[PATCH V3 02/29] MdePkg: Add TdxLib to wrap Tdx operations

["Min Xu" <min.m.xu@intel.com>]

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

TdxLib is created with functions to perform the related Tdx operation.
This includes functions for:
 - TdCall          : Cause a VM exit to the Intel TDX module.
 - TdVmCall        : It helps invoke services from the host VMM to pass/
                     receive information.
 - TdVmCallCpuid   : Enable the TD guest to request VMM to emulate CPUID
 - TdAcceptPages   : Accept pending private pages and initialize the pages
                     to all-0 using the TD ephemeral private key.
 - TdExtendRtmr    : Extend measurement to one of the RTMR registers.
 - TdSharedPageMask: Get the Td guest shared page mask which indicates it
                     is a Shared or Private page.
 - TdMaxVCpuNum    : Get the maximum number of virtual CPUs.
 - TdVCpuNum       : Get the number of virtual CPUs.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 MdePkg/Include/Library/TdxLib.h         | 167 +++++++++++++++++++
 MdePkg/Library/TdxLib/AcceptPages.c     | 137 ++++++++++++++++
 MdePkg/Library/TdxLib/Rtmr.c            |  83 ++++++++++
 MdePkg/Library/TdxLib/TdInfo.c          | 103 ++++++++++++
 MdePkg/Library/TdxLib/TdxLib.inf        |  39 +++++
 MdePkg/Library/TdxLib/TdxLibNull.c      | 192 ++++++++++++++++++++++
 MdePkg/Library/TdxLib/X64/Tdcall.nasm   |  85 ++++++++++
 MdePkg/Library/TdxLib/X64/Tdvmcall.nasm | 207 ++++++++++++++++++++++++
 MdePkg/MdePkg.dec                       |   3 +
 MdePkg/MdePkg.dsc                       |   1 +
 10 files changed, 1017 insertions(+)
 create mode 100644 MdePkg/Include/Library/TdxLib.h
 create mode 100644 MdePkg/Library/TdxLib/AcceptPages.c
 create mode 100644 MdePkg/Library/TdxLib/Rtmr.c
 create mode 100644 MdePkg/Library/TdxLib/TdInfo.c
 create mode 100644 MdePkg/Library/TdxLib/TdxLib.inf
 create mode 100644 MdePkg/Library/TdxLib/TdxLibNull.c
 create mode 100644 MdePkg/Library/TdxLib/X64/Tdcall.nasm
 create mode 100644 MdePkg/Library/TdxLib/X64/Tdvmcall.nasm

diff --git a/MdePkg/Include/Library/TdxLib.h b/MdePkg/Include/Library/TdxLib.h
new file mode 100644
index 000000000000..d9e0335b2300
--- /dev/null
+++ b/MdePkg/Include/Library/TdxLib.h
@@ -0,0 +1,167 @@
+/** @file
+  TdxLib definitions
+
+  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef TDX_LIB_H_
+#define TDX_LIB_H_
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Uefi/UefiBaseType.h>
+#include <Protocol/DebugSupport.h>
+
+/**
+  This function accepts a pending private page, and initialize the page to
+  all-0 using the TD ephemeral private key.
+
+  @param[in]  StartAddress     Guest physical address of the private page
+                               to accept.
+  @param[in]  NumberOfPages    Number of the pages to be accepted.
+  @param[in]  PageSize         GPA page size. Accept 2M/4K page size.
+
+  @return EFI_SUCCESS
+**/
+EFI_STATUS
+EFIAPI
+TdAcceptPages (
+  IN UINT64  StartAddress,
+  IN UINT64  NumberOfPages,
+  IN UINT32  PageSize
+  );
+
+/**
+  This function extends one of the RTMR measurement register
+  in TDCS with the provided extension data in memory.
+  RTMR extending supports SHA384 which length is 48 bytes.
+
+  @param[in]  Data      Point to the data to be extended
+  @param[in]  DataLen   Length of the data. Must be 48
+  @param[in]  Index     RTMR index
+
+  @return EFI_SUCCESS
+  @return EFI_INVALID_PARAMETER
+  @return EFI_DEVICE_ERROR
+
+**/
+EFI_STATUS
+EFIAPI
+TdExtendRtmr (
+  IN  UINT32  *Data,
+  IN  UINT32  DataLen,
+  IN  UINT8   Index
+  );
+
+
+/**
+  This function gets the Td guest shared page mask.
+
+  The guest indicates if a page is shared using the Guest Physical Address
+  (GPA) Shared (S) bit. If the GPA Width(GPAW) is 48, the S-bit is bit-47.
+  If the GPAW is 52, the S-bit is bit-51.
+
+  @return Shared page bit mask
+**/
+UINT64
+EFIAPI
+TdSharedPageMask (
+  VOID
+  );
+
+/**
+  This function gets the maximum number of Virtual CPUs that are usable for
+  Td Guest.
+
+  @return maximum Virtual CPUs number
+**/
+UINT32
+EFIAPI
+TdMaxVCpuNum (
+  VOID
+  );
+
+/**
+  This function gets the number of Virtual CPUs that are usable for Td
+  Guest.
+
+  @return Virtual CPUs number
+**/
+UINT32
+EFIAPI
+TdVCpuNum (
+  VOID
+  );
+
+
+/**
+  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 EFI_SUCCESS
+  @return Other           See individual leaf functions
+**/
+EFI_STATUS
+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 EFI_SUCCESS
+  @return Other           See individual sub-functions
+
+**/
+EFI_STATUS
+EFIAPI
+TdVmCall (
+  IN UINT64          Leaf,
+  IN UINT64          Arg1,
+  IN UINT64          Arg2,
+  IN UINT64          Arg3,
+  IN UINT64          Arg4,
+  IN OUT VOID        *Results
+  );
+
+/**
+  This function enable the TD guest to request the VMM to emulate CPUID
+  operation, especially for non-architectural, CPUID leaves.
+
+  @param[in]  Eax        Main leaf of the CPUID
+  @param[in]  Ecx        Sub-leaf of the CPUID
+  @param[out] Results    Returned result of CPUID operation
+
+  @return EFI_SUCCESS
+**/
+EFI_STATUS
+EFIAPI
+TdVmCallCpuid (
+  IN UINT64         Eax,
+  IN UINT64         Ecx,
+  OUT VOID          *Results
+  );
+
+#endif
diff --git a/MdePkg/Library/TdxLib/AcceptPages.c b/MdePkg/Library/TdxLib/AcceptPages.c
new file mode 100644
index 000000000000..18e94b13c351
--- /dev/null
+++ b/MdePkg/Library/TdxLib/AcceptPages.c
@@ -0,0 +1,137 @@
+/** @file
+
+  Unaccepted memory is a special type of private memory. In Td guest
+  TDCALL [TDG.MEM.PAGE.ACCEPT] is invoked to accept the unaccepted
+  memory before use it.
+
+  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <IndustryStandard/Tdx.h>
+#include <Library/TdxLib.h>
+#include <Library/BaseMemoryLib.h>
+
+UINT64  mNumberOfDuplicatedAcceptedPages;
+
+// PageSize is mapped to PageLevel like below:
+// 4KB - 0, 2MB - 1
+UINT32  mTdxAcceptPageLevelMap[2] = {
+  SIZE_4KB,
+  SIZE_2MB
+};
+
+/**
+  This function gets the PageLevel according to the input page size.
+
+  @param[in]  PageSize    Page size
+
+  @return UINT32          The mapped page level
+**/
+UINT32
+GetGpaPageLevel (
+  UINT32 PageSize
+  )
+{
+  UINT32 Index;
+
+  for (Index = 0; Index < ARRAY_SIZE (mTdxAcceptPageLevelMap); Index++) {
+    if (mTdxAcceptPageLevelMap[Index] == PageSize) {
+      break;
+    }
+  }
+
+  return Index == ARRAY_SIZE (mTdxAcceptPageLevelMap) ? -1 : Index;
+}
+
+/**
+  This function accept a pending private page, and initialize the page to
+  all-0 using the TD ephemeral private key.
+
+  Sometimes TDCALL [TDG.MEM.PAGE.ACCEPT] may return
+  TDX_EXIT_REASON_PAGE_SIZE_MISMATCH. It indicates the input PageLevel is
+  not workable. In this case we need to try to fallback to a smaller
+  PageLevel if possible.
+
+  @param[in]  StartAddress      Guest physical address of the private
+                                page to accept.
+  @param[in]  NumberOfPages     Number of the pages to be accepted.
+  @param[in]  PageSize          GPA page size. Only accept 1G/2M/4K size.
