1 \input texinfo @c -*- texinfo -*-
3 @setfilename qemu-doc.info
7 @documentencoding UTF-8
9 @settitle QEMU version @value{VERSION} User Documentation
14 @set qemu_system qemu-system-x86_64
15 @set qemu_system_x86 qemu-system-x86_64
19 * QEMU: (qemu-doc). The QEMU Emulator User Documentation.
26 @center @titlefont{QEMU version @value{VERSION}}
28 @center @titlefont{User Documentation}
39 * QEMU PC System emulator::
40 * QEMU System emulator for non PC targets::
42 * QEMU User space emulator::
43 * System requirements::
45 * Implementation notes::
46 * Deprecated features::
47 * Supported build platforms::
59 * intro_features:: Features
65 QEMU is a FAST! processor emulator using dynamic translation to
66 achieve good emulation speed.
68 @cindex operating modes
69 QEMU has two operating modes:
72 @cindex system emulation
73 @item Full system emulation. In this mode, QEMU emulates a full system (for
74 example a PC), including one or several processors and various
75 peripherals. It can be used to launch different Operating Systems
76 without rebooting the PC or to debug system code.
78 @cindex user mode emulation
79 @item User mode emulation. In this mode, QEMU can launch
80 processes compiled for one CPU on another CPU. It can be used to
81 launch the Wine Windows API emulator (@url{https://www.winehq.org}) or
82 to ease cross-compilation and cross-debugging.
86 QEMU has the following features:
89 @item QEMU can run without a host kernel driver and yet gives acceptable
90 performance. It uses dynamic translation to native code for reasonable speed,
91 with support for self-modifying code and precise exceptions.
93 @item It is portable to several operating systems (GNU/Linux, *BSD, Mac OS X,
94 Windows) and architectures.
96 @item It performs accurate software emulation of the FPU.
99 QEMU user mode emulation has the following features:
101 @item Generic Linux system call converter, including most ioctls.
103 @item clone() emulation using native CPU clone() to use Linux scheduler for threads.
105 @item Accurate signal handling by remapping host signals to target signals.
108 QEMU full system emulation has the following features:
111 QEMU uses a full software MMU for maximum portability.
114 QEMU can optionally use an in-kernel accelerator, like kvm. The accelerators
115 execute most of the guest code natively, while
116 continuing to emulate the rest of the machine.
119 Various hardware devices can be emulated and in some cases, host
120 devices (e.g. serial and parallel ports, USB, drives) can be used
121 transparently by the guest Operating System. Host device passthrough
122 can be used for talking to external physical peripherals (e.g. a
123 webcam, modem or tape drive).
126 Symmetric multiprocessing (SMP) support. Currently, an in-kernel
127 accelerator is required to use more than one host CPU for emulation.
132 @node QEMU PC System emulator
133 @chapter QEMU PC System emulator
134 @cindex system emulation (PC)
137 * pcsys_introduction:: Introduction
138 * pcsys_quickstart:: Quick Start
139 * sec_invocation:: Invocation
140 * pcsys_keys:: Keys in the graphical frontends
141 * mux_keys:: Keys in the character backend multiplexer
142 * pcsys_monitor:: QEMU Monitor
143 * cpu_models:: CPU models
144 * disk_images:: Disk Images
145 * pcsys_network:: Network emulation
146 * pcsys_other_devs:: Other Devices
147 * direct_linux_boot:: Direct Linux Boot
148 * pcsys_usb:: USB emulation
149 * vnc_security:: VNC security
150 * network_tls:: TLS setup for network services
151 * gdb_usage:: GDB usage
152 * pcsys_os_specific:: Target OS specific information
155 @node pcsys_introduction
156 @section Introduction
158 @c man begin DESCRIPTION
160 The QEMU PC System emulator simulates the
161 following peripherals:
165 i440FX host PCI bridge and PIIX3 PCI to ISA bridge
167 Cirrus CLGD 5446 PCI VGA card or dummy VGA card with Bochs VESA
168 extensions (hardware level, including all non standard modes).
170 PS/2 mouse and keyboard
172 2 PCI IDE interfaces with hard disk and CD-ROM support
176 PCI and ISA network adapters
180 IPMI BMC, either and internal or external one
182 Creative SoundBlaster 16 sound card
184 ENSONIQ AudioPCI ES1370 sound card
186 Intel 82801AA AC97 Audio compatible sound card
188 Intel HD Audio Controller and HDA codec
190 Adlib (OPL2) - Yamaha YM3812 compatible chip
192 Gravis Ultrasound GF1 sound card
194 CS4231A compatible sound card
196 PCI UHCI, OHCI, EHCI or XHCI USB controller and a virtual USB-1.1 hub.
199 SMP is supported with up to 255 CPUs.
201 QEMU uses the PC BIOS from the Seabios project and the Plex86/Bochs LGPL
204 QEMU uses YM3812 emulation by Tatsuyuki Satoh.
206 QEMU uses GUS emulation (GUSEMU32 @url{http://www.deinmeister.de/gusemu/})
207 by Tibor "TS" Schütz.
209 Note that, by default, GUS shares IRQ(7) with parallel ports and so
210 QEMU must be told to not have parallel ports to have working GUS.
213 @value{qemu_system_x86} dos.img -soundhw gus -parallel none
218 @value{qemu_system_x86} dos.img -device gus,irq=5
221 Or some other unclaimed IRQ.
223 CS4231A is the chip used in Windows Sound System and GUSMAX products
227 @node pcsys_quickstart
231 Download and uncompress a hard disk image with Linux installed (e.g.
232 @file{linux.img}) and type:
235 @value{qemu_system} linux.img
238 Linux should boot and give you a prompt.
244 @c man begin SYNOPSIS
245 @command{@value{qemu_system}} [@var{options}] [@var{disk_image}]
250 @var{disk_image} is a raw hard disk image for IDE hard disk 0. Some
251 targets do not need a disk image.
253 @include qemu-options.texi
257 @subsection Device URL Syntax
258 @c TODO merge this with section Disk Images
262 In addition to using normal file images for the emulated storage devices,
263 QEMU can also use networked resources such as iSCSI devices. These are
264 specified using a special URL syntax.
268 iSCSI support allows QEMU to access iSCSI resources directly and use as
269 images for the guest storage. Both disk and cdrom images are supported.
271 Syntax for specifying iSCSI LUNs is
272 ``iscsi://<target-ip>[:<port>]/<target-iqn>/<lun>''
274 By default qemu will use the iSCSI initiator-name
275 'iqn.2008-11.org.linux-kvm[:<name>]' but this can also be set from the command
276 line or a configuration file.
278 Since version Qemu 2.4 it is possible to specify a iSCSI request timeout to detect
279 stalled requests and force a reestablishment of the session. The timeout
280 is specified in seconds. The default is 0 which means no timeout. Libiscsi
281 1.15.0 or greater is required for this feature.
283 Example (without authentication):
285 @value{qemu_system} -iscsi initiator-name=iqn.2001-04.com.example:my-initiator \
286 -cdrom iscsi://192.0.2.1/iqn.2001-04.com.example/2 \
287 -drive file=iscsi://192.0.2.1/iqn.2001-04.com.example/1
290 Example (CHAP username/password via URL):
292 @value{qemu_system} -drive file=iscsi://user%password@@192.0.2.1/iqn.2001-04.com.example/1
295 Example (CHAP username/password via environment variables):
297 LIBISCSI_CHAP_USERNAME="user" \
298 LIBISCSI_CHAP_PASSWORD="password" \
299 @value{qemu_system} -drive file=iscsi://192.0.2.1/iqn.2001-04.com.example/1
303 QEMU supports NBD (Network Block Devices) both using TCP protocol as well
304 as Unix Domain Sockets.
306 Syntax for specifying a NBD device using TCP
307 ``nbd:<server-ip>:<port>[:exportname=<export>]''
309 Syntax for specifying a NBD device using Unix Domain Sockets
310 ``nbd:unix:<domain-socket>[:exportname=<export>]''
314 @value{qemu_system} --drive file=nbd:192.0.2.1:30000
317 Example for Unix Domain Sockets
319 @value{qemu_system} --drive file=nbd:unix:/tmp/nbd-socket
323 QEMU supports SSH (Secure Shell) access to remote disks.
327 @value{qemu_system} -drive file=ssh://user@@host/path/to/disk.img
328 @value{qemu_system} -drive file.driver=ssh,file.user=user,file.host=host,file.port=22,file.path=/path/to/disk.img
331 Currently authentication must be done using ssh-agent. Other
332 authentication methods may be supported in future.
335 Sheepdog is a distributed storage system for QEMU.
336 QEMU supports using either local sheepdog devices or remote networked
339 Syntax for specifying a sheepdog device
341 sheepdog[+tcp|+unix]://[host:port]/vdiname[?socket=path][#snapid|#tag]
346 @value{qemu_system} --drive file=sheepdog://192.0.2.1:30000/MyVirtualMachine
349 See also @url{https://sheepdog.github.io/sheepdog/}.
352 GlusterFS is a user space distributed file system.
353 QEMU supports the use of GlusterFS volumes for hosting VM disk images using
354 TCP, Unix Domain Sockets and RDMA transport protocols.
356 Syntax for specifying a VM disk image on GlusterFS volume is
360 gluster[+type]://[host[:port]]/volume/path[?socket=...][,debug=N][,logfile=...]
363 'json:@{"driver":"qcow2","file":@{"driver":"gluster","volume":"testvol","path":"a.img","debug":N,"logfile":"...",
364 @ "server":[@{"type":"tcp","host":"...","port":"..."@},
365 @ @{"type":"unix","socket":"..."@}]@}@}'
372 @value{qemu_system} --drive file=gluster://192.0.2.1/testvol/a.img,
373 @ file.debug=9,file.logfile=/var/log/qemu-gluster.log
376 @value{qemu_system} 'json:@{"driver":"qcow2",
377 @ "file":@{"driver":"gluster",
378 @ "volume":"testvol","path":"a.img",
379 @ "debug":9,"logfile":"/var/log/qemu-gluster.log",
380 @ "server":[@{"type":"tcp","host":"1.2.3.4","port":24007@},
381 @ @{"type":"unix","socket":"/var/run/glusterd.socket"@}]@}@}'
382 @value{qemu_system} -drive driver=qcow2,file.driver=gluster,file.volume=testvol,file.path=/path/a.img,
383 @ file.debug=9,file.logfile=/var/log/qemu-gluster.log,
384 @ file.server.0.type=tcp,file.server.0.host=1.2.3.4,file.server.0.port=24007,
385 @ file.server.1.type=unix,file.server.1.socket=/var/run/glusterd.socket
388 See also @url{http://www.gluster.org}.
390 @item HTTP/HTTPS/FTP/FTPS
391 QEMU supports read-only access to files accessed over http(s) and ftp(s).
393 Syntax using a single filename:
395 <protocol>://[<username>[:<password>]@@]<host>/<path>
401 'http', 'https', 'ftp', or 'ftps'.
