Hi Borislav,
On 2/18/20 5:20 AM, Borislav Petkov wrote:
On Fri, Feb 14, 2020 at 02:18:05PM -0600, Kim Phillips wrote:
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index f3327cb56edf..8979d6fcc79c 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -404,5 +404,6 @@ #define X86_BUG_SWAPGS X86_BUG(21) /* CPU is affected by speculation through SWAPGS */ #define X86_BUG_TAA X86_BUG(22) /* CPU is affected by TSX Async Abort(TAA) */ #define X86_BUG_ITLB_MULTIHIT X86_BUG(23) /* CPU may incur MCE during certain page attribute changes */ +#define X86_BUG_IRPERF X86_BUG(24) /* CPU is affected by Instructions Retired counter Erratum 1054 */
Do you need this bug flag at all?
If the only reason for its existence is to check it before setting the MSR bit enabling IRPERF, then you don't need it. Or is there any particular reason why it should show in /proc/cpuinfo?
IOW, does this work too?
Yes, that works quite nicely, and saves us a bug bit.
The only reason to have it show in /proc/cpuinfo is for userspace, but they can check for a nonzero count prior to using, instead.
Let me know if you'd like me to send a v4, or if you will just apply this version of yours.
Thanks,
Kim