1 \input texinfo @c -*- texinfo -*-
4 @settitle QEMU CPU Emulator User Documentation
7 @center @titlefont{QEMU CPU Emulator User Documentation}
16 QEMU is a FAST! processor emulator using dynamic translation to
17 achieve good emulation speed.
19 QEMU has two operating modes:
24 Full system emulation. In this mode, QEMU emulates a full system (for
25 example a PC), including a processor and various peripherials. It can
26 be used to launch different Operating Systems without rebooting the
27 PC or to debug system code.
30 User mode emulation (Linux host only). In this mode, QEMU can launch
31 Linux processes compiled for one CPU on another CPU. It can be used to
32 launch the Wine Windows API emulator (@url{http://www.winehq.org}) or
33 to ease cross-compilation and cross-debugging.
37 As QEMU requires no host kernel driver to run, it is very safe and
40 For system emulation, the following hardware targets are supported:
42 @item PC (x86 processor)
43 @item PREP (PowerPC processor)
44 @item PowerMac (PowerPC processor, in progress)
47 For user emulation, x86, PowerPC, ARM, and SPARC CPUs are supported.
51 If you want to compile QEMU yourself, see @ref{compilation}.
55 Download the binary distribution (@file{qemu-XXX-i386.tar.gz}) and
56 untar it as root in @file{/}:
61 tar zxvf /tmp/qemu-XXX-i386.tar.gz
66 Download the experimental binary installer at
67 @url{http://www.freeoszoo.org/download.php}.
71 Download the experimental binary installer at
72 @url{http://www.freeoszoo.org/download.php}.
74 @chapter QEMU PC System emulator invocation
78 @c man begin DESCRIPTION
80 The QEMU System emulator simulates a complete PC.
82 In order to meet specific user needs, two versions of QEMU are
88 @code{qemu-fast} uses the host Memory Management Unit (MMU) to
89 simulate the x86 MMU. It is @emph{fast} but has limitations because
90 the whole 4 GB address space cannot be used and some memory mapped
91 peripherials cannot be emulated accurately yet. Therefore, a specific
92 guest Linux kernel can be used (@xref{linux_compile}) as guest
95 Moreover there is no separation between the host and target address
96 spaces, so it offers no security (the target OS can modify the
97 @code{qemu-fast} code by writing at the right addresses).
100 @code{qemu} uses a software MMU. It is about @emph{two times slower}
101 but gives a more accurate emulation and a complete separation between
102 the host and target address spaces.
106 QEMU emulates the following PC peripherials:
110 i440FX host PCI bridge and PIIX3 PCI to ISA bridge
112 Cirrus CLGD 5446 PCI VGA card or dummy VGA card with Bochs VESA
113 extensions (hardware level, including all non standard modes).
115 PS/2 mouse and keyboard
117 2 PCI IDE interfaces with hard disk and CD-ROM support
121 NE2000 PCI network adapters
128 QEMU uses the PC BIOS from the Bochs project and the Plex86/Bochs LGPL
135 Download and uncompress the linux image (@file{linux.img}) and type:
141 Linux should boot and give you a prompt.
146 @c man begin SYNOPSIS
147 usage: qemu [options] [disk_image]
152 @var{disk_image} is a raw hard disk image for IDE hard disk 0.
158 Use @var{file} as floppy disk 0/1 image (@xref{disk_images}). You can
159 use the host floppy by using @file{/dev/fd0} as filename.
165 Use @var{file} as hard disk 0, 1, 2 or 3 image (@xref{disk_images}).
168 Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and and
169 @option{-cdrom} at the same time). You can use the host CD-ROM by
170 using @file{/dev/cdrom} as filename.
173 Boot on floppy (a), hard disk (c) or CD-ROM (d). Hard disk boot is
177 Write to temporary files instead of disk image files. In this case,
178 the raw disk image you use is not written back. You can however force
179 the write back by pressing @key{C-a s} (@xref{disk_images}).
182 Set virtual RAM size to @var{megs} megabytes. Default is 128 MB.
186 Normally, QEMU uses SDL to display the VGA output. With this option,
187 you can totally disable graphical output so that QEMU is a simple
188 command line application. The emulated serial port is redirected on
189 the console. Therefore, you can still use QEMU to debug a Linux kernel
190 with a serial console.