404 Optional username for authentication to the remote server.
407 Optional password for authentication to the remote server.
410 Address of the remote server.
413 Path on the remote server, including any query string.
416 The following options are also supported:
419 The full URL when passing options to the driver explicitly.
422 The amount of data to read ahead with each range request to the remote server.
423 This value may optionally have the suffix 'T', 'G', 'M', 'K', 'k' or 'b'. If it
424 does not have a suffix, it will be assumed to be in bytes. The value must be a
425 multiple of 512 bytes. It defaults to 256k.
428 Whether to verify the remote server's certificate when connecting over SSL. It
429 can have the value 'on' or 'off'. It defaults to 'on'.
432 Send this cookie (it can also be a list of cookies separated by ';') with
433 each outgoing request. Only supported when using protocols such as HTTP
434 which support cookies, otherwise ignored.
437 Set the timeout in seconds of the CURL connection. This timeout is the time
438 that CURL waits for a response from the remote server to get the size of the
439 image to be downloaded. If not set, the default timeout of 5 seconds is used.
442 Note that when passing options to qemu explicitly, @option{driver} is the value
445 Example: boot from a remote Fedora 20 live ISO image
447 @value{qemu_system_x86} --drive media=cdrom,file=http://dl.fedoraproject.org/pub/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso,readonly
449 @value{qemu_system_x86} --drive media=cdrom,file.driver=http,file.url=http://dl.fedoraproject.org/pub/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso,readonly
452 Example: boot from a remote Fedora 20 cloud image using a local overlay for
453 writes, copy-on-read, and a readahead of 64k
455 qemu-img create -f qcow2 -o backing_file='json:@{"file.driver":"http",, "file.url":"https://dl.fedoraproject.org/pub/fedora/linux/releases/20/Images/x86_64/Fedora-x86_64-20-20131211.1-sda.qcow2",, "file.readahead":"64k"@}' /tmp/Fedora-x86_64-20-20131211.1-sda.qcow2
457 @value{qemu_system_x86} -drive file=/tmp/Fedora-x86_64-20-20131211.1-sda.qcow2,copy-on-read=on
460 Example: boot from an image stored on a VMware vSphere server with a self-signed
461 certificate using a local overlay for writes, a readahead of 64k and a timeout
464 qemu-img create -f qcow2 -o backing_file='json:@{"file.driver":"https",, "file.url":"https://user:password@@vsphere.example.com/folder/test/test-flat.vmdk?dcPath=Datacenter&dsName=datastore1",, "file.sslverify":"off",, "file.readahead":"64k",, "file.timeout":10@}' /tmp/test.qcow2
466 @value{qemu_system_x86} -drive file=/tmp/test.qcow2
474 @section Keys in the graphical frontends
478 During the graphical emulation, you can use special key combinations to change
479 modes. The default key mappings are shown below, but if you use @code{-alt-grab}
480 then the modifier is Ctrl-Alt-Shift (instead of Ctrl-Alt) and if you use
481 @code{-ctrl-grab} then the modifier is the right Ctrl key (instead of Ctrl-Alt):
498 Restore the screen's un-scaled dimensions
502 Switch to virtual console 'n'. Standard console mappings are:
505 Target system display
514 Toggle mouse and keyboard grab.
520 @kindex Ctrl-PageDown
521 In the virtual consoles, you can use @key{Ctrl-Up}, @key{Ctrl-Down},
522 @key{Ctrl-PageUp} and @key{Ctrl-PageDown} to move in the back log.
527 @section Keys in the character backend multiplexer
531 During emulation, if you are using a character backend multiplexer
532 (which is the default if you are using @option{-nographic}) then
533 several commands are available via an escape sequence. These
534 key sequences all start with an escape character, which is @key{Ctrl-a}
535 by default, but can be changed with @option{-echr}. The list below assumes
536 you're using the default.
547 Save disk data back to file (if -snapshot)
550 Toggle console timestamps
553 Send break (magic sysrq in Linux)
556 Rotate between the frontends connected to the multiplexer (usually
557 this switches between the monitor and the console)
559 @kindex Ctrl-a Ctrl-a
560 Send the escape character to the frontend
567 The HTML documentation of QEMU for more precise information and Linux
568 user mode emulator invocation.
578 @section QEMU Monitor
581 The QEMU monitor is used to give complex commands to the QEMU
582 emulator. You can use it to:
587 Remove or insert removable media images
588 (such as CD-ROM or floppies).
591 Freeze/unfreeze the Virtual Machine (VM) and save or restore its state
594 @item Inspect the VM state without an external debugger.
600 The following commands are available:
602 @include qemu-monitor.texi
604 @include qemu-monitor-info.texi
606 @subsection Integer expressions
608 The monitor understands integers expressions for every integer
609 argument. You can use register names to get the value of specifics
610 CPU registers by prefixing them with @emph{$}.
615 @include docs/qemu-cpu-models.texi
620 QEMU supports many disk image formats, including growable disk images
621 (their size increase as non empty sectors are written), compressed and
622 encrypted disk images.
625 * disk_images_quickstart:: Quick start for disk image creation
626 * disk_images_snapshot_mode:: Snapshot mode
627 * vm_snapshots:: VM snapshots
628 * qemu_img_invocation:: qemu-img Invocation
629 * qemu_nbd_invocation:: qemu-nbd Invocation
630 * disk_images_formats:: Disk image file formats
631 * host_drives:: Using host drives
632 * disk_images_fat_images:: Virtual FAT disk images
633 * disk_images_nbd:: NBD access
634 * disk_images_sheepdog:: Sheepdog disk images
635 * disk_images_iscsi:: iSCSI LUNs
636 * disk_images_gluster:: GlusterFS disk images
637 * disk_images_ssh:: Secure Shell (ssh) disk images
638 * disk_images_nvme:: NVMe userspace driver
639 * disk_image_locking:: Disk image file locking
642 @node disk_images_quickstart
643 @subsection Quick start for disk image creation
645 You can create a disk image with the command:
647 qemu-img create myimage.img mysize
649 where @var{myimage.img} is the disk image filename and @var{mysize} is its
650 size in kilobytes. You can add an @code{M} suffix to give the size in
651 megabytes and a @code{G} suffix for gigabytes.
653 See @ref{qemu_img_invocation} for more information.
655 @node disk_images_snapshot_mode
656 @subsection Snapshot mode
658 If you use the option @option{-snapshot}, all disk images are
659 considered as read only. When sectors in written, they are written in
660 a temporary file created in @file{/tmp}. You can however force the
661 write back to the raw disk images by using the @code{commit} monitor
662 command (or @key{C-a s} in the serial console).
665 @subsection VM snapshots
667 VM snapshots are snapshots of the complete virtual machine including
668 CPU state, RAM, device state and the content of all the writable
669 disks. In order to use VM snapshots, you must have at least one non
670 removable and writable block device using the @code{qcow2} disk image
671 format. Normally this device is the first virtual hard drive.
673 Use the monitor command @code{savevm} to create a new VM snapshot or
674 replace an existing one. A human readable name can be assigned to each
675 snapshot in addition to its numerical ID.
677 Use @code{loadvm} to restore a VM snapshot and @code{delvm} to remove
678 a VM snapshot. @code{info snapshots} lists the available snapshots
679 with their associated information:
682 (qemu) info snapshots
683 Snapshot devices: hda
684 Snapshot list (from hda):
685 ID TAG VM SIZE DATE VM CLOCK
686 1 start 41M 2006-08-06 12:38:02 00:00:14.954
687 2 40M 2006-08-06 12:43:29 00:00:18.633
688 3 msys 40M 2006-08-06 12:44:04 00:00:23.514
691 A VM snapshot is made of a VM state info (its size is shown in
692 @code{info snapshots}) and a snapshot of every writable disk image.
693 The VM state info is stored in the first @code{qcow2} non removable
694 and writable block device. The disk image snapshots are stored in
695 every disk image. The size of a snapshot in a disk image is difficult
696 to evaluate and is not shown by @code{info snapshots} because the
697 associated disk sectors are shared among all the snapshots to save
698 disk space (otherwise each snapshot would need a full copy of all the
701 When using the (unrelated) @code{-snapshot} option
702 (@ref{disk_images_snapshot_mode}), you can always make VM snapshots,
703 but they are deleted as soon as you exit QEMU.
705 VM snapshots currently have the following known limitations:
708 They cannot cope with removable devices if they are removed or
709 inserted after a snapshot is done.
711 A few device drivers still have incomplete snapshot support so their
712 state is not saved or restored properly (in particular USB).
715 @node qemu_img_invocation
716 @subsection @code{qemu-img} Invocation
718 @include qemu-img.texi
720 @node qemu_nbd_invocation
721 @subsection @code{qemu-nbd} Invocation
723 @include qemu-nbd.texi
725 @include docs/qemu-block-drivers.texi
728 @section Network emulation
730 QEMU can simulate several network cards (e.g. PCI or ISA cards on the PC
731 target) and can connect them to a network backend on the host or an emulated
732 hub. The various host network backends can either be used to connect the NIC of
733 the guest to a real network (e.g. by using a TAP devices or the non-privileged
734 user mode network stack), or to other guest instances running in another QEMU
735 process (e.g. by using the socket host network backend).
737 @subsection Using TAP network interfaces
739 This is the standard way to connect QEMU to a real network. QEMU adds
740 a virtual network device on your host (called @code{tapN}), and you
741 can then configure it as if it was a real ethernet card.
743 @subsubsection Linux host
745 As an example, you can download the @file{linux-test-xxx.tar.gz}
746 archive and copy the script @file{qemu-ifup} in @file{/etc} and
747 configure properly @code{sudo} so that the command @code{ifconfig}
748 contained in @file{qemu-ifup} can be executed as root. You must verify
749 that your host kernel supports the TAP network interfaces: the
750 device @file{/dev/net/tun} must be present.
752 See @ref{sec_invocation} to have examples of command lines using the
753 TAP network interfaces.
755 @subsubsection Windows host
757 There is a virtual ethernet driver for Windows 2000/XP systems, called
758 TAP-Win32. But it is not included in standard QEMU for Windows,
759 so you will need to get it separately. It is part of OpenVPN package,
760 so download OpenVPN from : @url{https://openvpn.net/}.
762 @subsection Using the user mode network stack
764 By using the option @option{-net user} (default configuration if no
765 @option{-net} option is specified), QEMU uses a completely user mode
766 network stack (you don't need root privilege to use the virtual
767 network). The virtual network configuration is the following:
771 guest (10.0.2.15) <------> Firewall/DHCP server <-----> Internet
774 ----> DNS server (10.0.2.3)
776 ----> SMB server (10.0.2.4)
779 The QEMU VM behaves as if it was behind a firewall which blocks all
780 incoming connections. You can use a DHCP client to automatically
781 configure the network in the QEMU VM. The DHCP server assign addresses
782 to the hosts starting from 10.0.2.15.
784 In order to check that the user mode network is working, you can ping
785 the address 10.0.2.2 and verify that you got an address in the range
786 10.0.2.x from the QEMU virtual DHCP server.