+
+  @return EFI_SUCCESS           Accept successfully
+  @return others                Indicate other errors
+**/
+EFI_STATUS
+EFIAPI
+TdAcceptPages (
+  IN UINT64  StartAddress,
+  IN UINT64  NumberOfPages,
+  IN UINT32  PageSize
+  )
+{
+  EFI_STATUS  Status;
+  UINT64      Address;
+  UINT64      TdxStatus;
+  UINT64      Index;
+  UINT32      GpaPageLevel;
+  UINT32      PageSize2;
+
+  Address = StartAddress;
+
+  GpaPageLevel = GetGpaPageLevel (PageSize);
+  if (GpaPageLevel == -1) {
+    DEBUG ((DEBUG_ERROR, "Accept page size must be 4K/2M. Invalid page size - 0x%llx\n", PageSize));
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = EFI_SUCCESS;
+  for (Index = 0; Index < NumberOfPages; Index++) {
+    TdxStatus = TdCall (TDCALL_TDACCEPTPAGE, Address | GpaPageLevel, 0, 0, 0);
+    if (TdxStatus != TDX_EXIT_REASON_SUCCESS) {
+        if ((TdxStatus & ~0xFFFFULL) == TDX_EXIT_REASON_PAGE_ALREADY_ACCEPTED) {
+          //
+          // Already accepted
+          //
+          mNumberOfDuplicatedAcceptedPages++;
+          DEBUG ((DEBUG_WARN, "Page at Address (0x%llx) has already been accepted. - %d\n", Address, mNumberOfDuplicatedAcceptedPages));
+        } else if ((TdxStatus & ~0xFFFFULL) == TDX_EXIT_REASON_PAGE_SIZE_MISMATCH) {
+          //
+          // GpaPageLevel is mismatch, fall back to a smaller GpaPageLevel if possible
+          //
+          DEBUG ((DEBUG_VERBOSE, "Address %llx cannot be accepted in PageLevel of %d\n", Address, GpaPageLevel));
+
+          if (GpaPageLevel == 0) {
+            //
+            // Cannot fall back to smaller page level
+            //
+            DEBUG ((DEBUG_ERROR, "AcceptPage cannot fallback from PageLevel %d\n", GpaPageLevel));
+            Status = EFI_INVALID_PARAMETER;
+            break;
+          } else {
+            //
+            // Fall back to a smaller page size
+            //
+            PageSize2 = mTdxAcceptPageLevelMap [GpaPageLevel - 1];
+            Status = TdAcceptPages(Address, 512, PageSize2);
+            if (EFI_ERROR (Status)) {
+              break;
+            }
+          }
+        }else {
+
+          //
+          // Other errors
+          //
+          DEBUG ((DEBUG_ERROR, "Address %llx (%d) failed to be accepted. Error = 0x%llx\n",
+            Address, Index, TdxStatus));
+          Status = EFI_INVALID_PARAMETER;
+          break;
+        }
+    }
+    Address += PageSize;
+  }
+  return Status;
+}
diff --git a/MdePkg/Library/TdxLib/Rtmr.c b/MdePkg/Library/TdxLib/Rtmr.c
new file mode 100644
index 000000000000..42e85eb9d9bb
--- /dev/null
+++ b/MdePkg/Library/TdxLib/Rtmr.c
@@ -0,0 +1,83 @@
+/** @file
+
+  Extends one of the RTMR measurement registers in TDCS with the provided
+  extension data in memory.
+
+  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/TdxLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <IndustryStandard/Tpm20.h>
+#include <IndustryStandard/Tdx.h>
+
+#define RTMR_COUNT                  4
+#define TD_EXTEND_BUFFER_LEN        (64 + 48)
+
+UINT8   mExtendBuffer[TD_EXTEND_BUFFER_LEN];
+
+/**
+  This function extends one of the RTMR measurement register
+  in TDCS with the provided extension data in memory.
+  RTMR extending supports SHA384 which length is 48 bytes.
+
+  @param[in]  Data      Point to the data to be extended
+  @param[in]  DataLen   Length of the data. Must be 48
+  @param[in]  Index     RTMR index
+
+  @return EFI_SUCCESS
+  @return EFI_INVALID_PARAMETER
+  @return EFI_DEVICE_ERROR
+
+**/
+EFI_STATUS
+EFIAPI
+TdExtendRtmr (
+  IN  UINT32  *Data,
+  IN  UINT32  DataLen,
+  IN  UINT8   Index
+  )
+{
+  EFI_STATUS            Status;
+  UINT64                TdCallStatus;
+  UINT8                 *ExtendBuffer;
+
+  Status = EFI_SUCCESS;
+
+  ASSERT (Data != NULL);
+  ASSERT (DataLen == SHA384_DIGEST_SIZE);
+  ASSERT (Index >= 0 && Index < RTMR_COUNT);
+
+  if (Data == NULL || DataLen != SHA384_DIGEST_SIZE || Index >= RTMR_COUNT) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  // TD.RTMR.EXTEND requires 64B-aligned guest physical address of
+  // 48B-extension data. We use ALIGN_POINTER(Pointer, 64) to get
+  // the 64B-aligned guest physical address.
