Configure Network bridge and KVM in ubuntu

Step:1 Verify Whether your system support hardware virtualization

egrep -c '(vmx|svm)' /proc/cpuinfo

1

If the output is greater than 0 then it means your system supports Virtualization 

else reboot your system, then go to BIOS settings and enable VT technology.

Now Install “kvm-ok” utility using below command, it is used to determine 

if your server is capable of running hardware accelerated KVM virtual machines

sudo apt install cpu-checker

sudo kvm-ok

INFO: /dev/kvm exists

KVM acceleration can be used

Step:2 Install KVM and its required packages

sudo apt update

apt install qemu qemu-kvm libvirt-bin  bridge-utils  virt-manager

Step:3 Start & enable libvirtd service

service libvirtd start

update-rc.d libvirtd enable

service libvirtd status

Step:4 Configure Network Bridge for KVM virtual Machines

vi /etc/netplan/50-cloud-init.yaml

network:

  version: 2

  ethernets:

    ens33:

      dhcp4: no

      dhcp6: no

  bridges:

    br0:

      interfaces: [ens33]

      dhcp4: no

      addresses: [192.168.1.201/24]

      gateway4: 192.168.1.1

      nameservers:

        addresses: [8.8.8.8]

sudo netplan apply

sudo networkctl status -a

ifconfig

Step:5 Configure VM's in KVM

virt-manager

Ref: 

https://www.linuxtechi.com/install-configure-kvm-ubuntu-18-04-server/