788 Note that ICMP traffic in general does not work with user mode networking.
789 @code{ping}, aka. ICMP echo, to the local router (10.0.2.2) shall work,
790 however. If you're using QEMU on Linux >= 3.0, it can use unprivileged ICMP
791 ping sockets to allow @code{ping} to the Internet. The host admin has to set
792 the ping_group_range in order to grant access to those sockets. To allow ping
793 for GID 100 (usually users group):
796 echo 100 100 > /proc/sys/net/ipv4/ping_group_range
799 When using the built-in TFTP server, the router is also the TFTP
802 When using the @option{'-netdev user,hostfwd=...'} option, TCP or UDP
803 connections can be redirected from the host to the guest. It allows for
804 example to redirect X11, telnet or SSH connections.
808 QEMU can simulate several hubs. A hub can be thought of as a virtual connection
809 between several network devices. These devices can be for example QEMU virtual
810 ethernet cards or virtual Host ethernet devices (TAP devices). You can connect
811 guest NICs or host network backends to such a hub using the @option{-netdev
812 hubport} or @option{-nic hubport} options. The legacy @option{-net} option
813 also connects the given device to the emulated hub with ID 0 (i.e. the default
814 hub) unless you specify a netdev with @option{-net nic,netdev=xxx} here.
816 @subsection Connecting emulated networks between QEMU instances
818 Using the @option{-netdev socket} (or @option{-nic socket} or
819 @option{-net socket}) option, it is possible to create emulated
820 networks that span several QEMU instances.
821 See the description of the @option{-netdev socket} option in the
822 @ref{sec_invocation,,Invocation chapter} to have a basic example.
824 @node pcsys_other_devs
825 @section Other Devices
827 @subsection Inter-VM Shared Memory device
829 On Linux hosts, a shared memory device is available. The basic syntax
833 @value{qemu_system_x86} -device ivshmem-plain,memdev=@var{hostmem}
836 where @var{hostmem} names a host memory backend. For a POSIX shared
837 memory backend, use something like
840 -object memory-backend-file,size=1M,share,mem-path=/dev/shm/ivshmem,id=@var{hostmem}
843 If desired, interrupts can be sent between guest VMs accessing the same shared
844 memory region. Interrupt support requires using a shared memory server and
845 using a chardev socket to connect to it. The code for the shared memory server
846 is qemu.git/contrib/ivshmem-server. An example syntax when using the shared
850 # First start the ivshmem server once and for all
851 ivshmem-server -p @var{pidfile} -S @var{path} -m @var{shm-name} -l @var{shm-size} -n @var{vectors}
853 # Then start your qemu instances with matching arguments
854 @value{qemu_system_x86} -device ivshmem-doorbell,vectors=@var{vectors},chardev=@var{id}
855 -chardev socket,path=@var{path},id=@var{id}
858 When using the server, the guest will be assigned a VM ID (>=0) that allows guests
859 using the same server to communicate via interrupts. Guests can read their
860 VM ID from a device register (see ivshmem-spec.txt).
862 @subsubsection Migration with ivshmem
864 With device property @option{master=on}, the guest will copy the shared
865 memory on migration to the destination host. With @option{master=off},
866 the guest will not be able to migrate with the device attached. In the
867 latter case, the device should be detached and then reattached after
868 migration using the PCI hotplug support.
870 At most one of the devices sharing the same memory can be master. The
871 master must complete migration before you plug back the other devices.
873 @subsubsection ivshmem and hugepages
875 Instead of specifying the <shm size> using POSIX shm, you may specify
876 a memory backend that has hugepage support:
879 @value{qemu_system_x86} -object memory-backend-file,size=1G,mem-path=/dev/hugepages/my-shmem-file,share,id=mb1
880 -device ivshmem-plain,memdev=mb1
883 ivshmem-server also supports hugepages mount points with the
884 @option{-m} memory path argument.
886 @node direct_linux_boot
887 @section Direct Linux Boot
889 This section explains how to launch a Linux kernel inside QEMU without
890 having to make a full bootable image. It is very useful for fast Linux
895 @value{qemu_system} -kernel bzImage -hda rootdisk.img -append "root=/dev/hda"
898 Use @option{-kernel} to provide the Linux kernel image and
899 @option{-append} to give the kernel command line arguments. The
900 @option{-initrd} option can be used to provide an INITRD image.
902 When using the direct Linux boot, a disk image for the first hard disk
903 @file{hda} is required because its boot sector is used to launch the
906 If you do not need graphical output, you can disable it and redirect
907 the virtual serial port and the QEMU monitor to the console with the
908 @option{-nographic} option. The typical command line is:
910 @value{qemu_system} -kernel bzImage -hda rootdisk.img \
911 -append "root=/dev/hda console=ttyS0" -nographic
914 Use @key{Ctrl-a c} to switch between the serial console and the
915 monitor (@pxref{pcsys_keys}).
918 @section USB emulation
920 QEMU can emulate a PCI UHCI, OHCI, EHCI or XHCI USB controller. You can
921 plug virtual USB devices or real host USB devices (only works with certain
922 host operating systems). QEMU will automatically create and connect virtual
923 USB hubs as necessary to connect multiple USB devices.
930 @subsection Connecting USB devices
932 USB devices can be connected with the @option{-device usb-...} command line
933 option or the @code{device_add} monitor command. Available devices are:
937 Virtual Mouse. This will override the PS/2 mouse emulation when activated.
939 Pointer device that uses absolute coordinates (like a touchscreen).
940 This means QEMU is able to report the mouse position without having
941 to grab the mouse. Also overrides the PS/2 mouse emulation when activated.
942 @item usb-storage,drive=@var{drive_id}
943 Mass storage device backed by @var{drive_id} (@pxref{disk_images})
945 USB attached SCSI device, see
946 @url{https://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/usb-storage.txt,usb-storage.txt}
949 Bulk-only transport storage device, see
950 @url{https://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/usb-storage.txt,usb-storage.txt}
951 for details here, too
952 @item usb-mtp,rootdir=@var{dir}
953 Media transfer protocol device, using @var{dir} as root of the file tree
954 that is presented to the guest.
955 @item usb-host,hostbus=@var{bus},hostaddr=@var{addr}
956 Pass through the host device identified by @var{bus} and @var{addr}
957 @item usb-host,vendorid=@var{vendor},productid=@var{product}
958 Pass through the host device identified by @var{vendor} and @var{product} ID
959 @item usb-wacom-tablet
960 Virtual Wacom PenPartner tablet. This device is similar to the @code{tablet}
961 above but it can be used with the tslib library because in addition to touch
962 coordinates it reports touch pressure.
964 Standard USB keyboard. Will override the PS/2 keyboard (if present).
965 @item usb-serial,chardev=@var{id}
966 Serial converter. This emulates an FTDI FT232BM chip connected to host character
968 @item usb-braille,chardev=@var{id}
969 Braille device. This will use BrlAPI to display the braille output on a real
970 or fake device referenced by @var{id}.
971 @item usb-net[,netdev=@var{id}]
972 Network adapter that supports CDC ethernet and RNDIS protocols. @var{id}
973 specifies a netdev defined with @code{-netdev @dots{},id=@var{id}}.
974 For instance, user-mode networking can be used with
976 @value{qemu_system} [...] -netdev user,id=net0 -device usb-net,netdev=net0
979 Smartcard reader device
983 Bluetooth dongle for the transport layer of HCI. It is connected to HCI
984 scatternet 0 by default (corresponds to @code{-bt hci,vlan=0}).
985 Note that the syntax for the @code{-device usb-bt-dongle} option is not as
986 useful yet as it was with the legacy @code{-usbdevice} option. So to
987 configure an USB bluetooth device, you might need to use
988 "@code{-usbdevice bt}[:@var{hci-type}]" instead. This configures a
989 bluetooth dongle whose type is specified in the same format as with
990 the @option{-bt hci} option, @pxref{bt-hcis,,allowed HCI types}. If
991 no type is given, the HCI logic corresponds to @code{-bt hci,vlan=0}.
992 This USB device implements the USB Transport Layer of HCI. Example
995 @command{@value{qemu_system}} [...@var{OPTIONS}...] @option{-usbdevice} bt:hci,vlan=3 @option{-bt} device:keyboard,vlan=3
999 @node host_usb_devices
1000 @subsection Using host USB devices on a Linux host
1002 WARNING: this is an experimental feature. QEMU will slow down when
1003 using it. USB devices requiring real time streaming (i.e. USB Video
1004 Cameras) are not supported yet.
1007 @item If you use an early Linux 2.4 kernel, verify that no Linux driver
1008 is actually using the USB device. A simple way to do that is simply to
1009 disable the corresponding kernel module by renaming it from @file{mydriver.o}
1010 to @file{mydriver.o.disabled}.
1012 @item Verify that @file{/proc/bus/usb} is working (most Linux distributions should enable it by default). You should see something like that:
1018 @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:
1020 chown -R myuid /proc/bus/usb
1023 @item Launch QEMU and do in the monitor:
1026 Device 1.2, speed 480 Mb/s
1027 Class 00: USB device 1234:5678, USB DISK
1029 You should see the list of the devices you can use (Never try to use
1030 hubs, it won't work).
1032 @item Add the device in QEMU by using:
1034 device_add usb-host,vendorid=0x1234,productid=0x5678
1037 Normally the guest OS should report that a new USB device is plugged.
1038 You can use the option @option{-device usb-host,...} to do the same.
1040 @item Now you can try to use the host USB device in QEMU.
1044 When relaunching QEMU, you may have to unplug and plug again the USB
1045 device to make it work again (this is a bug).
1048 @section VNC security
1050 The VNC server capability provides access to the graphical console
1051 of the guest VM across the network. This has a number of security
1052 considerations depending on the deployment scenarios.
1056 * vnc_sec_password::
1057 * vnc_sec_certificate::
1058 * vnc_sec_certificate_verify::
1059 * vnc_sec_certificate_pw::
1061 * vnc_sec_certificate_sasl::
1065 @subsection Without passwords
1067 The simplest VNC server setup does not include any form of authentication.
1068 For this setup it is recommended to restrict it to listen on a UNIX domain
1069 socket only. For example
1072 @value{qemu_system} [...OPTIONS...] -vnc unix:/home/joebloggs/.qemu-myvm-vnc
1075 This ensures that only users on local box with read/write access to that
1076 path can access the VNC server. To securely access the VNC server from a
1077 remote machine, a combination of netcat+ssh can be used to provide a secure
1080 @node vnc_sec_password
1081 @subsection With passwords
1083 The VNC protocol has limited support for password based authentication. Since
1084 the protocol limits passwords to 8 characters it should not be considered
1085 to provide high security. The password can be fairly easily brute-forced by
1086 a client making repeat connections. For this reason, a VNC server using password
1087 authentication should be restricted to only listen on the loopback interface
1088 or UNIX domain sockets. Password authentication is not supported when operating
1089 in FIPS 140-2 compliance mode as it requires the use of the DES cipher. Password
1090 authentication is requested with the @code{password} option, and then once QEMU
1091 is running the password is set with the monitor. Until the monitor is used to
1092 set the password all clients will be rejected.
1095 @value{qemu_system} [...OPTIONS...] -vnc :1,password -monitor stdio
1096 (qemu) change vnc password
1101 @node vnc_sec_certificate
1102 @subsection With x509 certificates
1104 The QEMU VNC server also implements the VeNCrypt extension allowing use of
1105 TLS for encryption of the session, and x509 certificates for authentication.
1106 The use of x509 certificates is strongly recommended, because TLS on its
1107 own is susceptible to man-in-the-middle attacks. Basic x509 certificate
1108 support provides a secure session, but no authentication. This allows any
1109 client to connect, and provides an encrypted session.
1112 @value{qemu_system} [...OPTIONS...] \
1113 -object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server,verify-peer=no \
1114 -vnc :1,tls-creds=tls0 -monitor stdio
1117 In the above example @code{/etc/pki/qemu} should contain at least three files,
1118 @code{ca-cert.pem}, @code{server-cert.pem} and @code{server-key.pem}. Unprivileged
1119 users will want to use a private directory, for example @code{$HOME/.pki/qemu}.
1120 NB the @code{server-key.pem} file should be protected with file mode 0600 to
1121 only be readable by the user owning it.
1123 @node vnc_sec_certificate_verify
1124 @subsection With x509 certificates and client verification
1126 Certificates can also provide a means to authenticate the client connecting.
1127 The server will request that the client provide a certificate, which it will
1128 then validate against the CA certificate. This is a good choice if deploying
1129 in an environment with a private internal certificate authority. It uses the
1130 same syntax as previously, but with @code{verify-peer} set to @code{yes}
1134 @value{qemu_system} [...OPTIONS...] \
1135 -object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server,verify-peer=yes \
1136 -vnc :1,tls-creds=tls0 -monitor stdio
1140 @node vnc_sec_certificate_pw
1141 @subsection With x509 certificates, client verification and passwords
1143 Finally, the previous method can be combined with VNC password authentication
1144 to provide two layers of authentication for clients.
1147 @value{qemu_system} [...OPTIONS...] \
1148 -object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server,verify-peer=yes \
1149 -vnc :1,tls-creds=tls0,password -monitor stdio
1150 (qemu) change vnc password
1157 @subsection With SASL authentication
1159 The SASL authentication method is a VNC extension, that provides an
1160 easily extendable, pluggable authentication method. This allows for
1161 integration with a wide range of authentication mechanisms, such as
1162 PAM, GSSAPI/Kerberos, LDAP, SQL databases, one-time keys and more.
1163 The strength of the authentication depends on the exact mechanism
1164 configured. If the chosen mechanism also provides a SSF layer, then
1165 it will encrypt the datastream as well.
1167 Refer to the later docs on how to choose the exact SASL mechanism
1168 used for authentication, but assuming use of one supporting SSF,
1169 then QEMU can be launched with:
1172 @value{qemu_system} [...OPTIONS...] -vnc :1,sasl -monitor stdio
1175 @node vnc_sec_certificate_sasl
1176 @subsection With x509 certificates and SASL authentication
1178 If the desired SASL authentication mechanism does not supported
1179 SSF layers, then it is strongly advised to run it in combination
1180 with TLS and x509 certificates. This provides securely encrypted
1181 data stream, avoiding risk of compromising of the security
1182 credentials. This can be enabled, by combining the 'sasl' option
1183 with the aforementioned TLS + x509 options:
1186 @value{qemu_system} [...OPTIONS...] \
1187 -object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server,verify-peer=yes \
1188 -vnc :1,tls-creds=tls0,sasl -monitor stdio
1191 @node vnc_setup_sasl
1193 @subsection Configuring SASL mechanisms
1195 The following documentation assumes use of the Cyrus SASL implementation on a
1196 Linux host, but the principles should apply to any other SASL implementation
1197 or host. When SASL is enabled, the mechanism configuration will be loaded from
1198 system default SASL service config /etc/sasl2/qemu.conf. If running QEMU as an
1199 unprivileged user, an environment variable SASL_CONF_PATH can be used to make
1200 it search alternate locations for the service config file.
1202 If the TLS option is enabled for VNC, then it will provide session encryption,
1203 otherwise the SASL mechanism will have to provide encryption. In the latter
1204 case the list of possible plugins that can be used is drastically reduced. In
1205 fact only the GSSAPI SASL mechanism provides an acceptable level of security
1206 by modern standards. Previous versions of QEMU referred to the DIGEST-MD5
1207 mechanism, however, it has multiple serious flaws described in detail in
1208 RFC 6331 and thus should never be used any more. The SCRAM-SHA-1 mechanism
1209 provides a simple username/password auth facility similar to DIGEST-MD5, but
1210 does not support session encryption, so can only be used in combination with
1213 When not using TLS the recommended configuration is
1217 keytab: /etc/qemu/krb5.tab
1220 This says to use the 'GSSAPI' mechanism with the Kerberos v5 protocol, with
1221 the server principal stored in /etc/qemu/krb5.tab. For this to work the
1222 administrator of your KDC must generate a Kerberos principal for the server,
1223 with a name of 'qemu/somehost.example.com@@EXAMPLE.COM' replacing
1224 'somehost.example.com' with the fully qualified host name of the machine
1225 running QEMU, and 'EXAMPLE.COM' with the Kerberos Realm.
1227 When using TLS, if username+password authentication is desired, then a
1228 reasonable configuration is
1231 mech_list: scram-sha-1
1232 sasldb_path: /etc/qemu/passwd.db
1235 The @code{saslpasswd2} program can be used to populate the @code{passwd.db}
1238 Other SASL configurations will be left as an exercise for the reader. Note that
1239 all mechanisms, except GSSAPI, should be combined with use of TLS to ensure a
1240 secure data channel.
1244 @section TLS setup for network services
1246 Almost all network services in QEMU have the ability to use TLS for
1247 session data encryption, along with x509 certificates for simple
1248 client authentication. What follows is a description of how to
1249 generate certificates suitable for usage with QEMU, and applies to
1250 the VNC server, character devices with the TCP backend, NBD server
1251 and client, and migration server and client.
1253 At a high level, QEMU requires certificates and private keys to be
1254 provided in PEM format. Aside from the core fields, the certificates
1255 should include various extension data sets, including v3 basic
1256 constraints data, key purpose, key usage and subject alt name.
1258 The GnuTLS package includes a command called @code{certtool} which can
1259 be used to easily generate certificates and keys in the required format
1260 with expected data present. Alternatively a certificate management
1261 service may be used.
1263 At a minimum it is necessary to setup a certificate authority, and
1264 issue certificates to each server. If using x509 certificates for
1265 authentication, then each client will also need to be issued a
1268 Assuming that the QEMU network services will only ever be exposed to
1269 clients on a private intranet, there is no need to use a commercial
1270 certificate authority to create certificates. A self-signed CA is
1271 sufficient, and in fact likely to be more secure since it removes
1272 the ability of malicious 3rd parties to trick the CA into mis-issuing
1273 certs for impersonating your services. The only likely exception
1274 where a commercial CA might be desirable is if enabling the VNC
1275 websockets server and exposing it directly to remote browser clients.
1276 In such a case it might be useful to use a commercial CA to avoid
1277 needing to install custom CA certs in the web browsers.
1279 The recommendation is for the server to keep its certificates in either
1280 @code{/etc/pki/qemu} or for unprivileged users in @code{$HOME/.pki/qemu}.
1284 * tls_generate_server::
1285 * tls_generate_client::
1289 @node tls_generate_ca
1290 @subsection Setup the Certificate Authority
1292 This step only needs to be performed once per organization / organizational
1293 unit. First the CA needs a private key. This key must be kept VERY secret
1294 and secure. If this key is compromised the entire trust chain of the certificates
1295 issued with it is lost.
1298 # certtool --generate-privkey > ca-key.pem
1301 To generate a self-signed certificate requires one core piece of information,
1302 the name of the organization. A template file @code{ca.info} should be
1303 populated with the desired data to avoid having to deal with interactive
1304 prompts from certtool:
1306 # cat > ca.info <<EOF
1307 cn = Name of your organization
1311 # certtool --generate-self-signed \
1312 --load-privkey ca-key.pem
1313 --template ca.info \
1314 --outfile ca-cert.pem
1317 The @code{ca} keyword in the template sets the v3 basic constraints extension
1318 to indicate this certificate is for a CA, while @code{cert_signing_key} sets
1319 the key usage extension to indicate this will be used for signing other keys.
1320 The generated @code{ca-cert.pem} file should be copied to all servers and
1321 clients wishing to utilize TLS support in the VNC server. The @code{ca-key.pem}
1322 must not be disclosed/copied anywhere except the host responsible for issuing
1325 @node tls_generate_server
1326 @subsection Issuing server certificates
1328 Each server (or host) needs to be issued with a key and certificate. When connecting
1329 the certificate is sent to the client which validates it against the CA certificate.
1330 The core pieces of information for a server certificate are the hostnames and/or IP
1331 addresses that will be used by clients when connecting. The hostname / IP address
1332 that the client specifies when connecting will be validated against the hostname(s)
1333 and IP address(es) recorded in the server certificate, and if no match is found
1334 the client will close the connection.
1336 Thus it is recommended that the server certificate include both the fully qualified
1337 and unqualified hostnames. If the server will have permanently assigned IP address(es),
1338 and clients are likely to use them when connecting, they may also be included in the
1339 certificate. Both IPv4 and IPv6 addresses are supported. Historically certificates
1340 only included 1 hostname in the @code{CN} field, however, usage of this field for
1341 validation is now deprecated. Instead modern TLS clients will validate against the
1342 Subject Alt Name extension data, which allows for multiple entries. In the future
1343 usage of the @code{CN} field may be discontinued entirely, so providing SAN
1344 extension data is strongly recommended.
1346 On the host holding the CA, create template files containing the information
1347 for each server, and use it to issue server certificates.
1350 # cat > server-hostNNN.info <<EOF
1351 organization = Name of your organization
1352 cn = hostNNN.foo.example.com
1354 dns_name = hostNNN.foo.example.com
1355 ip_address = 10.0.1.87
1356 ip_address = 192.8.0.92
1357 ip_address = 2620:0:cafe::87
1358 ip_address = 2001:24::92
1363 # certtool --generate-privkey > server-hostNNN-key.pem
1364 # certtool --generate-certificate \
1365 --load-ca-certificate ca-cert.pem \
1366 --load-ca-privkey ca-key.pem \
1367 --load-privkey server-hostNNN-key.pem \
1368 --template server-hostNNN.info \
1369 --outfile server-hostNNN-cert.pem
1372 The @code{dns_name} and @code{ip_address} fields in the template are setting
1373 the subject alt name extension data. The @code{tls_www_server} keyword is the
1374 key purpose extension to indicate this certificate is intended for usage in
1375 a web server. Although QEMU network services are not in fact HTTP servers
1376 (except for VNC websockets), setting this key purpose is still recommended.
1377 The @code{encryption_key} and @code{signing_key} keyword is the key usage
1378 extension to indicate this certificate is intended for usage in the data
1381 The @code{server-hostNNN-key.pem} and @code{server-hostNNN-cert.pem} files
1382 should now be securely copied to the server for which they were generated,
1383 and renamed to @code{server-key.pem} and @code{server-cert.pem} when added
1384 to the @code{/etc/pki/qemu} directory on the target host. The @code{server-key.pem}
1385 file is security sensitive and should be kept protected with file mode 0600
1386 to prevent disclosure.
