1HXCOMM Use DEFHEADING() to define headings in both help text and texi 2HXCOMM Text between STEXI and ETEXI are copied to texi 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 texi and C 8 9DEFHEADING(Standard options:) 10STEXI 11@table @option 12ETEXI 13 14DEF("help", 0, QEMU_OPTION_h, 15 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 16STEXI 17@item -h 18@findex -h 19Display help and exit 20ETEXI 21 22DEF("version", 0, QEMU_OPTION_version, 23 "-version display version information and exit\n", QEMU_ARCH_ALL) 24STEXI 25@item -version 26@findex -version 27Display version information and exit 28ETEXI 29 30DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 31 "-machine [type=]name[,prop[=value][,...]]\n" 32 " selects emulated machine ('-machine help' for list)\n" 33 " property accel=accel1[:accel2[:...]] selects accelerator\n" 34 " supported accelerators are kvm, xen, hax, hvf, whpx or tcg (default: tcg)\n" 35 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 36 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 37 " mem-merge=on|off controls memory merge support (default: on)\n" 38 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 39 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 40 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 41 " nvdimm=on|off controls NVDIMM support (default=off)\n" 42 " enforce-config-section=on|off enforce configuration section migration (default=off)\n" 43 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 44 " hmat=on|off controls ACPI HMAT support (default=off)\n", 45 QEMU_ARCH_ALL) 46STEXI 47@item -machine [type=]@var{name}[,prop=@var{value}[,...]] 48@findex -machine 49Select the emulated machine by @var{name}. Use @code{-machine help} to list 50available machines. 51 52For architectures which aim to support live migration compatibility 53across releases, each release will introduce a new versioned machine 54type. For example, the 2.8.0 release introduced machine types 55``pc-i440fx-2.8'' and ``pc-q35-2.8'' for the x86_64/i686 architectures. 56 57To allow live migration of guests from QEMU version 2.8.0, to QEMU 58version 2.9.0, the 2.9.0 version must support the ``pc-i440fx-2.8'' 59and ``pc-q35-2.8'' machines too. To allow users live migrating VMs 60to skip multiple intermediate releases when upgrading, new releases 61of QEMU will support machine types from many previous versions. 62 63Supported machine properties are: 64@table @option 65@item accel=@var{accels1}[:@var{accels2}[:...]] 66This is used to enable an accelerator. Depending on the target architecture, 67kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If there is 68more than one accelerator specified, the next one is used if the previous one 69fails to initialize. 70@item vmport=on|off|auto 71Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the 72value based on accel. For accel=xen the default is off otherwise the default 73is on. 74@item dump-guest-core=on|off 75Include guest memory in a core dump. The default is on. 76@item mem-merge=on|off 77Enables or disables memory merge support. This feature, when supported by 78the host, de-duplicates identical memory pages among VMs instances 79(enabled by default). 80@item aes-key-wrap=on|off 81Enables or disables AES key wrapping support on s390-ccw hosts. This feature 82controls whether AES wrapping keys will be created to allow 83execution of AES cryptographic functions. The default is on. 84@item dea-key-wrap=on|off 85Enables or disables DEA key wrapping support on s390-ccw hosts. This feature 86controls whether DEA wrapping keys will be created to allow 87execution of DEA cryptographic functions. The default is on. 88@item nvdimm=on|off 89Enables or disables NVDIMM support. The default is off. 90@item enforce-config-section=on|off 91If @option{enforce-config-section} is set to @var{on}, force migration 92code to send configuration section even if the machine-type sets the 93@option{migration.send-configuration} property to @var{off}. 94NOTE: this parameter is deprecated. Please use @option{-global} 95@option{migration.send-configuration}=@var{on|off} instead. 96@item memory-encryption=@var{} 97Memory encryption object to use. The default is none. 98@item hmat=on|off 99Enables or disables ACPI Heterogeneous Memory Attribute Table (HMAT) support. 100The default is off. 101@end table 102ETEXI 103 104HXCOMM Deprecated by -machine 105DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL) 106 107DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 108 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 109STEXI 110@item -cpu @var{model} 111@findex -cpu 112Select CPU model (@code{-cpu help} for list and additional feature selection) 113ETEXI 114 115DEF("accel", HAS_ARG, QEMU_OPTION_accel, 116 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 117 " select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n" 118 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 119 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 120 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 121 " tb-size=n (TCG translation block cache size)\n" 122 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 123STEXI 124@item -accel @var{name}[,prop=@var{value}[,...]] 125@findex -accel 126This is used to enable an accelerator. Depending on the target architecture, 127kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If there is 128more than one accelerator specified, the next one is used if the previous one 129fails to initialize. 130@table @option 131@item igd-passthru=on|off 132When Xen is in use, this option controls whether Intel integrated graphics 133devices can be passed through to the guest (default=off) 134@item kernel-irqchip=on|off|split 135Controls KVM in-kernel irqchip support. The default is full acceleration of the 136interrupt controllers. On x86, split irqchip reduces the kernel attack 137surface, at a performance cost for non-MSI interrupts. Disabling the in-kernel 138irqchip completely is not recommended except for debugging purposes. 139@item kvm-shadow-mem=size 140Defines the size of the KVM shadow MMU. 141@item tb-size=@var{n} 142Controls the size (in MiB) of the TCG translation block cache. 143@item thread=single|multi 144Controls number of TCG threads. When the TCG is multi-threaded there will be one 145thread per vCPU therefor taking advantage of additional host cores. The default 146is to enable multi-threading where both the back-end and front-ends support it and 147no incompatible TCG features have been enabled (e.g. icount/replay). 148@end table 149ETEXI 150 151DEF("smp", HAS_ARG, QEMU_OPTION_smp, 152 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 153 " set the number of CPUs to 'n' [default=1]\n" 154 " maxcpus= maximum number of total cpus, including\n" 155 " offline CPUs for hotplug, etc\n" 156 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 157 " threads= number of threads on one CPU core\n" 158 " dies= number of CPU dies on one socket (for PC only)\n" 159 " sockets= number of discrete sockets in the system\n", 160 QEMU_ARCH_ALL) 161STEXI 162@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,dies=dies][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}] 163@findex -smp 164Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255 165CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs 166to 4. 167For the PC target, the number of @var{cores} per die, the number of @var{threads} 168per cores, the number of @var{dies} per packages and the total number of 169@var{sockets} can be specified. Missing values will be computed. 170If any on the three values is given, the total number of CPUs @var{n} can be omitted. 171@var{maxcpus} specifies the maximum number of hotpluggable CPUs. 172ETEXI 173 174DEF("numa", HAS_ARG, QEMU_OPTION_numa, 175 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 176 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 177 "-numa dist,src=source,dst=destination,val=distance\n" 178 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 179 "-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" 180 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 181 QEMU_ARCH_ALL) 182STEXI 183@item -numa node[,mem=@var{size}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}][,initiator=@var{initiator}] 184@itemx -numa node[,memdev=@var{id}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}][,initiator=@var{initiator}] 185@itemx -numa dist,src=@var{source},dst=@var{destination},val=@var{distance} 186@itemx -numa cpu,node-id=@var{node}[,socket-id=@var{x}][,core-id=@var{y}][,thread-id=@var{z}] 187@itemx -numa hmat-lb,initiator=@var{node},target=@var{node},hierarchy=@var{hierarchy},data-type=@var{tpye}[,latency=@var{lat}][,bandwidth=@var{bw}] 188@itemx -numa hmat-cache,node-id=@var{node},size=@var{size},level=@var{level}[,associativity=@var{str}][,policy=@var{str}][,line=@var{size}] 189@findex -numa 190Define a NUMA node and assign RAM and VCPUs to it. 191Set the NUMA distance from a source node to a destination node. 192Set the ACPI Heterogeneous Memory Attributes for the given nodes. 193 194Legacy VCPU assignment uses @samp{cpus} option where 195@var{firstcpu} and @var{lastcpu} are CPU indexes. Each 196@samp{cpus} option represent a contiguous range of CPU indexes 197(or a single VCPU if @var{lastcpu} is omitted). A non-contiguous 198set of VCPUs can be represented by providing multiple @samp{cpus} 199options. If @samp{cpus} is omitted on all nodes, VCPUs are automatically 200split between them. 201 202For example, the following option assigns VCPUs 0, 1, 2 and 5 to 203a NUMA node: 204@example 205-numa node,cpus=0-2,cpus=5 206@end example 207 208@samp{cpu} option is a new alternative to @samp{cpus} option 209which uses @samp{socket-id|core-id|thread-id} properties to assign 210CPU objects to a @var{node} using topology layout properties of CPU. 211The set of properties is machine specific, and depends on used 212machine type/@samp{smp} options. It could be queried with 213@samp{hotpluggable-cpus} monitor command. 214@samp{node-id} property specifies @var{node} to which CPU object 215will be assigned, it's required for @var{node} to be declared 216with @samp{node} option before it's used with @samp{cpu} option. 217 218For example: 219@example 220-M pc \ 221-smp 1,sockets=2,maxcpus=2 \ 222-numa node,nodeid=0 -numa node,nodeid=1 \ 223-numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 224@end example 225 226@samp{mem} assigns a given RAM amount to a node. @samp{memdev} 227assigns RAM from a given memory backend device to a node. If 228@samp{mem} and @samp{memdev} are omitted in all nodes, RAM is 229split equally between them. 230 231@samp{mem} and @samp{memdev} are mutually exclusive. Furthermore, 232if one node uses @samp{memdev}, all of them have to use it. 233 234@samp{initiator} is an additional option that points to an @var{initiator} 235NUMA node that has best performance (the lowest latency or largest bandwidth) 236to this NUMA @var{node}. Note that this option can be set only when 237the machine property 'hmat' is set to 'on'. 238 239Following example creates a machine with 2 NUMA nodes, node 0 has CPU. 240node 1 has only memory, and its initiator is node 0. Note that because 241node 0 has CPU, by default the initiator of node 0 is itself and must be 242itself. 243@example 244-machine hmat=on \ 245-m 2G,slots=2,maxmem=4G \ 246-object memory-backend-ram,size=1G,id=m0 \ 247-object memory-backend-ram,size=1G,id=m1 \ 248-numa node,nodeid=0,memdev=m0 \ 249-numa node,nodeid=1,memdev=m1,initiator=0 \ 250-smp 2,sockets=2,maxcpus=2 \ 251-numa cpu,node-id=0,socket-id=0 \ 252-numa cpu,node-id=0,socket-id=1 253@end example 254 255@var{source} and @var{destination} are NUMA node IDs. 256@var{distance} is the NUMA distance from @var{source} to @var{destination}. 257The distance from a node to itself is always 10. If any pair of nodes is 258given a distance, then all pairs must be given distances. Although, when 259distances are only given in one direction for each pair of nodes, then 260the distances in the opposite directions are assumed to be the same. If, 261however, an asymmetrical pair of distances is given for even one node 262pair, then all node pairs must be provided distance values for both 263directions, even when they are symmetrical. When a node is unreachable 264from another node, set the pair's distance to 255. 265 266Note that the -@option{numa} option doesn't allocate any of the 267specified resources, it just assigns existing resources to NUMA 268nodes. This means that one still has to use the @option{-m}, 269@option{-smp} options to allocate RAM and VCPUs respectively. 270 271Use @samp{hmat-lb} to set System Locality Latency and Bandwidth Information 272between initiator and target NUMA nodes in ACPI Heterogeneous Attribute Memory Table (HMAT). 273Initiator NUMA node can create memory requests, usually it has one or more processors. 274Target NUMA node contains addressable memory. 275 276In @samp{hmat-lb} option, @var{node} are NUMA node IDs. @var{hierarchy} is the memory 277hierarchy of the target NUMA node: if @var{hierarchy} is 'memory', the structure 278represents the memory performance; if @var{hierarchy} is 'first-level|second-level|third-level', 279this structure represents aggregated performance of memory side caches for each domain. 280@var{type} of 'data-type' is type of data represented by this structure instance: 281if 'hierarchy' is 'memory', 'data-type' is 'access|read|write' latency or 'access|read|write' 282bandwidth of the target memory; if 'hierarchy' is 'first-level|second-level|third-level', 283'data-type' is 'access|read|write' hit latency or 'access|read|write' hit bandwidth of the 284target memory side cache. 285 286@var{lat} is latency value in nanoseconds. @var{bw} is bandwidth value, 287the possible value and units are NUM[M|G|T], mean that the bandwidth value are 288NUM byte per second (or MB/s, GB/s or TB/s depending on used suffix). 289Note that if latency or bandwidth value is 0, means the corresponding latency or 290bandwidth information is not provided. 291 292In @samp{hmat-cache} option, @var{node-id} is the NUMA-id of the memory belongs. 293@var{size} is the size of memory side cache in bytes. @var{level} is the cache 294level described in this structure, note that the cache level 0 should not be used 295with @samp{hmat-cache} option. @var{associativity} is the cache associativity, 296the possible value is 'none/direct(direct-mapped)/complex(complex cache indexing)'. 297@var{policy} is the write policy. @var{line} is the cache Line size in bytes. 298 299For example, the following options describe 2 NUMA nodes. Node 0 has 2 cpus and 300a ram, node 1 has only a ram. The processors in node 0 access memory in node 3010 with access-latency 5 nanoseconds, access-bandwidth is 200 MB/s; 302The processors in NUMA node 0 access memory in NUMA node 1 with access-latency 10 303nanoseconds, access-bandwidth is 100 MB/s. 304And for memory side cache information, NUMA node 0 and 1 both have 1 level memory 305cache, size is 10KB, policy is write-back, the cache Line size is 8 bytes: 306@example 307-machine hmat=on \ 308-m 2G \ 309-object memory-backend-ram,size=1G,id=m0 \ 310-object memory-backend-ram,size=1G,id=m1 \ 311-smp 2 \ 312-numa node,nodeid=0,memdev=m0 \ 313-numa node,nodeid=1,memdev=m1,initiator=0 \ 314-numa cpu,node-id=0,socket-id=0 \ 315-numa cpu,node-id=0,socket-id=1 \ 316-numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 317-numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 318-numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 319-numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 320-numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 321-numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 322@end example 323 324ETEXI 325 326DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 327 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 328 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 329STEXI 330@item -add-fd fd=@var{fd},set=@var{set}[,opaque=@var{opaque}] 331@findex -add-fd 332 333Add a file descriptor to an fd set. Valid options are: 334 335@table @option 336@item fd=@var{fd} 337This option defines the file descriptor of which a duplicate is added to fd set. 338The file descriptor cannot be stdin, stdout, or stderr. 339@item set=@var{set} 340This option defines the ID of the fd set to add the file descriptor to. 341@item opaque=@var{opaque} 342This option defines a free-form string that can be used to describe @var{fd}. 343@end table 344 345You can open an image using pre-opened file descriptors from an fd set: 346@example 347@value{qemu_system} \ 348 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \ 349 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \ 350 -drive file=/dev/fdset/2,index=0,media=disk 351@end example 352ETEXI 353 354DEF("set", HAS_ARG, QEMU_OPTION_set, 355 "-set group.id.arg=value\n" 356 " set <arg> parameter for item <id> of type <group>\n" 357 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 358STEXI 359@item -set @var{group}.@var{id}.@var{arg}=@var{value} 360@findex -set 361Set parameter @var{arg} for item @var{id} of type @var{group} 362ETEXI 363 364DEF("global", HAS_ARG, QEMU_OPTION_global, 365 "-global driver.property=value\n" 366 "-global driver=driver,property=property,value=value\n" 367 " set a global default for a driver property\n", 368 QEMU_ARCH_ALL) 369STEXI 370@item -global @var{driver}.@var{prop}=@var{value} 371@itemx -global driver=@var{driver},property=@var{property},value=@var{value} 372@findex -global 373Set default value of @var{driver}'s property @var{prop} to @var{value}, e.g.: 374 375@example 376@value{qemu_system_x86} -global ide-hd.physical_block_size=4096 disk-image.img 377@end example 378 379In particular, you can use this to set driver properties for devices which are 380created automatically by the machine model. To create a device which is not 381created automatically and set properties on it, use -@option{device}. 382 383-global @var{driver}.@var{prop}=@var{value} is shorthand for -global 384driver=@var{driver},property=@var{prop},value=@var{value}. The 385longhand syntax works even when @var{driver} contains a dot. 386ETEXI 387 388DEF("boot", HAS_ARG, QEMU_OPTION_boot, 389 "-boot [order=drives][,once=drives][,menu=on|off]\n" 390 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 391 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 392 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 393 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 394 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 395 QEMU_ARCH_ALL) 396STEXI 397@item -boot [order=@var{drives}][,once=@var{drives}][,menu=on|off][,splash=@var{sp_name}][,splash-time=@var{sp_time}][,reboot-timeout=@var{rb_timeout}][,strict=on|off] 398@findex -boot 399Specify boot order @var{drives} as a string of drive letters. Valid 400drive letters depend on the target architecture. The x86 PC uses: a, b 401(floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot 402from network adapter 1-4), hard disk boot is the default. To apply a 403particular boot order only on the first startup, specify it via 404@option{once}. Note that the @option{order} or @option{once} parameter 405should not be used together with the @option{bootindex} property of 406devices, since the firmware implementations normally do not support both 407at the same time. 408 409Interactive boot menus/prompts can be enabled via @option{menu=on} as far 410as firmware/BIOS supports them. The default is non-interactive boot. 411 412A splash picture could be passed to bios, enabling user to show it as logo, 413when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS 414supports them. Currently Seabios for X86 system support it. 415limitation: The splash file could be a jpeg file or a BMP file in 24 BPP 416format(true color). The resolution should be supported by the SVGA mode, so 417the recommended is 320x240, 640x480, 800x640. 418 419A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms 420when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not 421reboot, qemu passes '-1' to bios by default. Currently Seabios for X86 422system support it. 423 424Do strict boot via @option{strict=on} as far as firmware/BIOS 425supports it. This only effects when boot priority is changed by 426bootindex options. The default is non-strict boot. 427 428@example 429# try to boot from network first, then from hard disk 430@value{qemu_system_x86} -boot order=nc 431# boot from CD-ROM first, switch back to default order after reboot 432@value{qemu_system_x86} -boot once=d 433# boot with a splash picture for 5 seconds. 434@value{qemu_system_x86} -boot menu=on,splash=/root/boot.bmp,splash-time=5000 435@end example 436 437Note: The legacy format '-boot @var{drives}' is still supported but its 438use is discouraged as it may be removed from future versions. 439ETEXI 440 441DEF("m", HAS_ARG, QEMU_OPTION_m, 442 "-m [size=]megs[,slots=n,maxmem=size]\n" 443 " configure guest RAM\n" 444 " size: initial amount of guest memory\n" 445 " slots: number of hotplug slots (default: none)\n" 446 " maxmem: maximum amount of guest memory (default: none)\n" 447 "NOTE: Some architectures might enforce a specific granularity\n", 448 QEMU_ARCH_ALL) 449STEXI 450@item -m [size=]@var{megs}[,slots=n,maxmem=size] 451@findex -m 452Sets guest startup RAM size to @var{megs} megabytes. Default is 128 MiB. 453Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in 454megabytes or gigabytes respectively. Optional pair @var{slots}, @var{maxmem} 455could be used to set amount of hotpluggable memory slots and maximum amount of 456memory. Note that @var{maxmem} must be aligned to the page size. 457 458For example, the following command-line sets the guest startup RAM size to 4591GB, creates 3 slots to hotplug additional memory and sets the maximum 460memory the guest can reach to 4GB: 461 462@example 463@value{qemu_system} -m 1G,slots=3,maxmem=4G 464@end example 465 466If @var{slots} and @var{maxmem} are not specified, memory hotplug won't 467be enabled and the guest startup RAM will never increase. 468ETEXI 469 470DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 471 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 472STEXI 473@item -mem-path @var{path} 474@findex -mem-path 475Allocate guest RAM from a temporarily created file in @var{path}. 476ETEXI 477 478DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 479 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 480 QEMU_ARCH_ALL) 481STEXI 482@item -mem-prealloc 483@findex -mem-prealloc 484Preallocate memory when using -mem-path. 485ETEXI 486 487DEF("k", HAS_ARG, QEMU_OPTION_k, 488 "-k language use keyboard layout (for example 'fr' for French)\n", 489 QEMU_ARCH_ALL) 490STEXI 491@item -k @var{language} 492@findex -k 493Use keyboard layout @var{language} (for example @code{fr} for 494French). This option is only needed where it is not easy to get raw PC 495keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses 496display). You don't normally need to use it on PC/Linux or PC/Windows 497hosts. 498 499The available layouts are: 500@example 501ar de-ch es fo fr-ca hu ja mk no pt-br sv 502da en-gb et fr fr-ch is lt nl pl ru th 503de en-us fi fr-be hr it lv nl-be pt sl tr 504@end example 505 506The default is @code{en-us}. 507ETEXI 508 509 510HXCOMM Deprecated by -audiodev 511DEF("audio-help", 0, QEMU_OPTION_audio_help, 512 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 513 QEMU_ARCH_ALL) 514STEXI 515@item -audio-help 516@findex -audio-help 517Will show the -audiodev equivalent of the currently specified 518(deprecated) environment variables. 519ETEXI 520 521DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 522 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 523 " specifies the audio backend to use\n" 524 " id= identifier of the backend\n" 525 " timer-period= timer period in microseconds\n" 526 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 527 " in|out.fixed-settings= use fixed settings for host audio\n" 528 " in|out.frequency= frequency to use with fixed settings\n" 529 " in|out.channels= number of channels to use with fixed settings\n" 530 " in|out.format= sample format to use with fixed settings\n" 531 " valid values: s8, s16, s32, u8, u16, u32\n" 532 " in|out.voices= number of voices to use\n" 533 " in|out.buffer-length= length of buffer in microseconds\n" 534 "-audiodev none,id=id,[,prop[=value][,...]]\n" 535 " dummy driver that discards all output\n" 536#ifdef CONFIG_AUDIO_ALSA 537 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 538 " in|out.dev= name of the audio device to use\n" 539 " in|out.period-length= length of period in microseconds\n" 540 " in|out.try-poll= attempt to use poll mode\n" 541 " threshold= threshold (in microseconds) when playback starts\n" 542#endif 543#ifdef CONFIG_AUDIO_COREAUDIO 544 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 545 " in|out.buffer-count= number of buffers\n" 546#endif 547#ifdef CONFIG_AUDIO_DSOUND 548 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 549 " latency= add extra latency to playback in microseconds\n" 550#endif 551#ifdef CONFIG_AUDIO_OSS 552 "-audiodev oss,id=id[,prop[=value][,...]]\n" 553 " in|out.dev= path of the audio device to use\n" 554 " in|out.buffer-count= number of buffers\n" 555 " in|out.try-poll= attempt to use poll mode\n" 556 " try-mmap= try using memory mapped access\n" 557 " exclusive= open device in exclusive mode\n" 558 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 559#endif 560#ifdef CONFIG_AUDIO_PA 561 "-audiodev pa,id=id[,prop[=value][,...]]\n" 562 " server= PulseAudio server address\n" 563 " in|out.name= source/sink device name\n" 564 " in|out.latency= desired latency in microseconds\n" 565#endif 566#ifdef CONFIG_AUDIO_SDL 567 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 568#endif 569#ifdef CONFIG_SPICE 570 "-audiodev spice,id=id[,prop[=value][,...]]\n" 571#endif 572 "-audiodev wav,id=id[,prop[=value][,...]]