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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 3FFD0C433E0 for ; Mon, 1 Feb 2021 23:45:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 026E164ECE for ; Mon, 1 Feb 2021 23:45:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230411AbhBAXpJ (ORCPT ); Mon, 1 Feb 2021 18:45:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229683AbhBAXpG (ORCPT ); Mon, 1 Feb 2021 18:45:06 -0500 Received: from mail-qt1-x836.google.com (mail-qt1-x836.google.com [IPv6:2607:f8b0:4864:20::836]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A91D7C061573 for ; Mon, 1 Feb 2021 15:44:26 -0800 (PST) Received: by mail-qt1-x836.google.com with SMTP id n8so5353846qtp.5 for ; Mon, 01 Feb 2021 15:44:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=hd15FyljMQNb+uHNxQHOyHL+pJdt7H/rF6CqnCRNxkk=; b=k2UK7o8wQKpImEwvMcIofjhqZsF1yjn8WEus+jyV+wEKwNI6Pdakb/8qDqgA9xjczP 2vPN1SEc50w2MpyQ7LD+ynXBrNS0ZUMPypuqH73q3LZlHiLudFcbUX2YEdbVreK9GYci hvcm6XoNqV/208cemLwAqA8+PAHjy3gR92TFTOvBBJo7+cm3ioe3aJ52NRp9dC77mPPw oDjDm0ZwCbl0N5JT1o7/W7KfF4QzaCcJx0mZ8QBXv8kRecO95ouX8OEHg3EnsSZjoY8b iZ3BuClJKbypxdM6+deF5MQjc1yclCNHXNUNBUtjO3Rt+RPjmfdltzBcWVgFq5Wf8gYo bQ/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=hd15FyljMQNb+uHNxQHOyHL+pJdt7H/rF6CqnCRNxkk=; b=WfrViVDmW8w09CyQt4wlfcO+VND4VunItHdksdFW3QrCQSYvPGWdxkCrMWKvPv1fzW Hv8H1MT5USW5bVSExR22GhB1VxEfMsqo7rb12n9MzgPSZCucSHUoiZry710q1zJ0Div5 KEyMb1d8694MJKLP4cXJfr1ErBRzYBVCJanYxKFN+MiKG3eAHLHLvC2lekW2ec/47oyP JVy70xphjM04nVvSEP0/j4BRaTDxnkcL9NaZiFpzluAzQ1gKAdAm+e/SdtvSThWD3im9 suTbfDBRX4dFYM/kP045syuZr/Lob4H4q6qVrzy3QHw8Xxsfggwps46sXWJtBTrixcQ6 +6RQ== X-Gm-Message-State: AOAM53249Z8scFJ05DLJJyKvNJ0XU3YksRZTby8aWwVpwYdlh14FSpX4 11qzOwuv1sGX2XEn+JftlcCnU8+GzWJ89rrl X-Google-Smtp-Source: ABdhPJxOk/Gr3FI8hipqpO78EuQbpqBCvzEwZtZKwnaYmY8JYjMc8WYuBvCPpUv8lB3nlvifrKdI9g== X-Received: by 2002:ac8:6c48:: with SMTP id z8mr17373676qtu.252.1612223065836; Mon, 01 Feb 2021 15:44:25 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-115-133.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.115.133]) by smtp.gmail.com with ESMTPSA id p22sm15466415qkk.128.2021.02.01.15.44.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Feb 2021 15:44:25 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1l6iro-002MnI-P8; Mon, 01 Feb 2021 19:44:24 -0400 Date: Mon, 1 Feb 2021 19:44:24 -0400 From: Jason Gunthorpe To: "Tian, Kevin" Cc: "Song Bao Hua (Barry Song)" , "chensihang (A)" , Arnd Bergmann , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-mm@kvack.org" , Zhangfei Gao , "Liguozhu (Kenneth)" , "linux-accelerators@lists.ozlabs.org" Subject: Re: [RFC PATCH v2] uacce: Add uacce_ctrl misc device Message-ID: <20210201234424.GI4718@ziepe.ca> References: <1611563696-235269-1-git-send-email-wangzhou1@hisilicon.com> <20210125154717.GW4605@ziepe.ca> <96b655ade2534a65974a378bb68383ee@hisilicon.com> <20210125231619.GY4605@ziepe.ca> <5f64a68042c64f37b5cba74028bd2189@hisilicon.com> <20210126011304.GZ4605@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 29, 2021 at 10:09:03AM +0000, Tian, Kevin wrote: > > SVA is not doom to work with IO page fault only. If we have SVA+pin, > > we would get both sharing address and stable I/O latency. > > Isn't it like a traditional MAP_DMA API (imply pinning) plus specifying > cpu_va of the memory pool as the iova? I think their issue is the HW can't do the cpu_va trick without also involving the system IOMMU in a SVA mode It really is something that belongs under some general /dev/sva as we talked on the vfio thread Jason