Re: [RFC PATCH 3/3] x86/microcode: Taint and warn on late loading

From: Borislav Petkov
Date: Wed May 25 2022 - 03:37:39 EST


On Wed, May 25, 2022 at 08:59:40AM +0200, Peter Zijlstra wrote:
> On Tue, May 24, 2022 at 06:03:04PM -0700, Luck, Tony wrote:
> > On Tue, May 24, 2022 at 08:53:24PM +0200, Borislav Petkov wrote:
> > > + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
> >
> > Seems harsh. Updating microcode to the latest is arguably the
> > way to make sure that your CPU stays "IN_SPEC" (since the microcode
> > may have a fix for a functional issue).
>
> Then use early loading. There's too many fails associated with late
> loading.

Yes, short of

TAINT_YOU_DID_SOMETHING_DANGEROUS

we simply don't have a better taint flag.

--
Regards/Gruss,
Boris.

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