Archipelago » qemu

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General options:

@table @option

@item -h

Display help and exit

@item -M @var{machine}

Select the emulated @var{machine} (@code{-M ?} for list)

@item -cpu @var{model}

Select CPU model (-cpu ? for list and additional feature selection)

@item -smp @var{n}

Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255

CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs

to 4.

@item -fda @var{file}

@item -fdb @var{file}

Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}). You can

use the host floppy by using @file{/dev/fd0} as filename (@pxref{host_drives}).

@item -hda @var{file}

@item -hdb @var{file}

@item -hdc @var{file}

@item -hdd @var{file}

Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).

@item -cdrom @var{file}

Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and

@option{-cdrom} at the same time). You can use the host CD-ROM by

using @file{/dev/cdrom} as filename (@pxref{host_drives}).

@item -drive @var{option}[,@var{option}[,@var{option}[,...]]]

Define a new drive. Valid options are:

@table @code

@item file=@var{file}

This option defines which disk image (@pxref{disk_images}) to use with

this drive. If the filename contains comma, you must double it

(for instance, "file=my,,file" to use file "my,file").

@item if=@var{interface}

This option defines on which type on interface the drive is connected.

Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio.

@item bus=@var{bus},unit=@var{unit}

These options define where is connected the drive by defining the bus number and

the unit id.

@item index=@var{index}

This option defines where is connected the drive by using an index in the list

of available connectors of a given interface type.

@item media=@var{media}

This option defines the type of the media: disk or cdrom.

@item cyls=@var{c},heads=@var{h},secs=@var{s}[,trans=@var{t}]

These options have the same definition as they have in @option{-hdachs}.

@item snapshot=@var{snapshot}

@var{snapshot} is "on" or "off" and allows to enable snapshot for given drive (see @option{-snapshot}).

@item cache=@var{cache}

@var{cache} is "none", "writeback", or "writethrough" and controls how the host cache is used to access block data.

@item format=@var{format}

Specify which disk @var{format} will be used rather than detecting

the format.  Can be used to specifiy format=raw to avoid interpreting

an untrusted format header.

@item serial=@var{serial}

This option specifies the serial number to assign to the device.

@end table

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 @option{-snapshot} option, writeback caching is

used by default.

The host page can be avoided entirely with @option{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 @option{cache=writethrough}, most notably,

qcow2.  If performance is more important than correctness,

@option{cache=writeback} should be used with qcow2.  By default, if no explicit

caching is specified for a qcow2 disk image, @option{cache=writeback} will be

used.  For all other disk types, @option{cache=writethrough} is the default.

Instead of @option{-cdrom} you can use:

@example

qemu -drive file=file,index=2,media=cdrom

@end example

Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can

use:

@example

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

@end example

You can connect a CDROM to the slave of ide0:

@example

qemu -drive file=file,if=ide,index=1,media=cdrom

@end example

If you don't specify the "file=" argument, you define an empty drive:

@example

qemu -drive if=ide,index=1,media=cdrom

@end example

You can connect a SCSI disk with unit ID 6 on the bus #0:

@example

qemu -drive file=file,if=scsi,bus=0,unit=6

@end example

Instead of @option{-fda}, @option{-fdb}, you can use:

@example

qemu -drive file=file,index=0,if=floppy

qemu -drive file=file,index=1,if=floppy

@end example

By default, @var{interface} is "ide" and @var{index} is automatically

incremented:

@example

qemu -drive file=a -drive file=b"

@end example

is interpreted like:

@example

qemu -hda a -hdb b

@end example

@item -mtdblock file

Use 'file' as on-board Flash memory image.

@item -sd file

Use 'file' as SecureDigital card image.

@item -pflash file

Use 'file' as a parallel flash image.

@item -boot [a|c|d|n]

Boot on floppy (a), hard disk (c), CD-ROM (d), or Etherboot (n). Hard disk boot

is the default.

@item -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 @key{C-a s} (@pxref{disk_images}).

