Re: [edk2-devel] [PATCH v2 1/1] OvmfPkg/ResetVector: send post codes to qemu debug console

["Erdem Aktas via groups.io" <erdemaktas=google.com@groups.io>]

On Fri, Jan 26, 2024 at 8:16 AM Tom Lendacky <thomas.lendacky@amd.com> wrote:
>
> On 1/26/24 08:29, Gerd Hoffmann wrote:
> > Neat when doing ResetVector coding.
> > Incompatible with TDX and SEV, therefore not enabled by default.
> >
> > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>
> Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
>
Acked-by: Erdem Aktas <erdemaktas@google.com>
>
> > ---
> >   OvmfPkg/ResetVector/QemuDebugCon.asm  | 35 +++++++++++++++++++++++++++
> >   OvmfPkg/ResetVector/ResetVector.nasmb |  4 +++
> >   2 files changed, 39 insertions(+)
> >   create mode 100644 OvmfPkg/ResetVector/QemuDebugCon.asm
> >
> > diff --git a/OvmfPkg/ResetVector/QemuDebugCon.asm b/OvmfPkg/ResetVector/QemuDebugCon.asm
> > new file mode 100644
> > index 000000000000..e385ca1be83a
> > --- /dev/null
> > +++ b/OvmfPkg/ResetVector/QemuDebugCon.asm
> > @@ -0,0 +1,35 @@
> > +;------------------------------------------------------------------------------
> > +; @file
> > +; qemu debug console support macros (based on serial port macros)
> > +;
> > +; Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
> > +; SPDX-License-Identifier: BSD-2-Clause-Patent
> > +;
> > +;------------------------------------------------------------------------------
> > +
> > +%macro  debugShowCharacter 1
> > +    mov     dx, 0x402
> > +    mov     al, %1
> > +    out     dx, al
> > +%endmacro
> > +
> > +%macro  debugShowHexDigit 1
> > +  %if (%1 < 0xa)
> > +    debugShowCharacter BYTE ('0' + (%1))
> > +  %else
> > +    debugShowCharacter BYTE ('a' + ((%1) - 0xa))
> > +  %endif
> > +%endmacro
> > +
> > +%macro  debugShowPostCode 1
> > +    debugShowHexDigit (((%1) >> 4) & 0xf)
> > +    debugShowHexDigit ((%1) & 0xf)
> > +    debugShowCharacter `\r`
> > +    debugShowCharacter `\n`
> > +%endmacro
> > +
> > +BITS    16
> > +
> > +%macro  debugInitialize 0
> > +    ; not required
> > +%endmacro
> > diff --git a/OvmfPkg/ResetVector/ResetVector.nasmb b/OvmfPkg/ResetVector/ResetVector.nasmb
> > index 5832aaa8abf7..69ce43ef6a96 100644
> > --- a/OvmfPkg/ResetVector/ResetVector.nasmb
> > +++ b/OvmfPkg/ResetVector/ResetVector.nasmb
> > @@ -40,6 +40,10 @@
> >     %include "Port80Debug.asm"
> >   %elifdef DEBUG_SERIAL
> >     %include "SerialDebug.asm"
> > +%elif 0
> > +; Set ^ this to 1 to enable postcodes on the qemu debug console.
> > +; Disabled by default because it is incompatible with SEV and TDX.
> > +  %include "QemuDebugCon.asm"
> >   %else
> >     %include "DebugDisabled.asm"
> >   %endif


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