diff --git a/hypervisor/arch/x86/Kconfig b/hypervisor/arch/x86/Kconfig
index 292754a4f..0cbdff92a 100644
--- a/hypervisor/arch/x86/Kconfig
+++ b/hypervisor/arch/x86/Kconfig
@@ -74,15 +74,9 @@ config MEM_LOGLEVEL_DEFAULT
 	int "Default loglevel in memory"
 	default 4
 
-config LOW_RAM_START
-	hex "Address of the beginning of low RAM region"
-	default 0x00001000 if PLATFORM_SBL
-	default 0x00008000 if PLATFORM_UEFI
-
 config LOW_RAM_SIZE
 	hex "Size of the low RAM region"
-	default 0x000cf000 if PLATFORM_SBL
-	default 0x00010000 if PLATFORM_UEFI
+	default 0x00010000
 
 config RAM_START
 	hex "Address of the RAM region assigned to the hypervisor"
diff --git a/hypervisor/arch/x86/cpu.c b/hypervisor/arch/x86/cpu.c
index d61d439ae..9bfe54948 100644
--- a/hypervisor/arch/x86/cpu.c
+++ b/hypervisor/arch/x86/cpu.c
@@ -26,6 +26,8 @@ volatile uint32_t up_count = 0;
 /* physical cpu active bitmap, support up to 64 cpus */
 uint64_t pcpu_active_bitmap = 0;
 
+uint64_t trampline_start16_paddr;
+
 /* TODO: add more capability per requirement */
 /*APICv features*/
 #define VAPIC_FEATURE_VIRT_ACCESS		(1 << 0)
diff --git a/hypervisor/arch/x86/guest/guest.c b/hypervisor/arch/x86/guest/guest.c
index 8329d5f55..998eacde8 100644
--- a/hypervisor/arch/x86/guest/guest.c
+++ b/hypervisor/arch/x86/guest/guest.c
@@ -674,9 +674,8 @@ uint64_t e820_alloc_low_memory(uint32_t size)
  * This API assume that the trusty memory is remapped to guest physical address
  * of 511G to 511G + 16MB
  *
- * FIXME: here using hard code GUEST_INIT_PAGE_TABLE_START as guest init page
- * table gpa start, and it will occupy at most GUEST_INIT_PT_PAGE_NUM pages.
- * Some check here:
+ * FIXME: here the guest init page table will occupy at most
+ * GUEST_INIT_PT_PAGE_NUM pages. Some check here:
  * - guest page table space should not override trampline code area
  *   (it's a little tricky here, as under current identical mapping, HV & SOS
  *   share same memory under 1M; under uefi boot mode, the defered AP startup
@@ -688,7 +687,7 @@ uint64_t e820_alloc_low_memory(uint32_t size)
  * after guest realmode/32bit no paging mode got supported.
  ******************************************************************/
 #define GUEST_INIT_PAGE_TABLE_SKIP_SIZE	0x8000UL
-#define GUEST_INIT_PAGE_TABLE_START	(CONFIG_LOW_RAM_START +	\
+#define GUEST_INIT_PAGE_TABLE_START	(trampline_start16_paddr +	\
 					GUEST_INIT_PAGE_TABLE_SKIP_SIZE)
 #define GUEST_INIT_PT_PAGE_NUM		7
 #define RSDP_F_ADDR			0xE0000
@@ -794,7 +793,7 @@ uint64_t create_guest_initial_paging(struct vm *vm)
  ******************************************************************/
 
 #define GUEST_INIT_GDT_SKIP_SIZE	0x8000UL
-#define GUEST_INIT_GDT_START	(CONFIG_LOW_RAM_START +	\
+#define GUEST_INIT_GDT_START	(trampline_start16_paddr +	\
 					GUEST_INIT_GDT_SKIP_SIZE)
 
 /* The GDT defined below compatible with linux kernel */
diff --git a/hypervisor/bsp/sbl/include/bsp/bsp_cfg.h b/hypervisor/bsp/sbl/include/bsp/bsp_cfg.h
index c9399415c..d7cc67c18 100644
--- a/hypervisor/bsp/sbl/include/bsp/bsp_cfg.h
+++ b/hypervisor/bsp/sbl/include/bsp/bsp_cfg.h
@@ -17,8 +17,7 @@
 #define HEAP_SIZE	0x100000
 #define CONSOLE_LOGLEVEL_DEFAULT	3
 #define MEM_LOGLEVEL_DEFAULT		5
-#define	CONFIG_LOW_RAM_START	0x00001000
-#define	CONFIG_LOW_RAM_SIZE	0x000CF000
+#define	CONFIG_LOW_RAM_SIZE	0x00010000
 #define	CONFIG_RAM_START	0x6E000000
 #define	CONFIG_RAM_SIZE		0x02000000	/* 32M */
 #define CONFIG_MTRR_ENABLED     1
diff --git a/hypervisor/bsp/uefi/efi/boot.c b/hypervisor/bsp/uefi/efi/boot.c
index e4ffe3f3c..b9ffd93b4 100644
--- a/hypervisor/bsp/uefi/efi/boot.c
+++ b/hypervisor/bsp/uefi/efi/boot.c
@@ -190,12 +190,6 @@ again:
 	mmap[j].mm_type = E820_RAM;
 	j++;
 
