1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST version and 3HXCOMM discarded from C version. 4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 5HXCOMM construct option structures, enums and help message for specified 6HXCOMM architectures. 7HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hax, hvf, nvmm, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n", 40 QEMU_ARCH_ALL) 41SRST 42``-machine [type=]name[,prop=value[,...]]`` 43 Select the emulated machine by name. Use ``-machine help`` to list 44 available machines. 45 46 For architectures which aim to support live migration compatibility 47 across releases, each release will introduce a new versioned machine 48 type. For example, the 2.8.0 release introduced machine types 49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 50 51 To allow live migration of guests from QEMU version 2.8.0, to QEMU 52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 54 skip multiple intermediate releases when upgrading, new releases of 55 QEMU will support machine types from many previous versions. 56 57 Supported machine properties are: 58 59 ``accel=accels1[:accels2[:...]]`` 60 This is used to enable an accelerator. Depending on the target 61 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 62 By default, tcg is used. If there is more than one accelerator 63 specified, the next one is used if the previous one fails to 64 initialize. 65 66 ``vmport=on|off|auto`` 67 Enables emulation of VMWare IO port, for vmmouse etc. auto says 68 to select the value based on accel. For accel=xen the default is 69 off otherwise the default is on. 70 71 ``dump-guest-core=on|off`` 72 Include guest memory in a core dump. The default is on. 73 74 ``mem-merge=on|off`` 75 Enables or disables memory merge support. This feature, when 76 supported by the host, de-duplicates identical memory pages 77 among VMs instances (enabled by default). 78 79 ``aes-key-wrap=on|off`` 80 Enables or disables AES key wrapping support on s390-ccw hosts. 81 This feature controls whether AES wrapping keys will be created 82 to allow execution of AES cryptographic functions. The default 83 is on. 84 85 ``dea-key-wrap=on|off`` 86 Enables or disables DEA key wrapping support on s390-ccw hosts. 87 This feature controls whether DEA wrapping keys will be created 88 to allow execution of DEA cryptographic functions. The default 89 is on. 90 91 ``nvdimm=on|off`` 92 Enables or disables NVDIMM support. The default is off. 93 94 ``memory-encryption=`` 95 Memory encryption object to use. The default is none. 96 97 ``hmat=on|off`` 98 Enables or disables ACPI Heterogeneous Memory Attribute Table 99 (HMAT) support. The default is off. 100 101 ``memory-backend='id'`` 102 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 103 Allows to use a memory backend as main RAM. 104 105 For example: 106 :: 107 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 108 -machine memory-backend=pc.ram 109 -m 512M 110 111 Migration compatibility note: 112 a) as backend id one shall use value of 'default-ram-id', advertised by 113 machine type (available via ``query-machines`` QMP command), if migration 114 to/from old QEMU (<5.0) is expected. 115 b) for machine types 4.0 and older, user shall 116 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 117 if migration to/from old QEMU (<5.0) is expected. 118 For example: 119 :: 120 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 121 -machine memory-backend=pc.ram 122 -m 512M 123ERST 124 125HXCOMM Deprecated by -machine 126DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL) 127 128DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 129 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 130SRST 131``-cpu model`` 132 Select CPU model (``-cpu help`` for list and additional feature 133 selection) 134ERST 135 136DEF("accel", HAS_ARG, QEMU_OPTION_accel, 137 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 138 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 139 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 140 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 141 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 142 " split-wx=on|off (enable TCG split w^x mapping)\n" 143 " tb-size=n (TCG translation block cache size)\n" 144 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 145 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 146SRST 147``-accel name[,prop=value[,...]]`` 148 This is used to enable an accelerator. Depending on the target 149 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 150 default, tcg is used. If there is more than one accelerator 151 specified, the next one is used if the previous one fails to 152 initialize. 153 154 ``igd-passthru=on|off`` 155 When Xen is in use, this option controls whether Intel 156 integrated graphics devices can be passed through to the guest 157 (default=off) 158 159 ``kernel-irqchip=on|off|split`` 160 Controls KVM in-kernel irqchip support. The default is full 161 acceleration of the interrupt controllers. On x86, split irqchip 162 reduces the kernel attack surface, at a performance cost for 163 non-MSI interrupts. Disabling the in-kernel irqchip completely 164 is not recommended except for debugging purposes. 165 166 ``kvm-shadow-mem=size`` 167 Defines the size of the KVM shadow MMU. 168 169 ``split-wx=on|off`` 170 Controls the use of split w^x mapping for the TCG code generation 171 buffer. Some operating systems require this to be enabled, and in 172 such a case this will default on. On other operating systems, this 173 will default off, but one may enable this for testing or debugging. 174 175 ``tb-size=n`` 176 Controls the size (in MiB) of the TCG translation block cache. 177 178 ``thread=single|multi`` 179 Controls number of TCG threads. When the TCG is multi-threaded 180 there will be one thread per vCPU therefore taking advantage of 181 additional host cores. The default is to enable multi-threading 182 where both the back-end and front-ends support it and no 183 incompatible TCG features have been enabled (e.g. 184 icount/replay). 185 186 ``dirty-ring-size=n`` 187 When the KVM accelerator is used, it controls the size of the per-vCPU 188 dirty page ring buffer (number of entries for each vCPU). It should 189 be a value that is power of two, and it should be 1024 or bigger (but 190 still less than the maximum value that the kernel supports). 4096 191 could be a good initial value if you have no idea which is the best. 192 Set this value to 0 to disable the feature. By default, this feature 193 is disabled (dirty-ring-size=0). When enabled, KVM will instead 194 record dirty pages in a bitmap. 195 196ERST 197 198DEF("smp", HAS_ARG, QEMU_OPTION_smp, 199 "-smp [[cpus=]n][,maxcpus=cpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]\n" 200 " set the number of CPUs to 'n' [default=1]\n" 201 " maxcpus= maximum number of total CPUs, including\n" 202 " offline CPUs for hotplug, etc\n" 203 " sockets= number of discrete sockets in the system\n" 204 " dies= number of CPU dies on one socket (for PC only)\n" 205 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 206 " threads= number of threads on one CPU core\n", 207 QEMU_ARCH_ALL) 208SRST 209``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]`` 210 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 211 the machine type board. On boards supporting CPU hotplug, the optional 212 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 213 added at runtime. If omitted the maximum number of CPUs will be 214 set to match the initial CPU count. Both parameters are subject to 215 an upper limit that is determined by the specific machine type chosen. 216 217 To control reporting of CPU topology information, the number of sockets, 218 dies per socket, cores per die, and threads per core can be specified. 219 The sum `` sockets * cores * dies * threads `` must be equal to the 220 maximum CPU count. CPU targets may only support a subset of the topology 221 parameters. Where a CPU target does not support use of a particular 222 topology parameter, its value should be assumed to be 1 for the purpose 223 of computing the CPU maximum count. 224 225 Either the initial CPU count, or at least one of the topology parameters 226 must be specified. Values for any omitted parameters will be computed 227 from those which are given. Historically preference was given to the 228 coarsest topology parameters when computing missing values (ie sockets 229 preferred over cores, which were preferred over threads), however, this 230 behaviour is considered liable to change. 231ERST 232 233DEF("numa", HAS_ARG, QEMU_OPTION_numa, 234 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 235 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 236 "-numa dist,src=source,dst=destination,val=distance\n" 237 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 238 "-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" 239 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 240 QEMU_ARCH_ALL) 241SRST 242``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 243 \ 244``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 245 \ 246``-numa dist,src=source,dst=destination,val=distance`` 247 \ 248``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 249 \ 250``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 251 \ 252``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 253 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 254 distance from a source node to a destination node. Set the ACPI 255 Heterogeneous Memory Attributes for the given nodes. 256 257 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 258 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 259 contiguous range of CPU indexes (or a single VCPU if lastcpu is 260 omitted). A non-contiguous set of VCPUs can be represented by 261 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 262 omitted on all nodes, VCPUs are automatically split between them. 263 264 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 265 NUMA node: 266 267 :: 268 269 -numa node,cpus=0-2,cpus=5 270 271 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 272 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 273 assign CPU objects to a node using topology layout properties of 274 CPU. The set of properties is machine specific, and depends on used 275 machine type/'\ ``smp``\ ' options. It could be queried with 276 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 277 property specifies node to which CPU object will be assigned, it's 278 required for node to be declared with '\ ``node``\ ' option before 279 it's used with '\ ``cpu``\ ' option. 280 281 For example: 282 283 :: 284 285 -M pc \ 286 -smp 1,sockets=2,maxcpus=2 \ 287 -numa node,nodeid=0 -numa node,nodeid=1 \ 288 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 289 290 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 291 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 292 a given memory backend device to a node. If '\ ``mem``\ ' and 293 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 294 295 296 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 297 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 298 use it. 299 300 '\ ``initiator``\ ' is an additional option that points to an 301 initiator NUMA node that has best performance (the lowest latency or 302 largest bandwidth) to this NUMA node. Note that this option can be 303 set only when the machine property 'hmat' is set to 'on'. 304 305 Following example creates a machine with 2 NUMA nodes, node 0 has 306 CPU. node 1 has only memory, and its initiator is node 0. Note that 307 because node 0 has CPU, by default the initiator of node 0 is itself 308 and must be itself. 309 310 :: 311 312 -machine hmat=on \ 313 -m 2G,slots=2,maxmem=4G \ 314 -object memory-backend-ram,size=1G,id=m0 \ 315 -object memory-backend-ram,size=1G,id=m1 \ 316 -numa node,nodeid=0,memdev=m0 \ 317 -numa node,nodeid=1,memdev=m1,initiator=0 \ 318 -smp 2,sockets=2,maxcpus=2 \ 319 -numa cpu,node-id=0,socket-id=0 \ 320 -numa cpu,node-id=0,socket-id=1 321 322 source and destination are NUMA node IDs. distance is the NUMA 323 distance from source to destination. The distance from a node to 324 itself is always 10. If any pair of nodes is given a distance, then 325 all pairs must be given distances. Although, when distances are only 326 given in one direction for each pair of nodes, then the distances in 327 the opposite directions are assumed to be the same. If, however, an 328 asymmetrical pair of distances is given for even one node pair, then 329 all node pairs must be provided distance values for both directions, 330 even when they are symmetrical. When a node is unreachable from 331 another node, set the pair's distance to 255. 332 333 Note that the -``numa`` option doesn't allocate any of the specified 334 resources, it just assigns existing resources to NUMA nodes. This 335 means that one still has to use the ``-m``, ``-smp`` options to 336 allocate RAM and VCPUs respectively. 337 338 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 339 Information between initiator and target NUMA nodes in ACPI 340 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 341 create memory requests, usually it has one or more processors. 342 Target NUMA node contains addressable memory. 343 344 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 345 the memory hierarchy of the target NUMA node: if hierarchy is 346 'memory', the structure represents the memory performance; if 347 hierarchy is 'first-level\|second-level\|third-level', this 348 structure represents aggregated performance of memory side caches 349 for each domain. type of 'data-type' is type of data represented by 350 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 351 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 352 the target memory; if 'hierarchy' is 353 'first-level\|second-level\|third-level', 'data-type' is 354 'access\|read\|write' hit latency or 'access\|read\|write' hit 355 bandwidth of the target memory side cache. 356 357 lat is latency value in nanoseconds. bw is bandwidth value, the 358 possible value and units are NUM[M\|G\|T], mean that the bandwidth 359 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 360 used suffix). Note that if latency or bandwidth value is 0, means 361 the corresponding latency or bandwidth information is not provided. 362 363 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 364 belongs. size is the size of memory side cache in bytes. level is 365 the cache level described in this structure, note that the cache 366 level 0 should not be used with '\ ``hmat-cache``\ ' option. 367 associativity is the cache associativity, the possible value is 368 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 369 is the write policy. line is the cache Line size in bytes. 370 371 For example, the following options describe 2 NUMA nodes. Node 0 has 372 2 cpus and a ram, node 1 has only a ram. The processors in node 0 373 access memory in node 0 with access-latency 5 nanoseconds, 374 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 375 memory in NUMA node 1 with access-latency 10 nanoseconds, 376 access-bandwidth is 100 MB/s. And for memory side cache information, 377 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 378 policy is write-back, the cache Line size is 8 bytes: 379 380 :: 381 382 -machine hmat=on \ 383 -m 2G \ 384 -object memory-backend-ram,size=1G,id=m0 \ 385 -object memory-backend-ram,size=1G,id=m1 \ 386 -smp 2 \ 387 -numa node,nodeid=0,memdev=m0 \ 388 -numa node,nodeid=1,memdev=m1,initiator=0 \ 389 -numa cpu,node-id=0,socket-id=0 \ 390 -numa cpu,node-id=0,socket-id=1 \ 391 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 392 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 393 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 394 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 395 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 396 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 397ERST 398 399DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 400 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 401 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 402SRST 403``-add-fd fd=fd,set=set[,opaque=opaque]`` 404 Add a file descriptor to an fd set. Valid options are: 405 406 ``fd=fd`` 407 This option defines the file descriptor of which a duplicate is 408 added to fd set. The file descriptor cannot be stdin, stdout, or 409 stderr. 410 411 ``set=set`` 412 This option defines the ID of the fd set to add the file 413 descriptor to. 414 415 ``opaque=opaque`` 416 This option defines a free-form string that can be used to 417 describe fd. 418 419 You can open an image using pre-opened file descriptors from an fd 420 set: 421 422 .. parsed-literal:: 423 424 |qemu_system| \\ 425 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 426 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 427 -drive file=/dev/fdset/2,index=0,media=disk 428ERST 429 430DEF("set", HAS_ARG, QEMU_OPTION_set, 431 "-set group.id.arg=value\n" 432 " set <arg> parameter for item <id> of type <group>\n" 433 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 434SRST 435``-set group.id.arg=value`` 436 Set parameter arg for item id of type group 437ERST 438 439DEF("global", HAS_ARG, QEMU_OPTION_global, 440 "-global driver.property=value\n" 441 "-global driver=driver,property=property,value=value\n" 442 " set a global default for a driver property\n", 443 QEMU_ARCH_ALL) 444SRST 445``-global driver.prop=value`` 446 \ 447``-global driver=driver,property=property,value=value`` 448 Set default value of driver's property prop to value, e.g.: 449 450 .. parsed-literal:: 451 452 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 453 454 In particular, you can use this to set driver properties for devices 455 which are created automatically by the machine model. To create a 456 device which is not created automatically and set properties on it, 457 use -``device``. 458 459 -global driver.prop=value is shorthand for -global 460 driver=driver,property=prop,value=value. The longhand syntax works 461 even when driver contains a dot. 462ERST 463 464DEF("boot", HAS_ARG, QEMU_OPTION_boot, 465 "-boot [order=drives][,once=drives][,menu=on|off]\n" 466 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 467 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 468 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 469 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 470 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 471 QEMU_ARCH_ALL) 472SRST 473``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 474 Specify boot order drives as a string of drive letters. Valid drive 475 letters depend on the target architecture. The x86 PC uses: a, b 476 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 477 (Etherboot from network adapter 1-4), hard disk boot is the default. 478 To apply a particular boot order only on the first startup, specify 479 it via ``once``. Note that the ``order`` or ``once`` parameter 480 should not be used together with the ``bootindex`` property of 481 devices, since the firmware implementations normally do not support 482 both at the same time. 483 484 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 485 as firmware/BIOS supports them. The default is non-interactive boot. 486 487 A splash picture could be passed to bios, enabling user to show it 488 as logo, when option splash=sp\_name is given and menu=on, If 489 firmware/BIOS supports them. Currently Seabios for X86 system 490 support it. limitation: The splash file could be a jpeg file or a 491 BMP file in 24 BPP format(true color). The resolution should be 492 supported by the SVGA mode, so the recommended is 320x240, 640x480, 493 800x640. 494 495 A timeout could be passed to bios, guest will pause for rb\_timeout 496 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 497 not reboot, qemu passes '-1' to bios by default. Currently Seabios 498 for X86 system support it. 499 500 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 501 it. This only effects when boot priority is changed by bootindex 502 options. The default is non-strict boot. 503 504 .. parsed-literal:: 505 506 # try to boot from network first, then from hard disk 507 |qemu_system_x86| -boot order=nc 508 # boot from CD-ROM first, switch back to default order after reboot 509 |qemu_system_x86| -boot once=d 510 # boot with a splash picture for 5 seconds. 511 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 512 513 Note: The legacy format '-boot drives' is still supported but its 514 use is discouraged as it may be removed from future versions. 515ERST 516 517DEF("m", HAS_ARG, QEMU_OPTION_m, 518 "-m [size=]megs[,slots=n,maxmem=size]\n" 519 " configure guest RAM\n" 520 " size: initial amount of guest memory\n" 521 " slots: number of hotplug slots (default: none)\n" 522 " maxmem: maximum amount of guest memory (default: none)\n" 523 "NOTE: Some architectures might enforce a specific granularity\n", 524 QEMU_ARCH_ALL) 525SRST 526``-m [size=]megs[,slots=n,maxmem=size]`` 527 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 528 Optionally, a suffix of "M" or "G" can be used to signify a value in 529 megabytes or gigabytes respectively. Optional pair slots, maxmem 530 could be used to set amount of hotpluggable memory slots and maximum 531 amount of memory. Note that maxmem must be aligned to the page size. 532 533 For example, the following command-line sets the guest startup RAM 534 size to 1GB, creates 3 slots to hotplug additional memory and sets 535 the maximum memory the guest can reach to 4GB: 536 537 .. parsed-literal:: 538 539 |qemu_system| -m 1G,slots=3,maxmem=4G 540 541 If slots and maxmem are not specified, memory hotplug won't be 542 enabled and the guest startup RAM will never increase. 543ERST 544 545DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 546 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 547SRST 548``-mem-path path`` 549 Allocate guest RAM from a temporarily created file in path. 550ERST 551 552DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 553 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 554 QEMU_ARCH_ALL) 555SRST 556``-mem-prealloc`` 557 Preallocate memory when using -mem-path. 558ERST 559 560DEF("k", HAS_ARG, QEMU_OPTION_k, 561 "-k language use keyboard layout (for example 'fr' for French)\n", 562 QEMU_ARCH_ALL) 563SRST 564``-k language`` 565 Use keyboard layout language (for example ``fr`` for French). This 566 option is only needed where it is not easy to get raw PC keycodes 567 (e.g. on Macs, with some X11 servers or with a VNC or curses 568 display). You don't normally need to use it on PC/Linux or 569 PC/Windows hosts. 570 571 The available layouts are: 572 573 :: 574 575 ar de-ch es fo fr-ca hu ja mk no pt-br sv 576 da en-gb et fr fr-ch is lt nl pl ru th 577 de en-us fi fr-be hr it lv nl-be pt sl tr 578 579 The default is ``en-us``. 580ERST 581 582 583HXCOMM Deprecated by -audiodev 584DEF("audio-help", 0, QEMU_OPTION_audio_help, 585 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 586 QEMU_ARCH_ALL) 587SRST 588``-audio-help`` 589 Will show the -audiodev equivalent of the currently specified 590 (deprecated) environment variables. 591ERST 592 593DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 594 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 595 " specifies the audio backend to use\n" 596 " id= identifier of the backend\n" 597 " timer-period= timer period in microseconds\n" 598 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 599 " in|out.fixed-settings= use fixed settings for host audio\n" 600 " in|out.frequency= frequency to use with fixed settings\n" 601 " in|out.channels= number of channels to use with fixed settings\n" 602 " in|out.format= sample format to use with fixed settings\n" 603 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 604 " in|out.voices= number of voices to use\n" 605 " in|out.buffer-length= length of buffer in microseconds\n" 606 "-audiodev none,id=id,[,prop[=value][,...]]\n" 607 " dummy driver that discards all output\n" 608#ifdef CONFIG_AUDIO_ALSA 609 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 610 " in|out.dev= name of the audio device to use\n" 611 " in|out.period-length= length of period in microseconds\n" 612 " in|out.try-poll= attempt to use poll mode\n" 613 " threshold= threshold (in microseconds) when playback starts\n" 614#endif 615#ifdef CONFIG_AUDIO_COREAUDIO 616 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 617 " in|out.buffer-count= number of buffers\n" 618#endif 619#ifdef CONFIG_AUDIO_DSOUND 620 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 621 " latency= add extra latency to playback in microseconds\n" 622#endif 623#ifdef CONFIG_AUDIO_OSS 624 "-audiodev oss,id=id[,prop[=value][,...]]\n" 625 " in|out.dev= path of the audio device to use\n" 626 " in|out.buffer-count= number of buffers\n" 627 " in|out.try-poll= attempt to use poll mode\n" 628 " try-mmap= try using memory mapped access\n" 629 " exclusive= open device in exclusive mode\n" 630 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 631#endif 632#ifdef CONFIG_AUDIO_PA 633 "-audiodev pa,id=id[,prop[=value][,...]]\n" 634 " server= PulseAudio server address\n" 635 " in|out.name= source/sink device name\n" 636 " in|out.latency= desired latency in microseconds\n" 637#endif 638#ifdef CONFIG_AUDIO_SDL 639 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 640 " in|out.buffer-count= number of buffers\n" 641#endif 642#ifdef CONFIG_SPICE 643 "-audiodev spice,id=id[,prop[=value][,...]]\n" 644#endif 645 "-audiodev wav,id=id[,prop[=value][,...]]\n" 646 " path= path of wav file to record\n", 647 QEMU_ARCH_ALL) 648SRST 649``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 650 Adds a new audio backend driver identified by id. There are global 651 and driver specific properties. Some values can be set differently 652 for input and output, they're marked with ``in|out.``. You can set 653 the input's property with ``in.prop`` and the output's property with 654 ``out.prop``. For example: 655 656 :: 657 658 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 659 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 660 661 NOTE: parameter validation is known to be incomplete, in many cases 662 specifying an invalid option causes QEMU to print an error message 663 and continue emulation without sound. 