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1. Introduction 2. Installation 3. QEMU PC System emulator 4. QEMU System emulator for non PC targets 5. QEMU User space emulator 6. Compilation from the sources 7. Index
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1.1 Features
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QEMU is a FAST! processor emulator using dynamic translation to achieve good emulation speed.
QEMU has two operating modes:
QEMU can run without an host kernel driver and yet gives acceptable performance.
For system emulation, the following hardware targets are supported:
For user emulation, x86, PowerPC, ARM, 32-bit MIPS, Sparc32/64, ColdFire(m68k), CRISv32 and MicroBlaze CPUs are supported.
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If you want to compile QEMU yourself, see 6. Compilation from the sources.
2.1 Linux 2.2 Windows 2.3 Mac OS X Macintosh
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If a precompiled package is available for your distribution - you just have to install it. Otherwise, see 6. Compilation from the sources.
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Download the experimental binary installer at http://www.free.oszoo.org/@/download.html.
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Download the experimental binary installer at http://www.free.oszoo.org/@/download.html.
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The QEMU PC System emulator simulates the following peripherals:
SMP is supported with up to 255 CPUs.
Note that adlib, gus and cs4231a are only available when QEMU was configured with --audio-card-list option containing the name(s) of required card(s).
QEMU uses the PC BIOS from the Bochs project and the Plex86/Bochs LGPL VGA BIOS.
QEMU uses YM3812 emulation by Tatsuyuki Satoh.
QEMU uses GUS emulation(GUSEMU32 http://www.deinmeister.de/gusemu/) by Tibor "TS" Schütz.
Not that, by default, GUS shares IRQ(7) with parallel ports and so qemu must be told to not have parallel ports to have working GUS
qemu dos.img -soundhw gus -parallel none |
Alternatively:
qemu dos.img -device gus,irq=5 |
Or some other unclaimed IRQ.
CS4231A is the chip used in Windows Sound System and GUSMAX products
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Download and uncompress the linux image (`linux.img') and type:
qemu linux.img |
Linux should boot and give you a prompt.
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usage: qemu [options] [disk_image] |
disk_image is a raw hard disk image for IDE hard disk 0. Some targets do not need a disk image.
Standard options:
-M ? for list)
Define a new drive. Valid options are:
By default, writethrough caching is used for all block device. This means that the host page cache will be used to read and write data but write notification will be sent to the guest only when the data has been reported as written by the storage subsystem.
Writeback caching will report data writes as completed as soon as the data is present in the host page cache. This is safe as long as you trust your host. If your host crashes or loses power, then the guest may experience data corruption. When using the `-snapshot' option, writeback caching is used by default.
The host page cache can be avoided entirely with `cache=none'. This will attempt to do disk IO directly to the guests memory. QEMU may still perform an internal copy of the data.
Some block drivers perform badly with `cache=writethrough', most notably, qcow2. If performance is more important than correctness, `cache=writeback' should be used with qcow2.
Instead of `-cdrom' you can use:
qemu -drive file=file,index=2,media=cdrom |
Instead of `-hda', `-hdb', `-hdc', `-hdd', you can use:
qemu -drive file=file,index=0,media=disk qemu -drive file=file,index=1,media=disk qemu -drive file=file,index=2,media=disk qemu -drive file=file,index=3,media=disk |
You can connect a CDROM to the slave of ide0:
qemu -drive file=file,if=ide,index=1,media=cdrom |
If you don't specify the "file=" argument, you define an empty drive:
qemu -drive if=ide,index=1,media=cdrom |
You can connect a SCSI disk with unit ID 6 on the bus #0:
qemu -drive file=file,if=scsi,bus=0,unit=6 |
Instead of `-fda', `-fdb', you can use:
qemu -drive file=file,index=0,if=floppy qemu -drive file=file,index=1,if=floppy |
By default, interface is "ide" and index is automatically incremented:
qemu -drive file=a -drive file=b" |
qemu -hda a -hdb b |
Specify boot order drives as a string of drive letters. Valid drive letters depend on the target achitecture. The x86 PC uses: a, b (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot from network adapter 1-4), hard disk boot is the default. To apply a particular boot order only on the first startup, specify it via `once'.
Interactive boot menus/prompts can be enabled via `menu=on' as far as firmware/BIOS supports them. The default is non-interactive boot.
# try to boot from network first, then from hard disk qemu -boot order=nc # boot from CD-ROM first, switch back to default order after reboot qemu -boot once=d |
Note: The legacy format '-boot drives' is still supported but its use is discouraged as it may be removed from future versions.
Use keyboard layout language (for example fr for
French). This option is only needed where it is not easy to get raw PC
keycodes (e.g. on Macs, with some X11 servers or with a VNC
display). You don't normally need to use it on PC/Linux or PC/Windows
hosts.
The available layouts are:
ar de-ch es fo fr-ca hu ja mk no pt-br sv da en-gb et fr fr-ch is lt nl pl ru th de en-us fi fr-be hr it lv nl-be pt sl tr |
The default is en-us.
Will show the audio subsystem help: list of drivers, tunable parameters.
Enable audio and selected sound hardware. Use ? to print all available sound hardware.
qemu -soundhw sb16,adlib disk.img qemu -soundhw es1370 disk.img qemu -soundhw ac97 disk.img qemu -soundhw all disk.img qemu -soundhw ? |
Note that Linux's i810_audio OSS kernel (for AC97) module might require manually specifying clocking.
modprobe i810_audio clocking=48000 |
format=raw to avoid interpreting an untrusted format header.
-serial for the
available devices.
Display options:
Normally, QEMU uses SDL to display the VGA output. With this option, you can totally disable graphical output so that QEMU is a simple command line application. The emulated serial port is redirected on the console. Therefore, you can still use QEMU to debug a Linux kernel with a serial console.
Normally, QEMU uses SDL to display the VGA output. With this option, QEMU can display the VGA output when in text mode using a curses/ncurses interface. Nothing is displayed in graphical mode.
Do not use decorations for SDL windows and start them using the whole available screen space. This makes the using QEMU in a dedicated desktop workspace more convenient.
Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt).
Use Right-Ctrl to grab mouse (instead of Ctrl-Alt).
Disable SDL window close capability.
Enable SDL.
Rotate graphical output 90 deg left (only PXA LCD).
Normally, QEMU uses SDL to display the VGA output. With this option, you can have QEMU listen on VNC display display and redirect the VGA display over the VNC session. It is very useful to enable the usb tablet device when using this option (option `-usbdevice tablet'). When using the VNC display, you must use the `-k' parameter to set the keyboard layout if you are not using en-us. Valid syntax for the display is
TCP connections will only be allowed from host on display d. By convention the TCP port is 5900+d. Optionally, host can be omitted in which case the server will accept connections from any host.
Connections will be allowed over UNIX domain sockets where path is the location of a unix socket to listen for connections on.
VNC is initialized but not started. The monitor change command
can be used to later start the VNC server.
Following the display value there may be one or more option flags separated by commas. Valid options are
Connect to a listening VNC client via a "reverse" connection. The
client is specified by the display. For reverse network
connections (host:d,reverse), the d argument
is a TCP port number, not a display number.
Require that password based authentication is used for client connections.
The password must be set separately using the change command in the
3.5 QEMU Monitor
Require that client use TLS when communicating with the VNC server. This uses anonymous TLS credentials so is susceptible to a man-in-the-middle attack. It is recommended that this option be combined with either the `x509' or `x509verify' options.
