On Sun, Mar 12, 2023 at 08:01:55PM +0800, Huang Rui wrote: > There is an second stage translation between the guest machine address > and host machine address in Xen PVH/HVM. The PCI bar address in the xen > guest kernel are not translated at the second stage on Xen PVH/HVM, so I'm confused by the sentence above, do you think it could be reworded or expanded to clarify? PCI BAR addresses are not in the guest kernel, but rather in the physical memory layout made available to the guest. Also, I'm unsure why xen_initial_domain() needs to be used in the conditional below: all PV domains handle addresses the same, so if it's not needed for a PV dom0 it's likely not needed for a PV domU either. Albeit it would help to know more about what AMDGPU_PASSTHROUGH_MODE implies. Thanks, Roger.