[PATCH V3 2/9] OvmfPkg/IntelTdx: Add TdxHelperLibNull

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

From: Min M Xu <min.m.xu@intel.com>

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4243

TdxHelperLib provides below helper functions for a td-guest.
 - TdxHelperProcessTdHob
 - TdxHelperMeasureTdHob
 - TdxHelperMeasureCfvImage
 - TdxHelperBuildGuidHobForTdxMeasurement

TdxHelperLibNull is the NULL instance of TdxHelperLib.

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 OvmfPkg/Include/Library/TdxHelperLib.h        | 70 ++++++++++++++++
 .../TdxHelperLib/TdxHelperLibNull.inf         | 32 ++++++++
 OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperNull.c | 79 +++++++++++++++++++
 OvmfPkg/OvmfPkg.dec                           |  4 +
 4 files changed, 185 insertions(+)
 create mode 100644 OvmfPkg/Include/Library/TdxHelperLib.h
 create mode 100644 OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperLibNull.inf
 create mode 100644 OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperNull.c

diff --git a/OvmfPkg/Include/Library/TdxHelperLib.h b/OvmfPkg/Include/Library/TdxHelperLib.h
new file mode 100644
index 000000000000..199aade42f8e
--- /dev/null
+++ b/OvmfPkg/Include/Library/TdxHelperLib.h
@@ -0,0 +1,70 @@
+/** @file
+  TdxHelperLib header file
+
+  Copyright (c) 2021 - 2023, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef TDX_HELPER_LIB_H
+#define TDX_HELPER_LIB_H
+
+#include <PiPei.h>
+
+/**
+  In Tdx guest, some information need to be passed from host VMM to guest
+  firmware. For example, the memory resource, etc. These information are
+  prepared by host VMM and put in TdHob which is described in TdxMetadata.
+  TDVF processes the TdHob to accept memories.
+
+  @retval   EFI_SUCCESS   Successfully process the TdHob
+  @retval   Others        Other error as indicated
+**/
+EFI_STATUS
+EFIAPI
+TdxHelperProcessTdHob (
+  VOID
+  );
+
+/**
+  In Tdx guest, TdHob is passed from host VMM to guest firmware and it contains
+  the information of the memory resource. From the security perspective before
+  it is consumed, it should be measured and extended.
+ *
+ * @retval EFI_SUCCESS Successfully measure the TdHob
+ * @retval Others      Other error as indicated
+ */
+EFI_STATUS
+EFIAPI
+TdxHelperMeasureTdHob (
+  VOID
+  );
+
+/**
+ * In Tdx guest, Configuration FV (CFV) is treated as external input because it
+ * may contain the data provided by VMM. From the sucurity perspective Cfv image
+ * should be measured before it is consumed.
+ *
+ * @retval EFI_SUCCESS Successfully measure the CFV image
+ * @retval Others      Other error as indicated
+ */
+EFI_STATUS
+EFIAPI
+TdxHelperMeasureCfvImage (
+  VOID
+  );
+
+/**
+  Build the GuidHob for tdx measurements which were done in SEC phase.
+  The measurement values are stored in WorkArea.
+
+  @retval EFI_SUCCESS  The GuidHob is built successfully
+  @retval Others       Other errors as indicated
+**/
+EFI_STATUS
+EFIAPI
+TdxHelperBuildGuidHobForTdxMeasurement (
+  VOID
+  );
+
+#endif
diff --git a/OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperLibNull.inf b/OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperLibNull.inf
new file mode 100644
index 000000000000..27d07b3886cf
--- /dev/null
+++ b/OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperLibNull.inf
@@ -0,0 +1,32 @@
+## @file
+#  TdxHelperLib NULL instance
+#
+#  Copyright (c) 2021 - 2023, Intel Corporation. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = TdxHelperLibNull
+  FILE_GUID                      = 853603b2-53ea-463d-93e6-35d09a79e358
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = TdxHelperLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = X64
+#
+
+[Sources]
+  TdxHelperNull.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseLib
diff --git a/OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperNull.c b/OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperNull.c
new file mode 100644
index 000000000000..a2125190d6aa
--- /dev/null
+++ b/OvmfPkg/IntelTdx/TdxHelperLib/TdxHelperNull.c
@@ -0,0 +1,79 @@
+/** @file
+  NULL instance of TdxHelperLib
+
+  Copyright (c) 2022 - 2023, Intel Corporation. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <PiPei.h>
+
+/**
+  In Tdx guest, some information need to be passed from host VMM to guest
+  firmware. For example, the memory resource, etc. These information are
+  prepared by host VMM and put in TdHob which is described in TdxMetadata.
+  TDVF processes the TdHob to accept memories.
+
+  @retval   EFI_SUCCESS   Successfully process the TdHob
+  @retval   Others        Other error as indicated
+**/
+EFI_STATUS
+EFIAPI
+TdxHelperProcessTdHob (
+  VOID
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  In Tdx guest, TdHob is passed from host VMM to guest firmware and it contains
+  the information of the memory resource. From the security perspective before
+  it is consumed, it should be measured and extended.
+ *
+ * @retval EFI_SUCCESS Successfully measure the TdHob
+ * @retval Others      Other error as indicated
+ */
+EFI_STATUS
+EFIAPI
+TdxHelperMeasureTdHob (
+  VOID
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+ * In Tdx guest, Configuration FV (CFV) is treated as external input because it
+ * may contain the data provided by VMM. From the sucurity perspective Cfv image
+ * should be measured before it is consumed.
+ *
+ * @retval EFI_SUCCESS Successfully measure the CFV image
+ * @retval Others      Other error as indicated
+ */
+EFI_STATUS
+EFIAPI
+TdxHelperMeasureCfvImage (
+  VOID
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Build the GuidHob for tdx measurements which were done in SEC phase.
+  The measurement values are stored in WorkArea.
+
+  @retval EFI_SUCCESS  The GuidHob is built successfully
+  @retval Others       Other errors as indicated
+**/
+EFI_STATUS
+EFIAPI
+TdxHelperBuildGuidHobForTdxMeasurement (
+  VOID
+  )
+{
+  return EFI_UNSUPPORTED;
+}
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 1b521f2604ff..f30225d7656d 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -98,6 +98,10 @@
   #
   SerializeVariablesLib|Include/Library/SerializeVariablesLib.h
 
+  ##  @libraryclass  TdxHelper
+  #
+  TdxHelperLib|Include/Library/TdxHelperLib.h
+
   ##  @libraryclass  Declares utility functions for virtio device drivers.
   VirtioLib|Include/Library/VirtioLib.h
 
-- 
2.29.2.windows.2