[PATCH 2/4] OvmfPkg/IntelTdx: Add TdProbeLib

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

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3902

This is the OvmfPkg specific TdProbeLib. It checks the Ovmf WorkArea
(PcdOvmfWorkAreaBase) to determine if the working system is of Td guest.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c   | 38 ++++++++++++++++++++++
 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf | 25 ++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c
 create mode 100644 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf

diff --git a/OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c b/OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c
new file mode 100644
index 000000000000..85b9c5b614e5
--- /dev/null
+++ b/OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c
@@ -0,0 +1,38 @@
+/** @file
+
+  TdProbeLib is used to probe the Td guest.
+
+  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/TdProbeLib.h>
+#include <WorkArea.h>
+#include <ConfidentialComputingGuestAttr.h>
+
+/**
+  Probe if it is Tdx guest.
+
+  @return TD_PROBE_TDX if it is Tdx guest. Otherwise return TD_PROBE_NON.
+
+**/
+UINTN
+EFIAPI
+TdProbe (
+  VOID
+  )
+{
+  OVMF_WORK_AREA  *WorkArea;
+
+  WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
+
+  //
+  // Check if it is TDX guest.
+  //
+  if ((WorkArea != NULL) && (WorkArea->Header.GuestType == GUEST_TYPE_INTEL_TDX)) {
+    return TD_PROBE_TDX;
+  } else {
+    return TD_PROBE_NON;
+  }
+}
diff --git a/OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf b/OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf
new file mode 100644
index 000000000000..7535008b3a51
--- /dev/null
+++ b/OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf
@@ -0,0 +1,25 @@
+## @file
+# TdProbeLib is used to probe Td guest.
+#
+#  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = TdProbeLib
+  FILE_GUID                      = 05184ec9-abb0-4491-8584-e388639a7c48
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = TdProbeLib
+
+[Sources]
+  TdProbeLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[Pcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase
-- 
2.29.2.windows.2