From 52e44713d23de600ac7eb12bdfa0600abd2294eb Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 1 Mar 2024 08:43:54 +0100
Subject: [PATCH] OvmfPkg/ResetVector: add ClearOvmfPageTables macro

Move code to clear the page tables to a nasm macro.
No functional change.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20240301074402.98625-3-kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Oliver Steffen <osteffen@redhat.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
[lersek@redhat.com: 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/PageTables64.asm | 35 ++++++++++++-----------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
index 6fec6f2bee..378ba2feeb 100644
--- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
+++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
@@ -45,6 +45,24 @@ BITS    32
 %define TDX_BSP         1
 %define TDX_AP          2
 
+;
+; For OVMF, build some initial page tables at
+; PcdOvmfSecPageTablesBase - (PcdOvmfSecPageTablesBase + 0x6000).
+;
+; This range should match with PcdOvmfSecPageTablesSize which is
+; declared in the FDF files.
+;
+; At the end of PEI, the pages tables will be rebuilt into a
+; more permanent location by DxeIpl.
+;
+%macro ClearOvmfPageTables 0
+    mov     ecx, 6 * 0x1000 / 4
+    xor     eax, eax
+.clearPageTablesMemoryLoop:
+    mov     dword[ecx * 4 + PT_ADDR (0) - 4], eax
+    loop    .clearPageTablesMemoryLoop
+%endmacro
+
 ;
 ; Modified:  EAX, EBX, ECX, EDX
 ;
@@ -69,22 +87,7 @@ SetCr3ForPageTables64:
     OneTimeCall   GetSevCBitMaskAbove31
 
 ClearOvmfPageTables:
-    ;
-    ; For OVMF, build some initial page tables at
-    ; PcdOvmfSecPageTablesBase - (PcdOvmfSecPageTablesBase + 0x6000).
-    ;
-    ; This range should match with PcdOvmfSecPageTablesSize which is
-    ; declared in the FDF files.
-    ;
-    ; At the end of PEI, the pages tables will be rebuilt into a
-    ; more permanent location by DxeIpl.
-    ;
-
-    mov     ecx, 6 * 0x1000 / 4
-    xor     eax, eax
-clearPageTablesMemoryLoop:
-    mov     dword[ecx * 4 + PT_ADDR (0) - 4], eax
-    loop    clearPageTablesMemoryLoop
+    ClearOvmfPageTables
 
     ;
     ; Top level Page Directory Pointers (1 * 512GB entry)