Just saw this, thought I might share some info.

It seems KVM uses different storage drivers than VMWare, so you might need to rebuild the initramfs file in the /boot directory. You will need an RHEL/OEL/Centos install disc (ISO) and use the rescue mode to drop to a shell, backup the current file and recreate it. The dracut command will detect the new environment and add the necessary drivers to the file.

I dont remember the steps from the top of my head, but I hope this points you in the right direction.