3938 corresponding character device. 3939 3940 ``Example to send tcp console to 192.168.0.2 port 4444`` 3941 -serial tcp:192.168.0.2:4444 3942 3943 ``Example to listen and wait on port 4444 for connection`` 3944 -serial tcp::4444,server=on 3945 3946 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3947 -serial tcp:192.168.0.100:4444,server=on,wait=off 3948 3949 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3950 The telnet protocol is used instead of raw tcp sockets. The 3951 options work the same as if you had specified ``-serial tcp``. 3952 The difference is that the port acts like a telnet server or 3953 client using telnet option negotiation. This will also allow you 3954 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3955 supports sending the break sequence. Typically in unix telnet 3956 you do it with Control-] and then type "send break" followed by 3957 pressing the enter key. 3958 3959 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3960 The WebSocket protocol is used instead of raw tcp socket. The 3961 port acts as a WebSocket server. Client mode is not supported. 3962 3963 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3964 A unix domain socket is used instead of a tcp socket. The option 3965 works the same as if you had specified ``-serial tcp`` except 3966 the unix domain socket path is used for connections. 3967 3968 ``mon:dev_string`` 3969 This is a special option to allow the monitor to be multiplexed 3970 onto another serial port. The monitor is accessed with key 3971 sequence of Control-a and then pressing c. dev\_string should be 3972 any one of the serial devices specified above. An example to 3973 multiplex the monitor onto a telnet server listening on port 3974 4444 would be: 3975 3976 ``-serial mon:telnet::4444,server=on,wait=off`` 3977 3978 When the monitor is multiplexed to stdio in this way, Ctrl+C 3979 will not terminate QEMU any more but will be passed to the guest 3980 instead. 3981 3982 ``braille`` 3983 Braille device. This will use BrlAPI to display the braille 3984 output on a real or fake device. 3985 3986 ``msmouse`` 3987 Three button serial mouse. Configure the guest to use Microsoft 3988 protocol. 3989ERST 3990 3991DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3992 "-parallel dev redirect the parallel port to char device 'dev'\n", 3993 QEMU_ARCH_ALL) 3994SRST 3995``-parallel dev`` 3996 Redirect the virtual parallel port to host device dev (same devices 3997 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3998 to use hardware devices connected on the corresponding host parallel 3999 port. 4000 4001 This option can be used several times to simulate up to 3 parallel 4002 ports. 4003 4004 Use ``-parallel none`` to disable all parallel ports. 4005ERST 4006 4007DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4008 "-monitor dev redirect the monitor to char device 'dev'\n", 4009 QEMU_ARCH_ALL) 4010SRST 4011``-monitor dev`` 4012 Redirect the monitor to host device dev (same devices as the serial 4013 port). The default device is ``vc`` in graphical mode and ``stdio`` 4014 in non graphical mode. Use ``-monitor none`` to disable the default 4015 monitor. 4016ERST 4017DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4018 "-qmp dev like -monitor but opens in 'control' mode\n", 4019 QEMU_ARCH_ALL) 4020SRST 4021``-qmp dev`` 4022 Like -monitor but opens in 'control' mode. 4023ERST 4024DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4025 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4026 QEMU_ARCH_ALL) 4027SRST 4028``-qmp-pretty dev`` 4029 Like -qmp but uses pretty JSON formatting. 4030ERST 4031 4032DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4033 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4034SRST 4035``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4036 Setup monitor on chardev name. ``mode=control`` configures 4037 a QMP monitor (a JSON RPC-style protocol) and it is not the 4038 same as HMP, the human monitor that has a "(qemu)" prompt. 4039 ``pretty`` is only valid when ``mode=control``, 4040 turning on JSON pretty printing to ease 4041 human reading and debugging. 4042ERST 4043 4044DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4045 "-debugcon dev redirect the debug console to char device 'dev'\n", 4046 QEMU_ARCH_ALL) 4047SRST 4048``-debugcon dev`` 4049 Redirect the debug console to host device dev (same devices as the 4050 serial port). The debug console is an I/O port which is typically 4051 port 0xe9; writing to that I/O port sends output to this device. The 4052 default device is ``vc`` in graphical mode and ``stdio`` in non 4053 graphical mode. 4054ERST 4055 4056DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4057 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4058SRST 4059``-pidfile file`` 4060 Store the QEMU process PID in file. It is useful if you launch QEMU 4061 from a script. 4062ERST 4063 4064DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4065 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4066SRST 4067``-singlestep`` 4068 Run the emulation in single step mode. 4069ERST 4070 4071DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4072 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4073 QEMU_ARCH_ALL) 4074SRST 4075``--preconfig`` 4076 Pause QEMU for interactive configuration before the machine is 4077 created, which allows querying and configuring properties that will 4078 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4079 exit the preconfig state and move to the next state (i.e. run guest 4080 if -S isn't used or pause the second time if -S is used). This 4081 option is experimental. 4082ERST 4083 4084DEF("S", 0, QEMU_OPTION_S, \ 4085 "-S freeze CPU at startup (use 'c' to start execution)\n", 4086 QEMU_ARCH_ALL) 4087SRST 4088``-S`` 4089 Do not start CPU at startup (you must type 'c' in the monitor). 4090ERST 4091 4092DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4093 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4094 " run qemu with overcommit hints\n" 4095 " mem-lock=on|off controls memory lock support (default: off)\n" 4096 " cpu-pm=on|off controls cpu power management (default: off)\n", 4097 QEMU_ARCH_ALL) 4098SRST 4099``-overcommit mem-lock=on|off`` 4100 \ 4101``-overcommit cpu-pm=on|off`` 4102 Run qemu with hints about host resource overcommit. The default is 4103 to assume that host overcommits all resources. 4104 4105 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4106 (disabled by default). This works when host memory is not 4107 overcommitted and reduces the worst-case latency for guest. 4108 4109 Guest ability to manage power state of host cpus (increasing latency 4110 for other processes on the same host cpu, but decreasing latency for 4111 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4112 works best when host CPU is not overcommitted. When used, host 4113 estimates of CPU cycle and power utilization will be incorrect, not 4114 taking into account guest idle time. 4115ERST 4116 4117DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4118 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4119 " the guest without waiting for gdb to connect; use -S too\n" 4120 " if you want it to not start execution.)\n", 4121 QEMU_ARCH_ALL) 4122SRST 4123``-gdb dev`` 4124 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4125 in the System Emulation Users Guide). Note that this option does not pause QEMU 4126 execution -- if you want QEMU to not start the guest until you 4127 connect with gdb and issue a ``continue`` command, you will need to 4128 also pass the ``-S`` option to QEMU. 4129 4130 The most usual configuration is to listen on a local TCP socket:: 4131 4132 -gdb tcp::3117 4133 4134 but you can specify other backends; UDP, pseudo TTY, or even stdio 4135 are all reasonable use cases. For example, a stdio connection 4136 allows you to start QEMU from within gdb and establish the 4137 connection via a pipe: 4138 4139 .. parsed-literal:: 4140 4141 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4142ERST 4143 4144DEF("s", 0, QEMU_OPTION_s, \ 4145 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4146 QEMU_ARCH_ALL) 4147SRST 4148``-s`` 4149 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4150 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4151ERST 4152 4153DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4154 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4155 QEMU_ARCH_ALL) 4156SRST 4157``-d item1[,...]