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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 940BBC43603 for ; Sat, 14 Dec 2019 01:53:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8367B214AF for ; Sat, 14 Dec 2019 01:53:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726691AbfLNBxm (ORCPT ); Fri, 13 Dec 2019 20:53:42 -0500 Received: from mga12.intel.com ([192.55.52.136]:46750 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726046AbfLNBxm (ORCPT ); Fri, 13 Dec 2019 20:53:42 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Dec 2019 17:53:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,311,1571727600"; d="scan'208";a="226462850" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 13 Dec 2019 17:53:38 -0800 Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] iommu/vt-d bad RMRR workarounds To: Barret Rhoden , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , David Woodhouse , Joerg Roedel , Yian Chen , Sohil Mehta References: <20191211194606.87940-1-brho@google.com> <35f49464-0ce5-9998-12a0-624d9683ea18@linux.intel.com> <8a530d5c-22e1-3c2f-98df-45028cc6c771@google.com> From: Lu Baolu Message-ID: <02d69d9a-9c45-d9e7-4c1a-cb5e50590c47@linux.intel.com> Date: Sat, 14 Dec 2019 09:52:50 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <8a530d5c-22e1-3c2f-98df-45028cc6c771@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/13/19 10:31 PM, Barret Rhoden wrote: > On 12/11/19 9:43 PM, Lu Baolu wrote: >> The VT-d spec defines the BIOS considerations about RMRR in section 8.4: >> >> " >> BIOS must report the RMRR reported memory addresses as reserved (or as >> EFI runtime) in the system memory map returned through methods such as >> INT15, EFI GetMemoryMap etc. >> " >> >> So we should treat it as firmware bug if the RMRR range is not mapped as >> RESERVED in the system memory map table. >> >> As for how should the driver handle this case, ignoring buggy RMRR with >> a warning message might be a possible choice. > > Agreed, firmware should not be doing this.  My first patch just skips > those entries, instead of aborting DMAR processing, and keeps the warning. > Hi Yian, Does this work for you? Best regards, baolu > So long as the machine still boots in a safe manner, I'm reasonably happy. > > Thanks, > > Barret > >