1388 @node tls_generate_client
1389 @subsection Issuing client certificates
1391 The QEMU x509 TLS credential setup defaults to enabling client verification
1392 using certificates, providing a simple authentication mechanism. If this
1393 default is used, each client also needs to be issued a certificate. The client
1394 certificate contains enough metadata to uniquely identify the client with the
1395 scope of the certificate authority. The client certificate would typically
1396 include fields for organization, state, city, building, etc.
1398 Once again on the host holding the CA, create template files containing the
1399 information for each client, and use it to issue client certificates.
1403 # cat > client-hostNNN.info <<EOF
1406 locality = City Of London
1407 organization = Name of your organization
1408 cn = hostNNN.foo.example.com
1413 # certtool --generate-privkey > client-hostNNN-key.pem
1414 # certtool --generate-certificate \
1415 --load-ca-certificate ca-cert.pem \
1416 --load-ca-privkey ca-key.pem \
1417 --load-privkey client-hostNNN-key.pem \
1418 --template client-hostNNN.info \
1419 --outfile client-hostNNN-cert.pem
1422 The subject alt name extension data is not required for clients, so the
1423 the @code{dns_name} and @code{ip_address} fields are not included.
1424 The @code{tls_www_client} keyword is the key purpose extension to indicate
1425 this certificate is intended for usage in a web client. Although QEMU
1426 network clients are not in fact HTTP clients, setting this key purpose is
1427 still recommended. The @code{encryption_key} and @code{signing_key} keyword
1428 is the key usage extension to indicate this certificate is intended for
1429 usage in the data session.
1431 The @code{client-hostNNN-key.pem} and @code{client-hostNNN-cert.pem} files
1432 should now be securely copied to the client for which they were generated,
1433 and renamed to @code{client-key.pem} and @code{client-cert.pem} when added
1434 to the @code{/etc/pki/qemu} directory on the target host. The @code{client-key.pem}
1435 file is security sensitive and should be kept protected with file mode 0600
1436 to prevent disclosure.
1438 If a single host is going to be using TLS in both a client and server
1439 role, it is possible to create a single certificate to cover both roles.
1440 This would be quite common for the migration and NBD services, where a
1441 QEMU process will be started by accepting a TLS protected incoming migration,
1442 and later itself be migrated out to another host. To generate a single
1443 certificate, simply include the template data from both the client and server
1444 instructions in one.
1447 # cat > both-hostNNN.info <<EOF
1450 locality = City Of London
1451 organization = Name of your organization
1452 cn = hostNNN.foo.example.com
1454 dns_name = hostNNN.foo.example.com
1455 ip_address = 10.0.1.87
1456 ip_address = 192.8.0.92
1457 ip_address = 2620:0:cafe::87
1458 ip_address = 2001:24::92
1464 # certtool --generate-privkey > both-hostNNN-key.pem
1465 # certtool --generate-certificate \
1466 --load-ca-certificate ca-cert.pem \
1467 --load-ca-privkey ca-key.pem \
1468 --load-privkey both-hostNNN-key.pem \
1469 --template both-hostNNN.info \
1470 --outfile both-hostNNN-cert.pem
1473 When copying the PEM files to the target host, save them twice,
1474 once as @code{server-cert.pem} and @code{server-key.pem}, and
1475 again as @code{client-cert.pem} and @code{client-key.pem}.
1477 @node tls_creds_setup
1478 @subsection TLS x509 credential configuration
1480 QEMU has a standard mechanism for loading x509 credentials that will be
1481 used for network services and clients. It requires specifying the
1482 @code{tls-creds-x509} class name to the @code{--object} command line
1483 argument for the system emulators. Each set of credentials loaded should
1484 be given a unique string identifier via the @code{id} parameter. A single
1485 set of TLS credentials can be used for multiple network backends, so VNC,
1486 migration, NBD, character devices can all share the same credentials. Note,
1487 however, that credentials for use in a client endpoint must be loaded
1488 separately from those used in a server endpoint.
1490 When specifying the object, the @code{dir} parameters specifies which
1491 directory contains the credential files. This directory is expected to
1492 contain files with the names mentioned previously, @code{ca-cert.pem},
1493 @code{server-key.pem}, @code{server-cert.pem}, @code{client-key.pem}
1494 and @code{client-cert.pem} as appropriate. It is also possible to
1495 include a set of pre-generated Diffie-Hellman (DH) parameters in a file
1496 @code{dh-params.pem}, which can be created using the
1497 @code{certtool --generate-dh-params} command. If omitted, QEMU will
1498 dynamically generate DH parameters when loading the credentials.
1500 The @code{endpoint} parameter indicates whether the credentials will
1501 be used for a network client or server, and determines which PEM
1504 The @code{verify} parameter determines whether x509 certificate
1505 validation should be performed. This defaults to enabled, meaning
1506 clients will always validate the server hostname against the
1507 certificate subject alt name fields and/or CN field. It also
1508 means that servers will request that clients provide a certificate
1509 and validate them. Verification should never be turned off for
1510 client endpoints, however, it may be turned off for server endpoints
1511 if an alternative mechanism is used to authenticate clients. For
1512 example, the VNC server can use SASL to authenticate clients
1515 To load server credentials with client certificate validation
1519 @value{qemu_system} -object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server
1522 while to load client credentials use
1525 @value{qemu_system} -object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=client
1528 Network services which support TLS will all have a @code{tls-creds}
1529 parameter which expects the ID of the TLS credentials object. For
1533 @value{qemu_system} -vnc 0.0.0.0:0,tls-creds=tls0
1537 @subsection TLS Pre-Shared Keys (PSK)
1539 Instead of using certificates, you may also use TLS Pre-Shared Keys
1540 (TLS-PSK). This can be simpler to set up than certificates but is
1543 Use the GnuTLS @code{psktool} program to generate a @code{keys.psk}
1544 file containing one or more usernames and random keys:
1547 mkdir -m 0700 /tmp/keys
1548 psktool -u rich -p /tmp/keys/keys.psk
1551 TLS-enabled servers such as qemu-nbd can use this directory like so:
1556 --object tls-creds-psk,id=tls0,endpoint=server,dir=/tmp/keys \
1561 When connecting from a qemu-based client you must specify the
1562 directory containing @code{keys.psk} and an optional @var{username}
1563 (defaults to ``qemu''):
1567 --object tls-creds-psk,id=tls0,dir=/tmp/keys,username=rich,endpoint=client \
1569 file.driver=nbd,file.host=localhost,file.port=10809,file.tls-creds=tls0,file.export=/
1575 QEMU has a primitive support to work with gdb, so that you can do
1576 'Ctrl-C' while the virtual machine is running and inspect its state.
1578 In order to use gdb, launch QEMU with the '-s' option. It will wait for a
1581 @value{qemu_system} -s -kernel bzImage -hda rootdisk.img -append "root=/dev/hda"
1582 Connected to host network interface: tun0
1583 Waiting gdb connection on port 1234
1586 Then launch gdb on the 'vmlinux' executable:
1591 In gdb, connect to QEMU:
1593 (gdb) target remote localhost:1234
1596 Then you can use gdb normally. For example, type 'c' to launch the kernel:
1601 Here are some useful tips in order to use gdb on system code:
1605 Use @code{info reg} to display all the CPU registers.
1607 Use @code{x/10i $eip} to display the code at the PC position.
1609 Use @code{set architecture i8086} to dump 16 bit code. Then use
1610 @code{x/10i $cs*16+$eip} to dump the code at the PC position.
1613 Advanced debugging options:
1615 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:
1617 @item maintenance packet qqemu.sstepbits
1619 This will display the MASK bits used to control the single stepping IE:
1621 (gdb) maintenance packet qqemu.sstepbits
1622 sending: "qqemu.sstepbits"
1623 received: "ENABLE=1,NOIRQ=2,NOTIMER=4"
1625 @item maintenance packet qqemu.sstep
1627 This will display the current value of the mask used when single stepping IE:
1629 (gdb) maintenance packet qqemu.sstep
1630 sending: "qqemu.sstep"
1633 @item maintenance packet Qqemu.sstep=HEX_VALUE
1635 This will change the single step mask, so if wanted to enable IRQs on the single step, but not timers, you would use:
1637 (gdb) maintenance packet Qqemu.sstep=0x5
1638 sending: "qemu.sstep=0x5"
1643 @node pcsys_os_specific
1644 @section Target OS specific information
1648 To have access to SVGA graphic modes under X11, use the @code{vesa} or
1649 the @code{cirrus} X11 driver. For optimal performances, use 16 bit
1650 color depth in the guest and the host OS.
1652 When using a 2.6 guest Linux kernel, you should add the option
1653 @code{clock=pit} on the kernel command line because the 2.6 Linux
1654 kernels make very strict real time clock checks by default that QEMU
1655 cannot simulate exactly.
1657 When using a 2.6 guest Linux kernel, verify that the 4G/4G patch is
1658 not activated because QEMU is slower with this patch. The QEMU
1659 Accelerator Module is also much slower in this case. Earlier Fedora
1660 Core 3 Linux kernel (< 2.6.9-1.724_FC3) were known to incorporate this
1661 patch by default. Newer kernels don't have it.
1665 If you have a slow host, using Windows 95 is better as it gives the
1666 best speed. Windows 2000 is also a good choice.
1668 @subsubsection SVGA graphic modes support
1670 QEMU emulates a Cirrus Logic GD5446 Video
1671 card. All Windows versions starting from Windows 95 should recognize
1672 and use this graphic card. For optimal performances, use 16 bit color
1673 depth in the guest and the host OS.
1675 If you are using Windows XP as guest OS and if you want to use high
1676 resolution modes which the Cirrus Logic BIOS does not support (i.e. >=
1677 1280x1024x16), then you should use the VESA VBE virtual graphic card
1678 (option @option{-std-vga}).
1680 @subsubsection CPU usage reduction
1682 Windows 9x does not correctly use the CPU HLT
1683 instruction. The result is that it takes host CPU cycles even when
1684 idle. You can install the utility from
1685 @url{https://web.archive.org/web/20060212132151/http://www.user.cityline.ru/~maxamn/amnhltm.zip}
1686 to solve this problem. Note that no such tool is needed for NT, 2000 or XP.
1688 @subsubsection Windows 2000 disk full problem
1690 Windows 2000 has a bug which gives a disk full problem during its
1691 installation. When installing it, use the @option{-win2k-hack} QEMU
1692 option to enable a specific workaround. After Windows 2000 is
1693 installed, you no longer need this option (this option slows down the
1696 @subsubsection Windows 2000 shutdown
1698 Windows 2000 cannot automatically shutdown in QEMU although Windows 98
1699 can. It comes from the fact that Windows 2000 does not automatically
1700 use the APM driver provided by the BIOS.
1702 In order to correct that, do the following (thanks to Struan
1703 Bartlett): go to the Control Panel => Add/Remove Hardware & Next =>
1704 Add/Troubleshoot a device => Add a new device & Next => No, select the
1705 hardware from a list & Next => NT Apm/Legacy Support & Next => Next
1706 (again) a few times. Now the driver is installed and Windows 2000 now
1707 correctly instructs QEMU to shutdown at the appropriate moment.