`` 4158 Enable logging of specified items. Use '-d help' for a list of log 4159 items. 4160ERST 4161 4162DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4163 "-D logfile output log to logfile (default stderr)\n", 4164 QEMU_ARCH_ALL) 4165SRST 4166``-D logfile`` 4167 Output log in logfile instead of to stderr 4168ERST 4169 4170DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4171 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4172 QEMU_ARCH_ALL) 4173SRST 4174``-dfilter range1[,...]`` 4175 Filter debug output to that relevant to a range of target addresses. 4176 The filter spec can be either start+size, start-size or start..end 4177 where start end and size are the addresses and sizes required. For 4178 example: 4179 4180 :: 4181 4182 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4183 4184 Will dump output for any code in the 0x1000 sized block starting at 4185 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4186 another 0x1000 sized block starting at 0xffffffc00005f000. 4187ERST 4188 4189DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4190 "-seed number seed the pseudo-random number generator\n", 4191 QEMU_ARCH_ALL) 4192SRST 4193``-seed number`` 4194 Force the guest to use a deterministic pseudo-random number 4195 generator, seeded with number. This does not affect crypto routines 4196 within the host. 4197ERST 4198 4199DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4200 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4201 QEMU_ARCH_ALL) 4202SRST 4203``-L path`` 4204 Set the directory for the BIOS, VGA BIOS and keymaps. 4205 4206 To list all the data directories, use ``-L help``. 4207ERST 4208 4209DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4210 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4211SRST 4212``-bios file`` 4213 Set the filename for the BIOS. 4214ERST 4215 4216DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4217 "-enable-kvm enable KVM full virtualization support\n", 4218 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4219 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4220SRST 4221``-enable-kvm`` 4222 Enable KVM full virtualization support. This option is only 4223 available if KVM support is enabled when compiling. 4224ERST 4225 4226DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4227 "-xen-domid id specify xen guest domain id\n", 4228 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4229DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4230 "-xen-attach attach to existing xen domain\n" 4231 " libxl will use this when starting QEMU\n", 4232 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4233DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4234 "-xen-domid-restrict restrict set of available xen operations\n" 4235 " to specified domain id. (Does not affect\n" 4236 " xenpv machine type).\n", 4237 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4238SRST 4239``-xen-domid id`` 4240 Specify xen guest domain id (XEN only). 4241 4242``-xen-attach`` 4243 Attach to existing xen domain. libxl will use this when starting 4244 QEMU (XEN only). Restrict set of available xen operations to 4245 specified domain id (XEN only). 4246ERST 4247 4248DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4249 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4250SRST 4251``-no-reboot`` 4252 Exit instead of rebooting. 4253ERST 4254 4255DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4256 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4257SRST 4258``-no-shutdown`` 4259 Don't exit QEMU on guest shutdown, but instead only stop the 4260 emulation. This allows for instance switching to monitor to commit 4261 changes to the disk image. 4262ERST 4263 4264DEF("action", HAS_ARG, QEMU_OPTION_action, 4265 "-action reboot=reset|shutdown\n" 4266 " action when guest reboots [default=reset]\n" 4267 "-action shutdown=poweroff|pause\n" 4268 " action when guest shuts down [default=poweroff]\n" 4269 "-action panic=pause|shutdown|none\n" 4270 " action when guest panics [default=shutdown]\n" 4271 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4272 " action when watchdog fires [default=reset]\n", 4273 QEMU_ARCH_ALL) 4274SRST 4275``-action event=action`` 4276 The action parameter serves to modify QEMU's default behavior when 4277 certain guest events occur. It provides a generic method for specifying the 4278 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4279 parameters. 4280 4281 Examples: 4282 4283 ``-action panic=none`` 4284 ``-action reboot=shutdown,shutdown=pause`` 4285 ``-watchdog i6300esb -action watchdog=pause`` 4286 4287ERST 4288 4289DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4290 "-loadvm [tag|id]\n" \ 4291 " start right away with a saved state (loadvm in monitor)\n", 4292 QEMU_ARCH_ALL) 4293SRST 4294``-loadvm file`` 4295 Start right away with a saved state (``loadvm`` in monitor) 4296ERST 4297 4298#ifndef _WIN32 4299DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4300 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4301#endif 4302SRST 4303``-daemonize`` 4304 Daemonize the QEMU process after initialization. QEMU will not 4305 detach from standard IO until it is ready to receive connections on 4306 any of its devices. This option is a useful way for external 4307 programs to launch QEMU without having to cope with initialization 4308 race conditions. 4309ERST 4310 4311DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4312 "-option-rom rom load a file, rom, into the option ROM space\n", 4313 QEMU_ARCH_ALL) 4314SRST 4315``-option-rom file`` 4316 Load the contents of file as an option ROM. This option is useful to 4317 load things like EtherBoot. 4318ERST 4319 4320DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4321 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4322 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4323 QEMU_ARCH_ALL) 4324 4325SRST 4326``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4327 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4328 the current UTC or local time, respectively. ``localtime`` is 4329 required for correct date in MS-DOS or Windows. To start at a 4330 specific point in time, provide datetime in the format 4331 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4332 4333 By default the RTC is driven by the host system time. This allows 4334 using of the RTC as accurate reference clock inside the guest, 4335 specifically if the host time is smoothly following an accurate 4336 external reference clock, e.g. via NTP. If you want to isolate the 4337 guest time from the host, you can set ``clock`` to ``rt`` instead, 4338 which provides a host monotonic clock if host support it. To even 4339 prevent the RTC from progressing during suspension, you can set 4340 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4341 recommended especially in icount mode in order to preserve 4342 determinism; however, note that in icount mode the speed of the 4343 virtual clock is variable and can in general differ from the host 4344 clock. 4345 4346 Enable ``driftfix`` (i386 targets only) if you experience time drift 4347 problems, specifically with Windows' ACPI HAL. This option will try 4348 to figure out how many timer interrupts were not processed by the 4349 Windows guest and will re-inject them. 4350ERST 4351 4352DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4353 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4354 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4355 " instruction, enable aligning the host and virtual clocks\n" \ 4356 " or disable real time cpu sleeping, and optionally enable\n" \ 4357 " record-and-replay mode\n", QEMU_ARCH_ALL) 4358SRST 4359``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4360 Enable virtual instruction counter. The virtual cpu will execute one 4361 instruction every 2^N ns of virtual time. If ``auto`` is specified 4362 then the virtual cpu speed will be automatically adjusted to keep 4363 virtual time within a few seconds of real time. 4364 4365 Note that while this option can give deterministic behavior, it does 4366 not provide cycle accurate emulation. Modern CPUs contain 4367 superscalar out of order cores with complex cache hierarchies. The 4368 number of instructions executed often has little or no correlation 4369 with actual performance. 4370 4371 When the virtual cpu is sleeping, the virtual time will advance at 4372 default speed unless ``sleep=on`` is specified. With 4373 ``sleep=on``, the virtual time will jump to the next timer 4374 deadline instantly whenever the virtual cpu goes to sleep mode and 4375 will not advance if no timer is enabled. This behavior gives 4376 deterministic execution times from the guest point of view. 4377 The default if icount is enabled is ``sleep=off``. 4378 ``sleep=on`` cannot be used together with either ``shift=auto`` 4379 or ``align=on``. 4380 4381 ``align=on`` will activate the delay algorithm which will try to 4382 synchronise the host clock and the virtual clock. The goal is to 4383 have a guest running at the real frequency imposed by the shift 4384 option. Whenever the guest clock is behind the host clock and if 4385 ``align=on`` is specified then we print a message to the user to 4386 inform about the delay. Currently this option does not work when 4387 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4388 shift values for which the guest clock runs ahead of the host clock. 4389 Typically this happens when the shift value is high (how high 4390 depends on the host machine). The default if icount is enabled 4391 is ``align=off``. 4392 4393 When the ``rr`` option is specified deterministic record/replay is 4394 enabled. The ``rrfile=`` option must also be provided to 4395 specify the path to the replay log. In record mode data is written 4396 to this file, and in replay mode it is read back. 4397 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4398 name. In record mode, a new VM snapshot with the given name is created 4399 at the start of execution recording. In replay mode this option 4400 specifies the snapshot name used to load the initial VM state. 4401ERST 4402 4403DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4404 "-watchdog model\n" \ 4405 " enable virtual hardware watchdog [default=none]\n", 4406 QEMU_ARCH_ALL) 4407SRST 4408``-watchdog model`` 4409 Create a virtual hardware watchdog device. Once enabled (by a guest 4410 action), the watchdog must be periodically polled by an agent inside 4411 the guest or else the guest will be restarted. Choose a model for 4412 which your guest has drivers. 4413 4414 The model is the model of hardware watchdog to emulate. Use 4415 ``-watchdog help`` to list available hardware models. Only one 4416 watchdog can be enabled for a guest. 4417 4418 The following models may be available: 4419 4420 ``ib700`` 4421 iBASE 700 is a very simple ISA watchdog with a single timer. 4422 4423 ``i6300esb`` 4424 Intel 6300ESB I/O controller hub is a much more featureful 4425 PCI-based dual-timer watchdog. 4426 4427 ``diag288`` 4428 A virtual watchdog for s390x backed by the diagnose 288 4429 hypercall (currently KVM only). 4430ERST 4431 4432DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4433 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4434 " action when watchdog fires [default=reset]\n", 4435 QEMU_ARCH_ALL) 4436SRST 4437``-watchdog-action action`` 4438 The action controls what QEMU will do when the watchdog timer 4439 expires. The default is ``reset`` (forcefully reset the guest). 4440 Other possible actions are: ``shutdown`` (attempt to gracefully 4441 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4442 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4443 guest), ``debug`` (print a debug message and continue), or ``none`` 4444 (do nothing). 4445 4446 Note that the ``shutdown`` action requires that the guest responds 4447 to ACPI signals, which it may not be able to do in the sort of 4448 situations where the watchdog would have expired, and thus 4449 ``-watchdog-action shutdown`` is not recommended for production use. 4450 4451 Examples: 4452 4453 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4454 4455ERST 4456 4457DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4458 "-echr chr set terminal escape character instead of ctrl-a\n", 4459 QEMU_ARCH_ALL) 4460SRST 4461``-echr numeric_ascii_value`` 4462 Change the escape character used for switching to the monitor when 4463 using monitor and serial sharing. The default is ``0x01`` when using 4464 the ``-nographic`` option. ``0x01`` is equal to pressing 4465 ``Control-a``. You can select a different character from the ascii 4466 control keys where 1 through 26 map to Control-a through Control-z. 4467 For instance you could use the either of the following to change the 4468 escape character to Control-t. 4469 4470 ``-echr 0x14``; \ ``-echr 20`` 4471 4472ERST 4473 4474DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4475 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4476 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4477 "-incoming unix:socketpath\n" \ 4478 " prepare for incoming migration, listen on\n" \ 4479 " specified protocol and socket address\n" \ 4480 "-incoming fd:fd\n" \ 4481 "-incoming exec:cmdline\n" \ 4482 " accept incoming migration on given file descriptor\n" \ 4483 " or from given external command\n" \ 4484 "-incoming defer\n" \ 4485 " wait for the URI to be specified via migrate_incoming\n", 4486 QEMU_ARCH_ALL) 4487SRST 4488``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4489 \ 4490``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4491 Prepare for incoming migration, listen on a given tcp port. 4492 4493``-incoming unix:socketpath`` 4494 Prepare for incoming migration, listen on a given unix socket. 4495 4496``-incoming fd:fd`` 4497 Accept incoming migration from a given filedescriptor. 4498 4499``-incoming exec:cmdline`` 4500 Accept incoming migration as an output from specified external 4501 command. 4502 4503``-incoming defer`` 4504 Wait for the URI to be specified via migrate\_incoming. The monitor 4505 can be used to change settings (such as migration parameters) prior 4506 to issuing the migrate\_incoming to allow the migration to begin. 4507ERST 4508 4509DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4510 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4511SRST 4512``-only-migratable`` 4513 Only allow migratable devices. Devices will not be allowed to enter 4514 an unmigratable state. 4515ERST 4516 4517DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4518 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4519SRST 4520``-nodefaults`` 4521 Don't create default devices. Normally, QEMU sets the default 4522 devices like serial port, parallel port, virtual console, monitor 4523 device, VGA adapter, floppy and CD-ROM drive and others. The 4524 ``-nodefaults`` option will disable all those default devices. 4525ERST 4526 4527#ifndef _WIN32 4528DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4529 "-chroot dir chroot to dir just before starting the VM\n", 4530 QEMU_ARCH_ALL) 4531#endif 4532SRST 4533``-chroot dir`` 4534 Immediately before starting guest execution, chroot to the specified 4535 directory. Especially useful in combination with -runas. 