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

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Date:   Thu, 14 Oct 2021 21:46:50 +0300
From:   Ville Syrjälä <ville.syrjala@...ux.intel.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Ser Olmy <ser.olmy@...tonmail.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [regression] commit d298b03506d3 ("x86/fpu: Restore the masking
 out of reserved MXCSR bits")

On Thu, Oct 14, 2021 at 08:01:24PM +0200, Borislav Petkov wrote:
> On Thu, Oct 14, 2021 at 08:45:33PM +0300, Ville Syrjälä wrote:
> > That ~ was indeed the problem. With it gone the machine is happy again.
> > 
> > I presume you'll turn this into a real patch?
> 
> Actually, you found it and you should be the one to write it and do the
> honors. Unless you don't want to - then I can do it.

I figured you can write a reasonably succinct commit message, instead
of having me ramble on incoherently. ATM I don't even know what mxcsr
is or why clobbering it would cause floating point exceptions with
sse specifically.

But I can certainly ramble, if you prefer that.

> 
> If you do, pls add 
> 
> Ser Olmy <ser.olmy@...tonmail.com>
> 
> to Cc so that he can test your patch. I *think* it should work for him
> too but I don't know anything anymore. :-)
> 
> Thx.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

-- 
Ville Syrjälä
Intel