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