From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: RFC: IOMMU/AMD: Error Handling Date: Tue, 30 Apr 2013 17:21:43 +0200 Message-ID: <20130430152143.GB25163@8bytes.org> References: <517ECDDA.3000606@amd.com> <517ED3A9.2050508@redhat.com> <517EE940.8010005@redhat.com> <517FDB96.7060602@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <517FDB96.7060602-5C7GfCeVMHo@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: Suravee Suthikulanit Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: iommu@lists.linux-foundation.org On Tue, Apr 30, 2013 at 09:56:22AM -0500, Suthikulpanit, Suravee wrote: > This sounds more like issue with the order of how things are > initialized in the system. No, the problem is that almost all BIOS-provided IVRS tables are buggy because they do not define a unity-mapped region for devices that need one (like USB controllers). So there is a time window from iommu driver initialization to where the usb driver takes over the controller where these io-page-faults can happen. Joerg From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760885Ab3D3PVw (ORCPT ); Tue, 30 Apr 2013 11:21:52 -0400 Received: from 8bytes.org ([85.214.48.195]:35235 "EHLO mail.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760836Ab3D3PVq (ORCPT ); Tue, 30 Apr 2013 11:21:46 -0400 Date: Tue, 30 Apr 2013 17:21:43 +0200 From: Joerg Roedel To: Suravee Suthikulanit Cc: Don Dutile , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: RFC: IOMMU/AMD: Error Handling Message-ID: <20130430152143.GB25163@8bytes.org> References: <517ECDDA.3000606@amd.com> <517ED3A9.2050508@redhat.com> <517EE940.8010005@redhat.com> <517FDB96.7060602@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <517FDB96.7060602@amd.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-DSPAM-Result: Whitelisted X-DSPAM-Processed: Tue Apr 30 17:21:44 2013 X-DSPAM-Confidence: 0.9985 X-DSPAM-Probability: 0.0000 X-DSPAM-Signature: 517fe18823671358478724 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 30, 2013 at 09:56:22AM -0500, Suthikulpanit, Suravee wrote: > This sounds more like issue with the order of how things are > initialized in the system. No, the problem is that almost all BIOS-provided IVRS tables are buggy because they do not define a unity-mapped region for devices that need one (like USB controllers). So there is a time window from iommu driver initialization to where the usb driver takes over the controller where these io-page-faults can happen. Joerg