--- xen-4.5.1/tools/qemu-xen-traditional/hw/ne2000.c.orig	2015-06-09 16:32:24.000000000 +0100
+++ xen-4.5.1/tools/qemu-xen-traditional/hw/ne2000.c	2015-09-26 17:27:49.494334726 +0100
@@ -304,6 +304,9 @@
     }
 
     index = s->curpag << 8;
+    if (index >= NE2000_PMEM_END) {
+        index = s->start;
+    }
     /* 4 bytes for header */
     total_len = size + 4;
     /* address for next packet (4 bytes for CRC) */
@@ -387,15 +390,21 @@
         offset = addr | (page << 4);
         switch(offset) {
         case EN0_STARTPG:
-            s->start = val << 8;
+            if (val << 8 <= NE2000_PMEM_END) {
+                s->start = val << 8;
+            }
             s->tainted = 1;
             break;
         case EN0_STOPPG:
-            s->stop = val << 8;
+            if (val << 8 <= NE2000_PMEM_END) {
+                s->stop = val << 8;
+            }
             s->tainted = 1;
             break;
         case EN0_BOUNDARY:
-            s->boundary = val;
+            if (val << 8 < NE2000_PMEM_END) {
+                s->boundary = val;
+            }
             break;
         case EN0_IMR:
             s->imr = val;
@@ -436,7 +445,9 @@
             s->phys[offset - EN1_PHYS] = val;
             break;
         case EN1_CURPAG:
-            s->curpag = val;
+            if (val << 8 < NE2000_PMEM_END) {
+                s->curpag = val;
+            }
             s->tainted = 1;
             break;
         case EN1_MULT ... EN1_MULT + 7: