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# 1. Introduction

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## 1.1 Features

QEMU is a FAST! processor emulator using dynamic translation to achieve good emulation speed.

QEMU has two operating modes:

QEMU can run without an host kernel driver and yet gives acceptable performance.

For system emulation, the following hardware targets are supported:

For user emulation, x86, PowerPC, ARM, and Sparc32/64 CPUs are supported.

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# 2. Installation

If you want to compile QEMU yourself, see Compilation from the sources.

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## 2.1 Linux

If a precompiled package is available for your distribution - you just have to install it. Otherwise, see Compilation from the sources.

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## 2.2 Windows

Download the experimental binary installer at http://www.freeoszoo.org/download.php.

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## 2.3 Mac OS X

Download the experimental binary installer at http://www.freeoszoo.org/download.php.

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# 3. QEMU PC System emulator invocation

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## 3.1 Introduction

The QEMU System emulator simulates the following PC peripherals:

QEMU uses the PC BIOS from the Bochs project and the Plex86/Bochs LGPL VGA BIOS.

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## 3.2 Quick Start

Download and uncompress the linux image (``linux.img'`) and type:

    qemu linux.img

Linux should boot and give you a prompt.

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## 3.3 Invocation

    usage: qemu [options] [disk_image]

disk_image is a raw hard disk image for IDE hard disk 0.

General options:

``-fda file'`
``-fdb file'`

  Use file as floppy disk 0/1 image (See section Disk Images). 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 (See section Disk Images).

``-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]'`

  Boot on floppy (a), hard disk (c) or CD-ROM (d). 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` (See section Disk Images).

``-m megs'`

  Set virtual RAM size to megs megabytes. Default is 128 MB.

``-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.

``-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 or with some X11 servers). You don't 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`.

``-enable-audio'`

  The SB16 emulation is disabled by default as it may give problems with Windows. You can enable it manually with this option.

``-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.

``-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).

Network options:

``-n script'`

  Set TUN/TAP network init script [default=/etc/qemu-ifup]. This script is launched to configure the host network interface (usually tun0) corresponding to the virtual NE2000 card.

``-nics n'`

  Simulate n network cards (the default is 1).

``-macaddr addr'`

  Set the mac address of the first interface (the format is aa:bb:cc:dd:ee:ff in hexa). The mac address is incremented for each new network interface.

``-tun-fd fd'`

  Assumes fd talks to a tap/tun host network interface and use it. Read http://bellard.org/qemu/tetrinet.html to have an example of its use.

``-user-net'`

  Use the user mode network stack. This is the default if no tun/tap network init script is found.

``-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 succesfully with smbd version 2.2.7a from the Red Hat 9.

``-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.

``-dummy-net'`

  Use the dummy network stack: no packet will be received by the network cards.

Linux boot specific. When using this 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 device dev. Available devices are:

  `vc`

    Virtual console

  `pty`

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

  `null`

    void device

  `stdio`

    [Unix only] standard input/output

  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.

``-monitor dev'`

  Redirect the monitor to host device dev (same devices as the serial port). The default device is `vc` in graphical mode and `stdio` in non graphical mode.

``-s'`

  Wait gdb connection to port 1234 (See section GDB usage).

``-p port'`

  Change gdb connection port.

``-S'`

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

``-d'`

  Output log in /tmp/qemu.log

``-hdachs c,h,s,[,t]'`

  Force hard disk 0 physical geometry (1 <= c <= 16383, 1 <= h <= 16, 1 <= s <= 63) and optionally force the BIOS translation mode (t=none, lba or auto). Usually QEMU can guess all thoses parameters. This option is useful for old MS-DOS disk images.

``-isa'`

  Simulate an ISA-only system (default is PCI system).

``-std-vga'`

  Simulate a standard VGA card with Bochs VBE extensions (default is Cirrus Logic GD5446 PCI VGA)

``-loadvm file'`

  Start right away with a saved state (`loadvm` in monitor)

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## 3.4 Keys

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

`Ctrl-Alt-f`

  Toggle full screen

`Ctrl-Alt-n`

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

  1

    Target system display

  2

    Monitor

  3

    Serial port

`Ctrl-Alt`

  Toggle mouse and keyboard grab.

In the virtual consoles, you can use `Ctrl-Up`, `Ctrl-Down`, `Ctrl-PageUp` and `Ctrl-PageDown` to move in the back log.

