From fded08e74400fd0b76ad4733111e946f3ecea244 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 1 Mar 2024 08:43:53 +0100
Subject: [PATCH] OvmfPkg/ResetVector: improve page table flag names

Add comments, rename some of the PAGE_* flags and combined attributes.
Specifically use "LARGEPAGE" instead of "2M" because that bit is used
for both 2M and 1G large pages.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20240301074402.98625-2-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 | 39 +++++++++++++----------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
index 317cad430f..6fec6f2bee 100644
--- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
+++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
@@ -10,6 +10,7 @@
 
 BITS    32
 
+; common for all levels
 %define PAGE_PRESENT            0x01
 %define PAGE_READ_WRITE         0x02
 %define PAGE_USER_SUPERVISOR    0x04
@@ -17,25 +18,29 @@ BITS    32
 %define PAGE_CACHE_DISABLE     0x010
 %define PAGE_ACCESSED          0x020
 %define PAGE_DIRTY             0x040
-%define PAGE_PAT               0x080
 %define PAGE_GLOBAL           0x0100
-%define PAGE_2M_MBO            0x080
-%define PAGE_2M_PAT          0x01000
+
+; page table entries (level 1)
+%define PAGE_PTE_PAT           0x080
+
+; page directory entries (level 2+)
+%define PAGE_PDE_LARGEPAGE     0x080
+%define PAGE_PDE_PAT         0x01000
 
 %define PAGE_4K_PDE_ATTR (PAGE_ACCESSED + \
                           PAGE_DIRTY + \
                           PAGE_READ_WRITE + \
                           PAGE_PRESENT)
 
-%define PAGE_2M_PDE_ATTR (PAGE_2M_MBO + \
-                          PAGE_ACCESSED + \
-                          PAGE_DIRTY + \
-                          PAGE_READ_WRITE + \
-                          PAGE_PRESENT)
+%define PAGE_PDE_LARGEPAGE_ATTR (PAGE_PDE_LARGEPAGE + \
+                                 PAGE_ACCESSED + \
+                                 PAGE_DIRTY + \
+                                 PAGE_READ_WRITE + \
+                                 PAGE_PRESENT)
 
-%define PAGE_PDP_ATTR (PAGE_ACCESSED + \
-                       PAGE_READ_WRITE + \
-                       PAGE_PRESENT)
+%define PAGE_PDE_DIRECTORY_ATTR (PAGE_ACCESSED + \
+                                 PAGE_READ_WRITE + \
+                                 PAGE_PRESENT)
 
 %define TDX_BSP         1
 %define TDX_AP          2
@@ -84,19 +89,19 @@ clearPageTablesMemoryLoop:
     ;
     ; Top level Page Directory Pointers (1 * 512GB entry)
     ;
-    mov     dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDP_ATTR
+    mov     dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDE_DIRECTORY_ATTR
     mov     dword[PT_ADDR (4)], edx
 
     ;
     ; Next level Page Directory Pointers (4 * 1GB entries => 4GB)
     ;
-    mov     dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDP_ATTR
+    mov     dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDE_DIRECTORY_ATTR
     mov     dword[PT_ADDR (0x1004)], edx
-    mov     dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDP_ATTR
+    mov     dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDE_DIRECTORY_ATTR
     mov     dword[PT_ADDR (0x100C)], edx
-    mov     dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDP_ATTR
+    mov     dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDE_DIRECTORY_ATTR
     mov     dword[PT_ADDR (0x1014)], edx
-    mov     dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDP_ATTR
+    mov     dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDE_DIRECTORY_ATTR
     mov     dword[PT_ADDR (0x101C)], edx
 
     ;
@@ -107,7 +112,7 @@ pageTableEntriesLoop:
     mov     eax, ecx
     dec     eax
     shl     eax, 21
-    add     eax, PAGE_2M_PDE_ATTR
+    add     eax, PAGE_PDE_LARGEPAGE_ATTR
     mov     [ecx * 8 + PT_ADDR (0x2000 - 8)], eax
     mov     [(ecx * 8 + PT_ADDR (0x2000 - 8)) + 4], edx
     loop    pageTableEntriesLoop