CONFIG_EPAPR_PARAVIRT is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

ePAPR para-virtualization support

modulename: epapr_paravirt.ko

configname: CONFIG_EPAPR_PARAVIRT

Linux Kernel Configuration
└─>Platform support
└─>ePAPR para-virtualization support
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Enables ePAPR para-virtualization support for guests.

In case of doubt, say Y

source code:
arch/powerpc/kernel/