During emulation, if you are using the ``-nographic'` option, use `Ctrl-a h` to get terminal commands:

`Ctrl-a h`

  Print this help

`Ctrl-a x`

  Exit emulatior

`Ctrl-a s`

  Save disk data back to file (if -snapshot)

`Ctrl-a b`

  Send break (magic sysrq in Linux)

`Ctrl-a c`

  Switch between console and monitor

`Ctrl-a Ctrl-a`

  Send Ctrl-a

@end ignore

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## 3.5 QEMU Monitor

The QEMU monitor is used to give complex commands to the QEMU emulator. You can use it to:

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### 3.5.1 Commands

The following commands are available:

``help or ? [cmd]'`

  Show the help for all commands or just for command cmd.

``commit'`

  Commit changes to the disk images (if -snapshot is used)

``info subcommand'`

  show various information about the system state

  ``info network'`

    show the network state

  ``info block'`

    show the block devices

  ``info registers'`

    show the cpu registers

  ``info history'`

    show the command line history

``q or quit'`

  Quit the emulator.

``eject [-f] device'`

  Eject a removable media (use -f to force it).

``change device filename'`

  Change a removable media.

``screendump filename'`

  Save screen into PPM image filename.

``log item1[,...]'`

  Activate logging of the specified items to ``/tmp/qemu.log'`.

``savevm filename'`

  Save the whole virtual machine state to filename.

``loadvm filename'`

  Restore the whole virtual machine state from filename.

``stop'`

  Stop emulation.

``c or cont'`

  Resume emulation.

``gdbserver [port]'`

  Start gdbserver session (default port=1234)

``x/fmt addr'`

  Virtual memory dump starting at addr.

``xp /fmt addr'`

  Physical memory dump starting at addr.

  fmt is a format which tells the command how to format the data. Its syntax is: ``/{count}{format}{size}'`

  count

    is the number of items to be dumped.

  format

    can be x (hexa), d (signed decimal), u (unsigned decimal), o (octal), c (char) or i (asm instruction).

  size

    can be b (8 bits), h (16 bits), w (32 bits) or g (64 bits). On x86, `h` or `w` can be specified with the `i` format to respectively select 16 or 32 bit code instruction size.

  Examples:

``p or print/fmt expr'`

  Print expression value. Only the format part of fmt is used.

``sendkey keys'`

  Send keys to the emulator. Use `-` to press several keys simultaneously. Example:

      sendkey ctrl-alt-f1

  This command is useful to send keys that your graphical user interface intercepts at low level, such as `ctrl-alt-f1` in X Window.

``system_reset'`

  Reset the system.

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### 3.5.2 Integer expressions

The monitor understands integers expressions for every integer argument. You can use register names to get the value of specifics CPU registers by prefixing them with $.

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## 3.6 Disk Images

Since version 0.6.1, QEMU supports many disk image formats, including growable disk images (their size increase as non empty sectors are written), compressed and encrypted disk images.

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### 3.6.1 Quick start for disk image creation

You can create a disk image with the command:

    qemu-img create myimage.img mysize

where myimage.img is the disk image filename and mysize is its size in kilobytes. You can add an `M` suffix to give the size in megabytes and a `G` suffix for gigabytes.

See section `qemu-img` Invocation for more information.

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### 3.6.2 Snapshot mode

If you use the option ``-snapshot'`, all disk images are considered as read only. When sectors in written, they are written in a temporary file created in ``/tmp'`. You can however force the write back to the raw disk images by using the `commit` monitor command (or `C-a s` in the serial console).

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### 3.6.3 `qemu-img` Invocation

    usage: qemu-img command [command options]

The following commands are supported:

``create [-e] [-b base_image] [-f fmt] filename [size]'`
``commit [-f fmt] filename'`
``convert [-c] [-e] [-f fmt] filename [-O output_fmt] output_filename'`
``info [-f fmt] filename'`

Command parameters:

filename

  is a disk image filename

base_image

  is the read-only disk image which is used as base for a copy on write image; the copy on write image only stores the modified data

fmt

  is the disk image format. It is guessed automatically in most cases. The following formats are supported:

  `raw`

    Raw disk image format (default). This format has the advantage of being simple and easily exportable to all other emulators. If your file system supports holes (for example in ext2 or ext3 on Linux), then only the written sectors will reserve space. Use `qemu-img info` to know the real size used by the image or `ls -ls` on Unix/Linux.

  `qcow`

    QEMU image format, the most versatile format. Use it to have smaller images (useful if your filesystem does not supports holes, for example on Windows), optional AES encryption and zlib based compression.

  `cow`

    User Mode Linux Copy On Write image format. Used to be the only growable image format in QEMU. It is supported only for compatibility with previous versions. It does not work on win32.

  `vmdk`

    VMware 3 and 4 compatible image format. Currently only supported as read-only.

  `cloop`

    Linux Compressed Loop image, useful only to reuse directly compressed CD-ROM images present for example in the Knoppix CD-ROMs.

size

  is the disk image size in kilobytes. Optional suffixes `M` (megabyte) and `G` (gigabyte) are supported

output_filename

  is the destination disk image filename

output_fmt

  is the destination format

-c

  indicates that target image must be compressed (qcow format only)

-e

  indicates that the target image must be encrypted (qcow format only)

Command description:

``create [-e] [-b base_image] [-f fmt] filename [size]'`

  Create the new disk image filename of size size and format fmt.

  If base_image is specified, then the image will record only the differences from base_image. No size needs to be specified in this case. base_image will never be modified unless you use the `commit` monitor command.

``commit [-f fmt] filename'`

  Commit the changes recorded in filename in its base image.

``convert [-c] [-e] [-f fmt] filename [-O output_fmt] output_filename'`

  Convert the disk image filename to disk image output_filename using format output_fmt. It can be optionnaly encrypted (`-e` option) or compressed (`-c` option).

  Only the format `qcow` supports encryption or compression. The compression is read-only. It means that if a compressed sector is rewritten, then it is rewritten as uncompressed data.

  Encryption uses the AES format which is very secure (128 bit keys). Use a long password (16 characters) to get maximum protection.

  Image conversion is also useful to get smaller image when using a growable format such as `qcow` or `cow`: the empty sectors are detected and suppressed from the destination image.

``info [-f fmt] filename'`

  Give information about the disk image filename. Use it in particular to know the size reserved on disk which can be different from the displayed size.

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## 3.7 Network emulation

QEMU simulates up to 6 networks cards (NE2000 boards). Each card can be connected to a specific host network interface.

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### 3.7.1 Using tun/tap network interface

This is the standard way to emulate network. QEMU adds a virtual network device on your host (called `tun0`), and you can then configure it as if it was a real ethernet card.

As an example, you can download the ``linux-test-xxx.tar.gz'` archive and copy the script ``qemu-ifup'` in ``/etc'` and configure properly `sudo` so that the command `ifconfig` contained in ``qemu-ifup'` can be executed as root. You must verify that your host kernel supports the TUN/TAP network interfaces: the device ``/dev/net/tun'` must be present.

See Direct Linux Boot to have an example of network use with a Linux distribution.

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### 3.7.2 Using the user mode network stack

By using the option ``-user-net'` or if you have no tun/tap init script, QEMU uses a completely user mode network stack (you don't need root priviledge to use the virtual network). The virtual network configuration is the following:

    QEMU Virtual Machine    <------>  Firewall/DHCP server <-----> Internet
         (10.0.2.x)            |          (10.0.2.2)
                               |
                               ---->  DNS server (10.0.2.3)
                               |
                               ---->  SMB server (10.0.2.4)

The QEMU VM behaves as if it was behind a firewall which blocks all incoming connections. You can use a DHCP client to automatically configure the network in the QEMU VM.

In order to check that the user mode network is working, you can ping the address 10.0.2.2 and verify that you got an address in the range 10.0.2.x from the QEMU virtual DHCP server.

Note that `ping` is not supported reliably to the internet as it would require root priviledges. It means you can only ping the local router (10.0.2.2).

When using the built-in TFTP server, the router is also the TFTP server.

When using the ``-redir'` option, TCP or UDP connections can be redirected from the host to the guest. It allows for example to redirect X11, telnet or SSH connections.

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## 3.8 Direct Linux Boot

This section explains how to launch a Linux kernel inside QEMU without having to make a full bootable image. It is very useful for fast Linux kernel testing. The QEMU network configuration is also explained.

1. Download the archive ``linux-test-xxx.tar.gz'` containing a Linux kernel and a disk image.
2. Optional: If you want network support (for example to launch X11 examples), you must copy the script ``qemu-ifup'` in ``/etc'` and configure properly `sudo` so that the command `ifconfig` contained in ``qemu-ifup'` can be executed as root. You must verify that your host kernel supports the TUN/TAP network interfaces: the device ``/dev/net/tun'` must be present.

