[libvirt] getFreeMemory reporting incorrectly?

Hi, I'm currently running 2 CentOS 5.3 systems, one running Xen 3.3 and libvirt 0.6.4 (called node1) and the other running Xen 3.0.3 (stock CentOS) and libvirt 0.6.4 (called node2). The machines are practically identical except for the upgraded Xen installation. When using the libvirt-python module, I'm getting strange values from getFreeMemory() on the Xen 3.3 machine. See below: Xen 3.0.3: [root@node2 ~]# python Python 2.4.3 (#1, Jan 21 2009, 01:10:13) [GCC 4.1.2 20071124 (Red Hat 4.1.2-42)] on linux2 Type "help", "copyright", "credits" or "license" for more information. 268959744 Which is correct since there's approximately 256MB free. Now in the Xen 3.3 box: Xen 3.3: [root@node1 ~]# python Python 2.4.3 (#1, Jan 21 2009, 01:10:13) [GCC 4.1.2 20071124 (Red Hat 4.1.2-42)] on linux2 Type "help", "copyright", "credits" or "license" for more information. 576460752303423488 node1 should actually be reporting 0MB free, but instead I'm getting this huge number. It would be nice if I had this much memory though... Anybody else run into this? Hany