QEMU(1) QEMU(1)
NAME
qemu-doc - QEMU Emulator User Documentation
SYNOPSIS
usage: qemu [options] [disk_image]
DESCRIPTION
The QEMU PC System emulator simulates the following peripherals:
- i440FX host PCI bridge and PIIX3 PCI to ISA bridge
- Cirrus CLGD 5446 PCI VGA card or dummy VGA card with Bochs VESA
extensions (hardware level, including all non standard modes).
- PS/2 mouse and keyboard
- 2 PCI IDE interfaces with hard disk and CD-ROM support
- Floppy disk
- NE2000 PCI network adapters
- Serial ports
- Creative SoundBlaster 16 sound card
- ENSONIQ AudioPCI ES1370 sound card
- Adlib(OPL2) - Yamaha YM3812 compatible chip
- PCI UHCI USB controller and a virtual USB hub.
SMP is supported with up to 255 CPUs.
Note that adlib is only available when QEMU was configured with
-enable-adlib
QEMU uses the PC BIOS from the Bochs project and the Plex86/Bochs LGPL
VGA BIOS.
QEMU uses YM3812 emulation by Tatsuyuki Satoh.
OPTIONS
disk_image is a raw hard disk image for IDE hard disk 0.
General options:
-M machine
Select the emulated machine ("-M ?" for list)
-fda file
-fdb file
Use file as floppy disk 0/1 image. You can use the host floppy by
using /dev/fd0 as filename.
-hda file
-hdb file
-hdc file
-hdd file
Use file as hard disk 0, 1, 2 or 3 image.
-cdrom file
Use file as CD-ROM image (you cannot use -hdc and and -cdrom at the
same time). You can use the host CD-ROM by using /dev/cdrom as
filename.
-boot [a│c│d│n]
Boot on floppy (a), hard disk (c), CD-ROM (d), or Etherboot (n).
Hard disk boot is the default.
-snapshot
Write to temporary files instead of disk image files. In this case,
the raw disk image you use is not written back. You can however
force the write back by pressing C-a s.
-no-fd-bootchk
Disable boot signature checking for floppy disks in Bochs BIOS. It
may be needed to boot from old floppy disks.
-m megs
Set virtual RAM size to megs megabytes. Default is 128 MB.
-smp n
Simulate an SMP system with n CPUs. On the PC target, up to 255
CPUs are supported.
-nographic
Normally, QEMU uses SDL to display the VGA output. With this
option, you can totally disable graphical output so that QEMU is a
simple command line application. The emulated serial port is redi-
rected on the console. Therefore, you can still use QEMU to debug a
Linux kernel with a serial console.
-vnc display
Normally, QEMU uses SDL to display the VGA output. With this
option, you can have QEMU listen on VNC display display and redi-
rect the VGA display over the VNC session. It is very useful to
enable the usb tablet device when using this option (option -usbde-
vice tablet). When using the VNC display, you must use the -k
option to set the keyboard layout if you are not using en-us.
display may be in the form interface:d, in which case connections
will only be allowed from interface on display d. Optionally,
interface can be omitted. display can also be in the form
unix:path where path is the location of a unix socket to listen for
connections on.
-k language
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".
-audio-help
Will show the audio subsystem help: list of drivers, tunable param-
eters.
-soundhw card1,card2,... or -soundhw all
Enable audio and selected sound hardware. Use ? to print all avail-
able sound hardware.
qemu -soundhw sb16,adlib hda
qemu -soundhw es1370 hda
qemu -soundhw all hda
qemu -soundhw ?
-localtime
Set the real time clock to local time (the default is to UTC time).
This option is needed to have correct date in MS-DOS or Windows.
-full-screen
Start in full screen.
-pidfile file
Store the QEMU process PID in file. It is useful if you launch QEMU
from a script.
-daemonize
Daemonize the QEMU process after initialization. QEMU will not
detach from standard IO until it is ready to receive connections on
any of its devices. This option is a useful way for external pro-
grams to launch QEMU without having to cope with initialization
race conditions.
-win2k-hack
Use it when installing Windows 2000 to avoid a disk full bug. After
Windows 2000 is installed, you no longer need this option (this
option slows down the IDE transfers).
-option-rom file
Load the contents of file as an option ROM. This option is useful
to load things like EtherBoot.