4536ERST 4537 4538#ifndef _WIN32 4539DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4540 "-runas user change to user id user just before starting the VM\n" \ 4541 " user can be numeric uid:gid instead\n", 4542 QEMU_ARCH_ALL) 4543#endif 4544SRST 4545``-runas user`` 4546 Immediately before starting guest execution, drop root privileges, 4547 switching to the specified user. 4548ERST 4549 4550DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4551 "-prom-env variable=value\n" 4552 " set OpenBIOS nvram variables\n", 4553 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4554SRST 4555``-prom-env variable=value`` 4556 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4557 4558 :: 4559 4560 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4561 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4562 4563 :: 4564 4565 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4566 -prom-env 'boot-device=hd:2,\yaboot' \ 4567 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4568ERST 4569DEF("semihosting", 0, QEMU_OPTION_semihosting, 4570 "-semihosting semihosting mode\n", 4571 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4572 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4573SRST 4574``-semihosting`` 4575 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4576 4577 Note that this allows guest direct access to the host filesystem, so 4578 should only be used with a trusted guest OS. 4579 4580 See the -semihosting-config option documentation for further 4581 information about the facilities this enables. 4582ERST 4583DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4584 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4585 " semihosting configuration\n", 4586QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4587QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4588SRST 4589``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4590 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4591 only). 4592 4593 Note that this allows guest direct access to the host filesystem, so 4594 should only be used with a trusted guest OS. 4595 4596 On Arm this implements the standard semihosting API, version 2.0. 4597 4598 On M68K this implements the "ColdFire GDB" interface used by 4599 libgloss. 4600 4601 Xtensa semihosting provides basic file IO calls, such as 4602 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4603 linux platform "sim" use this interface. 4604 4605 On RISC-V this implements the standard semihosting API, version 0.2. 4606 4607 ``target=native|gdb|auto`` 4608 Defines where the semihosting calls will be addressed, to QEMU 4609 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4610 means ``gdb`` during debug sessions and ``native`` otherwise. 4611 4612 ``chardev=str1`` 4613 Send the output to a chardev backend output for native or auto 4614 output when not in gdb 4615 4616 ``arg=str1,arg=str2,...`` 4617 Allows the user to pass input arguments, and can be used 4618 multiple times to build up a list. The old-style 4619 ``-kernel``/``-append`` method of passing a command line is 4620 still supported for backward compatibility. If both the 4621 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4622 specified, the former is passed to semihosting as it always 4623 takes precedence. 4624ERST 4625DEF("old-param", 0, QEMU_OPTION_old_param, 4626 "-old-param old param mode\n", QEMU_ARCH_ARM) 4627SRST 4628``-old-param`` 4629 Old param mode (ARM only). 4630ERST 4631 4632DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4633 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4634 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4635 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4636 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4637 " by the kernel, but typically no longer used by modern\n" \ 4638 " C library implementations.\n" \ 4639 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4640 " to elevate privileges using set*uid|gid system calls.\n" \ 4641 " The value 'children' will deny set*uid|gid system calls for\n" \ 4642 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4643 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4644 " blocking *fork and execve\n" \ 4645 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4646 QEMU_ARCH_ALL) 4647SRST 4648``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4649 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4650 filtering and 'off' will disable it. The default is 'off'. 4651 4652 ``obsolete=string`` 4653 Enable Obsolete system calls 4654 4655 ``elevateprivileges=string`` 4656 Disable set\*uid\|gid system calls 4657 4658 ``spawn=string`` 4659 Disable \*fork and execve 4660 4661 ``resourcecontrol=string`` 4662 Disable process affinity and schedular priority 4663ERST 4664 4665DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4666 "-readconfig <file>\n" 4667 " read config file\n", QEMU_ARCH_ALL) 4668SRST 4669``-readconfig file`` 4670 Read device configuration from file. This approach is useful when 4671 you want to spawn QEMU process with many command line options but 4672 you don't want to exceed the command line character limit. 4673ERST 4674 4675DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4676 "-no-user-config\n" 4677 " do not load default user-provided config files at startup\n", 4678 QEMU_ARCH_ALL) 4679SRST 4680``-no-user-config`` 4681 The ``-no-user-config`` option makes QEMU not load any of the 4682 user-provided config files on sysconfdir. 4683ERST 4684 4685DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4686 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4687 " specify tracing options\n", 4688 QEMU_ARCH_ALL) 4689SRST 4690``-trace [[enable=]pattern][,events=file][,file=file]`` 4691 .. include:: ../qemu-option-trace.rst.inc 4692 4693ERST 4694DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4695 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4696 " load a plugin\n", 4697 QEMU_ARCH_ALL) 4698SRST 4699``-plugin file=file[,argname=argvalue]`` 4700 Load a plugin. 4701 4702 ``file=file`` 4703 Load the given plugin from a shared library file. 4704 4705 ``argname=argvalue`` 4706 Argument passed to the plugin. (Can be given multiple times.) 4707ERST 4708 4709HXCOMM Internal use 4710DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4711DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4712 4713DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4714 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4715 " control error message format\n" 4716 " timestamp=on enables timestamps (default: off)\n" 4717 " guest-name=on enables guest name prefix but only if\n" 4718 " -name guest option is set (default: off)\n", 4719 QEMU_ARCH_ALL) 4720SRST 4721``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4722 Control error message format. 4723 4724 ``timestamp=on|off`` 4725 Prefix messages with a timestamp. Default is off. 4726 4727 ``guest-name=on|off`` 4728 Prefix messages with guest name but only if -name guest option is set 4729 otherwise the option is ignored. Default is off. 4730ERST 4731 4732DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4733 "-dump-vmstate <file>\n" 4734 " Output vmstate information in JSON format to file.\n" 4735 " Use the scripts/vmstate-static-checker.py file to\n" 4736 " check for possible regressions in migration code\n" 4737 " by comparing two such vmstate dumps.\n", 4738 QEMU_ARCH_ALL) 4739SRST 4740``-dump-vmstate file`` 4741 Dump json-encoded vmstate information for current machine type to 4742 file in file 4743ERST 4744 4745DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4746 "-enable-sync-profile\n" 4747 " enable synchronization profiling\n", 4748 QEMU_ARCH_ALL) 4749SRST 4750``-enable-sync-profile`` 4751 Enable synchronization profiling. 4752ERST 4753 4754DEFHEADING() 4755 4756DEFHEADING(Generic object creation:) 4757 4758DEF("object", HAS_ARG, QEMU_OPTION_object, 4759 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4760 " create a new object of type TYPENAME setting properties\n" 4761 " in the order they are specified. Note that the 'id'\n" 4762 " property must be set. These objects are placed in the\n" 4763 " '/objects' path.\n", 4764 QEMU_ARCH_ALL) 4765SRST 4766``-object typename[,prop1=value1,...]`` 4767 Create a new object of type typename setting properties in the order 4768 they are specified. Note that the 'id' property must be set. These 4769 objects are placed in the '/objects' path. 4770 4771 ``-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`` 4772 Creates a memory file backend object, which can be used to back 4773 the guest RAM with huge pages. 4774 4775 The ``id`` parameter is a unique ID that will be used to 4776 reference this memory region in other parameters, e.g. ``-numa``, 4777 ``-device nvdimm``, etc. 4778 4779 The ``size`` option provides the size of the memory region, and 4780 accepts common suffixes, e.g. ``500M``. 4781 4782 The ``mem-path`` provides the path to either a shared memory or 4783 huge page filesystem mount. 4784 4785 The ``share`` boolean option determines whether the memory 4786 region is marked as private to QEMU, or shared. The latter 4787 allows a co-operating external process to access the QEMU memory 4788 region. 4789 4790 The ``share`` is also required for pvrdma devices due to 4791 limitations in the RDMA API provided by Linux. 4792 4793 Setting share=on might affect the ability to configure NUMA 4794 bindings for the memory backend under some circumstances, see 4795 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4796 source tree for additional details. 4797 4798 Setting the ``discard-data`` boolean option to on indicates that 4799 file contents can be destroyed when QEMU exits, to avoid 4800 unnecessarily flushing data to the backing file. Note that 4801 ``discard-data`` is only an optimization, and QEMU might not 4802 discard file contents if it aborts unexpectedly or is terminated 4803 using SIGKILL. 4804 4805 The ``merge`` boolean option enables memory merge, also known as 4806 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4807 the pages for memory deduplication. 4808 4809 Setting the ``dump`` boolean option to off excludes the memory 4810 from core dumps. This feature is also known as MADV\_DONTDUMP. 4811 4812 The ``prealloc`` boolean option enables memory preallocation. 4813 4814 The ``host-nodes`` option binds the memory range to a list of 4815 NUMA host nodes. 4816 4817 The ``policy`` option sets the NUMA policy to one of the 4818 following values: 4819 4820 ``default`` 4821 default host policy 4822 4823 ``preferred`` 4824 prefer the given host node list for allocation 4825 4826 ``bind`` 4827 restrict memory allocation to the given host node list 4828 4829 ``interleave`` 4830 interleave memory allocations across the given host node 4831 list 4832 4833 The ``align`` option specifies the base address alignment when 4834 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4835 ``2M``. Some backend store specified by ``mem-path`` requires an 4836 alignment different than the default one used by QEMU, eg the 4837 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4838 such cases, users can specify the required alignment via this 4839 option. 4840 4841 The ``pmem`` option specifies whether the backing file specified 4842 by ``mem-path`` is in host persistent memory that can be 4843 accessed using the SNIA NVM programming model (e.g. Intel 4844 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4845 operations to guarantee the persistence of its own writes to 4846 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4847 migration). Also, we will map the backend-file with MAP\_SYNC 4848 flag, which ensures the file metadata is in sync for 4849 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4850 requires support from both the host kernel (since Linux kernel 4851 4.15) and the filesystem of ``mem-path`` mounted with DAX 4852 option. 4853 4854 The ``readonly`` option specifies whether the backing file is opened 4855 read-only or read-write (default). 4856 4857 ``-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`` 4858 Creates a memory backend object, which can be used to back the 4859 guest RAM. Memory backend objects offer more control than the 4860 ``-m`` option that is traditionally used to define guest RAM. 4861 Please refer to ``memory-backend-file`` for a description of the 4862 options. 4863 4864 ``-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`` 4865 Creates an anonymous memory file backend object, which allows 4866 QEMU to share the memory with an external process (e.g. when 4867 using vhost-user). The memory is allocated with memfd and 4868 optional sealing. (Linux only) 4869 4870 The ``seal`` option creates a sealed-file, that will block 4871 further resizing the memory ('on' by default). 4872 4873 The ``hugetlb`` option specify the file to be created resides in 4874 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4875 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4876 the hugetlb page size on systems that support multiple hugetlb 4877 page sizes (it must be a power of 2 value supported by the 4878 system). 4879 4880 In some versions of Linux, the ``hugetlb`` option is 4881 incompatible with the ``seal`` option (requires at least Linux 4882 4.16). 4883 4884 Please refer to ``memory-backend-file`` for a description of the 4885 other options. 4886 4887 The ``share`` boolean option is on by default with memfd. 4888 4889 ``-object rng-builtin,id=id`` 4890 Creates a random number generator backend which obtains entropy 4891 from QEMU builtin functions. The ``id`` parameter is a unique ID 4892 that will be used to reference this entropy backend from the 4893 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4894 uses this RNG backend. 4895 4896 ``-object rng-random,id=id,filename=/dev/random`` 4897 Creates a random number generator backend which obtains entropy 4898 from a device on the host. The ``id`` parameter is a unique ID 4899 that will be used to reference this entropy backend from the 4900 ``virtio-rng`` device. The ``filename`` parameter specifies 4901 which file to obtain entropy from and if omitted defaults to 4902 ``/dev/urandom``. 4903 4904 ``-object rng-egd,id=id,chardev=chardevid`` 4905 Creates a random number generator backend which obtains entropy 4906 from an external daemon running on the host. The ``id`` 4907 parameter is a unique ID that will be used to reference this 4908 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4909 parameter is the unique ID of a character device backend that 4910 provides the connection to the RNG daemon. 4911 4912 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4913 Creates a TLS anonymous credentials object, which can be used to 4914 provide TLS support on network backends. The ``id`` parameter is 4915 a unique ID which network backends will use to access the 4916 credentials. The ``endpoint`` is either ``server`` or ``client`` 4917 depending on whether the QEMU network backend that uses the 4918 credentials will be acting as a client or as a server. If 4919 ``verify-peer`` is enabled (the default) then once the handshake 4920 is completed, the peer credentials will be verified, though this 4921 is a no-op for anonymous credentials. 4922 4923 The dir parameter tells QEMU where to find the credential files. 4924 For server endpoints, this directory may contain a file 4925 dh-params.pem providing diffie-hellman parameters to use for the 4926 TLS server. If the file is missing, QEMU will generate a set of 4927 DH parameters at startup. This is a computationally expensive 4928 operation that consumes random pool entropy, so it is 4929 recommended that a persistent set of parameters be generated 4930 upfront and saved. 4931 4932 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4933 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4934 can be used to provide TLS support on network backends. The 4935 ``id`` parameter is a unique ID which network backends will use 4936 to access the credentials. The ``endpoint`` is either ``server`` 4937 or ``client`` depending on whether the QEMU network backend that 4938 uses the credentials will be acting as a client or as a server. 4939 For clients only, ``username`` is the username which will be 4940 sent to the server. If omitted it defaults to "qemu". 4941 4942 The dir parameter tells QEMU where to find the keys file. It is 4943 called "dir/keys.psk" and contains "username:key" pairs. This 4944 file can most easily be created using the GnuTLS ``psktool`` 4945 program. 4946 4947 For server endpoints, dir may also contain a file dh-params.pem 4948 providing diffie-hellman parameters to use for the TLS server. 4949 If the file is missing, QEMU will generate a set of DH 4950 parameters at startup. This is a computationally expensive 4951 operation that consumes random pool entropy, so it is 4952 recommended that a persistent set of parameters be generated up 4953 front and saved. 4954 4955 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4956 Creates a TLS anonymous credentials object, which can be used to 4957 provide TLS support on network backends. The ``id`` parameter is 4958 a unique ID which network backends will use to access the 4959 credentials. The ``endpoint`` is either ``server`` or ``client`` 4960 depending on whether the QEMU network backend that uses the 4961 credentials will be acting as a client or as a server. If 4962 ``verify-peer`` is enabled (the default) then once the handshake 4963 is completed, the peer credentials will be verified. With x509 4964 certificates, this implies that the clients must be provided 4965 with valid client certificates too. 4966 4967 The dir parameter tells QEMU where to find the credential files. 4968 For server endpoints, this directory may contain a file 4969 dh-params.pem providing diffie-hellman parameters to use for the 4970 TLS server. If the file is missing, QEMU will generate a set of 4971 DH parameters at startup. This is a computationally expensive 4972 operation that consumes random pool entropy, so it is 4973 recommended that a persistent set of parameters be generated 4974 upfront and saved. 4975 4976 For x509 certificate credentials the directory will contain 4977 further files providing the x509 certificates. The certificates 4978 must be stored in PEM format, in filenames ca-cert.pem, 4979 ca-crl.pem (optional), server-cert.pem (only servers), 4980 server-key.pem (only servers), client-cert.pem (only clients), 4981 and client-key.pem (only clients). 4982 4983 For the server-key.pem and client-key.pem files which contain 4984 sensitive private keys, it is possible to use an encrypted 4985 version by providing the passwordid parameter. This provides the 4986 ID of a previously created ``secret`` object containing the 4987 password for decryption. 4988 4989 The priority parameter allows to override the global default 4990 priority used by gnutls. This can be useful if the system 4991 administrator needs to use a weaker set of crypto priorities for 4992 QEMU without potentially forcing the weakness onto all 4993 applications. Or conversely if one wants wants a stronger 4994 default for QEMU than for all other applications, they can do 4995 this through this parameter. Its format is a gnutls priority 4996 string as described at 4997 https://gnutls.org/manual/html_node/Priority-Strings.html. 4998 4999 ``-object tls-cipher-suites,id=id,priority=priority`` 5000 Creates a TLS cipher suites object, which can be used to control 5001 the TLS cipher/protocol algorithms that applications are permitted 5002 to use. 5003 5004 The ``id`` parameter is a unique ID which frontends will use to 5005 access the ordered list of permitted TLS cipher suites from the 5006 host. 5007 5008 The ``priority`` parameter allows to override the global default 5009 priority used by gnutls. This can be useful if the system 5010 administrator needs to use a weaker set of crypto priorities for 5011 QEMU without potentially forcing the weakness onto all 5012 applications. Or conversely if one wants wants a stronger 5013 default for QEMU than for all other applications, they can do 5014 this through this parameter. Its format is a gnutls priority 5015 string as described at 5016 https://gnutls.org/manual/html_node/Priority-Strings.html. 5017 5018 An example of use of this object is to control UEFI HTTPS Boot. 5019 The tls-cipher-suites object exposes the ordered list of permitted 5020 TLS cipher suites from the host side to the guest firmware, via 5021 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5022 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5023 guest-side TLS. 5024 5025 In the following example, the priority at which the host-side policy 5026 is retrieved is given by the ``priority`` property. 5027 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5028 refer to /etc/crypto-policies/back-ends/gnutls.config. 5029 5030 .. parsed-literal:: 5031 5032 # |qemu_system| \\ 5033 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5034 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5035 5036 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5037 Interval t can't be 0, this filter batches the packet delivery: 5038 all packets arriving in a given interval on netdev netdevid are 5039 delayed until the end of the interval. Interval is in 5040 microseconds. ``status`` is optional that indicate whether the 5041 netfilter is on (enabled) or off (disabled), the default status 5042 for netfilter will be 'on'. 5043 5044 queue all\|rx\|tx is an option that can be applied to any 5045 netfilter. 5046 5047 ``all``: the filter is attached both to the receive and the 5048 transmit queue of the netdev (default). 5049 5050 ``rx``: the filter is attached to the receive queue of the 5051 netdev, where it will receive packets sent to the netdev. 5052 5053 ``tx``: the filter is attached to the transmit queue of the 5054 netdev, where it will receive packets sent by the netdev. 5055 5056 position head\|tail\|id=<id> is an option to specify where the 5057 filter should be inserted in the filter list. It can be applied 5058 to any netfilter. 5059 5060 ``head``: the filter is inserted at the head of the filter list, 5061 before any existing filters. 5062 5063 ``tail``: the filter is inserted at the tail of the filter list, 5064 behind any existing filters (default). 5065 5066 ``id=<id>``: the filter is inserted before or behind the filter 5067 specified by <id>, see the insert option below. 5068 5069 insert behind\|before is an option to specify where to insert 5070 the new filter relative to the one specified with 5071 position=id=<id>. It can be applied to any netfilter. 5072 5073 ``before``: insert before the specified filter. 5074 5075 ``behind``: insert behind the specified filter (default). 5076 5077 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5078 filter-mirror on netdev netdevid,mirror net packet to 5079 chardevchardevid, if it has the vnet\_hdr\_support flag, 5080 filter-mirror will mirror packet with vnet\_hdr\_len. 5081 5082 ``-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]`` 5083 filter-redirector on netdev netdevid,redirect filter's net 5084 packet to chardev chardevid,and redirect indev's packet to 5085 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5086 will redirect packet with vnet\_hdr\_len. Create a 5087 filter-redirector we need to differ outdev id from indev id, id 5088 can not be the same. we can just use indev or outdev, but at 5089 least one of indev or outdev need to be specified. 5090 5091 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5092 Filter-rewriter is a part of COLO project.It will rewrite tcp 5093 packet to secondary from primary to keep secondary tcp 5094 connection,and rewrite tcp packet to primary from secondary make 5095 tcp packet can be handled by client.if it has the 5096 vnet\_hdr\_support flag, we can parse packet with vnet header. 5097 5098 usage: colo secondary: -object 5099 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5100 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5101 filter-rewriter,id=rew0,netdev=hn0,queue=all 5102 5103 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5104 Dump the network traffic on netdev dev to the file specified by 5105 filename. At most len bytes (64k by default) per packet are 5106 stored. The file format is libpcap, so it can be analyzed with 5107 tools such as tcpdump or Wireshark. 