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, 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 QEMU_ARCH_ALL) 40SRST 41``-machine [type=]name[,prop=value[,...]]`` 42 Select the emulated machine by name. Use ``-machine help`` to list 43 available machines. 44 45 For architectures which aim to support live migration compatibility 46 across releases, each release will introduce a new versioned machine 47 type. For example, the 2.8.0 release introduced machine types 48 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 49 50 To allow live migration of guests from QEMU version 2.8.0, to QEMU 51 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 52 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 53 skip multiple intermediate releases when upgrading, new releases of 54 QEMU will support machine types from many previous versions. 55 56 Supported machine properties are: 57 58 ``accel=accels1[:accels2[:...]]`` 59 This is used to enable an accelerator. Depending on the target 60 architecture, kvm, xen, hax, hvf, whpx or tcg can be available. 61 By default, tcg is used. If there is more than one accelerator 62 specified, the next one is used if the previous one fails to 63 initialize. 64 65 ``vmport=on|off|auto`` 66 Enables emulation of VMWare IO port, for vmmouse etc. auto says 67 to select the value based on accel. For accel=xen the default is 68 off otherwise the default is on. 69 70 ``dump-guest-core=on|off`` 71 Include guest memory in a core dump. The default is on. 72 73 ``mem-merge=on|off`` 74 Enables or disables memory merge support. This feature, when 75 supported by the host, de-duplicates identical memory pages 76 among VMs instances (enabled by default). 77 78 ``aes-key-wrap=on|off`` 79 Enables or disables AES key wrapping support on s390-ccw hosts. 80 This feature controls whether AES wrapping keys will be created 81 to allow execution of AES cryptographic functions. The default 82 is on. 83 84 ``dea-key-wrap=on|off`` 85 Enables or disables DEA key wrapping support on s390-ccw hosts. 86 This feature controls whether DEA wrapping keys will be created 87 to allow execution of DEA cryptographic functions. The default 88 is on. 89 90 ``nvdimm=on|off`` 91 Enables or disables NVDIMM support. The default is off. 92 93 ``memory-encryption=`` 94 Memory encryption object to use. The default is none. 95 96 ``hmat=on|off`` 97 Enables or disables ACPI Heterogeneous Memory Attribute Table 98 (HMAT) support. The default is off. 99ERST 100 101HXCOMM Deprecated by -machine 102DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL) 103 104DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 105 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 106SRST 107``-cpu model`` 108 Select CPU model (``-cpu help`` for list and additional feature 109 selection) 110ERST 111 112DEF("accel", HAS_ARG, QEMU_OPTION_accel, 113 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 114 " select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n" 115 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 116 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 117 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 118 " split-wx=on|off (enable TCG split w^x mapping)\n" 119 " tb-size=n (TCG translation block cache size)\n" 120 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 121SRST 122``-accel name[,prop=value[,...]]`` 123 This is used to enable an accelerator. Depending on the target 124 architecture, kvm, xen, hax, hvf, whpx or tcg can be available. By 125 default, tcg is used. If there is more than one accelerator 126 specified, the next one is used if the previous one fails to 127 initialize. 128 129 ``igd-passthru=on|off`` 130 When Xen is in use, this option controls whether Intel 131 integrated graphics devices can be passed through to the guest 132 (default=off) 133 134 ``kernel-irqchip=on|off|split`` 135 Controls KVM in-kernel irqchip support. The default is full 136 acceleration of the interrupt controllers. On x86, split irqchip 137 reduces the kernel attack surface, at a performance cost for 138 non-MSI interrupts. Disabling the in-kernel irqchip completely 139 is not recommended except for debugging purposes. 140 141 ``kvm-shadow-mem=size`` 142 Defines the size of the KVM shadow MMU. 143 144 ``split-wx=on|off`` 145 Controls the use of split w^x mapping for the TCG code generation 146 buffer. Some operating systems require this to be enabled, and in 147 such a case this will default on. On other operating systems, this 148 will default off, but one may enable this for testing or debugging. 149 150 ``tb-size=n`` 151 Controls the size (in MiB) of the TCG translation block cache. 152 153 ``thread=single|multi`` 154 Controls number of TCG threads. When the TCG is multi-threaded 155 there will be one thread per vCPU therefor taking advantage of 156 additional host cores. The default is to enable multi-threading 157 where both the back-end and front-ends support it and no 158 incompatible TCG features have been enabled (e.g. 159 icount/replay). 160ERST 161 162DEF("smp", HAS_ARG, QEMU_OPTION_smp, 163 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 164 " set the number of CPUs to 'n' [default=1]\n" 165 " maxcpus= maximum number of total cpus, including\n" 166 " offline CPUs for hotplug, etc\n" 167 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 168 " threads= number of threads on one CPU core\n" 169 " dies= number of CPU dies on one socket (for PC only)\n" 170 " sockets= number of discrete sockets in the system\n", 171 QEMU_ARCH_ALL) 172SRST 173``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]`` 174 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs 175 are supported. On Sparc32 target, Linux limits the number of usable 176 CPUs to 4. For the PC target, the number of cores per die, the 177 number of threads per cores, the number of dies per packages and the 178 total number of sockets can be specified. Missing values will be 179 computed. If any on the three values is given, the total number of 180 CPUs n can be omitted. maxcpus specifies the maximum number of 181 hotpluggable CPUs. 182ERST 183 184DEF("numa", HAS_ARG, QEMU_OPTION_numa, 185 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 186 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 187 "-numa dist,src=source,dst=destination,val=distance\n" 188 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 189 "-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" 190 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 191 QEMU_ARCH_ALL) 192SRST 193``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 194 \ 195``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 196 \ 197``-numa dist,src=source,dst=destination,val=distance`` 198 \ 199``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 200 \ 201``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 202 \ 203``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 204 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 205 distance from a source node to a destination node. Set the ACPI 206 Heterogeneous Memory Attributes for the given nodes. 207 208 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 209 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 210 contiguous range of CPU indexes (or a single VCPU if lastcpu is 211 omitted). A non-contiguous set of VCPUs can be represented by 212 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 213 omitted on all nodes, VCPUs are automatically split between them. 214 215 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 216 NUMA node: 217 218 :: 219 220 -numa node,cpus=0-2,cpus=5 221 222 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 223 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 224 assign CPU objects to a node using topology layout properties of 225 CPU. The set of properties is machine specific, and depends on used 226 machine type/'\ ``smp``\ ' options. It could be queried with 227 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 228 property specifies node to which CPU object will be assigned, it's 229 required for node to be declared with '\ ``node``\ ' option before 230 it's used with '\ ``cpu``\ ' option. 231 232 For example: 233 234 :: 235 236 -M pc \ 237 -smp 1,sockets=2,maxcpus=2 \ 238 -numa node,nodeid=0 -numa node,nodeid=1 \ 239 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 240 241 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 242 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 243 a given memory backend device to a node. If '\ ``mem``\ ' and 244 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 245 246 247 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 248 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 249 use it. 250 251 '\ ``initiator``\ ' is an additional option that points to an 252 initiator NUMA node that has best performance (the lowest latency or 253 largest bandwidth) to this NUMA node. Note that this option can be 254 set only when the machine property 'hmat' is set to 'on'. 255 256 Following example creates a machine with 2 NUMA nodes, node 0 has 257 CPU. node 1 has only memory, and its initiator is node 0. Note that 258 because node 0 has CPU, by default the initiator of node 0 is itself 259 and must be itself. 260 261 :: 262 263 -machine hmat=on \ 264 -m 2G,slots=2,maxmem=4G \ 265 -object memory-backend-ram,size=1G,id=m0 \ 266 -object memory-backend-ram,size=1G,id=m1 \ 267 -numa node,nodeid=0,memdev=m0 \ 268 -numa node,nodeid=1,memdev=m1,initiator=0 \ 269 -smp 2,sockets=2,maxcpus=2 \ 270 -numa cpu,node-id=0,socket-id=0 \ 271 -numa cpu,node-id=0,socket-id=1 272 273 source and destination are NUMA node IDs. distance is the NUMA 274 distance from source to destination. The distance from a node to 275 itself is always 10. If any pair of nodes is given a distance, then 276 all pairs must be given distances. Although, when distances are only 277 given in one direction for each pair of nodes, then the distances in 278 the opposite directions are assumed to be the same. If, however, an 279 asymmetrical pair of distances is given for even one node pair, then 280 all node pairs must be provided distance values for both directions, 281 even when they are symmetrical. When a node is unreachable from 282 another node, set the pair's distance to 255. 283 284 Note that the -``numa`` option doesn't allocate any of the specified 285 resources, it just assigns existing resources to NUMA nodes. This 286 means that one still has to use the ``-m``, ``-smp`` options to 287 allocate RAM and VCPUs respectively. 288 289 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 290 Information between initiator and target NUMA nodes in ACPI 291 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 292 create memory requests, usually it has one or more processors. 293 Target NUMA node contains addressable memory. 294 295 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 296 the memory hierarchy of the target NUMA node: if hierarchy is 297 'memory', the structure represents the memory performance; if 298 hierarchy is 'first-level\|second-level\|third-level', this 299 structure represents aggregated performance of memory side caches 300 for each domain. type of 'data-type' is type of data represented by 301 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 302 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 303 the target memory; if 'hierarchy' is 304 'first-level\|second-level\|third-level', 'data-type' is 305 'access\|read\|write' hit latency or 'access\|read\|write' hit 306 bandwidth of the target memory side cache. 307 308 lat is latency value in nanoseconds. bw is bandwidth value, the 309 possible value and units are NUM[M\|G\|T], mean that the bandwidth 310 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 311 used suffix). Note that if latency or bandwidth value is 0, means 312 the corresponding latency or bandwidth information is not provided. 313 314 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 315 belongs. size is the size of memory side cache in bytes. level is 316 the cache level described in this structure, note that the cache 317 level 0 should not be used with '\ ``hmat-cache``\ ' option. 318 associativity is the cache associativity, the possible value is 319 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 320 is the write policy. line is the cache Line size in bytes. 321 322 For example, the following options describe 2 NUMA nodes. Node 0 has 323 2 cpus and a ram, node 1 has only a ram. The processors in node 0 324 access memory in node 0 with access-latency 5 nanoseconds, 325 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 326 memory in NUMA node 1 with access-latency 10 nanoseconds, 327 access-bandwidth is 100 MB/s. And for memory side cache information, 328 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 329 policy is write-back, the cache Line size is 8 bytes: 330 331 :: 332 333 -machine hmat=on \ 334 -m 2G \ 335 -object memory-backend-ram,size=1G,id=m0 \ 336 -object memory-backend-ram,size=1G,id=m1 \ 337 -smp 2 \ 338 -numa node,nodeid=0,memdev=m0 \ 339 -numa node,nodeid=1,memdev=m1,initiator=0 \ 340 -numa cpu,node-id=0,socket-id=0 \ 341 -numa cpu,node-id=0,socket-id=1 \ 342 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 343 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 344 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 345 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 346 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 347 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 348ERST 349 350DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 351 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 352 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 353SRST 354``-add-fd fd=fd,set=set[,opaque=opaque]`` 355 Add a file descriptor to an fd set. Valid options are: 356 357 ``fd=fd`` 358 This option defines the file descriptor of which a duplicate is 359 added to fd set. The file descriptor cannot be stdin, stdout, or 360 stderr. 361 362 ``set=set`` 363 This option defines the ID of the fd set to add the file 364 descriptor to. 365 366 ``opaque=opaque`` 367 This option defines a free-form string that can be used to 368 describe fd. 369 370 You can open an image using pre-opened file descriptors from an fd 371 set: 372 373 .. parsed-literal:: 374 375 |qemu_system| \\ 376 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 377 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 378 -drive file=/dev/fdset/2,index=0,media=disk 379ERST 380 381DEF("set", HAS_ARG, QEMU_OPTION_set, 382 "-set group.id.arg=value\n" 383 " set <arg> parameter for item <id> of type <group>\n" 384 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 385SRST 386``-set group.id.arg=value`` 387 Set parameter arg for item id of type group 388ERST 389 390DEF("global", HAS_ARG, QEMU_OPTION_global, 391 "-global driver.property=value\n" 392 "-global driver=driver,property=property,value=value\n" 393 " set a global default for a driver property\n", 394 QEMU_ARCH_ALL) 395SRST 396``-global driver.prop=value`` 397 \ 398``-global driver=driver,property=property,value=value`` 399 Set default value of driver's property prop to value, e.g.: 400 401 .. parsed-literal:: 402 403 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 404 405 In particular, you can use this to set driver properties for devices 406 which are created automatically by the machine model. To create a 407 device which is not created automatically and set properties on it, 408 use -``device``. 409 410 -global driver.prop=value is shorthand for -global 411 driver=driver,property=prop,value=value. The longhand syntax works 412 even when driver contains a dot. 413ERST 414 415DEF("boot", HAS_ARG, QEMU_OPTION_boot, 416 "-boot [order=drives][,once=drives][,menu=on|off]\n" 417 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 418 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 419 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 420 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 421 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 422 QEMU_ARCH_ALL) 423SRST 424``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 425 Specify boot order drives as a string of drive letters. Valid drive 426 letters depend on the target architecture. The x86 PC uses: a, b 427 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 428 (Etherboot from network adapter 1-4), hard disk boot is the default. 429 To apply a particular boot order only on the first startup, specify 430 it via ``once``. Note that the ``order`` or ``once`` parameter 431 should not be used together with the ``bootindex`` property of 432 devices, since the firmware implementations normally do not support 433 both at the same time. 434 435 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 436 as firmware/BIOS supports them. The default is non-interactive boot. 437 438 A splash picture could be passed to bios, enabling user to show it 439 as logo, when option splash=sp\_name is given and menu=on, If 440 firmware/BIOS supports them. Currently Seabios for X86 system 441 support it. limitation: The splash file could be a jpeg file or a 442 BMP file in 24 BPP format(true color). The resolution should be 443 supported by the SVGA mode, so the recommended is 320x240, 640x480, 444 800x640. 445 446 A timeout could be passed to bios, guest will pause for rb\_timeout 447 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 448 not reboot, qemu passes '-1' to bios by default. Currently Seabios 449 for X86 system support it. 450 451 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 452 it. This only effects when boot priority is changed by bootindex 453 options. The default is non-strict boot. 454 455 .. parsed-literal:: 456 457 # try to boot from network first, then from hard disk 458 |qemu_system_x86| -boot order=nc 459 # boot from CD-ROM first, switch back to default order after reboot 460 |qemu_system_x86| -boot once=d 461 # boot with a splash picture for 5 seconds. 462 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 463 464 Note: The legacy format '-boot drives' is still supported but its 465 use is discouraged as it may be removed from future versions. 466ERST 467 468DEF("m", HAS_ARG, QEMU_OPTION_m, 469 "-m [size=]megs[,slots=n,maxmem=size]\n" 470 " configure guest RAM\n" 471 " size: initial amount of guest memory\n" 472 " slots: number of hotplug slots (default: none)\n" 473 " maxmem: maximum amount of guest memory (default: none)\n" 474 "NOTE: Some architectures might enforce a specific granularity\n", 475 QEMU_ARCH_ALL) 476SRST 477``-m [size=]megs[,slots=n,maxmem=size]`` 478 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 479 Optionally, a suffix of "M" or "G" can be used to signify a value in 480 megabytes or gigabytes respectively. Optional pair slots, maxmem 481 could be used to set amount of hotpluggable memory slots and maximum 482 amount of memory. Note that maxmem must be aligned to the page size. 483 484 For example, the following command-line sets the guest startup RAM 485 size to 1GB, creates 3 slots to hotplug additional memory and sets 486 the maximum memory the guest can reach to 4GB: 487 488 .. parsed-literal:: 489 490 |qemu_system| -m 1G,slots=3,maxmem=4G 491 492 If slots and maxmem are not specified, memory hotplug won't be 493 enabled and the guest startup RAM will never increase. 494ERST 495 496DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 497 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 498SRST 499``-mem-path path`` 500 Allocate guest RAM from a temporarily created file in path. 501ERST 502 503DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 504 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 505 QEMU_ARCH_ALL) 506SRST 507``-mem-prealloc`` 508 Preallocate memory when using -mem-path. 509ERST 510 511DEF("k", HAS_ARG, QEMU_OPTION_k, 512 "-k language use keyboard layout (for example 'fr' for French)\n", 513 QEMU_ARCH_ALL) 514SRST 515``-k language`` 516 Use keyboard layout language (for example ``fr`` for French). This 517 option is only needed where it is not easy to get raw PC keycodes 518 (e.g. on Macs, with some X11 servers or with a VNC or curses 519 display). You don't normally need to use it on PC/Linux or 520 PC/Windows hosts. 521 522 The available layouts are: 523 524 :: 525 526 ar de-ch es fo fr-ca hu ja mk no pt-br sv 527 da en-gb et fr fr-ch is lt nl pl ru th 528 de en-us fi fr-be hr it lv nl-be pt sl tr 529 530 The default is ``en-us``. 531ERST 532 533 534HXCOMM Deprecated by -audiodev 535DEF("audio-help", 0, QEMU_OPTION_audio_help, 536 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 537 QEMU_ARCH_ALL) 538SRST 539``-audio-help`` 540 Will show the -audiodev equivalent of the currently specified 541 (deprecated) environment variables. 542ERST 543 544DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 545 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 546 " specifies the audio backend to use\n" 547 " id= identifier of the backend\n" 548 " timer-period= timer period in microseconds\n" 549 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 550 " in|out.fixed-settings= use fixed settings for host audio\n" 551 " in|out.frequency= frequency to use with fixed settings\n" 552 " in|out.channels= number of channels to use with fixed settings\n" 553 " in|out.format= sample format to use with fixed settings\n" 554 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 555 " in|out.voices= number of voices to use\n" 556 " in|out.buffer-length= length of buffer in microseconds\n" 557 "-audiodev none,id=id,[,prop[=value][,...]]\n" 558 " dummy driver that discards all output\n" 559#ifdef CONFIG_AUDIO_ALSA 560 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 561 " in|out.dev= name of the audio device to use\n" 562 " in|out.period-length= length of period in microseconds\n" 563 " in|out.try-poll= attempt to use poll mode\n" 564 " threshold= threshold (in microseconds) when playback starts\n" 565#endif 566#ifdef CONFIG_AUDIO_COREAUDIO 567 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 568 " in|out.buffer-count= number of buffers\n" 569#endif 570#ifdef CONFIG_AUDIO_DSOUND 571 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 572 " latency= add extra latency to playback in microseconds\n" 573#endif 574#ifdef CONFIG_AUDIO_OSS 575 "-audiodev oss,id=id[,prop[=value][,...]]\n" 576 " in|out.dev= path of the audio device to use\n" 577 " in|out.buffer-count= number of buffers\n" 578 " in|out.try-poll= attempt to use poll mode\n" 579 " try-mmap= try using memory mapped access\n" 580 " exclusive= open device in exclusive mode\n" 581 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 582#endif 583#ifdef CONFIG_AUDIO_PA 584 "-audiodev pa,id=id[,prop[=value][,...]]\n" 585 " server= PulseAudio server address\n" 586 " in|out.name= source/sink device name\n" 587 " in|out.latency= desired latency in microseconds\n" 588#endif 589#ifdef CONFIG_AUDIO_SDL 590 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 591 " in|out.buffer-count= number of buffers\n" 592#endif 593#ifdef CONFIG_SPICE 594 "-audiodev spice,id=id[,prop[=value][,...]]\n" 595#endif 596 "-audiodev wav,id=id[,prop[=value][,...]]\n" 597 " path= path of wav file to record\n", 598 QEMU_ARCH_ALL) 599SRST 600``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 601 Adds a new audio backend driver identified by id. There are global 602 and driver specific properties. Some values can be set differently 603 for input and output, they're marked with ``in|out.``. You can set 604 the input's property with ``in.prop`` and the output's property with 605 ``out.prop``. For example: 606 607 :: 608 609 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 610 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 611 612 NOTE: parameter validation is known to be incomplete, in many cases 613 specifying an invalid option causes QEMU to print an error message 614 and continue emulation without sound. 615 616 Valid global options are: 617 618 ``id=identifier`` 619 Identifies the audio backend. 620 621 ``timer-period=period`` 622 Sets the timer period used by the audio subsystem in 623 microseconds. Default is 10000 (10 ms). 624 625 ``in|out.mixing-engine=on|off`` 626 Use QEMU's mixing engine to mix all streams inside QEMU and 627 convert audio formats when not supported by the backend. When 628 off, fixed-settings must be off too. Note that disabling this 629 option means that the selected backend must support multiple 630 streams and the audio formats used by the virtual cards, 631 otherwise you'll get no sound. It's not recommended to disable 632 this option unless you want to use 5.1 or 7.1 audio, as mixing 633 engine only supports mono and stereo audio. Default is on. 634 635 ``in|out.fixed-settings=on|off`` 636 Use fixed settings for host audio. When off, it will change 637 based on how the guest opens the sound card. In this case you 638 must not specify frequency, channels or format. Default is on. 639 640 ``in|out.frequency=frequency`` 641 Specify the frequency to use when using fixed-settings. Default 642 is 44100Hz. 643 644 ``in|out.channels=channels`` 645 Specify the number of channels to use when using fixed-settings. 646 Default is 2 (stereo). 647 648 ``in|out.format=format`` 649 Specify the sample format to use when using fixed-settings. 650 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 651 ``u32``, ``f32``. Default is ``s16``. 652 653 ``in|out.voices=voices`` 654 Specify the number of voices to use. Default is 1. 