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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D6FB7C3F2D1 for ; Mon, 2 Mar 2020 11:11:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B61E421D56 for ; Mon, 2 Mar 2020 11:11:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726448AbgCBLLU (ORCPT ); Mon, 2 Mar 2020 06:11:20 -0500 Received: from mga04.intel.com ([192.55.52.120]:24667 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725996AbgCBLLU (ORCPT ); Mon, 2 Mar 2020 06:11:20 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Mar 2020 03:11:19 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,506,1574150400"; d="scan'208";a="412243946" Received: from aorourk1-mobl.ger.corp.intel.com (HELO localhost) ([10.251.86.123]) by orsmga005.jf.intel.com with ESMTP; 02 Mar 2020 03:11:17 -0800 Date: Mon, 2 Mar 2020 13:11:16 +0200 From: Jarkko Sakkinen To: Stefan Berger Cc: linux-integrity@vger.kernel.org, aik@ozlabs.ru, david@gibson.dropbear.id.au, linux-kernel@vger.kernel.org, nayna@linux.vnet.ibm.com, gcwilson@linux.ibm.com, jgg@ziepe.ca, Stefan Berger Subject: Re: [PATCH v5 2/3] tpm: ibmvtpm: Wait for buffer to be set before proceeding Message-ID: <20200302111116.GB3979@linux.intel.com> References: <20200228030330.18081-1-stefanb@linux.vnet.ibm.com> <20200228030330.18081-3-stefanb@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200228030330.18081-3-stefanb@linux.vnet.ibm.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo 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 Thu, Feb 27, 2020 at 10:03:29PM -0500, Stefan Berger wrote: > From: Stefan Berger > > Synchronize with the results from the CRQs before continuing with > the initialization. This avoids trying to send TPM commands while > the rtce buffer has not been allocated, yet. > > This patch fixes an existing race condition that may occurr if the > hypervisor does not quickly respond to the VTPM_GET_RTCE_BUFFER_SIZE > request sent during initialization and therefore the ibmvtpm->rtce_buf > has not been allocated at the time the first TPM command is sent. > > Fixes: 132f76294744 ("Add new device driver to support IBM vTPM") > Signed-off-by: Stefan Berger > --- > drivers/char/tpm/tpm_ibmvtpm.c | 9 +++++++++ > drivers/char/tpm/tpm_ibmvtpm.h | 1 + > 2 files changed, 10 insertions(+) > > diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c > index 78cc52690177..eee566eddb35 100644 > --- a/drivers/char/tpm/tpm_ibmvtpm.c > +++ b/drivers/char/tpm/tpm_ibmvtpm.c > @@ -571,6 +571,7 @@ static irqreturn_t ibmvtpm_interrupt(int irq, void *vtpm_instance) > */ > while ((crq = ibmvtpm_crq_get_next(ibmvtpm)) != NULL) { > ibmvtpm_crq_process(crq, ibmvtpm); > + wake_up_interruptible(&ibmvtpm->crq_queue.wq); > crq->valid = 0; > smp_wmb(); > } > @@ -618,6 +619,7 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev, > } > > crq_q->num_entry = CRQ_RES_BUF_SIZE / sizeof(*crq_q->crq_addr); > + init_waitqueue_head(&crq_q->wq); > ibmvtpm->crq_dma_handle = dma_map_single(dev, crq_q->crq_addr, > CRQ_RES_BUF_SIZE, > DMA_BIDIRECTIONAL); > @@ -670,6 +672,13 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev, > if (rc) > goto init_irq_cleanup; > > + if (!wait_event_timeout(ibmvtpm->crq_queue.wq, > + ibmvtpm->rtce_buf != NULL, > + HZ)) { > + dev_err(dev, "Initialization failed\n"); I'd change this something more descriptive "CRQ response timed out". /Jarkko