Man Linux: Main Page and Category List


       qemu-doc - QEMU Emulator User Documentation


       usage: qemu [options] [disk_image]


       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

       -   PCI and ISA network adapters

       -   Serial ports

       -   Creative SoundBlaster 16 sound card

       -   ENSONIQ AudioPCI ES1370 sound card

       -   Intel 82801AA AC97 Audio compatible sound card

       -   Adlib(OPL2) - Yamaha YM3812 compatible chip

       -   Gravis Ultrasound GF1 sound card

       -   CS4231A compatible sound card

       -   PCI UHCI USB controller and a virtual USB hub.

       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 <>)
       by Tibor "TS" SchA~Xtz.

       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


               qemu dos.img -device gus,irq=5

       Or some other unclaimed IRQ.

       CS4231A is the chip used in Windows Sound System and GUSMAX products


       disk_image is a raw hard disk image for IDE hard disk 0. Some targets
       do not need a disk image.

       Standard options:

       -h  Display help and exit

           Display version information and exit

       -M machine
           Select the emulated machine ("-M ?" for list)

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

           Simulate an SMP system with n CPUs. On the PC target, up to 255
           CPUs are supported. On Sparc32 target, Linux limits the number of
           usable CPUs to 4.  For the PC target, the number of cores per
           socket, the number of threads per cores and the total number of
           sockets can be specified. Missing values will be computed. If any
           on the three values is given, the total number of CPUs n can be
           omitted. maxcpus specifies the maximum number of hotpluggable CPUs.

       -numa opts
           Simulate a multi node NUMA system. If mem and cpus are omitted,
           resources are split equally.

       -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 -cdrom at the
           same time). You can use the host CD-ROM by using /dev/cdrom as

       -drive option[,option[,option[,...]]]
           Define a new drive. Valid options are:

               This option defines which disk image to use with this drive. If
               the filename contains comma, you must double it (for instance,
               "file=my,,file" to use file "my,file").

               This option defines on which type on interface the drive is
               connected.  Available types are: ide, scsi, sd, mtd, floppy,
               pflash, virtio.

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

               This option defines where is connected the drive by using an
               index in the list of available connectors of a given interface

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

               These options have the same definition as they have in -hdachs.

               snapshot is "on" or "off" and allows to enable snapshot for
               given drive (see -snapshot).

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

               aio is "threads", or "native" and selects between pthread based
               disk I/O and native Linux AIO.

               Specify which disk format will be used rather than detecting
               the format.  Can be used to specifiy format=raw to avoid
               interpreting an untrusted format header.

               This option specifies the serial number to assign to the

               Specify the controller's PCI address (if=virtio only).

           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

                   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

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

           is interpreted like:

                   qemu -hda a -hdb b

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

       -sd file
           Use file as SecureDigital card image.

       -pflash file
           Use file as a parallel flash image.

       -boot [order=drives][,once=drives][,menu=on|off]
           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.

           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.

       -m megs
           Set virtual RAM size to 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.

       -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".

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

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

       USB options:

           Enable the USB driver (will be the default soon)

       -usbdevice devname
           Add the USB device devname.

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

               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.

               Mass storage device based on file. The optional format argument
               will be used rather than detecting the format. Can be used to
               specifiy "format=raw" to avoid interpreting an untrusted format

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

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

               Serial converter to host character device dev, see "-serial"
               for the available devices.

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

               Network adapter that supports CDC ethernet and RNDIS protocols.

       -device driver[,option[,...]]
           Add device driver. Depending on the device type, option (typically
           key=value) may be useful.

       -name name
           Sets the name of the guest.  This name will be displayed in the SDL
           window caption.  The name will also be used for the VNC server.
           Also optionally set the top visible process name in Linux.

       -uuid uuid
           Set system UUID.

       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).

       -vga type
           Select type of VGA card to emulate. Valid values for type are

               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)

           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.

               VMWare SVGA-II compatible adapter. Use it if you have
               sufficiently recent XFree86/XOrg server or Windows guest with a
               driver for this card.

               Disable VGA card.

           Start in full screen.

       -vnc display[,option[,option[,...]]]
           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 pcsys_monitor

           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 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 vnc_security section for details on generating

               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
               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 vnc_security
               section for details on using SASL authentication.

           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 "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

       i386 target only:

           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).