\n" 573 " path= path of wav file to record\n", 574 QEMU_ARCH_ALL) 575STEXI 576@item -audiodev [driver=]@var{driver},id=@var{id}[,@var{prop}[=@var{value}][,...]] 577@findex -audiodev 578Adds a new audio backend @var{driver} identified by @var{id}. There are 579global and driver specific properties. Some values can be set 580differently for input and output, they're marked with @code{in|out.}. 581You can set the input's property with @code{in.@var{prop}} and the 582output's property with @code{out.@var{prop}}. For example: 583@example 584-audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 585-audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 586@end example 587 588NOTE: parameter validation is known to be incomplete, in many cases 589specifying an invalid option causes QEMU to print an error message and 590continue emulation without sound. 591 592Valid global options are: 593 594@table @option 595@item id=@var{identifier} 596Identifies the audio backend. 597 598@item timer-period=@var{period} 599Sets the timer @var{period} used by the audio subsystem in microseconds. 600Default is 10000 (10 ms). 601 602@item in|out.mixing-engine=on|off 603Use QEMU's mixing engine to mix all streams inside QEMU and convert 604audio formats when not supported by the backend. When off, 605@var{fixed-settings} must be off too. Note that disabling this option 606means that the selected backend must support multiple streams and the 607audio formats used by the virtual cards, otherwise you'll get no sound. 608It's not recommended to disable this option unless you want to use 5.1 609or 7.1 audio, as mixing engine only supports mono and stereo audio. 610Default is on. 611 612@item in|out.fixed-settings=on|off 613Use fixed settings for host audio. When off, it will change based on 614how the guest opens the sound card. In this case you must not specify 615@var{frequency}, @var{channels} or @var{format}. Default is on. 616 617@item in|out.frequency=@var{frequency} 618Specify the @var{frequency} to use when using @var{fixed-settings}. 619Default is 44100Hz. 620 621@item in|out.channels=@var{channels} 622Specify the number of @var{channels} to use when using 623@var{fixed-settings}. Default is 2 (stereo). 624 625@item in|out.format=@var{format} 626Specify the sample @var{format} to use when using @var{fixed-settings}. 627Valid values are: @code{s8}, @code{s16}, @code{s32}, @code{u8}, 628@code{u16}, @code{u32}. Default is @code{s16}. 629 630@item in|out.voices=@var{voices} 631Specify the number of @var{voices} to use. Default is 1. 632 633@item in|out.buffer-length=@var{usecs} 634Sets the size of the buffer in microseconds. 635 636@end table 637 638@item -audiodev none,id=@var{id}[,@var{prop}[=@var{value}][,...]] 639Creates a dummy backend that discards all outputs. This backend has no 640backend specific properties. 641 642@item -audiodev alsa,id=@var{id}[,@var{prop}[=@var{value}][,...]] 643Creates backend using the ALSA. This backend is only available on 644Linux. 645 646ALSA specific options are: 647 648@table @option 649 650@item in|out.dev=@var{device} 651Specify the ALSA @var{device} to use for input and/or output. Default 652is @code{default}. 653 654@item in|out.period-length=@var{usecs} 655Sets the period length in microseconds. 656 657@item in|out.try-poll=on|off 658Attempt to use poll mode with the device. Default is on. 659 660@item threshold=@var{threshold} 661Threshold (in microseconds) when playback starts. Default is 0. 662 663@end table 664 665@item -audiodev coreaudio,id=@var{id}[,@var{prop}[=@var{value}][,...]] 666Creates a backend using Apple's Core Audio. This backend is only 667available on Mac OS and only supports playback. 668 669Core Audio specific options are: 670 671@table @option 672 673@item in|out.buffer-count=@var{count} 674Sets the @var{count} of the buffers. 675 676@end table 677 678@item -audiodev dsound,id=@var{id}[,@var{prop}[=@var{value}][,...]] 679Creates a backend using Microsoft's DirectSound. This backend is only 680available on Windows and only supports playback. 681 682DirectSound specific options are: 683 684@table @option 685 686@item latency=@var{usecs} 687Add extra @var{usecs} microseconds latency to playback. Default is 68810000 (10 ms). 689 690@end table 691 692@item -audiodev oss,id=@var{id}[,@var{prop}[=@var{value}][,...]] 693Creates a backend using OSS. This backend is available on most 694Unix-like systems. 695 696OSS specific options are: 697 698@table @option 699 700@item in|out.dev=@var{device} 701Specify the file name of the OSS @var{device} to use. Default is 702@code{/dev/dsp}. 703 704@item in|out.buffer-count=@var{count} 705Sets the @var{count} of the buffers. 706 707@item in|out.try-poll=on|of 708Attempt to use poll mode with the device. Default is on. 709 710@item try-mmap=on|off 711Try using memory mapped device access. Default is off. 712 713@item exclusive=on|off 714Open the device in exclusive mode (vmix won't work in this case). 715Default is off. 716 717@item dsp-policy=@var{policy} 718Sets the timing policy (between 0 and 10, where smaller number means 719smaller latency but higher CPU usage). Use -1 to use buffer sizes 720specified by @code{buffer} and @code{buffer-count}. This option is 721ignored if you do not have OSS 4. Default is 5. 722 723@end table 724 725@item -audiodev pa,id=@var{id}[,@var{prop}[=@var{value}][,...]] 726Creates a backend using PulseAudio. This backend is available on most 727systems. 728 729PulseAudio specific options are: 730 731@table @option 732 733@item server=@var{server} 734Sets the PulseAudio @var{server} to connect to. 735 736@item in|out.name=@var{sink} 737Use the specified source/sink for recording/playback. 738 739@item in|out.latency=@var{usecs} 740Desired latency in microseconds. The PulseAudio server will try to honor this 741value but actual latencies may be lower or higher. 742 743@end table 744 745@item -audiodev sdl,id=@var{id}[,@var{prop}[=@var{value}][,...]] 746Creates a backend using SDL. This backend is available on most systems, 747but you should use your platform's native backend if possible. This 748backend has no backend specific properties. 749 750@item -audiodev spice,id=@var{id}[,@var{prop}[=@var{value}][,...]] 751Creates a backend that sends audio through SPICE. This backend requires 752@code{-spice} and automatically selected in that case, so usually you 753can ignore this option. This backend has no backend specific 754properties. 755 756@item -audiodev wav,id=@var{id}[,@var{prop}[=@var{value}][,...]] 757Creates a backend that writes audio to a WAV file. 758 759Backend specific options are: 760 761@table @option 762 763@item path=@var{path} 764Write recorded audio into the specified file. Default is 765@code{qemu.wav}. 766 767@end table 768ETEXI 769 770DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 771 "-soundhw c1,... enable audio support\n" 772 " and only specified sound cards (comma separated list)\n" 773 " use '-soundhw help' to get the list of supported cards\n" 774 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 775STEXI 776@item -soundhw @var{card1}[,@var{card2},...] or -soundhw all 777@findex -soundhw 778Enable audio and selected sound hardware. Use 'help' to print all 779available sound hardware. For example: 780 781@example 782@value{qemu_system_x86} -soundhw sb16,adlib disk.img 783@value{qemu_system_x86} -soundhw es1370 disk.img 784@value{qemu_system_x86} -soundhw ac97 disk.img 785@value{qemu_system_x86} -soundhw hda disk.img 786@value{qemu_system_x86} -soundhw all disk.img 787@value{qemu_system_x86} -soundhw help 788@end example 789 790Note that Linux's i810_audio OSS kernel (for AC97) module might 791require manually specifying clocking. 792 793@example 794modprobe i810_audio clocking=48000 795@end example 796ETEXI 797 798DEF("device", HAS_ARG, QEMU_OPTION_device, 799 "-device driver[,prop[=value][,...]]\n" 800 " add device (based on driver)\n" 801 " prop=value,... sets driver properties\n" 802 " use '-device help' to print all possible drivers\n" 803 " use '-device driver,help' to print all possible properties\n", 804 QEMU_ARCH_ALL) 805STEXI 806@item -device @var{driver}[,@var{prop}[=@var{value}][,...]] 807@findex -device 808Add device @var{driver}. @var{prop}=@var{value} sets driver 809properties. Valid properties depend on the driver. To get help on 810possible drivers and properties, use @code{-device help} and 811@code{-device @var{driver},help}. 812 813Some drivers are: 814@item -device ipmi-bmc-sim,id=@var{id}[,slave_addr=@var{val}][,sdrfile=@var{file}][,furareasize=@var{val}][,furdatafile=@var{file}][,guid=@var{uuid}] 815 816Add an IPMI BMC. This is a simulation of a hardware management 817interface processor that normally sits on a system. It provides 818a watchdog and the ability to reset and power control the system. 819You need to connect this to an IPMI interface to make it useful 820 821The IPMI slave address to use for the BMC. The default is 0x20. 822This address is the BMC's address on the I2C network of management 823controllers. If you don't know what this means, it is safe to ignore 824it. 825 826@table @option 827@item id=@var{id} 828The BMC id for interfaces to use this device. 829@item slave_addr=@var{val} 830Define slave address to use for the BMC. The default is 0x20. 831@item sdrfile=@var{file} 832file containing raw Sensor Data Records (SDR) data. The default is none. 833@item fruareasize=@var{val} 834size of a Field Replaceable Unit (FRU) area. The default is 1024. 835@item frudatafile=@var{file} 836file containing raw Field Replaceable Unit (FRU) inventory data. The default is none. 837@item guid=@var{uuid} 838value for the GUID for the BMC, in standard UUID format. If this is set, 839get "Get GUID" command to the BMC will return it. Otherwise "Get GUID" 840will return an error. 841@end table 842 843@item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}] 844 845Add a connection to an external IPMI BMC simulator. Instead of 846locally emulating the BMC like the above item, instead connect 847to an external entity that provides the IPMI services. 848 849A connection is made to an external BMC simulator. If you do this, it 850is strongly recommended that you use the "reconnect=" chardev option 851to reconnect to the simulator if the connection is lost. Note that if 852this is not used carefully, it can be a security issue, as the 853interface has the ability to send resets, NMIs, and power off the VM. 854It's best if QEMU makes a connection to an external simulator running 855on a secure port on localhost, so neither the simulator nor QEMU is 856exposed to any outside network. 857 858See the "lanserv/README.vm" file in the OpenIPMI library for more 859details on the external interface. 860 861@item -device isa-ipmi-kcs,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}] 862 863Add a KCS IPMI interafce on the ISA bus. This also adds a 864corresponding ACPI and SMBIOS entries, if appropriate. 865 866@table @option 867@item bmc=@var{id} 868The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 869@item ioport=@var{val} 870Define the I/O address of the interface. The default is 0xca0 for KCS. 871@item irq=@var{val} 872Define the interrupt to use. The default is 5. To disable interrupts, 873set this to 0. 874@end table 875 876@item -device isa-ipmi-bt,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}] 877 878Like the KCS interface, but defines a BT interface. The default port is 8790xe4 and the default interrupt is 5. 880 881ETEXI 882 883DEF("name", HAS_ARG, QEMU_OPTION_name, 884 "-name string1[,process=string2][,debug-threads=on|off]\n" 885 " set the name of the guest\n" 886 " string1 sets the window title and string2 the process name\n" 887 " When debug-threads is enabled, individual threads are given a separate name\n" 888 " NOTE: The thread names are for debugging and not a stable API.\n", 889 QEMU_ARCH_ALL) 890STEXI 891@item -name @var{name} 892@findex -name 893Sets the @var{name} of the guest. 894This name will be displayed in the SDL window caption. 895The @var{name} will also be used for the VNC server. 896Also optionally set the top visible process name in Linux. 897Naming of individual threads can also be enabled on Linux to aid debugging. 898ETEXI 899 900DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 901 "-uuid %08x-%04x-%04x-%04x-%012x\n" 902 " specify machine UUID\n", QEMU_ARCH_ALL) 903STEXI 904@item -uuid @var{uuid} 905@findex -uuid 906Set system UUID. 907ETEXI 908 909STEXI 910@end table 911ETEXI 912DEFHEADING() 913 914DEFHEADING(Block device options:) 915STEXI 916@table @option 917ETEXI 918 919DEF("fda", HAS_ARG, QEMU_OPTION_fda, 920 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 921DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 922STEXI 923@item -fda @var{file} 924@itemx -fdb @var{file} 925@findex -fda 926@findex -fdb 927Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}). 928ETEXI 929 930DEF("hda", HAS_ARG, QEMU_OPTION_hda, 931 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 932DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 933DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 934 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 935DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 936STEXI 937@item -hda @var{file} 938@itemx -hdb @var{file} 939@itemx -hdc @var{file} 940@itemx -hdd @var{file} 941@findex -hda 942@findex -hdb 943@findex -hdc 944@findex -hdd 945Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}). 946ETEXI 947 948DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 949 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 950 QEMU_ARCH_ALL) 951STEXI 952@item -cdrom @var{file} 953@findex -cdrom 954Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and 955@option{-cdrom} at the same time). You can use the host CD-ROM by 956using @file{/dev/cdrom} as filename. 957ETEXI 958 959DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 960 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 961 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 962 " [,read-only=on|off][,auto-read-only=on|off]\n" 963 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 964 " [,driver specific parameters...]\n" 965 " configure a block backend\n", QEMU_ARCH_ALL) 966STEXI 967@item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]] 968@findex -blockdev 969 970Define a new block driver node. Some of the options apply to all block drivers, 971other options are only accepted for a specific block driver. See below for a 972list of generic options and options for the most common block drivers. 973 974Options that expect a reference to another node (e.g. @code{file}) can be 975given in two ways. Either you specify the node name of an already existing node 976(file=@var{node-name}), or you define a new node inline, adding options 977for the referenced node after a dot (file.filename=@var{path},file.aio=native). 978 979A block driver node created with @option{-blockdev} can be used for a guest 980device by specifying its node name for the @code{drive} property in a 981@option{-device} argument that defines a block device. 982 983@table @option 984@item Valid options for any block driver node: 985 986@table @code 987@item driver 988Specifies the block driver to use for the given node. 989@item node-name 990This defines the name of the block driver node by which it will be referenced 991later. The name must be unique, i.e. it must not match the name of a different 992block driver node, or (if you use @option{-drive} as well) the ID of a drive. 993 994If no node name is specified, it is automatically generated. The generated node 995name is not intended to be predictable and changes between QEMU invocations. 996For the top level, an explicit node name must be specified. 997@item read-only 998Open the node read-only. Guest write attempts will fail. 999 1000Note that some block drivers support only read-only access, either generally or 1001in certain configurations. In this case, the default value 1002@option{read-only=off} does not work and the option must be specified 1003explicitly. 1004@item auto-read-only 1005If @option{auto-read-only=on} is set, QEMU may fall back to read-only usage 1006even when @option{read-only=off} is requested, or even switch between modes as 1007needed, e.g. depending on whether the image file is writable or whether a 1008writing user is attached to the node. 1009@item force-share 1010Override the image locking system of QEMU by forcing the node to utilize 1011weaker shared access for permissions where it would normally request exclusive 1012access. When there is the potential for multiple instances to have the same 1013file open (whether this invocation of QEMU is the first or the second 1014instance), both instances must permit shared access for the second instance to 1015succeed at opening the file. 1016 1017Enabling @option{force-share=on} requires @option{read-only=on}. 1018@item cache.direct 1019The host page cache can be avoided with @option{cache.direct=on}. This will 1020attempt to do disk IO directly to the guest's memory. QEMU may still perform an 1021internal copy of the data. 1022@item cache.no-flush 1023In case you don't care about data integrity over host failures, you can use 1024@option{cache.no-flush=on}. This option tells QEMU that it never needs to write 1025any data to the disk but can instead keep things in cache. If anything goes 1026wrong, like your host losing power, the disk storage getting disconnected 1027accidentally, etc. your image will most probably be rendered unusable. 1028@item discard=@var{discard} 1029@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls 1030whether @code{discard} (also known as @code{trim} or @code{unmap}) requests are 1031ignored or passed to the filesystem. Some machine types may not support 1032discard requests. 1033@item detect-zeroes=@var{detect-zeroes} 1034@var{detect-zeroes} is "off", "on" or "unmap" and enables the automatic 1035conversion of plain zero writes by the OS to driver specific optimized 1036zero write commands. You may even choose "unmap" if @var{discard} is set 1037to "unmap" to allow a zero write to be converted to an @code{unmap} operation. 1038@end table 1039 1040@item Driver-specific options for @code{file} 1041 1042This is the protocol-level block driver for accessing regular files. 1043 1044@table @code 1045@item filename 1046The path to the image file in the local filesystem 1047@item aio 1048Specifies the AIO backend (threads/native, default: threads) 1049@item locking 1050Specifies whether the image file is protected with Linux OFD / POSIX locks. The 1051default is to use the Linux Open File Descriptor API if available, otherwise no 1052lock is applied. (auto/on/off, default: auto) 1053@end table 1054Example: 1055@example 1056-blockdev driver=file,node-name=disk,filename=disk.img 1057@end example 1058 1059@item Driver-specific options for @code{raw} 1060 1061This is the image format block driver for raw images. It is usually 1062stacked on top of a protocol level block driver such as @code{file}. 1063 1064@table @code 1065@item file 1066Reference to or definition of the data source block driver node 1067(e.g. a @code{file} driver node) 1068@end table 1069Example 1: 1070@example 1071-blockdev driver=file,node-name=disk_file,filename=disk.img 1072-blockdev driver=raw,node-name=disk,file=disk_file 1073@end example 1074Example 2: 1075@example 1076-blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1077@end example 1078 1079@item Driver-specific options for @code{qcow2} 1080 1081This is the image format block driver for qcow2 images. It is usually 1082stacked on top of a protocol level block driver such as @code{file}. 1083 1084@table @code 1085@item file 1086Reference to or definition of the data source block driver node 1087(e.g. a @code{file} driver node) 1088 1089@item backing 1090Reference to or definition of the backing file block device (default is taken 1091from the image file). It is allowed to pass @code{null} here in order to disable 1092the default backing file. 1093 1094@item lazy-refcounts 1095Whether to enable the lazy refcounts feature (on/off; default is taken from the 1096image file) 1097 1098@item cache-size 1099The maximum total size of the L2 table and refcount block caches in bytes 1100(default: the sum of l2-cache-size and refcount-cache-size) 1101 1102@item l2-cache-size 1103The maximum size of the L2 table cache in bytes 1104(default: if cache-size is not specified - 32M on Linux platforms, and 8M on 1105non-Linux platforms; otherwise, as large as possible within the cache-size, 1106while permitting the requested or the minimal refcount cache size) 1107 1108@item refcount-cache-size 1109The maximum size of the refcount block cache in bytes 1110(default: 4 times the cluster size; or if cache-size is specified, the part of 1111it which is not used for the L2 cache) 1112 1113@item cache-clean-interval 1114Clean unused entries in the L2 and refcount caches. The interval is in seconds. 1115The default value is 600 on supporting platforms, and 0 on other platforms. 1116Setting it to 0 disables this feature. 1117 1118@item pass-discard-request 1119Whether discard requests to the qcow2 device should be forwarded to the data 1120source (on/off; default: on if discard=unmap is specified, off otherwise) 1121 1122@item pass-discard-snapshot 1123Whether discard requests for the data source should be issued when a snapshot 1124operation (e.g. deleting a snapshot) frees clusters in the qcow2 file (on/off; 1125default: on) 1126 1127@item pass-discard-other 1128Whether discard requests for the data source should be issued on other 1129occasions where a cluster gets freed (on/off; default: off) 1130 1131@item overlap-check 1132Which overlap checks to perform for writes to the image 1133(none/constant/cached/all; default: cached). For details or finer 1134granularity control refer to the QAPI documentation of @code{blockdev-add}. 1135@end table 1136 1137Example 1: 1138@example 1139-blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1140-blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1141@end example 1142Example 2: 1143@example 1144-blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1145@end example 1146 1147@item Driver-specific options for other drivers 1148Please refer to the QAPI documentation of the @code{blockdev-add} QMP command. 1149 1150@end table 1151 1152ETEXI 1153 1154DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1155 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1156 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1157 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1158 " [,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]\n" 1159 " [,readonly=on|off][,copy-on-read=on|off]\n" 1160 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1161 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1162 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1163 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1164 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1165 " [[,iops_size=is]]\n" 1166 " [[,group=g]]\n" 1167 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1168STEXI 1169@item -drive @var{option}[,@var{option}[,@var{option}[,...]]] 1170@findex -drive 1171 1172Define a new drive. This includes creating a block driver node (the backend) as 1173well as a guest device, and is mostly a shortcut for defining the corresponding 1174@option{-blockdev} and @option{-device} options. 1175 1176@option{-drive} accepts all options that are accepted by @option{-blockdev}. In 1177addition, it knows the following options: 1178 1179@table @option 1180@item file=@var{file} 1181This option defines which disk image (@pxref{disk_images}) to use with 1182this drive. If the filename contains comma, you must double it 1183(for instance, "file=my,,file" to use file "my,file"). 1184 1185Special files such as iSCSI devices can be specified using protocol 1186specific URLs. See the section for "Device URL Syntax" for more information. 1187@item if=@var{interface} 1188This option defines on which type on interface the drive is connected. 1189Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio, none. 1190@item bus=@var{bus},unit=@var{unit} 1191These options define where is connected the drive by defining the bus number and 1192the unit id. 1193@item index=@var{index} 1194This option defines where is connected the drive by using an index in the list 1195of available connectors of a given interface type. 1196@item media=@var{media} 1197This option defines the type of the media: disk or cdrom. 1198@item snapshot=@var{snapshot} 1199@var{snapshot} is "on" or "off" and controls snapshot mode for the given drive 1200(see @option{-snapshot}). 1201@item cache=@var{cache} 1202@var{cache} is "none", "writeback", "unsafe", "directsync" or "writethrough" 1203and controls how the host cache is used to access block data. This is a 1204shortcut that sets the @option{cache.direct} and @option{cache.no-flush} 1205options (as in @option{-blockdev}), and additionally @option{cache.writeback}, 1206which provides a default for the @option{write-cache} option of block guest 1207devices (as in @option{-device}). The modes correspond to the following 1208settings: 1209 1210@c Our texi2pod.pl script doesn't support @multitable, so fall back to using 1211@c plain ASCII art (well, UTF-8 art really). This looks okay both in the manpage 1212@c and the HTML output. 1213@example 1214@ │ cache.writeback cache.direct cache.no-flush 1215─────────────┼───────────────────────────────────────────────── 1216writeback │ on off off 1217none │ on on off 1218writethrough │ off off off 1219directsync │ off on off 1220unsafe │ on off on 1221@end example 1222 1223The default mode is @option{cache=writeback}. 1224 1225@item aio=@var{aio} 1226@var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO. 1227@item format=@var{format} 1228Specify which disk @var{format} will be used rather than detecting 1229the format. Can be used to specify format=raw to avoid interpreting 1230an untrusted format header. 