diff --git a/hypervisor/arch/x86/guest/vcpuid.c b/hypervisor/arch/x86/guest/vcpuid.c
index 5718f2911..21e9e1d13 100644
--- a/hypervisor/arch/x86/guest/vcpuid.c
+++ b/hypervisor/arch/x86/guest/vcpuid.c
@@ -315,6 +315,9 @@ void guest_cpuid(struct acrn_vcpu *vcpu, uint32_t *eax, uint32_t *ebx, uint32_t
 			*edx &= ~CPUID_EDX_MTRR;
 #endif
 
+			/* mask Safer Mode Extension */
+			*ecx &= ~CPUID_ECX_SMX;
+
 			/* mask pcid */
 			*ecx &= ~CPUID_ECX_PCID;
 
diff --git a/hypervisor/arch/x86/guest/vmsr.c b/hypervisor/arch/x86/guest/vmsr.c
index dd4064a89..bc5bf4446 100644
--- a/hypervisor/arch/x86/guest/vmsr.c
+++ b/hypervisor/arch/x86/guest/vmsr.c
@@ -53,7 +53,7 @@ static const uint32_t mtrr_msrs[NUM_MTRR_MSRS] = {
 };
 
 /* Following MSRs are intercepted, but it throws GPs for any guest accesses */
-#define NUM_UNSUPPORTED_MSRS	95U
+#define NUM_UNSUPPORTED_MSRS	96U
 static const uint32_t unsupported_msrs[NUM_UNSUPPORTED_MSRS] = {
 	/* Variable MTRRs are not supported */
 	MSR_IA32_MTRR_PHYSBASE_0,
@@ -173,6 +173,9 @@ static const uint32_t unsupported_msrs[NUM_UNSUPPORTED_MSRS] = {
 	MSR_IA32_RTIT_ADDR2_B,
 	MSR_IA32_RTIT_ADDR3_A,
 	MSR_IA32_RTIT_ADDR3_B,
+
+	/* SMM Monitor Configuration: CPUID.01H.ECX[5] and CPUID.01H.ECX[6] */
+	MSR_IA32_SMM_MONITOR_CTL,
 };
 
 #define NUM_X2APIC_MSRS	44U
diff --git a/hypervisor/arch/x86/vmcs.c b/hypervisor/arch/x86/vmcs.c
index 033e3565f..bd2657d46 100644
--- a/hypervisor/arch/x86/vmcs.c
+++ b/hypervisor/arch/x86/vmcs.c
@@ -281,8 +281,8 @@ static bool is_cr4_write_valid(struct acrn_vcpu *vcpu, uint64_t cr4)
 	if ((cr4 & cr4_always_off_mask) != 0U) {
 		ret = false;
 	} else {
-		/* Do NOT support nested guest */
-		if ((cr4 & CR4_VMXE) != 0UL) {
+		/* Do NOT support nested guest, nor SMX */
+		if (((cr4 & CR4_VMXE) != 0UL) || ((cr4 & CR4_SMXE) != 0UL)) {
 			ret = false;
 		} else {
 			/* Do NOT support PCID in guest */
@@ -417,7 +417,7 @@ static void init_guest_state(struct acrn_vcpu *vcpu)
 		&vcpu->arch.contexts[vcpu->arch.cur_context];
 
 	init_guest_vmx(vcpu, ctx->run_ctx.cr0, ctx->ext_ctx.cr3,
-			ctx->run_ctx.cr4 & ~CR4_VMXE);
+			ctx->run_ctx.cr4 & ~(CR4_VMXE | CR4_SMXE));
 }
 
 static void init_host_state(void)