Re: A proposal - binary

Andrew Morton
2006-08-04T05:54:21Z

On Fri, 04 Aug 2006 15:04:35 +1000
Rusty Russell <rusty@rustcorp.com.au> wrote:

> On Thu, 2006-08-03 at 21:18 -0700, Andrew Morton wrote:
> > > As far as LKML is concerned, the only interface which matters is the
> > > Linux -> <something> interface, which is defined within the scope of the
> > > Linux development process. That's what paravirt_ops is intended to be.
> >
> > I must confess that I still don't "get" paravirtops. AFACIT the VMI
> > proposal, if it works, will make that whole layer simply go away. Which
> > is attractive. If it works.
>
> Everywhere in the kernel where we have multiple implementations we want
> to select at runtime, we use an ops struct. Why should the choice of
> Xen/VMI/native/other be any different?

VMI is being proposed as an appropriate way to connect Linux to Xen. If
that is true then no other glue is needed.

The central point here is whether that is right.

> Yes, we could force native and Xen to work via VMI, but the result would
> be less clear, less maintainable, and gratuitously different from
> elsewhere in the kernel.

I suspect others would disagree with that. We're at the stage of needing
to see code to settle this.

> And, of course, unlike paravirt_ops where we
> can change and add ops at any time, we can't similarly change the VMI
> interface because it's an ABI (that's the point: the hypervisor can
> provide the implementation).

hm. Dunno. ABIs can be uprevved. Perhaps.