-	/* reserve secondary memory region(0x1000 ~ 0x10000) for hv */
-	err = __emalloc(CONFIG_LOW_RAM_SIZE, CONFIG_LOW_RAM_START,
-		&addr, EfiReservedMemoryType);
-	if (err != EFI_SUCCESS)
-		goto out;
-
 	mbi->mi_flags |= MULTIBOOT_INFO_HAS_MMAP | MULTIBOOT_INFO_HAS_CMDLINE;
 	mbi->mi_mmap_length = j*sizeof(struct multiboot_mmap);
 
@@ -227,6 +221,13 @@ switch_to_guest_mode(EFI_HANDLE image)
 
 	efi_ctx = (struct efi_ctx *)(UINTN)addr;
 
+	/* reserve secondary memory region for hv */
+	err = emalloc_for_low_mem(&addr, CONFIG_LOW_RAM_SIZE);
+	if (err != EFI_SUCCESS)
+		goto out;
+
+	efi_ctx->ap_trampline_buf = (void *)addr;
+
 	config_table = sys_table->ConfigurationTable;
 
 	for (i = 0; i < sys_table->NumberOfTableEntries; i++) {
diff --git a/hypervisor/bsp/uefi/efi/boot.h b/hypervisor/bsp/uefi/efi/boot.h
index abd307a59..e223ee3f9 100644
--- a/hypervisor/bsp/uefi/efi/boot.h
+++ b/hypervisor/bsp/uefi/efi/boot.h
@@ -95,6 +95,7 @@ struct e820_entry {
 struct efi_ctx {
 	uint64_t rip;
 	VOID *rsdp;
+	VOID *ap_trampline_buf;
 	dt_addr_t  gdt;
 	dt_addr_t  idt;
 	uint16_t   tr_sel;
diff --git a/hypervisor/bsp/uefi/include/bsp/bsp_cfg.h b/hypervisor/bsp/uefi/include/bsp/bsp_cfg.h
index a882f32bd..d9e926e42 100644
--- a/hypervisor/bsp/uefi/include/bsp/bsp_cfg.h
+++ b/hypervisor/bsp/uefi/include/bsp/bsp_cfg.h
@@ -17,7 +17,6 @@
 #define HEAP_SIZE	0x100000
 #define CONSOLE_LOGLEVEL_DEFAULT	3
 #define MEM_LOGLEVEL_DEFAULT		5
-#define	CONFIG_LOW_RAM_START	0x00008000
 #define	CONFIG_LOW_RAM_SIZE	0x00010000
 #define	CONFIG_RAM_START	0x20000000
 #define	CONFIG_RAM_SIZE		0x02000000	/* 32M */
diff --git a/hypervisor/bsp/uefi/uefi.c b/hypervisor/bsp/uefi/uefi.c
index 1a4a3ccb2..fd27845c2 100644
--- a/hypervisor/bsp/uefi/uefi.c
+++ b/hypervisor/bsp/uefi/uefi.c
@@ -97,6 +97,11 @@ void *get_rsdp_from_uefi(void)
 	return HPA2HVA(efi_ctx->rsdp);
 }
 
+void *get_ap_trampline_buf(void)
+{
+	return efi_ctx->ap_trampline_buf;
+}
+
 static void efi_init(void)
 {
 	struct multiboot_info *mbi = NULL;
diff --git a/hypervisor/include/arch/x86/cpu.h b/hypervisor/include/arch/x86/cpu.h
index a3943c6fe..501050f0c 100644
--- a/hypervisor/include/arch/x86/cpu.h
+++ b/hypervisor/include/arch/x86/cpu.h
@@ -169,6 +169,7 @@ extern uint8_t                trampline_pdpt_addr[];
 extern uint8_t                trampline_gdt_ptr[];
 extern uint8_t                trampline_start64_fixup[];
 
+extern uint64_t trampline_start16_paddr;
 extern int ibrs_type;
 
 /*
diff --git a/hypervisor/include/common/acrn_efi.h b/hypervisor/include/common/acrn_efi.h
index 86abf0377..21ebd1630 100644
--- a/hypervisor/include/common/acrn_efi.h
+++ b/hypervisor/include/common/acrn_efi.h
@@ -15,6 +15,7 @@ typedef struct {
 struct efi_ctx {
 	uint64_t rip;
 	void *rsdp;
+	void *ap_trampline_buf;
 	dt_addr_t  gdt;
 	dt_addr_t  idt;
 	uint16_t   tr_sel;
@@ -50,5 +51,6 @@ struct efi_ctx {
 }__attribute__((packed));
 
 void *get_rsdp_from_uefi(void);
+void *get_ap_trampline_buf(void);
 
 #endif /* UEFI_H*/