VM: Automatic Windows driver support

[garrett]

When adding a shared folder to a Windows guest I had to find a guide to find and install relevant drivers. The guides are easy to find, however.

Originally posted by @Betonhaus in #680 (comment)

[garrett]

The Windows driver ISO link is at https://github.com/virtio-win/virtio-win-pkg-scripts/blob/master/README.md

The direct link from that document is https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/stable-virtio/virtio-win.iso (for the stable version; there is a "latest" version too, which I guess is probably built from the main branch).

There's also an EXE @ https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/latest-virtio/virtio-win-guest-tools.exe

We could download (then cache for future VMs) and auto-mount the ISO when creating a Windows VM.

Or we could copy the EXE into the Windows VM, like to the Desktop so it's easy to see, perhaps. The ISO one feels like that'd be more possible and less fragile. However, the EXE is 29 MB whereas the ISO is 692 MB, so if we can use the EXE, that'd be better.

[Betonhaus]

Reference for the steps required
Requires WinFSB and virtio-win-guest-tools.exe and then enabling the VirtIO-FS Service, I don't see how cockpit-machines can simplify that aside from making their own installer for the guest tools, maybe just provide a link to instructions and the installer beside the button for adding shared volumes?

[garrett]

The Windows drivers I was talking about were more to make the graphics adaptable (so it resizes to the available size) than to have transparent desktop sharing.

Adding the ISO as a disk that's mounted is likely possible, and copying the EXE (which is smaller in filesize than the ISO) over to the desktop or something like that is probably possible too.

"WinFSB" is probably out of scope, but anything simple that can be done to make it easier or at least not get in the way of doing things like that would be good, of course.