From 6a878e5085fe97bd1e222b7883a1b815fcbbe4ed Mon Sep 17 00:00:00 2001 From: Yijing Wang Date: Wed, 28 Jan 2015 09:52:17 +0800 Subject: PCI: Fail MSI-X mappings if there's no space assigned to MSI-X BAR Unlike MSI, which is configured via registers in the MSI capability in Configuration Space, MSI-X is configured via tables in Memory Space. These MSI-X tables are mapped by a device BAR, and if no Memory Space has been assigned to the BAR, MSI-X cannot be used. Fail MSI-X setup if no space has been assigned for the BAR. Previously, we ioremapped the MSI-X table even if the resource hadn't been assigned. In this case, the resource address is undefined (and is often zero), which may lead to warnings or oopses in this path: pci_enable_msix msix_capability_init msix_map_region ioremap_nocache The PCI core sets resource flags to zero when it can't assign space for the resource (see reset_resource()). There are also some cases where it sets the IORESOURCE_UNSET flag, e.g., pci_reassigndev_resource_alignment(), pci_assign_resource(), etc. So we must check for both cases. [bhelgaas: changelog] Reported-by: Zhang Jukuo Tested-by: Zhang Jukuo Signed-off-by: Yijing Wang Signed-off-by: Bjorn Helgaas --- arch/x86/pci/xen.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/pci/xen.c') diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c index c489ef2c1a39..34fc4189ebf0 100644 --- a/arch/x86/pci/xen.c +++ b/arch/x86/pci/xen.c @@ -298,12 +298,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) map_irq.entry_nr = nvec; } else if (type == PCI_CAP_ID_MSIX) { int pos; + unsigned long flags; u32 table_offset, bir; pos = dev->msix_cap; pci_read_config_dword(dev, pos + PCI_MSIX_TABLE, &table_offset); bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR); + flags = pci_resource_flags(dev, bir); + if (!flags || (flags & IORESOURCE_UNSET)) + return -EINVAL; map_irq.table_base = pci_resource_start(dev, bir); map_irq.entry_nr = msidesc->msi_attrib.entry_nr; -- cgit