655 656 ``in|out.buffer-length=usecs`` 657 Sets the size of the buffer in microseconds. 658 659``-audiodev none,id=id[,prop[=value][,...]]`` 660 Creates a dummy backend that discards all outputs. This backend has 661 no backend specific properties. 662 663``-audiodev alsa,id=id[,prop[=value][,...]]`` 664 Creates backend using the ALSA. This backend is only available on 665 Linux. 666 667 ALSA specific options are: 668 669 ``in|out.dev=device`` 670 Specify the ALSA device to use for input and/or output. Default 671 is ``default``. 672 673 ``in|out.period-length=usecs`` 674 Sets the period length in microseconds. 675 676 ``in|out.try-poll=on|off`` 677 Attempt to use poll mode with the device. Default is on. 678 679 ``threshold=threshold`` 680 Threshold (in microseconds) when playback starts. Default is 0. 681 682``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 683 Creates a backend using Apple's Core Audio. This backend is only 684 available on Mac OS and only supports playback. 685 686 Core Audio specific options are: 687 688 ``in|out.buffer-count=count`` 689 Sets the count of the buffers. 690 691``-audiodev dsound,id=id[,prop[=value][,...]]`` 692 Creates a backend using Microsoft's DirectSound. This backend is 693 only available on Windows and only supports playback. 694 695 DirectSound specific options are: 696 697 ``latency=usecs`` 698 Add extra usecs microseconds latency to playback. Default is 699 10000 (10 ms). 700 701``-audiodev oss,id=id[,prop[=value][,...]]`` 702 Creates a backend using OSS. This backend is available on most 703 Unix-like systems. 704 705 OSS specific options are: 706 707 ``in|out.dev=device`` 708 Specify the file name of the OSS device to use. Default is 709 ``/dev/dsp``. 710 711 ``in|out.buffer-count=count`` 712 Sets the count of the buffers. 713 714 ``in|out.try-poll=on|of`` 715 Attempt to use poll mode with the device. Default is on. 716 717 ``try-mmap=on|off`` 718 Try using memory mapped device access. Default is off. 719 720 ``exclusive=on|off`` 721 Open the device in exclusive mode (vmix won't work in this 722 case). Default is off. 723 724 ``dsp-policy=policy`` 725 Sets the timing policy (between 0 and 10, where smaller number 726 means smaller latency but higher CPU usage). Use -1 to use 727 buffer sizes specified by ``buffer`` and ``buffer-count``. This 728 option is ignored if you do not have OSS 4. Default is 5. 729 730``-audiodev pa,id=id[,prop[=value][,...]]`` 731 Creates a backend using PulseAudio. This backend is available on 732 most systems. 733 734 PulseAudio specific options are: 735 736 ``server=server`` 737 Sets the PulseAudio server to connect to. 738 739 ``in|out.name=sink`` 740 Use the specified source/sink for recording/playback. 741 742 ``in|out.latency=usecs`` 743 Desired latency in microseconds. The PulseAudio server will try 744 to honor this value but actual latencies may be lower or higher. 745 746``-audiodev sdl,id=id[,prop[=value][,...]]`` 747 Creates a backend using SDL. This backend is available on most 748 systems, but you should use your platform's native backend if 749 possible. 750 751 SDL specific options are: 752 753 ``in|out.buffer-count=count`` 754 Sets the count of the buffers. 755 756``-audiodev spice,id=id[,prop[=value][,...]]`` 757 Creates a backend that sends audio through SPICE. This backend 758 requires ``-spice`` and automatically selected in that case, so 759 usually you can ignore this option. This backend has no backend 760 specific properties. 761 762``-audiodev wav,id=id[,prop[=value][,...]]`` 763 Creates a backend that writes audio to a WAV file. 764 765 Backend specific options are: 766 767 ``path=path`` 768 Write recorded audio into the specified file. Default is 769 ``qemu.wav``. 770ERST 771 772DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 773 "-soundhw c1,... enable audio support\n" 774 " and only specified sound cards (comma separated list)\n" 775 " use '-soundhw help' to get the list of supported cards\n" 776 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 777SRST 778``-soundhw card1[,card2,...] or -soundhw all`` 779 Enable audio and selected sound hardware. Use 'help' to print all 780 available sound hardware. For example: 781 782 .. parsed-literal:: 783 784 |qemu_system_x86| -soundhw sb16,adlib disk.img 785 |qemu_system_x86| -soundhw es1370 disk.img 786 |qemu_system_x86| -soundhw ac97 disk.img 787 |qemu_system_x86| -soundhw hda disk.img 788 |qemu_system_x86| -soundhw all disk.img 789 |qemu_system_x86| -soundhw help 790 791 Note that Linux's i810\_audio OSS kernel (for AC97) module might 792 require manually specifying clocking. 793 794 :: 795 796 modprobe i810_audio clocking=48000 797ERST 798 799DEF("device", HAS_ARG, QEMU_OPTION_device, 800 "-device driver[,prop[=value][,...]]\n" 801 " add device (based on driver)\n" 802 " prop=value,... sets driver properties\n" 803 " use '-device help' to print all possible drivers\n" 804 " use '-device driver,help' to print all possible properties\n", 805 QEMU_ARCH_ALL) 806SRST 807``-device driver[,prop[=value][,...]]`` 808 Add device driver. prop=value sets driver properties. Valid 809 properties depend on the driver. To get help on possible drivers and 810 properties, use ``-device help`` and ``-device driver,help``. 811 812 Some drivers are: 813 814``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 815 Add an IPMI BMC. This is a simulation of a hardware management 816 interface processor that normally sits on a system. It provides a 817 watchdog and the ability to reset and power control the system. You 818 need to connect this to an IPMI interface to make it useful 819 820 The IPMI slave address to use for the BMC. The default is 0x20. This 821 address is the BMC's address on the I2C network of management 822 controllers. If you don't know what this means, it is safe to ignore 823 it. 824 825 ``id=id`` 826 The BMC id for interfaces to use this device. 827 828 ``slave_addr=val`` 829 Define slave address to use for the BMC. The default is 0x20. 830 831 ``sdrfile=file`` 832 file containing raw Sensor Data Records (SDR) data. The default 833 is none. 834 835 ``fruareasize=val`` 836 size of a Field Replaceable Unit (FRU) area. The default is 837 1024. 838 839 ``frudatafile=file`` 840 file containing raw Field Replaceable Unit (FRU) inventory data. 841 The default is none. 842 843 ``guid=uuid`` 844 value for the GUID for the BMC, in standard UUID format. If this 845 is set, get "Get GUID" command to the BMC will return it. 846 Otherwise "Get GUID" will return an error. 847 848``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 849 Add a connection to an external IPMI BMC simulator. Instead of 850 locally emulating the BMC like the above item, instead connect to an 851 external entity that provides the IPMI services. 852 853 A connection is made to an external BMC simulator. If you do this, 854 it is strongly recommended that you use the "reconnect=" chardev 855 option to reconnect to the simulator if the connection is lost. Note 856 that if this is not used carefully, it can be a security issue, as 857 the interface has the ability to send resets, NMIs, and power off 858 the VM. It's best if QEMU makes a connection to an external 859 simulator running on a secure port on localhost, so neither the 860 simulator nor QEMU is exposed to any outside network. 861 862 See the "lanserv/README.vm" file in the OpenIPMI library for more 863 details on the external interface. 864 865``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 866 Add a KCS IPMI interafce on the ISA bus. This also adds a 867 corresponding ACPI and SMBIOS entries, if appropriate. 868 869 ``bmc=id`` 870 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 871 above. 872 873 ``ioport=val`` 874 Define the I/O address of the interface. The default is 0xca0 875 for KCS. 876 877 ``irq=val`` 878 Define the interrupt to use. The default is 5. To disable 879 interrupts, set this to 0. 880 881``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 882 Like the KCS interface, but defines a BT interface. The default port 883 is 0xe4 and the default interrupt is 5. 884 885``-device pci-ipmi-kcs,bmc=id`` 886 Add a KCS IPMI interafce on the PCI bus. 887 888 ``bmc=id`` 889 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 890 891``-device pci-ipmi-bt,bmc=id`` 892 Like the KCS interface, but defines a BT interface on the PCI bus. 893ERST 894 895DEF("name", HAS_ARG, QEMU_OPTION_name, 896 "-name string1[,process=string2][,debug-threads=on|off]\n" 897 " set the name of the guest\n" 898 " string1 sets the window title and string2 the process name\n" 899 " When debug-threads is enabled, individual threads are given a separate name\n" 900 " NOTE: The thread names are for debugging and not a stable API.\n", 901 QEMU_ARCH_ALL) 902SRST 903``-name name`` 904 Sets the name of the guest. This name will be displayed in the SDL 905 window caption. The name will also be used for the VNC server. Also 906 optionally set the top visible process name in Linux. Naming of 907 individual threads can also be enabled on Linux to aid debugging. 908ERST 909 910DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 911 "-uuid %08x-%04x-%04x-%04x-%012x\n" 912 " specify machine UUID\n", QEMU_ARCH_ALL) 913SRST 914``-uuid uuid`` 915 Set system UUID. 916ERST 917 918DEFHEADING() 919 920DEFHEADING(Block device options:) 921 922DEF("fda", HAS_ARG, QEMU_OPTION_fda, 923 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 924DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 925SRST 926``-fda file`` 927 \ 928``-fdb file`` 929 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 930 the System Emulation Users Guide). 931ERST 932 933DEF("hda", HAS_ARG, QEMU_OPTION_hda, 934 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 935DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 936DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 937 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 938DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 939SRST 940``-hda file`` 941 \ 942``-hdb file`` 943 \ 944``-hdc file`` 945 \ 946``-hdd file`` 947 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 948 chapter in the System Emulation Users Guide). 949ERST 950 951DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 952 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 953 QEMU_ARCH_ALL) 954SRST 955``-cdrom file`` 956 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 957 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 958 as filename. 959ERST 960 961DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 962 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 963 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 964 " [,read-only=on|off][,auto-read-only=on|off]\n" 965 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 966 " [,driver specific parameters...]\n" 967 " configure a block backend\n", QEMU_ARCH_ALL) 968SRST 969``-blockdev option[,option[,option[,...]]]`` 970 Define a new block driver node. Some of the options apply to all 971 block drivers, other options are only accepted for a specific block 972 driver. See below for a list of generic options and options for the 973 most common block drivers. 974 975 Options that expect a reference to another node (e.g. ``file``) can 976 be given in two ways. Either you specify the node name of an already 977 existing node (file=node-name), or you define a new node inline, 978 adding options for the referenced node after a dot 979 (file.filename=path,file.aio=native). 980 981 A block driver node created with ``-blockdev`` can be used for a 982 guest device by specifying its node name for the ``drive`` property 983 in a ``-device`` argument that defines a block device. 984 985 ``Valid options for any block driver node:`` 986 ``driver`` 987 Specifies the block driver to use for the given node. 988 989 ``node-name`` 990 This defines the name of the block driver node by which it 991 will be referenced later. The name must be unique, i.e. it 992 must not match the name of a different block driver node, or 993 (if you use ``-drive`` as well) the ID of a drive. 994 995 If no node name is specified, it is automatically generated. 996 The generated node name is not intended to be predictable 997 and changes between QEMU invocations. For the top level, an 998 explicit node name must be specified. 999 1000 ``read-only`` 1001 Open the node read-only. Guest write attempts will fail. 1002 1003 Note that some block drivers support only read-only access, 1004 either generally or in certain configurations. In this case, 1005 the default value ``read-only=off`` does not work and the 1006 option must be specified explicitly. 1007 1008 ``auto-read-only`` 1009 If ``auto-read-only=on`` is set, QEMU may fall back to 1010 read-only usage even when ``read-only=off`` is requested, or 1011 even switch between modes as needed, e.g. depending on 1012 whether the image file is writable or whether a writing user 1013 is attached to the node. 1014 1015 ``force-share`` 1016 Override the image locking system of QEMU by forcing the 1017 node to utilize weaker shared access for permissions where 1018 it would normally request exclusive access. When there is 1019 the potential for multiple instances to have the same file 1020 open (whether this invocation of QEMU is the first or the 1021 second instance), both instances must permit shared access 1022 for the second instance to succeed at opening the file. 1023 1024 Enabling ``force-share=on`` requires ``read-only=on``. 1025 1026 ``cache.direct`` 1027 The host page cache can be avoided with ``cache.direct=on``. 1028 This will attempt to do disk IO directly to the guest's 1029 memory. QEMU may still perform an internal copy of the data. 1030 1031 ``cache.no-flush`` 1032 In case you don't care about data integrity over host 1033 failures, you can use ``cache.no-flush=on``. This option 1034 tells QEMU that it never needs to write any data to the disk 1035 but can instead keep things in cache. If anything goes 1036 wrong, like your host losing power, the disk storage getting 1037 disconnected accidentally, etc. your image will most 1038 probably be rendered unusable. 1039 1040 ``discard=discard`` 1041 discard is one of "ignore" (or "off") or "unmap" (or "on") 1042 and controls whether ``discard`` (also known as ``trim`` or 1043 ``unmap``) requests are ignored or passed to the filesystem. 1044 Some machine types may not support discard requests. 1045 1046 ``detect-zeroes=detect-zeroes`` 1047 detect-zeroes is "off", "on" or "unmap" and enables the 1048 automatic conversion of plain zero writes by the OS to 1049 driver specific optimized zero write commands. You may even 1050 choose "unmap" if discard is set to "unmap" to allow a zero 1051 write to be converted to an ``unmap`` operation. 1052 1053 ``Driver-specific options for file`` 1054 This is the protocol-level block driver for accessing regular 1055 files. 1056 1057 ``filename`` 1058 The path to the image file in the local filesystem 1059 1060 ``aio`` 1061 Specifies the AIO backend (threads/native/io_uring, 1062 default: threads) 1063 1064 ``locking`` 1065 Specifies whether the image file is protected with Linux OFD 1066 / POSIX locks. The default is to use the Linux Open File 1067 Descriptor API if available, otherwise no lock is applied. 1068 (auto/on/off, default: auto) 1069 1070 Example: 1071 1072 :: 1073 1074 -blockdev driver=file,node-name=disk,filename=disk.img 1075 1076 ``Driver-specific options for raw`` 1077 This is the image format block driver for raw images. It is 1078 usually stacked on top of a protocol level block driver such as 1079 ``file``. 1080 1081 ``file`` 1082 Reference to or definition of the data source block driver 1083 node (e.g. a ``file`` driver node) 1084 1085 Example 1: 1086 1087 :: 1088 1089 -blockdev driver=file,node-name=disk_file,filename=disk.img 1090 -blockdev driver=raw,node-name=disk,file=disk_file 1091 1092 Example 2: 1093 1094 :: 1095 1096 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1097 1098 ``Driver-specific options for qcow2`` 1099 This is the image format block driver for qcow2 images. It is 1100 usually stacked on top of a protocol level block driver such as 1101 ``file``. 1102 1103 ``file`` 1104 Reference to or definition of the data source block driver 1105 node (e.g. a ``file`` driver node) 1106 1107 ``backing`` 1108 Reference to or definition of the backing file block device 1109 (default is taken from the image file). It is allowed to 1110 pass ``null`` here in order to disable the default backing 1111 file. 1112 1113 ``lazy-refcounts`` 1114 Whether to enable the lazy refcounts feature (on/off; 1115 default is taken from the image file) 1116 1117 ``cache-size`` 1118 The maximum total size of the L2 table and refcount block 1119 caches in bytes (default: the sum of l2-cache-size and 1120 refcount-cache-size) 1121 1122 ``l2-cache-size`` 1123 The maximum size of the L2 table cache in bytes (default: if 1124 cache-size is not specified - 32M on Linux platforms, and 8M 1125 on non-Linux platforms; otherwise, as large as possible 1126 within the cache-size, while permitting the requested or the 1127 minimal refcount cache size) 1128 1129 ``refcount-cache-size`` 1130 The maximum size of the refcount block cache in bytes 1131 (default: 4 times the cluster size; or if cache-size is 1132 specified, the part of it which is not used for the L2 1133 cache) 1134 1135 ``cache-clean-interval`` 1136 Clean unused entries in the L2 and refcount caches. The 1137 interval is in seconds. The default value is 600 on 1138 supporting platforms, and 0 on other platforms. Setting it 1139 to 0 disables this feature. 1140 1141 ``pass-discard-request`` 1142 Whether discard requests to the qcow2 device should be 1143 forwarded to the data source (on/off; default: on if 1144 discard=unmap is specified, off otherwise) 1145 1146 ``pass-discard-snapshot`` 1147 Whether discard requests for the data source should be 1148 issued when a snapshot operation (e.g. deleting a snapshot) 1149 frees clusters in the qcow2 file (on/off; default: on) 1150 1151 ``pass-discard-other`` 1152 Whether discard requests for the data source should be 1153 issued on other occasions where a cluster gets freed 1154 (on/off; default: off) 1155 1156 ``overlap-check`` 1157 Which overlap checks to perform for writes to the image 1158 (none/constant/cached/all; default: cached). For details or 1159 finer granularity control refer to the QAPI documentation of 1160 ``blockdev-add``. 1161 1162 Example 1: 1163 1164 :: 1165 1166 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1167 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1168 1169 Example 2: 1170 1171 :: 1172 1173 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1174 1175 ``Driver-specific options for other drivers`` 1176 Please refer to the QAPI documentation of the ``blockdev-add`` 1177 QMP command. 1178ERST 1179 1180DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1181 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1182 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1183 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1184 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1185 " [,aio=threads|native|io_uring]\n" 1186 " [,readonly=on|off][,copy-on-read=on|off]\n" 1187 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1188 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1189 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1190 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1191 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1192 " [[,iops_size=is]]\n" 1193 " [[,group=g]]\n" 1194 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1195SRST 1196``-drive option[,option[,option[,...]]]`` 1197 Define a new drive. This includes creating a block driver node (the 1198 backend) as well as a guest device, and is mostly a shortcut for 1199 defining the corresponding ``-blockdev`` and ``-device`` options. 1200 1201 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1202 In addition, it knows the following options: 1203 1204 ``file=file`` 1205 This option defines which disk image (see the :ref:`disk images` 1206 chapter in the System Emulation Users Guide) to use with this drive. 1207 If the filename contains comma, you must double it (for instance, 1208 "file=my,,file" to use file "my,file"). 1209 1210 Special files such as iSCSI devices can be specified using 1211 protocol specific URLs. See the section for "Device URL Syntax" 1212 for more information. 1213 1214 ``if=interface`` 1215 This option defines on which type on interface the drive is 1216 connected. Available types are: ide, scsi, sd, mtd, floppy, 1217 pflash, virtio, none. 1218 1219 ``bus=bus,unit=unit`` 1220 These options define where is connected the drive by defining 1221 the bus number and the unit id. 1222 1223 ``index=index`` 1224 This option defines where is connected the drive by using an 1225 index in the list of available connectors of a given interface 1226 type. 1227 1228 ``media=media`` 1229 This option defines the type of the media: disk or cdrom. 1230 1231 ``snapshot=snapshot`` 1232 snapshot is "on" or "off" and controls snapshot mode for the 1233 given drive (see ``-snapshot``). 1234 1235 ``cache=cache`` 1236 cache is "none", "writeback", "unsafe", "directsync" or 1237 "writethrough" and controls how the host cache is used to access 1238 block data. This is a shortcut that sets the ``cache.direct`` 1239 and ``cache.no-flush`` options (as in ``-blockdev``), and 1240 additionally ``cache.writeback``, which provides a default for 1241 the ``write-cache`` option of block guest devices (as in 1242 ``-device``). The modes correspond to the following settings: 1243 1244 ============= =============== ============ ============== 1245 \ cache.writeback cache.direct cache.no-flush 1246 ============= =============== ============ ============== 1247 writeback on off off 1248 none on on off 1249 writethrough off off off 1250 directsync off on off 1251 unsafe on off on 1252 ============= =============== ============ ============== 1253 1254 The default mode is ``cache=writeback``. 1255 1256 ``aio=aio`` 1257 aio is "threads", "native", or "io_uring" and selects between pthread 1258 based disk I/O, native Linux AIO, or Linux io_uring API. 1259 1260 ``format=format`` 1261 Specify which disk format will be used rather than detecting the 1262 format. Can be used to specify format=raw to avoid interpreting 1263 an untrusted format header. 1264 1265 ``werror=action,rerror=action`` 1266 Specify which action to take on write and read errors. Valid 1267 actions are: "ignore" (ignore the error and try to continue), 1268 "stop" (pause QEMU), "report" (report the error to the guest), 1269 "enospc" (pause QEMU only if the host disk is full; report the 1270 error to the guest otherwise). The default setting is 1271 ``werror=enospc`` and ``rerror=report``. 1272 1273 ``copy-on-read=copy-on-read`` 1274 copy-on-read is "on" or "off" and enables whether to copy read 1275 backing file sectors into the image file. 1276 1277 ``bps=b,bps_rd=r,bps_wr=w`` 1278 Specify bandwidth throttling limits in bytes per second, either 1279 for all request types or for reads or writes only. Small values 1280 can lead to timeouts or hangs inside the guest. A safe minimum 1281 for disks is 2 MB/s. 1282 1283 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1284 Specify bursts in bytes per second, either for all request types 1285 or for reads or writes only. Bursts allow the guest I/O to spike 1286 above the limit temporarily. 1287 1288 ``iops=i,iops_rd=r,iops_wr=w`` 1289 Specify request rate limits in requests per second, either for 1290 all request types or for reads or writes only. 1291 1292 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1293 Specify bursts in requests per second, either for all request 1294 types or for reads or writes only. Bursts allow the guest I/O to 1295 spike above the limit temporarily. 1296 1297 ``iops_size=is`` 1298 Let every is bytes of a request count as a new request for iops 1299 throttling purposes. Use this option to prevent guests from 1300 circumventing iops limits by sending fewer but larger requests. 1301 1302 ``group=g`` 1303 Join a throttling quota group with given name g. All drives that 1304 are members of the same group are accounted for together. Use 1305 this option to prevent guests from circumventing throttling 1306 limits by using many small disks instead of a single larger 1307 disk. 1308 1309 By default, the ``cache.writeback=on`` mode is used. It will report 1310 data writes as completed as soon as the data is present in the host 1311 page cache. This is safe as long as your guest OS makes sure to 1312 correctly flush disk caches where needed. If your guest OS does not 1313 handle volatile disk write caches correctly and your host crashes or 1314 loses power, then the guest may experience data corruption. 1315 1316 For such guests, you should consider using ``cache.writeback=off``. 1317 This means that the host page cache will be used to read and write 1318 data, but write notification will be sent to the guest only after 1319 QEMU has made sure to flush each write to the disk. Be aware that 1320 this has a major impact on performance. 