1 HXCOMM Use
DEFHEADING() to define headings
in both help text and texi
2 HXCOMM Text between STEXI and ETEXI are copied to texi version and
3 HXCOMM discarded from C version
4 HXCOMM
DEF(option
, HAS_ARG
/0, opt_enum
, opt_help
, arch_mask
) is used to
5 HXCOMM construct option structures
, enums and help message
for specified
7 HXCOMM HXCOMM can be used
for comments
, discarded from both texi and C
9 DEFHEADING(Standard options
:)
14 DEF("help", 0, QEMU_OPTION_h
,
15 "-h or -help display this help and exit\n", QEMU_ARCH_ALL
)
22 DEF("version", 0, QEMU_OPTION_version
,
23 "-version display version information and exit\n", QEMU_ARCH_ALL
)
27 Display version information and exit
30 DEF("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",
47 @item
-machine
[type
=]@
var{name
}[,prop
=@
var{value
}[,...]]
49 Select the emulated machine by @
var{name
}. Use @code
{-machine help
} to list
52 For architectures which aim to support live migration compatibility
53 across releases
, each release will introduce a
new versioned machine
54 type
. 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
.
57 To allow live migration of guests from QEMU version
2.8.0, to QEMU
58 version
2.9.0, the
2.9.0 version must support the ``pc
-i440fx
-2.8''
59 and ``pc
-q35
-2.8'' machines too
. To allow users live migrating VMs
60 to skip multiple intermediate releases when upgrading
, new releases
61 of QEMU will support machine types from many previous versions
.
63 Supported machine properties are
:
65 @item accel
=@
var{accels1
}[:@
var{accels2
}[:...]]
66 This is used to enable an accelerator
. Depending on the target architecture
,
67 kvm
, xen
, hax
, hvf
, whpx or tcg can be available
. By
default, tcg is used
. If there is
68 more than one accelerator specified
, the next one is used
if the previous one
70 @item vmport
=on|off|auto
71 Enables emulation of VMWare IO port
, for vmmouse etc
. auto says to select the
72 value based on accel
. For accel
=xen the
default is off otherwise the
default
74 @item dump
-guest
-core
=on|off
75 Include guest memory
in a core dump
. The
default is on
.
76 @item mem
-merge
=on|off
77 Enables or disables memory merge support
. This feature
, when supported by
78 the host
, de
-duplicates identical memory pages among VMs instances
80 @item aes
-key
-wrap
=on|off
81 Enables or disables AES key wrapping support on s390
-ccw hosts
. This feature
82 controls whether AES wrapping keys will be created to allow
83 execution of AES cryptographic functions
. The
default is on
.
84 @item dea
-key
-wrap
=on|off
85 Enables or disables DEA key wrapping support on s390
-ccw hosts
. This feature
86 controls whether DEA wrapping keys will be created to allow
87 execution of DEA cryptographic functions
. The
default is on
.
89 Enables or disables NVDIMM support
. The
default is off
.
90 @item enforce
-config
-section
=on|off
91 If @option
{enforce
-config
-section
} is set to @
var{on
}, force migration
92 code to send configuration section even
if the machine
-type sets the
93 @option
{migration
.send
-configuration
} property to @
var{off
}.
94 NOTE
: this parameter is deprecated
. Please use @option
{-global
}
95 @option
{migration
.send
-configuration
}=@
var{on|off
} instead
.
96 @item memory
-encryption
=@
var{}
97 Memory encryption object to use
. The
default is none
.
99 Enables or disables ACPI Heterogeneous Memory Attribute
Table (HMAT
) support
.
104 HXCOMM Deprecated by
-machine
105 DEF("M", HAS_ARG
, QEMU_OPTION_M
, "", QEMU_ARCH_ALL
)
107 DEF("cpu", HAS_ARG
, QEMU_OPTION_cpu
,
108 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL
)
110 @item
-cpu @
var{model
}
112 Select CPU
model (@code
{-cpu help
} for list and additional feature selection
)
115 DEF("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
)
124 @item
-accel @
var{name
}[,prop
=@
var{value
}[,...]]
126 This is used to enable an accelerator
. Depending on the target architecture
,
127 kvm
, xen
, hax
, hvf
, whpx or tcg can be available
. By
default, tcg is used
. If there is
128 more than one accelerator specified
, the next one is used
if the previous one
131 @item igd
-passthru
=on|off
132 When Xen is
in use
, this option controls whether Intel integrated graphics
133 devices can be passed through to the
guest (default=off
)
134 @item kernel
-irqchip
=on|off|split
135 Controls KVM
in-kernel irqchip support
. The
default is full acceleration of the
136 interrupt controllers
. On x86
, split irqchip reduces the kernel attack
137 surface
, at a performance cost
for non
-MSI interrupts
. Disabling the
in-kernel
138 irqchip completely is not recommended except
for debugging purposes
.
139 @item kvm
-shadow
-mem
=size
140 Defines the size of the KVM shadow MMU
.
141 @item tb
-size
=@
var{n
}
142 Controls the
size (in MiB
) of the TCG translation block cache
.
143 @item thread
=single|multi
144 Controls number of TCG threads
. When the TCG is multi
-threaded there will be one
145 thread per vCPU therefor taking advantage of additional host cores
. The
default
146 is to enable multi
-threading where both the back
-end and front
-ends support it and
147 no incompatible TCG features have been
enabled (e
.g
. icount
/replay
).
151 DEF("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",
162 @item
-smp
[cpus
=]@
var{n
}[,cores
=@
var{cores
}][,threads
=@
var{threads
}][,dies
=dies
][,sockets
=@
var{sockets
}][,maxcpus
=@
var{maxcpus
}]
164 Simulate an SMP system with @
var{n
} CPUs
. On the PC target
, up to
255
165 CPUs are supported
. On Sparc32 target
, Linux limits the number of usable CPUs
167 For the PC target
, the number of @
var{cores
} per die
, the number of @
var{threads
}
168 per cores
, the number of @
var{dies
} per packages and the total number of
169 @
var{sockets
} can be specified
. Missing values will be computed
.
170 If 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
.
174 DEF("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",
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
}]
190 Define a NUMA node and assign RAM and VCPUs to it
.
191 Set the NUMA distance from a source node to a destination node
.
192 Set the ACPI Heterogeneous Memory Attributes
for the given nodes
.
194 Legacy 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
198 set of VCPUs can be represented by providing multiple @samp
{cpus
}
199 options
. If @samp
{cpus
} is omitted on all nodes
, VCPUs are automatically
202 For example
, the following option assigns VCPUs
0, 1, 2 and
5 to
205 -numa node
,cpus
=0-2,cpus
=5
208 @samp
{cpu
} option is a
new alternative to @samp
{cpus
} option
209 which uses @samp
{socket
-id|core
-id|thread
-id
} properties to assign
210 CPU objects to a @
var{node
} using topology layout properties of CPU
.
211 The set of properties is machine specific
, and depends on used
212 machine 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
215 will be assigned
, it
's required for @var{node} to be declared
216 with @samp{node} option before it's used with @samp
{cpu
} option
.
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
226 @samp
{mem
} assigns a given RAM amount to a node
. @samp
{memdev
}
227 assigns RAM from a given memory backend device to a node
. If
228 @samp
{mem
} and @samp
{memdev
} are omitted
in all nodes
, RAM is
229 split equally between them
.
231 @samp
{mem
} and @samp
{memdev
} are mutually exclusive
. Furthermore
,
232 if one node uses @samp
{memdev
}, all of them have to use it
.
234 @samp
{initiator
} is an additional option that points to an @
var{initiator
}
235 NUMA node that has best
performance (the lowest latency or largest bandwidth
)
236 to
this NUMA @
var{node
}. Note that
this option can be set only when
237 the machine property
'hmat' is set to
'on'.
239 Following example creates a machine with
2 NUMA nodes
, node
0 has CPU
.
240 node
1 has only memory
, and its initiator is node
0. Note that because
241 node
0 has CPU
, by
default the initiator of node
0 is itself and must be
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
255 @
var{source
} and @
var{destination
} are NUMA node IDs
.
256 @
var{distance
} is the NUMA distance from @
var{source
} to @
var{destination
}.
257 The distance from a node to itself is always
10. If any pair of nodes is
258 given a distance
, then all pairs must be given distances
. Although
, when
259 distances are only given
in one direction
for each pair of nodes
, then
260 the distances
in the opposite directions are assumed to be the same
. If
,
261 however
, an asymmetrical pair of distances is given
for even one node
262 pair
, then all node pairs must be provided distance values
for both
263 directions
, even when they are symmetrical
. When a node is unreachable
264 from another node
, set the pair
's distance to 255.
266 Note that the -@option{numa} option doesn't allocate any of the
267 specified resources
, it just assigns existing resources to NUMA
268 nodes
. This means that one still has to use the @option
{-m
},
269 @option
{-smp
} options to allocate RAM and VCPUs respectively
.
271 Use @samp
{hmat
-lb
} to set System Locality Latency and Bandwidth Information
272 between initiator and target NUMA nodes
in ACPI Heterogeneous Attribute Memory
Table (HMAT
).
273 Initiator NUMA node can create memory requests
, usually it has one or more processors
.
274 Target NUMA node contains addressable memory
.
276 In @samp
{hmat
-lb
} option
, @
var{node
} are NUMA node IDs
. @
var{hierarchy
} is the memory
277 hierarchy of the target NUMA node
: if @
var{hierarchy
} is
'memory', the structure
278 represents the memory performance
; if @
var{hierarchy
} is
'first-level|second-level|third-level',
279 this 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
:
281 if 'hierarchy' is
'memory', 'data-type' is
'access|read|write' latency or
'access|read|write'
282 bandwidth 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
284 target memory side cache
.
286 @
var{lat
} is latency value
in nanoseconds
. @
var{bw
} is bandwidth value
,
287 the possible value and units are NUM
[M|G|T
], mean that the bandwidth value are
288 NUM byte per
second (or MB
/s
, GB
/s or TB
/s depending on used suffix
).
289 Note that
if latency or bandwidth value is
0, means the corresponding latency or
290 bandwidth information is not provided
.
292 In @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
294 level described
in this structure
, note that the cache level
0 should not be used
295 with @samp
{hmat
-cache
} option
. @
var{associativity
} is the cache associativity
,
296 the 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
.
299 For example
, the following options describe
2 NUMA nodes
. Node
0 has
2 cpus and
300 a ram
, node
1 has only a ram
. The processors
in node
0 access memory
in node
301 0 with access
-latency
5 nanoseconds
, access
-bandwidth is
200 MB
/s
;
302 The processors
in NUMA node
0 access memory
in NUMA node
1 with access
-latency
10
303 nanoseconds
, access
-bandwidth is
100 MB
/s
.
304 And
for memory side cache information
, NUMA node
0 and
1 both have
1 level memory
305 cache
, size is
10KB
, policy is write
-back
, the cache Line size is
8 bytes
:
309 -object memory
-backend
-ram
,size
=1G
,id
=m0 \
310 -object memory
-backend
-ram
,size
=1G
,id
=m1 \
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
326 DEF("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
)
330 @item
-add
-fd fd
=@
var{fd
},set
=@
var{set
}[,opaque
=@
var{opaque
}]
333 Add a file descriptor to an fd set
. Valid options are
:
337 This option defines the file descriptor of which a duplicate is added to fd set
.
338 The file descriptor cannot be stdin
, stdout
, or stderr
.
340 This option defines the ID of the fd set to add the file descriptor to
.
341 @item opaque
=@
var{opaque
}
342 This option defines a free
-form string that can be used to describe @
var{fd
}.
345 You can open an image
using pre
-opened file descriptors from an fd set
:
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
354 DEF("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
)
359 @item
-set @
var{group
}.@
var{id
}.@
var{arg
}=@
var{value
}
361 Set parameter @
var{arg
} for item @
var{id
} of type @
var{group
}
364 DEF("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",
370 @item
-global @
var{driver
}.@
var{prop
}=@
var{value
}
371 @itemx
-global driver
=@
var{driver
},property
=@
var{property
},value
=@
var{value
}
373 Set
default value of @
var{driver
}'s property @var{prop} to @var{value}, e.g.:
376 @value{qemu_system_x86} -global ide-hd.physical_block_size=4096 disk-image.img
379 In particular, you can use this to set driver properties for devices which are
380 created automatically by the machine model. To create a device which is not
381 created automatically and set properties on it, use -@option{device}.
383 -global @var{driver}.@var{prop}=@var{value} is shorthand for -global
384 driver=@var{driver},property=@var{prop},value=@var{value}. The
385 longhand syntax works even when @var{driver} contains a dot.
388 DEF("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",
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]
399 Specify boot order @var{drives} as a string of drive letters. Valid
400 drive 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
402 from network adapter 1-4), hard disk boot is the default. To apply a
403 particular boot order only on the first startup, specify it via
404 @option{once}. Note that the @option{order} or @option{once} parameter
405 should not be used together with the @option{bootindex} property of
406 devices, since the firmware implementations normally do not support both
409 Interactive boot menus/prompts can be enabled via @option{menu=on} as far
410 as firmware/BIOS supports them. The default is non-interactive boot.
412 A splash picture could be passed to bios, enabling user to show it as logo,
413 when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS
414 supports them. Currently Seabios for X86 system support it.
415 limitation: The splash file could be a jpeg file or a BMP file in 24 BPP
416 format(true color). The resolution should be supported by the SVGA mode, so
417 the recommended is 320x240, 640x480, 800x640.
419 A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms
420 when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
421 reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
424 Do strict boot via @option{strict=on} as far as firmware/BIOS
425 supports it. This only effects when boot priority is changed by
426 bootindex options. The default is non-strict boot.
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
437 Note: The legacy format '-boot @var{drives}' is still supported but its
438 use is discouraged as it may be removed from future versions.
441 DEF("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",
450 @item -m [size=]@var{megs}[,slots=n,maxmem=size]
452 Sets guest startup RAM size to @var{megs} megabytes. Default is 128 MiB.
453 Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in
454 megabytes or gigabytes respectively. Optional pair @var{slots}, @var{maxmem}
455 could be used to set amount of hotpluggable memory slots and maximum amount of
456 memory. Note that @var{maxmem} must be aligned to the page size.
458 For example, the following command-line sets the guest startup RAM size to
459 1GB, creates 3 slots to hotplug additional memory and sets the maximum
460 memory the guest can reach to 4GB:
463 @value{qemu_system} -m 1G,slots=3,maxmem=4G
466 If @var{slots} and @var{maxmem} are not specified, memory hotplug won't
467 be enabled and the guest startup RAM will never increase.
470 DEF("mem
-path
", HAS_ARG, QEMU_OPTION_mempath,
471 "-mem
-path FILE provide backing storage
for guest RAM
\n", QEMU_ARCH_ALL)
473 @item -mem-path @var{path}
475 Allocate guest RAM from a temporarily created file in @var{path}.
478 DEF("mem
-prealloc
", 0, QEMU_OPTION_mem_prealloc,
479 "-mem
-prealloc preallocate guest
memory (use with
-mem
-path
)\n",
483 @findex -mem-prealloc
484 Preallocate memory when using -mem-path.
487 DEF("k
", HAS_ARG, QEMU_OPTION_k,
488 "-k language use keyboard
layout (for example
'fr' for French
)\n",
491 @item -k @var{language}
493 Use keyboard layout @var{language} (for example @code{fr} for
494 French). This option is only needed where it is not easy to get raw PC
495 keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses
496 display). You don't normally need to use it on PC/Linux or PC/Windows
499 The available layouts are:
501 ar de-ch es fo fr-ca hu ja mk no pt-br sv
502 da en-gb et fr fr-ch is lt nl pl ru th
503 de en-us fi fr-be hr it lv nl-be pt sl tr
506 The default is @code{en-us}.
510 HXCOMM Deprecated by -audiodev
511 DEF("audio
-help
", 0, QEMU_OPTION_audio_help,
512 "-audio
-help show
-audiodev equivalent of the currently specified audio settings
\n",
517 Will show the -audiodev equivalent of the currently specified
518 (deprecated) environment variables.
521 DEF("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"
543 #ifdef CONFIG_AUDIO_COREAUDIO
544 "-audiodev coreaudio
,id
=id
[,prop
[=value
][,...]]\n"
545 " in|out
.buffer
-count
= number of buffers
\n"
547 #ifdef CONFIG_AUDIO_DSOUND
548 "-audiodev dsound
,id
=id
[,prop
[=value
][,...]]\n"
549 " latency
= add extra latency to playback
in microseconds
\n"
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"
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"
566 #ifdef CONFIG_AUDIO_SDL
567 "-audiodev sdl
,id
=id
[,prop
[=value
][,...]]\n"
570 "-audiodev spice
,id
=id
[,prop
[=value
][,...]]\n"
572 "-audiodev wav
,id
=id
[,prop
[=value
][,...]]\n"
573 " path
= path of wav file to record
\n",
576 @item -audiodev [driver=]@var{driver},id=@var{id}[,@var{prop}[=@var{value}][,...]]
578 Adds a new audio backend @var{driver} identified by @var{id}. There are
579 global and driver specific properties. Some values can be set
580 differently for input and output, they're marked with @code{in|out.}.
581 You can set the input's property with @code{in.@var{prop}} and the
582 output's property with @code{out.@var{prop}}. For example:
584 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
585 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
588 NOTE: parameter validation is known to be incomplete, in many cases
589 specifying an invalid option causes QEMU to print an error message and
590 continue emulation without sound.
592 Valid global options are:
595 @item id=@var{identifier}
596 Identifies the audio backend.
598 @item timer-period=@var{period}
599 Sets the timer @var{period} used by the audio subsystem in microseconds.
600 Default is 10000 (10 ms).
602 @item in|out.mixing-engine=on|off
603 Use QEMU's mixing engine to mix all streams inside QEMU and convert
604 audio formats when not supported by the backend. When off,
605 @var{fixed-settings} must be off too. Note that disabling this option
606 means that the selected backend must support multiple streams and the
607 audio formats used by the virtual cards, otherwise you'll get no sound.
608 It's not recommended to disable this option unless you want to use 5.1
609 or 7.1 audio, as mixing engine only supports mono and stereo audio.
612 @item in|out.fixed-settings=on|off
613 Use fixed settings for host audio. When off, it will change based on
614 how the guest opens the sound card. In this case you must not specify
615 @var{frequency}, @var{channels} or @var{format}. Default is on.
617 @item in|out.frequency=@var{frequency}
618 Specify the @var{frequency} to use when using @var{fixed-settings}.
621 @item in|out.channels=@var{channels}
622 Specify the number of @var{channels} to use when using
623 @var{fixed-settings}. Default is 2 (stereo).
625 @item in|out.format=@var{format}
626 Specify the sample @var{format} to use when using @var{fixed-settings}.
627 Valid values are: @code{s8}, @code{s16}, @code{s32}, @code{u8},
628 @code{u16}, @code{u32}. Default is @code{s16}.
630 @item in|out.voices=@var{voices}
631 Specify the number of @var{voices} to use. Default is 1.
633 @item in|out.buffer-length=@var{usecs}
634 Sets the size of the buffer in microseconds.
638 @item -audiodev none,id=@var{id}[,@var{prop}[=@var{value}][,...]]
639 Creates a dummy backend that discards all outputs. This backend has no
640 backend specific properties.
