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

[Cornelia Huck]

On Fri, 4 Dec 2020 13:07:27 +0000
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:

> * Cornelia Huck (cohuck@redhat.com) wrote:
> > 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.  
> 
> There's already SEV-ES patches onlist for this on the SEV side.
> 
> <sigh on haggling over the name>
> 
> Perhaps 'confidential guest' is actually what we need, since the
> marketing folks seem to have started labelling this whole idea
> 'confidential computing'.

It's more like a 'possibly confidential guest', though.