--- /dev/null
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/arch/i386/Kconfig .32324-linux-2.6.0.updated/arch/i386/Kconfig
+--- .32324-linux-2.6.0/arch/i386/Kconfig 2003-10-09 18:02:48.000000000 +1000
++++ .32324-linux-2.6.0.updated/arch/i386/Kconfig 2003-12-26 16:46:49.000000000 +1100
+@@ -307,6 +307,14 @@ config X86_GENERIC
+ when it has moderate overhead. This is intended for generic
+ distributions kernels.
+
++config QEMU
++ bool "Kernel to run under QEMU"
++ depends on EXPERIMENTAL
++ help
++ Select this if you want to boot the kernel inside qemu-fast,
++ the non-mmu version of the x86 emulator. See
++ <http://fabrice.bellard.free.fr/qemu/>. Say N.
++
+ #
+ # Define implied options from the CPU selection here
+ #
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/arch/i386/kernel/Makefile .32324-linux-2.6.0.updated/arch/i386/kernel/Makefile
+--- .32324-linux-2.6.0/arch/i386/kernel/Makefile 2003-09-29 10:25:15.000000000 +1000
++++ .32324-linux-2.6.0.updated/arch/i386/kernel/Makefile 2003-12-26 16:46:49.000000000 +1100
+@@ -46,12 +46,14 @@ quiet_cmd_syscall = SYSCALL $@
+ cmd_syscall = $(CC) -nostdlib $(SYSCFLAGS_$(@F)) \
+ -Wl,-T,$(filter-out FORCE,$^) -o $@
+
++export AFLAGS_vsyscall.lds.o += -P -C -U$(ARCH)
++
+ vsyscall-flags = -shared -s -Wl,-soname=linux-gate.so.1
+ SYSCFLAGS_vsyscall-sysenter.so = $(vsyscall-flags)
+ SYSCFLAGS_vsyscall-int80.so = $(vsyscall-flags)
+
+ $(obj)/vsyscall-int80.so $(obj)/vsyscall-sysenter.so: \
+-$(obj)/vsyscall-%.so: $(src)/vsyscall.lds $(obj)/vsyscall-%.o FORCE
++$(obj)/vsyscall-%.so: $(src)/vsyscall.lds.s $(obj)/vsyscall-%.o FORCE
+ $(call if_changed,syscall)
+
+ # We also create a special relocatable object that should mirror the symbol
+@@ -62,5 +64,5 @@ $(obj)/built-in.o: $(obj)/vsyscall-syms.
+ $(obj)/built-in.o: ld_flags += -R $(obj)/vsyscall-syms.o
+
+ SYSCFLAGS_vsyscall-syms.o = -r
+-$(obj)/vsyscall-syms.o: $(src)/vsyscall.lds $(obj)/vsyscall-sysenter.o FORCE
++$(obj)/vsyscall-syms.o: $(src)/vsyscall.lds.s $(obj)/vsyscall-sysenter.o FORCE
+ $(call if_changed,syscall)
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/arch/i386/kernel/vmlinux.lds.S .32324-linux-2.6.0.updated/arch/i386/kernel/vmlinux.lds.S
+--- .32324-linux-2.6.0/arch/i386/kernel/vmlinux.lds.S 2003-09-22 10:27:28.000000000 +1000
++++ .32324-linux-2.6.0.updated/arch/i386/kernel/vmlinux.lds.S 2003-12-26 16:46:49.000000000 +1100
+@@ -3,6 +3,7 @@
+ */
+
+ #include <asm-generic/vmlinux.lds.h>
++#include <asm/page.h>
+
+ OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+ OUTPUT_ARCH(i386)
+@@ -10,7 +11,7 @@ ENTRY(startup_32)
+ jiffies = jiffies_64;
+ SECTIONS
+ {
+- . = 0xC0000000 + 0x100000;
++ . = __PAGE_OFFSET + 0x100000;
+ /* read-only */
+ _text = .; /* Text and read-only data */
+ .text : {
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/arch/i386/kernel/vsyscall.lds .32324-linux-2.6.0.updated/arch/i386/kernel/vsyscall.lds
+--- .32324-linux-2.6.0/arch/i386/kernel/vsyscall.lds 2003-09-22 10:07:26.000000000 +1000
++++ .32324-linux-2.6.0.updated/arch/i386/kernel/vsyscall.lds 1970-01-01 10:00:00.000000000 +1000
+@@ -1,67 +0,0 @@
+-/*
+- * Linker script for vsyscall DSO. The vsyscall page is an ELF shared
+- * object prelinked to its virtual address, and with only one read-only
+- * segment (that fits in one page). This script controls its layout.
+- */
+-
+-/* This must match <asm/fixmap.h>. */
+-VSYSCALL_BASE = 0xffffe000;
+-
+-SECTIONS
+-{
+- . = VSYSCALL_BASE + SIZEOF_HEADERS;
+-
+- .hash : { *(.hash) } :text
+- .dynsym : { *(.dynsym) }
+- .dynstr : { *(.dynstr) }
+- .gnu.version : { *(.gnu.version) }
+- .gnu.version_d : { *(.gnu.version_d) }
+- .gnu.version_r : { *(.gnu.version_r) }
+-
+- /* This linker script is used both with -r and with -shared.
+- For the layouts to match, we need to skip more than enough
+- space for the dynamic symbol table et al. If this amount
+- is insufficient, ld -shared will barf. Just increase it here. */
+- . = VSYSCALL_BASE + 0x400;
+-
+- .text : { *(.text) } :text =0x90909090
+-
+- .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
+- .eh_frame : { KEEP (*(.eh_frame)) } :text
+- .dynamic : { *(.dynamic) } :text :dynamic
+- .useless : {
+- *(.got.plt) *(.got)
+- *(.data .data.* .gnu.linkonce.d.*)
+- *(.dynbss)
+- *(.bss .bss.* .gnu.linkonce.b.*)
+- } :text
+-}
+-
+-/*
+- * We must supply the ELF program headers explicitly to get just one
+- * PT_LOAD segment, and set the flags explicitly to make segments read-only.
+- */
+-PHDRS
+-{
+- text PT_LOAD FILEHDR PHDRS FLAGS(5); /* PF_R|PF_X */
+- dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
+- eh_frame_hdr 0x6474e550; /* PT_GNU_EH_FRAME, but ld doesn't match the name */
+-}
+-
+-/*
+- * This controls what symbols we export from the DSO.
+- */
+-VERSION
+-{
+- LINUX_2.5 {
+- global:
+- __kernel_vsyscall;
+- __kernel_sigreturn;
+- __kernel_rt_sigreturn;
+-
+- local: *;
+- };
+-}
+-
+-/* The ELF entry point can be used to set the AT_SYSINFO value. */
+-ENTRY(__kernel_vsyscall);
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/arch/i386/kernel/vsyscall.lds.S .32324-linux-2.6.0.updated/arch/i386/kernel/vsyscall.lds.S
+--- .32324-linux-2.6.0/arch/i386/kernel/vsyscall.lds.S 1970-01-01 10:00:00.000000000 +1000
++++ .32324-linux-2.6.0.updated/arch/i386/kernel/vsyscall.lds.S 2003-12-26 16:46:49.000000000 +1100
+@@ -0,0 +1,67 @@
++/*
++ * Linker script for vsyscall DSO. The vsyscall page is an ELF shared
++ * object prelinked to its virtual address, and with only one read-only
++ * segment (that fits in one page). This script controls its layout.
++ */
++#include <asm/fixmap.h>
++
++VSYSCALL_BASE = __FIXADDR_TOP - 0x1000;
++
++SECTIONS
++{
++ . = VSYSCALL_BASE + SIZEOF_HEADERS;
++
++ .hash : { *(.hash) } :text
++ .dynsym : { *(.dynsym) }
++ .dynstr : { *(.dynstr) }
++ .gnu.version : { *(.gnu.version) }
++ .gnu.version_d : { *(.gnu.version_d) }
++ .gnu.version_r : { *(.gnu.version_r) }
++
++ /* This linker script is used both with -r and with -shared.
++ For the layouts to match, we need to skip more than enough
++ space for the dynamic symbol table et al. If this amount
++ is insufficient, ld -shared will barf. Just increase it here. */
++ . = VSYSCALL_BASE + 0x400;
++
++ .text : { *(.text) } :text =0x90909090
++
++ .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
++ .eh_frame : { KEEP (*(.eh_frame)) } :text
++ .dynamic : { *(.dynamic) } :text :dynamic
++ .useless : {
++ *(.got.plt) *(.got)
++ *(.data .data.* .gnu.linkonce.d.*)
++ *(.dynbss)
++ *(.bss .bss.* .gnu.linkonce.b.*)
++ } :text
++}
++
++/*
++ * We must supply the ELF program headers explicitly to get just one
++ * PT_LOAD segment, and set the flags explicitly to make segments read-only.
++ */
++PHDRS
++{
++ text PT_LOAD FILEHDR PHDRS FLAGS(5); /* PF_R|PF_X */
++ dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
++ eh_frame_hdr 0x6474e550; /* PT_GNU_EH_FRAME, but ld doesn't match the name */
++}
++
++/*
++ * This controls what symbols we export from the DSO.
++ */
++VERSION
++{
++ LINUX_2.5 {
++ global:
++ __kernel_vsyscall;
++ __kernel_sigreturn;
++ __kernel_rt_sigreturn;
++
++ local: *;
++ };
++}
++
++/* The ELF entry point can be used to set the AT_SYSINFO value. */
++ENTRY(__kernel_vsyscall);
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/include/asm-i386/fixmap.h .32324-linux-2.6.0.updated/include/asm-i386/fixmap.h
+--- .32324-linux-2.6.0/include/asm-i386/fixmap.h 2003-09-22 10:09:12.000000000 +1000
++++ .32324-linux-2.6.0.updated/include/asm-i386/fixmap.h 2003-12-26 16:46:49.000000000 +1100
+@@ -14,6 +14,19 @@
+ #define _ASM_FIXMAP_H
+
+ #include <linux/config.h>
++
++/* used by vmalloc.c, vsyscall.lds.S.
++ *
++ * Leave one empty page between vmalloc'ed areas and
++ * the start of the fixmap.
++ */
++#ifdef CONFIG_QEMU
++#define __FIXADDR_TOP 0xa7fff000
++#else
++#define __FIXADDR_TOP 0xfffff000
++#endif
++
++#ifndef __ASSEMBLY__
+ #include <linux/kernel.h>
+ #include <asm/acpi.h>
+ #include <asm/apicdef.h>
+@@ -94,13 +107,8 @@ extern void __set_fixmap (enum fixed_add
+ #define clear_fixmap(idx) \
+ __set_fixmap(idx, 0, __pgprot(0))
+
+-/*
+- * used by vmalloc.c.
+- *
+- * Leave one empty page between vmalloc'ed areas and
+- * the start of the fixmap.
