alt Hacker NewsI think it should classify as an escape or leak.
If one microVM can use the cpu in such a way that the registers can be used to communicate or exfiltrate/spy (the only difference being the directionality of the intent) by another microVM that is a leak on that microVM separation level.
Spy seems inappropriate if you can only read information stored in this side channel intentionally.
We'd first need to establish that this side channel leaks usable information during regular use.