As I probably should have known, Qubes developers are already well aware of this. See for example: https://blog.invisiblethings.org/papers/2015/x86_harmful.pdf
-- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/CACXcFmnXu8uW0p%2BrQFVcMAgr7qYdp-DKFATGPE3TOdzQkwtuVw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.