1 files changed, 12 insertions, 0 deletions
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
index 741e4b7da2..271492a9d7 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
@@ -69,6 +69,7 @@ extern ASM_PFX(mXdSupported)
 global ASM_PFX(gPatchXdSupported)
 global ASM_PFX(gPatchSmiStack)
 global ASM_PFX(gPatchSmiCr3)
+global ASM_PFX(gPatch5LevelPagingSupport)
 global ASM_PFX(gcSmiHandlerTemplate)
 global ASM_PFX(gcSmiHandlerSize)
 
@@ -124,6 +125,17 @@ ProtFlatMode:
 ASM_PFX(gPatchSmiCr3):
     mov     cr3, rax
     mov     eax, 0x668                   ; as cr4.PGE is not set here, refresh cr3
+
+    mov     cl, strict byte 0            ; source operand will be patched
+ASM_PFX(gPatch5LevelPagingSupport):
+    cmp     cl, 0
+    je      SkipEnable5LevelPaging
+    ;
+    ; Enable 5-Level Paging bit
+    ;
+    bts     eax, 12                     ; Set LA57 bit (bit #12)
+SkipEnable5LevelPaging:
+
     mov     cr4, rax                    ; in PreModifyMtrrs() to flush TLB.
 ; Load TSS
     sub     esp, 8                      ; reserve room in stack