/
qemu-options.hx
3118 lines (2646 loc) · 113 KB
/
qemu-options.hx
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
HXCOMM Use DEFHEADING() to define headings in both help text and texi
HXCOMM Text between STEXI and ETEXI are copied to texi version and
HXCOMM discarded from C version
HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to
HXCOMM construct option structures, enums and help message for specified
HXCOMM architectures.
HXCOMM HXCOMM can be used for comments, discarded from both texi and C
DEFHEADING(Standard options:)
STEXI
@table @option
ETEXI
DEF("help", 0, QEMU_OPTION_h,
"-h or -help display this help and exit\n", QEMU_ARCH_ALL)
STEXI
@item -h
@findex -h
Display help and exit
ETEXI
DEF("version", 0, QEMU_OPTION_version,
"-version display version information and exit\n", QEMU_ARCH_ALL)
STEXI
@item -version
@findex -version
Display version information and exit
ETEXI
DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
"-machine [type=]name[,prop[=value][,...]]\n"
" selects emulated machine ('-machine help' for list)\n"
" property accel=accel1[:accel2[:...]] selects accelerator\n"
" supported accelerators are kvm, xen, tcg (default: tcg)\n"
" kernel_irqchip=on|off controls accelerated irqchip support\n"
" kvm_shadow_mem=size of KVM shadow MMU\n"
" dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
" mem-merge=on|off controls memory merge support (default: on)\n",
QEMU_ARCH_ALL)
STEXI
@item -machine [type=]@var{name}[,prop=@var{value}[,...]]
@findex -machine
Select the emulated machine by @var{name}. Use @code{-machine help} to list
available machines. Supported machine properties are:
@table @option
@item accel=@var{accels1}[:@var{accels2}[:...]]
This is used to enable an accelerator. Depending on the target architecture,
kvm, xen, or tcg can be available. By default, tcg is used. If there is more
than one accelerator specified, the next one is used if the previous one fails
to initialize.
@item kernel_irqchip=on|off
Enables in-kernel irqchip support for the chosen accelerator when available.
@item kvm_shadow_mem=size
Defines the size of the KVM shadow MMU.
@item dump-guest-core=on|off
Include guest memory in a core dump. The default is on.
@item mem-merge=on|off
Enables or disables memory merge support. This feature, when supported by
the host, de-duplicates identical memory pages among VMs instances
(enabled by default).
@end table
ETEXI
HXCOMM Deprecated by -machine
DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL)
DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
"-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL)
STEXI
@item -cpu @var{model}
@findex -cpu
Select CPU model (@code{-cpu help} for list and additional feature selection)
ETEXI
DEF("smp", HAS_ARG, QEMU_OPTION_smp,
"-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]\n"
" set the number of CPUs to 'n' [default=1]\n"
" maxcpus= maximum number of total cpus, including\n"
" offline CPUs for hotplug, etc\n"
" cores= number of CPU cores on one socket\n"
" threads= number of threads on one CPU core\n"
" sockets= number of discrete sockets in the system\n",
QEMU_ARCH_ALL)
STEXI
@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
@findex -smp
Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs
to 4.
For the PC target, the number of @var{cores} per socket, the number
of @var{threads} per cores and the total number of @var{sockets} can be
specified. Missing values will be computed. If any on the three values is
given, the total number of CPUs @var{n} can be omitted. @var{maxcpus}
specifies the maximum number of hotpluggable CPUs.
ETEXI
DEF("numa", HAS_ARG, QEMU_OPTION_numa,
"-numa node[,mem=size][,cpus=cpu[-cpu]][,nodeid=node]\n", QEMU_ARCH_ALL)
STEXI
@item -numa @var{opts}
@findex -numa
Simulate a multi node NUMA system. If mem and cpus are omitted, resources
are split equally.
ETEXI
DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
"-add-fd fd=fd,set=set[,opaque=opaque]\n"
" Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
STEXI
@item -add-fd fd=@var{fd},set=@var{set}[,opaque=@var{opaque}]
@findex -add-fd
Add a file descriptor to an fd set. Valid options are:
@table @option
@item fd=@var{fd}
This option defines the file descriptor of which a duplicate is added to fd set.
