qemu(1): QEMU Emulator User Documentation

NAME

qemu-doc - QEMU Emulator User Documentation

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 redirected 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 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 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 parameters.

-soundhw card1,card2,... or -soundhw all

Enable audio and selected sound hardware. Use ? to print all available 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 programs 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 different 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 <>.
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 graphical 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. Currently 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 continuing, unless the "nowait" option was specified. The "nodelay" option disables the Nagle buffering algoritm. 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: -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]