参考：
https://forums.freebsd.org/threads/qemu-kvm-freebsd-guest-running-x-and-a-working-mouse.82460/
解决办法：
1、Add input device "EvTouch USB Graphics Tablet" in virt-manager.
具体配置如下：
<input type='tablet' bus='usb'>
<address type='usb' bus='0' port='1'/>
</input>2、安装utouch-kmod和xf86-input-evdev
pkg install utouch-kmod xf86-input-evdev
按照提示，做对应配置即可。
3、重启验证
附桌面安装方式（xfce+lightdm）：
https://book.bsdcn.org/di-4-zhang-zhuo-mian-an-zhuang/di-4.5-jie-an-zhuang-xfce.html
https://book.bsdcn.org/di-4-zhang-zhuo-mian-an-zhuang/di-4.8-jie-root-deng-lu-zhuo-mian.html
