Thanks Gerd, Dave and Eduardo for the prompt responses! So, I understand that when we use "-host-physical-bits", we are passing the *real* number for the guest, correct? So, in this case we can trust that the guest physbits matches the true host physbits.
What if then we have OVMF relying in the physbits *iff* "-host-phys-bits" is used (which is the default in RH and a possible machine configuration on libvirt XML in Ubuntu), and we have OVMF fallbacks to 36-bit otherwise? Now, regarding the problem "to trust or not" in the guests' physbits, I think it's an orthogonal discussion to some extent. It'd be nice to have that check, and as Eduardo said, prevent migration in such cases. But it's not really preventing OVMF big PCI64 aperture if we only increase the aperture _when "-host-physical-bits" is used_. Thanks, Guilherme