642 @item -audiodev alsa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
643 Creates backend using the ALSA. This backend is only available on
646 ALSA specific options are:
650 @item in|out.dev=@var{device}
651 Specify the ALSA @var{device} to use for input and/or output. Default
654 @item in|out.period-length=@var{usecs}
655 Sets the period length in microseconds.
657 @item in|out.try-poll=on|off
658 Attempt to use poll mode with the device. Default is on.
660 @item threshold=@var{threshold}
661 Threshold (in microseconds) when playback starts. Default is 0.
665 @item -audiodev coreaudio,id=@var{id}[,@var{prop}[=@var{value}][,...]]
666 Creates a backend using Apple's Core Audio. This backend is only
667 available on Mac OS and only supports playback.
669 Core Audio specific options are:
673 @item in|out.buffer-count=@var{count}
674 Sets the @var{count} of the buffers.
678 @item -audiodev dsound,id=@var{id}[,@var{prop}[=@var{value}][,...]]
679 Creates a backend using Microsoft's DirectSound. This backend is only
680 available on Windows and only supports playback.
682 DirectSound specific options are:
686 @item latency=@var{usecs}
687 Add extra @var{usecs} microseconds latency to playback. Default is
692 @item -audiodev oss,id=@var{id}[,@var{prop}[=@var{value}][,...]]
693 Creates a backend using OSS. This backend is available on most
696 OSS specific options are:
700 @item in|out.dev=@var{device}
701 Specify the file name of the OSS @var{device} to use. Default is
704 @item in|out.buffer-count=@var{count}
705 Sets the @var{count} of the buffers.
707 @item in|out.try-poll=on|of
708 Attempt to use poll mode with the device. Default is on.
710 @item try-mmap=on|off
711 Try using memory mapped device access. Default is off.
713 @item exclusive=on|off
714 Open the device in exclusive mode (vmix won't work in this case).
717 @item dsp-policy=@var{policy}
718 Sets the timing policy (between 0 and 10, where smaller number means
719 smaller latency but higher CPU usage). Use -1 to use buffer sizes
720 specified by @code{buffer} and @code{buffer-count}. This option is
721 ignored if you do not have OSS 4. Default is 5.
725 @item -audiodev pa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
726 Creates a backend using PulseAudio. This backend is available on most
729 PulseAudio specific options are:
733 @item server=@var{server}
734 Sets the PulseAudio @var{server} to connect to.
736 @item in|out.name=@var{sink}
737 Use the specified source/sink for recording/playback.
739 @item in|out.latency=@var{usecs}
740 Desired latency in microseconds. The PulseAudio server will try to honor this
741 value but actual latencies may be lower or higher.
745 @item -audiodev sdl,id=@var{id}[,@var{prop}[=@var{value}][,...]]
746 Creates a backend using SDL. This backend is available on most systems,
747 but you should use your platform's native backend if possible. This
748 backend has no backend specific properties.
750 @item -audiodev spice,id=@var{id}[,@var{prop}[=@var{value}][,...]]
751 Creates a backend that sends audio through SPICE. This backend requires
752 @code{-spice} and automatically selected in that case, so usually you
753 can ignore this option. This backend has no backend specific
756 @item -audiodev wav,id=@var{id}[,@var{prop}[=@var{value}][,...]]
757 Creates a backend that writes audio to a WAV file.
759 Backend specific options are:
763 @item path=@var{path}
764 Write recorded audio into the specified file. Default is
770 DEF("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)
776 @item -soundhw @var{card1}[,@var{card2},...] or -soundhw all
778 Enable audio and selected sound hardware. Use 'help' to print all
779 available sound hardware. For 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
790 Note that Linux's i810_audio OSS kernel (for AC97) module might
791 require manually specifying clocking.
794 modprobe i810_audio clocking=48000
798 DEF("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",
806 @item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
808 Add device @var{driver}. @var{prop}=@var{value} sets driver
809 properties. Valid properties depend on the driver. To get help on
810 possible drivers and properties, use @code{-device help} and
811 @code{-device @var{driver},help}.
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}]
816 Add an IPMI BMC. This is a simulation of a hardware management
817 interface processor that normally sits on a system. It provides
818 a watchdog and the ability to reset and power control the system.
819 You need to connect this to an IPMI interface to make it useful
821 The IPMI slave address to use for the BMC. The default is 0x20.
822 This address is the BMC's address on the I2C network of management
823 controllers. If you don't know what this means, it is safe to ignore
828 The BMC id for interfaces to use this device.
829 @item slave_addr=@var{val}
830 Define slave address to use for the BMC. The default is 0x20.
831 @item sdrfile=@var{file}
832 file containing raw Sensor Data Records (SDR) data. The default is none.
833 @item fruareasize=@var{val}
834 size of a Field Replaceable Unit (FRU) area. The default is 1024.
835 @item frudatafile=@var{file}
836 file containing raw Field Replaceable Unit (FRU) inventory data. The default is none.
837 @item guid=@var{uuid}
838 value for the GUID for the BMC, in standard UUID format. If this is set,
839 get "Get GUID
" command to the BMC will return it. Otherwise "Get GUID
"
840 will return an error.
843 @item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}]
845 Add a connection to an external IPMI BMC simulator. Instead of
846 locally emulating the BMC like the above item, instead connect
847 to an external entity that provides the IPMI services.
849 A connection is made to an external BMC simulator. If you do this, it
850 is strongly recommended that you use the "reconnect
=" chardev option
851 to reconnect to the simulator if the connection is lost. Note that if
852 this is not used carefully, it can be a security issue, as the
853 interface has the ability to send resets, NMIs, and power off the VM.
854 It's best if QEMU makes a connection to an external simulator running
855 on a secure port on localhost, so neither the simulator nor QEMU is
856 exposed to any outside network.
858 See the "lanserv
/README
.vm
" file in the OpenIPMI library for more
859 details on the external interface.
861 @item -device isa-ipmi-kcs,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
863 Add a KCS IPMI interafce on the ISA bus. This also adds a
864 corresponding ACPI and SMBIOS entries, if appropriate.
868 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
869 @item ioport=@var{val}
870 Define the I/O address of the interface. The default is 0xca0 for KCS.
872 Define the interrupt to use. The default is 5. To disable interrupts,
876 @item -device isa-ipmi-bt,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
878 Like the KCS interface, but defines a BT interface. The default port is
879 0xe4 and the default interrupt is 5.
883 DEF("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",
891 @item -name @var{name}
893 Sets the @var{name} of the guest.
894 This name will be displayed in the SDL window caption.
895 The @var{name} will also be used for the VNC server.
896 Also optionally set the top visible process name in Linux.
897 Naming of individual threads can also be enabled on Linux to aid debugging.
900 DEF("uuid
", HAS_ARG, QEMU_OPTION_uuid,
901 "-uuid
%08x
-%04x
-%04x
-%04x
-%012x
\n"
902 " specify machine UUID
\n", QEMU_ARCH_ALL)
904 @item -uuid @var{uuid}
914 DEFHEADING(Block device options:)
919 DEF("fda
", HAS_ARG, QEMU_OPTION_fda,
920 "-fda
/-fdb file use
'file' as floppy disk
0/1 image
\n", QEMU_ARCH_ALL)
921 DEF("fdb
", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
923 @item -fda @var{file}
924 @itemx -fdb @var{file}
927 Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}).
930 DEF("hda
", HAS_ARG, QEMU_OPTION_hda,
931 "-hda
/-hdb file use
'file' as IDE hard disk
0/1 image
\n", QEMU_ARCH_ALL)
932 DEF("hdb
", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
933 DEF("hdc
", HAS_ARG, QEMU_OPTION_hdc,
934 "-hdc
/-hdd file use
'file' as IDE hard disk
2/3 image
\n", QEMU_ARCH_ALL)
935 DEF("hdd
", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
937 @item -hda @var{file}
938 @itemx -hdb @var{file}
939 @itemx -hdc @var{file}
940 @itemx -hdd @var{file}
945 Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).
948 DEF("cdrom
", HAS_ARG, QEMU_OPTION_cdrom,
949 "-cdrom file use
'file' as IDE cdrom
image (cdrom is ide1 master
)\n",
952 @item -cdrom @var{file}
954 Use @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
956 using @file{/dev/cdrom} as filename.
959 DEF("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)
967 @item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]]
970 Define a new block driver node. Some of the options apply to all block drivers,
971 other options are only accepted for a specific block driver. See below for a
972 list of generic options and options for the most common block drivers.
974 Options that expect a reference to another node (e.g. @code{file}) can be
975 given 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
977 for the referenced node after a dot (file.filename=@var{path},file.aio=native).
979 A block driver node created with @option{-blockdev} can be used for a guest
980 device by specifying its node name for the @code{drive} property in a
981 @option{-device} argument that defines a block device.
984 @item Valid options for any block driver node:
988 Specifies the block driver to use for the given node.
990 This defines the name of the block driver node by which it will be referenced
991 later. The name must be unique, i.e. it must not match the name of a different
992 block driver node, or (if you use @option{-drive} as well) the ID of a drive.
994 If no node name is specified, it is automatically generated. The generated node
995 name is not intended to be predictable and changes between QEMU invocations.
996 For the top level, an explicit node name must be specified.
998 Open the node read-only. Guest write attempts will fail.
1000 Note that some block drivers support only read-only access, either generally or
1001 in certain configurations. In this case, the default value
1002 @option{read-only=off} does not work and the option must be specified
1004 @item auto-read-only
1005 If @option{auto-read-only=on} is set, QEMU may fall back to read-only usage
1006 even when @option{read-only=off} is requested, or even switch between modes as
1007 needed, e.g. depending on whether the image file is writable or whether a
1008 writing user is attached to the node.
1010 Override the image locking system of QEMU by forcing the node to utilize
1011 weaker shared access for permissions where it would normally request exclusive
1012 access. When there is the potential for multiple instances to have the same
1013 file open (whether this invocation of QEMU is the first or the second
1014 instance), both instances must permit shared access for the second instance to
1015 succeed at opening the file.
1017 Enabling @option{force-share=on} requires @option{read-only=on}.
1019 The host page cache can be avoided with @option{cache.direct=on}. This will
1020 attempt to do disk IO directly to the guest's memory. QEMU may still perform an
1021 internal copy of the data.
1022 @item cache.no-flush
1023 In 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
1025 any data to the disk but can instead keep things in cache. If anything goes
1026 wrong, like your host losing power, the disk storage getting disconnected
1027 accidentally, 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
1030 whether @code{discard} (also known as @code{trim} or @code{unmap}) requests are
1031 ignored or passed to the filesystem. Some machine types may not support
1033 @item detect-zeroes=@var{detect-zeroes}
1034 @var{detect-zeroes} is "off
", "on
" or "unmap
" and enables the automatic
1035 conversion of plain zero writes by the OS to driver specific optimized
1036 zero write commands. You may even choose "unmap
" if @var{discard} is set
1037 to "unmap
" to allow a zero write to be converted to an @code{unmap} operation.
1040 @item Driver-specific options for @code{file}
1042 This is the protocol-level block driver for accessing regular files.
1046 The path to the image file in the local filesystem
1048 Specifies the AIO backend (threads/native, default: threads)
1050 Specifies whether the image file is protected with Linux OFD / POSIX locks. The
1051 default is to use the Linux Open File Descriptor API if available, otherwise no
1052 lock is applied. (auto/on/off, default: auto)
1056 -blockdev driver=file,node-name=disk,filename=disk.img
1059 @item Driver-specific options for @code{raw}
1061 This is the image format block driver for raw images. It is usually
1062 stacked on top of a protocol level block driver such as @code{file}.
1066 Reference to or definition of the data source block driver node
1067 (e.g. a @code{file} driver node)
1071 -blockdev driver=file,node-name=disk_file,filename=disk.img
1072 -blockdev driver=raw,node-name=disk,file=disk_file
1076 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
1079 @item Driver-specific options for @code{qcow2}
1081 This is the image format block driver for qcow2 images. It is usually
1082 stacked on top of a protocol level block driver such as @code{file}.
1086 Reference to or definition of the data source block driver node
1087 (e.g. a @code{file} driver node)
1090 Reference to or definition of the backing file block device (default is taken
1091 from the image file). It is allowed to pass @code{null} here in order to disable
1092 the default backing file.
1094 @item lazy-refcounts
1095 Whether to enable the lazy refcounts feature (on/off; default is taken from the
1099 The 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)
1103 The maximum size of the L2 table cache in bytes
1104 (default: if cache-size is not specified - 32M on Linux platforms, and 8M on
1105 non-Linux platforms; otherwise, as large as possible within the cache-size,
1106 while permitting the requested or the minimal refcount cache size)
1108 @item refcount-cache-size
1109 The 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
1111 it which is not used for the L2 cache)
1113 @item cache-clean-interval
1114 Clean unused entries in the L2 and refcount caches. The interval is in seconds.
1115 The default value is 600 on supporting platforms, and 0 on other platforms.
1116 Setting it to 0 disables this feature.
1118 @item pass-discard-request
1119 Whether discard requests to the qcow2 device should be forwarded to the data
1120 source (on/off; default: on if discard=unmap is specified, off otherwise)
1122 @item pass-discard-snapshot
1123 Whether discard requests for the data source should be issued when a snapshot
1124 operation (e.g. deleting a snapshot) frees clusters in the qcow2 file (on/off;
1127 @item pass-discard-other
1128 Whether discard requests for the data source should be issued on other
1129 occasions where a cluster gets freed (on/off; default: off)
1132 Which overlap checks to perform for writes to the image
1133 (none/constant/cached/all; default: cached). For details or finer
1134 granularity control refer to the QAPI documentation of @code{blockdev-add}.
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
1144 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1147 @item Driver-specific options for other drivers
1148 Please refer to the QAPI documentation of the @code{blockdev-add} QMP command.
1154 DEF("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"
1167 " use
'file' as a drive image
\n", QEMU_ARCH_ALL)
1169 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
1172 Define a new drive. This includes creating a block driver node (the backend) as
1173 well as a guest device, and is mostly a shortcut for defining the corresponding
1174 @option{-blockdev} and @option{-device} options.
1176 @option{-drive} accepts all options that are accepted by @option{-blockdev}. In
1177 addition, it knows the following options:
1180 @item file=@var{file}
1181 This option defines which disk image (@pxref{disk_images}) to use with
1182 this drive. If the filename contains comma, you must double it
1183 (for instance, "file
=my
,,file
" to use file "my
,file
").
1185 Special files such as iSCSI devices can be specified using protocol
1186 specific URLs. See the section for "Device URL Syntax
" for more information.
1187 @item if=@var{interface}
1188 This option defines on which type on interface the drive is connected.
1189 Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio, none.
1190 @item bus=@var{bus},unit=@var{unit}
1191 These options define where is connected the drive by defining the bus number and
1193 @item index=@var{index}
1194 This option defines where is connected the drive by using an index in the list
1195 of available connectors of a given interface type.
1196 @item media=@var{media}
1197 This 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
"
1203 and controls how the host cache is used to access block data. This is a
1204 shortcut that sets the @option{cache.direct} and @option{cache.no-flush}
1205 options (as in @option{-blockdev}), and additionally @option{cache.writeback},
1206 which provides a default for the @option{write-cache} option of block guest
1207 devices (as in @option{-device}). The modes correspond to the following
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.
1214 @ │ cache.writeback cache.direct cache.no-flush
1215 ─────────────┼─────────────────────────────────────────────────
1216 writeback │ on off off
1218 writethrough │ off off off
1219 directsync │ off on off
1220 unsafe │ on off on
1223 The default mode is @option{cache=writeback}.
1226 @var{aio} is "threads
", or "native
" and selects between pthread based disk I/O and native Linux AIO.
1227 @item format=@var{format}
1228 Specify which disk @var{format} will be used rather than detecting
1229 the format. Can be used to specify format=raw to avoid interpreting
1230 an untrusted format header.
1231 @item werror=@var{action},rerror=@var{action}
1232 Specify 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
1235 host disk is full; report the error to the guest otherwise).
1236 The 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
1239 file sectors into the image file.
1240 @item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w}
1241 Specify bandwidth throttling limits in bytes per second, either for all request
1242 types or for reads or writes only. Small values can lead to timeouts or hangs
1243 inside 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}
1245 Specify bursts in bytes per second, either for all request types or for reads
1246 or writes only. Bursts allow the guest I/O to spike above the limit
1248 @item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w}
1249 Specify request rate limits in requests per second, either for all request
1250 types or for reads or writes only.
1251 @item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm}
1252 Specify bursts in requests per second, either for all request types or for reads
1253 or writes only. Bursts allow the guest I/O to spike above the limit
1255 @item iops_size=@var{is}
1256 Let every @var{is} bytes of a request count as a new request for iops
1257 throttling purposes. Use this option to prevent guests from circumventing iops
1258 limits by sending fewer but larger requests.
1260 Join a throttling quota group with given name @var{g}. All drives that are
1261 members of the same group are accounted for together. Use this option to
1262 prevent guests from circumventing throttling limits by using many small disks
1263 instead of a single larger disk.
1266 By default, the @option{cache.writeback=on} mode is used. It will report data
1267 writes as completed as soon as the data is present in the host page cache.
1268 This is safe as long as your guest OS makes sure to correctly flush disk caches
1269 where needed. If your guest OS does not handle volatile disk write caches
1270 correctly and your host crashes or loses power, then the guest may experience
1273 For such guests, you should consider using @option{cache.writeback=off}. This
1274 means that the host page cache will be used to read and write data, but write
1275 notification will be sent to the guest only after QEMU has made sure to flush
1276 each write to the disk. Be aware that this has a major impact on performance.
1278 When using the @option{-snapshot} option, unsafe caching is always used.
1280 Copy-on-read avoids accessing the same backing file sectors repeatedly and is
1281 useful when the backing file is over a slow network. By default copy-on-read
1284 Instead of @option{-cdrom} you can use:
1286 @value{qemu_system} -drive file=file,index=2,media=cdrom
1289 Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
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
1298 You can open an image using pre-opened file descriptors from an fd set:
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
1306 You can connect a CDROM to the slave of ide0:
1308 @value{qemu_system_x86} -drive file=file,if=ide,index=1,media=cdrom
1311 If you don't specify the "file
=" argument, you define an empty drive:
1313 @value{qemu_system_x86} -drive if=ide,index=1,media=cdrom
1316 Instead of @option{-fda}, @option{-fdb}, you can use:
1318 @value{qemu_system_x86} -drive file=file,index=0,if=floppy
1319 @value{qemu_system_x86} -drive file=file,index=1,if=floppy
1322 By default, @var{interface} is "ide
" and @var{index} is automatically
1325 @value{qemu_system_x86} -drive file=a -drive file=b"
1327 is interpreted like
:
1329 @value
{qemu_system_x86
} -hda a
-hdb b
1333 DEF("mtdblock", HAS_ARG
, QEMU_OPTION_mtdblock
,
1334 "-mtdblock file use 'file' as on-board Flash memory image\n",
1337 @item
-mtdblock @
var{file
}
1339 Use @
var{file
} as on
-board Flash memory image
.
1342 DEF("sd", HAS_ARG
, QEMU_OPTION_sd
,
1343 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL
)
1345 @item
-sd @
var{file
}
1347 Use @
var{file
} as SecureDigital card image
.
1350 DEF("pflash", HAS_ARG
, QEMU_OPTION_pflash
,
1351 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL
)
1353 @item
-pflash @
var{file
}
1355 Use @
var{file
} as a parallel flash image
.
1358 DEF("snapshot", 0, QEMU_OPTION_snapshot
,
1359 "-snapshot write to temporary files instead of disk image files\n",
1364 Write to temporary files instead of disk image files
. In
this case,
1365 the raw disk image you use is not written back
. You can however force
1366 the write back by pressing @key
{C
-a s
} (@pxref
{disk_images
}).
1369 DEF("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",
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
]
1389 Define a
new file system device
. Valid options are
:
1392 Accesses to the filesystem are done by QEMU
.
1394 Accesses to the filesystem are done by virtfs
-proxy
-helper(1).
1396 Synthetic filesystem
, only used by QTests
.
1398 Specifies identifier
for this device
.
1399 @item path
=@
var{path
}
1400 Specifies the export path
for the file system device
. Files under
1401 this path will be available to the
9p client on the guest
.
1402 @item security_model
=@
var{security_model
}
1403 Specifies the security model to be used
for this export path
.
1404 Supported security models are
"passthrough", "mapped-xattr", "mapped-file" and
"none".
1405 In
"passthrough" security model
, files are stored
using the same
1406 credentials as they are created on the guest
. This requires QEMU
1407 to run as root
. In
"mapped-xattr" security model
, some of the file
1408 attributes like uid
, gid
, mode bits and link target are stored as
1409 file attributes
. For
"mapped-file" these attributes are stored
in the
1410 hidden
.virtfs_metadata directory
. Directories exported by
this security model cannot
1411 interact with other unix tools
. "none" security model is same as
1412 passthrough except the sever won
't report failures if it fails to
1413 set file attributes like ownership. Security model is mandatory
1414 only for local fsdriver. Other fsdrivers (like proxy) don't take
1415 security model as a parameter
.
1416 @item writeout
=@
var{writeout
}
1417 This is an optional argument
. The only supported value is
"immediate".
1418 This means that host page cache will be used to read and write data but
1419 write notification will be sent to the guest only when the data has been
1420 reported as written by the storage subsystem
.
1422 Enables exporting
9p share as a readonly mount
for guests
. By
default
1423 read
-write access is given
.
1424 @item socket
=@
var{socket
}
1425 Enables proxy filesystem driver to use passed socket file
for communicating
1426 with virtfs
-proxy
-helper(1).
1427 @item sock_fd
=@
var{sock_fd
}
1428 Enables proxy filesystem driver to use passed socket descriptor
for
1429 communicating with virtfs
-proxy
-helper(1). Usually a helper like libvirt
1430 will create socketpair and pass one of the fds as sock_fd
.
1431 @item fmode
=@
var{fmode
}
1432 Specifies the
default mode
for newly created files on the host
. Works only
1433 with security models
"mapped-xattr" and
"mapped-file".
1434 @item dmode
=@
var{dmode
}
1435 Specifies the
default mode
for newly created directories on the host
. Works
1436 only 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
}
1438 Specify bandwidth throttling limits
in bytes per second
, either
for all request
1439 types or
for reads or writes only
.
1440 @item throttling
.bps
-total
-max
=@
var{bm
},bps
-read
-max
=@
var{rm
},bps
-write
-max
=@
var{wm
}
1441 Specify bursts
in bytes per second
, either
for all request types or
for reads
1442 or writes only
. Bursts allow the guest I
/O to spike above the limit
1444 @item throttling
.iops
-total
=@
var{i
},throttling
.iops
-read
=@
var{r
}, throttling
.iops
-write
=@
var{w
}
1445 Specify request rate limits
in requests per second
, either
for all request
1446 types 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
}
1448 Specify bursts
in requests per second
, either
for all request types or
for reads
1449 or writes only
. Bursts allow the guest I
/O to spike above the limit temporarily
.
1450 @item throttling
.iops
-size
=@
var{is
}
1451 Let every @
var{is
} bytes of a request count as a
new request
for iops
1452 throttling purposes
.
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
}
1457 Options
for virtio
-9p
-... driver are
:
1460 Specifies the variant to be used
. Supported values are
"pci", "ccw" or
"device",
1461 depending on the machine type
.
1462 @item fsdev
=@
var{id
}
1463 Specifies the id value specified along with
-fsdev option
.
1464 @item mount_tag
=@
var{mount_tag
}
1465 Specifies the tag name to be used by the guest to mount
this export point
.
1470 DEF("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",
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
}
1486 Define 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
:
1489 Accesses to the filesystem are done by QEMU
.
1491 Accesses to the filesystem are done by virtfs
-proxy
-helper(1).
1493 Synthetic filesystem
, only used by QTests
.
1495 Specifies identifier
for the filesystem device
1496 @item path
=@
var{path
}
1497 Specifies the export path
for the file system device
. Files under
1498 this path will be available to the
9p client on the guest
.
1499 @item security_model
=@
var{security_model
}
1500 Specifies the security model to be used
for this export path
.
1501 Supported security models are
"passthrough", "mapped-xattr", "mapped-file" and
"none".
1502 In
"passthrough" security model
, files are stored
using the same
1503 credentials as they are created on the guest
. This requires QEMU
1504 to run as root
. In
"mapped-xattr" security model
, some of the file
1505 attributes like uid
, gid
, mode bits and link target are stored as
1506 file attributes
. For
"mapped-file" these attributes are stored
in the
1507 hidden
.virtfs_metadata directory
. Directories exported by
this security model cannot
1508 interact with other unix tools
. "none" security model is same as
1509 passthrough except the sever won
't report failures if it fails to
1510 set file attributes like ownership. Security model is mandatory only
1511 for local fsdriver. Other fsdrivers (like proxy) don't take security
1512 model as a parameter
.
1513 @item writeout
=@
var{writeout
}
1514 This is an optional argument
. The only supported value is
"immediate".
1515 This means that host page cache will be used to read and write data but
1516 write notification will be sent to the guest only when the data has been
1517 reported as written by the storage subsystem
.
1519 Enables exporting
9p share as a readonly mount
for guests
. By
default
1520 read
-write access is given
.
1521 @item socket
=@
var{socket
}
1522 Enables proxy filesystem driver to use passed socket file
for
1523 communicating with virtfs
-proxy
-helper(1). Usually a helper like libvirt
1524 will create socketpair and pass one of the fds as sock_fd
.
1526 Enables proxy filesystem driver to use passed
'sock_fd' as the socket
1527 descriptor
for interfacing with virtfs
-proxy
-helper(1).
1528 @item fmode
=@
var{fmode
}
1529 Specifies the
default mode
for newly created files on the host
. Works only
1530 with security models
"mapped-xattr" and
"mapped-file".
1531 @item dmode
=@
var{dmode
}
1532 Specifies the
default mode
for newly created directories on the host
. Works
1533 only with security models
"mapped-xattr" and
"mapped-file".
1534 @item mount_tag
=@
var{mount_tag
}
1535 Specifies the tag name to be used by the guest to mount
this export point
.
1536 @item multidevs
=@
var{multidevs
}
1537 Specifies how to deal with multiple devices being shared with a
9p export
.
1538 Supported behaviours are either
"remap", "forbid" or
"warn". The latter is
1539 the
default behaviour on which virtfs
9p expects only one device to be
1540 shared with the same export
, and
if more than one device is shared and
1541 accessed 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
1543 you should either create a separate virtfs export
for each device to be
1544 shared with
guests (recommended way
) or you might use
"remap" instead which
1545 allows you to share multiple devices with only one export instead
, which is
1546 achieved by remapping the original inode numbers from host to guest
in a
1547 way that would prevent such collisions
. Remapping inodes
in such use cases
1548 is required because the original device IDs from host are
never passed and
1549 exposed on guest
. Instead all files of an export shared with virtfs always
1550 share the same device id on guest
. So two files with identical inode
1551 numbers but from actually different devices on host would otherwise cause a
1552 file ID collision and hence potential misbehaviours on guest
. "forbid" on
1553 the other hand assumes like
"warn" that only one device is shared by the
1554 same export
, however it will not only log a warning message but also
1555 deny access to additional devices on guest
. Note though that
"forbid" does
1556 currently not block all possible file access
operations (e
.g
. readdir()
1557 would still
return entries from other devices
).
1561 DEF("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
)
1571 Configure iSCSI session parameters
.
1579 DEFHEADING(USB options
:)
1584 DEF("usb", 0, QEMU_OPTION_usb
,
1585 "-usb enable on-board USB host controller (if not enabled by default)\n",
1590 Enable USB emulation on machine types with an on
-board USB host
controller (if
1591 not enabled by
default). Note that on
-board USB host controllers may not
1592 support USB
3.0. In
this case @option
{-device qemu
-xhci
} can be used instead
1593 on machines with PCI
.
1596 DEF("usbdevice", HAS_ARG
, QEMU_OPTION_usbdevice
,
1597 "-usbdevice name add the host or guest USB device 'name'\n",
1601 @item
-usbdevice @
var{devname
}
1603 Add the USB device @
var{devname
}. Note that
this option is deprecated
,
1604 please use @code
{-device usb
-...} instead
. @xref
{usb_devices
}.
1609 Virtual Mouse
. This will
override the PS
/2 mouse emulation when activated
.
1612 Pointer device that uses absolute
coordinates (like a touchscreen
). This
1613 means QEMU is able to report the mouse position without having to grab the
1614 mouse
. Also overrides the PS
/2 mouse emulation when activated
.
1617 Braille device
. This will use BrlAPI to display the braille output on a real
1628 DEFHEADING(Display options
:)
1633 DEF("display", HAS_ARG
, QEMU_OPTION_display
,
1634 #
if defined(CONFIG_SPICE
)
1635 "-display spice-app[,gl=on|off]\n"
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"
1641 #
if defined(CONFIG_GTK
)
1642 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1644 #
if defined(CONFIG_VNC
)
1645 "-display vnc=<display>[,<optargs>]\n"
1647 #
if defined(CONFIG_CURSES
)
1648 "-display curses[,charset=<encoding>]\n"
1650 #
if defined(CONFIG_OPENGL
)
1651 "-display egl-headless[,rendernode=<file>]\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"
1665 "\"-display none\"\n"
1669 @item
-display @
var{type
}
1671 Select type of display to use
. This option is a replacement
for the
1672 old style
-sdl
/-curses
/... options
. Use @code
{-display help
} to list
1673 the available display types
. Valid values
for @
var{type
} are
1676 Display video output via
SDL (usually
in a separate graphics
1677 window
; see the SDL documentation
for other possibilities
).
1679 Display video output via curses
. For graphics device models which
1680 support a text mode
, QEMU can display
this output
using a
1681 curses
/ncurses
interface. Nothing is displayed when the graphics
1682 device is
in graphical mode or
if the graphics device does not support
1683 a text mode
. Generally only the VGA device models support text mode
.
1684 The font charset used by the guest can be specified with the
1685 @code
{charset
} option
, for example @code
{charset
=CP850
} for IBM CP850
1686 encoding
. The
default is @code
{CP437
}.
1688 Do not display video output
. The guest will still see an emulated
1689 graphics card
, but its output will not be displayed to the QEMU
1690 user
. This option differs from the
-nographic option
in that it
1691 only affects what is done with video output
; -nographic also changes
1692 the destination of the serial and parallel port data
.
1694 Display video output
in a GTK window
. This
interface provides drop
-down
1695 menus and other UI elements to configure and control the VM during
1698 Start a VNC server on display
<arg
>
1700 Offload all OpenGL operations to a local DRI device
. For any graphical display
,
1701 this display needs to be paired with either VNC or SPICE displays
.
1703 Start QEMU as a Spice server and launch the
default Spice client
1704 application
. The Spice server will redirect the serial consoles and
1705 QEMU monitors
. (Since
4.0)
1709 DEF("nographic", 0, QEMU_OPTION_nographic
,
1710 "-nographic disable graphical output and redirect serial I/Os to console\n",
1715 Normally
, if QEMU is compiled with graphical window support
, it displays
1716 output such as guest graphics
, guest console
, and the QEMU monitor
in a
1717 window
. With
this option
, you can totally disable graphical output so
1718 that QEMU is a simple command line application
. The emulated serial port
1719 is redirected on the console and muxed with the
monitor (unless
1720 redirected elsewhere explicitly
). Therefore
, you can still use QEMU to
1721 debug a Linux kernel with a serial console
. Use @key
{C
-a h
} for help on
1722 switching between the console and monitor
.
1725 DEF("curses", 0, QEMU_OPTION_curses
,
1726 "-curses shorthand for -display curses\n",
1731 Normally
, if QEMU is compiled with graphical window support
, it displays
1732 output such as guest graphics
, guest console
, and the QEMU monitor
in a
1733 window
. With
this option
, QEMU can display the VGA output when
in text
1734 mode
using a curses
/ncurses
interface. Nothing is displayed
in graphical
1738 DEF("alt-grab", 0, QEMU_OPTION_alt_grab
,
1739 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1744 Use Ctrl
-Alt
-Shift to grab
mouse (instead of Ctrl
-Alt
). Note that
this also
1745 affects the special
keys (for fullscreen
, monitor
-mode switching
, etc
).
1748 DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab
,
1749 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1754 Use Right
-Ctrl to grab
mouse (instead of Ctrl
-Alt
). Note that
this also
1755 affects the special
keys (for fullscreen
, monitor
-mode switching
, etc
).
1758 DEF("no-quit", 0, QEMU_OPTION_no_quit
,
1759 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL
)
1763 Disable SDL window close capability
.
1766 DEF("sdl", 0, QEMU_OPTION_sdl
,
1767 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL
)
1774 DEF("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"
1791 " at least one of {port, tls-port} is mandatory\n",
1794 @item
-spice @
var{option
}[,@
var{option
}[,...]]
1796 Enable the spice remote desktop protocol
. Valid options are
1801 Set the TCP port spice is listening on
for plaintext channels
.
1804 Set the IP address spice is listening on
. Default is any address
.
1809 Force
using the specified IP version
.
1811 @item password
=<secret
>
1812 Set the password you need to authenticate
.
1815 Require that the client use SASL to authenticate with the spice
.
1816 The exact choice of authentication method used is controlled from the
1817 system
/ user
's SASL configuration file for the 'qemu
' service. This
1818 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1819 unprivileged user, an environment variable SASL_CONF_PATH can be used
1820 to make it search alternate locations for the service config.
1821 While some SASL auth methods can also provide data encryption (eg GSSAPI),
1822 it is recommended that SASL always be combined with the 'tls
' and
1823 'x509
' settings to enable use of SSL and server certificates. This
1824 ensures a data encryption preventing compromise of authentication
1827 @item disable-ticketing
1828 Allow client connects without authentication.
1830 @item disable-copy-paste
1831 Disable copy paste between the client and the guest.
1833 @item disable-agent-file-xfer
1834 Disable spice-vdagent based file-xfer between the client and the guest.
1837 Set the TCP port spice is listening on for encrypted channels.
1839 @item x509-dir=<dir>
1840 Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
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>
1847 The x509 file names can also be configured individually.
1849 @item tls-ciphers=<list>
1850 Specify which ciphers to use.
1852 @item tls-channel=[main|display|cursor|inputs|record|playback]
1853 @itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1854 Force specific channel to be used with or without TLS encryption. The
1855 options can be specified multiple times to configure multiple
1856 channels. The special name "default" can be used to set the default
1857 mode. For channels which are not explicitly forced into one mode the
1858 spice client is allowed to pick tls/plaintext as he pleases.
1860 @item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1861 Configure image compression (lossless).
1862 Default is auto_glz.
1864 @item jpeg-wan-compression=[auto|never|always]
1865 @itemx zlib-glz-wan-compression=[auto|never|always]
1866 Configure wan image compression (lossy for slow links).
1869 @item streaming-video=[off|all|filter]
1870 Configure video stream detection. Default is off.
1872 @item agent-mouse=[on|off]
1873 Enable/disable passing mouse events via vdagent. Default is on.
1875 @item playback-compression=[on|off]
1876 Enable/disable audio stream compression (using celt 0.5.1). Default is on.
1878 @item seamless-migration=[on|off]
1879 Enable/disable spice seamless migration. Default is off.
1882 Enable/disable OpenGL context. Default is off.
1884 @item rendernode=<file>
1885 DRM render node for OpenGL rendering. If not specified, it will pick
1886 the first available. (Since 2.9)
1891 DEF("portrait", 0, QEMU_OPTION_portrait,
1892 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
1897 Rotate graphical output 90 deg left (only PXA LCD).
1900 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
1901 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
1904 @item -rotate @var{deg}
1906 Rotate graphical output some deg left (only PXA LCD).
1909 DEF("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)
1913 @item -vga @var{type}
1915 Select type of VGA card to emulate. Valid values for @var{type} are
1918 Cirrus Logic GD5446 Video card. All Windows versions starting from
1919 Windows 95 should recognize and use this graphic card. For optimal
1920 performances, use 16 bit color depth in the guest and the host OS.
1921 (This card was the default before QEMU 2.2)
1923 Standard VGA card with Bochs VBE extensions. If your guest OS
1924 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1925 to use high resolution modes (>= 1280x1024x16) then you should use
1926 this option. (This card is the default since QEMU 2.2)
1928 VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1929 recent XFree86/XOrg server or Windows guest with a driver for this
1932 QXL paravirtual graphic card. It is VGA compatible (including VESA
1933 2.0 VBE support). Works best with qxl guest drivers installed though.
1934 Recommended choice when using the spice protocol.
1936 (sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1937 sun4m machines and offers both 8-bit and 24-bit colour depths at a
1938 fixed resolution of 1024x768.
1940 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1941 for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1942 resolutions aimed at people wishing to run older Solaris versions.
1950 DEF("full-screen", 0, QEMU_OPTION_full_screen,
1951 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
1954 @findex -full-screen
1955 Start in full screen.
1958 DEF("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)
1962 @item -g @var{width}x@var{height}[x@var{depth}]
1964 Set the initial graphical resolution and depth (PPC, SPARC only).
1967 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
1968 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
1970 @item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1972 Normally, if QEMU is compiled with graphical window support, it displays
1973 output such as guest graphics, guest console, and the QEMU monitor in a
1974 window. 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
1976 very useful to enable the usb tablet device when using this option
1977 (option @option{-device usb-tablet}). When using the VNC display, you
1978 must use the @option{-k} parameter to set the keyboard layout if you are
1979 not using en-us. Valid syntax for the @var{display} is
1985 With this option, QEMU will try next available VNC @var{display}s, until the
1986 number @var{L}, if the origianlly defined "-vnc @var{display}" is not
1987 available, e.g. port 5900+@var{display} is already used by another
1988 application. By default, to=0.
1990 @item @var{host}:@var{d}
1992 TCP connections will only be allowed from @var{host} on display @var{d}.
1993 By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1994 be omitted in which case the server will accept connections from any host.
1996 @item unix:@var{path}
1998 Connections will be allowed over UNIX domain sockets where @var{path} is the
1999 location of a unix socket to listen for connections on.
2003 VNC is initialized but not started. The monitor @code{change} command
2004 can be used to later start the VNC server.
2008 Following the @var{display} value there may be one or more @var{option} flags
2009 separated by commas. Valid options are
2015 Connect to a listening VNC client via a ``reverse'' connection. The
2016 client is specified by the @var{display}. For reverse network
2017 connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
2018 is a TCP port number, not a display number.
2022 Opens an additional TCP listening port dedicated to VNC Websocket connections.
2023 If a bare @var{websocket} option is given, the Websocket port is
2024 5700+@var{display}. An alternative port can be specified with the
2025 syntax @code{websocket}=@var{port}.
2027 If @var{host} is specified connections will only be allowed from this host.
2028 It is possible to control the websocket listen address independently, using
2029 the syntax @code{websocket}=@var{host}:@var{port}.
2031 If no TLS credentials are provided, the websocket connection runs in
2032 unencrypted mode. If TLS credentials are provided, the websocket connection
2033 requires encrypted client connections.
2037 Require that password based authentication is used for client connections.
2039 The password must be set separately using the @code{set_password} command in
2040 the @ref{pcsys_monitor}. The syntax to change your password is:
2041 @code{set_password <protocol> <password>} where <protocol> could be either
2044 If you would like to change <protocol> password expiration, you should use
2045 @code{expire_password <protocol> <expiration-time>} where expiration time could
2046 be one of the following options: now, never, +seconds or UNIX time of
2047 expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
2048 to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this
2051 You can also use keywords "now" or "never" for the expiration time to
2052 allow <protocol> password to expire immediately or never expire.
2054 @item tls-creds=@var{ID}
2056 Provides the ID of a set of TLS credentials to use to secure the
2057 VNC server. They will apply to both the normal VNC server socket
2058 and the websocket socket (if enabled). Setting TLS credentials
2059 will cause the VNC server socket to enable the VeNCrypt auth
2060 mechanism. The credentials should have been previously created
2061 using the @option{-object tls-creds} argument.
2063 @item tls-authz=@var{ID}
2065 Provides the ID of the QAuthZ authorization object against which
2066 the client's x509 distinguished name will validated
. This object is
2067 only resolved at time of use
, so can be deleted and recreated on the
2068 fly
while the VNC server is active
. If missing
, it will
default
2073 Require that the client use SASL to authenticate with the VNC server
.
2074 The exact choice of authentication method used is controlled from the
2075 system
/ user
's SASL configuration file for the 'qemu
' service. This
2076 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
2077 unprivileged user, an environment variable SASL_CONF_PATH can be used
2078 to make it search alternate locations for the service config.
2079 While some SASL auth methods can also provide data encryption (eg GSSAPI),
2080 it is recommended that SASL always be combined with the 'tls
' and
2081 'x509
' settings to enable use of SSL and server certificates. This
2082 ensures a data encryption preventing compromise of authentication
2083 credentials. See the @ref{vnc_security} section for details on using
2084 SASL authentication.
2086 @item sasl-authz=@var{ID}
2088 Provides the ID of the QAuthZ authorization object against which
2089 the client's SASL username will validated
. This object is
2090 only resolved at time of use
, so can be deleted and recreated on the
2091 fly
while the VNC server is active
. If missing
, it will
default
2096 Legacy method
for enabling authorization of clients against the
2097 x509 distinguished name and SASL username
. It results
in the creation
2098 of two @code
{authz
-list
} objects with IDs of @code
{vnc
.username
} and
2099 @code
{vnc
.x509dname
}. The rules
for these objects must be configured
2100 with the HMP ACL commands
.
2102 This option is deprecated and should no longer be used
. The
new
2103 @option
{sasl
-authz
} and @option
{tls
-authz
} options are a
2108 Enable lossy compression
methods (gradient
, JPEG
, ...). If
this
2109 option is set
, VNC client may receive lossy framebuffer updates
2110 depending on its encoding settings
. Enabling
this option can save
2111 a lot of bandwidth at the expense of quality
.
2115 Disable adaptive encodings
. Adaptive encodings are enabled by
default.
2116 An adaptive encoding will
try to detect frequently updated screen regions
,
2117 and send updates
in these regions
using a lossy
encoding (like JPEG
).
2118 This can be really helpful to save bandwidth when playing videos
. Disabling
2119 adaptive encodings restores the original
static behavior of encodings
2122 @item share
=[allow
-exclusive|force
-shared|ignore
]
2124 Set display sharing policy
. 'allow-exclusive' allows clients to ask
2125 for exclusive access
. As suggested by the rfb spec
this is
2126 implemented by dropping other connections
. Connecting multiple
2127 clients
in parallel requires all clients asking
for a shared session
2128 (vncviewer
: -shared
switch). This is the
default. 'force-shared'
2129 disables exclusive client access
. Useful
for shared desktop sessions
,
2130 where you don
't want someone forgetting specify -shared disconnect
2131 everybody else. 'ignore
' completely ignores the shared flag and
2132 allows everybody connect unconditionally. Doesn't conform to the rfb
2133 spec but is traditional QEMU behavior
.
2137 Set keyboard delay
, for key down and key up events
, in milliseconds
.
2138 Default is
10. Keyboards are low
-bandwidth devices
, so
this slowdown
2139 can help the device and guest to keep up and not lose events
in case
2140 events are arriving
in bulk
. Possible causes
for the latter are flaky
2141 network connections
, or scripts
for automated testing
.
2143 @item audiodev
=@
var{audiodev
}
2145 Use the specified @
var{audiodev
} when the VNC client requests audio
2146 transmission
. When not
using an
-audiodev argument
, this option must
2147 be omitted
, otherwise is must be present and specify a valid audiodev
.
2155 ARCHHEADING(, QEMU_ARCH_I386
)
2157 ARCHHEADING(i386 target only
:, QEMU_ARCH_I386
)
2162 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack
,
2163 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2168 Use it when installing Windows
2000 to avoid a disk full bug
. After
2169 Windows
2000 is installed
, you no longer need
this option (this option
2170 slows down the IDE transfers
).
2173 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk
,
2174 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2177 @item
-no
-fd
-bootchk
2178 @findex
-no
-fd
-bootchk
2179 Disable boot signature checking
for floppy disks
in BIOS
. May
2180 be needed to boot from old floppy disks
.
2183 DEF("no-acpi", 0, QEMU_OPTION_no_acpi
,
2184 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM
)
2188 Disable
ACPI (Advanced Configuration and Power Interface
) support
. Use
2189 it
if your guest OS complains about ACPI
problems (PC target machine
2193 DEF("no-hpet", 0, QEMU_OPTION_no_hpet
,
2194 "-no-hpet disable HPET\n", QEMU_ARCH_I386
)
2198 Disable HPET support
.
2201 DEF("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
)
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
}]...]
2207 Add ACPI table with specified header fields and context from specified files
.
2208 For file
=, take whole ACPI table from the specified files
, including all
2209 ACPI
headers (possible overridden by other options
).
2210 For data
=, only data
2211 portion of the table is used
, all header information is specified
in the
2213 If a SLIC table is supplied to QEMU
, then the SLIC
's oem_id and oem_table_id
2214 fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
2215 to ensure the field matches required by the Microsoft SLIC spec and the ACPI
2219 DEF("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"
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"
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)
2242 @item -smbios file=@var{binary}
2244 Load SMBIOS entry from binary file.
2246 @item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
2247 Specify SMBIOS type 0 fields
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}]
2250 Specify SMBIOS type 1 fields
2252 @item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}]
2253 Specify SMBIOS type 2 fields
2255 @item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
2256 Specify SMBIOS type 3 fields
2258 @item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
2259 Specify SMBIOS type 4 fields
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}]
2262 Specify SMBIOS type 17 fields
2270 DEFHEADING(Network options:)
2275 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
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]"
2283 "[,smb=dir[,smbserver=addr]]\n"
2285 " configure a user mode network backend with ID 'str
',\n"
2286 " its DHCP server and optional services\n"
2289 "-netdev tap,id=str,ifname=name\n"
2290 " configure a host TAP network backend with ID 'str
'\n"
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"
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"
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"
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"
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"
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"
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"
2373 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2374 " configure a vhost-user network, backed by a chardev 'dev
'\n"
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)
2378 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2389 #ifdef CONFIG_NETMAP
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",
2401 DEF("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"
2414 #ifdef CONFIG_NETMAP
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)
2421 @item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]
2423 This option is a shortcut for configuring both the on-board (default) guest
2424 NIC hardware and the host network backend in one go. The host backend options
2425 are the same as with the corresponding @option{-netdev} options below.
2426 The guest NIC model can be set with @option{model=@var{modelname}}.
2427 Use @option{model=help} to list the available device types.
2428 The hardware MAC address can be set with @option{mac=@var{macaddr}}.
2430 The following two example do exactly the same, to show how @option{-nic} can
2431 be used to shorten the command line length (note that the e1000 is the default
2432 on i386, so the @option{model=e1000} parameter could even be omitted here, too):
2434 @value{qemu_system} -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2435 @value{qemu_system} -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2439 Indicate that no network devices should be configured. It is used to override
2440 the default configuration (default NIC with ``user'' host network backend)
2441 which is activated if no other networking options are provided.
2443 @item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
2445 Configure user mode host network backend which requires no administrator
2446 privilege to run. Valid options are:
2450 Assign symbolic name for use in monitor commands.
2452 @item ipv4=on|off and ipv6=on|off
2453 Specify that either IPv4 or IPv6 must be enabled. If neither is specified
2454 both protocols are enabled.
2456 @item net=@var{addr}[/@var{mask}]
2457 Set IP network address the guest will see. Optionally specify the netmask,
2458 either in the form a.b.c.d or as number of valid top-most bits. Default is
2461 @item host=@var{addr}
2462 Specify the guest-visible address of the host. Default is the 2nd IP in the
2463 guest network, i.e. x.x.x.2.
2465 @item ipv6-net=@var{addr}[/@var{int}]
2466 Set IPv6 network address the guest will see (default is fec0::/64). The
2467 network prefix is given in the usual hexadecimal IPv6 address
2468 notation. The prefix size is optional, and is given as the number of
2469 valid top-most bits (default is 64).
2471 @item ipv6-host=@var{addr}
2472 Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
2473 the guest network, i.e. xxxx::2.
2475 @item restrict=on|off
2476 If this option is enabled, the guest will be isolated, i.e. it will not be
2477 able to contact the host and no guest IP packets will be routed over the host
2478 to the outside. This option does not affect any explicitly set forwarding rules.
2480 @item hostname=@var{name}
2481 Specifies the client hostname reported by the built-in DHCP server.
2483 @item dhcpstart=@var{addr}
2484 Specify the first of the 16 IPs the built-in DHCP server can assign. Default
2485 is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
2487 @item dns=@var{addr}
2488 Specify the guest-visible address of the virtual nameserver. The address must
2489 be different from the host address. Default is the 3rd IP in the guest network,
2492 @item ipv6-dns=@var{addr}
2493 Specify the guest-visible address of the IPv6 virtual nameserver. The address
2494 must be different from the host address. Default is the 3rd IP in the guest
2495 network, i.e. xxxx::3.
2497 @item dnssearch=@var{domain}
2498 Provides an entry for the domain-search list sent by the built-in
2499 DHCP server. More than one domain suffix can be transmitted by specifying
2500 this option multiple times. If supported, this will cause the guest to
2501 automatically try to append the given domain suffix(es) in case a domain name
2502 can not be resolved.
2506 @value{qemu_system} -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2509 @item domainname=@var{domain}
2510 Specifies the client domain name reported by the built-in DHCP server.
2512 @item tftp=@var{dir}
2513 When using the user mode network stack, activate a built-in TFTP
2514 server. The files in @var{dir} will be exposed as the root of a TFTP server.
2515 The TFTP client on the guest must be configured in binary mode (use the command
2516 @code{bin} of the Unix TFTP client).
2518 @item tftp-server-name=@var{name}
2519 In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option
2520 66). This can be used to advise the guest to load boot files or configurations
2521 from a different server than the host address.
2523 @item bootfile=@var{file}
2524 When using the user mode network stack, broadcast @var{file} as the BOOTP
2525 filename. In conjunction with @option{tftp}, this can be used to network boot
2526 a guest from a local directory.
2528 Example (using pxelinux):
2530 @value{qemu_system} -hda linux.img -boot n -device e1000,netdev=n1 \
2531 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2534 @item smb=@var{dir}[,smbserver=@var{addr}]
2535 When using the user mode network stack, activate a built-in SMB
2536 server so that Windows OSes can access to the host files in @file{@var{dir}}
2537 transparently. The IP address of the SMB server can be set to @var{addr}. By
2538 default the 4th IP in the guest network is used, i.e. x.x.x.4.
2540 In the guest Windows OS, the line:
2544 must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
2545 or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
2547 Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
2549 Note that a SAMBA server must be installed on the host OS.
2551 @item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
2552 Redirect incoming TCP or UDP connections to the host port @var{hostport} to
2553 the guest IP address @var{guestaddr} on guest port @var{guestport}. If
2554 @var{guestaddr} is not specified, its value is x.x.x.15 (default first address
2555 given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
2556 be bound to a specific host interface. If no connection type is set, TCP is
2557 used. This option can be given multiple times.
2559 For example, to redirect host X11 connection from screen 1 to guest
2560 screen 0, use the following:
2564 @value{qemu_system} -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2565 # this host xterm should open in the guest X11 server
2569 To redirect telnet connections from host port 5555 to telnet port on
2570 the guest, use the following:
2574 @value{qemu_system} -nic user,hostfwd=tcp::5555-:23
2575 telnet localhost 5555
2578 Then when you use on the host @code{telnet localhost 5555}, you
2579 connect to the guest telnet server.
2581 @item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
2582 @itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
2583 Forward guest TCP connections to the IP address @var{server} on port @var{port}
2584 to the character device @var{dev} or to a program executed by @var{cmd:command}
2585 which gets spawned for each connection. This option can be given multiple times.
2587 You can either use a chardev directly and have that one used throughout QEMU's
2588 lifetime
, like
in the following example
:
2591 # open
10.10.1.1:4321 on bootup
, connect
10.0.2.100:1234 to it whenever
2592 # the guest accesses it
2593 @value
{qemu_system
} -nic user
,guestfwd
=tcp
:10.0.2.100:1234-tcp
:10.10.1.1:4321
2596 Or you can execute a command on every TCP connection established by the guest
,
2597 so that QEMU behaves similar to an inetd process
for that virtual server
:
2600 # call
"netcat 10.10.1.1 4321" on every TCP connection to
10.0.2.100:1234
2601 # and connect the TCP stream to its stdin
/stdout
2602 @value
{qemu_system
} -nic
'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2607 @item
-netdev tap
,id
=@
var{id
}[,fd
=@
var{h
}][,ifname
=@
var{name
}][,script
=@
var{file
}][,downscript
=@
var{dfile
}][,br
=@
var{bridge
}][,helper
=@
var{helper
}]
2608 Configure a host TAP network backend with ID @
var{id
}.
2610 Use the network script @
var{file
} to configure it and the network script
2611 @
var{dfile
} to deconfigure it
. If @
var{name
} is not provided
, the OS
2612 automatically provides one
. The
default network configure script is
2613 @file
{/etc
/qemu
-ifup
} and the
default network deconfigure script is
2614 @file
{/etc
/qemu
-ifdown
}. Use @option
{script
=no
} or @option
{downscript
=no
}
2615 to disable script execution
.
2617 If running QEMU as an unprivileged user
, use the network helper
2618 @
var{helper
} to configure the TAP
interface and attach it to the bridge
.
2619 The
default network helper executable is @file
{/path
/to
/qemu
-bridge
-helper
}
2620 and the
default bridge device is @file
{br0
}.
2622 @option
{fd
}=@
var{h
} can be used to specify the handle of an already
2623 opened host TAP
interface.
2628 #launch a QEMU instance with the
default network script
2629 @value
{qemu_system
} linux
.img
-nic tap
2633 #launch a QEMU instance with two NICs
, each one connected
2635 @value
{qemu_system
} linux
.img \
2636 -netdev tap
,id
=nd0
,ifname
=tap0
-device e1000
,netdev
=nd0 \
2637 -netdev tap
,id
=nd1
,ifname
=tap1
-device rtl8139
,netdev
=nd1
2641 #launch a QEMU instance with the
default network helper to
2642 #connect a TAP device to bridge br0
2643 @value
{qemu_system
} linux
.img
-device virtio
-net
-pci
,netdev
=n1 \
2644 -netdev tap
,id
=n1
,"helper=/path/to/qemu-bridge-helper"
2647 @item
-netdev bridge
,id
=@
var{id
}[,br
=@
var{bridge
}][,helper
=@
var{helper
}]
2648 Connect a host TAP network
interface to a host bridge device
.
2650 Use the network helper @
var{helper
} to configure the TAP
interface and
2651 attach it to the bridge
. The
default network helper executable is
2652 @file
{/path
/to
/qemu
-bridge
-helper
} and the
default bridge
2653 device is @file
{br0
}.
2658 #launch a QEMU instance with the
default network helper to
2659 #connect a TAP device to bridge br0
2660 @value
{qemu_system
} linux
.img
-netdev bridge
,id
=n1
-device virtio
-net
,netdev
=n1
2664 #launch a QEMU instance with the
default network helper to
2665 #connect a TAP device to bridge qemubr0
2666 @value
{qemu_system
} linux
.img
-netdev bridge
,br
=qemubr0
,id
=n1
-device virtio
-net
,netdev
=n1
2669 @item
-netdev socket
,id
=@
var{id
}[,fd
=@
var{h
}][,listen
=[@
var{host
}]:@
var{port
}][,connect
=@
var{host
}:@
var{port
}]
2671 This host network backend can be used to connect the guest
's network to
2672 another QEMU virtual machine using a TCP socket connection. If @option{listen}
2673 is specified, QEMU waits for incoming connections on @var{port}
2674 (@var{host} is optional). @option{connect} is used to connect to
2675 another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2676 specifies an already opened TCP socket.
2680 # launch a first QEMU instance
2681 @value{qemu_system} linux.img \
2682 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2683 -netdev socket,id=n1,listen=:1234
2684 # connect the network of this instance to the network of the first instance
2685 @value{qemu_system} linux.img \
2686 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2687 -netdev socket,id=n2,connect=127.0.0.1:1234
2690 @item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2692 Configure a socket host network backend to share the guest's network traffic
2693 with another QEMU virtual machines
using a UDP multicast socket
, effectively
2694 making a bus
for every QEMU with same multicast address @
var{maddr
} and @
var{port
}.
2698 Several QEMU can be running on different hosts and share same
bus (assuming
2699 correct multicast setup
for these hosts
).
2701 mcast support is compatible with User Mode
Linux (argument @option
{eth@
var{N
}=mcast
}), see
2702 @url
{http
://user-mode-linux.sf.net}.
2704 Use @option
{fd
=h
} to specify an already opened UDP multicast socket
.
