\input texinfo @c -*- texinfo -*-
-@settitle QEMU x86 Emulator Reference Documentation
+@iftex
+@settitle QEMU CPU Emulator User Documentation
@titlepage
@sp 7
-@center @titlefont{QEMU x86 Emulator Reference Documentation}
+@center @titlefont{QEMU CPU Emulator User Documentation}
@sp 3
@end titlepage
+@end iftex
@chapter Introduction
-QEMU is an x86 processor emulator. Its purpose is to run x86 Linux
-processes on non-x86 Linux architectures such as PowerPC or ARM. By
-using dynamic translation it achieves a reasonnable speed while being
-easy to port on new host CPUs. An obviously interesting x86 only process
-is 'wine' (Windows emulation).
+@section Features
-QEMU features:
+QEMU is a FAST! processor emulator using dynamic translation to
+achieve good emulation speed.
-@itemize
+QEMU has two operating modes:
-@item User space only x86 emulator.
+@itemize @minus
-@item Currently ported on i386 and PowerPC.
+@item
+Full system emulation. In this mode, QEMU emulates a full system (for
+example a PC), including a processor and various peripherials. It can
+be used to launch different Operating Systems without rebooting the
+PC or to debug system code.
-@item Using dynamic translation for reasonnable speed.
+@item
+User mode emulation (Linux host only). In this mode, QEMU can launch
+Linux processes compiled for one CPU on another CPU. It can be used to
+launch the Wine Windows API emulator (@url{http://www.winehq.org}) or
+to ease cross-compilation and cross-debugging.
-@item The virtual x86 CPU supports 16 bit and 32 bit addressing with segmentation.
-User space LDT and GDT are emulated.
+@end itemize
+
+As QEMU requires no host kernel driver to run, it is very safe and
+easy to use.
+
+For system emulation, the following hardware targets are supported:
+@itemize
+@item PC (x86 processor)
+@item PREP (PowerPC processor)
+@end itemize
+
+For user emulation, x86, PowerPC, ARM, and SPARC CPUs are supported.
-@item Generic Linux system call converter, including most ioctls.
+@chapter Installation
-@item clone() emulation using native CPU clone() to use Linux scheduler for threads.
+@section Linux
-@item Accurate signal handling by remapping host signals to virtual x86 signals.
+If you want to compile QEMU, please read the @file{README} which gives
+the related information. Otherwise just download the binary
+distribution (@file{qemu-XXX-i386.tar.gz}) and untar it as root in
+@file{/}:
-@item The virtual x86 CPU is a library (@code{libqemu}) which can be used
-in other projects.
+@example
+su
+cd /
+tar zxvf /tmp/qemu-XXX-i386.tar.gz
+@end example
-@item An extensive Linux x86 CPU test program is included @file{tests/test-i386}.
-It can be used to test other x86 virtual CPUs.
+@section Windows
+w
+@itemize
+@item Install the current versions of MSYS and MinGW from
+@url{http://www.mingw.org/}. You can find detailed installation
+instructions in the download section and the FAQ.
+
+@item Download
+the MinGW development library of SDL 1.2.x
+(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
+@url{http://www.libsdl.org}. Unpack it in a temporary place, and
+unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
+directory. Edit the @file{sdl-config} script so that it gives the
+correct SDL directory when invoked.
+
+@item Extract the current version of QEMU.
+
+@item Start the MSYS shell (file @file{msys.bat}).
+
+@item Change to the QEMU directory. Launch @file{./configure} and
+@file{make}. If you have problems using SDL, verify that
+@file{sdl-config} can be launched from the MSYS command line.
+
+@item You can install QEMU in @file{Program Files/Qemu} by typing
+@file{make install}. Don't forget to copy @file{SDL.dll} in
+@file{Program Files/Qemu}.
@end itemize
-Current QEMU Limitations:
+@section Cross compilation for Windows with Linux
+
+@itemize
+@item
+Install the MinGW cross compilation tools available at
+@url{http://www.mingw.org/}.
+
+@item
+Install the Win32 version of SDL (@url{http://www.libsdl.org}) by
+unpacking @file{i386-mingw32msvc.tar.gz}. Set up the PATH environment
+variable so that @file{i386-mingw32msvc-sdl-config} can be launched by
+the QEMU configuration script.
+
+@item
+Configure QEMU for Windows cross compilation:
+@example
+./configure --enable-mingw32
+@end example
+If necessary, you can change the cross-prefix according to the prefix
+choosen for the MinGW tools with --cross-prefix. You can also use
+--prefix to set the Win32 install path.