1321 1322 When using the ``-snapshot`` option, unsafe caching is always used. 1323 1324 Copy-on-read avoids accessing the same backing file sectors 1325 repeatedly and is useful when the backing file is over a slow 1326 network. By default copy-on-read is off. 1327 1328 Instead of ``-cdrom`` you can use: 1329 1330 .. parsed-literal:: 1331 1332 |qemu_system| -drive file=file,index=2,media=cdrom 1333 1334 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1335 1336 .. parsed-literal:: 1337 1338 |qemu_system| -drive file=file,index=0,media=disk 1339 |qemu_system| -drive file=file,index=1,media=disk 1340 |qemu_system| -drive file=file,index=2,media=disk 1341 |qemu_system| -drive file=file,index=3,media=disk 1342 1343 You can open an image using pre-opened file descriptors from an fd 1344 set: 1345 1346 .. parsed-literal:: 1347 1348 |qemu_system| \\ 1349 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1350 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1351 -drive file=/dev/fdset/2,index=0,media=disk 1352 1353 You can connect a CDROM to the slave of ide0: 1354 1355 .. parsed-literal:: 1356 1357 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1358 1359 If you don't specify the "file=" argument, you define an empty 1360 drive: 1361 1362 .. parsed-literal:: 1363 1364 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1365 1366 Instead of ``-fda``, ``-fdb``, you can use: 1367 1368 .. parsed-literal:: 1369 1370 |qemu_system_x86| -drive file=file,index=0,if=floppy 1371 |qemu_system_x86| -drive file=file,index=1,if=floppy 1372 1373 By default, interface is "ide" and index is automatically 1374 incremented: 1375 1376 .. parsed-literal:: 1377 1378 |qemu_system_x86| -drive file=a -drive file=b" 1379 1380 is interpreted like: 1381 1382 .. parsed-literal:: 1383 1384 |qemu_system_x86| -hda a -hdb b 1385ERST 1386 1387DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1388 "-mtdblock file use 'file' as on-board Flash memory image\n", 1389 QEMU_ARCH_ALL) 1390SRST 1391``-mtdblock file`` 1392 Use file as on-board Flash memory image. 1393ERST 1394 1395DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1396 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1397SRST 1398``-sd file`` 1399 Use file as SecureDigital card image. 1400ERST 1401 1402DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1403 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1404SRST 1405``-pflash file`` 1406 Use file as a parallel flash image. 1407ERST 1408 1409DEF("snapshot", 0, QEMU_OPTION_snapshot, 1410 "-snapshot write to temporary files instead of disk image files\n", 1411 QEMU_ARCH_ALL) 1412SRST 1413``-snapshot`` 1414 Write to temporary files instead of disk image files. In this case, 1415 the raw disk image you use is not written back. You can however 1416 force the write back by pressing C-a s (see the :ref:`disk images` 1417 chapter in the System Emulation Users Guide). 1418ERST 1419 1420DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1421 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1422 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1423 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1424 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1425 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1426 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1427 " [[,throttling.iops-size=is]]\n" 1428 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1429 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1430 "-fsdev synth,id=id\n", 1431 QEMU_ARCH_ALL) 1432 1433SRST 1434``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1435 \ 1436``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1437 \ 1438``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1439 \ 1440``-fsdev synth,id=id[,readonly=on]`` 1441 Define a new file system device. Valid options are: 1442 1443 ``local`` 1444 Accesses to the filesystem are done by QEMU. 1445 1446 ``proxy`` 1447 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1448 1449 ``synth`` 1450 Synthetic filesystem, only used by QTests. 1451 1452 ``id=id`` 1453 Specifies identifier for this device. 1454 1455 ``path=path`` 1456 Specifies the export path for the file system device. Files 1457 under this path will be available to the 9p client on the guest. 1458 1459 ``security_model=security_model`` 1460 Specifies the security model to be used for this export path. 1461 Supported security models are "passthrough", "mapped-xattr", 1462 "mapped-file" and "none". In "passthrough" security model, files 1463 are stored using the same credentials as they are created on the 1464 guest. This requires QEMU to run as root. In "mapped-xattr" 1465 security model, some of the file attributes like uid, gid, mode 1466 bits and link target are stored as file attributes. For 1467 "mapped-file" these attributes are stored in the hidden 1468 .virtfs\_metadata directory. Directories exported by this 1469 security model cannot interact with other unix tools. "none" 1470 security model is same as passthrough except the sever won't 1471 report failures if it fails to set file attributes like 1472 ownership. Security model is mandatory only for local fsdriver. 1473 Other fsdrivers (like proxy) don't take security model as a 1474 parameter. 1475 1476 ``writeout=writeout`` 1477 This is an optional argument. The only supported value is 1478 "immediate". This means that host page cache will be used to 1479 read and write data but write notification will be sent to the 1480 guest only when the data has been reported as written by the 1481 storage subsystem. 1482 1483 ``readonly=on`` 1484 Enables exporting 9p share as a readonly mount for guests. By 1485 default read-write access is given. 1486 1487 ``socket=socket`` 1488 Enables proxy filesystem driver to use passed socket file for 1489 communicating with virtfs-proxy-helper(1). 1490 1491 ``sock_fd=sock_fd`` 1492 Enables proxy filesystem driver to use passed socket descriptor 1493 for communicating with virtfs-proxy-helper(1). Usually a helper 1494 like libvirt will create socketpair and pass one of the fds as 1495 sock\_fd. 1496 1497 ``fmode=fmode`` 1498 Specifies the default mode for newly created files on the host. 1499 Works only with security models "mapped-xattr" and 1500 "mapped-file". 1501 1502 ``dmode=dmode`` 1503 Specifies the default mode for newly created directories on the 1504 host. Works only with security models "mapped-xattr" and 1505 "mapped-file". 1506 1507 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1508 Specify bandwidth throttling limits in bytes per second, either 1509 for all request types or for reads or writes only. 1510 1511 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1512 Specify bursts in bytes per second, either for all request types 1513 or for reads or writes only. Bursts allow the guest I/O to spike 1514 above the limit temporarily. 1515 1516 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1517 Specify request rate limits in requests per second, either for 1518 all request types or for reads or writes only. 1519 1520 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1521 Specify bursts in requests per second, either for all request 1522 types or for reads or writes only. Bursts allow the guest I/O to 1523 spike above the limit temporarily. 1524 1525 ``throttling.iops-size=is`` 1526 Let every is bytes of a request count as a new request for iops 1527 throttling purposes. 1528 1529 -fsdev option is used along with -device driver "virtio-9p-...". 1530 1531``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1532 Options for virtio-9p-... driver are: 1533 1534 ``type`` 1535 Specifies the variant to be used. Supported values are "pci", 1536 "ccw" or "device", depending on the machine type. 1537 1538 ``fsdev=id`` 1539 Specifies the id value specified along with -fsdev option. 1540 1541 ``mount_tag=mount_tag`` 1542 Specifies the tag name to be used by the guest to mount this 1543 export point. 1544ERST 1545 1546DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1547 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1548 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1549 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1550 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1551 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1552 QEMU_ARCH_ALL) 1553 1554SRST 1555``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1556 \ 1557``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1558 \ 1559``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1560 \ 1561``-virtfs synth,mount_tag=mount_tag`` 1562 Define a new virtual filesystem device and expose it to the guest using 1563 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1564 directory on host is made directly accessible by guest as a pass-through 1565 file system by using the 9P network protocol for communication between 1566 host and guests, if desired even accessible, shared by several guests 1567 simultaniously. 1568 1569 Note that ``-virtfs`` is actually just a convenience shortcut for its 1570 generalized form ``-fsdev -device virtio-9p-pci``. 1571 1572 The general form of pass-through file system options are: 1573 1574 ``local`` 1575 Accesses to the filesystem are done by QEMU. 1576 1577 ``proxy`` 1578 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1579 1580 ``synth`` 1581 Synthetic filesystem, only used by QTests. 1582 1583 ``id=id`` 1584 Specifies identifier for the filesystem device 1585 1586 ``path=path`` 1587 Specifies the export path for the file system device. Files 1588 under this path will be available to the 9p client on the guest. 1589 1590 ``security_model=security_model`` 1591 Specifies the security model to be used for this export path. 1592 Supported security models are "passthrough", "mapped-xattr", 1593 "mapped-file" and "none". In "passthrough" security model, files 1594 are stored using the same credentials as they are created on the 1595 guest. This requires QEMU to run as root. In "mapped-xattr" 1596 security model, some of the file attributes like uid, gid, mode 1597 bits and link target are stored as file attributes. For 1598 "mapped-file" these attributes are stored in the hidden 1599 .virtfs\_metadata directory. Directories exported by this 1600 security model cannot interact with other unix tools. "none" 1601 security model is same as passthrough except the sever won't 1602 report failures if it fails to set file attributes like 1603 ownership. Security model is mandatory only for local fsdriver. 1604 Other fsdrivers (like proxy) don't take security model as a 1605 parameter. 1606 1607 ``writeout=writeout`` 1608 This is an optional argument. The only supported value is 1609 "immediate". This means that host page cache will be used to 1610 read and write data but write notification will be sent to the 1611 guest only when the data has been reported as written by the 1612 storage subsystem. 1613 1614 ``readonly=on`` 1615 Enables exporting 9p share as a readonly mount for guests. By 1616 default read-write access is given. 1617 1618 ``socket=socket`` 1619 Enables proxy filesystem driver to use passed socket file for 1620 communicating with virtfs-proxy-helper(1). Usually a helper like 1621 libvirt will create socketpair and pass one of the fds as 1622 sock\_fd. 1623 1624 ``sock_fd`` 1625 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1626 socket descriptor for interfacing with virtfs-proxy-helper(1). 1627 1628 ``fmode=fmode`` 1629 Specifies the default mode for newly created files on the host. 1630 Works only with security models "mapped-xattr" and 1631 "mapped-file". 1632 1633 ``dmode=dmode`` 1634 Specifies the default mode for newly created directories on the 1635 host. Works only with security models "mapped-xattr" and 1636 "mapped-file". 1637 1638 ``mount_tag=mount_tag`` 1639 Specifies the tag name to be used by the guest to mount this 1640 export point. 1641 1642 ``multidevs=multidevs`` 1643 Specifies how to deal with multiple devices being shared with a 1644 9p export. Supported behaviours are either "remap", "forbid" or 1645 "warn". The latter is the default behaviour on which virtfs 9p 1646 expects only one device to be shared with the same export, and 1647 if more than one device is shared and accessed via the same 9p 1648 export then only a warning message is logged (once) by qemu on 1649 host side. In order to avoid file ID collisions on guest you 1650 should either create a separate virtfs export for each device to 1651 be shared with guests (recommended way) or you might use "remap" 1652 instead which allows you to share multiple devices with only one 1653 export instead, which is achieved by remapping the original 1654 inode numbers from host to guest in a way that would prevent 1655 such collisions. Remapping inodes in such use cases is required 1656 because the original device IDs from host are never passed and 1657 exposed on guest. Instead all files of an export shared with 1658 virtfs always share the same device id on guest. So two files 1659 with identical inode numbers but from actually different devices 1660 on host would otherwise cause a file ID collision and hence 1661 potential misbehaviours on guest. "forbid" on the other hand 1662 assumes like "warn" that only one device is shared by the same 1663 export, however it will not only log a warning message but also 1664 deny access to additional devices on guest. Note though that 1665 "forbid" does currently not block all possible file access 1666 operations (e.g. readdir() would still return entries from other 1667 devices). 1668ERST 1669 1670DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1671 "-iscsi [user=user][,password=password]\n" 1672 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1673 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1674 " [,timeout=timeout]\n" 1675 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1676 1677SRST 1678``-iscsi`` 1679 Configure iSCSI session parameters. 1680ERST 1681 1682DEFHEADING() 1683 1684DEFHEADING(USB options:) 1685 1686DEF("usb", 0, QEMU_OPTION_usb, 1687 "-usb enable on-board USB host controller (if not enabled by default)\n", 1688 QEMU_ARCH_ALL) 1689SRST 1690``-usb`` 1691 Enable USB emulation on machine types with an on-board USB host 1692 controller (if not enabled by default). Note that on-board USB host 1693 controllers may not support USB 3.0. In this case 1694 ``-device qemu-xhci`` can be used instead on machines with PCI. 1695ERST 1696 1697DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1698 "-usbdevice name add the host or guest USB device 'name'\n", 1699 QEMU_ARCH_ALL) 1700SRST 1701``-usbdevice devname`` 1702 Add the USB device devname. Note that this option is deprecated, 1703 please use ``-device usb-...`` instead. See the chapter about 1704 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1705 1706 ``mouse`` 1707 Virtual Mouse. This will override the PS/2 mouse emulation when 1708 activated. 1709 1710 ``tablet`` 1711 Pointer device that uses absolute coordinates (like a 1712 touchscreen). This means QEMU is able to report the mouse 1713 position without having to grab the mouse. Also overrides the 1714 PS/2 mouse emulation when activated. 1715 1716 ``braille`` 1717 Braille device. This will use BrlAPI to display the braille 1718 output on a real or fake device. 1719ERST 1720 1721DEFHEADING() 1722 1723DEFHEADING(Display options:) 1724 1725DEF("display", HAS_ARG, QEMU_OPTION_display, 1726#if defined(CONFIG_SPICE) 1727 "-display spice-app[,gl=on|off]\n" 1728#endif 1729#if defined(CONFIG_SDL) 1730 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1731 " [,window_close=on|off][,gl=on|core|es|off]\n" 1732#endif 1733#if defined(CONFIG_GTK) 1734 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1735#endif 1736#if defined(CONFIG_VNC) 1737 "-display vnc=<display>[,<optargs>]\n" 1738#endif 1739#if defined(CONFIG_CURSES) 1740 "-display curses[,charset=<encoding>]\n" 1741#endif 1742#if defined(CONFIG_OPENGL) 1743 "-display egl-headless[,rendernode=<file>]\n" 1744#endif 1745 "-display none\n" 1746 " select display backend type\n" 1747 " The default display is equivalent to\n " 1748#if defined(CONFIG_GTK) 1749 "\"-display gtk\"\n" 1750#elif defined(CONFIG_SDL) 1751 "\"-display sdl\"\n" 1752#elif defined(CONFIG_COCOA) 1753 "\"-display cocoa\"\n" 1754#elif defined(CONFIG_VNC) 1755 "\"-vnc localhost:0,to=99,id=default\"\n" 1756#else 1757 "\"-display none\"\n" 1758#endif 1759 , QEMU_ARCH_ALL) 1760SRST 1761``-display type`` 1762 Select type of display to use. This option is a replacement for the 1763 old style -sdl/-curses/... options. Use ``-display help`` to list 1764 the available display types. Valid values for type are 1765 1766 ``sdl`` 1767 Display video output via SDL (usually in a separate graphics 1768 window; see the SDL documentation for other possibilities). 1769 1770 ``curses`` 1771 Display video output via curses. For graphics device models 1772 which support a text mode, QEMU can display this output using a 1773 curses/ncurses interface. Nothing is displayed when the graphics 1774 device is in graphical mode or if the graphics device does not 1775 support a text mode. Generally only the VGA device models 1776 support text mode. The font charset used by the guest can be 1777 specified with the ``charset`` option, for example 1778 ``charset=CP850`` for IBM CP850 encoding. The default is 1779 ``CP437``. 1780 1781 ``none`` 1782 Do not display video output. The guest will still see an 1783 emulated graphics card, but its output will not be displayed to 1784 the QEMU user. This option differs from the -nographic option in 1785 that it only affects what is done with video output; -nographic 1786 also changes the destination of the serial and parallel port 1787 data. 1788 1789 ``gtk`` 1790 Display video output in a GTK window. This interface provides 1791 drop-down menus and other UI elements to configure and control 1792 the VM during runtime. 1793 1794 ``vnc`` 1795 Start a VNC server on display <arg> 1796 1797 ``egl-headless`` 1798 Offload all OpenGL operations to a local DRI device. For any 1799 graphical display, this display needs to be paired with either 1800 VNC or SPICE displays. 1801 1802 ``spice-app`` 1803 Start QEMU as a Spice server and launch the default Spice client 1804 application. The Spice server will redirect the serial consoles 1805 and QEMU monitors. (Since 4.0) 1806ERST 1807 1808DEF("nographic", 0, QEMU_OPTION_nographic, 1809 "-nographic disable graphical output and redirect serial I/Os to console\n", 1810 QEMU_ARCH_ALL) 1811SRST 1812``-nographic`` 1813 Normally, if QEMU is compiled with graphical window support, it 1814 displays output such as guest graphics, guest console, and the QEMU 1815 monitor in a window. With this option, you can totally disable 1816 graphical output so that QEMU is a simple command line application. 1817 The emulated serial port is redirected on the console and muxed with 1818 the monitor (unless redirected elsewhere explicitly). Therefore, you 1819 can still use QEMU to debug a Linux kernel with a serial console. 1820 Use C-a h for help on switching between the console and monitor. 1821ERST 1822 1823DEF("curses", 0, QEMU_OPTION_curses, 1824 "-curses shorthand for -display curses\n", 1825 QEMU_ARCH_ALL) 1826SRST 1827``-curses`` 1828 Normally, if QEMU is compiled with graphical window support, it 1829 displays output such as guest graphics, guest console, and the QEMU 1830 monitor in a window. With this option, QEMU can display the VGA 1831 output when in text mode using a curses/ncurses interface. Nothing 1832 is displayed in graphical mode. 1833ERST 1834 1835DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1836 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1837 QEMU_ARCH_ALL) 1838SRST 1839``-alt-grab`` 1840 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1841 this also affects the special keys (for fullscreen, monitor-mode 1842 switching, etc). 1843ERST 1844 1845DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1846 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1847 QEMU_ARCH_ALL) 1848SRST 1849``-ctrl-grab`` 1850 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1851 also affects the special keys (for fullscreen, monitor-mode 1852 switching, etc). 1853ERST 1854 1855DEF("no-quit", 0, QEMU_OPTION_no_quit, 1856 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1857SRST 1858``-no-quit`` 1859 Disable SDL window close capability. 1860ERST 1861 1862DEF("sdl", 0, QEMU_OPTION_sdl, 1863 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1864SRST 1865``-sdl`` 1866 Enable SDL. 1867ERST 1868 1869DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1870 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1871 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1872 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1873 " [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n" 1874 " [,tls-ciphers=<list>]\n" 1875 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1876 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1877 " [,sasl][,password=<secret>][,disable-ticketing]\n" 1878 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1879 " [,jpeg-wan-compression=[auto|never|always]]\n" 1880 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1881 " [,streaming-video=[off|all|filter]][,disable-copy-paste]\n" 1882 " [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n" 1883 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1884 " [,gl=[on|off]][,rendernode=<file>]\n" 1885 " enable spice\n" 1886 " at least one of {port, tls-port} is mandatory\n", 1887 QEMU_ARCH_ALL) 1888SRST 1889``-spice option[,option[,...]]`` 1890 Enable the spice remote desktop protocol. Valid options are 1891 1892 ``port=<nr>`` 1893 Set the TCP port spice is listening on for plaintext channels. 1894 1895 ``addr=<addr>`` 1896 Set the IP address spice is listening on. Default is any 1897 address. 1898 1899 ``ipv4``; \ ``ipv6``; \ ``unix`` 1900 Force using the specified IP version. 1901 1902 ``password=<secret>`` 1903 Set the password you need to authenticate. 1904 1905 ``sasl`` 1906 Require that the client use SASL to authenticate with the spice. 1907 The exact choice of authentication method used is controlled 1908 from the system / user's SASL configuration file for the 'qemu' 1909 service. This is typically found in /etc/sasl2/qemu.conf. If 1910 running QEMU as an unprivileged user, an environment variable 1911 SASL\_CONF\_PATH can be used to make it search alternate 1912 locations for the service config. While some SASL auth methods 1913 can also provide data encryption (eg GSSAPI), it is recommended 1914 that SASL always be combined with the 'tls' and 'x509' settings 1915 to enable use of SSL and server certificates. This ensures a 1916 data encryption preventing compromise of authentication 1917 credentials. 1918 1919 ``disable-ticketing`` 1920 Allow client connects without authentication. 1921 1922 ``disable-copy-paste`` 1923 Disable copy paste between the client and the guest. 1924 1925 ``disable-agent-file-xfer`` 1926 Disable spice-vdagent based file-xfer between the client and the 1927 guest. 1928 1929 ``tls-port=<nr>`` 1930 Set the TCP port spice is listening on for encrypted channels. 1931 1932 ``x509-dir=<dir>`` 1933 Set the x509 file directory. Expects same filenames as -vnc 1934 $display,x509=$dir 1935 1936 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 1937 The x509 file names can also be configured individually. 1938 1939 ``tls-ciphers=<list>`` 1940 Specify which ciphers to use. 1941 1942 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 1943 Force specific channel to be used with or without TLS 1944 encryption. The options can be specified multiple times to 1945 configure multiple channels. The special name "default" can be 1946 used to set the default mode. For channels which are not 1947 explicitly forced into one mode the spice client is allowed to 1948 pick tls/plaintext as he pleases. 1949 1950 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 1951 Configure image compression (lossless). Default is auto\_glz. 1952 1953 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 1954 Configure wan image compression (lossy for slow links). Default 1955 is auto. 1956 1957 ``streaming-video=[off|all|filter]`` 1958 Configure video stream detection. Default is off. 1959 1960 ``agent-mouse=[on|off]`` 1961 Enable/disable passing mouse events via vdagent. Default is on. 1962 1963 ``playback-compression=[on|off]`` 1964 Enable/disable audio stream compression (using celt 0.5.1). 1965 Default is on. 1966 1967 ``seamless-migration=[on|off]`` 1968 Enable/disable spice seamless migration. Default is off. 1969 1970 ``gl=[on|off]`` 1971 Enable/disable OpenGL context. Default is off. 1972 1973 ``rendernode=<file>`` 1974 DRM render node for OpenGL rendering. If not specified, it will 1975 pick the first available. (Since 2.9) 1976ERST 1977 1978DEF("portrait", 0, QEMU_OPTION_portrait, 1979 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 1980 QEMU_ARCH_ALL) 1981SRST 1982``-portrait`` 1983 Rotate graphical output 90 deg left (only PXA LCD). 1984ERST 1985 1986DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 1987 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 1988 QEMU_ARCH_ALL) 1989SRST 1990``-rotate deg`` 1991 Rotate graphical output some deg left (only PXA LCD). 