The file descriptor cannot be stdin, stdout, or stderr.
@item set=@var{set}
This option defines the ID of the fd set to add the file descriptor to.
@item opaque=@var{opaque}
This option defines a free-form string that can be used to describe @var{fd}.
@end table
You can open an image using pre-opened file descriptors from an fd set:
@example
qemu-system-i386
-add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
-add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
-drive file=/dev/fdset/2,index=0,media=disk
@end example
ETEXI
DEF("set", HAS_ARG, QEMU_OPTION_set,
"-set group.id.arg=value\n"
" set <arg> parameter for item <id> of type <group>\n"
" i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
STEXI
@item -set @var{group}.@var{id}.@var{arg}=@var{value}
@findex -set
Set parameter @var{arg} for item @var{id} of type @var{group}\n"
ETEXI
DEF("global", HAS_ARG, QEMU_OPTION_global,
"-global driver.prop=value\n"
" set a global default for a driver property\n",
QEMU_ARCH_ALL)
STEXI
@item -global @var{driver}.@var{prop}=@var{value}
@findex -global
Set default value of @var{driver}'s property @var{prop} to @var{value}, e.g.:
@example
qemu-system-i386 -global ide-drive.physical_block_size=4096 -drive file=file,if=ide,index=0,media=disk
@end example
In particular, you can use this to set driver properties for devices which are
created automatically by the machine model. To create a device which is not
created automatically and set properties on it, use -@option{device}.
ETEXI
DEF("boot", HAS_ARG, QEMU_OPTION_boot,
"-boot [order=drives][,once=drives][,menu=on|off]\n"
" [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
" 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
" 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
" 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
" 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
QEMU_ARCH_ALL)
STEXI
@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]
@findex -boot
Specify boot order @var{drives} as a string of drive letters. Valid
drive letters depend on the target achitecture. The x86 PC uses: a, b
(floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot
from network adapter 1-4), hard disk boot is the default. To apply a
particular boot order only on the first startup, specify it via
@option{once}.
Interactive boot menus/prompts can be enabled via @option{menu=on} as far
as firmware/BIOS supports them. The default is non-interactive boot.
A splash picture could be passed to bios, enabling user to show it as logo,
when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS
supports them. Currently Seabios for X86 system support it.
limitation: The splash file could be a jpeg file or a BMP file in 24 BPP
format(true color). The resolution should be supported by the SVGA mode, so
the recommended is 320x240, 640x480, 800x640.
A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms
when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
system support it.
Do strict boot via @option{strict=on} as far as firmware/BIOS
supports it. This only effects when boot priority is changed by
bootindex options. The default is non-strict boot.
@example
# try to boot from network first, then from hard disk
qemu-system-i386 -boot order=nc
# boot from CD-ROM first, switch back to default order after reboot
qemu-system-i386 -boot once=d
# boot with a splash picture for 5 seconds.
qemu-system-i386 -boot menu=on,splash=/root/boot.bmp,splash-time=5000
@end example
Note: The legacy format '-boot @var{drives}' is still supported but its
use is discouraged as it may be removed from future versions.
ETEXI
DEF("m", HAS_ARG, QEMU_OPTION_m,
"-m megs set virtual RAM size to megs MB [default="
stringify(DEFAULT_RAM_SIZE) "]\n", QEMU_ARCH_ALL)
STEXI
@item -m @var{megs}
@findex -m
Set virtual RAM size to @var{megs} megabytes. Default is 128 MiB. Optionally,
a suffix of ``M'' or ``G'' can be used to signify a value in megabytes or
gigabytes respectively.
ETEXI
DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
"-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
STEXI
@item -mem-path @var{path}
@findex -mem-path
Allocate guest RAM from a temporarily created file in @var{path}.
ETEXI
#ifdef MAP_POPULATE
DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
"-mem-prealloc preallocate guest memory (use with -mem-path)\n",
QEMU_ARCH_ALL)
STEXI
@item -mem-prealloc
@findex -mem-prealloc
Preallocate memory when using -mem-path.
ETEXI
#endif
DEF("k", HAS_ARG, QEMU_OPTION_k,
"-k language use keyboard layout (for example 'fr' for French)\n",
QEMU_ARCH_ALL)
STEXI
@item -k @var{language}
@findex -k
Use keyboard layout @var{language} (for example @code{fr} for
French). This option is only needed where it is not easy to get raw PC
keycodes (e.g. on Macs, with some X11 servers or with a VNC
display). You don't normally need to use it on PC/Linux or PC/Windows
hosts.
The available layouts are:
@example
ar de-ch es fo fr-ca hu ja mk no pt-br sv
da en-gb et fr fr-ch is lt nl pl ru th
de en-us fi fr-be hr it lv nl-be pt sl tr
@end example
The default is @code{en-us}.
ETEXI
DEF("audio-help", 0, QEMU_OPTION_audio_help,
"-audio-help print list of audio drivers and their options\n",
QEMU_ARCH_ALL)
STEXI
@item -audio-help
@findex -audio-help
Will show the audio subsystem help: list of drivers, tunable
parameters.
ETEXI
DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw,
"-soundhw c1,... enable audio support\n"
" and only specified sound cards (comma separated list)\n"
" use '-soundhw help' to get the list of supported cards\n"
" use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL)
STEXI
@item -soundhw @var{card1}[,@var{card2},...] or -soundhw all
@findex -soundhw
Enable audio and selected sound hardware. Use 'help' to print all
available sound hardware.
@example
qemu-system-i386 -soundhw sb16,adlib disk.img
qemu-system-i386 -soundhw es1370 disk.img
qemu-system-i386 -soundhw ac97 disk.img
qemu-system-i386 -soundhw hda disk.img
qemu-system-i386 -soundhw all disk.img
qemu-system-i386 -soundhw help
@end example
Note that Linux's i810_audio OSS kernel (for AC97) module might
require manually specifying clocking.
@example
modprobe i810_audio clocking=48000
@end example
ETEXI
DEF("balloon", HAS_ARG, QEMU_OPTION_balloon,
"-balloon none disable balloon device\n"
"-balloon virtio[,addr=str]\n"
" enable virtio balloon device (default)\n", QEMU_ARCH_ALL)
STEXI
@item -balloon none
@findex -balloon
Disable balloon device.
@item -balloon virtio[,addr=@var{addr}]
Enable virtio balloon device (default), optionally with PCI address
@var{addr}.
ETEXI
DEF("device", HAS_ARG, QEMU_OPTION_device,
"-device driver[,prop[=value][,...]]\n"
" add device (based on driver)\n"
" prop=value,... sets driver properties\n"
" use '-device help' to print all possible drivers\n"
" use '-device driver,help' to print all possible properties\n",
QEMU_ARCH_ALL)
STEXI
@item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
@findex -device
Add device @var{driver}. @var{prop}=@var{value} sets driver
properties. Valid properties depend on the driver. To get help on
possible drivers and properties, use @code{-device help} and
@code{-device @var{driver},help}.
ETEXI
DEF("name", HAS_ARG, QEMU_OPTION_name,
"-name string1[,process=string2]\n"
" set the name of the guest\n"
" string1 sets the window title and string2 the process name (on Linux)\n",
QEMU_ARCH_ALL)
STEXI
@item -name @var{name}
@findex -name
Sets the @var{name} of the guest.
This name will be displayed in the SDL window caption.
The @var{name} will also be used for the VNC server.
Also optionally set the top visible process name in Linux.
ETEXI
DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
"-uuid %08x-%04x-%04x-%04x-%012x\n"
" specify machine UUID\n", QEMU_ARCH_ALL)
STEXI
@item -uuid @var{uuid}
@findex -uuid
Set system UUID.
ETEXI
STEXI
@end table
ETEXI
DEFHEADING()
DEFHEADING(Block device options:)
STEXI
@table @option
ETEXI
DEF("fda", HAS_ARG, QEMU_OPTION_fda,
"-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
STEXI
@item -fda @var{file}
@item -fdb @var{file}
@findex -fda
@findex -fdb
Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}). You can
use the host floppy by using @file{/dev/fd0} as filename (@pxref{host_drives}).
ETEXI
DEF("hda", HAS_ARG, QEMU_OPTION_hda,
"-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
"-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
STEXI
@item -hda @var{file}
@item -hdb @var{file}
@item -hdc @var{file}
@item -hdd @var{file}
@findex -hda
@findex -hdb
@findex -hdc
@findex -hdd
Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).
ETEXI
DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
"-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
QEMU_ARCH_ALL)
STEXI
@item -cdrom @var{file}
@findex -cdrom
Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
@option{-cdrom} at the same time). You can use the host CD-ROM by
using @file{/dev/cdrom} as filename (@pxref{host_drives}).
ETEXI
DEF("drive", HAS_ARG, QEMU_OPTION_drive,
"-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
" [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
" [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
" [,serial=s][,addr=A][,id=name][,aio=threads|native]\n"
" [,readonly=on|off][,copy-on-read=on|off]\n"
" [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]][[,iops=i]|[[,iops_rd=r][,iops_wr=w]]\n"
" use 'file' as a drive image\n", QEMU_ARCH_ALL)
STEXI
@item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
@findex -drive
Define a new drive. Valid options are:
@table @option
@item file=@var{file}
This option defines which disk image (@pxref{disk_images}) to use with
this drive. If the filename contains comma, you must double it
(for instance, "file=my,,file" to use file "my,file").
Special files such as iSCSI devices can be specified using protocol
specific URLs. See the section for "Device URL Syntax" for more information.
@item if=@var{interface}
This option defines on which type on interface the drive is connected.
Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio.
@item bus=@var{bus},unit=@var{unit}
These options define where is connected the drive by defining the bus number and
the unit id.
@item index=@var{index}
This option defines where is connected the drive by using an index in the list
of available connectors of a given interface type.
@item media=@var{media}
This option defines the type of the media: disk or cdrom.
@item cyls=@var{c},heads=@var{h},secs=@var{s}[,trans=@var{t}]
These options have the same definition as they have in @option{-hdachs}.
@item snapshot=@var{snapshot}
@var{snapshot} is "on" or "off" and allows to enable snapshot for given drive (see @option{-snapshot}).
@item cache=@var{cache}
@var{cache} is "none", "writeback", "unsafe", "directsync" or "writethrough" and controls how the host cache is used to access block data.
@item aio=@var{aio}
@var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
@item discard=@var{discard}
@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap}) requests are ignored or passed to the filesystem. Some machine types may not support discard requests.
@item format=@var{format}
Specify which disk @var{format} will be used rather than detecting
the format. Can be used to specifiy format=raw to avoid interpreting
an untrusted format header.
@item serial=@var{serial}
This option specifies the serial number to assign to the device.
@item addr=@var{addr}
Specify the controller's PCI address (if=virtio only).
@item werror=@var{action},rerror=@var{action}
Specify which @var{action} to take on write and read errors. Valid actions are:
"ignore" (ignore the error and try to continue), "stop" (pause QEMU),
"report" (report the error to the guest), "enospc" (pause QEMU only if the
host disk is full; report the error to the guest otherwise).
The default setting is @option{werror=enospc} and @option{rerror=report}.
@item readonly
Open drive @option{file} as read-only. Guest write attempts will fail.
@item copy-on-read=@var{copy-on-read}
@var{copy-on-read} is "on" or "off" and enables whether to copy read backing
file sectors into the image file.
@end table
By default, the @option{cache=writeback} mode is used. It will report data
writes as completed as soon as the data is present in the host page cache.
This is safe as long as your guest OS makes sure to correctly flush disk caches
where needed. If your guest OS does not handle volatile disk write caches
correctly and your host crashes or loses power, then the guest may experience
data corruption.
For such guests, you should consider using @option{cache=writethrough}. This
means that the host page cache will be used to read and write data, but write
notification will be sent to the guest only after QEMU has made sure to flush
each write to the disk. Be aware that this has a major impact on performance.
The host page cache can be avoided entirely with @option{cache=none}. This will
attempt to do disk IO directly to the guest's memory. QEMU may still perform
an internal copy of the data. Note that this is considered a writeback mode and
the guest OS must handle the disk write cache correctly in order to avoid data
corruption on host crashes.
The host page cache can be avoided while only sending write notifications to
the guest when the data has been flushed to the disk using
@option{cache=directsync}.
In case you don't care about data integrity over host failures, use
@option{cache=unsafe}. This option tells QEMU that it never needs to write any
data to the disk but can instead keep things in cache. If anything goes wrong,
like your host losing power, the disk storage getting disconnected accidentally,
etc. your image will most probably be rendered unusable. When using
the @option{-snapshot} option, unsafe caching is always used.
Copy-on-read avoids accessing the same backing file sectors repeatedly and is
useful when the backing file is over a slow network. By default copy-on-read
is off.
Instead of @option{-cdrom} you can use:
@example
qemu-system-i386 -drive file=file,index=2,media=cdrom
@end example
Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
use:
@example
qemu-system-i386 -drive file=file,index=0,media=disk
qemu-system-i386 -drive file=file,index=1,media=disk
qemu-system-i386 -drive file=file,index=2,media=disk
qemu-system-i386 -drive file=file,index=3,media=disk
@end example
You can open an image using pre-opened file descriptors from an fd set:
@example
qemu-system-i386
-add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
-add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
-drive file=/dev/fdset/2,index=0,media=disk
@end example
You can connect a CDROM to the slave of ide0:
@example
qemu-system-i386 -drive file=file,if=ide,index=1,media=cdrom
@end example
If you don't specify the "file=" argument, you define an empty drive:
@example
qemu-system-i386 -drive if=ide,index=1,media=cdrom
@end example
You can connect a SCSI disk with unit ID 6 on the bus #0:
@example
qemu-system-i386 -drive file=file,if=scsi,bus=0,unit=6
@end example
Instead of @option{-fda}, @option{-fdb}, you can use:
@example
qemu-system-i386 -drive file=file,index=0,if=floppy
qemu-system-i386 -drive file=file,index=1,if=floppy
@end example
By default, @var{interface} is "ide" and @var{index} is automatically
incremented:
@example
qemu-system-i386 -drive file=a -drive file=b"
@end example
is interpreted like:
@example
qemu-system-i386 -hda a -hdb b
@end example
ETEXI
DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
"-mtdblock file use 'file' as on-board Flash memory image\n",
QEMU_ARCH_ALL)
STEXI
@item -mtdblock @var{file}
@findex -mtdblock
Use @var{file} as on-board Flash memory image.
ETEXI
DEF("sd", HAS_ARG, QEMU_OPTION_sd,
"-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
STEXI
@item -sd @var{file}
@findex -sd
Use @var{file} as SecureDigital card image.
ETEXI
DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
"-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
STEXI
@item -pflash @var{file}
@findex -pflash
Use @var{file} as a parallel flash image.
ETEXI
DEF("snapshot", 0, QEMU_OPTION_snapshot,
"-snapshot write to temporary files instead of disk image files\n",
QEMU_ARCH_ALL)
STEXI
@item -snapshot
@findex -snapshot
Write to temporary files instead of disk image files. In this case,
the raw disk image you use is not written back. You can however force
the write back by pressing @key{C-a s} (@pxref{disk_images}).
ETEXI
DEF("hdachs", HAS_ARG, QEMU_OPTION_hdachs, \
"-hdachs c,h,s[,t]\n" \
" force hard disk 0 physical geometry and the optional BIOS\n" \
" translation (t=none or lba) (usually QEMU can guess them)\n",
QEMU_ARCH_ALL)
STEXI
@item -hdachs @var{c},@var{h},@var{s},[,@var{t}]
@findex -hdachs
Force hard disk 0 physical geometry (1 <= @var{c} <= 16383, 1 <=
@var{h} <= 16, 1 <= @var{s} <= 63) and optionally force the BIOS
translation mode (@var{t}=none, lba or auto). Usually QEMU can guess
all those parameters. This option is useful for old MS-DOS disk
images.
ETEXI
DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
"-fsdev fsdriver,id=id[,path=path,][security_model={mapped-xattr|mapped-file|passthrough|none}]\n"
" [,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd]\n",
QEMU_ARCH_ALL)
STEXI
@item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}]
@findex -fsdev
Define a new file system device. Valid options are:
@table @option
@item @var{fsdriver}
This option specifies the fs driver backend to use.
Currently "local", "handle" and "proxy" file system drivers are supported.
@item id=@var{id}
Specifies identifier for this device
@item path=@var{path}
Specifies the export path for the file system device. Files under
this path will be available to the 9p client on the guest.
@item security_model=@var{security_model}
Specifies the security model to be used for this export path.
Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
In "passthrough" security model, files are stored using the same
credentials as they are created on the guest. This requires QEMU
to run as root. In "mapped-xattr" security model, some of the file
attributes like uid, gid, mode bits and link target are stored as
file attributes. For "mapped-file" these attributes are stored in the
hidden .virtfs_metadata directory. Directories exported by this security model cannot
interact with other unix tools. "none" security model is same as
passthrough except the sever won't report failures if it fails to
set file attributes like ownership. Security model is mandatory
only for local fsdriver. Other fsdrivers (like handle, proxy) don't take
security model as a parameter.
@item writeout=@var{writeout}
This is an optional argument. The only supported value is "immediate".
This means that host page cache will be used to read and write data but
write notification will be sent to the guest only when the data has been
reported as written by the storage subsystem.
@item readonly
Enables exporting 9p share as a readonly mount for guests. By default
read-write access is given.
@item socket=@var{socket}
Enables proxy filesystem driver to use passed socket file for communicating
with virtfs-proxy-helper
@item sock_fd=@var{sock_fd}
Enables proxy filesystem driver to use passed socket descriptor for
communicating with virtfs-proxy-helper. Usually a helper like libvirt
will create socketpair and pass one of the fds as sock_fd
@end table
-fsdev option is used along with -device driver "virtio-9p-pci".
@item -device virtio-9p-pci,fsdev=@var{id},mount_tag=@var{mount_tag}
Options for virtio-9p-pci driver are:
@table @option
@item fsdev=@var{id}
Specifies the id value specified along with -fsdev option
@item mount_tag=@var{mount_tag}
Specifies the tag name to be used by the guest to mount this export point
@end table
ETEXI
DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
"-virtfs local,path=path,mount_tag=tag,security_model=[mapped-xattr|mapped-file|passthrough|none]\n"
" [,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd]\n",
QEMU_ARCH_ALL)
STEXI
@item -virtfs @var{fsdriver}[,path=@var{path}],mount_tag=@var{mount_tag}[,security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}]
@findex -virtfs
The general form of a Virtual File system pass-through options are:
@table @option
@item @var{fsdriver}
This option specifies the fs driver backend to use.
Currently "local", "handle" and "proxy" file system drivers are supported.
@item id=@var{id}
Specifies identifier for this device
@item path=@var{path}
Specifies the export path for the file system device. Files under
this path will be available to the 9p client on the guest.
@item security_model=@var{security_model}
Specifies the security model to be used for this export path.
Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
In "passthrough" security model, files are stored using the same
credentials as they are created on the guest. This requires QEMU
to run as root. In "mapped-xattr" security model, some of the file
attributes like uid, gid, mode bits and link target are stored as
file attributes. For "mapped-file" these attributes are stored in the
hidden .virtfs_metadata directory. Directories exported by this security model cannot
interact with other unix tools. "none" security model is same as
passthrough except the sever won't report failures if it fails to
set file attributes like ownership. Security model is mandatory only
for local fsdriver. Other fsdrivers (like handle, proxy) don't take security
model as a parameter.
@item writeout=@var{writeout}
This is an optional argument. The only supported value is "immediate".
This means that host page cache will be used to read and write data but
write notification will be sent to the guest only when the data has been
reported as written by the storage subsystem.
@item readonly
Enables exporting 9p share as a readonly mount for guests. By default
read-write access is given.
@item socket=@var{socket}
Enables proxy filesystem driver to use passed socket file for
communicating with virtfs-proxy-helper. Usually a helper like libvirt
will create socketpair and pass one of the fds as sock_fd
@item sock_fd
Enables proxy filesystem driver to use passed 'sock_fd' as the socket
descriptor for interfacing with virtfs-proxy-helper
@end table
ETEXI
DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
"-virtfs_synth Create synthetic file system image\n",
QEMU_ARCH_ALL)
STEXI
@item -virtfs_synth
@findex -virtfs_synth
Create synthetic file system image
ETEXI
STEXI
@end table
ETEXI
DEFHEADING()
DEFHEADING(USB options:)
STEXI
@table @option
ETEXI
DEF("usb", 0, QEMU_OPTION_usb,
"-usb enable the USB driver (will be the default soon)\n",
QEMU_ARCH_ALL)
STEXI
@item -usb
@findex -usb
Enable the USB driver (will be the default soon)
ETEXI
DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
"-usbdevice name add the host or guest USB device 'name'\n",
QEMU_ARCH_ALL)
STEXI
@item -usbdevice @var{devname}
@findex -usbdevice
Add the USB device @var{devname}. @xref{usb_devices}.
@table @option
@item mouse
Virtual Mouse. This will override the PS/2 mouse emulation when activated.
@item tablet
Pointer device that uses absolute coordinates (like a touchscreen). This
means QEMU is able to report the mouse position without having to grab the
mouse. Also overrides the PS/2 mouse emulation when activated.
@item disk:[format=@var{format}]:@var{file}
Mass storage device based on file. The optional @var{format} argument
will be used rather than detecting the format. Can be used to specifiy
@code{format=raw} to avoid interpreting an untrusted format header.
@item host:@var{bus}.@var{addr}
Pass through the host device identified by @var{bus}.@var{addr} (Linux only).
@item host:@var{vendor_id}:@var{product_id}
Pass through the host device identified by @var{vendor_id}:@var{product_id}
(Linux only).
@item serial:[vendorid=@var{vendor_id}][,productid=@var{product_id}]:@var{dev}
Serial converter to host character device @var{dev}, see @code{-serial} for the
available devices.
@item braille
Braille device. This will use BrlAPI to display the braille output on a real
or fake device.
@item net:@var{options}
Network adapter that supports CDC ethernet and RNDIS protocols.
@end table
ETEXI
STEXI
@end table
ETEXI
DEFHEADING()
DEFHEADING(Display options:)
STEXI
@table @option
ETEXI
DEF("display", HAS_ARG, QEMU_OPTION_display,
"-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
" [,window_close=on|off]|curses|none|\n"
" vnc=<display>[,<optargs>]\n"
" select display type\n", QEMU_ARCH_ALL)
STEXI
@item -display @var{type}
@findex -display
Select type of display to use. This option is a replacement for the
old style -sdl/-curses/... options. Valid values for @var{type} are
@table @option
@item sdl
Display video output via SDL (usually in a separate graphics
window; see the SDL documentation for other possibilities).
@item curses
Display video output via curses. For graphics device models which
support a text mode, QEMU can display this output using a
curses/ncurses interface. Nothing is displayed when the graphics
device is in graphical mode or if the graphics device does not support
a text mode. Generally only the VGA device models support text mode.
@item none
Do not display video output. The guest will still see an emulated
graphics card, but its output will not be displayed to the QEMU
user. This option differs from the -nographic option in that it
only affects what is done with video output; -nographic also changes
the destination of the serial and parallel port data.
@item vnc
Start a VNC server on display <arg>
@end table
ETEXI
DEF("nographic", 0, QEMU_OPTION_nographic,
"-nographic disable graphical output and redirect serial I/Os to console\n",
QEMU_ARCH_ALL)
STEXI
@item -nographic
@findex -nographic
Normally, QEMU uses SDL to display the VGA output. With this option,
you can totally disable graphical output so that QEMU is a simple
command line application. The emulated serial port is redirected on
the console and muxed with the monitor (unless redirected elsewhere
explicitly). Therefore, you can still use QEMU to debug a Linux kernel
with a serial console. Use @key{C-a h} for help on switching between
the console and monitor.
ETEXI
DEF("curses", 0, QEMU_OPTION_curses,
"-curses use a curses/ncurses interface instead of SDL\n",
QEMU_ARCH_ALL)
STEXI
@item -curses
@findex -curses
Normally, QEMU uses SDL to display the VGA output. With this option,
QEMU can display the VGA output when in text mode using a
curses/ncurses interface. Nothing is displayed in graphical mode.
ETEXI
DEF("no-frame", 0, QEMU_OPTION_no_frame,
"-no-frame open SDL window without a frame and window decorations\n",
QEMU_ARCH_ALL)
STEXI
@item -no-frame
@findex -no-frame
Do not use decorations for SDL windows and start them using the whole
available screen space. This makes the using QEMU in a dedicated desktop
workspace more convenient.
ETEXI
DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
"-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
QEMU_ARCH_ALL)
STEXI
@item -alt-grab
@findex -alt-grab
Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also
affects the special keys (for fullscreen, monitor-mode switching, etc).
ETEXI
DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
"-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
QEMU_ARCH_ALL)
STEXI
@item -ctrl-grab
@findex -ctrl-grab
Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also
affects the special keys (for fullscreen, monitor-mode switching, etc).
ETEXI
DEF("no-quit", 0, QEMU_OPTION_no_quit,
"-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL)
STEXI
@item -no-quit
@findex -no-quit
Disable SDL window close capability.
ETEXI
DEF("sdl", 0, QEMU_OPTION_sdl,
"-sdl enable SDL\n", QEMU_ARCH_ALL)
STEXI
@item -sdl
@findex -sdl
Enable SDL.
ETEXI
DEF("spice", HAS_ARG, QEMU_OPTION_spice,
"-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
" [,x509-key-file=<file>][,x509-key-password=<file>]\n"
" [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
" [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6]\n"
" [,tls-ciphers=<list>]\n"
" [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
" [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
" [,sasl][,password=<secret>][,disable-ticketing]\n"
" [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
" [,jpeg-wan-compression=[auto|never|always]]\n"
" [,zlib-glz-wan-compression=[auto|never|always]]\n"
" [,streaming-video=[off|all|filter]][,disable-copy-paste]\n"
" [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n"
" [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
" enable spice\n"
" at least one of {port, tls-port} is mandatory\n",
QEMU_ARCH_ALL)
STEXI
@item -spice @var{option}[,@var{option}[,...]]
@findex -spice
Enable the spice remote desktop protocol. Valid options are
@table @option
@item port=<nr>
Set the TCP port spice is listening on for plaintext channels.
@item addr=<addr>
Set the IP address spice is listening on. Default is any address.
@item ipv4
@item ipv6
Force using the specified IP version.
@item password=<secret>
Set the password you need to authenticate.
@item sasl
Require that the client use SASL to authenticate with the spice.
The exact choice of authentication method used is controlled from the
system / user's SASL configuration file for the 'qemu' service. This
is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
unprivileged user, an environment variable SASL_CONF_PATH can be used
to make it search alternate locations for the service config.
While some SASL auth methods can also provide data encryption (eg GSSAPI),
it is recommended that SASL always be combined with the 'tls' and
'x509' settings to enable use of SSL and server certificates. This
ensures a data encryption preventing compromise of authentication
credentials.
@item disable-ticketing
Allow client connects without authentication.
@item disable-copy-paste
Disable copy paste between the client and the guest.
@item disable-agent-file-xfer
Disable spice-vdagent based file-xfer between the client and the guest.
@item tls-port=<nr>
Set the TCP port spice is listening on for encrypted channels.
@item x509-dir=<dir>
Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
@item x509-key-file=<file>
@item x509-key-password=<file>
@item x509-cert-file=<file>
@item x509-cacert-file=<file>
@item x509-dh-key-file=<file>
The x509 file names can also be configured individually.
@item tls-ciphers=<list>
Specify which ciphers to use.
@item tls-channel=[main|display|cursor|inputs|record|playback]
@item plaintext-channel=[main|display|cursor|inputs|record|playback]
Force specific channel to be used with or without TLS encryption. The
options can be specified multiple times to configure multiple
channels. The special name "default" can be used to set the default
mode. For channels which are not explicitly forced into one mode the
spice client is allowed to pick tls/plaintext as he pleases.
@item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
Configure image compression (lossless).
Default is auto_glz.
@item jpeg-wan-compression=[auto|never|always]
@item zlib-glz-wan-compression=[auto|never|always]
Configure wan image compression (lossy for slow links).
Default is auto.