[PATCH V3 08/10] OvmfPkg: Add Init32

["Min Xu" <min.m.xu@intel.com>]

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

Init32.asm is the entry point of doing the 32-bit protected mode
initialization. Here ReloadFlat32 is called. After that InitTdx is called
to do Tdx initialization if it is Tdx guests. In the future if SEV has
something to initialize, InitSev (for example) can be called in Init32.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 OvmfPkg/ResetVector/Ia32/Init32.asm | 32 +++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 OvmfPkg/ResetVector/Ia32/Init32.asm

diff --git a/OvmfPkg/ResetVector/Ia32/Init32.asm b/OvmfPkg/ResetVector/Ia32/Init32.asm
new file mode 100644
index 000000000000..fb78f6856f0a
--- /dev/null
+++ b/OvmfPkg/ResetVector/Ia32/Init32.asm
@@ -0,0 +1,32 @@
+;------------------------------------------------------------------------------
+; @file
+;   32-bit initialization code
+;
+; Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+BITS 32
+
+;
+; Modified:  EAX, EBX, ECX, EDX, EBP, EDI, ESP
+;
+Init32:
+    ;
+    ; Save EBX in EBP because EBX will be changed in ReloadFlat32
+    ;
+    mov     ebp, ebx
+
+    ;
+    ; First load the GDT and jump to Flat32 mode
+    ;
+    OneTimeCall ReloadFlat32
+
+    ;
+    ; Initialization of Tdx
+    ;
+    OneTimeCall  InitTdx
+
+    OneTimeCallRet Init32
+
-- 
2.29.2.windows.2