1231@item werror=@var{action},rerror=@var{action} 1232Specify which @var{action} to take on write and read errors. Valid actions are: 1233"ignore" (ignore the error and try to continue), "stop" (pause QEMU), 1234"report" (report the error to the guest), "enospc" (pause QEMU only if the 1235host disk is full; report the error to the guest otherwise). 1236The default setting is @option{werror=enospc} and @option{rerror=report}. 1237@item copy-on-read=@var{copy-on-read} 1238@var{copy-on-read} is "on" or "off" and enables whether to copy read backing 1239file sectors into the image file. 1240@item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w} 1241Specify bandwidth throttling limits in bytes per second, either for all request 1242types or for reads or writes only. Small values can lead to timeouts or hangs 1243inside the guest. A safe minimum for disks is 2 MB/s. 1244@item bps_max=@var{bm},bps_rd_max=@var{rm},bps_wr_max=@var{wm} 1245Specify bursts in bytes per second, either for all request types or for reads 1246or writes only. Bursts allow the guest I/O to spike above the limit 1247temporarily. 1248@item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w} 1249Specify request rate limits in requests per second, either for all request 1250types or for reads or writes only. 1251@item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm} 1252Specify bursts in requests per second, either for all request types or for reads 1253or writes only. Bursts allow the guest I/O to spike above the limit 1254temporarily. 1255@item iops_size=@var{is} 1256Let every @var{is} bytes of a request count as a new request for iops 1257throttling purposes. Use this option to prevent guests from circumventing iops 1258limits by sending fewer but larger requests. 1259@item group=@var{g} 1260Join a throttling quota group with given name @var{g}. All drives that are 1261members of the same group are accounted for together. Use this option to 1262prevent guests from circumventing throttling limits by using many small disks 1263instead of a single larger disk. 1264@end table 1265 1266By default, the @option{cache.writeback=on} mode is used. It will report data 1267writes as completed as soon as the data is present in the host page cache. 1268This is safe as long as your guest OS makes sure to correctly flush disk caches 1269where needed. If your guest OS does not handle volatile disk write caches 1270correctly and your host crashes or loses power, then the guest may experience 1271data corruption. 1272 1273For such guests, you should consider using @option{cache.writeback=off}. This 1274means that the host page cache will be used to read and write data, but write 1275notification will be sent to the guest only after QEMU has made sure to flush 1276each write to the disk. Be aware that this has a major impact on performance. 1277 1278When using the @option{-snapshot} option, unsafe caching is always used. 1279 1280Copy-on-read avoids accessing the same backing file sectors repeatedly and is 1281useful when the backing file is over a slow network. By default copy-on-read 1282is off. 1283 1284Instead of @option{-cdrom} you can use: 1285@example 1286@value{qemu_system} -drive file=file,index=2,media=cdrom 1287@end example 1288 1289Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can 1290use: 1291@example 1292@value{qemu_system} -drive file=file,index=0,media=disk 1293@value{qemu_system} -drive file=file,index=1,media=disk 1294@value{qemu_system} -drive file=file,index=2,media=disk 1295@value{qemu_system} -drive file=file,index=3,media=disk 1296@end example 1297 1298You can open an image using pre-opened file descriptors from an fd set: 1299@example 1300@value{qemu_system} \ 1301 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \ 1302 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \ 1303 -drive file=/dev/fdset/2,index=0,media=disk 1304@end example 1305 1306You can connect a CDROM to the slave of ide0: 1307@example 1308@value{qemu_system_x86} -drive file=file,if=ide,index=1,media=cdrom 1309@end example 1310 1311If you don't specify the "file=" argument, you define an empty drive: 1312@example 1313@value{qemu_system_x86} -drive if=ide,index=1,media=cdrom 1314@end example 1315 1316Instead of @option{-fda}, @option{-fdb}, you can use: 1317@example 1318@value{qemu_system_x86} -drive file=file,index=0,if=floppy 1319@value{qemu_system_x86} -drive file=file,index=1,if=floppy 1320@end example 1321 1322By default, @var{interface} is "ide" and @var{index} is automatically 1323incremented: 1324@example 1325@value{qemu_system_x86} -drive file=a -drive file=b" 1326@end example 1327is interpreted like: 1328@example 1329@value{qemu_system_x86} -hda a -hdb b 1330@end example 1331ETEXI 1332 1333DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1334 "-mtdblock file use 'file' as on-board Flash memory image\n", 1335 QEMU_ARCH_ALL) 1336STEXI 1337@item -mtdblock @var{file} 1338@findex -mtdblock 1339Use @var{file} as on-board Flash memory image. 1340ETEXI 1341 1342DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1343 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1344STEXI 1345@item -sd @var{file} 1346@findex -sd 1347Use @var{file} as SecureDigital card image. 1348ETEXI 1349 1350DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1351 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1352STEXI 1353@item -pflash @var{file} 1354@findex -pflash 1355Use @var{file} as a parallel flash image. 1356ETEXI 1357 1358DEF("snapshot", 0, QEMU_OPTION_snapshot, 1359 "-snapshot write to temporary files instead of disk image files\n", 1360 QEMU_ARCH_ALL) 1361STEXI 1362@item -snapshot 1363@findex -snapshot 1364Write to temporary files instead of disk image files. In this case, 1365the raw disk image you use is not written back. You can however force 1366the write back by pressing @key{C-a s} (@pxref{disk_images}). 1367ETEXI 1368 1369DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1370 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1371 " [,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n" 1372 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1373 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1374 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1375 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1376 " [[,throttling.iops-size=is]]\n" 1377 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly]\n" 1378 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly]\n" 1379 "-fsdev synth,id=id\n", 1380 QEMU_ARCH_ALL) 1381 1382STEXI 1383 1384@item -fsdev local,id=@var{id},path=@var{path},security_model=@var{security_model} [,writeout=@var{writeout}][,readonly][,fmode=@var{fmode}][,dmode=@var{dmode}] [,throttling.@var{option}=@var{value}[,throttling.@var{option}=@var{value}[,...]]] 1385@itemx -fsdev proxy,id=@var{id},socket=@var{socket}[,writeout=@var{writeout}][,readonly] 1386@itemx -fsdev proxy,id=@var{id},sock_fd=@var{sock_fd}[,writeout=@var{writeout}][,readonly] 1387@itemx -fsdev synth,id=@var{id}[,readonly] 1388@findex -fsdev 1389Define a new file system device. Valid options are: 1390@table @option 1391@item local 1392Accesses to the filesystem are done by QEMU. 1393@item proxy 1394Accesses to the filesystem are done by virtfs-proxy-helper(1). 1395@item synth 1396Synthetic filesystem, only used by QTests. 1397@item id=@var{id} 1398Specifies identifier for this device. 1399@item path=@var{path} 1400Specifies the export path for the file system device. Files under 1401this path will be available to the 9p client on the guest. 1402@item security_model=@var{security_model} 1403Specifies the security model to be used for this export path. 1404Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none". 1405In "passthrough" security model, files are stored using the same 1406credentials as they are created on the guest. This requires QEMU 1407to run as root. In "mapped-xattr" security model, some of the file 1408attributes like uid, gid, mode bits and link target are stored as 1409file attributes. For "mapped-file" these attributes are stored in the 1410hidden .virtfs_metadata directory. Directories exported by this security model cannot 1411interact with other unix tools. "none" security model is same as 1412passthrough except the sever won't report failures if it fails to 1413set file attributes like ownership. Security model is mandatory 1414only for local fsdriver. Other fsdrivers (like proxy) don't take 1415security model as a parameter. 1416@item writeout=@var{writeout} 1417This is an optional argument. The only supported value is "immediate". 1418This means that host page cache will be used to read and write data but 1419write notification will be sent to the guest only when the data has been 1420reported as written by the storage subsystem. 1421@item readonly 1422Enables exporting 9p share as a readonly mount for guests. By default 1423read-write access is given. 1424@item socket=@var{socket} 1425Enables proxy filesystem driver to use passed socket file for communicating 1426with virtfs-proxy-helper(1). 1427@item sock_fd=@var{sock_fd} 1428Enables proxy filesystem driver to use passed socket descriptor for 1429communicating with virtfs-proxy-helper(1). Usually a helper like libvirt 1430will create socketpair and pass one of the fds as sock_fd. 1431@item fmode=@var{fmode} 1432Specifies the default mode for newly created files on the host. Works only 1433with security models "mapped-xattr" and "mapped-file". 1434@item dmode=@var{dmode} 1435Specifies the default mode for newly created directories on the host. Works 1436only with security models "mapped-xattr" and "mapped-file". 1437@item throttling.bps-total=@var{b},throttling.bps-read=@var{r},throttling.bps-write=@var{w} 1438Specify bandwidth throttling limits in bytes per second, either for all request 1439types or for reads or writes only. 1440@item throttling.bps-total-max=@var{bm},bps-read-max=@var{rm},bps-write-max=@var{wm} 1441Specify bursts in bytes per second, either for all request types or for reads 1442or writes only. Bursts allow the guest I/O to spike above the limit 1443temporarily. 1444@item throttling.iops-total=@var{i},throttling.iops-read=@var{r}, throttling.iops-write=@var{w} 1445Specify request rate limits in requests per second, either for all request 1446types or for reads or writes only. 1447@item throttling.iops-total-max=@var{im},throttling.iops-read-max=@var{irm}, throttling.iops-write-max=@var{iwm} 1448Specify bursts in requests per second, either for all request types or for reads 1449or writes only. Bursts allow the guest I/O to spike above the limit temporarily. 1450@item throttling.iops-size=@var{is} 1451Let every @var{is} bytes of a request count as a new request for iops 1452throttling purposes. 1453@end table 1454 1455-fsdev option is used along with -device driver "virtio-9p-...". 1456@item -device virtio-9p-@var{type},fsdev=@var{id},mount_tag=@var{mount_tag} 1457Options for virtio-9p-... driver are: 1458@table @option 1459@item @var{type} 1460Specifies the variant to be used. Supported values are "pci", "ccw" or "device", 1461depending on the machine type. 1462@item fsdev=@var{id} 1463Specifies the id value specified along with -fsdev option. 1464@item mount_tag=@var{mount_tag} 1465Specifies the tag name to be used by the guest to mount this export point. 1466@end table 1467 1468ETEXI 1469 1470DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1471 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1472 " [,id=id][,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1473 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly]\n" 1474 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly]\n" 1475 "-virtfs synth,mount_tag=tag[,id=id][,readonly]\n", 1476 QEMU_ARCH_ALL) 1477 1478STEXI 1479 1480@item -virtfs local,path=@var{path},mount_tag=@var{mount_tag} ,security_model=@var{security_model}[,writeout=@var{writeout}][,readonly] [,fmode=@var{fmode}][,dmode=@var{dmode}][,multidevs=@var{multidevs}] 1481@itemx -virtfs proxy,socket=@var{socket},mount_tag=@var{mount_tag} [,writeout=@var{writeout}][,readonly] 1482@itemx -virtfs proxy,sock_fd=@var{sock_fd},mount_tag=@var{mount_tag} [,writeout=@var{writeout}][,readonly] 1483@itemx -virtfs synth,mount_tag=@var{mount_tag} 1484@findex -virtfs 1485 1486Define a new filesystem device and expose it to the guest using a virtio-9p-device. The general form of a Virtual File system pass-through options are: 1487@table @option 1488@item local 1489Accesses to the filesystem are done by QEMU. 1490@item proxy 1491Accesses to the filesystem are done by virtfs-proxy-helper(1). 1492@item synth 1493Synthetic filesystem, only used by QTests. 1494@item id=@var{id} 1495Specifies identifier for the filesystem device 1496@item path=@var{path} 1497Specifies the export path for the file system device. Files under 1498this path will be available to the 9p client on the guest. 1499@item security_model=@var{security_model} 1500Specifies the security model to be used for this export path. 1501Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none". 1502In "passthrough" security model, files are stored using the same 1503credentials as they are created on the guest. This requires QEMU 1504to run as root. In "mapped-xattr" security model, some of the file 1505attributes like uid, gid, mode bits and link target are stored as 1506file attributes. For "mapped-file" these attributes are stored in the 1507hidden .virtfs_metadata directory. Directories exported by this security model cannot 1508interact with other unix tools. "none" security model is same as 1509passthrough except the sever won't report failures if it fails to 1510set file attributes like ownership. Security model is mandatory only 1511for local fsdriver. Other fsdrivers (like proxy) don't take security 1512model as a parameter. 1513@item writeout=@var{writeout} 1514This is an optional argument. The only supported value is "immediate". 1515This means that host page cache will be used to read and write data but 1516write notification will be sent to the guest only when the data has been 1517reported as written by the storage subsystem. 1518@item readonly 1519Enables exporting 9p share as a readonly mount for guests. By default 1520read-write access is given. 1521@item socket=@var{socket} 1522Enables proxy filesystem driver to use passed socket file for 1523communicating with virtfs-proxy-helper(1). Usually a helper like libvirt 1524will create socketpair and pass one of the fds as sock_fd. 1525@item sock_fd 1526Enables proxy filesystem driver to use passed 'sock_fd' as the socket 1527descriptor for interfacing with virtfs-proxy-helper(1). 1528@item fmode=@var{fmode} 1529Specifies the default mode for newly created files on the host. Works only 1530with security models "mapped-xattr" and "mapped-file". 1531@item dmode=@var{dmode} 1532Specifies the default mode for newly created directories on the host. Works 1533only with security models "mapped-xattr" and "mapped-file". 1534@item mount_tag=@var{mount_tag} 1535Specifies the tag name to be used by the guest to mount this export point. 1536@item multidevs=@var{multidevs} 1537Specifies how to deal with multiple devices being shared with a 9p export. 1538Supported behaviours are either "remap", "forbid" or "warn". The latter is 1539the default behaviour on which virtfs 9p expects only one device to be 1540shared with the same export, and if more than one device is shared and 1541accessed via the same 9p export then only a warning message is logged 1542(once) by qemu on host side. In order to avoid file ID collisions on guest 1543you should either create a separate virtfs export for each device to be 1544shared with guests (recommended way) or you might use "remap" instead which 1545allows you to share multiple devices with only one export instead, which is 1546achieved by remapping the original inode numbers from host to guest in a 1547way that would prevent such collisions. Remapping inodes in such use cases 1548is required because the original device IDs from host are never passed and 1549exposed on guest. Instead all files of an export shared with virtfs always 1550share the same device id on guest. So two files with identical inode 1551numbers but from actually different devices on host would otherwise cause a 1552file ID collision and hence potential misbehaviours on guest. "forbid" on 1553the other hand assumes like "warn" that only one device is shared by the 1554same export, however it will not only log a warning message but also 1555deny access to additional devices on guest. Note though that "forbid" does 1556currently not block all possible file access operations (e.g. readdir() 1557would still return entries from other devices). 1558@end table 1559ETEXI 1560 1561DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1562 "-iscsi [user=user][,password=password]\n" 1563 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1564 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1565 " [,timeout=timeout]\n" 1566 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1567 1568STEXI 1569@item -iscsi 1570@findex -iscsi 1571Configure iSCSI session parameters. 1572ETEXI 1573 1574STEXI 1575@end table 1576ETEXI 1577DEFHEADING() 1578 1579DEFHEADING(USB options:) 1580STEXI 1581@table @option 1582ETEXI 1583 1584DEF("usb", 0, QEMU_OPTION_usb, 1585 "-usb enable on-board USB host controller (if not enabled by default)\n", 1586 QEMU_ARCH_ALL) 1587STEXI 1588@item -usb 1589@findex -usb 1590Enable USB emulation on machine types with an on-board USB host controller (if 1591not enabled by default). Note that on-board USB host controllers may not 1592support USB 3.0. In this case @option{-device qemu-xhci} can be used instead 1593on machines with PCI. 1594ETEXI 1595 1596DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1597 "-usbdevice name add the host or guest USB device 'name'\n", 1598 QEMU_ARCH_ALL) 1599STEXI 1600 1601@item -usbdevice @var{devname} 1602@findex -usbdevice 1603Add the USB device @var{devname}. Note that this option is deprecated, 1604please use @code{-device usb-...} instead. @xref{usb_devices}. 1605 1606@table @option 1607 1608@item mouse 1609Virtual Mouse. This will override the PS/2 mouse emulation when activated. 1610 1611@item tablet 1612Pointer device that uses absolute coordinates (like a touchscreen). This 1613means QEMU is able to report the mouse position without having to grab the 1614mouse. Also overrides the PS/2 mouse emulation when activated. 1615 1616@item braille 1617Braille device. This will use BrlAPI to display the braille output on a real 1618or fake device. 1619 1620@end table 1621ETEXI 1622 1623STEXI 1624@end table 1625ETEXI 1626DEFHEADING() 1627 1628DEFHEADING(Display options:) 1629STEXI 1630@table @option 1631ETEXI 1632 1633DEF("display", HAS_ARG, QEMU_OPTION_display, 1634#if defined(CONFIG_SPICE) 1635 "-display spice-app[,gl=on|off]\n" 1636#endif 1637#if defined(CONFIG_SDL) 1638 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1639 " [,window_close=on|off][,gl=on|core|es|off]\n" 1640#endif 1641#if defined(CONFIG_GTK) 1642 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1643#endif 1644#if defined(CONFIG_VNC) 1645 "-display vnc=<display>[,<optargs>]\n" 1646#endif 1647#if defined(CONFIG_CURSES) 1648 "-display curses[,charset=<encoding>]\n" 1649#endif 1650#if defined(CONFIG_OPENGL) 1651 "-display egl-headless[,rendernode=<file>]\n" 1652#endif 1653 "-display none\n" 1654 " select display backend type\n" 1655 " The default display is equivalent to\n " 1656#if defined(CONFIG_GTK) 1657 "\"-display gtk\"\n" 1658#elif defined(CONFIG_SDL) 1659 "\"-display sdl\"\n" 1660#elif defined(CONFIG_COCOA) 1661 "\"-display cocoa\"\n" 1662#elif defined(CONFIG_VNC) 1663 "\"-vnc localhost:0,to=99,id=default\"\n" 1664#else 1665 "\"-display none\"\n" 1666#endif 1667 , QEMU_ARCH_ALL) 1668STEXI 1669@item -display @var{type} 1670@findex -display 1671Select type of display to use. This option is a replacement for the 1672old style -sdl/-curses/... options. Use @code{-display help} to list 1673the available display types. Valid values for @var{type} are 1674@table @option 1675@item sdl 1676Display video output via SDL (usually in a separate graphics 1677window; see the SDL documentation for other possibilities). 1678@item curses 1679Display video output via curses. For graphics device models which 1680support a text mode, QEMU can display this output using a 1681curses/ncurses interface. Nothing is displayed when the graphics 1682device is in graphical mode or if the graphics device does not support 1683a text mode. Generally only the VGA device models support text mode. 1684The font charset used by the guest can be specified with the 1685@code{charset} option, for example @code{charset=CP850} for IBM CP850 1686encoding. The default is @code{CP437}. 1687@item none 1688Do not display video output. The guest will still see an emulated 1689graphics card, but its output will not be displayed to the QEMU 1690user. This option differs from the -nographic option in that it 1691only affects what is done with video output; -nographic also changes 1692the destination of the serial and parallel port data. 1693@item gtk 1694Display video output in a GTK window. This interface provides drop-down 1695menus and other UI elements to configure and control the VM during 1696runtime. 1697@item vnc 1698Start a VNC server on display <arg> 1699@item egl-headless 1700Offload all OpenGL operations to a local DRI device. For any graphical display, 1701this display needs to be paired with either VNC or SPICE displays. 1702@item spice-app 1703Start QEMU as a Spice server and launch the default Spice client 1704application. The Spice server will redirect the serial consoles and 1705QEMU monitors. (Since 4.0) 1706@end table 1707ETEXI 1708 1709DEF("nographic", 0, QEMU_OPTION_nographic, 1710 "-nographic disable graphical output and redirect serial I/Os to console\n", 1711 QEMU_ARCH_ALL) 1712STEXI 1713@item -nographic 1714@findex -nographic 1715Normally, if QEMU is compiled with graphical window support, it displays 1716output such as guest graphics, guest console, and the QEMU monitor in a 1717window. With this option, you can totally disable graphical output so 1718that QEMU is a simple command line application. The emulated serial port 1719is redirected on the console and muxed with the monitor (unless 1720redirected elsewhere explicitly). Therefore, you can still use QEMU to 1721debug a Linux kernel with a serial console. Use @key{C-a h} for help on 1722switching between the console and monitor. 1723ETEXI 1724 1725DEF("curses", 0, QEMU_OPTION_curses, 1726 "-curses shorthand for -display curses\n", 1727 QEMU_ARCH_ALL) 1728STEXI 1729@item -curses 1730@findex -curses 1731Normally, if QEMU is compiled with graphical window support, it displays 1732output such as guest graphics, guest console, and the QEMU monitor in a 1733window. With this option, QEMU can display the VGA output when in text 1734mode using a curses/ncurses interface. Nothing is displayed in graphical 1735mode. 1736ETEXI 1737 1738DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1739 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1740 QEMU_ARCH_ALL) 1741STEXI 1742@item -alt-grab 1743@findex -alt-grab 1744Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also 1745affects the special keys (for fullscreen, monitor-mode switching, etc). 1746ETEXI 1747 1748DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1749 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1750 QEMU_ARCH_ALL) 1751STEXI 1752@item -ctrl-grab 1753@findex -ctrl-grab 1754Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also 1755affects the special keys (for fullscreen, monitor-mode switching, etc). 1756ETEXI 1757 1758DEF("no-quit", 0, QEMU_OPTION_no_quit, 1759 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1760STEXI 1761@item -no-quit 1762@findex -no-quit 1763Disable SDL window close capability. 1764ETEXI 1765 1766DEF("sdl", 0, QEMU_OPTION_sdl, 1767 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1768STEXI 1769@item -sdl 1770@findex -sdl 1771Enable SDL. 1772ETEXI 1773 1774DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1775 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1776 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1777 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1778 " [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n" 1779 " [,tls-ciphers=<list>]\n" 1780 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1781 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1782 " [,sasl][,password=<secret>][,disable-ticketing]\n" 1783 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1784 " [,jpeg-wan-compression=[auto|never|always]]\n" 1785 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1786 " [,streaming-video=[off|all|filter]][,disable-copy-paste]\n" 1787 " [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n" 1788 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1789 " [,gl=[on|off]][,rendernode=<file>]\n" 1790 " enable spice\n" 1791 " at least one of {port, tls-port} is mandatory\n", 1792 QEMU_ARCH_ALL) 1793STEXI 1794@item -spice @var{option}[,@var{option}[,...]] 1795@findex -spice 1796Enable the spice remote desktop protocol. Valid options are 1797 1798@table @option 1799 1800@item port=<nr> 1801Set the TCP port spice is listening on for plaintext channels. 1802 1803@item addr=<addr> 1804Set the IP address spice is listening on. Default is any address. 1805 1806@item ipv4 1807@itemx ipv6 1808@itemx unix 1809Force using the specified IP version. 1810 1811@item password=<secret> 1812Set the password you need to authenticate. 1813 1814@item sasl 1815Require that the client use SASL to authenticate with the spice. 1816The exact choice of authentication method used is controlled from the 1817system / user's SASL configuration file for the 'qemu' service. This 1818is typically found in /etc/sasl2/qemu.conf. If running QEMU as an 1819unprivileged user, an environment variable SASL_CONF_PATH can be used 1820to make it search alternate locations for the service config. 