It's the one distributed with the engine: /usr/share/virtio-win/virtio-win-1.9.16.iso "2. Virtio-win licence: This License Agreement ("License") applies to the VirtIO paravirtualized drivers for Windows(R) ("virtio-win") software ("Program") and any related updates or patches to the Program regardless of how you ("User") obtain such updates or patches. 1. Intellectual Property Rights. The Program is owned by Red Hat and others and is protected under copyright and other laws. Title to the Program or to any copy, modification, or merged portion shall remain with the aforementioned. The "Red Hat" trademark and the "Shadowman" logo are registered trademarks of Red Hat in the U.S. and other countries. 2. Program License Grant. Red Hat grants User a non-exclusive, non-transferable license to use the Program during the term of and on systems with fully-paid applicable Red Hat subscription(s) provided User may not: (a) modify, copy, or create any derivative works of the Program; (b) decompile, disassemble or reverse engineer the Program (except to the extent permitted by applicable law); (c) redistribute, encumber, sell, rent, lease, sublicense, or otherwise transfer rights to the Program (except to the extent permitted herein); or (d) remove or alter any trademark, logo, copyright or other proprietary notices, legends, symbols or labels in the Program. Upon expiration of the term set forth above, User will promptly remove, delete or destroy all copies of the Program in its possession."