1992ERST 1993 1994DEF("vga", HAS_ARG, QEMU_OPTION_vga, 1995 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 1996 " select video card type\n", QEMU_ARCH_ALL) 1997SRST 1998``-vga type`` 1999 Select type of VGA card to emulate. Valid values for type are 2000 2001 ``cirrus`` 2002 Cirrus Logic GD5446 Video card. All Windows versions starting 2003 from Windows 95 should recognize and use this graphic card. For 2004 optimal performances, use 16 bit color depth in the guest and 2005 the host OS. (This card was the default before QEMU 2.2) 2006 2007 ``std`` 2008 Standard VGA card with Bochs VBE extensions. If your guest OS 2009 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2010 you want to use high resolution modes (>= 1280x1024x16) then you 2011 should use this option. (This card is the default since QEMU 2012 2.2) 2013 2014 ``vmware`` 2015 VMWare SVGA-II compatible adapter. Use it if you have 2016 sufficiently recent XFree86/XOrg server or Windows guest with a 2017 driver for this card. 2018 2019 ``qxl`` 2020 QXL paravirtual graphic card. It is VGA compatible (including 2021 VESA 2.0 VBE support). Works best with qxl guest drivers 2022 installed though. Recommended choice when using the spice 2023 protocol. 2024 2025 ``tcx`` 2026 (sun4m only) Sun TCX framebuffer. This is the default 2027 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2028 colour depths at a fixed resolution of 1024x768. 2029 2030 ``cg3`` 2031 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2032 framebuffer for sun4m machines available in both 1024x768 2033 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2034 wishing to run older Solaris versions. 2035 2036 ``virtio`` 2037 Virtio VGA card. 2038 2039 ``none`` 2040 Disable VGA card. 2041ERST 2042 2043DEF("full-screen", 0, QEMU_OPTION_full_screen, 2044 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2045SRST 2046``-full-screen`` 2047 Start in full screen. 2048ERST 2049 2050DEF("g", HAS_ARG, QEMU_OPTION_g , 2051 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2052 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2053SRST 2054``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2055 Set the initial graphical resolution and depth (PPC, SPARC only). 2056 2057 For PPC the default is 800x600x32. 2058 2059 For SPARC with the TCX graphics device, the default is 1024x768x8 2060 with the option of 1024x768x24. For cgthree, the default is 2061 1024x768x8 with the option of 1152x900x8 for people who wish to use 2062 OBP. 2063ERST 2064 2065DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2066 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2067SRST 2068``-vnc display[,option[,option[,...]]]`` 2069 Normally, if QEMU is compiled with graphical window support, it 2070 displays output such as guest graphics, guest console, and the QEMU 2071 monitor in a window. With this option, you can have QEMU listen on 2072 VNC display display and redirect the VGA display over the VNC 2073 session. It is very useful to enable the usb tablet device when 2074 using this option (option ``-device usb-tablet``). When using the 2075 VNC display, you must use the ``-k`` parameter to set the keyboard 2076 layout if you are not using en-us. Valid syntax for the display is 2077 2078 ``to=L`` 2079 With this option, QEMU will try next available VNC displays, 2080 until the number L, if the origianlly defined "-vnc display" is 2081 not available, e.g. port 5900+display is already used by another 2082 application. By default, to=0. 2083 2084 ``host:d`` 2085 TCP connections will only be allowed from host on display d. By 2086 convention the TCP port is 5900+d. Optionally, host can be 2087 omitted in which case the server will accept connections from 2088 any host. 2089 2090 ``unix:path`` 2091 Connections will be allowed over UNIX domain sockets where path 2092 is the location of a unix socket to listen for connections on. 2093 2094 ``none`` 2095 VNC is initialized but not started. The monitor ``change`` 2096 command can be used to later start the VNC server. 2097 2098 Following the display value there may be one or more option flags 2099 separated by commas. Valid options are 2100 2101 ``reverse`` 2102 Connect to a listening VNC client via a "reverse" connection. 2103 The client is specified by the display. For reverse network 2104 connections (host:d,``reverse``), the d argument is a TCP port 2105 number, not a display number. 2106 2107 ``websocket`` 2108 Opens an additional TCP listening port dedicated to VNC 2109 Websocket connections. If a bare websocket option is given, the 2110 Websocket port is 5700+display. An alternative port can be 2111 specified with the syntax ``websocket``\ =port. 2112 2113 If host is specified connections will only be allowed from this 2114 host. It is possible to control the websocket listen address 2115 independently, using the syntax ``websocket``\ =host:port. 2116 2117 If no TLS credentials are provided, the websocket connection 2118 runs in unencrypted mode. If TLS credentials are provided, the 2119 websocket connection requires encrypted client connections. 2120 2121 ``password`` 2122 Require that password based authentication is used for client 2123 connections. 2124 2125 The password must be set separately using the ``set_password`` 2126 command in the :ref:`QEMU monitor`. The 2127 syntax to change your password is: 2128 ``set_password <protocol> <password>`` where <protocol> could be 2129 either "vnc" or "spice". 2130 2131 If you would like to change <protocol> password expiration, you 2132 should use ``expire_password <protocol> <expiration-time>`` 2133 where expiration time could be one of the following options: 2134 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2135 make password expire in 60 seconds, or 1335196800 to make 2136 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2137 this date and time). 2138 2139 You can also use keywords "now" or "never" for the expiration 2140 time to allow <protocol> password to expire immediately or never 2141 expire. 2142 2143 ``tls-creds=ID`` 2144 Provides the ID of a set of TLS credentials to use to secure the 2145 VNC server. They will apply to both the normal VNC server socket 2146 and the websocket socket (if enabled). Setting TLS credentials 2147 will cause the VNC server socket to enable the VeNCrypt auth 2148 mechanism. The credentials should have been previously created 2149 using the ``-object tls-creds`` argument. 2150 2151 ``tls-authz=ID`` 2152 Provides the ID of the QAuthZ authorization object against which 2153 the client's x509 distinguished name will validated. This object 2154 is only resolved at time of use, so can be deleted and recreated 2155 on the fly while the VNC server is active. If missing, it will 2156 default to denying access. 2157 2158 ``sasl`` 2159 Require that the client use SASL to authenticate with the VNC 2160 server. The exact choice of authentication method used is 2161 controlled from the system / user's SASL configuration file for 2162 the 'qemu' service. This is typically found in 2163 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2164 an environment variable SASL\_CONF\_PATH can be used to make it 2165 search alternate locations for the service config. While some 2166 SASL auth methods can also provide data encryption (eg GSSAPI), 2167 it is recommended that SASL always be combined with the 'tls' 2168 and 'x509' settings to enable use of SSL and server 2169 certificates. This ensures a data encryption preventing 2170 compromise of authentication credentials. See the 2171 :ref:`VNC security` section in the System Emulation Users Guide 2172 for details on using SASL authentication. 2173 2174 ``sasl-authz=ID`` 2175 Provides the ID of the QAuthZ authorization object against which 2176 the client's SASL username will validated. This object is only 2177 resolved at time of use, so can be deleted and recreated on the 2178 fly while the VNC server is active. If missing, it will default 2179 to denying access. 2180 2181 ``acl`` 2182 Legacy method for enabling authorization of clients against the 2183 x509 distinguished name and SASL username. It results in the 2184 creation of two ``authz-list`` objects with IDs of 2185 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2186 objects must be configured with the HMP ACL commands. 2187 2188 This option is deprecated and should no longer be used. The new 2189 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2190 2191 ``lossy`` 2192 Enable lossy compression methods (gradient, JPEG, ...). If this 2193 option is set, VNC client may receive lossy framebuffer updates 2194 depending on its encoding settings. Enabling this option can 2195 save a lot of bandwidth at the expense of quality. 2196 2197 ``non-adaptive`` 2198 Disable adaptive encodings. Adaptive encodings are enabled by 2199 default. An adaptive encoding will try to detect frequently 2200 updated screen regions, and send updates in these regions using 2201 a lossy encoding (like JPEG). This can be really helpful to save 2202 bandwidth when playing videos. Disabling adaptive encodings 2203 restores the original static behavior of encodings like Tight. 2204 2205 ``share=[allow-exclusive|force-shared|ignore]`` 2206 Set display sharing policy. 'allow-exclusive' allows clients to 2207 ask for exclusive access. As suggested by the rfb spec this is 2208 implemented by dropping other connections. Connecting multiple 2209 clients in parallel requires all clients asking for a shared 2210 session (vncviewer: -shared switch). This is the default. 2211 'force-shared' disables exclusive client access. Useful for 2212 shared desktop sessions, where you don't want someone forgetting 2213 specify -shared disconnect everybody else. 'ignore' completely 2214 ignores the shared flag and allows everybody connect 2215 unconditionally. Doesn't conform to the rfb spec but is 2216 traditional QEMU behavior. 2217 2218 ``key-delay-ms`` 2219 Set keyboard delay, for key down and key up events, in 2220 milliseconds. Default is 10. Keyboards are low-bandwidth 2221 devices, so this slowdown can help the device and guest to keep 2222 up and not lose events in case events are arriving in bulk. 2223 Possible causes for the latter are flaky network connections, or 2224 scripts for automated testing. 2225 2226 ``audiodev=audiodev`` 2227 Use the specified audiodev when the VNC client requests audio 2228 transmission. When not using an -audiodev argument, this option 2229 must be omitted, otherwise is must be present and specify a 2230 valid audiodev. 2231 2232 ``power-control`` 2233 Permit the remote client to issue shutdown, reboot or reset power 2234 control requests. 2235ERST 2236 2237ARCHHEADING(, QEMU_ARCH_I386) 2238 2239ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2240 2241DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2242 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2243 QEMU_ARCH_I386) 2244SRST 2245``-win2k-hack`` 2246 Use it when installing Windows 2000 to avoid a disk full bug. After 2247 Windows 2000 is installed, you no longer need this option (this 2248 option slows down the IDE transfers). 2249ERST 2250 2251DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2252 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2253 QEMU_ARCH_I386) 2254SRST 2255``-no-fd-bootchk`` 2256 Disable boot signature checking for floppy disks in BIOS. May be 2257 needed to boot from old floppy disks. 2258ERST 2259 2260DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2261 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2262SRST 2263``-no-acpi`` 2264 Disable ACPI (Advanced Configuration and Power Interface) support. 2265 Use it if your guest OS complains about ACPI problems (PC target 2266 machine only). 2267ERST 2268 2269DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2270 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2271SRST 2272``-no-hpet`` 2273 Disable HPET support. 2274ERST 2275 2276DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2277 "-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" 2278 " ACPI table description\n", QEMU_ARCH_I386) 2279SRST 2280``-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]...]`` 2281 Add ACPI table with specified header fields and context from 2282 specified files. For file=, take whole ACPI table from the specified 2283 files, including all ACPI headers (possible overridden by other 2284 options). For data=, only data portion of the table is used, all 2285 header information is specified in the command line. If a SLIC table 2286 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2287 fields will override the same in the RSDT and the FADT (a.k.a. 2288 FACP), in order to ensure the field matches required by the 2289 Microsoft SLIC spec and the ACPI spec. 2290ERST 2291 2292DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2293 "-smbios file=binary\n" 2294 " load SMBIOS entry from binary file\n" 2295 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2296 " [,uefi=on|off]\n" 2297 " specify SMBIOS type 0 fields\n" 2298 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2299 " [,uuid=uuid][,sku=str][,family=str]\n" 2300 " specify SMBIOS type 1 fields\n" 2301 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2302 " [,asset=str][,location=str]\n" 2303 " specify SMBIOS type 2 fields\n" 2304 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2305 " [,sku=str]\n" 2306 " specify SMBIOS type 3 fields\n" 2307 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2308 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2309 " specify SMBIOS type 4 fields\n" 2310 "-smbios type=11[,value=str][,path=filename]\n" 2311 " specify SMBIOS type 11 fields\n" 2312 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2313 " [,asset=str][,part=str][,speed=%d]\n" 2314 " specify SMBIOS type 17 fields\n", 2315 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2316SRST 2317``-smbios file=binary`` 2318 Load SMBIOS entry from binary file. 2319 2320``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2321 Specify SMBIOS type 0 fields 2322 2323``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2324 Specify SMBIOS type 1 fields 2325 2326``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2327 Specify SMBIOS type 2 fields 2328 2329``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2330 Specify SMBIOS type 3 fields 2331 2332``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2333 Specify SMBIOS type 4 fields 2334 2335``-smbios type=11[,value=str][,path=filename]`` 2336 Specify SMBIOS type 11 fields 2337 2338 This argument can be repeated multiple times, and values are added in the order they are parsed. 2339 Applications intending to use OEM strings data are encouraged to use their application name as 2340 a prefix for the value string. This facilitates passing information for multiple applications 2341 concurrently. 2342 2343 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2344 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2345 2346 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2347 the SMBIOS table in the order in which they appear. 2348 2349 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2350 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2351 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2352 data set, for example, by specifying the serial ID of a block device. 2353 2354 An example passing three strings is 2355 2356 .. parsed-literal:: 2357 2358 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2359 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2360 path=/some/file/with/oemstringsdata.txt 2361 2362 In the guest OS this is visible with the ``dmidecode`` command 2363 2364 .. parsed-literal:: 2365 2366 $ dmidecode -t 11 2367 Handle 0x0E00, DMI type 11, 5 bytes 2368 OEM Strings 2369 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2370 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2371 String 3: myapp:some extra data 2372 2373 2374``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2375 Specify SMBIOS type 17 fields 2376ERST 2377 2378DEFHEADING() 2379 2380DEFHEADING(Network options:) 2381 2382DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2383#ifdef CONFIG_SLIRP 2384 "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n" 2385 " [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2386 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2387 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2388 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2389#ifndef _WIN32 2390 "[,smb=dir[,smbserver=addr]]\n" 2391#endif 2392 " configure a user mode network backend with ID 'str',\n" 2393 " its DHCP server and optional services\n" 2394#endif 2395#ifdef _WIN32 2396 "-netdev tap,id=str,ifname=name\n" 2397 " configure a host TAP network backend with ID 'str'\n" 2398#else 2399 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2400 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2401 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2402 " [,poll-us=n]\n" 2403 " configure a host TAP network backend with ID 'str'\n" 2404 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2405 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2406 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2407 " to deconfigure it\n" 2408 " use '[down]script=no' to disable script execution\n" 2409 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2410 " configure it\n" 2411 " use 'fd=h' to connect to an already opened TAP interface\n" 2412 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2413 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2414 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2415 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2416 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2417 " use vhost=on to enable experimental in kernel accelerator\n" 2418 " (only has effect for virtio guests which use MSIX)\n" 2419 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2420 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2421 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2422 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2423 " use 'poll-us=n' to speciy the maximum number of microseconds that could be\n" 2424 " spent on busy polling for vhost net\n" 2425 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2426 " configure a host TAP network backend with ID 'str' that is\n" 2427 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2428 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2429#endif 2430#ifdef __linux__ 2431 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2432 " [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n" 2433 " [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n" 2434 " [,rxcookie=rxcookie][,offset=offset]\n" 2435 " configure a network backend with ID 'str' connected to\n" 2436 " an Ethernet over L2TPv3 pseudowire.\n" 2437 " Linux kernel 3.3+ as well as most routers can talk\n" 2438 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2439 " VM to a router and even VM to Host. It is a nearly-universal\n" 2440 " standard (RFC3931). Note - this implementation uses static\n" 2441 " pre-configured tunnels (same as the Linux kernel).\n" 2442 " use 'src=' to specify source address\n" 2443 " use 'dst=' to specify destination address\n" 2444 " use 'udp=on' to specify udp encapsulation\n" 2445 " use 'srcport=' to specify source udp port\n" 2446 " use 'dstport=' to specify destination udp port\n" 2447 " use 'ipv6=on' to force v6\n" 2448 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2449 " well as a weak security measure\n" 2450 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2451 " use 'txcookie=0x012345678' to specify a txcookie\n" 2452 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2453 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2454 " use 'pincounter=on' to work around broken counter handling in peer\n" 2455 " use 'offset=X' to add an extra offset between header and data\n" 2456#endif 2457 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2458 " configure a network backend to connect to another network\n" 2459 " using a socket connection\n" 2460 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2461 " configure a network backend to connect to a multicast maddr and port\n" 2462 " use 'localaddr=addr' to specify the host address to send packets from\n" 2463 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2464 " configure a network backend to connect to another network\n" 2465 " using an UDP tunnel\n" 2466#ifdef CONFIG_VDE 2467 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2468 " configure a network backend to connect to port 'n' of a vde switch\n" 2469 " running on host and listening for incoming connections on 'socketpath'.\n" 2470 " Use group 'groupname' and mode 'octalmode' to change default\n" 2471 " ownership and permissions for communication port.\n" 2472#endif 2473#ifdef CONFIG_NETMAP 2474 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2475 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2476 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2477 " netmap device, defaults to '/dev/netmap')\n" 2478#endif 2479#ifdef CONFIG_POSIX 2480 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2481 " configure a vhost-user network, backed by a chardev 'dev'\n" 2482#endif 2483#ifdef __linux__ 2484 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2485 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2486#endif 2487 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2488 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2489DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2490 "-nic [tap|bridge|" 2491#ifdef CONFIG_SLIRP 2492 "user|" 2493#endif 2494#ifdef __linux__ 2495 "l2tpv3|" 2496#endif 2497#ifdef CONFIG_VDE 2498 "vde|" 2499#endif 2500#ifdef CONFIG_NETMAP 2501 "netmap|" 2502#endif 2503#ifdef CONFIG_POSIX 2504 "vhost-user|" 2505#endif 2506 "socket][,option][,...][mac=macaddr]\n" 2507 " initialize an on-board / default host NIC (using MAC address\n" 2508 " macaddr) and connect it to the given host network backend\n" 2509 "-nic none use it alone to have zero network devices (the default is to\n" 2510 " provided a 'user' network connection)\n", 2511 QEMU_ARCH_ALL) 2512DEF("net", HAS_ARG, QEMU_OPTION_net, 2513 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2514 " configure or create an on-board (or machine default) NIC and\n" 2515 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2516 "-net [" 2517#ifdef CONFIG_SLIRP 2518 "user|" 2519#endif 2520 "tap|" 2521 "bridge|" 2522#ifdef CONFIG_VDE 2523 "vde|" 2524#endif 2525#ifdef CONFIG_NETMAP 2526 "netmap|" 2527#endif 2528 "socket][,option][,option][,...]\n" 2529 " old way to initialize a host network interface\n" 2530 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2531SRST 2532``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2533 This option is a shortcut for configuring both the on-board 2534 (default) guest NIC hardware and the host network backend in one go. 2535 The host backend options are the same as with the corresponding 2536 ``-netdev`` options below. The guest NIC model can be set with 2537 ``model=modelname``. Use ``model=help`` to list the available device 2538 types. The hardware MAC address can be set with ``mac=macaddr``. 2539 2540 The following two example do exactly the same, to show how ``-nic`` 2541 can be used to shorten the command line length: 2542 2543 .. parsed-literal:: 2544 2545 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2546 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2547 2548``-nic none`` 2549 Indicate that no network devices should be configured. It is used to 2550 override the default configuration (default NIC with "user" host 2551 network backend) which is activated if no other networking options 2552 are provided. 2553 2554``-netdev user,id=id[,option][,option][,...]`` 2555 Configure user mode host network backend which requires no 2556 administrator privilege to run. Valid options are: 2557 2558 ``id=id`` 2559 Assign symbolic name for use in monitor commands. 2560 2561 ``ipv4=on|off and ipv6=on|off`` 2562 Specify that either IPv4 or IPv6 must be enabled. If neither is 2563 specified both protocols are enabled. 2564 2565 ``net=addr[/mask]`` 2566 Set IP network address the guest will see. Optionally specify 2567 the netmask, either in the form a.b.c.d or as number of valid 2568 top-most bits. Default is 10.0.2.0/24. 2569 2570 ``host=addr`` 2571 Specify the guest-visible address of the host. Default is the 2572 2nd IP in the guest network, i.e. x.x.x.2. 2573 2574 ``ipv6-net=addr[/int]`` 2575 Set IPv6 network address the guest will see (default is 2576 fec0::/64). The network prefix is given in the usual hexadecimal 2577 IPv6 address notation. The prefix size is optional, and is given 2578 as the number of valid top-most bits (default is 64). 2579 2580 ``ipv6-host=addr`` 2581 Specify the guest-visible IPv6 address of the host. Default is 2582 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2583 2584 ``restrict=on|off`` 2585 If this option is enabled, the guest will be isolated, i.e. it 2586 will not be able to contact the host and no guest IP packets 2587 will be routed over the host to the outside. This option does 2588 not affect any explicitly set forwarding rules. 2589 2590 ``hostname=name`` 2591 Specifies the client hostname reported by the built-in DHCP 2592 server. 2593 2594 ``dhcpstart=addr`` 2595 Specify the first of the 16 IPs the built-in DHCP server can 2596 assign. Default is the 15th to 31st IP in the guest network, 2597 i.e. x.x.x.15 to x.x.x.31. 2598 2599 ``dns=addr`` 2600 Specify the guest-visible address of the virtual nameserver. The 2601 address must be different from the host address. Default is the 2602 3rd IP in the guest network, i.e. x.x.x.3. 2603 2604 ``ipv6-dns=addr`` 2605 Specify the guest-visible address of the IPv6 virtual 2606 nameserver. The address must be different from the host address. 2607 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2608 2609 ``dnssearch=domain`` 2610 Provides an entry for the domain-search list sent by the 2611 built-in DHCP server. More than one domain suffix can be 2612 transmitted by specifying this option multiple times. If 2613 supported, this will cause the guest to automatically try to 2614 append the given domain suffix(es) in case a domain name can not 2615 be resolved. 2616 2617 Example: 2618 2619 .. parsed-literal:: 2620 2621 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2622 2623 ``domainname=domain`` 2624 Specifies the client domain name reported by the built-in DHCP 2625 server. 2626 2627 ``tftp=dir`` 2628 When using the user mode network stack, activate a built-in TFTP 2629 server. The files in dir will be exposed as the root of a TFTP 2630 server. The TFTP client on the guest must be configured in 2631 binary mode (use the command ``bin`` of the Unix TFTP client). 2632 2633 ``tftp-server-name=name`` 2634 In BOOTP reply, broadcast name as the "TFTP server name" 2635 (RFC2132 option 66). This can be used to advise the guest to 2636 load boot files or configurations from a different server than 2637 the host address. 2638 2639 ``bootfile=file`` 2640 When using the user mode network stack, broadcast file as the 2641 BOOTP filename. In conjunction with ``tftp``, this can be used 2642 to network boot a guest from a local directory. 2643 2644 Example (using pxelinux): 2645 2646 .. parsed-literal:: 2647 2648 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2649 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2650 2651 ``smb=dir[,smbserver=addr]`` 2652 When using the user mode network stack, activate a built-in SMB 2653 server so that Windows OSes can access to the host files in 2654 ``dir`` transparently. The IP address of the SMB server can be 2655 set to addr. By default the 4th IP in the guest network is used, 2656 i.e. x.x.x.4. 2657 2658 In the guest Windows OS, the line: 2659 2660 :: 2661 2662 10.0.2.4 smbserver 2663 2664 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2665 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2666 NT/2000). 2667 2668 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2669 2670 Note that a SAMBA server must be installed on the host OS. 2671 2672 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2673 Redirect incoming TCP or UDP connections to the host port 2674 hostport to the guest IP address guestaddr on guest port 2675 guestport. If guestaddr is not specified, its value is x.x.x.15 2676 (default first address given by the built-in DHCP server). By 2677 specifying hostaddr, the rule can be bound to a specific host 2678 interface. If no connection type is set, TCP is used. This 2679 option can be given multiple times. 2680 2681 For example, to redirect host X11 connection from screen 1 to 2682 guest screen 0, use the following: 2683 2684 .. parsed-literal:: 2685 2686 # on the host 2687 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2688 # this host xterm should open in the guest X11 server 2689 xterm -display :1 2690 2691 To redirect telnet connections from host port 5555 to telnet 2692 port on the guest, use the following: 2693 2694 .. parsed-literal:: 2695 2696 # on the host 2697 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2698 telnet localhost 5555 2699 2700 Then when you use on the host ``telnet localhost 5555``, you 2701 connect to the guest telnet server. 2702 2703 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2704 Forward guest TCP connections to the IP address server on port 2705 port to the character device dev or to a program executed by 2706 cmd:command which gets spawned for each connection. This option 2707 can be given multiple times. 2708 2709 You can either use a chardev directly and have that one used 2710 throughout QEMU's lifetime, like in the following example: 2711 2712 .. parsed-literal:: 2713 2714 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2715 # the guest accesses it 2716 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2717 2718 Or you can execute a command on every TCP connection established 2719 by the guest, so that QEMU behaves similar to an inetd process 2720 for that virtual server: 2721 2722 .. parsed-literal:: 2723 2724 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2725 # and connect the TCP stream to its stdin/stdout 2726 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2727 2728``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2729 Configure a host TAP network backend with ID id. 2730 2731 Use the network script file to configure it and the network script 2732 dfile to deconfigure it. If name is not provided, the OS 2733 automatically provides one. The default network configure script is 2734 ``/etc/qemu-ifup`` and the default network deconfigure script is 2735 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2736 disable script execution. 2737 2738 If running QEMU as an unprivileged user, use the network helper 2739 to configure the TAP interface and attach it to the bridge. 2740 The default network helper executable is 2741 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2742 ``br0``. 2743 2744 ``fd``\ =h can be used to specify the handle of an already opened 2745 host TAP interface. 2746 2747 Examples: 2748 2749 .. parsed-literal:: 2750 2751 #launch a QEMU instance with the default network script 2752 |qemu_system| linux.img -nic tap 2753 2754 .. parsed-literal:: 2755 2756 #launch a QEMU instance with two NICs, each one connected 2757 #to a TAP device 2758 |qemu_system| linux.img \\ 2759 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2760 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2761 2762 .. parsed-literal:: 2763 2764 #launch a QEMU instance with the default network helper to 2765 #connect a TAP device to bridge br0 2766 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2767 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2768 2769``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2770 Connect a host TAP network interface to a host bridge device. 2771 2772 Use the network helper helper to configure the TAP interface and 2773 attach it to the bridge. The default network helper executable is 2774 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2775 ``br0``. 2776 2777 Examples: 2778 2779 .. parsed-literal:: 2780 2781 #launch a QEMU instance with the default network helper to 2782 #connect a TAP device to bridge br0 2783 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2784 2785 .. parsed-literal:: 2786 2787 #launch a QEMU instance with the default network helper to 2788 #connect a TAP device to bridge qemubr0 2789 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2790 2791``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2792 This host network backend can be used to connect the guest's network 2793 to another QEMU virtual machine using a TCP socket connection. If 2794 ``listen`` is specified, QEMU waits for incoming connections on port 2795 (host is optional). ``connect`` is used to connect to another QEMU 2796 instance using the ``listen`` option. ``fd``\ =h specifies an 2797 already opened TCP socket. 2798 2799 Example: 2800 2801 .. parsed-literal:: 2802 2803 # launch a first QEMU instance 2804 |qemu_system| linux.img \\ 2805 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2806 -netdev socket,id=n1,listen=:1234 2807 # connect the network of this instance to the network of the first instance 2808 |qemu_system| linux.img \\ 2809 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2810 -netdev socket,id=n2,connect=127.0.0.1:1234 2811 2812``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2813 Configure a socket host network backend to share the guest's network 2814 traffic with another QEMU virtual machines using a UDP multicast 2815 socket, effectively making a bus for every QEMU with same multicast 2816 address maddr and port. NOTES: 2817 2818 1. Several QEMU can be running on different hosts and share same bus 2819 (assuming correct multicast setup for these hosts). 2820 2821 2. mcast support is compatible with User Mode Linux (argument 2822 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2823 2824 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2825 2826 Example: 2827 2828 .. parsed-literal:: 2829 2830 # launch one QEMU instance 2831 |qemu_system| linux.img \\ 2832 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2833 -netdev socket,id=n1,mcast=230.0.0.1:1234 2834 # launch another QEMU instance on same "bus" 2835 |qemu_system| linux.img \\ 2836 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2837 -netdev socket,id=n2,mcast=230.0.0.1:1234 2838 # launch yet another QEMU instance on same "bus" 2839 |qemu_system| linux.img \\ 2840 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2841 -netdev socket,id=n3,mcast=230.0.0.1:1234 2842 2843 Example (User Mode Linux compat.): 2844 2845 .. parsed-literal:: 2846 2847 # launch QEMU instance (note mcast address selected is UML's default) 2848 |qemu_system| linux.img \\ 2849 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2850 -netdev socket,id=n1,mcast=239.192.168.1:1102 2851 # launch UML 2852 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2853 2854 Example (send packets from host's 1.2.3.4): 2855 2856 .. parsed-literal:: 2857 2858 |qemu_system| linux.img \\ 2859 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2860 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2861 2862``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6][,udp][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 2863 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2864 is a popular protocol to transport Ethernet (and other Layer 2) data 2865 frames between two systems. It is present in routers, firewalls and 2866 the Linux kernel (from version 3.3 onwards). 2867 2868 This transport allows a VM to communicate to another VM, router or 2869 firewall directly. 2870 2871 ``src=srcaddr`` 2872 source address (mandatory) 2873 2874 ``dst=dstaddr`` 2875 destination address (mandatory) 2876 2877 ``udp`` 2878 select udp encapsulation (default is ip). 2879 2880 ``srcport=srcport`` 2881 source udp port. 2882 2883 ``dstport=dstport`` 2884 destination udp port. 2885 2886 ``ipv6`` 2887 force v6, otherwise defaults to v4. 2888 2889 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2890 Cookies are a weak form of security in the l2tpv3 specification. 2891 Their function is mostly to prevent misconfiguration. By default 2892 they are 32 bit. 2893 2894 ``cookie64`` 2895 Set cookie size to 64 bit instead of the default 32 2896 2897 ``counter=off`` 2898 Force a 'cut-down' L2TPv3 with no counter as in 2899 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2900 2901 ``pincounter=on`` 2902 Work around broken counter handling in peer. This may also help 2903 on networks which have packet reorder. 2904 2905 ``offset=offset`` 2906 Add an extra offset between header and data 2907 2908 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 2909 the bridge br-lan on the remote Linux host 1.2.3.4: 2910 2911 .. parsed-literal:: 2912 2913 # Setup tunnel on linux host using raw ip as encapsulation 2914 # on 1.2.3.4 2915 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 2916 encap udp udp_sport 16384 udp_dport 16384 2917 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 2918 0xFFFFFFFF peer_session_id 0xFFFFFFFF 2919 ifconfig vmtunnel0 mtu 1500 2920 ifconfig vmtunnel0 up 2921 brctl addif br-lan vmtunnel0 2922 2923 2924 # on 4.3.2.1 2925 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 2926 2927 |qemu_system| linux.img -device e1000,netdev=n1 \\ 2928 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 2929 2930``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 2931 Configure VDE backend to connect to PORT n of a vde switch running 2932 on host and listening for incoming connections on socketpath. Use 2933 GROUP groupname and MODE octalmode to change default ownership and 2934 permissions for communication port. This option is only available if 2935 QEMU has been compiled with vde support enabled. 2936 2937 Example: 2938 2939 .. parsed-literal:: 2940 2941 # launch vde switch 2942 vde_switch -F -sock /tmp/myswitch 2943 # launch QEMU instance 2944 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 2945 2946``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 2947 Establish a vhost-user netdev, backed by a chardev id. The chardev 2948 should be a unix domain socket backed one. The vhost-user uses a 2949 specifically defined protocol to pass vhost ioctl replacement 2950 messages to an application on the other end of the socket. On 2951 non-MSIX guests, the feature can be forced with vhostforce. Use 2952 'queues=n' to specify the number of queues to be created for 2953 multiqueue vhost-user. 2954 2955 Example: 2956 2957 :: 2958 2959 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 2960 -numa node,memdev=mem \ 2961 -chardev socket,id=chr0,path=/path/to/socket \ 2962 -netdev type=vhost-user,id=net0,chardev=chr0 \ 2963 -device virtio-net-pci,netdev=net0 2964 2965``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 2966 Establish a vhost-vdpa netdev. 2967 2968 vDPA device is a device that uses a datapath which complies with 2969 the virtio specifications with a vendor specific control path. 2970 vDPA devices can be both physically located on the hardware or 2971 emulated by software. 2972 2973``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 2974 Create a hub port on the emulated hub with ID hubid. 2975 2976 The hubport netdev lets you connect a NIC to a QEMU emulated hub 2977 instead of a single netdev. Alternatively, you can also connect the 2978 hubport to another netdev with ID nd by using the ``netdev=nd`` 2979 option. 2980 2981``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 2982 Legacy option to configure or create an on-board (or machine 2983 default) Network Interface Card(NIC) and connect it either to the 2984 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 2985 If model is omitted, then the default NIC model associated with the 2986 machine type is used. Note that the default NIC model may change in 2987 future QEMU releases, so it is highly recommended to always specify 2988 a model. Optionally, the MAC address can be changed to mac, the 2989 device address set to addr (PCI cards only), and a name can be 2990 assigned for use in monitor commands. Optionally, for PCI cards, you 2991 can specify the number v of MSI-X vectors that the card should have; 2992 this option currently only affects virtio cards; set v = 0 to 2993 disable MSI-X. If no ``-net`` option is specified, a single NIC is 2994 created. QEMU can emulate several different models of network card. 2995 Use ``-net nic,model=help`` for a list of available devices for your 2996 target. 2997 2998``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 2999 Configure a host network backend (with the options corresponding to 3000 the same ``-netdev`` option) and connect it to the emulated hub 0 3001 (the default hub). Use name to specify the name of the hub port. 3002ERST 3003 3004DEFHEADING() 3005 3006DEFHEADING(Character device options:) 3007 3008DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3009 "-chardev help\n" 3010 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3011 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n" 3012 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n" 3013 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3014 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n" 3015 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3016 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3017 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n" 3018 " [,logfile=PATH][,logappend=on|off]\n" 3019 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3020 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3021 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3022 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3023 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3024 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3025#ifdef _WIN32 3026 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3027 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3028#else 3029 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3030 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3031#endif 3032#ifdef CONFIG_BRLAPI 3033 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3034#endif 3035#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3036 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3037 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3038 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3039#endif 3040#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3041 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3042 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3043#endif 3044#if defined(CONFIG_SPICE) 3045 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3046 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3047#endif 3048 , QEMU_ARCH_ALL 3049) 3050 3051SRST 3052The general form of a character device option is: 3053 3054``-chardev backend,id=id[,mux=on|off][,options]`` 3055 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3056 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3057 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3058 ``spicevmc``, ``spiceport``. The specific backend will determine the 3059 applicable options. 3060 3061 Use ``-chardev help`` to print all available chardev backend types. 3062 3063 All devices must have an id, which can be any string up to 127 3064 characters long. It is used to uniquely identify this device in 3065 other command line directives. 3066 3067 A character device may be used in multiplexing mode by multiple 3068 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3069 a "1:N" device, and here the "1" end is your specified chardev 3070 backend, and the "N" end is the various parts of QEMU that can talk 3071 to a chardev. If you create a chardev with ``id=myid`` and 3072 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3073 and you can then configure multiple front ends to use that chardev 3074 ID for their input/output. Up to four different front ends can be 3075 connected to a single multiplexed chardev. (Without multiplexing 3076 enabled, a chardev can only be used by a single front end.) For 3077 instance you could use this to allow a single stdio chardev to be 3078 used by two serial ports and the QEMU monitor: 3079 3080 :: 3081 3082 -chardev stdio,mux=on,id=char0 \ 3083 -mon chardev=char0,mode=readline \ 3084 -serial chardev:char0 \ 3085 -serial chardev:char0 3086 3087 You can have more than one multiplexer in a system configuration; 3088 for instance you could have a TCP port multiplexed between UART 0 3089 and UART 1, and stdio multiplexed between the QEMU monitor and a 3090 parallel port: 3091 3092 :: 3093 3094 -chardev stdio,mux=on,id=char0 \ 3095 -mon chardev=char0,mode=readline \ 3096 -parallel chardev:char0 \ 3097 -chardev tcp,...,mux=on,id=char1 \ 3098 -serial chardev:char1 \ 3099 -serial chardev:char1 3100 3101 When you're using a multiplexed character device, some escape 3102 sequences are interpreted in the input. See the chapter about 3103 :ref:`keys in the character backend multiplexer` in the 3104 System Emulation Users Guide for more details. 3105 3106 Note that some other command line options may implicitly create 3107 multiplexed character backends; for instance ``-serial mon:stdio`` 3108 creates a multiplexed stdio backend connected to the serial port and 3109 the QEMU monitor, and ``-nographic`` also multiplexes the console 3110 and the monitor to stdio. 3111 3112 There is currently no support for multiplexing in the other 3113 direction (where a single QEMU front end takes input and output from 3114 multiple chardevs). 3115 3116 Every backend supports the ``logfile`` option, which supplies the 3117 path to a file to record all data transmitted via the backend. The 3118 ``logappend`` option controls whether the log file will be truncated 3119 or appended to when opened. 3120 3121The available backends are: 3122 3123``-chardev null,id=id`` 3124 A void device. This device will not emit any data, and will drop any 3125 data it receives. The null backend does not take any options. 3126 3127``-chardev socket,id=id[,TCP options or unix options][,server][,nowait][,telnet][,websocket][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3128 Create a two-way stream socket, which can be either a TCP or a unix 3129 socket. A unix socket will be created if ``path`` is specified. 3130 Behaviour is undefined if TCP options are specified for a unix 3131 socket. 3132 3133 ``server`` specifies that the socket shall be a listening socket. 3134 3135 ``nowait`` specifies that QEMU should not block waiting for a client 3136 to connect to a listening socket. 3137 3138 ``telnet`` specifies that traffic on the socket should interpret 3139 telnet escape sequences. 3140 3141 ``websocket`` specifies that the socket uses WebSocket protocol for 3142 communication. 3143 3144 ``reconnect`` sets the timeout for reconnecting on non-server 3145 sockets when the remote end goes away. qemu will delay this many 3146 seconds and then attempt to reconnect. Zero disables reconnecting, 3147 and is the default. 3148 3149 ``tls-creds`` requests enablement of the TLS protocol for 3150 encryption, and specifies the id of the TLS credentials to use for 3151 the handshake. The credentials must be previously created with the 3152 ``-object tls-creds`` argument. 3153 3154 ``tls-auth`` provides the ID of the QAuthZ authorization object 3155 against which the client's x509 distinguished name will be 3156 validated. This object is only resolved at time of use, so can be 3157 deleted and recreated on the fly while the chardev server is active. 3158 If missing, it will default to denying access. 3159 3160 TCP and unix socket options are given below: 3161 3162 ``TCP options: port=port[,host=host][,to=to][,ipv4][,ipv6][,nodelay]`` 3163 ``host`` for a listening socket specifies the local address to 3164 be bound. For a connecting socket species the remote host to 3165 connect to. ``host`` is optional for listening sockets. If not 3166 specified it defaults to ``0.0.0.0``. 3167 3168 ``port`` for a listening socket specifies the local port to be 3169 bound. For a connecting socket specifies the port on the remote 3170 host to connect to. ``port`` can be given as either a port 3171 number or a service name. ``port`` is required. 3172 3173 ``to`` is only relevant to listening sockets. If it is 3174 specified, and ``port`` cannot be bound, QEMU will attempt to 3175 bind to subsequent ports up to and including ``to`` until it 3176 succeeds. ``to`` must be specified as a port number. 3177 3178 ``ipv4`` and ``ipv6`` specify that either IPv4 or IPv6 must be 3179 used. If neither is specified the socket may use either 3180 protocol. 3181 3182 ``nodelay`` disables the Nagle algorithm. 3183 3184 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3185 ``path`` specifies the local path of the unix socket. ``path`` 3186 is required. 3187 ``abstract`` specifies the use of the abstract socket namespace, 3188 rather than the filesystem. Optional, defaults to false. 3189 ``tight`` sets the socket length of abstract sockets to their minimum, 3190 rather than the full sun_path length. Optional, defaults to true. 3191 3192``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4][,ipv6]`` 3193 Sends all traffic from the guest to a remote host over UDP. 3194 3195 ``host`` specifies the remote host to connect to. If not specified 3196 it defaults to ``localhost``. 3197 3198 ``port`` specifies the port on the remote host to connect to. 3199 ``port`` is required. 3200 3201 ``localaddr`` specifies the local address to bind to. If not 3202 specified it defaults to ``0.0.0.0``. 3203 3204 ``localport`` specifies the local port to bind to. If not specified 3205 any available local port will be used. 3206 3207 ``ipv4`` and ``ipv6`` specify that either IPv4 or IPv6 must be used. 3208 If neither is specified the device may use either protocol. 3209 3210``-chardev msmouse,id=id`` 3211 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3212 does not take any options. 3213 3214``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3215 Connect to a QEMU text console. ``vc`` may optionally be given a 3216 specific size. 3217 3218 ``width`` and ``height`` specify the width and height respectively 3219 of the console, in pixels. 3220 3221 ``cols`` and ``rows`` specify that the console be sized to fit a 3222 text console with the given dimensions. 3223 3224``-chardev ringbuf,id=id[,size=size]`` 3225 Create a ring buffer with fixed size ``size``. size must be a power 3226 of two and defaults to ``64K``. 3227 3228``-chardev file,id=id,path=path`` 3229 Log all traffic received from the guest to a file. 3230 3231 ``path`` specifies the path of the file to be opened. This file will 3232 be created if it does not already exist, and overwritten if it does. 3233 ``path`` is required. 3234 3235``-chardev pipe,id=id,path=path`` 3236 Create a two-way connection to the guest. The behaviour differs 3237 slightly between Windows hosts and other hosts: 3238 3239 On Windows, a single duplex pipe will be created at 3240 ``\\.pipe\path``. 