1709 @subsubsection Share a directory between Unix and Windows
1711 See @ref{sec_invocation} about the help of the option
1712 @option{'-netdev user,smb=...'}.
1714 @subsubsection Windows XP security problem
1716 Some releases of Windows XP install correctly but give a security
1719 A problem is preventing Windows from accurately checking the
1720 license for this computer. Error code: 0x800703e6.
1723 The workaround is to install a service pack for XP after a boot in safe
1724 mode. Then reboot, and the problem should go away. Since there is no
1725 network while in safe mode, its recommended to download the full
1726 installation of SP1 or SP2 and transfer that via an ISO or using the
1727 vvfat block device ("-hdb fat:directory_which_holds_the_SP").
1729 @subsection MS-DOS and FreeDOS
1731 @subsubsection CPU usage reduction
1733 DOS does not correctly use the CPU HLT instruction. The result is that
1734 it takes host CPU cycles even when idle. You can install the utility from
1735 @url{https://web.archive.org/web/20051222085335/http://www.vmware.com/software/dosidle210.zip}
1736 to solve this problem.
1738 @node QEMU System emulator for non PC targets
1739 @chapter QEMU System emulator for non PC targets
1741 QEMU is a generic emulator and it emulates many non PC
1742 machines. Most of the options are similar to the PC emulator. The
1743 differences are mentioned in the following sections.
1746 * PowerPC System emulator::
1747 * Sparc32 System emulator::
1748 * Sparc64 System emulator::
1749 * MIPS System emulator::
1750 * ARM System emulator::
1751 * ColdFire System emulator::
1752 * Cris System emulator::
1753 * Microblaze System emulator::
1754 * SH4 System emulator::
1755 * Xtensa System emulator::
1758 @node PowerPC System emulator
1759 @section PowerPC System emulator
1760 @cindex system emulation (PowerPC)
1762 Use the executable @file{qemu-system-ppc} to simulate a complete PREP
1763 or PowerMac PowerPC system.
1765 QEMU emulates the following PowerMac peripherals:
1769 UniNorth or Grackle PCI Bridge
1771 PCI VGA compatible card with VESA Bochs Extensions
1773 2 PMAC IDE interfaces with hard disk and CD-ROM support
1779 VIA-CUDA with ADB keyboard and mouse.
1782 QEMU emulates the following PREP peripherals:
1788 PCI VGA compatible card with VESA Bochs Extensions
1790 2 IDE interfaces with hard disk and CD-ROM support
1794 NE2000 network adapters
1798 PREP Non Volatile RAM
1800 PC compatible keyboard and mouse.
1803 QEMU uses the Open Hack'Ware Open Firmware Compatible BIOS available at
1804 @url{http://perso.magic.fr/l_indien/OpenHackWare/index.htm}.
1806 Since version 0.9.1, QEMU uses OpenBIOS @url{https://www.openbios.org/}
1807 for the g3beige and mac99 PowerMac machines. OpenBIOS is a free (GPL
1808 v2) portable firmware implementation. The goal is to implement a 100%
1809 IEEE 1275-1994 (referred to as Open Firmware) compliant firmware.
1811 @c man begin OPTIONS
1813 The following options are specific to the PowerPC emulation:
1817 @item -g @var{W}x@var{H}[x@var{DEPTH}]
1819 Set the initial VGA graphic mode. The default is 800x600x32.
1821 @item -prom-env @var{string}
1823 Set OpenBIOS variables in NVRAM, for example:
1826 qemu-system-ppc -prom-env 'auto-boot?=false' \
1827 -prom-env 'boot-device=hd:2,\yaboot' \
1828 -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
1831 These variables are not used by Open Hack'Ware.
1838 More information is available at
1839 @url{http://perso.magic.fr/l_indien/qemu-ppc/}.
1841 @node Sparc32 System emulator
1842 @section Sparc32 System emulator
1843 @cindex system emulation (Sparc32)
1845 Use the executable @file{qemu-system-sparc} to simulate the following
1846 Sun4m architecture machines:
1861 SPARCstation Voyager
1868 The emulation is somewhat complete. SMP up to 16 CPUs is supported,
1869 but Linux limits the number of usable CPUs to 4.
1871 QEMU emulates the following sun4m peripherals:
1877 TCX or cgthree Frame buffer
1879 Lance (Am7990) Ethernet
1881 Non Volatile RAM M48T02/M48T08
1883 Slave I/O: timers, interrupt controllers, Zilog serial ports, keyboard
1884 and power/reset logic
1886 ESP SCSI controller with hard disk and CD-ROM support
1888 Floppy drive (not on SS-600MP)
1890 CS4231 sound device (only on SS-5, not working yet)
1893 The number of peripherals is fixed in the architecture. Maximum
1894 memory size depends on the machine type, for SS-5 it is 256MB and for
1897 Since version 0.8.2, QEMU uses OpenBIOS
1898 @url{https://www.openbios.org/}. OpenBIOS is a free (GPL v2) portable
1899 firmware implementation. The goal is to implement a 100% IEEE
1900 1275-1994 (referred to as Open Firmware) compliant firmware.
1902 A sample Linux 2.6 series kernel and ram disk image are available on
1903 the QEMU web site. There are still issues with NetBSD and OpenBSD, but
1904 most kernel versions work. Please note that currently older Solaris kernels
1905 don't work probably due to interface issues between OpenBIOS and
1908 @c man begin OPTIONS
1910 The following options are specific to the Sparc32 emulation:
1914 @item -g @var{W}x@var{H}x[x@var{DEPTH}]
1916 Set the initial graphics mode. For TCX, the default is 1024x768x8 with the
1917 option of 1024x768x24. For cgthree, the default is 1024x768x8 with the option
1918 of 1152x900x8 for people who wish to use OBP.
1920 @item -prom-env @var{string}
1922 Set OpenBIOS variables in NVRAM, for example:
1925 qemu-system-sparc -prom-env 'auto-boot?=false' \
1926 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
1929 @item -M [SS-4|SS-5|SS-10|SS-20|SS-600MP|LX|Voyager|SPARCClassic] [|SPARCbook]
1931 Set the emulated machine type. Default is SS-5.
1937 @node Sparc64 System emulator
1938 @section Sparc64 System emulator
1939 @cindex system emulation (Sparc64)
1941 Use the executable @file{qemu-system-sparc64} to simulate a Sun4u
1942 (UltraSPARC PC-like machine), Sun4v (T1 PC-like machine), or generic
1943 Niagara (T1) machine. The Sun4u emulator is mostly complete, being
1944 able to run Linux, NetBSD and OpenBSD in headless (-nographic) mode. The
1945 Sun4v emulator is still a work in progress.
1947 The Niagara T1 emulator makes use of firmware and OS binaries supplied in the S10image/ directory
1948 of the OpenSPARC T1 project @url{http://download.oracle.com/technetwork/systems/opensparc/OpenSPARCT1_Arch.1.5.tar.bz2}
1949 and is able to boot the disk.s10hw2 Solaris image.
1951 qemu-system-sparc64 -M niagara -L /path-to/S10image/ \
1953 -drive if=pflash,readonly=on,file=/S10image/disk.s10hw2
1957 QEMU emulates the following peripherals:
1961 UltraSparc IIi APB PCI Bridge
1963 PCI VGA compatible card with VESA Bochs Extensions
1965 PS/2 mouse and keyboard
1967 Non Volatile RAM M48T59
1969 PC-compatible serial ports
1971 2 PCI IDE interfaces with hard disk and CD-ROM support
1976 @c man begin OPTIONS
1978 The following options are specific to the Sparc64 emulation:
1982 @item -prom-env @var{string}
1984 Set OpenBIOS variables in NVRAM, for example:
1987 qemu-system-sparc64 -prom-env 'auto-boot?=false'
1990 @item -M [sun4u|sun4v|niagara]
1992 Set the emulated machine type. The default is sun4u.
1998 @node MIPS System emulator
1999 @section MIPS System emulator
2000 @cindex system emulation (MIPS)
2003 * nanoMIPS System emulator ::
2006 Four executables cover simulation of 32 and 64-bit MIPS systems in
2007 both endian options, @file{qemu-system-mips}, @file{qemu-system-mipsel}
2008 @file{qemu-system-mips64} and @file{qemu-system-mips64el}.
2009 Five different machine types are emulated:
2013 A generic ISA PC-like machine "mips"
2015 The MIPS Malta prototype board "malta"
2017 An ACER Pica "pica61". This machine needs the 64-bit emulator.
2019 MIPS emulator pseudo board "mipssim"
2021 A MIPS Magnum R4000 machine "magnum". This machine needs the 64-bit emulator.
2024 The generic emulation is supported by Debian 'Etch' and is able to
2025 install Debian into a virtual disk image. The following devices are
2030 A range of MIPS CPUs, default is the 24Kf
2032 PC style serial port
2039 The Malta emulation supports the following devices:
2043 Core board with MIPS 24Kf CPU and Galileo system controller
2045 PIIX4 PCI/USB/SMbus controller
2047 The Multi-I/O chip's serial device
2049 PCI network cards (PCnet32 and others)
2051 Malta FPGA serial device
2053 Cirrus (default) or any other PCI VGA graphics card
2056 The Boston board emulation supports the following devices:
2060 Xilinx FPGA, which includes a PCIe root port and an UART
2062 Intel EG20T PCH connects the I/O peripherals, but only the SATA bus is emulated
2065 The ACER Pica emulation supports:
2071 PC-style IRQ and DMA controllers
2078 The MIPS Magnum R4000 emulation supports:
2084 PC-style IRQ controller
2093 The Fulong 2E emulation supports:
2099 Bonito64 system controller as North Bridge
2101 VT82C686 chipset as South Bridge
2103 RTL8139D as a network card chipset
2106 The mipssim pseudo board emulation provides an environment similar
2107 to what the proprietary MIPS emulator uses for running Linux.
2112 A range of MIPS CPUs, default is the 24Kf
2114 PC style serial port
2116 MIPSnet network emulation
2119 @node nanoMIPS System emulator
2120 @subsection nanoMIPS System emulator
2121 @cindex system emulation (nanoMIPS)
2123 Executable @file{qemu-system-mipsel} also covers simulation of
2124 32-bit nanoMIPS system in little endian mode:
2131 Example of @file{qemu-system-mipsel} usage for nanoMIPS is shown below:
2133 Download @code{<disk_image_file>} from @url{https://mipsdistros.mips.com/LinuxDistro/nanomips/buildroot/index.html}.
2135 Download @code{<kernel_image_file>} from @url{https://mipsdistros.mips.com/LinuxDistro/nanomips/kernels/v4.15.18-432-gb2eb9a8b07a1-20180627102142/index.html}.
