Changeset 81195 in vbox for trunk/src/VBox/Devices/EFI/Firmware/UefiCpuPkg

Timestamp:

Oct 9, 2019 8:04:51 PM (5 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

133846

Message:

EFI/Firmware: Should always use atomics when updating 64-bit page table entries (see PGMSHWPTEPAE_ATOMIC_SET and such). Cache the old page table entry value instead of reading it 512 times when converting the tables. Do similar stuff for ConvertPageEntryAttribute and make it skip writing the same value back. bugref:4643

File:

• trunk/src/VBox/Devices/EFI/Firmware/UefiCpuPkg/CpuDxe/CpuPageTable.c (modified) (8 diffs)

trunk/src/VBox/Devices/EFI/Firmware/UefiCpuPkg/CpuDxe/CpuPageTable.c

@@ -18 +18 @@
 #include <Register/Intel/Cpuid.h>
 #include <Register/Intel/Msr.h>
+#ifdef VBOX
+# define IN_RING0
+# include <iprt/asm.h>
+#endif
 
 #include "CpuDxe.h"
@@ -97 +101 @@
 UINT64                    *(*mLastPFEntryPointer)[MAX_PF_ENTRY_COUNT];
 
+#ifdef VBOX
+/**
+ Safe page table entry write function, make 104% sure the compiler won't
+ split up the access (fatal if modifying entries for current code or data).
+
+ @param[in] PageEntry        The page table entry to modify.*
+ @param[in] CurrentPageEntry The old page table value (for cmpxchg8b).
+ @param[in] NewPageEntry     What to write.
+**/
+static VOID SafePageTableEntryWrite64 (UINT64 volatile *PageEntry, UINT64 CurrentPageEntry, UINT64 NewPageEntry)
+{
+# ifdef VBOX
+  ASMAtomicWriteU64(PageEntry, NewPageEntry); RT_NOREF(CurrentPageEntry);
+# else
+  for (;;) {
+    UINT64 CurValue = InterlockedCompareExchange64(PageEntry, CurrentPageEntry, NewPageEntry);
+    if (CurValue == CurrentPageEntry)
+      return;
+    CurrentPageEntry = CurValue;
+  }
+# endif
+}
+#endif
+
 /**
  Check if current execution environment is in SMM mode or not, via
@@ -388 +416 @@
 ConvertPageEntryAttribute (
   IN  PAGE_TABLE_LIB_PAGING_CONTEXT     *PagingContext,
+#ifdef VBOX
+  IN  UINT64 volatile                   *PageEntry,
+#else
   IN  UINT64                            *PageEntry,
+#endif
   IN  UINT64                            Attributes,
   IN  PAGE_ACTION                       PageAction,
@@ -461 +493 @@
     }
   }
+#ifndef VBOX
   *PageEntry = NewPageEntry;
+#endif
   if (CurrentPageEntry != NewPageEntry) {
+#ifdef VBOX
+    SafePageTableEntryWrite64 (PageEntry, CurrentPageEntry, NewPageEntry);
+#endif
     *IsModified = TRUE;
     DEBUG ((DEBUG_VERBOSE, "ConvertPageEntryAttribute 0x%lx", CurrentPageEntry));
@@ -519 +556 @@
 SplitPage (
 #ifdef VBOX
-  IN  volatile UINT64                   *PageEntry,
+  IN  UINT64 volatile                   *PageEntry,
 #else
   IN  UINT64                            *PageEntry,
@@ -529 +566 @@
 {
   UINT64   BaseAddress;
+#ifdef VBOX
+  UINT64   CurrentPageEntry;
+#endif
   UINT64   *NewPageEntry;
   UINTN    Index;
@@ -552 +592 @@
         return RETURN_OUT_OF_RESOURCES;
       }
+#ifdef VBOX
+      CurrentPageEntry = *PageEntry;
+      BaseAddress = CurrentPageEntry & ~AddressEncMask & PAGING_2M_ADDRESS_MASK_64;
+#else
       BaseAddress = *PageEntry & ~AddressEncMask & PAGING_2M_ADDRESS_MASK_64;
+#endif
       for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {
+#ifdef VBOX
+        NewPageEntry[Index] = (BaseAddress + SIZE_4KB * Index) | AddressEncMask | (CurrentPageEntry & PAGE_PROGATE_BITS);
+#else
         NewPageEntry[Index] = (BaseAddress + SIZE_4KB * Index) | AddressEncMask | ((*PageEntry) & PAGE_PROGATE_BITS);
-      }
+#endif
+      }
+#ifdef VBOX
+      SafePageTableEntryWrite64 (PageEntry, CurrentPageEntry,
+                                 (UINT64)(UINTN)NewPageEntry | AddressEncMask | (CurrentPageEntry & PAGE_ATTRIBUTE_BITS));
+#else
       (*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_ATTRIBUTE_BITS);
+#endif
       return RETURN_SUCCESS;
     } else {
@@ -573 +627 @@
         return RETURN_OUT_OF_RESOURCES;
       }
+#ifdef VBOX
+      CurrentPageEntry = *PageEntry;
+      BaseAddress = CurrentPageEntry & ~AddressEncMask  & PAGING_1G_ADDRESS_MASK_64;
+#else
       BaseAddress = *PageEntry & ~AddressEncMask  & PAGING_1G_ADDRESS_MASK_64;
+#endif
       for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {
+#ifdef VBOX
+        NewPageEntry[Index] = (BaseAddress + SIZE_2MB * Index) | AddressEncMask | IA32_PG_PS | (CurrentPageEntry & PAGE_PROGATE_BITS);
+#else
         NewPageEntry[Index] = (BaseAddress + SIZE_2MB * Index) | AddressEncMask | IA32_PG_PS | ((*PageEntry) & PAGE_PROGATE_BITS);
-      }
+#endif
+      }
+#ifdef VBOX
+      SafePageTableEntryWrite64 (PageEntry, CurrentPageEntry,
+                                 (UINT64)(UINTN)NewPageEntry | AddressEncMask | (CurrentPageEntry & PAGE_ATTRIBUTE_BITS));
+#else
       (*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_ATTRIBUTE_BITS);
+#endif
       return RETURN_SUCCESS;
     } else {