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iommu/vt-d: Return the correct dma mask when we are bypassing the IOMMU 

We must return a mask covering the full physical RAM when bypassing the
IOMMU mapping. Also, in iommu_need_mapping, we need to check using
dma_direct_get_required_mask to ensure that the device's dma_mask can
cover physical RAM before deciding to bypass IOMMU mapping.

Based on an earlier patch from Christoph Hellwig.

Fixes: 249baa5479 ("dma-mapping: provide a better default ->get_required_mask")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Arvind Sankar 2019-10-08 10:33:57 -04:00 committed by Christoph Hellwig
parent 0e2adab6cf
commit 9c24eaf81c
1 changed files with 9 additions and 1 deletions
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10
drivers/iommu/intel-iommu.c
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@ -3471,7 +3471,7 @@ static bool iommu_need_mapping(struct device *dev)
if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask)
dma_mask = dev->coherent_dma_mask;
if (dma_mask >= dma_get_required_mask(dev))
if (dma_mask >= dma_direct_get_required_mask(dev))
return false;
/*
@ -3775,6 +3775,13 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
return nelems;
}
static u64 intel_get_required_mask(struct device *dev)
{
if (!iommu_need_mapping(dev))
return dma_direct_get_required_mask(dev);
return DMA_BIT_MASK(32);
}
static const struct dma_map_ops intel_dma_ops = {
.alloc = intel_alloc_coherent,
.free = intel_free_coherent,
@ -3787,6 +3794,7 @@ static const struct dma_map_ops intel_dma_ops = {
.dma_supported = dma_direct_supported,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
.get_required_mask = intel_get_required_mask,
};
static void