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 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 108 -machine memory-backend=pc.ram 109 -m 512M 110 111 Migration compatibility note: 112 a) as backend id one shall use value of 'default-ram-id', advertised by 113 machine type (available via ``query-machines`` QMP command), if migration 114 to/from old QEMU (<5.0) is expected. 115 b) for machine types 4.0 and older, user shall 116 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 117 if migration to/from old QEMU (<5.0) is expected. 118 For example: 119 :: 120 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 121 -machine memory-backend=pc.ram 122 -m 512M 123ERST 124 125HXCOMM Deprecated by -machine 126DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL) 127 128DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 129 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 130SRST 131``-cpu model`` 132 Select CPU model (``-cpu help`` for list and additional feature 133 selection) 134ERST 135 136DEF("accel", HAS_ARG, QEMU_OPTION_accel, 137 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 138 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 139 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 140 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 141 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 142 " split-wx=on|off (enable TCG split w^x mapping)\n" 143 " tb-size=n (TCG translation block cache size)\n" 144 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 145 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 146SRST 147``-accel name[,prop=value[,...]]`` 148 This is used to enable an accelerator. Depending on the target 149 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 150 default, tcg is used. If there is more than one accelerator 151 specified, the next one is used if the previous one fails to 152 initialize. 153 154 ``igd-passthru=on|off`` 155 When Xen is in use, this option controls whether Intel 156 integrated graphics devices can be passed through to the guest 157 (default=off) 158 159 ``kernel-irqchip=on|off|split`` 160 Controls KVM in-kernel irqchip support. The default is full 161 acceleration of the interrupt controllers. On x86, split irqchip 162 reduces the kernel attack surface, at a performance cost for 163 non-MSI interrupts. Disabling the in-kernel irqchip completely 164 is not recommended except for debugging purposes. 165 166 ``kvm-shadow-mem=size`` 167 Defines the size of the KVM shadow MMU. 168 169 ``split-wx=on|off`` 170 Controls the use of split w^x mapping for the TCG code generation 171 buffer. Some operating systems require this to be enabled, and in 172 such a case this will default on. On other operating systems, this 173 will default off, but one may enable this for testing or debugging. 174 175 ``tb-size=n`` 176 Controls the size (in MiB) of the TCG translation block cache. 177 178 ``thread=single|multi`` 179 Controls number of TCG threads. When the TCG is multi-threaded 180 there will be one thread per vCPU therefore taking advantage of 181 additional host cores. The default is to enable multi-threading 182 where both the back-end and front-ends support it and no 183 incompatible TCG features have been enabled (e.g. 184 icount/replay). 185 186 ``dirty-ring-size=n`` 187 When the KVM accelerator is used, it controls the size of the per-vCPU 188 dirty page ring buffer (number of entries for each vCPU). It should 189 be a value that is power of two, and it should be 1024 or bigger (but 190 still less than the maximum value that the kernel supports). 4096 191 could be a good initial value if you have no idea which is the best. 192 Set this value to 0 to disable the feature. By default, this feature 193 is disabled (dirty-ring-size=0). When enabled, KVM will instead 194 record dirty pages in a bitmap. 195 196ERST 197 198DEF("smp", HAS_ARG, QEMU_OPTION_smp, 199 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 200 " set the number of CPUs to 'n' [default=1]\n" 201 " maxcpus= maximum number of total cpus, including\n" 202 " offline CPUs for hotplug, etc\n" 203 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 204 " threads= number of threads on one CPU core\n" 205 " dies= number of CPU dies on one socket (for PC only)\n" 206 " sockets= number of discrete sockets in the system\n", 207 QEMU_ARCH_ALL) 208SRST 209``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]`` 210 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs 211 are supported. On Sparc32 target, Linux limits the number of usable 212 CPUs to 4. For the PC target, the number of cores per die, the 213 number of threads per cores, the number of dies per packages and the 214 total number of sockets can be specified. Missing values will be 215 computed. If any on the three values is given, the total number of 216 CPUs n can be omitted. maxcpus specifies the maximum number of 217 hotpluggable CPUs. 218ERST 219 220DEF("numa", HAS_ARG, QEMU_OPTION_numa, 221 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 222 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 223 "-numa dist,src=source,dst=destination,val=distance\n" 224 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 225 "-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" 226 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 227 QEMU_ARCH_ALL) 228SRST 229``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 230 \ 231``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 232 \ 233``-numa dist,src=source,dst=destination,val=distance`` 234 \ 235``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 236 \ 237``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 238 \ 239``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 240 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 241 distance from a source node to a destination node. Set the ACPI 242 Heterogeneous Memory Attributes for the given nodes. 243 244 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 245 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 246 contiguous range of CPU indexes (or a single VCPU if lastcpu is 247 omitted). A non-contiguous set of VCPUs can be represented by 248 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 249 omitted on all nodes, VCPUs are automatically split between them. 250 251 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 252 NUMA node: 253 254 :: 255 256 -numa node,cpus=0-2,cpus=5 257 258 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 259 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 260 assign CPU objects to a node using topology layout properties of 261 CPU. The set of properties is machine specific, and depends on used 262 machine type/'\ ``smp``\ ' options. It could be queried with 263 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 264 property specifies node to which CPU object will be assigned, it's 265 required for node to be declared with '\ ``node``\ ' option before 266 it's used with '\ ``cpu``\ ' option. 267 268 For example: 269 270 :: 271 272 -M pc \ 273 -smp 1,sockets=2,maxcpus=2 \ 274 -numa node,nodeid=0 -numa node,nodeid=1 \ 275 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 276 277 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 278 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 279 a given memory backend device to a node. If '\ ``mem``\ ' and 280 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 281 282 283 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 284 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 285 use it. 286 287 '\ ``initiator``\ ' is an additional option that points to an 288 initiator NUMA node that has best performance (the lowest latency or 289 largest bandwidth) to this NUMA node. Note that this option can be 290 set only when the machine property 'hmat' is set to 'on'. 291 292 Following example creates a machine with 2 NUMA nodes, node 0 has 293 CPU. node 1 has only memory, and its initiator is node 0. Note that 294 because node 0 has CPU, by default the initiator of node 0 is itself 295 and must be itself. 296 297 :: 298 299 -machine hmat=on \ 300 -m 2G,slots=2,maxmem=4G \ 301 -object memory-backend-ram,size=1G,id=m0 \ 302 -object memory-backend-ram,size=1G,id=m1 \ 303 -numa node,nodeid=0,memdev=m0 \ 304 -numa node,nodeid=1,memdev=m1,initiator=0 \ 305 -smp 2,sockets=2,maxcpus=2 \ 306 -numa cpu,node-id=0,socket-id=0 \ 307 -numa cpu,node-id=0,socket-id=1 308 309 source and destination are NUMA node IDs. distance is the NUMA 310 distance from source to destination. The distance from a node to 311 itself is always 10. If any pair of nodes is given a distance, then 312 all pairs must be given distances. Although, when distances are only 313 given in one direction for each pair of nodes, then the distances in 314 the opposite directions are assumed to be the same. If, however, an 315 asymmetrical pair of distances is given for even one node pair, then 316 all node pairs must be provided distance values for both directions, 317 even when they are symmetrical. When a node is unreachable from 318 another node, set the pair's distance to 255. 319 320 Note that the -``numa`` option doesn't allocate any of the specified 321 resources, it just assigns existing resources to NUMA nodes. This 322 means that one still has to use the ``-m``, ``-smp`` options to 323 allocate RAM and VCPUs respectively. 324 325 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 326 Information between initiator and target NUMA nodes in ACPI 327 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 328 create memory requests, usually it has one or more processors. 329 Target NUMA node contains addressable memory. 330 331 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 332 the memory hierarchy of the target NUMA node: if hierarchy is 333 'memory', the structure represents the memory performance; if 334 hierarchy is 'first-level\|second-level\|third-level', this 335 structure represents aggregated performance of memory side caches 336 for each domain. type of 'data-type' is type of data represented by 337 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 338 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 339 the target memory; if 'hierarchy' is 340 'first-level\|second-level\|third-level', 'data-type' is 341 'access\|read\|write' hit latency or 'access\|read\|write' hit 342 bandwidth of the target memory side cache. 343 344 lat is latency value in nanoseconds. bw is bandwidth value, the 345 possible value and units are NUM[M\|G\|T], mean that the bandwidth 346 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 347 used suffix). Note that if latency or bandwidth value is 0, means 348 the corresponding latency or bandwidth information is not provided. 349 350 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 351 belongs. size is the size of memory side cache in bytes. level is 352 the cache level described in this structure, note that the cache 353 level 0 should not be used with '\ ``hmat-cache``\ ' option. 354 associativity is the cache associativity, the possible value is 355 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 356 is the write policy. line is the cache Line size in bytes. 357 358 For example, the following options describe 2 NUMA nodes. Node 0 has 359 2 cpus and a ram, node 1 has only a ram. The processors in node 0 360 access memory in node 0 with access-latency 5 nanoseconds, 361 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 362 memory in NUMA node 1 with access-latency 10 nanoseconds, 363 access-bandwidth is 100 MB/s. And for memory side cache information, 364 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 365 policy is write-back, the cache Line size is 8 bytes: 366 367 :: 368 369 -machine hmat=on \ 370 -m 2G \ 371 -object memory-backend-ram,size=1G,id=m0 \ 372 -object memory-backend-ram,size=1G,id=m1 \ 373 -smp 2 \ 374 -numa node,nodeid=0,memdev=m0 \ 375 -numa node,nodeid=1,memdev=m1,initiator=0 \ 376 -numa cpu,node-id=0,socket-id=0 \ 377 -numa cpu,node-id=0,socket-id=1 \ 378 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 379 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 380 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 381 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 382 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 383 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 384ERST 385 386DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 387 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 388 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 389SRST 390``-add-fd fd=fd,set=set[,opaque=opaque]`` 391 Add a file descriptor to an fd set. Valid options are: 392 393 ``fd=fd`` 394 This option defines the file descriptor of which a duplicate is 395 added to fd set. The file descriptor cannot be stdin, stdout, or 396 stderr. 397 398 ``set=set`` 399 This option defines the ID of the fd set to add the file 400 descriptor to. 401 402 ``opaque=opaque`` 403 This option defines a free-form string that can be used to 404 describe fd. 405 406 You can open an image using pre-opened file descriptors from an fd 407 set: 408 409 .. parsed-literal:: 410 411 |qemu_system| \\ 412 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 413 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 414 -drive file=/dev/fdset/2,index=0,media=disk 415ERST 416 417DEF("set", HAS_ARG, QEMU_OPTION_set, 418 "-set group.id.arg=value\n" 419 " set <arg> parameter for item <id> of type <group>\n" 420 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 421SRST 422``-set group.id.arg=value`` 423 Set parameter arg for item id of type group 424ERST 425 426DEF("global", HAS_ARG, QEMU_OPTION_global, 427 "-global driver.property=value\n" 428 "-global driver=driver,property=property,value=value\n" 429 " set a global default for a driver property\n", 430 QEMU_ARCH_ALL) 431SRST 432``-global driver.prop=value`` 433 \ 434``-global driver=driver,property=property,value=value`` 435 Set default value of driver's property prop to value, e.g.: 436 437 .. parsed-literal:: 438 439 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 440 441 In particular, you can use this to set driver properties for devices 442 which are created automatically by the machine model. To create a 443 device which is not created automatically and set properties on it, 444 use -``device``. 445 446 -global driver.prop=value is shorthand for -global 447 driver=driver,property=prop,value=value. The longhand syntax works 448 even when driver contains a dot. 449ERST 450 451DEF("boot", HAS_ARG, QEMU_OPTION_boot, 452 "-boot [order=drives][,once=drives][,menu=on|off]\n" 453 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 454 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 455 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 456 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 457 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 458 QEMU_ARCH_ALL) 459SRST 460``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 461 Specify boot order drives as a string of drive letters. Valid drive 462 letters depend on the target architecture. The x86 PC uses: a, b 463 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 464 (Etherboot from network adapter 1-4), hard disk boot is the default. 465 To apply a particular boot order only on the first startup, specify 466 it via ``once``. Note that the ``order`` or ``once`` parameter 467 should not be used together with the ``bootindex`` property of 468 devices, since the firmware implementations normally do not support 469 both at the same time. 470 471 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 472 as firmware/BIOS supports them. The default is non-interactive boot. 473 474 A splash picture could be passed to bios, enabling user to show it 475 as logo, when option splash=sp\_name is given and menu=on, If 476 firmware/BIOS supports them. Currently Seabios for X86 system 477 support it. limitation: The splash file could be a jpeg file or a 478 BMP file in 24 BPP format(true color). The resolution should be 479 supported by the SVGA mode, so the recommended is 320x240, 640x480, 480 800x640. 481 482 A timeout could be passed to bios, guest will pause for rb\_timeout 483 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 484 not reboot, qemu passes '-1' to bios by default. Currently Seabios 485 for X86 system support it. 486 487 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 488 it. This only effects when boot priority is changed by bootindex 489 options. The default is non-strict boot. 490 491 .. parsed-literal:: 492 493 # try to boot from network first, then from hard disk 494 |qemu_system_x86| -boot order=nc 495 # boot from CD-ROM first, switch back to default order after reboot 496 |qemu_system_x86| -boot once=d 497 # boot with a splash picture for 5 seconds. 498 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 499 500 Note: The legacy format '-boot drives' is still supported but its 501 use is discouraged as it may be removed from future versions. 502ERST 503 504DEF("m", HAS_ARG, QEMU_OPTION_m, 505 "-m [size=]megs[,slots=n,maxmem=size]\n" 506 " configure guest RAM\n" 507 " size: initial amount of guest memory\n" 508 " slots: number of hotplug slots (default: none)\n" 509 " maxmem: maximum amount of guest memory (default: none)\n" 510 "NOTE: Some architectures might enforce a specific granularity\n", 511 QEMU_ARCH_ALL) 512SRST 513``-m [size=]megs[,slots=n,maxmem=size]`` 514 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 515 Optionally, a suffix of "M" or "G" can be used to signify a value in 516 megabytes or gigabytes respectively. Optional pair slots, maxmem 517 could be used to set amount of hotpluggable memory slots and maximum 518 amount of memory. Note that maxmem must be aligned to the page size. 519 520 For example, the following command-line sets the guest startup RAM 521 size to 1GB, creates 3 slots to hotplug additional memory and sets 522 the maximum memory the guest can reach to 4GB: 523 524 .. parsed-literal:: 525 526 |qemu_system| -m 1G,slots=3,maxmem=4G 527 528 If slots and maxmem are not specified, memory hotplug won't be 529 enabled and the guest startup RAM will never increase. 530ERST 531 532DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 533 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 534SRST 535``-mem-path path`` 536 Allocate guest RAM from a temporarily created file in path. 537ERST 538 539DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 540 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 541 QEMU_ARCH_ALL) 542SRST 543``-mem-prealloc`` 544 Preallocate memory when using -mem-path. 545ERST 546 547DEF("k", HAS_ARG, QEMU_OPTION_k, 548 "-k language use keyboard layout (for example 'fr' for French)\n", 549 QEMU_ARCH_ALL) 550SRST 551``-k language`` 552 Use keyboard layout language (for example ``fr`` for French). This 553 option is only needed where it is not easy to get raw PC keycodes 554 (e.g. on Macs, with some X11 servers or with a VNC or curses 555 display). You don't normally need to use it on PC/Linux or 556 PC/Windows hosts. 557 558 The available layouts are: 559 560 :: 561 562 ar de-ch es fo fr-ca hu ja mk no pt-br sv 563 da en-gb et fr fr-ch is lt nl pl ru th 564 de en-us fi fr-be hr it lv nl-be pt sl tr 565 566 The default is ``en-us``. 567ERST 568 569 570HXCOMM Deprecated by -audiodev 571DEF("audio-help", 0, QEMU_OPTION_audio_help, 572 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 573 QEMU_ARCH_ALL) 574SRST 575``-audio-help`` 576 Will show the -audiodev equivalent of the currently specified 577 (deprecated) environment variables. 578ERST 579 580DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 581 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 582 " specifies the audio backend to use\n" 583 " id= identifier of the backend\n" 584 " timer-period= timer period in microseconds\n" 585 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 586 " in|out.fixed-settings= use fixed settings for host audio\n" 587 " in|out.frequency= frequency to use with fixed settings\n" 588 " in|out.channels= number of channels to use with fixed settings\n" 589 " in|out.format= sample format to use with fixed settings\n" 590 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 591 " in|out.voices= number of voices to use\n" 592 " in|out.buffer-length= length of buffer in microseconds\n" 593 "-audiodev none,id=id,[,prop[=value][,...]]\n" 594 " dummy driver that discards all output\n" 595#ifdef CONFIG_AUDIO_ALSA 596 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 597 " in|out.dev= name of the audio device to use\n" 598 " in|out.period-length= length of period in microseconds\n" 599 " in|out.try-poll= attempt to use poll mode\n" 600 " threshold= threshold (in microseconds) when playback starts\n" 601#endif 602#ifdef CONFIG_AUDIO_COREAUDIO 603 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 604 " in|out.buffer-count= number of buffers\n" 605#endif 606#ifdef CONFIG_AUDIO_DSOUND 607 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 608 " latency= add extra latency to playback in microseconds\n" 609#endif 610#ifdef CONFIG_AUDIO_OSS 611 "-audiodev oss,id=id[,prop[=value][,...]]\n" 612 " in|out.dev= path of the audio device to use\n" 613 " in|out.buffer-count= number of buffers\n" 614 " in|out.try-poll= attempt to use poll mode\n" 615 " try-mmap= try using memory mapped access\n" 616 " exclusive= open device in exclusive mode\n" 617 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 618#endif 619#ifdef CONFIG_AUDIO_PA 620 "-audiodev pa,id=id[,prop[=value][,...]]\n" 621 " server= PulseAudio server address\n" 622 " in|out.name= source/sink device name\n" 623 " in|out.latency= desired latency in microseconds\n" 624#endif 625#ifdef CONFIG_AUDIO_SDL 626 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 627 " in|out.buffer-count= number of buffers\n" 628#endif 629#ifdef CONFIG_SPICE 630 "-audiodev spice,id=id[,prop[=value][,...]]\n" 631#endif 632 "-audiodev wav,id=id[,prop[=value][,...]]\n" 633 " path= path of wav file to record\n", 634 QEMU_ARCH_ALL) 635SRST 636``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 637 Adds a new audio backend driver identified by id. There are global 638 and driver specific properties. Some values can be set differently 639 for input and output, they're marked with ``in|out.``. You can set 640 the input's property with ``in.prop`` and the output's property with 641 ``out.prop``. For example: 642 643 :: 644 645 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 646 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 647 648 NOTE: parameter validation is known to be incomplete, in many cases 649 specifying an invalid option causes QEMU to print an error message 650 and continue emulation without sound. 651 652 Valid global options are: 653 654 ``id=identifier`` 655 Identifies the audio backend. 656 657 ``timer-period=period`` 658 Sets the timer period used by the audio subsystem in 659 microseconds. Default is 10000 (10 ms). 660 661 ``in|out.mixing-engine=on|off`` 662 Use QEMU's mixing engine to mix all streams inside QEMU and 663 convert audio formats when not supported by the backend. When 664 off, fixed-settings must be off too. Note that disabling this 665 option means that the selected backend must support multiple 666 streams and the audio formats used by the virtual cards, 667 otherwise you'll get no sound. It's not recommended to disable 668 this option unless you want to use 5.1 or 7.1 audio, as mixing 669 engine only supports mono and stereo audio. Default is on. 670 671 ``in|out.fixed-settings=on|off`` 672 Use fixed settings for host audio. When off, it will change 673 based on how the guest opens the sound card. In this case you 674 must not specify frequency, channels or format. Default is on. 675 676 ``in|out.frequency=frequency`` 677 Specify the frequency to use when using fixed-settings. Default 678 is 44100Hz. 679 680 ``in|out.channels=channels`` 681 Specify the number of channels to use when using fixed-settings. 682 Default is 2 (stereo). 683 684 ``in|out.format=format`` 685 Specify the sample format to use when using fixed-settings. 686 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 687 ``u32``, ``f32``. Default is ``s16``. 688 689 ``in|out.voices=voices`` 690 Specify the number of voices to use. Default is 1. 691 692 ``in|out.buffer-length=usecs`` 693 Sets the size of the buffer in microseconds. 694 695``-audiodev none,id=id[,prop[=value][,...]]`` 696 Creates a dummy backend that discards all outputs. This backend has 697 no backend specific properties. 698 699``-audiodev alsa,id=id[,prop[=value][,...]]`` 700 Creates backend using the ALSA. This backend is only available on 701 Linux. 702 703 ALSA specific options are: 704 705 ``in|out.dev=device`` 706 Specify the ALSA device to use for input and/or output. Default 707 is ``default``. 708 709 ``in|out.period-length=usecs`` 710 Sets the period length in microseconds. 711 712 ``in|out.try-poll=on|off`` 713 Attempt to use poll mode with the device. Default is on. 714 715 ``threshold=threshold`` 716 Threshold (in microseconds) when playback starts. Default is 0. 717 718``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 719 Creates a backend using Apple's Core Audio. This backend is only 720 available on Mac OS and only supports playback. 721 722 Core Audio specific options are: 723 724 ``in|out.buffer-count=count`` 725 Sets the count of the buffers. 726 727``-audiodev dsound,id=id[,prop[=value][,...]]`` 728 Creates a backend using Microsoft's DirectSound. This backend is 729 only available on Windows and only supports playback. 730 731 DirectSound specific options are: 732 733 ``latency=usecs`` 734 Add extra usecs microseconds latency to playback. Default is 735 10000 (10 ms). 