194 The SB16 emulation is disabled by default as it may give problems with
195 Windows. You can enable it manually with this option.
198 Set the real time clock to local time (the default is to UTC
199 time). This option is needed to have correct date in MS-DOS or
203 Start in full screen.
212 Set TUN/TAP network init script [default=/etc/qemu-ifup]. This script
213 is launched to configure the host network interface (usually tun0)
214 corresponding to the virtual NE2000 card.
218 Set the mac address of the first interface (the format is
219 aa:bb:cc:dd:ee:ff in hexa). The mac address is incremented for each
220 new network interface.
223 Assumes @var{fd} talks to a tap/tun host network interface and use
224 it. Read @url{http://bellard.org/qemu/tetrinet.html} to have an
228 Use the user mode network stack. This is the default if no tun/tap
229 network init script is found.
232 When using the user mode network stack, activate a built-in TFTP
233 server. All filenames beginning with @var{prefix} can be downloaded
234 from the host to the guest using a TFTP client. The TFTP client on the
235 guest must be configured in binary mode (use the command @code{bin} of
236 the Unix TFTP client). The host IP address on the guest is as usual
240 When using the user mode network stack, activate a built-in SMB
241 server so that Windows OSes can access to the host files in @file{dir}
244 In the guest Windows OS, the line:
248 must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
249 or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
251 Then @file{dir} can be accessed in @file{\\smbserver\qemu}.
253 Note that a SAMBA server must be installed on the host OS in
254 @file{/usr/sbin/smbd}. QEMU was tested succesfully with smbd version
255 2.2.7a from the Red Hat 9.
257 @item -redir [tcp|udp]:host-port:[guest-host]:guest-port
259 When using the user mode network stack, redirect incoming TCP or UDP
260 connections to the host port @var{host-port} to the guest
261 @var{guest-host} on guest port @var{guest-port}. If @var{guest-host}
262 is not specified, its value is 10.0.2.15 (default address given by the
263 built-in DHCP server).
265 For example, to redirect host X11 connection from screen 1 to guest
266 screen 0, use the following:
270 qemu -redir tcp:6001::6000 [...]
271 # this host xterm should open in the guest X11 server
275 To redirect telnet connections from host port 5555 to telnet port on
276 the guest, use the following:
280 qemu -redir tcp:5555::23 [...]
281 telnet localhost 5555
284 Then when you use on the host @code{telnet localhost 5555}, you
285 connect to the guest telnet server.
288 Use the dummy network stack: no packet will be received by the network
293 Linux boot specific. When using this options, you can use a given
294 Linux kernel without installing it in the disk image. It can be useful
295 for easier testing of various kernels.
299 @item -kernel bzImage
300 Use @var{bzImage} as kernel image.
302 @item -append cmdline
303 Use @var{cmdline} as kernel command line
306 Use @var{file} as initial ram disk.
310 Debug/Expert options:
314 Redirect the virtual serial port to host device @var{dev}. Available
320 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
324 [Unix only] standard input/output
326 The default device is @code{vc} in graphical mode and @code{stdio} in
329 This option can be used several times to simulate up to 4 serials
333 Redirect the monitor to host device @var{dev} (same devices as the
335 The default device is @code{vc} in graphical mode and @code{stdio} in
339 Wait gdb connection to port 1234 (@xref{gdb_usage}).
341 Change gdb connection port.
343 Do not start CPU at startup (you must type 'c' in the monitor).
345 Output log in /tmp/qemu.log
347 Simulate an ISA-only system (default is PCI system).
349 Simulate a standard VGA card with Bochs VBE extensions (default is
350 Cirrus Logic GD5446 PCI VGA)
352 Start right away with a saved state (@code{loadvm} in monitor)
361 During the graphical emulation, you can use the following keys:
367 Switch to virtual console 'n'. Standard console mappings are:
370 Target system display
378 Toggle mouse and keyboard grab.
381 In the virtual consoles, you can use @key{Ctrl-Up}, @key{Ctrl-Down},
382 @key{Ctrl-PageUp} and @key{Ctrl-PageDown} to move in the back log.
