On Sun, Aug 02, 2020 at 08:46:48PM +0200, Borislav Petkov wrote: > On Sun, Aug 02, 2020 at 07:28:00PM +0200, Saheed Bolarinwa wrote: > > Because the value ~0 has a meaning to some drivers and only > > No, ~0 means that the PCI read failed. For *every* PCI device I know. Wait, I'm not convinced yet. I know that if a PCI read fails, you normally get ~0 data because the host bridge fabricates it to complete the CPU load. But what guarantees that a PCI config register cannot contain ~0? If there's something about that in the spec I'd love to know where it is because it would simplify a lot of things. I don't think we should merge any of these patches as-is. If we *do* want to go this direction, we at least need some kind of macro or function that tests for ~0 so we have a clue about what's happening and can grep for it. Bjorn