736 737``-audiodev oss,id=id[,prop[=value][,...]]`` 738 Creates a backend using OSS. This backend is available on most 739 Unix-like systems. 740 741 OSS specific options are: 742 743 ``in|out.dev=device`` 744 Specify the file name of the OSS device to use. Default is 745 ``/dev/dsp``. 746 747 ``in|out.buffer-count=count`` 748 Sets the count of the buffers. 749 750 ``in|out.try-poll=on|of`` 751 Attempt to use poll mode with the device. Default is on. 752 753 ``try-mmap=on|off`` 754 Try using memory mapped device access. Default is off. 755 756 ``exclusive=on|off`` 757 Open the device in exclusive mode (vmix won't work in this 758 case). Default is off. 759 760 ``dsp-policy=policy`` 761 Sets the timing policy (between 0 and 10, where smaller number 762 means smaller latency but higher CPU usage). Use -1 to use 763 buffer sizes specified by ``buffer`` and ``buffer-count``. This 764 option is ignored if you do not have OSS 4. Default is 5. 765 766``-audiodev pa,id=id[,prop[=value][,...]]`` 767 Creates a backend using PulseAudio. This backend is available on 768 most systems. 769 770 PulseAudio specific options are: 771 772 ``server=server`` 773 Sets the PulseAudio server to connect to. 774 775 ``in|out.name=sink`` 776 Use the specified source/sink for recording/playback. 777 778 ``in|out.latency=usecs`` 779 Desired latency in microseconds. The PulseAudio server will try 780 to honor this value but actual latencies may be lower or higher. 781 782``-audiodev sdl,id=id[,prop[=value][,...]]`` 783 Creates a backend using SDL. This backend is available on most 784 systems, but you should use your platform's native backend if 785 possible. 786 787 SDL specific options are: 788 789 ``in|out.buffer-count=count`` 790 Sets the count of the buffers. 791 792``-audiodev spice,id=id[,prop[=value][,...]]`` 793 Creates a backend that sends audio through SPICE. This backend 794 requires ``-spice`` and automatically selected in that case, so 795 usually you can ignore this option. This backend has no backend 796 specific properties. 797 798``-audiodev wav,id=id[,prop[=value][,...]]`` 799 Creates a backend that writes audio to a WAV file. 800 801 Backend specific options are: 802 803 ``path=path`` 804 Write recorded audio into the specified file. Default is 805 ``qemu.wav``. 806ERST 807 808DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 809 "-soundhw c1,... enable audio support\n" 810 " and only specified sound cards (comma separated list)\n" 811 " use '-soundhw help' to get the list of supported cards\n" 812 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 813SRST 814``-soundhw card1[,card2,...] or -soundhw all`` 815 Enable audio and selected sound hardware. Use 'help' to print all 816 available sound hardware. For example: 817 818 .. parsed-literal:: 819 820 |qemu_system_x86| -soundhw sb16,adlib disk.img 821 |qemu_system_x86| -soundhw es1370 disk.img 822 |qemu_system_x86| -soundhw ac97 disk.img 823 |qemu_system_x86| -soundhw hda disk.img 824 |qemu_system_x86| -soundhw all disk.img 825 |qemu_system_x86| -soundhw help 826 827 Note that Linux's i810\_audio OSS kernel (for AC97) module might 828 require manually specifying clocking. 829 830 :: 831 832 modprobe i810_audio clocking=48000 833ERST 834 835DEF("device", HAS_ARG, QEMU_OPTION_device, 836 "-device driver[,prop[=value][,...]]\n" 837 " add device (based on driver)\n" 838 " prop=value,... sets driver properties\n" 839 " use '-device help' to print all possible drivers\n" 840 " use '-device driver,help' to print all possible properties\n", 841 QEMU_ARCH_ALL) 842SRST 843``-device driver[,prop[=value][,...]]`` 844 Add device driver. prop=value sets driver properties. Valid 845 properties depend on the driver. To get help on possible drivers and 846 properties, use ``-device help`` and ``-device driver,help``. 847 848 Some drivers are: 849 850``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 851 Add an IPMI BMC. This is a simulation of a hardware management 852 interface processor that normally sits on a system. It provides a 853 watchdog and the ability to reset and power control the system. You 854 need to connect this to an IPMI interface to make it useful 855 856 The IPMI slave address to use for the BMC. The default is 0x20. This 857 address is the BMC's address on the I2C network of management 858 controllers. If you don't know what this means, it is safe to ignore 859 it. 860 861 ``id=id`` 862 The BMC id for interfaces to use this device. 863 864 ``slave_addr=val`` 865 Define slave address to use for the BMC. The default is 0x20. 866 867 ``sdrfile=file`` 868 file containing raw Sensor Data Records (SDR) data. The default 869 is none. 870 871 ``fruareasize=val`` 872 size of a Field Replaceable Unit (FRU) area. The default is 873 1024. 874 875 ``frudatafile=file`` 876 file containing raw Field Replaceable Unit (FRU) inventory data. 877 The default is none. 878 879 ``guid=uuid`` 880 value for the GUID for the BMC, in standard UUID format. If this 881 is set, get "Get GUID" command to the BMC will return it. 882 Otherwise "Get GUID" will return an error. 883 884``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 885 Add a connection to an external IPMI BMC simulator. Instead of 886 locally emulating the BMC like the above item, instead connect to an 887 external entity that provides the IPMI services. 888 889 A connection is made to an external BMC simulator. If you do this, 890 it is strongly recommended that you use the "reconnect=" chardev 891 option to reconnect to the simulator if the connection is lost. Note 892 that if this is not used carefully, it can be a security issue, as 893 the interface has the ability to send resets, NMIs, and power off 894 the VM. It's best if QEMU makes a connection to an external 895 simulator running on a secure port on localhost, so neither the 896 simulator nor QEMU is exposed to any outside network. 897 898 See the "lanserv/README.vm" file in the OpenIPMI library for more 899 details on the external interface. 900 901``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 902 Add a KCS IPMI interafce on the ISA bus. This also adds a 903 corresponding ACPI and SMBIOS entries, if appropriate. 904 905 ``bmc=id`` 906 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 907 above. 908 909 ``ioport=val`` 910 Define the I/O address of the interface. The default is 0xca0 911 for KCS. 912 913 ``irq=val`` 914 Define the interrupt to use. The default is 5. To disable 915 interrupts, set this to 0. 916 917``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 918 Like the KCS interface, but defines a BT interface. The default port 919 is 0xe4 and the default interrupt is 5. 920 921``-device pci-ipmi-kcs,bmc=id`` 922 Add a KCS IPMI interafce on the PCI bus. 923 924 ``bmc=id`` 925 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 926 927``-device pci-ipmi-bt,bmc=id`` 928 Like the KCS interface, but defines a BT interface on the PCI bus. 929ERST 930 931DEF("name", HAS_ARG, QEMU_OPTION_name, 932 "-name string1[,process=string2][,debug-threads=on|off]\n" 933 " set the name of the guest\n" 934 " string1 sets the window title and string2 the process name\n" 935 " When debug-threads is enabled, individual threads are given a separate name\n" 936 " NOTE: The thread names are for debugging and not a stable API.\n", 937 QEMU_ARCH_ALL) 938SRST 939``-name name`` 940 Sets the name of the guest. This name will be displayed in the SDL 941 window caption. The name will also be used for the VNC server. Also 942 optionally set the top visible process name in Linux. Naming of 943 individual threads can also be enabled on Linux to aid debugging. 944ERST 945 946DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 947 "-uuid %08x-%04x-%04x-%04x-%012x\n" 948 " specify machine UUID\n", QEMU_ARCH_ALL) 949SRST 950``-uuid uuid`` 951 Set system UUID. 952ERST 953 954DEFHEADING() 955 956DEFHEADING(Block device options:) 957 958DEF("fda", HAS_ARG, QEMU_OPTION_fda, 959 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 960DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 961SRST 962``-fda file`` 963 \ 964``-fdb file`` 965 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 966 the System Emulation Users Guide). 967ERST 968 969DEF("hda", HAS_ARG, QEMU_OPTION_hda, 970 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 971DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 972DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 973 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 974DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 975SRST 976``-hda file`` 977 \ 978``-hdb file`` 979 \ 980``-hdc file`` 981 \ 982``-hdd file`` 983 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 984 chapter in the System Emulation Users Guide). 985ERST 986 987DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 988 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 989 QEMU_ARCH_ALL) 990SRST 991``-cdrom file`` 992 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 993 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 994 as filename. 995ERST 996 997DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 998 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 999 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1000 " [,read-only=on|off][,auto-read-only=on|off]\n" 1001 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1002 " [,driver specific parameters...]\n" 1003 " configure a block backend\n", QEMU_ARCH_ALL) 1004SRST 1005``-blockdev option[,option[,option[,...]]]`` 1006 Define a new block driver node. Some of the options apply to all 1007 block drivers, other options are only accepted for a specific block 1008 driver. See below for a list of generic options and options for the 1009 most common block drivers. 1010 1011 Options that expect a reference to another node (e.g. ``file``) can 1012 be given in two ways. Either you specify the node name of an already 1013 existing node (file=node-name), or you define a new node inline, 1014 adding options for the referenced node after a dot 1015 (file.filename=path,file.aio=native). 1016 1017 A block driver node created with ``-blockdev`` can be used for a 1018 guest device by specifying its node name for the ``drive`` property 1019 in a ``-device`` argument that defines a block device. 1020 1021 ``Valid options for any block driver node:`` 1022 ``driver`` 1023 Specifies the block driver to use for the given node. 1024 1025 ``node-name`` 1026 This defines the name of the block driver node by which it 1027 will be referenced later. The name must be unique, i.e. it 1028 must not match the name of a different block driver node, or 1029 (if you use ``-drive`` as well) the ID of a drive. 1030 1031 If no node name is specified, it is automatically generated. 1032 The generated node name is not intended to be predictable 1033 and changes between QEMU invocations. For the top level, an 1034 explicit node name must be specified. 1035 1036 ``read-only`` 1037 Open the node read-only. Guest write attempts will fail. 1038 1039 Note that some block drivers support only read-only access, 1040 either generally or in certain configurations. In this case, 1041 the default value ``read-only=off`` does not work and the 1042 option must be specified explicitly. 1043 1044 ``auto-read-only`` 1045 If ``auto-read-only=on`` is set, QEMU may fall back to 1046 read-only usage even when ``read-only=off`` is requested, or 1047 even switch between modes as needed, e.g. depending on 1048 whether the image file is writable or whether a writing user 1049 is attached to the node. 1050 1051 ``force-share`` 1052 Override the image locking system of QEMU by forcing the 1053 node to utilize weaker shared access for permissions where 1054 it would normally request exclusive access. When there is 1055 the potential for multiple instances to have the same file 1056 open (whether this invocation of QEMU is the first or the 1057 second instance), both instances must permit shared access 1058 for the second instance to succeed at opening the file. 1059 1060 Enabling ``force-share=on`` requires ``read-only=on``. 1061 1062 ``cache.direct`` 1063 The host page cache can be avoided with ``cache.direct=on``. 1064 This will attempt to do disk IO directly to the guest's 1065 memory. QEMU may still perform an internal copy of the data. 1066 1067 ``cache.no-flush`` 1068 In case you don't care about data integrity over host 1069 failures, you can use ``cache.no-flush=on``. This option 1070 tells QEMU that it never needs to write any data to the disk 1071 but can instead keep things in cache. If anything goes 1072 wrong, like your host losing power, the disk storage getting 1073 disconnected accidentally, etc. your image will most 1074 probably be rendered unusable. 1075 1076 ``discard=discard`` 1077 discard is one of "ignore" (or "off") or "unmap" (or "on") 1078 and controls whether ``discard`` (also known as ``trim`` or 1079 ``unmap``) requests are ignored or passed to the filesystem. 1080 Some machine types may not support discard requests. 1081 1082 ``detect-zeroes=detect-zeroes`` 1083 detect-zeroes is "off", "on" or "unmap" and enables the 1084 automatic conversion of plain zero writes by the OS to 1085 driver specific optimized zero write commands. You may even 1086 choose "unmap" if discard is set to "unmap" to allow a zero 1087 write to be converted to an ``unmap`` operation. 1088 1089 ``Driver-specific options for file`` 1090 This is the protocol-level block driver for accessing regular 1091 files. 1092 1093 ``filename`` 1094 The path to the image file in the local filesystem 1095 1096 ``aio`` 1097 Specifies the AIO backend (threads/native/io_uring, 1098 default: threads) 1099 1100 ``locking`` 1101 Specifies whether the image file is protected with Linux OFD 1102 / POSIX locks. The default is to use the Linux Open File 1103 Descriptor API if available, otherwise no lock is applied. 1104 (auto/on/off, default: auto) 1105 1106 Example: 1107 1108 :: 1109 1110 -blockdev driver=file,node-name=disk,filename=disk.img 1111 1112 ``Driver-specific options for raw`` 1113 This is the image format block driver for raw images. It is 1114 usually stacked on top of a protocol level block driver such as 1115 ``file``. 1116 1117 ``file`` 1118 Reference to or definition of the data source block driver 1119 node (e.g. a ``file`` driver node) 1120 1121 Example 1: 1122 1123 :: 1124 1125 -blockdev driver=file,node-name=disk_file,filename=disk.img 1126 -blockdev driver=raw,node-name=disk,file=disk_file 1127 1128 Example 2: 1129 1130 :: 1131 1132 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1133 1134 ``Driver-specific options for qcow2`` 1135 This is the image format block driver for qcow2 images. It is 1136 usually stacked on top of a protocol level block driver such as 1137 ``file``. 1138 1139 ``file`` 1140 Reference to or definition of the data source block driver 1141 node (e.g. a ``file`` driver node) 1142 1143 ``backing`` 1144 Reference to or definition of the backing file block device 1145 (default is taken from the image file). It is allowed to 1146 pass ``null`` here in order to disable the default backing 1147 file. 1148 1149 ``lazy-refcounts`` 1150 Whether to enable the lazy refcounts feature (on/off; 1151 default is taken from the image file) 1152 1153 ``cache-size`` 1154 The maximum total size of the L2 table and refcount block 1155 caches in bytes (default: the sum of l2-cache-size and 1156 refcount-cache-size) 1157 1158 ``l2-cache-size`` 1159 The maximum size of the L2 table cache in bytes (default: if 1160 cache-size is not specified - 32M on Linux platforms, and 8M 1161 on non-Linux platforms; otherwise, as large as possible 1162 within the cache-size, while permitting the requested or the 1163 minimal refcount cache size) 1164 1165 ``refcount-cache-size`` 1166 The maximum size of the refcount block cache in bytes 1167 (default: 4 times the cluster size; or if cache-size is 1168 specified, the part of it which is not used for the L2 1169 cache) 1170 1171 ``cache-clean-interval`` 1172 Clean unused entries in the L2 and refcount caches. The 1173 interval is in seconds. The default value is 600 on 1174 supporting platforms, and 0 on other platforms. Setting it 1175 to 0 disables this feature. 1176 1177 ``pass-discard-request`` 1178 Whether discard requests to the qcow2 device should be 1179 forwarded to the data source (on/off; default: on if 1180 discard=unmap is specified, off otherwise) 1181 1182 ``pass-discard-snapshot`` 1183 Whether discard requests for the data source should be 1184 issued when a snapshot operation (e.g. deleting a snapshot) 1185 frees clusters in the qcow2 file (on/off; default: on) 1186 1187 ``pass-discard-other`` 1188 Whether discard requests for the data source should be 1189 issued on other occasions where a cluster gets freed 1190 (on/off; default: off) 1191 1192 ``overlap-check`` 1193 Which overlap checks to perform for writes to the image 1194 (none/constant/cached/all; default: cached). For details or 1195 finer granularity control refer to the QAPI documentation of 1196 ``blockdev-add``. 1197 1198 Example 1: 1199 1200 :: 1201 1202 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1203 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1204 1205 Example 2: 1206 1207 :: 1208 1209 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1210 1211 ``Driver-specific options for other drivers`` 1212 Please refer to the QAPI documentation of the ``blockdev-add`` 1213 QMP command. 1214ERST 1215 1216DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1217 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1218 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1219 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1220 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1221 " [,aio=threads|native|io_uring]\n" 1222 " [,readonly=on|off][,copy-on-read=on|off]\n" 1223 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1224 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1225 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1226 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1227 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1228 " [[,iops_size=is]]\n" 1229 " [[,group=g]]\n" 1230 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1231SRST 1232``-drive option[,option[,option[,...]]]`` 1233 Define a new drive. This includes creating a block driver node (the 1234 backend) as well as a guest device, and is mostly a shortcut for 1235 defining the corresponding ``-blockdev`` and ``-device`` options. 1236 1237 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1238 In addition, it knows the following options: 1239 1240 ``file=file`` 1241 This option defines which disk image (see the :ref:`disk images` 1242 chapter in the System Emulation Users Guide) to use with this drive. 1243 If the filename contains comma, you must double it (for instance, 1244 "file=my,,file" to use file "my,file"). 1245 1246 Special files such as iSCSI devices can be specified using 1247 protocol specific URLs. See the section for "Device URL Syntax" 1248 for more information. 1249 1250 ``if=interface`` 1251 This option defines on which type on interface the drive is 1252 connected. Available types are: ide, scsi, sd, mtd, floppy, 1253 pflash, virtio, none. 1254 1255 ``bus=bus,unit=unit`` 1256 These options define where is connected the drive by defining 1257 the bus number and the unit id. 1258 1259 ``index=index`` 1260 This option defines where is connected the drive by using an 1261 index in the list of available connectors of a given interface 1262 type. 1263 1264 ``media=media`` 1265 This option defines the type of the media: disk or cdrom. 1266 1267 ``snapshot=snapshot`` 1268 snapshot is "on" or "off" and controls snapshot mode for the 1269 given drive (see ``-snapshot``). 1270 1271 ``cache=cache`` 1272 cache is "none", "writeback", "unsafe", "directsync" or 1273 "writethrough" and controls how the host cache is used to access 1274 block data. This is a shortcut that sets the ``cache.direct`` 1275 and ``cache.no-flush`` options (as in ``-blockdev``), and 1276 additionally ``cache.writeback``, which provides a default for 1277 the ``write-cache`` option of block guest devices (as in 1278 ``-device``). The modes correspond to the following settings: 1279 1280 ============= =============== ============ ============== 1281 \ cache.writeback cache.direct cache.no-flush 1282 ============= =============== ============ ============== 1283 writeback on off off 1284 none on on off 1285 writethrough off off off 1286 directsync off on off 1287 unsafe on off on 1288 ============= =============== ============ ============== 1289 1290 The default mode is ``cache=writeback``. 1291 1292 ``aio=aio`` 1293 aio is "threads", "native", or "io_uring" and selects between pthread 1294 based disk I/O, native Linux AIO, or Linux io_uring API. 1295 1296 ``format=format`` 1297 Specify which disk format will be used rather than detecting the 1298 format. Can be used to specify format=raw to avoid interpreting 1299 an untrusted format header. 1300 1301 ``werror=action,rerror=action`` 1302 Specify which action to take on write and read errors. Valid 1303 actions are: "ignore" (ignore the error and try to continue), 1304 "stop" (pause QEMU), "report" (report the error to the guest), 1305 "enospc" (pause QEMU only if the host disk is full; report the 1306 error to the guest otherwise). The default setting is 1307 ``werror=enospc`` and ``rerror=report``. 1308 1309 ``copy-on-read=copy-on-read`` 1310 copy-on-read is "on" or "off" and enables whether to copy read 1311 backing file sectors into the image file. 1312 1313 ``bps=b,bps_rd=r,bps_wr=w`` 1314 Specify bandwidth throttling limits in bytes per second, either 1315 for all request types or for reads or writes only. Small values 1316 can lead to timeouts or hangs inside the guest. A safe minimum 1317 for disks is 2 MB/s. 1318 1319 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1320 Specify bursts in bytes per second, either for all request types 1321 or for reads or writes only. Bursts allow the guest I/O to spike 1322 above the limit temporarily. 1323 1324 ``iops=i,iops_rd=r,iops_wr=w`` 1325 Specify request rate limits in requests per second, either for 1326 all request types or for reads or writes only. 1327 1328 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1329 Specify bursts in requests per second, either for all request 1330 types or for reads or writes only. Bursts allow the guest I/O to 1331 spike above the limit temporarily. 1332 1333 ``iops_size=is`` 1334 Let every is bytes of a request count as a new request for iops 1335 throttling purposes. Use this option to prevent guests from 1336 circumventing iops limits by sending fewer but larger requests. 1337 1338 ``group=g`` 1339 Join a throttling quota group with given name g. All drives that 1340 are members of the same group are accounted for together. Use 1341 this option to prevent guests from circumventing throttling 1342 limits by using many small disks instead of a single larger 1343 disk. 1344 1345 By default, the ``cache.writeback=on`` mode is used. It will report 1346 data writes as completed as soon as the data is present in the host 1347 page cache. This is safe as long as your guest OS makes sure to 1348 correctly flush disk caches where needed. If your guest OS does not 1349 handle volatile disk write caches correctly and your host crashes or 1350 loses power, then the guest may experience data corruption. 1351 1352 For such guests, you should consider using ``cache.writeback=off``. 1353 This means that the host page cache will be used to read and write 1354 data, but write notification will be sent to the guest only after 1355 QEMU has made sure to flush each write to the disk. Be aware that 1356 this has a major impact on performance. 1357 1358 When using the ``-snapshot`` option, unsafe caching is always used. 1359 1360 Copy-on-read avoids accessing the same backing file sectors 1361 repeatedly and is useful when the backing file is over a slow 1362 network. By default copy-on-read is off. 1363 1364 Instead of ``-cdrom`` you can use: 1365 1366 .. parsed-literal:: 1367 1368 |qemu_system| -drive file=file,index=2,media=cdrom 1369 1370 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1371 1372 .. parsed-literal:: 1373 1374 |qemu_system| -drive file=file,index=0,media=disk 1375 |qemu_system| -drive file=file,index=1,media=disk 1376 |qemu_system| -drive file=file,index=2,media=disk 1377 |qemu_system| -drive file=file,index=3,media=disk 1378 1379 You can open an image using pre-opened file descriptors from an fd 1380 set: 1381 1382 .. parsed-literal:: 1383 1384 |qemu_system| \\ 1385 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1386 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1387 -drive file=/dev/fdset/2,index=0,media=disk 1388 1389 You can connect a CDROM to the slave of ide0: 1390 1391 .. parsed-literal:: 1392 1393 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1394 1395 If you don't specify the "file=" argument, you define an empty 1396 drive: 1397 1398 .. parsed-literal:: 1399 1400 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1401 1402 Instead of ``-fda``, ``-fdb``, you can use: 1403 1404 .. parsed-literal:: 1405 1406 |qemu_system_x86| -drive file=file,index=0,if=floppy 1407 |qemu_system_x86| -drive file=file,index=1,if=floppy 1408 1409 By default, interface is "ide" and index is automatically 1410 incremented: 1411 1412 .. parsed-literal:: 1413 1414 |qemu_system_x86| -drive file=a -drive file=b" 1415 1416 is interpreted like: 1417 1418 .. parsed-literal:: 1419 1420 |qemu_system_x86| -hda a -hdb b 1421ERST 1422 1423DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1424 "-mtdblock file use 'file' as on-board Flash memory image\n", 1425 QEMU_ARCH_ALL) 1426SRST 1427``-mtdblock file`` 1428 Use file as on-board Flash memory image. 