Nothing.
EDI contains the VM handle of the CRTC owner. ESI contains the VM handle of the MemC owner.
This is an information service that is used by mini-VDDs to decide whether to virtualize or pass through I/O when virtualizing extended registers. See the S3 example mini-VDD routine mini-VDD VirtualCRTCOut for an example of how VDD_Get_VM_Info is used during virtualization.