   When network is enabled, there is a virtual network connection between the host kernel and the emulated kernel. The emulated kernel is seen from the host kernel at IP address 172.20.0.2 and the host kernel is seen from the emulated kernel at IP address 172.20.0.1.

3. Launch `qemu.sh`. You should have the following output:

       > ./qemu.sh
       Connected to host network interface: tun0
       Linux version 2.4.21 (bellard@voyager.localdomain) (gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #5 Tue Nov 11 18:18:53 CET 2003
       BIOS-provided physical RAM map:
        BIOS-e801: 0000000000000000 - 000000000009f000 (usable)
        BIOS-e801: 0000000000100000 - 0000000002000000 (usable)
       32MB LOWMEM available.
       On node 0 totalpages: 8192
       zone(0): 4096 pages.
       zone(1): 4096 pages.
       zone(2): 0 pages.
       Kernel command line: root=/dev/hda sb=0x220,5,1,5 ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe console=ttyS0
       ide_setup: ide2=noprobe
       ide_setup: ide3=noprobe
       ide_setup: ide4=noprobe
       ide_setup: ide5=noprobe
       Initializing CPU#0
       Detected 2399.621 MHz processor.
       Console: colour EGA 80x25
       Calibrating delay loop... 4744.80 BogoMIPS
       Memory: 28872k/32768k available (1210k kernel code, 3508k reserved, 266k data, 64k init, 0k highmem)
       Dentry cache hash table entries: 4096 (order: 3, 32768 bytes)
       Inode cache hash table entries: 2048 (order: 2, 16384 bytes)
       Mount cache hash table entries: 512 (order: 0, 4096 bytes)
       Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
       Page-cache hash table entries: 8192 (order: 3, 32768 bytes)
       CPU: Intel Pentium Pro stepping 03
       Checking 'hlt' instruction... OK.
       POSIX conformance testing by UNIFIX
       Linux NET4.0 for Linux 2.4
       Based upon Swansea University Computer Society NET3.039
       Initializing RT netlink socket
       apm: BIOS not found.
       Starting kswapd
       Journalled Block Device driver loaded
       Detected PS/2 Mouse Port.
       pty: 256 Unix98 ptys configured
       Serial driver version 5.05c (2001-07-08) with no serial options enabled
       ttyS00 at 0x03f8 (irq = 4) is a 16450
       ne.c:v1.10 9/23/94 Donald Becker (becker@scyld.com)
       Last modified Nov 1, 2000 by Paul Gortmaker
       NE*000 ethercard probe at 0x300: 52 54 00 12 34 56
       eth0: NE2000 found at 0x300, using IRQ 9.
       RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
       Uniform Multi-Platform E-IDE driver Revision: 7.00beta4-2.4
       ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
       hda: QEMU HARDDISK, ATA DISK drive
       ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
       hda: attached ide-disk driver.
       hda: 20480 sectors (10 MB) w/256KiB Cache, CHS=20/16/63
       Partition check:
        hda:
       Soundblaster audio driver Copyright (C) by Hannu Savolainen 1993-1996
       NET4: Linux TCP/IP 1.0 for NET4.0
       IP Protocols: ICMP, UDP, TCP, IGMP
       IP: routing cache hash table of 512 buckets, 4Kbytes
       TCP: Hash tables configured (established 2048 bind 4096)
       NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
       EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended
       VFS: Mounted root (ext2 filesystem).
       Freeing unused kernel memory: 64k freed

       Linux version 2.4.21 (bellard@voyager.localdomain) (gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #5 Tue Nov 11 18:18:53 CET 2003

       QEMU Linux test distribution (based on Redhat 9)

       Type 'exit' to halt the system

       sh-2.05b#

4. Then you can play with the kernel inside the virtual serial console. You can launch `ls` for example. Type `Ctrl-a h` to have an help about the keys you can type inside the virtual serial console. In particular, use `Ctrl-a x` to exit QEMU and use `Ctrl-a b` as the Magic SysRq key.
5. If the network is enabled, launch the script ``/etc/linuxrc'` in the emulator (don't forget the leading dot):

       . /etc/linuxrc

   Then enable X11 connections on your PC from the emulated Linux:

       xhost +172.20.0.2

   You can now launch ``xterm'` or ``xlogo'` and verify that you have a real Virtual Linux system !