1429ERST 1430 1431DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1432 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1433SRST 1434``-sd file`` 1435 Use file as SecureDigital card image. 1436ERST 1437 1438DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1439 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1440SRST 1441``-pflash file`` 1442 Use file as a parallel flash image. 1443ERST 1444 1445DEF("snapshot", 0, QEMU_OPTION_snapshot, 1446 "-snapshot write to temporary files instead of disk image files\n", 1447 QEMU_ARCH_ALL) 1448SRST 1449``-snapshot`` 1450 Write to temporary files instead of disk image files. In this case, 1451 the raw disk image you use is not written back. You can however 1452 force the write back by pressing C-a s (see the :ref:`disk images` 1453 chapter in the System Emulation Users Guide). 1454ERST 1455 1456DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1457 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1458 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1459 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1460 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1461 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1462 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1463 " [[,throttling.iops-size=is]]\n" 1464 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1465 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1466 "-fsdev synth,id=id\n", 1467 QEMU_ARCH_ALL) 1468 1469SRST 1470``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1471 \ 1472``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1473 \ 1474``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1475 \ 1476``-fsdev synth,id=id[,readonly=on]`` 1477 Define a new file system device. Valid options are: 1478 1479 ``local`` 1480 Accesses to the filesystem are done by QEMU. 1481 1482 ``proxy`` 1483 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1484 1485 ``synth`` 1486 Synthetic filesystem, only used by QTests. 1487 1488 ``id=id`` 1489 Specifies identifier for this device. 1490 1491 ``path=path`` 1492 Specifies the export path for the file system device. Files 1493 under this path will be available to the 9p client on the guest. 1494 1495 ``security_model=security_model`` 1496 Specifies the security model to be used for this export path. 1497 Supported security models are "passthrough", "mapped-xattr", 1498 "mapped-file" and "none". In "passthrough" security model, files 1499 are stored using the same credentials as they are created on the 1500 guest. This requires QEMU to run as root. In "mapped-xattr" 1501 security model, some of the file attributes like uid, gid, mode 1502 bits and link target are stored as file attributes. For 1503 "mapped-file" these attributes are stored in the hidden 1504 .virtfs\_metadata directory. Directories exported by this 1505 security model cannot interact with other unix tools. "none" 1506 security model is same as passthrough except the sever won't 1507 report failures if it fails to set file attributes like 1508 ownership. Security model is mandatory only for local fsdriver. 1509 Other fsdrivers (like proxy) don't take security model as a 1510 parameter. 1511 1512 ``writeout=writeout`` 1513 This is an optional argument. The only supported value is 1514 "immediate". This means that host page cache will be used to 1515 read and write data but write notification will be sent to the 1516 guest only when the data has been reported as written by the 1517 storage subsystem. 1518 1519 ``readonly=on`` 1520 Enables exporting 9p share as a readonly mount for guests. By 1521 default read-write access is given. 1522 1523 ``socket=socket`` 1524 Enables proxy filesystem driver to use passed socket file for 1525 communicating with virtfs-proxy-helper(1). 1526 1527 ``sock_fd=sock_fd`` 1528 Enables proxy filesystem driver to use passed socket descriptor 1529 for communicating with virtfs-proxy-helper(1). Usually a helper 1530 like libvirt will create socketpair and pass one of the fds as 1531 sock\_fd. 1532 1533 ``fmode=fmode`` 1534 Specifies the default mode for newly created files on the host. 1535 Works only with security models "mapped-xattr" and 1536 "mapped-file". 1537 1538 ``dmode=dmode`` 1539 Specifies the default mode for newly created directories on the 1540 host. Works only with security models "mapped-xattr" and 1541 "mapped-file". 1542 1543 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1544 Specify bandwidth throttling limits in bytes per second, either 1545 for all request types or for reads or writes only. 1546 1547 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1548 Specify bursts in bytes per second, either for all request types 1549 or for reads or writes only. Bursts allow the guest I/O to spike 1550 above the limit temporarily. 1551 1552 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1553 Specify request rate limits in requests per second, either for 1554 all request types or for reads or writes only. 1555 1556 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1557 Specify bursts in requests per second, either for all request 1558 types or for reads or writes only. Bursts allow the guest I/O to 1559 spike above the limit temporarily. 1560 1561 ``throttling.iops-size=is`` 1562 Let every is bytes of a request count as a new request for iops 1563 throttling purposes. 1564 1565 -fsdev option is used along with -device driver "virtio-9p-...". 1566 1567``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1568 Options for virtio-9p-... driver are: 1569 1570 ``type`` 1571 Specifies the variant to be used. Supported values are "pci", 1572 "ccw" or "device", depending on the machine type. 1573 1574 ``fsdev=id`` 1575 Specifies the id value specified along with -fsdev option. 1576 1577 ``mount_tag=mount_tag`` 1578 Specifies the tag name to be used by the guest to mount this 1579 export point. 1580ERST 1581 1582DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1583 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1584 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1585 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1586 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1587 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1588 QEMU_ARCH_ALL) 1589 1590SRST 1591``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1592 \ 1593``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1594 \ 1595``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1596 \ 1597``-virtfs synth,mount_tag=mount_tag`` 1598 Define a new virtual filesystem device and expose it to the guest using 1599 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1600 directory on host is made directly accessible by guest as a pass-through 1601 file system by using the 9P network protocol for communication between 1602 host and guests, if desired even accessible, shared by several guests 1603 simultaniously. 1604 1605 Note that ``-virtfs`` is actually just a convenience shortcut for its 1606 generalized form ``-fsdev -device virtio-9p-pci``. 1607 1608 The general form of pass-through file system options are: 1609 1610 ``local`` 1611 Accesses to the filesystem are done by QEMU. 1612 1613 ``proxy`` 1614 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1615 1616 ``synth`` 1617 Synthetic filesystem, only used by QTests. 1618 1619 ``id=id`` 1620 Specifies identifier for the filesystem device 1621 1622 ``path=path`` 1623 Specifies the export path for the file system device. Files 1624 under this path will be available to the 9p client on the guest. 1625 1626 ``security_model=security_model`` 1627 Specifies the security model to be used for this export path. 1628 Supported security models are "passthrough", "mapped-xattr", 1629 "mapped-file" and "none". In "passthrough" security model, files 1630 are stored using the same credentials as they are created on the 1631 guest. This requires QEMU to run as root. In "mapped-xattr" 1632 security model, some of the file attributes like uid, gid, mode 1633 bits and link target are stored as file attributes. For 1634 "mapped-file" these attributes are stored in the hidden 1635 .virtfs\_metadata directory. Directories exported by this 1636 security model cannot interact with other unix tools. "none" 1637 security model is same as passthrough except the sever won't 1638 report failures if it fails to set file attributes like 1639 ownership. Security model is mandatory only for local fsdriver. 1640 Other fsdrivers (like proxy) don't take security model as a 1641 parameter. 1642 1643 ``writeout=writeout`` 1644 This is an optional argument. The only supported value is 1645 "immediate". This means that host page cache will be used to 1646 read and write data but write notification will be sent to the 1647 guest only when the data has been reported as written by the 1648 storage subsystem. 1649 1650 ``readonly=on`` 1651 Enables exporting 9p share as a readonly mount for guests. By 1652 default read-write access is given. 1653 1654 ``socket=socket`` 1655 Enables proxy filesystem driver to use passed socket file for 1656 communicating with virtfs-proxy-helper(1). Usually a helper like 1657 libvirt will create socketpair and pass one of the fds as 1658 sock\_fd. 1659 1660 ``sock_fd`` 1661 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1662 socket descriptor for interfacing with virtfs-proxy-helper(1). 1663 1664 ``fmode=fmode`` 1665 Specifies the default mode for newly created files on the host. 1666 Works only with security models "mapped-xattr" and 1667 "mapped-file". 1668 1669 ``dmode=dmode`` 1670 Specifies the default mode for newly created directories on the 1671 host. Works only with security models "mapped-xattr" and 1672 "mapped-file". 1673 1674 ``mount_tag=mount_tag`` 1675 Specifies the tag name to be used by the guest to mount this 1676 export point. 1677 1678 ``multidevs=multidevs`` 1679 Specifies how to deal with multiple devices being shared with a 1680 9p export. Supported behaviours are either "remap", "forbid" or 1681 "warn". The latter is the default behaviour on which virtfs 9p 1682 expects only one device to be shared with the same export, and 1683 if more than one device is shared and accessed via the same 9p 1684 export then only a warning message is logged (once) by qemu on 1685 host side. In order to avoid file ID collisions on guest you 1686 should either create a separate virtfs export for each device to 1687 be shared with guests (recommended way) or you might use "remap" 1688 instead which allows you to share multiple devices with only one 1689 export instead, which is achieved by remapping the original 1690 inode numbers from host to guest in a way that would prevent 1691 such collisions. Remapping inodes in such use cases is required 1692 because the original device IDs from host are never passed and 1693 exposed on guest. Instead all files of an export shared with 1694 virtfs always share the same device id on guest. So two files 1695 with identical inode numbers but from actually different devices 1696 on host would otherwise cause a file ID collision and hence 1697 potential misbehaviours on guest. "forbid" on the other hand 1698 assumes like "warn" that only one device is shared by the same 1699 export, however it will not only log a warning message but also 1700 deny access to additional devices on guest. Note though that 1701 "forbid" does currently not block all possible file access 1702 operations (e.g. readdir() would still return entries from other 1703 devices). 1704ERST 1705 1706DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1707 "-iscsi [user=user][,password=password]\n" 1708 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1709 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1710 " [,timeout=timeout]\n" 1711 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1712 1713SRST 1714``-iscsi`` 1715 Configure iSCSI session parameters. 1716ERST 1717 1718DEFHEADING() 1719 1720DEFHEADING(USB convenience options:) 1721 1722DEF("usb", 0, QEMU_OPTION_usb, 1723 "-usb enable on-board USB host controller (if not enabled by default)\n", 1724 QEMU_ARCH_ALL) 1725SRST 1726``-usb`` 1727 Enable USB emulation on machine types with an on-board USB host 1728 controller (if not enabled by default). Note that on-board USB host 1729 controllers may not support USB 3.0. In this case 1730 ``-device qemu-xhci`` can be used instead on machines with PCI. 1731ERST 1732 1733DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1734 "-usbdevice name add the host or guest USB device 'name'\n", 1735 QEMU_ARCH_ALL) 1736SRST 1737``-usbdevice devname`` 1738 Add the USB device devname, and enable an on-board USB controller 1739 if possible and necessary (just like it can be done via 1740 ``-machine usb=on``). Note that this option is mainly intended for 1741 the user's convenience only. More fine-grained control can be 1742 achieved by selecting a USB host controller (if necessary) and the 1743 desired USB device via the ``-device`` option instead. For example, 1744 instead of using ``-usbdevice mouse`` it is possible to use 1745 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1746 to a USB 3.0 controller instead (at least on machines that support 1747 PCI and do not have an USB controller enabled by default yet). 1748 For more details, see the chapter about 1749 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1750 Possible devices for devname are: 1751 1752 ``braille`` 1753 Braille device. This will use BrlAPI to display the braille 1754 output on a real or fake device (i.e. it also creates a 1755 corresponding ``braille`` chardev automatically beside the 1756 ``usb-braille`` USB device). 1757 1758 ``keyboard`` 1759 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1760 1761 ``mouse`` 1762 Virtual Mouse. This will override the PS/2 mouse emulation when 1763 activated. 1764 1765 ``tablet`` 1766 Pointer device that uses absolute coordinates (like a 1767 touchscreen). This means QEMU is able to report the mouse 1768 position without having to grab the mouse. Also overrides the 1769 PS/2 mouse emulation when activated. 1770 1771 ``wacom-tablet`` 1772 Wacom PenPartner USB tablet. 1773 1774 1775ERST 1776 1777DEFHEADING() 1778 1779DEFHEADING(Display options:) 1780 1781DEF("display", HAS_ARG, QEMU_OPTION_display, 1782#if defined(CONFIG_SPICE) 1783 "-display spice-app[,gl=on|off]\n" 1784#endif 1785#if defined(CONFIG_SDL) 1786 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1787 " [,window_close=on|off][,gl=on|core|es|off]\n" 1788#endif 1789#if defined(CONFIG_GTK) 1790 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1791#endif 1792#if defined(CONFIG_VNC) 1793 "-display vnc=<display>[,<optargs>]\n" 1794#endif 1795#if defined(CONFIG_CURSES) 1796 "-display curses[,charset=<encoding>]\n" 1797#endif 1798#if defined(CONFIG_OPENGL) 1799 "-display egl-headless[,rendernode=<file>]\n" 1800#endif 1801 "-display none\n" 1802 " select display backend type\n" 1803 " The default display is equivalent to\n " 1804#if defined(CONFIG_GTK) 1805 "\"-display gtk\"\n" 1806#elif defined(CONFIG_SDL) 1807 "\"-display sdl\"\n" 1808#elif defined(CONFIG_COCOA) 1809 "\"-display cocoa\"\n" 1810#elif defined(CONFIG_VNC) 1811 "\"-vnc localhost:0,to=99,id=default\"\n" 1812#else 1813 "\"-display none\"\n" 1814#endif 1815 , QEMU_ARCH_ALL) 1816SRST 1817``-display type`` 1818 Select type of display to use. This option is a replacement for the 1819 old style -sdl/-curses/... options. Use ``-display help`` to list 1820 the available display types. Valid values for type are 1821 1822 ``spice-app[,gl=on|off]`` 1823 Start QEMU as a Spice server and launch the default Spice client 1824 application. The Spice server will redirect the serial consoles 1825 and QEMU monitors. (Since 4.0) 1826 1827 ``sdl[,window-close=on|off][,gl=on|core|es|off]`` 1828 1829 Display video output via SDL (usually in a separate graphics 1830 window; see the SDL documentation for other possibilities). 1831 1832 ``gtk[,grab-on-hover=on|off][,gl=on|off]`` 1833 Display video output in a GTK window. This interface provides 1834 drop-down menus and other UI elements to configure and control 1835 the VM during runtime. 1836 1837 ``curses [,charset=<encoding>]`` 1838 Display video output via curses. For graphics device models 1839 which support a text mode, QEMU can display this output using a 1840 curses/ncurses interface. Nothing is displayed when the graphics 1841 device is in graphical mode or if the graphics device does not 1842 support a text mode. Generally only the VGA device models 1843 support text mode. The font charset used by the guest can be 1844 specified with the ``charset`` option, for example 1845 ``charset=CP850`` for IBM CP850 encoding. The default is 1846 ``CP437``. 1847 1848 ``egl-headless[,rendernode<file>]`` 1849 Offload all OpenGL operations to a local DRI device. For any 1850 graphical display, this display needs to be paired with either 1851 VNC or SPICE displays. 1852 1853 ``none`` 1854 Do not display video output. The guest will still see an 1855 emulated graphics card, but its output will not be displayed to 1856 the QEMU user. This option differs from the -nographic option in 1857 that it only affects what is done with video output; -nographic 1858 also changes the destination of the serial and parallel port 1859 data. 1860 1861 1862 1863ERST 1864 1865DEF("nographic", 0, QEMU_OPTION_nographic, 1866 "-nographic disable graphical output and redirect serial I/Os to console\n", 1867 QEMU_ARCH_ALL) 1868SRST 1869``-nographic`` 1870 Normally, if QEMU is compiled with graphical window support, it 1871 displays output such as guest graphics, guest console, and the QEMU 1872 monitor in a window. With this option, you can totally disable 1873 graphical output so that QEMU is a simple command line application. 1874 The emulated serial port is redirected on the console and muxed with 1875 the monitor (unless redirected elsewhere explicitly). Therefore, you 1876 can still use QEMU to debug a Linux kernel with a serial console. 1877 Use C-a h for help on switching between the console and monitor. 1878ERST 1879 1880DEF("curses", 0, QEMU_OPTION_curses, 1881 "-curses shorthand for -display curses\n", 1882 QEMU_ARCH_ALL) 1883SRST 1884``-curses`` 1885 Normally, if QEMU is compiled with graphical window support, it 1886 displays output such as guest graphics, guest console, and the QEMU 1887 monitor in a window. With this option, QEMU can display the VGA 1888 output when in text mode using a curses/ncurses interface. Nothing 1889 is displayed in graphical mode. 1890ERST 1891 1892DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1893 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1894 QEMU_ARCH_ALL) 1895SRST 1896``-alt-grab`` 1897 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1898 this also affects the special keys (for fullscreen, monitor-mode 1899 switching, etc). 1900ERST 1901 1902DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1903 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1904 QEMU_ARCH_ALL) 1905SRST 1906``-ctrl-grab`` 1907 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1908 also affects the special keys (for fullscreen, monitor-mode 1909 switching, etc). 1910ERST 1911 1912DEF("no-quit", 0, QEMU_OPTION_no_quit, 1913 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1914SRST 1915``-no-quit`` 1916 Disable SDL window close capability. 1917ERST 1918 1919DEF("sdl", 0, QEMU_OPTION_sdl, 1920 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1921SRST 1922``-sdl`` 1923 Enable SDL. 1924ERST 1925 1926DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1927 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1928 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1929 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1930 " [,x509-dh-key-file=<file>][,addr=addr]\n" 1931 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 1932 " [,tls-ciphers=<list>]\n" 1933 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1934 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1935 " [,sasl=on|off][,disable-ticketing=on|off]\n" 1936 " [,password=<string>][,password-secret=<secret-id>]\n" 1937 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1938 " [,jpeg-wan-compression=[auto|never|always]]\n" 1939 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1940 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 1941 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 1942 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1943 " [,gl=[on|off]][,rendernode=<file>]\n" 1944 " enable spice\n" 1945 " at least one of {port, tls-port} is mandatory\n", 1946 QEMU_ARCH_ALL) 1947SRST 1948``-spice option[,option[,...]]`` 1949 Enable the spice remote desktop protocol. Valid options are 1950 1951 ``port=<nr>`` 1952 Set the TCP port spice is listening on for plaintext channels. 1953 1954 ``addr=<addr>`` 1955 Set the IP address spice is listening on. Default is any 1956 address. 1957 1958 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 1959 Force using the specified IP version. 1960 1961 ``password=<string>`` 1962 Set the password you need to authenticate. 1963 1964 This option is deprecated and insecure because it leaves the 1965 password visible in the process listing. Use ``password-secret`` 1966 instead. 1967 1968 ``password-secret=<secret-id>`` 1969 Set the ID of the ``secret`` object containing the password 1970 you need to authenticate. 1971 1972 ``sasl=on|off`` 1973 Require that the client use SASL to authenticate with the spice. 1974 The exact choice of authentication method used is controlled 1975 from the system / user's SASL configuration file for the 'qemu' 1976 service. This is typically found in /etc/sasl2/qemu.conf. If 1977 running QEMU as an unprivileged user, an environment variable 1978 SASL\_CONF\_PATH can be used to make it search alternate 1979 locations for the service config. While some SASL auth methods 1980 can also provide data encryption (eg GSSAPI), it is recommended 1981 that SASL always be combined with the 'tls' and 'x509' settings 1982 to enable use of SSL and server certificates. This ensures a 1983 data encryption preventing compromise of authentication 1984 credentials. 1985 1986 ``disable-ticketing=on|off`` 1987 Allow client connects without authentication. 1988 1989 ``disable-copy-paste=on|off`` 1990 Disable copy paste between the client and the guest. 1991 1992 ``disable-agent-file-xfer=on|off`` 1993 Disable spice-vdagent based file-xfer between the client and the 1994 guest. 1995 1996 ``tls-port=<nr>`` 1997 Set the TCP port spice is listening on for encrypted channels. 1998 1999 ``x509-dir=<dir>`` 2000 Set the x509 file directory. Expects same filenames as -vnc 2001 $display,x509=$dir 2002 2003 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2004 The x509 file names can also be configured individually. 2005 2006 ``tls-ciphers=<list>`` 2007 Specify which ciphers to use. 2008 2009 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2010 Force specific channel to be used with or without TLS 2011 encryption. The options can be specified multiple times to 2012 configure multiple channels. The special name "default" can be 2013 used to set the default mode. For channels which are not 2014 explicitly forced into one mode the spice client is allowed to 2015 pick tls/plaintext as he pleases. 2016 2017 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2018 Configure image compression (lossless). Default is auto\_glz. 2019 2020 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2021 Configure wan image compression (lossy for slow links). Default 2022 is auto. 2023 2024 ``streaming-video=[off|all|filter]`` 2025 Configure video stream detection. Default is off. 2026 2027 ``agent-mouse=[on|off]`` 2028 Enable/disable passing mouse events via vdagent. Default is on. 2029 2030 ``playback-compression=[on|off]`` 2031 Enable/disable audio stream compression (using celt 0.5.1). 2032 Default is on. 2033 2034 ``seamless-migration=[on|off]`` 2035 Enable/disable spice seamless migration. Default is off. 2036 2037 ``gl=[on|off]`` 2038 Enable/disable OpenGL context. Default is off. 2039 2040 ``rendernode=<file>`` 2041 DRM render node for OpenGL rendering. If not specified, it will 2042 pick the first available. (Since 2.9) 2043ERST 2044 2045DEF("portrait", 0, QEMU_OPTION_portrait, 2046 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2047 QEMU_ARCH_ALL) 2048SRST 2049``-portrait`` 2050 Rotate graphical output 90 deg left (only PXA LCD). 2051ERST 2052 2053DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2054 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2055 QEMU_ARCH_ALL) 2056SRST 2057``-rotate deg`` 2058 Rotate graphical output some deg left (only PXA LCD). 2059ERST 2060 2061DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2062 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2063 " select video card type\n", QEMU_ARCH_ALL) 2064SRST 2065``-vga type`` 2066 Select type of VGA card to emulate. Valid values for type are 2067 2068 ``cirrus`` 2069 Cirrus Logic GD5446 Video card. All Windows versions starting 2070 from Windows 95 should recognize and use this graphic card. For 2071 optimal performances, use 16 bit color depth in the guest and 2072 the host OS. (This card was the default before QEMU 2.2) 2073 2074 ``std`` 2075 Standard VGA card with Bochs VBE extensions. If your guest OS 2076 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2077 you want to use high resolution modes (>= 1280x1024x16) then you 2078 should use this option. (This card is the default since QEMU 2079 2.2) 2080 2081 ``vmware`` 2082 VMWare SVGA-II compatible adapter. Use it if you have 2083 sufficiently recent XFree86/XOrg server or Windows guest with a 2084 driver for this card. 2085 2086 ``qxl`` 2087 QXL paravirtual graphic card. It is VGA compatible (including 2088 VESA 2.0 VBE support). Works best with qxl guest drivers 2089 installed though. Recommended choice when using the spice 2090 protocol. 