[PATCH 09/23] UefiCpuPkg: Add VmTdExitLibNull

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

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

VmTdExitLib performs the necessary processing to handle a #VE exception.
VmTdExitLibNull is a NULL instance of VmTdExitLib which provides a default
limited interface. A full feature version of VmTdExitLib should be created
later (for example in OvmfPkg).

PcdTdxIsEnabled indicates if Tdx is enabled.

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: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 UefiCpuPkg/Include/Library/VmTdExitLib.h      | 47 +++++++++++++++++++
 .../Library/VmTdExitLibNull/VmTdExitLibNull.c | 37 +++++++++++++++
 .../VmTdExitLibNull/VmTdExitLibNull.inf       | 34 ++++++++++++++
 UefiCpuPkg/UefiCpuPkg.dec                     |  9 ++++
 UefiCpuPkg/UefiCpuPkg.dsc                     |  2 +
 5 files changed, 129 insertions(+)
 create mode 100644 UefiCpuPkg/Include/Library/VmTdExitLib.h
 create mode 100644 UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.c
 create mode 100644 UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.inf

diff --git a/UefiCpuPkg/Include/Library/VmTdExitLib.h b/UefiCpuPkg/Include/Library/VmTdExitLib.h
new file mode 100644
index 000000000000..a55a76dc7a30
--- /dev/null
+++ b/UefiCpuPkg/Include/Library/VmTdExitLib.h
@@ -0,0 +1,47 @@
+/** @file
+  Public header file for the VMTDEXIT Support library class.
+
+  This library class defines some routines used when invoking the VMEXIT
+  instruction in support of VMX and TDX to handle #VE exceptions.
+
+  Copyright (c) 2020 - 2021, Intel Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef VMTD_EXIT_LIB_H_
+#define VMTD_EXIT_LIB_H_
+
+#include <Library/BaseLib.h>
+#include <Uefi/UefiBaseType.h>
+#include <Protocol/DebugSupport.h>
+
+#define VE_EXCEPTION    20
+
+/**
+  Handle a #VE exception.
+
+  Performs the necessary processing to handle a #VE exception.
+
+  The base library function returns an error equal to VE_EXCEPTION,
+  to be propagated to the standard exception handling stack.
+
+  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
+                                  as value to use on error.
+  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
+
+  @retval  EFI_SUCCESS            Exception handled
+  @retval  EFI_UNSUPPORTED        #VE not supported, (new) exception value to
+                                  propagate provided
+  @retval  EFI_PROTOCOL_ERROR     #VE handling failed, (new) exception value to
+                                  propagate provided
+
+**/
+EFI_STATUS
+EFIAPI
+VmTdExitHandleVe (
+  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
+  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
+  );
+
+#endif
diff --git a/UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.c b/UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.c
new file mode 100644
index 000000000000..a632abfab498
--- /dev/null
+++ b/UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.c
@@ -0,0 +1,37 @@
+/** @file
+
+  Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+#include <Library/BaseLib.h>
+#include <Library/VmTdExitLib.h>
+
+/**
+  Handle a #VE exception.
+
+  Performs the necessary processing to handle a #VE exception.
+
+  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
+                                  as value to use on error.
+  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
+
+  @retval  EFI_SUCCESS            Exception handled
+  @retval  EFI_UNSUPPORTED        #VE not supported, (new) exception value to
+                                  propagate provided
+  @retval  EFI_PROTOCOL_ERROR     #VE handling failed, (new) exception value to
+                                  propagate provided
+
+**/
+EFI_STATUS
+EFIAPI
+VmTdExitHandleVe (
+  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
+  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
+  )
+{
+  *ExceptionType = VE_EXCEPTION;
+
+  return EFI_UNSUPPORTED;
+}
diff --git a/UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.inf b/UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.inf
new file mode 100644
index 000000000000..ae9af1b7f56b
--- /dev/null
+++ b/UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.inf
@@ -0,0 +1,34 @@
+## @file
+#  VMTDEXIT Support Library.
+#
+#  Copyright (c) 2020, Intel Inc. All rights reserved.<BR>
+#  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = VmTdExitLibNull
+  FILE_GUID                      = 79BD5323-6CF4-4ECF-A132-F7D31EEADC1E
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = VmTdExitLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = X64 IA32
+#
+
+[Sources.common]
+  VmTdExitLibNull.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index 62acb291f309..fdc7f9ff48e9 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -62,6 +62,9 @@
   ##  @libraryclass  Provides function for loading microcode.
   MicrocodeLib|Include/Library/MicrocodeLib.h
 
+  ##  @libraryclass  Provides function to support VMTDEXIT processing.
+  VmgExitLib|Include/Library/VmTdExitLib.h
+
 [Guids]
   gUefiCpuPkgTokenSpaceGuid      = { 0xac05bf33, 0x995a, 0x4ed4, { 0xaa, 0xb8, 0xef, 0x7a, 0xe8, 0xf, 0x5c, 0xb0 }}
   gMsegSmramGuid                 = { 0x5802bce4, 0xeeee, 0x4e33, { 0xa1, 0x30, 0xeb, 0xad, 0x27, 0xf0, 0xe4, 0x39 }}
@@ -396,5 +399,11 @@
   # @Prompt SEV-ES Status
   gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|FALSE|BOOLEAN|0x60000016
 
+  ## This dynamic PCD indicates whether Intel TDX is enabled
+  #   TRUE  - Intel TDX is enabled
+  #   FALSE - Intel TDX is not enabled
+  # @Prompt Intel TDX Status
+  gUefiCpuPkgTokenSpaceGuid.PcdTdxIsEnabled|FALSE|BOOLEAN|0x60000017
+
 [UserExtensions.TianoCore."ExtraFiles"]
   UefiCpuPkgExtra.uni
diff --git a/UefiCpuPkg/UefiCpuPkg.dsc b/UefiCpuPkg/UefiCpuPkg.dsc
index 47768b10d5be..a7853f6f6097 100644
--- a/UefiCpuPkg/UefiCpuPkg.dsc
+++ b/UefiCpuPkg/UefiCpuPkg.dsc
@@ -60,6 +60,7 @@
   PeCoffExtraActionLib|MdePkg/Library/BasePeCoffExtraActionLibNull/BasePeCoffExtraActionLibNull.inf
   TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf
   VmgExitLib|UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.inf
+  VmTdExitLib|UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.inf
   MicrocodeLib|UefiCpuPkg/Library/MicrocodeLib/MicrocodeLib.inf
   TdxProbeLib|MdePkg/Library/TdxProbeLib/TdxProbeLib.inf
   TdxLib|MdePkg/Library/TdxLib/TdxLib.inf
@@ -160,6 +161,7 @@
   UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf
   UefiCpuPkg/Library/SmmCpuFeaturesLib/StandaloneMmCpuFeaturesLib.inf
   UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.inf
+  UefiCpuPkg/Library/VmTdExitLibNull/VmTdExitLibNull.inf
   UefiCpuPkg/PiSmmCommunication/PiSmmCommunicationPei.inf
   UefiCpuPkg/PiSmmCommunication/PiSmmCommunicationSmm.inf
   UefiCpuPkg/SecCore/SecCore.inf
-- 
2.29.2.windows.2