- Implement the PM1_EVT and PM1_CTL registers required by ACPI.
The PM1_EVT register is mostly a dummy as bhyve doesn't support any
of the hardware-initiated events. The only bit of PM1_CNT that is
implemented are the sleep request bits (SPL_EN and SLP_TYP) which
request a graceful power off for S5. In particular, for S5, bhyve
exits with a non-zero value which terminates the loop in vmrun.sh.
- Emulate the Reset Control register at I/O port 0xcf9 and advertise
it as the reset register via ACPI.
- Advertise an _S5 package.
- Extend the in/out interface to allow an in/out handler to request
that the hypervisor trigger a reset or power-off.
- While here, note that all vCPUs in a guest support C1 ("hlt").
Reviewed by: neel (earlier version)