2091 2092 ``tcx`` 2093 (sun4m only) Sun TCX framebuffer. This is the default 2094 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2095 colour depths at a fixed resolution of 1024x768. 2096 2097 ``cg3`` 2098 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2099 framebuffer for sun4m machines available in both 1024x768 2100 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2101 wishing to run older Solaris versions. 2102 2103 ``virtio`` 2104 Virtio VGA card. 2105 2106 ``none`` 2107 Disable VGA card. 2108ERST 2109 2110DEF("full-screen", 0, QEMU_OPTION_full_screen, 2111 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2112SRST 2113``-full-screen`` 2114 Start in full screen. 2115ERST 2116 2117DEF("g", HAS_ARG, QEMU_OPTION_g , 2118 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2119 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2120SRST 2121``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2122 Set the initial graphical resolution and depth (PPC, SPARC only). 2123 2124 For PPC the default is 800x600x32. 2125 2126 For SPARC with the TCX graphics device, the default is 1024x768x8 2127 with the option of 1024x768x24. For cgthree, the default is 2128 1024x768x8 with the option of 1152x900x8 for people who wish to use 2129 OBP. 2130ERST 2131 2132DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2133 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2134SRST 2135``-vnc display[,option[,option[,...]]]`` 2136 Normally, if QEMU is compiled with graphical window support, it 2137 displays output such as guest graphics, guest console, and the QEMU 2138 monitor in a window. With this option, you can have QEMU listen on 2139 VNC display display and redirect the VGA display over the VNC 2140 session. It is very useful to enable the usb tablet device when 2141 using this option (option ``-device usb-tablet``). When using the 2142 VNC display, you must use the ``-k`` parameter to set the keyboard 2143 layout if you are not using en-us. Valid syntax for the display is 2144 2145 ``to=L`` 2146 With this option, QEMU will try next available VNC displays, 2147 until the number L, if the origianlly defined "-vnc display" is 2148 not available, e.g. port 5900+display is already used by another 2149 application. By default, to=0. 2150 2151 ``host:d`` 2152 TCP connections will only be allowed from host on display d. By 2153 convention the TCP port is 5900+d. Optionally, host can be 2154 omitted in which case the server will accept connections from 2155 any host. 2156 2157 ``unix:path`` 2158 Connections will be allowed over UNIX domain sockets where path 2159 is the location of a unix socket to listen for connections on. 2160 2161 ``none`` 2162 VNC is initialized but not started. The monitor ``change`` 2163 command can be used to later start the VNC server. 2164 2165 Following the display value there may be one or more option flags 2166 separated by commas. Valid options are 2167 2168 ``reverse=on|off`` 2169 Connect to a listening VNC client via a "reverse" connection. 2170 The client is specified by the display. For reverse network 2171 connections (host:d,``reverse``), the d argument is a TCP port 2172 number, not a display number. 2173 2174 ``websocket=on|off`` 2175 Opens an additional TCP listening port dedicated to VNC 2176 Websocket connections. If a bare websocket option is given, the 2177 Websocket port is 5700+display. An alternative port can be 2178 specified with the syntax ``websocket``\ =port. 2179 2180 If host is specified connections will only be allowed from this 2181 host. It is possible to control the websocket listen address 2182 independently, using the syntax ``websocket``\ =host:port. 2183 2184 If no TLS credentials are provided, the websocket connection 2185 runs in unencrypted mode. If TLS credentials are provided, the 2186 websocket connection requires encrypted client connections. 2187 2188 ``password=on|off`` 2189 Require that password based authentication is used for client 2190 connections. 2191 2192 The password must be set separately using the ``set_password`` 2193 command in the :ref:`QEMU monitor`. The 2194 syntax to change your password is: 2195 ``set_password <protocol> <password>`` where <protocol> could be 2196 either "vnc" or "spice". 2197 2198 If you would like to change <protocol> password expiration, you 2199 should use ``expire_password <protocol> <expiration-time>`` 2200 where expiration time could be one of the following options: 2201 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2202 make password expire in 60 seconds, or 1335196800 to make 2203 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2204 this date and time). 2205 2206 You can also use keywords "now" or "never" for the expiration 2207 time to allow <protocol> password to expire immediately or never 2208 expire. 2209 2210 ``password-secret=<secret-id>`` 2211 Require that password based authentication is used for client 2212 connections, using the password provided by the ``secret`` 2213 object identified by ``secret-id``. 2214 2215 ``tls-creds=ID`` 2216 Provides the ID of a set of TLS credentials to use to secure the 2217 VNC server. They will apply to both the normal VNC server socket 2218 and the websocket socket (if enabled). Setting TLS credentials 2219 will cause the VNC server socket to enable the VeNCrypt auth 2220 mechanism. The credentials should have been previously created 2221 using the ``-object tls-creds`` argument. 2222 2223 ``tls-authz=ID`` 2224 Provides the ID of the QAuthZ authorization object against which 2225 the client's x509 distinguished name will validated. This object 2226 is only resolved at time of use, so can be deleted and recreated 2227 on the fly while the VNC server is active. If missing, it will 2228 default to denying access. 2229 2230 ``sasl=on|off`` 2231 Require that the client use SASL to authenticate with the VNC 2232 server. The exact choice of authentication method used is 2233 controlled from the system / user's SASL configuration file for 2234 the 'qemu' service. This is typically found in 2235 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2236 an environment variable SASL\_CONF\_PATH can be used to make it 2237 search alternate locations for the service config. While some 2238 SASL auth methods can also provide data encryption (eg GSSAPI), 2239 it is recommended that SASL always be combined with the 'tls' 2240 and 'x509' settings to enable use of SSL and server 2241 certificates. This ensures a data encryption preventing 2242 compromise of authentication credentials. See the 2243 :ref:`VNC security` section in the System Emulation Users Guide 2244 for details on using SASL authentication. 2245 2246 ``sasl-authz=ID`` 2247 Provides the ID of the QAuthZ authorization object against which 2248 the client's SASL username will validated. This object is only 2249 resolved at time of use, so can be deleted and recreated on the 2250 fly while the VNC server is active. If missing, it will default 2251 to denying access. 2252 2253 ``acl=on|off`` 2254 Legacy method for enabling authorization of clients against the 2255 x509 distinguished name and SASL username. It results in the 2256 creation of two ``authz-list`` objects with IDs of 2257 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2258 objects must be configured with the HMP ACL commands. 2259 2260 This option is deprecated and should no longer be used. The new 2261 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2262 2263 ``lossy=on|off`` 2264 Enable lossy compression methods (gradient, JPEG, ...). If this 2265 option is set, VNC client may receive lossy framebuffer updates 2266 depending on its encoding settings. Enabling this option can 2267 save a lot of bandwidth at the expense of quality. 2268 2269 ``non-adaptive=on|off`` 2270 Disable adaptive encodings. Adaptive encodings are enabled by 2271 default. An adaptive encoding will try to detect frequently 2272 updated screen regions, and send updates in these regions using 2273 a lossy encoding (like JPEG). This can be really helpful to save 2274 bandwidth when playing videos. Disabling adaptive encodings 2275 restores the original static behavior of encodings like Tight. 2276 2277 ``share=[allow-exclusive|force-shared|ignore]`` 2278 Set display sharing policy. 'allow-exclusive' allows clients to 2279 ask for exclusive access. As suggested by the rfb spec this is 2280 implemented by dropping other connections. Connecting multiple 2281 clients in parallel requires all clients asking for a shared 2282 session (vncviewer: -shared switch). This is the default. 2283 'force-shared' disables exclusive client access. Useful for 2284 shared desktop sessions, where you don't want someone forgetting 2285 specify -shared disconnect everybody else. 'ignore' completely 2286 ignores the shared flag and allows everybody connect 2287 unconditionally. Doesn't conform to the rfb spec but is 2288 traditional QEMU behavior. 2289 2290 ``key-delay-ms`` 2291 Set keyboard delay, for key down and key up events, in 2292 milliseconds. Default is 10. Keyboards are low-bandwidth 2293 devices, so this slowdown can help the device and guest to keep 2294 up and not lose events in case events are arriving in bulk. 2295 Possible causes for the latter are flaky network connections, or 2296 scripts for automated testing. 2297 2298 ``audiodev=audiodev`` 2299 Use the specified audiodev when the VNC client requests audio 2300 transmission. When not using an -audiodev argument, this option 2301 must be omitted, otherwise is must be present and specify a 2302 valid audiodev. 2303 2304 ``power-control=on|off`` 2305 Permit the remote client to issue shutdown, reboot or reset power 2306 control requests. 2307ERST 2308 2309ARCHHEADING(, QEMU_ARCH_I386) 2310 2311ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2312 2313DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2314 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2315 QEMU_ARCH_I386) 2316SRST 2317``-win2k-hack`` 2318 Use it when installing Windows 2000 to avoid a disk full bug. After 2319 Windows 2000 is installed, you no longer need this option (this 2320 option slows down the IDE transfers). 2321ERST 2322 2323DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2324 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2325 QEMU_ARCH_I386) 2326SRST 2327``-no-fd-bootchk`` 2328 Disable boot signature checking for floppy disks in BIOS. May be 2329 needed to boot from old floppy disks. 2330ERST 2331 2332DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2333 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2334SRST 2335``-no-acpi`` 2336 Disable ACPI (Advanced Configuration and Power Interface) support. 2337 Use it if your guest OS complains about ACPI problems (PC target 2338 machine only). 2339ERST 2340 2341DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2342 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2343SRST 2344``-no-hpet`` 2345 Disable HPET support. 2346ERST 2347 2348DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2349 "-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" 2350 " ACPI table description\n", QEMU_ARCH_I386) 2351SRST 2352``-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]...]`` 2353 Add ACPI table with specified header fields and context from 2354 specified files. For file=, take whole ACPI table from the specified 2355 files, including all ACPI headers (possible overridden by other 2356 options). For data=, only data portion of the table is used, all 2357 header information is specified in the command line. If a SLIC table 2358 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2359 fields will override the same in the RSDT and the FADT (a.k.a. 2360 FACP), in order to ensure the field matches required by the 2361 Microsoft SLIC spec and the ACPI spec. 2362ERST 2363 2364DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2365 "-smbios file=binary\n" 2366 " load SMBIOS entry from binary file\n" 2367 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2368 " [,uefi=on|off]\n" 2369 " specify SMBIOS type 0 fields\n" 2370 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2371 " [,uuid=uuid][,sku=str][,family=str]\n" 2372 " specify SMBIOS type 1 fields\n" 2373 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2374 " [,asset=str][,location=str]\n" 2375 " specify SMBIOS type 2 fields\n" 2376 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2377 " [,sku=str]\n" 2378 " specify SMBIOS type 3 fields\n" 2379 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2380 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2381 " specify SMBIOS type 4 fields\n" 2382 "-smbios type=11[,value=str][,path=filename]\n" 2383 " specify SMBIOS type 11 fields\n" 2384 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2385 " [,asset=str][,part=str][,speed=%d]\n" 2386 " specify SMBIOS type 17 fields\n" 2387 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2388 " specify SMBIOS type 41 fields\n", 2389 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2390SRST 2391``-smbios file=binary`` 2392 Load SMBIOS entry from binary file. 2393 2394``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2395 Specify SMBIOS type 0 fields 2396 2397``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2398 Specify SMBIOS type 1 fields 2399 2400``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2401 Specify SMBIOS type 2 fields 2402 2403``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2404 Specify SMBIOS type 3 fields 2405 2406``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2407 Specify SMBIOS type 4 fields 2408 2409``-smbios type=11[,value=str][,path=filename]`` 2410 Specify SMBIOS type 11 fields 2411 2412 This argument can be repeated multiple times, and values are added in the order they are parsed. 2413 Applications intending to use OEM strings data are encouraged to use their application name as 2414 a prefix for the value string. This facilitates passing information for multiple applications 2415 concurrently. 2416 2417 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2418 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2419 2420 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2421 the SMBIOS table in the order in which they appear. 2422 2423 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2424 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2425 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2426 data set, for example, by specifying the serial ID of a block device. 2427 2428 An example passing three strings is 2429 2430 .. parsed-literal:: 2431 2432 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2433 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2434 path=/some/file/with/oemstringsdata.txt 2435 2436 In the guest OS this is visible with the ``dmidecode`` command 2437 2438 .. parsed-literal:: 2439 2440 $ dmidecode -t 11 2441 Handle 0x0E00, DMI type 11, 5 bytes 2442 OEM Strings 2443 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2444 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2445 String 3: myapp:some extra data 2446 2447 2448``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2449 Specify SMBIOS type 17 fields 2450 2451``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2452 Specify SMBIOS type 41 fields 2453 2454 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2455 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2456 position on the PCI bus. 2457 2458 Here is an example of use: 2459 2460 .. parsed-literal:: 2461 2462 -netdev user,id=internet \\ 2463 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2464 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2465 2466 In the guest OS, the device should then appear as ``eno1``: 2467 2468 ..parsed-literal:: 2469 2470 $ ip -brief l 2471 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2472 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2473 2474 Currently, the PCI device has to be attached to the root bus. 2475 2476ERST 2477 2478DEFHEADING() 2479 2480DEFHEADING(Network options:) 2481 2482DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2483#ifdef CONFIG_SLIRP 2484 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2485 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2486 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2487 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2488 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2489#ifndef _WIN32 2490 "[,smb=dir[,smbserver=addr]]\n" 2491#endif 2492 " configure a user mode network backend with ID 'str',\n" 2493 " its DHCP server and optional services\n" 2494#endif 2495#ifdef _WIN32 2496 "-netdev tap,id=str,ifname=name\n" 2497 " configure a host TAP network backend with ID 'str'\n" 2498#else 2499 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2500 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2501 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2502 " [,poll-us=n]\n" 2503 " configure a host TAP network backend with ID 'str'\n" 2504 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2505 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2506 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2507 " to deconfigure it\n" 2508 " use '[down]script=no' to disable script execution\n" 2509 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2510 " configure it\n" 2511 " use 'fd=h' to connect to an already opened TAP interface\n" 2512 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2513 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2514 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2515 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2516 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2517 " use vhost=on to enable experimental in kernel accelerator\n" 2518 " (only has effect for virtio guests which use MSIX)\n" 2519 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2520 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2521 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2522 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2523 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2524 " spent on busy polling for vhost net\n" 2525 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2526 " configure a host TAP network backend with ID 'str' that is\n" 2527 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2528 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2529#endif 2530#ifdef __linux__ 2531 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2532 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2533 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2534 " [,rxcookie=rxcookie][,offset=offset]\n" 2535 " configure a network backend with ID 'str' connected to\n" 2536 " an Ethernet over L2TPv3 pseudowire.\n" 2537 " Linux kernel 3.3+ as well as most routers can talk\n" 2538 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2539 " VM to a router and even VM to Host. It is a nearly-universal\n" 2540 " standard (RFC3931). Note - this implementation uses static\n" 2541 " pre-configured tunnels (same as the Linux kernel).\n" 2542 " use 'src=' to specify source address\n" 2543 " use 'dst=' to specify destination address\n" 2544 " use 'udp=on' to specify udp encapsulation\n" 2545 " use 'srcport=' to specify source udp port\n" 2546 " use 'dstport=' to specify destination udp port\n" 2547 " use 'ipv6=on' to force v6\n" 2548 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2549 " well as a weak security measure\n" 2550 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2551 " use 'txcookie=0x012345678' to specify a txcookie\n" 2552 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2553 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2554 " use 'pincounter=on' to work around broken counter handling in peer\n" 2555 " use 'offset=X' to add an extra offset between header and data\n" 2556#endif 2557 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2558 " configure a network backend to connect to another network\n" 2559 " using a socket connection\n" 2560 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2561 " configure a network backend to connect to a multicast maddr and port\n" 2562 " use 'localaddr=addr' to specify the host address to send packets from\n" 2563 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2564 " configure a network backend to connect to another network\n" 2565 " using an UDP tunnel\n" 2566#ifdef CONFIG_VDE 2567 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2568 " configure a network backend to connect to port 'n' of a vde switch\n" 2569 " running on host and listening for incoming connections on 'socketpath'.\n" 2570 " Use group 'groupname' and mode 'octalmode' to change default\n" 2571 " ownership and permissions for communication port.\n" 2572#endif 2573#ifdef CONFIG_NETMAP 2574 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2575 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2576 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2577 " netmap device, defaults to '/dev/netmap')\n" 2578#endif 2579#ifdef CONFIG_POSIX 2580 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2581 " configure a vhost-user network, backed by a chardev 'dev'\n" 2582#endif 2583#ifdef __linux__ 2584 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2585 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2586#endif 2587 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2588 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2589DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2590 "-nic [tap|bridge|" 2591#ifdef CONFIG_SLIRP 2592 "user|" 2593#endif 2594#ifdef __linux__ 2595 "l2tpv3|" 2596#endif 2597#ifdef CONFIG_VDE 2598 "vde|" 2599#endif 2600#ifdef CONFIG_NETMAP 2601 "netmap|" 2602#endif 2603#ifdef CONFIG_POSIX 2604 "vhost-user|" 2605#endif 2606 "socket][,option][,...][mac=macaddr]\n" 2607 " initialize an on-board / default host NIC (using MAC address\n" 2608 " macaddr) and connect it to the given host network backend\n" 2609 "-nic none use it alone to have zero network devices (the default is to\n" 2610 " provided a 'user' network connection)\n", 2611 QEMU_ARCH_ALL) 2612DEF("net", HAS_ARG, QEMU_OPTION_net, 2613 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2614 " configure or create an on-board (or machine default) NIC and\n" 2615 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2616 "-net [" 2617#ifdef CONFIG_SLIRP 2618 "user|" 2619#endif 2620 "tap|" 2621 "bridge|" 2622#ifdef CONFIG_VDE 2623 "vde|" 2624#endif 2625#ifdef CONFIG_NETMAP 2626 "netmap|" 2627#endif 2628 "socket][,option][,option][,...]\n" 2629 " old way to initialize a host network interface\n" 2630 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2631SRST 2632``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2633 This option is a shortcut for configuring both the on-board 2634 (default) guest NIC hardware and the host network backend in one go. 2635 The host backend options are the same as with the corresponding 2636 ``-netdev`` options below. The guest NIC model can be set with 2637 ``model=modelname``. Use ``model=help`` to list the available device 2638 types. The hardware MAC address can be set with ``mac=macaddr``. 2639 2640 The following two example do exactly the same, to show how ``-nic`` 2641 can be used to shorten the command line length: 2642 2643 .. parsed-literal:: 2644 2645 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2646 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2647 2648``-nic none`` 2649 Indicate that no network devices should be configured. It is used to 2650 override the default configuration (default NIC with "user" host 2651 network backend) which is activated if no other networking options 2652 are provided. 2653 2654``-netdev user,id=id[,option][,option][,...]`` 2655 Configure user mode host network backend which requires no 2656 administrator privilege to run. Valid options are: 2657 2658 ``id=id`` 2659 Assign symbolic name for use in monitor commands. 2660 2661 ``ipv4=on|off and ipv6=on|off`` 2662 Specify that either IPv4 or IPv6 must be enabled. If neither is 2663 specified both protocols are enabled. 2664 2665 ``net=addr[/mask]`` 2666 Set IP network address the guest will see. Optionally specify 2667 the netmask, either in the form a.b.c.d or as number of valid 2668 top-most bits. Default is 10.0.2.0/24. 2669 2670 ``host=addr`` 2671 Specify the guest-visible address of the host. Default is the 2672 2nd IP in the guest network, i.e. x.x.x.2. 2673 2674 ``ipv6-net=addr[/int]`` 2675 Set IPv6 network address the guest will see (default is 2676 fec0::/64). The network prefix is given in the usual hexadecimal 2677 IPv6 address notation. The prefix size is optional, and is given 2678 as the number of valid top-most bits (default is 64). 2679 2680 ``ipv6-host=addr`` 2681 Specify the guest-visible IPv6 address of the host. Default is 2682 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2683 2684 ``restrict=on|off`` 2685 If this option is enabled, the guest will be isolated, i.e. it 2686 will not be able to contact the host and no guest IP packets 2687 will be routed over the host to the outside. This option does 2688 not affect any explicitly set forwarding rules. 2689 2690 ``hostname=name`` 2691 Specifies the client hostname reported by the built-in DHCP 2692 server. 