3241 3242 On other hosts, 2 pipes will be created called ``path.in`` and 3243 ``path.out``. Data written to ``path.in`` will be received by the 3244 guest. Data written by the guest can be read from ``path.out``. QEMU 3245 will not create these fifos, and requires them to be present. 3246 3247 ``path`` forms part of the pipe path as described above. ``path`` is 3248 required. 3249 3250``-chardev console,id=id`` 3251 Send traffic from the guest to QEMU's standard output. ``console`` 3252 does not take any options. 3253 3254 ``console`` is only available on Windows hosts. 3255 3256``-chardev serial,id=id,path=path`` 3257 Send traffic from the guest to a serial device on the host. 3258 3259 On Unix hosts serial will actually accept any tty device, not only 3260 serial lines. 3261 3262 ``path`` specifies the name of the serial device to open. 3263 3264``-chardev pty,id=id`` 3265 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3266 does not take any options. 3267 3268 ``pty`` is not available on Windows hosts. 3269 3270``-chardev stdio,id=id[,signal=on|off]`` 3271 Connect to standard input and standard output of the QEMU process. 3272 3273 ``signal`` controls if signals are enabled on the terminal, that 3274 includes exiting QEMU with the key sequence Control-c. This option 3275 is enabled by default, use ``signal=off`` to disable it. 3276 3277``-chardev braille,id=id`` 3278 Connect to a local BrlAPI server. ``braille`` does not take any 3279 options. 3280 3281``-chardev tty,id=id,path=path`` 3282 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3283 and DragonFlyBSD hosts. It is an alias for ``serial``. 3284 3285 ``path`` specifies the path to the tty. ``path`` is required. 3286 3287``-chardev parallel,id=id,path=path`` 3288 \ 3289``-chardev parport,id=id,path=path`` 3290 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3291 hosts. 3292 3293 Connect to a local parallel port. 3294 3295 ``path`` specifies the path to the parallel port device. ``path`` is 3296 required. 3297 3298``-chardev spicevmc,id=id,debug=debug,name=name`` 3299 ``spicevmc`` is only available when spice support is built in. 3300 3301 ``debug`` debug level for spicevmc 3302 3303 ``name`` name of spice channel to connect to 3304 3305 Connect to a spice virtual machine channel, such as vdiport. 3306 3307``-chardev spiceport,id=id,debug=debug,name=name`` 3308 ``spiceport`` is only available when spice support is built in. 3309 3310 ``debug`` debug level for spicevmc 3311 3312 ``name`` name of spice port to connect to 3313 3314 Connect to a spice port, allowing a Spice client to handle the 3315 traffic identified by a name (preferably a fqdn). 3316ERST 3317 3318DEFHEADING() 3319 3320#ifdef CONFIG_TPM 3321DEFHEADING(TPM device options:) 3322 3323DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3324 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3325 " use path to provide path to a character device; default is /dev/tpm0\n" 3326 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3327 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3328 "-tpmdev emulator,id=id,chardev=dev\n" 3329 " configure the TPM device using chardev backend\n", 3330 QEMU_ARCH_ALL) 3331SRST 3332The general form of a TPM device option is: 3333 3334``-tpmdev backend,id=id[,options]`` 3335 The specific backend type will determine the applicable options. The 3336 ``-tpmdev`` option creates the TPM backend and requires a 3337 ``-device`` option that specifies the TPM frontend interface model. 3338 3339 Use ``-tpmdev help`` to print all available TPM backend types. 3340 3341The available backends are: 3342 3343``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3344 (Linux-host only) Enable access to the host's TPM using the 3345 passthrough driver. 3346 3347 ``path`` specifies the path to the host's TPM device, i.e., on a 3348 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3349 default ``/dev/tpm0`` is used. 3350 3351 ``cancel-path`` specifies the path to the host TPM device's sysfs 3352 entry allowing for cancellation of an ongoing TPM command. 3353 ``cancel-path`` is optional and by default QEMU will search for the 3354 sysfs entry to use. 3355 3356 Some notes about using the host's TPM with the passthrough driver: 3357 3358 The TPM device accessed by the passthrough driver must not be used 3359 by any other application on the host. 3360 3361 Since the host's firmware (BIOS/UEFI) has already initialized the 3362 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3363 the TPM again and may therefore not show a TPM-specific menu that 3364 would otherwise allow the user to configure the TPM, e.g., allow the 3365 user to enable/disable or activate/deactivate the TPM. Further, if 3366 TPM ownership is released from within a VM then the host's TPM will 3367 get disabled and deactivated. To enable and activate the TPM again 3368 afterwards, the host has to be rebooted and the user is required to 3369 enter the firmware's menu to enable and activate the TPM. If the TPM 3370 is left disabled and/or deactivated most TPM commands will fail. 3371 3372 To create a passthrough TPM use the following two options: 3373 3374 :: 3375 3376 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3377 3378 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3379 ``tpmdev=tpm0`` in the device option. 3380 3381``-tpmdev emulator,id=id,chardev=dev`` 3382 (Linux-host only) Enable access to a TPM emulator using Unix domain 3383 socket based chardev backend. 3384 3385 ``chardev`` specifies the unique ID of a character device backend 3386 that provides connection to the software TPM server. 3387 3388 To create a TPM emulator backend device with chardev socket backend: 3389 3390 :: 3391 3392 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3393ERST 3394 3395DEFHEADING() 3396 3397#endif 3398 3399DEFHEADING(Linux/Multiboot boot specific:) 3400SRST 3401When using these options, you can use a given Linux or Multiboot kernel 3402without installing it in the disk image. It can be useful for easier 3403testing of various kernels. 3404 3405 3406ERST 3407 3408DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3409 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3410SRST 3411``-kernel bzImage`` 3412 Use bzImage as kernel image. The kernel can be either a Linux kernel 3413 or in multiboot format. 3414ERST 3415 3416DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3417 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3418SRST 3419``-append cmdline`` 3420 Use cmdline as kernel command line 3421ERST 3422 3423DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3424 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3425SRST 3426``-initrd file`` 3427 Use file as initial ram disk. 3428 3429``-initrd "file1 arg=foo,file2"`` 3430 This syntax is only available with multiboot. 3431 3432 Use file1 and file2 as modules and pass arg=foo as parameter to the 3433 first module. 3434ERST 3435 3436DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3437 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3438SRST 3439``-dtb file`` 3440 Use file as a device tree binary (dtb) image and pass it to the 3441 kernel on boot. 3442ERST 3443 3444DEFHEADING() 3445 3446DEFHEADING(Debug/Expert options:) 3447 3448DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3449 "-fw_cfg [name=]<name>,file=<file>\n" 3450 " add named fw_cfg entry with contents from file\n" 3451 "-fw_cfg [name=]<name>,string=<str>\n" 3452 " add named fw_cfg entry with contents from string\n", 3453 QEMU_ARCH_ALL) 3454SRST 3455``-fw_cfg [name=]name,file=file`` 3456 Add named fw\_cfg entry with contents from file file. 3457 3458``-fw_cfg [name=]name,string=str`` 3459 Add named fw\_cfg entry with contents from string str. 3460 3461 The terminating NUL character of the contents of str will not be 3462 included as part of the fw\_cfg item data. To insert contents with 3463 embedded NUL characters, you have to use the file parameter. 3464 3465 The fw\_cfg entries are passed by QEMU through to the guest. 3466 3467 Example: 3468 3469 :: 3470 3471 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3472 3473 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3474 from ./my\_blob.bin. 3475ERST 3476 3477DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3478 "-serial dev redirect the serial port to char device 'dev'\n", 3479 QEMU_ARCH_ALL) 3480SRST 3481``-serial dev`` 3482 Redirect the virtual serial port to host character device dev. The 3483 default device is ``vc`` in graphical mode and ``stdio`` in non 3484 graphical mode. 3485 3486 This option can be used several times to simulate up to 4 serial 3487 ports. 3488 3489 Use ``-serial none`` to disable all serial ports. 3490 3491 Available character devices are: 3492 3493 ``vc[:WxH]`` 3494 Virtual console. Optionally, a width and height can be given in 3495 pixel with 3496 3497 :: 3498 3499 vc:800x600 3500 3501 It is also possible to specify width or height in characters: 3502 3503 :: 3504 3505 vc:80Cx24C 3506 3507 ``pty`` 3508 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3509 3510 ``none`` 3511 No device is allocated. 3512 3513 ``null`` 3514 void device 3515 3516 ``chardev:id`` 3517 Use a named character device defined with the ``-chardev`` 3518 option. 3519 3520 ``/dev/XXX`` 3521 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3522 port parameters are set according to the emulated ones. 3523 3524 ``/dev/parportN`` 3525 [Linux only, parallel port only] Use host parallel port N. 3526 Currently SPP and EPP parallel port features can be used. 3527 3528 ``file:filename`` 3529 Write output to filename. No character can be read. 3530 3531 ``stdio`` 3532 [Unix only] standard input/output 3533 3534 ``pipe:filename`` 3535 name pipe filename 3536 3537 ``COMn`` 3538 [Windows only] Use host serial port n 3539 3540 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3541 This implements UDP Net Console. When remote\_host or src\_ip 3542 are not specified they default to ``0.0.0.0``. When not using a 3543 specified src\_port a random port is automatically chosen. 3544 3545 If you just want a simple readonly console you can use 3546 ``netcat`` or ``nc``, by starting QEMU with: 3547 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3548 QEMU writes something to that port it will appear in the 3549 netconsole session. 3550 3551 If you plan to send characters back via netconsole or you want 3552 to stop and start QEMU a lot of times, you should have QEMU use 3553 the same source port each time by using something like ``-serial 3554 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3555 version of netcat which can listen to a TCP port and send and 3556 receive characters via udp. If you have a patched version of 3557 netcat which activates telnet remote echo and single char 3558 transfer, then you can use the following options to set up a 3559 netcat redirector to allow telnet on port 5555 to access the 3560 QEMU port. 3561 3562 ``QEMU Options:`` 3563 -serial udp::4555@:4556 3564 3565 ``netcat options:`` 3566 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3567 3568 ``telnet options:`` 3569 localhost 5555 3570 3571 ``tcp:[host]:port[,server][,nowait][,nodelay][,reconnect=seconds]`` 3572 The TCP Net Console has two modes of operation. It can send the 3573 serial I/O to a location or wait for a connection from a 3574 location. By default the TCP Net Console is sent to host at the 3575 port. If you use the server option QEMU will wait for a client 3576 socket application to connect to the port before continuing, 3577 unless the ``nowait`` option was specified. The ``nodelay`` 3578 option disables the Nagle buffering algorithm. The ``reconnect`` 3579 option only applies if noserver is set, if the connection goes 3580 down it will attempt to reconnect at the given interval. If host 3581 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3582 time is accepted. You can use ``telnet`` to connect to the 3583 corresponding character device. 3584 3585 ``Example to send tcp console to 192.168.0.2 port 4444`` 3586 -serial tcp:192.168.0.2:4444 3587 3588 ``Example to listen and wait on port 4444 for connection`` 3589 -serial tcp::4444,server 3590 3591 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3592 -serial tcp:192.168.0.100:4444,server,nowait 3593 3594 ``telnet:host:port[,server][,nowait][,nodelay]`` 3595 The telnet protocol is used instead of raw tcp sockets. The 3596 options work the same as if you had specified ``-serial tcp``. 3597 The difference is that the port acts like a telnet server or 3598 client using telnet option negotiation. This will also allow you 3599 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3600 supports sending the break sequence. Typically in unix telnet 3601 you do it with Control-] and then type "send break" followed by 3602 pressing the enter key. 3603 3604 ``websocket:host:port,server[,nowait][,nodelay]`` 3605 The WebSocket protocol is used instead of raw tcp socket. The 3606 port acts as a WebSocket server. Client mode is not supported. 3607 3608 ``unix:path[,server][,nowait][,reconnect=seconds]`` 3609 A unix domain socket is used instead of a tcp socket. The option 3610 works the same as if you had specified ``-serial tcp`` except 3611 the unix domain socket path is used for connections. 3612 3613 ``mon:dev_string`` 3614 This is a special option to allow the monitor to be multiplexed 3615 onto another serial port. The monitor is accessed with key 3616 sequence of Control-a and then pressing c. dev\_string should be 3617 any one of the serial devices specified above. An example to 3618 multiplex the monitor onto a telnet server listening on port 3619 4444 would be: 3620 3621 ``-serial mon:telnet::4444,server,nowait`` 3622 3623 When the monitor is multiplexed to stdio in this way, Ctrl+C 3624 will not terminate QEMU any more but will be passed to the guest 3625 instead. 3626 3627 ``braille`` 3628 Braille device. This will use BrlAPI to display the braille 3629 output on a real or fake device. 3630 3631 ``msmouse`` 3632 Three button serial mouse. Configure the guest to use Microsoft 3633 protocol. 3634ERST 3635 3636DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3637 "-parallel dev redirect the parallel port to char device 'dev'\n", 3638 QEMU_ARCH_ALL) 3639SRST 3640``-parallel dev`` 3641 Redirect the virtual parallel port to host device dev (same devices 3642 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3643 to use hardware devices connected on the corresponding host parallel 3644 port. 3645 3646 This option can be used several times to simulate up to 3 parallel 3647 ports. 3648 3649 Use ``-parallel none`` to disable all parallel ports. 3650ERST 3651 3652DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3653 "-monitor dev redirect the monitor to char device 'dev'\n", 3654 QEMU_ARCH_ALL) 3655SRST 3656``-monitor dev`` 3657 Redirect the monitor to host device dev (same devices as the serial 3658 port). The default device is ``vc`` in graphical mode and ``stdio`` 3659 in non graphical mode. Use ``-monitor none`` to disable the default 3660 monitor. 3661ERST 3662DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3663 "-qmp dev like -monitor but opens in 'control' mode\n", 3664 QEMU_ARCH_ALL) 3665SRST 3666``-qmp dev`` 3667 Like -monitor but opens in 'control' mode. 3668ERST 3669DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3670 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3671 QEMU_ARCH_ALL) 3672SRST 3673``-qmp-pretty dev`` 3674 Like -qmp but uses pretty JSON formatting. 3675ERST 3676 3677DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3678 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3679SRST 3680``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3681 Setup monitor on chardev name. ``pretty`` turns on JSON pretty 3682 printing easing human reading and debugging. 3683ERST 3684 3685DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3686 "-debugcon dev redirect the debug console to char device 'dev'\n", 3687 QEMU_ARCH_ALL) 3688SRST 3689``-debugcon dev`` 3690 Redirect the debug console to host device dev (same devices as the 3691 serial port). The debug console is an I/O port which is typically 3692 port 0xe9; writing to that I/O port sends output to this device. The 3693 default device is ``vc`` in graphical mode and ``stdio`` in non 3694 graphical mode. 3695ERST 3696 3697DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3698 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3699SRST 3700``-pidfile file`` 3701 Store the QEMU process PID in file. It is useful if you launch QEMU 3702 from a script. 3703ERST 3704 3705DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3706 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3707SRST 3708``-singlestep`` 3709 Run the emulation in single step mode. 3710ERST 3711 3712DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3713 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3714 QEMU_ARCH_ALL) 3715SRST 3716``--preconfig`` 3717 Pause QEMU for interactive configuration before the machine is 3718 created, which allows querying and configuring properties that will 3719 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3720 exit the preconfig state and move to the next state (i.e. run guest 3721 if -S isn't used or pause the second time if -S is used). This 3722 option is experimental. 3723ERST 3724 3725DEF("S", 0, QEMU_OPTION_S, \ 3726 "-S freeze CPU at startup (use 'c' to start execution)\n", 3727 QEMU_ARCH_ALL) 3728SRST 3729``-S`` 3730 Do not start CPU at startup (you must type 'c' in the monitor). 3731ERST 3732 3733DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3734 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3735 " run qemu with overcommit hints\n" 3736 " mem-lock=on|off controls memory lock support (default: off)\n" 3737 " cpu-pm=on|off controls cpu power management (default: off)\n", 3738 QEMU_ARCH_ALL) 3739SRST 3740``-overcommit mem-lock=on|off`` 3741 \ 3742``-overcommit cpu-pm=on|off`` 3743 Run qemu with hints about host resource overcommit. The default is 3744 to assume that host overcommits all resources. 3745 3746 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3747 (disabled by default). This works when host memory is not 3748 overcommitted and reduces the worst-case latency for guest. 3749 3750 Guest ability to manage power state of host cpus (increasing latency 3751 for other processes on the same host cpu, but decreasing latency for 3752 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3753 works best when host CPU is not overcommitted. When used, host 3754 estimates of CPU cycle and power utilization will be incorrect, not 3755 taking into account guest idle time. 3756ERST 3757 3758DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3759 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3760 " the guest without waiting for gdb to connect; use -S too\n" 3761 " if you want it to not start execution.)\n", 3762 QEMU_ARCH_ALL) 3763SRST 3764``-gdb dev`` 3765 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3766 in the System Emulation Users Guide). Note that this option does not pause QEMU 3767 execution -- if you want QEMU to not start the guest until you 3768 connect with gdb and issue a ``continue`` command, you will need to 3769 also pass the ``-S`` option to QEMU. 3770 3771 The most usual configuration is to listen on a local TCP socket:: 3772 3773 -gdb tcp::3117 3774 3775 but you can specify other backends; UDP, pseudo TTY, or even stdio 3776 are all reasonable use cases. For example, a stdio connection 3777 allows you to start QEMU from within gdb and establish the 3778 connection via a pipe: 3779 3780 .. parsed-literal:: 3781 3782 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3783ERST 3784 3785DEF("s", 0, QEMU_OPTION_s, \ 3786 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3787 QEMU_ARCH_ALL) 3788SRST 3789``-s`` 3790 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3791 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3792ERST 3793 3794DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3795 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3796 QEMU_ARCH_ALL) 3797SRST 3798``-d item1[,...]`` 3799 Enable logging of specified items. Use '-d help' for a list of log 3800 items. 3801ERST 3802 3803DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3804 "-D logfile output log to logfile (default stderr)\n", 3805 QEMU_ARCH_ALL) 3806SRST 3807``-D logfile`` 3808 Output log in logfile instead of to stderr 3809ERST 3810 3811DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3812 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3813 QEMU_ARCH_ALL) 3814SRST 3815``-dfilter range1[,...]`` 3816 Filter debug output to that relevant to a range of target addresses. 3817 The filter spec can be either start+size, start-size or start..end 3818 where start end and size are the addresses and sizes required. For 3819 example: 3820 3821 :: 3822 3823 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3824 3825 Will dump output for any code in the 0x1000 sized block starting at 3826 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3827 another 0x1000 sized block starting at 0xffffffc00005f000. 3828ERST 3829 3830DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3831 "-seed number seed the pseudo-random number generator\n", 3832 QEMU_ARCH_ALL) 3833SRST 3834``-seed number`` 3835 Force the guest to use a deterministic pseudo-random number 3836 generator, seeded with number. This does not affect crypto routines 3837 within the host. 3838ERST 3839 3840DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3841 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3842 QEMU_ARCH_ALL) 3843SRST 3844``-L path`` 3845 Set the directory for the BIOS, VGA BIOS and keymaps. 3846 3847 To list all the data directories, use ``-L help``. 3848ERST 3849 3850DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3851 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3852SRST 3853``-bios file`` 3854 Set the filename for the BIOS. 3855ERST 3856 3857DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3858 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3859SRST 3860``-enable-kvm`` 3861 Enable KVM full virtualization support. This option is only 3862 available if KVM support is enabled when compiling. 3863ERST 3864 3865DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3866 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3867DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3868 "-xen-attach attach to existing xen domain\n" 3869 " libxl will use this when starting QEMU\n", 3870 QEMU_ARCH_ALL) 3871DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3872 "-xen-domid-restrict restrict set of available xen operations\n" 3873 " to specified domain id. (Does not affect\n" 3874 " xenpv machine type).\n", 3875 QEMU_ARCH_ALL) 3876SRST 3877``-xen-domid id`` 3878 Specify xen guest domain id (XEN only). 3879 3880``-xen-attach`` 3881 Attach to existing xen domain. libxl will use this when starting 3882 QEMU (XEN only). Restrict set of available xen operations to 3883 specified domain id (XEN only). 3884ERST 3885 3886DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 3887 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 3888SRST 3889``-no-reboot`` 3890 Exit instead of rebooting. 3891ERST 3892 3893DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 3894 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 3895SRST 3896``-no-shutdown`` 3897 Don't exit QEMU on guest shutdown, but instead only stop the 3898 emulation. This allows for instance switching to monitor to commit 3899 changes to the disk image. 3900ERST 3901 3902DEF("action", HAS_ARG, QEMU_OPTION_action, 3903 "-action reboot=reset|shutdown\n" 3904 " action when guest reboots [default=reset]\n" 3905 "-action shutdown=poweroff|pause\n" 3906 " action when guest shuts down [default=poweroff]\n" 3907 "-action panic=pause|shutdown|none\n" 3908 " action when guest panics [default=shutdown]\n" 3909 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 3910 " action when watchdog fires [default=reset]\n", 3911 QEMU_ARCH_ALL) 3912SRST 3913``-action event=action`` 3914 The action parameter serves to modify QEMU's default behavior when 3915 certain guest events occur. It provides a generic method for specifying the 3916 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 3917 parameters. 3918 3919 Examples: 3920 3921 ``-action panic=none`` 3922 ``-action reboot=shutdown,shutdown=pause`` 3923 ``-watchdog i6300esb -action watchdog=pause`` 3924 3925ERST 3926 3927DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 3928 "-loadvm [tag|id]\n" \ 3929 " start right away with a saved state (loadvm in monitor)\n", 3930 QEMU_ARCH_ALL) 3931SRST 3932``-loadvm file`` 3933 Start right away with a saved state (``loadvm`` in monitor) 3934ERST 3935 3936#ifndef _WIN32 3937DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 3938 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 3939#endif 3940SRST 3941``-daemonize`` 3942 Daemonize the QEMU process after initialization. QEMU will not 3943 detach from standard IO until it is ready to receive connections on 3944 any of its devices. This option is a useful way for external 3945 programs to launch QEMU without having to cope with initialization 3946 race conditions. 3947ERST 3948 3949DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 3950 "-option-rom rom load a file, rom, into the option ROM space\n", 3951 QEMU_ARCH_ALL) 3952SRST 3953``-option-rom file`` 3954 Load the contents of file as an option ROM. This option is useful to 3955 load things like EtherBoot. 3956ERST 3957 3958DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 3959 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 3960 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 3961 QEMU_ARCH_ALL) 3962 3963SRST 3964``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 3965 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 3966 the current UTC or local time, respectively. ``localtime`` is 3967 required for correct date in MS-DOS or Windows. To start at a 3968 specific point in time, provide datetime in the format 3969 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 3970 3971 By default the RTC is driven by the host system time. This allows 3972 using of the RTC as accurate reference clock inside the guest, 3973 specifically if the host time is smoothly following an accurate 3974 external reference clock, e.g. via NTP. If you want to isolate the 3975 guest time from the host, you can set ``clock`` to ``rt`` instead, 3976 which provides a host monotonic clock if host support it. To even 3977 prevent the RTC from progressing during suspension, you can set 3978 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 3979 recommended especially in icount mode in order to preserve 3980 determinism; however, note that in icount mode the speed of the 3981 virtual clock is variable and can in general differ from the host 3982 clock. 3983 3984 Enable ``driftfix`` (i386 targets only) if you experience time drift 3985 problems, specifically with Windows' ACPI HAL. This option will try 3986 to figure out how many timer interrupts were not processed by the 3987 Windows guest and will re-inject them. 3988ERST 3989 3990DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 3991 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 3992 " enable virtual instruction counter with 2^N clock ticks per\n" \ 3993 " instruction, enable aligning the host and virtual clocks\n" \ 3994 " or disable real time cpu sleeping, and optionally enable\n" \ 3995 " record-and-replay mode\n", QEMU_ARCH_ALL) 3996SRST 3997``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 3998 Enable virtual instruction counter. The virtual cpu will execute one 3999 instruction every 2^N ns of virtual time. If ``auto`` is specified 4000 then the virtual cpu speed will be automatically adjusted to keep 4001 virtual time within a few seconds of real time. 4002 4003 Note that while this option can give deterministic behavior, it does 4004 not provide cycle accurate emulation. Modern CPUs contain 4005 superscalar out of order cores with complex cache hierarchies. The 4006 number of instructions executed often has little or no correlation 4007 with actual performance. 4008 4009 When the virtual cpu is sleeping, the virtual time will advance at 4010 default speed unless ``sleep=on`` is specified. With 4011 ``sleep=on``, the virtual time will jump to the next timer 4012 deadline instantly whenever the virtual cpu goes to sleep mode and 4013 will not advance if no timer is enabled. This behavior gives 4014 deterministic execution times from the guest point of view. 4015 The default if icount is enabled is ``sleep=off``. 4016 ``sleep=on`` cannot be used together with either ``shift=auto`` 4017 or ``align=on``. 4018 4019 ``align=on`` will activate the delay algorithm which will try to 4020 synchronise the host clock and the virtual clock. The goal is to 4021 have a guest running at the real frequency imposed by the shift 4022 option. Whenever the guest clock is behind the host clock and if 4023 ``align=on`` is specified then we print a message to the user to 4024 inform about the delay. Currently this option does not work when 4025 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4026 shift values for which the guest clock runs ahead of the host clock. 4027 Typically this happens when the shift value is high (how high 4028 depends on the host machine). The default if icount is enabled 4029 is ``align=off``. 4030 4031 When the ``rr`` option is specified deterministic record/replay is 4032 enabled. The ``rrfile=`` option must also be provided to 4033 specify the path to the replay log. In record mode data is written 4034 to this file, and in replay mode it is read back. 4035 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4036 name. In record mode, a new VM snapshot with the given name is created 4037 at the start of execution recording. In replay mode this option 4038 specifies the snapshot name used to load the initial VM state. 4039ERST 4040 4041DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4042 "-watchdog model\n" \ 4043 " enable virtual hardware watchdog [default=none]\n", 4044 QEMU_ARCH_ALL) 4045SRST 4046``-watchdog model`` 4047 Create a virtual hardware watchdog device. Once enabled (by a guest 4048 action), the watchdog must be periodically polled by an agent inside 4049 the guest or else the guest will be restarted. Choose a model for 4050 which your guest has drivers. 4051 4052 The model is the model of hardware watchdog to emulate. Use 4053 ``-watchdog help`` to list available hardware models. Only one 4054 watchdog can be enabled for a guest. 4055 4056 The following models may be available: 4057 4058 ``ib700`` 4059 iBASE 700 is a very simple ISA watchdog with a single timer. 4060 4061 ``i6300esb`` 4062 Intel 6300ESB I/O controller hub is a much more featureful 4063 PCI-based dual-timer watchdog. 4064 4065 ``diag288`` 4066 A virtual watchdog for s390x backed by the diagnose 288 4067 hypercall (currently KVM only). 4068ERST 4069 4070DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4071 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4072 " action when watchdog fires [default=reset]\n", 4073 QEMU_ARCH_ALL) 4074SRST 4075``-watchdog-action action`` 4076 The action controls what QEMU will do when the watchdog timer 4077 expires. The default is ``reset`` (forcefully reset the guest). 4078 Other possible actions are: ``shutdown`` (attempt to gracefully 4079 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4080 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4081 guest), ``debug`` (print a debug message and continue), or ``none`` 4082 (do nothing). 4083 4084 Note that the ``shutdown`` action requires that the guest responds 4085 to ACPI signals, which it may not be able to do in the sort of 4086 situations where the watchdog would have expired, and thus 4087 ``-watchdog-action shutdown`` is not recommended for production use. 4088 4089 Examples: 4090 4091 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4092 4093ERST 4094 4095DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4096 "-echr chr set terminal escape character instead of ctrl-a\n", 4097 QEMU_ARCH_ALL) 4098SRST 4099``-echr numeric_ascii_value`` 4100 Change the escape character used for switching to the monitor when 4101 using monitor and serial sharing. The default is ``0x01`` when using 4102 the ``-nographic`` option. ``0x01`` is equal to pressing 4103 ``Control-a``. You can select a different character from the ascii 4104 control keys where 1 through 26 map to Control-a through Control-z. 4105 For instance you could use the either of the following to change the 4106 escape character to Control-t. 4107 4108 ``-echr 0x14``; \ ``-echr 20`` 4109 4110ERST 4111 4112DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4113 "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \ 4114 "-incoming rdma:host:port[,ipv4][,ipv6]\n" \ 4115 "-incoming unix:socketpath\n" \ 4116 " prepare for incoming migration, listen on\n" \ 4117 " specified protocol and socket address\n" \ 4118 "-incoming fd:fd\n" \ 4119 "-incoming exec:cmdline\n" \ 4120 " accept incoming migration on given file descriptor\n" \ 4121 " or from given external command\n" \ 4122 "-incoming defer\n" \ 4123 " wait for the URI to be specified via migrate_incoming\n", 4124 QEMU_ARCH_ALL) 4125SRST 4126``-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]`` 4127 \ 4128``-incoming rdma:host:port[,ipv4][,ipv6]`` 4129 Prepare for incoming migration, listen on a given tcp port. 4130 4131``-incoming unix:socketpath`` 4132 Prepare for incoming migration, listen on a given unix socket. 4133 4134``-incoming fd:fd`` 4135 Accept incoming migration from a given filedescriptor. 4136 4137``-incoming exec:cmdline`` 4138 Accept incoming migration as an output from specified external 4139 command. 4140 4141``-incoming defer`` 4142 Wait for the URI to be specified via migrate\_incoming. The monitor 4143 can be used to change settings (such as migration parameters) prior 4144 to issuing the migrate\_incoming to allow the migration to begin. 4145ERST 4146 4147DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4148 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4149SRST 4150``-only-migratable`` 4151 Only allow migratable devices. Devices will not be allowed to enter 4152 an unmigratable state. 4153ERST 4154 4155DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4156 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4157SRST 4158``-nodefaults`` 4159 Don't create default devices. Normally, QEMU sets the default 4160 devices like serial port, parallel port, virtual console, monitor 4161 device, VGA adapter, floppy and CD-ROM drive and others. The 4162 ``-nodefaults`` option will disable all those default devices. 4163ERST 4164 4165#ifndef _WIN32 4166DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4167 "-chroot dir chroot to dir just before starting the VM\n", 4168 QEMU_ARCH_ALL) 4169#endif 4170SRST 4171``-chroot dir`` 4172 Immediately before starting guest execution, chroot to the specified 4173 directory. Especially useful in combination with -runas. 4174ERST 4175 4176#ifndef _WIN32 4177DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4178 "-runas user change to user id user just before starting the VM\n" \ 4179 " user can be numeric uid:gid instead\n", 4180 QEMU_ARCH_ALL) 4181#endif 4182SRST 4183``-runas user`` 4184 Immediately before starting guest execution, drop root privileges, 4185 switching to the specified user. 4186ERST 4187 4188DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4189 "-prom-env variable=value\n" 4190 " set OpenBIOS nvram variables\n", 4191 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4192SRST 4193``-prom-env variable=value`` 4194 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4195 4196 :: 4197 4198 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4199 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4200 4201 :: 4202 4203 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4204 -prom-env 'boot-device=hd:2,\yaboot' \ 4205 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4206ERST 4207DEF("semihosting", 0, QEMU_OPTION_semihosting, 4208 "-semihosting semihosting mode\n", 4209 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4210 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4211SRST 4212``-semihosting`` 4213 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4214 4215 Note that this allows guest direct access to the host filesystem, so 4216 should only be used with a trusted guest OS. 4217 4218 See the -semihosting-config option documentation for further 4219 information about the facilities this enables. 4220ERST 4221DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4222 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4223 " semihosting configuration\n", 4224QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4225QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4226SRST 4227``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4228 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4229 only). 4230 4231 Note that this allows guest direct access to the host filesystem, so 4232 should only be used with a trusted guest OS. 4233 4234 On Arm this implements the standard semihosting API, version 2.0. 4235 4236 On M68K this implements the "ColdFire GDB" interface used by 4237 libgloss. 4238 4239 Xtensa semihosting provides basic file IO calls, such as 4240 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4241 linux platform "sim" use this interface. 4242 4243 On RISC-V this implements the standard semihosting API, version 0.2. 4244 4245 ``target=native|gdb|auto`` 4246 Defines where the semihosting calls will be addressed, to QEMU 4247 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4248 means ``gdb`` during debug sessions and ``native`` otherwise. 4249 4250 ``chardev=str1`` 4251 Send the output to a chardev backend output for native or auto 4252 output when not in gdb 4253 4254 ``arg=str1,arg=str2,...`` 4255 Allows the user to pass input arguments, and can be used 4256 multiple times to build up a list. The old-style 4257 ``-kernel``/``-append`` method of passing a command line is 4258 still supported for backward compatibility. If both the 4259 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4260 specified, the former is passed to semihosting as it always 4261 takes precedence. 4262ERST 4263DEF("old-param", 0, QEMU_OPTION_old_param, 4264 "-old-param old param mode\n", QEMU_ARCH_ARM) 4265SRST 4266``-old-param`` 4267 Old param mode (ARM only). 4268ERST 4269 4270DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4271 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4272 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4273 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4274 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4275 " by the kernel, but typically no longer used by modern\n" \ 4276 " C library implementations.\n" \ 4277 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \ 4278 " its privileges by blacklisting all set*uid|gid system calls.\n" \ 4279 " The value 'children' will deny set*uid|gid system calls for\n" \ 4280 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4281 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4282 " blacklisting *fork and execve\n" \ 4283 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4284 QEMU_ARCH_ALL) 4285SRST 4286``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4287 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4288 filtering and 'off' will disable it. The default is 'off'. 4289 4290 ``obsolete=string`` 4291 Enable Obsolete system calls 4292 4293 ``elevateprivileges=string`` 4294 Disable set\*uid\|gid system calls 4295 4296 ``spawn=string`` 4297 Disable \*fork and execve 4298 4299 ``resourcecontrol=string`` 4300 Disable process affinity and schedular priority 4301ERST 4302 4303DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4304 "-readconfig <file>\n", QEMU_ARCH_ALL) 4305SRST 4306``-readconfig file`` 4307 Read device configuration from file. This approach is useful when 4308 you want to spawn QEMU process with many command line options but 4309 you don't want to exceed the command line character limit. 4310ERST 4311DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4312 "-writeconfig <file>\n" 4313 " read/write config file\n", QEMU_ARCH_ALL) 4314SRST 4315``-writeconfig file`` 4316 Write device configuration to file. The file can be either filename 4317 to save command line and device configuration into file or dash 4318 ``-``) character to print the output to stdout. This can be later 4319 used as input file for ``-readconfig`` option. 4320ERST 4321 4322DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4323 "-no-user-config\n" 4324 " do not load default user-provided config files at startup\n", 4325 QEMU_ARCH_ALL) 4326SRST 4327``-no-user-config`` 4328 The ``-no-user-config`` option makes QEMU not load any of the 4329 user-provided config files on sysconfdir. 4330ERST 4331 4332DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4333 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4334 " specify tracing options\n", 4335 QEMU_ARCH_ALL) 4336SRST 4337``-trace [[enable=]pattern][,events=file][,file=file]`` 4338 .. include:: ../qemu-option-trace.rst.inc 4339 4340ERST 4341DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4342 "-plugin [file=]<file>[,arg=<string>]\n" 4343 " load a plugin\n", 4344 QEMU_ARCH_ALL) 4345SRST 4346``-plugin file=file[,arg=string]`` 4347 Load a plugin. 4348 4349 ``file=file`` 4350 Load the given plugin from a shared library file. 4351 4352 ``arg=string`` 4353 Argument string passed to the plugin. (Can be given multiple 4354 times.) 4355ERST 4356 4357HXCOMM Internal use 4358DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4359DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4360 4361#ifdef __linux__ 4362DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4363 "-enable-fips enable FIPS 140-2 compliance\n", 4364 QEMU_ARCH_ALL) 4365#endif 4366SRST 4367``-enable-fips`` 4368 Enable FIPS 140-2 compliance mode. 4369ERST 4370 4371DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4372 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4373 " control error message format\n" 4374 " timestamp=on enables timestamps (default: off)\n" 4375 " guest-name=on enables guest name prefix but only if\n" 4376 " -name guest option is set (default: off)\n", 4377 QEMU_ARCH_ALL) 4378SRST 4379``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4380 Control error message format. 4381 4382 ``timestamp=on|off`` 4383 Prefix messages with a timestamp. Default is off. 4384 4385 ``guest-name=on|off`` 4386 Prefix messages with guest name but only if -name guest option is set 4387 otherwise the option is ignored. Default is off. 4388ERST 4389 4390DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4391 "-dump-vmstate <file>\n" 4392 " Output vmstate information in JSON format to file.\n" 4393 " Use the scripts/vmstate-static-checker.py file to\n" 4394 " check for possible regressions in migration code\n" 4395 " by comparing two such vmstate dumps.\n", 4396 QEMU_ARCH_ALL) 4397SRST 4398``-dump-vmstate file`` 4399 Dump json-encoded vmstate information for current machine type to 4400 file in file 4401ERST 4402 4403DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4404 "-enable-sync-profile\n" 4405 " enable synchronization profiling\n", 4406 QEMU_ARCH_ALL) 4407SRST 4408``-enable-sync-profile`` 4409 Enable synchronization profiling. 4410ERST 4411 4412DEFHEADING() 4413 4414DEFHEADING(Generic object creation:) 4415 4416DEF("object", HAS_ARG, QEMU_OPTION_object, 4417 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4418 " create a new object of type TYPENAME setting properties\n" 4419 " in the order they are specified. Note that the 'id'\n" 4420 " property must be set. These objects are placed in the\n" 4421 " '/objects' path.\n", 4422 QEMU_ARCH_ALL) 4423SRST 4424``-object typename[,prop1=value1,...]`` 4425 Create a new object of type typename setting properties in the order 4426 they are specified. Note that the 'id' property must be set. These 4427 objects are placed in the '/objects' path. 4428 4429 ``-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`` 4430 Creates a memory file backend object, which can be used to back 4431 the guest RAM with huge pages. 4432 4433 The ``id`` parameter is a unique ID that will be used to 4434 reference this memory region when configuring the ``-numa`` 4435 argument. 4436 4437 The ``size`` option provides the size of the memory region, and 4438 accepts common suffixes, eg ``500M``. 4439 4440 The ``mem-path`` provides the path to either a shared memory or 4441 huge page filesystem mount. 4442 4443 The ``share`` boolean option determines whether the memory 4444 region is marked as private to QEMU, or shared. The latter 4445 allows a co-operating external process to access the QEMU memory 4446 region. 4447 4448 The ``share`` is also required for pvrdma devices due to 4449 limitations in the RDMA API provided by Linux. 4450 4451 Setting share=on might affect the ability to configure NUMA 4452 bindings for the memory backend under some circumstances, see 4453 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4454 source tree for additional details. 4455 4456 Setting the ``discard-data`` boolean option to on indicates that 4457 file contents can be destroyed when QEMU exits, to avoid 4458 unnecessarily flushing data to the backing file. Note that 4459 ``discard-data`` is only an optimization, and QEMU might not 4460 discard file contents if it aborts unexpectedly or is terminated 4461 using SIGKILL. 4462 4463 The ``merge`` boolean option enables memory merge, also known as 4464 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4465 the pages for memory deduplication. 4466 4467 Setting the ``dump`` boolean option to off excludes the memory 4468 from core dumps. This feature is also known as MADV\_DONTDUMP. 4469 4470 The ``prealloc`` boolean option enables memory preallocation. 4471 4472 The ``host-nodes`` option binds the memory range to a list of 4473 NUMA host nodes. 4474 4475 The ``policy`` option sets the NUMA policy to one of the 4476 following values: 4477 4478 ``default`` 4479 default host policy 4480 4481 ``preferred`` 4482 prefer the given host node list for allocation 4483 4484 ``bind`` 4485 restrict memory allocation to the given host node list 4486 4487 ``interleave`` 4488 interleave memory allocations across the given host node 4489 list 4490 4491 The ``align`` option specifies the base address alignment when 4492 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4493 ``2M``. Some backend store specified by ``mem-path`` requires an 4494 alignment different than the default one used by QEMU, eg the 4495 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4496 such cases, users can specify the required alignment via this 4497 option. 4498 4499 The ``pmem`` option specifies whether the backing file specified 4500 by ``mem-path`` is in host persistent memory that can be 4501 accessed using the SNIA NVM programming model (e.g. Intel 4502 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4503 operations to guarantee the persistence of its own writes to 4504 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4505 migration). Also, we will map the backend-file with MAP\_SYNC 4506 flag, which ensures the file metadata is in sync for 4507 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4508 requires support from both the host kernel (since Linux kernel 4509 4.15) and the filesystem of ``mem-path`` mounted with DAX 4510 option. 4511 4512 The ``readonly`` option specifies whether the backing file is opened 4513 read-only or read-write (default). 4514 4515 ``-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`` 4516 Creates a memory backend object, which can be used to back the 4517 guest RAM. Memory backend objects offer more control than the 4518 ``-m`` option that is traditionally used to define guest RAM. 4519 Please refer to ``memory-backend-file`` for a description of the 4520 options. 4521 4522 ``-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`` 4523 Creates an anonymous memory file backend object, which allows 4524 QEMU to share the memory with an external process (e.g. when 4525 using vhost-user). The memory is allocated with memfd and 4526 optional sealing. (Linux only) 4527 4528 The ``seal`` option creates a sealed-file, that will block 4529 further resizing the memory ('on' by default). 4530 4531 The ``hugetlb`` option specify the file to be created resides in 4532 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4533 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4534 the hugetlb page size on systems that support multiple hugetlb 4535 page sizes (it must be a power of 2 value supported by the 4536 system). 4537 4538 In some versions of Linux, the ``hugetlb`` option is 4539 incompatible with the ``seal`` option (requires at least Linux 4540 4.16). 4541 4542 Please refer to ``memory-backend-file`` for a description of the 4543 other options. 4544 4545 The ``share`` boolean option is on by default with memfd. 4546 4547 ``-object rng-builtin,id=id`` 4548 Creates a random number generator backend which obtains entropy 4549 from QEMU builtin functions. The ``id`` parameter is a unique ID 4550 that will be used to reference this entropy backend from the 4551 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4552 uses this RNG backend. 4553 4554 ``-object rng-random,id=id,filename=/dev/random`` 4555 Creates a random number generator backend which obtains entropy 4556 from a device on the host. The ``id`` parameter is a unique ID 4557 that will be used to reference this entropy backend from the 4558 ``virtio-rng`` device. The ``filename`` parameter specifies 4559 which file to obtain entropy from and if omitted defaults to 4560 ``/dev/urandom``. 4561 4562 ``-object rng-egd,id=id,chardev=chardevid`` 4563 Creates a random number generator backend which obtains entropy 4564 from an external daemon running on the host. The ``id`` 4565 parameter is a unique ID that will be used to reference this 4566 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4567 parameter is the unique ID of a character device backend that 4568 provides the connection to the RNG daemon. 4569 4570 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4571 Creates a TLS anonymous credentials object, which can be used to 4572 provide TLS support on network backends. The ``id`` parameter is 4573 a unique ID which network backends will use to access the 4574 credentials. The ``endpoint`` is either ``server`` or ``client`` 4575 depending on whether the QEMU network backend that uses the 4576 credentials will be acting as a client or as a server. If 4577 ``verify-peer`` is enabled (the default) then once the handshake 4578 is completed, the peer credentials will be verified, though this 4579 is a no-op for anonymous credentials. 