Valid if `tls' is specified. Require that x509 credentials are used for negotiating the TLS session. The server will send its x509 certificate to the client. It is recommended that a password be set on the VNC server to provide authentication of the client when this is used. The path following this option specifies where the x509 certificates are to be loaded from. See the 3.10 VNC security section for details on generating certificates.
Valid if `tls' is specified. Require that x509 credentials are used for negotiating the TLS session. The server will send its x509 certificate to the client, and request that the client send its own x509 certificate. The server will validate the client's certificate against the CA certificate, and reject clients when validation fails. If the certificate authority is trusted, this is a sufficient authentication mechanism. You may still wish to set a password on the VNC server as a second authentication layer. The path following this option specifies where the x509 certificates are to be loaded from. See the 3.10 VNC security section for details on generating certificates.
Require that the client use SASL to authenticate with the VNC server. The exact choice of authentication method used is controlled from the system / user's SASL configuration file for the 'qemu' service. This is typically found in /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, an environment variable SASL_CONF_PATH can be used to make it search alternate locations for the service config. While some SASL auth methods can also provide data encryption (eg GSSAPI), it is recommended that SASL always be combined with the 'tls' and 'x509' settings to enable use of SSL and server certificates. This ensures a data encryption preventing compromise of authentication credentials. See the 3.10 VNC security section for details on using SASL authentication.
Turn on access control lists for checking of the x509 client certificate
and SASL party. For x509 certs, the ACL check is made against the
certificate's distinguished name. This is something that looks like
C=GB,O=ACME,L=Boston,CN=bob. For SASL party, the ACL check is
made against the username, which depending on the SASL plugin, may
include a realm component, eg bob or bob@EXAMPLE.COM.
When the `acl' flag is set, the initial access list will be
empty, with a deny policy. Thus no one will be allowed to
use the VNC server until the ACLs have been loaded. This can be
achieved using the acl monitor command.
i386 target only:
virtio, i82551, i82557b, i82559er,
ne2k_pci, ne2k_isa, pcnet, rtl8139,
e1000, smc91c111, lance and mcf_fec.
Not all devices are supported on all targets. Use -net nic,model=?
for a list of available devices for your target.
bin of the Unix TFTP client).
Example (using pxelinux):
qemu -hda linux.img -boot n -net user,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 |
In the guest Windows OS, the line:
10.0.2.4 smbserver |
Then `dir' can be accessed in `\\smbserver\qemu'.
Note that a SAMBA server must be installed on the host OS in `/usr/sbin/smbd'. QEMU was tested successfully with smbd versions from Red Hat 9, Fedora Core 3 and OpenSUSE 11.x.
For example, to redirect host X11 connection from screen 1 to guest screen 0, use the following:
# on the host qemu -net user,hostfwd=tcp:127.0.0.1:6001-:6000 [...] # this host xterm should open in the guest X11 server xterm -display :1 |
To redirect telnet connections from host port 5555 to telnet port on the guest, use the following:
# on the host qemu -net user,hostfwd=tcp::5555-:23 [...] telnet localhost 5555 |
Then when you use on the host telnet localhost 5555, you
connect to the guest telnet server.
Note: Legacy stand-alone options -tftp, -bootp, -smb and -redir are still processed and applied to -net user. Mixing them with the new configuration syntax gives undefined results. Their use for new applications is discouraged as they will be removed from future versions.
qemu linux.img -net nic -net tap |
More complicated example (two NICs, each one connected to a TAP device)
qemu linux.img -net nic,vlan=0 -net tap,vlan=0,ifname=tap0 \ -net nic,vlan=1 -net tap,vlan=1,ifname=tap1 |
Connect the VLAN n to a remote VLAN in another QEMU virtual machine using a TCP socket connection. If `listen' is specified, QEMU waits for incoming connections on port (host is optional). `connect' is used to connect to another QEMU instance using the `listen' option. `fd'=h specifies an already opened TCP socket.
Example:
# launch a first QEMU instance qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \ -net socket,listen=:1234 # connect the VLAN 0 of this instance to the VLAN 0 # of the first instance qemu linux.img -net nic,macaddr=52:54:00:12:34:57 \ -net socket,connect=127.0.0.1:1234 |
Create a VLAN n shared with another QEMU virtual machines using a UDP multicast socket, effectively making a bus for every QEMU with same multicast address maddr and port. NOTES:
Example:
# launch one QEMU instance qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \ -net socket,mcast=230.0.0.1:1234 # launch another QEMU instance on same "bus" qemu linux.img -net nic,macaddr=52:54:00:12:34:57 \ -net socket,mcast=230.0.0.1:1234 # launch yet another QEMU instance on same "bus" qemu linux.img -net nic,macaddr=52:54:00:12:34:58 \ -net socket,mcast=230.0.0.1:1234 |
Example (User Mode Linux compat.):
# launch QEMU instance (note mcast address selected # is UML's default) qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \ -net socket,mcast=239.192.168.1:1102 # launch UML /path/to/linux ubd0=/path/to/root_fs eth0=mcast |
Example:
# launch vde switch vde_switch -F -sock /tmp/myswitch # launch QEMU instance qemu linux.img -net nic -net vde,sock=/tmp/myswitch |
Character device options:
The general form of a character device option is:
Backend is one of: `null', `socket', `udp', `msmouse', `vc', `file', `pipe', `console', `serial', `pty', `stdio', `braille', `tty', `parport'. The specific backend will determine the applicable options.
All devices must have an id, which can be any string up to 127 characters long. It is used to uniquely identify this device in other command line directives.
Options to each backend are described below.
Create a two-way stream socket, which can be either a TCP or a unix socket. A unix socket will be created if `path' is specified. Behaviour is undefined if TCP options are specified for a unix socket.
`server' specifies that the socket shall be a listening socket.
`nowait' specifies that QEMU should not block waiting for a client to connect to a listening socket.
`telnet' specifies that traffic on the socket should interpret telnet escape sequences.
TCP and unix socket options are given below:
`host' for a listening socket specifies the local address to be bound.
For a connecting socket species the remote host to connect to. `host' is
optional for listening sockets. If not specified it defaults to 0.0.0.0.
`port' for a listening socket specifies the local port to be bound. For a connecting socket specifies the port on the remote host to connect to. `port' can be given as either a port number or a service name. `port' is required.
`to' is only relevant to listening sockets. If it is specified, and `port' cannot be bound, QEMU will attempt to bind to subsequent ports up to and including `to' until it succeeds. `to' must be specified as a port number.
`ipv4' and `ipv6' specify that either IPv4 or IPv6 must be used. If neither is specified the socket may use either protocol.
`nodelay' disables the Nagle algorithm.
`path' specifies the local path of the unix socket. `path' is required.
Sends all traffic from the guest to a remote host over UDP.
`host' specifies the remote host to connect to. If not specified it
defaults to localhost.
`port' specifies the port on the remote host to connect to. `port' is required.
`localaddr' specifies the local address to bind to. If not specified it
defaults to 0.0.0.0.
`localport' specifies the local port to bind to. If not specified any available local port will be used.
`ipv4' and `ipv6' specify that either IPv4 or IPv6 must be used. If neither is specified the device may use either protocol.
Forward QEMU's emulated msmouse events to the guest. `msmouse' does not take any options.
Connect to a QEMU text console. `vc' may optionally be given a specific size.
`width' and `height' specify the width and height respectively of the console, in pixels.
`cols' and `rows' specify that the console be sized to fit a text console with the given dimensions.
Log all traffic received from the guest to a file.
`path' specifies the path of the file to be opened. This file will be created if it does not already exist, and overwritten if it does. `path' is required.
Create a two-way connection to the guest. The behaviour differs slightly between Windows hosts and other hosts:
On Windows, a single duplex pipe will be created at `\\.pipe\`path''.
On other hosts, 2 pipes will be created called ``path'.in' and ``path'.out'. Data written to ``path'.in' will be received by the guest. Data written by the guest can be read from ``path'.out'. QEMU will not create these fifos, and requires them to be present.
`path' forms part of the pipe path as described above. `path' is required.
Send traffic from the guest to QEMU's standard output. `console' does not take any options.
`console' is only available on Windows hosts.
Send traffic from the guest to a serial device on the host.
`serial' is only available on Windows hosts.
`path' specifies the name of the serial device to open.
Create a new pseudo-terminal on the host and connect to it. `pty' does not take any options.
`pty' is not available on Windows hosts.
Connect to a local BrlAPI server. `braille' does not take any options.
Connect to a local tty device.
`tty' is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and DragonFlyBSD hosts.
`path' specifies the path to the tty. `path' is required.
`parport' is only available on Linux, FreeBSD and DragonFlyBSD hosts.
Connect to a local parallel port.
`path' specifies the path to the parallel port device. `path' is required.
Bluetooth(R) options:
-bt hci[...] option is valid and defines the HCI's
logic. The Transport Layer is decided by the machine type. Currently
the machines n800 and n810 have one HCI and all other
machines have none.
The following three types are recognized:
bluez only) The corresponding HCI passes commands / events
to / from the physical HCI identified by the name id (default:
hci0) on the computer running QEMU. Only available on bluez
capable systems like Linux.
0). Similarly to `-net'
VLANs, devices inside a bluetooth network n can only communicate
with other devices in the same network (scatternet).
vhci driver installed. Can
be used as following:
qemu [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5 |
0). QEMU can only emulate one type of bluetooth devices
currently:
Linux/Multiboot boot specific:
When using these options, you can use a given Linux or Multiboot kernel without installing it in the disk image. It can be useful for easier testing of various kernels.
This syntax is only available with multiboot.
Use file1 and file2 as modules and pass arg=foo as parameter to the first module.
Debug/Expert options:
vc in graphical mode and
stdio in non graphical mode.
This option can be used several times to simulate up to 4 serial ports.
Use -serial none to disable all serial ports.
Available character devices are:
vc:800x600 |
vc:80Cx24C |
0.0.0.0.
When not using a specified src_port a random port is automatically chosen.
If you just want a simple readonly console you can use netcat or
nc, by starting qemu with: -serial udp::4555 and nc as:
nc -u -l -p 4555. Any time qemu writes something to that port it
will appear in the netconsole session.
If you plan to send characters back via netconsole or you want to stop
and start qemu a lot of times, you should have qemu use the same
source port each time by using something like -serial
udp::4555@:4556 to qemu. Another approach is to use a patched
version of netcat which can listen to a TCP port and send and receive
characters via udp. If you have a patched version of netcat which
activates telnet remote echo and single char transfer, then you can
use the following options to step up a netcat redirector to allow
telnet on port 5555 to access the qemu port.
Qemu Options:
netcat options:
telnet options:
nowait
option was specified. The nodelay option disables the Nagle buffering
algorithm. If host is omitted, 0.0.0.0 is assumed. Only
one TCP connection at a time is accepted. You can use telnet to
connect to the corresponding character device.
Example to send tcp console to 192.168.0.2 port 4444
Example to listen and wait on port 4444 for connection
Example to not wait and listen on ip 192.168.0.100 port 4444
-serial tcp. The
difference is that the port acts like a telnet server or client using
telnet option negotiation. This will also allow you to send the
MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
sequence. Typically in unix telnet you do it with Control-] and then
type "send break" followed by pressing the enter key.
-serial tcp except the unix domain socket
path is used for connections.
-serial mon:telnet::4444,server,nowait
This option can be used several times to simulate up to 3 parallel ports.
Use -parallel none to disable all parallel ports.
vc in graphical mode and stdio in
non graphical mode.
(gdb) target remote | exec qemu -gdb stdio ... |
loadvm in monitor)
utc or localtime to let the RTC start at the current
UTC or local time, respectively. localtime is required for correct date in
MS-DOS or Windows. To start at a specific point in time, provide date in the
format 2006-06-17T16:01:21 or 2006-06-17. The default base is UTC.
By default the RTC is driven by the host system time. This allows to use the
RTC as accurate reference clock inside the guest, specifically if the host
time is smoothly following an accurate external reference clock, e.g. via NTP.
If you want to isolate the guest time from the host, even prevent it from
progressing during suspension, you can set `clock' to vm instead.
Enable `driftfix' (i386 targets only) if you experience time drift problems, specifically with Windows' ACPI HAL. This option will try to figure out how many timer interrupts were not processed by the Windows guest and will re-inject them.
auto is specified
then the virtual cpu speed will be automatically adjusted to keep virtual
time within a few seconds of real time.
Note that while this option can give deterministic behavior, it does not provide cycle accurate emulation. Modern CPUs contain superscalar out of order cores with complex cache hierarchies. The number of instructions executed often has little or no correlation with actual performance.
The model is the model of hardware watchdog to emulate. Choices
for model are: ib700 (iBASE 700) which is a very simple ISA
watchdog with a single timer, or i6300esb (Intel 6300ESB I/O
controller hub) which is a much more featureful PCI-based dual-timer
watchdog. Choose a model for which your guest has drivers.
Use -watchdog ? to list available hardware models. Only one
watchdog can be enabled for a guest.
The action controls what QEMU will do when the watchdog timer
expires.
The default is
reset (forcefully reset the guest).
Other possible actions are:
shutdown (attempt to gracefully shutdown the guest),
poweroff (forcefully poweroff the guest),
pause (pause the guest),
debug (print a debug message and continue), or
none (do nothing).
Note that the shutdown action requires that the guest responds
to ACPI signals, which it may not be able to do in the sort of
situations where the watchdog would have expired, and thus
-watchdog-action shutdown is not recommended for production use.
Examples:
-watchdog i6300esb -watchdog-action pause
-watchdog ib700
0x01 when using the
-nographic option. 0x01 is equal to pressing
Control-a. You can select a different character from the ascii
control keys where 1 through 26 map to Control-a through Control-z. For
instance you could use the either of the following to change the escape
character to Control-t.
-echr 0x14
-echr 20
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During the graphical emulation, you can use the following keys:
In the virtual consoles, you can use Ctrl-Up, Ctrl-Down, Ctrl-PageUp and Ctrl-PageDown to move in the back log.
During emulation, if you are using the `-nographic' option, use Ctrl-a h to get terminal commands:
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The QEMU monitor is used to give complex commands to the QEMU emulator. You can use it to:
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The following commands are available:
Change the configuration of a device.
(qemu) change ide1-cd0 /path/to/some.iso |
format is optional.
(qemu) change vnc localhost:1 |
Change the password associated with the VNC server. If the new password is not supplied, the monitor will prompt for it to be entered. VNC passwords are only significant up to 8 letters. eg
(qemu) change vnc password Password: ******** |
fmt is a format which tells the command how to format the data. Its syntax is: `/{count}{format}{size}'
h or w can be specified with the i format to
respectively select 16 or 32 bit code instruction size.