2693 2694 ``dhcpstart=addr`` 2695 Specify the first of the 16 IPs the built-in DHCP server can 2696 assign. Default is the 15th to 31st IP in the guest network, 2697 i.e. x.x.x.15 to x.x.x.31. 2698 2699 ``dns=addr`` 2700 Specify the guest-visible address of the virtual nameserver. The 2701 address must be different from the host address. Default is the 2702 3rd IP in the guest network, i.e. x.x.x.3. 2703 2704 ``ipv6-dns=addr`` 2705 Specify the guest-visible address of the IPv6 virtual 2706 nameserver. The address must be different from the host address. 2707 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2708 2709 ``dnssearch=domain`` 2710 Provides an entry for the domain-search list sent by the 2711 built-in DHCP server. More than one domain suffix can be 2712 transmitted by specifying this option multiple times. If 2713 supported, this will cause the guest to automatically try to 2714 append the given domain suffix(es) in case a domain name can not 2715 be resolved. 2716 2717 Example: 2718 2719 .. parsed-literal:: 2720 2721 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2722 2723 ``domainname=domain`` 2724 Specifies the client domain name reported by the built-in DHCP 2725 server. 2726 2727 ``tftp=dir`` 2728 When using the user mode network stack, activate a built-in TFTP 2729 server. The files in dir will be exposed as the root of a TFTP 2730 server. The TFTP client on the guest must be configured in 2731 binary mode (use the command ``bin`` of the Unix TFTP client). 2732 2733 ``tftp-server-name=name`` 2734 In BOOTP reply, broadcast name as the "TFTP server name" 2735 (RFC2132 option 66). This can be used to advise the guest to 2736 load boot files or configurations from a different server than 2737 the host address. 2738 2739 ``bootfile=file`` 2740 When using the user mode network stack, broadcast file as the 2741 BOOTP filename. In conjunction with ``tftp``, this can be used 2742 to network boot a guest from a local directory. 2743 2744 Example (using pxelinux): 2745 2746 .. parsed-literal:: 2747 2748 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2749 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2750 2751 ``smb=dir[,smbserver=addr]`` 2752 When using the user mode network stack, activate a built-in SMB 2753 server so that Windows OSes can access to the host files in 2754 ``dir`` transparently. The IP address of the SMB server can be 2755 set to addr. By default the 4th IP in the guest network is used, 2756 i.e. x.x.x.4. 2757 2758 In the guest Windows OS, the line: 2759 2760 :: 2761 2762 10.0.2.4 smbserver 2763 2764 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2765 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2766 NT/2000). 2767 2768 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2769 2770 Note that a SAMBA server must be installed on the host OS. 2771 2772 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2773 Redirect incoming TCP or UDP connections to the host port 2774 hostport to the guest IP address guestaddr on guest port 2775 guestport. If guestaddr is not specified, its value is x.x.x.15 2776 (default first address given by the built-in DHCP server). By 2777 specifying hostaddr, the rule can be bound to a specific host 2778 interface. If no connection type is set, TCP is used. This 2779 option can be given multiple times. 2780 2781 For example, to redirect host X11 connection from screen 1 to 2782 guest screen 0, use the following: 2783 2784 .. parsed-literal:: 2785 2786 # on the host 2787 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2788 # this host xterm should open in the guest X11 server 2789 xterm -display :1 2790 2791 To redirect telnet connections from host port 5555 to telnet 2792 port on the guest, use the following: 2793 2794 .. parsed-literal:: 2795 2796 # on the host 2797 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2798 telnet localhost 5555 2799 2800 Then when you use on the host ``telnet localhost 5555``, you 2801 connect to the guest telnet server. 2802 2803 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2804 Forward guest TCP connections to the IP address server on port 2805 port to the character device dev or to a program executed by 2806 cmd:command which gets spawned for each connection. This option 2807 can be given multiple times. 2808 2809 You can either use a chardev directly and have that one used 2810 throughout QEMU's lifetime, like in the following example: 2811 2812 .. parsed-literal:: 2813 2814 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2815 # the guest accesses it 2816 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2817 2818 Or you can execute a command on every TCP connection established 2819 by the guest, so that QEMU behaves similar to an inetd process 2820 for that virtual server: 2821 2822 .. parsed-literal:: 2823 2824 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2825 # and connect the TCP stream to its stdin/stdout 2826 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2827 2828``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2829 Configure a host TAP network backend with ID id. 2830 2831 Use the network script file to configure it and the network script 2832 dfile to deconfigure it. If name is not provided, the OS 2833 automatically provides one. The default network configure script is 2834 ``/etc/qemu-ifup`` and the default network deconfigure script is 2835 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2836 disable script execution. 2837 2838 If running QEMU as an unprivileged user, use the network helper 2839 to configure the TAP interface and attach it to the bridge. 2840 The default network helper executable is 2841 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2842 ``br0``. 2843 2844 ``fd``\ =h can be used to specify the handle of an already opened 2845 host TAP interface. 2846 2847 Examples: 2848 2849 .. parsed-literal:: 2850 2851 #launch a QEMU instance with the default network script 2852 |qemu_system| linux.img -nic tap 2853 2854 .. parsed-literal:: 2855 2856 #launch a QEMU instance with two NICs, each one connected 2857 #to a TAP device 2858 |qemu_system| linux.img \\ 2859 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2860 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2861 2862 .. parsed-literal:: 2863 2864 #launch a QEMU instance with the default network helper to 2865 #connect a TAP device to bridge br0 2866 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2867 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2868 2869``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2870 Connect a host TAP network interface to a host bridge device. 2871 2872 Use the network helper helper to configure the TAP interface and 2873 attach it to the bridge. The default network helper executable is 2874 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2875 ``br0``. 2876 2877 Examples: 2878 2879 .. parsed-literal:: 2880 2881 #launch a QEMU instance with the default network helper to 2882 #connect a TAP device to bridge br0 2883 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2884 2885 .. parsed-literal:: 2886 2887 #launch a QEMU instance with the default network helper to 2888 #connect a TAP device to bridge qemubr0 2889 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2890 2891``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2892 This host network backend can be used to connect the guest's network 2893 to another QEMU virtual machine using a TCP socket connection. If 2894 ``listen`` is specified, QEMU waits for incoming connections on port 2895 (host is optional). ``connect`` is used to connect to another QEMU 2896 instance using the ``listen`` option. ``fd``\ =h specifies an 2897 already opened TCP socket. 2898 2899 Example: 2900 2901 .. parsed-literal:: 2902 2903 # launch a first QEMU instance 2904 |qemu_system| linux.img \\ 2905 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2906 -netdev socket,id=n1,listen=:1234 2907 # connect the network of this instance to the network of the first instance 2908 |qemu_system| linux.img \\ 2909 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2910 -netdev socket,id=n2,connect=127.0.0.1:1234 2911 2912``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2913 Configure a socket host network backend to share the guest's network 2914 traffic with another QEMU virtual machines using a UDP multicast 2915 socket, effectively making a bus for every QEMU with same multicast 2916 address maddr and port. NOTES: 2917 2918 1. Several QEMU can be running on different hosts and share same bus 2919 (assuming correct multicast setup for these hosts). 2920 2921 2. mcast support is compatible with User Mode Linux (argument 2922 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2923 2924 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2925 2926 Example: 2927 2928 .. parsed-literal:: 2929 2930 # launch one QEMU instance 2931 |qemu_system| linux.img \\ 2932 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2933 -netdev socket,id=n1,mcast=230.0.0.1:1234 2934 # launch another QEMU instance on same "bus" 2935 |qemu_system| linux.img \\ 2936 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2937 -netdev socket,id=n2,mcast=230.0.0.1:1234 2938 # launch yet another QEMU instance on same "bus" 2939 |qemu_system| linux.img \\ 2940 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2941 -netdev socket,id=n3,mcast=230.0.0.1:1234 2942 2943 Example (User Mode Linux compat.): 2944 2945 .. parsed-literal:: 2946 2947 # launch QEMU instance (note mcast address selected is UML's default) 2948 |qemu_system| linux.img \\ 2949 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2950 -netdev socket,id=n1,mcast=239.192.168.1:1102 2951 # launch UML 2952 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2953 2954 Example (send packets from host's 1.2.3.4): 2955 2956 .. parsed-literal:: 2957 2958 |qemu_system| linux.img \\ 2959 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2960 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2961 2962``-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]`` 2963 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2964 is a popular protocol to transport Ethernet (and other Layer 2) data 2965 frames between two systems. It is present in routers, firewalls and 2966 the Linux kernel (from version 3.3 onwards). 2967 2968 This transport allows a VM to communicate to another VM, router or 2969 firewall directly. 2970 2971 ``src=srcaddr`` 2972 source address (mandatory) 2973 2974 ``dst=dstaddr`` 2975 destination address (mandatory) 2976 2977 ``udp`` 2978 select udp encapsulation (default is ip). 2979 2980 ``srcport=srcport`` 2981 source udp port. 2982 2983 ``dstport=dstport`` 2984 destination udp port. 2985 2986 ``ipv6`` 2987 force v6, otherwise defaults to v4. 2988 2989 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2990 Cookies are a weak form of security in the l2tpv3 specification. 2991 Their function is mostly to prevent misconfiguration. By default 2992 they are 32 bit. 2993 2994 ``cookie64`` 2995 Set cookie size to 64 bit instead of the default 32 2996 2997 ``counter=off`` 2998 Force a 'cut-down' L2TPv3 with no counter as in 2999 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3000 3001 ``pincounter=on`` 3002 Work around broken counter handling in peer. This may also help 3003 on networks which have packet reorder. 3004 3005 ``offset=offset`` 3006 Add an extra offset between header and data 3007 3008 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3009 the bridge br-lan on the remote Linux host 1.2.3.4: 3010 3011 .. parsed-literal:: 3012 3013 # Setup tunnel on linux host using raw ip as encapsulation 3014 # on 1.2.3.4 3015 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3016 encap udp udp_sport 16384 udp_dport 16384 3017 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3018 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3019 ifconfig vmtunnel0 mtu 1500 3020 ifconfig vmtunnel0 up 3021 brctl addif br-lan vmtunnel0 3022 3023 3024 # on 4.3.2.1 3025 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3026 3027 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3028 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3029 3030``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3031 Configure VDE backend to connect to PORT n of a vde switch running 3032 on host and listening for incoming connections on socketpath. Use 3033 GROUP groupname and MODE octalmode to change default ownership and 3034 permissions for communication port. This option is only available if 3035 QEMU has been compiled with vde support enabled. 3036 3037 Example: 3038 3039 .. parsed-literal:: 3040 3041 # launch vde switch 3042 vde_switch -F -sock /tmp/myswitch 3043 # launch QEMU instance 3044 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3045 3046``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3047 Establish a vhost-user netdev, backed by a chardev id. The chardev 3048 should be a unix domain socket backed one. The vhost-user uses a 3049 specifically defined protocol to pass vhost ioctl replacement 3050 messages to an application on the other end of the socket. On 3051 non-MSIX guests, the feature can be forced with vhostforce. Use 3052 'queues=n' to specify the number of queues to be created for 3053 multiqueue vhost-user. 3054 3055 Example: 3056 3057 :: 3058 3059 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3060 -numa node,memdev=mem \ 3061 -chardev socket,id=chr0,path=/path/to/socket \ 3062 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3063 -device virtio-net-pci,netdev=net0 3064 3065``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3066 Establish a vhost-vdpa netdev. 3067 3068 vDPA device is a device that uses a datapath which complies with 3069 the virtio specifications with a vendor specific control path. 3070 vDPA devices can be both physically located on the hardware or 3071 emulated by software. 3072 3073``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3074 Create a hub port on the emulated hub with ID hubid. 3075 3076 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3077 instead of a single netdev. Alternatively, you can also connect the 3078 hubport to another netdev with ID nd by using the ``netdev=nd`` 3079 option. 3080 3081``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3082 Legacy option to configure or create an on-board (or machine 3083 default) Network Interface Card(NIC) and connect it either to the 3084 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3085 If model is omitted, then the default NIC model associated with the 3086 machine type is used. Note that the default NIC model may change in 3087 future QEMU releases, so it is highly recommended to always specify 3088 a model. Optionally, the MAC address can be changed to mac, the 3089 device address set to addr (PCI cards only), and a name can be 3090 assigned for use in monitor commands. Optionally, for PCI cards, you 3091 can specify the number v of MSI-X vectors that the card should have; 3092 this option currently only affects virtio cards; set v = 0 to 3093 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3094 created. QEMU can emulate several different models of network card. 3095 Use ``-net nic,model=help`` for a list of available devices for your 3096 target. 3097 3098``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3099 Configure a host network backend (with the options corresponding to 3100 the same ``-netdev`` option) and connect it to the emulated hub 0 3101 (the default hub). Use name to specify the name of the hub port. 3102ERST 3103 3104DEFHEADING() 3105 3106DEFHEADING(Character device options:) 3107 3108DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3109 "-chardev help\n" 3110 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3111 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3112 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3113 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3114 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3115 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3116 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3117 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3118 " [,logfile=PATH][,logappend=on|off]\n" 3119 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3120 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3121 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3122 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3123 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3124 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3125#ifdef _WIN32 3126 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3127 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3128#else 3129 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3130 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3131#endif 3132#ifdef CONFIG_BRLAPI 3133 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3134#endif 3135#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3136 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3137 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3138 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3139#endif 3140#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3141 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3142 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3143#endif 3144#if defined(CONFIG_SPICE) 3145 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3146 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3147#endif 3148 , QEMU_ARCH_ALL 3149) 3150 3151SRST 3152The general form of a character device option is: 3153 3154``-chardev backend,id=id[,mux=on|off][,options]`` 3155 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3156 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3157 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3158 ``spicevmc``, ``spiceport``. The specific backend will determine the 3159 applicable options. 3160 3161 Use ``-chardev help`` to print all available chardev backend types. 3162 3163 All devices must have an id, which can be any string up to 127 3164 characters long. It is used to uniquely identify this device in 3165 other command line directives. 3166 3167 A character device may be used in multiplexing mode by multiple 3168 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3169 a "1:N" device, and here the "1" end is your specified chardev 3170 backend, and the "N" end is the various parts of QEMU that can talk 3171 to a chardev. If you create a chardev with ``id=myid`` and 3172 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3173 and you can then configure multiple front ends to use that chardev 3174 ID for their input/output. Up to four different front ends can be 3175 connected to a single multiplexed chardev. (Without multiplexing 3176 enabled, a chardev can only be used by a single front end.) For 3177 instance you could use this to allow a single stdio chardev to be 3178 used by two serial ports and the QEMU monitor: 3179 3180 :: 3181 3182 -chardev stdio,mux=on,id=char0 \ 3183 -mon chardev=char0,mode=readline \ 3184 -serial chardev:char0 \ 3185 -serial chardev:char0 3186 3187 You can have more than one multiplexer in a system configuration; 3188 for instance you could have a TCP port multiplexed between UART 0 3189 and UART 1, and stdio multiplexed between the QEMU monitor and a 3190 parallel port: 3191 3192 :: 3193 3194 -chardev stdio,mux=on,id=char0 \ 3195 -mon chardev=char0,mode=readline \ 3196 -parallel chardev:char0 \ 3197 -chardev tcp,...,mux=on,id=char1 \ 3198 -serial chardev:char1 \ 3199 -serial chardev:char1 3200 3201 When you're using a multiplexed character device, some escape 3202 sequences are interpreted in the input. See the chapter about 3203 :ref:`keys in the character backend multiplexer` in the 3204 System Emulation Users Guide for more details. 3205 3206 Note that some other command line options may implicitly create 3207 multiplexed character backends; for instance ``-serial mon:stdio`` 3208 creates a multiplexed stdio backend connected to the serial port and 3209 the QEMU monitor, and ``-nographic`` also multiplexes the console 3210 and the monitor to stdio. 3211 3212 There is currently no support for multiplexing in the other 3213 direction (where a single QEMU front end takes input and output from 3214 multiple chardevs). 3215 3216 Every backend supports the ``logfile`` option, which supplies the 3217 path to a file to record all data transmitted via the backend. The 3218 ``logappend`` option controls whether the log file will be truncated 3219 or appended to when opened. 3220 3221The available backends are: 3222 3223``-chardev null,id=id`` 3224 A void device. This device will not emit any data, and will drop any 3225 data it receives. The null backend does not take any options. 3226 3227``-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]`` 3228 Create a two-way stream socket, which can be either a TCP or a unix 3229 socket. A unix socket will be created if ``path`` is specified. 3230 Behaviour is undefined if TCP options are specified for a unix 3231 socket. 3232 3233 ``server=on|off`` specifies that the socket shall be a listening socket. 3234 3235 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3236 to connect to a listening socket. 3237 3238 ``telnet=on|off`` specifies that traffic on the socket should interpret 3239 telnet escape sequences. 3240 3241 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3242 communication. 3243 3244 ``reconnect`` sets the timeout for reconnecting on non-server 3245 sockets when the remote end goes away. qemu will delay this many 3246 seconds and then attempt to reconnect. Zero disables reconnecting, 3247 and is the default. 3248 3249 ``tls-creds`` requests enablement of the TLS protocol for 3250 encryption, and specifies the id of the TLS credentials to use for 3251 the handshake. The credentials must be previously created with the 3252 ``-object tls-creds`` argument. 3253 3254 ``tls-auth`` provides the ID of the QAuthZ authorization object 3255 against which the client's x509 distinguished name will be 3256 validated. This object is only resolved at time of use, so can be 3257 deleted and recreated on the fly while the chardev server is active. 3258 If missing, it will default to denying access. 3259 3260 TCP and unix socket options are given below: 3261 3262 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3263 ``host`` for a listening socket specifies the local address to 3264 be bound. For a connecting socket species the remote host to 3265 connect to. ``host`` is optional for listening sockets. If not 3266 specified it defaults to ``0.0.0.0``. 3267 3268 ``port`` for a listening socket specifies the local port to be 3269 bound. For a connecting socket specifies the port on the remote 3270 host to connect to. ``port`` can be given as either a port 3271 number or a service name. ``port`` is required. 3272 3273 ``to`` is only relevant to listening sockets. If it is 3274 specified, and ``port`` cannot be bound, QEMU will attempt to 3275 bind to subsequent ports up to and including ``to`` until it 3276 succeeds. ``to`` must be specified as a port number. 3277 3278 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3279 or IPv6 must be used. If neither is specified the socket may 3280 use either protocol. 3281 3282 ``nodelay=on|off`` disables the Nagle algorithm. 3283 3284 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3285 ``path`` specifies the local path of the unix socket. ``path`` 3286 is required. 3287 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3288 rather than the filesystem. Optional, defaults to false. 3289 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3290 rather than the full sun_path length. Optional, defaults to true. 3291 3292``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3293 Sends all traffic from the guest to a remote host over UDP. 3294 3295 ``host`` specifies the remote host to connect to. If not specified 3296 it defaults to ``localhost``. 3297 3298 ``port`` specifies the port on the remote host to connect to. 3299 ``port`` is required. 3300 3301 ``localaddr`` specifies the local address to bind to. If not 3302 specified it defaults to ``0.0.0.0``. 3303 3304 ``localport`` specifies the local port to bind to. If not specified 3305 any available local port will be used. 3306 3307 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3308 If neither is specified the device may use either protocol. 3309 3310``-chardev msmouse,id=id`` 3311 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3312 does not take any options. 3313 3314``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3315 Connect to a QEMU text console. ``vc`` may optionally be given a 3316 specific size. 3317 3318 ``width`` and ``height`` specify the width and height respectively 3319 of the console, in pixels. 3320 3321 ``cols`` and ``rows`` specify that the console be sized to fit a 3322 text console with the given dimensions. 3323 3324``-chardev ringbuf,id=id[,size=size]`` 3325 Create a ring buffer with fixed size ``size``. size must be a power 3326 of two and defaults to ``64K``. 3327 3328``-chardev file,id=id,path=path`` 3329 Log all traffic received from the guest to a file. 3330 3331 ``path`` specifies the path of the file to be opened. This file will 3332 be created if it does not already exist, and overwritten if it does. 3333 ``path`` is required. 3334 3335``-chardev pipe,id=id,path=path`` 3336 Create a two-way connection to the guest. The behaviour differs 3337 slightly between Windows hosts and other hosts: 3338 3339 On Windows, a single duplex pipe will be created at 3340 ``\\.pipe\path``. 