1 files changed, 20 insertions, 0 deletions
diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm b/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
index f188da20ba..165cebcfaa 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
@@ -17,8 +17,28 @@ SetCr3ForPageTables64:
     ;
     ; These pages are built into the ROM image in X64/PageTables.asm
     ;
+%ifdef USE_5_LEVEL_PAGE_TABLE
+    mov     eax, 0
+    cpuid
+    cmp     eax, 07h                    ; check if basic CPUID leaf contains leaf 07
+    jb      NotSupport5LevelPaging      ; 5level paging not support, downgrade to 4level paging
+    mov     eax, 07h                    ; check cpuid leaf 7, subleaf 0
+    mov     ecx, 0
+    cpuid
+    bt      ecx, 16                     ; [Bits 16] Supports 5-level paging if 1.
+    jnc     NotSupport5LevelPaging      ; 5level paging not support, downgrade to 4level paging
+    mov     eax, ADDR_OF(Pml5)
+    mov     cr3, eax
+    mov     eax, cr4
+    bts     eax, 12                     ; Set LA57=1.
+    mov     cr4, eax
+    jmp     SetCr3Done
+NotSupport5LevelPaging:
+%endif
+
     mov     eax, ADDR_OF(Pml4)
     mov     cr3, eax
+SetCr3Done:
 
     OneTimeCallRet SetCr3ForPageTables64