Re: [PATCH v3 3/3] xen/arm: introduce XENFEAT_grant_map_identity

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

On 07/24/2014 03:43 PM, Jan Beulich wrote:
>>>> On 24.07.14 at 16:10, <stefano.stabellini@eu.citrix.com> wrote:
>> On Thu, 24 Jul 2014, Jan Beulich wrote:
>>>>>> On 24.07.14 at 15:31, <stefano.stabellini@eu.citrix.com> wrote:
>>>> --- a/xen/common/grant_table.c
>>>> +++ b/xen/common/grant_table.c
>>>> @@ -727,7 +727,7 @@ __gnttab_map_grant_ref(
>>>>  
>>>>      double_gt_lock(lgt, rgt);
>>>>  
>>>> -    if ( gnttab_need_iommu_mapping(ld) )
>>>> +    if ( gnttab_need_iommu_mapping(ld) || gnttab_need_identity_mapping(ld) 
>> )
>>>
>>> As before I think this change is pointless.
>>
>> I don't understand how you propose to solve the problem.
> 
> I think ARM's gnttab_need_iommu_mapping() needs to just be
> is_domain_direct_mapped() then.

So ARM people will think we need an iommu to add the identity mapping.
Why don't we rename gnttab_need_iommu_mapping into
gnttab_need_identity_mapping?

It would less confusing for both x86 and ARM.

Regards,

-- 
Julien Grall