+
+@item You can install QEMU in the installation directory by typing
+@file{make install}. Don't forget to copy @file{SDL.dll} in the
+installation directory.
+
+@end itemize
-@itemize
+Note: Currently, Wine does not seem able to launch
+QEMU for Win32.
-@item Not all x86 exceptions are precise (yet). [Very few programs need that].
+@section Mac OS X
-@item Not self virtualizable (yet). [You cannot launch qemu with qemu on the same CPU].
+Mac OS X is currently not supported.
-@item No support for self modifying code (yet). [Very few programs need that, a notable exception is QEMU itself !].
+@chapter QEMU PC System emulator invocation
-@item No VM86 mode (yet), althought the virtual
-CPU has support for most of it. [VM86 support is useful to launch old 16
-bit DOS programs with dosemu or wine].
+@section Introduction
-@item No SSE/MMX support (yet).
+@c man begin DESCRIPTION
-@item No x86-64 support.
+The QEMU System emulator simulates a complete PC.
-@item Some Linux syscalls are missing.
+In order to meet specific user needs, two versions of QEMU are
+available:
-@item The x86 segment limits and access rights are not tested at every
-memory access (and will never be to have good performances).
+@enumerate
-@item On non x86 host CPUs, @code{double}s are used instead of the non standard
-10 byte @code{long double}s of x86 for floating point emulation to get
-maximum performances.
+@item
+@code{qemu-fast} uses the host Memory Management Unit (MMU) to simulate
+the x86 MMU. It is @emph{fast} but has limitations because the whole 4 GB
+address space cannot be used and some memory mapped peripherials
+cannot be emulated accurately yet. Therefore, a specific Linux kernel
+must be used (@xref{linux_compile}).
+@item
+@code{qemu} uses a software MMU. It is about @emph{two times
+slower} but gives a more accurate emulation.
+
+@end enumerate
+
+QEMU emulates the following PC peripherials:
+
+@itemize @minus
+@item
+VGA (hardware level, including all non standard modes)
+@item
+PS/2 mouse and keyboard
+@item
+2 IDE interfaces with hard disk and CD-ROM support
+@item
+Floppy disk
+@item
+up to 6 NE2000 network adapters
+@item
+Serial port
+@item
+Soundblaster 16 card
@end itemize
-@chapter Invocation
+@c man end
@section 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.
+Download and uncompress the linux image (@file{linux.img}) and type:
-@itemize
+@example
+qemu linux.img
+@end example
-@item On x86, you can just try to launch any process by using the native
-libraries:
+Linux should boot and give you a prompt.
+
+@section Invocation
+
+@example
+@c man begin SYNOPSIS
+usage: qemu [options] [disk_image]
+@c man end
+@end example
+
+@c man begin OPTIONS
+@var{disk_image} is a raw hard disk image for IDE hard disk 0.
+
+General options:
+@table @option
+@item -fda file
+@item -fdb file
+Use @var{file} as floppy disk 0/1 image (@xref{disk_images}).
+
+@item -hda file
+@item -hdb file
+@item -hdc file
+@item -hdd file
+Use @var{file} as hard disk 0, 1, 2 or 3 image (@xref{disk_images}).
+
+@item -cdrom file
+Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and and
+@option{-cdrom} at the same time).
+
+@item -boot [a|c|d]
+Boot on floppy (a), hard disk (c) or CD-ROM (d). 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} (@xref{disk_images}).
+
+@item -m megs
+Set virtual RAM size to @var{megs} megabytes.
+
+@item -initrd file
+Use @var{file} as initial ram disk.
+
+@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 -enable-audio
+
+The SB16 emulation is disabled by default as it may give problems with
+Windows. You can enable it manually with this option.
+
+@end table
+
+Network options:
+
+@table @option
+
+@item -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.
+
+@item -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.
+
+@item -tun-fd fd
+Assumes @var{fd} talks to a tap/tun host network interface and use
+it. Read @url{http://bellard.org/qemu/tetrinet.html} to have an
+example of its use.
+
+@item -user-net
+(Experimental) Use the user mode network stack. This is the default if
+no tun/tap network init script is found.
+
+@item -dummy-net
+Use the dummy network stack: no packet will be received on the network
+cards.
+
+@end table
+
+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.
+
+@table @option
+
+@item -kernel bzImage
+Use @var{bzImage} as kernel image.
