Add support for -display vnc

Signed-off-by: NJes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

qemu-options.hx

@@ -592,7 +592,8 @@ ETEXI
 
 DEF("display", HAS_ARG, QEMU_OPTION_display,
     "-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
-    "            [,window_close=on|off]|curses|none\n"
+    "            [,window_close=on|off]|curses|none|\n"
+    "            vnc=<display>[,<optargs>]\n"
     "                select display type\n", QEMU_ARCH_ALL)
 STEXI
 @item -display @var{type}
@@ -615,6 +616,8 @@ graphics card, but its output will not be displayed to the QEMU
 user. This option differs from the -nographic option in that it
 only affects what is done with video output; -nographic also changes
 the destination of the serial and parallel port data.
+@item vnc
+Start a VNC server on display <arg>
 @end table
 ETEXI
 

vl.c

@@ -1611,6 +1611,20 @@ static DisplayType select_display(const char *p)
         fprintf(stderr, "SDL support is disabled\n");
         exit(1);
 #endif
+    } else if (strstart(p, "vnc", &opts)) {
+        display_remote++;
+
+        if (*opts) {
+            const char *nextopt;
+
+            if (strstart(opts, "=", &nextopt)) {
+                vnc_display = nextopt;
+            }
+        }
+        if (!vnc_display) {
+            fprintf(stderr, "VNC requires a display argument vnc=<display>\n");
+            exit(1);
+        }
     } else if (strstart(p, "curses", &opts)) {
 #ifdef CONFIG_CURSES
         display = DT_CURSES;