On Mon, 17 Feb 2025 at 18:08, Borislav Petkov <bp@xxxxxxxxx> wrote: > > On Mon, Feb 17, 2025 at 05:56:32PM +0100, Brendan Jackman wrote: > > Er, hold on, what chunk can be whacked? Do you mean delete the ability > > to set clearcpuid by number? There are still features with no name. > > Really, which ones? I just mean the ones without a "name" in cpufeatures.h, e.g. #define X86_FEATURE_MSR_SPEC_CTRL ( 7*32+16) /* MSR SPEC_CTRL is implemented */ > Are you saying you want to turn off *arbitrary* features? Not only what gets > advertized in /proc/cpuinfo? You can already clear arbitrary ones with clearcpuid. But for bugs, they all have a name. I was thinking that this was because they are defined by the kernel, that's what I meant by "It t doesn't make sense for a bug not to have a name", although now I think about it we could totally have a bug and not give it a user-visible name if we wanted to. Anyway, still think the current logic is what we want here: - The new setcpuid should be consistent with the existing clearcpuid, i.e. accept numbers for the same things clearcpuid does. - There are currently no bugs without names so for those, require the string for both setcpuid and clearcpuid. If we wanted to we could add number support later.
