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Re: [Xen-API] New API Document and C Bindings

On Fri, Sep 15, 2006 at 02:08:36AM +0100, John Levon wrote:
> On Fri, Sep 15, 2006 at 01:50:54AM +0100, Daniel P. Berrange wrote:
> > > In that case I would suggest introducing a privileged flag for the VM 
> > > classes. Maybe that ends up being a distinguishing factor between VMs 
> > > like 
> > > dom-0, driver domains and other guests.
> > 
> > Except that its not really representative of what's going on - it implies
> > a discrete set of privilege levels can be assigned to domains. Domains
> More generally it sounds like their needs to be two classes, one a sub-class 
> of
> the other. Certain things (vcpu pinnings, resource utilisation data) belong in
> the superclass, other stuff in the other. Certainly the API would need to 
> allow
> people to identify what /kind/ of domain a particular representation is.

I'm still not convinced that there's any particularly useful classification
of different domains. Each domain has a varying & overlapping set of 
capabilities which can't easily be put into a strict hierarchy. Thus I
think it would be more useful to keep a flat classification of all domains,
and instead explicitly attach a set of capability flags to each domain. Apps
aren't really concerned with is this Domain type X, or Y - they are concerned
with what capabilities type X or Y has. Attaching capabilities directly to
individual domains is much more flexible than infering capabilities from
a 'type' approximation.

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