VM reboot: mount you must specify the filesystem type kernel panic

On a kvm I was running an fio command to test the io of the system, and the server froze. I rebooted the VM, and I get this error on boot.


mount: you must specify the filesystem type
.......


kernel panic - not syncing: Attempted to kill the init!

Does anyone have any ideas how to repair this?

thanks.
myles.