[edk2-devel] [RFC PATCH 09/28] UefiCpuPkg/CpuExceptionHandler: Add base support for the #VC exception

[Lendacky, Thomas]

From: Tom Lendacky <thomas.lendacky at amd.com>

Add base support to handle #VC exceptions.  This includes a stub routine
to invoke when a #VC exception occurs and special checks in the common
exception handlers to invoke the #VC exception handler routine.

Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
---
 .../DxeCpuExceptionHandlerLib.inf                |  2 ++
 .../PeiCpuExceptionHandlerLib.inf                |  2 ++
 .../SecPeiCpuExceptionHandlerLib.inf             |  2 ++
 .../CpuExceptionHandlerLib/AMDSevVcCommon.h      | 12 ++++++++++++
 .../CpuExceptionHandlerLib/CpuExceptionCommon.h  |  2 ++
 .../CpuExceptionHandlerLib/CpuExceptionCommon.c  |  2 +-
 .../PeiDxeAMDSevVcHandler.c                      | 11 +++++++++++
 .../PeiDxeSmmCpuException.c                      | 16 ++++++++++++++++
 .../CpuExceptionHandlerLib/SecAMDSevVcHandler.c  | 11 +++++++++++
 .../CpuExceptionHandlerLib/SecPeiCpuException.c  | 16 ++++++++++++++++
 10 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 UefiCpuPkg/Library/CpuExceptionHandlerLib/AMDSevVcCommon.h
 create mode 100644 UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeAMDSevVcHandler.c
 create mode 100644 UefiCpuPkg/Library/CpuExceptionHandlerLib/SecAMDSevVcHandler.c

diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf
index e41383573043..331ae7334c45 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf
@@ -37,6 +37,8 @@ [Sources.common]
   CpuExceptionCommon.c
   PeiDxeSmmCpuException.c
   DxeException.c
+  PeiDxeAMDSevVcHandler.c
+  AMDSevVcCommon.h
 
 [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
index f31423ac0f91..89b5d496e56f 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
@@ -37,6 +37,8 @@ [Sources.common]
   CpuExceptionCommon.c
   PeiCpuException.c
   PeiDxeSmmCpuException.c
+  PeiDxeAMDSevVcHandler.c
+  AMDSevVcCommon.h
 
 [Packages]
   MdePkg/MdePkg.dec
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
index 6d25cafe2ca3..5e5ab6244b11 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
@@ -36,6 +36,8 @@ [Sources.common]
   CpuExceptionCommon.h
   CpuExceptionCommon.c
   SecPeiCpuException.c
+  SecAMDSevVcHandler.c
+  AMDSevVcCommon.h
 
 [Packages]
   MdePkg/MdePkg.dec
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/AMDSevVcCommon.h b/UefiCpuPkg/Library/CpuExceptionHandlerLib/AMDSevVcCommon.h
new file mode 100644
index 000000000000..ee52f3b5220d
--- /dev/null
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/AMDSevVcCommon.h
@@ -0,0 +1,12 @@
+
+#ifndef _AMD_SEV_VC_COMMON_H_
+#define _AMD_SEV_VC_COMMON_H_
+
+#include <Protocol/DebugSupport.h>
+
+UINTN
+DoVcException(
+  EFI_SYSTEM_CONTEXT  Context
+  );
+
+#endif
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h
index 805dd9cbb4ff..0f274e7ea328 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h
@@ -24,6 +24,8 @@
 #define  CPU_INTERRUPT_NUM         256
 #define  HOOKAFTER_STUB_SIZE        16
 
+#define  VC_EXCEPTION               29
+
 //
 // Exception Error Code of Page-Fault Exception
 //
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c
index 8adbd43fefb4..39e4dd9e9417 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.c
@@ -14,7 +14,7 @@
 //
 // 1 means an error code will be pushed, otherwise 0
 //
-CONST UINT32 mErrorCodeFlag = 0x00227d00;
+CONST UINT32 mErrorCodeFlag = 0x20227d00;
 
 //
 // Define the maximum message length
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeAMDSevVcHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeAMDSevVcHandler.c
new file mode 100644
index 000000000000..1e027b3f2964
--- /dev/null
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeAMDSevVcHandler.c
@@ -0,0 +1,11 @@
+
+#include "CpuExceptionCommon.h"
+#include "AMDSevVcCommon.h"
+
+UINTN
+DoVcException(
+  EFI_SYSTEM_CONTEXT  Context
+  )
+{
+  return 0;
+}
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
index 72c2aeca4c13..0c248e7eb904 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
@@ -7,6 +7,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 **/
 
 #include "CpuExceptionCommon.h"
+#include "AMDSevVcCommon.h"
 #include <Library/DebugLib.h>
 
 /**
@@ -86,6 +87,21 @@ CommonExceptionHandlerWorker (
     break;
   }
 
+  if (ExceptionType == VC_EXCEPTION) {
+    UINTN  Status;
+    //
+    // #VC must be handled for an SEV-ES guest
+    //
+    Status = DoVcException(SystemContext);
+    if (Status) {
+      // Exception not handled - Status contains the desired exception now
+      ExceptionType = Status;
+    } else {
+      // Exception handled
+      return;
+    }
+  }
+
   if (ExternalInterruptHandler != NULL &&
       ExternalInterruptHandler[ExceptionType] != NULL) {
     (ExternalInterruptHandler[ExceptionType]) (ExceptionType, SystemContext);
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecAMDSevVcHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecAMDSevVcHandler.c
new file mode 100644
index 000000000000..1e027b3f2964
--- /dev/null
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecAMDSevVcHandler.c
@@ -0,0 +1,11 @@
+
+#include "CpuExceptionCommon.h"
+#include "AMDSevVcCommon.h"
+
+UINTN
+DoVcException(
+  EFI_SYSTEM_CONTEXT  Context
+  )
+{
+  return 0;
+}
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
index 20148db74cf8..998a90ba61a6 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
@@ -8,6 +8,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 #include <PiPei.h>
 #include "CpuExceptionCommon.h"
+#include "AMDSevVcCommon.h"
 
 CONST UINTN    mDoFarReturnFlag  = 0;
 
@@ -24,6 +25,21 @@ CommonExceptionHandler (
   IN EFI_SYSTEM_CONTEXT   SystemContext
   )
 {
+  if (ExceptionType == VC_EXCEPTION) {
+    UINTN  Status;
+    //
+    // #VC must be handled for an SEV-ES guest
+    //
+    Status = DoVcException(SystemContext);
+    if (Status) {
+      // Exception not handled - Status contains the desired exception now
+      ExceptionType = Status;
+    } else {
+      // Exception handled
+      return;
+    }
+  }
+
   //
   // Initialize the serial port before dumping.
   //
-- 
2.17.1


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