The register_smm_enter_before_cb registers a callback of type
smm_switch_cb_t that will be called before the processor
enters System Management Mode.
The register_smm_enter_after_cb registers a callback of type
smm_switch_cb_t that will be called after the processor
has entered System Management Mode.
The register_smm_leave_before_cb registers a callback of type
smm_switch_cb_t that will be called before the processor
leaves System Management Mode.
The register_smm_leave_after_cb registers a callback of type
smm_switch_cb_t that will be called after the processor
has left System Management Mode.
The callback in all cases looks like this:
This callback type is used by the
smm_instrumentation_subscribe to implement instrumentation.
typedef void (*smm_switch_cb_t)(
conf_object_t *obj, conf_object_t *cpu,
lang_void *user_data);
The obj argument is the user object that registered the callback, or NULL if no such object exists.
The cpu argument is the processor that enters/leaves System Management Mode.
The user_data argument is the callback user data, passed to the register methods.