CVE 2014-3968
The HVMOP_inject_msi function in Xen 4.2.x, 4.3.x, and 4.4.x allows local guest HVM administrators to cause a denial of service (host crash) via a large number of crafted requests, which trigger an error messages to be logged.
See the 
CVE page on Mitre.org
for more details.
