diff -urN xen-2.0/xen/include/public/io/domain_controller.h xen-2.0-sysrq/xen/include/public/io/domain_controller.h
--- xen-2.0/xen/include/public/io/domain_controller.h	2004-11-17 22:51:47.000000000 +0000
+++ xen-2.0-sysrq/xen/include/public/io/domain_controller.h	2004-12-03 13:39:43.000000000 +0000
@@ -555,7 +555,8 @@
 #define CMSG_SHUTDOWN_REBOOT    1   /* Clean shutdown (SHUTDOWN_reboot).     */
 #define CMSG_SHUTDOWN_SUSPEND   2   /* Create suspend info, then             */
                                     /* SHUTDOWN_suspend.                     */
-
+#define CMSG_SHUTDOWN_SYSRQ_MIN 33  /* Lowest subtype that will be interpreted */
+#define CMSG_SHUTDOWN_SYSRQ_MAX 127 /* as an ASCII sysrq handler (and highest) */
 
 /******************************************************************************
  * MEMORY CONTROLS
diff -urN xen-2.0/linux-2.6.9-xen-sparse/arch/xen/kernel/reboot.c xen-2.0-sysrq/linux-2.6.9-xen-sparse/arch/xen/kernel/reboot.c
--- xen-2.0/linux-2.6.9-xen-sparse/arch/xen/kernel/reboot.c	2004-11-17 22:51:41.000000000 +0000
+++ xen-2.0-sysrq/linux-2.6.9-xen-sparse/arch/xen/kernel/reboot.c	2004-12-03 14:03:58.000000000 +0000
@@ -8,6 +8,7 @@
 #include <linux/unistd.h>
 #include <linux/module.h>
 #include <linux/reboot.h>
+#include <linux/sysrq.h>
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
 #include <asm-xen/ctrl_if.h>
@@ -226,6 +227,15 @@
         shutting_down = msg->subtype;
         schedule_work(&shutdown_work);
     }
+    else if (msg->subtype >= CMSG_SHUTDOWN_SYSRQ_MIN &&
+             msg->subtype <= CMSG_SHUTDOWN_SYSRQ_MAX)
+    {
+#ifdef CONFIG_MAGIC_SYSRQ
+        handle_sysrq(msg->subtype, NULL, NULL);
+#else
+        printk("sysrq not supported\n");
+#endif
+    }
     else
     {
         printk("Ignore spurious shutdown request\n");