xen: maintain clock offset over save/restore

Hook into the device model to make sure that timekeeping's resume handler
is called.  This deals with our clocksource's non-monotonicity over the
save/restore.  Explicitly call clock_has_changed() to make sure that
all the timers get retriggered properly.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index ba85fa2..675c3dd 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -34,14 +34,21 @@
 static int xen_suspend(void *data)
 {
 	int *cancelled = data;
+	int err;
 
 	BUG_ON(!irqs_disabled());
 
 	load_cr3(swapper_pg_dir);
 
+	err = device_power_down(PMSG_SUSPEND);
+	if (err) {
+		printk(KERN_ERR "xen_suspend: device_power_down failed: %d\n",
+		       err);
+		return err;
+	}
+
 	xen_mm_pin_all();
 	gnttab_suspend();
-	xen_time_suspend();
 	xen_pre_suspend();
 
 	/*
@@ -52,10 +59,11 @@
 	*cancelled = HYPERVISOR_suspend(virt_to_mfn(xen_start_info));
 
 	xen_post_suspend(*cancelled);
-	xen_time_resume();
 	gnttab_resume();
 	xen_mm_unpin_all();
 
+	device_power_up();
+
 	if (!*cancelled) {
 		xen_irq_resume();
 		xen_console_resume();
@@ -105,7 +113,8 @@
 
 	device_resume();
 
-
+	/* Make sure timer events get retriggered on all CPUs */
+	clock_was_set();
 out:
 #ifdef CONFIG_PREEMPT
 	thaw_processes();