[PATCH v2 5/6] OvmfPkg/AmdSev: assign and protect the Sev Secret area

["James Bottomley" <jejb@linux.ibm.com>]

Create a one page secret area in the MEMFD and protect the area with a
boot time HOB.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3077
Signed-off-by: James Bottomley <jejb@linux.ibm.com>
---
 OvmfPkg/AmdSev/AmdSevX64.dsc           |  1 +
 OvmfPkg/AmdSev/AmdSevX64.fdf           |  4 +++
 OvmfPkg/AmdSev/SecretPei/SecretPei.inf | 39 ++++++++++++++++++++++++++
 OvmfPkg/AmdSev/SecretPei/SecretPei.c   | 25 +++++++++++++++++
 4 files changed, 69 insertions(+)
 create mode 100644 OvmfPkg/AmdSev/SecretPei/SecretPei.inf
 create mode 100644 OvmfPkg/AmdSev/SecretPei/SecretPei.c

diff --git a/OvmfPkg/AmdSev/AmdSevX64.dsc b/OvmfPkg/AmdSev/AmdSevX64.dsc
index c0b4e1b274fc..a3f75a626e5e 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.dsc
+++ b/OvmfPkg/AmdSev/AmdSevX64.dsc
@@ -624,6 +624,7 @@ [Components]
     <LibraryClasses>
   }
   UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+  OvmfPkg/AmdSev/SecretPei/SecretPei.inf
 
 !if $(TPM_ENABLE) == TRUE
   OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf
diff --git a/OvmfPkg/AmdSev/AmdSevX64.fdf b/OvmfPkg/AmdSev/AmdSevX64.fdf
index 97f031950abd..c628e6d8f6e7 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.fdf
+++ b/OvmfPkg/AmdSev/AmdSevX64.fdf
@@ -59,6 +59,9 @@ [FD.MEMFD]
 0x00B000|0x001000
 gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase|gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize
 
+0x00C000|0x001000
+gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase|gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize
+
 0x010000|0x010000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize
 
@@ -138,6 +141,7 @@ [FV.PEIFV]
 INF  MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
 INF  UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf
 INF  UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+INF  OvmfPkg/AmdSev/SecretPei/SecretPei.inf
 
 !if $(TPM_ENABLE) == TRUE
 INF  OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf
diff --git a/OvmfPkg/AmdSev/SecretPei/SecretPei.inf b/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
new file mode 100644
index 000000000000..1b40ac036aba
--- /dev/null
+++ b/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
@@ -0,0 +1,39 @@
+## @file
+#  PEI support for SEV Secrets
+#
+#  Copyright (C) 2020 James Bottomley, IBM Corporation.
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = SecretPei
+  FILE_GUID                      = 45260dde-0c3c-4b41-a226-ef3803fac7d4
+  MODULE_TYPE                    = PEIM
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = InitializeSecretPei
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+
+[Sources]
+  SecretPei.c
+
+[Packages]
+  OvmfPkg/OvmfPkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  HobLib
+  PeimEntryPoint
+  PcdLib
+
+[FixedPcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize
+
+[Depex]
+  TRUE
diff --git a/OvmfPkg/AmdSev/SecretPei/SecretPei.c b/OvmfPkg/AmdSev/SecretPei/SecretPei.c
new file mode 100644
index 000000000000..ad491515dd5d
--- /dev/null
+++ b/OvmfPkg/AmdSev/SecretPei/SecretPei.c
@@ -0,0 +1,25 @@
+/** @file
+  SEV Secret boot time HOB placement
+
+  Copyright (C) 2020 James Bottomley, IBM Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+#include <PiPei.h>
+#include <Library/HobLib.h>
+#include <Library/PcdLib.h>
+
+EFI_STATUS
+EFIAPI
+InitializeSecretPei (
+  IN       EFI_PEI_FILE_HANDLE  FileHandle,
+  IN CONST EFI_PEI_SERVICES     **PeiServices
+  )
+{
+  BuildMemoryAllocationHob (
+    PcdGet32 (PcdSevLaunchSecretBase),
+    PcdGet32 (PcdSevLaunchSecretSize),
+    EfiBootServicesData
+    );
+
+  return EFI_SUCCESS;
+}
-- 
2.26.2