USB options:
-usb
Enable the USB driver (will be the default soon)
-usbdevice devname
Add the USB device devname.
Network options:
-net nic[,vlan=n][,macaddr=addr][,model=type]
Create a new Network Interface Card and connect it to VLAN n (n = 0
is the default). The NIC is currently an NE2000 on the PC target.
Optionally, the MAC address can be changed. If no -net option is
specified, a single NIC is created. Qemu can emulate several dif-
ferent models of network card. Valid values for type are
"ne2k_pci", "ne2k_isa", "rtl8139", "smc91c111" and "lance". Not
all devices are supported on all targets.
-net user[,vlan=n][,hostname=name]
Use the user mode network stack which requires no administrator
priviledge to run. hostname=name can be used to specify the client
hostname reported by the builtin DHCP server.
-net tap[,vlan=n][,fd=h][,ifname=name][,script=file]
Connect the host TAP network interface name to VLAN n and use the
network script file to configure it. The default network script is
/etc/qemu-ifup. Use script=no to disable script execution. If name
is not provided, the OS automatically provides one. fd=h can be
used to specify the handle of an already opened host TAP interface.
Example:
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
-net socket[,vlan=n][,fd=h][,listen=[host]:port][,connect=host:port]
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
-net socket[,vlan=n][,fd=h][,mcast=maddr:port]
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:
1. Several QEMU can be running on different hosts and share same
bus (assuming correct multicast setup for these hosts).
2. mcast support is compatible with User Mode Linux (argument
ethN=mcast), see <http://user-mode-linux.sf.net>.
3.<Use fd=h to specify an already opened UDP multicast socket.>
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
-net none
Indicate that no network devices should be configured. It is used
to override the default configuration (-net nic -net user) which is
activated if no -net options are provided.
-tftp prefix
When using the user mode network stack, activate a built-in TFTP
server. All filenames beginning with prefix can be downloaded from
the host to the guest using a TFTP client. The TFTP client on the
guest must be configured in binary mode (use the command "bin" of
the Unix TFTP client). The host IP address on the guest is as usual
10.0.2.2.
-smb dir
When using the user mode network stack, activate a built-in SMB
server so that Windows OSes can access to the host files in dir
transparently.
In the guest Windows OS, the line:
10.0.2.4 smbserver
must be added in the file C:\WINDOWS\LMHOSTS (for windows 9x/Me) or
C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS (Windows NT/2000).
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 version
2.2.7a from the Red Hat 9 and version 3.0.10-1.fc3 from Fedora Core
3.
-redir [tcp│udp]:host-port:[guest-host]:guest-port
When using the user mode network stack, redirect incoming TCP or
UDP connections to the host port host-port to the guest guest-host
on guest port guest-port. If guest-host is not specified, its value
is 10.0.2.15 (default address given by the built-in DHCP server).
For example, to redirect host X11 connection from screen 1 to guest
screen 0, use the following:
# on the host
qemu -redir tcp: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 -redir tcp:5555::23 [...]
telnet localhost 5555
Then when you use on the host "telnet localhost 5555", you connect
to the guest telnet server.
Linux boot specific: When using these options, you can use a given
Linux kernel without installing it in the disk image. It can be useful
for easier testing of various kernels.
-kernel bzImage
Use bzImage as kernel image.
-append cmdline
Use cmdline as kernel command line
-initrd file
Use file as initial ram disk.
Debug/Expert options:
-serial dev
Redirect the virtual serial port to host character device dev. The
default device is "vc" in graphical mode and "stdio" in non graphi-
cal mode.
This option can be used several times to simulate up to 4 serials
ports.
Use "-serial none" to disable all serial ports.
Available character devices are:
"vc"
Virtual console
"pty"
[Linux only] Pseudo TTY (a new PTY is automatically allocated)
"none"
No device is allocated.
"null"
void device
"/dev/XXX"
[Linux only] Use host tty, e.g. /dev/ttyS0. The host serial
port parameters are set according to the emulated ones.
"/dev/parportN"
[Linux only, parallel port only] Use host parallel port N. Cur-
rently only SPP parallel port features can be used.
"file:filename"
Write output to filename. No character can be read.
"stdio"
[Unix only] standard input/output
"pipe:filename"
name pipe filename
"COMn"
[Windows only] Use host serial port n
"udp:[remote_host]:remote_port[@[src_ip]:src_port]"
This implements UDP Net Console. When remote_host or src_ip
are not specified they default to 0.0.0.0. When not using a
specifed 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:"
-serial udp::4555@4556
"netcat options:"
-u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
"telnet options:"
localhost 5555
"tcp:[host]:port[,server][,nowait][,nodelay]"
The TCP Net Console has two modes of operation. It can send
the serial I/O to a location or wait for a connection from a
location. By default the TCP Net Console is sent to host at
the port. If you use the server option QEMU will wait for a
client socket application to connect to the port before contin-
uing, unless the "nowait" option was specified. The "nodelay"
option disables the Nagle buffering algoritm. If host is omit-
ted, 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"
-serial tcp:192.168.0.2:4444
"Example to listen and wait on port 4444 for connection"
-serial tcp::4444,server
"Example to not wait and listen on ip 192.168.0.100 port 4444"
-serial tcp:192.168.0.100:4444,server,nowait
"telnet:host:port[,server][,nowait][,nodelay]"
The telnet protocol is used instead of raw tcp sockets. The
options work the same as if you had specified "-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.
"unix:path[,server][,nowait]"
A unix domain socket is used instead of a tcp socket. The
option works the same as if you had specified "-serial tcp"
except the unix domain socket path is used for connections.
-parallel dev
Redirect the virtual parallel port to host device dev (same devices
as the serial port). On Linux hosts, /dev/parportN can be used to
use hardware devices connected on the corresponding host parallel
port.
This option can be used several times to simulate up to 3 parallel
ports.
Use "-parallel none" to disable all parallel ports.
-monitor dev
Redirect the monitor to host device dev (same devices as the serial
port). The default device is "vc" in graphical mode and "stdio" in
non graphical mode.
-s Wait gdb connection to port 1234.
-p port
Change gdb connection port. port can be either a decimal number to
specify a TCP port, or a host device (same devices as the serial
port).
-S Do not start CPU at startup (you must type ’c’ in the monitor).
-d Output log in /tmp/qemu.log
-hdachs c,h,s,[,t]
Force hard disk 0 physical geometry (1 <= c <= 16383, 1 <= h <= 16,
1 <= s <= 63) and optionally force the BIOS translation mode
(t=none, lba or auto). Usually QEMU can guess all thoses parame-
ters. This option is useful for old MS-DOS disk images.
-L path
Set the directory for the BIOS, VGA BIOS and keymaps.
-std-vga
Simulate a standard VGA card with Bochs VBE extensions (default is
Cirrus Logic GD5446 PCI VGA). If your guest OS supports the VESA
2.0 VBE extensions (e.g. Windows XP) and if you want to use high
resolution modes (>= 1280x1024x16) then you should use this option.
-no-acpi
Disable ACPI (Advanced Configuration and Power Interface) support.
Use it if your guest OS complains about ACPI problems (PC target
machine only).
-no-reboot
Exit instead of rebooting.
-loadvm file
Start right away with a saved state ("loadvm" in monitor)
-semihosting
Enable "Angel" semihosting interface (ARM target machines only).
Note that this allows guest direct access to the host filesystem,
so should only be used with trusted guest OS.
During the graphical emulation, you can use the following keys:
Ctrl-Alt-f
Toggle full screen
Ctrl-Alt-n
Switch to virtual console ’n’. Standard console mappings are:
1 Target system display
2 Monitor
3 Serial port
Ctrl-Alt
Toggle mouse and keyboard grab.
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:
Ctrl-a h
Print this help
Ctrl-a x
Exit emulator
Ctrl-a s
Save disk data back to file (if -snapshot)
Ctrl-a b
Send break (magic sysrq in Linux)
Ctrl-a c
Switch between console and monitor
Ctrl-a Ctrl-a
Send Ctrl-a
The following options are specific to the PowerPC emulation:
-g WxH[xDEPTH]
Set the initial VGA graphic mode. The default is 800x600x15.
The following options are specific to the Sparc emulation:
-g WxH
Set the initial TCX graphic mode. The default is 1024x768.
SEE ALSO
The HTML documentation of QEMU for more precise information and Linux
user mode emulator invocation.
AUTHOR
Fabrice Bellard
2007-09-12 QEMU(1)
