INT 2F - MS WINDOWS - SWITCH VMs AND CALLBACK
AX = 1685h
BX = VM ID of virtual machine to switch to
CX = flags
bit 0 wait until interrupts enabled
bit 1 wait until critical section unowned
bits 2-15 reserved (zero)
DX:SI = priority boost (see VMM.INC)
ES:DI -> FAR procedure to callback
Return: CF set on error
AX = error code
01h invalid VM ID
02h invalid priority boost
03h invalid flags
CF clear if successful
event will be or has been called
Notes:  some DOS devices, such as networks, need to call functions in a
specific VM. This call forces the appropriate VM to be installed.
the callback procedure must preserve all registers and return with IRET
SeeAlso: INT 15/AX=1117h

See also: 2F1683

2F1685 - MS WINDOWS - SWITCH VMs AND CALLBACK