Re: [edk2-devel] [PATCH] UefiCpuPkg/MicrocodeMeasurementDxe: Fix exception

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

Hi Ray,

It is in an error path.  My guess is that this error path has not been used
since this bug was introduced.

Can you please merge this fix?

Mike

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ni, Ray
> Sent: Tuesday, March 7, 2023 3:24 PM
> To: devel@edk2.groups.io; Reyes, Darbin <darbin.reyes@intel.com>
> Cc: Narey, Jacob <jacob.narey@intel.com>
> Subject: Re: [edk2-devel] [PATCH] UefiCpuPkg/MicrocodeMeasurementDxe: Fix exception
> 
> Great fix.
> I am wondering why this bug was not found earlier.
> If Status is 0 (Success), #PF exception would occur when NULL pointer protection is turned on.
> If Status is 0x80000000_x (Error), #GP exception would occur because an address with only the BIT63 set is an
> invalid address.
> 
> Thanks,
> Ray
> 
> > -----Original Message-----
> > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Darbin
> > Reyes
> > Sent: Wednesday, March 8, 2023 7:04 AM
> > To: devel@edk2.groups.io
> > Cc: Reyes, Darbin <darbin.reyes@intel.com>; Narey, Jacob
> > <jacob.narey@intel.com>
> > Subject: [edk2-devel] [PATCH] UefiCpuPkg/MicrocodeMeasurementDxe: Fix
> > exception
> >
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4360
> >
> > An incorrect format specifier is being used in a DEBUG print,
> > specifically, a variable of type EFI_STATUS was being printed with
> > the %a format specifier (pointer to an ASCII string), thus the value of
> > the Status variable was being treated as the address of a string,
> > leading to a CPU exception, when encountered this bug manifests itself
> > as a hang near "Ready to Boot Event", with the last DEBUG print being
> > "INFO: Got MicrocodePatchHob with microcode patches starting address"
> > followed by a CPU Exception dump.
> >
> > Signed-off-by: Darbin Reyes <darbin.reyes@intel.com>
> > Reviewed-by: Jacob Narey <jacob.narey@intel.com>
> > ---
> >  UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c |
> > 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git
> > a/UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c
> > b/UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c
> > index 762ca159ff..5fd3b3365c 100644
> > ---
> > a/UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c
> > +++
> > b/UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c
> > @@ -238,7 +238,7 @@ MeasureMicrocodePatches (
> >         TotalMicrocodeSize)
> >
> >        );
> >
> >    } else {
> >
> > -    DEBUG ((DEBUG_ERROR, "ERROR: TpmMeasureAndLogData failed with
> > status %a!\n", Status));
> >
> > +    DEBUG ((DEBUG_ERROR, "ERROR: TpmMeasureAndLogData failed with
> > status %r!\n", Status));
> >
> >    }
> >
> >
> >
> >    FreePool (Offsets);
> >
> > --
> > 2.38.1.windows.1
> >
> >
> >
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> 
> 
> 
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