Before 02860f2, there was an enum for abstracting over split and packed virtqueues:

pub enum Virtq {
    Packed(PackedVq),
    Split(SplitVq),
}

Currently, we are using a trait via Rc<dyn Virtq> instead of Rc<Virtq>.

We need to consider automating the previous enum-based static dispatch via enum_dispatch for performance.
This would be a nice fit because restricting the set of implementors is no problem for us.

This might not have a too much of an impact, depending on how hot these dynamic dispatches are right now.