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,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 EEAD2C433DB for ; Tue, 16 Mar 2021 09:24:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B761964FB3 for ; Tue, 16 Mar 2021 09:24:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236036AbhCPJYD (ORCPT ); Tue, 16 Mar 2021 05:24:03 -0400 Received: from mga02.intel.com ([134.134.136.20]:46862 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236223AbhCPJXt (ORCPT ); Tue, 16 Mar 2021 05:23:49 -0400 IronPort-SDR: fBF0X3rxgJUcQVWEPD4kLyVdgK0EYWh0y7KvNOpl5v9f8mh0sKnqfgXiPqTLBCrtuf2PHNyrGg DMkWPSsUYV0w== X-IronPort-AV: E=McAfee;i="6000,8403,9924"; a="176359553" X-IronPort-AV: E=Sophos;i="5.81,251,1610438400"; d="scan'208";a="176359553" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2021 02:23:40 -0700 IronPort-SDR: CrQEz3Ag/ybTmE/AKIhoS6JlqMs8jIsDGXGu3qBz2a7xb6J+XW5eh5kL00OMxdeOM628wp1Rb5 /se5GT1T9v/Q== X-IronPort-AV: E=Sophos;i="5.81,251,1610438400"; d="scan'208";a="449660949" Received: from yisun1-ubuntu.bj.intel.com (HELO yi.y.sun) ([10.238.156.116]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-SHA256; 16 Mar 2021 02:23:35 -0700 Date: Tue, 16 Mar 2021 17:17:51 +0800 From: Yi Sun To: Keqian Zhu Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, Alex Williamson , Robin Murphy , Will Deacon , Kirti Wankhede , Cornelia Huck , Marc Zyngier , Catalin Marinas , Mark Rutland , James Morse , Suzuki K Poulose , wanghaibin.wang@huawei.com, jiangkunkun@huawei.com, yuzenghui@huawei.com, lushenming@huawei.com Subject: Re: [PATCH v2 04/11] iommu/arm-smmu-v3: Split block descriptor when start dirty log Message-ID: <20210316091751.GN28580@yi.y.sun> References: <20210310090614.26668-1-zhukeqian1@huawei.com> <20210310090614.26668-5-zhukeqian1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210310090614.26668-5-zhukeqian1@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21-03-10 17:06:07, Keqian Zhu wrote: > From: jiangkunkun > > Block descriptor is not a proper granule for dirty log tracking. > Take an extreme example, if DMA writes one byte, under 1G mapping, > the dirty amount reported to userspace is 1G, but under 4K mapping, > the dirty amount is just 4K. > > This adds a new interface named start_dirty_log in iommu layer and > arm smmuv3 implements it, which splits block descriptor to an span > of page descriptors. Other types of IOMMU will perform architecture > specific actions to start dirty log. > > To allow code reuse, the split_block operation is realized as an > iommu_ops too. We flush all iotlbs after the whole procedure is > completed to ease the pressure of iommu, as we will hanle a huge > range of mapping in general. > > Spliting block does not simultaneously work with other pgtable ops, > as the only designed user is vfio, which always hold a lock, so race > condition is not considered in the pgtable ops. > > Co-developed-by: Keqian Zhu > Signed-off-by: Kunkun Jiang > --- > > changelog: > > v2: > - Change the return type of split_block(). size_t -> int. > - Change commit message to properly describe race condition. (Robin) > - Change commit message to properly describe the need of split block. > - Add a new interface named start_dirty_log(). (Sun Yi) > - Change commit message to explain the realtionship of split_block() and start_dirty_log(). > > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 52 +++++++++ > drivers/iommu/io-pgtable-arm.c | 122 ++++++++++++++++++++ > drivers/iommu/iommu.c | 48 ++++++++ > include/linux/io-pgtable.h | 2 + > include/linux/iommu.h | 24 ++++ > 5 files changed, 248 insertions(+) > Could you please split iommu common interface to a separate patch? This may make review and comments easier. IMHO, I think the start/stop interfaces could be merged into one, e.g: int iommu_domain_set_hwdbm(struct iommu_domain *domain, bool enable, unsigned long iova, size_t size, int prot); Same comments to patch 5. BRs, Yi Sun > -- > 2.19.1