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=-10.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 A1F70C10F11 for ; Wed, 10 Apr 2019 16:04:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DFD920854 for ; Wed, 10 Apr 2019 16:04:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554912276; bh=4jYoZK+WAn/0HTad9YcD/I5hOYHYXCPL8X7Srb5aF14=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=CxppsAYglS44/g5aU/cRqmLNyV6Cj+DzCPUX0D3KDfTCZI+C4d6DuI9LYI2JdwkdI yxrfQ/BTtyZYatE7579wsJFIpwOEZX7gn7DYS/vBrEdyWDQ/NZQezSGVNVrkPgGUaC zcJ0psOSKrBkkPnZgpmV1o1tzHSx5NgEnyja8tJs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387622AbfDJQEg (ORCPT ); Wed, 10 Apr 2019 12:04:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:43340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727340AbfDJQEf (ORCPT ); Wed, 10 Apr 2019 12:04:35 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 8852A206DF; Wed, 10 Apr 2019 16:04:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554912274; bh=4jYoZK+WAn/0HTad9YcD/I5hOYHYXCPL8X7Srb5aF14=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=J0NTC1kYgbvQKdZipvVdhuA6Vb+44aGzxumpd3/QPRbY1wjJv63VeAu+Pwz2ZVE4M gE1NNf/aSFxag7kM93SDEbqGVnk96SC1GeSWD7EP93OBxnA7UUugslnls28lWhSJsV 7sz5WE8Al2I4kLQ9KzJtd6TcCX9f4q+FacoMgLtM= Date: Wed, 10 Apr 2019 12:04:32 -0400 From: Sasha Levin To: Jarkko Sakkinen Cc: robh+dt@kernel.org, mark.rutland@arm.com, peterhuewe@gmx.de, jgg@ziepe.ca, linux-kernel@microsoft.com, bryankel@microsoft.com, thiruan@microsoft.com, suredd@microsoft.com, arnd@arndb.de, gregkh@linuxfoundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org Subject: Re: [PATCH 2/2] ftpm: firmware TPM running in TEE Message-ID: <20190410160432.GB11568@sasha-vm> References: <20190402193316.15144-1-sashal@kernel.org> <20190402193316.15144-2-sashal@kernel.org> <20190403181827.GB17006@linux.intel.com> <20190403182728.GA17451@linux.intel.com> <20190406153047.GF2935@sasha-vm> <20190410112927.GA6586@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190410112927.GA6586@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Wed, Apr 10, 2019 at 02:29:27PM +0300, Jarkko Sakkinen wrote: >On Sat, Apr 06, 2019 at 11:30:47AM -0400, Sasha Levin wrote: >> On Wed, Apr 03, 2019 at 09:27:28PM +0300, Jarkko Sakkinen wrote: >> > On Wed, Apr 03, 2019 at 09:18:27PM +0300, Jarkko Sakkinen wrote: >> > > On Tue, Apr 02, 2019 at 03:33:16PM -0400, Sasha Levin wrote: >> > > > This patch adds support for a software-only implementation of a TPM >> > > > running in TEE. >> > > > >> > > > There is extensive documentation of the design here: >> > > > https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ . >> > > > >> > > > As well as reference code for the firmware available here: >> > > > https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM >> > > > >> > > > Signed-off-by: Thirupathaiah Annapureddy >> > > > Signed-off-by: Sasha Levin >> > > >> > > What is the context anyway? I mean tpm_crb already supports fTPM running >> > > in TZ. >> > >> > Might take 2-3 weeks before I have time to go through ftpm1.pdf with >> > full concentration. I did search through the PDF for CRB and found >> > zero hits. >> >> The fTPM as described in that paper and implemented in practice does not >> use the CRB interface, thus we can't use tpm_crb to interface with the >> firmware TPM. > >Obviously not but what is the reason of not implementing CRB but instead >making yet another interface? I mean CRB supports SMC call. > >For me this is taking steps back as to the early days when there was >proprietary intefaces to TPM before TCG came along and stardized. > >I'm sure that the TPM implementation itself could be reworked to >inteface using CRB. It would also be good for ARM as a platform as now >this new made up interface causes unwanted divergence. I thought that >throwing ad hoc intefaces everywhere is something that ARM Linux >community tries to reduce, not increase. I'm not sure what the original reasons were for not using the CRB interface. Note that the paper is from a few years ago, and implementations of this fTPM existed before the paper, so it's very possible that it just predates CRB. Either way, there is existing hardware that runs this TPM and I'm trying to get it out of Microsoft's tree and get it upstream. There's not much I could do about existing hardware at this point. -- Thanks, Sasha