1 \input texinfo @c -*- texinfo -*-
3 @setfilename qemu-doc.info
7 @documentencoding UTF-8
9 @settitle QEMU version @value{VERSION} User Documentation
16 * QEMU: (qemu-doc). The QEMU Emulator User Documentation.
23 @center @titlefont{QEMU version @value{VERSION}}
25 @center @titlefont{User Documentation}
36 * QEMU PC System emulator::
37 * QEMU System emulator for non PC targets::
39 * QEMU User space emulator::
40 * Implementation notes::
52 * intro_features:: Features
58 QEMU is a FAST! processor emulator using dynamic translation to
59 achieve good emulation speed.
61 @cindex operating modes
62 QEMU has two operating modes:
65 @cindex system emulation
66 @item Full system emulation. In this mode, QEMU emulates a full system (for
67 example a PC), including one or several processors and various
68 peripherals. It can be used to launch different Operating Systems
69 without rebooting the PC or to debug system code.
71 @cindex user mode emulation
72 @item User mode emulation. In this mode, QEMU can launch
73 processes compiled for one CPU on another CPU. It can be used to
74 launch the Wine Windows API emulator (@url{http://www.winehq.org}) or
75 to ease cross-compilation and cross-debugging.
79 QEMU has the following features:
82 @item QEMU can run without a host kernel driver and yet gives acceptable
83 performance. It uses dynamic translation to native code for reasonable speed,
84 with support for self-modifying code and precise exceptions.
86 @item It is portable to several operating systems (GNU/Linux, *BSD, Mac OS X,
87 Windows) and architectures.
89 @item It performs accurate software emulation of the FPU.
92 QEMU user mode emulation has the following features:
94 @item Generic Linux system call converter, including most ioctls.
96 @item clone() emulation using native CPU clone() to use Linux scheduler for threads.
98 @item Accurate signal handling by remapping host signals to target signals.
101 QEMU full system emulation has the following features:
104 QEMU uses a full software MMU for maximum portability.
107 QEMU can optionally use an in-kernel accelerator, like kvm. The accelerators
108 execute most of the guest code natively, while
109 continuing to emulate the rest of the machine.
112 Various hardware devices can be emulated and in some cases, host
113 devices (e.g. serial and parallel ports, USB, drives) can be used
114 transparently by the guest Operating System. Host device passthrough
115 can be used for talking to external physical peripherals (e.g. a
116 webcam, modem or tape drive).
119 Symmetric multiprocessing (SMP) support. Currently, an in-kernel
120 accelerator is required to use more than one host CPU for emulation.
125 @node QEMU PC System emulator
126 @chapter QEMU PC System emulator
127 @cindex system emulation (PC)
130 * pcsys_introduction:: Introduction
131 * pcsys_quickstart:: Quick Start
132 * sec_invocation:: Invocation
133 * pcsys_keys:: Keys in the graphical frontends
134 * mux_keys:: Keys in the character backend multiplexer
135 * pcsys_monitor:: QEMU Monitor
136 * disk_images:: Disk Images
137 * pcsys_network:: Network emulation
138 * pcsys_other_devs:: Other Devices
139 * direct_linux_boot:: Direct Linux Boot
140 * pcsys_usb:: USB emulation
141 * vnc_security:: VNC security
142 * gdb_usage:: GDB usage
143 * pcsys_os_specific:: Target OS specific information
146 @node pcsys_introduction
147 @section Introduction
149 @c man begin DESCRIPTION
151 The QEMU PC System emulator simulates the
152 following peripherals:
156 i440FX host PCI bridge and PIIX3 PCI to ISA bridge
158 Cirrus CLGD 5446 PCI VGA card or dummy VGA card with Bochs VESA
159 extensions (hardware level, including all non standard modes).
161 PS/2 mouse and keyboard
163 2 PCI IDE interfaces with hard disk and CD-ROM support
167 PCI and ISA network adapters
171 IPMI BMC, either and internal or external one
173 Creative SoundBlaster 16 sound card
175 ENSONIQ AudioPCI ES1370 sound card
177 Intel 82801AA AC97 Audio compatible sound card
179 Intel HD Audio Controller and HDA codec
181 Adlib (OPL2) - Yamaha YM3812 compatible chip
183 Gravis Ultrasound GF1 sound card
185 CS4231A compatible sound card
187 PCI UHCI, OHCI, EHCI or XHCI USB controller and a virtual USB-1.1 hub.
190 SMP is supported with up to 255 CPUs.
192 QEMU uses the PC BIOS from the Seabios project and the Plex86/Bochs LGPL
195 QEMU uses YM3812 emulation by Tatsuyuki Satoh.
197 QEMU uses GUS emulation (GUSEMU32 @url{http://www.deinmeister.de/gusemu/})
198 by Tibor "TS" Schütz.
200 Note that, by default, GUS shares IRQ(7) with parallel ports and so
201 QEMU must be told to not have parallel ports to have working GUS.
204 qemu-system-i386 dos.img -soundhw gus -parallel none
209 qemu-system-i386 dos.img -device gus,irq=5
212 Or some other unclaimed IRQ.
214 CS4231A is the chip used in Windows Sound System and GUSMAX products
218 @node pcsys_quickstart
222 Download and uncompress the linux image (@file{linux.img}) and type:
225 qemu-system-i386 linux.img
228 Linux should boot and give you a prompt.
234 @c man begin SYNOPSIS
235 @command{qemu-system-i386} [@var{options}] [@var{disk_image}]
240 @var{disk_image} is a raw hard disk image for IDE hard disk 0. Some
241 targets do not need a disk image.
243 @include qemu-options.texi
248 @section Keys in the graphical frontends
252 During the graphical emulation, you can use special key combinations to change
253 modes. The default key mappings are shown below, but if you use @code{-alt-grab}
254 then the modifier is Ctrl-Alt-Shift (instead of Ctrl-Alt) and if you use
255 @code{-ctrl-grab} then the modifier is the right Ctrl key (instead of Ctrl-Alt):
272 Restore the screen's un-scaled dimensions
276 Switch to virtual console 'n'. Standard console mappings are:
279 Target system display
288 Toggle mouse and keyboard grab.
294 @kindex Ctrl-PageDown
295 In the virtual consoles, you can use @key{Ctrl-Up}, @key{Ctrl-Down},
296 @key{Ctrl-PageUp} and @key{Ctrl-PageDown} to move in the back log.
301 @section Keys in the character backend multiplexer
305 During emulation, if you are using a character backend multiplexer
306 (which is the default if you are using @option{-nographic}) then
307 several commands are available via an escape sequence. These
308 key sequences all start with an escape character, which is @key{Ctrl-a}
309 by default, but can be changed with @option{-echr}. The list below assumes
310 you're using the default.
321 Save disk data back to file (if -snapshot)
324 Toggle console timestamps
327 Send break (magic sysrq in Linux)
330 Rotate between the frontends connected to the multiplexer (usually
331 this switches between the monitor and the console)
333 @kindex Ctrl-a Ctrl-a
334 Send the escape character to the frontend
341 The HTML documentation of QEMU for more precise information and Linux
342 user mode emulator invocation.
352 @section QEMU Monitor
355 The QEMU monitor is used to give complex commands to the QEMU
356 emulator. You can use it to:
361 Remove or insert removable media images
362 (such as CD-ROM or floppies).
365 Freeze/unfreeze the Virtual Machine (VM) and save or restore its state
368 @item Inspect the VM state without an external debugger.
374 The following commands are available:
376 @include qemu-monitor.texi
378 @include qemu-monitor-info.texi
380 @subsection Integer expressions
382 The monitor understands integers expressions for every integer
383 argument. You can use register names to get the value of specifics
384 CPU registers by prefixing them with @emph{$}.
389 Since version 0.6.1, QEMU supports many disk image formats, including
390 growable disk images (their size increase as non empty sectors are
391 written), compressed and encrypted disk images. Version 0.8.3 added
392 the new qcow2 disk image format which is essential to support VM
396 * disk_images_quickstart:: Quick start for disk image creation
397 * disk_images_snapshot_mode:: Snapshot mode
398 * vm_snapshots:: VM snapshots
399 * qemu_img_invocation:: qemu-img Invocation
400 * qemu_nbd_invocation:: qemu-nbd Invocation
401 * disk_images_formats:: Disk image file formats
402 * host_drives:: Using host drives
403 * disk_images_fat_images:: Virtual FAT disk images
404 * disk_images_nbd:: NBD access
405 * disk_images_sheepdog:: Sheepdog disk images
406 * disk_images_iscsi:: iSCSI LUNs
407 * disk_images_gluster:: GlusterFS disk images
408 * disk_images_ssh:: Secure Shell (ssh) disk images
411 @node disk_images_quickstart
412 @subsection Quick start for disk image creation
414 You can create a disk image with the command:
416 qemu-img create myimage.img mysize
418 where @var{myimage.img} is the disk image filename and @var{mysize} is its
419 size in kilobytes. You can add an @code{M} suffix to give the size in
420 megabytes and a @code{G} suffix for gigabytes.
422 See @ref{qemu_img_invocation} for more information.
424 @node disk_images_snapshot_mode
425 @subsection Snapshot mode
427 If you use the option @option{-snapshot}, all disk images are
428 considered as read only. When sectors in written, they are written in
429 a temporary file created in @file{/tmp}. You can however force the
430 write back to the raw disk images by using the @code{commit} monitor
431 command (or @key{C-a s} in the serial console).
434 @subsection VM snapshots
436 VM snapshots are snapshots of the complete virtual machine including
437 CPU state, RAM, device state and the content of all the writable
438 disks. In order to use VM snapshots, you must have at least one non
439 removable and writable block device using the @code{qcow2} disk image
440 format. Normally this device is the first virtual hard drive.
442 Use the monitor command @code{savevm} to create a new VM snapshot or
443 replace an existing one. A human readable name can be assigned to each
444 snapshot in addition to its numerical ID.
446 Use @code{loadvm} to restore a VM snapshot and @code{delvm} to remove
447 a VM snapshot. @code{info snapshots} lists the available snapshots
448 with their associated information:
451 (qemu) info snapshots
452 Snapshot devices: hda
453 Snapshot list (from hda):
454 ID TAG VM SIZE DATE VM CLOCK
455 1 start 41M 2006-08-06 12:38:02 00:00:14.954
456 2 40M 2006-08-06 12:43:29 00:00:18.633
457 3 msys 40M 2006-08-06 12:44:04 00:00:23.514
460 A VM snapshot is made of a VM state info (its size is shown in
461 @code{info snapshots}) and a snapshot of every writable disk image.
462 The VM state info is stored in the first @code{qcow2} non removable
463 and writable block device. The disk image snapshots are stored in
464 every disk image. The size of a snapshot in a disk image is difficult
465 to evaluate and is not shown by @code{info snapshots} because the
466 associated disk sectors are shared among all the snapshots to save
467 disk space (otherwise each snapshot would need a full copy of all the
470 When using the (unrelated) @code{-snapshot} option
471 (@ref{disk_images_snapshot_mode}), you can always make VM snapshots,
472 but they are deleted as soon as you exit QEMU.
474 VM snapshots currently have the following known limitations:
477 They cannot cope with removable devices if they are removed or
478 inserted after a snapshot is done.
480 A few device drivers still have incomplete snapshot support so their
481 state is not saved or restored properly (in particular USB).
