Feel free to send some patches to implement this! Alternatively, you could also try to write a mail to the virtio-rng maintainer (see the MAINTAINER file in the top directory of the sources), maybe he can help.
Feel free to send some patches to implement this! Alternatively, you could also try to write a mail to the virtio-rng maintainer (see the MAINTAINER file in the top directory of the sources), maybe he can help.