- f"csum=off,gso=off,guest_tso4=off,guest_tso6=off,guest_ecn=off,"
- f"mrg_rxbuf={mbuf if jumbo_frames else u'off'},{queue_size}"
+ f"csum={u'on' if csum else u'off'},gso={u'on' if gso else u'off'},"
+ f"guest_tso4=off,guest_tso6=off,guest_ecn=off,"
+ f"mrg_rxbuf={u'on,host_mtu=9200' if jumbo_frames else u'off'},"
+ f"{queue_size}"