XEN PV Calls frontend driver

modulename: pvcalls-front.ko

configname: CONFIG_XEN_PVCALLS_FRONTEND

Linux Kernel Configuration
└─>Device Drivers
└─>Xen driver support
└─>XEN PV Calls frontend driver
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Experimental frontend for the Xen PV Calls protocol
(https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
sends a small set of POSIX calls to the backend, which
implements them.

source code:
drivers/xen/pvcalls-front.c