linux-kernel - [PATCH 4.4 159/312] iommu/dma: Respect IOMMU aperture when allocating

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Date:   Fri,  8 May 2020 14:32:30 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 4.4 159/312] iommu/dma: Respect IOMMU aperture when allocating

From: Robin Murphy <robin.murphy@....com>

commit c987ff0d3cb37d7fe1ddaa370811dfd9f73643fa upstream.

Where a device driver has set a 64-bit DMA mask to indicate the absence
of addressing limitations, we still need to ensure that we don't
allocate IOVAs beyond the actual input size of the IOMMU. The reported
aperture is the most reliable way we have of inferring that input
address size, so use that to enforce a hard upper limit where available.

Fixes: 0db2e5d18f76 ("iommu: Implement common IOMMU ops for DMA mapping")
Signed-off-by: Robin Murphy <robin.murphy@....com>
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/iommu/dma-iommu.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -152,12 +152,15 @@ int dma_direction_to_prot(enum dma_data_
 	}
 }
 
-static struct iova *__alloc_iova(struct iova_domain *iovad, size_t size,
+static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size,
 		dma_addr_t dma_limit)
 {
+	struct iova_domain *iovad = domain->iova_cookie;
 	unsigned long shift = iova_shift(iovad);
 	unsigned long length = iova_align(iovad, size) >> shift;
 
+	if (domain->geometry.force_aperture)
+		dma_limit = min(dma_limit, domain->geometry.aperture_end);
 	/*
 	 * Enforce size-alignment to be safe - there could perhaps be an
 	 * attribute to control this per-device, or at least per-domain...
@@ -297,7 +300,7 @@ struct page **iommu_dma_alloc(struct dev
 	if (!pages)
 		return NULL;
 
-	iova = __alloc_iova(iovad, size, dev->coherent_dma_mask);
+	iova = __alloc_iova(domain, size, dev->coherent_dma_mask);
 	if (!iova)
 		goto out_free_pages;
 
@@ -369,7 +372,7 @@ dma_addr_t iommu_dma_map_page(struct dev
 	phys_addr_t phys = page_to_phys(page) + offset;
 	size_t iova_off = iova_offset(iovad, phys);
 	size_t len = iova_align(iovad, size + iova_off);
-	struct iova *iova = __alloc_iova(iovad, len, dma_get_mask(dev));
+	struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev));
 
 	if (!iova)
 		return DMA_ERROR_CODE;
@@ -483,7 +486,7 @@ int iommu_dma_map_sg(struct device *dev,
 		prev = s;
 	}
 
-	iova = __alloc_iova(iovad, iova_len, dma_get_mask(dev));
+	iova = __alloc_iova(domain, iova_len, dma_get_mask(dev));
 	if (!iova)
 		goto out_restore_sg;