[Rdo-list] GRE traffic in openstack

Hey there, I have to set a GRE tunnel between VM1 deployed on top of Openstack and a physical server. I was wondering in this case How can I proceed. Can I do it the classic way by providing my VM1 with a floating ip and just set the tunnel as normal? by the way my ovs uses vxlan and not gre tunnel? Do you have any idea? In advance, thanks for your response. Sara