Messages in this thread | | | Date | Thu, 7 Apr 2022 14:07:21 +0100 | Subject | Re: [PATCH v2 2/2] dma-iommu: Check that swiotlb is active before trying to use it | From | Robin Murphy <> |
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On 2022-04-04 21:47, Mario Limonciello via iommu wrote: > 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.
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> > --- > v1->v2: > * Move error message into the caller > > drivers/iommu/dma-iommu.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 09f6e1c0f9c0..1ca85d37eeab 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);
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