On 1/26/2018 4:10 PM, Borislav Petkov wrote: > On Fri, Jan 26, 2018 at 09:59:44PM +0000, David Woodhouse wrote: >> If we wanted to do this kind of thing, we'd do it the other way round. >> Turn the *Intel* feature into both 'IBRS' and 'IBPB' CPU-visible >> features, and have those defined in the AMD word. > > You lost me here: have those defined in the AMD word? > >> Then use virtual bits with "" for the software features, since we >> don't want *those* to appear in /proc/cpuinfo. > > Whatever we do, I think it would be most consistent to have three > strings, *both* on Intel and AMD visible in cpuinfo: "ibrs", "ibpb" and > "stibp" so that there's no confusion what is enabled on each box. > > Now, those three can be the *virtual* features which get set by the > actual CPUID features on init. And the latter, the *actual* CPUID > features don't need to be visible in cpuinfo: people shouldn't care > whether "spec_ctrl" on Intel and "pred_cmd" on AMD both mean "ibpb". It > should be simply "ibpb" on both vendors in cpuinfo. > > Ditto for the others. > > This way you have one unified message of what is enabled on *any* box.
That sounds good to me. Thanks, Tom >
