vfkit has a --timesync <vsock_num> option which uses vsock to send the current time on the host to the qemu-guest-agent service running inside the guest. This is particularly useful for keeping the guest clock synchronized after VM suspend/resume. This would be a helpful option to have in krunkit as well and would also maintain parity between the two.
This can now be implemented as host to guest vsock communication (connect mode) has now been merged: #87