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2023-06-19dma-mapping: force bouncing if the kmalloc() size is not cache-line-alignedCatalin Marinas
For direct DMA, if the size is small enough to have originated from a kmalloc() cache below ARCH_DMA_MINALIGN, check its alignment against dma_get_cache_alignment() and bounce if necessary. For larger sizes, it is the responsibility of the DMA API caller to ensure proper alignment. At this point, the kmalloc() caches are properly aligned but this will change in a subsequent patch. Architectures can opt in by selecting DMA_BOUNCE_UNALIGNED_KMALLOC. Link: https://lkml.kernel.org/r/20230612153201.554742-15-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jerry Snitselaar <jsnitsel@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Jonathan Cameron <jic23@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Mike Snitzer <snitzer@kernel.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Saravana Kannan <saravanak@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-26dma-direct: support PCI P2PDMA pages in dma-direct map_sgLogan Gunthorpe
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 <logang@deltatee.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-04-18dma-direct: use is_swiotlb_active in dma_direct_map_pageChristoph Hellwig
Use the more specific is_swiotlb_active check instead of checking the global swiotlb_force variable. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2022-04-14dma-direct: avoid redundant memory sync for swiotlbChao Gao
When we looked into FIO performance with swiotlb enabled in VM, we found swiotlb_bounce() is always called one more time than expected for each DMA read request. It turns out that the bounce buffer is copied to original DMA buffer twice after the completion of a DMA request (one is done by in dma_direct_sync_single_for_cpu(), the other by swiotlb_tbl_unmap_single()). But the content in bounce buffer actually doesn't change between the two rounds of copy. So, one round of copy is redundant. Pass DMA_ATTR_SKIP_CPU_SYNC flag to swiotlb_tbl_unmap_single() to skip the memory copy in it. This fix increases FIO 64KB sequential read throughput in a guest with swiotlb=force by 5.6%. Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code") Reported-by: Wang Zhaoyang1 <zhaoyang1.wang@intel.com> Reported-by: Gao Liang <liang.gao@intel.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-07-13swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncingClaire Chang
Propagate the swiotlb_force into io_tlb_default_mem->force_bounce and use it to determine whether to bounce the data or not. This will be useful later to allow for different pools. Signed-off-by: Claire Chang <tientzu@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Stefano Stabellini <sstabellini@kernel.org> Tested-by: Will Deacon <will@kernel.org> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v2: Includes Will's fix]
2021-07-13swiotlb: Update is_swiotlb_buffer to add a struct device argumentClaire Chang
Update is_swiotlb_buffer to add a struct device argument. This will be useful later to allow for different pools. Signed-off-by: Claire Chang <tientzu@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Stefano Stabellini <sstabellini@kernel.org> Tested-by: Will Deacon <will@kernel.org> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2021-03-17swiotlb: split swiotlb_tbl_sync_singleChristoph Hellwig
Split swiotlb_tbl_sync_single into two separate funtions for the to device and to cpu synchronization. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2021-03-17swiotlb: remove the alloc_size parameter to swiotlb_tbl_unmap_singleChristoph Hellwig
Now that swiotlb remembers the allocation size there is no need to pass it back to swiotlb_tbl_unmap_single. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2020-10-06dma-mapping: move large parts of <linux/dma-direct.h> to kernel/dmaChristoph Hellwig
Most of the dma_direct symbols should only be used by direct.c and mapping.c, so move them to kernel/dma. In fact more of dma-direct.h should eventually move, but that will require more coordination with other subsystems. Signed-off-by: Christoph Hellwig <hch@lst.de>