Re: [PATCH] x86/nospec: Unwreck the RSB stuffing

From: Borislav Petkov
Date: Tue Aug 16 2022 - 09:03:34 EST


On Tue, Aug 16, 2022 at 12:52:58PM +0000, Andrew Cooper wrote:
> One minor point.  Stuff 32 slots.
>
> There are Intel parts out in the world with RSBs larger than 32 entries,
> and this loop does not fill the entire RSB on those.
>
> This is why the 32-entry stuffing loop is explicitly not supported on
> eIBRS hardware as a general mechanism.

I'm guessing there will be an Intel patch forthcoming, making that
RSB_CLEAR_LOOPS more dynamic, based on the current model.

:-)

--
Regards/Gruss,
Boris.

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