[PATCH 4 of 6] xend: Don't crash due to weird PCI devices

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

# HG changeset patch
# User Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
# Date 1332610898 14400
# Node ID d42921da3931026ecf5da7c0e5bb86074e77cf71
# Parent  75798a472b1a9121adda166b6fd05ba8473a44f0
xend: Don't crash due to weird PCI devices

This fixes Red Hat BZ 767742 where a user had some truly
weird PCI devices:

$ lspci -vvv -xxx -s 0000:01:00.0
01:00.0 VGA compatible controller: nVidia Corporation GT218 [NVS 3100M] (rev
ff) (prog-if ff)
 !!! Unknown header type 7f
00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

And xend would report:

ERROR (pci:1272) Caught 'Looped capability chain: 0000:01:00.0'

This fixes it.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff -r 75798a472b1a -r d42921da3931 tools/python/xen/util/pci.py
--- a/tools/python/xen/util/pci.py	Sat Mar 24 13:41:38 2012 -0400
+++ b/tools/python/xen/util/pci.py	Sat Mar 24 13:41:38 2012 -0400
@@ -1268,7 +1268,12 @@ class PciDevice:
             pass
 
     def get_info_from_sysfs(self):
-        self.find_capability(0x11)
+        try:
+            self.find_capability(0x11)
+        except PciDeviceParseError, err:
+            log.error("Caught '%s'" % err)
+            return False
+
         sysfs_mnt = find_sysfs_mnt()
         if sysfs_mnt == None:
             return False