Commit 636e6572 authored by Leon Romanovsky's avatar Leon Romanovsky Committed by Marek Szyprowski
Browse files

iommu/dma: add support for DMA_ATTR_REQUIRE_COHERENT attribute 



Add support for the DMA_ATTR_REQUIRE_COHERENT attribute to the exported
functions. This attribute indicates that the SWIOTLB path must not be
used and that no sync operations should be performed.

Signed-off-by: default avatarLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260316-dma-debug-overlap-v3-6-1dde90a7f08b@nvidia.com
parent 2536617f

drivers/iommu/dma-iommu.c

+17 −4
Original line number Diff line number Diff line
@@ -1211,7 +1211,7 @@ dma_addr_t iommu_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size, 
	 */

	if (dev_use_swiotlb(dev, size, dir) &&

	    iova_unaligned(iovad, phys, size)) {

		if (attrs & DMA_ATTR_MMIO)

		if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT))

			return DMA_MAPPING_ERROR;



		phys = iommu_dma_map_swiotlb(dev, phys, size, dir, attrs);
@@ -1223,7 +1223,8 @@ dma_addr_t iommu_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size, 
		arch_sync_dma_for_device(phys, size, dir);



	iova = __iommu_dma_map(dev, phys, size, prot, dma_mask);

	if (iova == DMA_MAPPING_ERROR && !(attrs & DMA_ATTR_MMIO))

	if (iova == DMA_MAPPING_ERROR &&

	    !(attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT)))

		swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);

	return iova;

}
@@ -1233,7 +1234,7 @@ void iommu_dma_unmap_phys(struct device *dev, dma_addr_t dma_handle, 
{

	phys_addr_t phys;



	if (attrs & DMA_ATTR_MMIO) {

	if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT)) {

		__iommu_dma_unmap(dev, dma_handle, size);

		return;

	}
@@ -1945,9 +1946,21 @@ int dma_iova_link(struct device *dev, struct dma_iova_state *state, 
	if (WARN_ON_ONCE(iova_start_pad && offset > 0))

		return -EIO;



	/*

	 * DMA_IOVA_USE_SWIOTLB is set on state after some entry

	 * took SWIOTLB path, which we were supposed to prevent

	 * for DMA_ATTR_REQUIRE_COHERENT attribute.

	 */

	if (WARN_ON_ONCE((state->__size & DMA_IOVA_USE_SWIOTLB) &&

			 (attrs & DMA_ATTR_REQUIRE_COHERENT)))

		return -EOPNOTSUPP;



	if (!dev_is_dma_coherent(dev) && (attrs & DMA_ATTR_REQUIRE_COHERENT))

		return -EOPNOTSUPP;



	if (dev_use_swiotlb(dev, size, dir) &&

	    iova_unaligned(iovad, phys, size)) {

		if (attrs & DMA_ATTR_MMIO)

		if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT))

			return -EPERM;



		return iommu_dma_iova_link_swiotlb(dev, state, phys, offset,