diff --git a/hypervisor/arch/x86/cpu_primary.S b/hypervisor/arch/x86/cpu_primary.S
index be389b286..76066966e 100644
--- a/hypervisor/arch/x86/cpu_primary.S
+++ b/hypervisor/arch/x86/cpu_primary.S
@@ -127,7 +127,8 @@ primary_start_long_mode:
 
     /* Initialize temporary stack pointer */
     lea     _ld_bss_end(%rip), %rsp
-    add     $CPU_PAGE_SIZE,%rsp
+    /*0x1000 = CPU_PAGE_SIZE*/
+    add     $0x1000,%rsp
     /* 16 = CPU_STACK_ALIGN */
     and     $(~(16 - 1)),%rsp
 
@@ -213,20 +214,24 @@ cpu_primary32_gdt_ptr:
     .quad   cpu_primary32_gdt
 
 /* PML4, PDPT, and PD tables initialized to map first 4 GBytes of memory */
-    .align  CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    .align  0x1000
     .global cpu_boot32_page_tables_start
 cpu_boot32_page_tables_start:
     /* 0x3 = (IA32E_COMM_P_BIT | IA32E_COMM_RW_BIT) */
     .quad   cpu_primary32_pdpt_addr + 0x3
-    .align  CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    .align  0x1000
 cpu_primary32_pdpt_addr:
     address = 0
     .rept   4
     /* 0x3 = (IA32E_COMM_P_BIT | IA32E_COMM_RW_BIT) */
     .quad   cpu_primary32_pdt_addr + address + 0x3
-    address = address + CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    address = address + 0x1000
     .endr
-    .align  CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    .align  0x1000
 cpu_primary32_pdt_addr:
     address = 0
     .rept  2048
diff --git a/hypervisor/arch/x86/guest/vcpu.c b/hypervisor/arch/x86/guest/vcpu.c
index e21df0f92..a1652986e 100644
--- a/hypervisor/arch/x86/guest/vcpu.c
+++ b/hypervisor/arch/x86/guest/vcpu.c
@@ -63,7 +63,7 @@ int create_vcpu(uint16_t pcpu_id, struct vm *vm, struct vcpu **rtn_vcpu_handle)
 	 * vcpu->vcpu_id = vm->hw.created_vcpus;
 	 * vm->hw.created_vcpus++;
 	 */
-	vcpu->vcpu_id = atomic_xadd(&vm->hw.created_vcpus, 1);
+	vcpu->vcpu_id = atomic_xadd16(&vm->hw.created_vcpus, 1U);
 	/* vm->hw.vcpu_array[vcpu->vcpu_id] = vcpu; */
 	atomic_store64(
 		(long *)&vm->hw.vcpu_array[vcpu->vcpu_id],
@@ -246,7 +246,7 @@ void destroy_vcpu(struct vcpu *vcpu)
 		(long *)&vcpu->vm->hw.vcpu_array[vcpu->vcpu_id],
 		(long)NULL);
 
-	atomic_dec(&vcpu->vm->hw.created_vcpus);
+	atomic_dec16(&vcpu->vm->hw.created_vcpus);
 
 	vlapic_free(vcpu);
 	free(vcpu->arch_vcpu.vmcs);
diff --git a/hypervisor/arch/x86/guest/vm.c b/hypervisor/arch/x86/guest/vm.c
index e96a90b32..4becbeb40 100644
--- a/hypervisor/arch/x86/guest/vm.c
+++ b/hypervisor/arch/x86/guest/vm.c
@@ -104,7 +104,7 @@ int create_vm(struct vm_description *vm_desc, struct vm **rtn_vm)
 	vm->attr.id = id;
 	vm->attr.boot_idx = id;
 
-	atomic_store(&vm->hw.created_vcpus, 0);
+	atomic_store16(&vm->hw.created_vcpus, 0U);
 
 	/* gpa_lowtop are used for system start up */
 	vm->hw.gpa_lowtop = 0UL;
diff --git a/hypervisor/arch/x86/mmu.c b/hypervisor/arch/x86/mmu.c
index 5c6112728..fb0d8809a 100644
--- a/hypervisor/arch/x86/mmu.c
+++ b/hypervisor/arch/x86/mmu.c
@@ -52,7 +52,7 @@ static struct vmx_capability {
  * is the value of the VPID VM-execution control field in the VMCS.
  * (VM entry ensures that this value is never 0000H).
  */
-static int vmx_vpid_nr = VMX_MIN_NR_VPID;
+static uint16_t vmx_vpid_nr = VMX_MIN_NR_VPID;
 