+
+@item -append cmdline
+Use @var{cmdline} as kernel command line
+
+@item -initrd file
+Use @var{file} as initial ram disk.
+
+@end table
+Debug options:
+@table @option
+@item -s
+Wait gdb connection to port 1234 (@xref{gdb_usage}).
+@item -p port
+Change gdb connection port.
+@item -S
+Do not start CPU at startup (you must type 'c' in the monitor).
+@item -d
+Output log in /tmp/qemu.log
+@end table
+
+During emulation, if you are using the serial console, use @key{C-a h}
+to get terminal commands:
+
+@table @key
+@item C-a h
+Print this help
+@item C-a x
+Exit emulatior
+@item C-a s
+Save disk data back to file (if -snapshot)
+@item C-a b
+Send break (magic sysrq in Linux)
+@item C-a c
+Switch between console and monitor
+@item C-a C-a
+Send C-a
+@end table
+@c man end
+
+@ignore
+
+@setfilename qemu
+@settitle QEMU System Emulator
+
+@c man begin SEEALSO
+The HTML documentation of QEMU for more precise information and Linux
+user mode emulator invocation.
+@c man end
+
+@c man begin AUTHOR
+Fabrice Bellard
+@c man end
+
+@end ignore
+
+@end ignore
+
+
+@section QEMU Monitor
+
+The QEMU monitor is used to give complex commands to the QEMU
+emulator. You can use it to:
+
+@itemize @minus
+
+@item
+Remove or insert removable medias images
+(such as CD-ROM or floppies)
+
+@item
+Freeze/unfreeze the Virtual Machine (VM) and save or restore its state
+from a disk file.
+
+@item Inspect the VM state without an external debugger.
+
+@end itemize
+
+@subsection Commands
+
+The following commands are available:
+
+@table @option
+
+@item help or ? [cmd]
+Show the help for all commands or just for command @var{cmd}.
+
+@item commit
+Commit changes to the disk images (if -snapshot is used)
+
+@item info subcommand
+show various information about the system state
+
+@table @option
+@item info network
+show the network state
+@item info block
+show the block devices
+@item info registers
+show the cpu registers
+@item info history
+show the command line history
+@end table
+
+@item q or quit
+Quit the emulator.
+
+@item eject [-f] device
+Eject a removable media (use -f to force it).
+
+@item change device filename
+Change a removable media.
+
+@item screendump filename
+Save screen into PPM image @var{filename}.
+
+@item log item1[,...]
+Activate logging of the specified items to @file{/tmp/qemu.log}.
+
+@item savevm filename
+Save the whole virtual machine state to @var{filename}.
+
+@item loadvm filename
+Restore the whole virtual machine state from @var{filename}.
+
+@item stop
+Stop emulation.
+
+@item c or cont
+Resume emulation.
+
+@item gdbserver [port]
+Start gdbserver session (default port=1234)
+
+@item x/fmt addr
+Virtual memory dump starting at @var{addr}.
+
+@item xp /fmt addr
+Physical memory dump starting at @var{addr}.
+
+@var{fmt} is a format which tells the command how to format the
+data. Its syntax is: @option{/@{count@}@{format@}@{size@}}
+
+@table @var
+@item count
+is the number of items to be dumped.
+
+@item format
+can be x (hexa), d (signed decimal), u (unsigned decimal), o (octal),
+c (char) or i (asm instruction).
+
+@item size
+can be b (8 bits), h (16 bits), w (32 bits) or g (64 bits). On x86,
+@code{h} or @code{w} can be specified with the @code{i} format to
+respectively select 16 or 32 bit code instruction size.
+
+@end table
+
+Examples:
+@itemize
+@item
+Dump 10 instructions at the current instruction pointer:
@example
-qemu -L / /bin/ls
+(qemu) x/10i $eip
+0x90107063: ret
+0x90107064: sti
+0x90107065: lea 0x0(%esi,1),%esi
+0x90107069: lea 0x0(%edi,1),%edi
+0x90107070: ret
+0x90107071: jmp 0x90107080
+0x90107073: nop
+0x90107074: nop
+0x90107075: nop
+0x90107076: nop
@end example
-@code{-L /} tells that the x86 dynamic linker must be searched with a
-@file{/} prefix.
+@item
+Dump 80 16 bit values at the start of the video memory.