3341 3342 On other hosts, 2 pipes will be created called ``path.in`` and 3343 ``path.out``. Data written to ``path.in`` will be received by the 3344 guest. Data written by the guest can be read from ``path.out``. QEMU 3345 will not create these fifos, and requires them to be present. 3346 3347 ``path`` forms part of the pipe path as described above. ``path`` is 3348 required. 3349 3350``-chardev console,id=id`` 3351 Send traffic from the guest to QEMU's standard output. ``console`` 3352 does not take any options. 3353 3354 ``console`` is only available on Windows hosts. 3355 3356``-chardev serial,id=id,path=path`` 3357 Send traffic from the guest to a serial device on the host. 3358 3359 On Unix hosts serial will actually accept any tty device, not only 3360 serial lines. 3361 3362 ``path`` specifies the name of the serial device to open. 3363 3364``-chardev pty,id=id`` 3365 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3366 does not take any options. 3367 3368 ``pty`` is not available on Windows hosts. 3369 3370``-chardev stdio,id=id[,signal=on|off]`` 3371 Connect to standard input and standard output of the QEMU process. 3372 3373 ``signal`` controls if signals are enabled on the terminal, that 3374 includes exiting QEMU with the key sequence Control-c. This option 3375 is enabled by default, use ``signal=off`` to disable it. 3376 3377``-chardev braille,id=id`` 3378 Connect to a local BrlAPI server. ``braille`` does not take any 3379 options. 3380 3381``-chardev tty,id=id,path=path`` 3382 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3383 and DragonFlyBSD hosts. It is an alias for ``serial``. 3384 3385 ``path`` specifies the path to the tty. ``path`` is required. 3386 3387``-chardev parallel,id=id,path=path`` 3388 \ 3389``-chardev parport,id=id,path=path`` 3390 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3391 hosts. 3392 3393 Connect to a local parallel port. 3394 3395 ``path`` specifies the path to the parallel port device. ``path`` is 3396 required. 3397 3398``-chardev spicevmc,id=id,debug=debug,name=name`` 3399 ``spicevmc`` is only available when spice support is built in. 3400 3401 ``debug`` debug level for spicevmc 3402 3403 ``name`` name of spice channel to connect to 3404 3405 Connect to a spice virtual machine channel, such as vdiport. 3406 3407``-chardev spiceport,id=id,debug=debug,name=name`` 3408 ``spiceport`` is only available when spice support is built in. 3409 3410 ``debug`` debug level for spicevmc 3411 3412 ``name`` name of spice port to connect to 3413 3414 Connect to a spice port, allowing a Spice client to handle the 3415 traffic identified by a name (preferably a fqdn). 3416ERST 3417 3418DEFHEADING() 3419 3420#ifdef CONFIG_TPM 3421DEFHEADING(TPM device options:) 3422 3423DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3424 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3425 " use path to provide path to a character device; default is /dev/tpm0\n" 3426 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3427 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3428 "-tpmdev emulator,id=id,chardev=dev\n" 3429 " configure the TPM device using chardev backend\n", 3430 QEMU_ARCH_ALL) 3431SRST 3432The general form of a TPM device option is: 3433 3434``-tpmdev backend,id=id[,options]`` 3435 The specific backend type will determine the applicable options. The 3436 ``-tpmdev`` option creates the TPM backend and requires a 3437 ``-device`` option that specifies the TPM frontend interface model. 3438 3439 Use ``-tpmdev help`` to print all available TPM backend types. 3440 3441The available backends are: 3442 3443``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3444 (Linux-host only) Enable access to the host's TPM using the 3445 passthrough driver. 3446 3447 ``path`` specifies the path to the host's TPM device, i.e., on a 3448 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3449 default ``/dev/tpm0`` is used. 3450 3451 ``cancel-path`` specifies the path to the host TPM device's sysfs 3452 entry allowing for cancellation of an ongoing TPM command. 3453 ``cancel-path`` is optional and by default QEMU will search for the 3454 sysfs entry to use. 3455 3456 Some notes about using the host's TPM with the passthrough driver: 3457 3458 The TPM device accessed by the passthrough driver must not be used 3459 by any other application on the host. 3460 3461 Since the host's firmware (BIOS/UEFI) has already initialized the 3462 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3463 the TPM again and may therefore not show a TPM-specific menu that 3464 would otherwise allow the user to configure the TPM, e.g., allow the 3465 user to enable/disable or activate/deactivate the TPM. Further, if 3466 TPM ownership is released from within a VM then the host's TPM will 3467 get disabled and deactivated. To enable and activate the TPM again 3468 afterwards, the host has to be rebooted and the user is required to 3469 enter the firmware's menu to enable and activate the TPM. If the TPM 3470 is left disabled and/or deactivated most TPM commands will fail. 3471 3472 To create a passthrough TPM use the following two options: 3473 3474 :: 3475 3476 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3477 3478 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3479 ``tpmdev=tpm0`` in the device option. 3480 3481``-tpmdev emulator,id=id,chardev=dev`` 3482 (Linux-host only) Enable access to a TPM emulator using Unix domain 3483 socket based chardev backend. 3484 3485 ``chardev`` specifies the unique ID of a character device backend 3486 that provides connection to the software TPM server. 3487 3488 To create a TPM emulator backend device with chardev socket backend: 3489 3490 :: 3491 3492 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3493ERST 3494 3495DEFHEADING() 3496 3497#endif 3498 3499DEFHEADING(Linux/Multiboot boot specific:) 3500SRST 3501When using these options, you can use a given Linux or Multiboot kernel 3502without installing it in the disk image. It can be useful for easier 3503testing of various kernels. 3504 3505 3506ERST 3507 3508DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3509 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3510SRST 3511``-kernel bzImage`` 3512 Use bzImage as kernel image. The kernel can be either a Linux kernel 3513 or in multiboot format. 3514ERST 3515 3516DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3517 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3518SRST 3519``-append cmdline`` 3520 Use cmdline as kernel command line 3521ERST 3522 3523DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3524 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3525SRST 3526``-initrd file`` 3527 Use file as initial ram disk. 3528 3529``-initrd "file1 arg=foo,file2"`` 3530 This syntax is only available with multiboot. 3531 3532 Use file1 and file2 as modules and pass arg=foo as parameter to the 3533 first module. 3534ERST 3535 3536DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3537 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3538SRST 3539``-dtb file`` 3540 Use file as a device tree binary (dtb) image and pass it to the 3541 kernel on boot. 3542ERST 3543 3544DEFHEADING() 3545 3546DEFHEADING(Debug/Expert options:) 3547 3548DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3549 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3550 " Policy for handling deprecated management interfaces\n", 3551 QEMU_ARCH_ALL) 3552SRST 3553``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3554 Set policy for handling deprecated management interfaces (experimental): 3555 3556 ``deprecated-input=accept`` (default) 3557 Accept deprecated commands and arguments 3558 ``deprecated-input=reject`` 3559 Reject deprecated commands and arguments 3560 ``deprecated-input=crash`` 3561 Crash on deprecated commands and arguments 3562 ``deprecated-output=accept`` (default) 3563 Emit deprecated command results and events 3564 ``deprecated-output=hide`` 3565 Suppress deprecated command results and events 3566 3567 Limitation: covers only syntactic aspects of QMP. 3568ERST 3569 3570DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3571 "-fw_cfg [name=]<name>,file=<file>\n" 3572 " add named fw_cfg entry with contents from file\n" 3573 "-fw_cfg [name=]<name>,string=<str>\n" 3574 " add named fw_cfg entry with contents from string\n", 3575 QEMU_ARCH_ALL) 3576SRST 3577``-fw_cfg [name=]name,file=file`` 3578 Add named fw\_cfg entry with contents from file file. 3579 3580``-fw_cfg [name=]name,string=str`` 3581 Add named fw\_cfg entry with contents from string str. 3582 3583 The terminating NUL character of the contents of str will not be 3584 included as part of the fw\_cfg item data. To insert contents with 3585 embedded NUL characters, you have to use the file parameter. 3586 3587 The fw\_cfg entries are passed by QEMU through to the guest. 3588 3589 Example: 3590 3591 :: 3592 3593 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3594 3595 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3596 from ./my\_blob.bin. 3597ERST 3598 3599DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3600 "-serial dev redirect the serial port to char device 'dev'\n", 3601 QEMU_ARCH_ALL) 3602SRST 3603``-serial dev`` 3604 Redirect the virtual serial port to host character device dev. The 3605 default device is ``vc`` in graphical mode and ``stdio`` in non 3606 graphical mode. 3607 3608 This option can be used several times to simulate up to 4 serial 3609 ports. 3610 3611 Use ``-serial none`` to disable all serial ports. 3612 3613 Available character devices are: 3614 3615 ``vc[:WxH]`` 3616 Virtual console. Optionally, a width and height can be given in 3617 pixel with 3618 3619 :: 3620 3621 vc:800x600 3622 3623 It is also possible to specify width or height in characters: 3624 3625 :: 3626 3627 vc:80Cx24C 3628 3629 ``pty`` 3630 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3631 3632 ``none`` 3633 No device is allocated. 3634 3635 ``null`` 3636 void device 3637 3638 ``chardev:id`` 3639 Use a named character device defined with the ``-chardev`` 3640 option. 3641 3642 ``/dev/XXX`` 3643 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3644 port parameters are set according to the emulated ones. 3645 3646 ``/dev/parportN`` 3647 [Linux only, parallel port only] Use host parallel port N. 3648 Currently SPP and EPP parallel port features can be used. 3649 3650 ``file:filename`` 3651 Write output to filename. No character can be read. 3652 3653 ``stdio`` 3654 [Unix only] standard input/output 3655 3656 ``pipe:filename`` 3657 name pipe filename 3658 3659 ``COMn`` 3660 [Windows only] Use host serial port n 3661 3662 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3663 This implements UDP Net Console. When remote\_host or src\_ip 3664 are not specified they default to ``0.0.0.0``. When not using a 3665 specified src\_port a random port is automatically chosen. 3666 3667 If you just want a simple readonly console you can use 3668 ``netcat`` or ``nc``, by starting QEMU with: 3669 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3670 QEMU writes something to that port it will appear in the 3671 netconsole session. 3672 3673 If you plan to send characters back via netconsole or you want 3674 to stop and start QEMU a lot of times, you should have QEMU use 3675 the same source port each time by using something like ``-serial 3676 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3677 version of netcat which can listen to a TCP port and send and 3678 receive characters via udp. If you have a patched version of 3679 netcat which activates telnet remote echo and single char 3680 transfer, then you can use the following options to set up a 3681 netcat redirector to allow telnet on port 5555 to access the 3682 QEMU port. 3683 3684 ``QEMU Options:`` 3685 -serial udp::4555@:4556 3686 3687 ``netcat options:`` 3688 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3689 3690 ``telnet options:`` 3691 localhost 5555 3692 3693 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3694 The TCP Net Console has two modes of operation. It can send the 3695 serial I/O to a location or wait for a connection from a 3696 location. By default the TCP Net Console is sent to host at the 3697 port. If you use the ``server=on`` option QEMU will wait for a client 3698 socket application to connect to the port before continuing, 3699 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3700 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3701 option only applies if ``server=no`` is set, if the connection goes 3702 down it will attempt to reconnect at the given interval. If host 3703 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3704 time is accepted. You can use ``telnet=on`` to connect to the 3705 corresponding character device. 3706 3707 ``Example to send tcp console to 192.168.0.2 port 4444`` 3708 -serial tcp:192.168.0.2:4444 3709 3710 ``Example to listen and wait on port 4444 for connection`` 3711 -serial tcp::4444,server=on 3712 3713 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3714 -serial tcp:192.168.0.100:4444,server=on,wait=off 3715 3716 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3717 The telnet protocol is used instead of raw tcp sockets. The 3718 options work the same as if you had specified ``-serial tcp``. 3719 The difference is that the port acts like a telnet server or 3720 client using telnet option negotiation. This will also allow you 3721 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3722 supports sending the break sequence. Typically in unix telnet 3723 you do it with Control-] and then type "send break" followed by 3724 pressing the enter key. 3725 3726 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3727 The WebSocket protocol is used instead of raw tcp socket. The 3728 port acts as a WebSocket server. Client mode is not supported. 3729 3730 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3731 A unix domain socket is used instead of a tcp socket. The option 3732 works the same as if you had specified ``-serial tcp`` except 3733 the unix domain socket path is used for connections. 3734 3735 ``mon:dev_string`` 3736 This is a special option to allow the monitor to be multiplexed 3737 onto another serial port. The monitor is accessed with key 3738 sequence of Control-a and then pressing c. dev\_string should be 3739 any one of the serial devices specified above. An example to 3740 multiplex the monitor onto a telnet server listening on port 3741 4444 would be: 3742 3743 ``-serial mon:telnet::4444,server=on,wait=off`` 3744 3745 When the monitor is multiplexed to stdio in this way, Ctrl+C 3746 will not terminate QEMU any more but will be passed to the guest 3747 instead. 3748 3749 ``braille`` 3750 Braille device. This will use BrlAPI to display the braille 3751 output on a real or fake device. 3752 3753 ``msmouse`` 3754 Three button serial mouse. Configure the guest to use Microsoft 3755 protocol. 3756ERST 3757 3758DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3759 "-parallel dev redirect the parallel port to char device 'dev'\n", 3760 QEMU_ARCH_ALL) 3761SRST 3762``-parallel dev`` 3763 Redirect the virtual parallel port to host device dev (same devices 3764 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3765 to use hardware devices connected on the corresponding host parallel 3766 port. 3767 3768 This option can be used several times to simulate up to 3 parallel 3769 ports. 3770 3771 Use ``-parallel none`` to disable all parallel ports. 3772ERST 3773 3774DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3775 "-monitor dev redirect the monitor to char device 'dev'\n", 3776 QEMU_ARCH_ALL) 3777SRST 3778``-monitor dev`` 3779 Redirect the monitor to host device dev (same devices as the serial 3780 port). The default device is ``vc`` in graphical mode and ``stdio`` 3781 in non graphical mode. Use ``-monitor none`` to disable the default 3782 monitor. 3783ERST 3784DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3785 "-qmp dev like -monitor but opens in 'control' mode\n", 3786 QEMU_ARCH_ALL) 3787SRST 3788``-qmp dev`` 3789 Like -monitor but opens in 'control' mode. 3790ERST 3791DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3792 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3793 QEMU_ARCH_ALL) 3794SRST 3795``-qmp-pretty dev`` 3796 Like -qmp but uses pretty JSON formatting. 3797ERST 3798 3799DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3800 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3801SRST 3802``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3803 Setup monitor on chardev name. ``mode=control`` configures 3804 a QMP monitor (a JSON RPC-style protocol) and it is not the 3805 same as HMP, the human monitor that has a "(qemu)" prompt. 3806 ``pretty`` is only valid when ``mode=control``, 3807 turning on JSON pretty printing to ease 3808 human reading and debugging. 3809ERST 3810 3811DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3812 "-debugcon dev redirect the debug console to char device 'dev'\n", 3813 QEMU_ARCH_ALL) 3814SRST 3815``-debugcon dev`` 3816 Redirect the debug console to host device dev (same devices as the 3817 serial port). The debug console is an I/O port which is typically 3818 port 0xe9; writing to that I/O port sends output to this device. The 3819 default device is ``vc`` in graphical mode and ``stdio`` in non 3820 graphical mode. 3821ERST 3822 3823DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3824 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3825SRST 3826``-pidfile file`` 3827 Store the QEMU process PID in file. It is useful if you launch QEMU 3828 from a script. 3829ERST 3830 3831DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3832 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3833SRST 3834``-singlestep`` 3835 Run the emulation in single step mode. 3836ERST 3837 3838DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3839 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3840 QEMU_ARCH_ALL) 3841SRST 3842``--preconfig`` 3843 Pause QEMU for interactive configuration before the machine is 3844 created, which allows querying and configuring properties that will 3845 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3846 exit the preconfig state and move to the next state (i.e. run guest 3847 if -S isn't used or pause the second time if -S is used). This 3848 option is experimental. 3849ERST 3850 3851DEF("S", 0, QEMU_OPTION_S, \ 3852 "-S freeze CPU at startup (use 'c' to start execution)\n", 3853 QEMU_ARCH_ALL) 3854SRST 3855``-S`` 3856 Do not start CPU at startup (you must type 'c' in the monitor). 3857ERST 3858 3859DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3860 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3861 " run qemu with overcommit hints\n" 3862 " mem-lock=on|off controls memory lock support (default: off)\n" 3863 " cpu-pm=on|off controls cpu power management (default: off)\n", 3864 QEMU_ARCH_ALL) 3865SRST 3866``-overcommit mem-lock=on|off`` 3867 \ 3868``-overcommit cpu-pm=on|off`` 3869 Run qemu with hints about host resource overcommit. The default is 3870 to assume that host overcommits all resources. 3871 3872 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3873 (disabled by default). This works when host memory is not 3874 overcommitted and reduces the worst-case latency for guest. 3875 3876 Guest ability to manage power state of host cpus (increasing latency 3877 for other processes on the same host cpu, but decreasing latency for 3878 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3879 works best when host CPU is not overcommitted. When used, host 3880 estimates of CPU cycle and power utilization will be incorrect, not 3881 taking into account guest idle time. 3882ERST 3883 3884DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3885 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3886 " the guest without waiting for gdb to connect; use -S too\n" 3887 " if you want it to not start execution.)\n", 3888 QEMU_ARCH_ALL) 3889SRST 3890``-gdb dev`` 3891 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3892 in the System Emulation Users Guide). Note that this option does not pause QEMU 3893 execution -- if you want QEMU to not start the guest until you 3894 connect with gdb and issue a ``continue`` command, you will need to 3895 also pass the ``-S`` option to QEMU. 3896 3897 The most usual configuration is to listen on a local TCP socket:: 3898 3899 -gdb tcp::3117 3900 3901 but you can specify other backends; UDP, pseudo TTY, or even stdio 3902 are all reasonable use cases. For example, a stdio connection 3903 allows you to start QEMU from within gdb and establish the 3904 connection via a pipe: 3905 3906 .. parsed-literal:: 3907 3908 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3909ERST 3910 3911DEF("s", 0, QEMU_OPTION_s, \ 3912 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3913 QEMU_ARCH_ALL) 3914SRST 3915``-s`` 3916 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3917 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3918ERST 3919 3920DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3921 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3922 QEMU_ARCH_ALL) 3923SRST 3924``-d item1[,...]`` 3925 Enable logging of specified items. Use '-d help' for a list of log 3926 items. 3927ERST 3928 3929DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3930 "-D logfile output log to logfile (default stderr)\n", 3931 QEMU_ARCH_ALL) 3932SRST 3933``-D logfile`` 3934 Output log in logfile instead of to stderr 3935ERST 3936 3937DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3938 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3939 QEMU_ARCH_ALL) 3940SRST 3941``-dfilter range1[,...]`` 3942 Filter debug output to that relevant to a range of target addresses. 3943 The filter spec can be either start+size, start-size or start..end 3944 where start end and size are the addresses and sizes required. For 3945 example: 3946 3947 :: 3948 3949 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3950 3951 Will dump output for any code in the 0x1000 sized block starting at 3952 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3953 another 0x1000 sized block starting at 0xffffffc00005f000. 3954ERST 3955 3956DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3957 "-seed number seed the pseudo-random number generator\n", 3958 QEMU_ARCH_ALL) 3959SRST 3960``-seed number`` 3961 Force the guest to use a deterministic pseudo-random number 3962 generator, seeded with number. This does not affect crypto routines 3963 within the host. 3964ERST 3965 3966DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3967 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3968 QEMU_ARCH_ALL) 3969SRST 3970``-L path`` 3971 Set the directory for the BIOS, VGA BIOS and keymaps. 3972 3973 To list all the data directories, use ``-L help``. 3974ERST 3975 3976DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3977 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3978SRST 3979``-bios file`` 3980 Set the filename for the BIOS. 3981ERST 3982 3983DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3984 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3985SRST 3986``-enable-kvm`` 3987 Enable KVM full virtualization support. This option is only 3988 available if KVM support is enabled when compiling. 3989ERST 3990 3991DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3992 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3993DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3994 "-xen-attach attach to existing xen domain\n" 3995 " libxl will use this when starting QEMU\n", 3996 QEMU_ARCH_ALL) 3997DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3998 "-xen-domid-restrict restrict set of available xen operations\n" 3999 " to specified domain id. (Does not affect\n" 4000 " xenpv machine type).\n", 4001 QEMU_ARCH_ALL) 4002SRST 4003``-xen-domid id`` 4004 Specify xen guest domain id (XEN only). 4005 4006``-xen-attach`` 4007 Attach to existing xen domain. libxl will use this when starting 4008 QEMU (XEN only). Restrict set of available xen operations to 4009 specified domain id (XEN only). 4010ERST 4011 4012DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4013 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4014SRST 4015``-no-reboot`` 4016 Exit instead of rebooting. 4017ERST 4018 4019DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4020 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4021SRST 4022``-no-shutdown`` 4023 Don't exit QEMU on guest shutdown, but instead only stop the 4024 emulation. This allows for instance switching to monitor to commit 4025 changes to the disk image. 4026ERST 4027 4028DEF("action", HAS_ARG, QEMU_OPTION_action, 4029 "-action reboot=reset|shutdown\n" 4030 " action when guest reboots [default=reset]\n" 4031 "-action shutdown=poweroff|pause\n" 4032 " action when guest shuts down [default=poweroff]\n" 4033 "-action panic=pause|shutdown|none\n" 4034 " action when guest panics [default=shutdown]\n" 4035 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4036 " action when watchdog fires [default=reset]\n", 4037 QEMU_ARCH_ALL) 4038SRST 4039``-action event=action`` 4040 The action parameter serves to modify QEMU's default behavior when 4041 certain guest events occur. It provides a generic method for specifying the 4042 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4043 parameters. 