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revision 1.57 by bellard, Sat Feb 12 15:16:03 2005 UTC revision 1.58 by bellard, Sun Feb 20 19:09:44 2005 UTC
# Line 35  to ease cross-compilation and cross-debu Line 35  to ease cross-compilation and cross-debu
35  @end itemize  @end itemize
36    
37  QEMU can run without an host kernel driver and yet gives acceptable  QEMU can run without an host kernel driver and yet gives acceptable
38  performance. On an x86 host, if you want the highest performance for  performance.
 the x86 target, the @emph{QEMU Accelerator Module} (KQEMU) allows QEMU  
 to reach near native performances. KQEMU is currently only supported  
 for an x86 Linux 2.4 or 2.6 host system, but more host OSes will be  
 supported in the future.  
39    
40  For system emulation, the following hardware targets are supported:  For system emulation, the following hardware targets are supported:
41  @itemize  @itemize
# Line 343  translation mode (@var{t}=none, lba or a Line 339  translation mode (@var{t}=none, lba or a
339  all thoses parameters. This option is useful for old MS-DOS disk  all thoses parameters. This option is useful for old MS-DOS disk
340  images.  images.
341    
 @item -no-kqemu  
 Disable the usage of the QEMU Accelerator module (KQEMU). QEMU will work as  
 usual but will be slower. This option can be useful to determine if  
 emulation problems are coming from KQEMU.  
   
342  @item -isa  @item -isa
343  Simulate an ISA-only system (default is PCI system).  Simulate an ISA-only system (default is PCI system).
344  @item -std-vga  @item -std-vga
# Line 423  Fabrice Bellard Line 414  Fabrice Bellard
414    
415  @end ignore  @end ignore
416    
 @section QEMU Accelerator Module  
   
 The QEMU Accelerator Module (KQEMU) is an optional part of QEMU currently only  
 available for Linux 2.4 or 2.6 x86 hosts. It enables QEMU to run x86  
 code much faster. Provided it is installed on your PC (see  
 @ref{kqemu_install}), QEMU will automatically use it.  
   
 WARNING: as with any alpha stage kernel driver, KQEMU may cause  
 arbitrary data loss on your PC, so you'd better backup your sensitive  
 data before using it.  
   
 When using KQEMU, QEMU will create a big hidden file containing the  
 RAM of the virtual machine. For best performance, it is important that  
 this file is kept in RAM and not on the hard disk. QEMU uses the  
 @file{/dev/shm} directory to create this file because @code{tmpfs} is  
 usually mounted on it (check with the shell command  
 @code{df}). Otherwise @file{/tmp} is used as fallback. You can use the  
 @var{QEMU_TMPDIR} shell variable to set a new directory for the QEMU  
 RAM file.  
   
 KQEMU has only been tested with Linux 2.4, Linux 2.6 and Windows 2000  
 as guest OSes. If your guest OS do not work with KQEMU, you can  
 dynamically disable KQEMU with the @option{-no-kqemu} option.  
   
417  @section QEMU Monitor  @section QEMU Monitor
418    
419  The QEMU monitor is used to give complex commands to the QEMU  The QEMU monitor is used to give complex commands to the QEMU
# Line 1165  tar zxvf qemu-x.y.z.tar.gz Line 1132  tar zxvf qemu-x.y.z.tar.gz
1132  cd qemu-x.y.z  cd qemu-x.y.z
1133  @end example  @end example
1134    
 If you want to use the optional QEMU Accelerator Module, then download  
 it and install it in qemu-x.y.z/:  
 @example  
 tar zxvf /tmp/kqemu-x.y.z.tar.gz  
 @end example  
   
1135  Then you configure QEMU and build it (usually no options are needed):  Then you configure QEMU and build it (usually no options are needed):
1136  @example  @example
1137  ./configure  ./configure
# Line 1183  make install Line 1144  make install
1144  @end example  @end example
1145  to install QEMU in @file{/usr/local}.  to install QEMU in @file{/usr/local}.
1146    
 @node kqemu_install  
 @subsection QEMU Accelerator Installation  
   
 If you use x86 Linux, the compilation of the QEMU Accelerator Kernel  
 Module (KQEMU) is automatically activated provided you have the  
 necessary kernel headers. If nonetheless the compilation fails, you  
 can disable its compilation with the @option{--disable-kqemu} option.  
   
 If you are using a 2.6 host kernel, then all the necessary kernel  
 headers should be already installed. If you are using a 2.4 kernel,  
 then you should verify that properly configured kernel sources are  
 installed and compiled. On a Redhat 9 distribution for example, the  
 following must be done:  
 @example  
 1) Install the kernel-source-xxx package  
 2) cd /usr/src/linux-xxx  
 3) make distclean  
 4) Copy /boot/config-vvv in .config (use uname -r to know your configuration name 'vvv')  
 5) Edit the Makefile to change the EXTRAVERSION line to match your  
    current configuration name:  
    EXTRAVERSION = -custom  
 to  
    EXTRAVERSION = -8 # This is an example, it can be -8smp too  
 5) make menuconfig # Just save the configuration  
 6) make dep bzImage  
 @end example  
   
 The installation of KQEMU is not fully automatic because it is highly  
 distribution dependent. When launching  
 @example  
 make install  
 @end example  
   
 KQEMU is installed in /lib/modules/@var{kernel_version}/misc. The  
 device @file{/dev/kqemu} is created with read/write access rights for  
 everyone. If you fear security issues, you can restrict the access  
 rights of @file{/dev/kqemu}.  
   
 If you want that KQEMU is installed automatically at boot time, you can add  
   
 @example  
 # Load the KQEMU kernel module  
 /sbin/modprobe kqemu  
 @end example  
   
 in @file{/etc/rc.d/rc.local}.  
   
 If your distribution uses udev (like Fedora), the @file{/dev/kqemu} is  
 not created automatically (yet) at every reboot. You can add the  
 following in @file{/etc/rc.d/rc.local}:  
   
 @example  
 # Create the KQEMU device  
 mknod /dev/kqemu c 250 0  
 chmod 666 /dev/kqemu  
 @end example  
   
1147  @subsection Tested tool versions  @subsection Tested tool versions
1148    
1149  In order to compile QEMU succesfully, it is very important that you  In order to compile QEMU succesfully, it is very important that you

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