Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752895AbaLNUlO (ORCPT ); Sun, 14 Dec 2014 15:41:14 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:58354 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752448AbaLNUkP (ORCPT ); Sun, 14 Dec 2014 15:40:15 -0500 Message-ID: <548DF5A5.2080500@linux.vnet.ibm.com> Date: Sun, 14 Dec 2014 15:40:05 -0500 From: Stefan Berger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Scot Doyle CC: Jarkko Sakkinen , Peter Huewe , Ashley Lai , Marcel Selhorst , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, josh@joshtriplett.org, christophe.ricard@gmail.com, jason.gunthorpe@obsidianresearch.com, Will Arthur Subject: Re: [PATCH v10 8/8] tpm: TPM 2.0 FIFO Interface References: <1418413600-5400-1-git-send-email-jarkko.sakkinen@linux.intel.com> <1418413600-5400-9-git-send-email-jarkko.sakkinen@linux.intel.com> <548DA33A.4010300@linux.vnet.ibm.com> <20141214154003.GA13338@intel.com> <548DB62E.7060504@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14121420-0021-0000-0000-000006F1BDF1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/14/2014 01:27 PM, Scot Doyle wrote: > On Sun, 14 Dec 2014, Stefan Berger wrote: >> On 12/14/2014 10:40 AM, Jarkko Sakkinen wrote: >>> On Sun, Dec 14, 2014 at 09:48:26AM -0500, Stefan Berger wrote: >>>> On 12/12/2014 02:46 PM, Jarkko Sakkinen wrote: >>>>> Detect TPM 2.0 by sending idempotent TPM 2.x command. Ordinals for >>>>> TPM 2.0 are higher than TPM 1.x commands so this should be fail-safe. >>>>> Using STS3 is unreliable because some chips just report 0xff and not >>>>> what the spec says. >>>> TPM TIS 1.2 can report either 0xff or 0x00 for sts3 since that part of >>>> register was not defined for this version but only for a later version. >>>> So, >>>> unless the TIS 1.3 for TPM 2.0 is broken, it should report a bit _pattern_ >>>> (not plain 0x00 or 0xff) that you could apply the suggested mask to and >>>> check then. >>> I propose this: lets keep the bit ugly but approach for now and when >>> there are TPM2 FIFOs available in the market move to your workaround. >>> I think that would be the most reasonable middle road here. >> You are now calling tpm2_gen_interrupt and are looking at the rc, which is the >> rc from tpm_transmit_cmd, which seems to make sure that the sending of the >> command went alright and the reception of the response. Is this good enough to >> distinguish between a TPM 2 and a TPM 1.2? If you send a valid TPM 2 command >> to a TPM 1.2 this will at least transmit the data ok, but the TPM will respond >> with a TPM 1.2 tag in the response. The way I understand the code, the rc does >> not include whether the response packet is a valid TPM 2 response packet and >> lets you conclude to a TPM2. I do something similar in upcoming QEMU patches >> where I send a valid TPM2 command for probing and if the tag(!) in the >> response is a TPM2 tag (0x8001 = TPM_ST_NO_SESSIONS), then it's a TPM 2, >> otherwise a TPM 1.2. >> >> Did you test this with a TPM 1.2 ? >> >> Stefan > One system's output, with a dev_info call to show the value of rc: > [ 0.223837] tpm_tis 00:08: tpm2_gen_interrupt(chip, true) -> 0xa > [ 0.223847] tpm_tis 00:08: 1.2 TPM (device-id 0xB, rev-id 16) > [ 0.280468] tpm_tis 00:08: [Firmware Bug]: TPM interrupt not working, polling instead > Ok, good. [We won't be able to use STS3 if the TIS of Jarkko's TPM2 is broken...] Stefan Stefan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/