384 During emulation, if you are using the @option{-nographic} option, use
385 @key{Ctrl-a h} to get terminal commands:
393 Save disk data back to file (if -snapshot)
395 Send break (magic sysrq in Linux)
397 Switch between console and monitor
406 @settitle QEMU System Emulator
409 The HTML documentation of QEMU for more precise information and Linux
410 user mode emulator invocation.
422 @section QEMU Monitor
424 The QEMU monitor is used to give complex commands to the QEMU
425 emulator. You can use it to:
430 Remove or insert removable medias images
431 (such as CD-ROM or floppies)
434 Freeze/unfreeze the Virtual Machine (VM) and save or restore its state
437 @item Inspect the VM state without an external debugger.
443 The following commands are available:
447 @item help or ? [cmd]
448 Show the help for all commands or just for command @var{cmd}.
451 Commit changes to the disk images (if -snapshot is used)
453 @item info subcommand
454 show various information about the system state
458 show the network state
460 show the block devices
462 show the cpu registers
464 show the command line history
470 @item eject [-f] device
471 Eject a removable media (use -f to force it).
473 @item change device filename
474 Change a removable media.
476 @item screendump filename
477 Save screen into PPM image @var{filename}.
479 @item log item1[,...]
480 Activate logging of the specified items to @file{/tmp/qemu.log}.
482 @item savevm filename
483 Save the whole virtual machine state to @var{filename}.
485 @item loadvm filename
486 Restore the whole virtual machine state from @var{filename}.
494 @item gdbserver [port]
495 Start gdbserver session (default port=1234)
498 Virtual memory dump starting at @var{addr}.
501 Physical memory dump starting at @var{addr}.
503 @var{fmt} is a format which tells the command how to format the
504 data. Its syntax is: @option{/@{count@}@{format@}@{size@}}
508 is the number of items to be dumped.
511 can be x (hexa), d (signed decimal), u (unsigned decimal), o (octal),
512 c (char) or i (asm instruction).
515 can be b (8 bits), h (16 bits), w (32 bits) or g (64 bits). On x86,
516 @code{h} or @code{w} can be specified with the @code{i} format to
517 respectively select 16 or 32 bit code instruction size.
524 Dump 10 instructions at the current instruction pointer:
529 0x90107065: lea 0x0(%esi,1),%esi
530 0x90107069: lea 0x0(%edi,1),%edi
532 0x90107071: jmp 0x90107080
540 Dump 80 16 bit values at the start of the video memory.
542 (qemu) xp/80hx 0xb8000
543 0x000b8000: 0x0b50 0x0b6c 0x0b65 0x0b78 0x0b38 0x0b36 0x0b2f 0x0b42
544 0x000b8010: 0x0b6f 0x0b63 0x0b68 0x0b73 0x0b20 0x0b56 0x0b47 0x0b41
545 0x000b8020: 0x0b42 0x0b69 0x0b6f 0x0b73 0x0b20 0x0b63 0x0b75 0x0b72
546 0x000b8030: 0x0b72 0x0b65 0x0b6e 0x0b74 0x0b2d 0x0b63 0x0b76 0x0b73
547 0x000b8040: 0x0b20 0x0b30 0x0b35 0x0b20 0x0b4e 0x0b6f 0x0b76 0x0b20
548 0x000b8050: 0x0b32 0x0b30 0x0b30 0x0b33 0x0720 0x0720 0x0720 0x0720
549 0x000b8060: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
550 0x000b8070: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
551 0x000b8080: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
552 0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
556 @item p or print/fmt expr
558 Print expression value. Only the @var{format} part of @var{fmt} is
563 Send @var{keys} to the emulator. Use @code{-} to press several keys
564 simultaneously. Example:
569 This command is useful to send keys that your graphical user interface
570 intercepts at low level, such as @code{ctrl-alt-f1} in X Window.
