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=-15.3 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_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 4A284C43461 for ; Wed, 14 Apr 2021 07:24:19 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EA047613B1 for ; Wed, 14 Apr 2021 07:24:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA047613B1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id ABA0040295; Wed, 14 Apr 2021 07:24:18 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EABygVYhN2NA; Wed, 14 Apr 2021 07:24:17 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp4.osuosl.org (Postfix) with ESMTP id 39FF740285; Wed, 14 Apr 2021 07:24:17 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id F346EC000B; Wed, 14 Apr 2021 07:24:16 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 02F6BC000A for ; Wed, 14 Apr 2021 07:24:16 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id D56F283C00 for ; Wed, 14 Apr 2021 07:24:15 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id xd0OzL3Yl7xl for ; Wed, 14 Apr 2021 07:24:14 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by smtp1.osuosl.org (Postfix) with ESMTPS id B496983BE8 for ; Wed, 14 Apr 2021 07:24:14 +0000 (UTC) IronPort-SDR: 1sntTJolxMjNEvs0SFuRCLBzt/TfYVZUQh2Q1fCMC7dYDqntk282hNARLV8GBeX1IjmvRxf8Ox QsUnxpShhswg== X-IronPort-AV: E=McAfee;i="6200,9189,9953"; a="194611276" X-IronPort-AV: E=Sophos;i="5.82,221,1613462400"; d="scan'208";a="194611276" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2021 00:24:13 -0700 IronPort-SDR: 35lROPy9KaI3sWZf4uqKtjH/Qunpt9OTUZ5AFPasffdrQiGF7IKnLpGAMJwBXoXQVlETsZ32D6 mVt3msA3+Tgw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,221,1613462400"; d="scan'208";a="443720741" Received: from allen-box.sh.intel.com (HELO [10.239.159.128]) ([10.239.159.128]) by fmsmga004.fm.intel.com with ESMTP; 14 Apr 2021 00:24:09 -0700 Subject: Re: [PATCH v3 02/12] iommu: Add iommu_split_block interface To: Keqian Zhu , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, Robin Murphy , Will Deacon , Joerg Roedel , Yi Sun , Jean-Philippe Brucker , Jonathan Cameron , Tian Kevin References: <20210413085457.25400-1-zhukeqian1@huawei.com> <20210413085457.25400-3-zhukeqian1@huawei.com> From: Lu Baolu Message-ID: Date: Wed, 14 Apr 2021 15:14:32 +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: <20210413085457.25400-3-zhukeqian1@huawei.com> Content-Language: en-US Cc: jiangkunkun@huawei.com, Cornelia Huck , Kirti Wankhede , lushenming@huawei.com, Alex Williamson , wanghaibin.wang@huawei.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 4/13/21 4:54 PM, Keqian Zhu wrote: > Block(largepage) mapping 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 is 1G, but under 4K mapping, the dirty amount is > just 4K. > > This adds a new interface named iommu_split_block in IOMMU base layer. > A specific IOMMU driver can invoke it during start dirty log. If so, the > driver also need to realize the split_block iommu ops. > > 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. > > Signed-off-by: Keqian Zhu > Signed-off-by: Kunkun Jiang > --- > drivers/iommu/iommu.c | 41 +++++++++++++++++++++++++++++++++++++++++ > include/linux/iommu.h | 11 +++++++++++ > 2 files changed, 52 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 667b2d6d2fc0..bb413a927870 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2721,6 +2721,47 @@ int iommu_domain_set_attr(struct iommu_domain *domain, > } > EXPORT_SYMBOL_GPL(iommu_domain_set_attr); > > +int iommu_split_block(struct iommu_domain *domain, unsigned long iova, > + size_t size) > +{ > + const struct iommu_ops *ops = domain->ops; > + unsigned int min_pagesz; > + size_t pgsize; > + bool flush = false; > + int ret = 0; > + > + if (unlikely(!ops || !ops->split_block)) > + return -ENODEV; > + > + min_pagesz = 1 << __ffs(domain->pgsize_bitmap); > + if (!IS_ALIGNED(iova | size, min_pagesz)) { > + pr_err("unaligned: iova 0x%lx size 0x%zx min_pagesz 0x%x\n", > + iova, size, min_pagesz); > + return -EINVAL; > + } > + > + while (size) { > + flush = true; > + > + pgsize = iommu_pgsize(domain, iova, size); > + > + ret = ops->split_block(domain, iova, pgsize); > + if (ret) > + break; > + > + pr_debug("split handled: iova 0x%lx size 0x%zx\n", iova, pgsize); > + > + iova += pgsize; > + size -= pgsize; > + } > + > + if (flush) > + iommu_flush_iotlb_all(domain); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(iommu_split_block); Do you really have any consumers of this interface other than the dirty bit tracking? If not, I don't suggest to make this as a generic IOMMU interface. There is an implicit requirement for such interfaces. The iommu_map/unmap(iova, size) shouldn't be called at the same time. Currently there's no such sanity check in the iommu core. A poorly written driver could mess up the kernel by misusing this interface. This also applies to iommu_merge_page(). Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu