Re: [RFCv2 15/16] KVM: Unmap protected pages from direct mapping

From: David Hildenbrand
Date: Tue Oct 20 2020 - 08:18:57 EST


On 20.10.20 08:18, Kirill A. Shutemov wrote:
> If the protected memory feature enabled, unmap guest memory from
> kernel's direct mappings.

Gah, ugly. I guess this also defeats compaction, swapping, ... oh gosh.
As if all of the encrypted VM implementations didn't bring us enough
ugliness already (SEV extensions also don't support reboots, but can at
least kexec() IIRC).

Something similar is done with secretmem [1]. And people don't seem to
like fragmenting the direct mapping (including me).

[1] https://lkml.kernel.org/r/20200924132904.1391-1-rppt@xxxxxxxxxx

--
Thanks,

David / dhildenb