From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 5/5] PCI: disable FLR for 82579 device Date: Thu, 22 Sep 2016 23:39:01 -0700 Message-ID: <1474612741-75681-6-git-send-email-jeffrey.t.kirsher@intel.com> References: <1474612741-75681-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Sasha Neftin , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com, guru.anbalagane@oracle.com, linux-pci@vger.kernel.org, Jeff Kirsher To: davem@davemloft.net, bhelgaas@google.com Return-path: Received: from mga01.intel.com ([192.55.52.88]:24714 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932636AbcIWGjG (ORCPT ); Fri, 23 Sep 2016 02:39:06 -0400 In-Reply-To: <1474612741-75681-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Sasha Neftin 82579 has a problem reattaching itself after the device is detached. The bug was reported by Redhat. The suggested fix is to disable FLR capability in PCIe configuration space. Reproduction: Attach the device to a VM, then detach and try to attach again. Fix: Disable FLR capability to prevent the 82579 from hanging. Signed-off-by: Sasha Neftin Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher --- drivers/pci/quirks.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 44e0ff3..59fba6e 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4431,3 +4431,24 @@ static void quirk_intel_qat_vf_cap(struct pci_dev *pdev) } } DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x443, quirk_intel_qat_vf_cap); +/* + * Workaround FLR issues for 82579 + * This code disables the FLR (Function Level Reset) via PCIe, in order + * to workaround a bug found while using device passthrough, where the + * interface would become non-responsive. + * NOTE: the FLR bit is Read/Write Once (RWO) in config space, so if + * the BIOS or kernel writes this register * then this workaround will + * not work. + */ +static void quirk_intel_flr_cap_dis(struct pci_dev *dev) +{ + int pos = pci_find_capability(dev, PCI_CAP_ID_AF); + if (pos) { + u8 cap; + pci_read_config_byte(dev, pos + PCI_AF_CAP, &cap); + cap = cap & (~PCI_AF_CAP_FLR); + pci_write_config_byte(dev, pos + PCI_AF_CAP, cap); + } +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1502, quirk_intel_flr_cap_dis); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1503, quirk_intel_flr_cap_dis); -- 2.7.4