Create  a file named

/etc/polkit-1/localauthority/50-local.d/50-org.libvirt-group-access.pkla

and put the following lines in it

[libvirt group Management Access]
Identity=unix-group:libvirt
Action=org.libvirt.unix.manage
ResultAny=yes
ResultInactive=yes
ResultActive=yes

Create a group name libvirt (if it does not already exist)

groupadd libvirt

Put each user who needs access to the VMM Console in the group with the following command

usermod -a -G libvirt user_name