5108 5109 ``-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}]`` 5110 Colo-compare gets packet from primary\_in chardevid and 5111 secondary\_in, then compare whether the payload of primary packet 5112 and secondary packet are the same. If same, it will output 5113 primary packet to out\_dev, else it will notify COLO-framework to do 5114 checkpoint and send primary packet to out\_dev. In order to 5115 improve efficiency, we need to put the task of comparison in 5116 another iothread. If it has the vnet\_hdr\_support flag, 5117 colo compare will send/recv packet with vnet\_hdr\_len. 5118 The compare\_timeout=@var{ms} determines the maximum time of the 5119 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5120 is to set the period of scanning expired primary node network packets. 5121 The max\_queue\_size=@var{size} is to set the max compare queue 5122 size depend on user environment. 5123 If user want to use Xen COLO, need to add the notify\_dev to 5124 notify Xen colo-frame to do checkpoint. 5125 5126 COLO-compare must be used with the help of filter-mirror, 5127 filter-redirector and filter-rewriter. 5128 5129 :: 5130 5131 KVM COLO 5132 5133 primary: 5134 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5135 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5136 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5137 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5138 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5139 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5140 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5141 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5142 -object iothread,id=iothread1 5143 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5144 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5145 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5146 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5147 5148 secondary: 5149 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5150 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5151 -chardev socket,id=red0,host=3.3.3.3,port=9003 5152 -chardev socket,id=red1,host=3.3.3.3,port=9004 5153 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5154 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5155 5156 5157 Xen COLO 5158 5159 primary: 5160 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5161 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5162 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5163 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5164 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5165 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5166 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5167 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5168 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5169 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5170 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5171 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5172 -object iothread,id=iothread1 5173 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5174 5175 secondary: 5176 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5177 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5178 -chardev socket,id=red0,host=3.3.3.3,port=9003 5179 -chardev socket,id=red1,host=3.3.3.3,port=9004 5180 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5181 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5182 5183 If you want to know the detail of above command line, you can 5184 read the colo-compare git log. 5185 5186 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5187 Creates a cryptodev backend which executes crypto opreation from 5188 the QEMU cipher APIS. The id parameter is a unique ID that will 5189 be used to reference this cryptodev backend from the 5190 ``virtio-crypto`` device. The queues parameter is optional, 5191 which specify the queue number of cryptodev backend, the default 5192 of queues is 1. 5193 5194 .. parsed-literal:: 5195 5196 # |qemu_system| \\ 5197 [...] \\ 5198 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5199 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5200 [...] 5201 5202 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5203 Creates a vhost-user cryptodev backend, backed by a chardev 5204 chardevid. The id parameter is a unique ID that will be used to 5205 reference this cryptodev backend from the ``virtio-crypto`` 5206 device. The chardev should be a unix domain socket backed one. 5207 The vhost-user uses a specifically defined protocol to pass 5208 vhost ioctl replacement messages to an application on the other 5209 end of the socket. The queues parameter is optional, which 5210 specify the queue number of cryptodev backend for multiqueue 5211 vhost-user, the default of queues is 1. 5212 5213 .. parsed-literal:: 5214 5215 # |qemu_system| \\ 5216 [...] \\ 5217 -chardev socket,id=chardev0,path=/path/to/socket \\ 5218 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5219 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5220 [...] 5221 5222 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5223 \ 5224 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5225 Defines a secret to store a password, encryption key, or some 5226 other sensitive data. The sensitive data can either be passed 5227 directly via the data parameter, or indirectly via the file 5228 parameter. Using the data parameter is insecure unless the 5229 sensitive data is encrypted. 5230 5231 The sensitive data can be provided in raw format (the default), 5232 or base64. When encoded as JSON, the raw format only supports 5233 valid UTF-8 characters, so base64 is recommended for sending 5234 binary data. QEMU will convert from which ever format is 5235 provided to the format it needs internally. eg, an RBD password 5236 can be provided in raw format, even though it will be base64 5237 encoded when passed onto the RBD sever. 5238 5239 For added protection, it is possible to encrypt the data 5240 associated with a secret using the AES-256-CBC cipher. Use of 5241 encryption is indicated by providing the keyid and iv 5242 parameters. The keyid parameter provides the ID of a previously 5243 defined secret that contains the AES-256 decryption key. This 5244 key should be 32-bytes long and be base64 encoded. The iv 5245 parameter provides the random initialization vector used for 5246 encryption of this particular secret and should be a base64 5247 encrypted string of the 16-byte IV. 5248 5249 The simplest (insecure) usage is to provide the secret inline 5250 5251 .. parsed-literal:: 5252 5253 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5254 5255 The simplest secure usage is to provide the secret via a file 5256 5257 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5258 secret,id=sec0,file=mypasswd.txt,format=raw 5259 5260 For greater security, AES-256-CBC should be used. To illustrate 5261 usage, consider the openssl command line tool which can encrypt 5262 the data. Note that when encrypting, the plaintext must be 5263 padded to the cipher block size (32 bytes) using the standard 5264 PKCS#5/6 compatible padding algorithm. 5265 5266 First a master key needs to be created in base64 encoding: 5267 5268 :: 5269 5270 # openssl rand -base64 32 > key.b64 5271 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5272 5273 Each secret to be encrypted needs to have a random 5274 initialization vector generated. These do not need to be kept 5275 secret 5276 5277 :: 5278 5279 # openssl rand -base64 16 > iv.b64 5280 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5281 5282 The secret to be defined can now be encrypted, in this case 5283 we're telling openssl to base64 encode the result, but it could 5284 be left as raw bytes if desired. 5285 5286 :: 5287 5288 # SECRET=$(printf "letmein" | 5289 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5290 5291 When launching QEMU, create a master secret pointing to 5292 ``key.b64`` and specify that to be used to decrypt the user 5293 password. Pass the contents of ``iv.b64`` to the second secret 5294 5295 .. parsed-literal:: 5296 5297 # |qemu_system| \\ 5298 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5299 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5300 data=$SECRET,iv=$(<iv.b64) 5301 5302 ``-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]`` 5303 Create a Secure Encrypted Virtualization (SEV) guest object, 5304 which can be used to provide the guest memory encryption support 5305 on AMD processors. 