From fade1ec055dc6b6373e7487906b7899b41d0c46f Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 12 Sep 2016 17:14:00 +0100 Subject: [PATCH] iommu/dma: Avoid PCI host bridge windows With our DMA ops enabled for PCI devices, we should avoid allocating IOVAs which a host bridge might misinterpret as peer-to-peer DMA and lead to faults, corruption or other badness. To be safe, punch out holes for all of the relevant host bridge's windows when initialising a DMA domain for a PCI device. CC: Marek Szyprowski CC: Inki Dae Reported-by: Lorenzo Pieralisi Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- arch/arm64/mm/dma-mapping.c | 2 +- drivers/gpu/drm/exynos/exynos_drm_iommu.h | 2 +- drivers/iommu/dma-iommu.c | 25 ++++++++++++++++++++++- include/linux/dma-iommu.h | 3 ++- 4 files changed, 28 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index c4284c432ae8..610d8e53011e 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -827,7 +827,7 @@ static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops, * then the IOMMU core will have already configured a group for this * device, and allocated the default domain for that group. */ - if (!domain || iommu_dma_init_domain(domain, dma_base, size)) { + if (!domain || iommu_dma_init_domain(domain, dma_base, size, dev)) { pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", dev_name(dev)); return false; diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.h b/drivers/gpu/drm/exynos/exynos_drm_iommu.h index c8de4913fdbe..87f6b5672e11 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_iommu.h +++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.h @@ -66,7 +66,7 @@ static inline int __exynos_iommu_create_mapping(struct exynos_drm_private *priv, if (ret) goto free_domain; - ret = iommu_dma_init_domain(domain, start, size); + ret = iommu_dma_init_domain(domain, start, size, NULL); if (ret) goto put_cookie; diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 4329d18080cf..c5ab8667e6f2 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -103,18 +104,38 @@ void iommu_put_dma_cookie(struct iommu_domain *domain) } EXPORT_SYMBOL(iommu_put_dma_cookie); +static void iova_reserve_pci_windows(struct pci_dev *dev, + struct iova_domain *iovad) +{ + struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus); + struct resource_entry *window; + unsigned long lo, hi; + + resource_list_for_each_entry(window, &bridge->windows) { + if (resource_type(window->res) != IORESOURCE_MEM && + resource_type(window->res) != IORESOURCE_IO) + continue; + + lo = iova_pfn(iovad, window->res->start - window->offset); + hi = iova_pfn(iovad, window->res->end - window->offset); + reserve_iova(iovad, lo, hi); + } +} + /** * iommu_dma_init_domain - Initialise a DMA mapping domain * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() * @base: IOVA at which the mappable address space starts * @size: Size of IOVA space + * @dev: Device the domain is being initialised for * * @base and @size should be exact multiples of IOMMU page granularity to * avoid rounding surprises. If necessary, we reserve the page at address 0 * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but * any change which could make prior IOVAs invalid will fail. */ -int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size) +int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, + u64 size, struct device *dev) { struct iova_domain *iovad = cookie_iovad(domain); unsigned long order, base_pfn, end_pfn; @@ -152,6 +173,8 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size iovad->dma_32bit_pfn = end_pfn; } else { init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn); + if (dev && dev_is_pci(dev)) + iova_reserve_pci_windows(to_pci_dev(dev), iovad); } return 0; } diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h index 5ee806e41b5c..32c589062bd9 100644 --- a/include/linux/dma-iommu.h +++ b/include/linux/dma-iommu.h @@ -30,7 +30,8 @@ int iommu_get_dma_cookie(struct iommu_domain *domain); void iommu_put_dma_cookie(struct iommu_domain *domain); /* Setup call for arch DMA mapping code */ -int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size); +int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, + u64 size, struct device *dev); /* General helpers for DMA-API <-> IOMMU-API interaction */ int dma_direction_to_prot(enum dma_data_direction dir, bool coherent); -- 2.20.1