How to create bridge in host

In host
1. service NetworkManager stop
2.virsh # iface-bridge em1 br0 --no-stp
3. service network restart
In guest
chose the "br0"

How to remove switch bridge

rm -f /etc/sysconfig/network-scripts/ifcfg-br0
vim /etc/sysconfig/network-scripts/ifcfg-eno1 as follows:
DEVICE="eno1"
ONBOOT=yes
NETBOOT=yes
UUID="a4be212f-4b57-4b04-8a1a-dfd16fd78d35"
DHCPV6C=yes
BOOTPROTO=dhcp
HWADDR="78:2b:cb:9a:73:9b"
TYPE=Ethernet
NAME="Boot Disk"
#NAME="eno1"
#BRIDGE=switch