diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
index 6dea6e771a..169c04b9ce 100644
--- a/OvmfPkg/Sec/SecMain.c
+++ b/OvmfPkg/Sec/SecMain.c
@@ -24,6 +24,9 @@
 #include <Library/PeCoffExtraActionLib.h>
 #include <Library/ExtractGuidedSectionLib.h>
 #include <Library/LocalApicLib.h>
+#include <Library/CpuExceptionHandlerLib.h>
+#include <Register/Amd/Ghcb.h>
+#include <Register/Amd/Msr.h>
 
 #include <Ppi/TemporaryRamSupport.h>
 
@@ -34,6 +37,10 @@ typedef struct _SEC_IDT_TABLE {
   IA32_IDT_GATE_DESCRIPTOR  IdtTable[SEC_IDT_ENTRY_COUNT];
 } SEC_IDT_TABLE;
 
+typedef struct _SEC_SEV_ES_WORK_AREA {
+  UINT8  SevEsEnabled;
+} SEC_SEV_ES_WORK_AREA;
+
 VOID
 EFIAPI
 SecStartupPhase2 (
@@ -712,6 +719,120 @@ FindAndReportEntryPoints (
   return;
 }
 
+/**
+  Handle an SEV-ES/GHCB protocol check failure.
+
+  Notify the hypervisor using the VMGEXIT instruction that the SEV-ES guest
+  wishes to be terminated.
+
+  @param[in] ReasonCode  Reason code to provide to the hypervisor for the
+                         termination request.
+
+**/
+STATIC
+VOID
+SevEsProtocolFailure (
+  IN UINT8  ReasonCode
+  )
+{
+  MSR_SEV_ES_GHCB_REGISTER  Msr;
+
+  //
+  // Use the GHCB MSR Protocol to request termination by the hypervisor
+  //
+  Msr.GhcbPhysicalAddress = 0;
+  Msr.GhcbTerminate.Function = GHCB_INFO_TERMINATE_REQUEST;
+  Msr.GhcbTerminate.ReasonCodeSet = GHCB_TERMINATE_GHCB;
+  Msr.GhcbTerminate.ReasonCode = ReasonCode;
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+  AsmVmgExit ();
+
+  ASSERT (FALSE);
+  CpuDeadLoop ();
+}
+
+/**
+  Validate the SEV-ES/GHCB protocol level.
+
+  Verify that the level of SEV-ES/GHCB protocol supported by the hypervisor
+  and the guest intersect. If they don't intersect, request termination.
+
+**/
+STATIC
+VOID
+SevEsProtocolCheck (
+  VOID
+  )
+{
+  MSR_SEV_ES_GHCB_REGISTER  Msr;
+  GHCB                      *Ghcb;
+
+  //
+  // Use the GHCB MSR Protocol to obtain the GHCB SEV-ES Information for
+  // protocol checking
+  //
+  Msr.GhcbPhysicalAddress = 0;
+  Msr.GhcbInfo.Function = GHCB_INFO_SEV_INFO_GET;
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+  AsmVmgExit ();
+
+  Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+  if (Msr.GhcbInfo.Function != GHCB_INFO_SEV_INFO) {
+    SevEsProtocolFailure (GHCB_TERMINATE_GHCB_GENERAL);
+  }
+
+  if (Msr.GhcbProtocol.SevEsProtocolMin > Msr.GhcbProtocol.SevEsProtocolMax) {
+    SevEsProtocolFailure (GHCB_TERMINATE_GHCB_PROTOCOL);
+  }
+
+  if ((Msr.GhcbProtocol.SevEsProtocolMin > GHCB_VERSION_MAX) ||
+      (Msr.GhcbProtocol.SevEsProtocolMax < GHCB_VERSION_MIN)) {
+    SevEsProtocolFailure (GHCB_TERMINATE_GHCB_PROTOCOL);
+  }
+
+  //
+  // SEV-ES protocol checking succeeded, set the initial GHCB address
+  //
+  Msr.GhcbPhysicalAddress = FixedPcdGet32 (PcdOvmfSecGhcbBase);
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+  Ghcb = Msr.Ghcb;
+  SetMem (Ghcb, sizeof (*Ghcb), 0);
+
+  //
+  // Set the version to the maximum that can be supported
+  //
+  Ghcb->ProtocolVersion = MIN (Msr.GhcbProtocol.SevEsProtocolMax, GHCB_VERSION_MAX);
+  Ghcb->GhcbUsage = GHCB_STANDARD_USAGE;
+}
+
+/**
+  Determine if SEV-ES is active.
+
+  During early booting, SEV-ES support code will set a flag to indicate that
+  SEV-ES is enabled. Return the value of this flag as an indicator that SEV-ES
+  is enabled.
+
+  @retval TRUE   SEV-ES is enabled
+  @retval FALSE  SEV-ES is not enabled
+
+**/
+STATIC
+BOOLEAN
+SevEsIsEnabled (
+  VOID
+  )
+{
+  SEC_SEV_ES_WORK_AREA  *SevEsWorkArea;
+
+  SevEsWorkArea = (SEC_SEV_ES_WORK_AREA *) FixedPcdGet32 (PcdSevEsWorkAreaBase);
+
+  return ((SevEsWorkArea != NULL) && (SevEsWorkArea->SevEsEnabled != 0));
+}
+
 VOID
 EFIAPI
 SecCoreStartupWithStack (
@@ -737,8 +858,56 @@ SecCoreStartupWithStack (
     Table[Index] = 0;
   }
 
