CVE-2015-8338

Xen 4.6.x and earlier does not properly enforce limits on page order inputs
for the (1) XENMEM_increase_reservation, (2) XENMEM_populate_physmap, (3)
XENMEM_exchange, and possibly other HYPERVISOR_memory_op suboperations,
which allows ARM guest OS administrators to cause a denial of service (CPU
consumption, guest reboot, or watchdog timeout and host reboot) and
possibly have unspecified other impact via unknown vectors.