Para-virtualized frontend driver for Xen guest OS

modulename: drm_xen_front.ko

configname: CONFIG_DRM_XEN_FRONTEND

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>Para-virtualized frontend driver for Xen guest OS
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Choose this option if you want to enable a para-virtualized
frontend DRM/KMS driver for Xen guest OSes.

source code:
drivers/gpu/drm//xen/