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
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -298,12 +298,16 @@
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;