diff options
Diffstat (limited to 'main/linux-grsec/xsa157-0005-xen-pciback-Don-t-allow-MSI-X-ops-if-PCI_COMMAND_MEM.patch')
| -rw-r--r-- | main/linux-grsec/xsa157-0005-xen-pciback-Don-t-allow-MSI-X-ops-if-PCI_COMMAND_MEM.patch | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/main/linux-grsec/xsa157-0005-xen-pciback-Don-t-allow-MSI-X-ops-if-PCI_COMMAND_MEM.patch b/main/linux-grsec/xsa157-0005-xen-pciback-Don-t-allow-MSI-X-ops-if-PCI_COMMAND_MEM.patch new file mode 100644 index 0000000000..85f06546c7 --- /dev/null +++ b/main/linux-grsec/xsa157-0005-xen-pciback-Don-t-allow-MSI-X-ops-if-PCI_COMMAND_MEM.patch @@ -0,0 +1,64 @@ +From e9ab9e04ed76ef06b4ba9a30b3724ca563fdf1fa Mon Sep 17 00:00:00 2001 +From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> +Date: Mon, 2 Nov 2015 18:13:27 -0500 +Subject: [PATCH v2 XSA157 5/5] xen/pciback: Don't allow MSI-X ops if + PCI_COMMAND_MEMORY is not set. + +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 + +CC: stable@vger.kernel.org +Reviewed-by: Jan Beulich <jbeulich@suse.com> +Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> +--- + 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 648c09c..edb9357 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); +-- +2.1.0 + |