Re: [PATCH v3] StandaloneMmPkg/Library: Install Variable Arch Protocol

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

(add StandaloneMmPkg maintainers)

On Mon, 4 Mar 2019 at 09:54, Jagadeesh Ujja <jagadeesh.ujja@arm.com> wrote:
>
> In a system implementing the variable store in MM, there are no variable
> arch protocol and variable write arch protocol installed into the
> DXE_SMM protocol database. On such systems, it is not required to
> locate these protocols by the DXE runtime variable drivers because
> it can be assumed that these protocols are already installed in the
> MM context. But then such an implementation will deviate from the
> existing traditional MM based variable driver implementation.
>
> So in order to maintain consistency with the traditional MM variable
> driver implementation, allow platforms to install these protocols into
> the DXE protocol database but these protocol will not be consumed
> by non-secure variable service runtime driver.
>
> The Platform which uses StandaloneMM based secure variable storage
> have to include this library
>
> Example
> In edk2-platforms/Platform/ARM/SgiPkg/SgiPlatform.dsc
>
>   ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.inf {
>     <LibraryClasses>
>       NULL|StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.inf
>   }
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jagadeesh Ujja <jagadeesh.ujja@arm.com>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---
> Changes since v2:
> - Addressed the comments from Ard Biesheuvel and Zeng Star
>
> Changes since v1:
> - This is a next version of patch
>    “MdeModulePkg/VariableSmmRuntimeDxe: Refactor locating Variable Arch Protocol”.
>    [https://lists.01.org/pipermail/edk2-devel/2019-February/036885.html]
> - Addressed the comments from Ard Biesheuvel and Zeng Star
> - Can this library be placed in MdePkg rather then the StandaloneMmPkg?
>
>  StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.c   | 54 ++++++++++++++++++++
>  StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.inf | 46 +++++++++++++++++
>  2 files changed, 100 insertions(+)
>
> diff --git a/StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.c b/StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.c
> new file mode 100644
> index 0000000..7e0f31b
> --- /dev/null
> +++ b/StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.c
> @@ -0,0 +1,54 @@
> +/** @file
> +  Runtime DXE part corresponding to StanaloneMM variable module.
> +
> +This module installs variable arch protocol and variable write arch protocol
> +to StandaloneMM runtime variable service.
> +
> +Copyright (c) 2019, ARM Ltd. All rights reserved.
> +
> +This program and the accompanying materials
> +are licensed and made available under the terms and conditions of the BSD License
> +which accompanies this distribution.  The full text of the license may be found at
> +http://opensource.org/licenses/bsd-license.php.
> +
> +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include <Library/DebugLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +
> +/**
> +  The constructor function installs variable arch protocol and variable
> +  write arch protocol to StandaloneMM runtime variable service
> +
> +  @param  ImageHandle   The firmware allocated handle for the EFI image.
> +  @param  SystemTable   A pointer to the Management mode System Table.
> +
> +  @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableMmDependencyLibConstructor (
> +  IN EFI_HANDLE                           ImageHandle,
> +  IN EFI_SYSTEM_TABLE                     *SystemTable
> +  )
> +{
> +  EFI_STATUS            Status;
> +  EFI_HANDLE            Handle;
> +
> +  Handle = NULL;
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &Handle,
> +                  &gEfiSmmVariableProtocolGuid,
> +                  NULL,
> +                  &gSmmVariableWriteGuid,
> +                  NULL,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +  return EFI_SUCCESS;
> +}
> +
> diff --git a/StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.inf b/StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.inf
> new file mode 100644
> index 0000000..e71c44d
> --- /dev/null
> +++ b/StandaloneMmPkg/Library/VariableMmDependency/VariableMmDependency.inf
> @@ -0,0 +1,46 @@
> +## @file
> +#  Runtime DXE part corresponding to StanaloneMM variable module.
> +#
> +#  This module installs variable arch protocol and variable write arch protocol
> +#  to StandaloneMM runtime variable service.
> +#
> +# Copyright (c) 2019, ARM Ltd. All rights reserved.
> +# This program and the accompanying materials
> +# are licensed and made available under the terms and conditions of the BSD License
> +# which accompanies this distribution. The full text of the license may be found at
> +# http://opensource.org/licenses/bsd-license.php
> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001A
> +  BASE_NAME                      = VariableMmDependency
> +  FILE_GUID                      = 64BC4129-778E-4867-BA07-13999A4DEC3F
> +  MODULE_TYPE                    = DXE_DRIVER
> +  LIBRARY_CLASS                  = NULL
> +  CONSTRUCTOR                    = VariableMmDependencyLibConstructor
> +
> +#
> +# The following information is for reference only and not required by the build tools.
> +#
> +#  VALID_ARCHITECTURES           = AARCH64
> +#
> +#
> +
> +[Sources]
> +  VariableMmDependency.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[Protocols]
> +  gEfiSmmVariableProtocolGuid        ## PRODUCES
> +
> +[Guids]
> +  gSmmVariableWriteGuid              ## PRODUCES             ## GUID # Install protocol
> +
> +[Depex]
> +  TRUE
> --
> 2.7.4
>