Re: [Xen-devel] [PATCH v9 15/19] xen: create a Xen nexus to use in PV/PVH

On 01/07/2014 08:29 AM, Roger Pau Monné wrote:
> On 06/01/14 12:33, Julien Grall wrote:
>>
>>
>> On 01/06/2014 09:35 AM, Roger Pau Monné wrote:
>>> On 05/01/14 22:55, Julien Grall wrote:
>>>>
>>>>
>>>> On 01/02/2014 03:43 PM, Roger Pau Monne wrote:
>>>>> Introduce a Xen specific nexus that is going to be in charge for
>>>>> attaching Xen specific devices.
>>>>
>>>> Now that we have a xenpv bus, do we really need a specific nexus for
>>>> Xen?
>>>> We should be able to use the identify callback of xenpv to create the
>>>> bus.
>>>>
>>>> The other part of this patch can be merged in the patch #14 "Introduce
>>>> xenpv bus and a dummy pvcpu device".
>>>
>>> On x86 at least we need the Xen specific nexus, or we will fall back to
>>> use the legacy nexus which is not what we really want.
>>>
>>
>> Oh right, in any case can we use the identify callback of xenpv to add
>> the bus?
> 
> AFAICT this kind of bus devices don't have a identify routine, and they
> are usually added manually from the specific nexus, see acpi or legacy.
> Could you add the device on ARM when you detect that you are running as
> a Xen guest, or in the generic ARM nexus if Xen is detected?

Is there any reason to not add identify callback? If it's possible, I
would like to avoid as much as possible #ifdef XENHVM in ARM code.

-- 
Julien Grall