664 665 Valid global options are: 666 667 ``id=identifier`` 668 Identifies the audio backend. 669 670 ``timer-period=period`` 671 Sets the timer period used by the audio subsystem in 672 microseconds. Default is 10000 (10 ms). 673 674 ``in|out.mixing-engine=on|off`` 675 Use QEMU's mixing engine to mix all streams inside QEMU and 676 convert audio formats when not supported by the backend. When 677 off, fixed-settings must be off too. Note that disabling this 678 option means that the selected backend must support multiple 679 streams and the audio formats used by the virtual cards, 680 otherwise you'll get no sound. It's not recommended to disable 681 this option unless you want to use 5.1 or 7.1 audio, as mixing 682 engine only supports mono and stereo audio. Default is on. 683 684 ``in|out.fixed-settings=on|off`` 685 Use fixed settings for host audio. When off, it will change 686 based on how the guest opens the sound card. In this case you 687 must not specify frequency, channels or format. Default is on. 688 689 ``in|out.frequency=frequency`` 690 Specify the frequency to use when using fixed-settings. Default 691 is 44100Hz. 692 693 ``in|out.channels=channels`` 694 Specify the number of channels to use when using fixed-settings. 695 Default is 2 (stereo). 696 697 ``in|out.format=format`` 698 Specify the sample format to use when using fixed-settings. 699 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 700 ``u32``, ``f32``. Default is ``s16``. 701 702 ``in|out.voices=voices`` 703 Specify the number of voices to use. Default is 1. 704 705 ``in|out.buffer-length=usecs`` 706 Sets the size of the buffer in microseconds. 707 708``-audiodev none,id=id[,prop[=value][,...]]`` 709 Creates a dummy backend that discards all outputs. This backend has 710 no backend specific properties. 711 712``-audiodev alsa,id=id[,prop[=value][,...]]`` 713 Creates backend using the ALSA. This backend is only available on 714 Linux. 715 716 ALSA specific options are: 717 718 ``in|out.dev=device`` 719 Specify the ALSA device to use for input and/or output. Default 720 is ``default``. 721 722 ``in|out.period-length=usecs`` 723 Sets the period length in microseconds. 724 725 ``in|out.try-poll=on|off`` 726 Attempt to use poll mode with the device. Default is on. 727 728 ``threshold=threshold`` 729 Threshold (in microseconds) when playback starts. Default is 0. 730 731``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 732 Creates a backend using Apple's Core Audio. This backend is only 733 available on Mac OS and only supports playback. 734 735 Core Audio specific options are: 736 737 ``in|out.buffer-count=count`` 738 Sets the count of the buffers. 739 740``-audiodev dsound,id=id[,prop[=value][,...]]`` 741 Creates a backend using Microsoft's DirectSound. This backend is 742 only available on Windows and only supports playback. 743 744 DirectSound specific options are: 745 746 ``latency=usecs`` 747 Add extra usecs microseconds latency to playback. Default is 748 10000 (10 ms). 749 750``-audiodev oss,id=id[,prop[=value][,...]]`` 751 Creates a backend using OSS. This backend is available on most 752 Unix-like systems. 753 754 OSS specific options are: 755 756 ``in|out.dev=device`` 757 Specify the file name of the OSS device to use. Default is 758 ``/dev/dsp``. 759 760 ``in|out.buffer-count=count`` 761 Sets the count of the buffers. 762 763 ``in|out.try-poll=on|of`` 764 Attempt to use poll mode with the device. Default is on. 765 766 ``try-mmap=on|off`` 767 Try using memory mapped device access. Default is off. 768 769 ``exclusive=on|off`` 770 Open the device in exclusive mode (vmix won't work in this 771 case). Default is off. 772 773 ``dsp-policy=policy`` 774 Sets the timing policy (between 0 and 10, where smaller number 775 means smaller latency but higher CPU usage). Use -1 to use 776 buffer sizes specified by ``buffer`` and ``buffer-count``. This 777 option is ignored if you do not have OSS 4. Default is 5. 778 779``-audiodev pa,id=id[,prop[=value][,...]]`` 780 Creates a backend using PulseAudio. This backend is available on 781 most systems. 782 783 PulseAudio specific options are: 784 785 ``server=server`` 786 Sets the PulseAudio server to connect to. 787 788 ``in|out.name=sink`` 789 Use the specified source/sink for recording/playback. 790 791 ``in|out.latency=usecs`` 792 Desired latency in microseconds. The PulseAudio server will try 793 to honor this value but actual latencies may be lower or higher. 794 795``-audiodev sdl,id=id[,prop[=value][,...]]`` 796 Creates a backend using SDL. This backend is available on most 797 systems, but you should use your platform's native backend if 798 possible. 799 800 SDL specific options are: 801 802 ``in|out.buffer-count=count`` 803 Sets the count of the buffers. 804 805``-audiodev spice,id=id[,prop[=value][,...]]`` 806 Creates a backend that sends audio through SPICE. This backend 807 requires ``-spice`` and automatically selected in that case, so 808 usually you can ignore this option. This backend has no backend 809 specific properties. 810 811``-audiodev wav,id=id[,prop[=value][,...]]`` 812 Creates a backend that writes audio to a WAV file. 813 814 Backend specific options are: 815 816 ``path=path`` 817 Write recorded audio into the specified file. Default is 818 ``qemu.wav``. 819ERST 820 821DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 822 "-soundhw c1,... enable audio support\n" 823 " and only specified sound cards (comma separated list)\n" 824 " use '-soundhw help' to get the list of supported cards\n" 825 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 826SRST 827``-soundhw card1[,card2,...] or -soundhw all`` 828 Enable audio and selected sound hardware. Use 'help' to print all 829 available sound hardware. For example: 830 831 .. parsed-literal:: 832 833 |qemu_system_x86| -soundhw sb16,adlib disk.img 834 |qemu_system_x86| -soundhw es1370 disk.img 835 |qemu_system_x86| -soundhw ac97 disk.img 836 |qemu_system_x86| -soundhw hda disk.img 837 |qemu_system_x86| -soundhw all disk.img 838 |qemu_system_x86| -soundhw help 839 840 Note that Linux's i810\_audio OSS kernel (for AC97) module might 841 require manually specifying clocking. 842 843 :: 844 845 modprobe i810_audio clocking=48000 846ERST 847 848DEF("device", HAS_ARG, QEMU_OPTION_device, 849 "-device driver[,prop[=value][,...]]\n" 850 " add device (based on driver)\n" 851 " prop=value,... sets driver properties\n" 852 " use '-device help' to print all possible drivers\n" 853 " use '-device driver,help' to print all possible properties\n", 854 QEMU_ARCH_ALL) 855SRST 856``-device driver[,prop[=value][,...]]`` 857 Add device driver. prop=value sets driver properties. Valid 858 properties depend on the driver. To get help on possible drivers and 859 properties, use ``-device help`` and ``-device driver,help``. 860 861 Some drivers are: 862 863``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 864 Add an IPMI BMC. This is a simulation of a hardware management 865 interface processor that normally sits on a system. It provides a 866 watchdog and the ability to reset and power control the system. You 867 need to connect this to an IPMI interface to make it useful 868 869 The IPMI slave address to use for the BMC. The default is 0x20. This 870 address is the BMC's address on the I2C network of management 871 controllers. If you don't know what this means, it is safe to ignore 872 it. 873 874 ``id=id`` 875 The BMC id for interfaces to use this device. 876 877 ``slave_addr=val`` 878 Define slave address to use for the BMC. The default is 0x20. 879 880 ``sdrfile=file`` 881 file containing raw Sensor Data Records (SDR) data. The default 882 is none. 883 884 ``fruareasize=val`` 885 size of a Field Replaceable Unit (FRU) area. The default is 886 1024. 887 888 ``frudatafile=file`` 889 file containing raw Field Replaceable Unit (FRU) inventory data. 890 The default is none. 891 892 ``guid=uuid`` 893 value for the GUID for the BMC, in standard UUID format. If this 894 is set, get "Get GUID" command to the BMC will return it. 895 Otherwise "Get GUID" will return an error. 896 897``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 898 Add a connection to an external IPMI BMC simulator. Instead of 899 locally emulating the BMC like the above item, instead connect to an 900 external entity that provides the IPMI services. 901 902 A connection is made to an external BMC simulator. If you do this, 903 it is strongly recommended that you use the "reconnect=" chardev 904 option to reconnect to the simulator if the connection is lost. Note 905 that if this is not used carefully, it can be a security issue, as 906 the interface has the ability to send resets, NMIs, and power off 907 the VM. It's best if QEMU makes a connection to an external 908 simulator running on a secure port on localhost, so neither the 909 simulator nor QEMU is exposed to any outside network. 910 911 See the "lanserv/README.vm" file in the OpenIPMI library for more 912 details on the external interface. 913 914``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 915 Add a KCS IPMI interafce on the ISA bus. This also adds a 916 corresponding ACPI and SMBIOS entries, if appropriate. 917 918 ``bmc=id`` 919 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 920 above. 921 922 ``ioport=val`` 923 Define the I/O address of the interface. The default is 0xca0 924 for KCS. 925 926 ``irq=val`` 927 Define the interrupt to use. The default is 5. To disable 928 interrupts, set this to 0. 929 930``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 931 Like the KCS interface, but defines a BT interface. The default port 932 is 0xe4 and the default interrupt is 5. 933 934``-device pci-ipmi-kcs,bmc=id`` 935 Add a KCS IPMI interafce on the PCI bus. 936 937 ``bmc=id`` 938 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 939 940``-device pci-ipmi-bt,bmc=id`` 941 Like the KCS interface, but defines a BT interface on the PCI bus. 942ERST 943 944DEF("name", HAS_ARG, QEMU_OPTION_name, 945 "-name string1[,process=string2][,debug-threads=on|off]\n" 946 " set the name of the guest\n" 947 " string1 sets the window title and string2 the process name\n" 948 " When debug-threads is enabled, individual threads are given a separate name\n" 949 " NOTE: The thread names are for debugging and not a stable API.\n", 950 QEMU_ARCH_ALL) 951SRST 952``-name name`` 953 Sets the name of the guest. This name will be displayed in the SDL 954 window caption. The name will also be used for the VNC server. Also 955 optionally set the top visible process name in Linux. Naming of 956 individual threads can also be enabled on Linux to aid debugging. 957ERST 958 959DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 960 "-uuid %08x-%04x-%04x-%04x-%012x\n" 961 " specify machine UUID\n", QEMU_ARCH_ALL) 962SRST 963``-uuid uuid`` 964 Set system UUID. 965ERST 966 967DEFHEADING() 968 969DEFHEADING(Block device options:) 970 971DEF("fda", HAS_ARG, QEMU_OPTION_fda, 972 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 973DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 974SRST 975``-fda file`` 976 \ 977``-fdb file`` 978 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 979 the System Emulation Users Guide). 980ERST 981 982DEF("hda", HAS_ARG, QEMU_OPTION_hda, 983 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 984DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 985DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 986 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 987DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 988SRST 989``-hda file`` 990 \ 991``-hdb file`` 992 \ 993``-hdc file`` 994 \ 995``-hdd file`` 996 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 997 chapter in the System Emulation Users Guide). 998ERST 999 1000DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1001 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1002 QEMU_ARCH_ALL) 1003SRST 1004``-cdrom file`` 1005 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1006 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1007 as filename. 1008ERST 1009 1010DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1011 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1012 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1013 " [,read-only=on|off][,auto-read-only=on|off]\n" 1014 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1015 " [,driver specific parameters...]\n" 1016 " configure a block backend\n", QEMU_ARCH_ALL) 1017SRST 1018``-blockdev option[,option[,option[,...]]]`` 1019 Define a new block driver node. Some of the options apply to all 1020 block drivers, other options are only accepted for a specific block 1021 driver. See below for a list of generic options and options for the 1022 most common block drivers. 1023 1024 Options that expect a reference to another node (e.g. ``file``) can 1025 be given in two ways. Either you specify the node name of an already 1026 existing node (file=node-name), or you define a new node inline, 1027 adding options for the referenced node after a dot 1028 (file.filename=path,file.aio=native). 1029 1030 A block driver node created with ``-blockdev`` can be used for a 1031 guest device by specifying its node name for the ``drive`` property 1032 in a ``-device`` argument that defines a block device. 1033 1034 ``Valid options for any block driver node:`` 1035 ``driver`` 1036 Specifies the block driver to use for the given node. 1037 1038 ``node-name`` 1039 This defines the name of the block driver node by which it 1040 will be referenced later. The name must be unique, i.e. it 1041 must not match the name of a different block driver node, or 1042 (if you use ``-drive`` as well) the ID of a drive. 1043 1044 If no node name is specified, it is automatically generated. 1045 The generated node name is not intended to be predictable 1046 and changes between QEMU invocations. For the top level, an 1047 explicit node name must be specified. 1048 1049 ``read-only`` 1050 Open the node read-only. Guest write attempts will fail. 1051 1052 Note that some block drivers support only read-only access, 1053 either generally or in certain configurations. In this case, 1054 the default value ``read-only=off`` does not work and the 1055 option must be specified explicitly. 1056 1057 ``auto-read-only`` 1058 If ``auto-read-only=on`` is set, QEMU may fall back to 1059 read-only usage even when ``read-only=off`` is requested, or 1060 even switch between modes as needed, e.g. depending on 1061 whether the image file is writable or whether a writing user 1062 is attached to the node. 1063 1064 ``force-share`` 1065 Override the image locking system of QEMU by forcing the 1066 node to utilize weaker shared access for permissions where 1067 it would normally request exclusive access. When there is 1068 the potential for multiple instances to have the same file 1069 open (whether this invocation of QEMU is the first or the 1070 second instance), both instances must permit shared access 1071 for the second instance to succeed at opening the file. 1072 1073 Enabling ``force-share=on`` requires ``read-only=on``. 1074 1075 ``cache.direct`` 1076 The host page cache can be avoided with ``cache.direct=on``. 1077 This will attempt to do disk IO directly to the guest's 1078 memory. QEMU may still perform an internal copy of the data. 1079 1080 ``cache.no-flush`` 1081 In case you don't care about data integrity over host 1082 failures, you can use ``cache.no-flush=on``. This option 1083 tells QEMU that it never needs to write any data to the disk 1084 but can instead keep things in cache. If anything goes 1085 wrong, like your host losing power, the disk storage getting 1086 disconnected accidentally, etc. your image will most 1087 probably be rendered unusable. 1088 1089 ``discard=discard`` 1090 discard is one of "ignore" (or "off") or "unmap" (or "on") 1091 and controls whether ``discard`` (also known as ``trim`` or 1092 ``unmap``) requests are ignored or passed to the filesystem. 1093 Some machine types may not support discard requests. 1094 1095 ``detect-zeroes=detect-zeroes`` 1096 detect-zeroes is "off", "on" or "unmap" and enables the 1097 automatic conversion of plain zero writes by the OS to 1098 driver specific optimized zero write commands. You may even 1099 choose "unmap" if discard is set to "unmap" to allow a zero 1100 write to be converted to an ``unmap`` operation. 1101 1102 ``Driver-specific options for file`` 1103 This is the protocol-level block driver for accessing regular 1104 files. 1105 1106 ``filename`` 1107 The path to the image file in the local filesystem 1108 1109 ``aio`` 1110 Specifies the AIO backend (threads/native/io_uring, 1111 default: threads) 1112 1113 ``locking`` 1114 Specifies whether the image file is protected with Linux OFD 1115 / POSIX locks. The default is to use the Linux Open File 1116 Descriptor API if available, otherwise no lock is applied. 1117 (auto/on/off, default: auto) 1118 1119 Example: 1120 1121 :: 1122 1123 -blockdev driver=file,node-name=disk,filename=disk.img 1124 1125 ``Driver-specific options for raw`` 1126 This is the image format block driver for raw images. It is 1127 usually stacked on top of a protocol level block driver such as 1128 ``file``. 1129 1130 ``file`` 1131 Reference to or definition of the data source block driver 1132 node (e.g. a ``file`` driver node) 1133 1134 Example 1: 1135 1136 :: 1137 1138 -blockdev driver=file,node-name=disk_file,filename=disk.img 1139 -blockdev driver=raw,node-name=disk,file=disk_file 1140 1141 Example 2: 1142 1143 :: 1144 1145 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1146 1147 ``Driver-specific options for qcow2`` 1148 This is the image format block driver for qcow2 images. It is 1149 usually stacked on top of a protocol level block driver such as 1150 ``file``. 1151 1152 ``file`` 1153 Reference to or definition of the data source block driver 1154 node (e.g. a ``file`` driver node) 1155 1156 ``backing`` 1157 Reference to or definition of the backing file block device 1158 (default is taken from the image file). It is allowed to 1159 pass ``null`` here in order to disable the default backing 1160 file. 1161 1162 ``lazy-refcounts`` 1163 Whether to enable the lazy refcounts feature (on/off; 1164 default is taken from the image file) 1165 1166 ``cache-size`` 1167 The maximum total size of the L2 table and refcount block 1168 caches in bytes (default: the sum of l2-cache-size and 1169 refcount-cache-size) 1170 1171 ``l2-cache-size`` 1172 The maximum size of the L2 table cache in bytes (default: if 1173 cache-size is not specified - 32M on Linux platforms, and 8M 1174 on non-Linux platforms; otherwise, as large as possible 1175 within the cache-size, while permitting the requested or the 1176 minimal refcount cache size) 1177 1178 ``refcount-cache-size`` 1179 The maximum size of the refcount block cache in bytes 1180 (default: 4 times the cluster size; or if cache-size is 1181 specified, the part of it which is not used for the L2 1182 cache) 1183 1184 ``cache-clean-interval`` 1185 Clean unused entries in the L2 and refcount caches. The 1186 interval is in seconds. The default value is 600 on 1187 supporting platforms, and 0 on other platforms. Setting it 1188 to 0 disables this feature. 1189 1190 ``pass-discard-request`` 1191 Whether discard requests to the qcow2 device should be 1192 forwarded to the data source (on/off; default: on if 1193 discard=unmap is specified, off otherwise) 1194 1195 ``pass-discard-snapshot`` 1196 Whether discard requests for the data source should be 1197 issued when a snapshot operation (e.g. deleting a snapshot) 1198 frees clusters in the qcow2 file (on/off; default: on) 1199 1200 ``pass-discard-other`` 1201 Whether discard requests for the data source should be 1202 issued on other occasions where a cluster gets freed 1203 (on/off; default: off) 1204 1205 ``overlap-check`` 1206 Which overlap checks to perform for writes to the image 1207 (none/constant/cached/all; default: cached). For details or 1208 finer granularity control refer to the QAPI documentation of 1209 ``blockdev-add``. 1210 1211 Example 1: 1212 1213 :: 1214 1215 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1216 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1217 1218 Example 2: 1219 1220 :: 1221 1222 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1223 1224 ``Driver-specific options for other drivers`` 1225 Please refer to the QAPI documentation of the ``blockdev-add`` 1226 QMP command. 1227ERST 1228 1229DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1230 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1231 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1232 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1233 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1234 " [,aio=threads|native|io_uring]\n" 1235 " [,readonly=on|off][,copy-on-read=on|off]\n" 1236 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1237 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1238 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1239 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1240 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1241 " [[,iops_size=is]]\n" 1242 " [[,group=g]]\n" 1243 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1244SRST 1245``-drive option[,option[,option[,...]]]`` 1246 Define a new drive. This includes creating a block driver node (the 1247 backend) as well as a guest device, and is mostly a shortcut for 1248 defining the corresponding ``-blockdev`` and ``-device`` options. 1249 1250 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1251 In addition, it knows the following options: 1252 1253 ``file=file`` 1254 This option defines which disk image (see the :ref:`disk images` 1255 chapter in the System Emulation Users Guide) to use with this drive. 1256 If the filename contains comma, you must double it (for instance, 1257 "file=my,,file" to use file "my,file"). 1258 1259 Special files such as iSCSI devices can be specified using 1260 protocol specific URLs. See the section for "Device URL Syntax" 1261 for more information. 1262 1263 ``if=interface`` 1264 This option defines on which type on interface the drive is 1265 connected. Available types are: ide, scsi, sd, mtd, floppy, 1266 pflash, virtio, none. 1267 1268 ``bus=bus,unit=unit`` 1269 These options define where is connected the drive by defining 1270 the bus number and the unit id. 1271 1272 ``index=index`` 1273 This option defines where is connected the drive by using an 1274 index in the list of available connectors of a given interface 1275 type. 1276 1277 ``media=media`` 1278 This option defines the type of the media: disk or cdrom. 1279 1280 ``snapshot=snapshot`` 1281 snapshot is "on" or "off" and controls snapshot mode for the 1282 given drive (see ``-snapshot``). 1283 1284 ``cache=cache`` 1285 cache is "none", "writeback", "unsafe", "directsync" or 1286 "writethrough" and controls how the host cache is used to access 1287 block data. This is a shortcut that sets the ``cache.direct`` 1288 and ``cache.no-flush`` options (as in ``-blockdev``), and 1289 additionally ``cache.writeback``, which provides a default for 1290 the ``write-cache`` option of block guest devices (as in 1291 ``-device``). The modes correspond to the following settings: 1292 1293 ============= =============== ============ ============== 1294 \ cache.writeback cache.direct cache.no-flush 1295 ============= =============== ============ ============== 1296 writeback on off off 1297 none on on off 1298 writethrough off off off 1299 directsync off on off 1300 unsafe on off on 1301 ============= =============== ============ ============== 1302 1303 The default mode is ``cache=writeback``. 1304 1305 ``aio=aio`` 1306 aio is "threads", "native", or "io_uring" and selects between pthread 1307 based disk I/O, native Linux AIO, or Linux io_uring API. 1308 1309 ``format=format`` 1310 Specify which disk format will be used rather than detecting the 1311 format. Can be used to specify format=raw to avoid interpreting 1312 an untrusted format header. 1313 1314 ``werror=action,rerror=action`` 1315 Specify which action to take on write and read errors. Valid 1316 actions are: "ignore" (ignore the error and try to continue), 1317 "stop" (pause QEMU), "report" (report the error to the guest), 1318 "enospc" (pause QEMU only if the host disk is full; report the 1319 error to the guest otherwise). The default setting is 1320 ``werror=enospc`` and ``rerror=report``. 1321 1322 ``copy-on-read=copy-on-read`` 1323 copy-on-read is "on" or "off" and enables whether to copy read 1324 backing file sectors into the image file. 1325 1326 ``bps=b,bps_rd=r,bps_wr=w`` 1327 Specify bandwidth throttling limits in bytes per second, either 1328 for all request types or for reads or writes only. Small values 1329 can lead to timeouts or hangs inside the guest. A safe minimum 1330 for disks is 2 MB/s. 1331 1332 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1333 Specify bursts in bytes per second, either for all request types 1334 or for reads or writes only. Bursts allow the guest I/O to spike 1335 above the limit temporarily. 1336 1337 ``iops=i,iops_rd=r,iops_wr=w`` 1338 Specify request rate limits in requests per second, either for 1339 all request types or for reads or writes only. 1340 1341 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1342 Specify bursts in requests per second, either for all request 1343 types or for reads or writes only. Bursts allow the guest I/O to 1344 spike above the limit temporarily. 1345 1346 ``iops_size=is`` 1347 Let every is bytes of a request count as a new request for iops 1348 throttling purposes. Use this option to prevent guests from 1349 circumventing iops limits by sending fewer but larger requests. 1350 1351 ``group=g`` 1352 Join a throttling quota group with given name g. All drives that 1353 are members of the same group are accounted for together. Use 1354 this option to prevent guests from circumventing throttling 1355 limits by using many small disks instead of a single larger 1356 disk. 1357 1358 By default, the ``cache.writeback=on`` mode is used. It will report 1359 data writes as completed as soon as the data is present in the host 1360 page cache. This is safe as long as your guest OS makes sure to 1361 correctly flush disk caches where needed. If your guest OS does not 1362 handle volatile disk write caches correctly and your host crashes or 1363 loses power, then the guest may experience data corruption. 