diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index fedf629..6cbe074 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -105,8 +105,8 @@
 
 static const char *fb_mmio_name = "fb_range";
 static struct resource *fb_mmio;
-struct resource *hyperv_mmio;
-DEFINE_SEMAPHORE(hyperv_mmio_lock);
+static struct resource *hyperv_mmio;
+static DEFINE_SEMAPHORE(hyperv_mmio_lock);
 
 static int vmbus_exists(void)
 {