Hi, On 10/8/19 10:33 PM, Arvind Sankar wrote:
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.Fixes: 249baa547901 ("dma-mapping: provide a better default ->get_required_mask") Reported-by: Arvind Sankar <[email protected]> Tested-by: Arvind Sankar <[email protected]> Originally-by: Christoph Hellwig <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Fixed-by: Arvind Sankar <[email protected]> Signed-off-by: Arvind Sankar <[email protected]>
This patch looks good to me. Reviewed-by: Lu Baolu <[email protected]>
--- drivers/iommu/intel-iommu.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 3f974919d3bd..79e35b3180ac 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -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