1364 1365 For such guests, you should consider using ``cache.writeback=off``. 1366 This means that the host page cache will be used to read and write 1367 data, but write notification will be sent to the guest only after 1368 QEMU has made sure to flush each write to the disk. Be aware that 1369 this has a major impact on performance. 1370 1371 When using the ``-snapshot`` option, unsafe caching is always used. 1372 1373 Copy-on-read avoids accessing the same backing file sectors 1374 repeatedly and is useful when the backing file is over a slow 1375 network. By default copy-on-read is off. 1376 1377 Instead of ``-cdrom`` you can use: 1378 1379 .. parsed-literal:: 1380 1381 |qemu_system| -drive file=file,index=2,media=cdrom 1382 1383 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1384 1385 .. parsed-literal:: 1386 1387 |qemu_system| -drive file=file,index=0,media=disk 1388 |qemu_system| -drive file=file,index=1,media=disk 1389 |qemu_system| -drive file=file,index=2,media=disk 1390 |qemu_system| -drive file=file,index=3,media=disk 1391 1392 You can open an image using pre-opened file descriptors from an fd 1393 set: 1394 1395 .. parsed-literal:: 1396 1397 |qemu_system| \\ 1398 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1399 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1400 -drive file=/dev/fdset/2,index=0,media=disk 1401 1402 You can connect a CDROM to the slave of ide0: 1403 1404 .. parsed-literal:: 1405 1406 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1407 1408 If you don't specify the "file=" argument, you define an empty 1409 drive: 1410 1411 .. parsed-literal:: 1412 1413 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1414 1415 Instead of ``-fda``, ``-fdb``, you can use: 1416 1417 .. parsed-literal:: 1418 1419 |qemu_system_x86| -drive file=file,index=0,if=floppy 1420 |qemu_system_x86| -drive file=file,index=1,if=floppy 1421 1422 By default, interface is "ide" and index is automatically 1423 incremented: 1424 1425 .. parsed-literal:: 1426 1427 |qemu_system_x86| -drive file=a -drive file=b" 1428 1429 is interpreted like: 1430 1431 .. parsed-literal:: 1432 1433 |qemu_system_x86| -hda a -hdb b 1434ERST 1435 1436DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1437 "-mtdblock file use 'file' as on-board Flash memory image\n", 1438 QEMU_ARCH_ALL) 1439SRST 1440``-mtdblock file`` 1441 Use file as on-board Flash memory image. 1442ERST 1443 1444DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1445 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1446SRST 1447``-sd file`` 1448 Use file as SecureDigital card image. 1449ERST 1450 1451DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1452 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1453SRST 1454``-pflash file`` 1455 Use file as a parallel flash image. 1456ERST 1457 1458DEF("snapshot", 0, QEMU_OPTION_snapshot, 1459 "-snapshot write to temporary files instead of disk image files\n", 1460 QEMU_ARCH_ALL) 1461SRST 1462``-snapshot`` 1463 Write to temporary files instead of disk image files. In this case, 1464 the raw disk image you use is not written back. You can however 1465 force the write back by pressing C-a s (see the :ref:`disk images` 1466 chapter in the System Emulation Users Guide). 1467ERST 1468 1469DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1470 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1471 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1472 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1473 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1474 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1475 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1476 " [[,throttling.iops-size=is]]\n" 1477 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1478 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1479 "-fsdev synth,id=id\n", 1480 QEMU_ARCH_ALL) 1481 1482SRST 1483``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1484 \ 1485``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1486 \ 1487``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1488 \ 1489``-fsdev synth,id=id[,readonly=on]`` 1490 Define a new file system device. Valid options are: 1491 1492 ``local`` 1493 Accesses to the filesystem are done by QEMU. 1494 1495 ``proxy`` 1496 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1497 1498 ``synth`` 1499 Synthetic filesystem, only used by QTests. 1500 1501 ``id=id`` 1502 Specifies identifier for this device. 1503 1504 ``path=path`` 1505 Specifies the export path for the file system device. Files 1506 under this path will be available to the 9p client on the guest. 1507 1508 ``security_model=security_model`` 1509 Specifies the security model to be used for this export path. 1510 Supported security models are "passthrough", "mapped-xattr", 1511 "mapped-file" and "none". In "passthrough" security model, files 1512 are stored using the same credentials as they are created on the 1513 guest. This requires QEMU to run as root. In "mapped-xattr" 1514 security model, some of the file attributes like uid, gid, mode 1515 bits and link target are stored as file attributes. For 1516 "mapped-file" these attributes are stored in the hidden 1517 .virtfs\_metadata directory. Directories exported by this 1518 security model cannot interact with other unix tools. "none" 1519 security model is same as passthrough except the sever won't 1520 report failures if it fails to set file attributes like 1521 ownership. Security model is mandatory only for local fsdriver. 1522 Other fsdrivers (like proxy) don't take security model as a 1523 parameter. 1524 1525 ``writeout=writeout`` 1526 This is an optional argument. The only supported value is 1527 "immediate". This means that host page cache will be used to 1528 read and write data but write notification will be sent to the 1529 guest only when the data has been reported as written by the 1530 storage subsystem. 1531 1532 ``readonly=on`` 1533 Enables exporting 9p share as a readonly mount for guests. By 1534 default read-write access is given. 1535 1536 ``socket=socket`` 1537 Enables proxy filesystem driver to use passed socket file for 1538 communicating with virtfs-proxy-helper(1). 1539 1540 ``sock_fd=sock_fd`` 1541 Enables proxy filesystem driver to use passed socket descriptor 1542 for communicating with virtfs-proxy-helper(1). Usually a helper 1543 like libvirt will create socketpair and pass one of the fds as 1544 sock\_fd. 1545 1546 ``fmode=fmode`` 1547 Specifies the default mode for newly created files on the host. 1548 Works only with security models "mapped-xattr" and 1549 "mapped-file". 1550 1551 ``dmode=dmode`` 1552 Specifies the default mode for newly created directories on the 1553 host. Works only with security models "mapped-xattr" and 1554 "mapped-file". 1555 1556 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1557 Specify bandwidth throttling limits in bytes per second, either 1558 for all request types or for reads or writes only. 1559 1560 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1561 Specify bursts in bytes per second, either for all request types 1562 or for reads or writes only. Bursts allow the guest I/O to spike 1563 above the limit temporarily. 1564 1565 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1566 Specify request rate limits in requests per second, either for 1567 all request types or for reads or writes only. 1568 1569 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1570 Specify bursts in requests per second, either for all request 1571 types or for reads or writes only. Bursts allow the guest I/O to 1572 spike above the limit temporarily. 1573 1574 ``throttling.iops-size=is`` 1575 Let every is bytes of a request count as a new request for iops 1576 throttling purposes. 1577 1578 -fsdev option is used along with -device driver "virtio-9p-...". 1579 1580``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1581 Options for virtio-9p-... driver are: 1582 1583 ``type`` 1584 Specifies the variant to be used. Supported values are "pci", 1585 "ccw" or "device", depending on the machine type. 1586 1587 ``fsdev=id`` 1588 Specifies the id value specified along with -fsdev option. 1589 1590 ``mount_tag=mount_tag`` 1591 Specifies the tag name to be used by the guest to mount this 1592 export point. 1593ERST 1594 1595DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1596 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1597 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1598 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1599 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1600 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1601 QEMU_ARCH_ALL) 1602 1603SRST 1604``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1605 \ 1606``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1607 \ 1608``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1609 \ 1610``-virtfs synth,mount_tag=mount_tag`` 1611 Define a new virtual filesystem device and expose it to the guest using 1612 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1613 directory on host is made directly accessible by guest as a pass-through 1614 file system by using the 9P network protocol for communication between 1615 host and guests, if desired even accessible, shared by several guests 1616 simultaniously. 1617 1618 Note that ``-virtfs`` is actually just a convenience shortcut for its 1619 generalized form ``-fsdev -device virtio-9p-pci``. 1620 1621 The general form of pass-through file system options are: 1622 1623 ``local`` 1624 Accesses to the filesystem are done by QEMU. 1625 1626 ``proxy`` 1627 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1628 1629 ``synth`` 1630 Synthetic filesystem, only used by QTests. 1631 1632 ``id=id`` 1633 Specifies identifier for the filesystem device 1634 1635 ``path=path`` 1636 Specifies the export path for the file system device. Files 1637 under this path will be available to the 9p client on the guest. 1638 1639 ``security_model=security_model`` 1640 Specifies the security model to be used for this export path. 1641 Supported security models are "passthrough", "mapped-xattr", 1642 "mapped-file" and "none". In "passthrough" security model, files 1643 are stored using the same credentials as they are created on the 1644 guest. This requires QEMU to run as root. In "mapped-xattr" 1645 security model, some of the file attributes like uid, gid, mode 1646 bits and link target are stored as file attributes. For 1647 "mapped-file" these attributes are stored in the hidden 1648 .virtfs\_metadata directory. Directories exported by this 1649 security model cannot interact with other unix tools. "none" 1650 security model is same as passthrough except the sever won't 1651 report failures if it fails to set file attributes like 1652 ownership. Security model is mandatory only for local fsdriver. 1653 Other fsdrivers (like proxy) don't take security model as a 1654 parameter. 1655 1656 ``writeout=writeout`` 1657 This is an optional argument. The only supported value is 1658 "immediate". This means that host page cache will be used to 1659 read and write data but write notification will be sent to the 1660 guest only when the data has been reported as written by the 1661 storage subsystem. 1662 1663 ``readonly=on`` 1664 Enables exporting 9p share as a readonly mount for guests. By 1665 default read-write access is given. 1666 1667 ``socket=socket`` 1668 Enables proxy filesystem driver to use passed socket file for 1669 communicating with virtfs-proxy-helper(1). Usually a helper like 1670 libvirt will create socketpair and pass one of the fds as 1671 sock\_fd. 1672 1673 ``sock_fd`` 1674 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1675 socket descriptor for interfacing with virtfs-proxy-helper(1). 1676 1677 ``fmode=fmode`` 1678 Specifies the default mode for newly created files on the host. 1679 Works only with security models "mapped-xattr" and 1680 "mapped-file". 1681 1682 ``dmode=dmode`` 1683 Specifies the default mode for newly created directories on the 1684 host. Works only with security models "mapped-xattr" and 1685 "mapped-file". 1686 1687 ``mount_tag=mount_tag`` 1688 Specifies the tag name to be used by the guest to mount this 1689 export point. 1690 1691 ``multidevs=multidevs`` 1692 Specifies how to deal with multiple devices being shared with a 1693 9p export. Supported behaviours are either "remap", "forbid" or 1694 "warn". The latter is the default behaviour on which virtfs 9p 1695 expects only one device to be shared with the same export, and 1696 if more than one device is shared and accessed via the same 9p 1697 export then only a warning message is logged (once) by qemu on 1698 host side. In order to avoid file ID collisions on guest you 1699 should either create a separate virtfs export for each device to 1700 be shared with guests (recommended way) or you might use "remap" 1701 instead which allows you to share multiple devices with only one 1702 export instead, which is achieved by remapping the original 1703 inode numbers from host to guest in a way that would prevent 1704 such collisions. Remapping inodes in such use cases is required 1705 because the original device IDs from host are never passed and 1706 exposed on guest. Instead all files of an export shared with 1707 virtfs always share the same device id on guest. So two files 1708 with identical inode numbers but from actually different devices 1709 on host would otherwise cause a file ID collision and hence 1710 potential misbehaviours on guest. "forbid" on the other hand 1711 assumes like "warn" that only one device is shared by the same 1712 export, however it will not only log a warning message but also 1713 deny access to additional devices on guest. Note though that 1714 "forbid" does currently not block all possible file access 1715 operations (e.g. readdir() would still return entries from other 1716 devices). 1717ERST 1718 1719DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1720 "-iscsi [user=user][,password=password]\n" 1721 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1722 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1723 " [,timeout=timeout]\n" 1724 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1725 1726SRST 1727``-iscsi`` 1728 Configure iSCSI session parameters. 1729ERST 1730 1731DEFHEADING() 1732 1733DEFHEADING(USB convenience options:) 1734 1735DEF("usb", 0, QEMU_OPTION_usb, 1736 "-usb enable on-board USB host controller (if not enabled by default)\n", 1737 QEMU_ARCH_ALL) 1738SRST 1739``-usb`` 1740 Enable USB emulation on machine types with an on-board USB host 1741 controller (if not enabled by default). Note that on-board USB host 1742 controllers may not support USB 3.0. In this case 1743 ``-device qemu-xhci`` can be used instead on machines with PCI. 1744ERST 1745 1746DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1747 "-usbdevice name add the host or guest USB device 'name'\n", 1748 QEMU_ARCH_ALL) 1749SRST 1750``-usbdevice devname`` 1751 Add the USB device devname, and enable an on-board USB controller 1752 if possible and necessary (just like it can be done via 1753 ``-machine usb=on``). Note that this option is mainly intended for 1754 the user's convenience only. More fine-grained control can be 1755 achieved by selecting a USB host controller (if necessary) and the 1756 desired USB device via the ``-device`` option instead. For example, 1757 instead of using ``-usbdevice mouse`` it is possible to use 1758 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1759 to a USB 3.0 controller instead (at least on machines that support 1760 PCI and do not have an USB controller enabled by default yet). 1761 For more details, see the chapter about 1762 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1763 Possible devices for devname are: 1764 1765 ``braille`` 1766 Braille device. This will use BrlAPI to display the braille 1767 output on a real or fake device (i.e. it also creates a 1768 corresponding ``braille`` chardev automatically beside the 1769 ``usb-braille`` USB device). 1770 1771 ``keyboard`` 1772 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1773 1774 ``mouse`` 1775 Virtual Mouse. This will override the PS/2 mouse emulation when 1776 activated. 1777 1778 ``tablet`` 1779 Pointer device that uses absolute coordinates (like a 1780 touchscreen). This means QEMU is able to report the mouse 1781 position without having to grab the mouse. Also overrides the 1782 PS/2 mouse emulation when activated. 1783 1784 ``wacom-tablet`` 1785 Wacom PenPartner USB tablet. 1786 1787 1788ERST 1789 1790DEFHEADING() 1791 1792DEFHEADING(Display options:) 1793 1794DEF("display", HAS_ARG, QEMU_OPTION_display, 1795#if defined(CONFIG_SPICE) 1796 "-display spice-app[,gl=on|off]\n" 1797#endif 1798#if defined(CONFIG_SDL) 1799 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1800 " [,show-cursor=on|off][,window-close=on|off]\n" 1801#endif 1802#if defined(CONFIG_GTK) 1803 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1804 " [,show-cursor=on|off][,window-close=on|off]\n" 1805#endif 1806#if defined(CONFIG_VNC) 1807 "-display vnc=<display>[,<optargs>]\n" 1808#endif 1809#if defined(CONFIG_CURSES) 1810 "-display curses[,charset=<encoding>]\n" 1811#endif 1812#if defined(CONFIG_OPENGL) 1813 "-display egl-headless[,rendernode=<file>]\n" 1814#endif 1815 "-display none\n" 1816 " select display backend type\n" 1817 " The default display is equivalent to\n " 1818#if defined(CONFIG_GTK) 1819 "\"-display gtk\"\n" 1820#elif defined(CONFIG_SDL) 1821 "\"-display sdl\"\n" 1822#elif defined(CONFIG_COCOA) 1823 "\"-display cocoa\"\n" 1824#elif defined(CONFIG_VNC) 1825 "\"-vnc localhost:0,to=99,id=default\"\n" 1826#else 1827 "\"-display none\"\n" 1828#endif 1829 , QEMU_ARCH_ALL) 1830SRST 1831``-display type`` 1832 Select type of display to use. This option is a replacement for the 1833 old style -sdl/-curses/... options. Use ``-display help`` to list 1834 the available display types. Valid values for type are 1835 1836 ``spice-app[,gl=on|off]`` 1837 Start QEMU as a Spice server and launch the default Spice client 1838 application. The Spice server will redirect the serial consoles 1839 and QEMU monitors. (Since 4.0) 1840 1841 ``sdl`` 1842 Display video output via SDL (usually in a separate graphics 1843 window; see the SDL documentation for other possibilities). 1844 Valid parameters are: 1845 1846 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing 1847 1848 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing 1849 1850 ``gl=on|off|core|es`` : Use OpenGL for displaying 1851 1852 ``show-cursor=on|off`` : Force showing the mouse cursor 1853 1854 ``window-close=on|off`` : Allow to quit qemu with window close button 1855 1856 ``gtk`` 1857 Display video output in a GTK window. This interface provides 1858 drop-down menus and other UI elements to configure and control 1859 the VM during runtime. Valid parameters are: 1860 1861 ``full-screen=on|off`` : Start in fullscreen mode 1862 1863 ``gl=on|off`` : Use OpenGL for displaying 1864 1865 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 1866 1867 ``show-cursor=on|off`` : Force showing the mouse cursor 1868 1869 ``window-close=on|off`` : Allow to quit qemu with window close button 1870 1871 ``curses[,charset=<encoding>]`` 1872 Display video output via curses. For graphics device models 1873 which support a text mode, QEMU can display this output using a 1874 curses/ncurses interface. Nothing is displayed when the graphics 1875 device is in graphical mode or if the graphics device does not 1876 support a text mode. Generally only the VGA device models 1877 support text mode. The font charset used by the guest can be 1878 specified with the ``charset`` option, for example 1879 ``charset=CP850`` for IBM CP850 encoding. The default is 1880 ``CP437``. 1881 1882 ``egl-headless[,rendernode=<file>]`` 1883 Offload all OpenGL operations to a local DRI device. For any 1884 graphical display, this display needs to be paired with either 1885 VNC or SPICE displays. 1886 1887 ``vnc=<display>`` 1888 Start a VNC server on display <display> 1889 1890 ``none`` 1891 Do not display video output. The guest will still see an 1892 emulated graphics card, but its output will not be displayed to 1893 the QEMU user. This option differs from the -nographic option in 1894 that it only affects what is done with video output; -nographic 1895 also changes the destination of the serial and parallel port 1896 data. 1897ERST 1898 1899DEF("nographic", 0, QEMU_OPTION_nographic, 1900 "-nographic disable graphical output and redirect serial I/Os to console\n", 1901 QEMU_ARCH_ALL) 1902SRST 1903``-nographic`` 1904 Normally, if QEMU is compiled with graphical window support, it 1905 displays output such as guest graphics, guest console, and the QEMU 1906 monitor in a window. With this option, you can totally disable 1907 graphical output so that QEMU is a simple command line application. 1908 The emulated serial port is redirected on the console and muxed with 1909 the monitor (unless redirected elsewhere explicitly). Therefore, you 1910 can still use QEMU to debug a Linux kernel with a serial console. 1911 Use C-a h for help on switching between the console and monitor. 1912ERST 1913 1914DEF("curses", 0, QEMU_OPTION_curses, 1915 "-curses shorthand for -display curses\n", 1916 QEMU_ARCH_ALL) 1917SRST 1918``-curses`` 1919 Normally, if QEMU is compiled with graphical window support, it 1920 displays output such as guest graphics, guest console, and the QEMU 1921 monitor in a window. With this option, QEMU can display the VGA 1922 output when in text mode using a curses/ncurses interface. Nothing 1923 is displayed in graphical mode. 1924ERST 1925 1926DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1927 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1928 QEMU_ARCH_ALL) 1929SRST 1930``-alt-grab`` 1931 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1932 this also affects the special keys (for fullscreen, monitor-mode 1933 switching, etc). 1934ERST 1935 1936DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1937 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1938 QEMU_ARCH_ALL) 1939SRST 1940``-ctrl-grab`` 1941 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1942 also affects the special keys (for fullscreen, monitor-mode 1943 switching, etc). 1944ERST 1945 1946DEF("no-quit", 0, QEMU_OPTION_no_quit, 1947 "-no-quit disable SDL/GTK window close capability (deprecated)\n", QEMU_ARCH_ALL) 1948SRST 1949``-no-quit`` 1950 Disable window close capability (SDL and GTK only). This option is 1951 deprecated, please use ``-display ...,window-close=off`` instead. 1952ERST 1953 1954DEF("sdl", 0, QEMU_OPTION_sdl, 1955 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1956SRST 1957``-sdl`` 1958 Enable SDL. 1959ERST 1960 1961DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1962 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1963 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1964 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1965 " [,x509-dh-key-file=<file>][,addr=addr]\n" 1966 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 1967 " [,tls-ciphers=<list>]\n" 1968 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1969 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1970 " [,sasl=on|off][,disable-ticketing=on|off]\n" 1971 " [,password=<string>][,password-secret=<secret-id>]\n" 1972 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1973 " [,jpeg-wan-compression=[auto|never|always]]\n" 1974 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1975 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 1976 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 1977 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1978 " [,gl=[on|off]][,rendernode=<file>]\n" 1979 " enable spice\n" 1980 " at least one of {port, tls-port} is mandatory\n", 1981 QEMU_ARCH_ALL) 1982SRST 1983``-spice option[,option[,...]]`` 1984 Enable the spice remote desktop protocol. Valid options are 1985 1986 ``port=<nr>`` 1987 Set the TCP port spice is listening on for plaintext channels. 1988 1989 ``addr=<addr>`` 1990 Set the IP address spice is listening on. Default is any 1991 address. 1992 1993 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 1994 Force using the specified IP version. 1995 1996 ``password=<string>`` 1997 Set the password you need to authenticate. 1998 1999 This option is deprecated and insecure because it leaves the 2000 password visible in the process listing. Use ``password-secret`` 2001 instead. 2002 2003 ``password-secret=<secret-id>`` 2004 Set the ID of the ``secret`` object containing the password 2005 you need to authenticate. 2006 2007 ``sasl=on|off`` 2008 Require that the client use SASL to authenticate with the spice. 2009 The exact choice of authentication method used is controlled 2010 from the system / user's SASL configuration file for the 'qemu' 2011 service. This is typically found in /etc/sasl2/qemu.conf. If 2012 running QEMU as an unprivileged user, an environment variable 2013 SASL\_CONF\_PATH can be used to make it search alternate 2014 locations for the service config. While some SASL auth methods 2015 can also provide data encryption (eg GSSAPI), it is recommended 2016 that SASL always be combined with the 'tls' and 'x509' settings 2017 to enable use of SSL and server certificates. This ensures a 2018 data encryption preventing compromise of authentication 2019 credentials. 2020 2021 ``disable-ticketing=on|off`` 2022 Allow client connects without authentication. 2023 2024 ``disable-copy-paste=on|off`` 2025 Disable copy paste between the client and the guest. 2026 2027 ``disable-agent-file-xfer=on|off`` 2028 Disable spice-vdagent based file-xfer between the client and the 2029 guest. 2030 2031 ``tls-port=<nr>`` 2032 Set the TCP port spice is listening on for encrypted channels. 2033 2034 ``x509-dir=<dir>`` 2035 Set the x509 file directory. Expects same filenames as -vnc 2036 $display,x509=$dir 2037 2038 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2039 The x509 file names can also be configured individually. 2040 2041 ``tls-ciphers=<list>`` 2042 Specify which ciphers to use. 2043 2044 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2045 Force specific channel to be used with or without TLS 2046 encryption. The options can be specified multiple times to 2047 configure multiple channels. The special name "default" can be 2048 used to set the default mode. For channels which are not 2049 explicitly forced into one mode the spice client is allowed to 2050 pick tls/plaintext as he pleases. 2051 2052 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2053 Configure image compression (lossless). Default is auto\_glz. 2054 2055 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2056 Configure wan image compression (lossy for slow links). Default 2057 is auto. 2058 2059 ``streaming-video=[off|all|filter]`` 2060 Configure video stream detection. Default is off. 2061 2062 ``agent-mouse=[on|off]`` 2063 Enable/disable passing mouse events via vdagent. Default is on. 2064 2065 ``playback-compression=[on|off]`` 2066 Enable/disable audio stream compression (using celt 0.5.1). 2067 Default is on. 2068 2069 ``seamless-migration=[on|off]`` 2070 Enable/disable spice seamless migration. Default is off. 2071 2072 ``gl=[on|off]`` 2073 Enable/disable OpenGL context. Default is off. 2074 2075 ``rendernode=<file>`` 2076 DRM render node for OpenGL rendering. If not specified, it will 2077 pick the first available. (Since 2.9) 2078ERST 2079 2080DEF("portrait", 0, QEMU_OPTION_portrait, 2081 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2082 QEMU_ARCH_ALL) 2083SRST 2084``-portrait`` 2085 Rotate graphical output 90 deg left (only PXA LCD). 2086ERST 2087 2088DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2089 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2090 QEMU_ARCH_ALL) 2091SRST 2092``-rotate deg`` 2093 Rotate graphical output some deg left (only PXA LCD). 2094ERST 2095 2096DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2097 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2098 " select video card type\n", QEMU_ARCH_ALL) 2099SRST 2100``-vga type`` 2101 Select type of VGA card to emulate. Valid values for type are 2102 2103 ``cirrus`` 2104 Cirrus Logic GD5446 Video card. All Windows versions starting 2105 from Windows 95 should recognize and use this graphic card. For 2106 optimal performances, use 16 bit color depth in the guest and 2107 the host OS. (This card was the default before QEMU 2.2) 2108 2109 ``std`` 2110 Standard VGA card with Bochs VBE extensions. If your guest OS 2111 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2112 you want to use high resolution modes (>= 1280x1024x16) then you 2113 should use this option. (This card is the default since QEMU 2114 2.2) 2115 2116 ``vmware`` 2117 VMWare SVGA-II compatible adapter. Use it if you have 2118 sufficiently recent XFree86/XOrg server or Windows guest with a 2119 driver for this card. 2120 2121 ``qxl`` 2122 QXL paravirtual graphic card. It is VGA compatible (including 2123 VESA 2.0 VBE support). Works best with qxl guest drivers 2124 installed though. Recommended choice when using the spice 2125 protocol. 2126 2127 ``tcx`` 2128 (sun4m only) Sun TCX framebuffer. This is the default 2129 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2130 colour depths at a fixed resolution of 1024x768. 2131 2132 ``cg3`` 2133 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2134 framebuffer for sun4m machines available in both 1024x768 2135 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2136 wishing to run older Solaris versions. 2137 2138 ``virtio`` 2139 Virtio VGA card. 2140 2141 ``none`` 2142 Disable VGA card. 2143ERST 2144 2145DEF("full-screen", 0, QEMU_OPTION_full_screen, 2146 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2147SRST 2148``-full-screen`` 2149 Start in full screen. 2150ERST 2151 2152DEF("g", HAS_ARG, QEMU_OPTION_g , 2153 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2154 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2155SRST 2156``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2157 Set the initial graphical resolution and depth (PPC, SPARC only). 2158 2159 For PPC the default is 800x600x32. 2160 2161 For SPARC with the TCX graphics device, the default is 1024x768x8 2162 with the option of 1024x768x24. For cgthree, the default is 2163 1024x768x8 with the option of 1152x900x8 for people who wish to use 2164 OBP. 2165ERST 2166 2167DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2168 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2169SRST 2170``-vnc display[,option[,option[,...]]]`` 2171 Normally, if QEMU is compiled with graphical window support, it 2172 displays output such as guest graphics, guest console, and the QEMU 2173 monitor in a window. With this option, you can have QEMU listen on 2174 VNC display display and redirect the VGA display over the VNC 2175 session. It is very useful to enable the usb tablet device when 2176 using this option (option ``-device usb-tablet``). When using the 2177 VNC display, you must use the ``-k`` parameter to set the keyboard 2178 layout if you are not using en-us. Valid syntax for the display is 2179 2180 ``to=L`` 2181 With this option, QEMU will try next available VNC displays, 2182 until the number L, if the origianlly defined "-vnc display" is 2183 not available, e.g. port 5900+display is already used by another 2184 application. By default, to=0. 2185 2186 ``host:d`` 2187 TCP connections will only be allowed from host on display d. By 2188 convention the TCP port is 5900+d. Optionally, host can be 2189 omitted in which case the server will accept connections from 2190 any host. 2191 2192 ``unix:path`` 2193 Connections will be allowed over UNIX domain sockets where path 2194 is the location of a unix socket to listen for connections on. 2195 2196 ``none`` 2197 VNC is initialized but not started. The monitor ``change`` 2198 command can be used to later start the VNC server. 2199 2200 Following the display value there may be one or more option flags 2201 separated by commas. Valid options are 2202 2203 ``reverse=on|off`` 2204 Connect to a listening VNC client via a "reverse" connection. 2205 The client is specified by the display. For reverse network 2206 connections (host:d,``reverse``), the d argument is a TCP port 2207 number, not a display number. 2208 2209 ``websocket=on|off`` 2210 Opens an additional TCP listening port dedicated to VNC 2211 Websocket connections. If a bare websocket option is given, the 2212 Websocket port is 5700+display. An alternative port can be 2213 specified with the syntax ``websocket``\ =port. 2214 2215 If host is specified connections will only be allowed from this 2216 host. It is possible to control the websocket listen address 2217 independently, using the syntax ``websocket``\ =host:port. 2218 2219 If no TLS credentials are provided, the websocket connection 2220 runs in unencrypted mode. If TLS credentials are provided, the 2221 websocket connection requires encrypted client connections. 2222 2223 ``password=on|off`` 2224 Require that password based authentication is used for client 2225 connections. 2226 2227 The password must be set separately using the ``set_password`` 2228 command in the :ref:`QEMU monitor`. The 2229 syntax to change your password is: 2230 ``set_password <protocol> <password>`` where <protocol> could be 2231 either "vnc" or "spice". 2232 2233 If you would like to change <protocol> password expiration, you 2234 should use ``expire_password <protocol> <expiration-time>`` 2235 where expiration time could be one of the following options: 2236 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2237 make password expire in 60 seconds, or 1335196800 to make 2238 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2239 this date and time). 2240 2241 You can also use keywords "now" or "never" for the expiration 2242 time to allow <protocol> password to expire immediately or never 2243 expire. 2244 2245 ``password-secret=<secret-id>`` 2246 Require that password based authentication is used for client 2247 connections, using the password provided by the ``secret`` 2248 object identified by ``secret-id``. 2249 2250 ``tls-creds=ID`` 2251 Provides the ID of a set of TLS credentials to use to secure the 2252 VNC server. They will apply to both the normal VNC server socket 2253 and the websocket socket (if enabled). Setting TLS credentials 2254 will cause the VNC server socket to enable the VeNCrypt auth 2255 mechanism. The credentials should have been previously created 2256 using the ``-object tls-creds`` argument. 2257 2258 ``tls-authz=ID`` 2259 Provides the ID of the QAuthZ authorization object against which 2260 the client's x509 distinguished name will validated. This object 2261 is only resolved at time of use, so can be deleted and recreated 2262 on the fly while the VNC server is active. If missing, it will 2263 default to denying access. 2264 2265 ``sasl=on|off`` 2266 Require that the client use SASL to authenticate with the VNC 2267 server. The exact choice of authentication method used is 2268 controlled from the system / user's SASL configuration file for 2269 the 'qemu' service. This is typically found in 2270 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2271 an environment variable SASL\_CONF\_PATH can be used to make it 2272 search alternate locations for the service config. While some 2273 SASL auth methods can also provide data encryption (eg GSSAPI), 2274 it is recommended that SASL always be combined with the 'tls' 2275 and 'x509' settings to enable use of SSL and server 2276 certificates. This ensures a data encryption preventing 2277 compromise of authentication credentials. See the 2278 :ref:`VNC security` section in the System Emulation Users Guide 2279 for details on using SASL authentication. 2280 2281 ``sasl-authz=ID`` 2282 Provides the ID of the QAuthZ authorization object against which 2283 the client's SASL username will validated. This object is only 2284 resolved at time of use, so can be deleted and recreated on the 2285 fly while the VNC server is active. If missing, it will default 2286 to denying access. 2287 2288 ``acl=on|off`` 2289 Legacy method for enabling authorization of clients against the 2290 x509 distinguished name and SASL username. It results in the 2291 creation of two ``authz-list`` objects with IDs of 2292 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2293 objects must be configured with the HMP ACL commands. 2294 2295 This option is deprecated and should no longer be used. The new 2296 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2297 2298 ``lossy=on|off`` 2299 Enable lossy compression methods (gradient, JPEG, ...). If this 2300 option is set, VNC client may receive lossy framebuffer updates 2301 depending on its encoding settings. Enabling this option can 2302 save a lot of bandwidth at the expense of quality. 2303 2304 ``non-adaptive=on|off`` 2305 Disable adaptive encodings. Adaptive encodings are enabled by 2306 default. An adaptive encoding will try to detect frequently 2307 updated screen regions, and send updates in these regions using 2308 a lossy encoding (like JPEG). This can be really helpful to save 2309 bandwidth when playing videos. Disabling adaptive encodings 2310 restores the original static behavior of encodings like Tight. 2311 2312 ``share=[allow-exclusive|force-shared|ignore]`` 2313 Set display sharing policy. 'allow-exclusive' allows clients to 2314 ask for exclusive access. As suggested by the rfb spec this is 2315 implemented by dropping other connections. Connecting multiple 2316 clients in parallel requires all clients asking for a shared 2317 session (vncviewer: -shared switch). This is the default. 2318 'force-shared' disables exclusive client access. Useful for 2319 shared desktop sessions, where you don't want someone forgetting 2320 specify -shared disconnect everybody else. 'ignore' completely 2321 ignores the shared flag and allows everybody connect 2322 unconditionally. Doesn't conform to the rfb spec but is 2323 traditional QEMU behavior. 2324 2325 ``key-delay-ms`` 2326 Set keyboard delay, for key down and key up events, in 2327 milliseconds. Default is 10. Keyboards are low-bandwidth 2328 devices, so this slowdown can help the device and guest to keep 2329 up and not lose events in case events are arriving in bulk. 2330 Possible causes for the latter are flaky network connections, or 2331 scripts for automated testing. 2332 2333 ``audiodev=audiodev`` 2334 Use the specified audiodev when the VNC client requests audio 2335 transmission. When not using an -audiodev argument, this option 2336 must be omitted, otherwise is must be present and specify a 2337 valid audiodev. 2338 2339 ``power-control=on|off`` 2340 Permit the remote client to issue shutdown, reboot or reset power 2341 control requests. 2342ERST 2343 2344ARCHHEADING(, QEMU_ARCH_I386) 2345 2346ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2347 2348DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2349 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2350 QEMU_ARCH_I386) 2351SRST 2352``-win2k-hack`` 2353 Use it when installing Windows 2000 to avoid a disk full bug. After 2354 Windows 2000 is installed, you no longer need this option (this 2355 option slows down the IDE transfers). 2356ERST 2357 2358DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2359 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2360 QEMU_ARCH_I386) 2361SRST 2362``-no-fd-bootchk`` 2363 Disable boot signature checking for floppy disks in BIOS. May be 2364 needed to boot from old floppy disks. 2365ERST 2366 2367DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2368 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2369SRST 2370``-no-acpi`` 2371 Disable ACPI (Advanced Configuration and Power Interface) support. 2372 Use it if your guest OS complains about ACPI problems (PC target 2373 machine only). 2374ERST 2375 2376DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2377 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2378SRST 2379``-no-hpet`` 2380 Disable HPET support. 2381ERST 2382 2383DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2384 "-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" 2385 " ACPI table description\n", QEMU_ARCH_I386) 2386SRST 2387``-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]...]`` 2388 Add ACPI table with specified header fields and context from 2389 specified files. For file=, take whole ACPI table from the specified 2390 files, including all ACPI headers (possible overridden by other 2391 options). For data=, only data portion of the table is used, all 2392 header information is specified in the command line. If a SLIC table 2393 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2394 fields will override the same in the RSDT and the FADT (a.k.a. 2395 FACP), in order to ensure the field matches required by the 2396 Microsoft SLIC spec and the ACPI spec. 2397ERST 2398 2399DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2400 "-smbios file=binary\n" 2401 " load SMBIOS entry from binary file\n" 2402 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2403 " [,uefi=on|off]\n" 2404 " specify SMBIOS type 0 fields\n" 2405 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2406 " [,uuid=uuid][,sku=str][,family=str]\n" 2407 " specify SMBIOS type 1 fields\n" 2408 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2409 " [,asset=str][,location=str]\n" 2410 " specify SMBIOS type 2 fields\n" 2411 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2412 " [,sku=str]\n" 2413 " specify SMBIOS type 3 fields\n" 2414 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2415 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2416 " specify SMBIOS type 4 fields\n" 2417 "-smbios type=11[,value=str][,path=filename]\n" 2418 " specify SMBIOS type 11 fields\n" 2419 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2420 " [,asset=str][,part=str][,speed=%d]\n" 2421 " specify SMBIOS type 17 fields\n" 2422 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2423 " specify SMBIOS type 41 fields\n", 2424 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2425SRST 2426``-smbios file=binary`` 2427 Load SMBIOS entry from binary file. 2428 2429``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2430 Specify SMBIOS type 0 fields 2431 2432``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2433 Specify SMBIOS type 1 fields 2434 2435``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2436 Specify SMBIOS type 2 fields 2437 2438``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2439 Specify SMBIOS type 3 fields 2440 2441``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2442 Specify SMBIOS type 4 fields 2443 2444``-smbios type=11[,value=str][,path=filename]`` 2445 Specify SMBIOS type 11 fields 2446 2447 This argument can be repeated multiple times, and values are added in the order they are parsed. 2448 Applications intending to use OEM strings data are encouraged to use their application name as 2449 a prefix for the value string. This facilitates passing information for multiple applications 2450 concurrently. 2451 2452 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2453 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2454 2455 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2456 the SMBIOS table in the order in which they appear. 2457 2458 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2459 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2460 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2461 data set, for example, by specifying the serial ID of a block device. 2462 2463 An example passing three strings is 2464 2465 .. parsed-literal:: 2466 2467 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2468 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2469 path=/some/file/with/oemstringsdata.txt 2470 2471 In the guest OS this is visible with the ``dmidecode`` command 2472 2473 .. parsed-literal:: 2474 2475 $ dmidecode -t 11 2476 Handle 0x0E00, DMI type 11, 5 bytes 2477 OEM Strings 2478 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2479 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2480 String 3: myapp:some extra data 2481 2482 2483``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2484 Specify SMBIOS type 17 fields 2485 2486``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2487 Specify SMBIOS type 41 fields 2488 2489 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2490 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2491 position on the PCI bus. 2492 2493 Here is an example of use: 2494 2495 .. parsed-literal:: 2496 2497 -netdev user,id=internet \\ 2498 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2499 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2500 2501 In the guest OS, the device should then appear as ``eno1``: 2502 2503 ..parsed-literal:: 2504 2505 $ ip -brief l 2506 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2507 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2508 2509 Currently, the PCI device has to be attached to the root bus. 2510 2511ERST 2512 2513DEFHEADING() 2514 2515DEFHEADING(Network options:) 2516 2517DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2518#ifdef CONFIG_SLIRP 2519 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2520 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2521 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2522 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2523 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2524#ifndef _WIN32 2525 "[,smb=dir[,smbserver=addr]]\n" 2526#endif 2527 " configure a user mode network backend with ID 'str',\n" 2528 " its DHCP server and optional services\n" 2529#endif 2530#ifdef _WIN32 2531 "-netdev tap,id=str,ifname=name\n" 2532 " configure a host TAP network backend with ID 'str'\n" 2533#else 2534 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2535 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2536 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2537 " [,poll-us=n]\n" 2538 " configure a host TAP network backend with ID 'str'\n" 2539 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2540 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2541 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2542 " to deconfigure it\n" 2543 " use '[down]script=no' to disable script execution\n" 2544 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2545 " configure it\n" 2546 " use 'fd=h' to connect to an already opened TAP interface\n" 2547 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2548 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2549 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2550 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2551 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2552 " use vhost=on to enable experimental in kernel accelerator\n" 2553 " (only has effect for virtio guests which use MSIX)\n" 2554 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2555 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2556 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2557 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2558 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2559 " spent on busy polling for vhost net\n" 2560 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2561 " configure a host TAP network backend with ID 'str' that is\n" 2562 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2563 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2564#endif 2565#ifdef __linux__ 2566 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2567 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2568 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2569 " [,rxcookie=rxcookie][,offset=offset]\n" 2570 " configure a network backend with ID 'str' connected to\n" 2571 " an Ethernet over L2TPv3 pseudowire.\n" 2572 " Linux kernel 3.3+ as well as most routers can talk\n" 2573 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2574 " VM to a router and even VM to Host. It is a nearly-universal\n" 2575 " standard (RFC3931). Note - this implementation uses static\n" 2576 " pre-configured tunnels (same as the Linux kernel).\n" 2577 " use 'src=' to specify source address\n" 2578 " use 'dst=' to specify destination address\n" 2579 " use 'udp=on' to specify udp encapsulation\n" 2580 " use 'srcport=' to specify source udp port\n" 2581 " use 'dstport=' to specify destination udp port\n" 2582 " use 'ipv6=on' to force v6\n" 2583 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2584 " well as a weak security measure\n" 2585 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2586 " use 'txcookie=0x012345678' to specify a txcookie\n" 2587 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2588 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2589 " use 'pincounter=on' to work around broken counter handling in peer\n" 2590 " use 'offset=X' to add an extra offset between header and data\n" 2591#endif 2592 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2593 " configure a network backend to connect to another network\n" 2594 " using a socket connection\n" 2595 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2596 " configure a network backend to connect to a multicast maddr and port\n" 2597 " use 'localaddr=addr' to specify the host address to send packets from\n" 2598 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2599 " configure a network backend to connect to another network\n" 2600 " using an UDP tunnel\n" 2601#ifdef CONFIG_VDE 2602 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2603 " configure a network backend to connect to port 'n' of a vde switch\n" 2604 " running on host and listening for incoming connections on 'socketpath'.\n" 2605 " Use group 'groupname' and mode 'octalmode' to change default\n" 2606 " ownership and permissions for communication port.\n" 2607#endif 2608#ifdef CONFIG_NETMAP 2609 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2610 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2611 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2612 " netmap device, defaults to '/dev/netmap')\n" 2613#endif 2614#ifdef CONFIG_POSIX 2615 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2616 " configure a vhost-user network, backed by a chardev 'dev'\n" 2617#endif 2618#ifdef __linux__ 2619 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2620 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2621#endif 2622 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2623 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2624DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2625 "-nic [tap|bridge|" 2626#ifdef CONFIG_SLIRP 2627 "user|" 2628#endif 2629#ifdef __linux__ 2630 "l2tpv3|" 2631#endif 2632#ifdef CONFIG_VDE 2633 "vde|" 2634#endif 2635#ifdef CONFIG_NETMAP 2636 "netmap|" 2637#endif 2638#ifdef CONFIG_POSIX 2639 "vhost-user|" 2640#endif 2641 "socket][,option][,...][mac=macaddr]\n" 2642 " initialize an on-board / default host NIC (using MAC address\n" 2643 " macaddr) and connect it to the given host network backend\n" 2644 "-nic none use it alone to have zero network devices (the default is to\n" 2645 " provided a 'user' network connection)\n", 2646 QEMU_ARCH_ALL) 2647DEF("net", HAS_ARG, QEMU_OPTION_net, 2648 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2649 " configure or create an on-board (or machine default) NIC and\n" 2650 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2651 "-net [" 2652#ifdef CONFIG_SLIRP 2653 "user|" 2654#endif 2655 "tap|" 2656 "bridge|" 2657#ifdef CONFIG_VDE 2658 "vde|" 2659#endif 2660#ifdef CONFIG_NETMAP 2661 "netmap|" 2662#endif 2663 "socket][,option][,option][,...]\n" 2664 " old way to initialize a host network interface\n" 2665 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2666SRST 2667``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2668 This option is a shortcut for configuring both the on-board 2669 (default) guest NIC hardware and the host network backend in one go. 2670 The host backend options are the same as with the corresponding 2671 ``-netdev`` options below. The guest NIC model can be set with 2672 ``model=modelname``. Use ``model=help`` to list the available device 2673 types. The hardware MAC address can be set with ``mac=macaddr``. 