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 EDC28C2D0CD for ; Wed, 18 Dec 2019 16:08:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C32AA2072B for ; Wed, 18 Dec 2019 16:08:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="vGdwPfRl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726980AbfLRQIn (ORCPT ); Wed, 18 Dec 2019 11:08:43 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:35348 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727160AbfLRQIn (ORCPT ); Wed, 18 Dec 2019 11:08:43 -0500 Received: by mail-wm1-f65.google.com with SMTP id p17so2531066wmb.0 for ; Wed, 18 Dec 2019 08:08:40 -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=o5X12+OnlTrR6hQB7btD1TwyQhH770WeXItNc7qt5zA=; b=vGdwPfRl1Ha9VhwGDZb29pGKHmrCLBjEh/aU/lWfjiA+Es/jr7ZphzP4HzPPmjTJx+ JSehVhXPNzXdOHN1KvgmcYfeFj+EOqqLkQfTn7w+aSzsmY9sA/Phabc6P4xORTt9/1CX ZeJvajjFb7Aa2pPQS2rmj8CC2WfmH3g8R6Icy6BCtWh0myJTrzSd94GfQGUovkp6jd2B rT+HoiZRDI9Poe0mNpRZQO9dQfwLmHSchdxzCs4OzzEO+QNZJtdaxkDjf9S6U0pGGXCC uBxrbddT9q0O1xSpIKLYhBMvxSFqGMIVi9YEcXDMHetlYODSFxx8S1+dGvzAMam0zV9q MZyA== 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=o5X12+OnlTrR6hQB7btD1TwyQhH770WeXItNc7qt5zA=; b=npxXRB1OrrDTPCXk4Wd7e9VE1oefIe12bdRgXIwcgTYGgaSZvKCXCwkkwr9r4T7JeR ZYiMUl1rnBeEy5Txc9qCBtwj3PaMyOSItbXSQUJvp5/xiAoxPhdnDxAYHyRac9kRvke5 H3fSx/GaOuDYvi2dYHyY43x0zDmvblPrYwzOdDiZUVc1DkBVUKoV/wxbHdE+0Xce3id7 sOPl9nz+6qWXb3nf+rBkEwFpj01YK5HTACNu56T0yfu9QPplnyk96GrIP7At18g0ymo7 jsHvmRFRcCK+hVBlxnZSA5QT55mjeBW71xd+YrjaRyMMI0ouM+nvsinNFWP3b9yagUUX C9cw== X-Gm-Message-State: APjAAAWndB2xHu6HSD35bMpZzuzwJFw+S2mBHHp3Z9IHlAz1VULWI/w2 I2HgqvxIYVN80lmi2A8PbBrgKQ== X-Google-Smtp-Source: APXvYqzGNVeQ/R7JR9UNdXnpKZSm9sCG7ntxjETJuNIvtVXZ9l8S+gdw6OnN9egWqIdDF5D4ZyEZUA== X-Received: by 2002:a05:600c:22c8:: with SMTP id 8mr3940980wmg.178.1576685320145; Wed, 18 Dec 2019 08:08:40 -0800 (PST) Received: from myrica (adsl-84-227-176-239.adslplus.ch. [84.227.176.239]) by smtp.gmail.com with ESMTPSA id c5sm2949884wmb.9.2019.12.18.08.08.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 08:08:39 -0800 (PST) Date: Wed, 18 Dec 2019 17:08:34 +0100 From: Jean-Philippe Brucker To: Auger Eric Cc: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, iommu@lists.linux-foundation.org, joro@8bytes.org, robh+dt@kernel.org, mark.rutland@arm.com, lorenzo.pieralisi@arm.com, guohanjun@huawei.com, sudeep.holla@arm.com, rjw@rjwysocki.net, lenb@kernel.org, will@kernel.org, robin.murphy@arm.com, bhelgaas@google.com, jonathan.cameron@huawei.com, zhangfei.gao@linaro.org Subject: Re: [PATCH v3 08/13] iommu/arm-smmu-v3: Propate ssid_bits Message-ID: <20191218160834.GG2371701@myrica> References: <20191209180514.272727-1-jean-philippe@linaro.org> <20191209180514.272727-9-jean-philippe@linaro.org> <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tue, Dec 17, 2019 at 06:07:26PM +0100, Auger Eric wrote: > Hi Jean, > > On 12/9/19 7:05 PM, Jean-Philippe Brucker wrote: > > s/Propate/Propagate in the commit title. > > Now that we support substream IDs, initialize s1cdmax with the number of > > SSID bits supported by a master and the SMMU. > > > > Context descriptor tables are allocated once for the first master > > attached to a domain. Therefore attaching multiple devices with > > different SSID sizes is tricky, and we currently don't support it. > > > > As a future improvement it would be nice to at least support attaching a > > SSID-capable device to a domain that isn't using SSID, by reallocating > > the SSID table. > Isn't that use case relevant (I mean using both devices in a non SSID > use case). For platform devices you can work this around with FW but for > PCI devices? Normally each device gets its own domain. Especially since PASID is a PCI Express capability, I expect them to be properly isolated with ACS, each with its own IOMMU group. So I don't think this is too relevant for the moment, it would be a quirk for a broken system. 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 A4EADC43603 for ; Wed, 18 Dec 2019 16:08:48 +0000 (UTC) Received: from whitealder.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 mail.kernel.org (Postfix) with ESMTPS id 72C272176D for ; Wed, 18 Dec 2019 16:08:48 +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="vGdwPfRl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 72C272176D 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 whitealder.osuosl.org (Postfix) with ESMTP id 3A50087B08; Wed, 18 Dec 2019 16:08:48 +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 9zKsMi43ZQFB; Wed, 18 Dec 2019 16:08:47 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id A01D18766D; Wed, 18 Dec 2019 16:08:46 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3EAABC1797; Wed, 18 Dec 2019 16:08:46 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0DBE5C077D for ; Wed, 18 Dec 2019 16:08:45 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id EFCAF204F2 for ; Wed, 18 Dec 2019 16:08:44 +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 Ac+YO4-T5KJq for ; Wed, 18 Dec 2019 16:08:43 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-wm1-f68.google.com (mail-wm1-f68.google.com [209.85.128.68]) by silver.osuosl.org (Postfix) with ESMTPS id D1B1820407 for ; Wed, 18 Dec 2019 16:08:41 +0000 (UTC) Received: by mail-wm1-f68.google.com with SMTP id d73so2419664wmd.1 for ; Wed, 18 Dec 2019 08:08:41 -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=o5X12+OnlTrR6hQB7btD1TwyQhH770WeXItNc7qt5zA=; b=vGdwPfRl1Ha9VhwGDZb29pGKHmrCLBjEh/aU/lWfjiA+Es/jr7ZphzP4HzPPmjTJx+ JSehVhXPNzXdOHN1KvgmcYfeFj+EOqqLkQfTn7w+aSzsmY9sA/Phabc6P4xORTt9/1CX ZeJvajjFb7Aa2pPQS2rmj8CC2WfmH3g8R6Icy6BCtWh0myJTrzSd94GfQGUovkp6jd2B rT+HoiZRDI9Poe0mNpRZQO9dQfwLmHSchdxzCs4OzzEO+QNZJtdaxkDjf9S6U0pGGXCC uBxrbddT9q0O1xSpIKLYhBMvxSFqGMIVi9YEcXDMHetlYODSFxx8S1+dGvzAMam0zV9q MZyA== 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=o5X12+OnlTrR6hQB7btD1TwyQhH770WeXItNc7qt5zA=; b=jysjCachcqbZaT1MMx7Uv99oL0vau1oQTBoxrVtplaZfgQ45lSlsZXyG+ZJj4c85OS vUtDNSg/P835IfKmliL14yFh89O4GOMjfyZGnjeqG7FN0iyFJvv4n5icWdySwE/6wQeA 1bDnpFHt2MiEaw9FOKTYbCEtmnLR9f0mLo1JScS6ClCAAWfn5mQHdQe2YKJ92kHANZEl 6ya0yjWYLcO6iqsf5/LwwE+kj8mCyzAqbeUtcrsIIDbSwQ0Y/7E5Jau3a230NFEdjLan ORLZH4b+Gpt0eA+mvv6dl5N+gahNo0Dsc7lmmwo6A4AY+/ct/CV+vN7LBVazirZYctOx Unyg== X-Gm-Message-State: APjAAAVKjdqe8cdl2nsnhmZPoTLkSKIe3w6gYGm6//TplDUC2hKhyLlG KbJyPdUp4q6rAyHIZSWPxo9KFA== X-Google-Smtp-Source: APXvYqzGNVeQ/R7JR9UNdXnpKZSm9sCG7ntxjETJuNIvtVXZ9l8S+gdw6OnN9egWqIdDF5D4ZyEZUA== X-Received: by 2002:a05:600c:22c8:: with SMTP id 8mr3940980wmg.178.1576685320145; Wed, 18 Dec 2019 08:08:40 -0800 (PST) Received: from myrica (adsl-84-227-176-239.adslplus.ch. [84.227.176.239]) by smtp.gmail.com with ESMTPSA id c5sm2949884wmb.9.2019.12.18.08.08.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 08:08:39 -0800 (PST) Date: Wed, 18 Dec 2019 17:08:34 +0100 From: Jean-Philippe Brucker To: Auger Eric Subject: Re: [PATCH v3 08/13] iommu/arm-smmu-v3: Propate ssid_bits Message-ID: <20191218160834.GG2371701@myrica> References: <20191209180514.272727-1-jean-philippe@linaro.org> <20191209180514.272727-9-jean-philippe@linaro.org> <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, linux-pci@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, robin.murphy@arm.com, linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org, robh+dt@kernel.org, guohanjun@huawei.com, bhelgaas@google.com, zhangfei.gao@linaro.org, will@kernel.org, linux-arm-kernel@lists.infradead.org, lenb@kernel.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 Tue, Dec 17, 2019 at 06:07:26PM +0100, Auger Eric wrote: > Hi Jean, > > On 12/9/19 7:05 PM, Jean-Philippe Brucker wrote: > > s/Propate/Propagate in the commit title. > > Now that we support substream IDs, initialize s1cdmax with the number of > > SSID bits supported by a master and the SMMU. > > > > Context descriptor tables are allocated once for the first master > > attached to a domain. Therefore attaching multiple devices with > > different SSID sizes is tricky, and we currently don't support it. > > > > As a future improvement it would be nice to at least support attaching a > > SSID-capable device to a domain that isn't using SSID, by reallocating > > the SSID table. > Isn't that use case relevant (I mean using both devices in a non SSID > use case). For platform devices you can work this around with FW but for > PCI devices? Normally each device gets its own domain. Especially since PASID is a PCI Express capability, I expect them to be properly isolated with ACS, each with its own IOMMU group. So I don't think this is too relevant for the moment, it would be a quirk for a broken system. 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 5CF2FC43603 for ; Wed, 18 Dec 2019 16:08:45 +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 3330C218AC for ; Wed, 18 Dec 2019 16:08:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="sXHPQCin"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="vGdwPfRl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3330C218AC 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=vZN8qt+4fpPRSaK0MeTT4wCgqQlwFUvrI180oM22giI=; b=sXHPQCinV95avQ WB5CR4VY0yMuzjcw4iJ4363VlBLbiiIUhxS8rlZNOFUb8garnpAU8kAx8b9jwp+OvSIhcfixrAGNk cfK8cqMuAW2ZfffCZepb6dFLsAtHitPYBeC6Add7qCqRjVMjdxK6FuHBDehTi0yNhDz2L10dDU8zY qnlrQI9f1ZMxm3l2/gTsYJ2x2VXclBGhvs1mli6DEhLu0D7LxvVMJqRky3y0k6Dh5wu7aflEQOzW4 jFXrDFSPhNDbSe+zMMbEpuweBFg2Z4Wf+cJ2HxfpRXewt1imFvGGu1jqAmB68x2VXvvMLS8JftSw7 Vf+tP0Qj4GdWYQ5X1GFQ==; 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 1ihbsS-0000DW-Jq; Wed, 18 Dec 2019 16:08:44 +0000 Received: from mail-wm1-x341.google.com ([2a00:1450:4864:20::341]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ihbsP-0000D4-Eb for linux-arm-kernel@lists.infradead.org; Wed, 18 Dec 2019 16:08:42 +0000 Received: by mail-wm1-x341.google.com with SMTP id 20so2393637wmj.4 for ; Wed, 18 Dec 2019 08:08:41 -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=o5X12+OnlTrR6hQB7btD1TwyQhH770WeXItNc7qt5zA=; b=vGdwPfRl1Ha9VhwGDZb29pGKHmrCLBjEh/aU/lWfjiA+Es/jr7ZphzP4HzPPmjTJx+ JSehVhXPNzXdOHN1KvgmcYfeFj+EOqqLkQfTn7w+aSzsmY9sA/Phabc6P4xORTt9/1CX