Reviewed-by: Jian J Wang <[email protected]>
> -----Original Message-----
> From: Wu, Hao A
> Sent: Friday, December 21, 2018 11:11 AM
> To: [email protected]
> Cc: Wu, Hao A <[email protected]>; Ard Biesheuvel
> <[email protected]>; Yao, Jiewen <[email protected]>; Gao,
> Liming <[email protected]>; Wang, Jian J <[email protected]>; Zeng,
> Star <[email protected]>
> Subject: [PATCH v1 4/5] MdeModulePkg/Variable: 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().
>
> Please note that speculation execution barriers are intended to be
> asserted for SMM codes, hence, this commit still preserve an empty
> implementation of the speculation execution barrier for the DXE codes.
>
> Cc: Ard Biesheuvel <[email protected]>
> Cc: Jiewen Yao <[email protected]>
> Cc: Liming Gao <[email protected]>
> Cc: Jian J Wang <[email protected]>
> Cc: Star Zeng <[email protected]>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Hao Wu <[email protected]>
> ---
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> | 2 +-
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> | 2 +-
> MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
> | 10 ++++----
> MdeModulePkg/Universal/Variable/RuntimeDxe/{LoadFenceDxe.c =>
> SpeculationBarrierDxe.c} | 12 ++++++----
> MdeModulePkg/Universal/Variable/RuntimeDxe/{LoadFenceSmm.c =>
> SpeculationBarrierSmm.c} | 14 +++++++-----
> MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> |
> 6 ++---
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> | 24 ++++++++++----------
> 7 files changed, 38 insertions(+), 32 deletions(-)
>
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> index 868981ccaf..7ef8a97f5d 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> @@ -46,7 +46,7 @@
> TcgMorLockDxe.c
> VarCheck.c
> VariableExLib.c
> - LoadFenceDxe.c
> + SpeculationBarrierDxe.c
>
> [Packages]
> MdePkg/MdePkg.dec
> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> index 2fe72ff8a4..db7d220e06 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> @@ -54,7 +54,7 @@
> PrivilegePolymorphic.h
> VariableExLib.c
> TcgMorLockSmm.c
> - LoadFenceSmm.c
> + SpeculationBarrierSmm.c
>
> [Packages]
> MdePkg/MdePkg.dec
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
> index a324ad2365..7af22a4ad6 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
> @@ -85,13 +85,15 @@ SetVariableCheckHandlerMor (
> );
>
> /**
> - This service is consumed by the variable modules to perform a serializing
> - operation on all load-from-memory instructions that were issued prior to
> the
> - call of this function.
> + This service is consumed by the variable modules to place a barrier to stop
> + speculative execution.
> +
> + Ensures that no later instruction will execute speculatively, until all
> prior
> + instructions have completed.
>
> **/
> VOID
> -MemoryLoadFence (
> +VariableSpeculationBarrier (
> VOID
> );
>
> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierDxe.c
> similarity index 62%
> rename from MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c
> rename to
> MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierDxe.c
> index 0f64ee093b..bc3f695335 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierDxe.c
> @@ -1,5 +1,5 @@
> /** @file
> - Serialize operation on all load-from-memory instructions (DXE version).
> + Barrier to stop speculative execution (DXE version).
>
> Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
> This program and the accompanying materials
> @@ -15,13 +15,15 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
> #include "Variable.h"
>
> /**
> - This service is consumed by the variable modules to perform a serializing
> - operation on all load-from-memory instructions that were issued prior to
> the
> - call of this function.
> + This service is consumed by the variable modules to place a barrier to stop
> + speculative execution.
> +
> + Ensures that no later instruction will execute speculatively, until all
> prior
> + instructions have completed.
>
> **/
> VOID
> -MemoryLoadFence (
> +VariableSpeculationBarrier (
> VOID
> )
> {
> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierSmm.c
> similarity index 61%
> rename from MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c
> rename to
> MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierSmm.c
> index 4b0d7e3e95..dbc20f6c4d 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c
> +++
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierSmm.c
> @@ -1,5 +1,5 @@
> /** @file
> - Serialize operation on all load-from-memory instructions (SMM version).
> + Barrier to stop speculative execution (SMM version).
>
> Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
> This program and the accompanying materials
> @@ -16,15 +16,17 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
> #include "Variable.h"
>
> /**
> - This service is consumed by the variable modules to perform a serializing
> - operation on all load-from-memory instructions that were issued prior to
> the
> - call of this function.
> + This service is consumed by the variable modules to place a barrier to stop
> + speculative execution.
> +
> + Ensures that no later instruction will execute speculatively, until all
> prior
> + instructions have completed.
>
> **/
> VOID
> -MemoryLoadFence (
> +VariableSpeculationBarrier (
> VOID
> )
> {
> - AsmLfence ();
> + SpeculationBarrier ();
> }
> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> index d100b1dcc5..443cf07144 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> @@ -3201,11 +3201,11 @@ VariableServiceSetVariable (
> return EFI_SECURITY_VIOLATION;
> }
> //
> - // The MemoryLoadFence() call here is to ensure the above sanity check
> - // for the EFI_VARIABLE_AUTHENTICATION_2 descriptor has been completed
> + // The VariableSpeculationBarrier() call here is to ensure the above
> sanity
> + // check for the EFI_VARIABLE_AUTHENTICATION_2 descriptor has been
> completed
> // before the execution of subsequent codes.
> //
> - MemoryLoadFence ();
> + VariableSpeculationBarrier ();
> PayloadSize = DataSize - AUTHINFO2_SIZE (Data);
> } else {
> PayloadSize = DataSize;
> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> index 6dc19c24db..8c53f84ff6 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> @@ -538,11 +538,11 @@ SmmVariableHandler (
> }
>
> //
> - // The MemoryLoadFence() call here is to ensure the previous
> range/content
> - // checks for the CommBuffer have been completed before the subsequent
> - // consumption of the CommBuffer content.
> + // The VariableSpeculationBarrier() call here is to ensure the previous
> + // range/content checks for the CommBuffer have been completed before
> the
> + // subsequent consumption of the CommBuffer content.
> //
> - MemoryLoadFence ();
> + VariableSpeculationBarrier ();
> if (SmmVariableHeader->NameSize < sizeof (CHAR16) ||
> SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) -
> 1] != L'\0') {
> //
> // Make sure VariableName is A Null-terminated string.
> @@ -638,11 +638,11 @@ SmmVariableHandler (
> }
>
> //
> - // The MemoryLoadFence() call here is to ensure the previous
> range/content
> - // checks for the CommBuffer have been completed before the subsequent
> - // consumption of the CommBuffer content.
> + // The VariableSpeculationBarrier() call here is to ensure the previous
> + // range/content checks for the CommBuffer have been completed before
> the
> + // subsequent consumption of the CommBuffer content.
> //
> - MemoryLoadFence ();
> + VariableSpeculationBarrier ();
> if (SmmVariableHeader->NameSize < sizeof (CHAR16) ||
> SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) -
> 1] != L'\0') {
> //
> // Make sure VariableName is A Null-terminated string.
> @@ -779,11 +779,11 @@ SmmVariableHandler (
> }
>
> //
> - // The MemoryLoadFence() call here is to ensure the previous
> range/content
> - // checks for the CommBuffer have been completed before the subsequent
> - // consumption of the CommBuffer content.
> + // The VariableSpeculationBarrier() call here is to ensure the previous
> + // range/content checks for the CommBuffer have been completed before
> the
> + // subsequent consumption of the CommBuffer content.
> //
> - MemoryLoadFence ();
> + VariableSpeculationBarrier ();
> if (CommVariableProperty->NameSize < sizeof (CHAR16) ||
> CommVariableProperty->Name[CommVariableProperty->NameSize/sizeof
> (CHAR16) - 1] != L'\0') {
> //
> // Make sure VariableName is A Null-terminated string.
> --
> 2.12.0.windows.1
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