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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 870DDC433E0 for ; Thu, 28 Jan 2021 15:21:45 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 146FC64DEF for ; Thu, 28 Jan 2021 15:21:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 146FC64DEF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RgG09py387eQSgkGTs1f+4YCq7jnPJK09ADm0DJYDLY=; b=dnmZSpqkh9OZqlw6InHi5+ggb ngp6K9M2O2eRIEnh7DkjRbrbz1ofXK7yq5HqfqDeMJXNBj+hJZOE9Hm6CciZWLe0V16lpr00+MVnM KQYV9V0h57Vzp8z2C+v57y64PWGeFH3nxLvsnOEJhsI4TfYVYfEWqV0wcGVg79CDGRwynANZ1Ab0B yymEPVW5xA7I9b/betpCaIQ/wgDlJV3kZMOjy7qT2tMLTnffRj+xaIO8kDA43p77Ooj6/undATS4F KDobC4g/hhIgm6O6r+74c6AS+8zlt4dPsaZj2iTu1Ds6HKM5Ej6uZHQtZmeK+SBWTi5ASSq4yxLLG H1QlSRNuA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l5965-0004zt-Hp; Thu, 28 Jan 2021 15:20:37 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l594e-0004Jz-Af for linux-arm-kernel@lists.infradead.org; Thu, 28 Jan 2021 15:19:10 +0000 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4DRPH86F54zjDTK; Thu, 28 Jan 2021 23:17:56 +0800 (CST) Received: from [10.174.184.42] (10.174.184.42) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.498.0; Thu, 28 Jan 2021 23:18:46 +0800 Subject: Re: [PATCH 1/1] iommu/arm-smmu-v3: add support for BBML To: Robin Murphy , Will Deacon References: <20201126034230.777-1-thunder.leizhen@huawei.com> <20210122125132.GB24102@willie-the-truck> <1bfd1ca0-953e-e943-f87e-144d5537bd0c@arm.com> <20210126101230.GA29204@willie-the-truck> <8a9685ec-67aa-824f-5429-f408bf79c5ab@huawei.com> <32f4752f-6954-183a-a0c1-b5d719c85b67@huawei.com> <319e3532-4555-7431-9d6f-3c3b7c11a5d9@arm.com> From: Keqian Zhu Message-ID: Date: Thu, 28 Jan 2021 23:18:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <319e3532-4555-7431-9d6f-3c3b7c11a5d9@arm.com> X-Originating-IP: [10.174.184.42] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210128_101909_476289_F55120BB X-CRM114-Status: GOOD ( 15.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jean-Philippe Brucker , iommu , linux-kernel , linux-arm-kernel , Yang Yingliang Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2021/1/27 17:39, Robin Murphy wrote: > On 2021-01-27 07:36, Keqian Zhu wrote: >> >> >> On 2021/1/27 10:01, Leizhen (ThunderTown) wrote: >>> >>> >>> On 2021/1/26 18:12, Will Deacon wrote: >>>> On Mon, Jan 25, 2021 at 08:23:40PM +0000, Robin Murphy wrote: >>>>> Now we probably will need some degreee of BBML feature awareness for the >>>>> sake of SVA if and when we start using it for CPU pagetables, but I still >>>>> cannot see any need to consider it in io-pgtable. >>>> >>>> Agreed; I don't think this is something that io-pgtable should have to care >>>> about. >> Hi, >> >> I have a question here :-). >> If the old table is not live, then the break procedure seems unnecessary. Do I miss something? > > The MMU is allowed to prefetch translations at any time, so not following the proper update procedure could still potentially lead to a TLB conflict, even if there's no device traffic to worry about disrupting. > > Robin. Thanks. Does the MMU you mention here includes MMU and SMMU? I know that at SMMU side, ATS can prefetch translation. Keqian > >> Thanks, >> Keqian >> >>> >>> Yes, the SVA works in stall mode, and the failed device access requests are not >>> discarded. >>> >>> Let me look for examples. The BBML usage scenario was told by a former colleague. >>> >>>> >>>> Will >>>> >>>> . >>>> >>> >>> >>> _______________________________________________ >>> linux-arm-kernel mailing list >>> linux-arm-kernel@lists.infradead.org >>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>> . >>> >> _______________________________________________ >> iommu mailing list >> iommu@lists.linux-foundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/iommu >> > . > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel