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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92411C433FE for ; Fri, 10 Dec 2021 09:06:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239057AbhLJJKY (ORCPT ); Fri, 10 Dec 2021 04:10:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234276AbhLJJKX (ORCPT ); Fri, 10 Dec 2021 04:10:23 -0500 Received: from mail-ed1-x534.google.com (mail-ed1-x534.google.com [IPv6:2a00:1450:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 522B0C061746 for ; Fri, 10 Dec 2021 01:06:48 -0800 (PST) Received: by mail-ed1-x534.google.com with SMTP id w1so27591590edc.6 for ; Fri, 10 Dec 2021 01:06:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=p51Nz29s/4zmZ+EPSD75GUmiIaP5D91+aCSEQZKR7mY=; b=w0/20eIpOstfeq4XyG6SkmuCg0ION+5jLGBpP6vias0+7A0TxUpXOgqgAoOTZ4QTXN wAYFBxEEsCB1XdI237RbMAMOgXiUuIQRB7hnO2KBN3T22RrD0M2HvPKcHqfnxduCWPtL CBFRfUVhrE7VGPWNvtwIHwQkKo/+JblWxwlbflPf8kc8ikqftYje0ih6EYKEBcYnhHlc zw4jkifcFLQ/ohA3A+4FtKNDC2KuYHsaAJ0qudJumUaejaQMja/v/kYOFlhHSnEW28px uFPLpwq9cg9NNnbfvhYKNtMkha7CpwF/2sbn2ST+miB5XzMxb8zF6C9MQRu32KEFjOO3 UyBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=p51Nz29s/4zmZ+EPSD75GUmiIaP5D91+aCSEQZKR7mY=; b=aT+w5+3RPxCR6NTwGuCb4h2RlgFAX7+vh8U9m1ydIGcpwjC6gdEiz5W5OPKHcN2rcE R6nCAg85jIlSX7p14+fFOlvpIvNQCNDjl01MGr40M5Q9zeTRxet32BJMwB7/lFZtKtS2 CkySsJdoeyE3Ab/d5sQVE869q7VQ1U7wTcpZx2aShWis0pR4obE2wkxlhHAIHoDNDW5U HT7P7WObDAaaKMA8JyJblj3WierZlDJuwG+Q+fSNU+XSyRE7pytupRpeMnrvl7GciOS3 QFigDN7IPYGa+g0tRvlU7my4NAxy7Ggfmzj0h3JuZh0HnS2vB1QVw5d392oKgRlEWOST VdXQ== X-Gm-Message-State: AOAM532zYHe7VgbflDbmBpZ/p/BWTROW0g5XyqyI7vxh/Gijbo2vaARG raHQ5ROp2HelvEEIhYMGyKpv/Q== X-Google-Smtp-Source: ABdhPJzzl9GYf5cjF2Z03Bwf6HwuUK34ncwmWm/jaDIJ7LMJxa/P7TYdoO0r7pqId0sfN/uLkPSH1Q== X-Received: by 2002:a05:6402:1e93:: with SMTP id f19mr37545678edf.60.1639127206878; Fri, 10 Dec 2021 01:06:46 -0800 (PST) Received: from myrica (cpc92880-cmbg19-2-0-cust679.5-4.cable.virginm.net. [82.27.106.168]) by smtp.gmail.com with ESMTPSA id mp26sm1135173ejc.61.2021.12.10.01.06.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Dec 2021 01:06:46 -0800 (PST) Date: Fri, 10 Dec 2021 09:06:24 +0000 From: Jean-Philippe Brucker To: Jacob Pan Cc: iommu@lists.linux-foundation.org, LKML , Joerg Roedel , Jason Gunthorpe , Christoph Hellwig , Greg Kroah-Hartman , Jean-Philippe Brucker , Jacob Pan , Lu Baolu , Raj Ashok , "Kumar, Sanjay K" , Dave Jiang , Tony Luck , Yi Liu , "Tian, Kevin" , Barry Song <21cnbao@gmail.com>, "Zanussi, Tom" , Dan Williams Subject: Re: [PATCH 1/4] ioasid: Reserve a global PASID for in-kernel DMA Message-ID: References: <1638884834-83028-1-git-send-email-jacob.jun.pan@linux.intel.com> <1638884834-83028-2-git-send-email-jacob.jun.pan@linux.intel.com> <20211209101404.6aefbe1c@jacob-builder> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211209101404.6aefbe1c@jacob-builder> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 09, 2021 at 10:14:04AM -0800, Jacob Pan wrote: > > This looks like we're just one step away from device drivers needing > > multiple PASIDs for kernel DMA so I'm trying to figure out how to evolve > > the API towards that. It's probably as simple as keeping a kernel IOASID > > set at first, but then we'll probably want to optimize by having multiple > > overlapping sets for each device driver (all separate from the SVA set). > Sounds reasonable to start with a kernel set for in-kernel DMA once we need > multiple ones. But I am not sure what *overlapping* sets mean here, could > you explain? Given that each device uses a separate PASID table, we could allocate the same set of PASID values for different device drivers. We just need to make sure that those values are different from PASIDs allocated for user SVA. Thanks, Jean 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 Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BF9ECC433F5 for ; Fri, 10 Dec 2021 09:06:54 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 532EE85217; Fri, 10 Dec 2021 09:06:54 +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 rdfDTuIXLIxk; Fri, 10 Dec 2021 09:06:53 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id 779078520F; Fri, 10 Dec 2021 09:06:52 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 411BBC001E; Fri, 10 Dec 2021 09:06:52 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [IPv6:2605:bc80:3010::133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 72C42C0012 for ; Fri, 10 Dec 2021 09:06:50 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 4BD65401F1 for ; Fri, 10 Dec 2021 09:06:50 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp2.