           Disable boot signature checking for floppy disks in Bochs BIOS. It
           may be needed to boot from old floppy disks.

           Disable ACPI (Advanced Configuration and Power Interface) support.
           Use it if your guest OS complains about ACPI problems (PC target
           machine only).

           Disable HPET support.

       -balloon none
           Disable balloon device.

       -balloon virtio[,addr=addr]
           Enable virtio balloon device (default), optionally with PCI address

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

       -smbios file=binary
           Load SMBIOS entry from binary file.

       -smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]
           Specify SMBIOS type 0 fields

           Specify SMBIOS type 1 fields

       Network options:

           Create a new Network Interface Card and connect it to VLAN n (n = 0
           is the default). The NIC is an e1000 by default on the PC target.
           Optionally, the MAC address can be changed to mac, the device
           address set to addr (PCI cards only), and a name can be assigned
           for use in monitor commands.  Optionally, for PCI cards, you can
           specify the number v of MSI-X vectors that the card should have;
           this option currently only affects virtio cards; set v = 0 to
           disable MSI-X. 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 "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.

       -net user[,option][,option][,...]
           Use the user mode network stack which requires no administrator
           privilege to run. Valid options are:

               Connect user mode stack to VLAN n (n = 0 is the default).

               Assign symbolic name for use in monitor commands.

               Set IP network address the guest will see. Optionally specify
               the netmask, either in the form a.b.c.d or as number of valid
               top-most bits. Default is

               Specify the guest-visible address of the host. Default is the
               2nd IP in the guest network, i.e. x.x.x.2.

               If this options is enabled, the guest will be isolated, i.e. it
               will not be able to contact the host and no guest IP packets
               will be routed over the host to the outside. This option does
               not affect explicitly set forwarding rule.

               Specifies the client hostname reported by the builtin DHCP

               Specify the first of the 16 IPs the built-in DHCP server can
               assign. Default is the 16th to 31st IP in the guest network,
               i.e. x.x.x.16 to x.x.x.31.

               Specify the guest-visible address of the virtual nameserver.
               The address must be different from the host address. Default is
               the 3rd IP in the guest network, i.e. x.x.x.3.

               When using the user mode network stack, activate a built-in
               TFTP server. The files in 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 "bin" of the Unix TFTP client).

               When using the user mode network stack, broadcast file as the
               BOOTP filename. In conjunction with tftp, this can be used to
               network boot a guest from a local directory.

               Example (using pxelinux):

                       qemu -hda linux.img -boot n -net user,tftp=/path/to/tftp/files,bootfile=/pxelinux.0

               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. The IP address of the SMB server can be set to
               addr. By default the 4th IP in the guest network is used, i.e.

               In the guest Windows OS, the line:


               must be added in the file C:\WINDOWS\LMHOSTS (for windows
               9x/Me) or C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS (Windows

               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.

               Redirect incoming TCP or UDP connections to the host port
               hostport to the guest IP address guestaddr on guest port
               guestport. If guestaddr is not specified, its value is x.x.x.15
               (default first address given by the built-in DHCP server). By
               specifying hostaddr, the rule can be bound to a specific host
               interface. If no connection type is set, TCP is used. This
               option can be given multiple times.

               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: [...]
                       # 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.

               Forward guest TCP connections to the IP address server on port
               port to the character device dev. This option can be given
               multiple times.

           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

           Connect the host TAP network interface name to VLAN n, use the
           network script file to configure it and the network script dfile to
           deconfigure it. 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. The default network configure script is
           /etc/qemu-ifup and the default network deconfigure script is
           /etc/qemu-ifdown. Use script=no or downscript=no to disable script
           execution. Example:

                   qemu linux.img -net nic -net tap

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

                   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.


                   # 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=

       -net socket[,vlan=n][,name=name][,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.


                   # launch one QEMU instance
                   qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \
                   -net socket,mcast=
                   # launch another QEMU instance on same "bus"
                   qemu linux.img -net nic,macaddr=52:54:00:12:34:57 \
                   -net socket,mcast=
                   # launch yet another QEMU instance on same "bus"
                   qemu linux.img -net nic,macaddr=52:54:00:12:34:58 \
                   -net socket,mcast=

           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=
                   # launch UML
                   /path/to/linux ubd0=/path/to/root_fs eth0=mcast

           Connect VLAN n to PORT n of a vde switch running on host and
           listening for incoming connections on socketpath. Use GROUP
           groupname and MODE octalmode to change default ownership and
           permissions for communication port. This option is available only
           if QEMU has been compiled with vde support enabled.


