diff --git a/xen/arch/x86/hpet.c b/xen/arch/x86/hpet.c
index a2df1c7df4..79c07f6a9e 100644
--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -49,7 +49,7 @@ static struct hpet_event_channel *__read_mostly hpet_events;
 /* msi hpet channels used for broadcast */
 static unsigned int __read_mostly num_hpets_used;
 
-DEFINE_PER_CPU(struct hpet_event_channel *, cpu_bc_channel);
+static DEFINE_PER_CPU(struct hpet_event_channel *, cpu_bc_channel);
 
 unsigned long __initdata hpet_address;
 int8_t __initdata opt_hpet_legacy_replacement = -1;