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