Examples:
(qemu) x/10i $eip 0x90107063: ret 0x90107064: sti 0x90107065: lea 0x0(%esi,1),%esi 0x90107069: lea 0x0(%edi,1),%edi 0x90107070: ret 0x90107071: jmp 0x90107080 0x90107073: nop 0x90107074: nop 0x90107075: nop 0x90107076: nop |
(qemu) xp/80hx 0xb8000 0x000b8000: 0x0b50 0x0b6c 0x0b65 0x0b78 0x0b38 0x0b36 0x0b2f 0x0b42 0x000b8010: 0x0b6f 0x0b63 0x0b68 0x0b73 0x0b20 0x0b56 0x0b47 0x0b41 0x000b8020: 0x0b42 0x0b69 0x0b6f 0x0b73 0x0b20 0x0b63 0x0b75 0x0b72 0x000b8030: 0x0b72 0x0b65 0x0b6e 0x0b74 0x0b2d 0x0b63 0x0b76 0x0b73 0x000b8040: 0x0b20 0x0b30 0x0b35 0x0b20 0x0b4e 0x0b6f 0x0b76 0x0b20 0x000b8050: 0x0b32 0x0b30 0x0b30 0x0b33 0x0720 0x0720 0x0720 0x0720 0x000b8060: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x000b8070: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x000b8080: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 |
Print expression value. Only the format part of fmt is used. Read I/O port. Write to I/O port.
Send keys to the emulator. keys could be the name of the
key or # followed by the raw value in either decimal or hexadecimal
format. Use - to press several keys simultaneously. Example:
sendkey ctrl-alt-f1 |
This command is useful to send keys that your graphical user interface
intercepts at low level, such as ctrl-alt-f1 in X Window.
Reset the system.
Power down the system (if supported).
Compute the checksum of a memory region.
Add the USB device devname. For details of available devices see 3.9.1 Connecting USB devices
Remove the USB device devname from the QEMU virtual USB
hub. devname has the syntax bus.addr. Use the monitor
command info usb to see the devices you can remove.
Add device.
Remove device id. Set the default CPU.
info mice |
Defaults:
info capture |
Define new values for the boot device list. Those values will override
the values specified on the command line through the -boot option.
The values that can be specified here depend on the machine type, but are
the same that can be specified in the -boot command line option.
allow|deny'
deny.
allow|deny [index]'
*@EXAMPLE.COM to
allow all users in the EXAMPLE.COM kerberos realm. The match will
normally be appended to the end of the ACL, but can be inserted
earlier in the list if the optional index parameter is supplied.
deny.
getfd command. This is only needed if the file descriptor was never
used by another monitor command.
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The monitor understands integers expressions for every integer argument. You can use register names to get the value of specifics CPU registers by prefixing them with $.
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Since version 0.6.1, QEMU supports many disk image formats, including growable disk images (their size increase as non empty sectors are written), compressed and encrypted disk images. Version 0.8.3 added the new qcow2 disk image format which is essential to support VM snapshots.
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You can create a disk image with the command:
qemu-img create myimage.img mysize |
M suffix to give the size in
megabytes and a G suffix for gigabytes.
See 3.6.4 qemu-img Invocation for more information.
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If you use the option `-snapshot', all disk images are
considered as read only. When sectors in written, they are written in
a temporary file created in `/tmp'. You can however force the
write back to the raw disk images by using the commit monitor
command (or C-a s in the serial console).
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VM snapshots are snapshots of the complete virtual machine including
CPU state, RAM, device state and the content of all the writable
disks. In order to use VM snapshots, you must have at least one non
removable and writable block device using the qcow2 disk image
format. Normally this device is the first virtual hard drive.
Use the monitor command savevm to create a new VM snapshot or
replace an existing one. A human readable name can be assigned to each
snapshot in addition to its numerical ID.
Use loadvm to restore a VM snapshot and delvm to remove
a VM snapshot. info snapshots lists the available snapshots
with their associated information:
(qemu) info snapshots Snapshot devices: hda Snapshot list (from hda): ID TAG VM SIZE DATE VM CLOCK 1 start 41M 2006-08-06 12:38:02 00:00:14.954 2 40M 2006-08-06 12:43:29 00:00:18.633 3 msys 40M 2006-08-06 12:44:04 00:00:23.514 |
A VM snapshot is made of a VM state info (its size is shown in
info snapshots) and a snapshot of every writable disk image.
The VM state info is stored in the first qcow2 non removable
and writable block device. The disk image snapshots are stored in
every disk image. The size of a snapshot in a disk image is difficult
to evaluate and is not shown by info snapshots because the
associated disk sectors are shared among all the snapshots to save
disk space (otherwise each snapshot would need a full copy of all the
disk images).
When using the (unrelated) -snapshot option
(3.6.2 Snapshot mode), you can always make VM snapshots,
but they are deleted as soon as you exit QEMU.
VM snapshots currently have the following known limitations:
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qemu-img Invocation
usage: qemu-img command [command options] |
The following commands are supported:
Command parameters:
k or K
(kilobyte, 1024) M (megabyte, 1024k) and G (gigabyte, 1024M)
and T (terabyte, 1024G) are supported. b is ignored.
-o ? for an overview of the options supported
by the used format or see the format descriptions below for details.
Parameters to snapshot subcommand:
Command description:
Create the new disk image filename of size size and format fmt. Depending on the file format, you can add one or more options that enable additional features of this format.
If the option backing_file is specified, then the image will record
only the differences from backing_file. No size needs to be specified in
this case. backing_file will never be modified unless you use the
commit monitor command (or qemu-img commit).
The size can also be specified using the size option with -o,
it doesn't need to be specified separately in this case.
Commit the changes recorded in filename in its base image.
Convert the disk image filename to disk image output_filename
using format output_fmt. It can be optionally compressed (-c
option) or use any format specific options like encryption (-o option).
Only the formats qcow and qcow2 support compression. The
compression is read-only. It means that if a compressed sector is
rewritten, then it is rewritten as uncompressed data.
Image conversion is also useful to get smaller image when using a
growable format such as qcow or cow: the empty sectors
are detected and suppressed from the destination image.
You can use the backing_file option to force the output image to be created as a copy on write image of the specified base image; the backing_file should have the same content as the input's base image, however the path, image format, etc may differ.
Give information about the disk image filename. Use it in particular to know the size reserved on disk which can be different from the displayed size. If VM snapshots are stored in the disk image, they are displayed too.
List, apply, create or delete snapshots in image filename.
Supported image file formats:
Raw disk image format (default). This format has the advantage of
being simple and easily exportable to all other emulators. If your
file system supports holes (for example in ext2 or ext3 on
Linux or NTFS on Windows), then only the written sectors will reserve
space. Use qemu-img info to know the real size used by the
image or ls -ls on Unix/Linux.
Host device format. This format should be used instead of raw when converting to block devices or other devices where "holes" are not supported.
Supported options:
backing_file
backing_fmt
encryption
on, the image is encrypted.
Encryption uses the AES format which is very secure (128 bit keys). Use a long password (16 characters) to get maximum protection.
cluster_size
preallocation
Supported options:
backing_file
encryption
on, the image is encrypted.
Supported options:
backing_fmt
compat6
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qemu-nbd Invocation
usage: qemu-nbd [OPTION]... filename |
Export Qemu disk image using NBD protocol.
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In addition to disk image files, QEMU can directly access host devices. We describe here the usage for QEMU version >= 0.8.3.
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On Linux, you can directly use the host device filename instead of a disk image filename provided you have enough privileges to access it. For example, use `/dev/cdrom' to access to the CDROM or `/dev/fd0' for the floppy.
CD
Floppy
Hard disks
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CD
Currently there is no specific code to handle removable media, so it
is better to use the change or eject monitor commands to
change or eject media.
Hard disks
WARNING: unless you know what you do, it is better to only make READ-ONLY accesses to the hard disk otherwise you may corrupt your host data (use the `-snapshot' command line so that the modifications are written in a temporary file).
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`/dev/cdrom' is an alias to the first CDROM.
Currently there is no specific code to handle removable media, so it
is better to use the change or eject monitor commands to
change or eject media.
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QEMU can automatically create a virtual FAT disk image from a directory tree. In order to use it, just type:
qemu linux.img -hdb fat:/my_directory |
Then you access access to all the files in the `/my_directory' directory without having to copy them in a disk image or to export them via SAMBA or NFS. The default access is read-only.
Floppies can be emulated with the :floppy: option:
qemu linux.img -fda fat:floppy:/my_directory |
A read/write support is available for testing (beta stage) with the
:rw: option:
qemu linux.img -fda fat:floppy:rw:/my_directory |
What you should never do:
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QEMU can access directly to block device exported using the Network Block Device protocol.
qemu linux.img -hdb nbd:my_nbd_server.mydomain.org:1024 |
If the NBD server is located on the same host, you can use an unix socket instead of an inet socket:
qemu linux.img -hdb nbd:unix:/tmp/my_socket |
In this case, the block device must be exported using qemu-nbd:
qemu-nbd --socket=/tmp/my_socket my_disk.qcow2 |
The use of qemu-nbd allows to share a disk between several guests:
qemu-nbd --socket=/tmp/my_socket --share=2 my_disk.qcow2 |
and then you can use it with two guests:
qemu linux1.img -hdb nbd:unix:/tmp/my_socket qemu linux2.img -hdb nbd:unix:/tmp/my_socket |
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QEMU can simulate several network cards (PCI or ISA cards on the PC target) and can connect them to an arbitrary number of Virtual Local Area Networks (VLANs). Host TAP devices can be connected to any QEMU VLAN. VLAN can be connected between separate instances of QEMU to simulate large networks. For simpler usage, a non privileged user mode network stack can replace the TAP device to have a basic network connection.
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QEMU simulates several VLANs. A VLAN can be symbolised as a virtual connection between several network devices. These devices can be for example QEMU virtual Ethernet cards or virtual Host ethernet devices (TAP devices).
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This is the standard way to connect QEMU to a real network. QEMU adds
a virtual network device on your host (called tapN), and you
can then configure it as if it was a real ethernet card.
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As an example, you can download the `linux-test-xxx.tar.gz'
archive and copy the script `qemu-ifup' in `/etc' and
configure properly sudo so that the command ifconfig
contained in `qemu-ifup' can be executed as root. You must verify
that your host kernel supports the TAP network interfaces: the
device `/dev/net/tun' must be present.
See 3.3 Invocation to have examples of command lines using the TAP network interfaces.
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There is a virtual ethernet driver for Windows 2000/XP systems, called TAP-Win32. But it is not included in standard QEMU for Windows, so you will need to get it separately. It is part of OpenVPN package, so download OpenVPN from : http://openvpn.net/.
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By using the option `-net user' (default configuration if no `-net' option is specified), QEMU uses a completely user mode network stack (you don't need root privilege to use the virtual network). The virtual network configuration is the following:
QEMU VLAN <------> Firewall/DHCP server <-----> Internet
| (10.0.2.2)
|
----> DNS server (10.0.2.3)
|
----> SMB server (10.0.2.4)
|
The QEMU VM behaves as if it was behind a firewall which blocks all incoming connections. You can use a DHCP client to automatically configure the network in the QEMU VM. The DHCP server assign addresses to the hosts starting from 10.0.2.15.
In order to check that the user mode network is working, you can ping the address 10.0.2.2 and verify that you got an address in the range 10.0.2.x from the QEMU virtual DHCP server.
Note that ping is not supported reliably to the internet as it
would require root privileges. It means you can only ping the local
router (10.0.2.2).
When using the built-in TFTP server, the router is also the TFTP server.
When using the `-redir' option, TCP or UDP connections can be redirected from the host to the guest. It allows for example to redirect X11, telnet or SSH connections.
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Using the `-net socket' option, it is possible to make VLANs that span several QEMU instances. See 3.3 Invocation to have a basic example.
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This section explains how to launch a Linux kernel inside QEMU without having to make a full bootable image. It is very useful for fast Linux kernel testing.
The syntax is:
qemu -kernel arch/i386/boot/bzImage -hda root-2.4.20.img -append "root=/dev/hda" |
Use `-kernel' to provide the Linux kernel image and `-append' to give the kernel command line arguments. The `-initrd' option can be used to provide an INITRD image.
When using the direct Linux boot, a disk image for the first hard disk `hda' is required because its boot sector is used to launch the Linux kernel.
If you do not need graphical output, you can disable it and redirect the virtual serial port and the QEMU monitor to the console with the `-nographic' option. The typical command line is:
qemu -kernel arch/i386/boot/bzImage -hda root-2.4.20.img \
-append "root=/dev/hda console=ttyS0" -nographic
|
Use Ctrl-a c to switch between the serial console and the monitor (see section 3.4 Keys).
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QEMU emulates a PCI UHCI USB controller. You can virtually plug virtual USB devices or real host USB devices (experimental, works only on Linux hosts). Qemu will automatically create and connect virtual USB hubs as necessary to connect multiple USB devices.
3.9.1 Connecting USB devices 3.9.2 Using host USB devices on a Linux host
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USB devices can be connected with the `-usbdevice' commandline option
or the usb_add monitor command. Available devices are:
mouse
tablet
disk:file
host:bus.addr
host:vendor_id:product_id
wacom-tablet
tablet
above but it can be used with the tslib library because in addition to touch
coordinates it reports touch pressure.
keyboard
serial:[vendorid=vendor_id][,product_id=product_id]:dev
-serial option. The vendorid and productid options can be
used to override the default 0403:6001. For instance,
usb_add serial:productid=FA00:tcp:192.168.0.2:4444 |
braille
net:options
-net nic,options (see description).
For instance, user-mode networking can be used with
qemu [...OPTIONS...] -net user,vlan=0 -usbdevice net:vlan=0 |
bt[:hci-type]
-bt hci,vlan=0.
This USB device implements the USB Transport Layer of HCI. Example
usage:
qemu [...OPTIONS...] -usbdevice bt:hci,vlan=3 -bt device:keyboard,vlan=3 |
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WARNING: this is an experimental feature. QEMU will slow down when using it. USB devices requiring real time streaming (i.e. USB Video Cameras) are not supported yet.
ls /proc/bus/usb 001 devices drivers |
chown -R myuid /proc/bus/usb |
info usbhost
Device 1.2, speed 480 Mb/s
Class 00: USB device 1234:5678, USB DISK
|
usb_add host:1234:5678 |
Normally the guest OS should report that a new USB device is plugged. You can use the option `-usbdevice' to do the same.
When relaunching QEMU, you may have to unplug and plug again the USB device to make it work again (this is a bug).
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The VNC server capability provides access to the graphical console of the guest VM across the network. This has a number of security considerations depending on the deployment scenarios.
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The simplest VNC server setup does not include any form of authentication. For this setup it is recommended to restrict it to listen on a UNIX domain socket only. For example
qemu [...OPTIONS...] -vnc unix:/home/joebloggs/.qemu-myvm-vnc |
This ensures that only users on local box with read/write access to that path can access the VNC server. To securely access the VNC server from a remote machine, a combination of netcat+ssh can be used to provide a secure tunnel.
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The VNC protocol has limited support for password based authentication. Since
the protocol limits passwords to 8 characters it should not be considered
to provide high security. The password can be fairly easily brute-forced by
a client making repeat connections. For this reason, a VNC server using password
authentication should be restricted to only listen on the loopback interface
or UNIX domain sockets. Password authentication is requested with the password
option, and then once QEMU is running the password is set with the monitor. Until
the monitor is used to set the password all clients will be rejected.
qemu [...OPTIONS...] -vnc :1,password -monitor stdio (qemu) change vnc password Password: ******** (qemu) |
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The QEMU VNC server also implements the VeNCrypt extension allowing use of TLS for encryption of the session, and x509 certificates for authentication. The use of x509 certificates is strongly recommended, because TLS on its own is susceptible to man-in-the-middle attacks. Basic x509 certificate support provides a secure session, but no authentication. This allows any client to connect, and provides an encrypted session.
qemu [...OPTIONS...] -vnc :1,tls,x509=/etc/pki/qemu -monitor stdio |
In the above example /etc/pki/qemu should contain at least three files,
ca-cert.pem, server-cert.pem and server-key.pem. Unprivileged
users will want to use a private directory, for example $HOME/.pki/qemu.
NB the server-key.pem file should be protected with file mode 0600 to
only be readable by the user owning it.
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Certificates can also provide a means to authenticate the client connecting. The server will request that the client provide a certificate, which it will then validate against the CA certificate. This is a good choice if deploying in an environment with a private internal certificate authority.
qemu [...OPTIONS...] -vnc :1,tls,x509verify=/etc/pki/qemu -monitor stdio |
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Finally, the previous method can be combined with VNC password authentication to provide two layers of authentication for clients.
qemu [...OPTIONS...] -vnc :1,password,tls,x509verify=/etc/pki/qemu -monitor stdio (qemu) change vnc password Password: ******** (qemu) |
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The SASL authentication method is a VNC extension, that provides an easily extendable, pluggable authentication method. This allows for integration with a wide range of authentication mechanisms, such as PAM, GSSAPI/Kerberos, LDAP, SQL databases, one-time keys and more. The strength of the authentication depends on the exact mechanism configured. If the chosen mechanism also provides a SSF layer, then it will encrypt the datastream as well.
Refer to the later docs on how to choose the exact SASL mechanism used for authentication, but assuming use of one supporting SSF, then QEMU can be launched with:
qemu [...OPTIONS...] -vnc :1,sasl -monitor stdio |
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If the desired SASL authentication mechanism does not supported SSF layers, then it is strongly advised to run it in combination with TLS and x509 certificates. This provides securely encrypted data stream, avoiding risk of compromising of the security credentials. This can be enabled, by combining the 'sasl' option with the aforementioned TLS + x509 options:
qemu [...OPTIONS...] -vnc :1,tls,x509,sasl -monitor stdio |
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The GNU TLS packages provides a command called certtool which can
be used to generate certificates and keys in PEM format. At a minimum it
is neccessary to setup a certificate authority, and issue certificates to
each server. If using certificates for authentication, then each client
will also need to be issued a certificate. The recommendation is for the
server to keep its certificates in either /etc/pki/qemu or for
unprivileged users in $HOME/.pki/qemu.
3.10.8.1 Setup the Certificate Authority 3.10.8.2 Issuing server certificates 3.10.8.3 Issuing client certificates
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This step only needs to be performed once per organization / organizational unit. First the CA needs a private key. This key must be kept VERY secret and secure. If this key is compromised the entire trust chain of the certificates issued with it is lost.
# certtool --generate-privkey > ca-key.pem |
A CA needs to have a public certificate. For simplicity it can be a self-signed certificate, or one issue by a commercial certificate issuing authority. To generate a self-signed certificate requires one core piece of information, the name of the organization.
# cat > ca.info <<EOF
cn = Name of your organization
ca
cert_signing_key
EOF
# certtool --generate-self-signed \
--load-privkey ca-key.pem
--template ca.info \
--outfile ca-cert.pem
|
The ca-cert.pem file should be copied to all servers and clients wishing to utilize
TLS support in the VNC server. The ca-key.pem must not be disclosed/copied at all.
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Each server (or host) needs to be issued with a key and certificate. When connecting the certificate is sent to the client which validates it against the CA certificate. The core piece of information for a server certificate is the hostname. This should be the fully qualified hostname that the client will connect with, since the client will typically also verify the hostname in the certificate. On the host holding the secure CA private key:
# cat > server.info <<EOF
organization = Name of your organization
cn = server.foo.example.com
tls_www_server
encryption_key
signing_key
EOF
# certtool --generate-privkey > server-key.pem
# certtool --generate-certificate \
--load-ca-certificate ca-cert.pem \
--load-ca-privkey ca-key.pem \
--load-privkey server server-key.pem \
--template server.info \
--outfile server-cert.pem
|
The server-key.pem and server-cert.pem files should now be securely copied
to the server for which they were generated. The server-key.pem is security
sensitive and should be kept protected with file mode 0600 to prevent disclosure.
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If the QEMU VNC server is to use the x509verify option to validate client
certificates as its authentication mechanism, each client also needs to be issued
a certificate. The client certificate contains enough metadata to uniquely identify
the client, typically organization, state, city, building, etc. On the host holding
the secure CA private key:
# cat > client.info <<EOF
country = GB
state = London
locality = London
organiazation = Name of your organization
cn = client.foo.example.com
tls_www_client
encryption_key
signing_key
EOF
# certtool --generate-privkey > client-key.pem
# certtool --generate-certificate \
--load-ca-certificate ca-cert.pem \
--load-ca-privkey ca-key.pem \
--load-privkey client-key.pem \
--template client.info \
--outfile client-cert.pem
|
The client-key.pem and client-cert.pem files should now be securely
copied to the client for which they were generated.
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The following documentation assumes use of the Cyrus SASL implementation on a Linux host, but the principals should apply to any other SASL impl. When SASL is enabled, the mechanism configuration will be loaded from system default SASL service config /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, an environment variable SASL_CONF_PATH can be used to make it search alternate locations for the service config.
The default configuration might contain
mech_list: digest-md5 sasldb_path: /etc/qemu/passwd.db |
This says to use the 'Digest MD5' mechanism, which is similar to the HTTP Digest-MD5 mechanism. The list of valid usernames & passwords is maintained in the /etc/qemu/passwd.db file, and can be updated using the saslpasswd2 command. While this mechanism is easy to configure and use, it is not considered secure by modern standards, so only suitable for developers / ad-hoc testing.
A more serious deployment might use Kerberos, which is done with the 'gssapi' mechanism
mech_list: gssapi keytab: /etc/qemu/krb5.tab |
For this to work the administrator of your KDC must generate a Kerberos principal for the server, with a name of 'qemu/somehost.example.com@EXAMPLE.COM' replacing 'somehost.example.com' with the fully qualified host name of the machine running QEMU, and 'EXAMPLE.COM' with the Keberos Realm.
Other configurations will be left as an exercise for the reader. It should be noted that only Digest-MD5 and GSSAPI provides a SSF layer for data encryption. For all other mechanisms, VNC should always be configured to use TLS and x509 certificates to protect security credentials from snooping.
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QEMU has a primitive support to work with gdb, so that you can do 'Ctrl-C' while the virtual machine is running and inspect its state.
In order to use gdb, launch qemu with the '-s' option. It will wait for a gdb connection:
> qemu -s -kernel arch/i386/boot/bzImage -hda root-2.4.20.img \
-append "root=/dev/hda"
Connected to host network interface: tun0
Waiting gdb connection on port 1234
|
Then launch gdb on the 'vmlinux' executable:
> gdb vmlinux |
In gdb, connect to QEMU:
(gdb) target remote localhost:1234 |
Then you can use gdb normally. For example, type 'c' to launch the kernel:
(gdb) c |
Here are some useful tips in order to use gdb on system code:
info reg to display all the CPU registers.
x/10i $eip to display the code at the PC position.
set architecture i8086 to dump 16 bit code. Then use
x/10i $cs*16+$eip to dump the code at the PC position.
Advanced debugging options:
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 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:
maintenance packet qqemu.sstepbits
This will display the MASK bits used to control the single stepping IE:
(gdb) maintenance packet qqemu.sstepbits sending: "qqemu.sstepbits" received: "ENABLE=1,NOIRQ=2,NOTIMER=4" |
maintenance packet qqemu.sstep
This will display the current value of the mask used when single stepping IE:
(gdb) maintenance packet qqemu.sstep sending: "qqemu.sstep" received: "0x7" |
maintenance packet Qqemu.sstep=HEX_VALUE
This will change the single step mask, so if wanted to enable IRQs on the single step, but not timers, you would use:
(gdb) maintenance packet Qqemu.sstep=0x5 sending: "qemu.sstep=0x5" received: "OK" |
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To have access to SVGA graphic modes under X11, use the vesa or
the cirrus X11 driver. For optimal performances, use 16 bit
color depth in the guest and the host OS.
When using a 2.6 guest Linux kernel, you should add the option
clock=pit on the kernel command line because the 2.6 Linux
kernels make very strict real time clock checks by default that QEMU
cannot simulate exactly.
When using a 2.6 guest Linux kernel, verify that the 4G/4G patch is not activated because QEMU is slower with this patch. The QEMU Accelerator Module is also much slower in this case. Earlier Fedora Core 3 Linux kernel (< 2.6.9-1.724_FC3) were known to incorporate this patch by default. Newer kernels don't have it.
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If you have a slow host, using Windows 95 is better as it gives the best speed. Windows 2000 is also a good choice.
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QEMU emulates a Cirrus Logic GD5446 Video card. All Windows versions starting from Windows 95 should recognize and use this graphic card. For optimal performances, use 16 bit color depth in the guest and the host OS.
If you are using Windows XP as guest OS and if you want to use high resolution modes which the Cirrus Logic BIOS does not support (i.e. >= 1280x1024x16), then you should use the VESA VBE virtual graphic card (option `-std-vga').
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Windows 9x does not correctly use the CPU HLT instruction. The result is that it takes host CPU cycles even when idle. You can install the utility from http://www.user.cityline.ru/~maxamn/amnhltm.zip to solve this problem. Note that no such tool is needed for NT, 2000 or XP.
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Windows 2000 has a bug which gives a disk full problem during its installation. When installing it, use the `-win2k-hack' QEMU option to enable a specific workaround. After Windows 2000 is installed, you no longer need this option (this option slows down the IDE transfers).
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Windows 2000 cannot automatically shutdown in QEMU although Windows 98 can. It comes from the fact that Windows 2000 does not automatically use the APM driver provided by the BIOS.
In order to correct that, do the following (thanks to Struan Bartlett): go to the Control Panel => Add/Remove Hardware & Next => Add/Troubleshoot a device => Add a new device & Next => No, select the hardware from a list & Next => NT Apm/Legacy Support & Next => Next (again) a few times. Now the driver is installed and Windows 2000 now correctly instructs QEMU to shutdown at the appropriate moment.
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See 3.3 Invocation about the help of the option `-smb'.
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Some releases of Windows XP install correctly but give a security error when booting:
A problem is preventing Windows from accurately checking the license for this computer. Error code: 0x800703e6. |
The workaround is to install a service pack for XP after a boot in safe mode. Then reboot, and the problem should go away. Since there is no network while in safe mode, its recommended to download the full installation of SP1 or SP2 and transfer that via an ISO or using the vvfat block device ("-hdb fat:directory_which_holds_the_SP").
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DOS does not correctly use the CPU HLT instruction. The result is that it takes host CPU cycles even when idle. You can install the utility from http://www.vmware.com/software/dosidle210.zip to solve this problem.
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QEMU is a generic emulator and it emulates many non PC machines. Most of the options are similar to the PC emulator. The differences are mentioned in the following sections.
4.1 QEMU PowerPC System emulator 4.2 Sparc32 System emulator 4.3 Sparc64 System emulator 4.4 MIPS System emulator 4.5 ARM System emulator 4.6 ColdFire System emulator
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Use the executable `qemu-system-ppc' to simulate a complete PREP or PowerMac PowerPC system.
QEMU emulates the following PowerMac peripherals:
QEMU emulates the following PREP peripherals:
QEMU uses the Open Hack'Ware Open Firmware Compatible BIOS available at http://perso.magic.fr/l_indien/OpenHackWare/index.htm.
Since version 0.9.1, QEMU uses OpenBIOS http://www.openbios.org/ for the g3beige and mac99 PowerMac machines. OpenBIOS is a free (GPL v2) portable firmware implementation. The goal is to implement a 100% IEEE 1275-1994 (referred to as Open Firmware) compliant firmware.
The following options are specific to the PowerPC emulation:
Set the initial VGA graphic mode. The default is 800x600x15.
Set OpenBIOS variables in NVRAM, for example:
qemu-system-ppc -prom-env 'auto-boot?=false' \ -prom-env 'boot-device=hd:2,\yaboot' \ -prom-env 'boot-args=conf=hd:2,\yaboot.conf' |
These variables are not used by Open Hack'Ware.
More information is available at http://perso.magic.fr/l_indien/qemu-ppc/.
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Use the executable `qemu-system-sparc' to simulate the following Sun4m architecture machines:
The emulation is somewhat complete. SMP up to 16 CPUs is supported, but Linux limits the number of usable CPUs to 4.
It's also possible to simulate a SPARCstation 2 (sun4c architecture), SPARCserver 1000, or SPARCcenter 2000 (sun4d architecture), but these emulators are not usable yet.
QEMU emulates the following sun4m/sun4c/sun4d peripherals:
The number of peripherals is fixed in the architecture. Maximum memory size depends on the machine type, for SS-5 it is 256MB and for others 2047MB.
Since version 0.8.2, QEMU uses OpenBIOS http://www.openbios.org/. OpenBIOS is a free (GPL v2) portable firmware implementation. The goal is to implement a 100% IEEE 1275-1994 (referred to as Open Firmware) compliant firmware.
A sample Linux 2.6 series kernel and ram disk image are available on the QEMU web site. There are still issues with NetBSD and OpenBSD, but some kernel versions work. Please note that currently Solaris kernels don't work probably due to interface issues between OpenBIOS and Solaris.
