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

[Jagadeesh Ujja <jagadeesh.ujja@arm.com>]

hi Jiewen, Achin

On Mon, Mar 4, 2019 at 4:16 PM Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
> (add StandaloneMmPkg maintainers)
>
Please let me know if you have any comments on this patch

> 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
> >
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