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=-0.8 required=3.0 tests=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 75DD3C54FCC for ; Mon, 20 Apr 2020 07:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5287D21D82 for ; Mon, 20 Apr 2020 07:42:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="BM8Iccy/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726105AbgDTHmY (ORCPT ); Mon, 20 Apr 2020 03:42:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725815AbgDTHmY (ORCPT ); Mon, 20 Apr 2020 03:42:24 -0400 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05049C061A0C for ; Mon, 20 Apr 2020 00:42:24 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id k13so9621801wrw.7 for ; Mon, 20 Apr 2020 00:42:23 -0700 (PDT) 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=36LtjihBEpeBnaRGeeCm9e2L3d20jrMG7L1AL/HArJs=; b=BM8Iccy/hIQbCpSekYbFcZATX4MvhvRHEo8t56sYYDBHLuWrWlNfN2U/Avqh8pAzQ+ lJSChUqVOtITG+ntElIAo3FofQYlSUeJmVFTj1QctC3aH4uQ5UOifop/IzHxEXYnZ5my opGELuSrSZd/x7koJ8jWqGqe0lytTCYPvTb7bSWeBNbpH/ZOHDSjLzxqvp1xpOJsbc7o xGsbkEr+LTYIBgtKOpVnk5Pox8r0hmqVt3bRtQ6GUZafBrjVD4r2u3tGSKQbcyjfOLch 9Sfd2Iw3VJ/3lDfpUqoBIiiH3MRh0hqtXjIK8Ip29Za7xcLJ1b9QXuz0Pl6RJ3xDyOUI iYMQ== 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=36LtjihBEpeBnaRGeeCm9e2L3d20jrMG7L1AL/HArJs=; b=UiaAqMtI/hF9Tc3uSzyPOR8pEKd0DPRqdGWxw/5c6+mK9n7sYKQU0EYH7J781qU4/z yg8aMtu98Rj4x0dMmNNEH8MxYI1nZPpPPyhe0kLljo+hC2J0gowNpby55YU3c/Jy2Ons GCNOLzS0k+QezzwV/jOI9q9Dgv0tq3i9b7p5snmtSeL/gm65X/4WZmtRnAvzy34PKsmn YWLpKLh6ps70HwrXJuGvl9Wlm+igdu6LEwm8uDndNJyldNYPpeoqFxkMOQ2mkiqu/UnZ yCSxdYhyWtUKqERQZam+KF9COZXVFD42CvYmppoAXlqfUyvm/KDzI/Q56hZUWFGCymbU +dhw== X-Gm-Message-State: AGi0PubZqEUw1ldjZuZr41O2WWfTgMr8AAlnwD28omT7X0M4ehlo3EbA YO34WOEX3Oma5cknwAVUnGiC3w== X-Google-Smtp-Source: APiQypIBGqen1kzX4d4Wf5UYEkYdzKCnAPaaEvwxdtpe+zlIYgN/+aoVVamwm9Ox3hy3wg9aLlAaUA== X-Received: by 2002:a5d:6107:: with SMTP id v7mr16380670wrt.270.1587368542719; Mon, 20 Apr 2020 00:42:22 -0700 (PDT) Received: from myrica ([2001:171b:226b:54a0:116c:c27a:3e7f:5eaf]) by smtp.gmail.com with ESMTPSA id i25sm203507wml.43.2020.04.20.00.42.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2020 00:42:22 -0700 (PDT) Date: Mon, 20 Apr 2020 09:42:13 +0200 From: Jean-Philippe Brucker To: Christoph Hellwig Cc: iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, joro@8bytes.org, catalin.marinas@arm.com, will@kernel.org, robin.murphy@arm.com, kevin.tian@intel.com, baolu.lu@linux.intel.com, Jonathan.Cameron@huawei.com, jacob.jun.pan@linux.intel.com, christian.koenig@amd.com, zhangfei.gao@linaro.org, jgg@ziepe.ca, xuzaibo@huawei.com Subject: Re: [PATCH v5 02/25] iommu/sva: Manage process address spaces Message-ID: <20200420074213.GA3180232@myrica> References: <20200414170252.714402-1-jean-philippe@linaro.org> <20200414170252.714402-3-jean-philippe@linaro.org> <20200416072852.GA32000@infradead.org> <20200416085402.GB1286150@myrica> <20200416121331.GA18661@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200416121331.GA18661@infradead.org> Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Apr 