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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 10CE6C4332B for ; Sat, 21 Mar 2020 01:32:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2F6D20752 for ; Sat, 21 Mar 2020 01:32:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727899AbgCUBct (ORCPT ); Fri, 20 Mar 2020 21:32:49 -0400 Received: from mga11.intel.com ([192.55.52.93]:51726 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726840AbgCUBct (ORCPT ); Fri, 20 Mar 2020 21:32:49 -0400 IronPort-SDR: KAvBP2651Is0hWWXfmUPbPwswqY7XL0J8M7lMfwx6ZHujFFjNDRBjWZ21Awwwiz8QsGYYwOcH6 wI2NVL6P7IoA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Mar 2020 18:32:48 -0700 IronPort-SDR: bXMDXjJLJZodiuHPyhNhLQnhRC3EAGO3pLsdO9Vn0wH5EGRPtbOjHaj5g71r+Uft+ETIZad4+i hYzFwvRA5JCg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,286,1580803200"; d="scan'208";a="249051243" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.211.188]) ([10.254.211.188]) by orsmga006.jf.intel.com with ESMTP; 20 Mar 2020 18:32:45 -0700 Cc: baolu.lu@linux.intel.com, LKML , iommu@lists.linux-foundation.org, Joerg Roedel , David Woodhouse , Raj Ashok , Yi Liu Subject: Re: [PATCH 1/3] iommu/vt-d: Remove redundant IOTLB flush To: Jacob Pan References: <1584678751-43169-1-git-send-email-jacob.jun.pan@linux.intel.com> <1584678751-43169-2-git-send-email-jacob.jun.pan@linux.intel.com> <26ab1917-f087-aafa-e861-6a2478000a6f@linux.intel.com> <20200320092047.4a4cf551@jacob-builder> From: Lu Baolu Message-ID: <06c9751a-417d-3c32-65af-0788593f811a@linux.intel.com> Date: Sat, 21 Mar 2020 09:32:45 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200320092047.4a4cf551@jacob-builder> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/3/21 0:20, Jacob Pan wrote: > On Fri, 20 Mar 2020 21:45:26 +0800 > Lu Baolu wrote: > >> On 2020/3/20 12:32, Jacob Pan wrote: >>> IOTLB flush already included in the PASID tear down process. There >>> is no need to flush again. >> >> It seems that intel_pasid_tear_down_entry() doesn't flush the pasid >> based device TLB? >> > I saw this code in intel_pasid_tear_down_entry(). Isn't the last line > flush the devtlb? Not in guest of course since the passdown tlb flush > is inclusive. > > pasid_cache_invalidation_with_pasid(iommu, did, pasid); > iotlb_invalidation_with_pasid(iommu, did, pasid); > > /* Device IOTLB doesn't need to be flushed in caching mode. */ > if (!cap_caching_mode(iommu->cap)) > devtlb_invalidation_with_pasid(iommu, dev, pasid); > But devtlb_invalidation_with_pasid() doesn't do the right thing, it flushes the device tlb, instead of pasid-based device tlb. static void devtlb_invalidation_with_pasid(struct intel_iommu *iommu, struct device *dev, int pasid) { struct device_domain_info *info; u16 sid, qdep, pfsid; info = dev->archdata.iommu; if (!info || !info->ats_enabled) return; sid = info->bus << 8 | info->devfn; qdep = info->ats_qdep; pfsid = info->pfsid; qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 - VTD_PAGE_SHIFT); } Best regards, baolu >> Best regards, >> baolu >> >>> >>> Cc: Lu Baolu >>> Signed-off-by: Jacob Pan >>> --- >>> drivers/iommu/intel-svm.c | 6 ++---- >>> 1 file changed, 2 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c >>> index 8f42d717d8d7..1483f1845762 100644 >>> --- a/drivers/iommu/intel-svm.c >>> +++ b/drivers/iommu/intel-svm.c >>> @@ -268,10 +268,9 @@ static void intel_mm_release(struct >>> mmu_notifier *mn, struct mm_struct *mm) >>> * *has* to handle gracefully without affecting other >>> processes. */ >>> rcu_read_lock(); >>> - list_for_each_entry_rcu(sdev, &svm->devs, list) { >>> + list_for_each_entry_rcu(sdev, &svm->devs, list) >>> intel_pasid_tear_down_entry(svm->iommu, >>> sdev->dev, svm->pasid); >>> - intel_flush_svm_range_dev(svm, sdev, 0, -1, 0); >>> - } >>> + >>> rcu_read_unlock(); >>> >>> } >>> @@ -731,7 +730,6 @@ int intel_svm_unbind_mm(struct device *dev, int >>> pasid) >>> * large and has to be physically >>> contiguous. So it's >>> * hard to be as defensive as we might >>> like. */ intel_pasid_tear_down_entry(iommu, dev, svm->pasid); >>> - intel_flush_svm_range_dev(svm, sdev, 0, >>> -1, 0); kfree_rcu(sdev, rcu); >>> >>> if (list_empty(&svm->devs)) { >>> > > [Jacob Pan] >