NOTES:

1. A 2.5.74 kernel is also included in the archive. Just replace the bzImage in qemu.sh to try it.
2. In order to exit cleanly from qemu, you can do a shutdown inside qemu. qemu will automatically exit when the Linux shutdown is done.
3. You can boot slightly faster by disabling the probe of non present IDE interfaces. To do so, add the following options on the kernel command line:

       ide1=noprobe ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe

4. The example disk image is a modified version of the one made by Kevin Lawton for the plex86 Project (www.plex86.org).

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## 3.9 GDB usage

QEMU has a primitive support to work with gdb, so that you can do 'Ctrl-C' while the virtual machine is running and inspect its state.

In order to use gdb, launch qemu with the '-s' option. It will wait for a gdb connection:

    > qemu -s -kernel arch/i386/boot/bzImage -hda root-2.4.20.img -append "root=/dev/hda"
    Connected to host network interface: tun0
    Waiting gdb connection on port 1234

Then launch gdb on the 'vmlinux' executable:

    > gdb vmlinux

In gdb, connect to QEMU:

    (gdb) target remote localhost:1234

Then you can use gdb normally. For example, type 'c' to launch the kernel:

    (gdb) c

Here are some useful tips in order to use gdb on system code:

1. Use `info reg` to display all the CPU registers.
2. Use `x/10i $eip` to display the code at the PC position.
3. Use `set architecture i8086` to dump 16 bit code. Then use `x/10i $cs*16+*eip` to dump the code at the PC position.

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## 3.10 Target OS specific information

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### 3.10.1 Linux

To have access to SVGA graphic modes under X11, use the `vesa` or the `cirrus` X11 driver. For optimal performances, use 16 bit color depth in the guest and the host OS.

When using a 2.6 guest Linux kernel, you should add the option `clock=pit` on the kernel command line because the 2.6 Linux kernels make very strict real time clock checks by default that QEMU cannot simulate exactly.

When using a 2.6 guest Linux kernel, verify that the 4G/4G patch is not activated because QEMU is slower with this patch. The QEMU Accelerator Module is also much slower in this case. Earlier Fedora Core 3 Linux kernel (< 2.6.9-1.724_FC3) were known to incorporte this patch by default. Newer kernels don't have it.

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### 3.10.2 Windows

If you have a slow host, using Windows 95 is better as it gives the best speed. Windows 2000 is also a good choice.

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#### 3.10.2.1 SVGA graphic modes support

QEMU emulates a Cirrus Logic GD5446 Video card. All Windows versions starting from Windows 95 should recognize and use this graphic card. For optimal performances, use 16 bit color depth in the guest and the host OS.

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#### 3.10.2.2 CPU usage reduction

Windows 9x does not correctly use the CPU HLT instruction. The result is that it takes host CPU cycles even when idle. You can install the utility from http://www.user.cityline.ru/~maxamn/amnhltm.zip to solve this problem. Note that no such tool is needed for NT, 2000 or XP.

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#### 3.10.2.3 Windows 2000 disk full problem

Windows 2000 has a bug which gives a disk full problem during its installation. When installing it, use the ``-win2k-hack'` QEMU option to enable a specific workaround. After Windows 2000 is installed, you no longer need this option (this option slows down the IDE transfers).

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#### 3.10.2.4 Windows XP security problems

Some releases of Windows XP install correctly but give a security error when booting:

    A problem is preventing Windows from accurately checking the
    license for this computer. Error code: 0x800703e6.

The only known workaround is to boot in Safe mode without networking support.

Future QEMU releases are likely to correct this bug.

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### 3.10.3 MS-DOS and FreeDOS

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#### 3.10.3.1 CPU usage reduction

DOS does not correctly use the CPU HLT instruction. The result is that it takes host CPU cycles even when idle. You can install the utility from http://www.vmware.com/software/dosidle210.zip to solve this problem.

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# 4. QEMU PowerPC System emulator invocation

Use the executable ``qemu-system-ppc'` to simulate a complete PREP or PowerMac PowerPC system.

QEMU emulates the following PowerMac peripherals:

QEMU emulates the following PREP peripherals:

QEMU uses the Open Hack'Ware Open Firmware Compatible BIOS available at http://site.voila.fr/jmayer/OpenHackWare/index.htm.