16, 2020 at 05:13:31AM -0700, Christoph Hellwig wrote: > On Thu, Apr 16, 2020 at 10:54:02AM +0200, Jean-Philippe Brucker wrote: > > On Thu, Apr 16, 2020 at 12:28:52AM -0700, Christoph Hellwig wrote: > > > > + rcu_read_lock(); > > > > + hlist_for_each_entry_rcu(bond, &io_mm->devices, mm_node) > > > > + io_mm->ops->invalidate(bond->sva.dev, io_mm->pasid, io_mm->ctx, > > > > + start, end - start); > > > > + rcu_read_unlock(); > > > > +} > > > > > > What is the reason that the devices don't register their own notifiers? > > > This kinds of multiplexing is always rather messy, and you do it for > > > all the methods. > > > > This sends TLB and ATC invalidations through the IOMMU, it doesn't go > > through device drivers > > I don't think we mean the same thing, probably because of my rather > imprecise use of the word device. > > What I mean is that the mmu_notifier should not be embedded into the > io_mm structure (whch btw, seems to have a way to generic name, just > like all other io_* prefixed names), but instead into the > iommu_bond structure. That avoid the whole multiplexing layer. Right, I can see the appeal. I still like having a single mmu notifier per mm because it ensures we allocate a single PASID per mm (as required by x86). I suppose one alternative is to maintain a hashtable of mm->pasid, to avoid iterating over all bonds during allocation. 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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 31ED0C3815B for ; Mon, 20 Apr 2020 07:42:31 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 EB768206B8 for ; Mon, 20 Apr 2020 07:42:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="BM8Iccy/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB768206B8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 6E0242051F; Mon, 20 Apr 2020 07:42:30 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9N4JRXJ5K3v3; Mon, 20 Apr 2020 07:42:29 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id CE48A20392; Mon, 20 Apr 2020 07:42:28 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id A735BC07FF; Mon, 20 Apr 2020 07:42:28 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id B543FC0177 for ; Mon, 20 Apr 2020 07:42:27 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 9EC1386704 for ; Mon, 20 Apr 2020 07:42:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mT8ZAlQPWU0V for ; Mon, 20 Apr 2020 07:42:24 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-wr1-f67.google.com (mail-wr1-f67.google.com [209.85.221.67]) by whitealder.osuosl.org (Postfix) with ESMTPS id 922778634E for ; Mon, 20 Apr 2020 07:42:24 +0000 (UTC) Received: by mail-wr1-f67.google.com with SMTP id g13so8797942wrb.8 for ; Mon, 20 Apr 2020 00:42:24 -0700 (PDT) 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=36LtjihBEpeBnaRGeeCm9e2L3d20jrMG7L1AL/HArJs=; b=BM8Iccy/hIQbCpSekYbFcZATX4MvhvRHEo8t56sYYDBHLuWrWlNfN2U/Avqh8pAzQ+ lJSChUqVOtITG+ntElIAo3FofQYlSUeJmVFTj1QctC3aH4uQ5UOifop/IzHxEXYnZ5my opGELuSrSZd/x7koJ8jWqGqe0lytTCYPvTb7bSWeBNbpH/ZOHDSjLzxqvp1xpOJsbc7o xGsbkEr+LTYIBgtKOpVnk5Pox8r0hmqVt3bRtQ6GUZafBrjVD4r2u3tGSKQbcyjfOLch 9Sfd2Iw3VJ/3lDfpUqoBIiiH3MRh0hqtXjIK8Ip29Za7xcLJ1b9QXuz0Pl6RJ3xDyOUI iYMQ== 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=36LtjihBEpeBnaRGeeCm9e2L3d20jrMG7L1AL/HArJs=; b=jbK+F6PCb1Ioyjly9+sttHGQL8k7D6PmsSuO8/G6QFLQfYfq1mXOGdFV8SQpcRnWTf XHerRXb9aFxtdZjowjqkDfZz8Fhf8jO7ztQz3Zh+/yU04wmGqutaYoyswO3qIwAnRMC/ dU7PJi6pQKlEcBxJDWOdzbzR+VaCn9ru9fUW9phWVMM20ywdvCmy/SMsr3ducR1da+Dk 8plfBzeD0JTBxpatgOm8LYHKBNE6M7Zx5X3pSoaccRSpvSZEXtmwl7xxqWbdMaY9J4rU sZQTE2rraxnzr5kpETNnsQ8McVeE2ySHIdD0jRo9lZaqxQd2zSJo0r2cfXKIVrHJv3y+ eH2g== X-Gm-Message-State: AGi0PuZN842IAJEDQQP8toFhDFYd/8sQIhedk7etL+0TCxlJNRmjz7vY mTYHXr9ZGMPOc/Iw+h8K0WjhbQ== X-Google-Smtp-Source: APiQypIBGqen1kzX4d4Wf5UYEkYdzKCnAPaaEvwxdtpe+zlIYgN/+aoVVamwm9Ox3hy3wg9aLlAaUA== X-Received: by 2002:a5d:6107:: with SMTP id v7mr16380670wrt.270.1587368542719; Mon, 20 Apr 2020 00:42:22 -0700 (PDT) Received: from myrica ([2001:171b:226b:54a0:116c:c27a:3e7f:5eaf]) by smtp.gmail.com with ESMTPSA id i25sm203507wml.43.2020.04.20.00.42.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2020 00:42:22 -0700 (PDT) Date: Mon, 20 Apr 2020 09:42:13 +0200 From: Jean-Philippe Brucker To: Christoph Hellwig Subject: Re: [PATCH v5 02/25] iommu/sva: Manage process address spaces Message-ID: <20200420074213.GA3180232@myrica> References: <20200414170252.714402-1-jean-philippe@linaro.org> <20200414170252.714402-3-jean-philippe@linaro.org> <20200416072852.GA32000@infradead.org> <20200416085402.GB1286150@myrica> <20200416121331.GA18661@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200416121331.GA18661@infradead.org> Cc: devicetree@vger.kernel.org, kevin.tian@intel.com, jgg@ziepe.ca, linux-pci@vger.kernel.org, robin.murphy@arm.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, catalin.marinas@arm.com, zhangfei.gao@linaro.org, will@kernel.org, christian.koenig@amd.com, linux-arm-kernel@lists.infradead.org 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, Apr 16, 2020 at 05:13:31AM -0700, Christoph Hellwig wrote: > On Thu, Apr 16, 2020 at 10:54:02AM +0200, Jean-Philippe Brucker wrote: > > On Thu, Apr 16, 2020 at 12:28:52AM -0700, Christoph Hellwig wrote: > > > > + rcu_read_lock(); > > > > + hlist_for_each_entry_rcu(bond, &io_mm->devices, mm_node) > > > > + io_mm->ops->invalidate(bond->sva.dev, io_mm->pasid, io_mm->ctx, > > > > + start, end - start); > > > > + rcu_read_unlock(); > > > > +} > > > > > > What is the reason that the devices don't register their own notifiers? > > > This kinds of multiplexing is always rather messy, and you do it for > > > all the methods. > > > > This sends TLB and ATC invalidations through the IOMMU, it doesn't go > > through device drivers > > I don't think we mean the same thing, probably because of my rather > imprecise use of the word device. > > What I mean is that the mmu_notifier should not be embedded into the > io_mm structure (whch btw, seems to have a way to generic name, just > like all other io_* prefixed names), but instead into the > iommu_bond structure. That avoid the whole multiplexing layer. Right, I can see the appeal. I still like having a single mmu notifier per mm because it ensures we allocate a single PASID per mm (as required by x86). I suppose one alternative is to maintain a hashtable of mm->pasid, to avoid iterating over all bonds during allocation. Thanks, Jean _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu 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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 92C11C54FCC for ; Mon, 20 Apr 2020 07:42:31 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 69DF6218AC for ; Mon, 20 Apr 2020 07:42:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="THA3uZ03"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="BM8Iccy/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 69DF6218AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.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:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=21fhs/pw43FeZVSTzQwvcfPA4ImWJcIGRni0OApBMS4=; b=THA3uZ03Q6ktL4 m5ZLsbOdzPGvc32ueFgSFWzOYjRQr9u4qnapTZiQpWXuLaT92+TVp+5qkhmuTN3dxECX5dpM4R9Im ubLUBPG+yBDDkHhpYGCS2AcdcLqUXqkwnHWUh6LYngKvzyVzpphmIaoq9wwyYLWkwIU6K0HVz5kpY Ak8qVLS227/AGLQCiFg9zCNWuQuWv2QDUsfUMUiUP7CMZVJLX7KzX5e9cbSqXF6/kdT1tXfzc3Mws JDVhgMT6gAAo/I1nQiytiqIGMN0CIgLJJ7zhgm7bIAGvlrVMPbV+luqMu4pZ6XhjP15ZtOa8NduoF 6XWmg8HRby8BOSnyAnqA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQR4V-00033r-NC; Mon, 20 Apr 2020 07:42:27 +0000 Received: from mail-wr1-x441.google.com ([2a00:1450:4864:20::441]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQR4S-00033F-8B for linux-arm-kernel@lists.infradead.org; Mon, 20 Apr 2020 07:42:25 +0000 Received: by mail-wr1-x441.google.com with SMTP id x18so10862637wrq.2 for ; Mon, 20 Apr 2020 00:42:23 -0700 (PDT) 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=36LtjihBEpeBnaRGeeCm9e2L3d20jrMG7L1AL/HArJs=; b=BM8Iccy/hIQbCpSekYbFcZATX4MvhvRHEo8t56sYYDBHLuWrWlNfN2U/Avqh8pAzQ+ lJSChUqVOtITG+ntElIAo3FofQYlSUeJmVFTj1QctC3aH4uQ5UOifop/IzHxEXYnZ5my opGELuSrSZd/x7koJ8jWqGqe0lytTCYPvTb7bSWeBNbpH/ZOHDSjLzxqvp1xpOJsbc7o xGsbkEr+LTYIBgtKOpVnk5Pox8r0hmqVt3bRtQ6GUZafBrjVD4r2u3tGSKQbcyjfOLch 9Sfd2Iw3VJ/3lDfpUqoBIiiH3MRh0hqtXjIK8Ip29Za7xcLJ1b9QXuz0Pl6RJ3xDyOUI iYMQ== 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=36LtjihBEpeBnaRGeeCm9e2L3d20jrMG7L1AL/HArJs=; b=leKql0UbZyPWoKoxSspY5irqGo75U01ZvTkfQrs5iAtviJVqEr5kB0kDEA5g+zw78b p9tPIjb9wrS2U1A6udQvkWCAw7sUhfO+mhy/tOLPeC3dtMBpGfdijmM8sjAOC7tf8dV8 7e8lXcxS5YQ5dkerSzL/KeQiTyYiJ8iJgdcMtv69CsZaHjBEVVaacCyi38o3p9tpH+7M MEhmzxBAnjCJTRnISmv5N9Q7oNnfnnY7DBSn/BVBPD+pZGx+xvpOMb2AL8+md/hPhbd7 a0GQEHqaCl8yXzwKgZDtq2uHbGKksOx+PTrK8iUF01eOXK12S2hdXiHUZkGU87CAfDDd GY7Q== X-Gm-Message-State: AGi0PuYvJMJ5dlypBfWqrIDdyC+4j3ND4hyMDSnmYq/TiHNWQ3hvOpj5 f8Qn0ocU79la6QcWKUYod1UQ5A== X-Google-Smtp-Source: APiQypIBGqen1kzX4d4Wf5UYEkYdzKCnAPaaEvwxdtpe+zlIYgN/+aoVVamwm9Ox3hy3wg9aLlAaUA== X-Received: by 2002:a5d:6107:: with SMTP id v7mr16380670wrt.270.1587368542719; Mon, 20 Apr 2020 00:42:22 -0700 (PDT) Received: from myrica ([2001:171b:226b:54a0:116c:c27a:3e7f:5eaf]) by smtp.gmail.com with ESMTPSA id i25sm203507wml.43.2020.04.20.00.42.