1821While some SASL auth methods can also provide data encryption (eg GSSAPI), 1822it is recommended that SASL always be combined with the 'tls' and 1823'x509' settings to enable use of SSL and server certificates. This 1824ensures a data encryption preventing compromise of authentication 1825credentials. 1826 1827@item disable-ticketing 1828Allow client connects without authentication. 1829 1830@item disable-copy-paste 1831Disable copy paste between the client and the guest. 1832 1833@item disable-agent-file-xfer 1834Disable spice-vdagent based file-xfer between the client and the guest. 1835 1836@item tls-port=<nr> 1837Set the TCP port spice is listening on for encrypted channels. 1838 1839@item x509-dir=<dir> 1840Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir 1841 1842@item x509-key-file=<file> 1843@itemx x509-key-password=<file> 1844@itemx x509-cert-file=<file> 1845@itemx x509-cacert-file=<file> 1846@itemx x509-dh-key-file=<file> 1847The x509 file names can also be configured individually. 1848 1849@item tls-ciphers=<list> 1850Specify which ciphers to use. 1851 1852@item tls-channel=[main|display|cursor|inputs|record|playback] 1853@itemx plaintext-channel=[main|display|cursor|inputs|record|playback] 1854Force specific channel to be used with or without TLS encryption. The 1855options can be specified multiple times to configure multiple 1856channels. The special name "default" can be used to set the default 1857mode. For channels which are not explicitly forced into one mode the 1858spice client is allowed to pick tls/plaintext as he pleases. 1859 1860@item image-compression=[auto_glz|auto_lz|quic|glz|lz|off] 1861Configure image compression (lossless). 1862Default is auto_glz. 1863 1864@item jpeg-wan-compression=[auto|never|always] 1865@itemx zlib-glz-wan-compression=[auto|never|always] 1866Configure wan image compression (lossy for slow links). 1867Default is auto. 1868 1869@item streaming-video=[off|all|filter] 1870Configure video stream detection. Default is off. 1871 1872@item agent-mouse=[on|off] 1873Enable/disable passing mouse events via vdagent. Default is on. 1874 1875@item playback-compression=[on|off] 1876Enable/disable audio stream compression (using celt 0.5.1). Default is on. 1877 1878@item seamless-migration=[on|off] 1879Enable/disable spice seamless migration. Default is off. 1880 1881@item gl=[on|off] 1882Enable/disable OpenGL context. Default is off. 1883 1884@item rendernode=<file> 1885DRM render node for OpenGL rendering. If not specified, it will pick 1886the first available. (Since 2.9) 1887 1888@end table 1889ETEXI 1890 1891DEF("portrait", 0, QEMU_OPTION_portrait, 1892 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 1893 QEMU_ARCH_ALL) 1894STEXI 1895@item -portrait 1896@findex -portrait 1897Rotate graphical output 90 deg left (only PXA LCD). 1898ETEXI 1899 1900DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 1901 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 1902 QEMU_ARCH_ALL) 1903STEXI 1904@item -rotate @var{deg} 1905@findex -rotate 1906Rotate graphical output some deg left (only PXA LCD). 1907ETEXI 1908 1909DEF("vga", HAS_ARG, QEMU_OPTION_vga, 1910 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 1911 " select video card type\n", QEMU_ARCH_ALL) 1912STEXI 1913@item -vga @var{type} 1914@findex -vga 1915Select type of VGA card to emulate. Valid values for @var{type} are 1916@table @option 1917@item cirrus 1918Cirrus Logic GD5446 Video card. All Windows versions starting from 1919Windows 95 should recognize and use this graphic card. For optimal 1920performances, use 16 bit color depth in the guest and the host OS. 1921(This card was the default before QEMU 2.2) 1922@item std 1923Standard VGA card with Bochs VBE extensions. If your guest OS 1924supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want 1925to use high resolution modes (>= 1280x1024x16) then you should use 1926this option. (This card is the default since QEMU 2.2) 1927@item vmware 1928VMWare SVGA-II compatible adapter. Use it if you have sufficiently 1929recent XFree86/XOrg server or Windows guest with a driver for this 1930card. 1931@item qxl 1932QXL paravirtual graphic card. It is VGA compatible (including VESA 19332.0 VBE support). Works best with qxl guest drivers installed though. 1934Recommended choice when using the spice protocol. 1935@item tcx 1936(sun4m only) Sun TCX framebuffer. This is the default framebuffer for 1937sun4m machines and offers both 8-bit and 24-bit colour depths at a 1938fixed resolution of 1024x768. 1939@item cg3 1940(sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer 1941for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP) 1942resolutions aimed at people wishing to run older Solaris versions. 1943@item virtio 1944Virtio VGA card. 1945@item none 1946Disable VGA card. 1947@end table 1948ETEXI 1949 1950DEF("full-screen", 0, QEMU_OPTION_full_screen, 1951 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 1952STEXI 1953@item -full-screen 1954@findex -full-screen 1955Start in full screen. 1956ETEXI 1957 1958DEF("g", HAS_ARG, QEMU_OPTION_g , 1959 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 1960 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 1961STEXI 1962@item -g @var{width}x@var{height}[x@var{depth}] 1963@findex -g 1964Set the initial graphical resolution and depth (PPC, SPARC only). 1965ETEXI 1966 1967DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 1968 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 1969STEXI 1970@item -vnc @var{display}[,@var{option}[,@var{option}[,...]]] 1971@findex -vnc 1972Normally, if QEMU is compiled with graphical window support, it displays 1973output such as guest graphics, guest console, and the QEMU monitor in a 1974window. With this option, you can have QEMU listen on VNC display 1975@var{display} and redirect the VGA display over the VNC session. It is 1976very useful to enable the usb tablet device when using this option 1977(option @option{-device usb-tablet}). When using the VNC display, you 1978must use the @option{-k} parameter to set the keyboard layout if you are 1979not using en-us. Valid syntax for the @var{display} is 1980 1981@table @option 1982 1983@item to=@var{L} 1984 1985With this option, QEMU will try next available VNC @var{display}s, until the 1986number @var{L}, if the origianlly defined "-vnc @var{display}" is not 1987available, e.g. port 5900+@var{display} is already used by another 1988application. By default, to=0. 1989 1990@item @var{host}:@var{d} 1991 1992TCP connections will only be allowed from @var{host} on display @var{d}. 1993By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can 1994be omitted in which case the server will accept connections from any host. 1995 1996@item unix:@var{path} 1997 1998Connections will be allowed over UNIX domain sockets where @var{path} is the 1999location of a unix socket to listen for connections on. 2000 2001@item none 2002 2003VNC is initialized but not started. The monitor @code{change} command 2004can be used to later start the VNC server. 2005 2006@end table 2007 2008Following the @var{display} value there may be one or more @var{option} flags 2009separated by commas. Valid options are 2010 2011@table @option 2012 2013@item reverse 2014 2015Connect to a listening VNC client via a ``reverse'' connection. The 2016client is specified by the @var{display}. For reverse network 2017connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument 2018is a TCP port number, not a display number. 2019 2020@item websocket 2021 2022Opens an additional TCP listening port dedicated to VNC Websocket connections. 2023If a bare @var{websocket} option is given, the Websocket port is 20245700+@var{display}. An alternative port can be specified with the 2025syntax @code{websocket}=@var{port}. 2026 2027If @var{host} is specified connections will only be allowed from this host. 2028It is possible to control the websocket listen address independently, using 2029the syntax @code{websocket}=@var{host}:@var{port}. 2030 2031If no TLS credentials are provided, the websocket connection runs in 2032unencrypted mode. If TLS credentials are provided, the websocket connection 2033requires encrypted client connections. 2034 2035@item password 2036 2037Require that password based authentication is used for client connections. 2038 2039The password must be set separately using the @code{set_password} command in 2040the @ref{pcsys_monitor}. The syntax to change your password is: 2041@code{set_password <protocol> <password>} where <protocol> could be either 2042"vnc" or "spice". 2043 2044If you would like to change <protocol> password expiration, you should use 2045@code{expire_password <protocol> <expiration-time>} where expiration time could 2046be one of the following options: now, never, +seconds or UNIX time of 2047expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800 2048to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this 2049date and time). 2050 2051You can also use keywords "now" or "never" for the expiration time to 2052allow <protocol> password to expire immediately or never expire. 2053 2054@item tls-creds=@var{ID} 2055 2056Provides the ID of a set of TLS credentials to use to secure the 2057VNC server. They will apply to both the normal VNC server socket 2058and the websocket socket (if enabled). Setting TLS credentials 2059will cause the VNC server socket to enable the VeNCrypt auth 2060mechanism. The credentials should have been previously created 2061using the @option{-object tls-creds} argument. 2062 2063@item tls-authz=@var{ID} 2064 2065Provides the ID of the QAuthZ authorization object against which 2066the client's x509 distinguished name will validated. This object is 2067only resolved at time of use, so can be deleted and recreated on the 2068fly while the VNC server is active. If missing, it will default 2069to denying access. 2070 2071@item sasl 2072 2073Require that the client use SASL to authenticate with the VNC server. 2074The exact choice of authentication method used is controlled from the 2075system / user's SASL configuration file for the 'qemu' service. This 2076is typically found in /etc/sasl2/qemu.conf. If running QEMU as an 2077unprivileged user, an environment variable SASL_CONF_PATH can be used 2078to make it search alternate locations for the service config. 2079While some SASL auth methods can also provide data encryption (eg GSSAPI), 2080it is recommended that SASL always be combined with the 'tls' and 2081'x509' settings to enable use of SSL and server certificates. This 2082ensures a data encryption preventing compromise of authentication 2083credentials. See the @ref{vnc_security} section for details on using 2084SASL authentication. 2085 2086@item sasl-authz=@var{ID} 2087 2088Provides the ID of the QAuthZ authorization object against which 2089the client's SASL username will validated. This object is 2090only resolved at time of use, so can be deleted and recreated on the 2091fly while the VNC server is active. If missing, it will default 2092to denying access. 2093 2094@item acl 2095 2096Legacy method for enabling authorization of clients against the 2097x509 distinguished name and SASL username. It results in the creation 2098of two @code{authz-list} objects with IDs of @code{vnc.username} and 2099@code{vnc.x509dname}. The rules for these objects must be configured 2100with the HMP ACL commands. 2101 2102This option is deprecated and should no longer be used. The new 2103@option{sasl-authz} and @option{tls-authz} options are a 2104replacement. 2105 2106@item lossy 2107 2108Enable lossy compression methods (gradient, JPEG, ...). If this 2109option is set, VNC client may receive lossy framebuffer updates 2110depending on its encoding settings. Enabling this option can save 2111a lot of bandwidth at the expense of quality. 2112 2113@item non-adaptive 2114 2115Disable adaptive encodings. Adaptive encodings are enabled by default. 2116An adaptive encoding will try to detect frequently updated screen regions, 2117and send updates in these regions using a lossy encoding (like JPEG). 2118This can be really helpful to save bandwidth when playing videos. Disabling 2119adaptive encodings restores the original static behavior of encodings 2120like Tight. 2121 2122@item share=[allow-exclusive|force-shared|ignore] 2123 2124Set display sharing policy. 'allow-exclusive' allows clients to ask 2125for exclusive access. As suggested by the rfb spec this is 2126implemented by dropping other connections. Connecting multiple 2127clients in parallel requires all clients asking for a shared session 2128(vncviewer: -shared switch). This is the default. 'force-shared' 2129disables exclusive client access. Useful for shared desktop sessions, 2130where you don't want someone forgetting specify -shared disconnect 2131everybody else. 'ignore' completely ignores the shared flag and 2132allows everybody connect unconditionally. Doesn't conform to the rfb 2133spec but is traditional QEMU behavior. 2134 2135@item key-delay-ms 2136 2137Set keyboard delay, for key down and key up events, in milliseconds. 2138Default is 10. Keyboards are low-bandwidth devices, so this slowdown 2139can help the device and guest to keep up and not lose events in case 2140events are arriving in bulk. Possible causes for the latter are flaky 2141network connections, or scripts for automated testing. 2142 2143@item audiodev=@var{audiodev} 2144 2145Use the specified @var{audiodev} when the VNC client requests audio 2146transmission. When not using an -audiodev argument, this option must 2147be omitted, otherwise is must be present and specify a valid audiodev. 2148 2149@end table 2150ETEXI 2151 2152STEXI 2153@end table 2154ETEXI 2155ARCHHEADING(, QEMU_ARCH_I386) 2156 2157ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2158STEXI 2159@table @option 2160ETEXI 2161 2162DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2163 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2164 QEMU_ARCH_I386) 2165STEXI 2166@item -win2k-hack 2167@findex -win2k-hack 2168Use it when installing Windows 2000 to avoid a disk full bug. After 2169Windows 2000 is installed, you no longer need this option (this option 2170slows down the IDE transfers). 2171ETEXI 2172 2173DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2174 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2175 QEMU_ARCH_I386) 2176STEXI 2177@item -no-fd-bootchk 2178@findex -no-fd-bootchk 2179Disable boot signature checking for floppy disks in BIOS. May 2180be needed to boot from old floppy disks. 2181ETEXI 2182 2183DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2184 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2185STEXI 2186@item -no-acpi 2187@findex -no-acpi 2188Disable ACPI (Advanced Configuration and Power Interface) support. Use 2189it if your guest OS complains about ACPI problems (PC target machine 2190only). 2191ETEXI 2192 2193DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2194 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2195STEXI 2196@item -no-hpet 2197@findex -no-hpet 2198Disable HPET support. 2199ETEXI 2200 2201DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2202 "-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" 2203 " ACPI table description\n", QEMU_ARCH_I386) 2204STEXI 2205@item -acpitable [sig=@var{str}][,rev=@var{n}][,oem_id=@var{str}][,oem_table_id=@var{str}][,oem_rev=@var{n}] [,asl_compiler_id=@var{str}][,asl_compiler_rev=@var{n}][,data=@var{file1}[:@var{file2}]...] 2206@findex -acpitable 2207Add ACPI table with specified header fields and context from specified files. 2208For file=, take whole ACPI table from the specified files, including all 2209ACPI headers (possible overridden by other options). 2210For data=, only data 2211portion of the table is used, all header information is specified in the 2212command line. 2213If a SLIC table is supplied to QEMU, then the SLIC's oem_id and oem_table_id 2214fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order 2215to ensure the field matches required by the Microsoft SLIC spec and the ACPI 2216spec. 2217ETEXI 2218 2219DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2220 "-smbios file=binary\n" 2221 " load SMBIOS entry from binary file\n" 2222 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2223 " [,uefi=on|off]\n" 2224 " specify SMBIOS type 0 fields\n" 2225 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2226 " [,uuid=uuid][,sku=str][,family=str]\n" 2227 " specify SMBIOS type 1 fields\n" 2228 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2229 " [,asset=str][,location=str]\n" 2230 " specify SMBIOS type 2 fields\n" 2231 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2232 " [,sku=str]\n" 2233 " specify SMBIOS type 3 fields\n" 2234 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2235 " [,asset=str][,part=str]\n" 2236 " specify SMBIOS type 4 fields\n" 2237 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2238 " [,asset=str][,part=str][,speed=%d]\n" 2239 " specify SMBIOS type 17 fields\n", 2240 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2241STEXI 2242@item -smbios file=@var{binary} 2243@findex -smbios 2244Load SMBIOS entry from binary file. 2245 2246@item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off] 2247Specify SMBIOS type 0 fields 2248 2249@item -smbios type=1[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,uuid=@var{uuid}][,sku=@var{str}][,family=@var{str}] 2250Specify SMBIOS type 1 fields 2251 2252@item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}] 2253Specify SMBIOS type 2 fields 2254 2255@item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}] 2256Specify SMBIOS type 3 fields 2257 2258@item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}] 2259Specify SMBIOS type 4 fields 2260 2261@item -smbios type=17[,loc_pfx=@var{str}][,bank=@var{str}][,manufacturer=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}][,speed=@var{%d}] 2262Specify SMBIOS type 17 fields 2263ETEXI 2264 2265STEXI 2266@end table 2267ETEXI 2268DEFHEADING() 2269 2270DEFHEADING(Network options:) 2271STEXI 2272@table @option 2273ETEXI 2274 2275DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2276#ifdef CONFIG_SLIRP 2277 "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n" 2278 " [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2279 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2280 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2281 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2282#ifndef _WIN32 2283 "[,smb=dir[,smbserver=addr]]\n" 2284#endif 2285 " configure a user mode network backend with ID 'str',\n" 2286 " its DHCP server and optional services\n" 2287#endif 2288#ifdef _WIN32 2289 "-netdev tap,id=str,ifname=name\n" 2290 " configure a host TAP network backend with ID 'str'\n" 2291#else 2292 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2293 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2294 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2295 " [,poll-us=n]\n" 2296 " configure a host TAP network backend with ID 'str'\n" 2297 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2298 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2299 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2300 " to deconfigure it\n" 2301 " use '[down]script=no' to disable script execution\n" 2302 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2303 " configure it\n" 2304 " use 'fd=h' to connect to an already opened TAP interface\n" 2305 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2306 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2307 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2308 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2309 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2310 " use vhost=on to enable experimental in kernel accelerator\n" 2311 " (only has effect for virtio guests which use MSIX)\n" 2312 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2313 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2314 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2315 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2316 " use 'poll-us=n' to speciy the maximum number of microseconds that could be\n" 2317 " spent on busy polling for vhost net\n" 2318 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2319 " configure a host TAP network backend with ID 'str' that is\n" 2320 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2321 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2322#endif 2323#ifdef __linux__ 2324 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2325 " [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n" 2326 " [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n" 2327 " [,rxcookie=rxcookie][,offset=offset]\n" 2328 " configure a network backend with ID 'str' connected to\n" 2329 " an Ethernet over L2TPv3 pseudowire.\n" 2330 " Linux kernel 3.3+ as well as most routers can talk\n" 2331 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2332 " VM to a router and even VM to Host. It is a nearly-universal\n" 2333 " standard (RFC3391). Note - this implementation uses static\n" 2334 " pre-configured tunnels (same as the Linux kernel).\n" 2335 " use 'src=' to specify source address\n" 2336 " use 'dst=' to specify destination address\n" 2337 " use 'udp=on' to specify udp encapsulation\n" 2338 " use 'srcport=' to specify source udp port\n" 2339 " use 'dstport=' to specify destination udp port\n" 2340 " use 'ipv6=on' to force v6\n" 2341 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2342 " well as a weak security measure\n" 2343 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2344 " use 'txcookie=0x012345678' to specify a txcookie\n" 2345 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2346 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2347 " use 'pincounter=on' to work around broken counter handling in peer\n" 2348 " use 'offset=X' to add an extra offset between header and data\n" 2349#endif 2350 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2351 " configure a network backend to connect to another network\n" 2352 " using a socket connection\n" 2353 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2354 " configure a network backend to connect to a multicast maddr and port\n" 2355 " use 'localaddr=addr' to specify the host address to send packets from\n" 2356 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2357 " configure a network backend to connect to another network\n" 2358 " using an UDP tunnel\n" 2359#ifdef CONFIG_VDE 2360 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2361 " configure a network backend to connect to port 'n' of a vde switch\n" 2362 " running on host and listening for incoming connections on 'socketpath'.\n" 2363 " Use group 'groupname' and mode 'octalmode' to change default\n" 2364 " ownership and permissions for communication port.\n" 2365#endif 2366#ifdef CONFIG_NETMAP 2367 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2368 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2369 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2370 " netmap device, defaults to '/dev/netmap')\n" 2371#endif 2372#ifdef CONFIG_POSIX 2373 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2374 " configure a vhost-user network, backed by a chardev 'dev'\n" 2375#endif 2376 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2377 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2378DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2379 "-nic [tap|bridge|" 2380#ifdef CONFIG_SLIRP 2381 "user|" 2382#endif 2383#ifdef __linux__ 2384 "l2tpv3|" 2385#endif 2386#ifdef CONFIG_VDE 2387 "vde|" 2388#endif 2389#ifdef CONFIG_NETMAP 2390 "netmap|" 2391#endif 2392#ifdef CONFIG_POSIX 2393 "vhost-user|" 2394#endif 2395 "socket][,option][,...][mac=macaddr]\n" 2396 " initialize an on-board / default host NIC (using MAC address\n" 2397 " macaddr) and connect it to the given host network backend\n" 2398 "-nic none use it alone to have zero network devices (the default is to\n" 2399 " provided a 'user' network connection)\n", 2400 QEMU_ARCH_ALL) 2401DEF("net", HAS_ARG, QEMU_OPTION_net, 2402 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2403 " configure or create an on-board (or machine default) NIC and\n" 2404 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2405 "-net [" 2406#ifdef CONFIG_SLIRP 2407 "user|" 2408#endif 2409 "tap|" 2410 "bridge|" 2411#ifdef CONFIG_VDE 2412 "vde|" 2413#endif 2414#ifdef CONFIG_NETMAP 2415 "netmap|" 2416#endif 2417 "socket][,option][,option][,...]\n" 2418 " old way to initialize a host network interface\n" 2419 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2420STEXI 2421@item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn] 2422@findex -nic 2423This option is a shortcut for configuring both the on-board (default) guest 2424NIC hardware and the host network backend in one go. The host backend options 2425are the same as with the corresponding @option{-netdev} options below. 2426The guest NIC model can be set with @option{model=@var{modelname}}. 2427Use @option{model=help} to list the available device types. 2428The hardware MAC address can be set with @option{mac=@var{macaddr}}. 2429 2430The following two example do exactly the same, to show how @option{-nic} can 2431be used to shorten the command line length: 2432@example 2433@value{qemu_system} -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2434@value{qemu_system} -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2435@end example 2436 2437@item -nic none 2438Indicate that no network devices should be configured. It is used to override 2439the default configuration (default NIC with ``user'' host network backend) 2440which is activated if no other networking options are provided. 2441 2442@item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...] 2443@findex -netdev 2444Configure user mode host network backend which requires no administrator 2445privilege to run. Valid options are: 2446 2447@table @option 2448@item id=@var{id} 2449Assign symbolic name for use in monitor commands. 