Re: [PATCH Part2 v5 00/45] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support

Joerg Roedel
2021-11-16T13:30:25Z

On Mon, Nov 15, 2021 at 07:15:07PM +0000, Sean Christopherson wrote:
> It creates a new attack surface, e.g. if the guest mishandles the #VC and does
> PVALIDATE on memory that it previously accepted, then userspace can attack the
> guest by accessing guest private memory to coerce the guest into consuming corrupted
> data.

If a guest can be tricked into a double PVALIDATE or otherwise
misbehaves on a #VC exception, then it is a guest bug and needs to be
fixed there.

It is a core requirement to the #VC handler that it can not be tricked
that way.

Regards,

--
Jörg Rödel
jroedel@suse.de

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