bhyve vmm ops could have stronger guardrail
When bhyve is initialized, it chooses a
vmm_ops set, based on the physical CPU (Intel or AMD) it's running on. The macros which call into this struct have explicit checks for it being non-NULL, which should never be possible given our guards anyways. To simplify those macros and maintain the safety, we could populate a null-ish
vmm_ops struct with functions that simply panic.