+@example
+(qemu) xp/80hx 0xb8000
+0x000b8000: 0x0b50 0x0b6c 0x0b65 0x0b78 0x0b38 0x0b36 0x0b2f 0x0b42
+0x000b8010: 0x0b6f 0x0b63 0x0b68 0x0b73 0x0b20 0x0b56 0x0b47 0x0b41
+0x000b8020: 0x0b42 0x0b69 0x0b6f 0x0b73 0x0b20 0x0b63 0x0b75 0x0b72
+0x000b8030: 0x0b72 0x0b65 0x0b6e 0x0b74 0x0b2d 0x0b63 0x0b76 0x0b73
+0x000b8040: 0x0b20 0x0b30 0x0b35 0x0b20 0x0b4e 0x0b6f 0x0b76 0x0b20
+0x000b8050: 0x0b32 0x0b30 0x0b30 0x0b33 0x0720 0x0720 0x0720 0x0720
+0x000b8060: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+0x000b8070: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+0x000b8080: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+@end example
+@end itemize
+@item p or print/fmt expr
-@item On non x86 CPUs, you need first to download at least an x86 glibc
-(@file{qemu-i386-glibc21.tar.gz} on the QEMU web page). Then you can
-launch the precompiled @file{ls} x86 executable:
+Print expression value. Only the @var{format} part of @var{fmt} is
+used.
+
+@end table
+
+@subsection Integer expressions
+
+The monitor understands integers expressions for every integer
+argument. You can use register names to get the value of specifics
+CPU registers by prefixing them with @emph{$}.
+
+@node disk_images
+@section Disk Images
+
+@subsection Raw disk images
+
+The disk images can simply be raw images of the hard disk. You can
+create them with the command:
@example
-qemu /usr/local/qemu-i386/bin/ls
+dd if=/dev/zero of=myimage bs=1024 count=mysize
@end example
-You can look at @file{/usr/local/qemu-i386/bin/qemu-conf.sh} so that QEMU is automatically
-launched by the Linux kernel when you try to launch x86 executables. It
-requires the @code{binfmt_misc} module in the Linux kernel.
+where @var{myimage} is the image filename and @var{mysize} is its size
+in kilobytes.
-@end itemize
+@subsection Snapshot mode
-@section Command line options
+If you use the option @option{-snapshot}, all disk images are
+considered as read only. When sectors in written, they are written in
+a temporary file created in @file{/tmp}. You can however force the
+write back to the raw disk images by pressing @key{C-a s}.
+
+NOTE: The snapshot mode only works with raw disk images.
+
+@subsection Copy On Write disk images
+
+QEMU also supports user mode Linux
+(@url{http://user-mode-linux.sourceforge.net/}) Copy On Write (COW)
+disk images. The COW disk images are much smaller than normal images
+as they store only modified sectors. They also permit the use of the
+same disk image template for many users.
+
+To create a COW disk images, use the command:
@example
-usage: qemu [-h] [-d] [-L path] [-s size] program [arguments...]
+qemu-mkcow -f myrawimage.bin mycowimage.cow
@end example
-@table @samp
-@item -h
-Print the help
-@item -d
-Activate log (logfile=/tmp/qemu.log)
-@item -L path
-Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)
-@item -s size
-Set the x86 stack size in bytes (default=524288)
-@end table
+@file{myrawimage.bin} is a raw image you want to use as original disk
+image. It will never be written to.
+
+@file{mycowimage.cow} is the COW disk image which is created by
+@code{qemu-mkcow}. You can use it directly with the @option{-hdx}
+options. You must not modify the original raw disk image if you use
+COW images, as COW images only store the modified sectors from the raw
+disk image. QEMU stores the original raw disk image name and its
+modified time in the COW disk image so that chances of mistakes are
+reduced.
-@chapter QEMU Internals
+If the raw disk image is not read-only, by pressing @key{C-a s} you
+can flush the COW disk image back into the raw disk image, as in
+snapshot mode.
-@section QEMU compared to other emulators
+COW disk images can also be created without a corresponding raw disk
+image. It is useful to have a big initial virtual disk image without
+using much disk space. Use:
-Unlike bochs [3], QEMU emulates only a user space x86 CPU. It means that
-you cannot launch an operating system with it. The benefit is that it is
-simpler and faster due to the fact that some of the low level CPU state
-can be ignored (in particular, no virtual memory needs to be emulated).
+@example
+qemu-mkcow mycowimage.cow 1024
+@end example
+
+to create a 1 gigabyte empty COW disk image.
+
+NOTES:
+@enumerate
+@item
+COW disk images must be created on file systems supporting
+@emph{holes} such as ext2 or ext3.