+  ExtendBuffer = ALIGN_POINTER (mExtendBuffer, 64);
+  ASSERT (((UINTN)ExtendBuffer & 0x3f) == 0 );
+
+  ZeroMem (ExtendBuffer, SHA384_DIGEST_SIZE);
+  CopyMem (ExtendBuffer, Data, SHA384_DIGEST_SIZE);
+
+  TdCallStatus = TdCall (TDCALL_TDEXTENDRTMR, (UINT64)(UINTN)ExtendBuffer, Index, 0, 0);
+
+  if (TdCallStatus == TDX_EXIT_REASON_SUCCESS) {
+    Status = EFI_SUCCESS;
+  } else if (TdCallStatus == TDX_EXIT_REASON_OPERAND_INVALID) {
+    Status = EFI_INVALID_PARAMETER;
+  } else {
+    Status = EFI_DEVICE_ERROR;
+  }
+
+  if (Status != EFI_SUCCESS) {
+    DEBUG ((DEBUG_ERROR, "Error returned from TdExtendRtmr call - 0x%lx\n", TdCallStatus));
+  }
+
+  return Status;
+}
diff --git a/MdePkg/Library/TdxLib/TdInfo.c b/MdePkg/Library/TdxLib/TdInfo.c
new file mode 100644
index 000000000000..56c268e70c8d
--- /dev/null
+++ b/MdePkg/Library/TdxLib/TdInfo.c
@@ -0,0 +1,103 @@
+/** @file
+
+  Fetch the Tdx info.
+
+  Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <IndustryStandard/Tdx.h>
+#include <Library/TdxLib.h>
+#include <Library/BaseMemoryLib.h>
+
+UINT64  mTdSharedPageMask = 0;
+UINT32  mTdMaxVCpuNum     = 0;
+UINT32  mTdVCpuNum        = 0;
+
+/**
+  This function gets the Td guest shared page mask.
+
+  The guest indicates if a page is shared using the Guest Physical Address
+  (GPA) Shared (S) bit. If the GPA Width(GPAW) is 48, the S-bit is bit-47.
+  If the GPAW is 52, the S-bit is bit-51.
+
+  @return Shared page bit mask
+**/
+UINT64
+EFIAPI
+TdSharedPageMask (
+  VOID
+  )
+{
+  UINT64                      Status;
+  UINT8                       Gpaw;
+  TD_RETURN_DATA              TdReturnData;
+
+  if (mTdSharedPageMask != 0) {
+    return mTdSharedPageMask;
+  }
+
+  Status = TdCall (TDCALL_TDINFO, 0, 0, 0, &TdReturnData);
+  ASSERT (Status == TDX_EXIT_REASON_SUCCESS);
+
+  Gpaw = (UINT8)(TdReturnData.TdInfo.Gpaw & 0x3f);
+  ASSERT(Gpaw == 48 || Gpaw == 52);
+  mTdSharedPageMask = 1ULL << (Gpaw - 1);
+  return mTdSharedPageMask;
+}
+
+/**
+  This function gets the maximum number of Virtual CPUs that are usable for
+  Td Guest.
+
+  @return maximum Virtual CPUs number
+**/
+UINT32
+EFIAPI
+TdMaxVCpuNum (
+  VOID
+  )
+{
+  UINT64                      Status;
+  TD_RETURN_DATA              TdReturnData;
+
+  if (mTdMaxVCpuNum != 0) {
+    return mTdMaxVCpuNum;
+  }
+
+  Status = TdCall (TDCALL_TDINFO, 0, 0, 0, &TdReturnData);
+  ASSERT (Status == TDX_EXIT_REASON_SUCCESS);
+
+  mTdMaxVCpuNum = TdReturnData.TdInfo.MaxVcpus;
+
+  return mTdMaxVCpuNum;
+}
+
+/**
+  This function gets the number of Virtual CPUs that are usable for Td
+  Guest.
