CONFIG_XEN_PVHVM (not configurable)

modulename: enlighten_hvm.ko

and/or

platform-pci.ko

configname: CONFIG_XEN_PVHVM

Linux Kernel Configuration
└─>XEN_PVHVM
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
source code:
drivers/xen/platform-pci.c