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2020 00:42:22 -0700 (PDT) Date: Mon, 20 Apr 2020 09:42:13 +0200 From: Jean-Philippe Brucker To: Christoph Hellwig Subject: Re: [PATCH v5 02/25] iommu/sva: Manage process address spaces Message-ID: <20200420074213.GA3180232@myrica> References: <20200414170252.714402-1-jean-philippe@linaro.org> <20200414170252.714402-3-jean-philippe@linaro.org> <20200416072852.GA32000@infradead.org> <20200416085402.GB1286150@myrica> <20200416121331.GA18661@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200416121331.GA18661@infradead.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200420_004224_304939_20E8490F X-CRM114-Status: GOOD ( 15.02 ) 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: devicetree@vger.kernel.org, kevin.tian@intel.com, jacob.jun.pan@linux.intel.com, jgg@ziepe.ca, linux-pci@vger.kernel.org, joro@8bytes.org, Jonathan.Cameron@huawei.com, robin.murphy@arm.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, catalin.marinas@arm.com, zhangfei.gao@linaro.org, xuzaibo@huawei.com, will@kernel.org, christian.koenig@amd.com, linux-arm-kernel@lists.infradead.org, baolu.lu@linux.intel.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Apr 16, 2020 at 05:13:31AM -0700, Christoph Hellwig wrote: > On Thu, Apr 16, 2020 at 10:54:02AM +0200, Jean-Philippe Brucker wrote: > > On Thu, Apr 16, 2020 at 12:28:52AM -0700, Christoph Hellwig wrote: > > > > + rcu_read_lock(); > > > > + hlist_for_each_entry_rcu(bond, &io_mm->devices, mm_node) > > > > + io_mm->ops->invalidate(bond->sva.dev, io_mm->pasid, io_mm->ctx, > > > > + start, end - start); > > > > + rcu_read_unlock(); > > > > +} > > > > > > What is the reason that the devices don't register their own notifiers? > > > This kinds of multiplexing is always rather messy, and you do it for > > > all the methods. > > > > This sends TLB and ATC invalidations through the IOMMU, it doesn't go > > through device drivers > > I don't think we mean the same thing, probably because of my rather > imprecise use of the word device. > > What I mean is that the mmu_notifier should not be embedded into the > io_mm structure (whch btw, seems to have a way to generic name, just > like all other io_* prefixed names), but instead into the > iommu_bond structure. That avoid the whole multiplexing layer. Right, I can see the appeal. I still like having a single mmu notifier per mm because it ensures we allocate a single PASID per mm (as required by x86). I suppose one alternative is to maintain a hashtable of mm->pasid, to avoid iterating over all bonds during allocation. Thanks, Jean _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel