xen: suspend and resume system devices when running PVHVM

Otherwise we fail to properly suspend/resume all of the emulated devices.

Something between 2.6.38-rc2 and rc3 appears to have exposed this
issue, but it's always been wrong not to do this.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>

drivers/xen/manage.c

@@ -37,11 +37,19 @@ static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
 #ifdef CONFIG_PM_SLEEP
 static int xen_hvm_suspend(void *data)
 {
+	int err;
 	struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
 	int *cancelled = data;
 
 	BUG_ON(!irqs_disabled());
 
+	err = sysdev_suspend(PMSG_SUSPEND);
+	if (err) {
+		printk(KERN_ERR "xen_hvm_suspend: sysdev_suspend failed: %d\n",
+		       err);
+		return err;
+	}
+
 	*cancelled = HYPERVISOR_sched_op(SCHEDOP_shutdown, &r);
 
 	xen_hvm_post_suspend(*cancelled);
@@ -53,6 +61,8 @@ static int xen_hvm_suspend(void *data)
 		xen_timer_resume();
 	}
 
+	sysdev_resume();
+
 	return 0;
 }