+- */
+-#define FIXADDR_TOP (0xfffff000UL)
++#define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
++
+ #define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
+ #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
+
+@@ -145,4 +153,5 @@ static inline unsigned long virt_to_fix(
+ return __virt_to_fix(vaddr);
+ }
+
++#endif /* !__ASSEMBLY__ */
+ #endif
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/include/asm-i386/page.h .32324-linux-2.6.0.updated/include/asm-i386/page.h
+--- .32324-linux-2.6.0/include/asm-i386/page.h 2003-09-22 10:06:42.000000000 +1000
++++ .32324-linux-2.6.0.updated/include/asm-i386/page.h 2003-12-26 16:46:49.000000000 +1100
+@@ -10,10 +10,10 @@
+ #define LARGE_PAGE_SIZE (1UL << PMD_SHIFT)
+
+ #ifdef __KERNEL__
+-#ifndef __ASSEMBLY__
+-
+ #include <linux/config.h>
+
++#ifndef __ASSEMBLY__
++
+ #ifdef CONFIG_X86_USE_3DNOW
+
+ #include <asm/mmx.h>
+@@ -115,12 +115,19 @@ static __inline__ int get_order(unsigned
+ #endif /* __ASSEMBLY__ */
+
+ #ifdef __ASSEMBLY__
++#ifdef CONFIG_QEMU
++#define __PAGE_OFFSET (0x90000000)
++#else
+ #define __PAGE_OFFSET (0xC0000000)
++#endif /* QEMU */
++#else
++#ifdef CONFIG_QEMU
++#define __PAGE_OFFSET (0x90000000UL)
+ #else
+ #define __PAGE_OFFSET (0xC0000000UL)
++#endif /* QEMU */
+ #endif
+
+-
+ #define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
+ #define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
+ #define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE)
+diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .32324-linux-2.6.0/include/asm-i386/param.h .32324-linux-2.6.0.updated/include/asm-i386/param.h
+--- .32324-linux-2.6.0/include/asm-i386/param.h 2003-09-21 17:26:06.000000000 +1000
++++ .32324-linux-2.6.0.updated/include/asm-i386/param.h 2003-12-26 16:46:49.000000000 +1100
+@@ -2,7 +2,12 @@
+ #define _ASMi386_PARAM_H
+
+ #ifdef __KERNEL__
+-# define HZ 1000 /* Internal kernel timer frequency */
++# include <linux/config.h>
++# ifdef CONFIG_QEMU
++# define HZ 100
++# else
++# define HZ 1000 /* Internal kernel timer frequency */
++# endif
+ # define USER_HZ 100 /* .. some user interfaces are in "ticks" */
+ # define CLOCKS_PER_SEC (USER_HZ) /* like times() */
+ #endif
\input texinfo @c -*- texinfo -*-
@iftex
-@settitle QEMU CPU Emulator Reference Documentation
+@settitle QEMU CPU Emulator User Documentation
@titlepage
@sp 7
-@center @titlefont{QEMU CPU Emulator Reference Documentation}
+@center @titlefont{QEMU CPU Emulator User Documentation}
@sp 3
@end titlepage
@end iftex
@section Features
-QEMU is a FAST! processor emulator. By using dynamic translation it
-achieves a reasonnable speed while being easy to port on new host
-CPUs.
+QEMU is a FAST! processor emulator using dynamic translation to
+achieve good emulation speed.
QEMU has two operating modes:
@itemize @minus
@item
-User mode emulation. In this mode, QEMU can launch Linux processes
-compiled for one CPU on another CPU. Linux system calls are converted
-because of endianness and 32/64 bit mismatches. The Wine Windows API
-emulator (@url{http://www.winehq.org}) and the DOSEMU DOS emulator
-(@url{http://www.dosemu.org}) are the main targets for QEMU.
+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
-Full system emulation. In this mode, QEMU emulates a full
-system, including a processor and various peripherials. Currently, it
-is only used to launch an x86 Linux kernel on an x86 Linux system. It
-enables easier testing and debugging of system code. It can also be
-used to provide virtual hosting of several virtual PCs on a single
-server.
+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.
@end itemize
-As QEMU requires no host kernel patches to run, it is very safe and
+As QEMU requires no host kernel driver to run, it is very safe and
easy to use.
-QEMU generic features:
+For system emulation, only the x86 PC emulator is currently
+usable. The PowerPC system emulator is being developped.
-@itemize
-
-@item User space only or full system emulation.
-
-@item Using dynamic translation to native code for reasonnable speed.
-
-@item Working on x86 and PowerPC hosts. Being tested on ARM, Sparc32, Alpha and S390.
-
-@item Self-modifying code support.
-
-@item Precise exceptions support.
-
-@item The virtual CPU is a library (@code{libqemu}) which can be used
-in other projects.
-
-@end itemize
-
-QEMU user mode emulation features:
-@itemize
-@item Generic Linux system call converter, including most ioctls.
-
-@item clone() emulation using native CPU clone() to use Linux scheduler for threads.
-
-@item Accurate signal handling by remapping host signals to target signals.
-@end itemize
-@end itemize
-
-QEMU full system emulation features:
-@itemize
-@item QEMU can either use a full software MMU for maximum portability or use the host system call mmap() to simulate the target MMU.
-@end itemize
-
-@section x86 emulation
-
-QEMU x86 target features:
-
-@itemize
-
-@item The virtual x86 CPU supports 16 bit and 32 bit addressing with segmentation.
-LDT/GDT and IDT are emulated. VM86 mode is also supported to run DOSEMU.
-
-@item Support of host page sizes bigger than 4KB in user mode emulation.
-
-@item QEMU can emulate itself on x86.
-
-@item An extensive Linux x86 CPU test program is included @file{tests/test-i386}.
-It can be used to test other x86 virtual CPUs.
-
-@end itemize
-
-Current QEMU limitations:
-
-@itemize
-
-@item No SSE/MMX support (yet).
-
-@item No x86-64 support.
-
-@item IPC syscalls are missing.
-
-@item The x86 segment limits and access rights are not tested at every
-memory access.
-
-@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 Some priviledged instructions or behaviors are missing, especially for segment protection testing (yet).
-
-@end itemize
-
-@section ARM emulation
-
-@itemize
-
-@item ARM emulation can currently launch small programs while using the
-generic dynamic code generation architecture of QEMU.
-
-@item No FPU support (yet).
-
-@item No automatic regression testing (yet).
-
-@end itemize
-
-@section SPARC emulation
-
-The SPARC emulation is currently in development.
+For user emulation, x86, PowerPC, ARM, and SPARC CPUs are supported.
@chapter Installation
+@section Linux
+
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
tar zxvf /tmp/qemu-XXX-i386.tar.gz
@end example
-@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.
-
+@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 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
+@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.
-Then you can launch the precompiled @file{ls} x86 executable:
-
-@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.
-
-@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
+@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
-@section Wine launch
+@section Cross compilation for Windows with Linux
@itemize
+@item
+Install the MinGW cross compilation tools available at
+@url{http://www.mingw.org/}.
-@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:
+@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
-qemu-i386 /usr/local/qemu-i386/bin/ls-i386
+./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 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
+@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
-@section Command line options
+Note: Currently, Wine does not seem able to launch
+QEMU for Win32.
-@example
-usage: qemu-i386 [-h] [-d] [-L path] [-s size] program [arguments...]
-@end example
+@section Mac OS X
-@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
-
-Debug options:
-
-@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
+Mac OS X is currently not supported.
@chapter QEMU System emulator invocation
@c man begin DESCRIPTION
-The QEMU System emulator simulates a complete PC. It can either boot
-directly a Linux kernel (without any BIOS or boot loader) or boot like a
-real PC with the included BIOS.
+The QEMU System emulator simulates a complete PC.
In order to meet specific user needs, two versions of QEMU are
available:
PS/2 mouse and keyboard
@item
2 IDE interfaces with hard disk and CD-ROM support
+@item
+Floppy disk
@item
-NE2000 network adapter (port=0x300, irq=9)
+up to 6 NE2000 network adapters
@item
Serial port
@item
Soundblaster 16 card
-@item
-PIC (interrupt controler)
-@item
-PIT (timers)
-@item
-CMOS memory
@end itemize
@c man end
Linux should boot and give you a prompt.
-@section Direct Linux Boot and Network emulation
-
-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.
-
-@enumerate
-@item
-Download the archive @file{linux-test-xxx.tar.gz} containing a Linux
-kernel and a disk image.
-
-@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.
-
-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
-
-Then enable X11 connections on your PC from the emulated Linux:
-@example
-xhost +172.20.0.2
-@end example
-
-You can now launch @file{xterm} or @file{xlogo} and verify that you have
-a real Virtual Linux system !
-
-@end enumerate
-
-NOTES:
-@enumerate
-@item
-A 2.5.74 kernel is also included in the archive. Just
-replace the bzImage in qemu.sh to try it.
-
-@item
-qemu 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.
-
-@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.
-
-@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
-
-@item
-The example disk image is a modified version of the one made by Kevin
-Lawton for the plex86 Project (@url{www.plex86.org}).
-
-@end enumerate
-
@section Invocation
@example
Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and and
@option{-cdrom} at the same time).
-@item -boot [a|b|c|d]
-Boot on floppy (a, b), hard disk (c) or CD-ROM (d). Hard disk boot is
+@item -boot [a|c|d]
+Boot on floppy (a), hard disk (c) or CD-ROM (d). Hard disk boot is
the default.
@item -snapshot
@item -m megs
Set virtual RAM size to @var{megs} megabytes.
-@item -n script
-Set 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 -initrd file
Use @var{file} as initial ram disk.
-@item -tun-fd fd
-Assumes @var{fd} talks to tap/tun and use it. Read
-@url{http://bellard.org/qemu/tetrinet.html} to have an example of its
-use.
-
@item -nographic
Normally, QEMU uses SDL to display the VGA output. With this option,
@end table
-Linux boot specific (does not require a full PC boot with a BIOS):
+Network options:
+
+@table @option
+
+@item -n script
+Set 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 nics n
+Simulate @var{n} network interfaces (default=1).
+
+@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 fd1,...
+Assumes @var{fd} talks to tap/tun and use it. Read
+@url{http://bellard.org/qemu/tetrinet.html} to have an example of its
+use.
+
+@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
Output log in /tmp/qemu.log
@end table
-During emulation, use @key{C-a h} to get terminal commands:
+During emulation, if you are using the serial console, use @key{C-a h}
+to get terminal commands:
@table @key
@item C-a h
@item C-a s
Save disk data back to file (if -snapshot)
@item C-a b
-Send break (magic sysrq)
+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
@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 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)
+
+@end table
+
+Examples:
+@itemize
+@item
+Dump 10 instructions at the current instruction pointer:
+@example
+(qemu) x/10i $eip
+0x90107063: ret
+0x90107064: sti
+0x90107065: lea 0x0(%esi,1),%esi
+0x90107069: lea 0x0(%edi,1),%edi
+0x90107070: ret
+0x90107071: jmp 0x90107080
+0x90107073: nop
+0x90107074: nop
+0x90107075: nop
+0x90107076: nop
+@end example
+
+@item
+Dump 80 16 bit values at the start of the video memory.
+@example
+(qemu) xp/80hx 0xb8000
+0x000b8000: 0x0b50 0x0b6c 0x0b65 0x0b78 0x0b38 0x0b36 0x0b2f 0x0b42
+0x000b8010: 0x0b6f 0x0b63 0x0b68 0x0b73 0x0b20 0x0b56 0x0b47 0x0b41
+0x000b8020: 0x0b42 0x0b69 0x0b6f 0x0b73 0x0b20 0x0b63 0x0b75 0x0b72
+0x000b8030: 0x0b72 0x0b65 0x0b6e 0x0b74 0x0b2d 0x0b63 0x0b76 0x0b73
+0x000b8040: 0x0b20 0x0b30 0x0b35 0x0b20 0x0b4e 0x0b6f 0x0b76 0x0b20
+0x000b8050: 0x0b32 0x0b30 0x0b30 0x0b33 0x0720 0x0720 0x0720 0x0720
+0x000b8060: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+0x000b8070: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+0x000b8080: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
+@end example
+@end itemize
+
+@item p or print/fmt expr
+
+Print expression value. Only the @var{format} part of @var{fmt} is
+used.
-@c man begin AUTHOR
-Fabrice Bellard
-@c man end
+@end table
-@end ignore
+@subsection Integer expressions
+
+The monitor understands integers expressions for every integer
+argument. You can use register names to get the value of specifics
+CPU registers by prefixing them with @emph{$}.
-@end ignore
@node disk_images
@section Disk Images
the real one. To know it, use the @code{ls -ls} command.
@end enumerate
+@section Direct Linux Boot and Network emulation
+
+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.
+
+@enumerate
+@item
+Download the archive @file{linux-test-xxx.tar.gz} containing a Linux
+kernel and a disk image.
+
+@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.
+
+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
+
+Then enable X11 connections on your PC from the emulated Linux:
+@example
+xhost +172.20.0.2
+@end example
+
+You can now launch @file{xterm} or @file{xlogo} and verify that you have
+a real Virtual Linux system !
+
+@end enumerate
+
+NOTES:
+@enumerate
+@item
+A 2.5.74 kernel is also included in the archive. Just
+replace the bzImage in qemu.sh to try it.
+
+@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.
+
+@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.
+
+@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
+
+@item
+The example disk image is a modified version of the one made by Kevin
+Lawton for the plex86 Project (@url{www.plex86.org}).
+
+@end enumerate
+
@node linux_compile
@section Linux Kernel Compilation
You can use any linux kernel with QEMU. However, if you want to use
-@code{qemu-fast} to get maximum performances, you should make the
-following changes to the Linux kernel (only 2.4.x and 2.5.x were
-tested):
+@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:
@enumerate
@item
use an SMP kernel with QEMU, it only supports one CPU.
@item
-If you are not using a 2.5 kernel as host kernel but if you use a target
-2.5 kernel, you must also ensure that the 'HZ' define is set to 100
+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 < 2.5. In
+frequencies greater than 100 Hz on host Linux systems < 2.6. In
@file{include/asm/param.h}, replace:
@example
@code{x/10i $cs*16+*eip} to dump the code at the PC position.
@end enumerate
-@chapter QEMU Internals
-
-@section QEMU compared to other emulators
-
-Like bochs [3], QEMU emulates an x86 CPU. But QEMU is much faster than
-bochs as it uses dynamic compilation and because it uses the host MMU to
-simulate the x86 MMU. The downside is that currently the emulation is
-not as accurate as bochs (for example, you cannot currently run Windows
-inside QEMU).
-
-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). The Valgrind dynamic translator generates better code
-than QEMU (in particular it does register allocation) but it is closely
-tied to an x86 host and target and has no support for precise exceptions
-and system emulation.
-
-EM86 [4] is the closest project to user space 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]).
-
-TWIN [6] is a Windows API emulator like Wine. It is less accurate than
-Wine but includes a protected mode x86 interpreter to launch x86 Windows
-executables. Such an approach as greater potential because most of the
-Windows API is executed natively but it is far more difficult to develop
-because all the data structures and function parameters exchanged
-between the API and the x86 code must be converted.
-
-User mode Linux [7] was the only solution before QEMU to launch a Linux
-kernel as a process while not needing any host kernel patches. However,
-user mode Linux requires heavy kernel patches while QEMU accepts
-unpatched Linux kernels. It would be interesting to compare the
-performance of the two approaches.
-
-The new Plex86 [8] PC virtualizer is done in the same spirit as the QEMU
-system emulator. It requires a patched Linux kernel to work (you cannot
-launch the same kernel on your PC), but the patches are really small. As
-it is a PC virtualizer (no emulation is done except for some priveledged
-instructions), it has the potential of being faster than QEMU. The
-downside is that a complicated (and potentially unsafe) host kernel
-patch is needed.
-
-@section Portable dynamic translation
-
-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 dependent. QEMU uses some tricks
-which make it relatively easily portable and simple while achieving good
-performances.
-
-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()}).
-
-In essence, the process is similar to [1], but more work is done at
-compile time.
-
-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.
-
-That way, QEMU is no more difficult to port than a dynamic linker.
-
-To go even faster, GCC static register variables are used to keep the
-state of the virtual CPU.
-
-@section Register allocation
-
-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.
-
-@section Condition code optimisations
-
-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 just stores one operand (called @code{CC_SRC}), the
-result (called @code{CC_DST}) and the type of operation (called
-@code{CC_OP}).
-
-@code{CC_OP} is almost never explicitely set in the generated code
-because it is known at translation time.
-
-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.
-
-@section CPU state optimisations
-
-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.
-
-[The FPU stack pointer register is not handled that way yet].
-
-@section Translation cache
-
-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).
-
-@section Direct block chaining
-
-After each translated basic block is executed, QEMU uses the simulated
-Program Counter (PC) and other cpu state informations (such as the CS
-segment base value) to find the next basic block.
-
-In order to accelerate the most common cases where the new simulated PC
-is known, QEMU can patch a basic block so that it jumps directly to the
-next one.
-
-The most portable code uses an indirect jump. An indirect jump makes it
-easier to make the jump target modification atomic. On some
-architectures (such as PowerPC), the @code{JUMP} opcode is directly
-patched so that the block chaining has no overhead.
-
-@section Self-modifying code and translated code invalidation
-
-Self-modifying code is a special challenge in x86 emulation because no
-instruction cache invalidation is signaled by the application when code
-is modified.
-
-When translated code is generated for a basic block, the corresponding
-host page is write protected if it is not already read-only (with the
-system call @code{mprotect()}). Then, if a write access is done to the
-page, Linux raises a SEGV signal. QEMU then invalidates all the
-translated code in the page and enables write accesses to the page.
-
-Correct translated code invalidation is done efficiently by maintaining
-a linked list of every translated block contained in a given page. Other
-linked lists are also maintained to undo direct block chaining.
-
-Although the overhead of doing @code{mprotect()} calls is important,
-most MSDOS programs can be emulated at reasonnable speed with QEMU and
-DOSEMU.
-
-Note that QEMU also invalidates pages of translated code when it detects
-that memory mappings are modified with @code{mmap()} or @code{munmap()}.
-
-@section Exception support
-
-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. The exact CPU state can be retrieved because all the
-x86 registers are stored in fixed host registers. The simulated program
-counter is found by retranslating the corresponding basic block and by
-looking where the host program counter was at the exception point.
