| From f9423606ade08653dd8a43334f0a7fb45504c5cc Mon Sep 17 00:00:00 2001 |
| From: Julian Stecklina <jsteckli@os.inf.tu-dresden.de> |
| Date: Wed, 9 Oct 2013 10:03:52 +0200 |
| Subject: iommu/vt-d: Fixed interaction of VFIO_IOMMU_MAP_DMA with IOMMU address limits |
| |
| From: Julian Stecklina <jsteckli@os.inf.tu-dresden.de> |
| |
| commit f9423606ade08653dd8a43334f0a7fb45504c5cc upstream. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/iommu/intel-iommu.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/iommu/intel-iommu.c |
| +++ b/drivers/iommu/intel-iommu.c |
| @@ -782,7 +782,11 @@ static struct dma_pte *pfn_to_dma_pte(st |
| int offset; |
| |
| BUG_ON(!domain->pgd); |
| - BUG_ON(addr_width < BITS_PER_LONG && pfn >> addr_width); |
| + |
| + if (addr_width < BITS_PER_LONG && pfn >> addr_width) |
| + /* Address beyond IOMMU's addressing capabilities. */ |
| + return NULL; |
| + |
| parent = domain->pgd; |
| |
| while (level > 0) { |