+@item
+Since holes are used, the displayed size of the COW disk image is not
+the real one. To know it, use the @code{ls -ls} command.
+@end enumerate
-Like Valgrind [2], QEMU does user space emulation and dynamic
-translation. Valgrind is mainly a memory debugger while QEMU has no
-support for it (QEMU could be used to detect out of bound memory accesses
-as Valgrind, but it has no support to track uninitialised data as
-Valgrind does). Valgrind dynamic translator generates better code than
-QEMU (in particular it does register allocation) but it is closely tied
-to an x86 host.
+@section Network emulation
-EM86 [4] is the closest project to QEMU (and QEMU still uses some of its
-code, in particular the ELF file loader). EM86 was limited to an alpha
-host and used a proprietary and slow interpreter (the interpreter part
-of the FX!32 Digital Win32 code translator [5]).
+QEMU simulates up to 6 networks cards (NE2000 boards). Each card can
+be connected to a specific host network interface.
-@section Portable dynamic translation
+@subsection Using tun/tap network interface
-QEMU is a dynamic translator. When it first encounters a piece of code,
-it converts it to the host instruction set. Usually dynamic translators
-are very complicated and highly CPU dependant. QEMU uses some tricks
-which make it relatively easily portable and simple while achieving good
-performances.
+This is the standard way to emulate network. QEMU adds a virtual
+network device on your host (called @code{tun0}), and you can then
+configure it as if it was a real ethernet card.
-The basic idea is to split every x86 instruction into fewer simpler
-instructions. Each simple instruction is implemented by a piece of C
-code (see @file{op-i386.c}). Then a compile time tool (@file{dyngen})
-takes the corresponding object file (@file{op-i386.o}) to generate a
-dynamic code generator which concatenates the simple instructions to
-build a function (see @file{op-i386.h:dyngen_code()}).
+As an example, you can download the @file{linux-test-xxx.tar.gz}
+archive and copy the script @file{qemu-ifup} in @file{/etc} and
+configure properly @code{sudo} so that the command @code{ifconfig}
+contained in @file{qemu-ifup} can be executed as root. You must verify
+that your host kernel supports the TUN/TAP network interfaces: the
+device @file{/dev/net/tun} must be present.
-In essence, the process is similar to [1], but more work is done at
-compile time.
+See @ref{direct_linux_boot} to have an example of network use with a
+Linux distribution.
-A key idea to get optimal performances is that constant parameters can
-be passed to the simple operations. For that purpose, dummy ELF
-relocations are generated with gcc for each constant parameter. Then,
-the tool (@file{dyngen}) can locate the relocations and generate the
-appriopriate C code to resolve them when building the dynamic code.
+@subsection Using the user mode network stack
-That way, QEMU is no more difficult to port than a dynamic linker.
+This is @emph{experimental} (version 0.5.4). You must configure qemu
+with @code{--enable-slirp}. Then by using the option
+@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:
+
+@example
+
+QEMU Virtual Machine <------> Firewall/DHCP server <-----> Internet
+ (10.0.2.x) | (10.0.2.2)
+ |
+ ----> DNS
+ (10.0.2.3)
+@end example
-To go even faster, GCC static register variables are used to keep the
-state of the virtual CPU.
+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.
-@section Register allocation
+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.
-Since QEMU uses fixed simple instructions, no efficient register
-allocation can be done. However, because RISC CPUs have a lot of
-register, most of the virtual CPU state can be put in registers without
-doing complicated register allocation.
+@node direct_linux_boot
+@section Direct Linux Boot
-@section Condition code optimisations
+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.
-Good CPU condition codes emulation (@code{EFLAGS} register on x86) is a
-critical point to get good performances. QEMU uses lazy condition code
-evaluation: instead of computing the condition codes after each x86
-instruction, it store justs one operand (called @code{CC_CRC}), the
-result (called @code{CC_DST}) and the type of operation (called
-@code{CC_OP}).
+@enumerate
+@item
+Download the archive @file{linux-test-xxx.tar.gz} containing a Linux
+kernel and a disk image.
-@code{CC_OP} is almost never explicitely set in the generated code
-because it is known at translation time.
+@item Optional: If you want network support (for example to launch X11 examples), you
+must copy the script @file{qemu-ifup} in @file{/etc} and configure
+properly @code{sudo} so that the command @code{ifconfig} contained in
+@file{qemu-ifup} can be executed as root. You must verify that your host
+kernel supports the TUN/TAP network interfaces: the device
+@file{/dev/net/tun} must be present.
