How to change the controller driver of a Windows VM to VirtIO¶
Add a new virtio disk (a small one, even 100mb will be enough. We will not be using it)
Use virt manager
or
virsh edit
Boot the machine
Make sure Windows recognises the disk controller and has the drivers for it (the disk should be visible in diskmgmt.msc)
Set boot to fail safe mode
Launch an elevated command prompt
Type
bcdedit /set {current} safeboot minimal
Shut down
Change the main disk to virtio
Boot. Now get into the admin prompt and disable failsafe mode.
Launch an elevated command prompt
Type
bcdedit /deletevalue {current} safeboot
Reboot and make sure everything works.
Now you can shut down the machine and remove the small virtio disk