2137 Start system emulation of Malta board with nanoMIPS I7200 CPU:
2139 qemu-system-mipsel -cpu I7200 -kernel @code{<kernel_image_file>} \
2140 -M malta -serial stdio -m @code{<memory_size>} -hda @code{<disk_image_file>} \
2141 -append "mem=256m@@0x0 rw console=ttyS0 vga=cirrus vesa=0x111 root=/dev/sda"
2145 @node ARM System emulator
2146 @section ARM System emulator
2147 @cindex system emulation (ARM)
2149 Use the executable @file{qemu-system-arm} to simulate a ARM
2150 machine. The ARM Integrator/CP board is emulated with the following
2155 ARM926E, ARM1026E, ARM946E, ARM1136 or Cortex-A8 CPU
2159 SMC 91c111 Ethernet adapter
2161 PL110 LCD controller
2163 PL050 KMI with PS/2 keyboard and mouse.
2165 PL181 MultiMedia Card Interface with SD card.
2168 The ARM Versatile baseboard is emulated with the following devices:
2172 ARM926E, ARM1136 or Cortex-A8 CPU
2174 PL190 Vectored Interrupt Controller
2178 SMC 91c111 Ethernet adapter
2180 PL110 LCD controller
2182 PL050 KMI with PS/2 keyboard and mouse.
2184 PCI host bridge. Note the emulated PCI bridge only provides access to
2185 PCI memory space. It does not provide access to PCI IO space.
2186 This means some devices (eg. ne2k_pci NIC) are not usable, and others
2187 (eg. rtl8139 NIC) are only usable when the guest drivers use the memory
2188 mapped control registers.
2190 PCI OHCI USB controller.
2192 LSI53C895A PCI SCSI Host Bus Adapter with hard disk and CD-ROM devices.
2194 PL181 MultiMedia Card Interface with SD card.
2197 Several variants of the ARM RealView baseboard are emulated,
2198 including the EB, PB-A8 and PBX-A9. Due to interactions with the
2199 bootloader, only certain Linux kernel configurations work out
2200 of the box on these boards.
2202 Kernels for the PB-A8 board should have CONFIG_REALVIEW_HIGH_PHYS_OFFSET
2203 enabled in the kernel, and expect 512M RAM. Kernels for The PBX-A9 board
2204 should have CONFIG_SPARSEMEM enabled, CONFIG_REALVIEW_HIGH_PHYS_OFFSET
2205 disabled and expect 1024M RAM.
2207 The following devices are emulated:
2211 ARM926E, ARM1136, ARM11MPCore, Cortex-A8 or Cortex-A9 MPCore CPU
2213 ARM AMBA Generic/Distributed Interrupt Controller
2217 SMC 91c111 or SMSC LAN9118 Ethernet adapter
2219 PL110 LCD controller
2221 PL050 KMI with PS/2 keyboard and mouse
2225 PCI OHCI USB controller
2227 LSI53C895A PCI SCSI Host Bus Adapter with hard disk and CD-ROM devices
2229 PL181 MultiMedia Card Interface with SD card.
2232 The XScale-based clamshell PDA models ("Spitz", "Akita", "Borzoi"
2233 and "Terrier") emulation includes the following peripherals:
2237 Intel PXA270 System-on-chip (ARM V5TE core)
2241 IBM/Hitachi DSCM microdrive in a PXA PCMCIA slot - not in "Akita"
2243 On-chip OHCI USB controller
2245 On-chip LCD controller
2247 On-chip Real Time Clock
2249 TI ADS7846 touchscreen controller on SSP bus
2251 Maxim MAX1111 analog-digital converter on I@math{^2}C bus
2253 GPIO-connected keyboard controller and LEDs
2255 Secure Digital card connected to PXA MMC/SD host
2259 WM8750 audio CODEC on I@math{^2}C and I@math{^2}S busses
2262 The Palm Tungsten|E PDA (codename "Cheetah") emulation includes the
2267 Texas Instruments OMAP310 System-on-chip (ARM 925T core)
2269 ROM and RAM memories (ROM firmware image can be loaded with -option-rom)
2271 On-chip LCD controller
2273 On-chip Real Time Clock
2275 TI TSC2102i touchscreen controller / analog-digital converter / Audio
2276 CODEC, connected through MicroWire and I@math{^2}S busses
2278 GPIO-connected matrix keypad
2280 Secure Digital card connected to OMAP MMC/SD host
2285 Nokia N800 and N810 internet tablets (known also as RX-34 and RX-44 / 48)
2286 emulation supports the following elements:
2290 Texas Instruments OMAP2420 System-on-chip (ARM 1136 core)
2292 RAM and non-volatile OneNAND Flash memories
2294 Display connected to EPSON remote framebuffer chip and OMAP on-chip
2295 display controller and a LS041y3 MIPI DBI-C controller
2297 TI TSC2301 (in N800) and TI TSC2005 (in N810) touchscreen controllers
2298 driven through SPI bus
2300 National Semiconductor LM8323-controlled qwerty keyboard driven
2301 through I@math{^2}C bus
2303 Secure Digital card connected to OMAP MMC/SD host
2305 Three OMAP on-chip UARTs and on-chip STI debugging console
2307 A Bluetooth(R) transceiver and HCI connected to an UART
2309 Mentor Graphics "Inventra" dual-role USB controller embedded in a TI
2310 TUSB6010 chip - only USB host mode is supported
2312 TI TMP105 temperature sensor driven through I@math{^2}C bus
2314 TI TWL92230C power management companion with an RTC on I@math{^2}C bus
2316 Nokia RETU and TAHVO multi-purpose chips with an RTC, connected
2320 The Luminary Micro Stellaris LM3S811EVB emulation includes the following
2327 64k Flash and 8k SRAM.
2329 Timers, UARTs, ADC and I@math{^2}C interface.
2331 OSRAM Pictiva 96x16 OLED with SSD0303 controller on I@math{^2}C bus.
2334 The Luminary Micro Stellaris LM3S6965EVB emulation includes the following
2341 256k Flash and 64k SRAM.
2343 Timers, UARTs, ADC, I@math{^2}C and SSI interfaces.
2345 OSRAM Pictiva 128x64 OLED with SSD0323 controller connected via SSI.
2348 The Freecom MusicPal internet radio emulation includes the following
2353 Marvell MV88W8618 ARM core.
2355 32 MB RAM, 256 KB SRAM, 8 MB flash.
2359 MV88W8xx8 Ethernet controller
2361 MV88W8618 audio controller, WM8750 CODEC and mixer
2363 128×64 display with brightness control
2365 2 buttons, 2 navigation wheels with button function
2368 The Siemens SX1 models v1 and v2 (default) basic emulation.
2369 The emulation includes the following elements:
2373 Texas Instruments OMAP310 System-on-chip (ARM 925T core)
2375 ROM and RAM memories (ROM firmware image can be loaded with -pflash)
2377 1 Flash of 16MB and 1 Flash of 8MB
2381 On-chip LCD controller
2383 On-chip Real Time Clock
2385 Secure Digital card connected to OMAP MMC/SD host
2390 A Linux 2.6 test image is available on the QEMU web site. More
2391 information is available in the QEMU mailing-list archive.
2393 @c man begin OPTIONS
2395 The following options are specific to the ARM emulation:
2400 Enable semihosting syscall emulation.
2402 On ARM this implements the "Angel" interface.
2404 Note that this allows guest direct access to the host filesystem,
2405 so should only be used with trusted guest OS.
2411 @node ColdFire System emulator
2412 @section ColdFire System emulator
2413 @cindex system emulation (ColdFire)
2414 @cindex system emulation (M68K)
2416 Use the executable @file{qemu-system-m68k} to simulate a ColdFire machine.
2417 The emulator is able to boot a uClinux kernel.
2419 The M5208EVB emulation includes the following devices:
2423 MCF5208 ColdFire V2 Microprocessor (ISA A+ with EMAC).
2425 Three Two on-chip UARTs.
2427 Fast Ethernet Controller (FEC)
2430 The AN5206 emulation includes the following devices:
2434 MCF5206 ColdFire V2 Microprocessor.
2439 @c man begin OPTIONS
2441 The following options are specific to the ColdFire emulation:
2446 Enable semihosting syscall emulation.
2448 On M68K this implements the "ColdFire GDB" interface used by libgloss.
2450 Note that this allows guest direct access to the host filesystem,
2451 so should only be used with trusted guest OS.
2457 @node Cris System emulator
2458 @section Cris System emulator
2459 @cindex system emulation (Cris)
2463 @node Microblaze System emulator
2464 @section Microblaze System emulator
2465 @cindex system emulation (Microblaze)
2469 @node SH4 System emulator
2470 @section SH4 System emulator
2471 @cindex system emulation (SH4)
2475 @node Xtensa System emulator
2476 @section Xtensa System emulator
2477 @cindex system emulation (Xtensa)
2479 Two executables cover simulation of both Xtensa endian options,
2480 @file{qemu-system-xtensa} and @file{qemu-system-xtensaeb}.
2481 Two different machine types are emulated:
2485 Xtensa emulator pseudo board "sim"
2487 Avnet LX60/LX110/LX200 board
2490 The sim pseudo board emulation provides an environment similar
2491 to one provided by the proprietary Tensilica ISS.
2496 A range of Xtensa CPUs, default is the DC232B
2498 Console and filesystem access via semihosting calls
2501 The Avnet LX60/LX110/LX200 emulation supports:
2505 A range of Xtensa CPUs, default is the DC232B
2509 OpenCores 10/100 Mbps Ethernet MAC
2512 @c man begin OPTIONS
2514 The following options are specific to the Xtensa emulation:
2519 Enable semihosting syscall emulation.
2521 Xtensa semihosting provides basic file IO calls, such as open/read/write/seek/select.
2522 Tensilica baremetal libc for ISS and linux platform "sim" use this interface.
2524 Note that this allows guest direct access to the host filesystem,
2525 so should only be used with trusted guest OS.
2531 @node QEMU Guest Agent
2532 @chapter QEMU Guest Agent invocation
2534 @include qemu-ga.texi
2536 @node QEMU User space emulator
2537 @chapter QEMU User space emulator
2540 * Supported Operating Systems ::
2542 * Linux User space emulator::
2543 * BSD User space emulator ::
2546 @node Supported Operating Systems
2547 @section Supported Operating Systems
2549 The following OS are supported in user space emulation:
2553 Linux (referred as qemu-linux-user)
2555 BSD (referred as qemu-bsd-user)
2561 QEMU user space emulation has the following notable features:
2564 @item System call translation:
2565 QEMU includes a generic system call translator. This means that
2566 the parameters of the system calls can be converted to fix
2567 endianness and 32/64-bit mismatches between hosts and targets.
2568 IOCTLs can be converted too.
2570 @item POSIX signal handling:
2571 QEMU can redirect to the running program all signals coming from
2572 the host (such as @code{SIGALRM}), as well as synthesize signals from
2573 virtual CPU exceptions (for example @code{SIGFPE} when the program
2574 executes a division by zero).
2576 QEMU relies on the host kernel to emulate most signal system
2577 calls, for example to emulate the signal mask. On Linux, QEMU
2578 supports both normal and real-time signals.
2581 On Linux, QEMU can emulate the @code{clone} syscall and create a real
2582 host thread (with a separate virtual CPU) for each emulated thread.
2583 Note that not all targets currently emulate atomic operations correctly.
2584 x86 and ARM use a global lock in order to preserve their semantics.
2587 QEMU was conceived so that ultimately it can emulate itself. Although
2588 it is not very useful, it is an important test to show the power of the
2591 @node Linux User space emulator
2592 @section Linux User space emulator
2597 * Command line options::
2602 @subsection Quick Start
2604 In order to launch a Linux process, QEMU needs the process executable
2605 itself and all the target (x86) dynamic libraries used by it.
