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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 D5A0CC43460 for ; Sat, 24 Apr 2021 07:26:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6DA761406 for ; Sat, 24 Apr 2021 07:26:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229682AbhDXH1G (ORCPT ); Sat, 24 Apr 2021 03:27:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229704AbhDXH1C (ORCPT ); Sat, 24 Apr 2021 03:27:02 -0400 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 909EFC061574; Sat, 24 Apr 2021 00:26:23 -0700 (PDT) Received: by mail-lj1-x236.google.com with SMTP id u25so19786803ljg.7; Sat, 24 Apr 2021 00:26:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=/pJRpObwgC760iXpBExu4yIVJmUUKVTuscTwMhK6LQU=; b=ufNx7c9rAdtARmP9/JGD2i8irzKzBRSUyNH+9fvRN92zRA0OBFhfjptFeAgu+DuB3q yfX+4Igr2ZTDK9BRrc56DlEvUt+BBNnplt01tCzit9YLV863swcxCrDFmUCr2AxIGVcC CA1deu2tXBGXlYmES7M4hHClqef3U0Z9Cc/5ESgmSCPAuPP+bV0Ejsxuz3yVgliRBNhq l5BHr8X0Lv0ae2Tcj/rgHxe19zUdxI6ucYdDvEo2Cgcmnq1RoX2WrGx7Zp+88tFQ+DRS iiC+cWOgjjaQN4BtP4v067DB6fjKQN6kZkQzdUOd2FMGfmB9Pv2H9LF2GfnYd4Oe/pkg jxIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=/pJRpObwgC760iXpBExu4yIVJmUUKVTuscTwMhK6LQU=; b=d6mIzzsi8RkTpBJEywPKdCo2+CV99ljHcpQUHqXmvCifvTbPFJj7S13Um8voFdjL6D Dp5f/A7hK80CQNAMkTR+QgdEXn9TC2EoiQKbz4xbhcKxplVH60XrENbuXtKZ7qLe/nSD DLSVpLMeARMPRS6Ftr1lfVjFsFm70iGoGfePM3gd0zwbsk3VRe6wIuy+L7pWbupmXJ1C m321DrGpCE9EurauBgOTh4vmcVAYnHcO+Aa6Ief4CB2isurQRYpiFZlWjC2VkCYIFDKn QGE5WbChpYWBwM+EVZF0AJ8nR9WtYZTLXdIEz+ja5jQPciL/qVUoY4b7Rjv/lGOisNGu PXWA== X-Gm-Message-State: AOAM530gigHi1VGReaNYMSCMWpiLSh5rDa83JQ6ALbI+Hc8D+aHyVNxb gjzAS+u0WSU2kB/q1hzH9jj6mmVoluo= X-Google-Smtp-Source: ABdhPJx3Cw5Vif+11oahK6V5zTzAwV00Iy/2ZrdiZkutRiszn4jYJ2cW57uWFklKK5dsA9oi5EN2hA== X-Received: by 2002:a2e:8054:: with SMTP id p20mr5032381ljg.439.1619249181690; Sat, 24 Apr 2021 00:26:21 -0700 (PDT) Received: from [192.168.2.145] (109-252-193-103.dynamic.spd-mgts.ru. [109.252.193.103]) by smtp.googlemail.com with ESMTPSA id t17sm749859ljd.35.2021.04.24.00.26.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 24 Apr 2021 00:26:21 -0700 (PDT) Subject: Re: [PATCH v2 0/5] iommu: Support identity mappings of reserved-memory regions To: Thierry Reding , Joerg Roedel , Rob Herring Cc: Will Deacon , Robin Murphy , Nicolin Chen , Krishna Reddy , devicetree@vger.kernel.org, iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org References: <20210423163234.3651547-1-thierry.reding@gmail.com> From: Dmitry Osipenko Message-ID: <869ec3a2-26df-2ce8-bd21-b681d6ef3985@gmail.com> Date: Sat, 24 Apr 2021 10:26:20 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210423163234.3651547-1-thierry.reding@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 23.04.2021 19:32, Thierry Reding пишет: > Hi, > > this is an updated proposal to solve the problem of passing memory > regions that are actively being accessed during boot. The particular > use-case that I need this for is when the bootloader has set up the > display controller to scan out a boot splash screen. During boot the > DMA/IOMMU glue code will attach devices to an IOMMU domain and by > doing so enable IOMMU translations. Typically this will be before a > device driver has had a chance to either disable the display > controller or set up a new framebuffer and map it to the IOMMU. Hello Thierry, Is it always safe to enable SMMU ASID in a middle of a DMA request made by a memory client? The memory controller supports blocking DMA requests, which we are already using for the memory hot-resetting. A block could be needed before ASID is toggled. This needs to be clarified.