@item -m @var{megs}

Set virtual RAM size to @var{megs} megabytes. Default is 128 MiB.  Optionally,

a suffix of ``M'' or ``G'' can be used to signify a value in megabytes or

gigabytes respectively.

@item -k @var{language}

Use keyboard layout @var{language} (for example @code{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:

@example

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

@end example

The default is @code{en-us}.

@item -audio-help

Will show the audio subsystem help: list of drivers, tunable

parameters.

@item -soundhw @var{card1}[,@var{card2},...] or -soundhw all

Enable audio and selected sound hardware. Use ? to print all

available sound hardware.

@example

qemu -soundhw sb16,adlib disk.img

qemu -soundhw es1370 disk.img

qemu -soundhw ac97 disk.img

qemu -soundhw all disk.img

qemu -soundhw ?

@end example

Note that Linux's i810_audio OSS kernel (for AC97) module might

require manually specifying clocking.

@example

modprobe i810_audio clocking=48000

@end example

@end table

USB options:

@table @option

@item -usb

Enable the USB driver (will be the default soon)

@item -usbdevice @var{devname}

Add the USB device @var{devname}. @xref{usb_devices}.

@table @code

@item mouse

Virtual Mouse. This will override the PS/2 mouse emulation when activated.

@item tablet

Pointer device that uses absolute coordinates (like a touchscreen). This

means qemu is able to report the mouse position without having to grab the

mouse. Also overrides the PS/2 mouse emulation when activated.

@item disk:[format=@var{format}]:file

Mass storage device based on file. The optional @var{format} argument

will be used rather than detecting the format. Can be used to specifiy

format=raw to avoid interpreting an untrusted format header.

@item host:bus.addr

Pass through the host device identified by bus.addr (Linux only).

@item host:vendor_id:product_id

Pass through the host device identified by vendor_id:product_id (Linux only).

@item serial:[vendorid=@var{vendor_id}][,productid=@var{product_id}]:@var{dev}

Serial converter to host character device @var{dev}, see @code{-serial} for the

available devices.

@item braille

Braille device.  This will use BrlAPI to display the braille output on a real

or fake device.

@item net:options

Network adapter that supports CDC ethernet and RNDIS protocols.

@end table

@item -name @var{name}

Sets the @var{name} of the guest.

This name will be displayed in the SDL window caption.

The @var{name} will also be used for the VNC server.

@item -uuid @var{uuid}

Set system UUID.

@end table

Display options:

@table @option

@item -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.

@item -curses

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.

@item -no-frame

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.

@item -alt-grab

Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt).

@item -no-quit

Disable SDL window close capability.

@item -sdl

Enable SDL.

@item -portrait

Rotate graphical output 90 deg left (only PXA LCD).

@item -vga @var{type}

Select type of VGA card to emulate. Valid values for @var{type} are

@table @code

@item cirrus

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.

(This one is the default)

@item std

Standard VGA card with Bochs VBE extensions.  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.

@item vmware

VMWare SVGA-II compatible adapter. Use it if you have sufficiently

recent XFree86/XOrg server or Windows guest with a driver for this

card.

@item none

Disable VGA card.

@end table

@item -full-screen

Start in full screen.

@item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]

Normally, QEMU uses SDL to display the VGA output.  With this option,

you can have QEMU listen on VNC display @var{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 @option{-usbdevice

tablet}). When using the VNC display, you must use the @option{-k}

parameter to set the keyboard layout if you are not using en-us. Valid

syntax for the @var{display} is

@table @code

@item @var{host}:@var{d}

TCP connections will only be allowed from @var{host} on display @var{d}.

By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can

be omitted in which case the server will accept connections from any host.

@item @code{unix}:@var{path}

Connections will be allowed over UNIX domain sockets where @var{path} is the

location of a unix socket to listen for connections on.

@item none

VNC is initialized but not started. The monitor @code{change} command

can be used to later start the VNC server.

@end table

Following the @var{display} value there may be one or more @var{option} flags

separated by commas. Valid options are

@table @code

@item reverse

Connect to a listening VNC client via a ``reverse'' connection. The

client is specified by the @var{display}. For reverse network

connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument

is a TCP port number, not a display number.

@item password

Require that password based authentication is used for client connections.

The password must be set separately using the @code{change} command in the

@ref{pcsys_monitor}

@item tls

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

@var{x509} or @var{x509verify} options.

@item x509=@var{/path/to/certificate/dir}

Valid if @option{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 @ref{vnc_security} section for details on generating certificates.

@item x509verify=@var{/path/to/certificate/dir}

Valid if @option{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 @ref{vnc_security} section for details on generating

certificates.

@item sasl

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 @ref{vnc_security} section for details on using

SASL authentication.

@item acl

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

@code{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 @code{bob} or @code{bob@@EXAMPLE.COM}.

When the @option{acl} flag is set, the initial access list will be

empty, with a @code{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 @code{acl} monitor command.

@end table

@end table

Network options:

@table @option

@item -net nic[,vlan=@var{n}][,macaddr=@var{addr}][,model=@var{type}][,name=@var{name}]

Create a new Network Interface Card and connect it to VLAN @var{n} (@var{n}

= 0 is the default). The NIC is an ne2k_pci by default on the PC

target. Optionally, the MAC address can be changed to @var{addr}

and a @var{name} can be assigned for use in monitor commands. If no

@option{-net} option is specified, a single NIC is created.

Qemu can emulate several different models of network card.

Valid values for @var{type} are

@code{i82551}, @code{i82557b}, @code{i82559er},

@code{ne2k_pci}, @code{ne2k_isa}, @code{pcnet}, @code{rtl8139},

@code{e1000}, @code{smc91c111}, @code{lance} and @code{mcf_fec}.

Not all devices are supported on all targets.  Use -net nic,model=?

for a list of available devices for your target.

@item -net user[,vlan=@var{n}][,hostname=@var{name}][,name=@var{name}]

Use the user mode network stack which requires no administrator

privilege to run.  @option{hostname=name} can be used to specify the client

hostname reported by the builtin DHCP server.

@item -net channel,@var{port}:@var{dev}

Forward @option{user} TCP connection to port @var{port} to character device @var{dev}

@item -net tap[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}]

Connect the host TAP network interface @var{name} to VLAN @var{n}, use

the network script @var{file} to configure it and the network script 

@var{dfile} to deconfigure it. If @var{name} is not provided, the OS 

automatically provides one. @option{fd}=@var{h} can be used to specify

the handle of an already opened host TAP interface. The default network 

configure script is @file{/etc/qemu-ifup} and the default network 

deconfigure script is @file{/etc/qemu-ifdown}. Use @option{script=no} 

or @option{downscript=no} to disable script execution. Example:

@example

qemu linux.img -net nic -net tap

@end example

More complicated example (two NICs, each one connected to a TAP device)

@example

qemu linux.img -net nic,vlan=0 -net tap,vlan=0,ifname=tap0 \

               -net nic,vlan=1 -net tap,vlan=1,ifname=tap1

@end example

@item -net socket[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]

Connect the VLAN @var{n} to a remote VLAN in another QEMU virtual

machine using a TCP socket connection. If @option{listen} is

specified, QEMU waits for incoming connections on @var{port}

(@var{host} is optional). @option{connect} is used to connect to

another QEMU instance using the @option{listen} option. @option{fd}=@var{h}

specifies an already opened TCP socket.

Example:

@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

@end example

@item -net socket[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,mcast=@var{maddr}:@var{port}]

Create a VLAN @var{n} shared with another QEMU virtual

machines using a UDP multicast socket, effectively making a bus for

every QEMU with same multicast address @var{maddr} and @var{port}.

NOTES:

@enumerate

@item

Several QEMU can be running on different hosts and share same bus (assuming

correct multicast setup for these hosts).

@item

mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see

@url{http://user-mode-linux.sf.net}.

@item

Use @option{fd=h} to specify an already opened UDP multicast socket.

@end enumerate

Example:

@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

@end example

Example (User Mode Linux compat.):

@example

# 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

@end example

@item -net vde[,vlan=@var{n}][,name=@var{name}][,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]

Connect VLAN @var{n} to PORT @var{n} of a vde switch running on host and

listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname}

and MODE @var{octalmode} to change default ownership and permissions for

communication port. This option is available only if QEMU has been compiled

with vde support enabled.

Example:

@example

# launch vde switch

vde_switch -F -sock /tmp/myswitch

# launch QEMU instance

qemu linux.img -net nic -net vde,sock=/tmp/myswitch

@end example

@item -net none

Indicate that no network devices should be configured. It is used to

override the default configuration (@option{-net nic -net user}) which

is activated if no @option{-net} options are provided.

@item -tftp @var{dir}

When using the user mode network stack, activate a built-in TFTP

server. The files in @var{dir} will be exposed as the root of a TFTP server.

The TFTP client on the guest must be configured in binary mode (use the command

@code{bin} of the Unix TFTP client). The host IP address on the guest is as

usual 10.0.2.2.

@item -bootp @var{file}

When using the user mode network stack, broadcast @var{file} as the BOOTP

filename.  In conjunction with @option{-tftp}, this can be used to network boot

a guest from a local directory.

Example (using pxelinux):

@example

qemu -hda linux.img -boot n -tftp /path/to/tftp/files -bootp /pxelinux.0

@end example

@item -smb @var{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 @file{@var{dir}}

transparently.

In the guest Windows OS, the line:

@example

10.0.2.4 smbserver

@end example

must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)

or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).

Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.

Note that a SAMBA server must be installed on the host OS in

@file{/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.

@item -redir [tcp|udp]:@var{host-port}:[@var{guest-host}]:@var{guest-port}

When using the user mode network stack, redirect incoming TCP or UDP

connections to the host port @var{host-port} to the guest

@var{guest-host} on guest port @var{guest-port}. If @var{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:

@example

# on the host

qemu -redir tcp:6001::6000 [...]

# this host xterm should open in the guest X11 server

xterm -display :1

@end example

To redirect telnet connections from host port 5555 to telnet port on

the guest, use the following:

@example

# on the host

qemu -redir tcp:5555::23 [...]

telnet localhost 5555

@end example

Then when you use on the host @code{telnet localhost 5555}, you

connect to the guest telnet server.

@end table

Bluetooth(R) options:

@table @option

@item -bt hci[...]

Defines the function of the corresponding Bluetooth HCI.  -bt options

are matched with the HCIs present in the chosen machine type.  For

example when emulating a machine with only one HCI built into it, only

the first @code{-bt hci[...]} option is valid and defines the HCI's

logic.  The Transport Layer is decided by the machine type.  Currently

the machines @code{n800} and @code{n810} have one HCI and all other

machines have none.

@anchor{bt-hcis}

The following three types are recognized:

@table @code

@item -bt hci,null

(default) The corresponding Bluetooth HCI assumes no internal logic

and will not respond to any HCI commands or emit events.

@item -bt hci,host[:@var{id}]

(@code{bluez} only) The corresponding HCI passes commands / events

to / from the physical HCI identified by the name @var{id} (default:

@code{hci0}) on the computer running QEMU.  Only available on @code{bluez}

capable systems like Linux.

@item -bt hci[,vlan=@var{n}]

Add a virtual, standard HCI that will participate in the Bluetooth

scatternet @var{n} (default @code{0}).  Similarly to @option{-net}

VLANs, devices inside a bluetooth network @var{n} can only communicate

with other devices in the same network (scatternet).

@end table

@item -bt vhci[,vlan=@var{n}]

(Linux-host only) Create a HCI in scatternet @var{n} (default 0) attached

to the host bluetooth stack instead of to the emulated target.  This

allows the host and target machines to participate in a common scatternet

and communicate.  Requires the Linux @code{vhci} driver installed.  Can

be used as following:

@example

qemu [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5

@end example

@item -bt device:@var{dev}[,vlan=@var{n}]

Emulate a bluetooth device @var{dev} and place it in network @var{n}

(default @code{0}).  QEMU can only emulate one type of bluetooth devices

currently:

@table @code

@item keyboard

Virtual wireless keyboard implementing the HIDP bluetooth profile.