-
-The virtual CPU cannot retrieve the exact @code{EFLAGS} register because
-in some cases it is not computed because of condition code
-optimisations. It is not a big concern because the emulated code can
-still be restarted in any cases.
-
-@section Linux system call translation
-
-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}).
+@chapter QEMU User space emulator invocation
-QEMU supports host CPUs which have pages bigger than 4KB. It records all
-the mappings the process does and try to emulated the @code{mmap()}
-system calls in cases where the host @code{mmap()} call would fail
-because of bad page alignment.
+@section Quick Start
-@section Linux signals
+In order to launch a Linux process, QEMU needs the process executable
+itself and all the target (x86) dynamic libraries used by it.
-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.
+@itemize
-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()}).
+@item On x86, you can just try to launch any process by using the native
+libraries:
-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}).
+@example
+qemu-i386 -L / /bin/ls
+@end example
-@section clone() system call and threads
+@code{-L /} tells that the x86 dynamic linker must be searched with a
+@file{/} prefix.
-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.
+@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):
-The virtual x86 CPU atomic operations are emulated with a global lock so
-that their semantic is preserved.
+@example
+qemu-i386 -L / qemu-i386 -L / /bin/ls
+@end example
-Note that currently there are still some locking issues in QEMU. In
-particular, the translated cache flush is not protected yet against
-reentrancy.
+@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:
-@section Self-virtualization
+@example
+unset LD_LIBRARY_PATH
+@end example
-QEMU was conceived so that ultimately it can emulate itself. Although
-it is not very useful, it is an important test to show the power of the
-emulator.
+Then you can launch the precompiled @file{ls} x86 executable:
-Achieving self-virtualization is not easy because there may be address
-space conflicts. QEMU solves this problem by being an executable ELF
-shared object as the ld-linux.so ELF interpreter. That way, it can be
-relocated at load time.
+@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.
-@section MMU emulation
+@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
-For system emulation, QEMU uses the mmap() system call to emulate the
-target CPU MMU. It works as long the emulated OS does not use an area
-reserved by the host OS (such as the area above 0xc0000000 on x86
-Linux).
+@end itemize
-It is planned to add a slower but more precise MMU emulation
-with a software MMU.
+@section Wine launch
-@section Bibliography
+@itemize
-@table @asis
+@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:
-@item [1]
-@url{http://citeseer.nj.nec.com/piumarta98optimizing.html}, Optimizing
-direct threaded code by selective inlining (1998) by Ian Piumarta, Fabio
-Riccardi.
+@example
+qemu-i386 /usr/local/qemu-i386/bin/ls-i386
+@end example
-@item [2]
-@url{http://developer.kde.org/~sewardj/}, Valgrind, an open-source
-memory debugger for x86-GNU/Linux, by Julian Seward.
+@item Download the binary x86 Wine install
+(@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page).
-@item [3]
-@url{http://bochs.sourceforge.net/}, the Bochs IA-32 Emulator Project,
-by Kevin Lawton et al.
+@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 [4]
-@url{http://www.cs.rose-hulman.edu/~donaldlf/em86/index.html}, the EM86
-x86 emulator on Alpha-Linux.
+@item Then you can try the example @file{putty.exe}:
-@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.
+@example
+qemu-i386 /usr/local/qemu-i386/wine/bin/wine /usr/local/qemu-i386/wine/c/Program\ Files/putty.exe
+@end example
-@item [6]
-@url{http://www.willows.com/}, Windows API library emulation from
-Willows Software.
+@end itemize
-@item [7]
-@url{http://user-mode-linux.sourceforge.net/},
-The User-mode Linux Kernel.
+@section Command line options
-@item [8]
-@url{http://www.plex86.org/},
-The new Plex86 project.
+@example
+usage: qemu-i386 [-h] [-d] [-L path] [-s size] program [arguments...]
+@end example
+@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
-@chapter Regression Tests
-
-In the directory @file{tests/}, various interesting testing programs
-are available. There are used for regression testing.
-
-@section @file{test-i386}
-
-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.
-
-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.
-
-The Linux system call @code{vm86()} is used to test vm86 emulation.
-
-Various exceptions are raised to test most of the x86 user space
-exception reporting.
-
-@section @file{linux-test}
-
-This program tests various Linux system calls. It is used to verify
-that the system call parameters are correctly converted between target
-and host CPUs.
-
-@section @file{hello-i386}
-
-Very simple statically linked x86 program, just to test QEMU during a
-port to a new host CPU.
-
-@section @file{hello-arm}
-
-Very simple statically linked ARM program, just to test QEMU during a
-port to a new host CPU.
-
-@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
--- /dev/null
+\input texinfo @c -*- texinfo -*-
+
+@iftex
+@settitle QEMU Internals
+@titlepage
+@sp 7
+@center @titlefont{QEMU Internals}
+@sp 3
+@end titlepage
+@end iftex
+
+@chapter Introduction
+
+@section Features
+
+QEMU is a FAST! processor emulator using a portable dynamic
+translator.
+
+QEMU has two operating modes:
+
+@itemize @minus
+
+@item
+Full system emulation. In this mode, QEMU emulates a full system
+(usually a PC), including a processor and various peripherials. It can
+be used to launch an different Operating System without rebooting the
+PC or to debug system code.
+
+@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.
+
+@end itemize
+
+As QEMU requires no host kernel driver to run, it is very safe and
+easy to use.
+
+QEMU generic features:
+
+@itemize
+
+@item User space only or full system emulation.
+
+@item Using dynamic translation to native code for reasonnable speed.
+
+@item Working on x86 and PowerPC hosts. Being tested on ARM, Sparc32, Alpha and S390.
+
+@item Self-modifying code support.
+
+@item Precise exceptions support.
+
+@item The virtual CPU is a library (@code{libqemu}) which can be used
+in other projects.
