Re: [PATCH v2 01/15] xen/arm: register mmio handler at runtime

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

On 04/08/2014 07:35 AM, Vijay Kilari wrote:
> On Fri, Apr 4, 2014 at 8:57 PM, Julien Grall <julien.grall@linaro.org> wrote:
>> On 04/04/2014 04:24 PM, Vijay Kilari wrote:
>>
>>>>> As I said on the previous version, it would be nice to remove check
>>>>> callback in the mmio_handler and replace it by addr/size. It's better if
>>>>> we might want to change the place in the memory following the guest.
>>>>>
>>>>> So the result function would be:
>>>>>
>>>>> register_mmio_handler(struct domain *d, read_t read, write_t write,
>>>>> addr, size);
>>>>>
>>>> OK.
>>>    Though you suggested, I kept this check handler because it gives flexibility
>>> for driver to make additional checks if required apart from just checking for
>>> address range.
>>
>> What kind of checks? If the handler is registered to a domain that means
>> we want to use it, right? It would seem strange to trap once a while.
> 
>    IMO, with check handler it will give more flexibility for driver to
> various kinds of checks.
> Ex: Driver wants to check for multiple addr ranges etc.,

>From driver POV it's easier to have one range by set of callbacks rather
than multiple range.
Because you will end up to check in 2 place the address (once in check
and once in read/write callback).

You don't use this feature in your code and I don't think it will be
use, so I would prefer to get a rid of check and let handle_mmio do the
job for us.

Regards,

-- 
Julien Grall