[PATCH 3 of 3] 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 1333398413 14400
# Node ID f789a3effeb6f876b9672e6e64bbd98857f59b61
# Parent  caefa03c38366c3e70d937bc95740c5d33c0892a
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.

Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff -r caefa03c3836 -r f789a3effeb6 tools/python/xen/util/pci.py
--- a/tools/python/xen/util/pci.py	Mon Apr 02 16:26:53 2012 -0400
+++ b/tools/python/xen/util/pci.py	Mon Apr 02 16:26:53 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