+  //
+  // Initialize IDT - Since this is before library constructors are called,
+  // we use a loop rather than CopyMem.
+  //
+  IdtTableInStack.PeiService = NULL;
+  for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index ++) {
+    UINT8  *Src;
+    UINT8  *Dst;
+    UINTN  Byte;
+
+    Src = (UINT8 *) &mIdtEntryTemplate;
+    Dst = (UINT8 *) &IdtTableInStack.IdtTable[Index];
+    for (Byte = 0; Byte < sizeof (mIdtEntryTemplate); Byte++) {
+      Dst[Byte] = Src[Byte];
+    }
+  }
+
+  IdtDescriptor.Base  = (UINTN)&IdtTableInStack.IdtTable;
+  IdtDescriptor.Limit = (UINT16)(sizeof (IdtTableInStack.IdtTable) - 1);
+
+  if (SevEsIsEnabled ()) {
+    SevEsProtocolCheck ();
+
+    //
+    // For SEV-ES guests, the exception handler is needed before calling
+    // ProcessLibraryConstructorList() because some of the library constructors
+    // perform some functions that result in #VC exceptions being generated.
+    //
+    // Due to this code executing before library constructors, *all* library
+    // API calls are theoretically interface contract violations. However,
+    // because this is SEC (executing in flash), those constructors cannot
+    // write variables with static storage duration anyway. Furthermore, only
+    // a small, restricted set of APIs, such as AsmWriteIdtr() and
+    // InitializeCpuExceptionHandlers(), are called, where we require that the
+    // underlying library not require constructors to have been invoked and
+    // that the library instance not trigger any #VC exceptions.
+    //
+    AsmWriteIdtr (&IdtDescriptor);
+    InitializeCpuExceptionHandlers (NULL);
+  }
+
   ProcessLibraryConstructorList (NULL, NULL);
 
+  if (!SevEsIsEnabled ()) {
+    //
+    // For non SEV-ES guests, just load the IDTR.
+    //
+    AsmWriteIdtr (&IdtDescriptor);
+  }
+
   DEBUG ((DEBUG_INFO,
     "SecCoreStartupWithStack(0x%x, 0x%x)\n",
     (UINT32)(UINTN)BootFv,
@@ -751,19 +920,6 @@ SecCoreStartupWithStack (
   //
   InitializeFloatingPointUnits ();
 
-  //
-  // Initialize IDT
-  //
-  IdtTableInStack.PeiService = NULL;
-  for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index ++) {
-    CopyMem (&IdtTableInStack.IdtTable[Index], &mIdtEntryTemplate, sizeof (mIdtEntryTemplate));
-  }
-
-  IdtDescriptor.Base  = (UINTN)&IdtTableInStack.IdtTable;
-  IdtDescriptor.Limit = (UINT16)(sizeof (IdtTableInStack.IdtTable) - 1);
-
-  AsmWriteIdtr (&IdtDescriptor);
-
 #if defined (MDE_CPU_X64)
   //
   // ASSERT that the Page Tables were set by the reset vector code to
diff --git a/OvmfPkg/Sec/SecMain.inf b/OvmfPkg/Sec/SecMain.inf
index 63ba4cb555..7f78dcee27 100644
--- a/OvmfPkg/Sec/SecMain.inf
+++ b/OvmfPkg/Sec/SecMain.inf
@@ -50,15 +50,19 @@
   PeCoffExtraActionLib
   ExtractGuidedSectionLib
   LocalApicLib
+  CpuExceptionHandlerLib
 
 [Ppis]
   gEfiTemporaryRamSupportPpiGuid                # PPI ALWAYS_PRODUCED
 
 [Pcd]
+  gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvSize
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvSize
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbSize
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize