Xen for CentOS7

 Enable Repo : 

#yum install centos-release-xen

#yum update

#yum install xen

verify kernel

#uname -r

#xl info

Setup Bridging :

ip route show | grep 'default' | awk '{print $5}'

nmcli con add type bridge con-name xenbr0 ifname xenbr0
nmcli con modify xenbr0 bridge.stp no
nmcli con modify xenbr0 bridge.hello-time 0

nmcli con show
nmcli con modify "System eth0" connection.master xenbr0 connection.slave-type bridge
systemctl restart network