578 @subsection Integer expressions
580 The monitor understands integers expressions for every integer
581 argument. You can use register names to get the value of specifics
582 CPU registers by prefixing them with @emph{$}.
587 @subsection Raw disk images
589 The disk images can simply be raw images of the hard disk. You can
590 create them with the command:
592 dd of=myimage bs=1024 seek=mysize count=0
594 where @var{myimage} is the image filename and @var{mysize} is its size
597 @subsection Snapshot mode
599 If you use the option @option{-snapshot}, all disk images are
600 considered as read only. When sectors in written, they are written in
601 a temporary file created in @file{/tmp}. You can however force the
602 write back to the raw disk images by pressing @key{C-a s}.
604 NOTE: The snapshot mode only works with raw disk images.
606 @subsection Copy On Write disk images
608 QEMU also supports user mode Linux
609 (@url{http://user-mode-linux.sourceforge.net/}) Copy On Write (COW)
610 disk images. The COW disk images are much smaller than normal images
611 as they store only modified sectors. They also permit the use of the
612 same disk image template for many users.
614 To create a COW disk images, use the command:
617 qemu-mkcow -f myrawimage.bin mycowimage.cow
620 @file{myrawimage.bin} is a raw image you want to use as original disk
621 image. It will never be written to.
623 @file{mycowimage.cow} is the COW disk image which is created by
624 @code{qemu-mkcow}. You can use it directly with the @option{-hdx}
625 options. You must not modify the original raw disk image if you use
626 COW images, as COW images only store the modified sectors from the raw
627 disk image. QEMU stores the original raw disk image name and its
628 modified time in the COW disk image so that chances of mistakes are
631 If the raw disk image is not read-only, by pressing @key{C-a s} you
632 can flush the COW disk image back into the raw disk image, as in
635 COW disk images can also be created without a corresponding raw disk
636 image. It is useful to have a big initial virtual disk image without
637 using much disk space. Use:
640 qemu-mkcow mycowimage.cow 1024
643 to create a 1 gigabyte empty COW disk image.
648 COW disk images must be created on file systems supporting
649 @emph{holes} such as ext2 or ext3.
651 Since holes are used, the displayed size of the COW disk image is not
652 the real one. To know it, use the @code{ls -ls} command.
655 @subsection Convert VMware disk images to raw disk images
657 You can use the tool @file{vmdk2raw} to convert VMware disk images to
658 raw disk images directly usable by QEMU. The syntax is:
660 vmdk2raw vmware_image output_image
663 @section Network emulation
665 QEMU simulates up to 6 networks cards (NE2000 boards). Each card can
666 be connected to a specific host network interface.
668 @subsection Using tun/tap network interface
670 This is the standard way to emulate network. QEMU adds a virtual
671 network device on your host (called @code{tun0}), and you can then
672 configure it as if it was a real ethernet card.
674 As an example, you can download the @file{linux-test-xxx.tar.gz}
675 archive and copy the script @file{qemu-ifup} in @file{/etc} and
676 configure properly @code{sudo} so that the command @code{ifconfig}
677 contained in @file{qemu-ifup} can be executed as root. You must verify
678 that your host kernel supports the TUN/TAP network interfaces: the
679 device @file{/dev/net/tun} must be present.
681 See @ref{direct_linux_boot} to have an example of network use with a
684 @subsection Using the user mode network stack
686 By using the option @option{-user-net} or if you have no tun/tap init
687 script, QEMU uses a completely user mode network stack (you don't need
688 root priviledge to use the virtual network). The virtual network
689 configuration is the following:
693 QEMU Virtual Machine <------> Firewall/DHCP server <-----> Internet
694 (10.0.2.x) | (10.0.2.2)
696 ----> DNS server (10.0.2.3)
698 ----> SMB server (10.0.2.4)
701 The QEMU VM behaves as if it was behind a firewall which blocks all
702 incoming connections. You can use a DHCP client to automatically
703 configure the network in the QEMU VM.
705 In order to check that the user mode network is working, you can ping
706 the address 10.0.2.2 and verify that you got an address in the range
707 10.0.2.x from the QEMU virtual DHCP server.
709 Note that @code{ping} is not supported reliably to the internet as it
710 would require root priviledges. It means you can only ping the local
713 When using the built-in TFTP server, the router is also the TFTP
716 When using the @option{-redir} option, TCP or UDP connections can be
717 redirected from the host to the guest. It allows for example to
718 redirect X11, telnet or SSH connections.
