1 files changed, 81 insertions, 0 deletions
diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
new file mode 100644
index 0000000000..b6a955ed80
--- /dev/null
+++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
@@ -0,0 +1,81 @@
+/** @file
+  X64 #VC Exception Handler functon.
+
+  Copyright (C) 2020, 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/VmgExitLib.h>
+#include <Register/Amd/Msr.h>
+
+/**
+  Handle a #VC exception.
+
+  Performs the necessary processing to handle a #VC exception.
+
+  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
+                                  as value to use on error.
+  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
+
+  @retval  EFI_SUCCESS            Exception handled
+  @retval  EFI_UNSUPPORTED        #VC not supported, (new) exception value to
+                                  propagate provided
+  @retval  EFI_PROTOCOL_ERROR     #VC handling failed, (new) exception value to
+                                  propagate provided
+
+**/
+EFI_STATUS
+EFIAPI
+VmgExitHandleVc (
+  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
+  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
+  )
+{
+  MSR_SEV_ES_GHCB_REGISTER  Msr;
+  EFI_SYSTEM_CONTEXT_X64    *Regs;
+  GHCB                      *Ghcb;
+  UINT64                    ExitCode, Status;
+  EFI_STATUS                VcRet;
+
+  VcRet = EFI_SUCCESS;
+
+  Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+  ASSERT (Msr.GhcbInfo.Function == 0);
+  ASSERT (Msr.Ghcb != 0);
+
+  Regs = SystemContext.SystemContextX64;
+  Ghcb = Msr.Ghcb;
+
+  VmgInit (Ghcb);
+
+  ExitCode = Regs->ExceptionData;
+  switch (ExitCode) {
+  default:
+    Status = VmgExit (Ghcb, SVM_EXIT_UNSUPPORTED, ExitCode, 0);
+    if (Status == 0) {
+      Regs->ExceptionData = 0;
+      *ExceptionType = GP_EXCEPTION;
+    } else {
+      GHCB_EVENT_INJECTION  Event;
+
+      Event.Uint64 = Status;
+      if (Event.Elements.ErrorCodeValid != 0) {
+        Regs->ExceptionData = Event.Elements.ErrorCode;
+      } else {
+        Regs->ExceptionData = 0;
+      }
+
+      *ExceptionType = Event.Elements.Vector;
+    }
+
+    VcRet = EFI_PROTOCOL_ERROR;
+  }
+
+  VmgDone (Ghcb);
+
+  return VcRet;
+}