2609 @item On x86, you can just try to launch any process by using the native
2613 qemu-i386 -L / /bin/ls
2616 @code{-L /} tells that the x86 dynamic linker must be searched with a
2619 @item Since QEMU is also a linux process, you can launch QEMU with
2620 QEMU (NOTE: you can only do that if you compiled QEMU from the sources):
2623 qemu-i386 -L / qemu-i386 -L / /bin/ls
2626 @item On non x86 CPUs, you need first to download at least an x86 glibc
2627 (@file{qemu-runtime-i386-XXX-.tar.gz} on the QEMU web page). Ensure that
2628 @code{LD_LIBRARY_PATH} is not set:
2631 unset LD_LIBRARY_PATH
2634 Then you can launch the precompiled @file{ls} x86 executable:
2637 qemu-i386 tests/i386/ls
2639 You can look at @file{scripts/qemu-binfmt-conf.sh} so that
2640 QEMU is automatically launched by the Linux kernel when you try to
2641 launch x86 executables. It requires the @code{binfmt_misc} module in the
2644 @item The x86 version of QEMU is also included. You can try weird things such as:
2646 qemu-i386 /usr/local/qemu-i386/bin/qemu-i386 \
2647 /usr/local/qemu-i386/bin/ls-i386
2653 @subsection Wine launch
2657 @item Ensure that you have a working QEMU with the x86 glibc
2658 distribution (see previous section). In order to verify it, you must be
2662 qemu-i386 /usr/local/qemu-i386/bin/ls-i386
2665 @item Download the binary x86 Wine install
2666 (@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page).
2668 @item Configure Wine on your account. Look at the provided script
2669 @file{/usr/local/qemu-i386/@/bin/wine-conf.sh}. Your previous
2670 @code{$@{HOME@}/.wine} directory is saved to @code{$@{HOME@}/.wine.org}.
2672 @item Then you can try the example @file{putty.exe}:
2675 qemu-i386 /usr/local/qemu-i386/wine/bin/wine \
2676 /usr/local/qemu-i386/wine/c/Program\ Files/putty.exe
2681 @node Command line options
2682 @subsection Command line options
2685 @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}...]
2692 Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)
2694 Set the x86 stack size in bytes (default=524288)
2696 Select CPU model (-cpu help for list and additional feature selection)
2697 @item -E @var{var}=@var{value}
2698 Set environment @var{var} to @var{value}.
2700 Remove @var{var} from the environment.
2702 Offset guest address by the specified number of bytes. This is useful when
2703 the address region required by guest applications is reserved on the host.
2704 This option is currently only supported on some hosts.
2706 Pre-allocate a guest virtual address space of the given size (in bytes).
2707 "G", "M", and "k" suffixes may be used when specifying the size.
2714 Activate logging of the specified items (use '-d help' for a list of log items)
2716 Act as if the host page size was 'pagesize' bytes
2718 Wait gdb connection to port
2720 Run the emulation in single step mode.
2723 Environment variables:
2727 Print system calls and arguments similar to the 'strace' program
2728 (NOTE: the actual 'strace' program will not work because the user
2729 space emulator hasn't implemented ptrace). At the moment this is
2730 incomplete. All system calls that don't have a specific argument
2731 format are printed with information for six arguments. Many
2732 flag-style arguments don't have decoders and will show up as numbers.
2735 @node Other binaries
2736 @subsection Other binaries
2738 @cindex user mode (Alpha)
2739 @command{qemu-alpha} TODO.
2741 @cindex user mode (ARM)
2742 @command{qemu-armeb} TODO.
2744 @cindex user mode (ARM)
2745 @command{qemu-arm} is also capable of running ARM "Angel" semihosted ELF
2746 binaries (as implemented by the arm-elf and arm-eabi Newlib/GDB
2747 configurations), and arm-uclinux bFLT format binaries.
2749 @cindex user mode (ColdFire)
2750 @cindex user mode (M68K)
2751 @command{qemu-m68k} is capable of running semihosted binaries using the BDM
2752 (m5xxx-ram-hosted.ld) or m68k-sim (sim.ld) syscall interfaces, and
2753 coldfire uClinux bFLT format binaries.
2755 The binary format is detected automatically.
2757 @cindex user mode (Cris)
2758 @command{qemu-cris} TODO.
2760 @cindex user mode (i386)
2761 @command{qemu-i386} TODO.
2762 @command{qemu-x86_64} TODO.
2764 @cindex user mode (Microblaze)
2765 @command{qemu-microblaze} TODO.
2767 @cindex user mode (MIPS)
2768 @command{qemu-mips} executes 32-bit big endian MIPS binaries (MIPS O32 ABI).
2770 @command{qemu-mipsel} executes 32-bit little endian MIPS binaries (MIPS O32 ABI).
2772 @command{qemu-mips64} executes 64-bit big endian MIPS binaries (MIPS N64 ABI).
2774 @command{qemu-mips64el} executes 64-bit little endian MIPS binaries (MIPS N64 ABI).
2776 @command{qemu-mipsn32} executes 32-bit big endian MIPS binaries (MIPS N32 ABI).
2778 @command{qemu-mipsn32el} executes 32-bit little endian MIPS binaries (MIPS N32 ABI).
2780 @cindex user mode (NiosII)
2781 @command{qemu-nios2} TODO.
2783 @cindex user mode (PowerPC)
2784 @command{qemu-ppc64abi32} TODO.
2785 @command{qemu-ppc64} TODO.
2786 @command{qemu-ppc} TODO.
2788 @cindex user mode (SH4)
2789 @command{qemu-sh4eb} TODO.
2790 @command{qemu-sh4} TODO.
2792 @cindex user mode (SPARC)
2793 @command{qemu-sparc} can execute Sparc32 binaries (Sparc32 CPU, 32 bit ABI).
2795 @command{qemu-sparc32plus} can execute Sparc32 and SPARC32PLUS binaries
2796 (Sparc64 CPU, 32 bit ABI).
2798 @command{qemu-sparc64} can execute some Sparc64 (Sparc64 CPU, 64 bit ABI) and
2799 SPARC32PLUS binaries (Sparc64 CPU, 32 bit ABI).
2801 @node BSD User space emulator
2802 @section BSD User space emulator
2807 * BSD Command line options::
2811 @subsection BSD Status
2815 target Sparc64 on Sparc64: Some trivial programs work.
2818 @node BSD Quick Start
2819 @subsection Quick Start
2821 In order to launch a BSD process, QEMU needs the process executable
2822 itself and all the target dynamic libraries used by it.
2826 @item On Sparc64, you can just try to launch any process by using the native
2830 qemu-sparc64 /bin/ls
2835 @node BSD Command line options
2836 @subsection Command line options
2839 @command{qemu-sparc64} [@option{-h]} [@option{-d]} [@option{-L} @var{path}] [@option{-s} @var{size}] [@option{-bsd} @var{type}] @var{program} [@var{arguments}...]
2846 Set the library root path (default=/)
2848 Set the stack size in bytes (default=524288)
2849 @item -ignore-environment
2850 Start with an empty environment. Without this option,
2851 the initial environment is a copy of the caller's environment.
2852 @item -E @var{var}=@var{value}
2853 Set environment @var{var} to @var{value}.
2855 Remove @var{var} from the environment.
2857 Set the type of the emulated BSD Operating system. Valid values are
2858 FreeBSD, NetBSD and OpenBSD (default).
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 Run the emulation in single step mode.
2872 @node System requirements
2873 @chapter System requirements
2875 @section KVM kernel module
2877 On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator
2878 require the host to be running Linux v4.5 or newer.
2880 The OpteronG[345] CPU models require KVM support for RDTSCP, which was
2881 added with Linux 4.5 which is supported by the major distros. And even
2882 if RHEL7 has kernel 3.10, KVM there has the required functionality there
2883 to make it close to a 4.5 or newer kernel.
2885 @include docs/security.texi
2887 @include qemu-tech.texi
2889 @include qemu-deprecated.texi
2891 @node Supported build platforms
2892 @appendix Supported build platforms
2894 QEMU aims to support building and executing on multiple host OS platforms.
2895 This appendix outlines which platforms are the major build targets. These
2896 platforms are used as the basis for deciding upon the minimum required
2897 versions of 3rd party software QEMU depends on. The supported platforms
2898 are the targets for automated testing performed by the project when patches
2899 are submitted for review, and tested before and after merge.
2901 If a platform is not listed here, it does not imply that QEMU won't work.
2902 If an unlisted platform has comparable software versions to a listed platform,
2903 there is every expectation that it will work. Bug reports are welcome for
2904 problems encountered on unlisted platforms unless they are clearly older
2905 vintage than what is described here.
2907 Note that when considering software versions shipped in distros as support
2908 targets, QEMU considers only the version number, and assumes the features in
2909 that distro match the upstream release with the same version. In other words,
2910 if a distro backports extra features to the software in their distro, QEMU
2911 upstream code will not add explicit support for those backports, unless the
2912 feature is auto-detectable in a manner that works for the upstream releases
2915 The Repology site @url{https://repology.org} is a useful resource to identify
2916 currently shipped versions of software in various operating systems, though
2917 it does not cover all distros listed below.
2921 For distributions with frequent, short-lifetime releases, the project will
2922 aim to support all versions that are not end of life by their respective
2923 vendors. For the purposes of identifying supported software versions, the
2924 project will look at Fedora, Ubuntu, and openSUSE distros. Other short-
2925 lifetime distros will be assumed to ship similar software versions.
2927 For distributions with long-lifetime releases, the project will aim to support
2928 the most recent major version at all times. Support for the previous major
2929 version will be dropped 2 years after the new major version is released. For
2930 the purposes of identifying supported software versions, the project will look
2931 at RHEL, Debian, Ubuntu LTS, and SLES distros. Other long-lifetime distros will
2932 be assumed to ship similar software versions.
2936 The project supports building with current versions of the MinGW toolchain,
2941 The project supports building with the two most recent versions of macOS, with
2942 the current homebrew package set available.
2946 The project aims to support the all the versions which are not end of life.
2950 The project aims to support the most recent major version at all times. Support
2951 for the previous major version will be dropped 2 years after the new major
2952 version is released.
2956 The project aims to support the all the versions which are not end of life.
2961 QEMU is a trademark of Fabrice Bellard.
2963 QEMU is released under the
2964 @url{https://www.gnu.org/licenses/gpl-2.0.txt,GNU General Public License},
2965 version 2. Parts of QEMU have specific licenses, see file
2966 @url{https://git.qemu.org/?p=qemu.git;a=blob_plain;f=LICENSE,LICENSE}.
2980 @section Concept Index
2981 This is the main index. Should we combine all keywords in one index? TODO
2984 @node Function Index
2985 @section Function Index
2986 This index could be used for command line options and monitor functions.
2989 @node Keystroke Index
2990 @section Keystroke Index
2992 This is a list of all keystrokes which have a special function
2993 in system emulation.
2998 @section Program Index
3001 @node Data Type Index
3002 @section Data Type Index
3004 This index could be used for qdev device names and options.
3008 @node Variable Index
3009 @section Variable Index