From c0e1097656ae0f1f48e0e6538ff448bd1d1fbd90 Mon Sep 17 00:00:00 2001
From: jljusten <jljusten@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Fri, 21 Jan 2011 16:51:00 +0000
Subject: OvmfPkg: Add support for memory above 4GB

When QEMU has more than 3.5GB of RAM, it will map the
additional memory above 4GB.  This change will make that
RAM accessible to OVMF.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11266 6f19259b-4bc3-4df7-8a09-765794883524
---
 OvmfPkg/PlatformPei/MemDetect.c | 45 ++++++++++++++++++++++++++++++++++-------
 OvmfPkg/PlatformPei/Platform.c  | 31 ++++++++++++++++++++++++++++
 OvmfPkg/PlatformPei/Platform.h  | 12 +++++++++++
 3 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/OvmfPkg/PlatformPei/MemDetect.c b/OvmfPkg/PlatformPei/MemDetect.c
index 9a82cc7..78b43d2 100644
--- a/OvmfPkg/PlatformPei/MemDetect.c
+++ b/OvmfPkg/PlatformPei/MemDetect.c
@@ -36,7 +36,7 @@ Module Name:
 
 STATIC
 UINTN
-GetSystemMemorySize (
+GetSystemMemorySizeBelow4gb (
   )
 {
   UINT8 Cmos0x34;
@@ -58,6 +58,31 @@ GetSystemMemorySize (
 }
 
 
+STATIC
+UINT64
+GetSystemMemorySizeAbove4gb (
+  )
+{
+  UINT32 Size;
+  UINTN  CmosIndex;
+
+  //
+  // CMOS 0x5b-0x5d specifies the system memory above 4GB MB.
+  // * CMOS(0x5d) is the most significant size byte
+  // * CMOS(0x5c) is the middle size byte
+  // * CMOS(0x5b) is the least significant size byte
+  // * The size is specified in 64kb chunks
+  //
+
+  Size = 0;
+  for (CmosIndex = 0x5d; CmosIndex >= 0x5b; CmosIndex--) {
+    Size = (UINT32) (Size << 8) + (UINT32) CmosRead8 (CmosIndex);
+  }
+
+  return LShiftU64 (Size, 16);
+}
+
+
 /**
   Peform Memory Detection
 
@@ -71,23 +96,25 @@ MemDetect (
   EFI_STATUS                  Status;
   EFI_PHYSICAL_ADDRESS        MemoryBase;
   UINT64                      MemorySize;
-  UINT64                      TotalMemorySize;
+  UINT64                      LowerMemorySize;
+  UINT64                      UpperMemorySize;
 
   DEBUG ((EFI_D_ERROR, "MemDetect called\n"));
 
   //
   // Determine total memory size available
   //
-  TotalMemorySize = (UINT64)GetSystemMemorySize ();
+  LowerMemorySize = GetSystemMemorySizeBelow4gb ();
+  UpperMemorySize = GetSystemMemorySizeAbove4gb ();
 
   //
   // Determine the range of memory to use during PEI
   //
   MemoryBase = PcdGet32 (PcdOvmfMemFvBase) + PcdGet32 (PcdOvmfMemFvSize);
-  MemorySize = TotalMemorySize - MemoryBase;
-  if (MemorySize > SIZE_16MB) {
-    MemoryBase = TotalMemorySize - SIZE_16MB;
-    MemorySize = SIZE_16MB;
+  MemorySize = LowerMemorySize - MemoryBase;
+  if (MemorySize > SIZE_64MB) {
+    MemoryBase = LowerMemorySize - SIZE_64MB;
+    MemorySize = SIZE_64MB;
   }
 
   //
@@ -103,6 +130,10 @@ MemDetect (
   AddMemoryRangeHob (BASE_1MB, MemoryBase);
   AddMemoryRangeHob (0, BASE_512KB + BASE_128KB);
 
+  if (UpperMemorySize != 0) {
+    AddUntestedMemoryBaseSizeHob (BASE_4GB, UpperMemorySize);
+  }
+
   return MemoryBase + MemorySize;
 }
 
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index 66bb098..fe25486 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -103,6 +103,37 @@ AddMemoryRangeHob (
   AddMemoryBaseSizeHob (MemoryBase, (UINT64)(MemoryLimit - MemoryBase));
 }
 
+
+VOID
+AddUntestedMemoryBaseSizeHob (
+  EFI_PHYSICAL_ADDRESS        MemoryBase,
+  UINT64                      MemorySize
+  )
+{
+  BuildResourceDescriptorHob (
+    EFI_RESOURCE_SYSTEM_MEMORY,
+      EFI_RESOURCE_ATTRIBUTE_PRESENT |
+      EFI_RESOURCE_ATTRIBUTE_INITIALIZED |
+      EFI_RESOURCE_ATTRIBUTE_UNCACHEABLE |
+      EFI_RESOURCE_ATTRIBUTE_WRITE_COMBINEABLE |
+      EFI_RESOURCE_ATTRIBUTE_WRITE_THROUGH_CACHEABLE |
+      EFI_RESOURCE_ATTRIBUTE_WRITE_BACK_CACHEABLE,
+    MemoryBase,
+    MemorySize
+    );
+}
+
+
+VOID
+AddUntestedMemoryRangeHob (
+  EFI_PHYSICAL_ADDRESS        MemoryBase,
+  EFI_PHYSICAL_ADDRESS        MemoryLimit
+  )
+{
+  AddUntestedMemoryBaseSizeHob (MemoryBase, (UINT64)(MemoryLimit - MemoryBase));
+}
+
+
 VOID
 MemMapInitialization (
   EFI_PHYSICAL_ADDRESS  TopOfMemory
diff --git a/OvmfPkg/PlatformPei/Platform.h b/OvmfPkg/PlatformPei/Platform.h
index 0829f89..3e5dca2 100644
--- a/OvmfPkg/PlatformPei/Platform.h
+++ b/OvmfPkg/PlatformPei/Platform.h
@@ -39,6 +39,18 @@ AddMemoryRangeHob (
   EFI_PHYSICAL_ADDRESS        MemoryLimit
   );
 
+VOID
+AddUntestedMemoryBaseSizeHob (
+  EFI_PHYSICAL_ADDRESS        MemoryBase,
+  UINT64                      MemorySize
+  );
+
+VOID
+AddUntestedMemoryRangeHob (
+  EFI_PHYSICAL_ADDRESS        MemoryBase,
+  EFI_PHYSICAL_ADDRESS        MemoryLimit
+  );
+
 EFI_PHYSICAL_ADDRESS
 MemDetect (
   VOID
-- 
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