Re: [PATCH v5 29/32] x86/mm: Add support to encrypt the kernel in-place

Borislav Petkov
2017-05-26T16:25:37Z

On Thu, May 25, 2017 at 05:24:27PM -0500, Tom Lendacky wrote:
> I guess I could do that, but this will probably only end up clearing a
> single PGD entry anyway since it's highly doubtful the address range
> would cross a 512GB boundary.

Or you can compute how many 512G-covering, i.e., PGD entries there are
and clear just the right amnount. :^)

> I can change the name. As for the use of ENTRY... without the
> ENTRY/ENDPROC combination I was receiving a warning about a return
> instruction outside of a callable function. It looks like I can just
> define the "sme_enc_routine:" label with the ENDPROC and the warning
> goes away and the global is avoided. It doesn't like the local labels
> (.L...) so I'll use the new name.

Is that warning from objtool or where does it come from?

How do I trigger it locally?

> The hardware will try to optimize rep movsb into large chunks assuming
> things are aligned, sizes are large enough, etc. so we don't have to
> explicitly specify and setup for a rep movsq.

I thought the hw does that for movsq too?

--
Regards/Gruss,
Boris.

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