2709 # launch one QEMU instance
2710 @value
{qemu_system
} linux
.img \
2711 -device e1000
,netdev
=n1
,mac
=52:54:00:12:34:56 \
2712 -netdev socket
,id
=n1
,mcast
=230.0.0.1:1234
2713 # launch another QEMU instance on same
"bus"
2714 @value
{qemu_system
} linux
.img \
2715 -device e1000
,netdev
=n2
,mac
=52:54:00:12:34:57 \
2716 -netdev socket
,id
=n2
,mcast
=230.0.0.1:1234
2717 # launch yet another QEMU instance on same
"bus"
2718 @value
{qemu_system
} linux
.img \
2719 -device e1000
,netdev
=n3
,mac
=52:54:00:12:34:58 \
2720 -netdev socket
,id
=n3
,mcast
=230.0.0.1:1234
2723 Example (User Mode Linux compat
.):
2725 # launch QEMU
instance (note mcast address selected is UML
's default)
2726 @value{qemu_system} linux.img \
2727 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2728 -netdev socket,id=n1,mcast=239.192.168.1:1102
2730 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
2733 Example (send packets from host's
1.2.3.4):
2735 @value
{qemu_system
} linux
.img \
2736 -device e1000
,netdev
=n1
,mac
=52:54:00:12:34:56 \
2737 -netdev socket
,id
=n1
,mcast
=239.192.168.1:1102,localaddr
=1.2.3.4
2740 @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
}]
2741 Configure a L2TPv3 pseudowire host network backend
. L2TPv3 (RFC3391
) is a
2742 popular protocol to transport
Ethernet (and other Layer
2) data frames between
2743 two systems
. It is present
in routers
, firewalls and the Linux kernel
2744 (from version
3.3 onwards
).
2746 This transport allows a VM to communicate to another VM
, router or firewall directly
.
2749 @item src
=@
var{srcaddr
}
2750 source
address (mandatory
)
2751 @item dst
=@
var{dstaddr
}
2752 destination
address (mandatory
)
2754 select udp
encapsulation (default is ip
).
2755 @item srcport
=@
var{srcport
}
2757 @item dstport
=@
var{dstport
}
2758 destination udp port
.
2760 force v6
, otherwise defaults to v4
.
2761 @item rxcookie
=@
var{rxcookie
}
2762 @itemx txcookie
=@
var{txcookie
}
2763 Cookies are a weak form of security
in the l2tpv3 specification
.
2764 Their
function is mostly to prevent misconfiguration
. By
default they are
32
2767 Set cookie size to
64 bit instead of the
default 32
2769 Force a
'cut-down' L2TPv3 with no counter as
in
2770 draft
-mkonstan
-l2tpext
-keyed
-ipv6
-tunnel
-00
2772 Work around broken counter handling
in peer
. This may also help on
2773 networks which have packet reorder
.
2774 @item offset
=@
var{offset
}
2775 Add an extra offset between header and data
2778 For example
, to attach a VM running on host
4.3.2.1 via L2TPv3 to the bridge br
-lan
2779 on the remote Linux host
1.2.3.4:
2781 # Setup tunnel on linux host
using raw ip as encapsulation
2783 ip l2tp add tunnel remote
4.3.2.1 local
1.2.3.4 tunnel_id
1 peer_tunnel_id
1 \
2784 encap udp udp_sport
16384 udp_dport
16384
2785 ip l2tp add session tunnel_id
1 name vmtunnel0 session_id \
2786 0xFFFFFFFF peer_session_id
0xFFFFFFFF
2787 ifconfig vmtunnel0 mtu
1500
2788 ifconfig vmtunnel0 up
2789 brctl addif br
-lan vmtunnel0
2793 # launch QEMU instance
- if your network has reorder or is very lossy add
,pincounter
2795 @value
{qemu_system
} linux
.img
-device e1000
,netdev
=n1 \
2796 -netdev l2tpv3
,id
=n1
,src
=4.2.3.1,dst
=1.2.3.4,udp
,srcport
=16384,dstport
=16384,rxsession
=0xffffffff,txsession
=0xffffffff,counter
2800 @item
-netdev vde
,id
=@
var{id
}[,sock
=@
var{socketpath
}][,port
=@
var{n
}][,group
=@
var{groupname
}][,mode
=@
var{octalmode
}]
2801 Configure VDE backend to connect to PORT @
var{n
} of a vde
switch running on host and
2802 listening
for incoming connections on @
var{socketpath
}. Use GROUP @
var{groupname
}
2803 and MODE @
var{octalmode
} to change
default ownership and permissions
for
2804 communication port
. This option is only available
if QEMU has been compiled
2805 with vde support enabled
.
2810 vde_switch
-F
-sock
/tmp
/myswitch
2811 # launch QEMU instance
2812 @value
{qemu_system
} linux
.img
-nic vde
,sock
=/tmp
/myswitch
2815 @item
-netdev vhost
-user
,chardev
=@
var{id
}[,vhostforce
=on|off
][,queues
=n
]
2817 Establish a vhost
-user netdev
, backed by a chardev @
var{id
}. The chardev should
2818 be a unix domain socket backed one
. The vhost
-user uses a specifically defined
2819 protocol to pass vhost ioctl replacement messages to an application on the other
2820 end of the socket
. On non
-MSIX guests
, the feature can be forced with
2821 @
var{vhostforce
}. Use
'queues=@var{n}' to specify the number of queues to
2822 be created
for multiqueue vhost
-user
.
2826 qemu
-m
512 -object memory
-backend
-file
,id
=mem
,size
=512M
,mem
-path
=/hugetlbfs
,share
=on \
2827 -numa node
,memdev
=mem \
2828 -chardev socket
,id
=chr0
,path
=/path
/to
/socket \
2829 -netdev type
=vhost
-user
,id
=net0
,chardev
=chr0 \
2830 -device virtio
-net
-pci
,netdev
=net0
2833 @item
-netdev hubport
,id
=@
var{id
},hubid
=@
var{hubid
}[,netdev
=@
var{nd
}]
2835 Create a hub port on the emulated hub with ID @
var{hubid
}.
2837 The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a
2838 single netdev
. Alternatively
, you can also connect the hubport to another
2839 netdev with ID @
var{nd
} by
using the @option
{netdev
=@
var{nd
}} option
.
2841 @item
-net nic
[,netdev
=@
var{nd
}][,macaddr
=@
var{mac
}][,model
=@
var{type
}] [,name
=@
var{name
}][,addr
=@
var{addr
}][,vectors
=@
var{v
}]
2843 Legacy option to configure or create an on
-board (or machine
default) Network
2844 Interface
Card(NIC
) and connect it either to the emulated hub with ID
0 (i
.e
.
2845 the
default hub
), or to the netdev @
var{nd
}.
2846 The NIC is an e1000 by
default on the PC target
. Optionally
, the MAC address
2847 can be changed to @
var{mac
}, the device address set to @
var{addr
} (PCI cards
2848 only
), and a @
var{name
} can be assigned
for use
in monitor commands
.
2849 Optionally
, for PCI cards
, you can specify the number @
var{v
} of MSI
-X vectors
2850 that the card should have
; this option currently only affects virtio cards
; set
2851 @
var{v
} = 0 to disable MSI
-X
. If no @option
{-net
} option is specified
, a single
2852 NIC is created
. QEMU can emulate several different models of network card
.
2853 Use @code
{-net nic
,model
=help
} for a list of available devices
for your target
.
2855 @item
-net user|tap|bridge|socket|l2tpv3|vde
[,...][,name
=@
var{name
}]
2856 Configure a host network
backend (with the options corresponding to the same
2857 @option
{-netdev
} option
) and connect it to the emulated hub
0 (the
default
2858 hub
). Use @
var{name
} to specify the name of the hub port
.
2866 DEFHEADING(Character device options
:)
2868 DEF("chardev", HAS_ARG
, QEMU_OPTION_chardev
,
2870 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2871 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
2872 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
2873 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
2874 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
2875 " [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
2876 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
2877 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
2878 " [,logfile=PATH][,logappend=on|off]\n"
2879 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2880 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
2881 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2882 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
2883 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2884 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2886 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2887 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2889 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2890 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
2892 #ifdef CONFIG_BRLAPI
2893 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2895 #
if defined(__linux__
) ||
defined(__sun__
) ||
defined(__FreeBSD__
) \
2896 ||
defined(__NetBSD__
) ||
defined(__OpenBSD__
) ||
defined(__DragonFly__
)
2897 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2898 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2900 #
if defined(__linux__
) ||
defined(__FreeBSD__
) ||
defined(__DragonFly__
)
2901 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2902 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2904 #
if defined(CONFIG_SPICE
)
2905 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2906 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2913 The general form of a character device option is
:
2915 @item
-chardev @
var{backend
},id
=@
var{id
}[,mux
=on|off
][,@
var{options
}]
2936 The specific backend will determine the applicable options
.
2938 Use @code
{-chardev help
} to print all available chardev backend types
.
2940 All devices must have an id
, which can be any string up to
127 characters long
.
2941 It is used to uniquely identify
this device
in other command line directives
.
2943 A character device may be used
in multiplexing mode by multiple front
-ends
.
2944 Specify @option
{mux
=on
} to enable
this mode
.
2945 A multiplexer is a
"1:N" device
, and
here the
"1" end is your specified chardev
2946 backend
, and the
"N" end is the various parts of QEMU that can talk to a chardev
.
2947 If you create a chardev with @option
{id
=myid
} and @option
{mux
=on
}, QEMU will
2948 create a multiplexer with your specified ID
, and you can then configure multiple
2949 front ends to use that chardev ID
for their input
/output
. Up to four different
2950 front ends can be connected to a single multiplexed chardev
. (Without
2951 multiplexing enabled
, a chardev can only be used by a single front end
.)
2952 For instance you could use
this to allow a single stdio chardev to be used by
2953 two serial ports and the QEMU monitor
:
2956 -chardev stdio
,mux
=on
,id
=char0 \
2957 -mon chardev
=char0
,mode
=readline \
2958 -serial chardev
:char0 \
2959 -serial chardev
:char0
2962 You can have more than one multiplexer
in a system configuration
; for instance
2963 you could have a TCP port multiplexed between UART
0 and UART
1, and stdio
2964 multiplexed between the QEMU monitor and a parallel port
:
2967 -chardev stdio
,mux
=on
,id
=char0 \
2968 -mon chardev
=char0
,mode
=readline \
2969 -parallel chardev
:char0 \
2970 -chardev tcp
,...,mux
=on
,id
=char1 \
2971 -serial chardev
:char1 \
2972 -serial chardev
:char1
2975 When you
're using a multiplexed character device, some escape sequences are
2976 interpreted in the input. @xref{mux_keys, Keys in the character backend
2979 Note that some other command line options may implicitly create multiplexed
2980 character backends; for instance @option{-serial mon:stdio} creates a
2981 multiplexed stdio backend connected to the serial port and the QEMU monitor,
2982 and @option{-nographic} also multiplexes the console and the monitor to
2985 There is currently no support for multiplexing in the other direction
2986 (where a single QEMU front end takes input and output from multiple chardevs).
2988 Every backend supports the @option{logfile} option, which supplies the path
2989 to a file to record all data transmitted via the backend. The @option{logappend}
2990 option controls whether the log file will be truncated or appended to when
2995 The available backends are:
2998 @item -chardev null,id=@var{id}
2999 A void device. This device will not emit any data, and will drop any data it
3000 receives. The null backend does not take any options.
3002 @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}]
3004 Create a two-way stream socket, which can be either a TCP or a unix socket. A
3005 unix socket will be created if @option{path} is specified. Behaviour is
3006 undefined if TCP options are specified for a unix socket.
3008 @option{server} specifies that the socket shall be a listening socket.
3010 @option{nowait} specifies that QEMU should not block waiting for a client to
3011 connect to a listening socket.
3013 @option{telnet} specifies that traffic on the socket should interpret telnet
3016 @option{websocket} specifies that the socket uses WebSocket protocol for
3019 @option{reconnect} sets the timeout for reconnecting on non-server sockets when
3020 the remote end goes away. qemu will delay this many seconds and then attempt
3021 to reconnect. Zero disables reconnecting, and is the default.
3023 @option{tls-creds} requests enablement of the TLS protocol for encryption,
3024 and specifies the id of the TLS credentials to use for the handshake. The
3025 credentials must be previously created with the @option{-object tls-creds}
3028 @option{tls-auth} provides the ID of the QAuthZ authorization object against
3029 which the client's x509 distinguished name will be validated
. This object is
3030 only resolved at time of use
, so can be deleted and recreated on the fly
3031 while the chardev server is active
. If missing
, it will
default to denying
3034 TCP and unix socket options are given below
:
3038 @item TCP options
: port
=@
var{port
}[,host
=@
var{host
}][,to
=@
var{to
}][,ipv4
][,ipv6
][,nodelay
]
3040 @option
{host
} for a listening socket specifies the local address to be bound
.
3041 For a connecting socket species the remote host to connect to
. @option
{host
} is
3042 optional
for listening sockets
. If not specified it defaults to @code
{0.0.0.0}.
3044 @option
{port
} for a listening socket specifies the local port to be bound
. For a
3045 connecting socket specifies the port on the remote host to connect to
.
3046 @option
{port
} can be given as either a port number or a service name
.
3047 @option
{port
} is required
.
3049 @option
{to
} is only relevant to listening sockets
. If it is specified
, and
3050 @option
{port
} cannot be bound
, QEMU will attempt to bind to subsequent ports up
3051 to and including @option
{to
} until it succeeds
. @option
{to
} must be specified
3054 @option
{ipv4
} and @option
{ipv6
} specify that either IPv4 or IPv6 must be used
.
3055 If neither is specified the socket may use either protocol
.
3057 @option
{nodelay
} disables the Nagle algorithm
.
3059 @item unix options
: path
=@
var{path
}
3061 @option
{path
} specifies the local path of the unix socket
. @option
{path
} is
3066 @item
-chardev udp
,id
=@
var{id
}[,host
=@
var{host
}],port
=@
var{port
}[,localaddr
=@
var{localaddr
}][,localport
=@
var{localport
}][,ipv4
][,ipv6
]
3068 Sends all traffic from the guest to a remote host over UDP
.
3070 @option
{host
} specifies the remote host to connect to
. If not specified it
3071 defaults to @code
{localhost
}.
3073 @option
{port
} specifies the port on the remote host to connect to
. @option
{port
}
3076 @option
{localaddr
} specifies the local address to bind to
. If not specified it
3077 defaults to @code
{0.0.0.0}.
3079 @option
{localport
} specifies the local port to bind to
. If not specified any
3080 available local port will be used
.
3082 @option
{ipv4
} and @option
{ipv6
} specify that either IPv4 or IPv6 must be used
.
3083 If neither is specified the device may use either protocol
.
3085 @item
-chardev msmouse
,id
=@
var{id
}
3087 Forward QEMU
's emulated msmouse events to the guest. @option{msmouse} does not
3090 @item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]]
3092 Connect to a QEMU text console. @option{vc} may optionally be given a specific
3095 @option{width} and @option{height} specify the width and height respectively of
3096 the console, in pixels.
3098 @option{cols} and @option{rows} specify that the console be sized to fit a text
3099 console with the given dimensions.
3101 @item -chardev ringbuf,id=@var{id}[,size=@var{size}]
3103 Create a ring buffer with fixed size @option{size}.
3104 @var{size} must be a power of two and defaults to @code{64K}.
3106 @item -chardev file,id=@var{id},path=@var{path}
3108 Log all traffic received from the guest to a file.
3110 @option{path} specifies the path of the file to be opened. This file will be
3111 created if it does not already exist, and overwritten if it does. @option{path}
3114 @item -chardev pipe,id=@var{id},path=@var{path}
3116 Create a two-way connection to the guest. The behaviour differs slightly between
3117 Windows hosts and other hosts:
3119 On Windows, a single duplex pipe will be created at
3120 @file{\\.pipe\@option{path}}.
3122 On other hosts, 2 pipes will be created called @file{@option{path}.in} and
3123 @file{@option{path}.out}. Data written to @file{@option{path}.in} will be
3124 received by the guest. Data written by the guest can be read from
3125 @file{@option{path}.out}. QEMU will not create these fifos, and requires them to
3128 @option{path} forms part of the pipe path as described above. @option{path} is
3131 @item -chardev console,id=@var{id}
3133 Send traffic from the guest to QEMU's standard output
. @option
{console
} does not
3136 @option
{console
} is only available on Windows hosts
.
3138 @item
-chardev serial
,id
=@
var{id
},path
=@option
{path
}
3140 Send traffic from the guest to a serial device on the host
.
3142 On Unix hosts serial will actually accept any tty device
,
3143 not only serial lines
.
3145 @option
{path
} specifies the name of the serial device to open
.
3147 @item
-chardev pty
,id
=@
var{id
}
3149 Create a
new pseudo
-terminal on the host and connect to it
. @option
{pty
} does
3150 not take any options
.
3152 @option
{pty
} is not available on Windows hosts
.
3154 @item
-chardev stdio
,id
=@
var{id
}[,signal
=on|off
]
3155 Connect to standard input and standard output of the QEMU process
.
3157 @option
{signal
} controls
if signals are enabled on the terminal
, that includes
3158 exiting QEMU with the key sequence @key
{Control
-c
}. This option is enabled by
3159 default, use @option
{signal
=off
} to disable it
.
3161 @item
-chardev braille
,id
=@
var{id
}
3163 Connect to a local BrlAPI server
. @option
{braille
} does not take any options
.
3165 @item
-chardev tty
,id
=@
var{id
},path
=@
var{path
}
3167 @option
{tty
} is only available on Linux
, Sun
, FreeBSD
, NetBSD
, OpenBSD and
3168 DragonFlyBSD hosts
. It is an alias
for @option
{serial
}.
3170 @option
{path
} specifies the path to the tty
. @option
{path
} is required
.
3172 @item
-chardev parallel
,id
=@
var{id
},path
=@
var{path
}
3173 @itemx
-chardev parport
,id
=@
var{id
},path
=@
var{path
}
3175 @option
{parallel
} is only available on Linux
, FreeBSD and DragonFlyBSD hosts
.
3177 Connect to a local parallel port
.
3179 @option
{path
} specifies the path to the parallel port device
. @option
{path
} is
3182 @item
-chardev spicevmc
,id
=@
var{id
},debug
=@
var{debug
},name
=@
var{name
}
3184 @option
{spicevmc
} is only available when spice support is built
in.
3186 @option
{debug
} debug level
for spicevmc
3188 @option
{name
} name of spice channel to connect to
3190 Connect to a spice virtual machine channel
, such as vdiport
.
3192 @item
-chardev spiceport
,id
=@
var{id
},debug
=@
var{debug
},name
=@
var{name
}
3194 @option
{spiceport
} is only available when spice support is built
in.
3196 @option
{debug
} debug level
for spicevmc
3198 @option
{name
} name of spice port to connect to
3200 Connect to a spice port
, allowing a Spice client to handle the traffic
3201 identified by a
name (preferably a fqdn
).
3210 DEFHEADING(TPM device options
:)
3212 DEF("tpmdev", HAS_ARG
, QEMU_OPTION_tpmdev
, \
3213 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3214 " use path to provide path to a character device; default is /dev/tpm0\n"
3215 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3216 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3217 "-tpmdev emulator,id=id,chardev=dev\n"
3218 " configure the TPM device using chardev backend\n",
3222 The general form of a TPM device option is
:
3225 @item
-tpmdev @
var{backend
},id
=@
var{id
}[,@
var{options
}]
3228 The specific backend type will determine the applicable options
.
3229 The @code
{-tpmdev
} option creates the TPM backend and requires a
3230 @code
{-device
} option that specifies the TPM frontend
interface model
.
3232 Use @code
{-tpmdev help
} to print all available TPM backend types
.
3236 The available backends are
:
3240 @item
-tpmdev passthrough
,id
=@
var{id
},path
=@
var{path
},cancel
-path
=@
var{cancel
-path
}
3242 (Linux
-host only
) Enable access to the host
's TPM using the passthrough
3245 @option{path} specifies the path to the host's TPM device
, i
.e
., on
3246 a Linux host
this would be @code
{/dev
/tpm0
}.
3247 @option
{path
} is optional and by
default @code
{/dev
/tpm0
} is used
.
3249 @option
{cancel
-path
} specifies the path to the host TPM device
's sysfs
3250 entry allowing for cancellation of an ongoing TPM command.
3251 @option{cancel-path} is optional and by default QEMU will search for the
3254 Some notes about using the host's TPM with the passthrough driver
:
3256 The TPM device accessed by the passthrough driver must not be
3257 used by any other application on the host
.
3259 Since the host
's firmware (BIOS/UEFI) has already initialized the TPM,
3260 the VM's
firmware (BIOS
/UEFI
) will not be able to initialize the
3261 TPM again and may therefore not show a TPM
-specific menu that would
3262 otherwise allow the user to configure the TPM
, e
.g
., allow the user to
3263 enable
/disable or activate
/deactivate the TPM
.
3264 Further
, if TPM ownership is released from within a VM then the host
's TPM
3265 will get disabled and deactivated. To enable and activate the
3266 TPM again afterwards, the host has to be rebooted and the user is
3267 required to enter the firmware's menu to enable and activate the TPM
.
3268 If the TPM is left disabled and
/or deactivated most TPM commands will fail
.
3270 To create a passthrough TPM use the following two options
:
3272 -tpmdev passthrough
,id
=tpm0
-device tpm
-tis
,tpmdev
=tpm0
3274 Note that the @code
{-tpmdev
} id is @code
{tpm0
} and is referenced by
3275 @code
{tpmdev
=tpm0
} in the device option
.
3277 @item
-tpmdev emulator
,id
=@
var{id
},chardev
=@
var{dev
}
3279 (Linux
-host only
) Enable access to a TPM emulator
using Unix domain socket based
3282 @option
{chardev
} specifies the unique ID of a character device backend that provides connection to the software TPM server
.
3284 To create a TPM emulator backend device with chardev socket backend
:
3287 -chardev socket
,id
=chrtpm
,path
=/tmp
/swtpm
-sock
-tpmdev emulator
,id
=tpm0
,chardev
=chrtpm
-device tpm
-tis
,tpmdev
=tpm0
3300 DEFHEADING(Linux
/Multiboot boot specific
:)
3303 When
using these options
, you can use a given Linux or Multiboot
3304 kernel without installing it
in the disk image
. It can be useful
3305 for easier testing of various kernels
.
3310 DEF("kernel", HAS_ARG
, QEMU_OPTION_kernel
, \
3311 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL
)
3313 @item
-kernel @
var{bzImage
}
3315 Use @
var{bzImage
} as kernel image
. The kernel can be either a Linux kernel
3316 or
in multiboot format
.
3319 DEF("append", HAS_ARG
, QEMU_OPTION_append
, \
3320 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL
)
3322 @item
-append @
var{cmdline
}
3324 Use @
var{cmdline
} as kernel command line
3327 DEF("initrd", HAS_ARG
, QEMU_OPTION_initrd
, \
3328 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL
)
3330 @item
-initrd @
var{file
}
3332 Use @
var{file
} as initial ram disk
.
3334 @item
-initrd
"@var{file1} arg=foo,@var{file2}"
3336 This syntax is only available with multiboot
.
3338 Use @
var{file1
} and @
var{file2
} as modules and pass arg
=foo as parameter to the
3342 DEF("dtb", HAS_ARG
, QEMU_OPTION_dtb
, \
3343 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL
)
3345 @item
-dtb @
var{file
}
3347 Use @
var{file
} as a device tree
binary (dtb
) image and pass it to the kernel
3356 DEFHEADING(Debug
/Expert options
:)
3361 DEF("fw_cfg", HAS_ARG
, QEMU_OPTION_fwcfg
,
3362 "-fw_cfg [name=]<name>,file=<file>\n"
3363 " add named fw_cfg entry with contents from file\n"
3364 "-fw_cfg [name=]<name>,string=<str>\n"
3365 " add named fw_cfg entry with contents from string\n",
3369 @item
-fw_cfg
[name
=]@
var{name
},file
=@
var{file
}
3371 Add named fw_cfg entry with contents from file @
var{file
}.
3373 @item
-fw_cfg
[name
=]@
var{name
},string
=@
var{str
}
3374 Add named fw_cfg entry with contents from string @
var{str
}.
3376 The terminating NUL character of the contents of @
var{str
} will not be
3377 included as part of the fw_cfg item data
. To insert contents with
3378 embedded NUL characters
, you have to use the @
var{file
} parameter
.
3380 The fw_cfg entries are passed by QEMU through to the guest
.
3384 -fw_cfg name
=opt
/com
.mycompany
/blob
,file
=./my_blob
.bin
3386 creates an fw_cfg entry named opt
/com
.mycompany
/blob with contents
3391 DEF("serial", HAS_ARG
, QEMU_OPTION_serial
, \
3392 "-serial dev redirect the serial port to char device 'dev'\n",
3395 @item
-serial @
var{dev
}
3397 Redirect the virtual serial port to host character device
3398 @
var{dev
}. The
default device is @code
{vc
} in graphical mode and
3399 @code
{stdio
} in non graphical mode
.
3401 This option can be used several times to simulate up to
4 serial
3404 Use @code
{-serial none
} to disable all serial ports
.
3406 Available character devices are
:
3408 @item vc
[:@
var{W
}x@
var{H
}]
3409 Virtual console
. Optionally
, a width and height can be given
in pixel with
3413 It is also possible to specify width or height
in characters
:
3418 [Linux only
] Pseudo
TTY (a
new PTY is automatically allocated
)
3420 No device is allocated
.
3423 @item chardev
:@
var{id
}
3424 Use a named character device defined with the @code
{-chardev
} option
.
3426 [Linux only
] Use host tty
, e
.g
. @file
{/dev
/ttyS0
}. The host serial port
3427 parameters are set according to the emulated ones
.
3428 @item
/dev
/parport@
var{N
}
3429 [Linux only
, parallel port only
] Use host parallel port
3430 @
var{N
}. Currently SPP and EPP parallel port features can be used
.
3431 @item file
:@
var{filename
}
3432 Write output to @
var{filename
}. No character can be read
.
3434 [Unix only
] standard input
/output
3435 @item pipe
:@
var{filename
}
3436 name pipe @
var{filename
}
3438 [Windows only
] Use host serial port @
var{n
}
3439 @item udp
:[@
var{remote_host
}]:@
var{remote_port
}[@@
[@
var{src_ip
}]:@
var{src_port
}]
3440 This
implements UDP Net Console
.
3441 When @
var{remote_host
} or @
var{src_ip
} are not specified
3442 they
default to @code
{0.0.0.0}.
3443 When not
using a specified @
var{src_port
} a random port is automatically chosen
.
3445 If you just want a simple readonly console you can use @code
{netcat
} or
3446 @code
{nc
}, by starting QEMU with
: @code
{-serial udp
::4555} and nc as
:
3447 @code
{nc
-u
-l
-p
4555}. Any time QEMU writes something to that port it
3448 will appear
in the netconsole session
.
3450 If you plan to send characters back via netconsole or you want to stop
3451 and start QEMU a lot of times
, you should have QEMU use the same
3452 source port each time by
using something like @code
{-serial
3453 udp
::4555@@
:4556} to QEMU
. Another approach is to use a patched
3454 version of netcat which can listen to a TCP port and send and receive
3455 characters via udp
. If you have a patched version of netcat which
3456 activates telnet remote echo and single char transfer
, then you can
3457 use the following options to set up a netcat redirector to allow
3458 telnet on port
5555 to access the QEMU port
.
3461 -serial udp
::4555@@
:4556
3462 @item netcat options
:
3463 -u
-P
4555 -L
0.0.0.0:4556 -t
-p
5555 -I
-T
3464 @item telnet options
:
3468 @item tcp
:[@
var{host
}]:@
var{port
}[,@
var{server
}][,nowait
][,nodelay
][,reconnect
=@
var{seconds
}]
3469 The TCP Net Console has two modes of operation
. It can send the serial
3470 I
/O to a location or wait
for a connection from a location
. By
default
3471 the TCP Net Console is sent to @
var{host
} at the @
var{port
}. If you use
3472 the @
var{server
} option QEMU will wait
for a client socket application
3473 to connect to the port before continuing
, unless the @code
{nowait
}
3474 option was specified
. The @code
{nodelay
} option disables the Nagle buffering
3475 algorithm
. The @code
{reconnect
} option only applies
if @
var{noserver
} is
3476 set
, if the connection goes down it will attempt to reconnect at the
3477 given interval
. If @
var{host
} is omitted
, 0.0.0.0 is assumed
. Only
3478 one TCP connection at a time is accepted
. You can use @code
{telnet
} to
3479 connect to the corresponding character device
.
3481 @item Example to send tcp console to
192.168.0.2 port
4444
3482 -serial tcp
:192.168.0.2:4444
3483 @item Example to listen and wait on port
4444 for connection
3484 -serial tcp
::4444,server
3485 @item Example to not wait and listen on ip
192.168.0.100 port
4444
3486 -serial tcp
:192.168.0.100:4444,server
,nowait
3489 @item telnet
:@
var{host
}:@
var{port
}[,server
][,nowait
][,nodelay
]
3490 The telnet protocol is used instead of raw tcp sockets
. The options
3491 work the same as
if you had specified @code
{-serial tcp
}. The
3492 difference is that the port acts like a telnet server or client
using
3493 telnet option negotiation
. This will also allow you to send the
3494 MAGIC_SYSRQ sequence
if you use a telnet that supports sending the
break
3495 sequence
. Typically
in unix telnet you
do it with Control
-] and then
3496 type
"send break" followed by pressing the enter key
.
3498 @item websocket
:@
var{host
}:@
var{port
},server
[,nowait
][,nodelay
]
3499 The WebSocket protocol is used instead of raw tcp socket
. The port acts as
3500 a WebSocket server
. Client mode is not supported
.
3502 @item unix
:@
var{path
}[,server
][,nowait
][,reconnect
=@
var{seconds
}]
3503 A unix domain socket is used instead of a tcp socket
. The option works the
3504 same as
if you had specified @code
{-serial tcp
} except the unix domain socket
3505 @
var{path
} is used
for connections
.
3507 @item mon
:@
var{dev_string
}
3508 This is a special option to allow the monitor to be multiplexed onto
3509 another serial port
. The monitor is accessed with key sequence of
3510 @key
{Control
-a
} and then pressing @key
{c
}.
3511 @
var{dev_string
} should be any one of the serial devices specified
3512 above
. An example to multiplex the monitor onto a telnet server
3513 listening on port
4444 would be
:
3515 @item
-serial mon
:telnet
::4444,server
,nowait
3517 When the monitor is multiplexed to stdio
in this way
, Ctrl
+C will not terminate
3518 QEMU any more but will be passed to the guest instead
.
3521 Braille device
. This will use BrlAPI to display the braille output on a real
3525 Three button serial mouse
. Configure the guest to use Microsoft protocol
.
3529 DEF("parallel", HAS_ARG
, QEMU_OPTION_parallel
, \
3530 "-parallel dev redirect the parallel port to char device 'dev'\n",
3533 @item
-parallel @
var{dev
}
3535 Redirect the virtual parallel port to host device @
var{dev
} (same
3536 devices as the serial port
). On Linux hosts
, @file
{/dev
/parportN
} can
3537 be used to use hardware devices connected on the corresponding host
3540 This option can be used several times to simulate up to
3 parallel
3543 Use @code
{-parallel none
} to disable all parallel ports
.
3546 DEF("monitor", HAS_ARG
, QEMU_OPTION_monitor
, \
3547 "-monitor dev redirect the monitor to char device 'dev'\n",
3550 @item
-monitor @
var{dev
}
3552 Redirect the monitor to host device @
var{dev
} (same devices as the
3554 The
default device is @code
{vc
} in graphical mode and @code
{stdio
} in
3556 Use @code
{-monitor none
} to disable the
default monitor
.
3558 DEF("qmp", HAS_ARG
, QEMU_OPTION_qmp
, \
3559 "-qmp dev like -monitor but opens in 'control' mode\n",
3562 @item
-qmp @
var{dev
}
3564 Like
-monitor but opens
in 'control' mode
.
3566 DEF("qmp-pretty", HAS_ARG
, QEMU_OPTION_qmp_pretty
, \
3567 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3570 @item
-qmp
-pretty @
var{dev
}
3572 Like
-qmp but uses pretty JSON formatting
.
3575 DEF("mon", HAS_ARG
, QEMU_OPTION_mon
, \
3576 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL
)
3578 @item
-mon
[chardev
=]name
[,mode
=readline|control
][,pretty
[=on|off
]]
3580 Setup monitor on chardev @
var{name
}. @code
{pretty
} turns on JSON pretty printing
3581 easing human reading and debugging
.
3584 DEF("debugcon", HAS_ARG
, QEMU_OPTION_debugcon
, \
3585 "-debugcon dev redirect the debug console to char device 'dev'\n",
3588 @item
-debugcon @
var{dev
}
3590 Redirect the debug console to host device @
var{dev
} (same devices as the
3591 serial port
). The debug console is an I
/O port which is typically port
3592 0xe9; writing to that I
/O port sends output to
this device
.
3593 The
default device is @code
{vc
} in graphical mode and @code
{stdio
} in
3597 DEF("pidfile", HAS_ARG
, QEMU_OPTION_pidfile
, \
3598 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL
)
3600 @item
-pidfile @
var{file
}
3602 Store the QEMU process PID
in @
var{file
}. It is useful
if you launch QEMU
3606 DEF("singlestep", 0, QEMU_OPTION_singlestep
, \
3607 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL
)
3611 Run the emulation
in single step mode
.
3614 DEF("preconfig", 0, QEMU_OPTION_preconfig
, \
3615 "--preconfig pause QEMU before machine is initialized (experimental)\n",
3620 Pause QEMU
for interactive configuration before the machine is created
,
3621 which allows querying and configuring properties that will affect
3622 machine initialization
. Use QMP command
'x-exit-preconfig' to exit
3623 the preconfig state and move to the next
state (i
.e
. run guest
if -S
3624 isn
't used or pause the second time if -S is used). This option is
3628 DEF("S", 0, QEMU_OPTION_S, \
3629 "-S freeze CPU at startup (use 'c
' to start execution)\n",
3634 Do not start CPU at startup (you must type 'c
' in the monitor).
3637 DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,
3638 "-realtime [mlock=on|off]\n"
3639 " run qemu with realtime features\n"
3640 " mlock=on|off controls mlock support (default: on)\n",
3643 @item -realtime mlock=on|off
3645 Run qemu with realtime features.
3646 mlocking qemu and guest memory can be enabled via @option{mlock=on}
3647 (enabled by default).
3650 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3651 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3652 " run qemu with overcommit hints\n"
3653 " mem-lock=on|off controls memory lock support (default: off)\n"
3654 " cpu-pm=on|off controls cpu power management (default: off)\n",
3657 @item -overcommit mem-lock=on|off
3658 @item -overcommit cpu-pm=on|off
3660 Run qemu with hints about host resource overcommit. The default is
3661 to assume that host overcommits all resources.
3663 Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled
3664 by default). This works when host memory is not overcommitted and reduces the
3665 worst-case latency for guest. This is equivalent to @option{realtime}.
3667 Guest ability to manage power state of host cpus (increasing latency for other
3668 processes on the same host cpu, but decreasing latency for guest) can be
3669 enabled via @option{cpu-pm=on} (disabled by default). This works best when
3670 host CPU is not overcommitted. When used, host estimates of CPU cycle and power
3671 utilization will be incorrect, not taking into account guest idle time.
3674 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3675 "-gdb dev wait for gdb connection on 'dev
'\n", QEMU_ARCH_ALL)
3677 @item -gdb @var{dev}
3679 Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3680 connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3681 stdio are reasonable use case. The latter is allowing to start QEMU from
3682 within gdb and establish the connection via a pipe:
3684 (gdb) target remote | exec @value{qemu_system} -gdb stdio ...
3688 DEF("s", 0, QEMU_OPTION_s, \
3689 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3694 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3695 (@pxref{gdb_usage}).
3698 DEF("d", HAS_ARG, QEMU_OPTION_d, \
3699 "-d item1,... enable logging of specified items (use '-d help
' for a list of log items)\n",
3702 @item -d @var{item1}[,...]
3704 Enable logging of specified items. Use '-d help
' for a list of log items.
3707 DEF("D", HAS_ARG, QEMU_OPTION_D, \
3708 "-D logfile output log to logfile (default stderr)\n",
3711 @item -D @var{logfile}
3713 Output log in @var{logfile} instead of to stderr
3716 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3717 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3720 @item -dfilter @var{range1}[,...]
3722 Filter debug output to that relevant to a range of target addresses. The filter
3723 spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3724 @var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3725 addresses and sizes required. For example:
3727 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3729 Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3730 the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3731 block starting at 0xffffffc00005f000.
3734 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
3735 "-seed number seed the pseudo-random number generator\n",
3738 @item -seed @var{number}
3740 Force the guest to use a deterministic pseudo-random number generator, seeded
3741 with @var{number}. This does not affect crypto routines within the host.
3744 DEF("L", HAS_ARG, QEMU_OPTION_L, \
3745 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
3750 Set the directory for the BIOS, VGA BIOS and keymaps.
3752 To list all the data directories, use @code{-L help}.
3755 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3756 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
3758 @item -bios @var{file}
3760 Set the filename for the BIOS.
3763 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3764 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3768 Enable KVM full virtualization support. This option is only available
3769 if KVM support is enabled when compiling.
3772 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3773 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL)
3774 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3775 "-xen-attach attach to existing xen domain\n"
3776 " libxl will use this when starting QEMU\n",
3778 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3779 "-xen-domid-restrict restrict set of available xen operations\n"
3780 " to specified domain id. (Does not affect\n"
3781 " xenpv machine type).\n",
3784 @item -xen-domid @var{id}
3786 Specify xen guest domain @var{id} (XEN only).
3789 Attach to existing xen domain.
3790 libxl will use this when starting QEMU (XEN only).
3791 @findex -xen-domid-restrict
3792 Restrict set of available xen operations to specified domain id (XEN only).
3795 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3796 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
3800 Exit instead of rebooting.
3803 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
3804 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
3807 @findex -no-shutdown
3808 Don't exit QEMU on guest shutdown
, but instead only stop the emulation
.
3809 This allows
for instance switching to monitor to commit changes to the
3813 DEF("loadvm", HAS_ARG
, QEMU_OPTION_loadvm
, \
3814 "-loadvm [tag|id]\n" \
3815 " start right away with a saved state (loadvm in monitor)\n",
3818 @item
-loadvm @
var{file
}
3820 Start right away with a saved
state (@code
{loadvm
} in monitor
)
3824 DEF("daemonize", 0, QEMU_OPTION_daemonize
, \
3825 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL
)
3830 Daemonize the QEMU process after initialization
. QEMU will not detach from
3831 standard IO until it is ready to receive connections on any of its devices
.
3832 This option is a useful way
for external programs to launch QEMU without having
3833 to cope with initialization race conditions
.
3836 DEF("option-rom", HAS_ARG
, QEMU_OPTION_option_rom
, \
3837 "-option-rom rom load a file, rom, into the option ROM space\n",
3840 @item
-option
-rom @
var{file
}
3842 Load the contents of @
var{file
} as an option ROM
.
3843 This option is useful to load things like EtherBoot
.
3846 DEF("rtc", HAS_ARG
, QEMU_OPTION_rtc
, \
3847 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
3848 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
3853 @item
-rtc
[base
=utc|localtime|@
var{datetime
}][,clock
=host|rt|vm
][,driftfix
=none|slew
]
3855 Specify @option
{base
} as @code
{utc
} or @code
{localtime
} to let the RTC start at the current
3856 UTC or local time
, respectively
. @code
{localtime
} is required
for correct date
in
3857 MS
-DOS or Windows
. To start at a specific point
in time
, provide @
var{datetime
} in the
3858 format @code
{2006-06-17T16
:01:21} or @code
{2006-06-17}. The
default base is UTC
.
3860 By
default the RTC is driven by the host system time
. This allows
using of the
3861 RTC as accurate reference clock inside the guest
, specifically
if the host
3862 time is smoothly following an accurate external reference clock
, e
.g
. via NTP
.
3863 If you want to isolate the guest time from the host
, you can set @option
{clock
}
3864 to @code
{rt
} instead
, which provides a host monotonic clock
if host support it
.
3865 To even prevent the RTC from progressing during suspension
, you can set @option
{clock
}
3866 to @code
{vm
} (virtual clock
). @samp
{clock
=vm
} is recommended especially
in
3867 icount mode
in order to preserve determinism
; however
, note that
in icount mode
3868 the speed of the virtual clock is variable and can
in general differ from the
3871 Enable @option
{driftfix
} (i386 targets only
) if you experience time drift problems
,
3872 specifically with Windows
' ACPI HAL. This option will try to figure out how
3873 many timer interrupts were not processed by the Windows guest and will
3877 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
3878 "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \
3879 " enable virtual instruction counter with 2^N clock ticks per\n" \
3880 " instruction, enable aligning the host and virtual clocks\n" \
3881 " or disable real time cpu sleeping\n", QEMU_ARCH_ALL)
3883 @item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3885 Enable virtual instruction counter. The virtual cpu will execute one
3886 instruction every 2^@var{N} ns of virtual time. If @code{auto} is specified
3887 then the virtual cpu speed will be automatically adjusted to keep virtual
3888 time within a few seconds of real time.
3890 When the virtual cpu is sleeping, the virtual time will advance at default
3891 speed unless @option{sleep=on|off} is specified.
3892 With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3893 instantly whenever the virtual cpu goes to sleep mode and will not advance
3894 if no timer is enabled. This behavior give deterministic execution times from
3895 the guest point of view.
3897 Note that while this option can give deterministic behavior, it does not
3898 provide cycle accurate emulation. Modern CPUs contain superscalar out of
3899 order cores with complex cache hierarchies. The number of instructions
3900 executed often has little or no correlation with actual performance.
3902 @option{align=on} will activate the delay algorithm which will try
3903 to synchronise the host clock and the virtual clock. The goal is to
3904 have a guest running at the real frequency imposed by the shift option.
3905 Whenever the guest clock is behind the host clock and if
3906 @option{align=on} is specified then we print a message to the user
3907 to inform about the delay.
3908 Currently this option does not work when @option{shift} is @code{auto}.
3909 Note: The sync algorithm will work for those shift values for which
3910 the guest clock runs ahead of the host clock. Typically this happens
3911 when the shift value is high (how high depends on the host machine).
3913 When @option{rr} option is specified deterministic record/replay is enabled.
3914 Replay log is written into @var{filename} file in record mode and
3915 read from this file in replay mode.
3917 Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3918 at the start of execution recording. In replay mode this option is used
3919 to load the initial VM state.
3922 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
3923 "-watchdog model\n" \
3924 " enable virtual hardware watchdog [default=none]\n",
3927 @item -watchdog @var{model}
3929 Create a virtual hardware watchdog device. Once enabled (by a guest
3930 action), the watchdog must be periodically polled by an agent inside
3931 the guest or else the guest will be restarted. Choose a model for
3932 which your guest has drivers.
3934 The @var{model} is the model of hardware watchdog to emulate. Use
3935 @code{-watchdog help} to list available hardware models. Only one
3936 watchdog can be enabled for a guest.
3938 The following models may be available:
3941 iBASE 700 is a very simple ISA watchdog with a single timer.
3943 Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3944 dual-timer watchdog.
3946 A virtual watchdog for s390x backed by the diagnose 288 hypercall
3947 (currently KVM only).
3951 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
3952 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
3953 " action when watchdog fires [default=reset]\n",
3956 @item -watchdog-action @var{action}
3957 @findex -watchdog-action
3959 The @var{action} controls what QEMU will do when the watchdog timer
3962 @code{reset} (forcefully reset the guest).
3963 Other possible actions are:
3964 @code{shutdown} (attempt to gracefully shutdown the guest),
3965 @code{poweroff} (forcefully poweroff the guest),
3966 @code{inject-nmi} (inject a NMI into the guest),
3967 @code{pause} (pause the guest),
3968 @code{debug} (print a debug message and continue), or
3969 @code{none} (do nothing).
3971 Note that the @code{shutdown} action requires that the guest responds
3972 to ACPI signals, which it may not be able to do in the sort of
3973 situations where the watchdog would have expired, and thus
3974 @code{-watchdog-action shutdown} is not recommended for production use.
3979 @item -watchdog i6300esb -watchdog-action pause
3980 @itemx -watchdog ib700
3984 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
3985 "-echr chr set terminal escape character instead of ctrl-a\n",
3989 @item -echr @var{numeric_ascii_value}
3991 Change the escape character used for switching to the monitor when using
3992 monitor and serial sharing. The default is @code{0x01} when using the
3993 @code{-nographic} option. @code{0x01} is equal to pressing
3994 @code{Control-a}. You can select a different character from the ascii
3995 control keys where 1 through 26 map to Control-a through Control-z. For
3996 instance you could use the either of the following to change the escape
3997 character to Control-t.
4004 DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \
4005 "-show-cursor show cursor\n", QEMU_ARCH_ALL)
4008 @findex -show-cursor
4012 DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \
4013 "-tb-size n set TB size\n", QEMU_ARCH_ALL)
4015 @item -tb-size @var{n}
4017 Set TCG translation block cache size. Deprecated, use @samp{-accel tcg,tb-size=@var{n}}
4021 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4022 "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \
4023 "-incoming rdma:host:port[,ipv4][,ipv6]\n" \
4024 "-incoming unix:socketpath\n" \
4025 " prepare for incoming migration, listen on\n" \
4026 " specified protocol and socket address\n" \
4027 "-incoming fd:fd\n" \
4028 "-incoming exec:cmdline\n" \
4029 " accept incoming migration on given file descriptor\n" \
4030 " or from given external command\n" \
4031 "-incoming defer\n" \
4032 " wait for the URI to be specified via migrate_incoming\n",
4035 @item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
4036 @itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
4038 Prepare for incoming migration, listen on a given tcp port.
4040 @item -incoming unix:@var{socketpath}
4041 Prepare for incoming migration, listen on a given unix socket.
4043 @item -incoming fd:@var{fd}
4044 Accept incoming migration from a given filedescriptor.
4046 @item -incoming exec:@var{cmdline}
4047 Accept incoming migration as an output from specified external command.
4049 @item -incoming defer
4050 Wait for the URI to be specified via migrate_incoming. The monitor can
4051 be used to change settings (such as migration parameters) prior to issuing
4052 the migrate_incoming to allow the migration to begin.
4055 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4056 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4058 @item -only-migratable
4059 @findex -only-migratable
4060 Only allow migratable devices. Devices will not be allowed to enter an
4064 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4065 "-nodefaults don't create
default devices
\n", QEMU_ARCH_ALL)
4069 Don't create default devices. Normally, QEMU sets the default devices like serial
4070 port, parallel port, virtual console, monitor device, VGA adapter, floppy and
4071 CD-ROM drive and others. The @code{-nodefaults} option will disable all those
4076 DEF("chroot
", HAS_ARG, QEMU_OPTION_chroot, \
4077 "-chroot dir chroot to dir just before starting the VM
\n",
4081 @item -chroot @var{dir}
4083 Immediately before starting guest execution, chroot to the specified
4084 directory. Especially useful in combination with -runas.
4088 DEF("runas
", HAS_ARG, QEMU_OPTION_runas, \
4089 "-runas user change to user id user just before starting the VM
\n" \
4090 " user can be numeric uid
:gid instead
\n",
4094 @item -runas @var{user}
4096 Immediately before starting guest execution, drop root privileges, switching
4097 to the specified user.
4100 DEF("prom
-env
", HAS_ARG, QEMU_OPTION_prom_env,
4101 "-prom
-env variable
=value
\n"
4102 " set OpenBIOS nvram variables
\n",
4103 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4105 @item -prom-env @var{variable}=@var{value}
4107 Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only).
4109 DEF("semihosting
", 0, QEMU_OPTION_semihosting,
4110 "-semihosting semihosting mode
\n",
4111 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4112 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
4115 @findex -semihosting
4116 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only).
4118 DEF("semihosting
-config
", HAS_ARG, QEMU_OPTION_semihosting_config,
4119 "-semihosting
-config
[enable
=on|off
][,target
=native|gdb|auto
][,chardev
=id
][,arg
=str
[,...]]\n" \
4120 " semihosting configuration
\n",
4121 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4122 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
4124 @item -semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]
4125 @findex -semihosting-config
4126 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II only).
4128 @item target=@code{native|gdb|auto}
4129 Defines where the semihosting calls will be addressed, to QEMU (@code{native})
4130 or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
4131 during debug sessions and @code{native} otherwise.
4132 @item chardev=@var{str1}
4133 Send the output to a chardev backend output for native or auto output when not in gdb
4134 @item arg=@var{str1},arg=@var{str2},...
4135 Allows the user to pass input arguments, and can be used multiple times to build
4136 up a list. The old-style @code{-kernel}/@code{-append} method of passing a
4137 command line is still supported for backward compatibility. If both the
4138 @code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are
4139 specified, the former is passed to semihosting as it always takes precedence.
4142 DEF("old
-param
", 0, QEMU_OPTION_old_param,
4143 "-old
-param old param mode
\n", QEMU_ARCH_ARM)
4146 @findex -old-param (ARM)
4147 Old param mode (ARM only).
4150 DEF("sandbox
", HAS_ARG, QEMU_OPTION_sandbox, \
4151 "-sandbox on
[,obsolete
=allow|deny
][,elevateprivileges
=allow|deny|children
]\n" \
4152 " [,spawn
=allow|deny
][,resourcecontrol
=allow|deny
]\n" \
4153 " Enable seccomp mode
2 system call
filter (default 'off').\n" \
4154 " use
'obsolete' to allow obsolete system calls that are provided
\n" \
4155 " by the kernel
, but typically no longer used by modern
\n" \
4156 " C library implementations
.\n" \
4157 " use
'elevateprivileges' to allow or deny QEMU process to elevate
\n" \
4158 " its privileges by blacklisting all set
*uid|gid system calls
.\n" \
4159 " The value
'children' will deny set
*uid|gid system calls
for\n" \
4160 " main QEMU process but will allow forks and execves to run unprivileged
\n" \
4161 " use
'spawn' to avoid QEMU to spawn
new threads or processes by
\n" \
4162 " blacklisting
*fork and execve
\n" \
4163 " use
'resourcecontrol' to disable process affinity and schedular priority
\n",
4166 @item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}]
4168 Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
4169 disable it. The default is 'off'.
4171 @item obsolete=@var{string}
4172 Enable Obsolete system calls
4173 @item elevateprivileges=@var{string}
4174 Disable set*uid|gid system calls
4175 @item spawn=@var{string}
4176 Disable *fork and execve
4177 @item resourcecontrol=@var{string}
4178 Disable process affinity and schedular priority
4182 DEF("readconfig
", HAS_ARG, QEMU_OPTION_readconfig,
4183 "-readconfig
<file
>\n", QEMU_ARCH_ALL)
4185 @item -readconfig @var{file}
4187 Read device configuration from @var{file}. This approach is useful when you want to spawn
4188 QEMU process with many command line options but you don't want to exceed the command line
4191 DEF("writeconfig
", HAS_ARG, QEMU_OPTION_writeconfig,
4192 "-writeconfig
<file
>\n"
4193 " read
/write config file
\n", QEMU_ARCH_ALL)
4195 @item -writeconfig @var{file}
4196 @findex -writeconfig
4197 Write device configuration to @var{file}. The @var{file} can be either filename to save
4198 command line and device configuration into file or dash @code{-}) character to print the
4199 output to stdout. This can be later used as input file for @code{-readconfig} option.
4202 DEF("no
-user
-config
", 0, QEMU_OPTION_nouserconfig,
4204 " do not load
default user
-provided config files at startup
\n",
4207 @item -no-user-config
4208 @findex -no-user-config
4209 The @code{-no-user-config} option makes QEMU not load any of the user-provided
4210 config files on @var{sysconfdir}.
4213 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4214 "-trace [[enable
=]<pattern
>][,events
=<file
>][,file
=<file
>]\n"
4215 " specify tracing options
\n",
4218 HXCOMM This line is not accurate, as some sub-options are backend-specific but
4219 HXCOMM HX does not support conditional compilation of text.
4220 @item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
4222 @include qemu-option-trace.texi
4224 DEF("plugin
", HAS_ARG, QEMU_OPTION_plugin,
4225 "-plugin
[file
=]<file
>[,arg
=<string
>]\n"
4229 @item -plugin file=@var{file}[,arg=@var{string}]
4235 @item file=@var{file}
4236 Load the given plugin from a shared library file.
4237 @item arg=@var{string}
4238 Argument string passed to the plugin. (Can be given multiple times.)
4243 DEF("qtest
", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4244 DEF("qtest
-log
", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4247 DEF("enable
-fips
", 0, QEMU_OPTION_enablefips,
4248 "-enable
-fips enable FIPS
140-2 compliance
\n",
4253 @findex -enable-fips
4254 Enable FIPS 140-2 compliance mode.
4257 HXCOMM Deprecated by -accel tcg
4258 DEF("no
-kvm
", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
4260 DEF("msg
", HAS_ARG, QEMU_OPTION_msg,
4261 "-msg timestamp
[=on|off
]\n"
4262 " control error message format
\n"
4263 " timestamp
=on enables
timestamps (default: off
)\n",
4266 @item -msg timestamp[=on|off]
4268 Control error message format.
4270 @item timestamp=on|off
4271 Prefix messages with a timestamp. Default is off.
4275 DEF("dump
-vmstate
", HAS_ARG, QEMU_OPTION_dump_vmstate,
4276 "-dump
-vmstate
<file
>\n"
4277 " Output vmstate information
in JSON format to file
.\n"
4278 " Use the scripts
/vmstate
-static-checker
.py file to
\n"
4279 " check
for possible regressions
in migration code
\n"
4280 " by comparing two such vmstate dumps
.\n",
4283 @item -dump-vmstate @var{file}
4284 @findex -dump-vmstate
4285 Dump json-encoded vmstate information for current machine type to file
4289 DEF("enable
-sync
-profile
", 0, QEMU_OPTION_enable_sync_profile,
4290 "-enable
-sync
-profile
\n"
4291 " enable synchronization profiling
\n",
4294 @item -enable-sync-profile
4295 @findex -enable-sync-profile
4296 Enable synchronization profiling.
4304 DEFHEADING(Generic object creation:)
4309 DEF("object
", HAS_ARG, QEMU_OPTION_object,
4310 "-object TYPENAME
[,PROP1
=VALUE1
,...]\n"
4311 " create a
new object of type TYPENAME setting properties
\n"
4312 " in the order they are specified
. Note that the
'id'\n"
4313 " property must be set
. These objects are placed
in the
\n"
4314 " '/objects' path
.\n",
4317 @item -object @var{typename}[,@var{prop1}=@var{value1},...]
4319 Create a new object of type @var{typename} setting properties
4320 in the order they are specified. Note that the 'id'
4321 property must be set. These objects are placed in the
4326 @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}
4328 Creates a memory file backend object, which can be used to back
4329 the guest RAM with huge pages.
4331 The @option{id} parameter is a unique ID that will be used to reference this
4332 memory region when configuring the @option{-numa} argument.
4334 The @option{size} option provides the size of the memory region, and accepts
4335 common suffixes, eg @option{500M}.
4337 The @option{mem-path} provides the path to either a shared memory or huge page
4340 The @option{share} boolean option determines whether the memory
4341 region is marked as private to QEMU, or shared. The latter allows
4342 a co-operating external process to access the QEMU memory region.
4344 The @option{share} is also required for pvrdma devices due to
4345 limitations in the RDMA API provided by Linux.
4347 Setting share=on might affect the ability to configure NUMA
4348 bindings for the memory backend under some circumstances, see
4349 Documentation/vm/numa_memory_policy.txt on the Linux kernel
4350 source tree for additional details.
4352 Setting the @option{discard-data} boolean option to @var{on}
4353 indicates that file contents can be destroyed when QEMU exits,
4354 to avoid unnecessarily flushing data to the backing file. Note
4355 that @option{discard-data} is only an optimization, and QEMU
4356 might not discard file contents if it aborts unexpectedly or is
4357 terminated using SIGKILL.
4359 The @option{merge} boolean option enables memory merge, also known as
4360 MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for
4361 memory deduplication.
4363 Setting the @option{dump} boolean option to @var{off} excludes the memory from
4364 core dumps. This feature is also known as MADV_DONTDUMP.
4366 The @option{prealloc} boolean option enables memory preallocation.
4368 The @option{host-nodes} option binds the memory range to a list of NUMA host
4371 The @option{policy} option sets the NUMA policy to one of the following values:
4377 @item @var{preferred}
4378 prefer the given host node list for allocation
4381 restrict memory allocation to the given host node list
4383 @item @var{interleave}
4384 interleave memory allocations across the given host node list
4387 The @option{align} option specifies the base address alignment when
4388 QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg
4389 @option{2M}. Some backend store specified by @option{mem-path}
4390 requires an alignment different than the default one used by QEMU, eg
4391 the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4392 such cases, users can specify the required alignment via this option.
4394 The @option{pmem} option specifies whether the backing file specified
4395 by @option{mem-path} is in host persistent memory that can be accessed
4396 using the SNIA NVM programming model (e.g. Intel NVDIMM).
4397 If @option{pmem} is set to 'on', QEMU will take necessary operations to
4398 guarantee the persistence of its own writes to @option{mem-path}
4399 (e.g. in vNVDIMM label emulation and live migration).
4400 Also, we will map the backend-file with MAP_SYNC flag, which ensures the
4401 file metadata is in sync for @option{mem-path} in case of host crash
4402 or a power failure. MAP_SYNC requires support from both the host kernel
4403 (since Linux kernel 4.15) and the filesystem of @option{mem-path} mounted
4406 @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}
4408 Creates a memory backend object, which can be used to back the guest RAM.
4409 Memory backend objects offer more control than the @option{-m} option that is
4410 traditionally used to define guest RAM. Please refer to
4411 @option{memory-backend-file} for a description of the options.
