Dynamic modes support for PV xenfb

diff -r 1f4b29eaf7f4 tools/ioemu/hw/xenfb.c
@@ -264,6 +264,9 @@ struct xenfb *xenfb_new(int domid, Displ
 	xenfb->ds = ds;
 	xenfb_device_set_domain(&xenfb->fb, domid);
 	xenfb_device_set_domain(&xenfb->kbd, domid);
+
+	/* Indicate we have the frame buffer resize feature */
+	xenfb_xs_printf(xenfb->xsh, xenfb->fb.nodename, "feature-resize", "1");
 
 	fprintf(stderr, "FB: Waiting for KBD backend creation\n");
 	xenfb_wait_for_backend(&xenfb->kbd, xenfb_backend_created_kbd);

@@ -510,6 +513,13 @@ static void xenfb_on_fb_event(struct xen
 			}
 			xenfb_guest_copy(xenfb, x, y, w, h);
 			break;
+		case XENFB_TYPE_RESIZE:
+			w = event->resize.width;
+			h = event->resize.height;
+			xenfb->width = w;
+			xenfb->height = h;
+			dpy_resize(xenfb->ds, xenfb->width, xenfb->height);
+			break;
 		}
 	}
 	mb();			/* ensure we're done with ring contents */

diff -r 1f4b29eaf7f4 xen/include/public/io/fbif.h
@@ -50,12 +50,26 @@ struct xenfb_update
     int32_t height; /* rect height */
 };
 
+/*
+ * Framebuffer resize notification event
+ * Capable backend sets feature-resize in xenstore.
+ */
+#define XENFB_TYPE_RESIZE 3
+
+struct xenfb_resize
+{
+    uint8_t type;    /* XENFB_TYPE_RESIZE */
+    int32_t width;   /* xres */
+    int32_t height;  /* yres */
+};
+
 #define XENFB_OUT_EVENT_SIZE 40
 
 union xenfb_out_event
 {
     uint8_t type;
     struct xenfb_update update;
+    struct xenfb_resize resize;
     char pad[XENFB_OUT_EVENT_SIZE];
 };
 

@@ -111,8 +125,12 @@ struct xenfb_page
      * PAGE_SIZE / sizeof(*pd) bytes.  With PAGE_SIZE == 4096 and
      * sizeof(unsigned long) == 4, that's 4 Megs.  Two directory
      * pages should be enough for a while.
+     *
+     * Increased to 3 to support 1280x1024 resolution on a 64bit system
+     *  (1280*1024*4)/PAGE_SIZE = 1280 pages required
+     *  PAGE_SIZE/64bit long = 512 pages per page directory
      */
-    unsigned long pd[2];
+    unsigned long pd[3];
 };
 
 /*