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 59DDAC43603 for ; Mon, 16 Dec 2019 19:11:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2237B20717 for ; Mon, 16 Dec 2019 19:11:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726858AbfLPTLj (ORCPT ); Mon, 16 Dec 2019 14:11:39 -0500 Received: from mga06.intel.com ([134.134.136.31]:59458 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726426AbfLPTLi (ORCPT ); Mon, 16 Dec 2019 14:11:38 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Dec 2019 11:11:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,322,1571727600"; d="scan'208";a="212129807" Received: from chenyian-desk1.amr.corp.intel.com (HELO [10.3.52.63]) ([10.3.52.63]) by fmsmga007.fm.intel.com with ESMTP; 16 Dec 2019 11:11:37 -0800 Subject: Re: [PATCH 0/3] iommu/vt-d bad RMRR workarounds To: Lu Baolu , Barret Rhoden , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , David Woodhouse , Joerg Roedel , Sohil Mehta Cc: iommu@lists.linux-foundation.org, x86@kernel.org, linux-kernel@vger.kernel.org References: <20191211194606.87940-1-brho@google.com> <35f49464-0ce5-9998-12a0-624d9683ea18@linux.intel.com> <8a530d5c-22e1-3c2f-98df-45028cc6c771@google.com> <02d69d9a-9c45-d9e7-4c1a-cb5e50590c47@linux.intel.com> From: "Chen, Yian" Message-ID: Date: Mon, 16 Dec 2019 11:11:37 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <02d69d9a-9c45-d9e7-4c1a-cb5e50590c47@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/13/2019 5:52 PM, Lu Baolu wrote: > > 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 > > I made a comment in the the patch email "[PATCH 1/3] iommu/vt-d: skip RMRR entries that fail the sanity check " thanks, Yian >> So long as the machine still boots in a safe manner, I'm reasonably >> happy. >> >> Thanks, >> >> Barret >> >>