+
+@end itemize
+
+QEMU user mode emulation features:
+@itemize
+@item Generic Linux system call converter, including most ioctls.
+
+@item clone() emulation using native CPU clone() to use Linux scheduler for threads.
+
+@item Accurate signal handling by remapping host signals to target signals.
+@end itemize
+@end itemize
+
+QEMU full system emulation features:
+@itemize
+@item QEMU can either use a full software MMU for maximum portability or use the host system call mmap() to simulate the target MMU.
+@end itemize
+
+@section x86 emulation
+
+QEMU x86 target features:
+
+@itemize
+
+@item The virtual x86 CPU supports 16 bit and 32 bit addressing with segmentation.
+LDT/GDT and IDT are emulated. VM86 mode is also supported to run DOSEMU.
+
+@item Support of host page sizes bigger than 4KB in user mode emulation.
+
+@item QEMU can emulate itself on x86.
+
+@item An extensive Linux x86 CPU test program is included @file{tests/test-i386}.
+It can be used to test other x86 virtual CPUs.
+
+@end itemize
+
+Current QEMU limitations:
+
+@itemize
+
+@item No SSE/MMX support (yet).
+
+@item No x86-64 support.
+
+@item IPC syscalls are missing.
+
+@item The x86 segment limits and access rights are not tested at every
+memory access (yet). Hopefully, very few OSes seem to rely on that for
+normal use.
+
+@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.
+
+@end itemize
+
+@section ARM emulation
+
+@itemize
+
+@item Full ARM 7 user emulation.
+
+@item NWFPE FPU support included in user Linux emulation.
+
+@item Can run most ARM Linux binaries.
+
+@end itemize
+
+@section PowerPC emulation
+
+@itemize
+
+@item Full PowerPC 32 bit emulation, including priviledged instructions,
+FPU and MMU.
+
+@item Can run most PowerPC Linux binaries.
+
+@end itemize
+
+@section SPARC emulation
+
+@itemize
+
+@item SPARC V8 user support, except FPU instructions.
+
+@item Can run some SPARC Linux binaries.
+
+@end itemize
+
+@chapter QEMU Internals
+
+@section QEMU compared to other emulators
+
+Like bochs [3], QEMU emulates an x86 CPU. But QEMU is much faster than
+bochs as it uses dynamic compilation. Bochs is closely tied to x86 PC
+emulation while QEMU can emulate several processors.
+
+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). The Valgrind dynamic translator generates better code
+than QEMU (in particular it does register allocation) but it is closely
+tied to an x86 host and target and has no support for precise exceptions
+and system emulation.
+
+EM86 [4] is the closest project to user space 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]).
+
+TWIN [6] is a Windows API emulator like Wine. It is less accurate than
+Wine but includes a protected mode x86 interpreter to launch x86 Windows
+executables. Such an approach as greater potential because most of the
+Windows API is executed natively but it is far more difficult to develop
+because all the data structures and function parameters exchanged
+between the API and the x86 code must be converted.
+
+User mode Linux [7] was the only solution before QEMU to launch a
+Linux kernel as a process while not needing any host kernel
+patches. However, user mode Linux requires heavy kernel patches while
+QEMU accepts unpatched Linux kernels. The price to pay is that QEMU is
+slower.
+
+The new Plex86 [8] PC virtualizer is done in the same spirit as the
+qemu-fast system emulator. It requires a patched Linux kernel to work
+(you cannot launch the same kernel on your PC), but the patches are
+really small. As it is a PC virtualizer (no emulation is done except
+for some priveledged instructions), it has the potential of being
+faster than QEMU. The downside is that a complicated (and potentially
+unsafe) host kernel patch is needed.
+
+The commercial PC Virtualizers (VMWare [9], VirtualPC [10], TwoOStwo
+[11]) are faster than QEMU, but they all need specific, proprietary
+and potentially unsafe host drivers. Moreover, they are unable to
+provide cycle exact simulation as an emulator can.
+
+@section Portable dynamic translation
+
+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 dependent. QEMU uses some tricks
+which make it relatively easily portable and simple while achieving good
+performances.
+
+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{target-i386/op.c}). Then a compile time tool
+(@file{dyngen}) takes the corresponding object file (@file{op.o})
+to generate a dynamic code generator which concatenates the simple
+instructions to build a function (see @file{op.h:dyngen_code()}).
+
+In essence, the process is similar to [1], but more work is done at
+compile time.
+
+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.
+
+That way, QEMU is no more difficult to port than a dynamic linker.
+
+To go even faster, GCC static register variables are used to keep the
+state of the virtual CPU.
+
+@section Register allocation
+
+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.
+
+@section Condition code optimisations
+
+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 just stores one operand (called @code{CC_SRC}), the
+result (called @code{CC_DST}) and the type of operation (called
+@code{CC_OP}).
+
+@code{CC_OP} is almost never explicitely set in the generated code
+because it is known at translation time.
+
+In order to increase performances, a backward pass is performed on the
+generated simple instructions (see
+@code{target-i386/translate.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.
+
+@section CPU state optimisations
+
+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.
+
+[The FPU stack pointer register is not handled that way yet].
+
+@section Translation cache
+
+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).
+
+@section Direct block chaining
+
+After each translated basic block is executed, QEMU uses the simulated
+Program Counter (PC) and other cpu state informations (such as the CS
+segment base value) to find the next basic block.
+
+In order to accelerate the most common cases where the new simulated PC
+is known, QEMU can patch a basic block so that it jumps directly to the
+next one.
+
+The most portable code uses an indirect jump. An indirect jump makes
+it easier to make the jump target modification atomic. On some host
+architectures (such as x86 or PowerPC), the @code{JUMP} opcode is
+directly patched so that the block chaining has no overhead.
+
+@section Self-modifying code and translated code invalidation
+
+Self-modifying code is a special challenge in x86 emulation because no
+instruction cache invalidation is signaled by the application when code
+is modified.
+
+When translated code is generated for a basic block, the corresponding
+host page is write protected if it is not already read-only (with the
+system call @code{mprotect()}). Then, if a write access is done to the
+page, Linux raises a SEGV signal. QEMU then invalidates all the
+translated code in the page and enables write accesses to the page.
+
+Correct translated code invalidation is done efficiently by maintaining
+a linked list of every translated block contained in a given page. Other
+linked lists are also maintained to undo direct block chaining.
+
+Although the overhead of doing @code{mprotect()} calls is important,
+most MSDOS programs can be emulated at reasonnable speed with QEMU and
+DOSEMU.
+
+Note that QEMU also invalidates pages of translated code when it detects
+that memory mappings are modified with @code{mmap()} or @code{munmap()}.
+
+When using a software MMU, the code invalidation is more efficient: if
+a given code page is invalidated too often because of write accesses,
+then a bitmap representing all the code inside the page is
+built. Every store into that page checks the bitmap to see if the code
+really needs to be invalidated. It avoids invalidating the code when
+only data is modified in the page.
+
+@section Exception support
+
+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. The exact CPU state can be retrieved because all the
+x86 registers are stored in fixed host registers. The simulated program
+counter is found by retranslating the corresponding basic block and by
+looking where the host program counter was at the exception point.
+
+The virtual CPU cannot retrieve the exact @code{EFLAGS} register because
+in some cases it is not computed because of condition code
+optimisations. It is not a big concern because the emulated code can
+still be restarted in any cases.
+
+@section MMU emulation
+
+For system emulation, QEMU uses the mmap() system call to emulate the
+target CPU MMU. It works as long the emulated OS does not use an area
+reserved by the host OS (such as the area above 0xc0000000 on x86
+Linux).
+
+In order to be able to launch any OS, QEMU also supports a soft
+MMU. In that mode, the MMU virtual to physical address translation is
+done at every memory access. QEMU uses an address translation cache to
+speed up the translation.
+
+In order to avoid flushing the translated code each time the MMU
+mappings change, QEMU uses a physically indexed translation cache. It
+means that each basic block is indexed with its physical address.
+
+When MMU mappings change, only the chaining of the basic blocks is
+reset (i.e. a basic block can no longer jump directly to another one).
+
+@section Hardware interrupts
+
+In order to be faster, QEMU does not check at every basic block if an
+hardware interrupt is pending. Instead, the user must asynchrously
+call a specific function to tell that an interrupt is pending. This
+function resets the chaining of the currently executing basic
+block. It ensures that the execution will return soon in the main loop
+of the CPU emulator. Then the main loop can test if the interrupt is
+pending and handle it.
+
+@section User emulation specific details
+
+@subsection Linux system call translation
+
+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}).
+
+QEMU supports host CPUs which have pages bigger than 4KB. It records all
+the mappings the process does and try to emulated the @code{mmap()}
+system calls in cases where the host @code{mmap()} call would fail
+because of bad page alignment.
+
+@subsection Linux signals
+
+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.
+
+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()}).
+
+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}).
+
+@subsection clone() system call and threads
+
+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.
+
+The virtual x86 CPU atomic operations are emulated with a global lock so
+that their semantic is preserved.
+
+Note that currently there are still some locking issues in QEMU. In
+particular, the translated cache flush is not protected yet against
+reentrancy.
+
+@subsection Self-virtualization
+
+QEMU was conceived so that ultimately it can emulate itself. Although
+it is not very useful, it is an important test to show the power of the
+emulator.
+
+Achieving self-virtualization is not easy because there may be address
+space conflicts. QEMU solves this problem by being an executable ELF
+shared object as the ld-linux.so ELF interpreter. That way, it can be
+relocated at load time.
+
+@section Bibliography
+
+@table @asis
+
+@item [1]
+@url{http://citeseer.nj.nec.com/piumarta98optimizing.html}, Optimizing
+direct threaded code by selective inlining (1998) by Ian Piumarta, Fabio
+Riccardi.
+
+@item [2]
+@url{http://developer.kde.org/~sewardj/}, Valgrind, an open-source
+memory debugger for x86-GNU/Linux, by Julian Seward.
+
+@item [3]
+@url{http://bochs.sourceforge.net/}, the Bochs IA-32 Emulator Project,
+by Kevin Lawton et al.
+
+@item [4]
+@url{http://www.cs.rose-hulman.edu/~donaldlf/em86/index.html}, the EM86
+x86 emulator on Alpha-Linux.
+
+@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.
+
+@item [6]
+@url{http://www.willows.com/}, Windows API library emulation from
+Willows Software.
+
+@item [7]
+@url{http://user-mode-linux.sourceforge.net/},
+The User-mode Linux Kernel.
+
+@item [8]
+@url{http://www.plex86.org/},
+The new Plex86 project.
+
+@item [9]
+@url{http://www.vmware.com/},
+The VMWare PC virtualizer.
+
+@item [10]
+@url{http://www.microsoft.com/windowsxp/virtualpc/},
+The VirtualPC PC virtualizer.
+
+@item [11]
+@url{http://www.twoostwo.org/},
+The TwoOStwo PC virtualizer.
+
+@end table
+
+@chapter Regression Tests
+
+In the directory @file{tests/}, various interesting testing programs
+are available. There are used for regression testing.
+
+@section @file{test-i386}
+
+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.
+
+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.
+
+The Linux system call @code{vm86()} is used to test vm86 emulation.
+
+Various exceptions are raised to test most of the x86 user space
+exception reporting.
+
+@section @file{linux-test}
+
+This program tests various Linux system calls. It is used to verify
+that the system call parameters are correctly converted between target
+and host CPUs.
+
+@section @file{hello-i386}
+
+Very simple statically linked x86 program, just to test QEMU during a
+port to a new host CPU.
+
+@section @file{hello-arm}
+
+Very simple statically linked ARM program, just to test QEMU during a
+port to a new host CPU.
+
+@section @file{sha1}
+
+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.
+
projects / qemu / commitdiff