Re: [PATCH v2 08/16] iommu: introduce device fault data

[Jean-Philippe Brucker <jean-philippe.brucker@arm.com>]

On 13/11/17 16:57, Jacob Pan wrote:
> On Mon, 13 Nov 2017 13:06:24 +0000
> Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:
> 
>> On 10/11/17 22:18, Jacob Pan wrote:
>>> On Fri, 10 Nov 2017 13:54:59 +0000
>>> Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:
>>>   
>>>> On 09/11/17 19:36, Jacob Pan wrote:  
>>>>> On Tue, 7 Nov 2017 11:38:50 +0000
>>>>> Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:
>>>>>     
>>>>>> I think the IOMMU should pass the struct device associated to the
>>>>>> BDF to the fault handler. The fault handler can then deduce the
>>>>>> BDF from struct device if it needs to. This also allows to
>>>>>> support faults from non-PCI devices, where the BDF or deviceID
>>>>>> is specific to the IOMMU and doesn't mean anything to the device
>>>>>> driver. 
>>>>> Passing struct device is only useful if we use shared fault
>>>>> notification method, as I did in V1 patch with group level or
>>>>> current domain level.
>>>>>
>>>>> But the patch proposed here is a per device callback, there is no
>>>>> need for passing struct device since it is implied.    
>>>>
>>>> Sorry I had lost sight of the original patch in this thread. I
>>>> think the callback is fine as it is, in your patch:
>>>>
>>>> typedef int (*iommu_dev_fault_handler_t)(struct device *, struct
>>>> iommu_fault_event *);
>>>>  
>>> I should have removed struct device here also. thanks for pointing
>>> it out.  
>>
>> Why remove it? The device driver will use a single C function as fault
>> handler for multiple devices, so it needs struct device argument to
>> understand the context.
>>
> I meant to replace struct device * with just a void *, driver can
> register fault callback with instance of their private data, this could
> be a container struct of struct device.
> e.g.
> int iommu_register_device_fault_handler(struct device *dev,
> 				iommu_dev_fault_handler_t handler, void
> 				*data);
> 
> typedef int (*iommu_dev_fault_handler_t)(struct iommu_fault_event *, void *);

Ah I see. Yes that should work

Thanks,
Jean