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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_NONE,USER_AGENT_SANE_1 autolearn=unavailable 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 BC944C43470 for ; Wed, 12 May 2021 11:32:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 848F5613CF for ; Wed, 12 May 2021 11:32:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230216AbhELLdp (ORCPT ); Wed, 12 May 2021 07:33:45 -0400 Received: from mga01.intel.com ([192.55.52.88]:47247 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230037AbhELLdo (ORCPT ); Wed, 12 May 2021 07:33:44 -0400 IronPort-SDR: KKfR39WQ4b17wAnitTpLLttnAkcwWq7ba/hTv12hQj8aQPU7u4No/iUDWC1DeSv4Mqzgyt17pH dOQlJ1lVBieQ== X-IronPort-AV: E=McAfee;i="6200,9189,9981"; a="220652412" X-IronPort-AV: E=Sophos;i="5.82,293,1613462400"; d="scan'208";a="220652412" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 May 2021 04:32:11 -0700 IronPort-SDR: GM0y7i9w2gAupgR5Q0lhYEchbcbaaim1usJ+WvbY5KptixLGwgEioF21ntWT3v7XBDMdSfnAId uY8AH9uHx/0A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,293,1613462400"; d="scan'208";a="622371382" Received: from allen-box.sh.intel.com (HELO [10.239.159.128]) ([10.239.159.128]) by fmsmga006.fm.intel.com with ESMTP; 12 May 2021 04:32:08 -0700 Cc: baolu.lu@linux.intel.com, "Raj, Ashok" , "Pan, Jacob jun" , "Liu, Yi L" , "Kumar, Sanjay K" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/1] iommu/vt-d: Support asynchronous IOMMU nested capabilities To: "Tian, Kevin" , Joerg Roedel , Will Deacon References: <20210512070421.3472857-1-baolu.lu@linux.intel.com> From: Lu Baolu Message-ID: <2eb677d1-14d7-c1dc-6dd4-179c11c76b10@linux.intel.com> Date: Wed, 12 May 2021 19:31:22 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 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 Kevin, On 5/12/21 4:30 PM, Tian, Kevin wrote: >> From: Lu Baolu >> Sent: Wednesday, May 12, 2021 3:04 PM >> >> Current VT-d implementation supports nested translation only if all >> underlying IOMMUs support the nested capability. This is unnecessary >> as the upper layer is allowed to create different containers and set >> them with different type of iommu backend. The IOMMU driver needs to >> guarantee that devices attached to a nested mode iommu_domain should >> support nested capabilility. > > so the consistency check is now applied only to the IOMMUs that are > spanned by a given iommu_domain? Yes. > >> >> Signed-off-by: Lu Baolu >> --- >> drivers/iommu/intel/iommu.c | 21 +++++++++++++++++++-- >> 1 file changed, 19 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c >> index f1742da42478..1cd4840e6f9f 100644 >> --- a/drivers/iommu/intel/iommu.c >> +++ b/drivers/iommu/intel/iommu.c >> @@ -4755,6 +4755,13 @@ static int prepare_domain_attach_device(struct >> iommu_domain *domain, >> if (!iommu) >> return -ENODEV; >> >> + if ((dmar_domain->flags & DOMAIN_FLAG_NESTING_MODE) && >> + !ecap_nest(iommu->ecap)) { >> + dev_err(dev, "%s: iommu not support nested translation\n", >> + iommu->name); >> + return -EINVAL; >> + } >> + >> /* check if this iommu agaw is sufficient for max mapped address */ >> addr_width = agaw_to_width(iommu->agaw); >> if (addr_width > cap_mgaw(iommu->cap)) >> @@ -5451,11 +5458,21 @@ static int >> intel_iommu_enable_nesting(struct iommu_domain *domain) >> { >> struct dmar_domain *dmar_domain = to_dmar_domain(domain); >> + struct dmar_drhd_unit *drhd; >> + struct intel_iommu *iommu; >> + bool has_nesting = false; >> unsigned long flags; >> - int ret = -ENODEV; >> + int ret = -EINVAL; >> + >> + for_each_active_iommu(iommu, drhd) >> + if (ecap_nest(iommu->ecap)) >> + has_nesting = true; >> + >> + if (!has_nesting) >> + return -ENODEV; > > Isn't above still doing global consistency check? The logic is if nested mode is globally unsupported, return false. > >> >> spin_lock_irqsave(&device_domain_lock, flags); >> - if (nested_mode_support() && list_empty(&dmar_domain->devices)) >> { >> + if (list_empty(&dmar_domain->devices)) { >> dmar_domain->flags |= DOMAIN_FLAG_NESTING_MODE; >> dmar_domain->flags &= ~DOMAIN_FLAG_USE_FIRST_LEVEL; >> ret = 0; >> -- >> 2.25.1 > Best regards, baolu