From 2da274cdf998a1c12afa6b5975db2df1df01edf1 Mon Sep 17 00:00:00 2001 From: Zhen Lei Date: Thu, 20 Sep 2018 17:10:22 +0100 Subject: [PATCH] iommu/dma: Add support for non-strict mode With the flush queue infrastructure already abstracted into IOVA domains, hooking it up in iommu-dma is pretty simple. Since there is a degree of dependency on the IOMMU driver knowing what to do to play along, we key the whole thing off a domain attribute which will be set on default DMA ops domains to request non-strict invalidation. That way, drivers can indicate the appropriate support by acknowledging the attribute, and we can easily fall back to strict invalidation otherwise. The flush queue callback needs a handle on the iommu_domain which owns our cookie, so we have to add a pointer back to that, but neatly, that's also sufficient to indicate whether we're using a flush queue or not, and thus which way to release IOVAs. The only slight subtlety is switching __iommu_dma_unmap() from calling iommu_unmap() to explicit iommu_unmap_fast()/iommu_tlb_sync() so that we can elide the sync entirely in non-strict mode. Signed-off-by: Zhen Lei [rm: convert to domain attribute, tweak comments and commit message] Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- drivers/iommu/dma-iommu.c | 32 +++++++++++++++++++++++++++++++- include/linux/iommu.h | 1 + 2 files changed, 32 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 511ff9a1d6d9..cc1bf786cfac 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -55,6 +55,9 @@ struct iommu_dma_cookie { }; struct list_head msi_page_list; spinlock_t msi_lock; + + /* Domain for flush queue callback; NULL if flush queue not in use */ + struct iommu_domain *fq_domain; }; static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie) @@ -257,6 +260,20 @@ static int iova_reserve_iommu_regions(struct device *dev, return ret; } +static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad) +{ + struct iommu_dma_cookie *cookie; + struct iommu_domain *domain; + + cookie = container_of(iovad, struct iommu_dma_cookie, iovad); + domain = cookie->fq_domain; + /* + * The IOMMU driver supporting DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE + * implies that ops->flush_iotlb_all must be non-NULL. + */ + domain->ops->flush_iotlb_all(domain); +} + /** * iommu_dma_init_domain - Initialise a DMA mapping domain * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() @@ -275,6 +292,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; unsigned long order, base_pfn, end_pfn; + int attr; if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE) return -EINVAL; @@ -308,6 +326,13 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, } init_iova_domain(iovad, 1UL << order, base_pfn); + + if (!cookie->fq_domain && !iommu_domain_get_attr(domain, + DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) { + cookie->fq_domain = domain; + init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL); + } + if (!dev) return 0; @@ -393,6 +418,9 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie, /* The MSI case is only ever cleaning up its most recent allocation */ if (cookie->type == IOMMU_DMA_MSI_COOKIE) cookie->msi_iova -= size; + else if (cookie->fq_domain) /* non-strict mode */ + queue_iova(iovad, iova_pfn(iovad, iova), + size >> iova_shift(iovad), 0); else free_iova_fast(iovad, iova_pfn(iovad, iova), size >> iova_shift(iovad)); @@ -408,7 +436,9 @@ static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr, dma_addr -= iova_off; size = iova_align(iovad, size + iova_off); - WARN_ON(iommu_unmap(domain, dma_addr, size) != size); + WARN_ON(iommu_unmap_fast(domain, dma_addr, size) != size); + if (!cookie->fq_domain) + iommu_tlb_sync(domain); iommu_dma_free_iova(cookie, dma_addr, size); } diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 87994c265bf5..decabe8e8dbe 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -124,6 +124,7 @@ enum iommu_attr { DOMAIN_ATTR_FSL_PAMU_ENABLE, DOMAIN_ATTR_FSL_PAMUV1, DOMAIN_ATTR_NESTING, /* two stages of translation */ + DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, DOMAIN_ATTR_MAX, };