I'm unsure of the security of simultaneous multithreading on modern x86 CPUs
This is a red herring. Where are all the people that are unsure of the security of virtualization? There is some Xen vulnerability every year that is the equivalent of the house burning down, but where is the Azure support article that suggests disabling Xen? (Oh right, you can't.)I mean, the article is totally right of course, you shouldn't run untrusted code - THAT INCLUDES THE FREAKING HYPERVISOR.