Re: SEV guest regression in 4.18

From: Borislav Petkov
Date: Sat Aug 25 2018 - 00:48:30 EST


On Fri, Aug 24, 2018 at 01:47:10PM -0500, Brijesh Singh wrote:
> I am more inclined towards creating a new section with PMD aligned and
> sized. This section will contains the decrypted data. In early
> boot code we will update the mapping with C=0. If caller wants to create
> a shared variable then it can do so with:
>
> static int foo __decrypted;

Right, and keeping the SEV-ES's GHCB in mind, you could make that
section extensible so that the GHCB's 4K page can land there too. Maybe
something like a PMD-aligned range of 4K pages which are fully defined
and which hypervisor and guest can share and can be used for all kinds of
communication in the future...

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Regards/Gruss,
Boris.

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