2674 2675 The following two example do exactly the same, to show how ``-nic`` 2676 can be used to shorten the command line length: 2677 2678 .. parsed-literal:: 2679 2680 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2681 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2682 2683``-nic none`` 2684 Indicate that no network devices should be configured. It is used to 2685 override the default configuration (default NIC with "user" host 2686 network backend) which is activated if no other networking options 2687 are provided. 2688 2689``-netdev user,id=id[,option][,option][,...]`` 2690 Configure user mode host network backend which requires no 2691 administrator privilege to run. Valid options are: 2692 2693 ``id=id`` 2694 Assign symbolic name for use in monitor commands. 2695 2696 ``ipv4=on|off and ipv6=on|off`` 2697 Specify that either IPv4 or IPv6 must be enabled. If neither is 2698 specified both protocols are enabled. 2699 2700 ``net=addr[/mask]`` 2701 Set IP network address the guest will see. Optionally specify 2702 the netmask, either in the form a.b.c.d or as number of valid 2703 top-most bits. Default is 10.0.2.0/24. 2704 2705 ``host=addr`` 2706 Specify the guest-visible address of the host. Default is the 2707 2nd IP in the guest network, i.e. x.x.x.2. 2708 2709 ``ipv6-net=addr[/int]`` 2710 Set IPv6 network address the guest will see (default is 2711 fec0::/64). The network prefix is given in the usual hexadecimal 2712 IPv6 address notation. The prefix size is optional, and is given 2713 as the number of valid top-most bits (default is 64). 2714 2715 ``ipv6-host=addr`` 2716 Specify the guest-visible IPv6 address of the host. Default is 2717 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2718 2719 ``restrict=on|off`` 2720 If this option is enabled, the guest will be isolated, i.e. it 2721 will not be able to contact the host and no guest IP packets 2722 will be routed over the host to the outside. This option does 2723 not affect any explicitly set forwarding rules. 2724 2725 ``hostname=name`` 2726 Specifies the client hostname reported by the built-in DHCP 2727 server. 2728 2729 ``dhcpstart=addr`` 2730 Specify the first of the 16 IPs the built-in DHCP server can 2731 assign. Default is the 15th to 31st IP in the guest network, 2732 i.e. x.x.x.15 to x.x.x.31. 2733 2734 ``dns=addr`` 2735 Specify the guest-visible address of the virtual nameserver. The 2736 address must be different from the host address. Default is the 2737 3rd IP in the guest network, i.e. x.x.x.3. 2738 2739 ``ipv6-dns=addr`` 2740 Specify the guest-visible address of the IPv6 virtual 2741 nameserver. The address must be different from the host address. 2742 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2743 2744 ``dnssearch=domain`` 2745 Provides an entry for the domain-search list sent by the 2746 built-in DHCP server. More than one domain suffix can be 2747 transmitted by specifying this option multiple times. If 2748 supported, this will cause the guest to automatically try to 2749 append the given domain suffix(es) in case a domain name can not 2750 be resolved. 2751 2752 Example: 2753 2754 .. parsed-literal:: 2755 2756 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2757 2758 ``domainname=domain`` 2759 Specifies the client domain name reported by the built-in DHCP 2760 server. 2761 2762 ``tftp=dir`` 2763 When using the user mode network stack, activate a built-in TFTP 2764 server. The files in dir will be exposed as the root of a TFTP 2765 server. The TFTP client on the guest must be configured in 2766 binary mode (use the command ``bin`` of the Unix TFTP client). 2767 2768 ``tftp-server-name=name`` 2769 In BOOTP reply, broadcast name as the "TFTP server name" 2770 (RFC2132 option 66). This can be used to advise the guest to 2771 load boot files or configurations from a different server than 2772 the host address. 2773 2774 ``bootfile=file`` 2775 When using the user mode network stack, broadcast file as the 2776 BOOTP filename. In conjunction with ``tftp``, this can be used 2777 to network boot a guest from a local directory. 2778 2779 Example (using pxelinux): 2780 2781 .. parsed-literal:: 2782 2783 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2784 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2785 2786 ``smb=dir[,smbserver=addr]`` 2787 When using the user mode network stack, activate a built-in SMB 2788 server so that Windows OSes can access to the host files in 2789 ``dir`` transparently. The IP address of the SMB server can be 2790 set to addr. By default the 4th IP in the guest network is used, 2791 i.e. x.x.x.4. 2792 2793 In the guest Windows OS, the line: 2794 2795 :: 2796 2797 10.0.2.4 smbserver 2798 2799 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2800 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2801 NT/2000). 2802 2803 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2804 2805 Note that a SAMBA server must be installed on the host OS. 2806 2807 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2808 Redirect incoming TCP or UDP connections to the host port 2809 hostport to the guest IP address guestaddr on guest port 2810 guestport. If guestaddr is not specified, its value is x.x.x.15 2811 (default first address given by the built-in DHCP server). By 2812 specifying hostaddr, the rule can be bound to a specific host 2813 interface. If no connection type is set, TCP is used. This 2814 option can be given multiple times. 2815 2816 For example, to redirect host X11 connection from screen 1 to 2817 guest screen 0, use the following: 2818 2819 .. parsed-literal:: 2820 2821 # on the host 2822 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2823 # this host xterm should open in the guest X11 server 2824 xterm -display :1 2825 2826 To redirect telnet connections from host port 5555 to telnet 2827 port on the guest, use the following: 2828 2829 .. parsed-literal:: 2830 2831 # on the host 2832 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2833 telnet localhost 5555 2834 2835 Then when you use on the host ``telnet localhost 5555``, you 2836 connect to the guest telnet server. 2837 2838 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2839 Forward guest TCP connections to the IP address server on port 2840 port to the character device dev or to a program executed by 2841 cmd:command which gets spawned for each connection. This option 2842 can be given multiple times. 2843 2844 You can either use a chardev directly and have that one used 2845 throughout QEMU's lifetime, like in the following example: 2846 2847 .. parsed-literal:: 2848 2849 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2850 # the guest accesses it 2851 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2852 2853 Or you can execute a command on every TCP connection established 2854 by the guest, so that QEMU behaves similar to an inetd process 2855 for that virtual server: 2856 2857 .. parsed-literal:: 2858 2859 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2860 # and connect the TCP stream to its stdin/stdout 2861 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2862 2863``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2864 Configure a host TAP network backend with ID id. 2865 2866 Use the network script file to configure it and the network script 2867 dfile to deconfigure it. If name is not provided, the OS 2868 automatically provides one. The default network configure script is 2869 ``/etc/qemu-ifup`` and the default network deconfigure script is 2870 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2871 disable script execution. 2872 2873 If running QEMU as an unprivileged user, use the network helper 2874 to configure the TAP interface and attach it to the bridge. 2875 The default network helper executable is 2876 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2877 ``br0``. 2878 2879 ``fd``\ =h can be used to specify the handle of an already opened 2880 host TAP interface. 2881 2882 Examples: 2883 2884 .. parsed-literal:: 2885 2886 #launch a QEMU instance with the default network script 2887 |qemu_system| linux.img -nic tap 2888 2889 .. parsed-literal:: 2890 2891 #launch a QEMU instance with two NICs, each one connected 2892 #to a TAP device 2893 |qemu_system| linux.img \\ 2894 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2895 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2896 2897 .. parsed-literal:: 2898 2899 #launch a QEMU instance with the default network helper to 2900 #connect a TAP device to bridge br0 2901 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2902 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2903 2904``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2905 Connect a host TAP network interface to a host bridge device. 2906 2907 Use the network helper helper to configure the TAP interface and 2908 attach it to the bridge. The default network helper executable is 2909 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2910 ``br0``. 2911 2912 Examples: 2913 2914 .. parsed-literal:: 2915 2916 #launch a QEMU instance with the default network helper to 2917 #connect a TAP device to bridge br0 2918 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2919 2920 .. parsed-literal:: 2921 2922 #launch a QEMU instance with the default network helper to 2923 #connect a TAP device to bridge qemubr0 2924 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2925 2926``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2927 This host network backend can be used to connect the guest's network 2928 to another QEMU virtual machine using a TCP socket connection. If 2929 ``listen`` is specified, QEMU waits for incoming connections on port 2930 (host is optional). ``connect`` is used to connect to another QEMU 2931 instance using the ``listen`` option. ``fd``\ =h specifies an 2932 already opened TCP socket. 2933 2934 Example: 2935 2936 .. parsed-literal:: 2937 2938 # launch a first QEMU instance 2939 |qemu_system| linux.img \\ 2940 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2941 -netdev socket,id=n1,listen=:1234 2942 # connect the network of this instance to the network of the first instance 2943 |qemu_system| linux.img \\ 2944 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2945 -netdev socket,id=n2,connect=127.0.0.1:1234 2946 2947``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2948 Configure a socket host network backend to share the guest's network 2949 traffic with another QEMU virtual machines using a UDP multicast 2950 socket, effectively making a bus for every QEMU with same multicast 2951 address maddr and port. NOTES: 2952 2953 1. Several QEMU can be running on different hosts and share same bus 2954 (assuming correct multicast setup for these hosts). 2955 2956 2. mcast support is compatible with User Mode Linux (argument 2957 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2958 2959 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2960 2961 Example: 2962 2963 .. parsed-literal:: 2964 2965 # launch one QEMU instance 2966 |qemu_system| linux.img \\ 2967 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2968 -netdev socket,id=n1,mcast=230.0.0.1:1234 2969 # launch another QEMU instance on same "bus" 2970 |qemu_system| linux.img \\ 2971 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2972 -netdev socket,id=n2,mcast=230.0.0.1:1234 2973 # launch yet another QEMU instance on same "bus" 2974 |qemu_system| linux.img \\ 2975 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2976 -netdev socket,id=n3,mcast=230.0.0.1:1234 2977 2978 Example (User Mode Linux compat.): 2979 2980 .. parsed-literal:: 2981 2982 # launch QEMU instance (note mcast address selected is UML's default) 2983 |qemu_system| linux.img \\ 2984 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2985 -netdev socket,id=n1,mcast=239.192.168.1:1102 2986 # launch UML 2987 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2988 2989 Example (send packets from host's 1.2.3.4): 2990 2991 .. parsed-literal:: 2992 2993 |qemu_system| linux.img \\ 2994 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2995 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2996 2997``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 2998 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2999 is a popular protocol to transport Ethernet (and other Layer 2) data 3000 frames between two systems. It is present in routers, firewalls and 3001 the Linux kernel (from version 3.3 onwards). 3002 3003 This transport allows a VM to communicate to another VM, router or 3004 firewall directly. 3005 3006 ``src=srcaddr`` 3007 source address (mandatory) 3008 3009 ``dst=dstaddr`` 3010 destination address (mandatory) 3011 3012 ``udp`` 3013 select udp encapsulation (default is ip). 3014 3015 ``srcport=srcport`` 3016 source udp port. 3017 3018 ``dstport=dstport`` 3019 destination udp port. 3020 3021 ``ipv6`` 3022 force v6, otherwise defaults to v4. 3023 3024 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3025 Cookies are a weak form of security in the l2tpv3 specification. 3026 Their function is mostly to prevent misconfiguration. By default 3027 they are 32 bit. 3028 3029 ``cookie64`` 3030 Set cookie size to 64 bit instead of the default 32 3031 3032 ``counter=off`` 3033 Force a 'cut-down' L2TPv3 with no counter as in 3034 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3035 3036 ``pincounter=on`` 3037 Work around broken counter handling in peer. This may also help 3038 on networks which have packet reorder. 3039 3040 ``offset=offset`` 3041 Add an extra offset between header and data 3042 3043 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3044 the bridge br-lan on the remote Linux host 1.2.3.4: 3045 3046 .. parsed-literal:: 3047 3048 # Setup tunnel on linux host using raw ip as encapsulation 3049 # on 1.2.3.4 3050 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3051 encap udp udp_sport 16384 udp_dport 16384 3052 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3053 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3054 ifconfig vmtunnel0 mtu 1500 3055 ifconfig vmtunnel0 up 3056 brctl addif br-lan vmtunnel0 3057 3058 3059 # on 4.3.2.1 3060 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3061 3062 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3063 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3064 3065``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3066 Configure VDE backend to connect to PORT n of a vde switch running 3067 on host and listening for incoming connections on socketpath. Use 3068 GROUP groupname and MODE octalmode to change default ownership and 3069 permissions for communication port. This option is only available if 3070 QEMU has been compiled with vde support enabled. 3071 3072 Example: 3073 3074 .. parsed-literal:: 3075 3076 # launch vde switch 3077 vde_switch -F -sock /tmp/myswitch 3078 # launch QEMU instance 3079 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3080 3081``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3082 Establish a vhost-user netdev, backed by a chardev id. The chardev 3083 should be a unix domain socket backed one. The vhost-user uses a 3084 specifically defined protocol to pass vhost ioctl replacement 3085 messages to an application on the other end of the socket. On 3086 non-MSIX guests, the feature can be forced with vhostforce. Use 3087 'queues=n' to specify the number of queues to be created for 3088 multiqueue vhost-user. 3089 3090 Example: 3091 3092 :: 3093 3094 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3095 -numa node,memdev=mem \ 3096 -chardev socket,id=chr0,path=/path/to/socket \ 3097 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3098 -device virtio-net-pci,netdev=net0 3099 3100``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3101 Establish a vhost-vdpa netdev. 3102 3103 vDPA device is a device that uses a datapath which complies with 3104 the virtio specifications with a vendor specific control path. 3105 vDPA devices can be both physically located on the hardware or 3106 emulated by software. 3107 3108``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3109 Create a hub port on the emulated hub with ID hubid. 3110 3111 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3112 instead of a single netdev. Alternatively, you can also connect the 3113 hubport to another netdev with ID nd by using the ``netdev=nd`` 3114 option. 3115 3116``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3117 Legacy option to configure or create an on-board (or machine 3118 default) Network Interface Card(NIC) and connect it either to the 3119 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3120 If model is omitted, then the default NIC model associated with the 3121 machine type is used. Note that the default NIC model may change in 3122 future QEMU releases, so it is highly recommended to always specify 3123 a model. Optionally, the MAC address can be changed to mac, the 3124 device address set to addr (PCI cards only), and a name can be 3125 assigned for use in monitor commands. Optionally, for PCI cards, you 3126 can specify the number v of MSI-X vectors that the card should have; 3127 this option currently only affects virtio cards; set v = 0 to 3128 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3129 created. QEMU can emulate several different models of network card. 3130 Use ``-net nic,model=help`` for a list of available devices for your 3131 target. 3132 3133``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3134 Configure a host network backend (with the options corresponding to 3135 the same ``-netdev`` option) and connect it to the emulated hub 0 3136 (the default hub). Use name to specify the name of the hub port. 3137ERST 3138 3139DEFHEADING() 3140 3141DEFHEADING(Character device options:) 3142 3143DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3144 "-chardev help\n" 3145 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3146 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3147 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3148 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3149 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3150 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3151 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3152 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3153 " [,logfile=PATH][,logappend=on|off]\n" 3154 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3155 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3156 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3157 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3158 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3159 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3160#ifdef _WIN32 3161 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3162 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3163#else 3164 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3165 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3166#endif 3167#ifdef CONFIG_BRLAPI 3168 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3169#endif 3170#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3171 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3172 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3173 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3174#endif 3175#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3176 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3177 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3178#endif 3179#if defined(CONFIG_SPICE) 3180 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3181 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3182#endif 3183 , QEMU_ARCH_ALL 3184) 3185 3186SRST 3187The general form of a character device option is: 3188 3189``-chardev backend,id=id[,mux=on|off][,options]`` 3190 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3191 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3192 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3193 ``spicevmc``, ``spiceport``. The specific backend will determine the 3194 applicable options. 3195 3196 Use ``-chardev help`` to print all available chardev backend types. 3197 3198 All devices must have an id, which can be any string up to 127 3199 characters long. It is used to uniquely identify this device in 3200 other command line directives. 3201 3202 A character device may be used in multiplexing mode by multiple 3203 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3204 a "1:N" device, and here the "1" end is your specified chardev 3205 backend, and the "N" end is the various parts of QEMU that can talk 3206 to a chardev. If you create a chardev with ``id=myid`` and 3207 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3208 and you can then configure multiple front ends to use that chardev 3209 ID for their input/output. Up to four different front ends can be 3210 connected to a single multiplexed chardev. (Without multiplexing 3211 enabled, a chardev can only be used by a single front end.) For 3212 instance you could use this to allow a single stdio chardev to be 3213 used by two serial ports and the QEMU monitor: 3214 3215 :: 3216 3217 -chardev stdio,mux=on,id=char0 \ 3218 -mon chardev=char0,mode=readline \ 3219 -serial chardev:char0 \ 3220 -serial chardev:char0 3221 3222 You can have more than one multiplexer in a system configuration; 3223 for instance you could have a TCP port multiplexed between UART 0 3224 and UART 1, and stdio multiplexed between the QEMU monitor and a 3225 parallel port: 3226 3227 :: 3228 3229 -chardev stdio,mux=on,id=char0 \ 3230 -mon chardev=char0,mode=readline \ 3231 -parallel chardev:char0 \ 3232 -chardev tcp,...,mux=on,id=char1 \ 3233 -serial chardev:char1 \ 3234 -serial chardev:char1 3235 3236 When you're using a multiplexed character device, some escape 3237 sequences are interpreted in the input. See the chapter about 3238 :ref:`keys in the character backend multiplexer` in the 3239 System Emulation Users Guide for more details. 3240 3241 Note that some other command line options may implicitly create 3242 multiplexed character backends; for instance ``-serial mon:stdio`` 3243 creates a multiplexed stdio backend connected to the serial port and 3244 the QEMU monitor, and ``-nographic`` also multiplexes the console 3245 and the monitor to stdio. 3246 3247 There is currently no support for multiplexing in the other 3248 direction (where a single QEMU front end takes input and output from 3249 multiple chardevs). 3250 3251 Every backend supports the ``logfile`` option, which supplies the 3252 path to a file to record all data transmitted via the backend. The 3253 ``logappend`` option controls whether the log file will be truncated 3254 or appended to when opened. 3255 3256The available backends are: 3257 3258``-chardev null,id=id`` 3259 A void device. This device will not emit any data, and will drop any 3260 data it receives. The null backend does not take any options. 3261 3262``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3263 Create a two-way stream socket, which can be either a TCP or a unix 3264 socket. A unix socket will be created if ``path`` is specified. 3265 Behaviour is undefined if TCP options are specified for a unix 3266 socket. 3267 3268 ``server=on|off`` specifies that the socket shall be a listening socket. 3269 3270 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3271 to connect to a listening socket. 3272 3273 ``telnet=on|off`` specifies that traffic on the socket should interpret 3274 telnet escape sequences. 3275 3276 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3277 communication. 3278 3279 ``reconnect`` sets the timeout for reconnecting on non-server 3280 sockets when the remote end goes away. qemu will delay this many 3281 seconds and then attempt to reconnect. Zero disables reconnecting, 3282 and is the default. 3283 3284 ``tls-creds`` requests enablement of the TLS protocol for 3285 encryption, and specifies the id of the TLS credentials to use for 3286 the handshake. The credentials must be previously created with the 3287 ``-object tls-creds`` argument. 3288 3289 ``tls-auth`` provides the ID of the QAuthZ authorization object 3290 against which the client's x509 distinguished name will be 3291 validated. This object is only resolved at time of use, so can be 3292 deleted and recreated on the fly while the chardev server is active. 3293 If missing, it will default to denying access. 3294 3295 TCP and unix socket options are given below: 3296 3297 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3298 ``host`` for a listening socket specifies the local address to 3299 be bound. For a connecting socket species the remote host to 3300 connect to. ``host`` is optional for listening sockets. If not 3301 specified it defaults to ``0.0.0.0``. 3302 3303 ``port`` for a listening socket specifies the local port to be 3304 bound. For a connecting socket specifies the port on the remote 3305 host to connect to. ``port`` can be given as either a port 3306 number or a service name. ``port`` is required. 3307 3308 ``to`` is only relevant to listening sockets. If it is 3309 specified, and ``port`` cannot be bound, QEMU will attempt to 3310 bind to subsequent ports up to and including ``to`` until it 3311 succeeds. ``to`` must be specified as a port number. 3312 3313 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3314 or IPv6 must be used. If neither is specified the socket may 3315 use either protocol. 3316 3317 ``nodelay=on|off`` disables the Nagle algorithm. 3318 3319 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3320 ``path`` specifies the local path of the unix socket. ``path`` 3321 is required. 3322 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3323 rather than the filesystem. Optional, defaults to false. 3324 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3325 rather than the full sun_path length. Optional, defaults to true. 3326 3327``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3328 Sends all traffic from the guest to a remote host over UDP. 3329 3330 ``host`` specifies the remote host to connect to. If not specified 3331 it defaults to ``localhost``. 