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

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

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).

> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

With that: Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel