From patchwork Mon May 19 03:01:10 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 4198981 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 7BE1D9F32B for ; Mon, 19 May 2014 03:01:33 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B4DFF20274 for ; Mon, 19 May 2014 03:01:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2B0120279 for ; Mon, 19 May 2014 03:01:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752336AbaESDBZ (ORCPT ); Sun, 18 May 2014 23:01:25 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:36513 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752444AbaESDBU (ORCPT ); Sun, 18 May 2014 23:01:20 -0400 Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 19 May 2014 13:01:16 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 2B3E82CE8040; Mon, 19 May 2014 13:01:16 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s4J2dqPr55377932; Mon, 19 May 2014 12:39:52 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s4J31Fih013423; Mon, 19 May 2014 13:01:15 +1000 Received: from ozlabs.au.ibm.com (ozlabs.au.ibm.com [9.190.163.12]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s4J31FVa013417; Mon, 19 May 2014 13:01:15 +1000 Received: from shangw (haven.au.ibm.com [9.190.164.82]) by ozlabs.au.ibm.com (Postfix) with ESMTP id E6072A011B; Mon, 19 May 2014 13:01:14 +1000 (EST) Received: by shangw (Postfix, from userid 1000) id 6CF6A3E0291; Mon, 19 May 2014 13:01:15 +1000 (EST) From: Gavin Shan To: kvm@vger.kernel.org Cc: alex.williamson@redhat.com, bhelgaas@google.com, linux-pci@vger.kernel.org, Gavin Shan Subject: [PATCH 4/4] vfio/pci: Restore MSIx message prior to enabling Date: Mon, 19 May 2014 13:01:10 +1000 Message-Id: <1400468470-11262-5-git-send-email-gwshan@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1400468470-11262-1-git-send-email-gwshan@linux.vnet.ibm.com> References: <1400468470-11262-1-git-send-email-gwshan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14051903-7014-0000-0000-000004E8F5EF Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The MSIx vector table lives in device memory, which may be cleared as part of a backdoor device reset. This is the case on the IBM IPR HBA when the BIST is run on the device. When assigned to a QEMU guest, the guest driver does a pci_save_state(), issues a BIST, then does a pci_restore_state(). The BIST clears the MSIx vector table, but due to the way interrupts are configured the pci_restore_state() does not restore the vector table as expected. Eventually this results in an EEH error on Power platforms when the device attempts to signal an interrupt with the zero'd table entry. Fix the problem by restoring the host cached MSI message prior to enabling each vector. Reported-by: Wen Xiong Signed-off-by: Gavin Shan Signed-off-by: Alex Williamson --- drivers/vfio/pci/vfio_pci_intrs.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 9dd49c9..553212f 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -548,6 +549,20 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, return PTR_ERR(trigger); } + /* + * The MSIx vector table resides in device memory which may be cleared + * via backdoor resets. We don't allow direct access to the vector + * table so even if a userspace driver attempts to save/restore around + * such a reset it would be unsuccessful. To avoid this, restore the + * cached value of the message prior to enabling. + */ + if (msix) { + struct msi_msg msg; + + get_cached_msi_msg(irq, &msg); + write_msi_msg(irq, &msg); + } + ret = request_irq(irq, vfio_msihandler, 0, vdev->ctx[vector].name, trigger); if (ret) {