Xen: register panic notifier to take crashes of xen guests on panic

Register a panic notifier so that when the guest crashes it can shut
down the domain and indicate it was a crash to the host.

Signed-off-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

arch/x86/xen/enlighten.c

@@ -1040,6 +1040,26 @@ static void xen_crash_shutdown(struct pt_regs *regs)
 	xen_reboot(SHUTDOWN_crash);
 }
 
+static int
+xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	struct sched_shutdown r = { .reason = SHUTDOWN_crash};
+
+	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
+		BUG();
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block xen_panic_block = {
+	.notifier_call= xen_panic_event,
+};
+
+int xen_panic_handler_init(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
+	return 0;
+}
+
 static const struct machine_ops __initdata xen_machine_ops = {
 	.restart = xen_restart,
 	.halt = xen_machine_halt,

arch/x86/xen/setup.c

@@ -226,6 +226,8 @@ void __init xen_arch_setup(void)
 	struct physdev_set_iopl set_iopl;
 	int rc;
 
+	xen_panic_handler_init();
+
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
 

arch/x86/xen/xen-ops.h

@@ -101,4 +101,6 @@ void xen_sysret32(void);
 void xen_sysret64(void);
 void xen_adjust_exception_frame(void);
 
+extern int xen_panic_handler_init(void);
+
 #endif /* XEN_OPS_H */