OvmfPkg/ResetVector: wire up 5-level paging for TDX

BSP workflow is quite simliar to the non-coco case.

TDX_WORK_AREA_PGTBL_READY is used to record the paging mode:
  1 == 4-level paging
  2 == 5-level paging

APs will look at TDX_WORK_AREA_PGTBL_READY to figure whenever
they should enable 5-level paging or not.

Signed-off-by: Gerd Hoffmann <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Laszlo Ersek <[email protected]>
[[email protected]: move "CheckForSev:" label into "%if PG_5_LEVEL" scope,
 as discussed with Gerd]
Cc: Jiewen Yao <[email protected]>
Cc: Oliver Steffen <[email protected]>
Cc: Michael Roth <[email protected]>
Cc: Erdem Aktas <[email protected]>
Cc: Min Xu <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Tom Lendacky <[email protected]>
[[email protected]: turn the "Cc:" message headers from Gerd's on-list
 posting into "Cc:" tags in the commit message, in order to pacify
 "PatchCheck.py"]

OvmfPkg/ResetVector/Ia32/IntelTdx.asm

@@ -179,7 +179,7 @@ InitTdx:
 ;
 ; Modified:  EAX, EDX
 ;
-; 0-NonTdx, 1-TdxBsp, 2-TdxAps
+; 0-NonTdx, 1-TdxBsp, 2-TdxAps, 3-TdxAps5Level
 ;
 CheckTdxFeaturesBeforeBuildPagetables:
     xor     eax, eax
@@ -200,6 +200,17 @@ TdxPostBuildPageTables:
     mov     byte[TDX_WORK_AREA_PGTBL_READY], 1
     OneTimeCallRet TdxPostBuildPageTables
 
+%if PG_5_LEVEL
+
+;
+; Set byte[TDX_WORK_AREA_PGTBL_READY] to 2
+;
+TdxPostBuildPageTables5Level:
+    mov     byte[TDX_WORK_AREA_PGTBL_READY], 2
+    OneTimeCallRet TdxPostBuildPageTables5Level
+
+%endif
+
 ;
 ; Check if TDX is enabled
 ;

OvmfPkg/ResetVector/Ia32/PageTables64.asm

@@ -44,6 +44,7 @@ BITS    32
 
 %define TDX_BSP         1
 %define TDX_AP          2
+%define TDX_AP_5_LEVEL  3
 
 ;
 ; For OVMF, build some initial page tables at
@@ -214,6 +215,13 @@ SetCr3ForPageTables64:
     je        TdxBspInit
     cmp       eax, TDX_AP
     je        SetCr3
+%if PG_5_LEVEL
+    cmp       eax, TDX_AP_5_LEVEL
+    jne       CheckForSev
+    Enable5LevelPaging
+    jmp       SetCr3
+CheckForSev:
+%endif
 
     ; Check whether the SEV is active and populate the SevEsWorkArea
     OneTimeCall   CheckSevFeatures
@@ -253,6 +261,14 @@ TdxBspInit:
     ; TDX BSP workflow
     ;
     ClearOvmfPageTables
+%if PG_5_LEVEL
+    Check5LevelPaging Tdx4Level
+    CreatePageTables5Level 0
+    OneTimeCall TdxPostBuildPageTables5Level
+    Enable5LevelPaging
+    jmp SetCr3
+Tdx4Level:
+%endif
     CreatePageTables4Level 0
     OneTimeCall TdxPostBuildPageTables
     jmp SetCr3