monitor: an interface of acrn-dm

A monitor component will be added to acrn-dm, which crteats socket,
bind and listening at /run/acrn/vmname. Acrnctl & acrnd could conn
-ect to the socket for communication, using defined message, in
include/monitor_msg.h
For each defined message, a message handler callback could be
registered via monitor_add_msg_handler(). On received of a defined
message, a certain call back will be called. Each callback can only
see the message sender's socket-fd.
When acrn-dm want report something, not triggered by incoming message
it can send broadcast message, use monitor_broadcast().

Acked-by: Eddie Dong <eddie.dong@intel.com>
Reviewed-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Yin, Fengwei <fengwei.yin@intel.com>
Signed-off-by: Tao, Yuhong <yuhong.tao@intel.com>

core/main.c

@@ -63,6 +63,7 @@
 #include "rtc.h"
 #include "version.h"
 #include "sw_load.h"
+#include "monitor.h"
 
 #define GUEST_NIO_PORT		0x488	/* guest upcalls via i/o port */
 
@@ -801,6 +802,7 @@ main(int argc, char *argv[])
 
 		vrtc_init(ctx, rtc_localtime);
 		sci_init(ctx);
+		monitor_init(ctx);
 
 		/*
 		 * Exit if a device emulation finds an error in its
@@ -863,6 +865,7 @@ main(int argc, char *argv[])
 		 */
 		mevent_dispatch();
 
+		monitor_close();
 		vm_pause(ctx);
 		fbsdrun_deletecpu(ctx, BSP);
 		vm_unsetup_memory(ctx);