2450 2451@item ipv4=on|off and ipv6=on|off 2452Specify that either IPv4 or IPv6 must be enabled. If neither is specified 2453both protocols are enabled. 2454 2455@item net=@var{addr}[/@var{mask}] 2456Set IP network address the guest will see. Optionally specify the netmask, 2457either in the form a.b.c.d or as number of valid top-most bits. Default is 245810.0.2.0/24. 2459 2460@item host=@var{addr} 2461Specify the guest-visible address of the host. Default is the 2nd IP in the 2462guest network, i.e. x.x.x.2. 2463 2464@item ipv6-net=@var{addr}[/@var{int}] 2465Set IPv6 network address the guest will see (default is fec0::/64). The 2466network prefix is given in the usual hexadecimal IPv6 address 2467notation. The prefix size is optional, and is given as the number of 2468valid top-most bits (default is 64). 2469 2470@item ipv6-host=@var{addr} 2471Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in 2472the guest network, i.e. xxxx::2. 2473 2474@item restrict=on|off 2475If this option is enabled, the guest will be isolated, i.e. it will not be 2476able to contact the host and no guest IP packets will be routed over the host 2477to the outside. This option does not affect any explicitly set forwarding rules. 2478 2479@item hostname=@var{name} 2480Specifies the client hostname reported by the built-in DHCP server. 2481 2482@item dhcpstart=@var{addr} 2483Specify the first of the 16 IPs the built-in DHCP server can assign. Default 2484is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31. 2485 2486@item dns=@var{addr} 2487Specify the guest-visible address of the virtual nameserver. The address must 2488be different from the host address. Default is the 3rd IP in the guest network, 2489i.e. x.x.x.3. 2490 2491@item ipv6-dns=@var{addr} 2492Specify the guest-visible address of the IPv6 virtual nameserver. The address 2493must be different from the host address. Default is the 3rd IP in the guest 2494network, i.e. xxxx::3. 2495 2496@item dnssearch=@var{domain} 2497Provides an entry for the domain-search list sent by the built-in 2498DHCP server. More than one domain suffix can be transmitted by specifying 2499this option multiple times. If supported, this will cause the guest to 2500automatically try to append the given domain suffix(es) in case a domain name 2501can not be resolved. 2502 2503Example: 2504@example 2505@value{qemu_system} -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2506@end example 2507 2508@item domainname=@var{domain} 2509Specifies the client domain name reported by the built-in DHCP server. 2510 2511@item tftp=@var{dir} 2512When using the user mode network stack, activate a built-in TFTP 2513server. The files in @var{dir} will be exposed as the root of a TFTP server. 2514The TFTP client on the guest must be configured in binary mode (use the command 2515@code{bin} of the Unix TFTP client). 2516 2517@item tftp-server-name=@var{name} 2518In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option 251966). This can be used to advise the guest to load boot files or configurations 2520from a different server than the host address. 2521 2522@item bootfile=@var{file} 2523When using the user mode network stack, broadcast @var{file} as the BOOTP 2524filename. In conjunction with @option{tftp}, this can be used to network boot 2525a guest from a local directory. 2526 2527Example (using pxelinux): 2528@example 2529@value{qemu_system} -hda linux.img -boot n -device e1000,netdev=n1 \ 2530 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2531@end example 2532 2533@item smb=@var{dir}[,smbserver=@var{addr}] 2534When using the user mode network stack, activate a built-in SMB 2535server so that Windows OSes can access to the host files in @file{@var{dir}} 2536transparently. The IP address of the SMB server can be set to @var{addr}. By 2537default the 4th IP in the guest network is used, i.e. x.x.x.4. 2538 2539In the guest Windows OS, the line: 2540@example 254110.0.2.4 smbserver 2542@end example 2543must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me) 2544or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000). 2545 2546Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}. 2547 2548Note that a SAMBA server must be installed on the host OS. 2549 2550@item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport} 2551Redirect incoming TCP or UDP connections to the host port @var{hostport} to 2552the guest IP address @var{guestaddr} on guest port @var{guestport}. If 2553@var{guestaddr} is not specified, its value is x.x.x.15 (default first address 2554given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can 2555be bound to a specific host interface. If no connection type is set, TCP is 2556used. This option can be given multiple times. 2557 2558For example, to redirect host X11 connection from screen 1 to guest 2559screen 0, use the following: 2560 2561@example 2562# on the host 2563@value{qemu_system} -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2564# this host xterm should open in the guest X11 server 2565xterm -display :1 2566@end example 2567 2568To redirect telnet connections from host port 5555 to telnet port on 2569the guest, use the following: 2570 2571@example 2572# on the host 2573@value{qemu_system} -nic user,hostfwd=tcp::5555-:23 2574telnet localhost 5555 2575@end example 2576 2577Then when you use on the host @code{telnet localhost 5555}, you 2578connect to the guest telnet server. 2579 2580@item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev} 2581@itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command} 2582Forward guest TCP connections to the IP address @var{server} on port @var{port} 2583to the character device @var{dev} or to a program executed by @var{cmd:command} 2584which gets spawned for each connection. This option can be given multiple times. 2585 2586You can either use a chardev directly and have that one used throughout QEMU's 2587lifetime, like in the following example: 2588 2589@example 2590# open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2591# the guest accesses it 2592@value{qemu_system} -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2593@end example 2594 2595Or you can execute a command on every TCP connection established by the guest, 2596so that QEMU behaves similar to an inetd process for that virtual server: 2597 2598@example 2599# call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2600# and connect the TCP stream to its stdin/stdout 2601@value{qemu_system} -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2602@end example 2603 2604@end table 2605 2606@item -netdev tap,id=@var{id}[,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}] 2607Configure a host TAP network backend with ID @var{id}. 2608 2609Use the network script @var{file} to configure it and the network script 2610@var{dfile} to deconfigure it. If @var{name} is not provided, the OS 2611automatically provides one. The default network configure script is 2612@file{/etc/qemu-ifup} and the default network deconfigure script is 2613@file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no} 2614to disable script execution. 2615 2616If running QEMU as an unprivileged user, use the network helper 2617@var{helper} to configure the TAP interface and attach it to the bridge. 2618The default network helper executable is @file{/path/to/qemu-bridge-helper} 2619and the default bridge device is @file{br0}. 2620 2621@option{fd}=@var{h} can be used to specify the handle of an already 2622opened host TAP interface. 2623 2624Examples: 2625 2626@example 2627#launch a QEMU instance with the default network script 2628@value{qemu_system} linux.img -nic tap 2629@end example 2630 2631@example 2632#launch a QEMU instance with two NICs, each one connected 2633#to a TAP device 2634@value{qemu_system} linux.img \ 2635 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \ 2636 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2637@end example 2638 2639@example 2640#launch a QEMU instance with the default network helper to 2641#connect a TAP device to bridge br0 2642@value{qemu_system} linux.img -device virtio-net-pci,netdev=n1 \ 2643 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2644@end example 2645 2646@item -netdev bridge,id=@var{id}[,br=@var{bridge}][,helper=@var{helper}] 2647Connect a host TAP network interface to a host bridge device. 2648 2649Use the network helper @var{helper} to configure the TAP interface and 2650attach it to the bridge. The default network helper executable is 2651@file{/path/to/qemu-bridge-helper} and the default bridge 2652device is @file{br0}. 2653 2654Examples: 2655 2656@example 2657#launch a QEMU instance with the default network helper to 2658#connect a TAP device to bridge br0 2659@value{qemu_system} linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2660@end example 2661 2662@example 2663#launch a QEMU instance with the default network helper to 2664#connect a TAP device to bridge qemubr0 2665@value{qemu_system} linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2666@end example 2667 2668@item -netdev socket,id=@var{id}[,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}] 2669 2670This host network backend can be used to connect the guest's network to 2671another QEMU virtual machine using a TCP socket connection. If @option{listen} 2672is specified, QEMU waits for incoming connections on @var{port} 2673(@var{host} is optional). @option{connect} is used to connect to 2674another QEMU instance using the @option{listen} option. @option{fd}=@var{h} 2675specifies an already opened TCP socket. 2676 2677Example: 2678@example 2679# launch a first QEMU instance 2680@value{qemu_system} linux.img \ 2681 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2682 -netdev socket,id=n1,listen=:1234 2683# connect the network of this instance to the network of the first instance 2684@value{qemu_system} linux.img \ 2685 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \ 2686 -netdev socket,id=n2,connect=127.0.0.1:1234 2687@end example 2688 2689@item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]] 2690 2691Configure a socket host network backend to share the guest's network traffic 2692with another QEMU virtual machines using a UDP multicast socket, effectively 2693making a bus for every QEMU with same multicast address @var{maddr} and @var{port}. 2694NOTES: 2695@enumerate 2696@item 2697Several QEMU can be running on different hosts and share same bus (assuming 2698correct multicast setup for these hosts). 2699@item 2700mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see 2701@url{http://user-mode-linux.sf.net}. 2702@item 2703Use @option{fd=h} to specify an already opened UDP multicast socket. 2704@end enumerate 2705 2706Example: 2707@example 2708# launch one QEMU instance 2709@value{qemu_system} linux.img \ 2710 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2711 -netdev socket,id=n1,mcast=230.0.0.1:1234 2712# launch another QEMU instance on same "bus" 2713@value{qemu_system} linux.img \ 2714 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \ 2715 -netdev socket,id=n2,mcast=230.0.0.1:1234 2716# launch yet another QEMU instance on same "bus" 2717@value{qemu_system} linux.img \ 2718 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \ 2719 -netdev socket,id=n3,mcast=230.0.0.1:1234 2720@end example 2721 2722Example (User Mode Linux compat.): 2723@example 2724# launch QEMU instance (note mcast address selected is UML's default) 2725@value{qemu_system} linux.img \ 2726 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2727 -netdev socket,id=n1,mcast=239.192.168.1:1102 2728# launch UML 2729/path/to/linux ubd0=/path/to/root_fs eth0=mcast 2730@end example 2731 2732Example (send packets from host's 1.2.3.4): 2733@example 2734@value{qemu_system} linux.img \ 2735 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2736 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2737@end example 2738 2739@item -netdev l2tpv3,id=@var{id},src=@var{srcaddr},dst=@var{dstaddr}[,srcport=@var{srcport}][,dstport=@var{dstport}],txsession=@var{txsession}[,rxsession=@var{rxsession}][,ipv6][,udp][,cookie64][,counter][,pincounter][,txcookie=@var{txcookie}][,rxcookie=@var{rxcookie}][,offset=@var{offset}] 2740Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3391) is a 2741popular protocol to transport Ethernet (and other Layer 2) data frames between 2742two systems. It is present in routers, firewalls and the Linux kernel 2743(from version 3.3 onwards). 2744 2745This transport allows a VM to communicate to another VM, router or firewall directly. 2746 2747@table @option 2748@item src=@var{srcaddr} 2749 source address (mandatory) 2750@item dst=@var{dstaddr} 2751 destination address (mandatory) 2752@item udp 2753 select udp encapsulation (default is ip). 2754@item srcport=@var{srcport} 2755 source udp port. 2756@item dstport=@var{dstport} 2757 destination udp port. 2758@item ipv6 2759 force v6, otherwise defaults to v4. 2760@item rxcookie=@var{rxcookie} 2761@itemx txcookie=@var{txcookie} 2762 Cookies are a weak form of security in the l2tpv3 specification. 2763Their function is mostly to prevent misconfiguration. By default they are 32 2764bit. 2765@item cookie64 2766 Set cookie size to 64 bit instead of the default 32 2767@item counter=off 2768 Force a 'cut-down' L2TPv3 with no counter as in 2769draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2770@item pincounter=on 2771 Work around broken counter handling in peer. This may also help on 2772networks which have packet reorder. 2773@item offset=@var{offset} 2774 Add an extra offset between header and data 2775@end table 2776 2777For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to the bridge br-lan 2778on the remote Linux host 1.2.3.4: 2779@example 2780# Setup tunnel on linux host using raw ip as encapsulation 2781# on 1.2.3.4 2782ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \ 2783 encap udp udp_sport 16384 udp_dport 16384 2784ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \ 2785 0xFFFFFFFF peer_session_id 0xFFFFFFFF 2786ifconfig vmtunnel0 mtu 1500 2787ifconfig vmtunnel0 up 2788brctl addif br-lan vmtunnel0 2789 2790 2791# on 4.3.2.1 2792# launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 2793 2794@value{qemu_system} linux.img -device e1000,netdev=n1 \ 2795 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 2796 2797@end example 2798 2799@item -netdev vde,id=@var{id}[,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}] 2800Configure VDE backend to connect to PORT @var{n} of a vde switch running on host and 2801listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname} 2802and MODE @var{octalmode} to change default ownership and permissions for 2803communication port. This option is only available if QEMU has been compiled 2804with vde support enabled. 2805 2806Example: 2807@example 2808# launch vde switch 2809vde_switch -F -sock /tmp/myswitch 2810# launch QEMU instance 2811@value{qemu_system} linux.img -nic vde,sock=/tmp/myswitch 2812@end example 2813 2814@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n] 2815 2816Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should 2817be a unix domain socket backed one. The vhost-user uses a specifically defined 2818protocol to pass vhost ioctl replacement messages to an application on the other 2819end of the socket. On non-MSIX guests, the feature can be forced with 2820@var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to 2821be created for multiqueue vhost-user. 2822 2823Example: 2824@example 2825qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 2826 -numa node,memdev=mem \ 2827 -chardev socket,id=chr0,path=/path/to/socket \ 2828 -netdev type=vhost-user,id=net0,chardev=chr0 \ 2829 -device virtio-net-pci,netdev=net0 2830@end example 2831 2832@item -netdev hubport,id=@var{id},hubid=@var{hubid}[,netdev=@var{nd}] 2833 2834Create a hub port on the emulated hub with ID @var{hubid}. 2835 2836The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a 2837single netdev. Alternatively, you can also connect the hubport to another 2838netdev with ID @var{nd} by using the @option{netdev=@var{nd}} option. 2839 2840@item -net nic[,netdev=@var{nd}][,macaddr=@var{mac}][,model=@var{type}] [,name=@var{name}][,addr=@var{addr}][,vectors=@var{v}] 2841@findex -net 2842Legacy option to configure or create an on-board (or machine default) Network 2843Interface Card(NIC) and connect it either to the emulated hub with ID 0 (i.e. 2844the default hub), or to the netdev @var{nd}. 2845If @var{model} is omitted, then the default NIC model associated with 2846the machine type is used. Note that the default NIC model may change in 2847future QEMU releases, so it is highly recommended to always specify a model. 2848Optionally, the MAC address can be changed to @var{mac}, the device 2849address set to @var{addr} (PCI cards only), and a @var{name} can be 2850assigned for use in monitor commands. 2851Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors 2852that the card should have; this option currently only affects virtio cards; set 2853@var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single 2854NIC is created. QEMU can emulate several different models of network card. 2855Use @code{-net nic,model=help} for a list of available devices for your target. 2856 2857@item -net user|tap|bridge|socket|l2tpv3|vde[,...][,name=@var{name}] 2858Configure a host network backend (with the options corresponding to the same 2859@option{-netdev} option) and connect it to the emulated hub 0 (the default 2860hub). Use @var{name} to specify the name of the hub port. 2861ETEXI 2862 2863STEXI 2864@end table 2865ETEXI 2866DEFHEADING() 2867 2868DEFHEADING(Character device options:) 2869 2870DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 2871 "-chardev help\n" 2872 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2873 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n" 2874 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n" 2875 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 2876 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n" 2877 " [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n" 2878 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 2879 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n" 2880 " [,logfile=PATH][,logappend=on|off]\n" 2881 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2882 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 2883 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2884 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 2885 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2886 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2887#ifdef _WIN32 2888 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2889 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2890#else 2891 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2892 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 2893#endif 2894#ifdef CONFIG_BRLAPI 2895 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2896#endif 2897#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 2898 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 2899 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2900 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2901#endif 2902#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 2903 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2904 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2905#endif 2906#if defined(CONFIG_SPICE) 2907 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 2908 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 2909#endif 2910 , QEMU_ARCH_ALL 2911) 2912 2913STEXI 2914 2915The general form of a character device option is: 2916@table @option 2917@item -chardev @var{backend},id=@var{id}[,mux=on|off][,@var{options}] 2918@findex -chardev 2919Backend is one of: 2920@option{null}, 2921@option{socket}, 2922@option{udp}, 2923@option{msmouse}, 2924@option{vc}, 2925@option{ringbuf}, 2926@option{file}, 2927@option{pipe}, 2928@option{console}, 2929@option{serial}, 2930@option{pty}, 2931@option{stdio}, 2932@option{braille}, 2933@option{tty}, 2934@option{parallel}, 2935@option{parport}, 2936@option{spicevmc}, 2937@option{spiceport}. 2938The specific backend will determine the applicable options. 2939 2940Use @code{-chardev help} to print all available chardev backend types. 2941 2942All devices must have an id, which can be any string up to 127 characters long. 2943It is used to uniquely identify this device in other command line directives. 2944 2945A character device may be used in multiplexing mode by multiple front-ends. 2946Specify @option{mux=on} to enable this mode. 2947A multiplexer is a "1:N" device, and here the "1" end is your specified chardev 2948backend, and the "N" end is the various parts of QEMU that can talk to a chardev. 2949If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will 2950create a multiplexer with your specified ID, and you can then configure multiple 2951front ends to use that chardev ID for their input/output. Up to four different 2952front ends can be connected to a single multiplexed chardev. (Without 2953multiplexing enabled, a chardev can only be used by a single front end.) 2954For instance you could use this to allow a single stdio chardev to be used by 2955two serial ports and the QEMU monitor: 2956 2957@example 2958-chardev stdio,mux=on,id=char0 \ 2959-mon chardev=char0,mode=readline \ 2960-serial chardev:char0 \ 2961-serial chardev:char0 2962@end example 2963 2964You can have more than one multiplexer in a system configuration; for instance 2965you could have a TCP port multiplexed between UART 0 and UART 1, and stdio 2966multiplexed between the QEMU monitor and a parallel port: 2967 2968@example 2969-chardev stdio,mux=on,id=char0 \ 2970-mon chardev=char0,mode=readline \ 2971-parallel chardev:char0 \ 2972-chardev tcp,...,mux=on,id=char1 \ 2973-serial chardev:char1 \ 2974-serial chardev:char1 2975@end example 2976 2977When you're using a multiplexed character device, some escape sequences are 2978interpreted in the input. @xref{mux_keys, Keys in the character backend 2979multiplexer}. 2980 2981Note that some other command line options may implicitly create multiplexed 2982character backends; for instance @option{-serial mon:stdio} creates a 2983multiplexed stdio backend connected to the serial port and the QEMU monitor, 2984and @option{-nographic} also multiplexes the console and the monitor to 2985stdio. 2986 2987There is currently no support for multiplexing in the other direction 2988(where a single QEMU front end takes input and output from multiple chardevs). 2989 2990Every backend supports the @option{logfile} option, which supplies the path 2991to a file to record all data transmitted via the backend. The @option{logappend} 2992option controls whether the log file will be truncated or appended to when 2993opened. 2994 2995@end table 2996 2997The available backends are: 2998 2999@table @option 3000@item -chardev null,id=@var{id} 3001A void device. This device will not emit any data, and will drop any data it 3002receives. The null backend does not take any options. 3003 3004@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}][,tls-authz=@var{id}] 3005 3006Create a two-way stream socket, which can be either a TCP or a unix socket. A 3007unix socket will be created if @option{path} is specified. Behaviour is 3008undefined if TCP options are specified for a unix socket. 3009 3010@option{server} specifies that the socket shall be a listening socket. 3011 3012@option{nowait} specifies that QEMU should not block waiting for a client to 3013connect to a listening socket. 3014 3015@option{telnet} specifies that traffic on the socket should interpret telnet 3016escape sequences. 3017 3018@option{websocket} specifies that the socket uses WebSocket protocol for 3019communication. 3020 3021@option{reconnect} sets the timeout for reconnecting on non-server sockets when 3022the remote end goes away. qemu will delay this many seconds and then attempt 3023to reconnect. Zero disables reconnecting, and is the default. 3024 3025@option{tls-creds} requests enablement of the TLS protocol for encryption, 3026and specifies the id of the TLS credentials to use for the handshake. The 3027credentials must be previously created with the @option{-object tls-creds} 3028argument. 3029 3030@option{tls-auth} provides the ID of the QAuthZ authorization object against 3031which the client's x509 distinguished name will be validated. This object is 3032only resolved at time of use, so can be deleted and recreated on the fly 3033while the chardev server is active. If missing, it will default to denying 3034access. 3035 3036TCP and unix socket options are given below: 3037 3038@table @option 3039 3040@item TCP options: port=@var{port}[,host=@var{host}][,to=@var{to}][,ipv4][,ipv6][,nodelay] 3041 3042@option{host} for a listening socket specifies the local address to be bound. 3043For a connecting socket species the remote host to connect to. @option{host} is 3044optional for listening sockets. If not specified it defaults to @code{0.0.0.0}. 3045 3046@option{port} for a listening socket specifies the local port to be bound. For a 3047connecting socket specifies the port on the remote host to connect to. 3048@option{port} can be given as either a port number or a service name. 3049@option{port} is required. 3050 3051@option{to} is only relevant to listening sockets. If it is specified, and 3052@option{port} cannot be bound, QEMU will attempt to bind to subsequent ports up 3053to and including @option{to} until it succeeds. @option{to} must be specified 3054as a port number. 3055 3056@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used. 3057If neither is specified the socket may use either protocol. 3058 3059@option{nodelay} disables the Nagle algorithm. 3060 3061@item unix options: path=@var{path} 3062 3063@option{path} specifies the local path of the unix socket. @option{path} is 3064required. 