From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753684AbcFEVn4 (ORCPT ); Sun, 5 Jun 2016 17:43:56 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43068 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753563AbcFEVm6 (ORCPT ); Sun, 5 Jun 2016 17:42:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Gavin Shan , Russell Currey , Michael Ellerman Subject: [PATCH 4.4 68/99] powerpc/eeh: Restore initial state in eeh_pe_reset_and_recover() Date: Sun, 5 Jun 2016 14:41:41 -0700 Message-Id: <20160605213909.607085136@linuxfoundation.org> X-Mailer: git-send-email 2.8.3 In-Reply-To: <20160605213902.974592018@linuxfoundation.org> References: <20160605213902.974592018@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gavin Shan commit 5a0cdbfd17b90a89c64a71d8aec9773ecdb20d0d upstream. The function eeh_pe_reset_and_recover() is used to recover EEH error when the passthrou device are transferred to guest and backwards. The content in the device's config space will be lost on PE reset issued in the middle of the recovery. The function saves/restores it before/after the reset. However, config access to some adapters like Broadcom BCM5719 at this point will causes fenced PHB. The config space is always blocked and we save 0xFF's that are restored at late point. The memory BARs are totally corrupted, causing another EEH error upon access to one of the memory BARs. This restores the config space on those adapters like BCM5719 from the content saved to the EEH device when it's populated, to resolve above issue. Fixes: 5cfb20b9 ("powerpc/eeh: Emulate EEH recovery for VFIO devices") Signed-off-by: Gavin Shan Reviewed-by: Russell Currey Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/eeh_driver.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) --- a/arch/powerpc/kernel/eeh_driver.c +++ b/arch/powerpc/kernel/eeh_driver.c @@ -166,6 +166,16 @@ static void *eeh_dev_save_state(void *da if (!edev) return NULL; + /* + * We cannot access the config space on some adapters. + * Otherwise, it will cause fenced PHB. We don't save + * the content in their config space and will restore + * from the initial config space saved when the EEH + * device is created. + */ + if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) + return NULL; + pdev = eeh_dev_to_pci_dev(edev); if (!pdev) return NULL; @@ -305,6 +315,19 @@ static void *eeh_dev_restore_state(void if (!edev) return NULL; + /* + * The content in the config space isn't saved because + * the blocked config space on some adapters. We have + * to restore the initial saved config space when the + * EEH device is created. + */ + if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) { + if (list_is_last(&edev->list, &edev->pe->edevs)) + eeh_pe_restore_bars(edev->pe); + + return NULL; + } + pdev = eeh_dev_to_pci_dev(edev); if (!pdev) return NULL;