 #define INVEPT_TYPE_SINGLE_CONTEXT      1UL
 #define INVEPT_TYPE_ALL_CONTEXTS        2UL
@@ -71,7 +71,7 @@ struct invept_desc {
 	uint64_t _res;
 };
 
-static inline void _invvpid(uint64_t type, int vpid, uint64_t gva)
+static inline void _invvpid(uint64_t type, uint16_t vpid, uint64_t gva)
 {
 	int error = 0;
 
@@ -142,28 +142,28 @@ int check_vmx_mmu_cap(void)
 	return 0;
 }
 
-int allocate_vpid(void)
+uint16_t allocate_vpid(void)
 {
-	int vpid = atomic_xadd(&vmx_vpid_nr, 1);
+	uint16_t vpid = atomic_xadd16(&vmx_vpid_nr, 1U);
 
 	/* TODO: vpid overflow */
 	if (vpid >= VMX_MAX_NR_VPID) {
 		pr_err("%s, vpid overflow\n", __func__);
 		/*
 		 * set vmx_vpid_nr to VMX_MAX_NR_VPID to disable vpid
-		 * since next atomic_xadd will always large than
+		 * since next atomic_xadd16 will always large than
 		 * VMX_MAX_NR_VPID.
 		 */
 		vmx_vpid_nr = VMX_MAX_NR_VPID;
-		vpid = 0;
+		vpid = 0U;
 	}
 
 	return vpid;
 }
 
-void flush_vpid_single(int vpid)
+void flush_vpid_single(uint16_t vpid)
 {
-	if (vpid == 0)
+	if (vpid == 0U)
 		return;
 
 	_invvpid(VMX_VPID_TYPE_SINGLE_CONTEXT, vpid, 0UL);
@@ -171,7 +171,7 @@ void flush_vpid_single(int vpid)
 
 void flush_vpid_global(void)
 {
-	_invvpid(VMX_VPID_TYPE_ALL_CONTEXT, 0, 0UL);
+	_invvpid(VMX_VPID_TYPE_ALL_CONTEXT, 0U, 0UL);
 }
 
 void invept(struct vcpu *vcpu)
diff --git a/hypervisor/arch/x86/trampoline.S b/hypervisor/arch/x86/trampoline.S
index d7af62842..73036be89 100644
--- a/hypervisor/arch/x86/trampoline.S
+++ b/hypervisor/arch/x86/trampoline.S
@@ -198,21 +198,25 @@ trampoline_gdt_ptr:
 CPU_Boot_Page_Tables_ptr:
     .long CPU_Boot_Page_Tables_Start
 
-    .align  CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    .align  0x1000
     .global CPU_Boot_Page_Tables_Start
 CPU_Boot_Page_Tables_Start:
     /* 0x3 = (IA32E_COMM_P_BIT | IA32E_COMM_RW_BIT) */
     .quad   trampoline_pdpt_addr + 0x3
-    .align  CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    .align  0x1000
     .global trampoline_pdpt_addr
 trampoline_pdpt_addr:
     address = 0
     .rept   4
     /* 0x3 = (IA32E_COMM_P_BIT | IA32E_COMM_RW_BIT) */
     .quad   trampoline_pdt_addr + address + 0x3
-    address = address + CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    address = address + 0x1000
     .endr
-    .align  CPU_PAGE_SIZE
+    /*0x1000 = CPU_PAGE_SIZE*/
+    .align  0x1000
 trampoline_pdt_addr:
     address = 0
     .rept  2048
diff --git a/hypervisor/arch/x86/vmx.c b/hypervisor/arch/x86/vmx.c
index 91aa2604b..c088ad80c 100644
--- a/hypervisor/arch/x86/vmx.c
+++ b/hypervisor/arch/x86/vmx.c
@@ -1239,7 +1239,7 @@ static void init_exec_ctrl(struct vcpu *vcpu)
 			VMX_PROCBASED_CTLS2_RDTSCP |
 			VMX_PROCBASED_CTLS2_UNRESTRICT);
 
-	if (vcpu->arch_vcpu.vpid != 0)
+	if (vcpu->arch_vcpu.vpid != 0U)
 		value32 |= VMX_PROCBASED_CTLS2_VPID;
 	else
 		value32 &= ~VMX_PROCBASED_CTLS2_VPID;
diff --git a/hypervisor/include/arch/x86/guest/vcpu.h b/hypervisor/include/arch/x86/guest/vcpu.h
index c511d2efc..b574e035a 100644
--- a/hypervisor/include/arch/x86/guest/vcpu.h
+++ b/hypervisor/include/arch/x86/guest/vcpu.h
@@ -192,7 +192,7 @@ struct vcpu_arch {
 
