iommu/vt-d: Fixed interaction of VFIO_IOMMU_MAP_DMA with IOMMU address limits
The BUG_ON in drivers/iommu/intel-iommu.c:785 can be triggered from userspace via VFIO by calling the VFIO_IOMMU_MAP_DMA ioctl on a vfio device with any address beyond the addressing capabilities of the IOMMU. The problem is that the ioctl code calls iommu_iova_to_phys before it calls iommu_map. iommu_map handles the case that it gets addresses beyond the addressing capabilities of its IOMMU. intel_iommu_iova_to_phys does not. This patch fixes iommu_iova_to_phys to return NULL for addresses beyond what the IOMMU can handle. This in turn causes the ioctl call to fail in iommu_map and (correctly) return EFAULT to the user with a helpful warning message in the kernel log. Signed-off-by: Julian Stecklina <jsteckli@os.inf.tu-dresden.de> Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Joerg Roedel <joro@8bytes.org>
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