[PATCH] iommu: Decouple iommu_map_sg from CPU page size
joro at 8bytes.org
Tue Dec 2 04:05:39 PST 2014
On Tue, Nov 25, 2014 at 05:50:55PM +0000, Robin Murphy wrote:
> If the IOMMU supports pages smaller than the CPU page size, segments
> which lie at offsets within the CPU page may be mapped based on the
> finer-grained IOMMU page boundaries. This minimises the amount of
> non-buffer memory between the CPU page boundary and the start of the
> segment which must be mapped and therefore exposed to the device, and
> brings the default iommu_map_sg implementation in line with
> iommu_map/unmap with respect to alignment.
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
> Hi Joerg,
> I noticed this whilst wiring up DMA mapping to this new API - on arm64
> we anticipate running 4k IOMMU pages with 64k CPU pages, in which case
> the alignment check ends up being unnecessarily strict.
Applied to the core branch, thanks.
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