From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH] vfio, iommu: Fixed interaction of VFIO_IOMMU_MAP_DMA with IOMMU address limits Date: Fri, 1 Nov 2013 12:53:36 +0100 Message-ID: <20131101115336.GH17455@8bytes.org> References: <1377704672.10408.81.camel@ul30vt.home> <1381305832-2900-1-git-send-email-jsteckli@os.inf.tu-dresden.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1381305832-2900-1-git-send-email-jsteckli-IG//nw+yl+iQIjdd1DhZXWfrygkm6VTR@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Julian Stecklina Cc: David Woodhouse , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org 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 > Acked-by: Alex Williamson Applied, thanks.