Re: [PATCH 2/2] MdeModulePkg/PiSmmCpuDxeSmm: Check RegisterCpuInterruptHandler status

["Kinney, Michael D" <michael.d.kinney@intel.com>]

Jeff,

I agree that SMM modules that call 
EFI_SMM_CPU_SERVICE_PROTOCOL.RegisterExceptionHandler()
always need to check for error return status and we do
not want an ASSERT() there.

Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>

Mike




> -----Original Message-----
> From: Fan, Jeff
> Sent: Wednesday, November 16, 2016 6:54 PM
> To: Kinney, Michael D <michael.d.kinney@intel.com>; edk2-devel@lists.01.org
> Cc: Tian, Feng <feng.tian@intel.com>
> Subject: RE: [PATCH 2/2] MdeModulePkg/PiSmmCpuDxeSmm: Check
> RegisterCpuInterruptHandler status
> 
> Mike,
> 
> I think it's not necessary to move ASSERT() to SmmRegisterExceptionHandler()
> implementation.
> 
> Because PiSmmCpuDxeSmm will invoke SmmRegisterExceptionHandler() at module entry
> point function as my patch showed, it could make sure PiSmmCpuDxeSmm choose the
> correct instance.
> 
> Other module invoke may check SmmRegisterExceptionHandler the return status for other
> choice per design.
> For example:
>     @retval EFI_ALREADY_STARTED   InterruptHandler is not NULL, and a handler for
> InterruptType was previously installed.
> 
> Thanks!
> Jeff
> 
> 
> -----Original Message-----
> From: Kinney, Michael D
> Sent: Thursday, November 17, 2016 12:29 AM
> To: Fan, Jeff; edk2-devel@lists.01.org; Kinney, Michael D
> Cc: Tian, Feng
> Subject: RE: [PATCH 2/2] MdeModulePkg/PiSmmCpuDxeSmm: Check
> RegisterCpuInterruptHandler status
> 
> Jeff,
> 
> Shouldn't this ASSERT() be moved into the implementation of
> SmmRegisterExceptionHandler()?  This will make sure the PiSmmCpuDxeSmm driver uses
> the right lib instance for exceptions that module registers and for exceptions other
> SMM modules register through the EFI_SMM_CPU_SERVICE_PROTOCOL.
> 
> Mike
> 
> > -----Original Message-----
> > From: Fan, Jeff
> > Sent: Wednesday, November 16, 2016 6:34 AM
> > To: edk2-devel@lists.01.org
> > Cc: Tian, Feng <feng.tian@intel.com>; Kinney, Michael D
> > <michael.d.kinney@intel.com>
> > Subject: [PATCH 2/2] MdeModulePkg/PiSmmCpuDxeSmm: Check
> > RegisterCpuInterruptHandler status
> >
> > Once platform selects the incorrect instance, the caller could know it
> > from return status and ASSERT().
> >
> > Cc: Feng Tian <feng.tian@intel.com>
> > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > Contributed-under: TianoCore Contribution Agreement 1.0
> > Signed-off-by: Jeff Fan <jeff.fan@intel.com>
> > ---
> >  UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c | 4 +++-
> >  UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c   | 5 ++++-
> >  UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c  | 4 +++-
> >  3 files changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
> > b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
> > index a871bef..f2e2ceb 100644
> > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
> > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
> > @@ -27,6 +27,7 @@ SmmInitPageTable (
> >  {
> >    UINTN                             PageFaultHandlerHookAddress;
> >    IA32_IDT_GATE_DESCRIPTOR          *IdtEntry;
> > +  EFI_STATUS                        Status;
> >
> >    //
> >    // Initialize spin lock
> > @@ -49,7 +50,8 @@ SmmInitPageTable (
> >      //
> >      // Register SMM Page Fault Handler
> >      //
> > -    SmmRegisterExceptionHandler (&mSmmCpuService, EXCEPT_IA32_PAGE_FAULT,
> > SmiPFHandler);
> > +    Status = SmmRegisterExceptionHandler (&mSmmCpuService,
> > + EXCEPT_IA32_PAGE_FAULT,
> > SmiPFHandler);
> > +    ASSERT_EFI_ERROR (Status);
> >    }
> >
> >    //
> > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
> > b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
> > index 329574e..350a6a2 100644
> > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
> > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
> > @@ -1384,5 +1384,8 @@ InitIdtr (
> >    VOID
> >    )
> >  {
> > -  SmmRegisterExceptionHandler (&mSmmCpuService, EXCEPT_IA32_DEBUG,
> > DebugExceptionHandler);
> > +  EFI_STATUS                        Status;
> > +
> > +  Status = SmmRegisterExceptionHandler (&mSmmCpuService,
> > + EXCEPT_IA32_DEBUG,
> > DebugExceptionHandler);
> > +  ASSERT_EFI_ERROR (Status);
> >  }
> > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> > b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> > index 9cee784..c49fb26 100644
> > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> > @@ -102,6 +102,7 @@ SmmInitPageTable (
> >    UINTN                             Index;
> >    UINTN                             PageFaultHandlerHookAddress;
> >    IA32_IDT_GATE_DESCRIPTOR          *IdtEntry;
> > +  EFI_STATUS                        Status;
> >
> >    //
> >    // Initialize spin lock
> > @@ -160,7 +161,8 @@ SmmInitPageTable (
> >      //
> >      // Register Smm Page Fault Handler
> >      //
> > -    SmmRegisterExceptionHandler (&mSmmCpuService, EXCEPT_IA32_PAGE_FAULT,
> > SmiPFHandler);
> > +    Status = SmmRegisterExceptionHandler (&mSmmCpuService,
> > + EXCEPT_IA32_PAGE_FAULT,
> > SmiPFHandler);
> > +    ASSERT_EFI_ERROR (Status);
> >    }
> >
> >    //
> > --
> > 2.9.3.windows.2