fix-vga-scanning-code-overflow

xen虚拟机源代码安装包

Index: ioemu/hw/vga.c
===================================================================
--- ioemu.orig/hw/vga.c	2007-05-03 19:15:57.000000000 +0100
+++ ioemu/hw/vga.c	2007-05-03 19:46:13.000000000 +0100
@@ -1477,14 +1477,15 @@
  */
 static void vga_draw_graphic(VGAState *s, int full_update)
 {
-    int y1, y, update, page_min, page_max, linesize, y_start, double_scan, mask;
+    int y1, y, update, linesize, y_start, double_scan, mask;
     int width, height, shift_control, line_offset, bwidth;
     ram_addr_t page0, page1;
     int disp_width, multi_scan, multi_run;
     uint8_t *d;
     uint32_t v, addr1, addr;
     vga_draw_line_func *vga_draw_line;
-    
+    ram_addr_t page_min, page_max;
+
     full_update |= update_basic_params(s);
 
     s->get_resolution(s, &width, &height);
@@ -1575,8 +1576,8 @@
     addr1 = (s->start_addr * 4);
     bwidth = width * 4;
     y_start = -1;
-    page_min = 0x7fffffff;
-    page_max = -1;
+    page_min = 0;
+    page_max = 0;
     d = s->ds->data;
     linesize = s->ds->linesize;
     y1 = 0;
@@ -1606,9 +1607,9 @@
         if (update) {
             if (y_start < 0)
                 y_start = y;
-            if (page0 < page_min)
+            if (page_min == 0 || page0 < page_min)
                 page_min = page0;
-            if (page1 > page_max)
+            if (page_max == 0 || page1 > page_max)
                 page_max = page1;
             vga_draw_line(s, d, s->vram_ptr + addr, width);
             if (s->cursor_draw_line)