Re: [regression] commit d298b03506d3 ("x86/fpu: Restore the masking out of reserved MXCSR bits")

From: Borislav Petkov
Date: Thu Oct 14 2021 - 10:58:08 EST


On Thu, Oct 14, 2021 at 05:43:14PM +0300, Ville Syrjälä wrote:
> Hmm. Actually I just stared at the code a bit more it looks
> a bit funny. Was it supposed to do this instead?
>
> - fpu->state.fxsave.mxcsr &= ~mxcsr_feature_mask;
> + fpu->state.fxsave.mxcsr &= mxcsr_feature_mask;

Whoops, I had it like that in the original patch:

https://lore.kernel.org/all/163354193576.25758.8132624386883258818.tip-bot2@tip-bot2/

I blame tglx. :-)

Does it work if you remove the mask negation "~"?

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette