Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934936Ab3DIOXH (ORCPT ); Tue, 9 Apr 2013 10:23:07 -0400 Received: from co9ehsobe004.messaging.microsoft.com ([207.46.163.27]:27966 "EHLO co9outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762631Ab3DIOXF (ORCPT ); Tue, 9 Apr 2013 10:23:05 -0400 X-Forefront-Antispam-Report: CIP:163.181.249.109;KIP:(null);UIP:(null);IPV:NLI;H:ausb3twp02.amd.com;RD:none;EFVD:NLI X-SpamScore: -3 X-BigFish: VPS-3(zzbb2dI98dI9371I1432Izz1f42h1fc6h1ee6h1de0h1fdah1202h1e76h1d1ah1d2ahzzz2dh668h839h947he5bhf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h1765h18e1h190ch1946h19b4h19c3h1ad9h1b0ah1889i1155h) X-WSS-ID: 0MKZRY5-02-O1U-02 X-M-MSG: Message-ID: <51642442.7090908@amd.com> Date: Tue, 9 Apr 2013 09:22:58 -0500 From: Suravee Suthikulanit User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130307 Thunderbird/17.0.4 MIME-Version: 1.0 To: Joerg Roedel CC: , Subject: Re: [PATCH] iommu/amd: Add workaround to propery clearing IOMMU status register References: <1365031144-2543-1-git-send-email-suravee.suthikulpanit@amd.com> <20130409094929.GE6858@8bytes.org> In-Reply-To: <20130409094929.GE6858@8bytes.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-OriginatorOrg: amd.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1285 Lines: 35 On 4/9/2013 4:49 AM, Joerg Roedel wrote: > On Wed, Apr 03, 2013 at 06:19:04PM -0500, Suthikulpanit, Suravee wrote: >> In the system with multiple IOMMU,this handling scheme complicates the >> synchronization of the IOMMU data structures and status registers as >> there could be multiple threads competing for the same IOMMU while >> the other IOMMU could be left unhandled. > I really like that change in the interrupt handling code to pull the > different IOMMUs independently. But its problematic to change that in > the same patch that adds an erratum workaround. > > Please move that erratum fix into a seperate small patch that we can > backport to -stable and resend. > > > Joerg Joerg, The reason I implemented the "per-thread IOMMU handling" and the "workaround" together in one patch is because it simplifies the synchronization of clearing and checking the interrupt enabling bits. In the previous implementation, we could end up having multiple threads trying to access the status register at the same time. Suravee > > -- 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/