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

[Julien Grall <julien.grall@linaro.org>]

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