From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 0/2] iommu: Fix regression in IOMMU grouping Date: Thu, 25 Sep 2014 16:40:35 +0200 Message-ID: <20140925144035.GC8306@8bytes.org> References: <20140919154944.14485.743.stgit@gimli.home> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20140919154944.14485.743.stgit-GCcqpEzw8uZBDLzU/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: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mstowe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Fri, Sep 19, 2014 at 10:03:00AM -0600, Alex Williamson wrote: > We've had surprisingly little fallout from the DMA alias changes, but > unfortunately one regression has popped up. We have an AMD system > that seems to use the SATA controller to master transactions for the > legacy IDE controller and they are different slots on the root complex. > The IVRS reports 00:11.0 (SATA) as an alias from 00:14.1 (IDE), which > doesn't work with the new, converged PCI IOMMU grouping code, where > we've made a simplifying assumption that aliases will be to the same > slot. > > To fix this, we need to rip out that assumption and write the alias > search code that I was unable to come up with previously. I think > this can now do the chaining of aliases, which I referenced in the > removed comments. Any sort of multi-level aliases are exceptionally > unlikely, but I think this code can now handle whatever firmware and > alias quirks can throw at it. Applied to core, thanks Alex. > > I know this is late for 3.17, but this is a regression from the prior > code. If reviews and testing can give us the confidence to put it in > for 3.17, that would be my preference. I've also marked it for stable > in case we want to loop back through that way. Thanks, The change is too big to make it into v3.17 at this point of the development cycle, so I queued it up for the upcoming merge window. Joerg