Fix Ubuntu VMs hanging in boot

转载：http://www.andre-richter.com/2014/04/how-to-fix-ubuntu-vms-hanging-at-boot.html

How to fix Ubuntu VMs hanging at boot in KVM / virt-manager

I have a Ubuntu 13.04 box which I use as a KVM host for several virtual machines. Using virt-manager, you can easily install 13.04 VMs without any difficulties, until you reboot the VM after installation.
In my setup, the VMs will hang up every time, the last thing visible in the boot console being the fsck utility.

I found out that you can fix this issue by changing the video adapter type for the VM. The default adapter is set to cirrus. Changing it to qxl or vga solved the problem for me.

I did not investigate further why this bug happens. qxl apparently has more video ram which might be a clue, but vga does not and it also works.