lkml.org 
[lkml]   [2018]   [Jan]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86/cpufeatures: Cleanup AMD speculation feature bits
On Fri, Jan 26, 2018 at 06:45:18PM +0000, David Woodhouse wrote:
> On Fri, 2018-01-26 at 19:41 +0100, Borislav Petkov wrote:
> > +#define X86_FEATURE_AMD_IBPB           (13*32+12) /* "" Indirect Branch Prediction Barrier MSR */
>
> Stray quotes.

No no, those quotes are magical. :)

They don't show the string in /proc/cpuinfo, see arch/x86/kernel/cpu/mkcapflags.sh

> > +#define X86_FEATURE_IBRS               (13*32+14) /* Indirect Branch Restricted Speculation */
>
> Please don't call it that. Call it X86_FEATURE_AMD_IBRS and leave
> X86_FEATURE_IBRS to parallel X86_FEATURE_IBPB as the *software* bit
> which is vendor-independent.

Do we have a X86_FEATURE_IBRS bit?

If so, then this bit should become

#define X86_FEATURE_AMD_IBRS (13*32+14) /* "" Speculation Control MSR only (AMD) */

*with* the magic quotes.

--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

\
 
 \ /
  Last update: 2018-01-26 19:50    [W:1.394 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site