[edk2-devel] [PATCH 05/16] Ovmfpkg/CcExitLib: Extend CcExitLib to handle SVSM related services

["Lendacky, Thomas via groups.io" <thomas.lendacky=amd.com@groups.io>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

Add initial support for the new CcExitLib interfaces to the OvmfPkg
version of the library. The initial implementation will fully implement
the SVSM presence check API and the SVSM VMPL API, with later patches
fully implementing the other interfaces.

The SVSM presence check, CcExitSnpSvsmPresent(), determines the presence
of an SVSM by checking if an SVSM has been advertised in the SEV-SNP
Secrets Page. The SVSM VMPL API, CcExitSnpGetVmpl(), returns the VMPL
level at which the OVMF is currently running.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 OvmfPkg/Library/CcExitLib/CcExitLib.inf    |   5 +-
 OvmfPkg/Library/CcExitLib/SecCcExitLib.inf |   5 +-
 OvmfPkg/Library/CcExitLib/CcExitSvsm.c     | 102 ++++++++++++++++++++
 3 files changed, 110 insertions(+), 2 deletions(-)

diff --git a/OvmfPkg/Library/CcExitLib/CcExitLib.inf b/OvmfPkg/Library/CcExitLib/CcExitLib.inf
index bc75cd5f5a04..2e68b12bb4e2 100644
--- a/OvmfPkg/Library/CcExitLib/CcExitLib.inf
+++ b/OvmfPkg/Library/CcExitLib/CcExitLib.inf
@@ -1,7 +1,7 @@
 ## @file
 #  CcExitLib Library.
 #
-#  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+#  Copyright (C) 2020 - 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
 #  Copyright (C) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -23,6 +23,7 @@ [Defines]
 
 [Sources.common]
   CcExitLib.c
+  CcExitSvsm.c
   CcExitVcHandler.c
   CcExitVcHandler.h
   CcInstruction.c
@@ -45,3 +46,5 @@ [LibraryClasses]
 [Pcd]
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidSize
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsSize
diff --git a/OvmfPkg/Library/CcExitLib/SecCcExitLib.inf b/OvmfPkg/Library/CcExitLib/SecCcExitLib.inf
index 811269dd2c06..7b81900a11d4 100644
--- a/OvmfPkg/Library/CcExitLib/SecCcExitLib.inf
+++ b/OvmfPkg/Library/CcExitLib/SecCcExitLib.inf
@@ -1,7 +1,7 @@
 ## @file
 #  VMGEXIT Support Library.
 #
-#  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+#  Copyright (C) 2020 - 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
 ##
@@ -22,6 +22,7 @@ [Defines]
 
 [Sources.common]
   CcExitLib.c
+  CcExitSvsm.c
   CcExitVcHandler.c
   CcExitVcHandler.h
   CcInstruction.c
@@ -45,5 +46,7 @@ [LibraryClasses]
 [FixedPcd]
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupSize
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsSize
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidSize
diff --git a/OvmfPkg/Library/CcExitLib/CcExitSvsm.c b/OvmfPkg/Library/CcExitLib/CcExitSvsm.c
new file mode 100644
index 000000000000..fb8b762caadc
--- /dev/null
+++ b/OvmfPkg/Library/CcExitLib/CcExitSvsm.c
@@ -0,0 +1,102 @@
+/** @file
+  SVSM Support Library.
+
+  Copyright (C) 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <Uefi.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/CcExitLib.h>
+#include <Register/Amd/Msr.h>
+#include <Register/Amd/Svsm.h>
+
+/**
+  Report the presence of an Secure Virtual Services Module (SVSM).
+
+  Determines the presence of an SVSM.
+
+  @retval  TRUE                   An SVSM is present
+  @retval  FALSE                  An SVSM is not present
+
+**/
+BOOLEAN
+EFIAPI
+CcExitSnpSvsmPresent (
+  VOID
+  )
+{
+  SVSM_INFORMATION  *SvsmInfo;
+
+  SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+  return (SvsmInfo != NULL && SvsmInfo->SvsmSize != 0);
+}
+
+/**
+  Report the VMPL level at which the SEV-SNP guest is running.
+
+  Determines the VMPL level at which the guest is running. If an SVSM is
+  not present, then it must be VMPL0, otherwise return what is reported
+  by the SVSM.
+
+  @return                         The VMPL level
+
+**/
+UINT8
+EFIAPI
+CcExitSnpGetVmpl (
+  VOID
+  )
+{
+  SVSM_INFORMATION  *SvsmInfo;
+
+  SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+  return CcExitSnpSvsmPresent () ? SvsmInfo->SvsmGuestVmpl : 0;
+}
+
+/**
+  Perform a PVALIDATE operation for the page ranges specified.
+
+  Validate or rescind the validation of the specified pages.
+
+  @param[in]       Info           Pointer to a page state change structure
+
+**/
+VOID
+EFIAPI
+CcExitSnpPvalidate (
+  IN SNP_PAGE_STATE_CHANGE_INFO  *Info
+  )
+{
+}
+
+/**
+  Perform an RMPADJUST operation to alter the VMSA setting of a page.
+
+  Add or remove the VMSA attribute for a page.
+
+  @param[in]       Vmsa           Pointer to an SEV-ES save area page
+  @param[in]       ApicId         APIC ID associated with the VMSA
+  @param[in]       SetVmsa        Boolean indicator as to whether to set or
+                                  or clear the VMSA setting for the page
+
+  @retval  EFI_SUCCESS            RMPADJUST operation successful
+  @retval  EFI_UNSUPPORTED        Operation is not supported
+  @retval  EFI_INVALID_PARAMETER  RMPADJUST operation failed, an invalid
+                                  parameter was supplied
+
+**/
+EFI_STATUS
+EFIAPI
+CcExitSnpVmsaRmpAdjust (
+  IN SEV_ES_SAVE_AREA  *Vmsa,
+  IN UINT32            ApicId,
+  IN BOOLEAN           SetVmsa
+  )
+{
+  return EFI_UNSUPPORTED;
+}
-- 
2.42.0



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