484 @node qemu_img_invocation
485 @subsection @code{qemu-img} Invocation
487 @include qemu-img.texi
489 @node qemu_nbd_invocation
490 @subsection @code{qemu-nbd} Invocation
492 @include qemu-nbd.texi
494 @node disk_images_formats
495 @subsection Disk image file formats
497 QEMU supports many image file formats that can be used with VMs as well as with
498 any of the tools (like @code{qemu-img}). This includes the preferred formats
499 raw and qcow2 as well as formats that are supported for compatibility with
500 older QEMU versions or other hypervisors.
502 Depending on the image format, different options can be passed to
503 @code{qemu-img create} and @code{qemu-img convert} using the @code{-o} option.
504 This section describes each format and the options that are supported for it.
509 Raw disk image format. This format has the advantage of
510 being simple and easily exportable to all other emulators. If your
511 file system supports @emph{holes} (for example in ext2 or ext3 on
512 Linux or NTFS on Windows), then only the written sectors will reserve
513 space. Use @code{qemu-img info} to know the real size used by the
514 image or @code{ls -ls} on Unix/Linux.
519 Preallocation mode (allowed values: @code{off}, @code{falloc}, @code{full}).
520 @code{falloc} mode preallocates space for image by calling posix_fallocate().
521 @code{full} mode preallocates space for image by writing zeros to underlying
526 QEMU image format, the most versatile format. Use it to have smaller
527 images (useful if your filesystem does not supports holes, for example
528 on Windows), zlib based compression and support of multiple VM
534 Determines the qcow2 version to use. @code{compat=0.10} uses the
535 traditional image format that can be read by any QEMU since 0.10.
536 @code{compat=1.1} enables image format extensions that only QEMU 1.1 and
537 newer understand (this is the default). Amongst others, this includes
538 zero clusters, which allow efficient copy-on-read for sparse images.
541 File name of a base image (see @option{create} subcommand)
543 Image format of the base image
545 If this option is set to @code{on}, the image is encrypted with 128-bit AES-CBC.
547 The use of encryption in qcow and qcow2 images is considered to be flawed by
548 modern cryptography standards, suffering from a number of design problems:
551 @item The AES-CBC cipher is used with predictable initialization vectors based
552 on the sector number. This makes it vulnerable to chosen plaintext attacks
553 which can reveal the existence of encrypted data.
554 @item The user passphrase is directly used as the encryption key. A poorly
555 chosen or short passphrase will compromise the security of the encryption.
556 @item In the event of the passphrase being compromised there is no way to
557 change the passphrase to protect data in any qcow images. The files must
558 be cloned, using a different encryption passphrase in the new file. The
559 original file must then be securely erased using a program like shred,
560 though even this is ineffective with many modern storage technologies.
563 Use of qcow / qcow2 encryption with QEMU is deprecated, and support for
564 it will go away in a future release. Users are recommended to use an
565 alternative encryption technology such as the Linux dm-crypt / LUKS
569 Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster
570 sizes can improve the image file size whereas larger cluster sizes generally
571 provide better performance.
574 Preallocation mode (allowed values: @code{off}, @code{metadata}, @code{falloc},
575 @code{full}). An image with preallocated metadata is initially larger but can
576 improve performance when the image needs to grow. @code{falloc} and @code{full}
577 preallocations are like the same options of @code{raw} format, but sets up
581 If this option is set to @code{on}, reference count updates are postponed with
582 the goal of avoiding metadata I/O and improving performance. This is
583 particularly interesting with @option{cache=writethrough} which doesn't batch
584 metadata updates. The tradeoff is that after a host crash, the reference count
585 tables must be rebuilt, i.e. on the next open an (automatic) @code{qemu-img
586 check -r all} is required, which may take some time.
588 This option can only be enabled if @code{compat=1.1} is specified.
591 If this option is set to @code{on}, it will turn off COW of the file. It's only
592 valid on btrfs, no effect on other file systems.
594 Btrfs has low performance when hosting a VM image file, even more when the guest
595 on the VM also using btrfs as file system. Turning off COW is a way to mitigate
596 this bad performance. Generally there are two ways to turn off COW on btrfs:
597 a) Disable it by mounting with nodatacow, then all newly created files will be
598 NOCOW. b) For an empty file, add the NOCOW file attribute. That's what this option
601 Note: this option is only valid to new or empty files. If there is an existing
602 file which is COW and has data blocks already, it couldn't be changed to NOCOW
603 by setting @code{nocow=on}. One can issue @code{lsattr filename} to check if
604 the NOCOW flag is set or not (Capital 'C' is NOCOW flag).
609 Old QEMU image format with support for backing files and compact image files
610 (when your filesystem or transport medium does not support holes).
612 When converting QED images to qcow2, you might want to consider using the
613 @code{lazy_refcounts=on} option to get a more QED-like behaviour.
618 File name of a base image (see @option{create} subcommand).
620 Image file format of backing file (optional). Useful if the format cannot be
621 autodetected because it has no header, like some vhd/vpc files.
623 Changes the cluster size (must be power-of-2 between 4K and 64K). Smaller
624 cluster sizes can improve the image file size whereas larger cluster sizes
625 generally provide better performance.
627 Changes the number of clusters per L1/L2 table (must be power-of-2 between 1
628 and 16). There is normally no need to change this value but this option can be
629 used for performance benchmarking.
633 Old QEMU image format with support for backing files, compact image files,
634 encryption and compression.
639 File name of a base image (see @option{create} subcommand)
641 If this option is set to @code{on}, the image is encrypted.
645 VirtualBox 1.1 compatible image format.
649 If this option is set to @code{on}, the image is created with metadata
654 VMware 3 and 4 compatible image format.
659 File name of a base image (see @option{create} subcommand).
661 Create a VMDK version 6 image (instead of version 4)
663 Specify vmdk virtual hardware version. Compat6 flag cannot be enabled
664 if hwversion is specified.
666 Specifies which VMDK subformat to use. Valid options are
667 @code{monolithicSparse} (default),
668 @code{monolithicFlat},
669 @code{twoGbMaxExtentSparse},
670 @code{twoGbMaxExtentFlat} and
671 @code{streamOptimized}.
675 VirtualPC compatible image format (VHD).
679 Specifies which VHD subformat to use. Valid options are
680 @code{dynamic} (default) and @code{fixed}.
684 Hyper-V compatible image format (VHDX).
688 Specifies which VHDX subformat to use. Valid options are
689 @code{dynamic} (default) and @code{fixed}.
690 @item block_state_zero
691 Force use of payload blocks of type 'ZERO'. Can be set to @code{on} (default)
692 or @code{off}. When set to @code{off}, new blocks will be created as
693 @code{PAYLOAD_BLOCK_NOT_PRESENT}, which means parsers are free to return
694 arbitrary data for those blocks. Do not set to @code{off} when using
695 @code{qemu-img convert} with @code{subformat=dynamic}.
697 Block size; min 1 MB, max 256 MB. 0 means auto-calculate based on image size.
703 @subsubsection Read-only formats
704 More disk image file formats are supported in a read-only mode.
707 Bochs images of @code{growing} type.
709 Linux Compressed Loop image, useful only to reuse directly compressed
710 CD-ROM images present for example in the Knoppix CD-ROMs.
714 Parallels disk image format.
719 @subsection Using host drives
721 In addition to disk image files, QEMU can directly access host
722 devices. We describe here the usage for QEMU version >= 0.8.3.
726 On Linux, you can directly use the host device filename instead of a
727 disk image filename provided you have enough privileges to access
728 it. For example, use @file{/dev/cdrom} to access to the CDROM.
732 You can specify a CDROM device even if no CDROM is loaded. QEMU has
733 specific code to detect CDROM insertion or removal. CDROM ejection by
734 the guest OS is supported. Currently only data CDs are supported.
736 You can specify a floppy device even if no floppy is loaded. Floppy
737 removal is currently not detected accurately (if you change floppy
738 without doing floppy access while the floppy is not loaded, the guest
739 OS will think that the same floppy is loaded).
740 Use of the host's floppy device is deprecated, and support for it will
741 be removed in a future release.
743 Hard disks can be used. Normally you must specify the whole disk
744 (@file{/dev/hdb} instead of @file{/dev/hdb1}) so that the guest OS can
745 see it as a partitioned disk. WARNING: unless you know what you do, it
746 is better to only make READ-ONLY accesses to the hard disk otherwise
747 you may corrupt your host data (use the @option{-snapshot} command
748 line option or modify the device permissions accordingly).
751 @subsubsection Windows
755 The preferred syntax is the drive letter (e.g. @file{d:}). The
756 alternate syntax @file{\\.\d:} is supported. @file{/dev/cdrom} is
757 supported as an alias to the first CDROM drive.
759 Currently there is no specific code to handle removable media, so it
760 is better to use the @code{change} or @code{eject} monitor commands to
761 change or eject media.
763 Hard disks can be used with the syntax: @file{\\.\PhysicalDrive@var{N}}
764 where @var{N} is the drive number (0 is the first hard disk).
765 @file{/dev/hda} is supported as an alias to
766 the first hard disk drive @file{\\.\PhysicalDrive0}.
768 WARNING: unless you know what you do, it is better to only make
769 READ-ONLY accesses to the hard disk otherwise you may corrupt your
770 host data (use the @option{-snapshot} command line so that the
771 modifications are written in a temporary file).
775 @subsubsection Mac OS X
777 @file{/dev/cdrom} is an alias to the first CDROM.
779 Currently there is no specific code to handle removable media, so it
780 is better to use the @code{change} or @code{eject} monitor commands to
781 change or eject media.
783 @node disk_images_fat_images
784 @subsection Virtual FAT disk images
786 QEMU can automatically create a virtual FAT disk image from a
787 directory tree. In order to use it, just type:
790 qemu-system-i386 linux.img -hdb fat:/my_directory
793 Then you access access to all the files in the @file{/my_directory}
794 directory without having to copy them in a disk image or to export
795 them via SAMBA or NFS. The default access is @emph{read-only}.
797 Floppies can be emulated with the @code{:floppy:} option:
800 qemu-system-i386 linux.img -fda fat:floppy:/my_directory
803 A read/write support is available for testing (beta stage) with the
807 qemu-system-i386 linux.img -fda fat:floppy:rw:/my_directory
810 What you should @emph{never} do:
812 @item use non-ASCII filenames ;
813 @item use "-snapshot" together with ":rw:" ;
814 @item expect it to work when loadvm'ing ;
815 @item write to the FAT directory on the host system while accessing it with the guest system.
818 @node disk_images_nbd
819 @subsection NBD access
821 QEMU can access directly to block device exported using the Network Block Device
825 qemu-system-i386 linux.img -hdb nbd://my_nbd_server.mydomain.org:1024/
828 If the NBD server is located on the same host, you can use an unix socket instead
832 qemu-system-i386 linux.img -hdb nbd+unix://?socket=/tmp/my_socket
835 In this case, the block device must be exported using qemu-nbd:
838 qemu-nbd --socket=/tmp/my_socket my_disk.qcow2
841 The use of qemu-nbd allows sharing of a disk between several guests:
843 qemu-nbd --socket=/tmp/my_socket --share=2 my_disk.qcow2
847 and then you can use it with two guests:
849 qemu-system-i386 linux1.img -hdb nbd+unix://?socket=/tmp/my_socket
850 qemu-system-i386 linux2.img -hdb nbd+unix://?socket=/tmp/my_socket
853 If the nbd-server uses named exports (supported since NBD 2.9.18, or with QEMU's
854 own embedded NBD server), you must specify an export name in the URI:
856 qemu-system-i386 -cdrom nbd://localhost/debian-500-ppc-netinst
857 qemu-system-i386 -cdrom nbd://localhost/openSUSE-11.1-ppc-netinst
860 The URI syntax for NBD is supported since QEMU 1.3. An alternative syntax is
861 also available. Here are some example of the older syntax:
863 qemu-system-i386 linux.img -hdb nbd:my_nbd_server.mydomain.org:1024
864 qemu-system-i386 linux2.img -hdb nbd:unix:/tmp/my_socket
865 qemu-system-i386 -cdrom nbd:localhost:10809:exportname=debian-500-ppc-netinst
868 @node disk_images_sheepdog
869 @subsection Sheepdog disk images
871 Sheepdog is a distributed storage system for QEMU. It provides highly
872 available block level storage volumes that can be attached to
873 QEMU-based virtual machines.
875 You can create a Sheepdog disk image with the command:
877 qemu-img create sheepdog:///@var{image} @var{size}
879 where @var{image} is the Sheepdog image name and @var{size} is its
882 To import the existing @var{filename} to Sheepdog, you can use a
885 qemu-img convert @var{filename} sheepdog:///@var{image}
888 You can boot from the Sheepdog disk image with the command:
890 qemu-system-i386 sheepdog:///@var{image}
893 You can also create a snapshot of the Sheepdog image like qcow2.
895 qemu-img snapshot -c @var{tag} sheepdog:///@var{image}
897 where @var{tag} is a tag name of the newly created snapshot.
899 To boot from the Sheepdog snapshot, specify the tag name of the
902 qemu-system-i386 sheepdog:///@var{image}#@var{tag}
905 You can create a cloned image from the existing snapshot.
907 qemu-img create -b sheepdog:///@var{base}#@var{tag} sheepdog:///@var{image}
909 where @var{base} is a image name of the source snapshot and @var{tag}
912 You can use an unix socket instead of an inet socket:
915 qemu-system-i386 sheepdog+unix:///@var{image}?socket=@var{path}
918 If the Sheepdog daemon doesn't run on the local host, you need to
919 specify one of the Sheepdog servers to connect to.
921 qemu-img create sheepdog://@var{hostname}:@var{port}/@var{image} @var{size}
922 qemu-system-i386 sheepdog://@var{hostname}:@var{port}/@var{image}
925 @node disk_images_iscsi
926 @subsection iSCSI LUNs
928 iSCSI is a popular protocol used to access SCSI devices across a computer
931 There are two different ways iSCSI devices can be used by QEMU.
933 The first method is to mount the iSCSI LUN on the host, and make it appear as
934 any other ordinary SCSI device on the host and then to access this device as a
935 /dev/sd device from QEMU. How to do this differs between host OSes.
937 The second method involves using the iSCSI initiator that is built into
938 QEMU. This provides a mechanism that works the same way regardless of which
939 host OS you are running QEMU on. This section will describe this second method
940 of using iSCSI together with QEMU.
942 In QEMU, iSCSI devices are described using special iSCSI URLs
946 iscsi://[<username>[%<password>]@@]<host>[:<port>]/<target-iqn-name>/<lun>
949 Username and password are optional and only used if your target is set up
950 using CHAP authentication for access control.
951 Alternatively the username and password can also be set via environment
952 variables to have these not show up in the process list
955 export LIBISCSI_CHAP_USERNAME=<username>
956 export LIBISCSI_CHAP_PASSWORD=<password>
957 iscsi://<host>/<target-iqn-name>/<lun>
960 Various session related parameters can be set via special options, either
961 in a configuration file provided via '-readconfig' or directly on the
964 If the initiator-name is not specified qemu will use a default name
965 of 'iqn.2008-11.org.linux-kvm[:<name>'] where <name> is the name of the
970 Setting a specific initiator name to use when logging in to the target
971 -iscsi initiator-name=iqn.qemu.test:my-initiator
975 Controlling which type of header digest to negotiate with the target
976 -iscsi header-digest=CRC32C|CRC32C-NONE|NONE-CRC32C|NONE
979 These can also be set via a configuration file
982 user = "CHAP username"
983 password = "CHAP password"
984 initiator-name = "iqn.qemu.test:my-initiator"
985 # header digest is one of CRC32C|CRC32C-NONE|NONE-CRC32C|NONE
986 header-digest = "CRC32C"
990 Setting the target name allows different options for different targets
992 [iscsi "iqn.target.name"]
993 user = "CHAP username"
994 password = "CHAP password"
995 initiator-name = "iqn.qemu.test:my-initiator"
996 # header digest is one of CRC32C|CRC32C-NONE|NONE-CRC32C|NONE
997 header-digest = "CRC32C"
1001 Howto use a configuration file to set iSCSI configuration options:
1003 cat >iscsi.conf <<EOF
1006 password = "my password"
1007 initiator-name = "iqn.qemu.test:my-initiator"
1008 header-digest = "CRC32C"
1011 qemu-system-i386 -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \
1012 -readconfig iscsi.conf
1016 Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
1018 This example shows how to set up an iSCSI target with one CDROM and one DISK
1019 using the Linux STGT software target. This target is available on Red Hat based
1020 systems as the package 'scsi-target-utils'.
1022 tgtd --iscsi portal=127.0.0.1:3260
1023 tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
1024 tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
1025 -b /IMAGES/disk.img --device-type=disk
1026 tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
1027 -b /IMAGES/cd.iso --device-type=cd
1028 tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
1030 qemu-system-i386 -iscsi initiator-name=iqn.qemu.test:my-initiator \
1031 -boot d -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \
1032 -cdrom iscsi://127.0.0.1/iqn.qemu.test/2
1035 @node disk_images_gluster
1036 @subsection GlusterFS disk images
1038 GlusterFS is a user space distributed file system.
1040 You can boot from the GlusterFS disk image with the command:
1043 qemu-system-x86_64 -drive file=gluster[+@var{type}]://[@var{host}[:@var{port}]]/@var{volume}/@var{path}
1044 [?socket=...][,file.debug=9][,file.logfile=...]
1047 qemu-system-x86_64 'json:@{"driver":"qcow2",
1048 "file":@{"driver":"gluster",
1049 "volume":"testvol","path":"a.img","debug":9,"logfile":"...",
1050 "server":[@{"type":"tcp","host":"...","port":"..."@},
1051 @{"type":"unix","socket":"..."@}]@}@}'
1054 @var{gluster} is the protocol.
1056 @var{type} specifies the transport type used to connect to gluster
1057 management daemon (glusterd). Valid transport types are
1058 tcp and unix. In the URI form, if a transport type isn't specified,
1059 then tcp type is assumed.
1061 @var{host} specifies the server where the volume file specification for
1062 the given volume resides. This can be either a hostname or an ipv4 address.
1063 If transport type is unix, then @var{host} field should not be specified.
1064 Instead @var{socket} field needs to be populated with the path to unix domain
1067 @var{port} is the port number on which glusterd is listening. This is optional
1068 and if not specified, it defaults to port 24007. If the transport type is unix,
1069 then @var{port} should not be specified.
1071 @var{volume} is the name of the gluster volume which contains the disk image.
1073 @var{path} is the path to the actual disk image that resides on gluster volume.
1075 @var{debug} is the logging level of the gluster protocol driver. Debug levels
1076 are 0-9, with 9 being the most verbose, and 0 representing no debugging output.
1077 The default level is 4. The current logging levels defined in the gluster source
1078 are 0 - None, 1 - Emergency, 2 - Alert, 3 - Critical, 4 - Error, 5 - Warning,
1079 6 - Notice, 7 - Info, 8 - Debug, 9 - Trace
1081 @var{logfile} is a commandline option to mention log file path which helps in
1082 logging to the specified file and also help in persisting the gfapi logs. The
1088 You can create a GlusterFS disk image with the command:
1090 qemu-img create gluster://@var{host}/@var{volume}/@var{path} @var{size}
1095 qemu-system-x86_64 -drive file=gluster://1.2.3.4/testvol/a.img
1096 qemu-system-x86_64 -drive file=gluster+tcp://1.2.3.4/testvol/a.img
1097 qemu-system-x86_64 -drive file=gluster+tcp://1.2.3.4:24007/testvol/dir/a.img
1098 qemu-system-x86_64 -drive file=gluster+tcp://[1:2:3:4:5:6:7:8]/testvol/dir/a.img
1099 qemu-system-x86_64 -drive file=gluster+tcp://[1:2:3:4:5:6:7:8]:24007/testvol/dir/a.img
1100 qemu-system-x86_64 -drive file=gluster+tcp://server.domain.com:24007/testvol/dir/a.img
1101 qemu-system-x86_64 -drive file=gluster+unix:///testvol/dir/a.img?socket=/tmp/glusterd.socket
1102 qemu-system-x86_64 -drive file=gluster+rdma://1.2.3.4:24007/testvol/a.img
1103 qemu-system-x86_64 -drive file=gluster://1.2.3.4/testvol/a.img,file.debug=9,file.logfile=/var/log/qemu-gluster.log
1104 qemu-system-x86_64 'json:@{"driver":"qcow2",
1105 "file":@{"driver":"gluster",
1106 "volume":"testvol","path":"a.img",
1107 "debug":9,"logfile":"/var/log/qemu-gluster.log",
1108 "server":[@{"type":"tcp","host":"1.2.3.4","port":24007@},
1109 @{"type":"unix","socket":"/var/run/glusterd.socket"@}]@}@}'
1110 qemu-system-x86_64 -drive driver=qcow2,file.driver=gluster,file.volume=testvol,file.path=/path/a.img,
1111 file.debug=9,file.logfile=/var/log/qemu-gluster.log,
1112 file.server.0.type=tcp,file.server.0.host=1.2.3.4,file.server.0.port=24007,
1113 file.server.1.type=unix,file.server.1.socket=/var/run/glusterd.socket
1116 @node disk_images_ssh
1117 @subsection Secure Shell (ssh) disk images
1119 You can access disk images located on a remote ssh server
1120 by using the ssh protocol:
1123 qemu-system-x86_64 -drive file=ssh://[@var{user}@@]@var{server}[:@var{port}]/@var{path}[?host_key_check=@var{host_key_check}]
1126 Alternative syntax using properties:
1129 qemu-system-x86_64 -drive file.driver=ssh[,file.user=@var{user}],file.host=@var{server}[,file.port=@var{port}],file.path=@var{path}[,file.host_key_check=@var{host_key_check}]
1132 @var{ssh} is the protocol.
1134 @var{user} is the remote user. If not specified, then the local
1137 @var{server} specifies the remote ssh server. Any ssh server can be
1138 used, but it must implement the sftp-server protocol. Most Unix/Linux
1139 systems should work without requiring any extra configuration.
1141 @var{port} is the port number on which sshd is listening. By default
1142 the standard ssh port (22) is used.
1144 @var{path} is the path to the disk image.
1146 The optional @var{host_key_check} parameter controls how the remote
1147 host's key is checked. The default is @code{yes} which means to use
1148 the local @file{.ssh/known_hosts} file. Setting this to @code{no}
1149 turns off known-hosts checking. Or you can check that the host key
1150 matches a specific fingerprint:
1151 @code{host_key_check=md5:78:45:8e:14:57:4f:d5:45:83:0a:0e:f3:49:82:c9:c8}
1152 (@code{sha1:} can also be used as a prefix, but note that OpenSSH
1153 tools only use MD5 to print fingerprints).
1155 Currently authentication must be done using ssh-agent. Other
1156 authentication methods may be supported in future.
1158 Note: Many ssh servers do not support an @code{fsync}-style operation.
1159 The ssh driver cannot guarantee that disk flush requests are
1160 obeyed, and this causes a risk of disk corruption if the remote
1161 server or network goes down during writes. The driver will
1162 print a warning when @code{fsync} is not supported:
1164 warning: ssh server @code{ssh.example.com:22} does not support fsync
1166 With sufficiently new versions of libssh2 and OpenSSH, @code{fsync} is
1170 @section Network emulation
1172 QEMU can simulate several network cards (PCI or ISA cards on the PC
1173 target) and can connect them to an arbitrary number of Virtual Local
1174 Area Networks (VLANs). Host TAP devices can be connected to any QEMU
1175 VLAN. VLAN can be connected between separate instances of QEMU to
1176 simulate large networks. For simpler usage, a non privileged user mode
1177 network stack can replace the TAP device to have a basic network
1182 QEMU simulates several VLANs. A VLAN can be symbolised as a virtual
1183 connection between several network devices. These devices can be for
1184 example QEMU virtual Ethernet cards or virtual Host ethernet devices
1187 @subsection Using TAP network interfaces
1189 This is the standard way to connect QEMU to a real network. QEMU adds
1190 a virtual network device on your host (called @code{tapN}), and you
1191 can then configure it as if it was a real ethernet card.
1193 @subsubsection Linux host
1195 As an example, you can download the @file{linux-test-xxx.tar.gz}
1196 archive and copy the script @file{qemu-ifup} in @file{/etc} and
1197 configure properly @code{sudo} so that the command @code{ifconfig}
1198 contained in @file{qemu-ifup} can be executed as root. You must verify
1199 that your host kernel supports the TAP network interfaces: the
1200 device @file{/dev/net/tun} must be present.
1202 See @ref{sec_invocation} to have examples of command lines using the
1203 TAP network interfaces.
1205 @subsubsection Windows host
1207 There is a virtual ethernet driver for Windows 2000/XP systems, called
1208 TAP-Win32. But it is not included in standard QEMU for Windows,
1209 so you will need to get it separately. It is part of OpenVPN package,
1210 so download OpenVPN from : @url{http://openvpn.net/}.
1212 @subsection Using the user mode network stack
1214 By using the option @option{-net user} (default configuration if no
1215 @option{-net} option is specified), QEMU uses a completely user mode
1216 network stack (you don't need root privilege to use the virtual
1217 network). The virtual network configuration is the following:
1221 QEMU VLAN <------> Firewall/DHCP server <-----> Internet
1224 ----> DNS server (10.0.2.3)
1226 ----> SMB server (10.0.2.4)
1229 The QEMU VM behaves as if it was behind a firewall which blocks all
1230 incoming connections. You can use a DHCP client to automatically
1231 configure the network in the QEMU VM. The DHCP server assign addresses
1232 to the hosts starting from 10.0.2.15.
1234 In order to check that the user mode network is working, you can ping
1235 the address 10.0.2.2 and verify that you got an address in the range
1236 10.0.2.x from the QEMU virtual DHCP server.
1238 Note that ICMP traffic in general does not work with user mode networking.
1239 @code{ping}, aka. ICMP echo, to the local router (10.0.2.2) shall work,
1240 however. If you're using QEMU on Linux >= 3.0, it can use unprivileged ICMP
1241 ping sockets to allow @code{ping} to the Internet. The host admin has to set
1242 the ping_group_range in order to grant access to those sockets. To allow ping
1243 for GID 100 (usually users group):
1246 echo 100 100 > /proc/sys/net/ipv4/ping_group_range
1249 When using the built-in TFTP server, the router is also the TFTP
1252 When using the @option{'-netdev user,hostfwd=...'} option, TCP or UDP
1253 connections can be redirected from the host to the guest. It allows for
1254 example to redirect X11, telnet or SSH connections.
1256 @subsection Connecting VLANs between QEMU instances
1258 Using the @option{-net socket} option, it is possible to make VLANs
1259 that span several QEMU instances. See @ref{sec_invocation} to have a
1262 @node pcsys_other_devs
1263 @section Other Devices
1265 @subsection Inter-VM Shared Memory device
1267 On Linux hosts, a shared memory device is available. The basic syntax
1271 qemu-system-x86_64 -device ivshmem-plain,memdev=@var{hostmem}
1274 where @var{hostmem} names a host memory backend. For a POSIX shared
1275 memory backend, use something like
1278 -object memory-backend-file,size=1M,share,mem-path=/dev/shm/ivshmem,id=@var{hostmem}
1281 If desired, interrupts can be sent between guest VMs accessing the same shared
1282 memory region. Interrupt support requires using a shared memory server and
1283 using a chardev socket to connect to it. The code for the shared memory server
1284 is qemu.git/contrib/ivshmem-server. An example syntax when using the shared
1288 # First start the ivshmem server once and for all
1289 ivshmem-server -p @var{pidfile} -S @var{path} -m @var{shm-name} -l @var{shm-size} -n @var{vectors}
1291 # Then start your qemu instances with matching arguments
1292 qemu-system-x86_64 -device ivshmem-doorbell,vectors=@var{vectors},chardev=@var{id}
1293 -chardev socket,path=@var{path},id=@var{id}
1296 When using the server, the guest will be assigned a VM ID (>=0) that allows guests
1297 using the same server to communicate via interrupts. Guests can read their
1298 VM ID from a device register (see ivshmem-spec.txt).
1300 @subsubsection Migration with ivshmem
1302 With device property @option{master=on}, the guest will copy the shared
1303 memory on migration to the destination host. With @option{master=off},
1304 the guest will not be able to migrate with the device attached. In the
1305 latter case, the device should be detached and then reattached after
1306 migration using the PCI hotplug support.
1308 At most one of the devices sharing the same memory can be master. The
1309 master must complete migration before you plug back the other devices.
1311 @subsubsection ivshmem and hugepages
1313 Instead of specifying the <shm size> using POSIX shm, you may specify
1314 a memory backend that has hugepage support:
1317 qemu-system-x86_64 -object memory-backend-file,size=1G,mem-path=/dev/hugepages/my-shmem-file,share,id=mb1
1318 -device ivshmem-plain,memdev=mb1
1321 ivshmem-server also supports hugepages mount points with the
1322 @option{-m} memory path argument.
1324 @node direct_linux_boot
1325 @section Direct Linux Boot
1327 This section explains how to launch a Linux kernel inside QEMU without
1328 having to make a full bootable image. It is very useful for fast Linux
1333 qemu-system-i386 -kernel arch/i386/boot/bzImage -hda root-2.4.20.img -append "root=/dev/hda"
1336 Use @option{-kernel} to provide the Linux kernel image and
1337 @option{-append} to give the kernel command line arguments. The
1338 @option{-initrd} option can be used to provide an INITRD image.
1340 When using the direct Linux boot, a disk image for the first hard disk
1341 @file{hda} is required because its boot sector is used to launch the
1344 If you do not need graphical output, you can disable it and redirect
1345 the virtual serial port and the QEMU monitor to the console with the
1346 @option{-nographic} option. The typical command line is:
1348 qemu-system-i386 -kernel arch/i386/boot/bzImage -hda root-2.4.20.img \
1349 -append "root=/dev/hda console=ttyS0" -nographic
1352 Use @key{Ctrl-a c} to switch between the serial console and the
1353 monitor (@pxref{pcsys_keys}).
1356 @section USB emulation
1358 QEMU can emulate a PCI UHCI, OHCI, EHCI or XHCI USB controller. You can
1359 plug virtual USB devices or real host USB devices (only works with certain
1360 host operating systems). QEMU will automatically create and connect virtual
1361 USB hubs as necessary to connect multiple USB devices.
1365 * host_usb_devices::
1368 @subsection Connecting USB devices
1370 USB devices can be connected with the @option{-device usb-...} command line
1371 option or the @code{device_add} monitor command. Available devices are:
1375 Virtual Mouse. This will override the PS/2 mouse emulation when activated.
1377 Pointer device that uses absolute coordinates (like a touchscreen).
1378 This means QEMU is able to report the mouse position without having
1379 to grab the mouse. Also overrides the PS/2 mouse emulation when activated.
1380 @item usb-storage,drive=@var{drive_id}
1381 Mass storage device backed by @var{drive_id} (@pxref{disk_images})
1383 USB attached SCSI device, see
1384 @url{http://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/usb-storage.txt,usb-storage.txt}
1387 Bulk-only transport storage device, see
1388 @url{http://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/usb-storage.txt,usb-storage.txt}
1389 for details here, too
1390 @item usb-mtp,x-root=@var{dir}
1391 Media transfer protocol device, using @var{dir} as root of the file tree
1392 that is presented to the guest.
1393 @item usb-host,hostbus=@var{bus},hostaddr=@var{addr}
1394 Pass through the host device identified by @var{bus} and @var{addr}
1395 @item usb-host,vendorid=@var{vendor},productid=@var{product}
1396 Pass through the host device identified by @var{vendor} and @var{product} ID
1397 @item usb-wacom-tablet
1398 Virtual Wacom PenPartner tablet. This device is similar to the @code{tablet}
1399 above but it can be used with the tslib library because in addition to touch
1400 coordinates it reports touch pressure.
1402 Standard USB keyboard. Will override the PS/2 keyboard (if present).
1403 @item usb-serial,chardev=@var{id}
1404 Serial converter. This emulates an FTDI FT232BM chip connected to host character
1406 @item usb-braille,chardev=@var{id}
1407 Braille device. This will use BrlAPI to display the braille output on a real
1408 or fake device referenced by @var{id}.
1409 @item usb-net[,netdev=@var{id}]
1410 Network adapter that supports CDC ethernet and RNDIS protocols. @var{id}
1411 specifies a netdev defined with @code{-netdev @dots{},id=@var{id}}.
1412 For instance, user-mode networking can be used with
1414 qemu-system-i386 [...] -netdev user,id=net0 -device usb-net,netdev=net0
1417 Smartcard reader device
1421 Bluetooth dongle for the transport layer of HCI. It is connected to HCI
1422 scatternet 0 by default (corresponds to @code{-bt hci,vlan=0}).
1423 Note that the syntax for the @code{-device usb-bt-dongle} option is not as
1424 useful yet as it was with the legacy @code{-usbdevice} option. So to
1425 configure an USB bluetooth device, you might need to use
1426 "@code{-usbdevice bt}[:@var{hci-type}]" instead. This configures a
1427 bluetooth dongle whose type is specified in the same format as with
1428 the @option{-bt hci} option, @pxref{bt-hcis,,allowed HCI types}. If
1429 no type is given, the HCI logic corresponds to @code{-bt hci,vlan=0}.
1430 This USB device implements the USB Transport Layer of HCI. Example
1433 @command{qemu-system-i386} [...@var{OPTIONS}...] @option{-usbdevice} bt:hci,vlan=3 @option{-bt} device:keyboard,vlan=3
1437 @node host_usb_devices
1438 @subsection Using host USB devices on a Linux host
1440 WARNING: this is an experimental feature. QEMU will slow down when
1441 using it. USB devices requiring real time streaming (i.e. USB Video
1442 Cameras) are not supported yet.
1445 @item If you use an early Linux 2.4 kernel, verify that no Linux driver
1446 is actually using the USB device. A simple way to do that is simply to
1447 disable the corresponding kernel module by renaming it from @file{mydriver.o}
1448 to @file{mydriver.o.disabled}.
1450 @item Verify that @file{/proc/bus/usb} is working (most Linux distributions should enable it by default). You should see something like that:
1456 @item Since only root can access to the USB devices directly, you can either launch QEMU as root or change the permissions of the USB devices you want to use. For testing, the following suffices:
1458 chown -R myuid /proc/bus/usb
1461 @item Launch QEMU and do in the monitor:
1464 Device 1.2, speed 480 Mb/s
1465 Class 00: USB device 1234:5678, USB DISK
1467 You should see the list of the devices you can use (Never try to use
1468 hubs, it won't work).
1470 @item Add the device in QEMU by using:
1472 device_add usb-host,vendorid=0x1234,productid=0x5678
1475 Normally the guest OS should report that a new USB device is plugged.
1476 You can use the option @option{-device usb-host,...} to do the same.
1478 @item Now you can try to use the host USB device in QEMU.
1482 When relaunching QEMU, you may have to unplug and plug again the USB
1483 device to make it work again (this is a bug).
1486 @section VNC security
1488 The VNC server capability provides access to the graphical console
1489 of the guest VM across the network. This has a number of security
1490 considerations depending on the deployment scenarios.
1494 * vnc_sec_password::
1495 * vnc_sec_certificate::
1496 * vnc_sec_certificate_verify::
1497 * vnc_sec_certificate_pw::
1499 * vnc_sec_certificate_sasl::
1500 * vnc_generate_cert::
1504 @subsection Without passwords
1506 The simplest VNC server setup does not include any form of authentication.
1507 For this setup it is recommended to restrict it to listen on a UNIX domain
1508 socket only. For example
1511 qemu-system-i386 [...OPTIONS...] -vnc unix:/home/joebloggs/.qemu-myvm-vnc
1514 This ensures that only users on local box with read/write access to that
1515 path can access the VNC server. To securely access the VNC server from a
1516 remote machine, a combination of netcat+ssh can be used to provide a secure
1519 @node vnc_sec_password
1520 @subsection With passwords
1522 The VNC protocol has limited support for password based authentication. Since
1523 the protocol limits passwords to 8 characters it should not be considered
1524 to provide high security. The password can be fairly easily brute-forced by
1525 a client making repeat connections. For this reason, a VNC server using password
1526 authentication should be restricted to only listen on the loopback interface
1527 or UNIX domain sockets. Password authentication is not supported when operating
1528 in FIPS 140-2 compliance mode as it requires the use of the DES cipher. Password
1529 authentication is requested with the @code{password} option, and then once QEMU
1530 is running the password is set with the monitor. Until the monitor is used to
1531 set the password all clients will be rejected.
1534 qemu-system-i386 [...OPTIONS...] -vnc :1,password -monitor stdio
1535 (qemu) change vnc password
1540 @node vnc_sec_certificate
1541 @subsection With x509 certificates
1543 The QEMU VNC server also implements the VeNCrypt extension allowing use of
1544 TLS for encryption of the session, and x509 certificates for authentication.
1545 The use of x509 certificates is strongly recommended, because TLS on its
1546 own is susceptible to man-in-the-middle attacks. Basic x509 certificate
1547 support provides a secure session, but no authentication. This allows any
1548 client to connect, and provides an encrypted session.
1551 qemu-system-i386 [...OPTIONS...] -vnc :1,tls,x509=/etc/pki/qemu -monitor stdio
1554 In the above example @code{/etc/pki/qemu} should contain at least three files,
1555 @code{ca-cert.pem}, @code{server-cert.pem} and @code{server-key.pem}. Unprivileged
1556 users will want to use a private directory, for example @code{$HOME/.pki/qemu}.
1557 NB the @code{server-key.pem} file should be protected with file mode 0600 to
1558 only be readable by the user owning it.
1560 @node vnc_sec_certificate_verify
1561 @subsection With x509 certificates and client verification
1563 Certificates can also provide a means to authenticate the client connecting.
1564 The server will request that the client provide a certificate, which it will
1565 then validate against the CA certificate. This is a good choice if deploying
1566 in an environment with a private internal certificate authority.
1569 qemu-system-i386 [...OPTIONS...] -vnc :1,tls,x509verify=/etc/pki/qemu -monitor stdio
1573 @node vnc_sec_certificate_pw
1574 @subsection With x509 certificates, client verification and passwords
1576 Finally, the previous method can be combined with VNC password authentication
1577 to provide two layers of authentication for clients.
1580 qemu-system-i386 [...OPTIONS...] -vnc :1,password,tls,x509verify=/etc/pki/qemu -monitor stdio
1581 (qemu) change vnc password
1588 @subsection With SASL authentication
1590 The SASL authentication method is a VNC extension, that provides an
1591 easily extendable, pluggable authentication method. This allows for
1592 integration with a wide range of authentication mechanisms, such as
1593 PAM, GSSAPI/Kerberos, LDAP, SQL databases, one-time keys and more.
1594 The strength of the authentication depends on the exact mechanism
1595 configured. If the chosen mechanism also provides a SSF layer, then
1596 it will encrypt the datastream as well.
1598 Refer to the later docs on how to choose the exact SASL mechanism
1599 used for authentication, but assuming use of one supporting SSF,
1600 then QEMU can be launched with:
1603 qemu-system-i386 [...OPTIONS...] -vnc :1,sasl -monitor stdio
1606 @node vnc_sec_certificate_sasl
1607 @subsection With x509 certificates and SASL authentication
1609 If the desired SASL authentication mechanism does not supported
1610 SSF layers, then it is strongly advised to run it in combination
1611 with TLS and x509 certificates. This provides securely encrypted
1612 data stream, avoiding risk of compromising of the security
1613 credentials. This can be enabled, by combining the 'sasl' option
1614 with the aforementioned TLS + x509 options:
1617 qemu-system-i386 [...OPTIONS...] -vnc :1,tls,x509,sasl -monitor stdio
1621 @node vnc_generate_cert
1622 @subsection Generating certificates for VNC
1624 The GNU TLS packages provides a command called @code{certtool} which can
1625 be used to generate certificates and keys in PEM format. At a minimum it
1626 is necessary to setup a certificate authority, and issue certificates to
1627 each server. If using certificates for authentication, then each client
1628 will also need to be issued a certificate. The recommendation is for the
1629 server to keep its certificates in either @code{/etc/pki/qemu} or for
1630 unprivileged users in @code{$HOME/.pki/qemu}.
1634 * vnc_generate_server::
1635 * vnc_generate_client::
1637 @node vnc_generate_ca
1638 @subsubsection Setup the Certificate Authority
1640 This step only needs to be performed once per organization / organizational
1641 unit. First the CA needs a private key. This key must be kept VERY secret
1642 and secure. If this key is compromised the entire trust chain of the certificates
1643 issued with it is lost.
1646 # certtool --generate-privkey > ca-key.pem
1649 A CA needs to have a public certificate. For simplicity it can be a self-signed
1650 certificate, or one issue by a commercial certificate issuing authority. To
1651 generate a self-signed certificate requires one core piece of information, the
1652 name of the organization.
1655 # cat > ca.info <<EOF
1656 cn = Name of your organization
1660 # certtool --generate-self-signed \
1661 --load-privkey ca-key.pem
1662 --template ca.info \
1663 --outfile ca-cert.pem
1666 The @code{ca-cert.pem} file should be copied to all servers and clients wishing to utilize
1667 TLS support in the VNC server. The @code{ca-key.pem} must not be disclosed/copied at all.
1669 @node vnc_generate_server
1670 @subsubsection Issuing server certificates
1672 Each server (or host) needs to be issued with a key and certificate. When connecting
1673 the certificate is sent to the client which validates it against the CA certificate.
1674 The core piece of information for a server certificate is the hostname. This should
1675 be the fully qualified hostname that the client will connect with, since the client
1676 will typically also verify the hostname in the certificate. On the host holding the
1677 secure CA private key:
1680 # cat > server.info <<EOF
1681 organization = Name of your organization
1682 cn = server.foo.example.com
1687 # certtool --generate-privkey > server-key.pem
1688 # certtool --generate-certificate \
1689 --load-ca-certificate ca-cert.pem \
1690 --load-ca-privkey ca-key.pem \
1691 --load-privkey server-key.pem \
1692 --template server.info \
1693 --outfile server-cert.pem
1696 The @code{server-key.pem} and @code{server-cert.pem} files should now be securely copied
1697 to the server for which they were generated. The @code{server-key.pem} is security
1698 sensitive and should be kept protected with file mode 0600 to prevent disclosure.
1700 @node vnc_generate_client
1701 @subsubsection Issuing client certificates
1703 If the QEMU VNC server is to use the @code{x509verify} option to validate client
1704 certificates as its authentication mechanism, each client also needs to be issued
1705 a certificate. The client certificate contains enough metadata to uniquely identify
1706 the client, typically organization, state, city, building, etc. On the host holding
1707 the secure CA private key:
1710 # cat > client.info <<EOF
1714 organization = Name of your organization
1715 cn = client.foo.example.com
1720 # certtool --generate-privkey > client-key.pem
1721 # certtool --generate-certificate \
1722 --load-ca-certificate ca-cert.pem \
1723 --load-ca-privkey ca-key.pem \
1724 --load-privkey client-key.pem \
1725 --template client.info \
1726 --outfile client-cert.pem
1729 The @code{client-key.pem} and @code{client-cert.pem} files should now be securely
1730 copied to the client for which they were generated.
1733 @node vnc_setup_sasl
1735 @subsection Configuring SASL mechanisms
1737 The following documentation assumes use of the Cyrus SASL implementation on a
1738 Linux host, but the principals should apply to any other SASL impl. When SASL
1739 is enabled, the mechanism configuration will be loaded from system default
1740 SASL service config /etc/sasl2/qemu.conf. If running QEMU as an
1741 unprivileged user, an environment variable SASL_CONF_PATH can be used
1742 to make it search alternate locations for the service config.
1744 If the TLS option is enabled for VNC, then it will provide session encryption,
1745 otherwise the SASL mechanism will have to provide encryption. In the latter
1746 case the list of possible plugins that can be used is drastically reduced. In
1747 fact only the GSSAPI SASL mechanism provides an acceptable level of security
1748 by modern standards. Previous versions of QEMU referred to the DIGEST-MD5
1749 mechanism, however, it has multiple serious flaws described in detail in
1750 RFC 6331 and thus should never be used any more. The SCRAM-SHA-1 mechanism
1751 provides a simple username/password auth facility similar to DIGEST-MD5, but
1752 does not support session encryption, so can only be used in combination with
1755 When not using TLS the recommended configuration is
1759 keytab: /etc/qemu/krb5.tab
1762 This says to use the 'GSSAPI' mechanism with the Kerberos v5 protocol, with
1763 the server principal stored in /etc/qemu/krb5.tab. For this to work the
1764 administrator of your KDC must generate a Kerberos principal for the server,
1765 with a name of 'qemu/somehost.example.com@@EXAMPLE.COM' replacing
1766 'somehost.example.com' with the fully qualified host name of the machine
1767 running QEMU, and 'EXAMPLE.COM' with the Kerberos Realm.
1769 When using TLS, if username+password authentication is desired, then a
1770 reasonable configuration is
1773 mech_list: scram-sha-1
1774 sasldb_path: /etc/qemu/passwd.db
1777 The saslpasswd2 program can be used to populate the passwd.db file with
1780 Other SASL configurations will be left as an exercise for the reader. Note that
1781 all mechanisms except GSSAPI, should be combined with use of TLS to ensure a
1782 secure data channel.
1787 QEMU has a primitive support to work with gdb, so that you can do
1788 'Ctrl-C' while the virtual machine is running and inspect its state.
1790 In order to use gdb, launch QEMU with the '-s' option. It will wait for a
1793 qemu-system-i386 -s -kernel arch/i386/boot/bzImage -hda root-2.4.20.img \
1794 -append "root=/dev/hda"
1795 Connected to host network interface: tun0
1796 Waiting gdb connection on port 1234
1799 Then launch gdb on the 'vmlinux' executable:
1804 In gdb, connect to QEMU:
1806 (gdb) target remote localhost:1234
1809 Then you can use gdb normally. For example, type 'c' to launch the kernel:
1814 Here are some useful tips in order to use gdb on system code:
1818 Use @code{info reg} to display all the CPU registers.
1820 Use @code{x/10i $eip} to display the code at the PC position.
1822 Use @code{set architecture i8086} to dump 16 bit code. Then use
1823 @code{x/10i $cs*16+$eip} to dump the code at the PC position.
1826 Advanced debugging options:
1828 The default single stepping behavior is step with the IRQs and timer service routines off. It is set this way because when gdb executes a single step it expects to advance beyond the current instruction. With the IRQs and timer service routines on, a single step might jump into the one of the interrupt or exception vectors instead of executing the current instruction. This means you may hit the same breakpoint a number of times before executing the instruction gdb wants to have executed. Because there are rare circumstances where you want to single step into an interrupt vector the behavior can be controlled from GDB. There are three commands you can query and set the single step behavior:
1830 @item maintenance packet qqemu.sstepbits
1832 This will display the MASK bits used to control the single stepping IE:
1834 (gdb) maintenance packet qqemu.sstepbits
1835 sending: "qqemu.sstepbits"
1836 received: "ENABLE=1,NOIRQ=2,NOTIMER=4"
1838 @item maintenance packet qqemu.sstep
1840 This will display the current value of the mask used when single stepping IE:
1842 (gdb) maintenance packet qqemu.sstep
1843 sending: "qqemu.sstep"
1846 @item maintenance packet Qqemu.sstep=HEX_VALUE
1848 This will change the single step mask, so if wanted to enable IRQs on the single step, but not timers, you would use:
1850 (gdb) maintenance packet Qqemu.sstep=0x5
1851 sending: "qemu.sstep=0x5"
1856 @node pcsys_os_specific
1857 @section Target OS specific information
1861 To have access to SVGA graphic modes under X11, use the @code{vesa} or
1862 the @code{cirrus} X11 driver. For optimal performances, use 16 bit
1863 color depth in the guest and the host OS.
1865 When using a 2.6 guest Linux kernel, you should add the option
1866 @code{clock=pit} on the kernel command line because the 2.6 Linux
1867 kernels make very strict real time clock checks by default that QEMU
1868 cannot simulate exactly.
1870 When using a 2.6 guest Linux kernel, verify that the 4G/4G patch is
1871 not activated because QEMU is slower with this patch. The QEMU
1872 Accelerator Module is also much slower in this case. Earlier Fedora
1873 Core 3 Linux kernel (< 2.6.9-1.724_FC3) were known to incorporate this
1874 patch by default. Newer kernels don't have it.
1878 If you have a slow host, using Windows 95 is better as it gives the
1879 best speed. Windows 2000 is also a good choice.
1881 @subsubsection SVGA graphic modes support
1883 QEMU emulates a Cirrus Logic GD5446 Video
1884 card. All Windows versions starting from Windows 95 should recognize
1885 and use this graphic card. For optimal performances, use 16 bit color
1886 depth in the guest and the host OS.
1888 If you are using Windows XP as guest OS and if you want to use high
1889 resolution modes which the Cirrus Logic BIOS does not support (i.e. >=
1890 1280x1024x16), then you should use the VESA VBE virtual graphic card
1891 (option @option{-std-vga}).
1893 @subsubsection CPU usage reduction
1895 Windows 9x does not correctly use the CPU HLT
1896 instruction. The result is that it takes host CPU cycles even when
1897 idle. You can install the utility from
1898 @url{http://web.archive.org/web/20060212132151/http://www.user.cityline.ru/~maxamn/amnhltm.zip}
1899 to solve this problem. Note that no such tool is needed for NT, 2000 or XP.
1901 @subsubsection Windows 2000 disk full problem
1903 Windows 2000 has a bug which gives a disk full problem during its
1904 installation. When installing it, use the @option{-win2k-hack} QEMU
1905 option to enable a specific workaround. After Windows 2000 is
1906 installed, you no longer need this option (this option slows down the
1909 @subsubsection Windows 2000 shutdown
1911 Windows 2000 cannot automatically shutdown in QEMU although Windows 98
1912 can. It comes from the fact that Windows 2000 does not automatically
1913 use the APM driver provided by the BIOS.
1915 In order to correct that, do the following (thanks to Struan
1916 Bartlett): go to the Control Panel => Add/Remove Hardware & Next =>
1917 Add/Troubleshoot a device => Add a new device & Next => No, select the
1918 hardware from a list & Next => NT Apm/Legacy Support & Next => Next
1919 (again) a few times. Now the driver is installed and Windows 2000 now
1920 correctly instructs QEMU to shutdown at the appropriate moment.
1922 @subsubsection Share a directory between Unix and Windows
1924 See @ref{sec_invocation} about the help of the option
1925 @option{'-netdev user,smb=...'}.
1927 @subsubsection Windows XP security problem
1929 Some releases of Windows XP install correctly but give a security
1932 A problem is preventing Windows from accurately checking the
1933 license for this computer. Error code: 0x800703e6.
1936 The workaround is to install a service pack for XP after a boot in safe
1937 mode. Then reboot, and the problem should go away. Since there is no
1938 network while in safe mode, its recommended to download the full
1939 installation of SP1 or SP2 and transfer that via an ISO or using the
1940 vvfat block device ("-hdb fat:directory_which_holds_the_SP").
1942 @subsection MS-DOS and FreeDOS
1944 @subsubsection CPU usage reduction
1946 DOS does not correctly use the CPU HLT instruction. The result is that
1947 it takes host CPU cycles even when idle. You can install the utility from
1948 @url{http://web.archive.org/web/20051222085335/http://www.vmware.com/software/dosidle210.zip}
1949 to solve this problem.
1951 @node QEMU System emulator for non PC targets
1952 @chapter QEMU System emulator for non PC targets
1954 QEMU is a generic emulator and it emulates many non PC
1955 machines. Most of the options are similar to the PC emulator. The
1956 differences are mentioned in the following sections.
1959 * PowerPC System emulator::
1960 * Sparc32 System emulator::
1961 * Sparc64 System emulator::
1962 * MIPS System emulator::
1963 * ARM System emulator::
1964 * ColdFire System emulator::
1965 * Cris System emulator::
1966 * Microblaze System emulator::
1967 * SH4 System emulator::
1968 * Xtensa System emulator::
1971 @node PowerPC System emulator
1972 @section PowerPC System emulator
1973 @cindex system emulation (PowerPC)
1975 Use the executable @file{qemu-system-ppc} to simulate a complete PREP
1976 or PowerMac PowerPC system.
1978 QEMU emulates the following PowerMac peripherals:
1982 UniNorth or Grackle PCI Bridge
1984 PCI VGA compatible card with VESA Bochs Extensions
1986 2 PMAC IDE interfaces with hard disk and CD-ROM support
1992 VIA-CUDA with ADB keyboard and mouse.
1995 QEMU emulates the following PREP peripherals:
2001 PCI VGA compatible card with VESA Bochs Extensions
2003 2 IDE interfaces with hard disk and CD-ROM support
2007 NE2000 network adapters
2011 PREP Non Volatile RAM
2013 PC compatible keyboard and mouse.
2016 QEMU uses the Open Hack'Ware Open Firmware Compatible BIOS.
2018 Since version 0.9.1, QEMU uses OpenBIOS @url{http://www.openbios.org/}
2019 for the g3beige and mac99 PowerMac machines. OpenBIOS is a free (GPL
2020 v2) portable firmware implementation. The goal is to implement a 100%
2021 IEEE 1275-1994 (referred to as Open Firmware) compliant firmware.
2023 @c man begin OPTIONS
2025 The following options are specific to the PowerPC emulation:
2029 @item -g @var{W}x@var{H}[x@var{DEPTH}]
2031 Set the initial VGA graphic mode. The default is 800x600x32.
2033 @item -prom-env @var{string}
2035 Set OpenBIOS variables in NVRAM, for example:
2038 qemu-system-ppc -prom-env 'auto-boot?=false' \
2039 -prom-env 'boot-device=hd:2,\yaboot' \
2040 -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
2043 These variables are not used by Open Hack'Ware.
2049 @node Sparc32 System emulator
2050 @section Sparc32 System emulator
2051 @cindex system emulation (Sparc32)
2053 Use the executable @file{qemu-system-sparc} to simulate the following
2054 Sun4m architecture machines:
2069 SPARCstation Voyager
2076 The emulation is somewhat complete. SMP up to 16 CPUs is supported,
2077 but Linux limits the number of usable CPUs to 4.
2079 QEMU emulates the following sun4m peripherals:
2085 TCX or cgthree Frame buffer
2087 Lance (Am7990) Ethernet
2089 Non Volatile RAM M48T02/M48T08
2091 Slave I/O: timers, interrupt controllers, Zilog serial ports, keyboard
2092 and power/reset logic
2094 ESP SCSI controller with hard disk and CD-ROM support
2096 Floppy drive (not on SS-600MP)
2098 CS4231 sound device (only on SS-5, not working yet)
2101 The number of peripherals is fixed in the architecture. Maximum
2102 memory size depends on the machine type, for SS-5 it is 256MB and for
2105 Since version 0.8.2, QEMU uses OpenBIOS
2106 @url{http://www.openbios.org/}. OpenBIOS is a free (GPL v2) portable
2107 firmware implementation. The goal is to implement a 100% IEEE
2108 1275-1994 (referred to as Open Firmware) compliant firmware.
2110 A sample Linux 2.6 series kernel and ram disk image are available on
2111 the QEMU web site. There are still issues with NetBSD and OpenBSD, but
2112 most kernel versions work. Please note that currently older Solaris kernels
2113 don't work probably due to interface issues between OpenBIOS and
2116 @c man begin OPTIONS
2118 The following options are specific to the Sparc32 emulation:
2122 @item -g @var{W}x@var{H}x[x@var{DEPTH}]
2124 Set the initial graphics mode. For TCX, the default is 1024x768x8 with the
2125 option of 1024x768x24. For cgthree, the default is 1024x768x8 with the option
2126 of 1152x900x8 for people who wish to use OBP.
2128 @item -prom-env @var{string}
2130 Set OpenBIOS variables in NVRAM, for example:
2133 qemu-system-sparc -prom-env 'auto-boot?=false' \
2134 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
2137 @item -M [SS-4|SS-5|SS-10|SS-20|SS-600MP|LX|Voyager|SPARCClassic] [|SPARCbook]
2139 Set the emulated machine type. Default is SS-5.
2145 @node Sparc64 System emulator
2146 @section Sparc64 System emulator
2147 @cindex system emulation (Sparc64)
2149 Use the executable @file{qemu-system-sparc64} to simulate a Sun4u
2150 (UltraSPARC PC-like machine), Sun4v (T1 PC-like machine), or generic
2151 Niagara (T1) machine. The Sun4u emulator is mostly complete, being
2152 able to run Linux, NetBSD and OpenBSD in headless (-nographic) mode. The
2153 Sun4v emulator is still a work in progress.
2155 The Niagara T1 emulator makes use of firmware and OS binaries supplied in the S10image/ directory
2156 of the OpenSPARC T1 project @url{http://download.oracle.com/technetwork/systems/opensparc/OpenSPARCT1_Arch.1.5.tar.bz2}
2157 and is able to boot the disk.s10hw2 Solaris image.
2159 qemu-system-sparc64 -M niagara -L /path-to/S10image/ \
2161 -drive if=pflash,readonly=on,file=/S10image/disk.s10hw2
2165 QEMU emulates the following peripherals:
2169 UltraSparc IIi APB PCI Bridge
2171 PCI VGA compatible card with VESA Bochs Extensions
2173 PS/2 mouse and keyboard
2175 Non Volatile RAM M48T59
2177 PC-compatible serial ports
2179 2 PCI IDE interfaces with hard disk and CD-ROM support
2184 @c man begin OPTIONS
2186 The following options are specific to the Sparc64 emulation:
2190 @item -prom-env @var{string}
2192 Set OpenBIOS variables in NVRAM, for example:
2195 qemu-system-sparc64 -prom-env 'auto-boot?=false'
2198 @item -M [sun4u|sun4v|niagara]
2200 Set the emulated machine type. The default is sun4u.
2206 @node MIPS System emulator
2207 @section MIPS System emulator
2208 @cindex system emulation (MIPS)
2210 Four executables cover simulation of 32 and 64-bit MIPS systems in
2211 both endian options, @file{qemu-system-mips}, @file{qemu-system-mipsel}
2212 @file{qemu-system-mips64} and @file{qemu-system-mips64el}.
2213 Five different machine types are emulated:
2217 A generic ISA PC-like machine "mips"
2219 The MIPS Malta prototype board "malta"
2221 An ACER Pica "pica61". This machine needs the 64-bit emulator.
2223 MIPS emulator pseudo board "mipssim"
2225 A MIPS Magnum R4000 machine "magnum". This machine needs the 64-bit emulator.
2228 The generic emulation is supported by Debian 'Etch' and is able to
2229 install Debian into a virtual disk image. The following devices are
2234 A range of MIPS CPUs, default is the 24Kf
2236 PC style serial port
2243 The Malta emulation supports the following devices:
2247 Core board with MIPS 24Kf CPU and Galileo system controller
2249 PIIX4 PCI/USB/SMbus controller
2251 The Multi-I/O chip's serial device
2253 PCI network cards (PCnet32 and others)
2255 Malta FPGA serial device
2257 Cirrus (default) or any other PCI VGA graphics card
2260 The ACER Pica emulation supports:
2266 PC-style IRQ and DMA controllers
2273 The mipssim pseudo board emulation provides an environment similar
2274 to what the proprietary MIPS emulator uses for running Linux.
2279 A range of MIPS CPUs, default is the 24Kf
2281 PC style serial port
2283 MIPSnet network emulation
2286 The MIPS Magnum R4000 emulation supports:
2292 PC-style IRQ controller
2302 @node ARM System emulator
2303 @section ARM System emulator
2304 @cindex system emulation (ARM)
2306 Use the executable @file{qemu-system-arm} to simulate a ARM
2307 machine. The ARM Integrator/CP board is emulated with the following
2312 ARM926E, ARM1026E, ARM946E, ARM1136 or Cortex-A8 CPU
2316 SMC 91c111 Ethernet adapter
2318 PL110 LCD controller
2320 PL050 KMI with PS/2 keyboard and mouse.
2322 PL181 MultiMedia Card Interface with SD card.
2325 The ARM Versatile baseboard is emulated with the following devices:
2329 ARM926E, ARM1136 or Cortex-A8 CPU
2331 PL190 Vectored Interrupt Controller
2335 SMC 91c111 Ethernet adapter
2337 PL110 LCD controller
2339 PL050 KMI with PS/2 keyboard and mouse.
2341 PCI host bridge. Note the emulated PCI bridge only provides access to
2342 PCI memory space. It does not provide access to PCI IO space.
2343 This means some devices (eg. ne2k_pci NIC) are not usable, and others
2344 (eg. rtl8139 NIC) are only usable when the guest drivers use the memory
2345 mapped control registers.
2347 PCI OHCI USB controller.
2349 LSI53C895A PCI SCSI Host Bus Adapter with hard disk and CD-ROM devices.
2351 PL181 MultiMedia Card Interface with SD card.
2354 Several variants of the ARM RealView baseboard are emulated,
2355 including the EB, PB-A8 and PBX-A9. Due to interactions with the
2356 bootloader, only certain Linux kernel configurations work out
2357 of the box on these boards.
2359 Kernels for the PB-A8 board should have CONFIG_REALVIEW_HIGH_PHYS_OFFSET
2360 enabled in the kernel, and expect 512M RAM. Kernels for The PBX-A9 board
2361 should have CONFIG_SPARSEMEM enabled, CONFIG_REALVIEW_HIGH_PHYS_OFFSET
2362 disabled and expect 1024M RAM.
2364 The following devices are emulated:
2368 ARM926E, ARM1136, ARM11MPCore, Cortex-A8 or Cortex-A9 MPCore CPU
2370 ARM AMBA Generic/Distributed Interrupt Controller
2374 SMC 91c111 or SMSC LAN9118 Ethernet adapter
2376 PL110 LCD controller
2378 PL050 KMI with PS/2 keyboard and mouse
2382 PCI OHCI USB controller
2384 LSI53C895A PCI SCSI Host Bus Adapter with hard disk and CD-ROM devices
2386 PL181 MultiMedia Card Interface with SD card.
2389 The XScale-based clamshell PDA models ("Spitz", "Akita", "Borzoi"
2390 and "Terrier") emulation includes the following peripherals:
2394 Intel PXA270 System-on-chip (ARM V5TE core)
2398 IBM/Hitachi DSCM microdrive in a PXA PCMCIA slot - not in "Akita"
2400 On-chip OHCI USB controller
2402 On-chip LCD controller
2404 On-chip Real Time Clock
2406 TI ADS7846 touchscreen controller on SSP bus
2408 Maxim MAX1111 analog-digital converter on I@math{^2}C bus
2410 GPIO-connected keyboard controller and LEDs
2412 Secure Digital card connected to PXA MMC/SD host
2416 WM8750 audio CODEC on I@math{^2}C and I@math{^2}S busses
2419 The Palm Tungsten|E PDA (codename "Cheetah") emulation includes the
2424 Texas Instruments OMAP310 System-on-chip (ARM 925T core)
2426 ROM and RAM memories (ROM firmware image can be loaded with -option-rom)
2428 On-chip LCD controller
2430 On-chip Real Time Clock
2432 TI TSC2102i touchscreen controller / analog-digital converter / Audio
2433 CODEC, connected through MicroWire and I@math{^2}S busses
2435 GPIO-connected matrix keypad
2437 Secure Digital card connected to OMAP MMC/SD host
2442 Nokia N800 and N810 internet tablets (known also as RX-34 and RX-44 / 48)
2443 emulation supports the following elements:
2447 Texas Instruments OMAP2420 System-on-chip (ARM 1136 core)
2449 RAM and non-volatile OneNAND Flash memories
2451 Display connected to EPSON remote framebuffer chip and OMAP on-chip
2452 display controller and a LS041y3 MIPI DBI-C controller
2454 TI TSC2301 (in N800) and TI TSC2005 (in N810) touchscreen controllers
2455 driven through SPI bus
2457 National Semiconductor LM8323-controlled qwerty keyboard driven
2458 through I@math{^2}C bus
2460 Secure Digital card connected to OMAP MMC/SD host
2462 Three OMAP on-chip UARTs and on-chip STI debugging console
2464 A Bluetooth(R) transceiver and HCI connected to an UART
2466 Mentor Graphics "Inventra" dual-role USB controller embedded in a TI
2467 TUSB6010 chip - only USB host mode is supported
2469 TI TMP105 temperature sensor driven through I@math{^2}C bus
2471 TI TWL92230C power management companion with an RTC on I@math{^2}C bus
2473 Nokia RETU and TAHVO multi-purpose chips with an RTC, connected
2477 The Luminary Micro Stellaris LM3S811EVB emulation includes the following
2484 64k Flash and 8k SRAM.
2486 Timers, UARTs, ADC and I@math{^2}C interface.
2488 OSRAM Pictiva 96x16 OLED with SSD0303 controller on I@math{^2}C bus.
2491 The Luminary Micro Stellaris LM3S6965EVB emulation includes the following
2498 256k Flash and 64k SRAM.
2500 Timers, UARTs, ADC, I@math{^2}C and SSI interfaces.
2502 OSRAM Pictiva 128x64 OLED with SSD0323 controller connected via SSI.
2505 The Freecom MusicPal internet radio emulation includes the following
2510 Marvell MV88W8618 ARM core.
2512 32 MB RAM, 256 KB SRAM, 8 MB flash.
2516 MV88W8xx8 Ethernet controller
2518 MV88W8618 audio controller, WM8750 CODEC and mixer
2520 128×64 display with brightness control
2522 2 buttons, 2 navigation wheels with button function
2525 The Siemens SX1 models v1 and v2 (default) basic emulation.
2526 The emulation includes the following elements:
2530 Texas Instruments OMAP310 System-on-chip (ARM 925T core)
2532 ROM and RAM memories (ROM firmware image can be loaded with -pflash)
2534 1 Flash of 16MB and 1 Flash of 8MB
2538 On-chip LCD controller
2540 On-chip Real Time Clock
2542 Secure Digital card connected to OMAP MMC/SD host
2547 A Linux 2.6 test image is available on the QEMU web site. More
2548 information is available in the QEMU mailing-list archive.
2550 @c man begin OPTIONS
2552 The following options are specific to the ARM emulation:
2557 Enable semihosting syscall emulation.
2559 On ARM this implements the "Angel" interface.
2561 Note that this allows guest direct access to the host filesystem,
2562 so should only be used with trusted guest OS.
2566 @node ColdFire System emulator
2567 @section ColdFire System emulator
2568 @cindex system emulation (ColdFire)
2569 @cindex system emulation (M68K)
2571 Use the executable @file{qemu-system-m68k} to simulate a ColdFire machine.
2572 The emulator is able to boot a uClinux kernel.
2574 The M5208EVB emulation includes the following devices:
2578 MCF5208 ColdFire V2 Microprocessor (ISA A+ with EMAC).
2580 Three Two on-chip UARTs.
2582 Fast Ethernet Controller (FEC)
2585 The AN5206 emulation includes the following devices:
2589 MCF5206 ColdFire V2 Microprocessor.
2594 @c man begin OPTIONS
2596 The following options are specific to the ColdFire emulation:
2601 Enable semihosting syscall emulation.
2603 On M68K this implements the "ColdFire GDB" interface used by libgloss.
2605 Note that this allows guest direct access to the host filesystem,
2606 so should only be used with trusted guest OS.
2610 @node Cris System emulator
2611 @section Cris System emulator
2612 @cindex system emulation (Cris)
2616 @node Microblaze System emulator
2617 @section Microblaze System emulator
2618 @cindex system emulation (Microblaze)
2622 @node SH4 System emulator
2623 @section SH4 System emulator
2624 @cindex system emulation (SH4)
2628 @node Xtensa System emulator
2629 @section Xtensa System emulator
2630 @cindex system emulation (Xtensa)
2632 Two executables cover simulation of both Xtensa endian options,
2633 @file{qemu-system-xtensa} and @file{qemu-system-xtensaeb}.
2634 Two different machine types are emulated:
2638 Xtensa emulator pseudo board "sim"
2640 Avnet LX60/LX110/LX200 board
2643 The sim pseudo board emulation provides an environment similar
2644 to one provided by the proprietary Tensilica ISS.
2649 A range of Xtensa CPUs, default is the DC232B
2651 Console and filesystem access via semihosting calls
2654 The Avnet LX60/LX110/LX200 emulation supports:
2658 A range of Xtensa CPUs, default is the DC232B
2662 OpenCores 10/100 Mbps Ethernet MAC
2665 @c man begin OPTIONS
2667 The following options are specific to the Xtensa emulation:
2672 Enable semihosting syscall emulation.
2674 Xtensa semihosting provides basic file IO calls, such as open/read/write/seek/select.
2675 Tensilica baremetal libc for ISS and linux platform "sim" use this interface.
2677 Note that this allows guest direct access to the host filesystem,
2678 so should only be used with trusted guest OS.
2682 @node QEMU Guest Agent
2683 @chapter QEMU Guest Agent invocation
2685 @include qemu-ga.texi
2687 @node QEMU User space emulator
2688 @chapter QEMU User space emulator
2691 * Supported Operating Systems ::
2693 * Linux User space emulator::
2694 * BSD User space emulator ::
2697 @node Supported Operating Systems
2698 @section Supported Operating Systems
2700 The following OS are supported in user space emulation:
2704 Linux (referred as qemu-linux-user)
2706 BSD (referred as qemu-bsd-user)
2712 QEMU user space emulation has the following notable features:
2715 @item System call translation:
2716 QEMU includes a generic system call translator. This means that
2717 the parameters of the system calls can be converted to fix
2718 endianness and 32/64-bit mismatches between hosts and targets.
2719 IOCTLs can be converted too.
2721 @item POSIX signal handling:
2722 QEMU can redirect to the running program all signals coming from
2723 the host (such as @code{SIGALRM}), as well as synthesize signals from
2724 virtual CPU exceptions (for example @code{SIGFPE} when the program
2725 executes a division by zero).
2727 QEMU relies on the host kernel to emulate most signal system
2728 calls, for example to emulate the signal mask. On Linux, QEMU
2729 supports both normal and real-time signals.
2732 On Linux, QEMU can emulate the @code{clone} syscall and create a real
2733 host thread (with a separate virtual CPU) for each emulated thread.
2734 Note that not all targets currently emulate atomic operations correctly.
2735 x86 and ARM use a global lock in order to preserve their semantics.
2738 QEMU was conceived so that ultimately it can emulate itself. Although
2739 it is not very useful, it is an important test to show the power of the
2742 @node Linux User space emulator
2743 @section Linux User space emulator
2748 * Command line options::
2753 @subsection Quick Start
2755 In order to launch a Linux process, QEMU needs the process executable
2756 itself and all the target (x86) dynamic libraries used by it.
2760 @item On x86, you can just try to launch any process by using the native
2764 qemu-i386 -L / /bin/ls
2767 @code{-L /} tells that the x86 dynamic linker must be searched with a
2770 @item Since QEMU is also a linux process, you can launch QEMU with
2771 QEMU (NOTE: you can only do that if you compiled QEMU from the sources):
2774 qemu-i386 -L / qemu-i386 -L / /bin/ls
2777 @item On non x86 CPUs, you need first to download at least an x86 glibc
2778 (@file{qemu-runtime-i386-XXX-.tar.gz} on the QEMU web page). Ensure that
2779 @code{LD_LIBRARY_PATH} is not set:
2782 unset LD_LIBRARY_PATH
2785 Then you can launch the precompiled @file{ls} x86 executable:
2788 qemu-i386 tests/i386/ls
2790 You can look at @file{scripts/qemu-binfmt-conf.sh} so that
2791 QEMU is automatically launched by the Linux kernel when you try to
2792 launch x86 executables. It requires the @code{binfmt_misc} module in the
2795 @item The x86 version of QEMU is also included. You can try weird things such as:
2797 qemu-i386 /usr/local/qemu-i386/bin/qemu-i386 \
2798 /usr/local/qemu-i386/bin/ls-i386
2804 @subsection Wine launch
2808 @item Ensure that you have a working QEMU with the x86 glibc
2809 distribution (see previous section). In order to verify it, you must be
2813 qemu-i386 /usr/local/qemu-i386/bin/ls-i386
2816 @item Download the binary x86 Wine install
2817 (@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page).
2819 @item Configure Wine on your account. Look at the provided script
2820 @file{/usr/local/qemu-i386/@/bin/wine-conf.sh}. Your previous
2821 @code{$@{HOME@}/.wine} directory is saved to @code{$@{HOME@}/.wine.org}.
2823 @item Then you can try the example @file{putty.exe}:
2826 qemu-i386 /usr/local/qemu-i386/wine/bin/wine \
2827 /usr/local/qemu-i386/wine/c/Program\ Files/putty.exe
2832 @node Command line options
2833 @subsection Command line options
2836 @command{qemu-i386} [@option{-h]} [@option{-d]} [@option{-L} @var{path}] [@option{-s} @var{size}] [@option{-cpu} @var{model}] [@option{-g} @var{port}] [@option{-B} @var{offset}] [@option{-R} @var{size}] @var{program} [@var{arguments}...]
2843 Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)
2845 Set the x86 stack size in bytes (default=524288)
2847 Select CPU model (-cpu help for list and additional feature selection)
2848 @item -E @var{var}=@var{value}
2849 Set environment @var{var} to @var{value}.
2851 Remove @var{var} from the environment.
2853 Offset guest address by the specified number of bytes. This is useful when
2854 the address region required by guest applications is reserved on the host.
2855 This option is currently only supported on some hosts.
2857 Pre-allocate a guest virtual address space of the given size (in bytes).
2858 "G", "M", and "k" suffixes may be used when specifying the size.
2865 Activate logging of the specified items (use '-d help' for a list of log items)
2867 Act as if the host page size was 'pagesize' bytes
2869 Wait gdb connection to port
2871 Run the emulation in single step mode.
2874 Environment variables:
2878 Print system calls and arguments similar to the 'strace' program
2879 (NOTE: the actual 'strace' program will not work because the user
2880 space emulator hasn't implemented ptrace). At the moment this is
2881 incomplete. All system calls that don't have a specific argument
2882 format are printed with information for six arguments. Many
2883 flag-style arguments don't have decoders and will show up as numbers.
2886 @node Other binaries
2887 @subsection Other binaries
2889 @cindex user mode (Alpha)
2890 @command{qemu-alpha} TODO.
2892 @cindex user mode (ARM)
2893 @command{qemu-armeb} TODO.
2895 @cindex user mode (ARM)
2896 @command{qemu-arm} is also capable of running ARM "Angel" semihosted ELF
2897 binaries (as implemented by the arm-elf and arm-eabi Newlib/GDB
2898 configurations), and arm-uclinux bFLT format binaries.
2900 @cindex user mode (ColdFire)
2901 @cindex user mode (M68K)
2902 @command{qemu-m68k} is capable of running semihosted binaries using the BDM
2903 (m5xxx-ram-hosted.ld) or m68k-sim (sim.ld) syscall interfaces, and
2904 coldfire uClinux bFLT format binaries.
2906 The binary format is detected automatically.
2908 @cindex user mode (Cris)
2909 @command{qemu-cris} TODO.
2911 @cindex user mode (i386)
2912 @command{qemu-i386} TODO.
2913 @command{qemu-x86_64} TODO.
2915 @cindex user mode (Microblaze)
2916 @command{qemu-microblaze} TODO.
2918 @cindex user mode (MIPS)
2919 @command{qemu-mips} TODO.
2920 @command{qemu-mipsel} TODO.
2922 @cindex user mode (NiosII)
2923 @command{qemu-nios2} TODO.
2925 @cindex user mode (PowerPC)
2926 @command{qemu-ppc64abi32} TODO.
2927 @command{qemu-ppc64} TODO.
2928 @command{qemu-ppc} TODO.
2930 @cindex user mode (SH4)
2931 @command{qemu-sh4eb} TODO.
2932 @command{qemu-sh4} TODO.
2934 @cindex user mode (SPARC)
2935 @command{qemu-sparc} can execute Sparc32 binaries (Sparc32 CPU, 32 bit ABI).
2937 @command{qemu-sparc32plus} can execute Sparc32 and SPARC32PLUS binaries
2938 (Sparc64 CPU, 32 bit ABI).
2940 @command{qemu-sparc64} can execute some Sparc64 (Sparc64 CPU, 64 bit ABI) and
2941 SPARC32PLUS binaries (Sparc64 CPU, 32 bit ABI).
2943 @node BSD User space emulator
2944 @section BSD User space emulator
2949 * BSD Command line options::
2953 @subsection BSD Status
2957 target Sparc64 on Sparc64: Some trivial programs work.
2960 @node BSD Quick Start
2961 @subsection Quick Start
2963 In order to launch a BSD process, QEMU needs the process executable
2964 itself and all the target dynamic libraries used by it.
2968 @item On Sparc64, you can just try to launch any process by using the native
2972 qemu-sparc64 /bin/ls
2977 @node BSD Command line options
2978 @subsection Command line options
2981 @command{qemu-sparc64} [@option{-h]} [@option{-d]} [@option{-L} @var{path}] [@option{-s} @var{size}] [@option{-bsd} @var{type}] @var{program} [@var{arguments}...]
2988 Set the library root path (default=/)
2990 Set the stack size in bytes (default=524288)
2991 @item -ignore-environment
2992 Start with an empty environment. Without this option,
2993 the initial environment is a copy of the caller's environment.
2994 @item -E @var{var}=@var{value}
2995 Set environment @var{var} to @var{value}.
2997 Remove @var{var} from the environment.
2999 Set the type of the emulated BSD Operating system. Valid values are
3000 FreeBSD, NetBSD and OpenBSD (default).
3007 Activate logging of the specified items (use '-d help' for a list of log items)
3009 Act as if the host page size was 'pagesize' bytes
3011 Run the emulation in single step mode.
3015 @include qemu-tech.texi
3020 QEMU is a trademark of Fabrice Bellard.
3022 QEMU is released under the
3023 @url{https://www.gnu.org/licenses/gpl-2.0.txt,GNU General Public License},
3024 version 2. Parts of QEMU have specific licenses, see file
3025 @url{http://git.qemu.org/?p=qemu.git;a=blob_plain;f=LICENSE,LICENSE}.
3039 @section Concept Index
3040 This is the main index. Should we combine all keywords in one index? TODO
3043 @node Function Index
3044 @section Function Index
3045 This index could be used for command line options and monitor functions.
3048 @node Keystroke Index
3049 @section Keystroke Index
3051 This is a list of all keystrokes which have a special function
3052 in system emulation.
3057 @section Program Index
3060 @node Data Type Index
3061 @section Data Type Index
3063 This index could be used for qdev device names and options.
3067 @node Variable Index
3068 @section Variable Index