From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Roedel, Joerg" Subject: Re: 3.6-rc7 boot crash + bisection Date: Wed, 26 Sep 2012 17:10:44 +0200 Message-ID: <20120926151044.GE10549@amd.com> References: <20120924210348.5f50677b@brain.lan> <1348597970.28860.114.camel@bling.home> <20120925205420.0a07dea2@brain.lan> <1348602226.28860.132.camel@bling.home> <20120926132050.GB10549@amd.com> <1348670159.28860.183.camel@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1348670159.28860.183.camel-xdHQ/5r00wBBDLzU/O5InQ@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: Alex Williamson Cc: Florian Dazinger , iommu , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Wed, Sep 26, 2012 at 08:35:59AM -0600, Alex Williamson wrote: > Hmm, that throws a kink in iommu groups. So perhaps we need to make an > alias interface to iommu groups. Seems like this could just be an extra > parameter to iommu_group_get and iommu_group_add_device (empty in the > typical case). Then we have the problem of what's the type for an > alias? For AMI-Vi, it's a u16, but we need to be more generic than > that. Maybe iommu groups should just treat it as a void* so iommus can > use a pointer to some structure or a fixed value like a u16 bus:slot. > Thoughts? Good question. The iommu-groups are part of the IOMMU-API, with an interface to the IOMMU drivers and one to the users of IOMMU-API. So the alias handling itself should be a function of the interface to the IOMMU driver. In general the interface should not be bus specific. So a void pointer seems the only logical choice then. But I would not limit its scope to alias handling. How about making it a bus-private pointer where IOMMU driver store bus-specific information. That way we make sure that there is one struct per bus-type for this pointer, and not one structure per IOMMU driver. 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