-In order to increase performances, a backward pass is performed on the
-generated simple instructions (see
-@code{translate-i386.c:optimize_flags()}). When it can be proved that
-the condition codes are not needed by the next instructions, no
-condition codes are computed at all.
+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.
+
+@item Launch @code{qemu.sh}. You should have the following output:
+
+@example
+> ./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#
+@end example
+
+@item
+Then you can play with the kernel inside the virtual serial console. You
+can launch @code{ls} for example. Type @key{Ctrl-a h} to have an help
+about the keys you can type inside the virtual serial console. In
+particular, use @key{Ctrl-a x} to exit QEMU and use @key{Ctrl-a b} as
+the Magic SysRq key.
+
+@item
+If the network is enabled, launch the script @file{/etc/linuxrc} in the
+emulator (don't forget the leading dot):
+@example
+. /etc/linuxrc
+@end example
-@section Translation CPU state optimisations
+Then enable X11 connections on your PC from the emulated Linux:
+@example
+xhost +172.20.0.2
+@end example
-The x86 CPU has many internal states which change the way it evaluates
-instructions. In order to achieve a good speed, the translation phase
-considers that some state information of the virtual x86 CPU cannot
-change in it. For example, if the SS, DS and ES segments have a zero
-base, then the translator does not even generate an addition for the
-segment base.
+You can now launch @file{xterm} or @file{xlogo} and verify that you have
+a real Virtual Linux system !
-[The FPU stack pointer register is not handled that way yet].
+@end enumerate
-@section Translation cache
+NOTES:
+@enumerate
+@item
+A 2.5.74 kernel is also included in the archive. Just
+replace the bzImage in qemu.sh to try it.
-A 2MByte cache holds the most recently used translations. For
-simplicity, it is completely flushed when it is full. A translation unit
-contains just a single basic block (a block of x86 instructions
-terminated by a jump or by a virtual CPU state change which the
-translator cannot deduce statically).
+@item
+qemu-fast creates a temporary file in @var{$QEMU_TMPDIR} (@file{/tmp} is the
+default) containing all the simulated PC memory. If possible, try to use
+a temporary directory using the tmpfs filesystem to avoid too many
+unnecessary disk accesses.
-[Currently, the translated code is not patched if it jumps to another
-translated code].
+@item
+In order to exit cleanly from qemu, you can do a @emph{shutdown} inside
+qemu. qemu will automatically exit when the Linux shutdown is done.
-@section Exception support
+@item
+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:
+@example
+ide1=noprobe ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe
+@end example
-longjmp() is used when an exception such as division by zero is
-encountered. The host SIGSEGV and SIGBUS signal handlers are used to get
-invalid memory accesses.
+@item
+The example disk image is a modified version of the one made by Kevin
+Lawton for the plex86 Project (@url{www.plex86.org}).
-[Currently, the virtual CPU cannot retrieve the exact CPU state in some
-exceptions, although it could except for the @code{EFLAGS} register].
+@end enumerate
-@section Linux system call translation
+@node linux_compile
+@section Linux Kernel Compilation
-QEMU includes a generic system call translator for Linux. It means that
-the parameters of the system calls can be converted to fix the
-endianness and 32/64 bit issues. The IOCTLs are converted with a generic
-type description system (see @file{ioctls.h} and @file{thunk.c}).
+You can use any linux kernel with QEMU. However, if you want to use
+@code{qemu-fast} to get maximum performances, you must use a modified
+guest kernel. If you are using a 2.6 guest kernel, you can use
+directly the patch @file{linux-2.6-qemu-fast.patch} made by Rusty
+Russel available in the QEMU source archive. Otherwise, you can make the
+following changes @emph{by hand} to the Linux kernel:
-@section Linux signals
+@enumerate
+@item
+The kernel must be mapped at 0x90000000 (the default is
+0xc0000000). You must modify only two lines in the kernel source:
-Normal and real-time signals are queued along with their information
-(@code{siginfo_t}) as it is done in the Linux kernel. Then an interrupt
-request is done to the virtual CPU. When it is interrupted, one queued
-signal is handled by generating a stack frame in the virtual CPU as the
-Linux kernel does. The @code{sigreturn()} system call is emulated to return
-from the virtual signal handler.
+In @file{include/asm/page.h}, replace
+@example
+#define __PAGE_OFFSET (0xc0000000)
+@end example
+by
+@example
+#define __PAGE_OFFSET (0x90000000)
+@end example
-Some signals (such as SIGALRM) directly come from the host. Other
-signals are synthetized from the virtual CPU exceptions such as SIGFPE
-when a division by zero is done (see @code{main.c:cpu_loop()}).
+And in @file{arch/i386/vmlinux.lds}, replace
+@example
+ . = 0xc0000000 + 0x100000;
+@end example
+by
+@example
+ . = 0x90000000 + 0x100000;
+@end example
-The blocked signal mask is still handled by the host Linux kernel so
-that most signal system calls can be redirected directly to the host
-Linux kernel. Only the @code{sigaction()} and @code{sigreturn()} system
-calls need to be fully emulated (see @file{signal.c}).
+@item
+If you want to enable SMP (Symmetric Multi-Processing) support, you
+must make the following change in @file{include/asm/fixmap.h}. Replace
+@example
+#define FIXADDR_TOP (0xffffX000UL)
+@end example
+by
+@example
+#define FIXADDR_TOP (0xa7ffX000UL)
+@end example
+(X is 'e' or 'f' depending on the kernel version). Although you can
+use an SMP kernel with QEMU, it only supports one CPU.
-@section clone() system call and threads
+@item
+If you are not using a 2.6 kernel as host kernel but if you use a target
+2.6 kernel, you must also ensure that the 'HZ' define is set to 100
+(1000 is the default) as QEMU cannot currently emulate timers at
+frequencies greater than 100 Hz on host Linux systems < 2.6. In
+@file{include/asm/param.h}, replace:
-The Linux clone() system call is usually used to create a thread. QEMU
-uses the host clone() system call so that real host threads are created
-for each emulated thread. One virtual CPU instance is created for each
-thread.
+@example
+# define HZ 1000 /* Internal kernel timer frequency */
+@end example
+by
+@example
+# define HZ 100 /* Internal kernel timer frequency */
+@end example
-The virtual x86 CPU atomic operations are emulated with a global lock so
-that their semantic is preserved.
+@end enumerate
-@section Bibliography
+The file config-2.x.x gives the configuration of the example kernels.
-@table @asis
+Just type
+@example
+make bzImage
+@end example
-@item [1]
-@url{http://citeseer.nj.nec.com/piumarta98optimizing.html}, Optimizing
-direct threaded code by selective inlining (1998) by Ian Piumarta, Fabio
-Riccardi.
+As you would do to make a real kernel. Then you can use with QEMU
+exactly the same kernel as you would boot on your PC (in
+@file{arch/i386/boot/bzImage}).
-@item [2]
-@url{http://developer.kde.org/~sewardj/}, Valgrind, an open-source
-memory debugger for x86-GNU/Linux, by Julian Seward.
+@node gdb_usage
+@section GDB usage
-@item [3]
-@url{http://bochs.sourceforge.net/}, the Bochs IA-32 Emulator Project,
-by Kevin Lawton et al.
+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.
-@item [4]
-@url{http://www.cs.rose-hulman.edu/~donaldlf/em86/index.html}, the EM86
-x86 emulator on Alpha-Linux.
+In order to use gdb, launch qemu with the '-s' option. It will wait for a
+gdb connection:
+@example
+> 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
+@end example
-@item [5]
-@url{http://www.usenix.org/publications/library/proceedings/usenix-nt97/full_papers/chernoff/chernoff.pdf},
-DIGITAL FX!32: Running 32-Bit x86 Applications on Alpha NT, by Anton
-Chernoff and Ray Hookway.
+Then launch gdb on the 'vmlinux' executable:
+@example
+> gdb vmlinux
+@end example
-@end table
+In gdb, connect to QEMU:
+@example
+(gdb) target remote localhost:1234
+@end example
-@chapter Regression Tests
+Then you can use gdb normally. For example, type 'c' to launch the kernel:
+@example
+(gdb) c
+@end example
+
+Here are some useful tips in order to use gdb on system code:
+
+@enumerate
+@item
+Use @code{info reg} to display all the CPU registers.
+@item
+Use @code{x/10i $eip} to display the code at the PC position.
+@item
+Use @code{set architecture i8086} to dump 16 bit code. Then use
+@code{x/10i $cs*16+*eip} to dump the code at the PC position.
+@end enumerate
+
+@chapter QEMU PREP PowerPC System emulator invocation
+
+Use the executable @file{qemu-system-ppc} to simulate a complete PREP
+PowerPC system.
