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[209.132.180.67]) by mx.google.com with ESMTP id v21si1944415pgo.897.2017.08.05.00.19.35; Sat, 05 Aug 2017 00:19:36 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752140AbdHEHTc (ORCPT + 25 others); Sat, 5 Aug 2017 03:19:32 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:11261 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751161AbdHEHSO (ORCPT ); Sat, 5 Aug 2017 03:18:14 -0400 Received: from 172.30.72.57 (EHLO DGGEML404-HUB.china.huawei.com) ([172.30.72.57]) by dggrg01-dlp.huawei.com (MOS 4.4.6-GA FastPath queued) with ESMTP id ATX06105; Sat, 05 Aug 2017 15:17:59 +0800 (CST) Received: from localhost (10.177.23.32) by DGGEML404-HUB.china.huawei.com (10.3.17.39) with Microsoft SMTP Server id 14.3.301.0; Sat, 5 Aug 2017 15:17:49 +0800 From: Ding Tianhong To: , , , , , , , , , , , , , , , , , , , , , , , , , CC: Ding Tianhong Subject: [PATCH v9 2/4] PCI: Disable PCIe Relaxed Ordering if unsupported Date: Sat, 5 Aug 2017 15:15:11 +0800 Message-ID: <1501917313-9812-3-git-send-email-dingtianhong@huawei.com> X-Mailer: git-send-email 1.8.5.2.msysgit.0 In-Reply-To: <1501917313-9812-1-git-send-email-dingtianhong@huawei.com> References: <1501917313-9812-1-git-send-email-dingtianhong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.177.23.32] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.59857128.0024, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 1a52276e3d82eccb1db42fbdc318396d Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When bit4 is set in the PCIe Device Control register, it indicates whether the device is permitted to use relaxed ordering. On some platforms using relaxed ordering can have performance issues or due to erratum can cause data-corruption. In such cases devices must avoid using relaxed ordering. This patch checks if there is any node in the hierarchy that indicates that using relaxed ordering is not safe. In such cases the patch turns off the relaxed ordering by clearing the eapability for this device. And if the device is probably running in a guest machine, we should do nothing. Signed-off-by: Ding Tianhong Acked-by: Alexander Duyck Acked-by: Ashok Raj --- drivers/pci/pci.c | 29 +++++++++++++++++++++++++++++ drivers/pci/probe.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 2 ++ 3 files changed, 68 insertions(+) -- 1.8.3.1 diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af0cc34..4f9d7c1 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4854,6 +4854,35 @@ int pcie_set_mps(struct pci_dev *dev, int mps) EXPORT_SYMBOL(pcie_set_mps); /** + * pcie_clear_relaxed_ordering - clear PCI Express relaxed ordering bit + * @dev: PCI device to query + * + * If possible clear relaxed ordering + */ +int pcie_clear_relaxed_ordering(struct pci_dev *dev) +{ + return pcie_capability_clear_word(dev, PCI_EXP_DEVCTL, + PCI_EXP_DEVCTL_RELAX_EN); +} +EXPORT_SYMBOL(pcie_clear_relaxed_ordering); + +/** + * pcie_relaxed_ordering_supported - Probe for PCIe relexed ordering support + * @dev: PCI device to query + * + * Returns true if the device support relaxed ordering attribute. + */ +bool pcie_relaxed_ordering_supported(struct pci_dev *dev) +{ + u16 v; + + pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &v); + + return !!(v & PCI_EXP_DEVCTL_RELAX_EN); +} +EXPORT_SYMBOL(pcie_relaxed_ordering_supported); + +/** * pcie_get_minimum_link - determine minimum link settings of a PCI device * @dev: PCI device to query * @speed: storage for minimum speed diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index c31310d..48df012 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1762,6 +1762,42 @@ static void pci_configure_extended_tags(struct pci_dev *dev) PCI_EXP_DEVCTL_EXT_TAG); } +/** + * pci_dev_should_disable_relaxed_ordering - check if the PCI device + * should disable the relaxed ordering attribute. + * @dev: PCI device + * + * Return true if any of the PCI devices above us do not support + * relaxed ordering. + */ +static bool pci_dev_should_disable_relaxed_ordering(struct pci_dev *dev) +{ + while (dev) { + if (dev->dev_flags & PCI_DEV_FLAGS_NO_RELAXED_ORDERING) + return true; + + dev = dev->bus->self; + } + + return false; +} + +static void pci_configure_relaxed_ordering(struct pci_dev *dev) +{ + /* We should not alter the relaxed ordering bit for the VF */ + if (dev->is_virtfn) + return; + + /* If the releaxed ordering enable bit is not set, do nothing. */ + if (!pcie_relaxed_ordering_supported(dev)) + return; + + if (pci_dev_should_disable_relaxed_ordering(dev)) { + pcie_clear_relaxed_ordering(dev); + dev_info(&dev->dev, "Disable Relaxed Ordering\n"); + } +} + static void pci_configure_device(struct pci_dev *dev) { struct hotplug_params hpp; @@ -1769,6 +1805,7 @@ static void pci_configure_device(struct pci_dev *dev) pci_configure_mps(dev); pci_configure_extended_tags(dev); + pci_configure_relaxed_ordering(dev); memset(&hpp, 0, sizeof(hpp)); ret = pci_get_hp_params(dev, &hpp); diff --git a/include/linux/pci.h b/include/linux/pci.h index 412ec1c..3aa23a2 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1127,6 +1127,8 @@ int pci_add_ext_cap_save_buffer(struct pci_dev *dev, void pci_pme_wakeup_bus(struct pci_bus *bus); void pci_d3cold_enable(struct pci_dev *dev); void pci_d3cold_disable(struct pci_dev *dev); +int pcie_clear_relaxed_ordering(struct pci_dev *dev); +bool pcie_relaxed_ordering_supported(struct pci_dev *dev); /* PCI Virtual Channel */ int pci_save_vc_state(struct pci_dev *dev);