From f02ad36d4f76645e7e1c21f572260e9a2e61c26b Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Fri, 8 Jul 2022 10:50:56 -0600 Subject: dma-direct: support PCI P2PDMA pages in dma-direct map_sg Add PCI P2PDMA support for dma_direct_map_sg() so that it can map PCI P2PDMA pages directly without a hack in the callers. This allows for heterogeneous SGLs that contain both P2PDMA and regular pages. A P2PDMA page may have three possible outcomes when being mapped: 1) If the data path between the two devices doesn't go through the root port, then it should be mapped with a PCI bus address 2) If the data path goes through the host bridge, it should be mapped normally, as though it were a CPU physical address 3) It is not possible for the two devices to communicate and thus the mapping operation should fail (and it will return -EREMOTEIO). SGL segments that contain PCI bus addresses are marked with sg_dma_mark_pci_p2pdma() and are ignored when unmapped. P2PDMA mappings are also failed if swiotlb needs to be used on the mapping. Signed-off-by: Logan Gunthorpe Reviewed-by: Christoph Hellwig Signed-off-by: Christoph Hellwig --- kernel/dma/direct.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'kernel/dma/direct.h') diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index a78c0ba70645..e38ffc5e6bdd 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -8,6 +8,7 @@ #define _KERNEL_DMA_DIRECT_H #include +#include int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, @@ -87,10 +88,15 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys); - if (is_swiotlb_force_bounce(dev)) + if (is_swiotlb_force_bounce(dev)) { + if (is_pci_p2pdma_page(page)) + return DMA_MAPPING_ERROR; return swiotlb_map(dev, phys, size, dir, attrs); + } if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + if (is_pci_p2pdma_page(page)) + return DMA_MAPPING_ERROR; if (is_swiotlb_active(dev)) return swiotlb_map(dev, phys, size, dir, attrs); -- cgit v1.2.3