 	/* A pointer to the VMCS for this CPU. */
 	void *vmcs;
-	int vpid;
+	uint16_t vpid;
 
 	/* Holds the information needed for IRQ/exception handling. */
 	struct {
diff --git a/hypervisor/include/arch/x86/guest/vm.h b/hypervisor/include/arch/x86/guest/vm.h
index 9479019c5..80d044e40 100644
--- a/hypervisor/include/arch/x86/guest/vm.h
+++ b/hypervisor/include/arch/x86/guest/vm.h
@@ -23,7 +23,7 @@ struct vm_attr {
 struct vm_hw_info {
 	uint16_t num_vcpus;	/* Number of total virtual cores */
 	uint16_t exp_num_vcpus;	/* Number of real expected virtual cores */
-	int created_vcpus;	/* Number of created vcpus */
+	uint16_t created_vcpus;	/* Number of created vcpus */
 	struct vcpu **vcpu_array;	/* vcpu array of this VM */
 	uint64_t gpa_lowtop;    /* top lowmem gpa of this VM */
 };
diff --git a/hypervisor/include/arch/x86/mmu.h b/hypervisor/include/arch/x86/mmu.h
index 75599b92b..4a5121527 100644
--- a/hypervisor/include/arch/x86/mmu.h
+++ b/hypervisor/include/arch/x86/mmu.h
@@ -326,8 +326,8 @@ int modify_mem(struct map_params *map_params, void *paddr, void *vaddr,
 int modify_mem_mt(struct map_params *map_params, void *paddr, void *vaddr,
 		       uint64_t size, uint32_t flags);
 int check_vmx_mmu_cap(void);
-int allocate_vpid(void);
-void flush_vpid_single(int vpid);
+uint16_t allocate_vpid(void);
+void flush_vpid_single(uint16_t vpid);
 void flush_vpid_global(void);
 void invept(struct vcpu *vcpu);
 bool check_continuous_hpa(struct vm *vm, uint64_t gpa, uint64_t size);
diff --git a/hypervisor/include/arch/x86/vmx.h b/hypervisor/include/arch/x86/vmx.h
index 93ef4d2e7..84e12fb50 100644
--- a/hypervisor/include/arch/x86/vmx.h
+++ b/hypervisor/include/arch/x86/vmx.h
@@ -314,8 +314,8 @@
 #define VMX_EPT_INVEPT_SINGLE_CONTEXT	(1U << 25)
 #define VMX_EPT_INVEPT_GLOBAL_CONTEXT	(1U << 26)
 
-#define VMX_MIN_NR_VPID			1
-#define VMX_MAX_NR_VPID			(1 << 5)
+#define VMX_MIN_NR_VPID			1U
+#define VMX_MAX_NR_VPID			(1U << 5)
 
 #define VMX_VPID_TYPE_INDIVIDUAL_ADDR	0UL
 #define VMX_VPID_TYPE_SINGLE_CONTEXT	1UL
diff --git a/hypervisor/include/lib/atomic.h b/hypervisor/include/lib/atomic.h
index 92835883d..8d557ef39 100644
--- a/hypervisor/include/lib/atomic.h
+++ b/hypervisor/include/lib/atomic.h
@@ -53,6 +53,7 @@ static inline void name(volatile type *ptr, type v)	\
 			: "r" (v)			\
 			: "cc", "memory");		\
 }
+build_atomic_store(atomic_store16, "w", uint16_t, p, v)
 build_atomic_store(atomic_store, "l", int, p, v)
 build_atomic_store(atomic_store64, "q", long, p, v)
 
@@ -73,6 +74,7 @@ static inline void name(type *ptr)			\
 			: "=m" (*ptr)			\
 			:  "m" (*ptr));			\
 }
+build_atomic_dec(atomic_dec16, "w", uint16_t, p)
 build_atomic_dec(atomic_dec, "l", int, p)
 build_atomic_dec(atomic_dec64, "q", long, p)
 
@@ -167,6 +169,7 @@ static inline type name(type *ptr, type v)			\
 			: "cc", "memory");			\
 	return v;						\
  }
+build_atomic_xadd(atomic_xadd16, "w", uint16_t, p, v)
 build_atomic_xadd(atomic_xadd, "l", int, p, v)
 build_atomic_xadd(atomic_xadd64, "q", long, p, v)