CONFIG_VIRTIO (not configurable)

modulename: virtio.ko

configname: CONFIG_VIRTIO

Linux Kernel Configuration
└─>Device Drivers
└─>VIRTIO
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
source code:
drivers/virtio/virtio.c
is selected by
CONFIG_VIRTIO_BALLOON