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=linaro.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Fb6zcdim6QY1 for ; Fri, 10 Dec 2021 09:06:49 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-ed1-x531.google.com (mail-ed1-x531.google.com [IPv6:2a00:1450:4864:20::531]) by smtp2.osuosl.org (Postfix) with ESMTPS id CE729400A8 for ; Fri, 10 Dec 2021 09:06:48 +0000 (UTC) Received: by mail-ed1-x531.google.com with SMTP id w1so27591592edc.6 for ; Fri, 10 Dec 2021 01:06:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=p51Nz29s/4zmZ+EPSD75GUmiIaP5D91+aCSEQZKR7mY=; b=w0/20eIpOstfeq4XyG6SkmuCg0ION+5jLGBpP6vias0+7A0TxUpXOgqgAoOTZ4QTXN wAYFBxEEsCB1XdI237RbMAMOgXiUuIQRB7hnO2KBN3T22RrD0M2HvPKcHqfnxduCWPtL CBFRfUVhrE7VGPWNvtwIHwQkKo/+JblWxwlbflPf8kc8ikqftYje0ih6EYKEBcYnhHlc zw4jkifcFLQ/ohA3A+4FtKNDC2KuYHsaAJ0qudJumUaejaQMja/v/kYOFlhHSnEW28px uFPLpwq9cg9NNnbfvhYKNtMkha7CpwF/2sbn2ST+miB5XzMxb8zF6C9MQRu32KEFjOO3 UyBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=p51Nz29s/4zmZ+EPSD75GUmiIaP5D91+aCSEQZKR7mY=; b=uEojWbL3LaBvsmk1WPd5dvUZ145EXYJngoIqo1xHsnsTrLavfohUvy5ydY6Xz9NndN PF7s+YYY5++pZgBp89g9pZ8qUiRl8pwDfFmTccbql5cA8I7icSWvqZgofwS2eDmV17r5 aGtnz8YrIgiGdsSEA8M5wosb6Vskk2KbDca/czXhjvsv00Rg/cwvWqqRUbIL7KkJp0ty t5JO5C8wGxF1qz1on/UVFRPZ8UbYwDIODJFWK0Z6JR7Eow1Lh0C2Zv9AnbDU23YZMCJo GVUZ33QI3y9/KuHleD3Wv4VC+3kRY6s53Yjn3MRjdNuL/rc6LSp9WyewPVf5Ngigg164 8ABQ== X-Gm-Message-State: AOAM530jEtmsC/vz5XHsgJBjVHVIXYBd9TVvhEMGFzqXdbC9cFUbV4Tw EPmv5k96Vtp6MEsHXDExnwtO1w== X-Google-Smtp-Source: ABdhPJzzl9GYf5cjF2Z03Bwf6HwuUK34ncwmWm/jaDIJ7LMJxa/P7TYdoO0r7pqId0sfN/uLkPSH1Q== X-Received: by 2002:a05:6402:1e93:: with SMTP id f19mr37545678edf.60.1639127206878; Fri, 10 Dec 2021 01:06:46 -0800 (PST) Received: from myrica (cpc92880-cmbg19-2-0-cust679.5-4.cable.virginm.net. [82.27.106.168]) by smtp.gmail.com with ESMTPSA id mp26sm1135173ejc.61.2021.12.10.01.06.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Dec 2021 01:06:46 -0800 (PST) Date: Fri, 10 Dec 2021 09:06:24 +0000 From: Jean-Philippe Brucker To: Jacob Pan Subject: Re: [PATCH 1/4] ioasid: Reserve a global PASID for in-kernel DMA Message-ID: References: <1638884834-83028-1-git-send-email-jacob.jun.pan@linux.intel.com> <1638884834-83028-2-git-send-email-jacob.jun.pan@linux.intel.com> <20211209101404.6aefbe1c@jacob-builder> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211209101404.6aefbe1c@jacob-builder> Cc: "Tian, Kevin" , Tony Luck , Dave Jiang , Raj Ashok , Greg Kroah-Hartman , "Kumar, Sanjay K" , LKML , Christoph Hellwig , iommu@lists.linux-foundation.org, Jacob Pan , Jason Gunthorpe , Barry Song <21cnbao@gmail.com>, Dan Williams , Jean-Philippe Brucker , "Zanussi, Tom" 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Thu, Dec 09, 2021 at 10:14:04AM -0800, Jacob Pan wrote: > > This looks like we're just one step away from device drivers needing > > multiple PASIDs for kernel DMA so I'm trying to figure out how to evolve > > the API towards that. It's probably as simple as keeping a kernel IOASID > > set at first, but then we'll probably want to optimize by having multiple > > overlapping sets for each device driver (all separate from the SVA set). > Sounds reasonable to start with a kernel set for in-kernel DMA once we need > multiple ones. But I am not sure what *overlapping* sets mean here, could > you explain? Given that each device uses a separate PASID table, we could allocate the same set of PASID values for different device drivers. We just need to make sure that those values are different from PASIDs allocated for user SVA. Thanks, Jean _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu