Re: [for-6.0 v5 00/13] Generalize memory encryption models

[Cornelia Huck]

On Fri, 4 Dec 2020 09:06:50 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> On 04.12.20 06:44, David Gibson wrote:
> > A number of hardware platforms are implementing mechanisms whereby the
> > hypervisor does not have unfettered access to guest memory, in order
> > to mitigate the security impact of a compromised hypervisor.
> > 
> > AMD's SEV implements this with in-cpu memory encryption, and Intel has
> > its own memory encryption mechanism.  POWER has an upcoming mechanism
> > to accomplish this in a different way, using a new memory protection
> > level plus a small trusted ultravisor.  s390 also has a protected
> > execution environment.
> > 
> > The current code (committed or draft) for these features has each
> > platform's version configured entirely differently.  That doesn't seem
> > ideal for users, or particularly for management layers.
> > 
> > AMD SEV introduces a notionally generic machine option
> > "machine-encryption", but it doesn't actually cover any cases other
> > than SEV.
> > 
> > This series is a proposal to at least partially unify configuration
> > for these mechanisms, by renaming and generalizing AMD's
> > "memory-encryption" property.  It is replaced by a
> > "securable-guest-memory" property pointing to a platform specific  
> 
> Can we do "securable-guest" ?
> s390x also protects registers and integrity. memory is only one piece
> of the puzzle and what we protect might differ from platform to 
> platform.
> 

I agree. Even technologies that currently only do memory encryption may
be enhanced with more protections later.