From: Joerg Roedel Subject: Re: [git pull] IOMMU Updates for v3.7-rc1 Date: Thu, 11 Oct 2012 11:32:39 +0200 Message-ID: <20121011093239.GA2619@amd.com> References: <20121005152312.GA4649@8bytes.org> <20121009224532.1e515664@ado-amd-gentoo.moore.slainvet.net> <20121010073022.GB16151@8bytes.org> <20121010095823.140fdd98@ado-amd-gentoo.moore.slainvet.net> <20121010133249.GC16151@8bytes.org> <20121010201131.091d5a1f@ado-amd-gentoo.moore.slainvet.net> <20121010230231.2fb3c3b9@ado-amd-gentoo.moore.slainvet.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20121010230231.2fb3c3b9-IjT0q3EH84DI7ueSY2wKCeWwSe/Luo9VmGrBRn/+eNheoWH0uzbU5w@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: Andrew Oakley Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Wed, Oct 10, 2012 at 11:02:31PM +0100, Andrew Oakley wrote: > On Wed, 10 Oct 2012 20:11:31 +0100 > Andrew Oakley wrote: > I'm not sure if the fix I've got is safe or if it's really a good idea > to enable interrupt remapping with a broken BIOS. Sadly it is not. Your patch works for your particular case but is not generally applicable. There are indeed systems with 2 or more IOAPICs and they all use different device-ids. So, typically, there is one IOAPIC per SB, like in your case. But on RD890 the chipset NB also includes an IOAPIC (which uses device-id 00:00.1). This IOAPIC exists on your system too but is disabled by the BIOS because the board does not use it. So, in the end, device-id 00:00.1 might also be correct and the IVRS entry could refer to the NB IOAPIC. We don't have any reliable indication which IOAPIC is described in the IVRS table. Cheer, Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632