OpenVPN bridge in KVM

i run openvpn inside kvm vm's no problems and no major packet loss to report (at least not due to openvpn)

remember that default openvpn goes over UDP so if the network between your 2 machines is bad then you will get packet loss, for more unreliable networks you might consider switching to TCP mode which handles retransmission and packet loss more gracefully leading to a more reliable VPN tunnel overall at the sacrifice of a small amount of performance.