+
+QEMU emulates the following PREP peripherials:
+
+@itemize @minus
+@item
+2 IDE interfaces with hard disk and CD-ROM support
+@item
+Floppy disk
+@item
+up to 6 NE2000 network adapters
+@item
+Serial port
+@item
+PREP Non Volatile RAM
+@end itemize
+
+You can read the qemu PC system emulation chapter to have more
+informations about QEMU usage.
+
+More information is available at
+@url{http://jocelyn.mayer.free.fr/qemu-ppc/}.
+
+@chapter QEMU User space emulator invocation
+
+@section 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.
+
+@itemize
+
+@item On x86, you can just try to launch any process by using the native
+libraries:
+
+@example
+qemu-i386 -L / /bin/ls
+@end example
+
+@code{-L /} tells that the x86 dynamic linker must be searched with a
+@file{/} prefix.
+
+@item Since QEMU is also a linux process, you can launch qemu with qemu (NOTE: you can only do that if you compiled QEMU from the sources):
+
+@example
+qemu-i386 -L / qemu-i386 -L / /bin/ls
+@end example
+
+@item On non x86 CPUs, you need first to download at least an x86 glibc
+(@file{qemu-runtime-i386-XXX-.tar.gz} on the QEMU web page). Ensure that
+@code{LD_LIBRARY_PATH} is not set:
+
+@example
+unset LD_LIBRARY_PATH
+@end example
-In the directory @file{tests/}, various interesting x86 testing programs
-are available. There are used for regression testing.
+Then you can launch the precompiled @file{ls} x86 executable:
-@section @file{hello}
+@example
+qemu-i386 tests/i386/ls
+@end example
+You can look at @file{qemu-binfmt-conf.sh} so that
+QEMU is automatically launched by the Linux kernel when you try to
+launch x86 executables. It requires the @code{binfmt_misc} module in the
+Linux kernel.
-Very simple statically linked x86 program, just to test QEMU during a
-port to a new host CPU.
+@item The x86 version of QEMU is also included. You can try weird things such as:
+@example
+qemu-i386 /usr/local/qemu-i386/bin/qemu-i386 /usr/local/qemu-i386/bin/ls-i386
+@end example
-@section @file{test-i386}
+@end itemize
-This program executes most of the 16 bit and 32 bit x86 instructions and
-generates a text output. It can be compared with the output obtained with
-a real CPU or another emulator. The target @code{make test} runs this
-program and a @code{diff} on the generated output.
+@section Wine launch
-The Linux system call @code{modify_ldt()} is used to create x86 selectors
-to test some 16 bit addressing and 32 bit with segmentation cases.
+@itemize
-@section @file{testsig}
+@item Ensure that you have a working QEMU with the x86 glibc
+distribution (see previous section). In order to verify it, you must be
+able to do:
-This program tests various signal cases, including SIGFPE, SIGSEGV and
-SIGILL.
+@example
+qemu-i386 /usr/local/qemu-i386/bin/ls-i386
+@end example
+
+@item Download the binary x86 Wine install
+(@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page).
+
+@item Configure Wine on your account. Look at the provided script
+@file{/usr/local/qemu-i386/bin/wine-conf.sh}. Your previous
+@code{$@{HOME@}/.wine} directory is saved to @code{$@{HOME@}/.wine.org}.
+
+@item Then you can try the example @file{putty.exe}:
+
+@example
+qemu-i386 /usr/local/qemu-i386/wine/bin/wine /usr/local/qemu-i386/wine/c/Program\ Files/putty.exe
+@end example
-@section @file{testclone}
+@end itemize
-Tests the @code{clone()} system call (basic test).
+@section Command line options
-@section @file{testthread}
+@example
+usage: qemu-i386 [-h] [-d] [-L path] [-s size] program [arguments...]
+@end example
-Tests the glibc threads (more complicated than @code{clone()} because signals
-are also used).
+@table @option
+@item -h
+Print the help
+@item -L path
+Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)
+@item -s size
+Set the x86 stack size in bytes (default=524288)
+@end table
-@section @file{sha1}
+Debug options:
-It is a simple benchmark. Care must be taken to interpret the results
-because it mostly tests the ability of the virtual CPU to optimize the
-@code{rol} x86 instruction and the condition code computations.
+@table @option
+@item -d
+Activate log (logfile=/tmp/qemu.log)
+@item -p pagesize
+Act as if the host page size was 'pagesize' bytes
+@end table
projects / qemu / blobdiff