From a781f7099bc2584fd065f1947bedd49adfea0fa5 Mon Sep 17 00:00:00 2001
From: Jordan Justen <jordan.l.justen@intel.com>
Date: Tue, 4 Mar 2014 08:02:37 +0000
Subject: [PATCH] OvmfPkg/Sec: Don't decompress the FV on S3 resume

Since we marked the FV at PcdOvmfPeiMemFvBase as ACPI NVS memory,
we can use it on S3 resume.

The FV at PcdOvmfDxeMemFvBase may have been overwritten by the OS,
but we do not use it's contents on S3 resume.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15296 6f19259b-4bc3-4df7-8a09-765794883524
---
 OvmfPkg/Sec/SecMain.c | 54 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
index 0edc4f9af3..670ad8d763 100644
--- a/OvmfPkg/Sec/SecMain.c
+++ b/OvmfPkg/Sec/SecMain.c
@@ -469,6 +469,50 @@ FindPeiCoreImageBaseInFv (
   return EFI_SUCCESS;
 }
 
+
+/**
+  Reads 8-bits of CMOS data.
+
+  Reads the 8-bits of CMOS data at the location specified by Index.
+  The 8-bit read value is returned.
+
+  @param  Index  The CMOS location to read.
+
+  @return The value read.
+
+**/
+STATIC
+UINT8
+CmosRead8 (
+  IN      UINTN                     Index
+  )
+{
+  IoWrite8 (0x70, (UINT8) Index);
+  return IoRead8 (0x71);
+}
+
+
+STATIC
+BOOLEAN
+IsS3Resume (
+  VOID
+  )
+{
+  return (CmosRead8 (0xF) == 0xFE);
+}
+
+
+STATIC
+EFI_STATUS
+GetS3ResumePeiFv (
+  IN OUT EFI_FIRMWARE_VOLUME_HEADER       **PeiFv
+  )
+{
+  *PeiFv = (EFI_FIRMWARE_VOLUME_HEADER*)(UINTN) PcdGet32 (PcdOvmfPeiMemFvBase);
+  return EFI_SUCCESS;
+}
+
+
 /**
   Locates the PEI Core entry point address
 
@@ -488,9 +532,15 @@ FindPeiCoreImageBase (
 {
   *PeiCoreImageBase = 0;
 
-  FindMainFv (BootFv);
+  if (IsS3Resume ()) {
+    DEBUG ((EFI_D_VERBOSE, "SEC: S3 resume\n"));
+    GetS3ResumePeiFv (BootFv);
+  } else {
+    DEBUG ((EFI_D_VERBOSE, "SEC: Normal boot\n"));
+    FindMainFv (BootFv);
 
-  DecompressMemFvs (BootFv);
+    DecompressMemFvs (BootFv);
+  }
 
   FindPeiCoreImageBaseInFv (*BootFv, PeiCoreImageBase);
 }
-- 
2.39.2