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