On Thu, 17 Oct 2024 16:46:35 +0000 "Luck, Tony" <tony.luck@xxxxxxxxx> wrote: > > What does the I/O hole correspond to in the system? > > PCIe mmio mapped space. 32-bit devices must have addresses below 4G > so X86 systems have a physical memory map that looks like: > > 0 - 2G: RAM > 2G-4G: MMIO > 4G-end of memory: RAM > end of memory-infinity: 64-bit MMIO > > Depending on how much MMIO there is different systems put the > dividing line at other addresses than 2G. Ah, thanks. So this weird cache setup might be not quite linear module N aliases as described in the ACPI spec (System vs host physical addresses I guess). Had wrong mental model :( Ouch. > > -Tony >
