From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Auger Subject: [PATCH v7 01/19] iommu/dma: Implement PCI allocation optimisation Date: Mon, 9 Jan 2017 13:45:52 +0000 Message-ID: <1483969570-3154-2-git-send-email-eric.auger@redhat.com> References: <1483969570-3154-1-git-send-email-eric.auger@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1483969570-3154-1-git-send-email-eric.auger-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: eric.auger-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, eric.auger.pro-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, marc.zyngier-5wv7dgnIgG8@public.gmane.org, robin.murphy-5wv7dgnIgG8@public.gmane.org, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: drjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, punit.agrawal-5wv7dgnIgG8@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, geethasowjanya.akula-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, pranav.sawargaonkar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, shankerd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, gpkulkarni-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org List-Id: iommu@lists.linux-foundation.org From: Robin Murphy 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 --- drivers/iommu/dma-iommu.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 2db0d64..a59ca47 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -204,19 +204,28 @@ int dma_direction_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 */ @@ -369,7 +378,7 @@ 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; @@ -440,7 +449,7 @@ 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; @@ -598,7 +607,7 @@ 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; @@ -675,7 +684,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, if (!msi_page) return NULL; - iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev)); + iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev), dev); if (!iova) goto out_free_page; -- 1.9.1