This comes from a site: http://www.neowin.net/forum/topic/784138-howto-boot-existing-ubuntu-partition-using-virtualbox-inside-windows/
This is a tutorial I wrote up and posted up on my blog.
I recently got Windows 7 and Ubuntu running in a dualboot. However, since I’m using more of Windows now I figured I should probably find a way to run Ubuntu inside my Windows. VM’s are great, but it’d be better if I can actually boot into my existing Ubuntu partition. So I searched the web and kept on finding tutorials on how to boot existing XP partitions inside Windows. So I decided to extrapolate from those tutorials and work my way through it. I’ll be writing how I did it here.
Before we begin, you should have a dual boot setup. I will NOT be showing you how to setup a dual boot, if you need help plenty of other guides out there.
Step 1: Creating a grub boot iso
The grub iso file will allow you to specify which partition to boot into.
1. Boot into Ubuntu
2. We create the folders and copy the necessary files to setup an isoRun the command:
cd; mkdir -p iso/boot/grub; cp /usr/lib/grub/*-pc/stage2_eltorito /boot/grub/menu.lst iso/boot/grub
3. Configure your ~/iso/boot/grub menu.lst file to boot your target OS (in this case Ubuntu). Remove the “savedefault” option from your target entry if it exists.
4. We now create the bootable iso fileRun the command:
cd; mkisofs -R -b boot/grub/stage2_eltorito -no-emul-boot -boot-load-size 4 -boot-info-table -o grub.iso iso
5. Move the iso to a location that’ll be accessable by your Windows partition
Step 2: Creating the .vmdk file
This creates a file which tells Virtualbox what partition to actually load as the harddrive. Unfortunately, unlike VMWare Workstation, Virtualbox does not support a GUI interface for selecting RAW hard disks as the “virtual hard drive”.
1. Boot into Windows
2. cd into the directory you installed virtualbox
3. We find the partition number that needs to be mountedRun the command:
VBoxManage.exe internalcommands listpartitions -rawdisk \\.\PhysicalDrive1
(where 1 is the number of the hard drive ubuntu is installed on. E.g. Master should be 0, you’re second hard-drive should be 1 etc…The output should be something like:
Number Type StartCHS EndCHS Size (MiB) Start (Sect)
1 0×07 0 /32 /33 1023/254/63 902023 2048
5 0×83 1023/254/63 1023/254/63 49677 1847346543
6 0×82 1023/254/63 1023/254/63 2164 1949086188
In this example, my Ubuntu partition is number 5 and the swap is number 6
4. We now create the VMDK file with the given informationRun the command:
VBoxManage.exe internalcommands createrawvmdk -filename C:\path\ubuntu.vmdk -rawdisk \\.\PhysicalDrive1 -partitions 5,6 -register
Step 3: Setup Virtualbox
Now everything should be ready to setup Virtualbox. Create a new virtual machine. Select the .vmdk file we just created as the hard drive and mount the grub.iso file we created at Step 1. If everything was successful Ubuntu should boot up nicely.