3065 3066@end table 3067 3068@item -chardev udp,id=@var{id}[,host=@var{host}],port=@var{port}[,localaddr=@var{localaddr}][,localport=@var{localport}][,ipv4][,ipv6] 3069 3070Sends all traffic from the guest to a remote host over UDP. 3071 3072@option{host} specifies the remote host to connect to. If not specified it 3073defaults to @code{localhost}. 3074 3075@option{port} specifies the port on the remote host to connect to. @option{port} 3076is required. 3077 3078@option{localaddr} specifies the local address to bind to. If not specified it 3079defaults to @code{0.0.0.0}. 3080 3081@option{localport} specifies the local port to bind to. If not specified any 3082available local port will be used. 3083 3084@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used. 3085If neither is specified the device may use either protocol. 3086 3087@item -chardev msmouse,id=@var{id} 3088 3089Forward QEMU's emulated msmouse events to the guest. @option{msmouse} does not 3090take any options. 3091 3092@item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]] 3093 3094Connect to a QEMU text console. @option{vc} may optionally be given a specific 3095size. 3096 3097@option{width} and @option{height} specify the width and height respectively of 3098the console, in pixels. 3099 3100@option{cols} and @option{rows} specify that the console be sized to fit a text 3101console with the given dimensions. 3102 3103@item -chardev ringbuf,id=@var{id}[,size=@var{size}] 3104 3105Create a ring buffer with fixed size @option{size}. 3106@var{size} must be a power of two and defaults to @code{64K}. 3107 3108@item -chardev file,id=@var{id},path=@var{path} 3109 3110Log all traffic received from the guest to a file. 3111 3112@option{path} specifies the path of the file to be opened. This file will be 3113created if it does not already exist, and overwritten if it does. @option{path} 3114is required. 3115 3116@item -chardev pipe,id=@var{id},path=@var{path} 3117 3118Create a two-way connection to the guest. The behaviour differs slightly between 3119Windows hosts and other hosts: 3120 3121On Windows, a single duplex pipe will be created at 3122@file{\\.pipe\@option{path}}. 3123 3124On other hosts, 2 pipes will be created called @file{@option{path}.in} and 3125@file{@option{path}.out}. Data written to @file{@option{path}.in} will be 3126received by the guest. Data written by the guest can be read from 3127@file{@option{path}.out}. QEMU will not create these fifos, and requires them to 3128be present. 3129 3130@option{path} forms part of the pipe path as described above. @option{path} is 3131required. 3132 3133@item -chardev console,id=@var{id} 3134 3135Send traffic from the guest to QEMU's standard output. @option{console} does not 3136take any options. 3137 3138@option{console} is only available on Windows hosts. 3139 3140@item -chardev serial,id=@var{id},path=@option{path} 3141 3142Send traffic from the guest to a serial device on the host. 3143 3144On Unix hosts serial will actually accept any tty device, 3145not only serial lines. 3146 3147@option{path} specifies the name of the serial device to open. 3148 3149@item -chardev pty,id=@var{id} 3150 3151Create a new pseudo-terminal on the host and connect to it. @option{pty} does 3152not take any options. 3153 3154@option{pty} is not available on Windows hosts. 3155 3156@item -chardev stdio,id=@var{id}[,signal=on|off] 3157Connect to standard input and standard output of the QEMU process. 3158 3159@option{signal} controls if signals are enabled on the terminal, that includes 3160exiting QEMU with the key sequence @key{Control-c}. This option is enabled by 3161default, use @option{signal=off} to disable it. 3162 3163@item -chardev braille,id=@var{id} 3164 3165Connect to a local BrlAPI server. @option{braille} does not take any options. 3166 3167@item -chardev tty,id=@var{id},path=@var{path} 3168 3169@option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and 3170DragonFlyBSD hosts. It is an alias for @option{serial}. 3171 3172@option{path} specifies the path to the tty. @option{path} is required. 3173 3174@item -chardev parallel,id=@var{id},path=@var{path} 3175@itemx -chardev parport,id=@var{id},path=@var{path} 3176 3177@option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts. 3178 3179Connect to a local parallel port. 3180 3181@option{path} specifies the path to the parallel port device. @option{path} is 3182required. 3183 3184@item -chardev spicevmc,id=@var{id},debug=@var{debug},name=@var{name} 3185 3186@option{spicevmc} is only available when spice support is built in. 3187 3188@option{debug} debug level for spicevmc 3189 3190@option{name} name of spice channel to connect to 3191 3192Connect to a spice virtual machine channel, such as vdiport. 3193 3194@item -chardev spiceport,id=@var{id},debug=@var{debug},name=@var{name} 3195 3196@option{spiceport} is only available when spice support is built in. 3197 3198@option{debug} debug level for spicevmc 3199 3200@option{name} name of spice port to connect to 3201 3202Connect to a spice port, allowing a Spice client to handle the traffic 3203identified by a name (preferably a fqdn). 3204ETEXI 3205 3206STEXI 3207@end table 3208ETEXI 3209DEFHEADING() 3210 3211#ifdef CONFIG_TPM 3212DEFHEADING(TPM device options:) 3213 3214DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3215 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3216 " use path to provide path to a character device; default is /dev/tpm0\n" 3217 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3218 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3219 "-tpmdev emulator,id=id,chardev=dev\n" 3220 " configure the TPM device using chardev backend\n", 3221 QEMU_ARCH_ALL) 3222STEXI 3223 3224The general form of a TPM device option is: 3225@table @option 3226 3227@item -tpmdev @var{backend},id=@var{id}[,@var{options}] 3228@findex -tpmdev 3229 3230The specific backend type will determine the applicable options. 3231The @code{-tpmdev} option creates the TPM backend and requires a 3232@code{-device} option that specifies the TPM frontend interface model. 3233 3234Use @code{-tpmdev help} to print all available TPM backend types. 3235 3236@end table 3237 3238The available backends are: 3239 3240@table @option 3241 3242@item -tpmdev passthrough,id=@var{id},path=@var{path},cancel-path=@var{cancel-path} 3243 3244(Linux-host only) Enable access to the host's TPM using the passthrough 3245driver. 3246 3247@option{path} specifies the path to the host's TPM device, i.e., on 3248a Linux host this would be @code{/dev/tpm0}. 3249@option{path} is optional and by default @code{/dev/tpm0} is used. 3250 3251@option{cancel-path} specifies the path to the host TPM device's sysfs 3252entry allowing for cancellation of an ongoing TPM command. 3253@option{cancel-path} is optional and by default QEMU will search for the 3254sysfs entry to use. 3255 3256Some notes about using the host's TPM with the passthrough driver: 3257 3258The TPM device accessed by the passthrough driver must not be 3259used by any other application on the host. 3260 3261Since the host's firmware (BIOS/UEFI) has already initialized the TPM, 3262the VM's firmware (BIOS/UEFI) will not be able to initialize the 3263TPM again and may therefore not show a TPM-specific menu that would 3264otherwise allow the user to configure the TPM, e.g., allow the user to 3265enable/disable or activate/deactivate the TPM. 3266Further, if TPM ownership is released from within a VM then the host's TPM 3267will get disabled and deactivated. To enable and activate the 3268TPM again afterwards, the host has to be rebooted and the user is 3269required to enter the firmware's menu to enable and activate the TPM. 3270If the TPM is left disabled and/or deactivated most TPM commands will fail. 3271 3272To create a passthrough TPM use the following two options: 3273@example 3274-tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3275@end example 3276Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by 3277@code{tpmdev=tpm0} in the device option. 3278 3279@item -tpmdev emulator,id=@var{id},chardev=@var{dev} 3280 3281(Linux-host only) Enable access to a TPM emulator using Unix domain socket based 3282chardev backend. 3283 3284@option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server. 3285 3286To create a TPM emulator backend device with chardev socket backend: 3287@example 3288 3289-chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3290 3291@end example 3292 3293ETEXI 3294 3295STEXI 3296@end table 3297ETEXI 3298DEFHEADING() 3299 3300#endif 3301 3302DEFHEADING(Linux/Multiboot boot specific:) 3303STEXI 3304 3305When using these options, you can use a given Linux or Multiboot 3306kernel without installing it in the disk image. It can be useful 3307for easier testing of various kernels. 3308 3309@table @option 3310ETEXI 3311 3312DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3313 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3314STEXI 3315@item -kernel @var{bzImage} 3316@findex -kernel 3317Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel 3318or in multiboot format. 3319ETEXI 3320 3321DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3322 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3323STEXI 3324@item -append @var{cmdline} 3325@findex -append 3326Use @var{cmdline} as kernel command line 3327ETEXI 3328 3329DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3330 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3331STEXI 3332@item -initrd @var{file} 3333@findex -initrd 3334Use @var{file} as initial ram disk. 3335 3336@item -initrd "@var{file1} arg=foo,@var{file2}" 3337 3338This syntax is only available with multiboot. 3339 3340Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the 3341first module. 3342ETEXI 3343 3344DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3345 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3346STEXI 3347@item -dtb @var{file} 3348@findex -dtb 3349Use @var{file} as a device tree binary (dtb) image and pass it to the kernel 3350on boot. 3351ETEXI 3352 3353STEXI 3354@end table 3355ETEXI 3356DEFHEADING() 3357 3358DEFHEADING(Debug/Expert options:) 3359STEXI 3360@table @option 3361ETEXI 3362 3363DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3364 "-fw_cfg [name=]<name>,file=<file>\n" 3365 " add named fw_cfg entry with contents from file\n" 3366 "-fw_cfg [name=]<name>,string=<str>\n" 3367 " add named fw_cfg entry with contents from string\n", 3368 QEMU_ARCH_ALL) 3369STEXI 3370 3371@item -fw_cfg [name=]@var{name},file=@var{file} 3372@findex -fw_cfg 3373Add named fw_cfg entry with contents from file @var{file}. 3374 3375@item -fw_cfg [name=]@var{name},string=@var{str} 3376Add named fw_cfg entry with contents from string @var{str}. 3377 3378The terminating NUL character of the contents of @var{str} will not be 3379included as part of the fw_cfg item data. To insert contents with 3380embedded NUL characters, you have to use the @var{file} parameter. 3381 3382The fw_cfg entries are passed by QEMU through to the guest. 3383 3384Example: 3385@example 3386 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3387@end example 3388creates an fw_cfg entry named opt/com.mycompany/blob with contents 3389from ./my_blob.bin. 3390 3391ETEXI 3392 3393DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3394 "-serial dev redirect the serial port to char device 'dev'\n", 3395 QEMU_ARCH_ALL) 3396STEXI 3397@item -serial @var{dev} 3398@findex -serial 3399Redirect the virtual serial port to host character device 3400@var{dev}. The default device is @code{vc} in graphical mode and 3401@code{stdio} in non graphical mode. 3402 3403This option can be used several times to simulate up to 4 serial 3404ports. 3405 3406Use @code{-serial none} to disable all serial ports. 3407 3408Available character devices are: 3409@table @option 3410@item vc[:@var{W}x@var{H}] 3411Virtual console. Optionally, a width and height can be given in pixel with 3412@example 3413vc:800x600 3414@end example 3415It is also possible to specify width or height in characters: 3416@example 3417vc:80Cx24C 3418@end example 3419@item pty 3420[Linux only] Pseudo TTY (a new PTY is automatically allocated) 3421@item none 3422No device is allocated. 3423@item null 3424void device 3425@item chardev:@var{id} 3426Use a named character device defined with the @code{-chardev} option. 3427@item /dev/XXX 3428[Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port 3429parameters are set according to the emulated ones. 3430@item /dev/parport@var{N} 3431[Linux only, parallel port only] Use host parallel port 3432@var{N}. Currently SPP and EPP parallel port features can be used. 3433@item file:@var{filename} 3434Write output to @var{filename}. No character can be read. 3435@item stdio 3436[Unix only] standard input/output 3437@item pipe:@var{filename} 3438name pipe @var{filename} 3439@item COM@var{n} 3440[Windows only] Use host serial port @var{n} 3441@item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}] 3442This implements UDP Net Console. 3443When @var{remote_host} or @var{src_ip} are not specified 3444they default to @code{0.0.0.0}. 3445When not using a specified @var{src_port} a random port is automatically chosen. 3446 3447If you just want a simple readonly console you can use @code{netcat} or 3448@code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as: 3449@code{nc -u -l -p 4555}. Any time QEMU writes something to that port it 3450will appear in the netconsole session. 3451 3452If you plan to send characters back via netconsole or you want to stop 3453and start QEMU a lot of times, you should have QEMU use the same 3454source port each time by using something like @code{-serial 3455udp::4555@@:4556} to QEMU. Another approach is to use a patched 3456version of netcat which can listen to a TCP port and send and receive 3457characters via udp. If you have a patched version of netcat which 3458activates telnet remote echo and single char transfer, then you can 3459use the following options to set up a netcat redirector to allow 3460telnet on port 5555 to access the QEMU port. 3461@table @code 3462@item QEMU Options: 3463-serial udp::4555@@:4556 3464@item netcat options: 3465-u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3466@item telnet options: 3467localhost 5555 3468@end table 3469 3470@item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}] 3471The TCP Net Console has two modes of operation. It can send the serial 3472I/O to a location or wait for a connection from a location. By default 3473the TCP Net Console is sent to @var{host} at the @var{port}. If you use 3474the @var{server} option QEMU will wait for a client socket application 3475to connect to the port before continuing, unless the @code{nowait} 3476option was specified. The @code{nodelay} option disables the Nagle buffering 3477algorithm. The @code{reconnect} option only applies if @var{noserver} is 3478set, if the connection goes down it will attempt to reconnect at the 3479given interval. If @var{host} is omitted, 0.0.0.0 is assumed. Only 3480one TCP connection at a time is accepted. You can use @code{telnet} to 3481connect to the corresponding character device. 3482@table @code 3483@item Example to send tcp console to 192.168.0.2 port 4444 3484-serial tcp:192.168.0.2:4444 3485@item Example to listen and wait on port 4444 for connection 3486-serial tcp::4444,server 3487@item Example to not wait and listen on ip 192.168.0.100 port 4444 3488-serial tcp:192.168.0.100:4444,server,nowait 3489@end table 3490 3491@item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay] 3492The telnet protocol is used instead of raw tcp sockets. The options 3493work the same as if you had specified @code{-serial tcp}. The 3494difference is that the port acts like a telnet server or client using 3495telnet option negotiation. This will also allow you to send the 3496MAGIC_SYSRQ sequence if you use a telnet that supports sending the break 3497sequence. Typically in unix telnet you do it with Control-] and then 3498type "send break" followed by pressing the enter key. 3499 3500@item websocket:@var{host}:@var{port},server[,nowait][,nodelay] 3501The WebSocket protocol is used instead of raw tcp socket. The port acts as 3502a WebSocket server. Client mode is not supported. 3503 3504@item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}] 3505A unix domain socket is used instead of a tcp socket. The option works the 3506same as if you had specified @code{-serial tcp} except the unix domain socket 3507@var{path} is used for connections. 3508 3509@item mon:@var{dev_string} 3510This is a special option to allow the monitor to be multiplexed onto 3511another serial port. The monitor is accessed with key sequence of 3512@key{Control-a} and then pressing @key{c}. 3513@var{dev_string} should be any one of the serial devices specified 3514above. An example to multiplex the monitor onto a telnet server 3515listening on port 4444 would be: 3516@table @code 3517@item -serial mon:telnet::4444,server,nowait 3518@end table 3519When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate 3520QEMU any more but will be passed to the guest instead. 3521 3522@item braille 3523Braille device. This will use BrlAPI to display the braille output on a real 3524or fake device. 3525 3526@item msmouse 3527Three button serial mouse. Configure the guest to use Microsoft protocol. 3528@end table 3529ETEXI 3530 3531DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3532 "-parallel dev redirect the parallel port to char device 'dev'\n", 3533 QEMU_ARCH_ALL) 3534STEXI 3535@item -parallel @var{dev} 3536@findex -parallel 3537Redirect the virtual parallel port to host device @var{dev} (same 3538devices as the serial port). On Linux hosts, @file{/dev/parportN} can 3539be used to use hardware devices connected on the corresponding host 3540parallel port. 3541 3542This option can be used several times to simulate up to 3 parallel 3543ports. 3544 3545Use @code{-parallel none} to disable all parallel ports. 3546ETEXI 3547 3548DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3549 "-monitor dev redirect the monitor to char device 'dev'\n", 3550 QEMU_ARCH_ALL) 3551STEXI 3552@item -monitor @var{dev} 3553@findex -monitor 3554Redirect the monitor to host device @var{dev} (same devices as the 3555serial port). 3556The default device is @code{vc} in graphical mode and @code{stdio} in 3557non graphical mode. 3558Use @code{-monitor none} to disable the default monitor. 3559ETEXI 3560DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3561 "-qmp dev like -monitor but opens in 'control' mode\n", 3562 QEMU_ARCH_ALL) 3563STEXI 3564@item -qmp @var{dev} 3565@findex -qmp 3566Like -monitor but opens in 'control' mode. 3567ETEXI 3568DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3569 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3570 QEMU_ARCH_ALL) 3571STEXI 3572@item -qmp-pretty @var{dev} 3573@findex -qmp-pretty 3574Like -qmp but uses pretty JSON formatting. 3575ETEXI 3576 3577DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3578 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3579STEXI 3580@item -mon [chardev=]name[,mode=readline|control][,pretty[=on|off]] 3581@findex -mon 3582Setup monitor on chardev @var{name}. @code{pretty} turns on JSON pretty printing 3583easing human reading and debugging. 3584ETEXI 3585 3586DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3587 "-debugcon dev redirect the debug console to char device 'dev'\n", 3588 QEMU_ARCH_ALL) 3589STEXI 3590@item -debugcon @var{dev} 3591@findex -debugcon 3592Redirect the debug console to host device @var{dev} (same devices as the 3593serial port). The debug console is an I/O port which is typically port 35940xe9; writing to that I/O port sends output to this device. 3595The default device is @code{vc} in graphical mode and @code{stdio} in 3596non graphical mode. 3597ETEXI 3598 3599DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3600 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3601STEXI 3602@item -pidfile @var{file} 3603@findex -pidfile 3604Store the QEMU process PID in @var{file}. It is useful if you launch QEMU 3605from a script. 3606ETEXI 3607 3608DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3609 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3610STEXI 3611@item -singlestep 3612@findex -singlestep 3613Run the emulation in single step mode. 3614ETEXI 3615 3616DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3617 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3618 QEMU_ARCH_ALL) 3619STEXI 3620@item --preconfig 3621@findex --preconfig 3622Pause QEMU for interactive configuration before the machine is created, 3623which allows querying and configuring properties that will affect 3624machine initialization. Use QMP command 'x-exit-preconfig' to exit 3625the preconfig state and move to the next state (i.e. run guest if -S 3626isn't used or pause the second time if -S is used). This option is 3627experimental. 3628ETEXI 3629 3630DEF("S", 0, QEMU_OPTION_S, \ 3631 "-S freeze CPU at startup (use 'c' to start execution)\n", 3632 QEMU_ARCH_ALL) 3633STEXI 3634@item -S 3635@findex -S 3636Do not start CPU at startup (you must type 'c' in the monitor). 3637ETEXI 3638 3639DEF("realtime", HAS_ARG, QEMU_OPTION_realtime, 3640 "-realtime [mlock=on|off]\n" 3641 " run qemu with realtime features\n" 3642 " mlock=on|off controls mlock support (default: on)\n", 3643 QEMU_ARCH_ALL) 3644STEXI 3645@item -realtime mlock=on|off 3646@findex -realtime 3647Run qemu with realtime features. 3648mlocking qemu and guest memory can be enabled via @option{mlock=on} 3649(enabled by default). 3650ETEXI 3651 3652DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3653 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3654 " run qemu with overcommit hints\n" 3655 " mem-lock=on|off controls memory lock support (default: off)\n" 3656 " cpu-pm=on|off controls cpu power management (default: off)\n", 3657 QEMU_ARCH_ALL) 3658STEXI 3659@item -overcommit mem-lock=on|off 3660@item -overcommit cpu-pm=on|off 3661@findex -overcommit 3662Run qemu with hints about host resource overcommit. The default is 3663to assume that host overcommits all resources. 3664 3665Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled 3666by default). This works when host memory is not overcommitted and reduces the 3667worst-case latency for guest. This is equivalent to @option{realtime}. 3668 3669Guest ability to manage power state of host cpus (increasing latency for other 3670processes on the same host cpu, but decreasing latency for guest) can be 3671enabled via @option{cpu-pm=on} (disabled by default). This works best when 3672host CPU is not overcommitted. When used, host estimates of CPU cycle and power 3673utilization will be incorrect, not taking into account guest idle time. 3674ETEXI 3675 3676DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3677 "-gdb dev wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL) 3678STEXI 3679@item -gdb @var{dev} 3680@findex -gdb 3681Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical 3682connections will likely be TCP-based, but also UDP, pseudo TTY, or even 3683stdio are reasonable use case. The latter is allowing to start QEMU from 3684within gdb and establish the connection via a pipe: 3685@example 3686(gdb) target remote | exec @value{qemu_system} -gdb stdio ... 3687@end example 3688ETEXI 3689 3690DEF("s", 0, QEMU_OPTION_s, \ 3691 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3692 QEMU_ARCH_ALL) 3693STEXI 3694@item -s 3695@findex -s 3696Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3697(@pxref{gdb_usage}). 3698ETEXI 3699 3700DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3701 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3702 QEMU_ARCH_ALL) 3703STEXI 3704@item -d @var{item1}[,...] 3705@findex -d 3706Enable logging of specified items. Use '-d help' for a list of log items. 3707ETEXI 3708 3709DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3710 "-D logfile output log to logfile (default stderr)\n", 3711 QEMU_ARCH_ALL) 3712STEXI 3713@item -D @var{logfile} 3714@findex -D 3715Output log in @var{logfile} instead of to stderr 3716ETEXI 3717 3718DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3719 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3720 QEMU_ARCH_ALL) 3721STEXI 3722@item -dfilter @var{range1}[,...] 3723@findex -dfilter 3724Filter debug output to that relevant to a range of target addresses. The filter 3725spec can be either @var{start}+@var{size}, @var{start}-@var{size} or 3726@var{start}..@var{end} where @var{start} @var{end} and @var{size} are the 3727addresses and sizes required. For example: 3728@example 3729 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3730@end example 3731Will dump output for any code in the 0x1000 sized block starting at 0x8000 and 3732the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized 3733block starting at 0xffffffc00005f000. 3734ETEXI 3735 3736DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3737 "-seed number seed the pseudo-random number generator\n", 3738 QEMU_ARCH_ALL) 3739STEXI 3740@item -seed @var{number} 3741@findex -seed 3742Force the guest to use a deterministic pseudo-random number generator, seeded 3743with @var{number}. This does not affect crypto routines within the host. 3744ETEXI 3745 3746DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3747 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3748 QEMU_ARCH_ALL) 3749STEXI 3750@item -L @var{path} 3751@findex -L 3752Set the directory for the BIOS, VGA BIOS and keymaps. 3753 3754To list all the data directories, use @code{-L help}. 3755ETEXI 3756 3757DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3758 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3759STEXI 3760@item -bios @var{file} 3761@findex -bios 3762Set the filename for the BIOS. 3763ETEXI 3764 3765DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3766 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3767STEXI 3768@item -enable-kvm 3769@findex -enable-kvm 3770Enable KVM full virtualization support. This option is only available 3771if KVM support is enabled when compiling. 