Commit ec818cae authored by Leon Romanovsky's avatar Leon Romanovsky Committed by Marek Szyprowski
Browse files

mm/hmm: properly take MMIO path 



In case peer-to-peer transaction traverses through host bridge,
the IOMMU needs to have IOMMU_MMIO flag, together with skip of
CPU sync.

The latter was handled by provided DMA_ATTR_SKIP_CPU_SYNC flag,
but IOMMU flag was missed, due to assumption that such memory
can be treated as regular one.

Reuse newly introduced DMA attribute to properly take MMIO path.

Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
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/998251caf3f9d1a3f6f8205f1f494c707fb4d8fa.1757423202.git.leonro@nvidia.com
parent e1d69da2

mm/hmm.c

+8 −7
Original line number Diff line number Diff line
@@ -746,7 +746,7 @@ dma_addr_t hmm_dma_map_pfn(struct device *dev, struct hmm_dma_map *map, 
	case PCI_P2PDMA_MAP_NONE:

		break;

	case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:

		attrs |= DMA_ATTR_SKIP_CPU_SYNC;

		attrs |= DMA_ATTR_MMIO;

		pfns[idx] |= HMM_PFN_P2PDMA;

		break;

	case PCI_P2PDMA_MAP_BUS_ADDR:
@@ -776,7 +776,7 @@ dma_addr_t hmm_dma_map_pfn(struct device *dev, struct hmm_dma_map *map, 
			goto error;



		dma_addr = dma_map_phys(dev, paddr, map->dma_entry_size,

					DMA_BIDIRECTIONAL, 0);

					DMA_BIDIRECTIONAL, attrs);

		if (dma_mapping_error(dev, dma_addr))

			goto error;
@@ -811,16 +811,17 @@ bool hmm_dma_unmap_pfn(struct device *dev, struct hmm_dma_map *map, size_t idx) 
	if ((pfns[idx] & valid_dma) != valid_dma)

		return false;



	if (pfns[idx] & HMM_PFN_P2PDMA)

		attrs |= DMA_ATTR_MMIO;



	if (pfns[idx] & HMM_PFN_P2PDMA_BUS)

		; /* no need to unmap bus address P2P mappings */

	else if (dma_use_iova(state)) {

		if (pfns[idx] & HMM_PFN_P2PDMA)

			attrs |= DMA_ATTR_SKIP_CPU_SYNC;

	else if (dma_use_iova(state))

		dma_iova_unlink(dev, state, idx * map->dma_entry_size,

				map->dma_entry_size, DMA_BIDIRECTIONAL, attrs);

	} else if (dma_need_unmap(dev))

	else if (dma_need_unmap(dev))

		dma_unmap_phys(dev, dma_addrs[idx], map->dma_entry_size,

			       DMA_BIDIRECTIONAL, 0);

			       DMA_BIDIRECTIONAL, attrs);



	pfns[idx] &=

		~(HMM_PFN_DMA_MAPPED | HMM_PFN_P2PDMA | HMM_PFN_P2PDMA_BUS);