> For HVMLite, there is specifically no qemu, and we need something which
> can function when we want PCI Passthrough to work.  I am quite confident
> that the correct solution here is to have a basic host bridge/root port
> implementation in Xen (as we already have 80% of this already), at which
> point we don't need any qemu interaction for PCI Passthough at all, even
> for HVM guests.

Could you expand on this a bit?

I am asking b/c some time ago I wrote in Xen code to construct a full view
of the bridges->devices (and various in branching) so that I could renumber
the bus values and its devices (expand them) on bridges. This was solely done
so that I could use SR-IOV devices on non-SR-IOV capable BIOSes.

I am wondering how much of the basic functionality (enumeration, keeping
track, etc) could be worked in this 'basic host bridge/root port' implementation
idea of yours.

Attaching the patches.