bhyve on AMD should report SVM as disabled
Upstreaming OS-8008 from SmartOS:
As reported in https://github.com/joyent/smartos-live/issues/843 a Windows guest will hang at boot on AMD boxes without the "-w" command line flag (Ignore accesses to unimplemented Model Specific Registers).
Looking at this it seems Windows tries to read
VM_CR MSR (
rdmsr to register 0xc0010114 on vcpu 3
It seems that Windows ignores the cpuid bits here and attempts to poke the MSR anyways.
To test this change I ran a DEBUG platform with the change on our AMD Epyc lab box and confirmed I was able to boot a Windows bhyve instance without the "-w" flag. I also got confirmation that the user who reported the original issue was able to do the same on their hardware with the provided patched platform.