Re: [PATCH] UefiCpuPkg CpuCommonFeaturesLib: Enhance Ppin code

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

Hi Star,

Suggest to add some code comments for the behavior, detail see the inline comments.
with these comments, Reviewed-by: Eric Dong <eric.dong@intel.com>

Thanks,
Eric
> -----Original Message-----
> From: Zeng, Star
> Sent: Friday, July 12, 2019 6:13 PM
> To: devel@edk2.groups.io
> Cc: Zeng, Star <star.zeng@intel.com>; Laszlo Ersek <lersek@redhat.com>;
> Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar,
> Chandana C <chandana.c.kumar@intel.com>; Li, Kevin Y
> <kevin.y.li@intel.com>
> Subject: [PATCH] UefiCpuPkg CpuCommonFeaturesLib: Enhance Ppin code
> 
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1961
> Enhance Ppin code to enable and unlock for TRUE State, and disable and lock
> for FALSE State.
> Note: enable and lock could not be set both.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Chandana Kumar <chandana.c.kumar@intel.com>
> Cc: Kevin Li <kevin.y.li@intel.com>
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> ---
>  .../CpuCommonFeaturesLib/CpuCommonFeatures.h  | 15 +++++
>  .../CpuCommonFeaturesLib.c                    |  2 +-
>  .../Library/CpuCommonFeaturesLib/Ppin.c       | 65 +++++++++++++++----
>  3 files changed, 70 insertions(+), 12 deletions(-)
> 
> diff --git
> a/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeatures.h
> b/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeatures.h
> index 9e784e916a85..8406c6c1619f 100644
> --- a/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeatures.h
> +++ b/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeatures.h
> @@ -863,6 +863,21 @@ FeatureControlGetConfigData (
>    IN UINTN               NumberOfProcessors
>    );
> 
> +/**
> +  Prepares for the data used by CPU feature detection and initialization.
> +
> +  @param[in]  NumberOfProcessors  The number of CPUs in the platform.
> +
> +  @return  Pointer to a buffer of CPU related configuration data.
> +
> +  @note This service could be called by BSP only.
> +**/
> +VOID *
> +EFIAPI
> +PpinGetConfigData (
> +  IN UINTN               NumberOfProcessors
> +  );
> +
>  /**
>    Detects if Protected Processor Inventory Number feature supported on
> current
>    processor.
> diff --git
> a/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeaturesLib.c
> b/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeaturesLib.c
> index 7cc692efb649..fd43b8d66290 100644
> ---
> a/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeaturesLib.c
> +++
> b/UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeaturesLib.c
> @@ -203,7 +203,7 @@ CpuCommonFeaturesLibConstructor (
>    if (IsCpuFeatureSupported (CPU_FEATURE_PPIN)) {
>      Status = RegisterCpuFeature (
>                 "PPIN",
> -               NULL,
> +               PpinGetConfigData,
>                 PpinSupport,
>                 PpinInitialize,
>                 CPU_FEATURE_PPIN,
> diff --git a/UefiCpuPkg/Library/CpuCommonFeaturesLib/Ppin.c
> b/UefiCpuPkg/Library/CpuCommonFeaturesLib/Ppin.c
> index e8a4de8dcf60..8067cf44d015 100644
> --- a/UefiCpuPkg/Library/CpuCommonFeaturesLib/Ppin.c
> +++ b/UefiCpuPkg/Library/CpuCommonFeaturesLib/Ppin.c
> @@ -8,6 +8,28 @@
> 
>  #include "CpuCommonFeatures.h"
> 
> +/**
> +  Prepares for the data used by CPU feature detection and initialization.
> +
> +  @param[in]  NumberOfProcessors  The number of CPUs in the platform.
> +
> +  @return  Pointer to a buffer of CPU related configuration data.
> +
> +  @note This service could be called by BSP only.
> +**/
> +VOID *
> +EFIAPI
> +PpinGetConfigData (
> +  IN UINTN               NumberOfProcessors
> +  )
> +{
> +  VOID          *ConfigData;
> +
> +  ConfigData = AllocateZeroPool (sizeof
> +(MSR_IVY_BRIDGE_PPIN_CTL_REGISTER) * NumberOfProcessors);
> +  ASSERT (ConfigData != NULL);
> +  return ConfigData;
> +}
> +
>  /**
>    Detects if Protected Processor Inventory Number feature supported on
> current
>    processor.
> @@ -34,6 +56,7 @@ PpinSupport (
>    )
>  {
>    MSR_IVY_BRIDGE_PLATFORM_INFO_1_REGISTER    PlatformInfo;
> +  MSR_IVY_BRIDGE_PPIN_CTL_REGISTER           *MsrPpinCtrl;
> 
>    if ((CpuInfo->DisplayFamily == 0x06) &&
>        ((CpuInfo->DisplayModel == 0x3E) ||      // Xeon E5 V2
> @@ -47,7 +70,12 @@ PpinSupport (
>      // Check whether platform support this feature.
>      //
>      PlatformInfo.Uint64 = AsmReadMsr64
> (MSR_IVY_BRIDGE_PLATFORM_INFO_1);
> -    return (PlatformInfo.Bits.PPIN_CAP != 0);
> +    if (PlatformInfo.Bits.PPIN_CAP != 0) {
> +      MsrPpinCtrl = (MSR_IVY_BRIDGE_PPIN_CTL_REGISTER *) ConfigData;
> +      ASSERT (MsrPpinCtrl != NULL);
> +      MsrPpinCtrl[ProcessorNumber].Uint64 = AsmReadMsr64
> (MSR_IVY_BRIDGE_PPIN_CTL);
> +      return TRUE;
> +    }
>    }
> 
>    return FALSE;
> @@ -73,6 +101,7 @@ PpinSupport (
>    @retval RETURN_DEVICE_ERROR  Device can't change state because it has
> been
>                                 locked.
> 
> +  @note This service could be called by BSP only.
>  **/
>  RETURN_STATUS
>  EFIAPI
> @@ -83,16 +112,18 @@ PpinInitialize (
>    IN BOOLEAN                           State
>    )
>  {
> -  MSR_IVY_BRIDGE_PPIN_CTL_REGISTER     MsrPpinCtrl;
> +  MSR_IVY_BRIDGE_PPIN_CTL_REGISTER     *MsrPpinCtrl;
> +
> +  MsrPpinCtrl = (MSR_IVY_BRIDGE_PPIN_CTL_REGISTER *) ConfigData;
> + ASSERT (MsrPpinCtrl != NULL);
> 
>    //
> -  // Check whether device already lock this register.
> -  // If already locked, just base on the request state and
> +  // Check whether processor already lock this register.
> +  // If already locked, just based on the request state and
>    // the current state to return the status.
>    //
> -  MsrPpinCtrl.Uint64 = AsmReadMsr64 (MSR_IVY_BRIDGE_PPIN_CTL);
> -  if (MsrPpinCtrl.Bits.LockOut != 0) {
> -    return MsrPpinCtrl.Bits.Enable_PPIN == State ? RETURN_SUCCESS :
> RETURN_DEVICE_ERROR;
> +  if (MsrPpinCtrl[ProcessorNumber].Bits.LockOut != 0) {
> +    return MsrPpinCtrl[ProcessorNumber].Bits.Enable_PPIN == State ?
> + RETURN_SUCCESS : RETURN_DEVICE_ERROR;
>    }
> 
>    //
> @@ -106,13 +137,25 @@ PpinInitialize (
>      return RETURN_SUCCESS;
>    }
> 
> -  CPU_REGISTER_TABLE_WRITE_FIELD (
> +  if (State) {
> +    //
> +    // Enable and Unlock.
> +    //
> +    MsrPpinCtrl[ProcessorNumber].Bits.Enable_PPIN = 1;
> +    MsrPpinCtrl[ProcessorNumber].Bits.LockOut = 0;  } else {
 
1. I suggest to add some comments about why unlock & enable need to set at the same time.


> +    //
> +    // Disable and Lock.
> +    //
> +    MsrPpinCtrl[ProcessorNumber].Bits.Enable_PPIN = 0;
> +    MsrPpinCtrl[ProcessorNumber].Bits.LockOut = 1;  }


2. Same as  comments 1.

Thanks,
Eric
> +
> +  CPU_REGISTER_TABLE_WRITE64 (
>      ProcessorNumber,
>      Msr,
>      MSR_IVY_BRIDGE_PPIN_CTL,
> -    MSR_IVY_BRIDGE_PPIN_CTL_REGISTER,
> -    Bits.Enable_PPIN,
> -    (State) ? 1 : 0
> +    MsrPpinCtrl[ProcessorNumber].Uint64
>      );
> 
>    return RETURN_SUCCESS;
> --
> 2.21.0.windows.1