+
+  @return Virtual CPUs number
+**/
+UINT32
+EFIAPI
+TdVCpuNum (
+  VOID
+  )
+{
+  UINT64                      Status;
+  TD_RETURN_DATA              TdReturnData;
+
+  if (mTdVCpuNum != 0) {
+    return mTdVCpuNum;
+  }
+
+  Status = TdCall (TDCALL_TDINFO, 0, 0, 0, &TdReturnData);
+  ASSERT (Status == TDX_EXIT_REASON_SUCCESS);
+
+  mTdVCpuNum = TdReturnData.TdInfo.NumVcpus;
+  return mTdVCpuNum;
+}
diff --git a/MdePkg/Library/TdxLib/TdxLib.inf b/MdePkg/Library/TdxLib/TdxLib.inf
new file mode 100644
index 000000000000..772abcc49d8b
--- /dev/null
+++ b/MdePkg/Library/TdxLib/TdxLib.inf
@@ -0,0 +1,39 @@
+## @file
+# Tdx library
+#
+#  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = TdxLib
+  FILE_GUID                      = 032A8E0D-0C27-40C0-9CAA-23B731C1B223
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = TdxLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources.IA32]
+  TdxLibNull.c
+
+[Sources.X64]
+  AcceptPages.c
+  Rtmr.c
+  TdInfo.c
+  X64/Tdcall.nasm
+  X64/Tdvmcall.nasm
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
diff --git a/MdePkg/Library/TdxLib/TdxLibNull.c b/MdePkg/Library/TdxLib/TdxLibNull.c
new file mode 100644
index 000000000000..d57f03b29cfe
--- /dev/null
+++ b/MdePkg/Library/TdxLib/TdxLibNull.c
@@ -0,0 +1,192 @@
+/** @file
+
+  Null stub of TdxLib
+
+  Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/TdxLib.h>
+
+/**
+  This function accepts a pending private page, and initialize the page to
+  all-0 using the TD ephemeral private key.
+
+  @param[in]  StartAddress     Guest physical address of the private page
+                               to accept.
+  @param[in]  NumberOfPages    Number of the pages to be accepted.
+  @param[in]  PageSize         GPA page size. Accept 1G/2M/4K page size.
+
+  @return EFI_SUCCESS
+**/
+EFI_STATUS
+EFIAPI
+TdAcceptPages (
+  IN UINT64  StartAddress,
+  IN UINT64  NumberOfPages,
+  IN UINT32  PageSize
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  This function extends one of the RTMR measurement register
+  in TDCS with the provided extension data in memory.
+  RTMR extending supports SHA384 which length is 48 bytes.
+
+  @param[in]  Data      Point to the data to be extended
+  @param[in]  DataLen   Length of the data. Must be 48
+  @param[in]  Index     RTMR index
+
+  @return EFI_SUCCESS
+  @return EFI_INVALID_PARAMETER
+  @return EFI_DEVICE_ERROR
+
+**/
+EFI_STATUS
+EFIAPI
+TdExtendRtmr (
+  IN  UINT32  *Data,
+  IN  UINT32  DataLen,
+  IN  UINT8   Index
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+
+/**
+  This function gets the Td guest shared page mask.
+
+  The guest indicates if a page is shared using the Guest Physical Address
+  (GPA) Shared (S) bit. If the GPA Width(GPAW) is 48, the S-bit is bit-47.
+  If the GPAW is 52, the S-bit is bit-51.
+
+  @return Shared page bit mask
+**/
+UINT64
+EFIAPI
+TdSharedPageMask (
+  VOID
+  )
+{
+  return 0;
+}
+
+
+/**
+  This function gets the maximum number of Virtual CPUs that are usable for
+  Td Guest.
+
+  @return maximum Virtual CPUs number
+**/
+UINT32
+EFIAPI
+TdMaxVCpuNum (
+  VOID
+  )
+{
+  return 0;
+}
+
+
+/**
+  This function gets the number of Virtual CPUs that are usable for Td
+  Guest.
+
+  @return Virtual CPUs number
+**/
+UINT32
+EFIAPI
+TdVCpuNum (
+  VOID
+  )
+{
+  return 0;
+}
+
+
+/**
+  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 <https://software.intel.com/content/
+  www/us/en/develop/articles/intel-trust-domain-extensions.html>
+
+  @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
+**/
+EFI_STATUS
+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
+
+**/
+EFI_STATUS
+EFIAPI
+TdVmCall (
+  IN UINT64          Leaf,
+  IN UINT64          Arg1,
+  IN UINT64          Arg2,
+  IN UINT64          Arg3,
+  IN UINT64          Arg4,
+  IN OUT VOID        *Results
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+
+/**
+  This function enable the TD guest to request the VMM to emulate CPUID
+  operation, especially for non-architectural, CPUID leaves.
