Re: [PATCH] vfio, iommu: Fixed interaction of VFIO_IOMMU_MAP_DMAwith IOMMU address limits

From: Joerg Roedel
Date: Fri Nov 01 2013 - 07:53:45 EST


On Wed, Oct 09, 2013 at 10:03:52AM +0200, Julian Stecklina wrote:
> 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@xxxxxxxxxxxxxxxxxxxx>
> Acked-by: Alex Williamson <alex.williamson@xxxxxxxxxx>

Applied, thanks.

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