Add a macro USE_5_LEVEL_PAGE_TABLE to determine whether to create
5 level page table.
If macro USE_5_LEVEL_PAGE_TABLE is defined, PML5Table is created
at (4G-12K), while PML4Table is at (4G-16K). In runtime check, if
5level paging is supported, use PML5Table, otherwise, use PML4Table.
If macro USE_5_LEVEL_PAGE_TABLE is not defined, to save space, 5level
paging is not created, and 4level paging is at (4G-12K) and be used.

Cc: Eric Dong <eric.d...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Rahul Kumar <rahul1.ku...@intel.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
Cc: Debkumar De <debkumar...@intel.com>
Cc: Catharine West <catharine.w...@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang....@intel.com>
---
 .../ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm  | 25 +++++++++++++++++--
 .../ResetVector/Vtf0/Ia32/PageTables64.asm    | 24 ------------------
 UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb        |  1 -
 .../ResetVector/Vtf0/X64/PageTables.asm       |  9 +++++++
 4 files changed, 32 insertions(+), 27 deletions(-)
 delete mode 100644 UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm

diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm 
b/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm
index 6891397c2a..f119f941a5 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm
@@ -2,7 +2,7 @@
 ; @file
 ; Transition from 32 bit flat protected mode into 64 bit flat protected mode
 ;
-; Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2008 - 2023, Intel Corporation. All rights reserved.<BR>
 ; SPDX-License-Identifier: BSD-2-Clause-Patent
 ;
 ;------------------------------------------------------------------------------
@@ -14,7 +14,28 @@ BITS    32
 ;
 Transition32FlatTo64Flat:
 
-    OneTimeCall SetCr3ForPageTables64
+%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:
 
     mov     eax, cr4
     bts     eax, 5                      ; enable PAE
diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm 
b/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
deleted file mode 100644
index f188da20ba..0000000000
--- a/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
+++ /dev/null
@@ -1,24 +0,0 @@
-;------------------------------------------------------------------------------
-; @file
-; Sets the CR3 register for 64-bit paging
-;
-; Copyright (c) 2008 - 2023, Intel Corporation. All rights reserved.<BR>
-; SPDX-License-Identifier: BSD-2-Clause-Patent
-;
-;------------------------------------------------------------------------------
-
-BITS    32
-
-;
-; Modified:  EAX
-;
-SetCr3ForPageTables64:
-
-    ;
-    ; These pages are built into the ROM image in X64/PageTables.asm
-    ;
-    mov     eax, ADDR_OF(Pml4)
-    mov     cr3, eax
-
-    OneTimeCallRet SetCr3ForPageTables64
-
diff --git a/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb 
b/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
index 136361e62c..5a6563bd34 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
+++ b/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
@@ -54,7 +54,6 @@
 
 %ifdef ARCH_X64
 %include "Ia32/Flat32ToFlat64.asm"
-%include "Ia32/PageTables64.asm"
 %endif
 
 %include "Ia16/Real16ToFlat32.asm"
diff --git a/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables.asm 
b/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables.asm
index 4ff68cddef..5aa229eb14 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables.asm
@@ -80,4 +80,13 @@ Pml4:
     ;
     DQ      PG_NLE(Pdp)
     TIMES   0x1000 - ($ - Pml4) DB 0
+
+%ifdef USE_5_LEVEL_PAGE_TABLE
+Pml5:
+    ;
+    ; Pml5 table (only first entry is present, pointing to Pml4)
+    ;
+    DQ      PG_NLE(Pml4)
+    TIMES   0x1000 - ($ - Pml5) DB 0
+%endif
 EndOfPageTables:
-- 
2.31.1.windows.1



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