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| author |   Robin Murphy <robin.murphy@arm.com> | 2017-01-16 13:24:55 +0000 |
|---|---|---|
| committer |   Joerg Roedel <jroedel@suse.de> | 2017-01-30 16:14:24 +0100 |
| commit | 122fac030e912ed723fe94d8eb0d5d0f6b31535e (patch) | |
| tree | ddfdbf1d6725f348ece0fffe7dc839077c32cc5a /drivers/iommu | |
| parent | iommu/dma: Stop getting dma_32bit_pfn wrong (diff) | |
| download | linux-dev-122fac030e912ed723fe94d8eb0d5d0f6b31535e.tar.xz linux-dev-122fac030e912ed723fe94d8eb0d5d0f6b31535e.zip | |
iommu/dma: Implement PCI allocation optimisation
Whilst PCI devices may have 64-bit DMA masks, they still benefit from
using 32-bit addresses wherever possible in order to avoid DAC (PCI) or
longer address packets (PCIe), which may incur a performance overhead.
Implement the same optimisation as other allocators by trying to get a
32-bit address first, only falling back to the full mask if that fails.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 6c6e70c56d88..1c9ac26e3b68 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -287,19 +287,28 @@ int dma_info_to_prot(enum dma_data_direction dir, bool coherent, } static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size, - dma_addr_t dma_limit) + dma_addr_t dma_limit, struct device *dev) { struct iova_domain *iovad = cookie_iovad(domain); unsigned long shift = iova_shift(iovad); unsigned long length = iova_align(iovad, size) >> shift; + struct iova *iova = NULL; if (domain->geometry.force_aperture) dma_limit = min(dma_limit, domain->geometry.aperture_end); + + /* Try to get PCI devices a SAC address */ + if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) + iova = alloc_iova(iovad, length, DMA_BIT_MASK(32) >> shift, + true); /* * Enforce size-alignment to be safe - there could perhaps be an * attribute to control this per-device, or at least per-domain... */ - return alloc_iova(iovad, length, dma_limit >> shift, true); + if (!iova) + iova = alloc_iova(iovad, length, dma_limit >> shift, true); + + return iova; } /* The IOVA allocator knows what we mapped, so just unmap whatever that was */ @@ -452,7 +461,7 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, if (!pages) return NULL; - iova = __alloc_iova(domain, size, dev->coherent_dma_mask); + iova = __alloc_iova(domain, size, dev->coherent_dma_mask, dev); if (!iova) goto out_free_pages; @@ -523,7 +532,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, struct iova_domain *iovad = cookie_iovad(domain); size_t iova_off = iova_offset(iovad, phys); size_t len = iova_align(iovad, size + iova_off); - struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev)); + struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev), dev); if (!iova) return DMA_ERROR_CODE; @@ -681,7 +690,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, prev = s; } - iova = __alloc_iova(domain, iova_len, dma_get_mask(dev)); + iova = __alloc_iova(domain, iova_len, dma_get_mask(dev), dev); if (!iova) goto out_restore_sg; @@ -761,7 +770,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, msi_page->phys = msi_addr; if (iovad) { - iova = __alloc_iova(domain, size, dma_get_mask(dev)); + iova = __alloc_iova(domain, size, dma_get_mask(dev), dev); if (!iova) goto out_free_page; msi_page->iova = iova_dma_addr(iovad, iova); |