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iommu/dma: Respect bus DMA limit for IOVAs

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Take the new bus limit into account (when present) for IOVA allocations,
to accommodate those SoCs which integrate off-the-shelf IP blocks with
narrower interconnects such that the link between a device output and an
IOMMU input can truncate DMA addresses to even fewer bits than the
native size of either block's interface would imply.

Eventually it might make sense for the DMA core to apply this constraint
up-front in dma_set_mask() and friends, but for now this seems like the
least risky approach.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Robin Murphy 2018-07-23 23:16:10 +01:00 committed by Christoph Hellwig
parent 6c2fb2ea76
commit 03bfdc3117
1 changed files with 3 additions and 0 deletions
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3
drivers/iommu/dma-iommu.c
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@ -367,6 +367,9 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
iova_len = roundup_pow_of_two(iova_len);
if (dev->bus_dma_mask)
dma_limit &= dev->bus_dma_mask;
if (domain->geometry.force_aperture)
dma_limit = min(dma_limit, domain->geometry.aperture_end);