@end table

@end table

i386 target only:

@table @option

@item -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).

@item -rtc-td-hack

Use it if you experience time drift problem in Windows with 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.

@item -no-fd-bootchk

Disable boot signature checking for floppy disks in Bochs BIOS. It may

be needed to boot from old floppy disks.

@item -no-acpi

Disable ACPI (Advanced Configuration and Power Interface) support. Use

it if your guest OS complains about ACPI problems (PC target machine

only).

@item -no-hpet

Disable HPET support.

@item -acpitable [sig=@var{str}][,rev=@var{n}][,oem_id=@var{str}][,oem_table_id=@var{str}][,oem_rev=@var{n}] [,asl_compiler_id=@var{str}][,asl_compiler_rev=@var{n}][,data=@var{file1}[:@var{file2}]...]

Add ACPI table with specified header fields and context from specified files.

@end table

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.

@table @option

@item -kernel @var{bzImage}

Use @var{bzImage} as kernel image.

@item -append @var{cmdline}

Use @var{cmdline} as kernel command line

@item -initrd @var{file}

Use @var{file} as initial ram disk.

@end table

Debug/Expert options:

@table @option

@item -serial @var{dev}

Redirect the virtual serial port to host character device

@var{dev}. The default device is @code{vc} in graphical mode and

@code{stdio} in non graphical mode.

This option can be used several times to simulate up to 4 serial

ports.

Use @code{-serial none} to disable all serial ports.

Available character devices are:

@table @code

@item vc[:WxH]

Virtual console. Optionally, a width and height can be given in pixel with

@example

vc:800x600

@end example

It is also possible to specify width or height in characters:

@example

vc:80Cx24C

@end example

@item pty

[Linux only] Pseudo TTY (a new PTY is automatically allocated)

@item none

No device is allocated.

@item null

void device

@item /dev/XXX

[Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port

parameters are set according to the emulated ones.

@item /dev/parport@var{N}

[Linux only, parallel port only] Use host parallel port

@var{N}. Currently SPP and EPP parallel port features can be used.

@item file:@var{filename}

Write output to @var{filename}. No character can be read.

@item stdio

[Unix only] standard input/output

@item pipe:@var{filename}

name pipe @var{filename}

@item COM@var{n}

[Windows only] Use host serial port @var{n}

@item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]

This implements UDP Net Console.

When @var{remote_host} or @var{src_ip} are not specified

they default to @code{0.0.0.0}.

When not using a specified @var{src_port} a random port is automatically chosen.

@item msmouse

Three button serial mouse. Configure the guest to use Microsoft protocol.

If you just want a simple readonly console you can use @code{netcat} or

@code{nc}, by starting qemu with: @code{-serial udp::4555} and nc as:

@code{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 @code{-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.

@table @code

@item Qemu Options:

-serial udp::4555@@:4556

@item netcat options:

-u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T

@item telnet options:

localhost 5555

@end table

@item tcp:[@var{host}]:@var{port}[,@var{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 @var{host} at the @var{port}.  If you use

the @var{server} option QEMU will wait for a client socket application

to connect to the port before continuing, unless the @code{nowait}

option was specified.  The @code{nodelay} option disables the Nagle buffering

algorithm.  If @var{host} is omitted, 0.0.0.0 is assumed. Only

one TCP connection at a time is accepted. You can use @code{telnet} to

connect to the corresponding character device.

@table @code

@item Example to send tcp console to 192.168.0.2 port 4444

-serial tcp:192.168.0.2:4444

@item Example to listen and wait on port 4444 for connection

-serial tcp::4444,server

@item Example to not wait and listen on ip 192.168.0.100 port 4444

-serial tcp:192.168.0.100:4444,server,nowait

@end table

@item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]

The telnet protocol is used instead of raw tcp sockets.  The options

work the same as if you had specified @code{-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.

