diff --git a/hypervisor/arch/x86/guest/vm.c b/hypervisor/arch/x86/guest/vm.c
index 44b2bfc46..2833be663 100644
--- a/hypervisor/arch/x86/guest/vm.c
+++ b/hypervisor/arch/x86/guest/vm.c
@@ -387,7 +387,7 @@ int prepare_vm(uint16_t pcpu_id)
 #else
 
 /* Create vm/vcpu for vm0 */
-int prepare_vm0(void)
+static int prepare_vm0(void)
 {
 	int err;
 	uint16_t i;
diff --git a/hypervisor/arch/x86/io.c b/hypervisor/arch/x86/io.c
index fec92ba9c..75075dc13 100644
--- a/hypervisor/arch/x86/io.c
+++ b/hypervisor/arch/x86/io.c
@@ -45,7 +45,7 @@ emulate_pio_post(struct acrn_vcpu *vcpu, const struct io_request *io_req)
  * @remark This function must be called after the VHM request corresponding to
  * \p vcpu being transferred to the COMPLETE state.
  */
-void dm_emulate_pio_post(struct acrn_vcpu *vcpu)
+static void dm_emulate_pio_post(struct acrn_vcpu *vcpu)
 {
 	uint16_t cur = vcpu->vcpu_id;
 	union vhm_request_buffer *req_buf = NULL;
@@ -188,7 +188,7 @@ void emulate_io_post(struct acrn_vcpu *vcpu)
  * @retval -ENODEV No proper handler found.
  * @retval -EIO The request spans multiple devices and cannot be emulated.
  */
-int32_t
+static int32_t
 hv_emulate_pio(const struct acrn_vcpu *vcpu, struct io_request *io_req)
 {
 	int32_t status = -ENODEV;
diff --git a/hypervisor/arch/x86/irq.c b/hypervisor/arch/x86/irq.c
index 7ec2c1b3d..e2315594d 100644
--- a/hypervisor/arch/x86/irq.c
+++ b/hypervisor/arch/x86/irq.c
@@ -64,7 +64,7 @@ uint32_t alloc_irq_num(uint32_t req_irq)
  * @pre: irq is not in irq_static_mappings
  * free irq num allocated via alloc_irq_num()
  */
-void free_irq_num(uint32_t irq)
+static void free_irq_num(uint32_t irq)
 {
 	uint64_t rflags;
 
@@ -130,7 +130,7 @@ uint32_t alloc_irq_vector(uint32_t irq)
 }
 
 /* free the vector allocated via alloc_irq_vector() */
-void free_irq_vector(uint32_t irq)
+static void free_irq_vector(uint32_t irq)
 {
 	struct irq_desc *desc;
 	uint32_t vr;
diff --git a/hypervisor/arch/x86/virq.c b/hypervisor/arch/x86/virq.c
index ee344ad7d..1b5ede5b9 100644
--- a/hypervisor/arch/x86/virq.c
+++ b/hypervisor/arch/x86/virq.c
@@ -180,7 +180,7 @@ static int vcpu_do_pending_extint(const struct acrn_vcpu *vcpu)
  * 2. native LAPIC interrupt pending/EOI status
  * 3. CPU stuck or not
  */
-void dump_lapic(void)
+static void dump_lapic(void)
 {
 	dev_dbg(ACRN_DBG_INTR,
 		"LAPIC: TIME %08x, init=0x%x cur=0x%x ISR=0x%x IRR=0x%x",
diff --git a/hypervisor/debug/profiling.c b/hypervisor/debug/profiling.c
index 489de2f0d..bf1e50d26 100644
--- a/hypervisor/debug/profiling.c
+++ b/hypervisor/debug/profiling.c
@@ -710,7 +710,7 @@ reconfig:
 /*
  * Initialize sep state and enable PMU counters
  */
-void profiling_start_pmu(void)
+static void profiling_start_pmu(void)
 {
 	uint16_t i;
 
@@ -751,7 +751,7 @@ void profiling_start_pmu(void)
 /*
  * Reset sep state and Disable all the PMU counters
  */
-void profiling_stop_pmu(void)
+static void profiling_stop_pmu(void)
 {
 	uint16_t i;