diff --git a/hypervisor/arch/x86/guest/vcpu.c b/hypervisor/arch/x86/guest/vcpu.c
index cc66bbb8e..2a27d9b73 100644
--- a/hypervisor/arch/x86/guest/vcpu.c
+++ b/hypervisor/arch/x86/guest/vcpu.c
@@ -263,6 +263,51 @@ void set_ap_entry(struct vcpu *vcpu, uint64_t entry)
 	vcpu_set_rip(vcpu, 0UL);
 }
 
+
+/* NOTE: set_bsp_real_mode_entry & set_bsp_protect_mode_regs is only temporary
+ * function called by UOS. Once we make UOS to use hypercall to set BSP entry,
+ * we will remove these two functions.
+ */
+
+/*
+ * @pre reset_vcpu_regs is called in advance
+ */
+void set_bsp_real_mode_entry(struct vcpu *vcpu)
+{
+	struct ext_context *ectx;
+
+	ectx = &(vcpu->arch_vcpu.contexts[vcpu->arch_vcpu.cur_context].ext_ctx);
+
+	ectx->cs.selector = REAL_MODE_BSP_INIT_CODE_SEL;
+	ectx->cs.base = 0x3ff0000UL;
+	vcpu_set_rip(vcpu, 0xFFF0UL);
+}
+
+static struct acrn_vcpu_regs protect_mode_init_regs = {
+	.cs_ar = PROTECTED_MODE_CODE_SEG_AR,
+	.cs_sel = 0x10U,
+	.ss_sel = 0x18U,
+	.ds_sel = 0x18U,
+	.es_sel = 0x18U,
+	.cr0 = CR0_ET | CR0_NE | CR0_PE,
+	.cr3 = 0UL,
+	.cr4 = 0UL,
+};
+
+void set_bsp_protect_mode_regs(struct vcpu *vcpu)
+{
+	/* if vcpu is in protect mode, we need to set registers
+	 * according to protect_init_regs first.
+	 */
+	uint32_t limit;
+	protect_mode_init_regs.gdt.base = create_guest_init_gdt(vcpu->vm,
+			&limit);
+	protect_mode_init_regs.gdt.limit = (uint16_t) (limit & 0xFFFFU);
+	set_vcpu_regs(vcpu, &protect_mode_init_regs);
+
+	vcpu_set_rip(vcpu, (uint64_t)vcpu->entry_addr);
+}
+
 /***********************************************************************
  *
  *  @pre vm != NULL && rtn_vcpu_handle != NULL
@@ -593,8 +638,7 @@ int prepare_vcpu(struct vm *vm, uint16_t pcpu_id)
 			vcpu->arch_vcpu.cpu_mode = CPU_MODE_PROTECTED;
 #else
 		if (is_vm0(vcpu->vm)) {
-			struct acrn_vcpu_regs *vm0_init_ctx =
-				(struct acrn_vcpu_regs *)(&vm0_boot_context);
+			struct acrn_vcpu_regs *vm0_init_ctx = &vm0_boot_context;
 			/* VM0 bsp start mode is decided by the boot context
 			 * setup by bootloader / bios */
 			if ((vm0_init_ctx->ia32_efer & MSR_IA32_EFER_LMA_BIT) &&
diff --git a/hypervisor/arch/x86/guest/vm.c b/hypervisor/arch/x86/guest/vm.c
index bedf4cfea..f978650c7 100644
--- a/hypervisor/arch/x86/guest/vm.c
+++ b/hypervisor/arch/x86/guest/vm.c
@@ -304,11 +304,11 @@ int reset_vm(struct vm *vm)
 
 	foreach_vcpu(i, vm, vcpu) {
 		reset_vcpu(vcpu);
+
+		vcpu->arch_vcpu.cpu_mode = CPU_MODE_REAL;
 		if (is_vcpu_bsp(vcpu)) {
 			vm_sw_loader(vm, vcpu);
 		}
-
-		vcpu->arch_vcpu.cpu_mode = CPU_MODE_REAL;
 	}
 
 	vioapic_reset(vm_ioapic(vm));
diff --git a/hypervisor/arch/x86/vmx.c b/hypervisor/arch/x86/vmx.c
index 90faead5a..864a34a60 100644
--- a/hypervisor/arch/x86/vmx.c
+++ b/hypervisor/arch/x86/vmx.c
@@ -673,8 +673,7 @@ static void init_guest_state(struct vcpu *vcpu)
 {
 	struct cpu_context *ctx =
 		&vcpu->arch_vcpu.contexts[vcpu->arch_vcpu.cur_context];
-	struct acrn_vcpu_regs* init_ctx =
-		(struct acrn_vcpu_regs*)(&vm0_boot_context);
+	struct acrn_vcpu_regs* init_ctx = &vm0_boot_context;
 	enum vm_cpu_mode vcpu_mode = get_vcpu_mode(vcpu);
 
 	vcpu_set_rflags(vcpu, 0x2UL); /* Bit 1 is a active high reserved bit */
diff --git a/hypervisor/bsp/uefi/uefi.c b/hypervisor/bsp/uefi/uefi.c
index dda032f9f..50af6e95a 100644
--- a/hypervisor/bsp/uefi/uefi.c
+++ b/hypervisor/bsp/uefi/uefi.c
@@ -39,8 +39,7 @@ void efi_spurious_handler(int vector)
 int uefi_sw_loader(struct vm *vm, struct vcpu *vcpu)
 {
 	int ret = 0;
-	struct acrn_vcpu_regs *vcpu_regs =
-		(struct acrn_vcpu_regs *)&vm0_boot_context;
+	struct acrn_vcpu_regs *vcpu_regs = &vm0_boot_context;
 
 	ASSERT(vm != NULL, "Incorrect argument");
 
diff --git a/hypervisor/common/vm_load.c b/hypervisor/common/vm_load.c
index 87565705e..681d08c8a 100644
--- a/hypervisor/common/vm_load.c
+++ b/hypervisor/common/vm_load.c
@@ -88,21 +88,22 @@ static uint64_t create_zero_page(struct vm *vm)
 int load_guest(struct vm *vm, struct vcpu *vcpu)
 {
 	int32_t ret = 0;
-	uint32_t i;
 	void *hva;
 	uint64_t  lowmem_gpa_top;
 
 	hva  = gpa2hva(vm, GUEST_CFG_OFFSET);
 	lowmem_gpa_top = *(uint64_t *)hva;
 
-	/* hardcode vcpu entry addr(kernel entry) & rsi (zeropage)*/
-	for (i = 0U; i < NUM_GPRS; i++) {
-		vcpu_set_gpreg(vcpu, i, 0UL);
-	}
-
 	hva  = gpa2hva(vm, lowmem_gpa_top -
 			MEM_4K - MEM_2K);
 	vcpu->entry_addr = (void *)(*((uint64_t *)hva));
+
+	if (get_vcpu_mode(vcpu) == CPU_MODE_REAL) {
+		set_bsp_real_mode_entry(vcpu);
+	} else {
+		set_bsp_protect_mode_regs(vcpu);
+	}
+
 	vcpu_set_gpreg(vcpu, CPU_REG_RSI, lowmem_gpa_top - MEM_4K);
 
 	pr_info("%s, Set config according to predefined offset:",
@@ -138,7 +139,7 @@ int general_sw_loader(struct vm *vm, struct vcpu *vcpu)
 	}
 #endif
 
-	set_vcpu_regs(vcpu, (struct acrn_vcpu_regs *)&vm0_boot_context);
+	set_vcpu_regs(vcpu, &vm0_boot_context);
 
 	/* calculate the kernel entry point */
 	zeropage = (struct zero_page *)sw_kernel->kernel_src_addr;
diff --git a/hypervisor/include/arch/x86/guest/guest.h b/hypervisor/include/arch/x86/guest/guest.h
index 9ea1430c0..de89d83e8 100644
--- a/hypervisor/include/arch/x86/guest/guest.h
+++ b/hypervisor/include/arch/x86/guest/guest.h
@@ -163,7 +163,7 @@ int copy_to_gva(struct vcpu *vcpu, void *h_ptr, uint64_t gva,
 	uint32_t size, uint32_t *err_code, uint64_t *fault_addr);
 
 uint64_t create_guest_init_gdt(struct vm *vm, uint32_t *limit);
-extern uint8_t vm0_boot_context;
+extern struct acrn_vcpu_regs vm0_boot_context;
 
 #endif	/* !ASSEMBLER */
 
diff --git a/hypervisor/include/arch/x86/guest/vcpu.h b/hypervisor/include/arch/x86/guest/vcpu.h
index 1c4d3e1bd..9312bfaa0 100644
--- a/hypervisor/include/arch/x86/guest/vcpu.h
+++ b/hypervisor/include/arch/x86/guest/vcpu.h
@@ -288,6 +288,8 @@ void vcpu_set_pat_ext(struct vcpu *vcpu, uint64_t val);
 void set_vcpu_regs(struct vcpu *vcpu, struct acrn_vcpu_regs *vcpu_regs);
 void reset_vcpu_regs(struct vcpu *vcpu);
 void set_ap_entry(struct vcpu *vcpu, uint64_t entry);
+void set_bsp_real_mode_entry(struct vcpu *vcpu);
+void set_bsp_protect_mode_regs(struct vcpu *vcpu);
 
 static inline bool is_long_mode(struct vcpu *vcpu)
 {