I have a great MacBook Pro with awesome retina display, but I mostly run Windows 7 on it through bootcamp. Given that I often have to make iOS related tests, and that switching back and forth between OSX and Windows 7 was quite painful, I decided to try to run OSX as a virtual OS within Windows instead of Windows as a virtual OS within OSX.
If you want to do the same here are the simple things you need to do
1. Open regedit to export a backup of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\AppleHFS and HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\AppleMNT
2. Keep regedit opened and delete HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\AppleHFS and HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\AppleMNT
3. Reboot and make sure the OSX drive is not visible anymore as D: drive
4. Run in command line “C:\Program Files\Oracle\VirtualBox\VBoxManage.exe” internalcommands createrawvmdk -filename c:\RawAppleDisk.vmdk -rawdisk \\.\PhysicalDrive0
5. Open VirtualBox, create a new type “Mac OS X” with version “Mac OS X (64-bit)” virtual machine.
6. When asked to create a drive, select “Use an existing virtual hard drive file” and click the orange folder button, select the RawAppleDisk.vmdk that you created in step #4, it should be at the root of C: but you can move it anywhere you like before adding it to the virtual machine.
Et voila! Now your virtual machine should boot and run OS X as a virtual OS within Windows 7 running native on genuine Apple hardware