xen/pci: Try harder to get PXM information for Xen

If the device being added to Xen is not contained in the ACPI table,
walk the PCI device tree to find a parent that is contained in the ACPI
table before finding the PXM information from this device.

Previously, it would try to get a handle for the device, then the
device's bridge, then the physfn.  This changes the order so that it
tries to get a handle for the device, then the physfn, the walks up the
PCI device tree.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index 95ee4302ffb8..7494dbeb4409 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -19,6 +19,7 @@
 
 #include <linux/pci.h>
 #include <linux/acpi.h>
+#include <linux/pci-acpi.h>
 #include <xen/xen.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/xen.h>
@@ -67,12 +68,22 @@ static int xen_add_device(struct device *dev)
 
 #ifdef CONFIG_ACPI
                 handle = ACPI_HANDLE(&pci_dev->dev);
-                if (!handle && pci_dev->bus->bridge)
-                        handle = ACPI_HANDLE(pci_dev->bus->bridge);
 #ifdef CONFIG_PCI_IOV
                 if (!handle && pci_dev->is_virtfn)
                         handle = ACPI_HANDLE(physfn->bus->bridge);
 #endif
+                if (!handle) {
+                        /*
+                         * This device was not listed in the ACPI name space at
+                         * all. Try to get acpi handle of parent pci bus.
+                         */
+                        struct pci_bus *pbus;
+                        for (pbus = pci_dev->bus; pbus; pbus = pbus->parent) {
+                                handle = acpi_pci_get_bridge_handle(pbus);
+                                if (handle)
+                                        break;
+                        }
+                }
                 if (handle) {
                         acpi_status status;