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iommu/dma: add support for DMA_ATTR_REQUIRE_COHERENT attribute

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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: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260316-dma-debug-overlap-v3-6-1dde90a7f08b@nvidia.com
This commit is contained in:
Leon Romanovsky 2026-03-16 21:06:50 +02:00 committed by Marek Szyprowski
parent 2536617f20
commit 636e6572e8
1 changed files with 17 additions and 4 deletions
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21
drivers/iommu/dma-iommu.c
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@ -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,