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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 B8808C433EF for ; Tue, 19 Jun 2018 13:10:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7BDB62083D for ; Tue, 19 Jun 2018 13:10:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BDB62083D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937814AbeFSNKy (ORCPT ); Tue, 19 Jun 2018 09:10:54 -0400 Received: from mga14.intel.com ([192.55.52.115]:15438 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937703AbeFSNKw (ORCPT ); Tue, 19 Jun 2018 09:10:52 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Jun 2018 06:10:52 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,243,1526367600"; d="scan'208";a="50514883" Received: from aluisell-mobl2.ger.corp.intel.com (HELO localhost) ([10.249.254.128]) by orsmga008.jf.intel.com with ESMTP; 19 Jun 2018 06:10:47 -0700 Date: Tue, 19 Jun 2018 16:10:46 +0300 From: Jarkko Sakkinen To: Tadeusz Struk Cc: jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, philip.b.tricca@intel.com, James.Bottomley@HansenPartnership.com Subject: Re: [PATCH v3 0/2] tpm: add support for nonblocking operation Message-ID: <20180619131046.GC5609@linux.intel.com> References: <152882630662.30206.8805136953394285180.stgit@tstruk-mobl1.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <152882630662.30206.8805136953394285180.stgit@tstruk-mobl1.jf.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 12, 2018 at 10:58:26AM -0700, Tadeusz Struk wrote: > The TCG SAPI specification [1] defines a set of functions, which allows > applications to use the TPM device in either blocking or non-blocking fashion. > Each command defined by the specification has a corresponding > Tss2_Sys__Prepare() and Tss2_Sys__Complete() call, which > together with Tss2_Sys_ExecuteAsync() is designed to allow asynchronous > mode of operation. Currently the TPM driver supports only blocking calls, > which doesn't allow asynchronous IO operations. > This patch changes it and adds support for nonblocking write and a new poll > function to enable applications, which want to take advantage of this feature. > The new functionality can be tested using standard TPM tools implemented > in [2], together with modified TCTI from [3]. > > [1] https://trustedcomputinggroup.org/wp-content/uploads/TSS_SAPI_Version-1.1_Revision-22_review_030918.pdf > [2] https://github.com/tpm2-software/tpm2-tools > [3] https://github.com/tstruk/tpm2-tss/tree/async For me the value is still a bit questionable. The benchmark looks a bit flakky to give much figures how this would work with real world workloads. I read James response and I also have to question why not just a worker thread in user space? TPM does only one command at a time anyways. Cannot take this in before I know that user space will (1) adapt to this and (2) gain value compared to a worker thread. /Jarkko