mov ax, 4006h ; Restore Video Register State int 2fh
Restore Video Register State notifies a VM application that the virtual-display device (VDD) has relinquished its access to the video registers. The VM application should restore the video registers to any state necessary to continue uninterrupted foreground operation.
This function has no parameters.
The VDD calls this function only if the VM application has called Enable VM-Assisted Save/Restore (Interrupt 2Fh Function 4000h). Before calling this function, the VDD restores any registers it modified to the values they had when the VM application originally called Enable VM-Assisted Save/Restore. In other words, every register is guaranteed to be either unchanged or reset to a previous state; precisely which registers may be reset is undefined, but the set is restricted to those Sequencer and Graphics Controller registers that do not affect the display.
See also Interrupt 2Fh Function 4000h Enable VM-Assisted Save/Restore