For windows VM conversions, we use libguestfs to mount the virtio-win.iso and pull out content. Internally this is via the functions inject_virtio_win_drivers, inject_qemu_ga, inject_blnsrv.

Unfortunately each call launches its own guestfs appliance image. This slows down the install but worse IMO is how much it balloons the debug logs. In my testing with a basic win11 VM conversion, the log is ~56k lines, and pulling out this content is line ~9k -> ~51k, which is 3/4 the log size.

If we reworked things to use a single appliance launch it's possible we could cut the debug log size in half.

Relatedly if we stop using the iso by default, as tracked in https://issues.redhat.com/browse/RHEL-124843, then log is cut even more. But we should probably do the iso cleanup regardless since using iso is still a valid usecase, and I suspect most of the code rework will be valid for both cases.