[PATCH v3 3/3] OvmfPkg/PlatformPei: Mark SEC GHCB page in the page encrpytion bitmap.

["Ashish Kalra" <ashish.kalra@amd.com>]

From: Ashish Kalra <ashish.kalra@amd.com>

Mark the SEC GHCB page that is mapped as unencrypted in
ResetVector code in the hypervisor page encryption bitmap.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 OvmfPkg/PlatformPei/AmdSev.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
index 4a515a4847..da9470db7f 100644
--- a/OvmfPkg/PlatformPei/AmdSev.c
+++ b/OvmfPkg/PlatformPei/AmdSev.c
@@ -15,6 +15,7 @@
 #include <Library/HobLib.h>
 #include <Library/MemEncryptSevLib.h>
 #include <Library/MemoryAllocationLib.h>
+#include <Library/MemEncryptHypercallLib.h>
 #include <Library/PcdLib.h>
 #include <PiPei.h>
 #include <Register/Amd/Cpuid.h>
@@ -49,6 +50,15 @@ AmdSevEsInitialize (
   PcdStatus = PcdSetBoolS (PcdSevEsIsEnabled, TRUE);
   ASSERT_RETURN_ERROR (PcdStatus);
 
+  //
+  // GHCB_BASE setup during reset-vector needs to be marked as
+  // decrypted in the hypervisor page encryption bitmap.
+  //
+  SetMemoryEncDecHypercall3 (FixedPcdGet32 (PcdOvmfSecGhcbBase),
+    EFI_SIZE_TO_PAGES(FixedPcdGet32 (PcdOvmfSecGhcbSize)),
+    FALSE
+    );
+
   //
   // Allocate GHCB and per-CPU variable pages.
   //   Since the pages must survive across the UEFI to OS transition
-- 
2.17.1