On Tue, Nov 24, 2020, Vipin Sharma wrote:
> On Tue, Nov 24, 2020 at 12:18:45PM -0800, David Rientjes wrote:
> > On Tue, 24 Nov 2020, Vipin Sharma wrote:
> >
> > > > > Looping Janosch and Christian back into the thread.
> > > > >
> > > > >
> > > > >
> > > > > I interpret this suggestion as
> > > > >
> > > > > encryption.{sev,sev_es,keyids}.{max,current,events} for AMD and Intel
> > > > >
> > > >
> > > > I think it makes sense to use encryption_ids instead of simply
> > > > encryption, that
> > > > way it's clear the cgroup is accounting ids as opposed to restricting
> > > > what
> > > > techs can be used on yes/no basis.
> > > >
> >
> > Agreed.
> >
> > > > > offerings, which was my thought on this as well.
> > > > >
> > > > >
> > > > >
> > > > > Certainly the kernel could provide a single interface for all of
> > > > > these and
> > > > > key value pairs depending on the underlying encryption technology but
> > > > > it
> > > > > seems to only introduce additional complexity in the kernel in string
> > > > >
> > > > > parsing that can otherwise be avoided. I think we all agree that a
> > > > > single
> > > > > interface for all encryption keys or one-value-per-file could be done
> > > > > in
> > > > > the kernel and handled by any userspace agent that is configuring
> > > > > these
> > > > > values.
> > > > >
> > > > >
> > > > >
> > > > > I think Vipin is adding a root level file that describes how many
> > > > > keys we
> > > > > have available on the platform for each technology. So I think this
> > > > > comes
> > > > > down to, for example, a single encryption.max file vs
> > > > >
> > > > > encryption.{sev,sev_es,keyid}.max. SEV and SEV-ES ASIDs are
> > > > > provisioned
> > > >
> > > > Are you suggesting that the cgroup omit "current" and "events"? I
> > > > agree there's
> > > > no need to enumerate platform total, but not knowing how many of the
> > > > allowed IDs
> > > > have been allocated seems problematic.
> > > >
> > >
> > > We will be showing encryption_ids.{sev,sev_es}.{max,current}
> > > I am inclined to not provide "events" as I am not using it, let me know
> > > if this file is required, I can provide it then.
I've no objection to omitting current until it's needed.
> > > I will provide an encryption_ids.{sev,sev_es}.stat file, which shows
> > > total available ids on the platform. This one will be useful for
> > > scheduling jobs in the cloud infrastructure based on total supported
> > > capacity.
> > >
> >
> > Makes sense. I assume the stat file is only at the cgroup root level
> > since it would otherwise be duplicating its contents in every cgroup under
> > it. Probably not very helpful for child cgroup to see stat = 509 ASIDs
> > but max = 100 :)
>
> Yes, only at root.
Is a root level stat file needed? Can't the infrastructure do .max - .current
on the root cgroup to calculate the number of available ids in the system?