                   # launch vde switch
                   vde_switch -F -sock /tmp/myswitch
                   # launch QEMU instance
                   qemu linux.img -net nic -net vde,sock=/tmp/myswitch

       -net dump[,vlan=n][,file=file][,len=len]
           Dump network traffic on VLAN n to file file (qemu-vlan0.pcap by
           default).  At most len bytes (64k by default) per packet are
           stored. The file format is libpcap, so it can be analyzed with
           tools such as tcpdump or Wireshark.

       -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.

       Character device options:

       The general form of a character device option is:

       -chardev backend ,id=id [,options]
           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.

       -chardev null ,id=id
           A void device. This device will not emit any data, and will drop
           any data it receives. The null backend does not take any options.

       -chardev socket ,id=id [TCP options or unix options] [,server]
       [,nowait] [,telnet]
           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

           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:

           TCP options: port=host [,host=host] [,to=to] [,ipv4] [,ipv6]
               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

               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.

           unix options: path=path
               path specifies the local path of the unix socket. path is

       -chardev udp ,id=id [,host=host] ,port=port [,localaddr=localaddr]
       [,localport=localport] [,ipv4] [,ipv6]
           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

           localaddr specifies the local address to bind to. If not specified
           it defaults to

           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.

       -chardev msmouse ,id=id
           Forward QEMU's emulated msmouse events to the guest. msmouse does
           not take any options.

       -chardev vc ,id=id [[,width=width] [,height=height]] [[,cols=cols]
           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.

       -chardev file ,id=id ,path=path
           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.

       -chardev pipe ,id=id ,path=path
           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 and
           path.out. Data written to 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

       -chardev console ,id=id
           Send traffic from the guest to QEMU's standard output. console does
           not take any options.

           console is only available on Windows hosts.

       -chardev serial ,id=id ,path=path
           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.

       -chardev pty ,id=id
           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.

       -chardev stdio ,id=id [,signal=on|off]
           Connect to standard input and standard output of the qemu process.

           signal controls if signals are enabled on the terminal, that
           includes exiting QEMU with the key sequence Control-c. This option
           is enabled by default, use signal=off to disable it.

           stdio is not available on Windows hosts.

       -chardev braille ,id=id
           Connect to a local BrlAPI server. braille does not take any

       -chardev tty ,id=id ,path=path
           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.

       -chardev parport ,id=id ,path=path
           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

       Bluetooth(R) options:

       -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 "-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:

           -bt hci,null
               (default) The corresponding Bluetooth HCI assumes no internal
               logic and will not respond to any HCI commands or emit events.

           -bt hci,host[:id]
               ("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.

           -bt hci[,vlan=n]
               Add a virtual, standard HCI that will participate in the
               Bluetooth scatternet n (default 0).  Similarly to -net VLANs,
               devices inside a bluetooth network n can only communicate with
               other devices in the same network (scatternet).

       -bt vhci[,vlan=n]
           (Linux-host only) Create a HCI in scatternet 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 "vhci" driver
           installed.  Can be used as following:

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

       -bt device:dev[,vlan=n]
           Emulate a bluetooth device dev and place it in network n (default
           0).  QEMU can only emulate one type of bluetooth devices currently:

               Virtual wireless keyboard implementing the HIDP bluetooth

       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.

       -kernel bzImage
           Use bzImage as kernel image. The kernel can be either a Linux
           kernel or in multiboot format.

       -append cmdline
           Use cmdline as kernel command line

       -initrd file
           Use file as initial ram disk.

       -initrd "file1 arg=foo,file2"
           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:

       -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 serial

           Use "-serial none" to disable all serial ports.

           Available character devices are:

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


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


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

               No device is allocated.

               void device

               [Linux only] Use host tty, e.g. /dev/ttyS0. The host serial
               port parameters are set according to the emulated ones.

               [Linux only, parallel port only] Use host parallel port N.
               Currently SPP and EPP parallel port features can be used.

               Write output to filename. No character can be read.