4044 4045 Examples: 4046 4047 ``-action panic=none`` 4048 ``-action reboot=shutdown,shutdown=pause`` 4049 ``-watchdog i6300esb -action watchdog=pause`` 4050 4051ERST 4052 4053DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4054 "-loadvm [tag|id]\n" \ 4055 " start right away with a saved state (loadvm in monitor)\n", 4056 QEMU_ARCH_ALL) 4057SRST 4058``-loadvm file`` 4059 Start right away with a saved state (``loadvm`` in monitor) 4060ERST 4061 4062#ifndef _WIN32 4063DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4064 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4065#endif 4066SRST 4067``-daemonize`` 4068 Daemonize the QEMU process after initialization. QEMU will not 4069 detach from standard IO until it is ready to receive connections on 4070 any of its devices. This option is a useful way for external 4071 programs to launch QEMU without having to cope with initialization 4072 race conditions. 4073ERST 4074 4075DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4076 "-option-rom rom load a file, rom, into the option ROM space\n", 4077 QEMU_ARCH_ALL) 4078SRST 4079``-option-rom file`` 4080 Load the contents of file as an option ROM. This option is useful to 4081 load things like EtherBoot. 4082ERST 4083 4084DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4085 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4086 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4087 QEMU_ARCH_ALL) 4088 4089SRST 4090``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4091 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4092 the current UTC or local time, respectively. ``localtime`` is 4093 required for correct date in MS-DOS or Windows. To start at a 4094 specific point in time, provide datetime in the format 4095 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4096 4097 By default the RTC is driven by the host system time. This allows 4098 using of the RTC as accurate reference clock inside the guest, 4099 specifically if the host time is smoothly following an accurate 4100 external reference clock, e.g. via NTP. If you want to isolate the 4101 guest time from the host, you can set ``clock`` to ``rt`` instead, 4102 which provides a host monotonic clock if host support it. To even 4103 prevent the RTC from progressing during suspension, you can set 4104 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4105 recommended especially in icount mode in order to preserve 4106 determinism; however, note that in icount mode the speed of the 4107 virtual clock is variable and can in general differ from the host 4108 clock. 4109 4110 Enable ``driftfix`` (i386 targets only) if you experience time drift 4111 problems, specifically with Windows' ACPI HAL. This option will try 4112 to figure out how many timer interrupts were not processed by the 4113 Windows guest and will re-inject them. 4114ERST 4115 4116DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4117 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4118 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4119 " instruction, enable aligning the host and virtual clocks\n" \ 4120 " or disable real time cpu sleeping, and optionally enable\n" \ 4121 " record-and-replay mode\n", QEMU_ARCH_ALL) 4122SRST 4123``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4124 Enable virtual instruction counter. The virtual cpu will execute one 4125 instruction every 2^N ns of virtual time. If ``auto`` is specified 4126 then the virtual cpu speed will be automatically adjusted to keep 4127 virtual time within a few seconds of real time. 4128 4129 Note that while this option can give deterministic behavior, it does 4130 not provide cycle accurate emulation. Modern CPUs contain 4131 superscalar out of order cores with complex cache hierarchies. The 4132 number of instructions executed often has little or no correlation 4133 with actual performance. 4134 4135 When the virtual cpu is sleeping, the virtual time will advance at 4136 default speed unless ``sleep=on`` is specified. With 4137 ``sleep=on``, the virtual time will jump to the next timer 4138 deadline instantly whenever the virtual cpu goes to sleep mode and 4139 will not advance if no timer is enabled. This behavior gives 4140 deterministic execution times from the guest point of view. 4141 The default if icount is enabled is ``sleep=off``. 4142 ``sleep=on`` cannot be used together with either ``shift=auto`` 4143 or ``align=on``. 4144 4145 ``align=on`` will activate the delay algorithm which will try to 4146 synchronise the host clock and the virtual clock. The goal is to 4147 have a guest running at the real frequency imposed by the shift 4148 option. Whenever the guest clock is behind the host clock and if 4149 ``align=on`` is specified then we print a message to the user to 4150 inform about the delay. Currently this option does not work when 4151 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4152 shift values for which the guest clock runs ahead of the host clock. 4153 Typically this happens when the shift value is high (how high 4154 depends on the host machine). The default if icount is enabled 4155 is ``align=off``. 4156 4157 When the ``rr`` option is specified deterministic record/replay is 4158 enabled. The ``rrfile=`` option must also be provided to 4159 specify the path to the replay log. In record mode data is written 4160 to this file, and in replay mode it is read back. 4161 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4162 name. In record mode, a new VM snapshot with the given name is created 4163 at the start of execution recording. In replay mode this option 4164 specifies the snapshot name used to load the initial VM state. 4165ERST 4166 4167DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4168 "-watchdog model\n" \ 4169 " enable virtual hardware watchdog [default=none]\n", 4170 QEMU_ARCH_ALL) 4171SRST 4172``-watchdog model`` 4173 Create a virtual hardware watchdog device. Once enabled (by a guest 4174 action), the watchdog must be periodically polled by an agent inside 4175 the guest or else the guest will be restarted. Choose a model for 4176 which your guest has drivers. 4177 4178 The model is the model of hardware watchdog to emulate. Use 4179 ``-watchdog help`` to list available hardware models. Only one 4180 watchdog can be enabled for a guest. 4181 4182 The following models may be available: 4183 4184 ``ib700`` 4185 iBASE 700 is a very simple ISA watchdog with a single timer. 4186 4187 ``i6300esb`` 4188 Intel 6300ESB I/O controller hub is a much more featureful 4189 PCI-based dual-timer watchdog. 4190 4191 ``diag288`` 4192 A virtual watchdog for s390x backed by the diagnose 288 4193 hypercall (currently KVM only). 4194ERST 4195 4196DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4197 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4198 " action when watchdog fires [default=reset]\n", 4199 QEMU_ARCH_ALL) 4200SRST 4201``-watchdog-action action`` 4202 The action controls what QEMU will do when the watchdog timer 4203 expires. The default is ``reset`` (forcefully reset the guest). 4204 Other possible actions are: ``shutdown`` (attempt to gracefully 4205 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4206 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4207 guest), ``debug`` (print a debug message and continue), or ``none`` 4208 (do nothing). 4209 4210 Note that the ``shutdown`` action requires that the guest responds 4211 to ACPI signals, which it may not be able to do in the sort of 4212 situations where the watchdog would have expired, and thus 4213 ``-watchdog-action shutdown`` is not recommended for production use. 4214 4215 Examples: 4216 4217 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4218 4219ERST 4220 4221DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4222 "-echr chr set terminal escape character instead of ctrl-a\n", 4223 QEMU_ARCH_ALL) 4224SRST 4225``-echr numeric_ascii_value`` 4226 Change the escape character used for switching to the monitor when 4227 using monitor and serial sharing. The default is ``0x01`` when using 4228 the ``-nographic`` option. ``0x01`` is equal to pressing 4229 ``Control-a``. You can select a different character from the ascii 4230 control keys where 1 through 26 map to Control-a through Control-z. 4231 For instance you could use the either of the following to change the 4232 escape character to Control-t. 4233 4234 ``-echr 0x14``; \ ``-echr 20`` 4235 4236ERST 4237 4238DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4239 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4240 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4241 "-incoming unix:socketpath\n" \ 4242 " prepare for incoming migration, listen on\n" \ 4243 " specified protocol and socket address\n" \ 4244 "-incoming fd:fd\n" \ 4245 "-incoming exec:cmdline\n" \ 4246 " accept incoming migration on given file descriptor\n" \ 4247 " or from given external command\n" \ 4248 "-incoming defer\n" \ 4249 " wait for the URI to be specified via migrate_incoming\n", 4250 QEMU_ARCH_ALL) 4251SRST 4252``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4253 \ 4254``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4255 Prepare for incoming migration, listen on a given tcp port. 4256 4257``-incoming unix:socketpath`` 4258 Prepare for incoming migration, listen on a given unix socket. 4259 4260``-incoming fd:fd`` 4261 Accept incoming migration from a given filedescriptor. 4262 4263``-incoming exec:cmdline`` 4264 Accept incoming migration as an output from specified external 4265 command. 4266 4267``-incoming defer`` 4268 Wait for the URI to be specified via migrate\_incoming. The monitor 4269 can be used to change settings (such as migration parameters) prior 4270 to issuing the migrate\_incoming to allow the migration to begin. 4271ERST 4272 4273DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4274 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4275SRST 4276``-only-migratable`` 4277 Only allow migratable devices. Devices will not be allowed to enter 4278 an unmigratable state. 4279ERST 4280 4281DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4282 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4283SRST 4284``-nodefaults`` 4285 Don't create default devices. Normally, QEMU sets the default 4286 devices like serial port, parallel port, virtual console, monitor 4287 device, VGA adapter, floppy and CD-ROM drive and others. The 4288 ``-nodefaults`` option will disable all those default devices. 4289ERST 4290 4291#ifndef _WIN32 4292DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4293 "-chroot dir chroot to dir just before starting the VM\n", 4294 QEMU_ARCH_ALL) 4295#endif 4296SRST 4297``-chroot dir`` 4298 Immediately before starting guest execution, chroot to the specified 4299 directory. Especially useful in combination with -runas. 4300ERST 4301 4302#ifndef _WIN32 4303DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4304 "-runas user change to user id user just before starting the VM\n" \ 4305 " user can be numeric uid:gid instead\n", 4306 QEMU_ARCH_ALL) 4307#endif 4308SRST 4309``-runas user`` 4310 Immediately before starting guest execution, drop root privileges, 4311 switching to the specified user. 4312ERST 4313 4314DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4315 "-prom-env variable=value\n" 4316 " set OpenBIOS nvram variables\n", 4317 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4318SRST 4319``-prom-env variable=value`` 4320 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4321 4322 :: 4323 4324 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4325 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4326 4327 :: 4328 4329 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4330 -prom-env 'boot-device=hd:2,\yaboot' \ 4331 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4332ERST 4333DEF("semihosting", 0, QEMU_OPTION_semihosting, 4334 "-semihosting semihosting mode\n", 4335 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4336 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4337SRST 4338``-semihosting`` 4339 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4340 4341 Note that this allows guest direct access to the host filesystem, so 4342 should only be used with a trusted guest OS. 4343 4344 See the -semihosting-config option documentation for further 4345 information about the facilities this enables. 4346ERST 4347DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4348 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4349 " semihosting configuration\n", 4350QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4351QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4352SRST 4353``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4354 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4355 only). 4356 4357 Note that this allows guest direct access to the host filesystem, so 4358 should only be used with a trusted guest OS. 4359 4360 On Arm this implements the standard semihosting API, version 2.0. 4361 4362 On M68K this implements the "ColdFire GDB" interface used by 4363 libgloss. 4364 4365 Xtensa semihosting provides basic file IO calls, such as 4366 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4367 linux platform "sim" use this interface. 4368 4369 On RISC-V this implements the standard semihosting API, version 0.2. 4370 4371 ``target=native|gdb|auto`` 4372 Defines where the semihosting calls will be addressed, to QEMU 4373 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4374 means ``gdb`` during debug sessions and ``native`` otherwise. 4375 4376 ``chardev=str1`` 4377 Send the output to a chardev backend output for native or auto 4378 output when not in gdb 4379 4380 ``arg=str1,arg=str2,...`` 4381 Allows the user to pass input arguments, and can be used 4382 multiple times to build up a list. The old-style 4383 ``-kernel``/``-append`` method of passing a command line is 4384 still supported for backward compatibility. If both the 4385 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4386 specified, the former is passed to semihosting as it always 4387 takes precedence. 4388ERST 4389DEF("old-param", 0, QEMU_OPTION_old_param, 4390 "-old-param old param mode\n", QEMU_ARCH_ARM) 4391SRST 4392``-old-param`` 4393 Old param mode (ARM only). 4394ERST 4395 4396DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4397 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4398 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4399 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4400 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4401 " by the kernel, but typically no longer used by modern\n" \ 4402 " C library implementations.\n" \ 4403 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4404 " to elevate privileges using set*uid|gid system calls.\n" \ 4405 " The value 'children' will deny set*uid|gid system calls for\n" \ 4406 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4407 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4408 " blocking *fork and execve\n" \ 4409 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4410 QEMU_ARCH_ALL) 4411SRST 4412``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4413 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4414 filtering and 'off' will disable it. The default is 'off'. 4415 4416 ``obsolete=string`` 4417 Enable Obsolete system calls 4418 4419 ``elevateprivileges=string`` 4420 Disable set\*uid\|gid system calls 4421 4422 ``spawn=string`` 4423 Disable \*fork and execve 4424 4425 ``resourcecontrol=string`` 4426 Disable process affinity and schedular priority 4427ERST 4428 4429DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4430 "-readconfig <file>\n", QEMU_ARCH_ALL) 4431SRST 4432``-readconfig file`` 4433 Read device configuration from file. This approach is useful when 4434 you want to spawn QEMU process with many command line options but 4435 you don't want to exceed the command line character limit. 4436ERST 4437DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4438 "-writeconfig <file>\n" 4439 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4440SRST 4441ERST 4442 4443DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4444 "-no-user-config\n" 4445 " do not load default user-provided config files at startup\n", 4446 QEMU_ARCH_ALL) 4447SRST 4448``-no-user-config`` 4449 The ``-no-user-config`` option makes QEMU not load any of the 4450 user-provided config files on sysconfdir. 4451ERST 4452 4453DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4454 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4455 " specify tracing options\n", 4456 QEMU_ARCH_ALL) 4457SRST 4458``-trace [[enable=]pattern][,events=file][,file=file]`` 4459 .. include:: ../qemu-option-trace.rst.inc 4460 4461ERST 4462DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4463 "-plugin [file=]<file>[,arg=<string>]\n" 4464 " load a plugin\n", 4465 QEMU_ARCH_ALL) 4466SRST 4467``-plugin file=file[,arg=string]`` 4468 Load a plugin. 4469 4470 ``file=file`` 4471 Load the given plugin from a shared library file. 4472 4473 ``arg=string`` 4474 Argument string passed to the plugin. (Can be given multiple 4475 times.) 4476ERST 4477 4478HXCOMM Internal use 4479DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4480DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4481 4482#ifdef __linux__ 4483DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4484 "-enable-fips enable FIPS 140-2 compliance\n", 4485 QEMU_ARCH_ALL) 4486#endif 4487SRST 4488``-enable-fips`` 4489 Enable FIPS 140-2 compliance mode. 4490ERST 4491 4492DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4493 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4494 " control error message format\n" 4495 " timestamp=on enables timestamps (default: off)\n" 4496 " guest-name=on enables guest name prefix but only if\n" 4497 " -name guest option is set (default: off)\n", 4498 QEMU_ARCH_ALL) 4499SRST 4500``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4501 Control error message format. 4502 4503 ``timestamp=on|off`` 4504 Prefix messages with a timestamp. Default is off. 4505 4506 ``guest-name=on|off`` 4507 Prefix messages with guest name but only if -name guest option is set 4508 otherwise the option is ignored. Default is off. 4509ERST 4510 4511DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4512 "-dump-vmstate <file>\n" 4513 " Output vmstate information in JSON format to file.\n" 4514 " Use the scripts/vmstate-static-checker.py file to\n" 4515 " check for possible regressions in migration code\n" 4516 " by comparing two such vmstate dumps.\n", 4517 QEMU_ARCH_ALL) 4518SRST 4519``-dump-vmstate file`` 4520 Dump json-encoded vmstate information for current machine type to 4521 file in file 4522ERST 4523 4524DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4525 "-enable-sync-profile\n" 4526 " enable synchronization profiling\n", 4527 QEMU_ARCH_ALL) 4528SRST 4529``-enable-sync-profile`` 4530 Enable synchronization profiling. 4531ERST 4532 4533DEFHEADING() 4534 4535DEFHEADING(Generic object creation:) 4536 4537DEF("object", HAS_ARG, QEMU_OPTION_object, 4538 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4539 " create a new object of type TYPENAME setting properties\n" 4540 " in the order they are specified. Note that the 'id'\n" 4541 " property must be set. These objects are placed in the\n" 4542 " '/objects' path.\n", 4543 QEMU_ARCH_ALL) 4544SRST 4545``-object typename[,prop1=value1,...]`` 4546 Create a new object of type typename setting properties in the order 4547 they are specified. Note that the 'id' property must be set. These 4548 objects are placed in the '/objects' path. 4549 4550 ``-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`` 4551 Creates a memory file backend object, which can be used to back 4552 the guest RAM with huge pages. 4553 4554 The ``id`` parameter is a unique ID that will be used to 4555 reference this memory region in other parameters, e.g. ``-numa``, 4556 ``-device nvdimm``, etc. 4557 4558 The ``size`` option provides the size of the memory region, and 4559 accepts common suffixes, e.g. ``500M``. 4560 4561 The ``mem-path`` provides the path to either a shared memory or 4562 huge page filesystem mount. 4563 4564 The ``share`` boolean option determines whether the memory 4565 region is marked as private to QEMU, or shared. The latter 4566 allows a co-operating external process to access the QEMU memory 4567 region. 4568 4569 The ``share`` is also required for pvrdma devices due to 4570 limitations in the RDMA API provided by Linux. 4571 4572 Setting share=on might affect the ability to configure NUMA 4573 bindings for the memory backend under some circumstances, see 4574 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4575 source tree for additional details. 4576 4577 Setting the ``discard-data`` boolean option to on indicates that 4578 file contents can be destroyed when QEMU exits, to avoid 4579 unnecessarily flushing data to the backing file. Note that 4580 ``discard-data`` is only an optimization, and QEMU might not 4581 discard file contents if it aborts unexpectedly or is terminated 4582 using SIGKILL. 4583 4584 The ``merge`` boolean option enables memory merge, also known as 4585 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4586 the pages for memory deduplication. 4587 4588 Setting the ``dump`` boolean option to off excludes the memory 4589 from core dumps. This feature is also known as MADV\_DONTDUMP. 4590 4591 The ``prealloc`` boolean option enables memory preallocation. 4592 4593 The ``host-nodes`` option binds the memory range to a list of 4594 NUMA host nodes. 4595 4596 The ``policy`` option sets the NUMA policy to one of the 4597 following values: 4598 4599 ``default`` 4600 default host policy 4601 4602 ``preferred`` 4603 prefer the given host node list for allocation 4604 4605 ``bind`` 4606 restrict memory allocation to the given host node list 4607 4608 ``interleave`` 4609 interleave memory allocations across the given host node 4610 list 4611 4612 The ``align`` option specifies the base address alignment when 4613 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4614 ``2M``. Some backend store specified by ``mem-path`` requires an 4615 alignment different than the default one used by QEMU, eg the 4616 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4617 such cases, users can specify the required alignment via this 4618 option. 4619 4620 The ``pmem`` option specifies whether the backing file specified 4621 by ``mem-path`` is in host persistent memory that can be 4622 accessed using the SNIA NVM programming model (e.g. Intel 4623 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4624 operations to guarantee the persistence of its own writes to 4625 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4626 migration). Also, we will map the backend-file with MAP\_SYNC 4627 flag, which ensures the file metadata is in sync for 4628 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4629 requires support from both the host kernel (since Linux kernel 4630 4.15) and the filesystem of ``mem-path`` mounted with DAX 4631 option. 4632 4633 The ``readonly`` option specifies whether the backing file is opened 4634 read-only or read-write (default). 4635 4636 ``-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`` 4637 Creates a memory backend object, which can be used to back the 4638 guest RAM. Memory backend objects offer more control than the 4639 ``-m`` option that is traditionally used to define guest RAM. 4640 Please refer to ``memory-backend-file`` for a description of the 4641 options. 4642 4643 ``-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`` 4644 Creates an anonymous memory file backend object, which allows 4645 QEMU to share the memory with an external process (e.g. when 4646 using vhost-user). The memory is allocated with memfd and 4647 optional sealing. (Linux only) 4648 4649 The ``seal`` option creates a sealed-file, that will block 4650 further resizing the memory ('on' by default). 4651 4652 The ``hugetlb`` option specify the file to be created resides in 4653 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4654 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4655 the hugetlb page size on systems that support multiple hugetlb 4656 page sizes (it must be a power of 2 value supported by the 4657 system). 4658 4659 In some versions of Linux, the ``hugetlb`` option is 4660 incompatible with the ``seal`` option (requires at least Linux 4661 4.16). 4662 4663 Please refer to ``memory-backend-file`` for a description of the 4664 other options. 4665 4666 The ``share`` boolean option is on by default with memfd. 4667 4668 ``-object rng-builtin,id=id`` 4669 Creates a random number generator backend which obtains entropy 4670 from QEMU builtin functions. The ``id`` parameter is a unique ID 4671 that will be used to reference this entropy backend from the 4672 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4673 uses this RNG backend. 4674 4675 ``-object rng-random,id=id,filename=/dev/random`` 4676 Creates a random number generator backend which obtains entropy 4677 from a device on the host. The ``id`` parameter is a unique ID 4678 that will be used to reference this entropy backend from the 4679 ``virtio-rng`` device. The ``filename`` parameter specifies 4680 which file to obtain entropy from and if omitted defaults to 4681 ``/dev/urandom``. 4682 4683 ``-object rng-egd,id=id,chardev=chardevid`` 4684 Creates a random number generator backend which obtains entropy 4685 from an external daemon running on the host. The ``id`` 4686 parameter is a unique ID that will be used to reference this 4687 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4688 parameter is the unique ID of a character device backend that 4689 provides the connection to the RNG daemon. 