3332 3333 ``port`` specifies the port on the remote host to connect to. 3334 ``port`` is required. 3335 3336 ``localaddr`` specifies the local address to bind to. If not 3337 specified it defaults to ``0.0.0.0``. 3338 3339 ``localport`` specifies the local port to bind to. If not specified 3340 any available local port will be used. 3341 3342 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3343 If neither is specified the device may use either protocol. 3344 3345``-chardev msmouse,id=id`` 3346 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3347 does not take any options. 3348 3349``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3350 Connect to a QEMU text console. ``vc`` may optionally be given a 3351 specific size. 3352 3353 ``width`` and ``height`` specify the width and height respectively 3354 of the console, in pixels. 3355 3356 ``cols`` and ``rows`` specify that the console be sized to fit a 3357 text console with the given dimensions. 3358 3359``-chardev ringbuf,id=id[,size=size]`` 3360 Create a ring buffer with fixed size ``size``. size must be a power 3361 of two and defaults to ``64K``. 3362 3363``-chardev file,id=id,path=path`` 3364 Log all traffic received from the guest to a file. 3365 3366 ``path`` specifies the path of the file to be opened. This file will 3367 be created if it does not already exist, and overwritten if it does. 3368 ``path`` is required. 3369 3370``-chardev pipe,id=id,path=path`` 3371 Create a two-way connection to the guest. The behaviour differs 3372 slightly between Windows hosts and other hosts: 3373 3374 On Windows, a single duplex pipe will be created at 3375 ``\\.pipe\path``. 3376 3377 On other hosts, 2 pipes will be created called ``path.in`` and 3378 ``path.out``. Data written to ``path.in`` will be received by the 3379 guest. Data written by the guest can be read from ``path.out``. QEMU 3380 will not create these fifos, and requires them to be present. 3381 3382 ``path`` forms part of the pipe path as described above. ``path`` is 3383 required. 3384 3385``-chardev console,id=id`` 3386 Send traffic from the guest to QEMU's standard output. ``console`` 3387 does not take any options. 3388 3389 ``console`` is only available on Windows hosts. 3390 3391``-chardev serial,id=id,path=path`` 3392 Send traffic from the guest to a serial device on the host. 3393 3394 On Unix hosts serial will actually accept any tty device, not only 3395 serial lines. 3396 3397 ``path`` specifies the name of the serial device to open. 3398 3399``-chardev pty,id=id`` 3400 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3401 does not take any options. 3402 3403 ``pty`` is not available on Windows hosts. 3404 3405``-chardev stdio,id=id[,signal=on|off]`` 3406 Connect to standard input and standard output of the QEMU process. 3407 3408 ``signal`` controls if signals are enabled on the terminal, that 3409 includes exiting QEMU with the key sequence Control-c. This option 3410 is enabled by default, use ``signal=off`` to disable it. 3411 3412``-chardev braille,id=id`` 3413 Connect to a local BrlAPI server. ``braille`` does not take any 3414 options. 3415 3416``-chardev tty,id=id,path=path`` 3417 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3418 and DragonFlyBSD hosts. It is an alias for ``serial``. 3419 3420 ``path`` specifies the path to the tty. ``path`` is required. 3421 3422``-chardev parallel,id=id,path=path`` 3423 \ 3424``-chardev parport,id=id,path=path`` 3425 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3426 hosts. 3427 3428 Connect to a local parallel port. 3429 3430 ``path`` specifies the path to the parallel port device. ``path`` is 3431 required. 3432 3433``-chardev spicevmc,id=id,debug=debug,name=name`` 3434 ``spicevmc`` is only available when spice support is built in. 3435 3436 ``debug`` debug level for spicevmc 3437 3438 ``name`` name of spice channel to connect to 3439 3440 Connect to a spice virtual machine channel, such as vdiport. 3441 3442``-chardev spiceport,id=id,debug=debug,name=name`` 3443 ``spiceport`` is only available when spice support is built in. 3444 3445 ``debug`` debug level for spicevmc 3446 3447 ``name`` name of spice port to connect to 3448 3449 Connect to a spice port, allowing a Spice client to handle the 3450 traffic identified by a name (preferably a fqdn). 3451ERST 3452 3453DEFHEADING() 3454 3455#ifdef CONFIG_TPM 3456DEFHEADING(TPM device options:) 3457 3458DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3459 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3460 " use path to provide path to a character device; default is /dev/tpm0\n" 3461 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3462 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3463 "-tpmdev emulator,id=id,chardev=dev\n" 3464 " configure the TPM device using chardev backend\n", 3465 QEMU_ARCH_ALL) 3466SRST 3467The general form of a TPM device option is: 3468 3469``-tpmdev backend,id=id[,options]`` 3470 The specific backend type will determine the applicable options. The 3471 ``-tpmdev`` option creates the TPM backend and requires a 3472 ``-device`` option that specifies the TPM frontend interface model. 3473 3474 Use ``-tpmdev help`` to print all available TPM backend types. 3475 3476The available backends are: 3477 3478``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3479 (Linux-host only) Enable access to the host's TPM using the 3480 passthrough driver. 3481 3482 ``path`` specifies the path to the host's TPM device, i.e., on a 3483 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3484 default ``/dev/tpm0`` is used. 3485 3486 ``cancel-path`` specifies the path to the host TPM device's sysfs 3487 entry allowing for cancellation of an ongoing TPM command. 3488 ``cancel-path`` is optional and by default QEMU will search for the 3489 sysfs entry to use. 3490 3491 Some notes about using the host's TPM with the passthrough driver: 3492 3493 The TPM device accessed by the passthrough driver must not be used 3494 by any other application on the host. 3495 3496 Since the host's firmware (BIOS/UEFI) has already initialized the 3497 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3498 the TPM again and may therefore not show a TPM-specific menu that 3499 would otherwise allow the user to configure the TPM, e.g., allow the 3500 user to enable/disable or activate/deactivate the TPM. Further, if 3501 TPM ownership is released from within a VM then the host's TPM will 3502 get disabled and deactivated. To enable and activate the TPM again 3503 afterwards, the host has to be rebooted and the user is required to 3504 enter the firmware's menu to enable and activate the TPM. If the TPM 3505 is left disabled and/or deactivated most TPM commands will fail. 3506 3507 To create a passthrough TPM use the following two options: 3508 3509 :: 3510 3511 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3512 3513 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3514 ``tpmdev=tpm0`` in the device option. 3515 3516``-tpmdev emulator,id=id,chardev=dev`` 3517 (Linux-host only) Enable access to a TPM emulator using Unix domain 3518 socket based chardev backend. 3519 3520 ``chardev`` specifies the unique ID of a character device backend 3521 that provides connection to the software TPM server. 3522 3523 To create a TPM emulator backend device with chardev socket backend: 3524 3525 :: 3526 3527 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3528ERST 3529 3530DEFHEADING() 3531 3532#endif 3533 3534DEFHEADING(Linux/Multiboot boot specific:) 3535SRST 3536When using these options, you can use a given Linux or Multiboot kernel 3537without installing it in the disk image. It can be useful for easier 3538testing of various kernels. 3539 3540 3541ERST 3542 3543DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3544 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3545SRST 3546``-kernel bzImage`` 3547 Use bzImage as kernel image. The kernel can be either a Linux kernel 3548 or in multiboot format. 3549ERST 3550 3551DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3552 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3553SRST 3554``-append cmdline`` 3555 Use cmdline as kernel command line 3556ERST 3557 3558DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3559 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3560SRST 3561``-initrd file`` 3562 Use file as initial ram disk. 3563 3564``-initrd "file1 arg=foo,file2"`` 3565 This syntax is only available with multiboot. 3566 3567 Use file1 and file2 as modules and pass arg=foo as parameter to the 3568 first module. 3569ERST 3570 3571DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3572 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3573SRST 3574``-dtb file`` 3575 Use file as a device tree binary (dtb) image and pass it to the 3576 kernel on boot. 3577ERST 3578 3579DEFHEADING() 3580 3581DEFHEADING(Debug/Expert options:) 3582 3583DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3584 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3585 " Policy for handling deprecated management interfaces\n", 3586 QEMU_ARCH_ALL) 3587SRST 3588``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3589 Set policy for handling deprecated management interfaces (experimental): 3590 3591 ``deprecated-input=accept`` (default) 3592 Accept deprecated commands and arguments 3593 ``deprecated-input=reject`` 3594 Reject deprecated commands and arguments 3595 ``deprecated-input=crash`` 3596 Crash on deprecated commands and arguments 3597 ``deprecated-output=accept`` (default) 3598 Emit deprecated command results and events 3599 ``deprecated-output=hide`` 3600 Suppress deprecated command results and events 3601 3602 Limitation: covers only syntactic aspects of QMP. 3603ERST 3604 3605DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3606 "-fw_cfg [name=]<name>,file=<file>\n" 3607 " add named fw_cfg entry with contents from file\n" 3608 "-fw_cfg [name=]<name>,string=<str>\n" 3609 " add named fw_cfg entry with contents from string\n", 3610 QEMU_ARCH_ALL) 3611SRST 3612``-fw_cfg [name=]name,file=file`` 3613 Add named fw\_cfg entry with contents from file file. 3614 3615``-fw_cfg [name=]name,string=str`` 3616 Add named fw\_cfg entry with contents from string str. 3617 3618 The terminating NUL character of the contents of str will not be 3619 included as part of the fw\_cfg item data. To insert contents with 3620 embedded NUL characters, you have to use the file parameter. 3621 3622 The fw\_cfg entries are passed by QEMU through to the guest. 3623 3624 Example: 3625 3626 :: 3627 3628 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3629 3630 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3631 from ./my\_blob.bin. 3632ERST 3633 3634DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3635 "-serial dev redirect the serial port to char device 'dev'\n", 3636 QEMU_ARCH_ALL) 3637SRST 3638``-serial dev`` 3639 Redirect the virtual serial port to host character device dev. The 3640 default device is ``vc`` in graphical mode and ``stdio`` in non 3641 graphical mode. 3642 3643 This option can be used several times to simulate up to 4 serial 3644 ports. 3645 3646 Use ``-serial none`` to disable all serial ports. 3647 3648 Available character devices are: 3649 3650 ``vc[:WxH]`` 3651 Virtual console. Optionally, a width and height can be given in 3652 pixel with 3653 3654 :: 3655 3656 vc:800x600 3657 3658 It is also possible to specify width or height in characters: 3659 3660 :: 3661 3662 vc:80Cx24C 3663 3664 ``pty`` 3665 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3666 3667 ``none`` 3668 No device is allocated. 3669 3670 ``null`` 3671 void device 3672 3673 ``chardev:id`` 3674 Use a named character device defined with the ``-chardev`` 3675 option. 3676 3677 ``/dev/XXX`` 3678 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3679 port parameters are set according to the emulated ones. 3680 3681 ``/dev/parportN`` 3682 [Linux only, parallel port only] Use host parallel port N. 3683 Currently SPP and EPP parallel port features can be used. 3684 3685 ``file:filename`` 3686 Write output to filename. No character can be read. 3687 3688 ``stdio`` 3689 [Unix only] standard input/output 3690 3691 ``pipe:filename`` 3692 name pipe filename 3693 3694 ``COMn`` 3695 [Windows only] Use host serial port n 3696 3697 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3698 This implements UDP Net Console. When remote\_host or src\_ip 3699 are not specified they default to ``0.0.0.0``. When not using a 3700 specified src\_port a random port is automatically chosen. 3701 3702 If you just want a simple readonly console you can use 3703 ``netcat`` or ``nc``, by starting QEMU with: 3704 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3705 QEMU writes something to that port it will appear in the 3706 netconsole session. 3707 3708 If you plan to send characters back via netconsole or you want 3709 to stop and start QEMU a lot of times, you should have QEMU use 3710 the same source port each time by using something like ``-serial 3711 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3712 version of netcat which can listen to a TCP port and send and 3713 receive characters via udp. If you have a patched version of 3714 netcat which activates telnet remote echo and single char 3715 transfer, then you can use the following options to set up a 3716 netcat redirector to allow telnet on port 5555 to access the 3717 QEMU port. 3718 3719 ``QEMU Options:`` 3720 -serial udp::4555@:4556 3721 3722 ``netcat options:`` 3723 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3724 3725 ``telnet options:`` 3726 localhost 5555 3727 3728 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3729 The TCP Net Console has two modes of operation. It can send the 3730 serial I/O to a location or wait for a connection from a 3731 location. By default the TCP Net Console is sent to host at the 3732 port. If you use the ``server=on`` option QEMU will wait for a client 3733 socket application to connect to the port before continuing, 3734 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3735 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3736 option only applies if ``server=no`` is set, if the connection goes 3737 down it will attempt to reconnect at the given interval. If host 3738 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3739 time is accepted. You can use ``telnet=on`` to connect to the 3740 corresponding character device. 3741 3742 ``Example to send tcp console to 192.168.0.2 port 4444`` 3743 -serial tcp:192.168.0.2:4444 3744 3745 ``Example to listen and wait on port 4444 for connection`` 3746 -serial tcp::4444,server=on 3747 3748 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3749 -serial tcp:192.168.0.100:4444,server=on,wait=off 3750 3751 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3752 The telnet protocol is used instead of raw tcp sockets. The 3753 options work the same as if you had specified ``-serial tcp``. 3754 The difference is that the port acts like a telnet server or 3755 client using telnet option negotiation. This will also allow you 3756 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3757 supports sending the break sequence. Typically in unix telnet 3758 you do it with Control-] and then type "send break" followed by 3759 pressing the enter key. 3760 3761 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3762 The WebSocket protocol is used instead of raw tcp socket. The 3763 port acts as a WebSocket server. Client mode is not supported. 3764 3765 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3766 A unix domain socket is used instead of a tcp socket. The option 3767 works the same as if you had specified ``-serial tcp`` except 3768 the unix domain socket path is used for connections. 3769 3770 ``mon:dev_string`` 3771 This is a special option to allow the monitor to be multiplexed 3772 onto another serial port. The monitor is accessed with key 3773 sequence of Control-a and then pressing c. dev\_string should be 3774 any one of the serial devices specified above. An example to 3775 multiplex the monitor onto a telnet server listening on port 3776 4444 would be: 3777 3778 ``-serial mon:telnet::4444,server=on,wait=off`` 3779 3780 When the monitor is multiplexed to stdio in this way, Ctrl+C 3781 will not terminate QEMU any more but will be passed to the guest 3782 instead. 3783 3784 ``braille`` 3785 Braille device. This will use BrlAPI to display the braille 3786 output on a real or fake device. 3787 3788 ``msmouse`` 3789 Three button serial mouse. Configure the guest to use Microsoft 3790 protocol. 3791ERST 3792 3793DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3794 "-parallel dev redirect the parallel port to char device 'dev'\n", 3795 QEMU_ARCH_ALL) 3796SRST 3797``-parallel dev`` 3798 Redirect the virtual parallel port to host device dev (same devices 3799 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3800 to use hardware devices connected on the corresponding host parallel 3801 port. 3802 3803 This option can be used several times to simulate up to 3 parallel 3804 ports. 3805 3806 Use ``-parallel none`` to disable all parallel ports. 3807ERST 3808 3809DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3810 "-monitor dev redirect the monitor to char device 'dev'\n", 3811 QEMU_ARCH_ALL) 3812SRST 3813``-monitor dev`` 3814 Redirect the monitor to host device dev (same devices as the serial 3815 port). The default device is ``vc`` in graphical mode and ``stdio`` 3816 in non graphical mode. Use ``-monitor none`` to disable the default 3817 monitor. 3818ERST 3819DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3820 "-qmp dev like -monitor but opens in 'control' mode\n", 3821 QEMU_ARCH_ALL) 3822SRST 3823``-qmp dev`` 3824 Like -monitor but opens in 'control' mode. 3825ERST 3826DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3827 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3828 QEMU_ARCH_ALL) 3829SRST 3830``-qmp-pretty dev`` 3831 Like -qmp but uses pretty JSON formatting. 3832ERST 3833 3834DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3835 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3836SRST 3837``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3838 Setup monitor on chardev name. ``mode=control`` configures 3839 a QMP monitor (a JSON RPC-style protocol) and it is not the 3840 same as HMP, the human monitor that has a "(qemu)" prompt. 3841 ``pretty`` is only valid when ``mode=control``, 3842 turning on JSON pretty printing to ease 3843 human reading and debugging. 3844ERST 3845 3846DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3847 "-debugcon dev redirect the debug console to char device 'dev'\n", 3848 QEMU_ARCH_ALL) 3849SRST 3850``-debugcon dev`` 3851 Redirect the debug console to host device dev (same devices as the 3852 serial port). The debug console is an I/O port which is typically 3853 port 0xe9; writing to that I/O port sends output to this device. The 3854 default device is ``vc`` in graphical mode and ``stdio`` in non 3855 graphical mode. 3856ERST 3857 3858DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3859 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3860SRST 3861``-pidfile file`` 3862 Store the QEMU process PID in file. It is useful if you launch QEMU 3863 from a script. 3864ERST 3865 3866DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3867 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3868SRST 3869``-singlestep`` 3870 Run the emulation in single step mode. 3871ERST 3872 3873DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3874 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3875 QEMU_ARCH_ALL) 3876SRST 3877``--preconfig`` 3878 Pause QEMU for interactive configuration before the machine is 3879 created, which allows querying and configuring properties that will 3880 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3881 exit the preconfig state and move to the next state (i.e. run guest 3882 if -S isn't used or pause the second time if -S is used). This 3883 option is experimental. 3884ERST 3885 3886DEF("S", 0, QEMU_OPTION_S, \ 3887 "-S freeze CPU at startup (use 'c' to start execution)\n", 3888 QEMU_ARCH_ALL) 3889SRST 3890``-S`` 3891 Do not start CPU at startup (you must type 'c' in the monitor). 3892ERST 3893 3894DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3895 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3896 " run qemu with overcommit hints\n" 3897 " mem-lock=on|off controls memory lock support (default: off)\n" 3898 " cpu-pm=on|off controls cpu power management (default: off)\n", 3899 QEMU_ARCH_ALL) 3900SRST 3901``-overcommit mem-lock=on|off`` 3902 \ 3903``-overcommit cpu-pm=on|off`` 3904 Run qemu with hints about host resource overcommit. The default is 3905 to assume that host overcommits all resources. 3906 3907 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3908 (disabled by default). This works when host memory is not 3909 overcommitted and reduces the worst-case latency for guest. 3910 3911 Guest ability to manage power state of host cpus (increasing latency 3912 for other processes on the same host cpu, but decreasing latency for 3913 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3914 works best when host CPU is not overcommitted. When used, host 3915 estimates of CPU cycle and power utilization will be incorrect, not 3916 taking into account guest idle time. 3917ERST 3918 3919DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3920 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3921 " the guest without waiting for gdb to connect; use -S too\n" 3922 " if you want it to not start execution.)\n", 3923 QEMU_ARCH_ALL) 3924SRST 3925``-gdb dev`` 3926 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3927 in the System Emulation Users Guide). Note that this option does not pause QEMU 3928 execution -- if you want QEMU to not start the guest until you 3929 connect with gdb and issue a ``continue`` command, you will need to 3930 also pass the ``-S`` option to QEMU. 3931 3932 The most usual configuration is to listen on a local TCP socket:: 3933 3934 -gdb tcp::3117 3935 3936 but you can specify other backends; UDP, pseudo TTY, or even stdio 3937 are all reasonable use cases. For example, a stdio connection 3938 allows you to start QEMU from within gdb and establish the 3939 connection via a pipe: 3940 3941 .. parsed-literal:: 3942 3943 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3944ERST 3945 3946DEF("s", 0, QEMU_OPTION_s, \ 3947 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3948 QEMU_ARCH_ALL) 3949SRST 3950``-s`` 3951 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3952 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3953ERST 3954 3955DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3956 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3957 QEMU_ARCH_ALL) 3958SRST 3959``-d item1[,...]`` 3960 Enable logging of specified items. Use '-d help' for a list of log 3961 items. 3962ERST 3963 3964DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3965 "-D logfile output log to logfile (default stderr)\n", 3966 QEMU_ARCH_ALL) 3967SRST 3968``-D logfile`` 3969 Output log in logfile instead of to stderr 3970ERST 3971 3972DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3973 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3974 QEMU_ARCH_ALL) 3975SRST 3976``-dfilter range1[,...]`` 3977 Filter debug output to that relevant to a range of target addresses. 3978 The filter spec can be either start+size, start-size or start..end 3979 where start end and size are the addresses and sizes required. For 3980 example: 3981 3982 :: 3983 3984 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3985 3986 Will dump output for any code in the 0x1000 sized block starting at 3987 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3988 another 0x1000 sized block starting at 0xffffffc00005f000. 3989ERST 3990 3991DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3992 "-seed number seed the pseudo-random number generator\n", 3993 QEMU_ARCH_ALL) 3994SRST 3995``-seed number`` 3996 Force the guest to use a deterministic pseudo-random number 3997 generator, seeded with number. This does not affect crypto routines 3998 within the host. 3999ERST 4000 4001DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4002 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4003 QEMU_ARCH_ALL) 4004SRST 4005``-L path`` 4006 Set the directory for the BIOS, VGA BIOS and keymaps. 4007 4008 To list all the data directories, use ``-L help``. 4009ERST 4010 4011DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4012 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4013SRST 4014``-bios file`` 4015 Set the filename for the BIOS. 4016ERST 4017 4018DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4019 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 4020SRST 4021``-enable-kvm`` 4022 Enable KVM full virtualization support. This option is only 4023 available if KVM support is enabled when compiling. 4024ERST 4025 4026DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4027 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 4028DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4029 "-xen-attach attach to existing xen domain\n" 4030 " libxl will use this when starting QEMU\n", 4031 QEMU_ARCH_ALL) 4032DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4033 "-xen-domid-restrict restrict set of available xen operations\n" 4034 " to specified domain id. (Does not affect\n" 4035 " xenpv machine type).\n", 4036 QEMU_ARCH_ALL) 4037SRST 4038``-xen-domid id`` 4039 Specify xen guest domain id (XEN only). 4040 4041``-xen-attach`` 4042 Attach to existing xen domain. libxl will use this when starting 4043 QEMU (XEN only). Restrict set of available xen operations to 4044 specified domain id (XEN only). 4045ERST 4046 4047DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4048 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4049SRST 4050``-no-reboot`` 4051 Exit instead of rebooting. 4052ERST 4053 4054DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4055 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4056SRST 4057``-no-shutdown`` 4058 Don't exit QEMU on guest shutdown, but instead only stop the 4059 emulation. This allows for instance switching to monitor to commit 4060 changes to the disk image. 4061ERST 4062 4063DEF("action", HAS_ARG, QEMU_OPTION_action, 4064 "-action reboot=reset|shutdown\n" 4065 " action when guest reboots [default=reset]\n" 4066 "-action shutdown=poweroff|pause\n" 4067 " action when guest shuts down [default=poweroff]\n" 4068 "-action panic=pause|shutdown|none\n" 4069 " action when guest panics [default=shutdown]\n" 4070 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4071 " action when watchdog fires [default=reset]\n", 4072 QEMU_ARCH_ALL) 4073SRST 4074``-action event=action`` 4075 The action parameter serves to modify QEMU's default behavior when 4076 certain guest events occur. It provides a generic method for specifying the 4077 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4078 parameters. 4079 4080 Examples: 4081 4082 ``-action panic=none`` 4083 ``-action reboot=shutdown,shutdown=pause`` 4084 ``-watchdog i6300esb -action watchdog=pause`` 4085 4086ERST 4087 4088DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4089 "-loadvm [tag|id]\n" \ 4090 " start right away with a saved state (loadvm in monitor)\n", 4091 QEMU_ARCH_ALL) 4092SRST 4093``-loadvm file`` 4094 Start right away with a saved state (``loadvm`` in monitor) 4095ERST 4096 4097#ifndef _WIN32 4098DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4099 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4100#endif 4101SRST 4102``-daemonize`` 4103 Daemonize the QEMU process after initialization. QEMU will not 4104 detach from standard IO until it is ready to receive connections on 4105 any of its devices. This option is a useful way for external 4106 programs to launch QEMU without having to cope with initialization 4107 race conditions. 4108ERST 4109 4110DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4111 "-option-rom rom load a file, rom, into the option ROM space\n", 4112 QEMU_ARCH_ALL) 4113SRST 4114``-option-rom file`` 4115 Load the contents of file as an option ROM. This option is useful to 4116 load things like EtherBoot. 4117ERST 4118 4119DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4120 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4121 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4122 QEMU_ARCH_ALL) 4123 4124SRST 4125``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4126 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4127 the current UTC or local time, respectively. ``localtime`` is 4128 required for correct date in MS-DOS or Windows. To start at a 4129 specific point in time, provide datetime in the format 4130 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4131 4132 By default the RTC is driven by the host system time. This allows 4133 using of the RTC as accurate reference clock inside the guest, 4134 specifically if the host time is smoothly following an accurate 4135 external reference clock, e.g. via NTP. If you want to isolate the 4136 guest time from the host, you can set ``clock`` to ``rt`` instead, 4137 which provides a host monotonic clock if host support it. To even 4138 prevent the RTC from progressing during suspension, you can set 4139 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4140 recommended especially in icount mode in order to preserve 4141 determinism; however, note that in icount mode the speed of the 4142 virtual clock is variable and can in general differ from the host 4143 clock. 4144 4145 Enable ``driftfix`` (i386 targets only) if you experience time drift 4146 problems, specifically with Windows' ACPI HAL. This option will try 4147 to figure out how many timer interrupts were not processed by the 4148 Windows guest and will re-inject them. 4149ERST 4150 4151DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4152 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4153 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4154 " instruction, enable aligning the host and virtual clocks\n" \ 4155 " or disable real time cpu sleeping, and optionally enable\n" \ 4156 " record-and-replay mode\n", QEMU_ARCH_ALL) 4157SRST 4158``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4159 Enable virtual instruction counter. The virtual cpu will execute one 4160 instruction every 2^N ns of virtual time. If ``auto`` is specified 4161 then the virtual cpu speed will be automatically adjusted to keep 4162 virtual time within a few seconds of real time. 4163 4164 Note that while this option can give deterministic behavior, it does 4165 not provide cycle accurate emulation. Modern CPUs contain 4166 superscalar out of order cores with complex cache hierarchies. The 4167 number of instructions executed often has little or no correlation 4168 with actual performance. 4169 4170 When the virtual cpu is sleeping, the virtual time will advance at 4171 default speed unless ``sleep=on`` is specified. With 4172 ``sleep=on``, the virtual time will jump to the next timer 4173 deadline instantly whenever the virtual cpu goes to sleep mode and 4174 will not advance if no timer is enabled. This behavior gives 4175 deterministic execution times from the guest point of view. 4176 The default if icount is enabled is ``sleep=off``. 4177 ``sleep=on`` cannot be used together with either ``shift=auto`` 4178 or ``align=on``. 4179 4180 ``align=on`` will activate the delay algorithm which will try to 4181 synchronise the host clock and the virtual clock. The goal is to 4182 have a guest running at the real frequency imposed by the shift 4183 option. Whenever the guest clock is behind the host clock and if 4184 ``align=on`` is specified then we print a message to the user to 4185 inform about the delay. Currently this option does not work when 4186 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4187 shift values for which the guest clock runs ahead of the host clock. 4188 Typically this happens when the shift value is high (how high 4189 depends on the host machine). The default if icount is enabled 4190 is ``align=off``. 4191 4192 When the ``rr`` option is specified deterministic record/replay is 4193 enabled. The ``rrfile=`` option must also be provided to 4194 specify the path to the replay log. In record mode data is written 4195 to this file, and in replay mode it is read back. 4196 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4197 name. In record mode, a new VM snapshot with the given name is created 4198 at the start of execution recording. In replay mode this option 4199 specifies the snapshot name used to load the initial VM state. 4200ERST 4201 4202DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4203 "-watchdog model\n" \ 4204 " enable virtual hardware watchdog [default=none]\n", 4205 QEMU_ARCH_ALL) 4206SRST 4207``-watchdog model`` 4208 Create a virtual hardware watchdog device. Once enabled (by a guest 4209 action), the watchdog must be periodically polled by an agent inside 4210 the guest or else the guest will be restarted. Choose a model for 4211 which your guest has drivers. 4212 4213 The model is the model of hardware watchdog to emulate. Use 4214 ``-watchdog help`` to list available hardware models. Only one 4215 watchdog can be enabled for a guest. 4216 4217 The following models may be available: 4218 4219 ``ib700`` 4220 iBASE 700 is a very simple ISA watchdog with a single timer. 4221 4222 ``i6300esb`` 4223 Intel 6300ESB I/O controller hub is a much more featureful 4224 PCI-based dual-timer watchdog. 4225 4226 ``diag288`` 4227 A virtual watchdog for s390x backed by the diagnose 288 4228 hypercall (currently KVM only). 4229ERST 4230 4231DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4232 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4233 " action when watchdog fires [default=reset]\n", 4234 QEMU_ARCH_ALL) 4235SRST 4236``-watchdog-action action`` 4237 The action controls what QEMU will do when the watchdog timer 4238 expires. The default is ``reset`` (forcefully reset the guest). 4239 Other possible actions are: ``shutdown`` (attempt to gracefully 4240 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4241 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4242 guest), ``debug`` (print a debug message and continue), or ``none`` 4243 (do nothing). 4244 4245 Note that the ``shutdown`` action requires that the guest responds 4246 to ACPI signals, which it may not be able to do in the sort of 4247 situations where the watchdog would have expired, and thus 4248 ``-watchdog-action shutdown`` is not recommended for production use. 4249 4250 Examples: 4251 4252 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4253 4254ERST 4255 4256DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4257 "-echr chr set terminal escape character instead of ctrl-a\n", 4258 QEMU_ARCH_ALL) 4259SRST 4260``-echr numeric_ascii_value`` 4261 Change the escape character used for switching to the monitor when 4262 using monitor and serial sharing. The default is ``0x01`` when using 4263 the ``-nographic`` option. ``0x01`` is equal to pressing 4264 ``Control-a``. You can select a different character from the ascii 4265 control keys where 1 through 26 map to Control-a through Control-z. 4266 For instance you could use the either of the following to change the 4267 escape character to Control-t. 4268 4269 ``-echr 0x14``; \ ``-echr 20`` 4270 4271ERST 4272 4273DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4274 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4275 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4276 "-incoming unix:socketpath\n" \ 4277 " prepare for incoming migration, listen on\n" \ 4278 " specified protocol and socket address\n" \ 4279 "-incoming fd:fd\n" \ 4280 "-incoming exec:cmdline\n" \ 4281 " accept incoming migration on given file descriptor\n" \ 4282 " or from given external command\n" \ 4283 "-incoming defer\n" \ 4284 " wait for the URI to be specified via migrate_incoming\n", 4285 QEMU_ARCH_ALL) 4286SRST 4287``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4288 \ 4289``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4290 Prepare for incoming migration, listen on a given tcp port. 4291 4292``-incoming unix:socketpath`` 4293 Prepare for incoming migration, listen on a given unix socket. 4294 4295``-incoming fd:fd`` 4296 Accept incoming migration from a given filedescriptor. 4297 4298``-incoming exec:cmdline`` 4299 Accept incoming migration as an output from specified external 4300 command. 4301 4302``-incoming defer`` 4303 Wait for the URI to be specified via migrate\_incoming. The monitor 4304 can be used to change settings (such as migration parameters) prior 4305 to issuing the migrate\_incoming to allow the migration to begin. 4306ERST 4307 4308DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4309 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4310SRST 4311``-only-migratable`` 4312 Only allow migratable devices. Devices will not be allowed to enter 4313 an unmigratable state. 4314ERST 4315 4316DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4317 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4318SRST 4319``-nodefaults`` 4320 Don't create default devices. Normally, QEMU sets the default 4321 devices like serial port, parallel port, virtual console, monitor 4322 device, VGA adapter, floppy and CD-ROM drive and others. The 4323 ``-nodefaults`` option will disable all those default devices. 4324ERST 4325 4326#ifndef _WIN32 4327DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4328 "-chroot dir chroot to dir just before starting the VM\n", 4329 QEMU_ARCH_ALL) 4330#endif 4331SRST 4332``-chroot dir`` 4333 Immediately before starting guest execution, chroot to the specified 4334 directory. Especially useful in combination with -runas. 4335ERST 4336 4337#ifndef _WIN32 4338DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4339 "-runas user change to user id user just before starting the VM\n" \ 4340 " user can be numeric uid:gid instead\n", 4341 QEMU_ARCH_ALL) 4342#endif 4343SRST 4344``-runas user`` 4345 Immediately before starting guest execution, drop root privileges, 4346 switching to the specified user. 4347ERST 4348 4349DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4350 "-prom-env variable=value\n" 4351 " set OpenBIOS nvram variables\n", 4352 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4353SRST 4354``-prom-env variable=value`` 4355 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4356 4357 :: 4358 4359 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4360 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4361 4362 :: 4363 4364 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4365 -prom-env 'boot-device=hd:2,\yaboot' \ 4366 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4367ERST 4368DEF("semihosting", 0, QEMU_OPTION_semihosting, 4369 "-semihosting semihosting mode\n", 4370 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4371 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4372SRST 4373``-semihosting`` 4374 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4375 4376 Note that this allows guest direct access to the host filesystem, so 4377 should only be used with a trusted guest OS. 4378 4379 See the -semihosting-config option documentation for further 4380 information about the facilities this enables. 4381ERST 4382DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4383 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4384 " semihosting configuration\n", 4385QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4386QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4387SRST 4388``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4389 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4390 only). 4391 4392 Note that this allows guest direct access to the host filesystem, so 4393 should only be used with a trusted guest OS. 4394 4395 On Arm this implements the standard semihosting API, version 2.0. 4396 4397 On M68K this implements the "ColdFire GDB" interface used by 4398 libgloss. 4399 4400 Xtensa semihosting provides basic file IO calls, such as 4401 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4402 linux platform "sim" use this interface. 4403 4404 On RISC-V this implements the standard semihosting API, version 0.2. 4405 4406 ``target=native|gdb|auto`` 4407 Defines where the semihosting calls will be addressed, to QEMU 4408 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4409 means ``gdb`` during debug sessions and ``native`` otherwise. 4410 4411 ``chardev=str1`` 4412 Send the output to a chardev backend output for native or auto 4413 output when not in gdb 4414 4415 ``arg=str1,arg=str2,...`` 4416 Allows the user to pass input arguments, and can be used 4417 multiple times to build up a list. The old-style 4418 ``-kernel``/``-append`` method of passing a command line is 4419 still supported for backward compatibility. If both the 4420 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4421 specified, the former is passed to semihosting as it always 4422 takes precedence. 4423ERST 4424DEF("old-param", 0, QEMU_OPTION_old_param, 4425 "-old-param old param mode\n", QEMU_ARCH_ARM) 4426SRST 4427``-old-param`` 4428 Old param mode (ARM only). 4429ERST 4430 4431DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4432 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4433 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4434 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4435 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4436 " by the kernel, but typically no longer used by modern\n" \ 4437 " C library implementations.\n" \ 4438 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4439 " to elevate privileges using set*uid|gid system calls.\n" \ 4440 " The value 'children' will deny set*uid|gid system calls for\n" \ 4441 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4442 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4443 " blocking *fork and execve\n" \ 4444 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4445 QEMU_ARCH_ALL) 4446SRST 4447``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4448 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4449 filtering and 'off' will disable it. The default is 'off'. 4450 4451 ``obsolete=string`` 4452 Enable Obsolete system calls 4453 4454 ``elevateprivileges=string`` 4455 Disable set\*uid\|gid system calls 4456 4457 ``spawn=string`` 4458 Disable \*fork and execve 4459 4460 ``resourcecontrol=string`` 4461 Disable process affinity and schedular priority 4462ERST 4463 4464DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4465 "-readconfig <file>\n", QEMU_ARCH_ALL) 4466SRST 4467``-readconfig file`` 4468 Read device configuration from file. This approach is useful when 4469 you want to spawn QEMU process with many command line options but 4470 you don't want to exceed the command line character limit. 4471ERST 4472DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4473 "-writeconfig <file>\n" 4474 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4475SRST 4476ERST 4477 4478DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4479 "-no-user-config\n" 4480 " do not load default user-provided config files at startup\n", 4481 QEMU_ARCH_ALL) 4482SRST 4483``-no-user-config`` 4484 The ``-no-user-config`` option makes QEMU not load any of the 4485 user-provided config files on sysconfdir. 4486ERST 4487 4488DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4489 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4490 " specify tracing options\n", 4491 QEMU_ARCH_ALL) 4492SRST 4493``-trace [[enable=]pattern][,events=file][,file=file]`` 4494 .. include:: ../qemu-option-trace.rst.inc 4495 4496ERST 4497DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4498 "-plugin [file=]<file>[,arg=<string>]\n" 4499 " load a plugin\n", 4500 QEMU_ARCH_ALL) 4501SRST 4502``-plugin file=file[,arg=string]`` 4503 Load a plugin. 4504 4505 ``file=file`` 4506 Load the given plugin from a shared library file. 4507 4508 ``arg=string`` 4509 Argument string passed to the plugin. (Can be given multiple 4510 times.) 4511ERST 4512 4513HXCOMM Internal use 4514DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4515DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4516 4517#ifdef __linux__ 4518DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4519 "-enable-fips enable FIPS 140-2 compliance\n", 4520 QEMU_ARCH_ALL) 4521#endif 4522SRST 4523``-enable-fips`` 4524 Enable FIPS 140-2 compliance mode. 4525ERST 4526 4527DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4528 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4529 " control error message format\n" 4530 " timestamp=on enables timestamps (default: off)\n" 4531 " guest-name=on enables guest name prefix but only if\n" 4532 " -name guest option is set (default: off)\n", 4533 QEMU_ARCH_ALL) 4534SRST 4535``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4536 Control error message format. 4537 4538 ``timestamp=on|off`` 4539 Prefix messages with a timestamp. Default is off. 4540 4541 ``guest-name=on|off`` 4542 Prefix messages with guest name but only if -name guest option is set 4543 otherwise the option is ignored. Default is off. 4544ERST 4545 4546DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4547 "-dump-vmstate <file>\n" 4548 " Output vmstate information in JSON format to file.\n" 4549 " Use the scripts/vmstate-static-checker.py file to\n" 4550 " check for possible regressions in migration code\n" 4551 " by comparing two such vmstate dumps.\n", 4552 QEMU_ARCH_ALL) 4553SRST 4554``-dump-vmstate file`` 4555 Dump json-encoded vmstate information for current machine type to 4556 file in file 4557ERST 4558 4559DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4560 "-enable-sync-profile\n" 4561 " enable synchronization profiling\n", 4562 QEMU_ARCH_ALL) 4563SRST 4564``-enable-sync-profile`` 4565 Enable synchronization profiling. 4566ERST 4567 4568DEFHEADING() 4569 4570DEFHEADING(Generic object creation:) 4571 4572DEF("object", HAS_ARG, QEMU_OPTION_object, 4573 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4574 " create a new object of type TYPENAME setting properties\n" 4575 " in the order they are specified. Note that the 'id'\n" 4576 " property must be set. These objects are placed in the\n" 4577 " '/objects' path.\n", 4578 QEMU_ARCH_ALL) 4579SRST 4580``-object typename[,prop1=value1,...]`` 4581 Create a new object of type typename setting properties in the order 4582 they are specified. Note that the 'id' property must be set. These 4583 objects are placed in the '/objects' path. 4584 4585 ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,readonly=on|off`` 4586 Creates a memory file backend object, which can be used to back 4587 the guest RAM with huge pages. 4588 4589 The ``id`` parameter is a unique ID that will be used to 4590 reference this memory region in other parameters, e.g. ``-numa``, 4591 ``-device nvdimm``, etc. 4592 4593 The ``size`` option provides the size of the memory region, and 4594 accepts common suffixes, e.g. ``500M``. 4595 4596 The ``mem-path`` provides the path to either a shared memory or 4597 huge page filesystem mount. 4598 4599 The ``share`` boolean option determines whether the memory 4600 region is marked as private to QEMU, or shared. The latter 4601 allows a co-operating external process to access the QEMU memory 4602 region. 4603 4604 The ``share`` is also required for pvrdma devices due to 4605 limitations in the RDMA API provided by Linux. 4606 4607 Setting share=on might affect the ability to configure NUMA 4608 bindings for the memory backend under some circumstances, see 4609 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4610 source tree for additional details. 4611 4612 Setting the ``discard-data`` boolean option to on indicates that 4613 file contents can be destroyed when QEMU exits, to avoid 4614 unnecessarily flushing data to the backing file. Note that 4615 ``discard-data`` is only an optimization, and QEMU might not 4616 discard file contents if it aborts unexpectedly or is terminated 4617 using SIGKILL. 4618 4619 The ``merge`` boolean option enables memory merge, also known as 4620 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4621 the pages for memory deduplication. 4622 4623 Setting the ``dump`` boolean option to off excludes the memory 4624 from core dumps. This feature is also known as MADV\_DONTDUMP. 4625 4626 The ``prealloc`` boolean option enables memory preallocation. 4627 4628 The ``host-nodes`` option binds the memory range to a list of 4629 NUMA host nodes. 4630 4631 The ``policy`` option sets the NUMA policy to one of the 4632 following values: 4633 4634 ``default`` 4635 default host policy 4636 4637 ``preferred`` 4638 prefer the given host node list for allocation 4639 4640 ``bind`` 4641 restrict memory allocation to the given host node list 4642 4643 ``interleave`` 4644 interleave memory allocations across the given host node 4645 list 4646 4647 The ``align`` option specifies the base address alignment when 4648 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4649 ``2M``. Some backend store specified by ``mem-path`` requires an 4650 alignment different than the default one used by QEMU, eg the 4651 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4652 such cases, users can specify the required alignment via this 4653 option. 4654 4655 The ``pmem`` option specifies whether the backing file specified 4656 by ``mem-path`` is in host persistent memory that can be 4657 accessed using the SNIA NVM programming model (e.g. Intel 4658 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4659 operations to guarantee the persistence of its own writes to 4660 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4661 migration). Also, we will map the backend-file with MAP\_SYNC 4662 flag, which ensures the file metadata is in sync for 4663 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4664 requires support from both the host kernel (since Linux kernel 4665 4.15) and the filesystem of ``mem-path`` mounted with DAX 4666 option. 4667 4668 The ``readonly`` option specifies whether the backing file is opened 4669 read-only or read-write (default). 4670 4671 ``-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`` 4672 Creates a memory backend object, which can be used to back the 4673 guest RAM. Memory backend objects offer more control than the 4674 ``-m`` option that is traditionally used to define guest RAM. 4675 Please refer to ``memory-backend-file`` for a description of the 4676 options. 4677 4678 ``-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`` 4679 Creates an anonymous memory file backend object, which allows 4680 QEMU to share the memory with an external process (e.g. when 4681 using vhost-user). The memory is allocated with memfd and 4682 optional sealing. (Linux only) 4683 4684 The ``seal`` option creates a sealed-file, that will block 4685 further resizing the memory ('on' by default). 4686 4687 The ``hugetlb`` option specify the file to be created resides in 4688 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4689 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4690 the hugetlb page size on systems that support multiple hugetlb 4691 page sizes (it must be a power of 2 value supported by the 4692 system). 4693 4694 In some versions of Linux, the ``hugetlb`` option is 4695 incompatible with the ``seal`` option (requires at least Linux 4696 4.16). 4697 4698 Please refer to ``memory-backend-file`` for a description of the 4699 other options. 4700 4701 The ``share`` boolean option is on by default with memfd. 4702 4703 ``-object rng-builtin,id=id`` 4704 Creates a random number generator backend which obtains entropy 4705 from QEMU builtin functions. The ``id`` parameter is a unique ID 4706 that will be used to reference this entropy backend from the 4707 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4708 uses this RNG backend. 4709 4710 ``-object rng-random,id=id,filename=/dev/random`` 4711 Creates a random number generator backend which obtains entropy 4712 from a device on the host. The ``id`` parameter is a unique ID 4713 that will be used to reference this entropy backend from the 4714 ``virtio-rng`` device. The ``filename`` parameter specifies 4715 which file to obtain entropy from and if omitted defaults to 4716 ``/dev/urandom``. 