Basically he thinks any hypervisor that isn't OpenBSD is not secure.
"x86 virtualization is about basically placing another nearly full kernel, full of new bugs, on top of a nasty x86 architecture which barely has correct page protection. Then running your operating system on the other side of this brand new pile of shit." http://marc.info/?l=openbsd-misc&m=119318909016582
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From the link above comparing BSDs on Xen:
"OpenBSD probably works poorly by design, since its lead developer despises virtualisation."
I have seen this before. Can someone summarise the reasons why Theo de Raadt hates virtualisation?
Basically he thinks any hypervisor that isn't OpenBSD is not secure.
"x86 virtualization is about basically placing another nearly full kernel, full of new bugs, on top of a nasty x86 architecture which barely has correct page protection. Then running your operating system on the other side of this brand new pile of shit." http://marc.info/?l=openbsd-misc&m=119318909016582
(I see justinsaccount already posted this below.)
That's quite true, except that even OpenBSD is not _necessarily_ secure as a hypervisor.