Re: [Patch v3 1/6] UefiCpuPkg/RegisterCpuFeaturesLib: Add "Test Then Write" Macros.

["Dong, Eric" <eric.dong@intel.com>]

> -----Original Message-----
> From: Zeng, Star
> Sent: Friday, August 16, 2019 9:15 AM
> To: Dong, Eric <eric.dong@intel.com>; devel@edk2.groups.io
> Cc: Ni, Ray <ray.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>; Zeng,
> Star <star.zeng@intel.com>
> Subject: RE: [Patch v3 1/6] UefiCpuPkg/RegisterCpuFeaturesLib: Add "Test
> Then Write" Macros.
> 
> 
> 
> > -----Original Message-----
> > From: Dong, Eric
> > Sent: Thursday, August 15, 2019 10:51 AM
> > To: devel@edk2.groups.io
> > Cc: Ni, Ray <ray.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>;
> > Zeng, Star <star.zeng@intel.com>
> > Subject: [Patch v3 1/6] UefiCpuPkg/RegisterCpuFeaturesLib: Add "Test
> > Then Write" Macros.
> >
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2040
> >
> > Add below new micros which test the current value before write the new
> > value. Only write new value when current value not same as new value.
> >   CPU_REGISTER_TABLE_TEST_THEN_WRITE32
> >   CPU_REGISTER_TABLE_TEST_THEN_WRITE64
> >   CPU_REGISTER_TABLE_TEST_THEN_WRITE_FIELD
> >
> > Also add below API:
> >   CpuRegisterTableTestThenWrite
> >
> > Signed-off-by: Eric Dong <eric.dong@intel.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Star Zeng <star.zeng@intel.com>
> > ---
> >  UefiCpuPkg/Include/AcpiCpuData.h              |  1 +
> >  .../Include/Library/RegisterCpuFeaturesLib.h  | 91 +++++++++++++++++++
> >  .../RegisterCpuFeaturesLib.c                  | 45 ++++++++-
> >  3 files changed, 134 insertions(+), 3 deletions(-)
> >
> > diff --git a/UefiCpuPkg/Include/AcpiCpuData.h
> > b/UefiCpuPkg/Include/AcpiCpuData.h
> > index b963a2f592..472a1a8070 100644
> > --- a/UefiCpuPkg/Include/AcpiCpuData.h
> > +++ b/UefiCpuPkg/Include/AcpiCpuData.h
> > @@ -81,6 +81,7 @@ typedef struct {
> >    UINT16         Reserved;              // offset 10 - 11
> >    UINT32         HighIndex;             // offset 12-15, only valid for MemoryMapped
> >    UINT64         Value;                 // offset 16-23
> > +  UINT8          TestThenWrite;           // 0ffset 24
> 
> Could we use one byte of the Reserved field, but not add new field? And use
> BOOLEAN type for it?

I'm not sure whether use the Reserved field is an correct approach, do you have samples which use the reserved fields?
But I think add new field is a more safe one.

Thanks,
Eric
> 
> Thanks,
> Star
> 
> >  } CPU_REGISTER_TABLE_ENTRY;
> >
> >  //
> > diff --git a/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
> > b/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
> > index e420e7f075..5bd464b32e 100644
> > --- a/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
> > +++ b/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
> > @@ -348,6 +348,32 @@ CpuRegisterTableWrite (
> >    IN UINT64              Value
> >    );
> >
> > +/**
> > +  Adds an entry in specified register table.
> > +
> > +  This function adds an entry in specified register table, with given
> > + register type,  register index, bit section and value.
> > +
> > +  Driver will  test the current value before setting new value.
> > +
> > +  @param[in]  ProcessorNumber  The index of the CPU to add a register
> > table entry
> > +  @param[in]  RegisterType     Type of the register to program
> > +  @param[in]  Index            Index of the register to program
> > +  @param[in]  ValueMask        Mask of bits in register to write
> > +  @param[in]  Value            Value to write
> > +
> > +  @note This service could be called by BSP only.
> > +**/
> > +VOID
> > +EFIAPI
> > +CpuRegisterTableTestThenWrite (
> > +  IN UINTN               ProcessorNumber,
> > +  IN REGISTER_TYPE       RegisterType,
> > +  IN UINT64              Index,
> > +  IN UINT64              ValueMask,
> > +  IN UINT64              Value
> > +  );
> > +
> >  /**
> >    Adds an entry in specified Pre-SMM register table.