5306 5307 When memory encryption is enabled, one of the physical address 5308 bit (aka the C-bit) is utilized to mark if a memory page is 5309 protected. The ``cbitpos`` is used to provide the C-bit 5310 position. The C-bit position is Host family dependent hence user 5311 must provide this value. On EPYC, the value should be 47. 5312 5313 When memory encryption is enabled, we loose certain bits in 5314 physical address space. The ``reduced-phys-bits`` is used to 5315 provide the number of bits we loose in physical address space. 5316 Similar to C-bit, the value is Host family dependent. On EPYC, 5317 the value should be 5. 5318 5319 The ``sev-device`` provides the device file to use for 5320 communicating with the SEV firmware running inside AMD Secure 5321 Processor. The default device is '/dev/sev'. If hardware 5322 supports memory encryption then /dev/sev devices are created by 5323 CCP driver. 5324 5325 The ``policy`` provides the guest policy to be enforced by the 5326 SEV firmware and restrict what configuration and operational 5327 commands can be performed on this guest by the hypervisor. The 5328 policy should be provided by the guest owner and is bound to the 5329 guest and cannot be changed throughout the lifetime of the 5330 guest. The default is 0. 5331 5332 If guest ``policy`` allows sharing the key with another SEV 5333 guest then ``handle`` can be use to provide handle of the guest 5334 from which to share the key. 5335 5336 The ``dh-cert-file`` and ``session-file`` provides the guest 5337 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5338 and session parameters are used for establishing a cryptographic 5339 session with the guest owner to negotiate keys used for 5340 attestation. The file must be encoded in base64. 5341 5342 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5343 cmdline to a designated guest firmware page for measured Linux 5344 boot with -kernel. The default is off. (Since 6.2) 5345 5346 e.g to launch a SEV guest 5347 5348 .. parsed-literal:: 5349 5350 # |qemu_system_x86| \\ 5351 ...... \\ 5352 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5353 -machine ...,memory-encryption=sev0 \\ 5354 ..... 5355 5356 ``-object authz-simple,id=id,identity=string`` 5357 Create an authorization object that will control access to 5358 network services. 5359 5360 The ``identity`` parameter is identifies the user and its format 5361 depends on the network service that authorization object is 5362 associated with. For authorizing based on TLS x509 certificates, 5363 the identity must be the x509 distinguished name. Note that care 5364 must be taken to escape any commas in the distinguished name. 5365 5366 An example authorization object to validate a x509 distinguished 5367 name would look like: 5368 5369 .. parsed-literal:: 5370 5371 # |qemu_system| \\ 5372 ... \\ 5373 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5374 ... 5375 5376 Note the use of quotes due to the x509 distinguished name 5377 containing whitespace, and escaping of ','. 5378 5379 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5380 Create an authorization object that will control access to 5381 network services. 5382 5383 The ``filename`` parameter is the fully qualified path to a file 5384 containing the access control list rules in JSON format. 5385 5386 An example set of rules that match against SASL usernames might 5387 look like: 5388 5389 :: 5390 5391 { 5392 "rules": [ 5393 { "match": "fred", "policy": "allow", "format": "exact" }, 5394 { "match": "bob", "policy": "allow", "format": "exact" }, 5395 { "match": "danb", "policy": "deny", "format": "glob" }, 5396 { "match": "dan*", "policy": "allow", "format": "exact" }, 5397 ], 5398 "policy": "deny" 5399 } 5400 5401 When checking access the object will iterate over all the rules 5402 and the first rule to match will have its ``policy`` value 5403 returned as the result. If no rules match, then the default 5404 ``policy`` value is returned. 5405 5406 The rules can either be an exact string match, or they can use 5407 the simple UNIX glob pattern matching to allow wildcards to be 5408 used. 5409 5410 If ``refresh`` is set to true the file will be monitored and 5411 automatically reloaded whenever its content changes. 5412 5413 As with the ``authz-simple`` object, the format of the identity 5414 strings being matched depends on the network service, but is 5415 usually a TLS x509 distinguished name, or a SASL username. 5416 5417 An example authorization object to validate a SASL username 5418 would look like: 5419 5420 .. parsed-literal:: 5421 5422 # |qemu_system| \\ 5423 ... \\ 5424 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5425 ... 5426 5427 ``-object authz-pam,id=id,service=string`` 5428 Create an authorization object that will control access to 5429 network services. 5430 5431 The ``service`` parameter provides the name of a PAM service to 5432 use for authorization. It requires that a file 5433 ``/etc/pam.d/service`` exist to provide the configuration for 5434 the ``account`` subsystem. 5435 5436 An example authorization object to validate a TLS x509 5437 distinguished name would look like: 5438 5439 .. parsed-literal:: 5440 5441 # |qemu_system| \\ 5442 ... \\ 5443 -object authz-pam,id=auth0,service=qemu-vnc \\ 5444 ... 5445 5446 There would then be a corresponding config file for PAM at 5447 ``/etc/pam.d/qemu-vnc`` that contains: 5448 5449 :: 5450 5451 account requisite pam_listfile.so item=user sense=allow \ 5452 file=/etc/qemu/vnc.allow 5453 5454 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5455 of x509 distingished names that are permitted access 5456 5457 :: 5458 5459 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5460 5461 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5462 Creates a dedicated event loop thread that devices can be 5463 assigned to. This is known as an IOThread. By default device 5464 emulation happens in vCPU threads or the main event loop thread. 5465 This can become a scalability bottleneck. IOThreads allow device 5466 emulation and I/O to run on other host CPUs. 5467 5468 The ``id`` parameter is a unique ID that will be used to 5469 reference this IOThread from ``-device ...,iothread=id``. 5470 Multiple devices can be assigned to an IOThread. Note that not 5471 all devices support an ``iothread`` parameter. 5472 5473 The ``query-iothreads`` QMP command lists IOThreads and reports 5474 their thread IDs so that the user can configure host CPU 5475 pinning/affinity. 5476 5477 IOThreads use an adaptive polling algorithm to reduce event loop 5478 latency. Instead of entering a blocking system call to monitor 5479 file descriptors and then pay the cost of being woken up when an 5480 event occurs, the polling algorithm spins waiting for events for 5481 a short time. The algorithm's default parameters are suitable 5482 for many cases but can be adjusted based on knowledge of the 5483 workload and/or host device latency. 5484 5485 The ``poll-max-ns`` parameter is the maximum number of 5486 nanoseconds to busy wait for events. Polling can be disabled by 5487 setting this value to 0. 5488 5489 The ``poll-grow`` parameter is the multiplier used to increase 5490 the polling time when the algorithm detects it is missing events 5491 due to not polling long enough. 5492 5493 The ``poll-shrink`` parameter is the divisor used to decrease 5494 the polling time when the algorithm detects it is spending too 5495 long polling without encountering events. 5496 5497 The ``aio-max-batch`` parameter is the maximum number of requests 5498 in a batch for the AIO engine, 0 means that the engine will use 5499 its default. 5500 5501 The IOThread parameters can be modified at run-time using the 5502 ``qom-set`` command (where ``iothread1`` is the IOThread's 5503 ``id``): 5504 5505 :: 5506 5507 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5508ERST 5509 5510 5511HXCOMM This is the last statement. Insert new options before this line! 5512 5513#undef DEF 5514#undef DEFHEADING 5515#undef ARCHHEADING 5516