ZeJvajjFb7Aa2pPQS2rmj8CC2WfmH3g8R6Icy6BCtWh0myJTrzSd94GfQGUovkp6jd2B rT+HoiZRDI9Poe0mNpRZQO9dQfwLmHSchdxzCs4OzzEO+QNZJtdaxkDjf9S6U0pGGXCC uBxrbddT9q0O1xSpIKLYhBMvxSFqGMIVi9YEcXDMHetlYODSFxx8S1+dGvzAMam0zV9q MZyA== 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=o5X12+OnlTrR6hQB7btD1TwyQhH770WeXItNc7qt5zA=; b=tLNsagelgBSHGo8mKhdzchL5z0jxpEy5pdVFCN7UlYpsmtFjJNlKeGJyvGFhGk30r6 cqp/30fesnQxFAVisoq//X44sQOlYNXorN6FEgFinaDfATpAPy1nlQ88PRGlauvkGkoo 3zYL17RJMg8VySSVlLP7oNIFLUXV2M0wiRN8N7yyuOTLt/ArWQmYHaqV574PRWLVbuCu q+dVugWpmsIZJGN1rSlO8fpiqrSqVgaGnFJdnyaPbmN5ucHhPaAStwNZ5iPtYky5mHQV EpGxnhkObSyZ/mDQ5dDzgkudOsFuGzOEBWFxfyfay2dxF1gT8BqsxhEweFyLvgpCNzga XMFw== X-Gm-Message-State: APjAAAW1nfsS5mlOL8IibdMtXelpaNU8dFWhj2eX42lQI4C3PtHXTCrm m5m1teZwPP1bp12VmivqbN7VlshSI2k= X-Google-Smtp-Source: APXvYqzGNVeQ/R7JR9UNdXnpKZSm9sCG7ntxjETJuNIvtVXZ9l8S+gdw6OnN9egWqIdDF5D4ZyEZUA== X-Received: by 2002:a05:600c:22c8:: with SMTP id 8mr3940980wmg.178.1576685320145; Wed, 18 Dec 2019 08:08:40 -0800 (PST) Received: from myrica (adsl-84-227-176-239.adslplus.ch. [84.227.176.239]) by smtp.gmail.com with ESMTPSA id c5sm2949884wmb.9.2019.12.18.08.08.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 08:08:39 -0800 (PST) Date: Wed, 18 Dec 2019 17:08:34 +0100 From: Jean-Philippe Brucker To: Auger Eric Subject: Re: [PATCH v3 08/13] iommu/arm-smmu-v3: Propate ssid_bits Message-ID: <20191218160834.GG2371701@myrica> References: <20191209180514.272727-1-jean-philippe@linaro.org> <20191209180514.272727-9-jean-philippe@linaro.org> <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191218_080841_493444_95B13E1A X-CRM114-Status: GOOD ( 14.16 ) 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: mark.rutland@arm.com, devicetree@vger.kernel.org, lorenzo.pieralisi@arm.com, linux-pci@vger.kernel.org, joro@8bytes.org, sudeep.holla@arm.com, rjw@rjwysocki.net, robin.murphy@arm.com, linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org, robh+dt@kernel.org, jonathan.cameron@huawei.com, guohanjun@huawei.com, bhelgaas@google.com, zhangfei.gao@linaro.org, will@kernel.org, linux-arm-kernel@lists.infradead.org, lenb@kernel.org 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 Tue, Dec 17, 2019 at 06:07:26PM +0100, Auger Eric wrote: > Hi Jean, > > On 12/9/19 7:05 PM, Jean-Philippe Brucker wrote: > > s/Propate/Propagate in the commit title. > > Now that we support substream IDs, initialize s1cdmax with the number of > > SSID bits supported by a master and the SMMU. > > > > Context descriptor tables are allocated once for the first master > > attached to a domain. Therefore attaching multiple devices with > > different SSID sizes is tricky, and we currently don't support it. > > > > As a future improvement it would be nice to at least support attaching a > > SSID-capable device to a domain that isn't using SSID, by reallocating > > the SSID table. > Isn't that use case relevant (I mean using both devices in a non SSID > use case). For platform devices you can work this around with FW but for > PCI devices? Normally each device gets its own domain. Especially since PASID is a PCI Express capability, I expect them to be properly isolated with ACS, each with its own IOMMU group. So I don't think this is too relevant for the moment, it would be a quirk for a broken system. Thanks, Jean _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel