x86: Bail from hpet_disable_legacy_broadcast() if legacy_hpet_event is uninitialised.

Signed-off-by: Keir Fraser <keir@xen.org>

diff --git a/xen/arch/x86/hpet.c b/xen/arch/x86/hpet.c
index 6fc7a35586abdd9630098ad5708a2a92a47c31e4..1107fb727f14114b20d47a399ee52e7ffa9ceb32 100644 (file)
--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -647,6 +647,9 @@ void hpet_disable_legacy_broadcast(void)
     u32 cfg;
     unsigned long flags;
 
+    if ( !legacy_hpet_event.shift )
+        return;
+
     spin_lock_irqsave(&legacy_hpet_event.lock, flags);
 
     legacy_hpet_event.flags |= HPET_EVT_DISABLE;