Re: [PATCH 2/5] iommu/amd: Implement DOMAIN_ATTR_GEOMETRY attribute

[Scott Wood]

On 01/19/2012 10:27 AM, Laurent Pinchart wrote:
> Hi Joerg,
> 
> On Thursday 19 January 2012 17:07:39 Joerg Roedel wrote:
>> On Thu, Jan 19, 2012 at 04:46:13PM +0100, Laurent Pinchart wrote:
>>>> +struct iommu_domain_geometry {
>>>> +	u64 aperture_start;	/* First address that can be mapped    */
>>>> +	u64 aperture_end;	/* Last address that can be mapped     */
>>>
>>> Would it make sense to use a platform-dependent type that represents
>>> physical addresses instead of u64 ?
>>
>> Well, u64 is a catch-all datatype which should suit all drivers. Is this
>> a problem at ARM?
> 
> No, it's not a problem for ARM, at least to my knowledge. It just struck me as 
> weird, as we have specific data types for other kinds of addresses (such as 
> dma_addr_t).

If we want to be able to expose these attribute structs to userspace via
vfio, we'll want to stick with fixed size types.

-Scott

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