Ring3: Set 1G User pages as not present by default, fixed padding.

acidanthera · Nov 29, 2024 · 1bde91a · 1bde91a
1 parent 63dcc29
commit 1bde91a
Show file tree

Hide file tree

Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/MdeModulePkg/Core/Dxe/SysCall/X64/InitializeMsr.c b/MdeModulePkg/Core/Dxe/SysCall/X64/InitializeMsr.c
@@ -111,7 +111,7 @@ MakeUserPageTableTemplate (
           //
           PageDirectory1GEntry->Uint64         = (UINT64)PageAddress | PageTableInfo->AddressEncMask;
           PageDirectory1GEntry->Bits.ReadWrite = 1;
-          PageDirectory1GEntry->Bits.Present   = 1;
+          PageDirectory1GEntry->Bits.Present   = 0;
           PageDirectory1GEntry->Bits.MustBe1   = 1;
         }
       } else {

diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm
@@ -63,11 +63,14 @@ global ASM_PFX(UserPageTable)
 ASM_PFX(UserPageTable):
   resq 1
 
-ALIGN   4096
 global ASM_PFX(mSwitchCr3Flag)
 ASM_PFX(mSwitchCr3Flag):
   db 0x0
 
+ALIGN   4096
+Padding:
+  db 0x0
+
 DEFAULT REL
 SECTION .text