How can I make Windows Server 2012 running on KVM boot with virtio rather than IDE?
- Attach a new VirtIO disk to your VM, whether it is online or offline.
- When online, Windows will recognize the new disk and ask for drivers. Install virtIO drivers.
- After successful driver installation, shutdown your VM.
- With VM offline, remove the disk attached on step 1.
- With VM offline, change type of original VM disk to VirtIO.
- Boot your VM.
Windows won't complain, because you already have the drivers (installed on step 2).