4717 4718 ``-object rng-egd,id=id,chardev=chardevid`` 4719 Creates a random number generator backend which obtains entropy 4720 from an external daemon running on the host. The ``id`` 4721 parameter is a unique ID that will be used to reference this 4722 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4723 parameter is the unique ID of a character device backend that 4724 provides the connection to the RNG daemon. 4725 4726 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4727 Creates a TLS anonymous credentials object, which can be used to 4728 provide TLS support on network backends. The ``id`` parameter is 4729 a unique ID which network backends will use to access the 4730 credentials. The ``endpoint`` is either ``server`` or ``client`` 4731 depending on whether the QEMU network backend that uses the 4732 credentials will be acting as a client or as a server. If 4733 ``verify-peer`` is enabled (the default) then once the handshake 4734 is completed, the peer credentials will be verified, though this 4735 is a no-op for anonymous credentials. 4736 4737 The dir parameter tells QEMU where to find the credential files. 4738 For server endpoints, this directory may contain a file 4739 dh-params.pem providing diffie-hellman parameters to use for the 4740 TLS server. If the file is missing, QEMU will generate a set of 4741 DH parameters at startup. This is a computationally expensive 4742 operation that consumes random pool entropy, so it is 4743 recommended that a persistent set of parameters be generated 4744 upfront and saved. 4745 4746 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4747 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4748 can be used to provide TLS support on network backends. The 4749 ``id`` parameter is a unique ID which network backends will use 4750 to access the credentials. The ``endpoint`` is either ``server`` 4751 or ``client`` depending on whether the QEMU network backend that 4752 uses the credentials will be acting as a client or as a server. 4753 For clients only, ``username`` is the username which will be 4754 sent to the server. If omitted it defaults to "qemu". 4755 4756 The dir parameter tells QEMU where to find the keys file. It is 4757 called "dir/keys.psk" and contains "username:key" pairs. This 4758 file can most easily be created using the GnuTLS ``psktool`` 4759 program. 4760 4761 For server endpoints, dir may also contain a file dh-params.pem 4762 providing diffie-hellman parameters to use for the TLS server. 4763 If the file is missing, QEMU will generate a set of DH 4764 parameters at startup. This is a computationally expensive 4765 operation that consumes random pool entropy, so it is 4766 recommended that a persistent set of parameters be generated up 4767 front and saved. 4768 4769 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4770 Creates a TLS anonymous credentials object, which can be used to 4771 provide TLS support on network backends. The ``id`` parameter is 4772 a unique ID which network backends will use to access the 4773 credentials. The ``endpoint`` is either ``server`` or ``client`` 4774 depending on whether the QEMU network backend that uses the 4775 credentials will be acting as a client or as a server. If 4776 ``verify-peer`` is enabled (the default) then once the handshake 4777 is completed, the peer credentials will be verified. With x509 4778 certificates, this implies that the clients must be provided 4779 with valid client certificates too. 4780 4781 The dir parameter tells QEMU where to find the credential files. 4782 For server endpoints, this directory may contain a file 4783 dh-params.pem providing diffie-hellman parameters to use for the 4784 TLS server. If the file is missing, QEMU will generate a set of 4785 DH parameters at startup. This is a computationally expensive 4786 operation that consumes random pool entropy, so it is 4787 recommended that a persistent set of parameters be generated 4788 upfront and saved. 4789 4790 For x509 certificate credentials the directory will contain 4791 further files providing the x509 certificates. The certificates 4792 must be stored in PEM format, in filenames ca-cert.pem, 4793 ca-crl.pem (optional), server-cert.pem (only servers), 4794 server-key.pem (only servers), client-cert.pem (only clients), 4795 and client-key.pem (only clients). 4796 4797 For the server-key.pem and client-key.pem files which contain 4798 sensitive private keys, it is possible to use an encrypted 4799 version by providing the passwordid parameter. This provides the 4800 ID of a previously created ``secret`` object containing the 4801 password for decryption. 4802 4803 The priority parameter allows to override the global default 4804 priority used by gnutls. This can be useful if the system 4805 administrator needs to use a weaker set of crypto priorities for 4806 QEMU without potentially forcing the weakness onto all 4807 applications. Or conversely if one wants wants a stronger 4808 default for QEMU than for all other applications, they can do 4809 this through this parameter. Its format is a gnutls priority 4810 string as described at 4811 https://gnutls.org/manual/html_node/Priority-Strings.html. 4812 4813 ``-object tls-cipher-suites,id=id,priority=priority`` 4814 Creates a TLS cipher suites object, which can be used to control 4815 the TLS cipher/protocol algorithms that applications are permitted 4816 to use. 4817 4818 The ``id`` parameter is a unique ID which frontends will use to 4819 access the ordered list of permitted TLS cipher suites from the 4820 host. 4821 4822 The ``priority`` parameter allows to override the global default 4823 priority used by gnutls. This can be useful if the system 4824 administrator needs to use a weaker set of crypto priorities for 4825 QEMU without potentially forcing the weakness onto all 4826 applications. Or conversely if one wants wants a stronger 4827 default for QEMU than for all other applications, they can do 4828 this through this parameter. Its format is a gnutls priority 4829 string as described at 4830 https://gnutls.org/manual/html_node/Priority-Strings.html. 4831 4832 An example of use of this object is to control UEFI HTTPS Boot. 4833 The tls-cipher-suites object exposes the ordered list of permitted 4834 TLS cipher suites from the host side to the guest firmware, via 4835 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4836 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4837 guest-side TLS. 4838 4839 In the following example, the priority at which the host-side policy 4840 is retrieved is given by the ``priority`` property. 4841 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4842 refer to /etc/crypto-policies/back-ends/gnutls.config. 4843 4844 .. parsed-literal:: 4845 4846 # |qemu_system| \\ 4847 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4848 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4849 4850 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4851 Interval t can't be 0, this filter batches the packet delivery: 4852 all packets arriving in a given interval on netdev netdevid are 4853 delayed until the end of the interval. Interval is in 4854 microseconds. ``status`` is optional that indicate whether the 4855 netfilter is on (enabled) or off (disabled), the default status 4856 for netfilter will be 'on'. 4857 4858 queue all\|rx\|tx is an option that can be applied to any 4859 netfilter. 4860 4861 ``all``: the filter is attached both to the receive and the 4862 transmit queue of the netdev (default). 4863 4864 ``rx``: the filter is attached to the receive queue of the 4865 netdev, where it will receive packets sent to the netdev. 4866 4867 ``tx``: the filter is attached to the transmit queue of the 4868 netdev, where it will receive packets sent by the netdev. 4869 4870 position head\|tail\|id=<id> is an option to specify where the 4871 filter should be inserted in the filter list. It can be applied 4872 to any netfilter. 4873 4874 ``head``: the filter is inserted at the head of the filter list, 4875 before any existing filters. 4876 4877 ``tail``: the filter is inserted at the tail of the filter list, 4878 behind any existing filters (default). 4879 4880 ``id=<id>``: the filter is inserted before or behind the filter 4881 specified by <id>, see the insert option below. 4882 4883 insert behind\|before is an option to specify where to insert 4884 the new filter relative to the one specified with 4885 position=id=<id>. It can be applied to any netfilter. 4886 4887 ``before``: insert before the specified filter. 4888 4889 ``behind``: insert behind the specified filter (default). 4890 4891 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4892 filter-mirror on netdev netdevid,mirror net packet to 4893 chardevchardevid, if it has the vnet\_hdr\_support flag, 4894 filter-mirror will mirror packet with vnet\_hdr\_len. 4895 4896 ``-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]`` 4897 filter-redirector on netdev netdevid,redirect filter's net 4898 packet to chardev chardevid,and redirect indev's packet to 4899 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4900 will redirect packet with vnet\_hdr\_len. Create a 4901 filter-redirector we need to differ outdev id from indev id, id 4902 can not be the same. we can just use indev or outdev, but at 4903 least one of indev or outdev need to be specified. 4904 4905 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4906 Filter-rewriter is a part of COLO project.It will rewrite tcp 4907 packet to secondary from primary to keep secondary tcp 4908 connection,and rewrite tcp packet to primary from secondary make 4909 tcp packet can be handled by client.if it has the 4910 vnet\_hdr\_support flag, we can parse packet with vnet header. 4911 4912 usage: colo secondary: -object 4913 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4914 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4915 filter-rewriter,id=rew0,netdev=hn0,queue=all 4916 4917 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4918 Dump the network traffic on netdev dev to the file specified by 4919 filename. At most len bytes (64k by default) per packet are 4920 stored. The file format is libpcap, so it can be analyzed with 4921 tools such as tcpdump or Wireshark. 4922 4923 ``-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}]`` 4924 Colo-compare gets packet from primary\_in chardevid and 4925 secondary\_in, then compare whether the payload of primary packet 4926 and secondary packet are the same. If same, it will output 4927 primary packet to out\_dev, else it will notify COLO-framework to do 4928 checkpoint and send primary packet to out\_dev. In order to 4929 improve efficiency, we need to put the task of comparison in 4930 another iothread. If it has the vnet\_hdr\_support flag, 4931 colo compare will send/recv packet with vnet\_hdr\_len. 4932 The compare\_timeout=@var{ms} determines the maximum time of the 4933 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4934 is to set the period of scanning expired primary node network packets. 4935 The max\_queue\_size=@var{size} is to set the max compare queue 4936 size depend on user environment. 4937 If user want to use Xen COLO, need to add the notify\_dev to 4938 notify Xen colo-frame to do checkpoint. 4939 4940 COLO-compare must be used with the help of filter-mirror, 4941 filter-redirector and filter-rewriter. 4942 4943 :: 4944 4945 KVM COLO 4946 4947 primary: 4948 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4949 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4950 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4951 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4952 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4953 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4954 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4955 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4956 -object iothread,id=iothread1 4957 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4958 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4959 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4960 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4961 4962 secondary: 4963 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4964 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4965 -chardev socket,id=red0,host=3.3.3.3,port=9003 4966 -chardev socket,id=red1,host=3.3.3.3,port=9004 4967 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4968 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4969 4970 4971 Xen COLO 4972 4973 primary: 4974 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4975 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4976 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4977 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4978 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4979 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4980 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4981 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4982 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 4983 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4984 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4985 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4986 -object iothread,id=iothread1 4987 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4988 4989 secondary: 4990 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4991 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4992 -chardev socket,id=red0,host=3.3.3.3,port=9003 4993 -chardev socket,id=red1,host=3.3.3.3,port=9004 4994 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4995 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4996 4997 If you want to know the detail of above command line, you can 4998 read the colo-compare git log. 4999 5000 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5001 Creates a cryptodev backend which executes crypto opreation from 5002 the QEMU cipher APIS. The id parameter is a unique ID that will 5003 be used to reference this cryptodev backend from the 5004 ``virtio-crypto`` device. The queues parameter is optional, 5005 which specify the queue number of cryptodev backend, the default 5006 of queues is 1. 5007 5008 .. parsed-literal:: 5009 5010 # |qemu_system| \\ 5011 [...] \\ 5012 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5013 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5014 [...] 5015 5016 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5017 Creates a vhost-user cryptodev backend, backed by a chardev 5018 chardevid. The id parameter is a unique ID that will be used to 5019 reference this cryptodev backend from the ``virtio-crypto`` 5020 device. The chardev should be a unix domain socket backed one. 5021 The vhost-user uses a specifically defined protocol to pass 5022 vhost ioctl replacement messages to an application on the other 5023 end of the socket. The queues parameter is optional, which 5024 specify the queue number of cryptodev backend for multiqueue 5025 vhost-user, the default of queues is 1. 5026 5027 .. parsed-literal:: 5028 5029 # |qemu_system| \\ 5030 [...] \\ 5031 -chardev socket,id=chardev0,path=/path/to/socket \\ 5032 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5033 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5034 [...] 5035 5036 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5037 \ 5038 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5039 Defines a secret to store a password, encryption key, or some 5040 other sensitive data. The sensitive data can either be passed 5041 directly via the data parameter, or indirectly via the file 5042 parameter. Using the data parameter is insecure unless the 5043 sensitive data is encrypted. 5044 5045 The sensitive data can be provided in raw format (the default), 5046 or base64. When encoded as JSON, the raw format only supports 5047 valid UTF-8 characters, so base64 is recommended for sending 5048 binary data. QEMU will convert from which ever format is 5049 provided to the format it needs internally. eg, an RBD password 5050 can be provided in raw format, even though it will be base64 5051 encoded when passed onto the RBD sever. 5052 5053 For added protection, it is possible to encrypt the data 5054 associated with a secret using the AES-256-CBC cipher. Use of 5055 encryption is indicated by providing the keyid and iv 5056 parameters. The keyid parameter provides the ID of a previously 5057 defined secret that contains the AES-256 decryption key. This 5058 key should be 32-bytes long and be base64 encoded. The iv 5059 parameter provides the random initialization vector used for 5060 encryption of this particular secret and should be a base64 5061 encrypted string of the 16-byte IV. 5062 5063 The simplest (insecure) usage is to provide the secret inline 5064 5065 .. parsed-literal:: 5066 5067 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5068 5069 The simplest secure usage is to provide the secret via a file 5070 5071 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5072 secret,id=sec0,file=mypasswd.txt,format=raw 5073 5074 For greater security, AES-256-CBC should be used. To illustrate 5075 usage, consider the openssl command line tool which can encrypt 5076 the data. Note that when encrypting, the plaintext must be 5077 padded to the cipher block size (32 bytes) using the standard 5078 PKCS#5/6 compatible padding algorithm. 5079 5080 First a master key needs to be created in base64 encoding: 5081 5082 :: 5083 5084 # openssl rand -base64 32 > key.b64 5085 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5086 5087 Each secret to be encrypted needs to have a random 5088 initialization vector generated. These do not need to be kept 5089 secret 5090 5091 :: 5092 5093 # openssl rand -base64 16 > iv.b64 5094 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5095 5096 The secret to be defined can now be encrypted, in this case 5097 we're telling openssl to base64 encode the result, but it could 5098 be left as raw bytes if desired. 5099 5100 :: 5101 5102 # SECRET=$(printf "letmein" | 5103 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5104 5105 When launching QEMU, create a master secret pointing to 5106 ``key.b64`` and specify that to be used to decrypt the user 5107 password. Pass the contents of ``iv.b64`` to the second secret 5108 5109 .. parsed-literal:: 5110 5111 # |qemu_system| \\ 5112 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5113 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5114 data=$SECRET,iv=$(<iv.b64) 5115 5116 ``-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]`` 5117 Create a Secure Encrypted Virtualization (SEV) guest object, 5118 which can be used to provide the guest memory encryption support 5119 on AMD processors. 5120 5121 When memory encryption is enabled, one of the physical address 5122 bit (aka the C-bit) is utilized to mark if a memory page is 5123 protected. The ``cbitpos`` is used to provide the C-bit 5124 position. The C-bit position is Host family dependent hence user 5125 must provide this value. On EPYC, the value should be 47. 5126 5127 When memory encryption is enabled, we loose certain bits in 5128 physical address space. The ``reduced-phys-bits`` is used to 5129 provide the number of bits we loose in physical address space. 5130 Similar to C-bit, the value is Host family dependent. On EPYC, 5131 the value should be 5. 5132 5133 The ``sev-device`` provides the device file to use for 5134 communicating with the SEV firmware running inside AMD Secure 5135 Processor. The default device is '/dev/sev'. If hardware 5136 supports memory encryption then /dev/sev devices are created by 5137 CCP driver. 5138 5139 The ``policy`` provides the guest policy to be enforced by the 5140 SEV firmware and restrict what configuration and operational 5141 commands can be performed on this guest by the hypervisor. The 5142 policy should be provided by the guest owner and is bound to the 5143 guest and cannot be changed throughout the lifetime of the 5144 guest. The default is 0. 5145 5146 If guest ``policy`` allows sharing the key with another SEV 5147 guest then ``handle`` can be use to provide handle of the guest 5148 from which to share the key. 5149 5150 The ``dh-cert-file`` and ``session-file`` provides the guest 5151 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5152 and session parameters are used for establishing a cryptographic 5153 session with the guest owner to negotiate keys used for 5154 attestation. The file must be encoded in base64. 5155 5156 e.g to launch a SEV guest 5157 5158 .. parsed-literal:: 5159 5160 # |qemu_system_x86| \\ 5161 ...... \\ 5162 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5163 -machine ...,memory-encryption=sev0 \\ 5164 ..... 5165 5166 ``-object authz-simple,id=id,identity=string`` 5167 Create an authorization object that will control access to 5168 network services. 5169 5170 The ``identity`` parameter is identifies the user and its format 5171 depends on the network service that authorization object is 5172 associated with. For authorizing based on TLS x509 certificates, 5173 the identity must be the x509 distinguished name. Note that care 5174 must be taken to escape any commas in the distinguished name. 5175 5176 An example authorization object to validate a x509 distinguished 5177 name would look like: 5178 5179 .. parsed-literal:: 5180 5181 # |qemu_system| \\ 5182 ... \\ 5183 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5184 ... 5185 5186 Note the use of quotes due to the x509 distinguished name 5187 containing whitespace, and escaping of ','. 5188 5189 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5190 Create an authorization object that will control access to 5191 network services. 5192 5193 The ``filename`` parameter is the fully qualified path to a file 5194 containing the access control list rules in JSON format. 5195 5196 An example set of rules that match against SASL usernames might 5197 look like: 5198 5199 :: 5200 5201 { 5202 "rules": [ 5203 { "match": "fred", "policy": "allow", "format": "exact" }, 5204 { "match": "bob", "policy": "allow", "format": "exact" }, 5205 { "match": "danb", "policy": "deny", "format": "glob" }, 5206 { "match": "dan*", "policy": "allow", "format": "exact" }, 5207 ], 5208 "policy": "deny" 5209 } 5210 5211 When checking access the object will iterate over all the rules 5212 and the first rule to match will have its ``policy`` value 5213 returned as the result. If no rules match, then the default 5214 ``policy`` value is returned. 5215 5216 The rules can either be an exact string match, or they can use 5217 the simple UNIX glob pattern matching to allow wildcards to be 5218 used. 5219 5220 If ``refresh`` is set to true the file will be monitored and 5221 automatically reloaded whenever its content changes. 5222 5223 As with the ``authz-simple`` object, the format of the identity 5224 strings being matched depends on the network service, but is 5225 usually a TLS x509 distinguished name, or a SASL username. 5226 5227 An example authorization object to validate a SASL username 5228 would look like: 5229 5230 .. parsed-literal:: 5231 5232 # |qemu_system| \\ 5233 ... \\ 5234 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5235 ... 5236 5237 ``-object authz-pam,id=id,service=string`` 5238 Create an authorization object that will control access to 5239 network services. 5240 5241 The ``service`` parameter provides the name of a PAM service to 5242 use for authorization. It requires that a file 5243 ``/etc/pam.d/service`` exist to provide the configuration for 5244 the ``account`` subsystem. 5245 5246 An example authorization object to validate a TLS x509 5247 distinguished name would look like: 5248 5249 .. parsed-literal:: 5250 5251 # |qemu_system| \\ 5252 ... \\ 5253 -object authz-pam,id=auth0,service=qemu-vnc \\ 5254 ... 5255 5256 There would then be a corresponding config file for PAM at 5257 ``/etc/pam.d/qemu-vnc`` that contains: 5258 5259 :: 5260 5261 account requisite pam_listfile.so item=user sense=allow \ 5262 file=/etc/qemu/vnc.allow 5263 5264 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5265 of x509 distingished names that are permitted access 5266 5267 :: 5268 5269 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5270 5271 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5272 Creates a dedicated event loop thread that devices can be 5273 assigned to. This is known as an IOThread. By default device 5274 emulation happens in vCPU threads or the main event loop thread. 5275 This can become a scalability bottleneck. IOThreads allow device 5276 emulation and I/O to run on other host CPUs. 5277 5278 The ``id`` parameter is a unique ID that will be used to 5279 reference this IOThread from ``-device ...,iothread=id``. 5280 Multiple devices can be assigned to an IOThread. Note that not 5281 all devices support an ``iothread`` parameter. 5282 5283 The ``query-iothreads`` QMP command lists IOThreads and reports 5284 their thread IDs so that the user can configure host CPU 5285 pinning/affinity. 5286 5287 IOThreads use an adaptive polling algorithm to reduce event loop 5288 latency. Instead of entering a blocking system call to monitor 5289 file descriptors and then pay the cost of being woken up when an 5290 event occurs, the polling algorithm spins waiting for events for 5291 a short time. The algorithm's default parameters are suitable 5292 for many cases but can be adjusted based on knowledge of the 5293 workload and/or host device latency. 5294 5295 The ``poll-max-ns`` parameter is the maximum number of 5296 nanoseconds to busy wait for events. Polling can be disabled by 5297 setting this value to 0. 5298 5299 The ``poll-grow`` parameter is the multiplier used to increase 5300 the polling time when the algorithm detects it is missing events 5301 due to not polling long enough. 5302 5303 The ``poll-shrink`` parameter is the divisor used to decrease 5304 the polling time when the algorithm detects it is spending too 5305 long polling without encountering events. 5306 5307 The polling parameters can be modified at run-time using the 5308 ``qom-set`` command (where ``iothread1`` is the IOThread's 5309 ``id``): 5310 5311 :: 5312 5313 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5314ERST 5315 5316 5317HXCOMM This is the last statement. Insert new options before this line! 5318 5319#undef DEF 5320#undef DEFHEADING 5321#undef ARCHHEADING 5322
