Development platform virtualization using qemu

Development platform virtualization using qemu

• 1.
  Platform Virtualization (i386) for kernelbooting, debugging and testing Requirements Linux machine (Virtual or Real) Qemu, busybox, initramfs, kernel packages : build-essential, libncurses5-dev, vnc4server
• 2.
  Installations Qemu: is a generic and open source machine emulator and virtualizer. http://wiki.qemu.org Method 1: Install a virtualbox virtual manager to run ubuntu 12.04 in windows 7. Then updated the ubuntu packages , means the initial updates. Then installed qemu , # sudo apt-get install qemu after installation check whether the qemu is installed correctly, run the command, # qemu-system-i386 popup a black qemu windows shows some no disk found notification. Fig 1 : Qemu window
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  Method 2: Download thelatest qemu source from http://wiki.qemu.org. Extract the source and install # tar xf qemu-1.2.0.tar.bz2 # cd qemu-1.2.0.tar.bz2 # sudo ./configure --target-list=i386-softmmu # sudo make # sudo make install Check the qemu working, run command # qemu-system-i386 popup a black qemu windows shows some no disk found notification [Fig. 1]. Fig 2 : working qemu window of a custom kernel
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  Busybox: The Swiss Army Knife of Embedded Linux http://busybox.net Download latest busybox tar from the website and extract it. #tar xf busybox-1.20.2.tar.bz2 #cd busybox-1.20.2 #make allnoconfig #make menuconfig Select appropriate options in menuconfig. busybox settings -> build options -> static binary[essential] coreutils -> enable cat, touch, chmod, chroot, cp, echo, ln, ls, mkdir, mknod, pwd, rm, rmdir console utils -> clear editor -> vi find -> find, grep init -> poweroff, init [essential] linux system utils -> mdev, mount[essential] network utils -> ping, arp, httpd, ifconfig shells -> ash, choose which shell is aliased to sh & bash name[essential] save the configuration. #make #make install make install command copies the binaries generated to _install directory.
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  initramfs: is a root filesystem which is embedded into the kernel and loaded at an early stage of the boot process. Create a main directory initramfs #mkdir initramfs #cd initramfs Create a basic folder structure #mkdir -pv bin lib dev etc mnt/root proc root sbin sys Copy some default device nodes to device directory #sudo cp -va /dev/{null,console,tty} dev Now copy the busybox binaries in _install directory into initramfs. #cd busybox-1.20.2 #sudo cp -avR _install/* ../initramfs Fig 3 : busybox copy to initramfs
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  Create a initscript in initramfs directory #cd initramfs #sudo gedit init Fig 4: init script Change the permission settings of init script to executable #sudo chmod +x init Fig 5 : initramfs folder structure
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  Optional Steps forcpio archive[Optional] #find . -print0 | cpio --null -ov --format=newc> ../initram.cpio Fig 6 : copy files to archives
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  Kernel: Linux isa clone of the operating system Unix, written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. http://www.kernel.org/ Download a stable kernel and untar it, Fig 7 : Kernel.org # tar xf linux-2.6.34.tar.bz2 # cd linux-2.6.34 # make allnoconfig # make menuconfig select appropriate options. general setup -> initial RAM filesystem and RAM disk support -> initramfs source [/home/premjith/linux_qemu/initramfs] Bus options -> PCI support ELF Format/Emulation -> Kernel support ELF binaries Networking Support [y] -> Networking options ->packet socket ->unix domain socket
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  -> TCP/IP networking Device drivers -> ATA -> Network device support File systems -> second extended FS support -> ext3 Kernel hacking -> kernel debugging -> compile the kernel with debug info Fig 8 : kernel configuration save the configuration and run make # make It generates a bzImage of kernel in arch/x86/boot/
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  Virtual booting ofkernel image in Qemu #qemu-system-i386 -kernel linux-2.6.34/arch/x86/boot/bzImage Fig 9 : final qemu window