diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index 6aa0d97218..9d58a7c4ad 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -4759,6 +4759,72 @@ SpeculationBarrier (
VOID
);
+#if defined (MDE_CPU_X64) || defined (MDE_CPU_IA32)
+
+/**
+ The TDCALL instruction causes a VM exit to the Intel TDX module. It is
+ used to call guest-side Intel TDX functions, either local or a TD exit
+ to the host VMM, as selected by Leaf.
+
+ @param[in] Leaf Leaf number of TDCALL instruction
+ @param[in] Arg1 Arg1
+ @param[in] Arg2 Arg2
+ @param[in] Arg3 Arg3
+ @param[in,out] Results Returned result of the Leaf function
+
+ @return 0 A successful call
+ @return Other See individual leaf functions
+**/
+UINTN
+EFIAPI
+TdCall (
+ IN UINT64 Leaf,
+ IN UINT64 Arg1,
+ IN UINT64 Arg2,
+ IN UINT64 Arg3,
+ IN OUT VOID *Results
+ );
+
+/**
+ TDVMALL is a leaf function 0 for TDCALL. It helps invoke services from the
+ host VMM to pass/receive information.
+
+ @param[in] Leaf Number of sub-functions
+ @param[in] Arg1 Arg1
+ @param[in] Arg2 Arg2
+ @param[in] Arg3 Arg3
+ @param[in] Arg4 Arg4
+ @param[in,out] Results Returned result of the sub-function
+
+ @return 0 A successful call
+ @return Other See individual sub-functions
+
+**/
+UINTN
+EFIAPI
+TdVmCall (
+ IN UINT64 Leaf,
+ IN UINT64 Arg1,
+ IN UINT64 Arg2,
+ IN UINT64 Arg3,
+ IN UINT64 Arg4,
+ IN OUT VOID *Results
+ );
+
+/**
+ Probe if TD is enabled.
+
+ @return TRUE TD is enabled.
+ @return FALSE TD is not enabled.
+**/
+BOOLEAN
+EFIAPI
+TdIsEnabled (
+ VOID
+ );
+
+#endif
+
#if defined (MDE_CPU_X64)
//
// The page size for the PVALIDATE instruction
diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
index cebda3b210..16b7ac3917 100644
--- a/MdePkg/Library/BaseLib/BaseLib.inf
+++ b/MdePkg/Library/BaseLib/BaseLib.inf
@@ -210,6 +210,7 @@
X86RdRand.c
X86PatchInstruction.c
X86SpeculationBarrier.c
+ IntelTdxNull.c
[Sources.X64]
X64/Thunk16.nasm
@@ -293,6 +294,9 @@
X64/ReadCr0.nasm| MSFT
X64/ReadEflags.nasm| MSFT
+ X64/TdCall.nasm
+ X64/TdVmcall.nasm
+ X64/TdProbe.c
X64/Non-existing.c
Math64.c
diff --git a/MdePkg/Library/BaseLib/IntelTdxNull.c b/MdePkg/Library/BaseLib/IntelTdxNull.c
new file mode 100644
index 0000000000..ec95470bd4
--- /dev/null
+++ b/MdePkg/Library/BaseLib/IntelTdxNull.c
@@ -0,0 +1,83 @@
+/** @file
+
+ Null stub of TdxLib
+
+ Copyright (c) 2021, Intel Corporation. All rights reserved.
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include
+#include
+
+/**
+ The TDCALL instruction causes a VM exit to the Intel TDX module. It is
+ used to call guest-side Intel TDX functions, either local or a TD exit
+ to the host VMM, as selected by Leaf.
+ Leaf functions are described at
+
+ @param[in] Leaf Leaf number of TDCALL instruction
+ @param[in] Arg1 Arg1
+ @param[in] Arg2 Arg2
+ @param[in] Arg3 Arg3
+ @param[in,out] Results Returned result of the Leaf function
+
+ @return EFI_SUCCESS
+ @return Other See individual leaf functions
+**/
+UINTN
+EFIAPI
+TdCall (
+ IN UINT64 Leaf,
+ IN UINT64 Arg1,
+ IN UINT64 Arg2,
+ IN UINT64 Arg3,
+ IN OUT VOID *Results
+ )
+{
+ return EFI_UNSUPPORTED;
+}
+
+/**
+ TDVMALL is a leaf function 0 for TDCALL. It helps invoke services from the
+ host VMM to pass/receive information.
+
+ @param[in] Leaf Number of sub-functions
+ @param[in] Arg1 Arg1
+ @param[in] Arg2 Arg2
+ @param[in] Arg3 Arg3
+ @param[in] Arg4 Arg4
+ @param[in,out] Results Returned result of the sub-function
+
+ @return EFI_SUCCESS
+ @return Other See individual sub-functions
+
+**/
+UINTN
+EFIAPI
+TdVmCall (
+ IN UINT64 Leaf,
+ IN UINT64 Arg1,
+ IN UINT64 Arg2,
+ IN UINT64 Arg3,
+ IN UINT64 Arg4,
+ IN OUT VOID *Results
+ )
+{
+ return EFI_UNSUPPORTED;
+}
+
+/**
+ Probe if TD is enabled.
+
+ @return TRUE TD is enabled.
+ @return FALSE TD is not enabled.
+**/
+BOOLEAN
+EFIAPI
+TdIsEnabled (
+ )
+{
+ return FALSE;
+}
diff --git a/MdePkg/Library/BaseLib/X64/TdCall.nasm b/MdePkg/Library/BaseLib/X64/TdCall.nasm
new file mode 100644
index 0000000000..e8a094b0eb
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X64/TdCall.nasm
@@ -0,0 +1,85 @@
+;------------------------------------------------------------------------------
+;*
+;* Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.
+;* SPDX-License-Identifier: BSD-2-Clause-Patent
+;*
+;*
+;------------------------------------------------------------------------------
+
+DEFAULT REL
+SECTION .text
+
+%macro tdcall 0
+ db 0x66,0x0f,0x01,0xcc
+%endmacro
+
+%macro tdcall_push_regs 0
+ push rbp
+ mov rbp, rsp
+ push r15
+ push r14
+ push r13
+ push r12
+ push rbx
+ push rsi
+ push rdi
+%endmacro
+
+%macro tdcall_pop_regs 0
+ pop rdi
+ pop rsi
+ pop rbx
+ pop r12
+ pop r13
+ pop r14
+ pop r15
+ pop rbp
+%endmacro
+
+%define number_of_regs_pushed 8
+%define number_of_parameters 4
+
+;
+; Keep these in sync for push_regs/pop_regs, code below
+; uses them to find 5th or greater parameters
+;
+%define first_variable_on_stack_offset \
+ ((number_of_regs_pushed * 8) + (number_of_parameters * 8) + 8)
+%define second_variable_on_stack_offset \
+ ((first_variable_on_stack_offset) + 8)
+
+; TdCall (
+; UINT64 Leaf, // Rcx
+; UINT64 P1, // Rdx
+; UINT64 P2, // R8
+; UINT64 P3, // R9
+; UINT64 Results, // rsp + 0x28
+; )
+global ASM_PFX(TdCall)
+ASM_PFX(TdCall):
+ tdcall_push_regs
+
+ mov rax, rcx
+ mov rcx, rdx
+ mov rdx, r8
+ mov r8, r9
+
+ tdcall
+
+ ; exit if tdcall reports failure.
+ test rax, rax
+ jnz .exit
+
+ ; test if caller wanted results
+ mov r12, [rsp + first_variable_on_stack_offset ]
+ test r12, r12
+ jz .exit
+ mov [r12 + 0 ], rcx
+ mov [r12 + 8 ], rdx
+ mov [r12 + 16], r8
+ mov [r12 + 24], r9
+ mov [r12 + 32], r10
+ mov [r12 + 40], r11
+.exit:
+ tdcall_pop_regs
+ ret
diff --git a/MdePkg/Library/BaseLib/X64/TdProbe.c b/MdePkg/Library/BaseLib/X64/TdProbe.c
new file mode 100644
index 0000000000..b893c0a004
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X64/TdProbe.c
@@ -0,0 +1,63 @@
+/** @file
+
+ Copyright (c) 2020-2021, Intel Corporation. All rights reserved.
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include
+#include
+
+/**
+ Probe if TD is enabled.
+
+ @return TRUE TD is enabled.
+ @return FALSE TD is not enabled.
+**/
+BOOLEAN
+EFIAPI
+TdIsEnabled (
+ )
+{
+ UINT32 Eax;
+ UINT32 Ebx;
+ UINT32 Ecx;
+ UINT32 Edx;
+ UINT32 LargestEax;
+ BOOLEAN TdEnabled;
+ CPUID_VERSION_INFO_ECX CpuIdVersionInfoEcx;
+
+ TdEnabled = FALSE;
+
+ do {
+ AsmCpuid (CPUID_SIGNATURE, &LargestEax, &Ebx, &Ecx, &Edx);
+
+ if ( (Ebx != CPUID_SIGNATURE_GENUINE_INTEL_EBX)
+ || (Edx != CPUID_SIGNATURE_GENUINE_INTEL_EDX)
+ || (Ecx != CPUID_SIGNATURE_GENUINE_INTEL_ECX))
+ {
+ break;
+ }
+
+ AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, &CpuIdVersionInfoEcx.Uint32, NULL);
+ if (CpuIdVersionInfoEcx.Bits.ParaVirtualized == 0) {
+ break;
+ }
+
+ if (LargestEax < CPUID_GUESTTD_RUNTIME_ENVIRONMENT) {
+ break;
+ }
+
+ AsmCpuidEx (CPUID_GUESTTD_RUNTIME_ENVIRONMENT, 0, &Eax, &Ebx, &Ecx, &Edx);
+ if ( (Ebx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_EBX)
+ || (Edx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_EDX)
+ || (Ecx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_ECX))
+ {
+ break;
+ }
+
+ TdEnabled = TRUE;
+ } while (FALSE);
+
+ return TdEnabled;
+}
diff --git a/MdePkg/Library/BaseLib/X64/TdVmcall.nasm b/MdePkg/Library/BaseLib/X64/TdVmcall.nasm
new file mode 100644
index 0000000000..5ecc10b171
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X64/TdVmcall.nasm
@@ -0,0 +1,145 @@
+;------------------------------------------------------------------------------
+;*
+;* Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.
+;* SPDX-License-Identifier: BSD-2-Clause-Patent
+;*
+;*
+;------------------------------------------------------------------------------
+
+DEFAULT REL
+SECTION .text
+
+%define TDVMCALL_EXPOSE_REGS_MASK 0xffec
+%define TDVMCALL 0x0
+
+%macro tdcall 0
+ db 0x66,0x0f,0x01,0xcc
+%endmacro
+
+%macro tdcall_push_regs 0
+ push rbp
+ mov rbp, rsp
+ push r15
+ push r14
+ push r13
+ push r12
+ push rbx
+ push rsi
+ push rdi
+%endmacro
+
+%macro tdcall_pop_regs 0
+ pop rdi
+ pop rsi
+ pop rbx
+ pop r12
+ pop r13
+ pop r14
+ pop r15
+ pop rbp
+%endmacro
+
+%define number_of_regs_pushed 8
+%define number_of_parameters 4
+
+;
+; Keep these in sync for push_regs/pop_regs, code below
+; uses them to find 5th or greater parameters
+;
+%define first_variable_on_stack_offset \
+ ((number_of_regs_pushed * 8) + (number_of_parameters * 8) + 8)
+%define second_variable_on_stack_offset \
+ ((first_variable_on_stack_offset) + 8)
+
+%macro tdcall_regs_preamble 2
+ mov rax, %1
+
+ xor rcx, rcx
+ mov ecx, %2
+
+ ; R10 = 0 (standard TDVMCALL)
+
+ xor r10d, r10d
+
+ ; Zero out unused (for standard TDVMCALL) registers to avoid leaking
+ ; secrets to the VMM.
+
+ xor ebx, ebx
+ xor esi, esi
+ xor edi, edi
+
+ xor edx, edx
+ xor ebp, ebp
+ xor r8d, r8d
+ xor r9d, r9d
+%endmacro
+
+%macro tdcall_regs_postamble 0
+ xor ebx, ebx
+ xor esi, esi
+ xor edi, edi
+
+ xor ecx, ecx
+ xor edx, edx
+ xor r8d, r8d
+ xor r9d, r9d
+ xor r10d, r10d
+ xor r11d, r11d
+%endmacro
+
+;------------------------------------------------------------------------------
+; 0 => RAX = TDCALL leaf
+; M => RCX = TDVMCALL register behavior
+; 1 => R10 = standard vs. vendor
+; RDI => R11 = TDVMCALL function / nr
+; RSI = R12 = p1
+; RDX => R13 = p2
+; RCX => R14 = p3
+; R8 => R15 = p4
+
+; UINT64
+; EFIAPI
+; TdVmCall (
+; UINT64 Leaf, // Rcx
+; UINT64 P1, // Rdx
+; UINT64 P2, // R8
+; UINT64 P3, // R9
+; UINT64 P4, // rsp + 0x28
+; UINT64 *Val // rsp + 0x30
+; )
+global ASM_PFX(TdVmCall)
+ASM_PFX(TdVmCall):
+ tdcall_push_regs
+
+ mov r11, rcx
+ mov r12, rdx
+ mov r13, r8
+ mov r14, r9
+ mov r15, [rsp + first_variable_on_stack_offset ]
+
+ tdcall_regs_preamble TDVMCALL, TDVMCALL_EXPOSE_REGS_MASK
+
+ tdcall
+
+ ; ignore return dataif TDCALL reports failure.
+ test rax, rax
+ jnz .no_return_data
+
+ ; Propagate TDVMCALL success/failure to return value.
+ mov rax, r10
+
+ ; Retrieve the Val pointer.
+ mov r9, [rsp + second_variable_on_stack_offset ]
+ test r9, r9
+ jz .no_return_data
+
+ ; On success, propagate TDVMCALL output value to output param
+ test rax, rax
+ jnz .no_return_data
+ mov [r9], r11
+.no_return_data:
+ tdcall_regs_postamble
+
+ tdcall_pop_regs
+
+ ret