From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id C58647F38D for ; Mon, 8 Jul 2019 15:54:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388644AbfGHPZj (ORCPT ); Mon, 8 Jul 2019 11:25:39 -0400 Received: from mga07.intel.com ([134.134.136.100]:18169 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388641AbfGHPZj (ORCPT ); Mon, 8 Jul 2019 11:25:39 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jul 2019 08:25:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,466,1557212400"; d="scan'208";a="363835132" Received: from jsakkine-mobl1.tm.intel.com ([10.237.50.189]) by fmsmga005.fm.intel.com with ESMTP; 08 Jul 2019 08:25:35 -0700 Message-ID: <846cacae8cede764a2e84f628f539d94582fdbe0.camel@linux.intel.com> Subject: Re: [PATCH] tpm: Document UEFI event log quirks From: Jarkko Sakkinen To: Randy Dunlap , linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-doc@vger.kernel.org Cc: tweek@google.com, matthewgarrett@google.com, Jonathan Corbet Date: Mon, 08 Jul 2019 18:25:38 +0300 In-Reply-To: References: <20190703161109.22935-1-jarkko.sakkinen@linux.intel.com> <6acf78df-b168-14d3-fea4-9a9d2945e77f@infradead.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Sun, 2019-07-07 at 12:33 -0700, Randy Dunlap wrote: > On 7/5/19 3:15 AM, Jarkko Sakkinen wrote: > > On Wed, 2019-07-03 at 09:45 -0700, Randy Dunlap wrote: > > > > +This introduces another problem: nothing guarantees that it is not > > > > +called before the stub gets to run. Thus, it needs to copy the final > > > > +events table preboot size to the custom configuration table so that > > > > +kernel offset it later on. > > (so that) > the kernel can use that final table preboot size as an events table > offset later on. > > > > ? kernel can offset it later on. > > > > EFI stub calculates the total size of the events in the final events > > table at the time. > > > > Later on, TPM driver uses this offset to copy only the events that > > were actually generated after ExitBootServices(): > > > > /* > > * Copy any of the final events log that didn't also end up in the > > * main log. Events can be logged in both if events are generated > > * between GetEventLog() and ExitBootServices(). > > */ > > memcpy((void *)log->bios_event_log + log_size, > > final_tbl->events + log_tbl->final_events_preboot_size, > > efi_tpm_final_log_size); > > > > What would be a better way to describe this? > > Yeah, I think I see what it's doing, how it's using that. > See above. > > OK? Your propsal looks legit, thank you. I'll send an update that tries to address yours and Jordan's feedback. /Jarkko