From: Mario Limonciello Date: Mon, 4 Apr 2022 20:47:23 +0000 (-0500) Subject: dma-iommu: Check that swiotlb is active before trying to use it X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f316ba0a8814f4c91e80a435da3421baf0ddd24c;p=linux.git dma-iommu: Check that swiotlb is active before trying to use it If the IOMMU is in use and an untrusted device is connected to an external facing port but the address requested isn't page aligned will cause the kernel to attempt to use bounce buffers. If for some reason the bounce buffers have not been allocated this is a problem that should be made apparent to the user. Signed-off-by: Mario Limonciello Reviewed-by: Robin Murphy Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220404204723.9767-3-mario.limonciello@amd.com Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 09f6e1c0f9c07..1ca85d37eeab2 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -971,6 +971,11 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, void *padding_start; size_t padding_size, aligned_size; + if (!is_swiotlb_active(dev)) { + dev_warn_once(dev, "DMA bounce buffers are inactive, unable to map unaligned transaction.\n"); + return DMA_MAPPING_ERROR; + } + aligned_size = iova_align(iovad, size); phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size, iova_mask(iovad), dir, attrs);