720 @node direct_linux_boot
721 @section Direct Linux Boot
723 This section explains how to launch a Linux kernel inside QEMU without
724 having to make a full bootable image. It is very useful for fast Linux
725 kernel testing. The QEMU network configuration is also explained.
729 Download the archive @file{linux-test-xxx.tar.gz} containing a Linux
730 kernel and a disk image.
732 @item Optional: If you want network support (for example to launch X11 examples), you
733 must copy the script @file{qemu-ifup} in @file{/etc} and configure
734 properly @code{sudo} so that the command @code{ifconfig} contained in
735 @file{qemu-ifup} can be executed as root. You must verify that your host
736 kernel supports the TUN/TAP network interfaces: the device
737 @file{/dev/net/tun} must be present.
739 When network is enabled, there is a virtual network connection between
740 the host kernel and the emulated kernel. The emulated kernel is seen
741 from the host kernel at IP address 172.20.0.2 and the host kernel is
742 seen from the emulated kernel at IP address 172.20.0.1.
744 @item Launch @code{qemu.sh}. You should have the following output:
748 Connected to host network interface: tun0
749 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
750 BIOS-provided physical RAM map:
751 BIOS-e801: 0000000000000000 - 000000000009f000 (usable)
752 BIOS-e801: 0000000000100000 - 0000000002000000 (usable)
753 32MB LOWMEM available.
754 On node 0 totalpages: 8192
758 Kernel command line: root=/dev/hda sb=0x220,5,1,5 ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe console=ttyS0
759 ide_setup: ide2=noprobe
760 ide_setup: ide3=noprobe
761 ide_setup: ide4=noprobe
762 ide_setup: ide5=noprobe
764 Detected 2399.621 MHz processor.
765 Console: colour EGA 80x25
766 Calibrating delay loop... 4744.80 BogoMIPS
767 Memory: 28872k/32768k available (1210k kernel code, 3508k reserved, 266k data, 64k init, 0k highmem)
768 Dentry cache hash table entries: 4096 (order: 3, 32768 bytes)
769 Inode cache hash table entries: 2048 (order: 2, 16384 bytes)
770 Mount cache hash table entries: 512 (order: 0, 4096 bytes)
771 Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
772 Page-cache hash table entries: 8192 (order: 3, 32768 bytes)
773 CPU: Intel Pentium Pro stepping 03
774 Checking 'hlt' instruction... OK.
775 POSIX conformance testing by UNIFIX
776 Linux NET4.0 for Linux 2.4
777 Based upon Swansea University Computer Society NET3.039
778 Initializing RT netlink socket
781 Journalled Block Device driver loaded
782 Detected PS/2 Mouse Port.
783 pty: 256 Unix98 ptys configured
784 Serial driver version 5.05c (2001-07-08) with no serial options enabled
785 ttyS00 at 0x03f8 (irq = 4) is a 16450
786 ne.c:v1.10 9/23/94 Donald Becker (becker@scyld.com)
787 Last modified Nov 1, 2000 by Paul Gortmaker
788 NE*000 ethercard probe at 0x300: 52 54 00 12 34 56
789 eth0: NE2000 found at 0x300, using IRQ 9.
790 RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
791 Uniform Multi-Platform E-IDE driver Revision: 7.00beta4-2.4
792 ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
793 hda: QEMU HARDDISK, ATA DISK drive
794 ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
795 hda: attached ide-disk driver.
796 hda: 20480 sectors (10 MB) w/256KiB Cache, CHS=20/16/63
799 Soundblaster audio driver Copyright (C) by Hannu Savolainen 1993-1996
800 NET4: Linux TCP/IP 1.0 for NET4.0
801 IP Protocols: ICMP, UDP, TCP, IGMP
802 IP: routing cache hash table of 512 buckets, 4Kbytes
803 TCP: Hash tables configured (established 2048 bind 4096)
804 NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
805 EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended
806 VFS: Mounted root (ext2 filesystem).
807 Freeing unused kernel memory: 64k freed
809 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
811 QEMU Linux test distribution (based on Redhat 9)
813 Type 'exit' to halt the system
819 Then you can play with the kernel inside the virtual serial console. You
820 can launch @code{ls} for example. Type @key{Ctrl-a h} to have an help
821 about the keys you can type inside the virtual serial console. In
822 particular, use @key{Ctrl-a x} to exit QEMU and use @key{Ctrl-a b} as
826 If the network is enabled, launch the script @file{/etc/linuxrc} in the
827 emulator (don't forget the leading dot):
832 Then enable X11 connections on your PC from the emulated Linux:
837 You can now launch @file{xterm} or @file{xlogo} and verify that you have
838 a real Virtual Linux system !