The following options are specific to the Sparc32 emulation:
Set the initial TCX graphic mode. The default is 1024x768x8, currently the only other possible mode is 1024x768x24.
Set OpenBIOS variables in NVRAM, for example:
qemu-system-sparc -prom-env 'auto-boot?=false' \ -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' |
Set the emulated machine type. Default is SS-5.
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Use the executable `qemu-system-sparc64' to simulate a Sun4u (UltraSPARC PC-like machine), Sun4v (T1 PC-like machine), or generic Niagara (T1) machine. The emulator is not usable for anything yet, but it can launch some kernels.
QEMU emulates the following peripherals:
The following options are specific to the Sparc64 emulation:
Set OpenBIOS variables in NVRAM, for example:
qemu-system-sparc64 -prom-env 'auto-boot?=false' |
Set the emulated machine type. The default is sun4u.
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Four executables cover simulation of 32 and 64-bit MIPS systems in both endian options, `qemu-system-mips', `qemu-system-mipsel' `qemu-system-mips64' and `qemu-system-mips64el'. Five different machine types are emulated:
The generic emulation is supported by Debian 'Etch' and is able to install Debian into a virtual disk image. The following devices are emulated:
The Malta emulation supports the following devices:
The ACER Pica emulation supports:
The mipssim pseudo board emulation provides an environment similiar to what the proprietary MIPS emulator uses for running Linux. It supports:
The MIPS Magnum R4000 emulation supports:
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Use the executable `qemu-system-arm' to simulate a ARM machine. The ARM Integrator/CP board is emulated with the following devices:
The ARM Versatile baseboard is emulated with the following devices:
The ARM RealView Emulation/Platform baseboard is emulated with the following devices:
The XScale-based clamshell PDA models ("Spitz", "Akita", "Borzoi" and "Terrier") emulation includes the following peripherals:
The Palm Tungsten|E PDA (codename "Cheetah") emulation includes the following elements:
Nokia N800 and N810 internet tablets (known also as RX-34 and RX-44 / 48) emulation supports the following elements:
The Luminary Micro Stellaris LM3S811EVB emulation includes the following devices:
The Luminary Micro Stellaris LM3S6965EVB emulation includes the following devices:
The Freecom MusicPal internet radio emulation includes the following elements:
The Siemens SX1 models v1 and v2 (default) basic emulation. The emulaton includes the following elements:
The "Syborg" Symbian Virtual Platform base model includes the following elements:
A Linux 2.6 test image is available on the QEMU web site. More information is available in the QEMU mailing-list archive.
The following options are specific to the ARM emulation:
On ARM this implements the "Angel" interface.
Note that this allows guest direct access to the host filesystem, so should only be used with trusted guest OS.
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Use the executable `qemu-system-m68k' to simulate a ColdFire machine. The emulator is able to boot a uClinux kernel.
The M5208EVB emulation includes the following devices:
The AN5206 emulation includes the following devices:
The following options are specific to the ARM emulation:
On M68K this implements the "ColdFire GDB" interface used by libgloss.
Note that this allows guest direct access to the host filesystem, so should only be used with trusted guest OS.
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5.1 Supported Operating Systems 5.2 Linux User space emulator 5.3 Mac OS X/Darwin User space emulator 5.4 BSD User space emulator
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The following OS are supported in user space emulation:
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5.2.1 Quick Start 5.2.2 Wine launch 5.2.3 Command line options 5.2.4 Other binaries
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In order to launch a Linux process, QEMU needs the process executable itself and all the target (x86) dynamic libraries used by it.
qemu-i386 -L / /bin/ls |
-L / tells that the x86 dynamic linker must be searched with a
`/' prefix.
qemu-i386 -L / qemu-i386 -L / /bin/ls |
LD_LIBRARY_PATH is not set:
unset LD_LIBRARY_PATH |
Then you can launch the precompiled `ls' x86 executable:
qemu-i386 tests/i386/ls |
binfmt_misc module in the
Linux kernel.
qemu-i386 /usr/local/qemu-i386/bin/qemu-i386 \
/usr/local/qemu-i386/bin/ls-i386
|
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qemu-i386 /usr/local/qemu-i386/bin/ls-i386 |
${HOME}/.wine directory is saved to ${HOME}/.wine.org.
qemu-i386 /usr/local/qemu-i386/wine/bin/wine \
/usr/local/qemu-i386/wine/c/Program\ Files/putty.exe
|
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usage: qemu-i386 [-h] [-d] [-L path] [-s size] [-cpu model] [-g port] [-B offset] program [arguments...] |
Debug options:
Environment variables:
QEMU_STRACE
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qemu-arm is also capable of running ARM "Angel" semihosted ELF
binaries (as implemented by the arm-elf and arm-eabi Newlib/GDB
configurations), and arm-uclinux bFLT format binaries.
qemu-m68k is capable of running semihosted binaries using the BDM
(m5xxx-ram-hosted.ld) or m68k-sim (sim.ld) syscall interfaces, and
coldfire uClinux bFLT format binaries.
The binary format is detected automatically.
qemu-sparc can execute Sparc32 binaries (Sparc32 CPU, 32 bit ABI).
qemu-sparc32plus can execute Sparc32 and SPARC32PLUS binaries
(Sparc64 CPU, 32 bit ABI).
qemu-sparc64 can execute some Sparc64 (Sparc64 CPU, 64 bit ABI) and
SPARC32PLUS binaries (Sparc64 CPU, 32 bit ABI).
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5.3.1 Mac OS X/Darwin Status 5.3.2 Quick Start 5.3.3 Command line options
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[1] If you're host commpage can be executed by qemu.
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In order to launch a Mac OS X/Darwin process, QEMU needs the process executable itself and all the target dynamic libraries used by it. If you don't have the FAT libraries (you're running Mac OS X/ppc) you'll need to obtain it from a Mac OS X CD or compile them by hand.
qemu-i386 /bin/ls |
or to run the ppc version of the executable:
qemu-ppc /bin/ls |
qemu-i386 -L /opt/x86_root/ /bin/ls |
-L /opt/x86_root/ tells that the dynamic linker (dyld) path is in
`/opt/x86_root/usr/bin/dyld'.
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usage: qemu-i386 [-h] [-d] [-L path] [-s size] program [arguments...] |
Debug options:
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5.4.1 BSD Status 5.4.2 Quick Start 5.4.3 Command line options
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In order to launch a BSD process, QEMU needs the process executable itself and all the target dynamic libraries used by it.
qemu-sparc64 /bin/ls |
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usage: qemu-sparc64 [-h] [-d] [-L path] [-s size] [-bsd type] program [arguments...] |
Debug options:
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6.1 Linux/Unix 6.2 Windows 6.3 Cross compilation for Windows with Linux 6.4 Mac OS X
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First you must decompress the sources:
cd /tmp tar zxvf qemu-x.y.z.tar.gz cd qemu-x.y.z |
Then you configure QEMU and build it (usually no options are needed):
./configure make |
Then type as root user:
make install |
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./configure --enable-mingw32 |
Note: Currently, Wine does not seem able to launch QEMU for Win32.
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The Mac OS X patches are not fully merged in QEMU, so you should look at the QEMU mailing list archive to have all the necessary information.
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qemu-img Invocation
qemu-nbd Invocation
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1. Introduction
2. Installation
3. QEMU PC System emulator
4. QEMU System emulator for non PC targets
5. QEMU User space emulator
6. Compilation from the sources
7. Index
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