               [Unix only] standard input/output

               name pipe filename

               [Windows only] Use host serial port n

               This implements UDP Net Console.  When remote_host or src_ip
               are not specified they default to  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:"
                   -serial udp::4555@4556

               "netcat options:"
                   -u -P 4555 -L -t -p 5555 -I -T

               "telnet options:"
                   localhost 5555

               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 algorithm.  If
               host is omitted, 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 port 4444"
                   -serial tcp:

               "Example to listen and wait on port 4444 for connection"
                   -serial tcp::4444,server

               "Example to not wait and listen on ip port 4444"
                   -serial tcp:,server,nowait

               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.

               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.

               This is a special option to allow the monitor to be multiplexed
               onto another serial port.  The monitor is accessed with key
               sequence of Control-a and then pressing c. See monitor access
               pcsys_keys in the -nographic section for more keys.  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:

               "-serial mon:telnet::4444,server,nowait"
               Braille device.  This will use BrlAPI to display the braille
               output on a real or fake device.

               Three button serial mouse. Configure the guest to use Microsoft

       -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

           This option can be used several times to simulate up to 3 parallel

           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.

       -mon chardev=[name][,mode=readline|control][,default]
           Setup monitor on chardev name.

       -pidfile file
           Store the QEMU process PID in file. It is useful if you launch QEMU
           from a script.

           Run the emulation in single step mode.

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

       -gdb dev
           Wait for gdb connection on device dev. Typical connections will
           likely be TCP-based, but also UDP, pseudo TTY, or even stdio are
           reasonable use case. The latter is allowing to start qemu from
           within gdb and establish the connection via a pipe:

                   (gdb) target remote | exec qemu -gdb stdio ...

       -s  Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port

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

       -L  path
           Set the directory for the BIOS, VGA BIOS and keymaps.

       -bios file
           Set the filename for the BIOS.

           Enable KVM full virtualization support. This option is only
           available if KVM support is enabled when compiling.

           Exit instead of rebooting.

           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.

       -loadvm file
           Start right away with a saved state ("loadvm" in monitor)

           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.

       -option-rom file
           Load the contents of file as an option ROM.  This option is useful
           to load things like EtherBoot.

       -clock method
           Force the use of the given methods for timer alarm. To see what
           timers are available use -clock ?.

       -rtc [base=utc|localtime|date][,clock=host|vm][,driftfix=none|slew]
           Specify base as "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.

       -icount [N|auto]
           Enable virtual instruction counter.  The virtual cpu will execute
           one instruction every 2^N ns of virtual time.  If "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.

       -watchdog model
           Create a virtual hardware watchdog device.  Once enabled (by a
           guest action), the watchdog must be periodically polled by an agent
           inside the guest or else the guest will be restarted.

           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.

       -watchdog-action action
           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.


           "-watchdog i6300esb -watchdog-action pause"
           "-watchdog ib700"
       -echr numeric_ascii_value
           Change the escape character used for switching to the monitor when
           using monitor and serial sharing.  The default is 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"
       -virtioconsole c
           Set virtio console.

           Don't create default devices.

       -chroot dir
           Immediately before starting guest execution, chroot to the
           specified directory.  Especially useful in combination with -runas.

       -runas user
           Immediately before starting guest execution, drop root privileges,
           switching to the specified user.

       -readconfig file
           Read device configuration from file.

       -writeconfig file
           Write device configuration to file.

       During the graphical emulation, you can use the following keys:

           Toggle full screen

           Restore the screen's un-scaled dimensions

           Switch to virtual console 'n'. Standard console mappings are:

           1   Target system display

           2   Monitor

           3   Serial port

           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
       Ctrl-a ?
           Print this help

       Ctrl-a x
           Exit emulator

       Ctrl-a s
           Save disk data back to file (if -snapshot)

       Ctrl-a t
           Toggle console timestamps

       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.

       -prom-env string
           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.

       The following options are specific to the Sparc32 emulation:

       -g WxHx[xDEPTH]
           Set the initial TCX graphic mode. The default is 1024x768x8,
           currently the only other possible mode is 1024x768x24.

       -prom-env string
           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.

       The following options are specific to the Sparc64 emulation:

       -prom-env string
           Set OpenBIOS variables in NVRAM, for example:

                   qemu-system-sparc64 -prom-env 'auto-boot?=false'

       -M [sun4u|sun4v|Niagara]
           Set the emulated machine type. The default is sun4u.


       The HTML documentation of QEMU for more precise information and Linux
       user mode emulator invocation.


       Fabrice Bellard

                                  2010-09-06                           QEMU(1)