@item unix:@var{path}[,server][,nowait]

A unix domain socket is used instead of a tcp socket.  The option works the

same as if you had specified @code{-serial tcp} except the unix domain socket

@var{path} is used for connections.

@item mon:@var{dev_string}

This is a special option to allow the monitor to be multiplexed onto

another serial port.  The monitor is accessed with key sequence of

@key{Control-a} and then pressing @key{c}. See monitor access

@ref{pcsys_keys} in the -nographic section for more keys.

@var{dev_string} should be any one of the serial devices specified

above.  An example to multiplex the monitor onto a telnet server

listening on port 4444 would be:

@table @code

@item -serial mon:telnet::4444,server,nowait

@end table

@item braille

Braille device.  This will use BrlAPI to display the braille output on a real

or fake device.

@end table

@item -parallel @var{dev}

Redirect the virtual parallel port to host device @var{dev} (same

devices as the serial port). On Linux hosts, @file{/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 @code{-parallel none} to disable all parallel ports.

@item -monitor @var{dev}

Redirect the monitor to host device @var{dev} (same devices as the

serial port).

The default device is @code{vc} in graphical mode and @code{stdio} in

non graphical mode.

@item -pidfile @var{file}

Store the QEMU process PID in @var{file}. It is useful if you launch QEMU

from a script.

@item -S

Do not start CPU at startup (you must type 'c' in the monitor).

@item -s

Wait gdb connection to port 1234 (@pxref{gdb_usage}).

@item -p @var{port}

Change gdb connection port.  @var{port} can be either a decimal number

to specify a TCP port, or a host device (same devices as the serial port).

@item -d

Output log in /tmp/qemu.log

@item -hdachs @var{c},@var{h},@var{s},[,@var{t}]

Force hard disk 0 physical geometry (1 <= @var{c} <= 16383, 1 <=

@var{h} <= 16, 1 <= @var{s} <= 63) and optionally force the BIOS

translation mode (@var{t}=none, lba or auto). Usually QEMU can guess

all those parameters. This option is useful for old MS-DOS disk

images.

@item -L  @var{path}

Set the directory for the BIOS, VGA BIOS and keymaps.

@item -bios @var{file}

Set the filename for the BIOS.

@item -kernel-kqemu

Enable KQEMU full virtualization (default is user mode only).

@item -no-kqemu

Disable KQEMU kernel module usage. KQEMU options are only available if

KQEMU support is enabled when compiling.

@item -enable-kvm

Enable KVM full virtualization support. This option is only available

if KVM support is enabled when compiling.

@item -no-reboot

Exit instead of rebooting.

@item -no-shutdown

Don't exit QEMU on guest shutdown, but instead only stop the emulation.

This allows for instance switching to monitor to commit changes to the

disk image.

@item -loadvm @var{file}

Start right away with a saved state (@code{loadvm} in monitor)

@item -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.

@item -option-rom @var{file}

Load the contents of @var{file} as an option ROM.

This option is useful to load things like EtherBoot.

@item -clock @var{method}

Force the use of the given methods for timer alarm. To see what timers

are available use -clock ?.

@item -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.

@item -startdate @var{date}

Set the initial date of the real time clock. Valid formats for

@var{date} are: @code{now} or @code{2006-06-17T16:01:21} or

@code{2006-06-17}. The default value is @code{now}.

@item -icount [N|auto]

Enable virtual instruction counter.  The virtual cpu will execute one

instruction every 2^N ns of virtual time.  If @code{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.

@item -echr numeric_ascii_value

Change the escape character used for switching to the monitor when using

monitor and serial sharing.  The default is @code{0x01} when using the

@code{-nographic} option.  @code{0x01} is equal to pressing

@code{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.

@table @code

@item -echr 0x14

@item -echr 20

@end table

@item -chroot dir

Immediately before starting guest execution, chroot to the specified

directory.  Especially useful in combination with -runas.

@item -runas user

Immediately before starting guest execution, drop root privileges, switching

to the specified user.

@end table