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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 6F710C2D0CD for ; Wed, 18 Dec 2019 17:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43C27227BF for ; Wed, 18 Dec 2019 17:00:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ItGxrXOf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727440AbfLRRAn (ORCPT ); Wed, 18 Dec 2019 12:00:43 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:57112 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727173AbfLRRAn (ORCPT ); Wed, 18 Dec 2019 12:00:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576688442; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dn5SUwiPZ6v5NQ8mtwG6iqV/r/5Gbbs8HrzPzH1EerI=; b=ItGxrXOflq3XyLIwUJF7tFGtxNAtXEZvoJAqtOQ8q+t4Z7s9krV+q06Ts5M9DKXW1CBzPU agL7aGhiuJwVchL9v7JxPXOgWH5wVBcgrqXkEfqei7IugImk2h4LzKrvvEG+ju9FXxeKXT Ncvjlv+uMS2lQ3/c1dvaa/IM9Dcdrpo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-352-9UUkOd8SOmCuHuHDl5aHpg-1; Wed, 18 Dec 2019 12:00:18 -0500 X-MC-Unique: 9UUkOd8SOmCuHuHDl5aHpg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 797B119586C8; Wed, 18 Dec 2019 17:00:14 +0000 (UTC) Received: from [10.36.116.117] (ovpn-116-117.ams2.redhat.com [10.36.116.117]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1A81460C18; Wed, 18 Dec 2019 17:00:09 +0000 (UTC) Subject: Re: [PATCH v3 08/13] iommu/arm-smmu-v3: Propate ssid_bits To: Jean-Philippe Brucker 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 References: <20191209180514.272727-1-jean-philippe@linaro.org> <20191209180514.272727-9-jean-philippe@linaro.org> <466bbc57-79d4-274c-67bc-4ed591da9968@redhat.com> <20191218160834.GG2371701@myrica> From: Auger Eric Message-ID: Date: Wed, 18 Dec 2019 18:00:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20191218160834.GG2371701@myrica> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Jean, On 12/18/19 5:08 PM, Jean-Philippe Brucker wrote: > 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. OK Eric > > Thanks, > Jean >