4580 4581 The dir parameter tells QEMU where to find the credential files. 4582 For server endpoints, this directory may contain a file 4583 dh-params.pem providing diffie-hellman parameters to use for the 4584 TLS server. If the file is missing, QEMU will generate a set of 4585 DH parameters at startup. This is a computationally expensive 4586 operation that consumes random pool entropy, so it is 4587 recommended that a persistent set of parameters be generated 4588 upfront and saved. 4589 4590 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4591 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4592 can be used to provide TLS support on network backends. The 4593 ``id`` parameter is a unique ID which network backends will use 4594 to access the credentials. The ``endpoint`` is either ``server`` 4595 or ``client`` depending on whether the QEMU network backend that 4596 uses the credentials will be acting as a client or as a server. 4597 For clients only, ``username`` is the username which will be 4598 sent to the server. If omitted it defaults to "qemu". 4599 4600 The dir parameter tells QEMU where to find the keys file. It is 4601 called "dir/keys.psk" and contains "username:key" pairs. This 4602 file can most easily be created using the GnuTLS ``psktool`` 4603 program. 4604 4605 For server endpoints, dir may also contain a file dh-params.pem 4606 providing diffie-hellman parameters to use for the TLS server. 4607 If the file is missing, QEMU will generate a set of DH 4608 parameters at startup. This is a computationally expensive 4609 operation that consumes random pool entropy, so it is 4610 recommended that a persistent set of parameters be generated up 4611 front and saved. 4612 4613 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4614 Creates a TLS anonymous credentials object, which can be used to 4615 provide TLS support on network backends. The ``id`` parameter is 4616 a unique ID which network backends will use to access the 4617 credentials. The ``endpoint`` is either ``server`` or ``client`` 4618 depending on whether the QEMU network backend that uses the 4619 credentials will be acting as a client or as a server. If 4620 ``verify-peer`` is enabled (the default) then once the handshake 4621 is completed, the peer credentials will be verified. With x509 4622 certificates, this implies that the clients must be provided 4623 with valid client certificates too. 4624 4625 The dir parameter tells QEMU where to find the credential files. 4626 For server endpoints, this directory may contain a file 4627 dh-params.pem providing diffie-hellman parameters to use for the 4628 TLS server. If the file is missing, QEMU will generate a set of 4629 DH parameters at startup. This is a computationally expensive 4630 operation that consumes random pool entropy, so it is 4631 recommended that a persistent set of parameters be generated 4632 upfront and saved. 4633 4634 For x509 certificate credentials the directory will contain 4635 further files providing the x509 certificates. The certificates 4636 must be stored in PEM format, in filenames ca-cert.pem, 4637 ca-crl.pem (optional), server-cert.pem (only servers), 4638 server-key.pem (only servers), client-cert.pem (only clients), 4639 and client-key.pem (only clients). 4640 4641 For the server-key.pem and client-key.pem files which contain 4642 sensitive private keys, it is possible to use an encrypted 4643 version by providing the passwordid parameter. This provides the 4644 ID of a previously created ``secret`` object containing the 4645 password for decryption. 4646 4647 The priority parameter allows to override the global default 4648 priority used by gnutls. This can be useful if the system 4649 administrator needs to use a weaker set of crypto priorities for 4650 QEMU without potentially forcing the weakness onto all 4651 applications. Or conversely if one wants wants a stronger 4652 default for QEMU than for all other applications, they can do 4653 this through this parameter. Its format is a gnutls priority 4654 string as described at 4655 https://gnutls.org/manual/html_node/Priority-Strings.html. 4656 4657 ``-object tls-cipher-suites,id=id,priority=priority`` 4658 Creates a TLS cipher suites object, which can be used to control 4659 the TLS cipher/protocol algorithms that applications are permitted 4660 to use. 4661 4662 The ``id`` parameter is a unique ID which frontends will use to 4663 access the ordered list of permitted TLS cipher suites from the 4664 host. 4665 4666 The ``priority`` parameter allows to override the global default 4667 priority used by gnutls. This can be useful if the system 4668 administrator needs to use a weaker set of crypto priorities for 4669 QEMU without potentially forcing the weakness onto all 4670 applications. Or conversely if one wants wants a stronger 4671 default for QEMU than for all other applications, they can do 4672 this through this parameter. Its format is a gnutls priority 4673 string as described at 4674 https://gnutls.org/manual/html_node/Priority-Strings.html. 4675 4676 An example of use of this object is to control UEFI HTTPS Boot. 4677 The tls-cipher-suites object exposes the ordered list of permitted 4678 TLS cipher suites from the host side to the guest firmware, via 4679 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4680 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4681 guest-side TLS. 4682 4683 In the following example, the priority at which the host-side policy 4684 is retrieved is given by the ``priority`` property. 4685 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4686 refer to /etc/crypto-policies/back-ends/gnutls.config. 4687 4688 .. parsed-literal:: 4689 4690 # |qemu_system| \\ 4691 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4692 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4693 4694 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4695 Interval t can't be 0, this filter batches the packet delivery: 4696 all packets arriving in a given interval on netdev netdevid are 4697 delayed until the end of the interval. Interval is in 4698 microseconds. ``status`` is optional that indicate whether the 4699 netfilter is on (enabled) or off (disabled), the default status 4700 for netfilter will be 'on'. 4701 4702 queue all\|rx\|tx is an option that can be applied to any 4703 netfilter. 4704 4705 ``all``: the filter is attached both to the receive and the 4706 transmit queue of the netdev (default). 4707 4708 ``rx``: the filter is attached to the receive queue of the 4709 netdev, where it will receive packets sent to the netdev. 4710 4711 ``tx``: the filter is attached to the transmit queue of the 4712 netdev, where it will receive packets sent by the netdev. 4713 4714 position head\|tail\|id=<id> is an option to specify where the 4715 filter should be inserted in the filter list. It can be applied 4716 to any netfilter. 4717 4718 ``head``: the filter is inserted at the head of the filter list, 4719 before any existing filters. 4720 4721 ``tail``: the filter is inserted at the tail of the filter list, 4722 behind any existing filters (default). 4723 4724 ``id=<id>``: the filter is inserted before or behind the filter 4725 specified by <id>, see the insert option below. 4726 4727 insert behind\|before is an option to specify where to insert 4728 the new filter relative to the one specified with 4729 position=id=<id>. It can be applied to any netfilter. 4730 4731 ``before``: insert before the specified filter. 4732 4733 ``behind``: insert behind the specified filter (default). 4734 4735 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4736 filter-mirror on netdev netdevid,mirror net packet to 4737 chardevchardevid, if it has the vnet\_hdr\_support flag, 4738 filter-mirror will mirror packet with vnet\_hdr\_len. 4739 4740 ``-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]`` 4741 filter-redirector on netdev netdevid,redirect filter's net 4742 packet to chardev chardevid,and redirect indev's packet to 4743 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4744 will redirect packet with vnet\_hdr\_len. Create a 4745 filter-redirector we need to differ outdev id from indev id, id 4746 can not be the same. we can just use indev or outdev, but at 4747 least one of indev or outdev need to be specified. 4748 4749 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4750 Filter-rewriter is a part of COLO project.It will rewrite tcp 4751 packet to secondary from primary to keep secondary tcp 4752 connection,and rewrite tcp packet to primary from secondary make 4753 tcp packet can be handled by client.if it has the 4754 vnet\_hdr\_support flag, we can parse packet with vnet header. 4755 4756 usage: colo secondary: -object 4757 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4758 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4759 filter-rewriter,id=rew0,netdev=hn0,queue=all 4760 4761 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4762 Dump the network traffic on netdev dev to the file specified by 4763 filename. At most len bytes (64k by default) per packet are 4764 stored. The file format is libpcap, so it can be analyzed with 4765 tools such as tcpdump or Wireshark. 4766 4767 ``-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}]`` 4768 Colo-compare gets packet from primary\_in chardevid and 4769 secondary\_in, then compare whether the payload of primary packet 4770 and secondary packet are the same. If same, it will output 4771 primary packet to out\_dev, else it will notify COLO-framework to do 4772 checkpoint and send primary packet to out\_dev. In order to 4773 improve efficiency, we need to put the task of comparison in 4774 another iothread. If it has the vnet\_hdr\_support flag, 4775 colo compare will send/recv packet with vnet\_hdr\_len. 4776 The compare\_timeout=@var{ms} determines the maximum time of the 4777 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4778 is to set the period of scanning expired primary node network packets. 4779 The max\_queue\_size=@var{size} is to set the max compare queue 4780 size depend on user environment. 4781 If user want to use Xen COLO, need to add the notify\_dev to 4782 notify Xen colo-frame to do checkpoint. 4783 4784 COLO-compare must be used with the help of filter-mirror, 4785 filter-redirector and filter-rewriter. 4786 4787 :: 4788 4789 KVM COLO 4790 4791 primary: 4792 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4793 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4794 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4795 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4796 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4797 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4798 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4799 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4800 -object iothread,id=iothread1 4801 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4802 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4803 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4804 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4805 4806 secondary: 4807 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4808 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4809 -chardev socket,id=red0,host=3.3.3.3,port=9003 4810 -chardev socket,id=red1,host=3.3.3.3,port=9004 4811 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4812 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4813 4814 4815 Xen COLO 4816 4817 primary: 4818 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4819 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4820 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4821 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4822 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4823 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4824 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4825 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4826 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait 4827 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4828 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4829 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4830 -object iothread,id=iothread1 4831 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4832 4833 secondary: 4834 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4835 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4836 -chardev socket,id=red0,host=3.3.3.3,port=9003 4837 -chardev socket,id=red1,host=3.3.3.3,port=9004 4838 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4839 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4840 4841 If you want to know the detail of above command line, you can 4842 read the colo-compare git log. 4843 4844 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4845 Creates a cryptodev backend which executes crypto opreation from 4846 the QEMU cipher APIS. The id parameter is a unique ID that will 4847 be used to reference this cryptodev backend from the 4848 ``virtio-crypto`` device. The queues parameter is optional, 4849 which specify the queue number of cryptodev backend, the default 4850 of queues is 1. 4851 4852 .. parsed-literal:: 4853 4854 # |qemu_system| \\ 4855 [...] \\ 4856 -object cryptodev-backend-builtin,id=cryptodev0 \\ 4857 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4858 [...] 4859 4860 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4861 Creates a vhost-user cryptodev backend, backed by a chardev 4862 chardevid. The id parameter is a unique ID that will be used to 4863 reference this cryptodev backend from the ``virtio-crypto`` 4864 device. The chardev should be a unix domain socket backed one. 4865 The vhost-user uses a specifically defined protocol to pass 4866 vhost ioctl replacement messages to an application on the other 4867 end of the socket. The queues parameter is optional, which 4868 specify the queue number of cryptodev backend for multiqueue 4869 vhost-user, the default of queues is 1. 4870 4871 .. parsed-literal:: 4872 4873 # |qemu_system| \\ 4874 [...] \\ 4875 -chardev socket,id=chardev0,path=/path/to/socket \\ 4876 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 4877 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4878 [...] 4879 4880 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 4881 \ 4882 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 4883 Defines a secret to store a password, encryption key, or some 4884 other sensitive data. The sensitive data can either be passed 4885 directly via the data parameter, or indirectly via the file 4886 parameter. Using the data parameter is insecure unless the 4887 sensitive data is encrypted. 4888 4889 The sensitive data can be provided in raw format (the default), 4890 or base64. When encoded as JSON, the raw format only supports 4891 valid UTF-8 characters, so base64 is recommended for sending 4892 binary data. QEMU will convert from which ever format is 4893 provided to the format it needs internally. eg, an RBD password 4894 can be provided in raw format, even though it will be base64 4895 encoded when passed onto the RBD sever. 4896 4897 For added protection, it is possible to encrypt the data 4898 associated with a secret using the AES-256-CBC cipher. Use of 4899 encryption is indicated by providing the keyid and iv 4900 parameters. The keyid parameter provides the ID of a previously 4901 defined secret that contains the AES-256 decryption key. This 4902 key should be 32-bytes long and be base64 encoded. The iv 4903 parameter provides the random initialization vector used for 4904 encryption of this particular secret and should be a base64 4905 encrypted string of the 16-byte IV. 4906 4907 The simplest (insecure) usage is to provide the secret inline 4908 4909 .. parsed-literal:: 4910 4911 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 4912 4913 The simplest secure usage is to provide the secret via a file 4914 4915 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 4916 secret,id=sec0,file=mypasswd.txt,format=raw 4917 4918 For greater security, AES-256-CBC should be used. To illustrate 4919 usage, consider the openssl command line tool which can encrypt 4920 the data. Note that when encrypting, the plaintext must be 4921 padded to the cipher block size (32 bytes) using the standard 4922 PKCS#5/6 compatible padding algorithm. 4923 4924 First a master key needs to be created in base64 encoding: 4925 4926 :: 4927 4928 # openssl rand -base64 32 > key.b64 4929 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 4930 4931 Each secret to be encrypted needs to have a random 4932 initialization vector generated. These do not need to be kept 4933 secret 4934 4935 :: 4936 4937 # openssl rand -base64 16 > iv.b64 4938 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 4939 4940 The secret to be defined can now be encrypted, in this case 4941 we're telling openssl to base64 encode the result, but it could 4942 be left as raw bytes if desired. 4943 4944 :: 4945 4946 # SECRET=$(printf "letmein" | 4947 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 4948 4949 When launching QEMU, create a master secret pointing to 4950 ``key.b64`` and specify that to be used to decrypt the user 4951 password. Pass the contents of ``iv.b64`` to the second secret 4952 4953 .. parsed-literal:: 4954 4955 # |qemu_system| \\ 4956 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 4957 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 4958 data=$SECRET,iv=$(<iv.b64) 4959 4960 ``-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]`` 4961 Create a Secure Encrypted Virtualization (SEV) guest object, 4962 which can be used to provide the guest memory encryption support 4963 on AMD processors. 4964 4965 When memory encryption is enabled, one of the physical address 4966 bit (aka the C-bit) is utilized to mark if a memory page is 4967 protected. The ``cbitpos`` is used to provide the C-bit 4968 position. The C-bit position is Host family dependent hence user 4969 must provide this value. On EPYC, the value should be 47. 4970 4971 When memory encryption is enabled, we loose certain bits in 4972 physical address space. The ``reduced-phys-bits`` is used to 4973 provide the number of bits we loose in physical address space. 4974 Similar to C-bit, the value is Host family dependent. On EPYC, 4975 the value should be 5. 4976 4977 The ``sev-device`` provides the device file to use for 4978 communicating with the SEV firmware running inside AMD Secure 4979 Processor. The default device is '/dev/sev'. If hardware 4980 supports memory encryption then /dev/sev devices are created by 4981 CCP driver. 4982 4983 The ``policy`` provides the guest policy to be enforced by the 4984 SEV firmware and restrict what configuration and operational 4985 commands can be performed on this guest by the hypervisor. The 4986 policy should be provided by the guest owner and is bound to the 4987 guest and cannot be changed throughout the lifetime of the 4988 guest. The default is 0. 4989 4990 If guest ``policy`` allows sharing the key with another SEV 4991 guest then ``handle`` can be use to provide handle of the guest 4992 from which to share the key. 4993 4994 The ``dh-cert-file`` and ``session-file`` provides the guest 4995 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 4996 and session parameters are used for establishing a cryptographic 4997 session with the guest owner to negotiate keys used for 4998 attestation. The file must be encoded in base64. 4999 5000 e.g to launch a SEV guest 5001 5002 .. parsed-literal:: 5003 5004 # |qemu_system_x86| \\ 5005 ...... \\ 5006 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5007 -machine ...,memory-encryption=sev0 \\ 5008 ..... 5009 5010 ``-object authz-simple,id=id,identity=string`` 5011 Create an authorization object that will control access to 5012 network services. 5013 5014 The ``identity`` parameter is identifies the user and its format 5015 depends on the network service that authorization object is 5016 associated with. For authorizing based on TLS x509 certificates, 5017 the identity must be the x509 distinguished name. Note that care 5018 must be taken to escape any commas in the distinguished name. 5019 5020 An example authorization object to validate a x509 distinguished 5021 name would look like: 5022 5023 .. parsed-literal:: 5024 5025 # |qemu_system| \\ 5026 ... \\ 5027 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5028 ... 5029 5030 Note the use of quotes due to the x509 distinguished name 5031 containing whitespace, and escaping of ','. 5032 5033 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5034 Create an authorization object that will control access to 5035 network services. 5036 5037 The ``filename`` parameter is the fully qualified path to a file 5038 containing the access control list rules in JSON format. 5039 5040 An example set of rules that match against SASL usernames might 5041 look like: 5042 5043 :: 5044 5045 { 5046 "rules": [ 5047 { "match": "fred", "policy": "allow", "format": "exact" }, 5048 { "match": "bob", "policy": "allow", "format": "exact" }, 5049 { "match": "danb", "policy": "deny", "format": "glob" }, 5050 { "match": "dan*", "policy": "allow", "format": "exact" }, 5051 ], 5052 "policy": "deny" 5053 } 5054 5055 When checking access the object will iterate over all the rules 5056 and the first rule to match will have its ``policy`` value 5057 returned as the result. If no rules match, then the default 5058 ``policy`` value is returned. 5059 5060 The rules can either be an exact string match, or they can use 5061 the simple UNIX glob pattern matching to allow wildcards to be 5062 used. 5063 5064 If ``refresh`` is set to true the file will be monitored and 5065 automatically reloaded whenever its content changes. 5066 5067 As with the ``authz-simple`` object, the format of the identity 5068 strings being matched depends on the network service, but is 5069 usually a TLS x509 distinguished name, or a SASL username. 5070 5071 An example authorization object to validate a SASL username 5072 would look like: 5073 5074 .. parsed-literal:: 5075 5076 # |qemu_system| \\ 5077 ... \\ 5078 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5079 ... 5080 5081 ``-object authz-pam,id=id,service=string`` 5082 Create an authorization object that will control access to 5083 network services. 5084 5085 The ``service`` parameter provides the name of a PAM service to 5086 use for authorization. It requires that a file 5087 ``/etc/pam.d/service`` exist to provide the configuration for 5088 the ``account`` subsystem. 5089 5090 An example authorization object to validate a TLS x509 5091 distinguished name would look like: 5092 5093 .. parsed-literal:: 5094 5095 # |qemu_system| \\ 5096 ... \\ 5097 -object authz-pam,id=auth0,service=qemu-vnc \\ 5098 ... 5099 5100 There would then be a corresponding config file for PAM at 5101 ``/etc/pam.d/qemu-vnc`` that contains: 5102 5103 :: 5104 5105 account requisite pam_listfile.so item=user sense=allow \ 5106 file=/etc/qemu/vnc.allow 5107 5108 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5109 of x509 distingished names that are permitted access 5110 5111 :: 5112 5113 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5114 5115 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5116 Creates a dedicated event loop thread that devices can be 5117 assigned to. This is known as an IOThread. By default device 5118 emulation happens in vCPU threads or the main event loop thread. 5119 This can become a scalability bottleneck. IOThreads allow device 5120 emulation and I/O to run on other host CPUs. 5121 5122 The ``id`` parameter is a unique ID that will be used to 5123 reference this IOThread from ``-device ...,iothread=id``. 5124 Multiple devices can be assigned to an IOThread. Note that not 5125 all devices support an ``iothread`` parameter. 5126 5127 The ``query-iothreads`` QMP command lists IOThreads and reports 5128 their thread IDs so that the user can configure host CPU 5129 pinning/affinity. 5130 5131 IOThreads use an adaptive polling algorithm to reduce event loop 5132 latency. Instead of entering a blocking system call to monitor 5133 file descriptors and then pay the cost of being woken up when an 5134 event occurs, the polling algorithm spins waiting for events for 5135 a short time. The algorithm's default parameters are suitable 5136 for many cases but can be adjusted based on knowledge of the 5137 workload and/or host device latency. 5138 5139 The ``poll-max-ns`` parameter is the maximum number of 5140 nanoseconds to busy wait for events. Polling can be disabled by 5141 setting this value to 0. 5142 5143 The ``poll-grow`` parameter is the multiplier used to increase 5144 the polling time when the algorithm detects it is missing events 5145 due to not polling long enough. 5146 5147 The ``poll-shrink`` parameter is the divisor used to decrease 5148 the polling time when the algorithm detects it is spending too 5149 long polling without encountering events. 5150 5151 The polling parameters can be modified at run-time using the 5152 ``qom-set`` command (where ``iothread1`` is the IOThread's 5153 ``id``): 5154 5155 :: 5156 5157 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5158ERST 5159 5160 5161HXCOMM This is the last statement. Insert new options before this line! 5162
