Re: [PATCH for-4.16 v6] gnttab: allow setting max version per-domain

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Nov 08, 2021 at 02:46:39PM +0000, Ian Jackson wrote:
> Roger Pau Monné writes ("Re: [PATCH for-4.16 v6] gnttab: allow setting max 
> version per-domain"):
> >  Overall I think it's best to
> > express supported grant versions independently, and we might wish to
> > also allow to select a discrete set of grant versions that a domain
> > supports. IMO it might be sensible in the future if a new grant
> > version appears (v3), to select to expose grant v1 and v3 only to the
> > domain, and avoid v2. This would require some changes here, but we can
> > see about those when the time comes.
> 
> I'm not sure what layer we're talking about here.  The patch
> introduces a max version into the libxl api.  Is there any significant
> chance of a v3 (and hence, wanting to change the api) any time soon ?

I think it's unlikely, as it seems there's a trend to move data
transfer between domains from using shared memory to memory
duplication (ie: Argo).

It's also not clear to me whether anything similar to grants could be
made to work together with hardware memory encrypted VMs.

Thanks, Roger.