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_PATCH,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 86B19C63697 for ; Thu, 26 Nov 2020 11:01:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 30D6121D46 for ; Thu, 26 Nov 2020 11:01:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729628AbgKZLBm (ORCPT ); Thu, 26 Nov 2020 06:01:42 -0500 Received: from mga03.intel.com ([134.134.136.65]:17403 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726392AbgKZLBl (ORCPT ); Thu, 26 Nov 2020 06:01:41 -0500 IronPort-SDR: Um3fYwmFz6BgIkd2hBKNeCv3eyQpqs0Vej8tfnD/OUS2eRo8ybHpyG/5zG2JivJC6lN0u6z4r6 K+DSDGGe49TA== X-IronPort-AV: E=McAfee;i="6000,8403,9816"; a="172369014" X-IronPort-AV: E=Sophos;i="5.78,371,1599548400"; d="scan'208";a="172369014" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Nov 2020 03:01:41 -0800 IronPort-SDR: Om6vgDtmXzckxRMzuk+Reuc8HaZOQeNd/UuAAr+/lzBarbHv1aFMn7wMMR+U5lfqjz5W2e1drU iMnYzAvzUePg== X-IronPort-AV: E=Sophos;i="5.78,371,1599548400"; d="scan'208";a="479317121" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.208.39]) ([10.254.208.39]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Nov 2020 03:01:39 -0800 Cc: baolu.lu@linux.intel.com Subject: Re: Question about domain_init (v5.3-v5.7) To: Jerry Snitselaar , Joerg Roedel , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, stable@kernel.vger.org References: <87h7pd6v2k.fsf@redhat.com> From: Lu Baolu Message-ID: Date: Thu, 26 Nov 2020 19:01:36 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <87h7pd6v2k.fsf@redhat.com> 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 Jerry, On 2020/11/26 4:27, Jerry Snitselaar wrote: > > Is there a reason we check the requested guest address width against the > iommu's mgaw, instead of the agaw that we already know for the iommu? > I've run into a case with a new system where the mgaw reported is 57, > but if they set PAE to 46 instead of 52 in the bios, then sagaw reports > the highest supported agaw is 48 and the domain_init code fails here. In Isn't this a platform bug? If it's too late to fix it in the BIOS, you maybe have to add a platform specific quirk to set mgaw to the highest supported agaw? Best regards, baolu > other places like prepare_domain_attach_device, the dmar domain agaw > gets adjusted down to the iommu agaw. The agaw of the iommu gets > determined based off what is reported for sagaw. I'm wondering if it > can't instead do: > > --- > drivers/iommu/intel-iommu.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 6ca5c92ef2e5..a8e41ec36d9e 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -1862,8 +1862,8 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu, > domain_reserve_special_ranges(domain); > > /* calculate AGAW */ > - if (guest_width > cap_mgaw(iommu->cap)) > - guest_width = cap_mgaw(iommu->cap); > + if (guest_width > agaw_to_width(iommu->agaw)) > + guest_width = agaw_to_width(iommu->agaw); > domain->gaw = guest_width; > adjust_width = guestwidth_to_adjustwidth(guest_width); > agaw = width_to_agaw(adjust_width); > -- > 2.27.0 > > > Thoughts? With the former code the ehci device for the ilo fails when > trying to get a private domain. > > Thanks, > Jerry >