diff -ru xen-3.0.1-orig/xen/common/page_alloc.c xen-3.0.1/xen/common/page_alloc.c
--- xen-3.0.1-orig/xen/common/page_alloc.c	2006-04-03 01:53:24.000000000 +0200
+++ xen-3.0.1/xen/common/page_alloc.c	2006-04-04 09:01:53.000000000 +0200
@@ -155,7 +155,7 @@
 
 void init_boot_pages(physaddr_t ps, physaddr_t pe)
 {
-    unsigned long bad_pfn;
+    unsigned long bad_pfn, bad_mask, i;
     char *p;
 
     ps = round_pgup(ps);
@@ -170,16 +170,36 @@
     while ( *p != '\0' )
     {
         bad_pfn = simple_strtoul(p, &p, 0);
+        bad_mask = ~0; /* mask specific to one page */
+
+        if ( *p == '/' )
+        {
+            p++;
+            bad_mask = simple_strtoul(p, &p, 0);
+            bad_pfn &= bad_mask; /* ignore address bits not covered by the mask */
+        }
 
         if ( *p == ',' )
             p++;
         else if ( *p != '\0' )
             break;
 
-        if ( (bad_pfn < max_page) && !allocated_in_map(bad_pfn) )
-        {
+        if ( bad_mask == ~0 )
             printk("Marking page %lx as bad\n", bad_pfn);
-            map_alloc(bad_pfn, 1);
+        else
+            printk("Marking pages %lx/%lx as bad\n",
+                   bad_pfn, bad_mask);
+
+        /* iterate over pages covered by the mask */
+        for ( i=0; (bad_pfn|i) < max_page ; i++ )
+        {
+            if ( !(i & bad_mask) )
+            {
+                if ( !allocated_in_map(bad_pfn|i) )
+                    map_alloc(bad_pfn|i, 1);
+                else
+                    printk("Warning, bad page %lx in use\n", bad_pfn|i);
+            }
         }
     }
 }