From patchwork Thu May 7 03:32:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuppuswamy Sathyanarayanan X-Patchwork-Id: 11532365 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DEF1D15AB for ; Thu, 7 May 2020 03:33:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD0A92075A for ; Thu, 7 May 2020 03:33:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726267AbgEGDdI (ORCPT ); Wed, 6 May 2020 23:33:08 -0400 Received: from mga06.intel.com ([134.134.136.31]:39002 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725879AbgEGDdI (ORCPT ); Wed, 6 May 2020 23:33:08 -0400 IronPort-SDR: u+O5SXq0D1d4fJWDlUkBF7LDa2FoDuSaWGjvk7otAcJE7dehVbK9m3DLCKKe2ovvtkQ4ppDVDN Z3mQRouwUD1w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2020 20:33:07 -0700 IronPort-SDR: LLROTNw6PCNmZ27qFr0GAJ7AKDnxWByT4e3Rr6GTwB3Wk51WQBWovidx+E4jbvLYFQvQt1OPOH EpiFc/4YKy+A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,361,1583222400"; d="scan'208";a="249967520" Received: from cchia2-mobl1.amr.corp.intel.com (HELO localhost.localdomain) ([10.255.230.47]) by fmsmga007.fm.intel.com with ESMTP; 06 May 2020 20:33:06 -0700 From: sathyanarayanan.kuppuswamy@linux.intel.com To: bhelgaas@google.com Cc: jay.vosburgh@canonical.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ashok.raj@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: [PATCH v1 1/1] PCI/ERR: Handle fatal error recovery for non-hotplug capable devices Date: Wed, 6 May 2020 20:32:59 -0700 Message-Id: X-Mailer: git-send-email 2.17.1 In-Reply-To: <18609.1588812972@famine> References: <18609.1588812972@famine> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Kuppuswamy Sathyanarayanan If there are non-hotplug capable devices connected to a given port, then during the fatal error recovery(triggered by DPC or AER), after calling reset_link() function, we cannot rely on hotplug handler to detach and re-enumerate the device drivers in the affected bus. Instead, we will have to let the error recovery handler call report_slot_reset() for all devices in the bus to notify about the reset operation. Although this is only required for non hot-plug capable devices, doing it for hotplug capable devices should not affect the functionality. Along with above issue, this fix also applicable to following issue. Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") added support to store status of reset_link() call. Although this fixed the error recovery issue observed if the initial value of error status is PCI_ERS_RESULT_DISCONNECT or PCI_ERS_RESULT_NO_AER_DRIVER, it also discarded the status result from report_frozen_detected. This can cause a failure to recover if _NEED_RESET is returned by report_frozen_detected and report_slot_reset is not invoked. Such an event can be induced for testing purposes by reducing the Max_Payload_Size of a PCIe bridge to less than that of a device downstream from the bridge, and then initiating I/O through the device, resulting in oversize transactions. In the presence of DPC, this results in a containment event and attempted reset and recovery via pcie_do_recovery. After 6d2c89441571 report_slot_reset is not invoked, and the device does not recover. [original patch is from jay.vosburgh@canonical.com] [original patch link https://lore.kernel.org/linux-pci/18609.1588812972@famine/] Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") Signed-off-by: Jay Vosburgh Signed-off-by: Kuppuswamy Sathyanarayanan --- drivers/pci/pcie/err.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c index 14bb8f54723e..db80e1ecb2dc 100644 --- a/drivers/pci/pcie/err.c +++ b/drivers/pci/pcie/err.c @@ -165,13 +165,24 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, pci_dbg(dev, "broadcast error_detected message\n"); if (state == pci_channel_io_frozen) { pci_walk_bus(bus, report_frozen_detected, &status); - status = reset_link(dev); - if (status != PCI_ERS_RESULT_RECOVERED) { + status = PCI_ERS_RESULT_NEED_RESET; + } else { + pci_walk_bus(bus, report_normal_detected, &status); + } + + if (status == PCI_ERS_RESULT_NEED_RESET) { + if (reset_link) { + if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) + status = PCI_ERS_RESULT_DISCONNECT; + } else { + if (pci_bus_error_reset(dev)) + status = PCI_ERS_RESULT_DISCONNECT; + } + + if (status == PCI_ERS_RESULT_DISCONNECT) { pci_warn(dev, "link reset failed\n"); goto failed; } - } else { - pci_walk_bus(bus, report_normal_detected, &status); } if (status == PCI_ERS_RESULT_CAN_RECOVER) {