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
