By the way, thanks to the clever Qubes design, quite few Xen exploits affect Qubes OS [0]. Especially after 4.0 with VT-d hardware virtualization [1].
[0] https://www.qubes-os.org/security/xsa/
[1] https://www.qubes-os.org/news/2017/07/31/qubes-40-rc1/#fully...