From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756123AbcAXWSj (ORCPT ); Sun, 24 Jan 2016 17:18:39 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:60875 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755674AbcAXWE2 (ORCPT ); Sun, 24 Jan 2016 17:04:28 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Konrad Rzeszutek Wilk , Luis Henriques Subject: [PATCH 3.16.y-ckt 083/128] xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set. Date: Sun, 24 Jan 2016 22:00:38 +0000 Message-Id: <1453672883-2708-84-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1453672883-2708-1-git-send-email-luis.henriques@canonical.com> References: <1453672883-2708-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt23 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Konrad Rzeszutek Wilk commit 408fb0e5aa7fda0059db282ff58c3b2a4278baa0 upstream. commit f598282f51 ("PCI: Fix the NIU MSI-X problem in a better way") teaches us that dealing with MSI-X can be troublesome. Further checks in the MSI-X architecture shows that if the PCI_COMMAND_MEMORY bit is turned of in the PCI_COMMAND we may not be able to access the BAR (since they are memory regions). Since the MSI-X tables are located in there.. that can lead to us causing PCIe errors. Inhibit us performing any operation on the MSI-X unless the MEMORY bit is set. Note that Xen hypervisor with: "x86/MSI-X: access MSI-X table only after having enabled MSI-X" will return: xen_pciback: 0000:0a:00.1: error -6 enabling MSI-X for guest 3! When the generic MSI code tries to setup the PIRQ without MEMORY bit set. Which means with later versions of Xen (4.6) this patch is not neccessary. This is part of XSA-157 Reviewed-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Luis Henriques --- drivers/xen/xen-pciback/pciback_ops.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c index 4ee5fc080483..73dafdc494aa 100644 --- a/drivers/xen/xen-pciback/pciback_ops.c +++ b/drivers/xen/xen-pciback/pciback_ops.c @@ -212,6 +212,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev, struct xen_pcibk_dev_data *dev_data; int i, result; struct msix_entry *entries; + u16 cmd; if (unlikely(verbose_request)) printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n", @@ -223,7 +224,12 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev, if (dev->msix_enabled) return -EALREADY; - if (dev->msi_enabled) + /* + * PCI_COMMAND_MEMORY must be enabled, otherwise we may not be able + * to access the BARs where the MSI-X entries reside. + */ + pci_read_config_word(dev, PCI_COMMAND, &cmd); + if (dev->msi_enabled || !(cmd & PCI_COMMAND_MEMORY)) return -ENXIO; entries = kmalloc(op->value * sizeof(*entries), GFP_KERNEL);