From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C49EC433E0 for ; Fri, 19 Mar 2021 01:18:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4059964DF4 for ; Fri, 19 Mar 2021 01:18:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232495AbhCSBRU (ORCPT ); Thu, 18 Mar 2021 21:17:20 -0400 Received: from mga12.intel.com ([192.55.52.136]:65016 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232294AbhCSBRK (ORCPT ); Thu, 18 Mar 2021 21:17:10 -0400 IronPort-SDR: h6kow5YS7Z3Z7uF9S5JbhhoZkt54ZAzjT4YSLt2mceYBOXCweP0u2HLph7FoaVWbDpa2yfG1lV mM0WL/XacEhg== X-IronPort-AV: E=McAfee;i="6000,8403,9927"; a="169099095" X-IronPort-AV: E=Sophos;i="5.81,259,1610438400"; d="scan'208";a="169099095" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2021 18:17:10 -0700 IronPort-SDR: EZxk9hyQ01Dram0VtQCI65jzNEPNaWLaxQpwmj69Fobyw5TK0Be4rvPzSGzUE4pccInPp4Bu0R CYyskGyJIL7Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,259,1610438400"; d="scan'208";a="434080025" Received: from allen-box.sh.intel.com (HELO [10.239.159.128]) ([10.239.159.128]) by fmsmga004.fm.intel.com with ESMTP; 18 Mar 2021 18:17:07 -0700 Cc: baolu.lu@linux.intel.com, Will Deacon , ashok.raj@intel.com, kevin.tian@intel.com, jacob.jun.pan@intel.com, yi.l.liu@intel.com, sanjay.k.kumar@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jacob Pan Subject: Re: [PATCH 1/1] iommu/vt-d: Don't set then immediately clear in prq_event_thread() To: Joerg Roedel References: <20210309004641.3809653-1-baolu.lu@linux.intel.com> From: Lu Baolu Message-ID: Date: Fri, 19 Mar 2021 09:07:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joerg, On 3/18/21 6:10 PM, Joerg Roedel wrote: > Hi Baolu, > > On Tue, Mar 09, 2021 at 08:46:41AM +0800, Lu Baolu wrote: >> The private data field of a page group response descriptor is set then >> immediately cleared in prq_event_thread(). Fix this by moving clearing >> code up. >> >> Fixes: 5b438f4ba315d ("iommu/vt-d: Support page request in scalable mode") >> Cc: Jacob Pan >> Reviewed-by: Liu Yi L >> Signed-off-by: Lu Baolu > > Does this fix an actual bug? If so, please state it in the commit It will cause real problem according to the VT-d spec. I haven't got a chance run this on a real hardware yet. I'll add a commit message to explain why this will cause problem. > message and also fix the subject line to state what is set/cleared. > Sure! > Thanks, > > Joerg > Best regards, baolu