Installing windows
To use virtio devices under windows, you'll need the drivers iso from the fedora project.
For the installation, you should put the windows install iso in the cdrom and set the bootoptions to "d".
Additionally, a second cdrom can be defined through the "custom" field like "-drive file=/path/to/virtio.iso,media=cdrom".
That way you should be able to load the required vio storage driver for the install and after that you can load the ethernet driver as well as the rng driver.