4413 @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}
4415 Creates an anonymous memory file backend object, which allows QEMU to
4416 share the memory with an external process (e.g. when using
4417 vhost-user). The memory is allocated with memfd and optional
4418 sealing. (Linux only)
4420 The @option{seal} option creates a sealed-file, that will block
4421 further resizing the memory ('on' by default).
4423 The @option{hugetlb} option specify the file to be created resides in
4424 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction with
4425 the @option{hugetlb} option, the @option{hugetlbsize} option specify
4426 the hugetlb page size on systems that support multiple hugetlb page
4427 sizes (it must be a power of 2 value supported by the system).
4429 In some versions of Linux, the @option{hugetlb} option is incompatible
4430 with the @option{seal} option (requires at least Linux 4.16).
4432 Please refer to @option{memory-backend-file} for a description of the
4435 The @option{share} boolean option is @var{on} by default with memfd.
4437 @item -object rng-builtin,id=@var{id}
4439 Creates a random number generator backend which obtains entropy from
4440 QEMU builtin functions. The @option{id} parameter is a unique ID that
4441 will be used to reference this entropy backend from the @option{virtio-rng}
4442 device. By default, the @option{virtio-rng} device uses this RNG backend.
4444 @item -object rng-random,id=@var{id},filename=@var{/dev/random}
4446 Creates a random number generator backend which obtains entropy from
4447 a device on the host. The @option{id} parameter is a unique ID that
4448 will be used to reference this entropy backend from the @option{virtio-rng}
4449 device. The @option{filename} parameter specifies which file to obtain
4450 entropy from and if omitted defaults to @option{/dev/urandom}.
4452 @item -object rng-egd,id=@var{id},chardev=@var{chardevid}
4454 Creates a random number generator backend which obtains entropy from
4455 an external daemon running on the host. The @option{id} parameter is
4456 a unique ID that will be used to reference this entropy backend from
4457 the @option{virtio-rng} device. The @option{chardev} parameter is
4458 the unique ID of a character device backend that provides the connection
4461 @item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off}
4463 Creates a TLS anonymous credentials object, which can be used to provide
4464 TLS support on network backends. The @option{id} parameter is a unique
4465 ID which network backends will use to access the credentials. The
4466 @option{endpoint} is either @option{server} or @option{client} depending
4467 on whether the QEMU network backend that uses the credentials will be
4468 acting as a client or as a server. If @option{verify-peer} is enabled
4469 (the default) then once the handshake is completed, the peer credentials
4470 will be verified, though this is a no-op for anonymous credentials.
4472 The @var{dir} parameter tells QEMU where to find the credential
4473 files. For server endpoints, this directory may contain a file
4474 @var{dh-params.pem} providing diffie-hellman parameters to use
4475 for the TLS server. If the file is missing, QEMU will generate
4476 a set of DH parameters at startup. This is a computationally
4477 expensive operation that consumes random pool entropy, so it is
4478 recommended that a persistent set of parameters be generated
4481 @item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}]
4483 Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide
4484 TLS support on network backends. The @option{id} parameter is a unique
4485 ID which network backends will use to access the credentials. The
4486 @option{endpoint} is either @option{server} or @option{client} depending
4487 on whether the QEMU network backend that uses the credentials will be
4488 acting as a client or as a server. For clients only, @option{username}
4489 is the username which will be sent to the server. If omitted
4490 it defaults to ``qemu''.
4492 The @var{dir} parameter tells QEMU where to find the keys file.
4493 It is called ``@var{dir}/keys.psk'' and contains ``username:key''
4494 pairs. This file can most easily be created using the GnuTLS
4495 @code{psktool} program.
4497 For server endpoints, @var{dir} may also contain a file
4498 @var{dh-params.pem} providing diffie-hellman parameters to use
4499 for the TLS server. If the file is missing, QEMU will generate
4500 a set of DH parameters at startup. This is a computationally
4501 expensive operation that consumes random pool entropy, so it is
4502 recommended that a persistent set of parameters be generated
4505 @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}
4507 Creates a TLS anonymous credentials object, which can be used to provide
4508 TLS support on network backends. The @option{id} parameter is a unique
4509 ID which network backends will use to access the credentials. The
4510 @option{endpoint} is either @option{server} or @option{client} depending
4511 on whether the QEMU network backend that uses the credentials will be
4512 acting as a client or as a server. If @option{verify-peer} is enabled
4513 (the default) then once the handshake is completed, the peer credentials
4514 will be verified. With x509 certificates, this implies that the clients
4515 must be provided with valid client certificates too.
4517 The @var{dir} parameter tells QEMU where to find the credential
4518 files. For server endpoints, this directory may contain a file
4519 @var{dh-params.pem} providing diffie-hellman parameters to use
4520 for the TLS server. If the file is missing, QEMU will generate
4521 a set of DH parameters at startup. This is a computationally
4522 expensive operation that consumes random pool entropy, so it is
4523 recommended that a persistent set of parameters be generated
4526 For x509 certificate credentials the directory will contain further files
4527 providing the x509 certificates. The certificates must be stored
4528 in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
4529 @var{server-cert.pem} (only servers), @var{server-key.pem} (only servers),
4530 @var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients).
4532 For the @var{server-key.pem} and @var{client-key.pem} files which
4533 contain sensitive private keys, it is possible to use an encrypted
4534 version by providing the @var{passwordid} parameter. This provides
4535 the ID of a previously created @code{secret} object containing the
4536 password for decryption.
4538 The @var{priority} parameter allows to override the global default
4539 priority used by gnutls. This can be useful if the system administrator
4540 needs to use a weaker set of crypto priorities for QEMU without
4541 potentially forcing the weakness onto all applications. Or conversely
4542 if one wants wants a stronger default for QEMU than for all other
4543 applications, they can do this through this parameter. Its format is
4544 a gnutls priority string as described at
4545 @url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
4547 @item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
4549 Interval @var{t} can't be 0, this filter batches the packet delivery: all
4550 packets arriving in a given interval on netdev @var{netdevid} are delayed
4551 until the end of the interval. Interval is in microseconds.
4552 @option{status} is optional that indicate whether the netfilter is
4553 on (enabled) or off (disabled), the default status for netfilter will be 'on'.
4555 queue @var{all|rx|tx} is an option that can be applied to any netfilter.
4557 @option{all}: the filter is attached both to the receive and the transmit
4558 queue of the netdev (default).
4560 @option{rx}: the filter is attached to the receive queue of the netdev,
4561 where it will receive packets sent to the netdev.
4563 @option{tx}: the filter is attached to the transmit queue of the netdev,
4564 where it will receive packets sent by the netdev.
4566 @item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4568 filter-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.
4570 @item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4572 filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
4573 @var{chardevid},and redirect indev's packet to filter.if it has the vnet_hdr_support flag,
4574 filter-redirector will redirect packet with vnet_hdr_len.
4575 Create a filter-redirector we need to differ outdev id from indev id, id can not
4576 be the same. we can just use indev or outdev, but at least one of indev or outdev
4577 need to be specified.
4579 @item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},queue=@var{all|rx|tx},[vnet_hdr_support]
4581 Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
4582 secondary from primary to keep secondary tcp connection,and rewrite
4583 tcp packet to primary from secondary make tcp packet can be handled by
4584 client.if it has the vnet_hdr_support flag, we can parse packet with vnet header.
4588 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4589 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4590 -object filter-rewriter,id=rew0,netdev=hn0,queue=all
4592 @item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}]
4594 Dump the network traffic on netdev @var{dev} to the file specified by
4595 @var{filename}. At most @var{len} bytes (64k by default) per packet are stored.
4596 The file format is libpcap, so it can be analyzed with tools such as tcpdump
4599 @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}]
4601 Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with
4602 secondary packet. If the packets are same, we will output primary
4603 packet to outdev@var{chardevid}, else we will notify colo-frame
4604 do checkpoint and send primary packet to outdev@var{chardevid}.
4605 In order to improve efficiency, we need to put the task of comparison
4606 in another thread. If it has the vnet_hdr_support flag, colo compare
4607 will send/recv packet with vnet_hdr_len.
4608 If you want to use Xen COLO, will need the notify_dev to notify Xen
4609 colo-frame to do checkpoint.
4611 we must use it with the help of filter-mirror and filter-redirector.
4618 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4619 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4620 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4621 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4622 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4623 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4624 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4625 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4626 -object iothread,id=iothread1
4627 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4628 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4629 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4630 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
4633 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4634 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4635 -chardev socket,id=red0,host=3.3.3.3,port=9003
4636 -chardev socket,id=red1,host=3.3.3.3,port=9004
4637 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4638 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4644 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4645 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4646 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4647 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4648 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4649 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4650 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4651 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4652 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait
4653 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4654 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4655 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4656 -object iothread,id=iothread1
4657 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
4660 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4661 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4662 -chardev socket,id=red0,host=3.3.3.3,port=9003
4663 -chardev socket,id=red1,host=3.3.3.3,port=9004
4664 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4665 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4669 If you want to know the detail of above command line, you can read
4670 the colo-compare git log.
4672 @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
4674 Creates a cryptodev backend which executes crypto opreation from
4675 the QEMU cipher APIS. The @var{id} parameter is
4676 a unique ID that will be used to reference this cryptodev backend from
4677 the @option{virtio-crypto} device. The @var{queues} parameter is optional,
4678 which specify the queue number of cryptodev backend, the default of
4683 # @value{qemu_system} \
4685 -object cryptodev-backend-builtin,id=cryptodev0 \
4686 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4690 @item -object cryptodev-vhost-user,id=@var{id},chardev=@var{chardevid}[,queues=@var{queues}]
4692 Creates a vhost-user cryptodev backend, backed by a chardev @var{chardevid}.
4693 The @var{id} parameter is a unique ID that will be used to reference this
4694 cryptodev backend from the @option{virtio-crypto} device.
4695 The chardev should be a unix domain socket backed one. The vhost-user uses
4696 a specifically defined protocol to pass vhost ioctl replacement messages
4697 to an application on the other end of the socket.
4698 The @var{queues} parameter is optional, which specify the queue number
4699 of cryptodev backend for multiqueue vhost-user, the default of @var{queues} is 1.
4703 # @value{qemu_system} \
4705 -chardev socket,id=chardev0,path=/path/to/socket \
4706 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \
4707 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4711 @item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4712 @item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4714 Defines a secret to store a password, encryption key, or some other sensitive
4715 data. The sensitive data can either be passed directly via the @var{data}
4716 parameter, or indirectly via the @var{file} parameter. Using the @var{data}
4717 parameter is insecure unless the sensitive data is encrypted.
4719 The sensitive data can be provided in raw format (the default), or base64.
4720 When encoded as JSON, the raw format only supports valid UTF-8 characters,
4721 so base64 is recommended for sending binary data. QEMU will convert from
4722 which ever format is provided to the format it needs internally. eg, an
4723 RBD password can be provided in raw format, even though it will be base64
4724 encoded when passed onto the RBD sever.
4726 For added protection, it is possible to encrypt the data associated with
4727 a secret using the AES-256-CBC cipher. Use of encryption is indicated
4728 by providing the @var{keyid} and @var{iv} parameters. The @var{keyid}
4729 parameter provides the ID of a previously defined secret that contains
4730 the AES-256 decryption key. This key should be 32-bytes long and be
4731 base64 encoded. The @var{iv} parameter provides the random initialization
4732 vector used for encryption of this particular secret and should be a
4733 base64 encrypted string of the 16-byte IV.
4735 The simplest (insecure) usage is to provide the secret inline
4739 # @value{qemu_system} -object secret,id=sec0,data=letmein,format=raw
4743 The simplest secure usage is to provide the secret via a file
4745 # printf "letmein
" > mypasswd.txt
4746 # @value{qemu_system} -object secret,id=sec0,file=mypasswd.txt,format=raw
4748 For greater security, AES-256-CBC should be used. To illustrate usage,
4749 consider the openssl command line tool which can encrypt the data. Note
4750 that when encrypting, the plaintext must be padded to the cipher block
4751 size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm.
4753 First a master key needs to be created in base64 encoding:
4756 # openssl rand -base64 32 > key.b64
4757 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X
"')
4760 Each secret to be encrypted needs to have a random initialization vector
4761 generated. These do not need to be kept secret
4764 # openssl rand -base64 16 > iv.b64
4765 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X
"')
4768 The secret to be defined can now be encrypted, in this case we're
4769 telling openssl to base64 encode the result, but it could be left
4770 as raw bytes if desired.
4773 # SECRET=$(printf "letmein
" |
4774 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
4777 When launching QEMU, create a master secret pointing to @code{key.b64}
4778 and specify that to be used to decrypt the user password. Pass the
4779 contents of @code{iv.b64} to the second secret
4782 # @value{qemu_system} \
4783 -object secret,id=secmaster0,format=base64,file=key.b64 \
4784 -object secret,id=sec0,keyid=secmaster0,format=base64,\
4785 data=$SECRET,iv=$(<iv.b64)
4788 @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}]
4790 Create a Secure Encrypted Virtualization (SEV) guest object, which can be used
4791 to provide the guest memory encryption support on AMD processors.
4793 When memory encryption is enabled, one of the physical address bit (aka the
4794 C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos}
4795 is used to provide the C-bit position. The C-bit position is Host family dependent
4796 hence user must provide this value. On EPYC, the value should be 47.
4798 When memory encryption is enabled, we loose certain bits in physical address space.
4799 The @option{reduced-phys-bits} is used to provide the number of bits we loose in
4800 physical address space. Similar to C-bit, the value is Host family dependent.
4801 On EPYC, the value should be 5.
4803 The @option{sev-device} provides the device file to use for communicating with
4804 the SEV firmware running inside AMD Secure Processor. The default device is
4805 '/dev/sev'. If hardware supports memory encryption then /dev/sev devices are
4806 created by CCP driver.
4808 The @option{policy} provides the guest policy to be enforced by the SEV firmware
4809 and restrict what configuration and operational commands can be performed on this
4810 guest by the hypervisor. The policy should be provided by the guest owner and is
4811 bound to the guest and cannot be changed throughout the lifetime of the guest.
4814 If guest @option{policy} allows sharing the key with another SEV guest then
4815 @option{handle} can be use to provide handle of the guest from which to share
4818 The @option{dh-cert-file} and @option{session-file} provides the guest owner's
4819 Public Diffie-Hillman key defined in SEV spec. The PDH and session parameters
4820 are used for establishing a cryptographic session with the guest owner to
4821 negotiate keys used for attestation. The file must be encoded in base64.
4823 e.g to launch a SEV guest
4825 # @value{qemu_system_x86} \
4827 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \
4828 -machine ...,memory-encryption=sev0
4834 @item -object authz-simple,id=@var{id},identity=@var{string}
4836 Create an authorization object that will control access to network services.
4838 The @option{identity} parameter is identifies the user and its format
4839 depends on the network service that authorization object is associated
4840 with. For authorizing based on TLS x509 certificates, the identity must
4841 be the x509 distinguished name. Note that care must be taken to escape
4842 any commas in the distinguished name.
4844 An example authorization object to validate a x509 distinguished name
4847 # @value{qemu_system} \
4849 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \
4853 Note the use of quotes due to the x509 distinguished name containing
4854 whitespace, and escaping of ','.
4856 @item -object authz-listfile,id=@var{id},filename=@var{path},refresh=@var{yes|no}
4858 Create an authorization object that will control access to network services.
4860 The @option{filename} parameter is the fully qualified path to a file
4861 containing the access control list rules in JSON format.
4863 An example set of rules that match against SASL usernames might look
4869 @{ "match
": "fred
", "policy
": "allow
", "format
": "exact
" @},
4870 @{ "match
": "bob
", "policy
": "allow
", "format
": "exact
" @},
4871 @{ "match
": "danb
", "policy
": "deny
", "format
": "glob
" @},
4872 @{ "match
": "dan
*", "policy
": "allow
", "format
": "exact
" @},
4878 When checking access the object will iterate over all the rules and
4879 the first rule to match will have its @option{policy} value returned
4880 as the result. If no rules match, then the default @option{policy}
4883 The rules can either be an exact string match, or they can use the
4884 simple UNIX glob pattern matching to allow wildcards to be used.
4886 If @option{refresh} is set to true the file will be monitored
4887 and automatically reloaded whenever its content changes.
4889 As with the @code{authz-simple} object, the format of the identity
4890 strings being matched depends on the network service, but is usually
4891 a TLS x509 distinguished name, or a SASL username.
4893 An example authorization object to validate a SASL username
4896 # @value{qemu_system} \
4898 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=yes
4902 @item -object authz-pam,id=@var{id},service=@var{string}
4904 Create an authorization object that will control access to network services.
4906 The @option{service} parameter provides the name of a PAM service to use
4907 for authorization. It requires that a file @code{/etc/pam.d/@var{service}}
4908 exist to provide the configuration for the @code{account} subsystem.
4910 An example authorization object to validate a TLS x509 distinguished
4911 name would look like:
4914 # @value{qemu_system} \
4916 -object authz-pam,id=auth0,service=qemu-vnc
4920 There would then be a corresponding config file for PAM at
4921 @code{/etc/pam.d/qemu-vnc} that contains:
4924 account requisite pam_listfile.so item=user sense=allow \
4925 file=/etc/qemu/vnc.allow
4928 Finally the @code{/etc/qemu/vnc.allow} file would contain
4929 the list of x509 distingished names that are permitted
4933 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
4936 @item -object iothread,id=@var{id},poll-max-ns=@var{poll-max-ns},poll-grow=@var{poll-grow},poll-shrink=@var{poll-shrink}
4938 Creates a dedicated event loop thread that devices can be assigned to. This is
4939 known as an IOThread. By default device emulation happens in vCPU threads or
4940 the main event loop thread. This can become a scalability bottleneck.
4941 IOThreads allow device emulation and I/O to run on other host CPUs.
4943 The @option{id} parameter is a unique ID that will be used to reference this
4944 IOThread from @option{-device ...,iothread=@var{id}}. Multiple devices can be
4945 assigned to an IOThread. Note that not all devices support an
4946 @option{iothread} parameter.
4948 The @code{query-iothreads} QMP command lists IOThreads and reports their thread
4949 IDs so that the user can configure host CPU pinning/affinity.
4951 IOThreads use an adaptive polling algorithm to reduce event loop latency.
4952 Instead of entering a blocking system call to monitor file descriptors and then
4953 pay the cost of being woken up when an event occurs, the polling algorithm
4954 spins waiting for events for a short time. The algorithm's default parameters
4955 are suitable for many cases but can be adjusted based on knowledge of the
4956 workload and/or host device latency.
4958 The @option{poll-max-ns} parameter is the maximum number of nanoseconds to busy
4959 wait for events. Polling can be disabled by setting this value to 0.
4961 The @option{poll-grow} parameter is the multiplier used to increase the polling
4962 time when the algorithm detects it is missing events due to not polling long
4965 The @option{poll-shrink} parameter is the divisor used to decrease the polling
4966 time when the algorithm detects it is spending too long polling without
4967 encountering events.
4969 The polling parameters can be modified at run-time using the @code{qom-set} command (where @code{iothread1} is the IOThread's @code{id}):
4972 (qemu) qom-set /objects/iothread1 poll-max-ns 100000
4980 HXCOMM This is the last statement. Insert new options before this line!