Re: [PATCH 09/17] OvmfPkg/PlatformDebugLibIoPort: Add a new api DebugVPrint

["Gao, Zhichao" <zhichao.gao@intel.com>]

Thanks for your careful review.

> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Thursday, March 14, 2019 9:08 PM
> To: Gao, Zhichao <zhichao.gao@intel.com>; edk2-devel@lists.01.org
> Cc: Justen, Jordan L <jordan.l.justen@intel.com>; Ard Biesheuvel
> <ard.biesheuvel@linaro.org>; Gao, Liming <liming.gao@intel.com>; Sean
> Brogan <sean.brogan@microsoft.com>; Michael Turner
> <Michael.Turner@microsoft.com>; Bret Barkelew
> <Bret.Barkelew@microsoft.com>
> Subject: Re: [PATCH 09/17] OvmfPkg/PlatformDebugLibIoPort: Add a new api
> DebugVPrint
> 
> On 03/14/19 10:03, Zhichao Gao wrote:
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1395
> >
> > Add a new api DebugVPrint implementation in the DebugLib instance.
> > This api would expose a print routine with VaList parameter.
> >
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
> > Cc: Jordan Justen <jordan.l.justen@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > Cc: Liming Gao <liming.gao@intel.com>
> > Cc: Sean Brogan <sean.brogan@microsoft.com>
> > Cc: Michael Turner <Michael.Turner@microsoft.com>
> > Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
> > ---
> >  OvmfPkg/Library/PlatformDebugLibIoPort/DebugLib.c | 41
> > +++++++++++++++++++----
> >  1 file changed, 35 insertions(+), 6 deletions(-)
> >
> > diff --git a/OvmfPkg/Library/PlatformDebugLibIoPort/DebugLib.c
> > b/OvmfPkg/Library/PlatformDebugLibIoPort/DebugLib.c
> > index 36cde54976..1e64eeec11 100644
> > --- a/OvmfPkg/Library/PlatformDebugLibIoPort/DebugLib.c
> > +++ b/OvmfPkg/Library/PlatformDebugLibIoPort/DebugLib.c
> > @@ -2,7 +2,7 @@
> >    Base Debug library instance for QEMU debug port.
> >    It uses PrintLib to send debug messages to a fixed I/O port.
> >
> > -  Copyright (c) 2006 - 2015, Intel Corporation. All rights
> > reserved.<BR>
> > +  Copyright (c) 2006 - 2019, Intel Corporation. All rights
> > + reserved.<BR>
> >    Copyright (c) 2012, Red Hat, Inc.<BR>
> >    This program and the accompanying materials
> >    are licensed and made available under the terms and conditions of
> > the BSD License @@ -51,9 +51,41 @@ DebugPrint (
> >    IN  CONST CHAR8  *Format,
> >    ...
> >    )
> > +{
> > +  VA_LIST         Marker;
> > +
> > +  ASSERT(Format != NULL);
> 
> (1) I think this ASSERT() is redundant.  The rest of this function will work fine
> with the ASSERT() removed, and the DebugVPrint() function will itself
> contain an ASSERT(), with the same condition. So I'd prefer removing this one.
> (The function-level comments will remain valid.)

You are right. I would remove it.

> 
> > +
> > +  VA_START(Marker, Format);
> > +  DebugVPrint(ErrorLevel, Format, Marker);  VA_END(Marker);
> 
> (2) Please insert a space character before each opening parenthesis.

Good catch. Thanks.

> 
> > +}
> > +
> > +/**
> > +  Prints a debug message to the debug output device if the specified error
> level is enabled.
> > +
> > +  If any bit in ErrorLevel is also set in DebugPrintErrorLevelLib
> > + function  GetDebugPrintErrorLevel (), then print the message
> > + specified by Format and the  associated variable argument list to the
> debug output device.
> > +
> > +  If Format is NULL, then ASSERT().
> > +  If the length of the message string specificed by Format is larger
> > + than the maximum allowable  record length, then directly return and not
> print it.
> 
> (3) The last sentence is not enforced by the implementation.
> 
> We should
> - either implement the check,
> - or extend the sentence, saying that there is no such limit in this library
> instance,
> - or remove the sentence.
> 
> I think I'd prefer simply removing the sentence, given that the
> DebugPrint() comments lack it as well.

Agree with you. Removing it is better.

> 
> > +
> > +  @param  ErrorLevel    The error level of the debug message.
> > +  @param  Format        Format string for the debug message to print.
> > +  @param  VaListMarker  VA_LIST marker for the variable argument list.
> > +
> > +**/
> > +VOID
> > +EFIAPI
> > +DebugVPrint (
> > +  IN  UINTN        ErrorLevel,
> > +  IN  CONST CHAR8  *Format,
> > +  IN  VA_LIST       VaListMarker
> > +  )
> >  {
> >    CHAR8    Buffer[MAX_DEBUG_MESSAGE_LENGTH];
> > -  VA_LIST  Marker;
> >    UINTN    Length;
> >
> >    //
> > @@ -72,9 +104,7 @@ DebugPrint (
> >    //
> >    // Convert the DEBUG() message to an ASCII String
> >    //
> > -  VA_START (Marker, Format);
> > -  Length = AsciiVSPrint (Buffer, sizeof (Buffer), Format, Marker);
> > -  VA_END (Marker);
> > +  Length = AsciiVSPrint (Buffer, sizeof (Buffer), Format,
> > + VaListMarker);
> >
> >    //
> >    // Send the print string to the debug I/O port @@ -82,7 +112,6 @@
> > DebugPrint (
> >    IoWriteFifo8 (PcdGet16 (PcdDebugIoPort), Length, Buffer);  }
> >
> > -
> >  /**
> >    Prints an assert message containing a filename, line number, and
> description.
> >    This may be followed by a breakpoint or a dead loop.
> >
> 
> (4) This hunk (the last hunk of the patch), which only removes an empty line,
> looks superfluous to me. I suggest dropping it.

My coding style is putting one blank line between two function. It seems the lib prefers to putting two blank line. I would unify it for this lib.

> 
> Thanks
> Laszlo

Thanks,
Zhichao