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