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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 B35AFC64E7B for ; Mon, 30 Nov 2020 11:19:07 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 2FDC92076E for ; Mon, 30 Nov 2020 11:19:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="DIU9G3W/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2FDC92076E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.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=wHPwXABiWaxOFwOs5u80YiSAkTUDLWw6b4wi41tf/5E=; b=DIU9G3W/pZmrhUOIPQvHC9UBu xq4m8AzQtqrN9lzCjqblq/Kya17Ty0OeHw1Yf5A+/TYGeWo11C7RWkemnicvpFpJBtFBRLnTHF1ZY jYA8CDN+dRTIWbe7X3JsT9XDSuDJeBMbqE9vsMKvP/4JhRz1aiuaYOExXtVXuRXKKkVUCxUPbivTY kGclvrmBQIddLWa5w6HCUKaPzh47g3NTtkheSzjLgJmiX5qWitQ4roMRXPCmyZ8Q+Wonmez36jEqU NDlIzR1zjMLolNg85AW9ePxELMqZ5ca9FxB97aaW5D4kjlNpb8cWqv9DbSjfg8HNkQvh3CPRIkY5g aEz2w20ig==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kjhBw-0002VK-Hx; Mon, 30 Nov 2020 11:18:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kjhBt-0002Uh-61 for linux-arm-kernel@lists.infradead.org; Mon, 30 Nov 2020 11:17:58 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CCB101042; Mon, 30 Nov 2020 03:17:55 -0800 (PST) Received: from bogus (unknown [10.57.62.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3F7593F66B; Mon, 30 Nov 2020 03:17:53 -0800 (PST) Date: Mon, 30 Nov 2020 11:17:50 +0000 From: Sudeep Holla To: Jens Wiklander Subject: Re: [PATCH v2 0/9] firmware: Add initial support for Arm FF-A Message-ID: <20201130111750.uiws2f2neygs7qrg@bogus> References: <20201103174350.991593-1-sudeep.holla@arm.com> <20201128122502.GA8649@jade> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201128122502.GA8649@jade> User-Agent: NeoMutt/20171215 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201130_061757_280446_F8E77603 X-CRM114-Status: GOOD ( 26.87 ) 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: Trilok Soni , devicetree@vger.kernel.org, David Hartley , Andrew Walbran , Achin Gupta , arve@android.com, Trilok Soni , Fuad Tabba , Android Kernel Team , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Nov 28, 2020 at 01:25:02PM +0100, Jens Wiklander wrote: > Hi Sudeep, > > On Tue, Nov 03, 2020 at 05:43:41PM +0000, Sudeep Holla wrote: > > Hi all, > > > > Let me start stating this is just initial implementation to check on > > the idea of providing more in-kernel and userspace support. Lot of things > > are still work in progress, I am posting just to get the early feedback > > before building lot of things on this idea. Consider this more as RFC > > though not tagged explicity(just to avoid it being ignored :)) > > > > Arm Firmware Framework for Armv8-A specification[1] describes a software > > architecture that provides mechanism to utilise the virtualization > > extension to isolate software images and describes interfaces that > > standardize communication between the various software images. This > > includes communication between images in the Secure and Normal world. > > > > The main idea here is to create FFA device to establish any communication > > with a partition(secure or normal world VM). > > > > If it is a partition managed by hypervisor, then we will register chardev > > associated with each of those partition FFA device. > > > > /dev/arm_ffa: > > > > e3a48fa5-dc54-4a8b-898b-bdc4dfeeb7b8 > > 49f65057-d002-4ae2-b4ee-d31c7940a13d > > > > For in-kernel usage(mostly communication with secure partitions), only > > in-kernel APIs are accessible(no userspace). There may be a need to > > provide userspace access instead of in-kernel, it is not yet support > > in this series as we need way to identify those and I am not sure if > > that belong to DT. > > With unfiltered VM to VM commnication from user space there's no easy > way for two VMs to exchange privileged information that excludes user > space. Though this usercase is dropped now, it was targeted for VMM and may be it was not an issue there. > Perhaps access to the FFA device is considered privileged and > enough for all purposes. > I don't know TBH. > If I've understood it correctly is VM to SP communication only allowed > via kernel mode in the VM. Correct. > The communication with OP-TEE depends on this with the recent commit > c5b4312bea5d ("tee: optee: Add support for session login client UUID > generation"). > OK, thanks for the info. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel