[PATCH 2/2] UefiCpuPkg/CpuDxe: Fix out-of-sync issue in page

[Jian J Wang <jian.j.wang@intel.com>]

>From CpuDxe driver perspective, it doesn't update GCD memory attributes 
from current page table setup during its initialization. So the memory
attributes in GCD might not reflect all memory attributes in real world.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Suggested-by: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 UefiCpuPkg/CpuDxe/CpuDxe.c       |  5 +++
 UefiCpuPkg/CpuDxe/CpuDxe.h       |  9 ++++
 UefiCpuPkg/CpuDxe/CpuPageTable.c | 92 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+)

diff --git a/UefiCpuPkg/CpuDxe/CpuDxe.c b/UefiCpuPkg/CpuDxe/CpuDxe.c
index b386f3b677..4e8fa100e0 100644
--- a/UefiCpuPkg/CpuDxe/CpuDxe.c
+++ b/UefiCpuPkg/CpuDxe/CpuDxe.c
@@ -863,6 +863,11 @@ RefreshGcdMemoryAttributes (
     FreePool (MemorySpaceMap);
   }
 
+  //
+  // Update page attributes
+  //
+  RefreshGcdMemoryAttributesFromPaging();
+
   mIsFlushingGCD = FALSE;
 }
 
diff --git a/UefiCpuPkg/CpuDxe/CpuDxe.h b/UefiCpuPkg/CpuDxe/CpuDxe.h
index 4861abee76..a25b35c6eb 100644
--- a/UefiCpuPkg/CpuDxe/CpuDxe.h
+++ b/UefiCpuPkg/CpuDxe/CpuDxe.h
@@ -52,6 +52,10 @@
                                        EFI_MEMORY_UCE   \
                                        )
 
+#define EFI_MEMORY_PAGETYPE_MASK      (EFI_MEMORY_RP  | \
+                                       EFI_MEMORY_XP  | \
+                                       EFI_MEMORY_RO    \
+                                       )
 
 /**
   Flush CPU data cache. If the instruction cache is fully coherent
@@ -261,5 +265,10 @@ SetDataSelectors (
   UINT16 Selector
   );
 
+VOID
+RefreshGcdMemoryAttributesFromPaging (
+  VOID
+  );
+
 #endif
 
diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c b/UefiCpuPkg/CpuDxe/CpuPageTable.c
index 2c61e7503e..bca4a497ac 100644
--- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
+++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
@@ -23,6 +23,8 @@
 #include <Library/DebugLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Protocol/MpService.h>
+
+#include "CpuDxe.h"
 #include "CpuPageTable.h"
 
 ///
@@ -767,6 +769,96 @@ AssignMemoryPageAttributes (
   return Status;
 }
 
+/**
+  Update GCD memory space attributes according to current page table setup.
+**/
+VOID
+RefreshGcdMemoryAttributesFromPaging (
+  VOID
+  )
+{
+  EFI_STATUS                          Status;
+  UINTN                               NumberOfDescriptors;
+  EFI_GCD_MEMORY_SPACE_DESCRIPTOR     *MemorySpaceMap;
+  PAGE_TABLE_LIB_PAGING_CONTEXT       PagingContext;
+  PAGE_ATTRIBUTE                      PageAttribute;
+  UINT64                              *PageEntry;
+  UINT64                              PageLength;
+  UINT64                              MemorySpaceLength;
+  UINT64                              Length;
+  UINT64                              BaseAddress;
+  UINT64                              PageStartAddress;
+  UINT64                              Attributes;
+  BOOLEAN                             DoUpdate;
+  UINTN                               Index;
+
+  //
+  // Assuming that memory space map returned is sorted already; otherwise sort
+  // them in the order of lowest address to highest address.
+  //
+  Status = gDS->GetMemorySpaceMap (&NumberOfDescriptors, &MemorySpaceMap);
+  ASSERT_EFI_ERROR (Status);
+
+  GetCurrentPagingContext (&PagingContext);
+
+  BaseAddress = 0;
+  PageLength  = 0;
+  for (Index = 0; Index < NumberOfDescriptors; Index++) {
+    if (MemorySpaceMap[Index].GcdMemoryType == EfiGcdMemoryTypeNonExistent) {
+      continue;
+    }
+
+    if (MemorySpaceMap[Index].BaseAddress >= (BaseAddress + PageLength)) {
+      //
+      // Current memory space starts at a new page. Resetting PageLength will
+      // trigger a retrieval of page attributes at new address.
+      //
+      PageLength = 0;
+    }
+
+    // Sync real page attributes to GCD
+    BaseAddress       = MemorySpaceMap[Index].BaseAddress;
+    MemorySpaceLength = MemorySpaceMap[Index].Length;
+    while (MemorySpaceLength > 0) {
+      if (PageLength == 0) {
+        PageEntry = GetPageTableEntry (&PagingContext, BaseAddress, &PageAttribute);
+        if (PageEntry == NULL) {
+          break;
+        }
+
+        //
+        // Note current memory space might start in the middle of a page
+        //
+        PageStartAddress  = (*PageEntry) & (UINT64)PageAttributeToMask(PageAttribute);
+        PageLength        = PageAttributeToLength (PageAttribute) - (BaseAddress - PageStartAddress);
+        Attributes        = GetAttributesFromPageEntry (PageEntry);
+
+        if (Attributes != (MemorySpaceMap[Index].Attributes & EFI_MEMORY_PAGETYPE_MASK)) {
+          DoUpdate = TRUE;
+          Attributes |= (MemorySpaceMap[Index].Attributes & ~EFI_MEMORY_PAGETYPE_MASK);
+        } else {
+          DoUpdate = FALSE;
+        }
+      }
+
+      Length = MIN (PageLength, MemorySpaceLength);
+      if (DoUpdate) {
+        gDS->SetMemorySpaceCapabilities (BaseAddress, Length, Attributes);
+        gDS->SetMemorySpaceAttributes (BaseAddress, Length, Attributes);
+        DEBUG ((DEBUG_INFO, "Update memory space attribute: [%02d] %016lx - %016lx (%08lx -> %08lx)\r\n",
+                             Index, BaseAddress, BaseAddress + Length - 1,
+                             MemorySpaceMap[Index].Attributes, Attributes));
+      }
+
+      PageLength        -= Length;
+      MemorySpaceLength -= Length;
+      BaseAddress       += Length;
+    }
+  }
+
+  FreePool (MemorySpaceMap);
+}
+
 /**
   Initialize the Page Table lib.
 **/
-- 
2.14.1.windows.1