Re: [Xen-devel] [PATCH v2 05/21] xen/arm: follow-up to allow DOM0 manage IRQ and MMIO

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 12/09/14 03:13, Ian Campbell wrote:
> On Thu, 2014-09-11 at 15:32 -0700, Julien Grall wrote:
> > The current solution doesn't map the device into DOM0 memory but the
> > device is still described in the device tree.
> I had some thoughts on that in the thread on the 00/21 mail BTW.
>
> > With the new property "xen,passthrough", we would have to remove the
> > node from DOM0, or teach DOM0 that the device should not be used.
> You would translate it into status="disabled" for dom0, that's all, no
> need to remove anything.
I didn't think about this. So this "xen.passthrough" property will be 
only used by Xen.
I will implement it for the next version.

> > Overall, I don't think dropping the node in DOM0 device tree will impact
> > it. If it's the case that would mean the device should not be
> > passthrough to another guest. So I will give a look to introduce this
> > new property. Shall I send a patch to the device tree bindings ML?
> >
> > BTW, I don't think the new property should be a boolean. Use only the
> > name should be enough here.
> That's what boolean means in DT context, a name without a value.
Oh right. I had in mind the status="disabled" stuff.

> >
> > > > +        {
> > > > +            res = route_irq_to_guest(d, irq, dt_node_name(dev));
> > > > +            if ( res )
> > > > +            {
> > > > +                printk(XENLOG_ERR "Unable to route IRQ %u to domain %u\n",
> > > > +                       irq, d->domain_id);
> > > > +                return res;
> > > > +            }
> > > > +        }
> > > >        }
> > > >
> > > > -    /* Map the address ranges */
> > > > +    /* Give permission and map MMIOs */
> > > Permissions are now given above, not below, aren't they?
> > Only permission for IRQ. The MMIO ones are given few lines below.
> Ah, right.
I can update the comment to make more clear.

Regards,

--
Julien Grall

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