Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756695Ab3GKU7E (ORCPT ); Thu, 11 Jul 2013 16:59:04 -0400 Received: from mail-pb0-f41.google.com ([209.85.160.41]:53223 "EHLO mail-pb0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756624Ab3GKU7C (ORCPT ); Thu, 11 Jul 2013 16:59:02 -0400 Date: Thu, 11 Jul 2013 13:59:02 -0700 From: Guenter Roeck To: Chris Wright Cc: Bjorn Helgaas , David Woodhouse , "linux-kernel@vger.kernel.org" , "open list:INTEL IOMMU (VT-d)" Subject: Re: WARNING: at drivers/iommu/dmar.c:484 warn_invalid_dmar with Intel Motherboard Message-ID: <20130711205902.GB22605@roeck-us.net> References: <20130709202406.GA11867@roeck-us.net> <20130709223106.GA16429@roeck-us.net> <20130709232252.GB2676@sequoia2.sous-sol.org> <20130709234331.GA10833@roeck-us.net> <20130711190054.GC24833@sequoia2.sous-sol.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130711190054.GC24833@sequoia2.sous-sol.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1769 Lines: 35 On Thu, Jul 11, 2013 at 12:00:54PM -0700, Chris Wright wrote: > * Guenter Roeck (linux@roeck-us.net) wrote: > > On Tue, Jul 09, 2013 at 04:22:52PM -0700, Chris Wright wrote: > > > One thing I've seen is the BIOS zeroing the base register address when > > > VT-d is disabled in BIOS. So, Guenter, a "fix" may be simply enabling > > > VT-d in the BIOS. > > > > > Ah, yes, I think I may have that disabled. I'll check it tonight. > > Did you find out if BIOS change fixed this? > No, it didn't. Enabling or disabling virtualization in the BIOS did not make a difference. It looks like there is a bad DMAR table entry (with address 0) in the ACPI data. In case you are interested how it looks like: DMAR @ 0xcb3f3f90 0000: 44 4d 41 52 90 00 00 00 01 d5 49 4e 54 45 4c 20 DMAR......INTEL 0010: 44 48 38 37 52 4c 20 20 40 01 00 00 49 4e 54 4c DH87RL @...INTL 0020: 01 00 00 00 26 00 00 00 00 00 00 00 00 00 00 00 ....&........... 0030: 00 00 10 00 01 00 00 00 00 00 00 00 00 00 00 00 ................ 0040: 01 00 30 00 00 00 00 00 00 b0 eb cb 00 00 00 00 ..0............. 0050: ff 9f ec cb 00 00 00 00 01 08 00 00 00 00 1d 00 ................ 0060: 01 08 00 00 00 00 1a 00 01 08 00 00 00 00 14 00 ................ 0070: 01 00 20 00 00 00 00 00 00 00 00 d7 00 00 00 00 .. ............. 0080: ff ff 1f df 00 00 00 00 01 08 00 00 00 00 02 00 ................ Turns out the i7-4770K doesn't support VT-d, so my current understanding is that there should be no DMAR table in the first place. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/