You can read the qemu PC system emulation chapter to have more informations about QEMU usage.

The following options are specific to the PowerPC emulation:

``-prep'`

  Simulate a PREP system (default is PowerMAC)

``-g WxH[xDEPTH]'`

  Set the initial VGA graphic mode. The default is 800x600x15.

More information is available at http://jocelyn.mayer.free.fr/qemu-ppc/.

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# 5. Sparc32 System emulator invocation

Use the executable ``qemu-system-sparc'` to simulate a JavaStation (sun4m architecture). The emulation is somewhat complete.

QEMU emulates the following sun4m peripherals:

The number of peripherals is fixed in the architecture.

QEMU uses the Proll, a PROM replacement available at http://people.redhat.com/zaitcev/linux/. The required QEMU-specific patches are included with the sources.

A sample Linux 2.6 series kernel and ram disk image are available on the QEMU web site. Please note that currently neither Linux 2.4 series, NetBSD, nor OpenBSD kernels work.

The following options are specific to the Sparc emulation:

``-g WxH'`

  Set the initial TCX graphic mode. The default is 1024x768.

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# 6. Sparc64 System emulator invocation

Use the executable ``qemu-system-sparc64'` to simulate a Sun4u machine. The emulator is not usable for anything yet.

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# 7. MIPS System emulator invocation

Use the executable ``qemu-system-mips'` to simulate a MIPS machine. The emulator begins to launch a Linux kernel.

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# 8. QEMU User space emulator invocation

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## 8.1 Quick Start

In order to launch a Linux process, QEMU needs the process executable itself and all the target (x86) dynamic libraries used by it.

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## 8.2 Wine launch

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## 8.3 Command line options

    usage: qemu-i386 [-h] [-d] [-L path] [-s size] program [arguments...]

``-h'`

  Print the help

``-L path'`

  Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)

``-s size'`

  Set the x86 stack size in bytes (default=524288)

Debug options:

``-d'`

  Activate log (logfile=/tmp/qemu.log)

``-p pagesize'`

  Act as if the host page size was 'pagesize' bytes

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# 9. Compilation from the sources

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## 9.1 Linux/Unix

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### 9.1.1 Compilation

First you must decompress the sources:

    cd /tmp
    tar zxvf qemu-x.y.z.tar.gz
    cd qemu-x.y.z

Then you configure QEMU and build it (usually no options are needed):

    ./configure
    make

Then type as root user:

    make install

to install QEMU in ``/usr/local'`.

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### 9.1.2 Tested tool versions

In order to compile QEMU succesfully, it is very important that you have the right tools. The most important one is gcc. I cannot guaranty that QEMU works if you do not use a tested gcc version. Look at 'configure' and 'Makefile' if you want to make a different gcc version work.

    host      gcc      binutils      glibc    linux       distribution
    ----------------------------------------------------------------------
    x86       3.2      2.13.2        2.1.3    2.4.18
              2.96     2.11.93.0.2   2.2.5    2.4.18      Red Hat 7.3
              3.2.2    2.13.90.0.18  2.3.2    2.4.20      Red Hat 9

    PowerPC   3.3 [4]  2.13.90.0.18  2.3.1    2.4.20briq
              3.2

    Alpha     3.3 [1]  2.14.90.0.4   2.2.5    2.2.20 [2]  Debian 3.0

    Sparc32   2.95.4   2.12.90.0.1   2.2.5    2.4.18      Debian 3.0

    ARM       2.95.4   2.12.90.0.1   2.2.5    2.4.9 [3]   Debian 3.0

    [1] On Alpha, QEMU needs the gcc 'visibility' attribute only available
        for gcc version >= 3.3.
    [2] Linux >= 2.4.20 is necessary for precise exception support
        (untested).
    [3] 2.4.9-ac10-rmk2-np1-cerf2

    [4] gcc 2.95.x generates invalid code when using too many register
    variables. You must use gcc 3.x on PowerPC.

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## 9.2 Windows

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## 9.3 Cross compilation for Windows with Linux

Note: Currently, Wine does not seem able to launch QEMU for Win32.

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## 9.4 Mac OS X

The Mac OS X patches are not fully merged in QEMU, so you should look at the QEMU mailing list archive to have all the necessary information.

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# About This Document

This document was generated by Charlie & on October, 12 2005 using texi2html 1.76.

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