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 <zhangjukuo@huawei.com>
Tested-by: Zhang Jukuo <zhangjukuo@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index c489ef2..34fc418 100644 (file)
--- 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;

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index fd60806..c3e7dfc 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -694,11 +694,16 @@ static void __iomem *msix_map_region(struct pci_dev *dev, unsigned nr_entries)
 {
        resource_size_t phys_addr;
        u32 table_offset;
+       unsigned long flags;
        u8 bir;
 
        pci_read_config_dword(dev, dev->msix_cap + 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 NULL;
+
        table_offset &= PCI_MSIX_TABLE_OFFSET;
        phys_addr = pci_resource_start(dev, bir) + table_offset;