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=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 76BE5C433B4 for ; Fri, 2 Apr 2021 04:53:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E8A7610E7 for ; Fri, 2 Apr 2021 04:53:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229691AbhDBEx3 (ORCPT ); Fri, 2 Apr 2021 00:53:29 -0400 Received: from mga14.intel.com ([192.55.52.115]:50358 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229518AbhDBEx1 (ORCPT ); Fri, 2 Apr 2021 00:53:27 -0400 IronPort-SDR: sBNyMtZEIrSFXv1l4R0jg55WB3X45Awh/TdbGQzycMAjKq/K7Mg77UMtuJa5ZuZQSVLPKoI3xK 51MFS44QE07g== X-IronPort-AV: E=McAfee;i="6000,8403,9941"; a="191869860" X-IronPort-AV: E=Sophos;i="5.81,298,1610438400"; d="scan'208";a="191869860" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2021 21:53:26 -0700 IronPort-SDR: wrvsYJM85qho+rwKDNnxzVYqmYVmd532nChyBcTpoLpAENCHNdIRC5iMpxu6hAlLcPjZYmiSvU D1OFOT0HBDGw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,298,1610438400"; d="scan'208";a="439476626" Received: from allen-box.sh.intel.com (HELO [10.239.159.128]) ([10.239.159.128]) by fmsmga004.fm.intel.com with ESMTP; 01 Apr 2021 21:53:24 -0700 Cc: baolu.lu@linux.intel.com, David Woodhouse , Nadav Amit , Alex Williamson , Kevin Tian , Gonglei , stable@vger.kernel.org Subject: Re: [PATCH] iommu/vt-d: Force to flush iotlb before creating superpage To: "Longpeng(Mike)" , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20210401071834.1639-1-longpeng2@huawei.com> From: Lu Baolu Message-ID: <9c368419-6e45-6b27-0f34-26b581589fa7@linux.intel.com> Date: Fri, 2 Apr 2021 12:44:02 +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: <20210401071834.1639-1-longpeng2@huawei.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 Longpeng, On 4/1/21 3:18 PM, Longpeng(Mike) wrote: > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index ee09323..cbcb434 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -2342,9 +2342,20 @@ static inline int hardware_largepage_caps(struct dmar_domain *domain, > * removed to make room for superpage(s). > * We're adding new large pages, so make sure > * we don't remove their parent tables. > + * > + * We also need to flush the iotlb before creating > + * superpage to ensure it does not perserves any > + * obsolete info. > */ > - dma_pte_free_pagetable(domain, iov_pfn, end_pfn, > - largepage_lvl + 1); > + if (dma_pte_present(pte)) { The dma_pte_free_pagetable() clears a batch of PTEs. So checking current PTE is insufficient. How about removing this check and always performing cache invalidation? > + int i; > + > + dma_pte_free_pagetable(domain, iov_pfn, end_pfn, > + largepage_lvl + 1); > + for_each_domain_iommu(i, domain) > + iommu_flush_iotlb_psi(g_iommus[i], domain, > + iov_pfn, nr_pages, 0, 0); > + Best regards, baolu