+
+  @param[in]  Eax        Main leaf of the CPUID
+  @param[in]  Ecx        Sub-leaf of the CPUID
+  @param[out] Results    Returned result of CPUID operation
+
+  @return EFI_SUCCESS
+**/
+EFI_STATUS
+EFIAPI
+TdVmCallCpuid (
+  IN UINT64         Eax,
+  IN UINT64         Ecx,
+  OUT VOID          *Results
+  )
+{
+  return EFI_UNSUPPORTED;
+}
diff --git a/MdePkg/Library/TdxLib/X64/Tdcall.nasm b/MdePkg/Library/TdxLib/X64/Tdcall.nasm
new file mode 100644
index 000000000000..e8a094b0eb3f
--- /dev/null
+++ b/MdePkg/Library/TdxLib/X64/Tdcall.nasm
@@ -0,0 +1,85 @@
+;------------------------------------------------------------------------------
+;*
+;* Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+;* 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/TdxLib/X64/Tdvmcall.nasm b/MdePkg/Library/TdxLib/X64/Tdvmcall.nasm
new file mode 100644
index 000000000000..eb1cb967dc29
--- /dev/null
+++ b/MdePkg/Library/TdxLib/X64/Tdvmcall.nasm
@@ -0,0 +1,207 @@
+;------------------------------------------------------------------------------
+;*
+;* Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+;* SPDX-License-Identifier: BSD-2-Clause-Patent
+;*
+;*
+;------------------------------------------------------------------------------
+
+DEFAULT REL
+SECTION .text
+
+%define TDVMCALL_EXPOSE_REGS_MASK       0xffec
+%define TDVMCALL                        0x0
+%define EXIT_REASON_CPUID               0xa
+
+%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
+
+;------------------------------------------------------------------------------
+; 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
+;  TdVmCallCpuid (
+;    UINT64  EaxIn,    // Rcx
+;    UINT64  EcxIn,    // Rdx
+;    UINT64  *Results  // R8
+;    )
+global ASM_PFX(TdVmCallCpuid)
+ASM_PFX(TdVmCallCpuid):
+       tdcall_push_regs
+
+       mov r11, EXIT_REASON_CPUID
+       mov r12, rcx
+       mov r13, rdx
+
+       ; Save *results pointers
+       push r8
+
+       tdcall_regs_preamble TDVMCALL, TDVMCALL_EXPOSE_REGS_MASK
+
+       tdcall
+
+       ; Panic if TDCALL reports failure.
+       test rax, rax
+       jnz .no_return_data
+
+       ; Propagate TDVMCALL success/failure to return value.
+       mov rax, r10
+       test rax, rax
+       jnz .no_return_data
+
+       ; Retrieve *Results
+       pop r8
+       test r8, r8
+       jz .no_return_data
+       ; Caller pass in buffer so store results r12-r15 contains eax-edx
+       mov [r8 +  0], r12
+       mov [r8 +  8], r13
+       mov [r8 + 16], r14
+       mov [r8 + 24], r15
+
+.no_return_data:
+       tdcall_regs_postamble
+
+       tdcall_pop_regs
+
+       ret
+
+.panic:
+       ud2
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 8b18415b107a..321a14fbaa0a 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -296,6 +296,9 @@
   ##  @libraryclass  Provides services to log the SMI handler registration.
   SmiHandlerProfileLib|Include/Library/SmiHandlerProfileLib.h
 
+  ##  @libraryclass  Provides function to support TDX processing.
+  TdxLib|Include/Library/TdxLib.h
+
 [Guids]
   #
   # GUID defined in UEFI2.1/UEFI2.0/EFI1.1
diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc
index a94959169b2f..d6a7af412be7 100644
--- a/MdePkg/MdePkg.dsc
+++ b/MdePkg/MdePkg.dsc
@@ -175,6 +175,7 @@
   MdePkg/Library/SmiHandlerProfileLibNull/SmiHandlerProfileLibNull.inf
   MdePkg/Library/MmServicesTableLib/MmServicesTableLib.inf
   MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf
+  MdePkg/Library/TdxLib/TdxLib.inf
 
 [Components.EBC]
   MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf
-- 
2.29.2.windows.2