4690 4691 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4692 Creates a TLS anonymous credentials object, which can be used to 4693 provide TLS support on network backends. The ``id`` parameter is 4694 a unique ID which network backends will use to access the 4695 credentials. The ``endpoint`` is either ``server`` or ``client`` 4696 depending on whether the QEMU network backend that uses the 4697 credentials will be acting as a client or as a server. If 4698 ``verify-peer`` is enabled (the default) then once the handshake 4699 is completed, the peer credentials will be verified, though this 4700 is a no-op for anonymous credentials. 4701 4702 The dir parameter tells QEMU where to find the credential files. 4703 For server endpoints, this directory may contain a file 4704 dh-params.pem providing diffie-hellman parameters to use for the 4705 TLS server. If the file is missing, QEMU will generate a set of 4706 DH parameters at startup. This is a computationally expensive 4707 operation that consumes random pool entropy, so it is 4708 recommended that a persistent set of parameters be generated 4709 upfront and saved. 4710 4711 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4712 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4713 can be used to provide TLS support on network backends. The 4714 ``id`` parameter is a unique ID which network backends will use 4715 to access the credentials. The ``endpoint`` is either ``server`` 4716 or ``client`` depending on whether the QEMU network backend that 4717 uses the credentials will be acting as a client or as a server. 4718 For clients only, ``username`` is the username which will be 4719 sent to the server. If omitted it defaults to "qemu". 4720 4721 The dir parameter tells QEMU where to find the keys file. It is 4722 called "dir/keys.psk" and contains "username:key" pairs. This 4723 file can most easily be created using the GnuTLS ``psktool`` 4724 program. 4725 4726 For server endpoints, dir may also contain a file dh-params.pem 4727 providing diffie-hellman parameters to use for the TLS server. 4728 If the file is missing, QEMU will generate a set of DH 4729 parameters at startup. This is a computationally expensive 4730 operation that consumes random pool entropy, so it is 4731 recommended that a persistent set of parameters be generated up 4732 front and saved. 4733 4734 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4735 Creates a TLS anonymous credentials object, which can be used to 4736 provide TLS support on network backends. The ``id`` parameter is 4737 a unique ID which network backends will use to access the 4738 credentials. The ``endpoint`` is either ``server`` or ``client`` 4739 depending on whether the QEMU network backend that uses the 4740 credentials will be acting as a client or as a server. If 4741 ``verify-peer`` is enabled (the default) then once the handshake 4742 is completed, the peer credentials will be verified. With x509 4743 certificates, this implies that the clients must be provided 4744 with valid client certificates too. 4745 4746 The dir parameter tells QEMU where to find the credential files. 4747 For server endpoints, this directory may contain a file 4748 dh-params.pem providing diffie-hellman parameters to use for the 4749 TLS server. If the file is missing, QEMU will generate a set of 4750 DH parameters at startup. This is a computationally expensive 4751 operation that consumes random pool entropy, so it is 4752 recommended that a persistent set of parameters be generated 4753 upfront and saved. 4754 4755 For x509 certificate credentials the directory will contain 4756 further files providing the x509 certificates. The certificates 4757 must be stored in PEM format, in filenames ca-cert.pem, 4758 ca-crl.pem (optional), server-cert.pem (only servers), 4759 server-key.pem (only servers), client-cert.pem (only clients), 4760 and client-key.pem (only clients). 4761 4762 For the server-key.pem and client-key.pem files which contain 4763 sensitive private keys, it is possible to use an encrypted 4764 version by providing the passwordid parameter. This provides the 4765 ID of a previously created ``secret`` object containing the 4766 password for decryption. 4767 4768 The priority parameter allows to override the global default 4769 priority used by gnutls. This can be useful if the system 4770 administrator needs to use a weaker set of crypto priorities for 4771 QEMU without potentially forcing the weakness onto all 4772 applications. Or conversely if one wants wants a stronger 4773 default for QEMU than for all other applications, they can do 4774 this through this parameter. Its format is a gnutls priority 4775 string as described at 4776 https://gnutls.org/manual/html_node/Priority-Strings.html. 4777 4778 ``-object tls-cipher-suites,id=id,priority=priority`` 4779 Creates a TLS cipher suites object, which can be used to control 4780 the TLS cipher/protocol algorithms that applications are permitted 4781 to use. 4782 4783 The ``id`` parameter is a unique ID which frontends will use to 4784 access the ordered list of permitted TLS cipher suites from the 4785 host. 4786 4787 The ``priority`` parameter allows to override the global default 4788 priority used by gnutls. This can be useful if the system 4789 administrator needs to use a weaker set of crypto priorities for 4790 QEMU without potentially forcing the weakness onto all 4791 applications. Or conversely if one wants wants a stronger 4792 default for QEMU than for all other applications, they can do 4793 this through this parameter. Its format is a gnutls priority 4794 string as described at 4795 https://gnutls.org/manual/html_node/Priority-Strings.html. 4796 4797 An example of use of this object is to control UEFI HTTPS Boot. 4798 The tls-cipher-suites object exposes the ordered list of permitted 4799 TLS cipher suites from the host side to the guest firmware, via 4800 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4801 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4802 guest-side TLS. 4803 4804 In the following example, the priority at which the host-side policy 4805 is retrieved is given by the ``priority`` property. 4806 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4807 refer to /etc/crypto-policies/back-ends/gnutls.config. 4808 4809 .. parsed-literal:: 4810 4811 # |qemu_system| \\ 4812 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4813 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4814 4815 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4816 Interval t can't be 0, this filter batches the packet delivery: 4817 all packets arriving in a given interval on netdev netdevid are 4818 delayed until the end of the interval. Interval is in 4819 microseconds. ``status`` is optional that indicate whether the 4820 netfilter is on (enabled) or off (disabled), the default status 4821 for netfilter will be 'on'. 4822 4823 queue all\|rx\|tx is an option that can be applied to any 4824 netfilter. 4825 4826 ``all``: the filter is attached both to the receive and the 4827 transmit queue of the netdev (default). 4828 4829 ``rx``: the filter is attached to the receive queue of the 4830 netdev, where it will receive packets sent to the netdev. 4831 4832 ``tx``: the filter is attached to the transmit queue of the 4833 netdev, where it will receive packets sent by the netdev. 4834 4835 position head\|tail\|id=<id> is an option to specify where the 4836 filter should be inserted in the filter list. It can be applied 4837 to any netfilter. 4838 4839 ``head``: the filter is inserted at the head of the filter list, 4840 before any existing filters. 4841 4842 ``tail``: the filter is inserted at the tail of the filter list, 4843 behind any existing filters (default). 4844 4845 ``id=<id>``: the filter is inserted before or behind the filter 4846 specified by <id>, see the insert option below. 4847 4848 insert behind\|before is an option to specify where to insert 4849 the new filter relative to the one specified with 4850 position=id=<id>. It can be applied to any netfilter. 4851 4852 ``before``: insert before the specified filter. 4853 4854 ``behind``: insert behind the specified filter (default). 4855 4856 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4857 filter-mirror on netdev netdevid,mirror net packet to 4858 chardevchardevid, if it has the vnet\_hdr\_support flag, 4859 filter-mirror will mirror packet with vnet\_hdr\_len. 4860 4861 ``-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]`` 4862 filter-redirector on netdev netdevid,redirect filter's net 4863 packet to chardev chardevid,and redirect indev's packet to 4864 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4865 will redirect packet with vnet\_hdr\_len. Create a 4866 filter-redirector we need to differ outdev id from indev id, id 4867 can not be the same. we can just use indev or outdev, but at 4868 least one of indev or outdev need to be specified. 4869 4870 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4871 Filter-rewriter is a part of COLO project.It will rewrite tcp 4872 packet to secondary from primary to keep secondary tcp 4873 connection,and rewrite tcp packet to primary from secondary make 4874 tcp packet can be handled by client.if it has the 4875 vnet\_hdr\_support flag, we can parse packet with vnet header. 4876 4877 usage: colo secondary: -object 4878 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4879 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4880 filter-rewriter,id=rew0,netdev=hn0,queue=all 4881 4882 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4883 Dump the network traffic on netdev dev to the file specified by 4884 filename. At most len bytes (64k by default) per packet are 4885 stored. The file format is libpcap, so it can be analyzed with 4886 tools such as tcpdump or Wireshark. 4887 4888 ``-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}]`` 4889 Colo-compare gets packet from primary\_in chardevid and 4890 secondary\_in, then compare whether the payload of primary packet 4891 and secondary packet are the same. If same, it will output 4892 primary packet to out\_dev, else it will notify COLO-framework to do 4893 checkpoint and send primary packet to out\_dev. In order to 4894 improve efficiency, we need to put the task of comparison in 4895 another iothread. If it has the vnet\_hdr\_support flag, 4896 colo compare will send/recv packet with vnet\_hdr\_len. 4897 The compare\_timeout=@var{ms} determines the maximum time of the 4898 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4899 is to set the period of scanning expired primary node network packets. 4900 The max\_queue\_size=@var{size} is to set the max compare queue 4901 size depend on user environment. 4902 If user want to use Xen COLO, need to add the notify\_dev to 4903 notify Xen colo-frame to do checkpoint. 4904 4905 COLO-compare must be used with the help of filter-mirror, 4906 filter-redirector and filter-rewriter. 4907 4908 :: 4909 4910 KVM COLO 4911 4912 primary: 4913 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4914 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4915 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4916 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4917 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4918 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4919 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4920 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4921 -object iothread,id=iothread1 4922 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4923 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4924 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4925 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4926 4927 secondary: 4928 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4929 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4930 -chardev socket,id=red0,host=3.3.3.3,port=9003 4931 -chardev socket,id=red1,host=3.3.3.3,port=9004 4932 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4933 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4934 4935 4936 Xen COLO 4937 4938 primary: 4939 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4940 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4941 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4942 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4943 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4944 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4945 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4946 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4947 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 4948 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4949 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4950 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4951 -object iothread,id=iothread1 4952 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4953 4954 secondary: 4955 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4956 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4957 -chardev socket,id=red0,host=3.3.3.3,port=9003 4958 -chardev socket,id=red1,host=3.3.3.3,port=9004 4959 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4960 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4961 4962 If you want to know the detail of above command line, you can 4963 read the colo-compare git log. 4964 4965 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4966 Creates a cryptodev backend which executes crypto opreation from 4967 the QEMU cipher APIS. The id parameter is a unique ID that will 4968 be used to reference this cryptodev backend from the 4969 ``virtio-crypto`` device. The queues parameter is optional, 4970 which specify the queue number of cryptodev backend, the default 4971 of queues is 1. 4972 4973 .. parsed-literal:: 4974 4975 # |qemu_system| \\ 4976 [...] \\ 4977 -object cryptodev-backend-builtin,id=cryptodev0 \\ 4978 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4979 [...] 4980 4981 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4982 Creates a vhost-user cryptodev backend, backed by a chardev 4983 chardevid. The id parameter is a unique ID that will be used to 4984 reference this cryptodev backend from the ``virtio-crypto`` 4985 device. The chardev should be a unix domain socket backed one. 4986 The vhost-user uses a specifically defined protocol to pass 4987 vhost ioctl replacement messages to an application on the other 4988 end of the socket. The queues parameter is optional, which 4989 specify the queue number of cryptodev backend for multiqueue 4990 vhost-user, the default of queues is 1. 4991 4992 .. parsed-literal:: 4993 4994 # |qemu_system| \\ 4995 [...] \\ 4996 -chardev socket,id=chardev0,path=/path/to/socket \\ 4997 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 4998 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4999 [...] 5000 5001 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5002 \ 5003 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5004 Defines a secret to store a password, encryption key, or some 5005 other sensitive data. The sensitive data can either be passed 5006 directly via the data parameter, or indirectly via the file 5007 parameter. Using the data parameter is insecure unless the 5008 sensitive data is encrypted. 5009 5010 The sensitive data can be provided in raw format (the default), 5011 or base64. When encoded as JSON, the raw format only supports 5012 valid UTF-8 characters, so base64 is recommended for sending 5013 binary data. QEMU will convert from which ever format is 5014 provided to the format it needs internally. eg, an RBD password 5015 can be provided in raw format, even though it will be base64 5016 encoded when passed onto the RBD sever. 5017 5018 For added protection, it is possible to encrypt the data 5019 associated with a secret using the AES-256-CBC cipher. Use of 5020 encryption is indicated by providing the keyid and iv 5021 parameters. The keyid parameter provides the ID of a previously 5022 defined secret that contains the AES-256 decryption key. This 5023 key should be 32-bytes long and be base64 encoded. The iv 5024 parameter provides the random initialization vector used for 5025 encryption of this particular secret and should be a base64 5026 encrypted string of the 16-byte IV. 5027 5028 The simplest (insecure) usage is to provide the secret inline 5029 5030 .. parsed-literal:: 5031 5032 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5033 5034 The simplest secure usage is to provide the secret via a file 5035 5036 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5037 secret,id=sec0,file=mypasswd.txt,format=raw 5038 5039 For greater security, AES-256-CBC should be used. To illustrate 5040 usage, consider the openssl command line tool which can encrypt 5041 the data. Note that when encrypting, the plaintext must be 5042 padded to the cipher block size (32 bytes) using the standard 5043 PKCS#5/6 compatible padding algorithm. 5044 5045 First a master key needs to be created in base64 encoding: 5046 5047 :: 5048 5049 # openssl rand -base64 32 > key.b64 5050 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5051 5052 Each secret to be encrypted needs to have a random 5053 initialization vector generated. These do not need to be kept 5054 secret 5055 5056 :: 5057 5058 # openssl rand -base64 16 > iv.b64 5059 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5060 5061 The secret to be defined can now be encrypted, in this case 5062 we're telling openssl to base64 encode the result, but it could 5063 be left as raw bytes if desired. 5064 5065 :: 5066 5067 # SECRET=$(printf "letmein" | 5068 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5069 5070 When launching QEMU, create a master secret pointing to 5071 ``key.b64`` and specify that to be used to decrypt the user 5072 password. Pass the contents of ``iv.b64`` to the second secret 5073 5074 .. parsed-literal:: 5075 5076 # |qemu_system| \\ 5077 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5078 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5079 data=$SECRET,iv=$(<iv.b64) 5080 5081 ``-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]`` 5082 Create a Secure Encrypted Virtualization (SEV) guest object, 5083 which can be used to provide the guest memory encryption support 5084 on AMD processors. 5085 5086 When memory encryption is enabled, one of the physical address 5087 bit (aka the C-bit) is utilized to mark if a memory page is 5088 protected. The ``cbitpos`` is used to provide the C-bit 5089 position. The C-bit position is Host family dependent hence user 5090 must provide this value. On EPYC, the value should be 47. 5091 5092 When memory encryption is enabled, we loose certain bits in 5093 physical address space. The ``reduced-phys-bits`` is used to 5094 provide the number of bits we loose in physical address space. 5095 Similar to C-bit, the value is Host family dependent. On EPYC, 5096 the value should be 5. 5097 5098 The ``sev-device`` provides the device file to use for 5099 communicating with the SEV firmware running inside AMD Secure 5100 Processor. The default device is '/dev/sev'. If hardware 5101 supports memory encryption then /dev/sev devices are created by 5102 CCP driver. 5103 5104 The ``policy`` provides the guest policy to be enforced by the 5105 SEV firmware and restrict what configuration and operational 5106 commands can be performed on this guest by the hypervisor. The 5107 policy should be provided by the guest owner and is bound to the 5108 guest and cannot be changed throughout the lifetime of the 5109 guest. The default is 0. 5110 5111 If guest ``policy`` allows sharing the key with another SEV 5112 guest then ``handle`` can be use to provide handle of the guest 5113 from which to share the key. 5114 5115 The ``dh-cert-file`` and ``session-file`` provides the guest 5116 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5117 and session parameters are used for establishing a cryptographic 5118 session with the guest owner to negotiate keys used for 5119 attestation. The file must be encoded in base64. 5120 5121 e.g to launch a SEV guest 5122 5123 .. parsed-literal:: 5124 5125 # |qemu_system_x86| \\ 5126 ...... \\ 5127 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5128 -machine ...,memory-encryption=sev0 \\ 5129 ..... 5130 5131 ``-object authz-simple,id=id,identity=string`` 5132 Create an authorization object that will control access to 5133 network services. 5134 5135 The ``identity`` parameter is identifies the user and its format 5136 depends on the network service that authorization object is 5137 associated with. For authorizing based on TLS x509 certificates, 5138 the identity must be the x509 distinguished name. Note that care 5139 must be taken to escape any commas in the distinguished name. 5140 5141 An example authorization object to validate a x509 distinguished 5142 name would look like: 5143 5144 .. parsed-literal:: 5145 5146 # |qemu_system| \\ 5147 ... \\ 5148 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5149 ... 5150 5151 Note the use of quotes due to the x509 distinguished name 5152 containing whitespace, and escaping of ','. 5153 5154 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5155 Create an authorization object that will control access to 5156 network services. 5157 5158 The ``filename`` parameter is the fully qualified path to a file 5159 containing the access control list rules in JSON format. 5160 5161 An example set of rules that match against SASL usernames might 5162 look like: 5163 5164 :: 5165 5166 { 5167 "rules": [ 5168 { "match": "fred", "policy": "allow", "format": "exact" }, 5169 { "match": "bob", "policy": "allow", "format": "exact" }, 5170 { "match": "danb", "policy": "deny", "format": "glob" }, 5171 { "match": "dan*", "policy": "allow", "format": "exact" }, 5172 ], 5173 "policy": "deny" 5174 } 5175 5176 When checking access the object will iterate over all the rules 5177 and the first rule to match will have its ``policy`` value 5178 returned as the result. If no rules match, then the default 5179 ``policy`` value is returned. 5180 5181 The rules can either be an exact string match, or they can use 5182 the simple UNIX glob pattern matching to allow wildcards to be 5183 used. 5184 5185 If ``refresh`` is set to true the file will be monitored and 5186 automatically reloaded whenever its content changes. 5187 5188 As with the ``authz-simple`` object, the format of the identity 5189 strings being matched depends on the network service, but is 5190 usually a TLS x509 distinguished name, or a SASL username. 5191 5192 An example authorization object to validate a SASL username 5193 would look like: 5194 5195 .. parsed-literal:: 5196 5197 # |qemu_system| \\ 5198 ... \\ 5199 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5200 ... 5201 5202 ``-object authz-pam,id=id,service=string`` 5203 Create an authorization object that will control access to 5204 network services. 5205 5206 The ``service`` parameter provides the name of a PAM service to 5207 use for authorization. It requires that a file 5208 ``/etc/pam.d/service`` exist to provide the configuration for 5209 the ``account`` subsystem. 5210 5211 An example authorization object to validate a TLS x509 5212 distinguished name would look like: 5213 5214 .. parsed-literal:: 5215 5216 # |qemu_system| \\ 5217 ... \\ 5218 -object authz-pam,id=auth0,service=qemu-vnc \\ 5219 ... 5220 5221 There would then be a corresponding config file for PAM at 5222 ``/etc/pam.d/qemu-vnc`` that contains: 5223 5224 :: 5225 5226 account requisite pam_listfile.so item=user sense=allow \ 5227 file=/etc/qemu/vnc.allow 5228 5229 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5230 of x509 distingished names that are permitted access 5231 5232 :: 5233 5234 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5235 5236 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5237 Creates a dedicated event loop thread that devices can be 5238 assigned to. This is known as an IOThread. By default device 5239 emulation happens in vCPU threads or the main event loop thread. 5240 This can become a scalability bottleneck. IOThreads allow device 5241 emulation and I/O to run on other host CPUs. 5242 5243 The ``id`` parameter is a unique ID that will be used to 5244 reference this IOThread from ``-device ...,iothread=id``. 5245 Multiple devices can be assigned to an IOThread. Note that not 5246 all devices support an ``iothread`` parameter. 5247 5248 The ``query-iothreads`` QMP command lists IOThreads and reports 5249 their thread IDs so that the user can configure host CPU 5250 pinning/affinity. 5251 5252 IOThreads use an adaptive polling algorithm to reduce event loop 5253 latency. Instead of entering a blocking system call to monitor 5254 file descriptors and then pay the cost of being woken up when an 5255 event occurs, the polling algorithm spins waiting for events for 5256 a short time. The algorithm's default parameters are suitable 5257 for many cases but can be adjusted based on knowledge of the 5258 workload and/or host device latency. 5259 5260 The ``poll-max-ns`` parameter is the maximum number of 5261 nanoseconds to busy wait for events. Polling can be disabled by 5262 setting this value to 0. 5263 5264 The ``poll-grow`` parameter is the multiplier used to increase 5265 the polling time when the algorithm detects it is missing events 5266 due to not polling long enough. 5267 5268 The ``poll-shrink`` parameter is the divisor used to decrease 5269 the polling time when the algorithm detects it is spending too 5270 long polling without encountering events. 5271 5272 The polling parameters can be modified at run-time using the 5273 ``qom-set`` command (where ``iothread1`` is the IOThread's 5274 ``id``): 5275 5276 :: 5277 5278 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5279ERST 5280 5281 5282HXCOMM This is the last statement. Insert new options before this line! 5283 5284#undef DEF 5285#undef DEFHEADING 5286#undef ARCHHEADING 5287
