Re: [PATCH v3 6/9] x86: resctrl: pseudo_lock: Fix to restore to original value when re-enabling hardware prefetch register

[Dave Hansen]

On 4/19/22 20:02, Kohei Tarumizu wrote:
> The current pseudo_lock.c code overwrittes the value of the
> MSR_MISC_FEATURE_CONTROL to 0 even if the original value is not 0.
> Therefore, modify it to save and restore the original values.

It would be nice to mention that the wrmsr()'s in this patch are only
done inside of an interrupt-disabled region.  Without that little tidbit
of information, it's not obviously correct that the smp_call_function()
in patch 8/9 is correct.

The x86 code here looks reasonable otherwise.  It's a little bit of a
shame that this is *ONLY* for BROADWELL_X for now, but I assume you were
just conservative about it because that's all you have to test on.