From patchwork Fri Jun 7 16:34:47 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 2688281 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 99A3940079 for ; Fri, 7 Jun 2013 16:35:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756648Ab3FGQeu (ORCPT ); Fri, 7 Jun 2013 12:34:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33468 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756469Ab3FGQet (ORCPT ); Fri, 7 Jun 2013 12:34:49 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r57GYmUS015141 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 7 Jun 2013 12:34:48 -0400 Received: from bling.home ([10.3.113.6]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r57GYl8h007248; Fri, 7 Jun 2013 12:34:47 -0400 Subject: [PATCH v2 2/2] pci: Differentiate ACS controllable from enabled To: bhelgaas@google.com From: Alex Williamson Cc: linux-pci@vger.kernel.org, ddutile@redhat.com, linux-kernel@vger.kernel.org Date: Fri, 07 Jun 2013 10:34:47 -0600 Message-ID: <20130607163447.7733.70375.stgit@bling.home> In-Reply-To: <20130607162732.7733.17758.stgit@bling.home> References: <20130607162732.7733.17758.stgit@bling.home> User-Agent: StGit/0.16 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org We currently misinterpret that in order for an ACS feature to be enabled it must be set in the control field. In reality, this means that the feature is not only enabled, but controllable. Many of the ACS capability bits are not required if the device behaves by default in the way specified when both the capability and control bit are set and does not support or allow the alternate mode. We therefore need to check the capabilities and mask out flags that are enabled but not controllable. Egress control seems to be the only flag which is purely optional. Signed-off-by: Alex Williamson --- drivers/pci/pci.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 457ae51..8b8504c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2357,12 +2357,20 @@ void pci_enable_acs(struct pci_dev *dev) static bool pci_acs_flags_enabled(struct pci_dev *pdev, u16 acs_flags) { int pos; - u16 ctrl; + u16 cap, ctrl; pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS); if (!pos) return false; + /* + * Except for egress control, capabilities are either required + * or only required if controllable. Features missing from the + * capability field can therefore be assumed as hard-wired enabled. + */ + pci_read_config_word(pdev, pos + PCI_ACS_CAP, &cap); + acs_flags &= (cap | PCI_ACS_EC); + pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl); return (ctrl & acs_flags) == acs_flags; } @@ -2412,9 +2420,6 @@ bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags) if (!pdev->multifunction) break; - acs_flags &= (PCI_ACS_RR | PCI_ACS_CR | - PCI_ACS_EC | PCI_ACS_DT); - return pci_acs_flags_enabled(pdev, acs_flags); }