> >
> > @@ -390,6 +416,26 @@ PreSmmCpuRegisterTableWrite (
> >      CpuRegisterTableWrite (ProcessorNumber, RegisterType, Index,
> > MAX_UINT32, Value);  \
> >    } while(FALSE);
> >
> > +/**
> > +  Adds a 32-bit register write entry in specified register table.
> > +
> > +  This macro adds an entry in specified register table, with given
> > + register type,  register index, and value.
> > +
> > +  Driver will  test the current value before setting new value.
> > +
> > +  @param[in]  ProcessorNumber  The index of the CPU to add a register
> > table entry.
> > +  @param[in]  RegisterType     Type of the register to program
> > +  @param[in]  Index            Index of the register to program
> > +  @param[in]  Value            Value to write
> > +
> > +  @note This service could be called by BSP only.
> > +**/
> > +#define CPU_REGISTER_TABLE_TEST_THEN_WRITE32(ProcessorNumber,
> > RegisterType, Index, Value)     \
> > +  do {                                                                                        \
> > +    CpuRegisterTableTestThenWrite (ProcessorNumber, RegisterType,
> > +Index, MAX_UINT32, Value);  \
> > +  } while(FALSE);
> > +
> >  /**
> >    Adds a 64-bit register write entry in specified register table.
> >
> > @@ -408,6 +454,26 @@ PreSmmCpuRegisterTableWrite (
> >      CpuRegisterTableWrite (ProcessorNumber, RegisterType, Index,
> > MAX_UINT64, Value);  \
> >    } while(FALSE);
> >
> > +/**
> > +  Adds a 64-bit register write entry in specified register table.
> > +
> > +  This macro adds an entry in specified register table, with given
> > + register type,  register index, and value.
> > +
> > +  Driver will  test the current value before setting new value.
> > +
> > +  @param[in]  ProcessorNumber  The index of the CPU to add a register
> > table entry.
> > +  @param[in]  RegisterType     Type of the register to program
> > +  @param[in]  Index            Index of the register to program
> > +  @param[in]  Value            Value to write
> > +
> > +  @note This service could be called by BSP only.
> > +**/
> > +#define CPU_REGISTER_TABLE_TEST_THEN_WRITE64(ProcessorNumber,
> > RegisterType, Index, Value)     \
> > +  do {                                                                                        \
> > +    CpuRegisterTableTestThenWrite (ProcessorNumber, RegisterType,
> > +Index, MAX_UINT64, Value);  \
> > +  } while(FALSE);
> > +
> >  /**
> >    Adds a bit field write entry in specified register table.
> >
> > @@ -431,6 +497,31 @@ PreSmmCpuRegisterTableWrite (
> >      CpuRegisterTableWrite (ProcessorNumber, RegisterType, Index,
> > ~ValueMask, Value);             \
> >    } while(FALSE);
> >
> > +/**
> > +  Adds a bit field write entry in specified register table.
> > +
> > +  This macro adds an entry in specified register table, with given
> > + register type,  register index, bit field section, and value.
> > +
> > +  Driver will  test the current value before setting new value.
> > +
> > +  @param[in]  ProcessorNumber  The index of the CPU to add a register
> > table entry.
> > +  @param[in]  RegisterType     Type of the register to program.
> > +  @param[in]  Index            Index of the register to program.
> > +  @param[in]  Type             The data type name of a register structure.
> > +  @param[in]  Field            The bit fiel name in register structure to write.
> > +  @param[in]  Value            Value to write to the bit field.
> > +
> > +  @note This service could be called by BSP only.
> > +**/
> > +#define
> > CPU_REGISTER_TABLE_TEST_THEN_WRITE_FIELD(ProcessorNumber,
> > RegisterType, Index, Type, Field, Value) \
> > +  do {                                                                                                     \
> > +    UINT64  ValueMask;                                                                                     \
> > +    ValueMask = MAX_UINT64;                                                                                \
> > +    ((Type *)(&ValueMask))->Field = 0;                                                                     \
> > +    CpuRegisterTableTestThenWrite (ProcessorNumber, RegisterType,
> > + Index,
> > ~ValueMask, Value);               \
> > +  } while(FALSE);
> > +
> >  /**
> >    Adds a 32-bit register write entry in specified register table.
> >
> > diff --git
> > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> > index 67885bf69b..e9769882b9 100644
> > ---
> > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> > +++
> > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> > @@ -1025,6 +1025,8 @@ EnlargeRegisterTable (
> >    @param[in]  ValidBitStart    Start of the bit section
> >    @param[in]  ValidBitLength   Length of the bit section
> >    @param[in]  Value            Value to write
> > +  @param[in]  TestThenWrite    Whether need to test current Value before
> > writing.
> > +
> >  **/
> >  VOID
> >  CpuRegisterTableWriteWorker (
> > @@ -1034,7 +1036,8 @@ CpuRegisterTableWriteWorker (
> >    IN UINT64                  Index,
> >    IN UINT8                   ValidBitStart,
> >    IN UINT8                   ValidBitLength,
> > -  IN UINT64                  Value
> > +  IN UINT64                  Value,
> > +  IN UINT8                   TestThenWrite
> >    )
> >  {
> >    CPU_FEATURES_DATA        *CpuFeaturesData;
> > @@ -1070,6 +1073,7 @@ CpuRegisterTableWriteWorker (
> >    RegisterTableEntry[RegisterTable->TableLength].ValidBitStart  =
> > ValidBitStart;
> >    RegisterTableEntry[RegisterTable->TableLength].ValidBitLength =
> > ValidBitLength;
> >    RegisterTableEntry[RegisterTable->TableLength].Value          = Value;
> > +  RegisterTableEntry[RegisterTable->TableLength].TestThenWrite  =
> > + TestThenWrite;
> >
> >    RegisterTable->TableLength++;
> >  }
> > @@ -1105,7 +1109,42 @@ CpuRegisterTableWrite (
> >    Start  = (UINT8)LowBitSet64  (ValueMask);
> >    End    = (UINT8)HighBitSet64 (ValueMask);
> >    Length = End - Start + 1;
> > -  CpuRegisterTableWriteWorker (FALSE, ProcessorNumber, RegisterType,
> > Index, Start, Length, Value);
> > +  CpuRegisterTableWriteWorker (FALSE, ProcessorNumber, RegisterType,
> > +Index, Start, Length, Value, FALSE); }
> > +
> > +/**
> > +  Adds an entry in specified register table.
> > +
> > +  This function adds an entry in specified register table, with given
> > + register type,  register index, bit section and value.
> > +
> > +  @param[in]  ProcessorNumber  The index of the CPU to add a register
> > table entry
> > +  @param[in]  RegisterType     Type of the register to program
> > +  @param[in]  Index            Index of the register to program
> > +  @param[in]  ValueMask        Mask of bits in register to write
> > +  @param[in]  Value            Value to write
> > +  @param[in]  TestThenWrite    Whether need to test current Value before
> > writing.
> > +
> > +  @note This service could be called by BSP only.
> > +**/
> > +VOID
> > +EFIAPI
> > +CpuRegisterTableTestThenWrite (
> > +  IN UINTN               ProcessorNumber,
> > +  IN REGISTER_TYPE       RegisterType,
> > +  IN UINT64              Index,
> > +  IN UINT64              ValueMask,
> > +  IN UINT64              Value
> > +  )
> > +{
> > +  UINT8                   Start;
> > +  UINT8                   End;
> > +  UINT8                   Length;
> > +
> > +  Start  = (UINT8)LowBitSet64  (ValueMask);
> > +  End    = (UINT8)HighBitSet64 (ValueMask);
> > +  Length = End - Start + 1;
> > +  CpuRegisterTableWriteWorker (FALSE, ProcessorNumber, RegisterType,
> > + Index, Start, Length, Value, TRUE);
> >  }
> >
> >  /**
> > @@ -1139,7 +1178,7 @@ PreSmmCpuRegisterTableWrite (
> >    Start  = (UINT8)LowBitSet64  (ValueMask);
> >    End    = (UINT8)HighBitSet64 (ValueMask);
> >    Length = End - Start + 1;
> > -  CpuRegisterTableWriteWorker (TRUE, ProcessorNumber, RegisterType,
> > Index, Start, Length, Value);
> > +  CpuRegisterTableWriteWorker (TRUE, ProcessorNumber, RegisterType,
> > + Index, Start, Length, Value, FALSE);
> >  }
> >
> >  /**
> > --
> > 2.21.0.windows.1