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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 34655C433E1 for ; Thu, 11 Jun 2020 17:12:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2A6A20829 for ; Thu, 11 Jun 2020 17:12:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591895550; bh=+n3fYC/9iagTFJHZVyX/Y73W3bVcAjcHk8YWZHr8tLw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=g3b0VlYd9Y2UY2IjalySappkZerWwIZRVhxGjldS4RmO4zY+LqDLCqPj7nDLkAVX5 tRvBnBVvFukIEgMTzGReBXZ3Te18WtvLmhn0RQovbn64CXfziv9i/Bwqf1i7RQ37yH 2xu2zeyriNFyYNxicK8T9dTM3QOj3H5g8zvG2Uj0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726755AbgFKRM2 (ORCPT ); Thu, 11 Jun 2020 13:12:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:40474 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726379AbgFKRM2 (ORCPT ); Thu, 11 Jun 2020 13:12:28 -0400 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4EC3C207ED; Thu, 11 Jun 2020 17:12:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591895547; bh=+n3fYC/9iagTFJHZVyX/Y73W3bVcAjcHk8YWZHr8tLw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WIYDmLV4pQ+VScpZK0j6FfcLG6yCMFfeNXbPGe37mo6Gd9wKibO+6WRRvordXe/y4 b7RQfeNTNqboZp5k3o+YrkhuZgJW74VUEkPUofs2X+5C1xQFBV7AFodxsqZ+0G3eS+ fYY8Ebx5XUE43Tmfz2xVOmZYnDDblbkkGOKYq78g= Date: Thu, 11 Jun 2020 18:12:23 +0100 From: Will Deacon To: Achin Gupta Cc: Rob Herring , Sudeep Holla , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Marc Zyngier , nd Subject: Re: [RFC PATCH 1/3] dt-bindings: Add ARM PSA FF binding for non-secure VM partitions Message-ID: <20200611171222.GB7725@willie-the-truck> References: <20200601094512.50509-1-sudeep.holla@arm.com> <20200601094512.50509-2-sudeep.holla@arm.com> <20200609223551.GA1620273@bogus> <20200610074346.GB15939@willie-the-truck> <5B3F18A4-5DA4-411E-9E26-7D25DEE3D414@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5B3F18A4-5DA4-411E-9E26-7D25DEE3D414@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 11, 2020 at 03:46:35PM +0000, Achin Gupta wrote: > > On 10 Jun 2020, at 08:43, Will Deacon wrote: > > On Tue, Jun 09, 2020 at 04:35:51PM -0600, Rob Herring wrote: > >> On Mon, Jun 01, 2020 at 10:45:10AM +0100, Sudeep Holla wrote: > >>> Add devicetree bindings for a Arm PSA FF-A compliant non-secure partition > >>> at virtual interface(VMs). > >>> > >>> Signed-off-by: Sudeep Holla > >>> --- > >>> .../devicetree/bindings/arm/arm,psa-ffa.txt | 47 +++++++++++++++++++ > >>> 1 file changed, 47 insertions(+) > >>> create mode 100644 Documentation/devicetree/bindings/arm/arm,psa-ffa.txt > >> > >> I'm hoping this goes away if the firmware is discoverable, but if not DT > >> bindings are DT schema now. > > > > We'll need the binding for the kvm host side, because there are plenty > > of partition properties that are not discoverable (e.g. number of vCPUs). > > Just trying to understand the req. a bit better… > > The FF-A driver in the host can use FFA_PARTITION_INFO_GET to determine > the count of partitions and their vCPUs. > > Is this about a guest being able to find out how many vCPUs it has? This is about KVM finding out the information it needs in order to spawn non-secure partitions. I don't see how it can do that with FFA_PARTITION_INFO_GET -- who would respond? But you're right that number of vCPUs was a bad example. We also need information such as the entry point. Will