Re: [PATCH v1 2/5] MdeModulePkg/FaultTolerantWrite: Update to consume SpeculationBarrier

["Wang, Jian J" <jian.j.wang@intel.com>]

Reviewed-by: Jian J Wang <jian.j.wang@intel.com>


> -----Original Message-----
> From: Wu, Hao A
> Sent: Friday, December 21, 2018 11:11 AM
> To: edk2-devel@lists.01.org
> Cc: Wu, Hao A <hao.a.wu@intel.com>; Ard Biesheuvel
> <ard.biesheuvel@linaro.org>; Yao, Jiewen <jiewen.yao@intel.com>; Gao,
> Liming <liming.gao@intel.com>; Wang, Jian J <jian.j.wang@intel.com>
> Subject: [PATCH v1 2/5] MdeModulePkg/FaultTolerantWrite: Update to
> consume SpeculationBarrier
> 
> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1417
> 
> Since BaseLib API AsmLfence() is a x86 arch specific API and should be
> avoided using in generic codes, this commit replaces the usage of
> AsmLfence() with arch-generic API SpeculationBarrier().
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Hao Wu <hao.a.wu@intel.com>
> ---
>  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c | 8
> ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git
> a/MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c
> b/MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c
> index 27fcab19b6..481fea3f1f 100644
> ---
> a/MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c
> +++
> b/MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c
> @@ -419,11 +419,11 @@ SmmFaultTolerantWriteHandler (
>                   );
>        if (!EFI_ERROR (Status)) {
>          //
> -        // The AsmLfence() call here is to ensure the previous range/content
> -        // checks for the CommBuffer have been completed before calling into
> -        // FtwWrite().
> +        // The SpeculationBarrier() call here is to ensure the previous
> +        // range/content checks for the CommBuffer have been completed before
> +        // calling into FtwWrite().
>          //
> -        AsmLfence ();
> +        SpeculationBarrier ();
>          Status = FtwWrite(
>                     &mFtwDevice->FtwInstance,
>                     SmmFtwWriteHeader->Lba,
> --
> 2.12.0.windows.1