845 A 2.5.74 kernel is also included in the archive. Just
846 replace the bzImage in qemu.sh to try it.
849 qemu-fast creates a temporary file in @var{$QEMU_TMPDIR} (@file{/tmp} is the
850 default) containing all the simulated PC memory. If possible, try to use
851 a temporary directory using the tmpfs filesystem to avoid too many
852 unnecessary disk accesses.
855 In order to exit cleanly from qemu, you can do a @emph{shutdown} inside
856 qemu. qemu will automatically exit when the Linux shutdown is done.
859 You can boot slightly faster by disabling the probe of non present IDE
860 interfaces. To do so, add the following options on the kernel command
863 ide1=noprobe ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe
867 The example disk image is a modified version of the one made by Kevin
868 Lawton for the plex86 Project (@url{www.plex86.org}).
873 @section Linux Kernel Compilation
875 You can use any linux kernel with QEMU. However, if you want to use
876 @code{qemu-fast} to get maximum performances, you must use a modified
877 guest kernel. If you are using a 2.6 guest kernel, you can use
878 directly the patch @file{linux-2.6-qemu-fast.patch} made by Rusty
879 Russel available in the QEMU source archive. Otherwise, you can make the
880 following changes @emph{by hand} to the Linux kernel:
884 The kernel must be mapped at 0x90000000 (the default is
885 0xc0000000). You must modify only two lines in the kernel source:
887 In @file{include/asm/page.h}, replace
889 #define __PAGE_OFFSET (0xc0000000)
893 #define __PAGE_OFFSET (0x90000000)
896 And in @file{arch/i386/vmlinux.lds}, replace
898 . = 0xc0000000 + 0x100000;
902 . = 0x90000000 + 0x100000;
906 If you want to enable SMP (Symmetric Multi-Processing) support, you
907 must make the following change in @file{include/asm/fixmap.h}. Replace
909 #define FIXADDR_TOP (0xffffX000UL)
913 #define FIXADDR_TOP (0xa7ffX000UL)
915 (X is 'e' or 'f' depending on the kernel version). Although you can
916 use an SMP kernel with QEMU, it only supports one CPU.
919 If you are not using a 2.6 kernel as host kernel but if you use a target
920 2.6 kernel, you must also ensure that the 'HZ' define is set to 100
921 (1000 is the default) as QEMU cannot currently emulate timers at
922 frequencies greater than 100 Hz on host Linux systems < 2.6. In
923 @file{include/asm/param.h}, replace:
926 # define HZ 1000 /* Internal kernel timer frequency */
930 # define HZ 100 /* Internal kernel timer frequency */
935 The file config-2.x.x gives the configuration of the example kernels.
942 As you would do to make a real kernel. Then you can use with QEMU
943 exactly the same kernel as you would boot on your PC (in
944 @file{arch/i386/boot/bzImage}).
949 QEMU has a primitive support to work with gdb, so that you can do
950 'Ctrl-C' while the virtual machine is running and inspect its state.
952 In order to use gdb, launch qemu with the '-s' option. It will wait for a
955 > qemu -s -kernel arch/i386/boot/bzImage -hda root-2.4.20.img -append "root=/dev/hda"
956 Connected to host network interface: tun0
957 Waiting gdb connection on port 1234
960 Then launch gdb on the 'vmlinux' executable:
965 In gdb, connect to QEMU:
967 (gdb) target remote localhost:1234
970 Then you can use gdb normally. For example, type 'c' to launch the kernel:
975 Here are some useful tips in order to use gdb on system code:
979 Use @code{info reg} to display all the CPU registers.
981 Use @code{x/10i $eip} to display the code at the PC position.
983 Use @code{set architecture i8086} to dump 16 bit code. Then use
984 @code{x/10i $cs*16+*eip} to dump the code at the PC position.
987 @section Target OS specific information
991 To have access to SVGA graphic modes under X11, use the @code{vesa} or
992 the @code{cirrus} X11 driver. For optimal performances, use 16 bit
993 color depth in the guest and the host OS.
995 When using a 2.6 guest Linux kernel, you should add the option
996 @code{clock=pit} on the kernel command line because the 2.6 Linux
997 kernels make very strict real time clock checks by default that QEMU
998 cannot simulate exactly.
1002 If you have a slow host, using Windows 95 is better as it gives the
1003 best speed. Windows 2000 is also a good choice.
1005 @subsubsection SVGA graphic modes support
1007 QEMU emulates a Cirrus Logic GD5446 Video
1008 card. All Windows versions starting from Windows 95 should recognize
1009 and use this graphic card. For optimal performances, use 16 bit color
1010 depth in the guest and the host OS.
1012 @subsubsection CPU usage reduction
1014 Windows 9x does not correctly use the CPU HLT
1015 instruction. The result is that it takes host CPU cycles even when
1016 idle. You can install the utility from
1017 @url{http://www.user.cityline.ru/~maxamn/amnhltm.zip} to solve this
1018 problem. Note that no such tool is needed for NT, 2000 or XP.
1020 @subsubsection Windows 2000 disk full problems
1022 Currently (release 0.6.0) QEMU has a bug which gives a @code{disk
1023 full} error during installation of some releases of Windows 2000. The
1024 workaround is to stop QEMU as soon as you notice that your disk image
1025 size is growing too fast (monitor it with @code{ls -ls}). Then
1026 relaunch QEMU to continue the installation. If you still experience
1027 the problem, relaunch QEMU again.
1029 Future QEMU releases are likely to correct this bug.
1031 @subsubsection Windows XP security problems
1033 Some releases of Windows XP install correctly but give a security
1036 A problem is preventing Windows from accurately checking the
1037 license for this computer. Error code: 0x800703e6.
1039 The only known workaround is to boot in Safe mode
1040 without networking support.
1042 Future QEMU releases are likely to correct this bug.
1044 @subsection MS-DOS and FreeDOS
1046 @subsubsection CPU usage reduction
1048 DOS does not correctly use the CPU HLT instruction. The result is that
1049 it takes host CPU cycles even when idle. You can install the utility
1050 from @url{http://www.vmware.com/software/dosidle210.zip} to solve this
1053 @chapter QEMU PowerPC System emulator invocation
1055 Use the executable @file{qemu-system-ppc} to simulate a complete PREP
1056 or PowerMac PowerPC system.
1058 QEMU emulates the following PowerMac peripherials:
1064 PCI VGA compatible card with VESA Bochs Extensions
1066 2 PMAC IDE interfaces with hard disk and CD-ROM support
1072 VIA-CUDA with ADB keyboard and mouse.
1075 QEMU emulates the following PREP peripherials:
1081 PCI VGA compatible card with VESA Bochs Extensions
1083 2 IDE interfaces with hard disk and CD-ROM support
1087 NE2000 network adapters
1091 PREP Non Volatile RAM
1093 PC compatible keyboard and mouse.
1096 QEMU uses the Open Hack'Ware Open Firmware Compatible BIOS available at
1097 @url{http://site.voila.fr/jmayer/OpenHackWare/index.htm}.
1099 You can read the qemu PC system emulation chapter to have more
1100 informations about QEMU usage.
1102 @c man begin OPTIONS
1104 The following options are specific to the PowerPC emulation:
1109 Simulate a PREP system (default is PowerMAC)
1111 @item -g WxH[xDEPTH]
1113 Set the initial VGA graphic mode. The default is 800x600x15.
1120 More information is available at
1121 @url{http://jocelyn.mayer.free.fr/qemu-ppc/}.
1123 @chapter QEMU User space emulator invocation
1125 @section Quick Start
1127 In order to launch a Linux process, QEMU needs the process executable
1128 itself and all the target (x86) dynamic libraries used by it.
