Re: [PATCH v3] x86/cpu/amd: Enable the fixed Instructions Retired counter IRPERF

From: Borislav Petkov
Date: Tue Feb 18 2020 - 16:54:20 EST

On Tue, Feb 18, 2020 at 03:35:25PM -0600, Kim Phillips wrote:
> 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.

How is userspace going to check it? perf tool or people *can* check it?
If perf is going to check it then I'm fine with having the bug bit in
/proc/cpuinfo along with a patch for perf adding usage for it.

If not and people in userspace can maybe check it but they probably
won't then adding that bug bit would be a waste of bit.

> Let me know if you'd like me to send a v4, or if you will just apply
> this version of yours.

I can take the simpler version for now. If you still want to have perf
tool check the bit, you could submit a new patch adding that bug bit
along with a perf tool patch using it...