[edk2-devel] [PATCH V2 3/4] UefiCpuPkg/ResetVector: Add Main32 entry point in Main.asm

[Min Xu]

On July 25, 2021 2:08 PM, Yao, Jiewen wrote:
> Current OvmfPkg Reser vector is a mess (see my previous email).
> I also compared the ResetVector code in UefiCpuPkg and OvmfPkg. There
> are already duplication/override.
> 
> I suggest we just drop UefiCpuPkg change, and focus on improving OvmfPkg.
> If we need add something in UefiCpuPkg, let's copy the file to OvmfPkg and
> update there.
> 
Do you mean we create the Main.asm in OvmfPkg/ResetVector/ and update
the changes in this Main.asm?
>
> I really don't want to mess up UefiCpuPkg at this moment.
> We can make a better architecture to share reset vector in virtual BIOS and
> physical BIOS later. But at this moment, let's finish the virtual BIOS
> architecture at first.
> 
> Thank you
> Yao Jiewen
> 
> > -----Original Message-----
> > From: Xu, Min M <min.m.xu at intel.com>
> > Sent: Thursday, July 22, 2021 1:52 PM
> > To: devel at edk2.groups.io
> > Cc: Xu, Min M <min.m.xu at intel.com>; Dong, Eric <eric.dong at intel.com>;
> > Ni, Ray <ray.ni at intel.com>; Yao, Jiewen <jiewen.yao at intel.com>
> > Subject: [PATCH V2 3/4] UefiCpuPkg/ResetVector: Add Main32 entry point
> > in Main.asm
> >
> > RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
> >
> > In Tdx all CPUs "reset" to run on 32-bit protected mode with flat
> > descriptor (paging disabled). Main32 entry point is added in
> > UefiCpuPkg/ResetVector/Vtf0/Main.asm so that Main.asm can support the
> > 32-bit protected mode.
> >
> > Init32.asm is the 32-bit initialization code. It is a null stub in
> > UefiCpuPkg. The actual initialization can be implemented in the
> > platform (OvmfPkg/ResetVector/Ia32/Init32.asm is the example.)
> >
> > Cc: Eric Dong <eric.dong at intel.com>
> > Cc: Ray Ni <ray.ni at intel.com>
> > Cc: Jiewen Yao <jiewen.yao at intel.com>
> > Signed-off-by: Min Xu <min.m.xu at intel.com>
> > ---
> >  UefiCpuPkg/ResetVector/Vtf0/Ia32/Init32.asm | 13 +++++++++++++
> >  UefiCpuPkg/ResetVector/Vtf0/Main.asm        | 14 ++++++++++++++
> >  UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb      |  2 +-
> >  3 files changed, 28 insertions(+), 1 deletion(-)  create mode 100644
> > UefiCpuPkg/ResetVector/Vtf0/Ia32/Init32.asm
> >
> > diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/Init32.asm
> > b/UefiCpuPkg/ResetVector/Vtf0/Ia32/Init32.asm
> > new file mode 100644
> > index 000000000000..0cdae4a4a84a
> > --- /dev/null
> > +++ b/UefiCpuPkg/ResetVector/Vtf0/Ia32/Init32.asm
> > @@ -0,0 +1,13 @@
> > +;--------------------------------------------------------------------
> > +----------
> > +; @file
> > +;   32-bit initialization code.
> > +; Copyright (c) 2021, Intel Corporation. All rights reserved.<BR> ;
> > +SPDX-License-Identifier: BSD-2-Clause-Patent ;
> > +;--------------------------------------------------------------------
> > +----------
> > +
> > +BITS 32
> > +
> > +Init32:
> > +    nop
> > +    OneTimeCallRet Init32
> > diff --git a/UefiCpuPkg/ResetVector/Vtf0/Main.asm
> > b/UefiCpuPkg/ResetVector/Vtf0/Main.asm
> > index 19d08482f831..4920c6937e1b 100644
> > --- a/UefiCpuPkg/ResetVector/Vtf0/Main.asm
> > +++ b/UefiCpuPkg/ResetVector/Vtf0/Main.asm
> > @@ -36,6 +36,20 @@ Main16:
> >
> >  BITS    32
> >
> > +%ifdef ARCH_X64
> > +
> > +    jmp SearchBfv
> > +
> > +;
> > +; Entry point of Main32
> > +;
> > +Main32:
> > +
> > +    OneTimeCall Init32
> > +
> > +%endif
> > +
> > +SearchBfv:
> >      ;
> >      ; Search for the Boot Firmware Volume (BFV)
> >      ;
> > diff --git a/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
> > b/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
> > index 493738c79c1c..6493b9863c48 100644
> > --- a/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
> > +++ b/UefiCpuPkg/ResetVector/Vtf0/Vtf0.nasmb
> > @@ -51,7 +51,7 @@
> >  %include "Ia32/SearchForSecEntry.asm"
> >
> >  %ifdef ARCH_X64
> > -%include "Ia32/Flat32ToFlat64.asm"
> > +%include "Ia32/Init32.asm"
> >  %include "Ia32/PageTables64.asm"
> >  %endif
> >
> > --
> > 2.29.2.windows.2



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