3772ETEXI 3773 3774DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3775 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3776DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3777 "-xen-attach attach to existing xen domain\n" 3778 " libxl will use this when starting QEMU\n", 3779 QEMU_ARCH_ALL) 3780DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3781 "-xen-domid-restrict restrict set of available xen operations\n" 3782 " to specified domain id. (Does not affect\n" 3783 " xenpv machine type).\n", 3784 QEMU_ARCH_ALL) 3785STEXI 3786@item -xen-domid @var{id} 3787@findex -xen-domid 3788Specify xen guest domain @var{id} (XEN only). 3789@item -xen-attach 3790@findex -xen-attach 3791Attach to existing xen domain. 3792libxl will use this when starting QEMU (XEN only). 3793@findex -xen-domid-restrict 3794Restrict set of available xen operations to specified domain id (XEN only). 3795ETEXI 3796 3797DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 3798 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 3799STEXI 3800@item -no-reboot 3801@findex -no-reboot 3802Exit instead of rebooting. 3803ETEXI 3804 3805DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 3806 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 3807STEXI 3808@item -no-shutdown 3809@findex -no-shutdown 3810Don't exit QEMU on guest shutdown, but instead only stop the emulation. 3811This allows for instance switching to monitor to commit changes to the 3812disk image. 3813ETEXI 3814 3815DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 3816 "-loadvm [tag|id]\n" \ 3817 " start right away with a saved state (loadvm in monitor)\n", 3818 QEMU_ARCH_ALL) 3819STEXI 3820@item -loadvm @var{file} 3821@findex -loadvm 3822Start right away with a saved state (@code{loadvm} in monitor) 3823ETEXI 3824 3825#ifndef _WIN32 3826DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 3827 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 3828#endif 3829STEXI 3830@item -daemonize 3831@findex -daemonize 3832Daemonize the QEMU process after initialization. QEMU will not detach from 3833standard IO until it is ready to receive connections on any of its devices. 3834This option is a useful way for external programs to launch QEMU without having 3835to cope with initialization race conditions. 3836ETEXI 3837 3838DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 3839 "-option-rom rom load a file, rom, into the option ROM space\n", 3840 QEMU_ARCH_ALL) 3841STEXI 3842@item -option-rom @var{file} 3843@findex -option-rom 3844Load the contents of @var{file} as an option ROM. 3845This option is useful to load things like EtherBoot. 3846ETEXI 3847 3848DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 3849 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 3850 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 3851 QEMU_ARCH_ALL) 3852 3853STEXI 3854 3855@item -rtc [base=utc|localtime|@var{datetime}][,clock=host|rt|vm][,driftfix=none|slew] 3856@findex -rtc 3857Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current 3858UTC or local time, respectively. @code{localtime} is required for correct date in 3859MS-DOS or Windows. To start at a specific point in time, provide @var{datetime} in the 3860format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC. 3861 3862By default the RTC is driven by the host system time. This allows using of the 3863RTC as accurate reference clock inside the guest, specifically if the host 3864time is smoothly following an accurate external reference clock, e.g. via NTP. 3865If you want to isolate the guest time from the host, you can set @option{clock} 3866to @code{rt} instead, which provides a host monotonic clock if host support it. 3867To even prevent the RTC from progressing during suspension, you can set @option{clock} 3868to @code{vm} (virtual clock). @samp{clock=vm} is recommended especially in 3869icount mode in order to preserve determinism; however, note that in icount mode 3870the speed of the virtual clock is variable and can in general differ from the 3871host clock. 3872 3873Enable @option{driftfix} (i386 targets only) if you experience time drift problems, 3874specifically with Windows' ACPI HAL. This option will try to figure out how 3875many timer interrupts were not processed by the Windows guest and will 3876re-inject them. 3877ETEXI 3878 3879DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 3880 "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \ 3881 " enable virtual instruction counter with 2^N clock ticks per\n" \ 3882 " instruction, enable aligning the host and virtual clocks\n" \ 3883 " or disable real time cpu sleeping\n", QEMU_ARCH_ALL) 3884STEXI 3885@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}] 3886@findex -icount 3887Enable virtual instruction counter. The virtual cpu will execute one 3888instruction every 2^@var{N} ns of virtual time. If @code{auto} is specified 3889then the virtual cpu speed will be automatically adjusted to keep virtual 3890time within a few seconds of real time. 3891 3892When the virtual cpu is sleeping, the virtual time will advance at default 3893speed unless @option{sleep=on|off} is specified. 3894With @option{sleep=on|off}, the virtual time will jump to the next timer deadline 3895instantly whenever the virtual cpu goes to sleep mode and will not advance 3896if no timer is enabled. This behavior give deterministic execution times from 3897the guest point of view. 3898 3899Note that while this option can give deterministic behavior, it does not 3900provide cycle accurate emulation. Modern CPUs contain superscalar out of 3901order cores with complex cache hierarchies. The number of instructions 3902executed often has little or no correlation with actual performance. 3903 3904@option{align=on} will activate the delay algorithm which will try 3905to synchronise the host clock and the virtual clock. The goal is to 3906have a guest running at the real frequency imposed by the shift option. 3907Whenever the guest clock is behind the host clock and if 3908@option{align=on} is specified then we print a message to the user 3909to inform about the delay. 3910Currently this option does not work when @option{shift} is @code{auto}. 3911Note: The sync algorithm will work for those shift values for which 3912the guest clock runs ahead of the host clock. Typically this happens 3913when the shift value is high (how high depends on the host machine). 3914 3915When @option{rr} option is specified deterministic record/replay is enabled. 3916Replay log is written into @var{filename} file in record mode and 3917read from this file in replay mode. 3918 3919Option rrsnapshot is used to create new vm snapshot named @var{snapshot} 3920at the start of execution recording. In replay mode this option is used 3921to load the initial VM state. 3922ETEXI 3923 3924DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 3925 "-watchdog model\n" \ 3926 " enable virtual hardware watchdog [default=none]\n", 3927 QEMU_ARCH_ALL) 3928STEXI 3929@item -watchdog @var{model} 3930@findex -watchdog 3931Create a virtual hardware watchdog device. Once enabled (by a guest 3932action), the watchdog must be periodically polled by an agent inside 3933the guest or else the guest will be restarted. Choose a model for 3934which your guest has drivers. 3935 3936The @var{model} is the model of hardware watchdog to emulate. Use 3937@code{-watchdog help} to list available hardware models. Only one 3938watchdog can be enabled for a guest. 3939 3940The following models may be available: 3941@table @option 3942@item ib700 3943iBASE 700 is a very simple ISA watchdog with a single timer. 3944@item i6300esb 3945Intel 6300ESB I/O controller hub is a much more featureful PCI-based 3946dual-timer watchdog. 3947@item diag288 3948A virtual watchdog for s390x backed by the diagnose 288 hypercall 3949(currently KVM only). 3950@end table 3951ETEXI 3952 3953DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 3954 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 3955 " action when watchdog fires [default=reset]\n", 3956 QEMU_ARCH_ALL) 3957STEXI 3958@item -watchdog-action @var{action} 3959@findex -watchdog-action 3960 3961The @var{action} controls what QEMU will do when the watchdog timer 3962expires. 3963The default is 3964@code{reset} (forcefully reset the guest). 3965Other possible actions are: 3966@code{shutdown} (attempt to gracefully shutdown the guest), 3967@code{poweroff} (forcefully poweroff the guest), 3968@code{inject-nmi} (inject a NMI into the guest), 3969@code{pause} (pause the guest), 3970@code{debug} (print a debug message and continue), or 3971@code{none} (do nothing). 3972 3973Note that the @code{shutdown} action requires that the guest responds 3974to ACPI signals, which it may not be able to do in the sort of 3975situations where the watchdog would have expired, and thus 3976@code{-watchdog-action shutdown} is not recommended for production use. 3977 3978Examples: 3979 3980@table @code 3981@item -watchdog i6300esb -watchdog-action pause 3982@itemx -watchdog ib700 3983@end table 3984ETEXI 3985 3986DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 3987 "-echr chr set terminal escape character instead of ctrl-a\n", 3988 QEMU_ARCH_ALL) 3989STEXI 3990 3991@item -echr @var{numeric_ascii_value} 3992@findex -echr 3993Change the escape character used for switching to the monitor when using 3994monitor and serial sharing. The default is @code{0x01} when using the 3995@code{-nographic} option. @code{0x01} is equal to pressing 3996@code{Control-a}. You can select a different character from the ascii 3997control keys where 1 through 26 map to Control-a through Control-z. For 3998instance you could use the either of the following to change the escape 3999character to Control-t. 4000@table @code 4001@item -echr 0x14 4002@itemx -echr 20 4003@end table 4004ETEXI 4005 4006DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \ 4007 "-show-cursor show cursor\n", QEMU_ARCH_ALL) 4008STEXI 4009@item -show-cursor 4010@findex -show-cursor 4011Show cursor. 4012ETEXI 4013 4014DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \ 4015 "-tb-size n set TB size\n", QEMU_ARCH_ALL) 4016STEXI 4017@item -tb-size @var{n} 4018@findex -tb-size 4019Set TCG translation block cache size. Deprecated, use @samp{-accel tcg,tb-size=@var{n}} 4020instead. 4021ETEXI 4022 4023DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4024 "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \ 4025 "-incoming rdma:host:port[,ipv4][,ipv6]\n" \ 4026 "-incoming unix:socketpath\n" \ 4027 " prepare for incoming migration, listen on\n" \ 4028 " specified protocol and socket address\n" \ 4029 "-incoming fd:fd\n" \ 4030 "-incoming exec:cmdline\n" \ 4031 " accept incoming migration on given file descriptor\n" \ 4032 " or from given external command\n" \ 4033 "-incoming defer\n" \ 4034 " wait for the URI to be specified via migrate_incoming\n", 4035 QEMU_ARCH_ALL) 4036STEXI 4037@item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6] 4038@itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6] 4039@findex -incoming 4040Prepare for incoming migration, listen on a given tcp port. 4041 4042@item -incoming unix:@var{socketpath} 4043Prepare for incoming migration, listen on a given unix socket. 4044 4045@item -incoming fd:@var{fd} 4046Accept incoming migration from a given filedescriptor. 4047 4048@item -incoming exec:@var{cmdline} 4049Accept incoming migration as an output from specified external command. 4050 4051@item -incoming defer 4052Wait for the URI to be specified via migrate_incoming. The monitor can 4053be used to change settings (such as migration parameters) prior to issuing 4054the migrate_incoming to allow the migration to begin. 4055ETEXI 4056 4057DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4058 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4059STEXI 4060@item -only-migratable 4061@findex -only-migratable 4062Only allow migratable devices. Devices will not be allowed to enter an 4063unmigratable state. 4064ETEXI 4065 4066DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4067 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4068STEXI 4069@item -nodefaults 4070@findex -nodefaults 4071Don't create default devices. Normally, QEMU sets the default devices like serial 4072port, parallel port, virtual console, monitor device, VGA adapter, floppy and 4073CD-ROM drive and others. The @code{-nodefaults} option will disable all those 4074default devices. 4075ETEXI 4076 4077#ifndef _WIN32 4078DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4079 "-chroot dir chroot to dir just before starting the VM\n", 4080 QEMU_ARCH_ALL) 4081#endif 4082STEXI 4083@item -chroot @var{dir} 4084@findex -chroot 4085Immediately before starting guest execution, chroot to the specified 4086directory. Especially useful in combination with -runas. 4087ETEXI 4088 4089#ifndef _WIN32 4090DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4091 "-runas user change to user id user just before starting the VM\n" \ 4092 " user can be numeric uid:gid instead\n", 4093 QEMU_ARCH_ALL) 4094#endif 4095STEXI 4096@item -runas @var{user} 4097@findex -runas 4098Immediately before starting guest execution, drop root privileges, switching 4099to the specified user. 4100ETEXI 4101 4102DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4103 "-prom-env variable=value\n" 4104 " set OpenBIOS nvram variables\n", 4105 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4106STEXI 4107@item -prom-env @var{variable}=@var{value} 4108@findex -prom-env 4109Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only). 4110ETEXI 4111DEF("semihosting", 0, QEMU_OPTION_semihosting, 4112 "-semihosting semihosting mode\n", 4113 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4114 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2) 4115STEXI 4116@item -semihosting 4117@findex -semihosting 4118Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only). 4119ETEXI 4120DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4121 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4122 " semihosting configuration\n", 4123QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4124QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2) 4125STEXI 4126@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]] 4127@findex -semihosting-config 4128Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II only). 4129@table @option 4130@item target=@code{native|gdb|auto} 4131Defines where the semihosting calls will be addressed, to QEMU (@code{native}) 4132or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb} 4133during debug sessions and @code{native} otherwise. 4134@item chardev=@var{str1} 4135Send the output to a chardev backend output for native or auto output when not in gdb 4136@item arg=@var{str1},arg=@var{str2},... 4137Allows the user to pass input arguments, and can be used multiple times to build 4138up a list. The old-style @code{-kernel}/@code{-append} method of passing a 4139command line is still supported for backward compatibility. If both the 4140@code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are 4141specified, the former is passed to semihosting as it always takes precedence. 4142@end table 4143ETEXI 4144DEF("old-param", 0, QEMU_OPTION_old_param, 4145 "-old-param old param mode\n", QEMU_ARCH_ARM) 4146STEXI 4147@item -old-param 4148@findex -old-param (ARM) 4149Old param mode (ARM only). 4150ETEXI 4151 4152DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4153 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4154 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4155 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4156 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4157 " by the kernel, but typically no longer used by modern\n" \ 4158 " C library implementations.\n" \ 4159 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \ 4160 " its privileges by blacklisting all set*uid|gid system calls.\n" \ 4161 " The value 'children' will deny set*uid|gid system calls for\n" \ 4162 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4163 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4164 " blacklisting *fork and execve\n" \ 4165 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4166 QEMU_ARCH_ALL) 4167STEXI 4168@item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}] 4169@findex -sandbox 4170Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will 4171disable it. The default is 'off'. 4172@table @option 4173@item obsolete=@var{string} 4174Enable Obsolete system calls 4175@item elevateprivileges=@var{string} 4176Disable set*uid|gid system calls 4177@item spawn=@var{string} 4178Disable *fork and execve 4179@item resourcecontrol=@var{string} 4180Disable process affinity and schedular priority 4181@end table 4182ETEXI 4183 4184DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4185 "-readconfig <file>\n", QEMU_ARCH_ALL) 4186STEXI 4187@item -readconfig @var{file} 4188@findex -readconfig 4189Read device configuration from @var{file}. This approach is useful when you want to spawn 4190QEMU process with many command line options but you don't want to exceed the command line 4191character limit. 4192ETEXI 4193DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4194 "-writeconfig <file>\n" 4195 " read/write config file\n", QEMU_ARCH_ALL) 4196STEXI 4197@item -writeconfig @var{file} 4198@findex -writeconfig 4199Write device configuration to @var{file}. The @var{file} can be either filename to save 4200command line and device configuration into file or dash @code{-}) character to print the 4201output to stdout. This can be later used as input file for @code{-readconfig} option. 4202ETEXI 4203 4204DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4205 "-no-user-config\n" 4206 " do not load default user-provided config files at startup\n", 4207 QEMU_ARCH_ALL) 4208STEXI 4209@item -no-user-config 4210@findex -no-user-config 4211The @code{-no-user-config} option makes QEMU not load any of the user-provided 4212config files on @var{sysconfdir}. 4213ETEXI 4214 4215DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4216 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4217 " specify tracing options\n", 4218 QEMU_ARCH_ALL) 4219STEXI 4220HXCOMM This line is not accurate, as some sub-options are backend-specific but 4221HXCOMM HX does not support conditional compilation of text. 4222@item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}] 4223@findex -trace 4224@include qemu-option-trace.texi 4225ETEXI 4226DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4227 "-plugin [file=]<file>[,arg=<string>]\n" 4228 " load a plugin\n", 4229 QEMU_ARCH_ALL) 4230STEXI 4231@item -plugin file=@var{file}[,arg=@var{string}] 4232@findex -plugin 4233 4234Load a plugin. 4235 4236@table @option 4237@item file=@var{file} 4238Load the given plugin from a shared library file. 4239@item arg=@var{string} 4240Argument string passed to the plugin. (Can be given multiple times.) 4241@end table 4242ETEXI 4243 4244HXCOMM Internal use 4245DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4246DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4247 4248#ifdef __linux__ 4249DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4250 "-enable-fips enable FIPS 140-2 compliance\n", 4251 QEMU_ARCH_ALL) 4252#endif 4253STEXI 4254@item -enable-fips 4255@findex -enable-fips 4256Enable FIPS 140-2 compliance mode. 4257ETEXI 4258 4259HXCOMM Deprecated by -accel tcg 4260DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386) 4261 4262DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4263 "-msg timestamp[=on|off]\n" 4264 " control error message format\n" 4265 " timestamp=on enables timestamps (default: off)\n", 4266 QEMU_ARCH_ALL) 4267STEXI 4268@item -msg timestamp[=on|off] 4269@findex -msg 4270Control error message format. 4271@table @option 4272@item timestamp=on|off 4273Prefix messages with a timestamp. Default is off. 4274@end table 4275ETEXI 4276 4277DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4278 "-dump-vmstate <file>\n" 4279 " Output vmstate information in JSON format to file.\n" 4280 " Use the scripts/vmstate-static-checker.py file to\n" 4281 " check for possible regressions in migration code\n" 4282 " by comparing two such vmstate dumps.\n", 4283 QEMU_ARCH_ALL) 4284STEXI 4285@item -dump-vmstate @var{file} 4286@findex -dump-vmstate 4287Dump json-encoded vmstate information for current machine type to file 4288in @var{file} 4289ETEXI 4290 4291DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4292 "-enable-sync-profile\n" 4293 " enable synchronization profiling\n", 4294 QEMU_ARCH_ALL) 4295STEXI 4296@item -enable-sync-profile 4297@findex -enable-sync-profile 4298Enable synchronization profiling. 4299ETEXI 4300 4301STEXI 4302@end table 4303ETEXI 4304DEFHEADING() 4305 4306DEFHEADING(Generic object creation:) 4307STEXI 4308@table @option 4309ETEXI 4310 4311DEF("object", HAS_ARG, QEMU_OPTION_object, 4312 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4313 " create a new object of type TYPENAME setting properties\n" 4314 " in the order they are specified. Note that the 'id'\n" 4315 " property must be set. These objects are placed in the\n" 4316 " '/objects' path.\n", 4317 QEMU_ARCH_ALL) 4318STEXI 4319@item -object @var{typename}[,@var{prop1}=@var{value1},...] 4320@findex -object 4321Create a new object of type @var{typename} setting properties 4322in the order they are specified. Note that the 'id' 4323property must be set. These objects are placed in the 4324'/objects' path. 4325 4326@table @option 4327 4328@item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off},discard-data=@var{on|off},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},align=@var{align} 4329 4330Creates a memory file backend object, which can be used to back 4331the guest RAM with huge pages. 4332 4333The @option{id} parameter is a unique ID that will be used to reference this 4334memory region when configuring the @option{-numa} argument. 4335 4336The @option{size} option provides the size of the memory region, and accepts 4337common suffixes, eg @option{500M}. 4338 4339The @option{mem-path} provides the path to either a shared memory or huge page 4340filesystem mount. 4341 4342The @option{share} boolean option determines whether the memory 4343region is marked as private to QEMU, or shared. The latter allows 4344a co-operating external process to access the QEMU memory region. 4345 4346The @option{share} is also required for pvrdma devices due to 4347limitations in the RDMA API provided by Linux. 4348 4349Setting share=on might affect the ability to configure NUMA 4350bindings for the memory backend under some circumstances, see 4351Documentation/vm/numa_memory_policy.txt on the Linux kernel 4352source tree for additional details. 4353 4354Setting the @option{discard-data} boolean option to @var{on} 4355indicates that file contents can be destroyed when QEMU exits, 4356to avoid unnecessarily flushing data to the backing file. Note 4357that @option{discard-data} is only an optimization, and QEMU 4358might not discard file contents if it aborts unexpectedly or is 4359terminated using SIGKILL. 4360 4361The @option{merge} boolean option enables memory merge, also known as 4362MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for 4363memory deduplication. 4364 4365Setting the @option{dump} boolean option to @var{off} excludes the memory from 4366core dumps. This feature is also known as MADV_DONTDUMP. 4367 4368The @option{prealloc} boolean option enables memory preallocation. 4369 4370The @option{host-nodes} option binds the memory range to a list of NUMA host 4371nodes. 4372 4373The @option{policy} option sets the NUMA policy to one of the following values: 4374 4375@table @option 4376@item @var{default} 4377default host policy 4378 4379@item @var{preferred} 4380prefer the given host node list for allocation 4381 4382@item @var{bind} 4383restrict memory allocation to the given host node list 4384 4385@item @var{interleave} 4386interleave memory allocations across the given host node list 4387@end table 4388 4389The @option{align} option specifies the base address alignment when 4390QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg 4391@option{2M}. Some backend store specified by @option{mem-path} 4392requires an alignment different than the default one used by QEMU, eg 4393the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4394such cases, users can specify the required alignment via this option. 4395 4396The @option{pmem} option specifies whether the backing file specified 4397by @option{mem-path} is in host persistent memory that can be accessed 4398using the SNIA NVM programming model (e.g. Intel NVDIMM). 4399If @option{pmem} is set to 'on', QEMU will take necessary operations to 4400guarantee the persistence of its own writes to @option{mem-path} 4401(e.g. in vNVDIMM label emulation and live migration). 4402Also, we will map the backend-file with MAP_SYNC flag, which ensures the 4403file metadata is in sync for @option{mem-path} in case of host crash 4404or a power failure. MAP_SYNC requires support from both the host kernel 4405(since Linux kernel 4.15) and the filesystem of @option{mem-path} mounted 4406with DAX option. 4407 4408@item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} 4409 4410Creates a memory backend object, which can be used to back the guest RAM. 4411Memory backend objects offer more control than the @option{-m} option that is 4412traditionally used to define guest RAM. Please refer to 4413@option{memory-backend-file} for a description of the options. 4414 4415@item -object memory-backend-memfd,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},seal=@var{on|off},hugetlb=@var{on|off},hugetlbsize=@var{size} 4416 4417Creates an anonymous memory file backend object, which allows QEMU to 4418share the memory with an external process (e.g. when using 4419vhost-user). The memory is allocated with memfd and optional 4420sealing. (Linux only) 4421 4422The @option{seal} option creates a sealed-file, that will block 4423further resizing the memory ('on' by default). 