On Fri, 6 May 2022, Arnd Bergmann wrote: > > So what happens if the instruction is given an I/O rather than memory BAR > > as the relevant argument? Is the address space indicator bit (bit #0) > > simply ignored or what? > > Not sure. My best guess is that it would actually work as you'd expect, > but is deliberately left out of the architecture specification so they don't > have to to validate the correctness. Note that only a small number of > PCIe cards are actually supported by IBM, and I think the firmware > only passes devices to the OS if they are whitelisted. That makes sense, thanks! Maciej
