I had VT-x disabled and got [0.491424] BUG: unable to handle kernel <1> which repeats itself all the way down the screen. I turned VT-x on and was able to boot. KEEP IN MIND, that when you check the Enable VT-x/AMD-V checkbox once, that does NOT enable it!!! That just puts it into a grayed state. Clicking it a second time enables it.