4424 4425The @option{hugetlb} option specify the file to be created resides in 4426the hugetlbfs filesystem (since Linux 4.14). Used in conjunction with 4427the @option{hugetlb} option, the @option{hugetlbsize} option specify 4428the hugetlb page size on systems that support multiple hugetlb page 4429sizes (it must be a power of 2 value supported by the system). 4430 4431In some versions of Linux, the @option{hugetlb} option is incompatible 4432with the @option{seal} option (requires at least Linux 4.16). 4433 4434Please refer to @option{memory-backend-file} for a description of the 4435other options. 4436 4437The @option{share} boolean option is @var{on} by default with memfd. 4438 4439@item -object rng-builtin,id=@var{id} 4440 4441Creates a random number generator backend which obtains entropy from 4442QEMU builtin functions. The @option{id} parameter is a unique ID that 4443will be used to reference this entropy backend from the @option{virtio-rng} 4444device. By default, the @option{virtio-rng} device uses this RNG backend. 4445 4446@item -object rng-random,id=@var{id},filename=@var{/dev/random} 4447 4448Creates a random number generator backend which obtains entropy from 4449a device on the host. The @option{id} parameter is a unique ID that 4450will be used to reference this entropy backend from the @option{virtio-rng} 4451device. The @option{filename} parameter specifies which file to obtain 4452entropy from and if omitted defaults to @option{/dev/urandom}. 4453 4454@item -object rng-egd,id=@var{id},chardev=@var{chardevid} 4455 4456Creates a random number generator backend which obtains entropy from 4457an external daemon running on the host. The @option{id} parameter is 4458a unique ID that will be used to reference this entropy backend from 4459the @option{virtio-rng} device. The @option{chardev} parameter is 4460the unique ID of a character device backend that provides the connection 4461to the RNG daemon. 4462 4463@item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off} 4464 4465Creates a TLS anonymous credentials object, which can be used to provide 4466TLS support on network backends. The @option{id} parameter is a unique 4467ID which network backends will use to access the credentials. The 4468@option{endpoint} is either @option{server} or @option{client} depending 4469on whether the QEMU network backend that uses the credentials will be 4470acting as a client or as a server. If @option{verify-peer} is enabled 4471(the default) then once the handshake is completed, the peer credentials 4472will be verified, though this is a no-op for anonymous credentials. 4473 4474The @var{dir} parameter tells QEMU where to find the credential 4475files. For server endpoints, this directory may contain a file 4476@var{dh-params.pem} providing diffie-hellman parameters to use 4477for the TLS server. If the file is missing, QEMU will generate 4478a set of DH parameters at startup. This is a computationally 4479expensive operation that consumes random pool entropy, so it is 4480recommended that a persistent set of parameters be generated 4481upfront and saved. 4482 4483@item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}] 4484 4485Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide 4486TLS support on network backends. The @option{id} parameter is a unique 4487ID which network backends will use to access the credentials. The 4488@option{endpoint} is either @option{server} or @option{client} depending 4489on whether the QEMU network backend that uses the credentials will be 4490acting as a client or as a server. For clients only, @option{username} 4491is the username which will be sent to the server. If omitted 4492it defaults to ``qemu''. 4493 4494The @var{dir} parameter tells QEMU where to find the keys file. 4495It is called ``@var{dir}/keys.psk'' and contains ``username:key'' 4496pairs. This file can most easily be created using the GnuTLS 4497@code{psktool} program. 4498 4499For server endpoints, @var{dir} may also contain a file 4500@var{dh-params.pem} providing diffie-hellman parameters to use 4501for the TLS server. If the file is missing, QEMU will generate 4502a set of DH parameters at startup. This is a computationally 4503expensive operation that consumes random pool entropy, so it is 4504recommended that a persistent set of parameters be generated 4505up front and saved. 4506 4507@item -object tls-creds-x509,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},priority=@var{priority},verify-peer=@var{on|off},passwordid=@var{id} 4508 4509Creates a TLS anonymous credentials object, which can be used to provide 4510TLS support on network backends. The @option{id} parameter is a unique 4511ID which network backends will use to access the credentials. The 4512@option{endpoint} is either @option{server} or @option{client} depending 4513on whether the QEMU network backend that uses the credentials will be 4514acting as a client or as a server. If @option{verify-peer} is enabled 4515(the default) then once the handshake is completed, the peer credentials 4516will be verified. With x509 certificates, this implies that the clients 4517must be provided with valid client certificates too. 4518 4519The @var{dir} parameter tells QEMU where to find the credential 4520files. For server endpoints, this directory may contain a file 4521@var{dh-params.pem} providing diffie-hellman parameters to use 4522for the TLS server. If the file is missing, QEMU will generate 4523a set of DH parameters at startup. This is a computationally 4524expensive operation that consumes random pool entropy, so it is 4525recommended that a persistent set of parameters be generated 4526upfront and saved. 4527 4528For x509 certificate credentials the directory will contain further files 4529providing the x509 certificates. The certificates must be stored 4530in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional), 4531@var{server-cert.pem} (only servers), @var{server-key.pem} (only servers), 4532@var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients). 4533 4534For the @var{server-key.pem} and @var{client-key.pem} files which 4535contain sensitive private keys, it is possible to use an encrypted 4536version by providing the @var{passwordid} parameter. This provides 4537the ID of a previously created @code{secret} object containing the 4538password for decryption. 4539 4540The @var{priority} parameter allows to override the global default 4541priority used by gnutls. This can be useful if the system administrator 4542needs to use a weaker set of crypto priorities for QEMU without 4543potentially forcing the weakness onto all applications. Or conversely 4544if one wants wants a stronger default for QEMU than for all other 4545applications, they can do this through this parameter. Its format is 4546a gnutls priority string as described at 4547@url{https://gnutls.org/manual/html_node/Priority-Strings.html}. 4548 4549@item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}] 4550 4551Interval @var{t} can't be 0, this filter batches the packet delivery: all 4552packets arriving in a given interval on netdev @var{netdevid} are delayed 4553until the end of the interval. Interval is in microseconds. 4554@option{status} is optional that indicate whether the netfilter is 4555on (enabled) or off (disabled), the default status for netfilter will be 'on'. 4556 4557queue @var{all|rx|tx} is an option that can be applied to any netfilter. 4558 4559@option{all}: the filter is attached both to the receive and the transmit 4560 queue of the netdev (default). 4561 4562@option{rx}: the filter is attached to the receive queue of the netdev, 4563 where it will receive packets sent to the netdev. 4564 4565@option{tx}: the filter is attached to the transmit queue of the netdev, 4566 where it will receive packets sent by the netdev. 4567 4568@item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support] 4569 4570filter-mirror on netdev @var{netdevid},mirror net packet to chardev@var{chardevid}, if it has the vnet_hdr_support flag, filter-mirror will mirror packet with vnet_hdr_len. 4571 4572@item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support] 4573 4574filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev 4575@var{chardevid},and redirect indev's packet to filter.if it has the vnet_hdr_support flag, 4576filter-redirector will redirect packet with vnet_hdr_len. 4577Create a filter-redirector we need to differ outdev id from indev id, id can not 4578be the same. we can just use indev or outdev, but at least one of indev or outdev 4579need to be specified. 4580 4581@item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},queue=@var{all|rx|tx},[vnet_hdr_support] 4582 4583Filter-rewriter is a part of COLO project.It will rewrite tcp packet to 4584secondary from primary to keep secondary tcp connection,and rewrite 4585tcp packet to primary from secondary make tcp packet can be handled by 4586client.if it has the vnet_hdr_support flag, we can parse packet with vnet header. 4587 4588usage: 4589colo secondary: 4590-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4591-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4592-object filter-rewriter,id=rew0,netdev=hn0,queue=all 4593 4594@item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}] 4595 4596Dump the network traffic on netdev @var{dev} to the file specified by 4597@var{filename}. At most @var{len} bytes (64k by default) per packet are stored. 4598The file format is libpcap, so it can be analyzed with tools such as tcpdump 4599or Wireshark. 4600 4601@item -object colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},outdev=@var{chardevid},iothread=@var{id}[,vnet_hdr_support][,notify_dev=@var{id}] 4602 4603Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with 4604secondary packet. If the packets are same, we will output primary 4605packet to outdev@var{chardevid}, else we will notify colo-frame 4606do checkpoint and send primary packet to outdev@var{chardevid}. 4607In order to improve efficiency, we need to put the task of comparison 4608in another thread. If it has the vnet_hdr_support flag, colo compare 4609will send/recv packet with vnet_hdr_len. 4610If you want to use Xen COLO, will need the notify_dev to notify Xen 4611colo-frame to do checkpoint. 4612 4613we must use it with the help of filter-mirror and filter-redirector. 4614 4615@example 4616 4617KVM COLO 4618 4619primary: 4620-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4621-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4622-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4623-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4624-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4625-chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4626-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4627-chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4628-object iothread,id=iothread1 4629-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4630-object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4631-object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4632-object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4633 4634secondary: 4635-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4636-device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4637-chardev socket,id=red0,host=3.3.3.3,port=9003 4638-chardev socket,id=red1,host=3.3.3.3,port=9004 4639-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4640-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4641 4642 4643Xen COLO 4644 4645primary: 4646-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4647-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4648-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4649-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4650-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4651-chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4652-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4653-chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4654-chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait 4655-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4656-object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4657-object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4658-object iothread,id=iothread1 4659-object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4660 4661secondary: 4662-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4663-device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4664-chardev socket,id=red0,host=3.3.3.3,port=9003 4665-chardev socket,id=red1,host=3.3.3.3,port=9004 4666-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4667-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4668 4669@end example 4670 4671If you want to know the detail of above command line, you can read 4672the colo-compare git log. 4673 4674@item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}] 4675 4676Creates a cryptodev backend which executes crypto opreation from 4677the QEMU cipher APIS. The @var{id} parameter is 4678a unique ID that will be used to reference this cryptodev backend from 4679the @option{virtio-crypto} device. The @var{queues} parameter is optional, 4680which specify the queue number of cryptodev backend, the default of 4681@var{queues} is 1. 4682 4683@example 4684 4685 # @value{qemu_system} \ 4686 [...] \ 4687 -object cryptodev-backend-builtin,id=cryptodev0 \ 4688 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \ 4689 [...] 4690@end example 4691 4692@item -object cryptodev-vhost-user,id=@var{id},chardev=@var{chardevid}[,queues=@var{queues}] 4693 4694Creates a vhost-user cryptodev backend, backed by a chardev @var{chardevid}. 4695The @var{id} parameter is a unique ID that will be used to reference this 4696cryptodev backend from the @option{virtio-crypto} device. 4697The chardev should be a unix domain socket backed one. The vhost-user uses 4698a specifically defined protocol to pass vhost ioctl replacement messages 4699to an application on the other end of the socket. 4700The @var{queues} parameter is optional, which specify the queue number 4701of cryptodev backend for multiqueue vhost-user, the default of @var{queues} is 1. 4702 4703@example 4704 4705 # @value{qemu_system} \ 4706 [...] \ 4707 -chardev socket,id=chardev0,path=/path/to/socket \ 4708 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \ 4709 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \ 4710 [...] 4711@end example 4712 4713@item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}] 4714@item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}] 4715 4716Defines a secret to store a password, encryption key, or some other sensitive 4717data. The sensitive data can either be passed directly via the @var{data} 4718parameter, or indirectly via the @var{file} parameter. Using the @var{data} 4719parameter is insecure unless the sensitive data is encrypted. 4720 4721The sensitive data can be provided in raw format (the default), or base64. 4722When encoded as JSON, the raw format only supports valid UTF-8 characters, 4723so base64 is recommended for sending binary data. QEMU will convert from 4724which ever format is provided to the format it needs internally. eg, an 4725RBD password can be provided in raw format, even though it will be base64 4726encoded when passed onto the RBD sever. 4727 4728For added protection, it is possible to encrypt the data associated with 4729a secret using the AES-256-CBC cipher. Use of encryption is indicated 4730by providing the @var{keyid} and @var{iv} parameters. The @var{keyid} 4731parameter provides the ID of a previously defined secret that contains 4732the AES-256 decryption key. This key should be 32-bytes long and be 4733base64 encoded. The @var{iv} parameter provides the random initialization 4734vector used for encryption of this particular secret and should be a 4735base64 encrypted string of the 16-byte IV. 4736 4737The simplest (insecure) usage is to provide the secret inline 4738 4739@example 4740 4741 # @value{qemu_system} -object secret,id=sec0,data=letmein,format=raw 4742 4743@end example 4744 4745The simplest secure usage is to provide the secret via a file 4746 4747 # printf "letmein" > mypasswd.txt 4748 # @value{qemu_system} -object secret,id=sec0,file=mypasswd.txt,format=raw 4749 4750For greater security, AES-256-CBC should be used. To illustrate usage, 4751consider the openssl command line tool which can encrypt the data. Note 4752that when encrypting, the plaintext must be padded to the cipher block 4753size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm. 4754 4755First a master key needs to be created in base64 encoding: 4756 4757@example 4758 # openssl rand -base64 32 > key.b64 4759 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 4760@end example 4761 4762Each secret to be encrypted needs to have a random initialization vector 4763generated. These do not need to be kept secret 4764 4765@example 4766 # openssl rand -base64 16 > iv.b64 4767 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 4768@end example 4769 4770The secret to be defined can now be encrypted, in this case we're 4771telling openssl to base64 encode the result, but it could be left 4772as raw bytes if desired. 4773 4774@example 4775 # SECRET=$(printf "letmein" | 4776 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 4777@end example 4778 4779When launching QEMU, create a master secret pointing to @code{key.b64} 4780and specify that to be used to decrypt the user password. Pass the 4781contents of @code{iv.b64} to the second secret 4782 4783@example 4784 # @value{qemu_system} \ 4785 -object secret,id=secmaster0,format=base64,file=key.b64 \ 4786 -object secret,id=sec0,keyid=secmaster0,format=base64,\ 4787 data=$SECRET,iv=$(<iv.b64) 4788@end example 4789 4790@item -object sev-guest,id=@var{id},cbitpos=@var{cbitpos},reduced-phys-bits=@var{val},[sev-device=@var{string},policy=@var{policy},handle=@var{handle},dh-cert-file=@var{file},session-file=@var{file}] 4791 4792Create a Secure Encrypted Virtualization (SEV) guest object, which can be used 4793to provide the guest memory encryption support on AMD processors. 4794 4795When memory encryption is enabled, one of the physical address bit (aka the 4796C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos} 4797is used to provide the C-bit position. The C-bit position is Host family dependent 4798hence user must provide this value. On EPYC, the value should be 47. 4799 4800When memory encryption is enabled, we loose certain bits in physical address space. 4801The @option{reduced-phys-bits} is used to provide the number of bits we loose in 4802physical address space. Similar to C-bit, the value is Host family dependent. 4803On EPYC, the value should be 5. 4804 4805The @option{sev-device} provides the device file to use for communicating with 4806the SEV firmware running inside AMD Secure Processor. The default device is 4807'/dev/sev'. If hardware supports memory encryption then /dev/sev devices are 4808created by CCP driver. 4809 4810The @option{policy} provides the guest policy to be enforced by the SEV firmware 4811and restrict what configuration and operational commands can be performed on this 4812guest by the hypervisor. The policy should be provided by the guest owner and is 4813bound to the guest and cannot be changed throughout the lifetime of the guest. 4814The default is 0. 4815 4816If guest @option{policy} allows sharing the key with another SEV guest then 4817@option{handle} can be use to provide handle of the guest from which to share 4818the key. 4819 4820The @option{dh-cert-file} and @option{session-file} provides the guest owner's 4821Public Diffie-Hillman key defined in SEV spec. The PDH and session parameters 4822are used for establishing a cryptographic session with the guest owner to 4823negotiate keys used for attestation. The file must be encoded in base64. 4824 4825e.g to launch a SEV guest 4826@example 4827 # @value{qemu_system_x86} \ 4828 ...... 4829 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \ 4830 -machine ...,memory-encryption=sev0 4831 ..... 4832 4833@end example 4834 4835 4836@item -object authz-simple,id=@var{id},identity=@var{string} 4837 4838Create an authorization object that will control access to network services. 4839 4840The @option{identity} parameter is identifies the user and its format 4841depends on the network service that authorization object is associated 4842with. For authorizing based on TLS x509 certificates, the identity must 4843be the x509 distinguished name. Note that care must be taken to escape 4844any commas in the distinguished name. 4845 4846An example authorization object to validate a x509 distinguished name 4847would look like: 4848@example 4849 # @value{qemu_system} \ 4850 ... 4851 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \ 4852 ... 4853@end example 4854 4855Note the use of quotes due to the x509 distinguished name containing 4856whitespace, and escaping of ','. 4857 4858@item -object authz-listfile,id=@var{id},filename=@var{path},refresh=@var{yes|no} 4859 4860Create an authorization object that will control access to network services. 4861 4862The @option{filename} parameter is the fully qualified path to a file 4863containing the access control list rules in JSON format. 4864 4865An example set of rules that match against SASL usernames might look 4866like: 4867 4868@example 4869 @{ 4870 "rules": [ 4871 @{ "match": "fred", "policy": "allow", "format": "exact" @}, 4872 @{ "match": "bob", "policy": "allow", "format": "exact" @}, 4873 @{ "match": "danb", "policy": "deny", "format": "glob" @}, 4874 @{ "match": "dan*", "policy": "allow", "format": "exact" @}, 4875 ], 4876 "policy": "deny" 4877 @} 4878@end example 4879 4880When checking access the object will iterate over all the rules and 4881the first rule to match will have its @option{policy} value returned 4882as the result. If no rules match, then the default @option{policy} 4883value is returned. 4884 4885The rules can either be an exact string match, or they can use the 4886simple UNIX glob pattern matching to allow wildcards to be used. 4887 4888If @option{refresh} is set to true the file will be monitored 4889and automatically reloaded whenever its content changes. 4890 4891As with the @code{authz-simple} object, the format of the identity 4892strings being matched depends on the network service, but is usually 4893a TLS x509 distinguished name, or a SASL username. 4894 4895An example authorization object to validate a SASL username 4896would look like: 4897@example 4898 # @value{qemu_system} \ 4899 ... 4900 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=yes 4901 ... 4902@end example 4903 4904@item -object authz-pam,id=@var{id},service=@var{string} 4905 4906Create an authorization object that will control access to network services. 4907 4908The @option{service} parameter provides the name of a PAM service to use 4909for authorization. It requires that a file @code{/etc/pam.d/@var{service}} 4910exist to provide the configuration for the @code{account} subsystem. 4911 4912An example authorization object to validate a TLS x509 distinguished 4913name would look like: 4914 4915@example 4916 # @value{qemu_system} \ 4917 ... 4918 -object authz-pam,id=auth0,service=qemu-vnc 4919 ... 4920@end example 4921 4922There would then be a corresponding config file for PAM at 4923@code{/etc/pam.d/qemu-vnc} that contains: 4924 4925@example 4926account requisite pam_listfile.so item=user sense=allow \ 4927 file=/etc/qemu/vnc.allow 4928@end example 4929 4930Finally the @code{/etc/qemu/vnc.allow} file would contain 4931the list of x509 distingished names that are permitted 4932access 4933 4934@example 4935CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 4936@end example 4937 4938@item -object iothread,id=@var{id},poll-max-ns=@var{poll-max-ns},poll-grow=@var{poll-grow},poll-shrink=@var{poll-shrink} 4939 4940Creates a dedicated event loop thread that devices can be assigned to. This is 4941known as an IOThread. By default device emulation happens in vCPU threads or 4942the main event loop thread. This can become a scalability bottleneck. 4943IOThreads allow device emulation and I/O to run on other host CPUs. 4944 4945The @option{id} parameter is a unique ID that will be used to reference this 4946IOThread from @option{-device ...,iothread=@var{id}}. Multiple devices can be 4947assigned to an IOThread. Note that not all devices support an 4948@option{iothread} parameter. 4949 4950The @code{query-iothreads} QMP command lists IOThreads and reports their thread 4951IDs so that the user can configure host CPU pinning/affinity. 4952 4953IOThreads use an adaptive polling algorithm to reduce event loop latency. 4954Instead of entering a blocking system call to monitor file descriptors and then 4955pay the cost of being woken up when an event occurs, the polling algorithm 4956spins waiting for events for a short time. The algorithm's default parameters 4957are suitable for many cases but can be adjusted based on knowledge of the 4958workload and/or host device latency. 4959 4960The @option{poll-max-ns} parameter is the maximum number of nanoseconds to busy 4961wait for events. Polling can be disabled by setting this value to 0. 4962 4963The @option{poll-grow} parameter is the multiplier used to increase the polling 4964time when the algorithm detects it is missing events due to not polling long 4965enough. 4966 4967The @option{poll-shrink} parameter is the divisor used to decrease the polling 4968time when the algorithm detects it is spending too long polling without 4969encountering events. 4970 4971The polling parameters can be modified at run-time using the @code{qom-set} command (where @code{iothread1} is the IOThread's @code{id}): 4972 4973@example 4974(qemu) qom-set /objects/iothread1 poll-max-ns 100000 4975@end example 4976 4977@end table 4978 4979ETEXI 4980 4981 4982HXCOMM This is the last statement. Insert new options before this line! 4983STEXI 4984@end table 4985ETEXI 4986
