Re: [Patch v3 1/3] UefiCpuPkg/MpInitLib: Relocate uCode to memory to save time.

["Ni, Ruiyu" <ruiyu.ni@Intel.com>]

On 7/16/2018 11:08 AM, Eric Dong wrote:
> Read uCode from memory has better performance than from flash.
> But it needs extra effort to let BSP copy uCode from flash to
> memory. Also BSP already enable cache in SEC phase, so it use
> less time to relocate uCode from flash to memory. After
> verification, if system has more than one processor, it will
> reduce some time if load uCode from memory.
> 
> This change enable this optimization.
> 
> V3 changes:
>    Remove the ASSERT which is not correct.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> ---
>   UefiCpuPkg/Library/MpInitLib/MpLib.c | 33 ++++++++++++++++++++++++++++++++-
>   1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> index 108eea0a6f..d8b56f149f 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> @@ -1520,6 +1520,7 @@ MpInitLibInitialize (
>     UINTN                    ApResetVectorSize;
>     UINTN                    BackupBufferAddr;
>     UINTN                    ApIdtBase;
> +  VOID                     *MicrocodePatchInRam;
>   
>     OldCpuMpData = GetCpuMpDataFromGuidedHob ();
>     if (OldCpuMpData == NULL) {
> @@ -1587,8 +1588,38 @@ MpInitLibInitialize (
>     CpuMpData->SwitchBspFlag    = FALSE;
>     CpuMpData->CpuData          = (CPU_AP_DATA *) (CpuMpData + 1);
>     CpuMpData->CpuInfoInHob     = (UINT64) (UINTN) (CpuMpData->CpuData + MaxLogicalProcessorNumber);
> -  CpuMpData->MicrocodePatchAddress    = PcdGet64 (PcdCpuMicrocodePatchAddress);
>     CpuMpData->MicrocodePatchRegionSize = PcdGet64 (PcdCpuMicrocodePatchRegionSize);
> +  //
> +  // If platform has more than one CPU, relocate microcode to memory to reduce
> +  // loading microcode time.
> +  //
> +  MicrocodePatchInRam = NULL;
> +  if (MaxLogicalProcessorNumber > 1) {
> +    MicrocodePatchInRam = AllocatePages (
> +                            EFI_SIZE_TO_PAGES (
> +                              (UINTN)CpuMpData->MicrocodePatchRegionSize
> +                              )
> +                            );
> +  }
> +  if (MicrocodePatchInRam == NULL) {
> +    //
> +    // there is only one processor, or no microcode patch is available, or
> +    // memory allocation failed
> +    //
> +    CpuMpData->MicrocodePatchAddress = PcdGet64 (PcdCpuMicrocodePatchAddress);
> +  } else {
> +    //
> +    // there are multiple processors, and a microcode patch is available, and
> +    // memory allocation succeeded
> +    //
> +    CopyMem (
> +      MicrocodePatchInRam,
> +      (VOID *)(UINTN)PcdGet64 (PcdCpuMicrocodePatchAddress),
> +      (UINTN)CpuMpData->MicrocodePatchRegionSize
> +      );
> +    CpuMpData->MicrocodePatchAddress = (UINTN)MicrocodePatchInRam;
> +  }
> +
>     InitializeSpinLock(&CpuMpData->MpLock);
>   
>     //
> 
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

-- 
Thanks,
Ray