Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation

From: Woodhouse, David
Date: Tue Jan 23 2018 - 18:19:31 EST


On Tue, 2018-01-23 at 14:49 -0800, Andi Kleen wrote:
> > Not sure. Maybe to start, the answer might be to allow it to be set for
> > the ultra-paranoid, but in general don't enable it by default. Having it
> > enabled would be an alternative to someone deciding to disable SMT, since
> > that would have even more of a performance impact.
>
> I agree. A reasonable strategy would be to only enable it for
> processes that have dumpable disabled. This should be already set for
> high value processes like GPG, and allows others to opt-in if
> they need to.

That seems to make sense, and I think was the solution we were
approaching for IBPB on context switch too, right?

Are we generally agreed on dumpable as the criterion for both of those?

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