1132 @item On x86, you can just try to launch any process by using the native
1136 qemu-i386 -L / /bin/ls
1139 @code{-L /} tells that the x86 dynamic linker must be searched with a
1142 @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):
1145 qemu-i386 -L / qemu-i386 -L / /bin/ls
1148 @item On non x86 CPUs, you need first to download at least an x86 glibc
1149 (@file{qemu-runtime-i386-XXX-.tar.gz} on the QEMU web page). Ensure that
1150 @code{LD_LIBRARY_PATH} is not set:
1153 unset LD_LIBRARY_PATH
1156 Then you can launch the precompiled @file{ls} x86 executable:
1159 qemu-i386 tests/i386/ls
1161 You can look at @file{qemu-binfmt-conf.sh} so that
1162 QEMU is automatically launched by the Linux kernel when you try to
1163 launch x86 executables. It requires the @code{binfmt_misc} module in the
1166 @item The x86 version of QEMU is also included. You can try weird things such as:
1168 qemu-i386 /usr/local/qemu-i386/bin/qemu-i386 /usr/local/qemu-i386/bin/ls-i386
1173 @section Wine launch
1177 @item Ensure that you have a working QEMU with the x86 glibc
1178 distribution (see previous section). In order to verify it, you must be
1182 qemu-i386 /usr/local/qemu-i386/bin/ls-i386
1185 @item Download the binary x86 Wine install
1186 (@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page).
1188 @item Configure Wine on your account. Look at the provided script
1189 @file{/usr/local/qemu-i386/bin/wine-conf.sh}. Your previous
1190 @code{$@{HOME@}/.wine} directory is saved to @code{$@{HOME@}/.wine.org}.
1192 @item Then you can try the example @file{putty.exe}:
1195 qemu-i386 /usr/local/qemu-i386/wine/bin/wine /usr/local/qemu-i386/wine/c/Program\ Files/putty.exe
1200 @section Command line options
1203 usage: qemu-i386 [-h] [-d] [-L path] [-s size] program [arguments...]
1210 Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)
1212 Set the x86 stack size in bytes (default=524288)
1219 Activate log (logfile=/tmp/qemu.log)
1221 Act as if the host page size was 'pagesize' bytes
1225 @chapter Compilation from the sources
1229 Read the @file{README} which gives the related information.
1234 @item Install the current versions of MSYS and MinGW from
1235 @url{http://www.mingw.org/}. You can find detailed installation
1236 instructions in the download section and the FAQ.
1239 the MinGW development library of SDL 1.2.x
1240 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
1241 @url{http://www.libsdl.org}. Unpack it in a temporary place, and
1242 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
1243 directory. Edit the @file{sdl-config} script so that it gives the
1244 correct SDL directory when invoked.
1246 @item Extract the current version of QEMU.
1248 @item Start the MSYS shell (file @file{msys.bat}).
1250 @item Change to the QEMU directory. Launch @file{./configure} and
1251 @file{make}. If you have problems using SDL, verify that
1252 @file{sdl-config} can be launched from the MSYS command line.
1254 @item You can install QEMU in @file{Program Files/Qemu} by typing
1255 @file{make install}. Don't forget to copy @file{SDL.dll} in
1256 @file{Program Files/Qemu}.
1260 @section Cross compilation for Windows with Linux
1264 Install the MinGW cross compilation tools available at
1265 @url{http://www.mingw.org/}.
1268 Install the Win32 version of SDL (@url{http://www.libsdl.org}) by
1269 unpacking @file{i386-mingw32msvc.tar.gz}. Set up the PATH environment
1270 variable so that @file{i386-mingw32msvc-sdl-config} can be launched by
1271 the QEMU configuration script.
1274 Configure QEMU for Windows cross compilation:
1276 ./configure --enable-mingw32
1278 If necessary, you can change the cross-prefix according to the prefix
1279 choosen for the MinGW tools with --cross-prefix. You can also use
1280 --prefix to set the Win32 install path.
1282 @item You can install QEMU in the installation directory by typing
1283 @file{make install}. Don't forget to copy @file{SDL.dll} in the
1284 installation directory.
1288 Note: Currently, Wine does not seem able to launch
1293 The Mac OS X patches are not fully merged in QEMU, so you should look
1294 at the QEMU mailing list archive to have all the necessary