QEMU Cheat Sheet

QEMU Cheat Sheet

build a bootable ISO image file of linux system and use it on VMs

Install and use VirtualBox on Linux

1. install virtualbox
   $ apt-get install virtualbox-ose
   
2. add the current user to the group vboxusers
   $ adduser $USER vboxusers
   
3. insert the relative modules to kernel
   $ /etc/init.d/vboxdrv start
   
4. start virtualbox, follow the prompt, and boot a system from the iso file
   $ virtulbox

Use Qemu to boot iso file

1. installed first
   $ apt-get install qemu
   
2. boot the iso file
   $ qemu -m 128M -cdrom minios.iso -boot d -no-kqemu
   or boot a floppy image file
   $ qemu -m 64 -boot a -fda boot.img -no-kqemu
   
3. to speed up the qemu, please install kqemu, the basic steps are:
   $ sudo apt-get install kqemu-source kernel-package linux-source build-essential
$ cd /usr/src/linux
$ sudo module-assistant prepare kqemu
$ sudo module-assistant build kqemu
$ sudo module-assistant install kqemu
$ sudo depmod -a
$ sudo modprobe kqemu
$ sudo mknod /dev/kqemu c 250 0
$ sudo chmod 666 /dev/kqemu

   now, there is no need to use the -no-kqemu option when using qemu and the
   running speed of qemu will be accelerated.

Build the network between VMs and the HOST system/Internet

Boot linux kernel with Qemu

1. create a virtual disk image file
   $ qemu-img create -f qcow linux.img 1G
   

   In this command the -f option is for the disk image format. The following formats are supported: vfat, vpc, bochs, dmg, cloop, vmdk, cow, qcow, and raw, depending on the OS. See also: .img and .iso. The supported filesystem formats are abbreviations for:

   • vfat - Virtual VFAT
   • vpc - Virtual PC
   • bochs - BOCHS filesystem
   • dmg - macintosh Disk iMaGe
   • cloop - linux Compressed LOOP
   • vmdk - vmware Virtual Machine DisK format
   • qcow - Qemu Copy-On-Write
   • raw - RAW filesystem (no special format)
   • cow - user mode linux Copy-On-Write
   
   
2. boot the kernel using qemu with the -S option
   sudo qemu -s -S -no-kqemu -kernel ../SSS/arch/i386/boot/bzImage -hda linux.img -append "root=/dev/hda"(See also Breakint at boot startup on qemu)
   
3. switch it to the qemu command line via typing the
   following command to start the gdb server:
   $ gdbserver 1234
   
4. start a new terminal on your HOST system and execute gdb to
   debug the linux kernel.
   $ gdb /path/to/vmlinux
(gdb) target remote localhost:1234

一种方便的Linux内核调试方法：VirtualBox + KGDB