[PATCH] iommu/dma-iommu: properly respect configured address space size

Marek Szyprowski m.szyprowski at samsung.com
Mon Nov 7 05:06:13 PST 2016

When one called iommu_dma_init_domain() with size smaller than device's
DMA mask, the alloc_iova() will not respect it and always assume that all
IOVA addresses will be allocated from the the (base ... dev->dma_mask) range.

This patch fixes this issue by taking the configured address space size
parameter into account (if it is smaller than the device's dma_mask).

Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
 drivers/iommu/dma-iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index c5ab8667e6f2..8b4b72654359 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -212,11 +212,13 @@ static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size,
 	if (domain->geometry.force_aperture)
 		dma_limit = min(dma_limit, domain->geometry.aperture_end);
+	dma_limit = min(dma_limit >> shift, (dma_addr_t)iovad->dma_32bit_pfn);
 	 * Enforce size-alignment to be safe - there could perhaps be an
 	 * attribute to control this per-device, or at least per-domain...
-	return alloc_iova(iovad, length, dma_limit >> shift, true);
+	return alloc_iova(iovad, length, dma_limit, true);
 /* The IOVA allocator knows what we mapped, so just unmap whatever that was */

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