From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754748Ab3KALxl (ORCPT ); Fri, 1 Nov 2013 07:53:41 -0400 Received: from 8bytes.org ([85.214.48.195]:37988 "EHLO mail.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750980Ab3KALxj (ORCPT ); Fri, 1 Nov 2013 07:53:39 -0400 Date: Fri, 1 Nov 2013 12:53:36 +0100 From: Joerg Roedel To: Julian Stecklina Cc: David Woodhouse , Alex Williamson , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH] vfio, iommu: Fixed interaction of VFIO_IOMMU_MAP_DMA with IOMMU address limits 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-Disposition: inline In-Reply-To: <1381305832-2900-1-git-send-email-jsteckli@os.inf.tu-dresden.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-DSPAM-Result: Whitelisted X-DSPAM-Processed: Fri Nov 1 12:53:38 2013 X-DSPAM-Confidence: 0.9994 X-DSPAM-Probability: 0.0000 X-DSPAM-Signature: 5273964220861331913964 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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.