[edk2-devel] [PATCH 04/16] UefiCpuPkg/CcExitLib: Extend the CcExitLib library to support an SVSM

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

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

In order to support an SEV-SNP guest running under an SVSM at VMPL1 or
lower, the CcExitLib library must be extended with new intefaces.

This includes an interface to detect if running under an SVSM, an
interface to return the current VMPL, an interface to perform memory
validation and an interface to set or clear the attribute that allows a
page to be used as a VMSA.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 UefiCpuPkg/Include/Library/CcExitLib.h           | 71 ++++++++++++++++-
 UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c | 82 +++++++++++++++++++-
 2 files changed, 151 insertions(+), 2 deletions(-)

diff --git a/UefiCpuPkg/Include/Library/CcExitLib.h b/UefiCpuPkg/Include/Library/CcExitLib.h
index 3381d583691f..2a9de5d5e8e7 100644
--- a/UefiCpuPkg/Include/Library/CcExitLib.h
+++ b/UefiCpuPkg/Include/Library/CcExitLib.h
@@ -6,7 +6,7 @@
      #VC exceptions.
    - Handle #VE exception in TDX.
 
-  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
 
@@ -147,6 +147,75 @@ CcExitHandleVc (
   IN OUT EFI_SYSTEM_CONTEXT  SystemContext
   );
 
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
 /**
   Handle a #VE exception.
 
diff --git a/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c
index 230e50705b4a..60b19c0433c7 100644
--- a/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c
+++ b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c
@@ -1,7 +1,7 @@
 /** @file
   CcExit Base 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>
   Copyright (c) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -165,6 +165,86 @@ CcExitHandleVc (
   return EFI_UNSUPPORTED;
 }
 
+/**
+  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
+  )
+{
+  return FALSE;
+}
+
+/**
+  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
+  )
+{
+  return 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;
+}
+
 /**
   Handle a #VE exception.
 
-- 
2.42.0



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