Re: [Xen-devel] [PATCH v4 19/21] xen/arm: grant: Add another entry to map MFN 1:1 in dom0 p2m

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 04/28/2014 03:11 PM, Ian Campbell wrote:
> On Tue, 2014-04-22 at 14:14 +0100, Julien Grall wrote:
>> Grant mapping can be used for DMA request. The dev_bus_addr returned by the
>> hypercall is the MFN (not the IPA). Currently Linux is using this address 
>> (via
>> swiotlb) to program the DMA.
>> When the device is protected by IOMMU the request will fail. We have to
>> add 1:1 mapping in the domain p2m to allow DMA request working.
>>
>> This is valid because DOM0 has its memory mapped 1:1.
> Go on to say:
> 
> ... and therefore we know that RAM and devices cannot clash (or
> something).

Your sentence sounds good. I will update the commit message with it.

>> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> 
> With that: Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

Thanks!

-- 
Julien Grall

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