Re: [RFC PATCH v4 00/12] Extend secure variable service to be usable from Standalone MM

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

Hi Liming

On Wed, Dec 12, 2018 at 8:44 PM Gao, Liming <liming.gao@intel.com> wrote:
>
> This version is better. I have some comments on edk2 coding style.

Thank you for your review. Please see reply to your comments below.

>
> 1. This patch set can't be applied in edk2 trunk. Seemly, they base on previous version edk2.

The v4 patchset was based on the tip of the edk2 master branch on the
day it was posted. The commit id on which this series was based is
"f7f94ffe".

> 2. Pcd is for Standalone MM Code, not specific for Variable. So, I suggest to use the generic name PcdStandaloneMmCodeEnabled. Its description is also required to be updated.

The intention of the changes done in the patchset is to reuse the
variable service driver in MM_STANDALONE mode. There could be
platforms that enable Standalone MM mode but would not want a  secure
storage for EFI variables. In which case, the PCD named
PcdStandaloneMmCodeEnabled would not be sufficient. And this the
reason it was named " PcdStandaloneMmVariableEnabled".

> 3. Library header file name (StandaloneMmServicesTableLib.h) is also library class name. Library class name and header file mapping is required to be listed in MdePkg.dec file [LibraryClasses] section. And, this header file doesn't need to include Library/DebugLib.h, because it doesn't depend on it.
> 4. Library implementation INF file (StandaloneMmRuntimeDxe.inf) should list its library class name in LIBRARY_CLASS of [Defines] section. Its library class name is StandaloneMmServicesTableLib. And, MdePkg library implementation depends on MdePkg.dec only in [Packages] section.
> 5. Library implementation should implement all interfaces defined in library class header file. StandaloneMmRuntimeDxe library should initialize gMmst as NULL if it has no real value. StandaloneMmRuntimeDxe library doesn't depend on any other library class. It doesn't need to list other library class in its [LibraryClasses] section of INF file.

Point 3, 4 and 5 will be fixed

> 6. When other module depends on this library class header file, it should list StandaloneMmServicesTableLib in its [LibraryClasses] section of INF file.
> 7. Platform DSC also needs to list LibraryClassName|Library implementation INF in [LibraryClasses] section.

Points 6 and 7 are taken care and are part of edk2platform specific
changes, will post those changes soon

> 8. I don't suggest to add AsmLfence API in BaseLib for AArch64, because it is X86 specific API. I suggest to update Variable driver with the wrapper function FenceFunc() for AsmLfence() and MemoryFence(). FenceFunc can be implemented for the different arch in Variable driver. Variable driver will call FenceFunc() instead of AsmLfence(). So, only variable driver is required to be updated. There is no change in BaseLib.
>
Okay, the variable driver can be updated to call a wrapper
"FenceFunc()" but wouldn't it be useful to add the architecture
specific implantation of this in BaseLib. In that way, not just the
variable driver but other drivers can use this implementation of
"FenceFunc()". For instance,
FaultTolerantWriteDxe/FaultTolerantWriteSmm.c does calls to
AsmLfence() and an architecture specific implementation of
"FenceFunc()" in BaseLib can be reused in FaultTolerantWriteDxe driver
as well.

> > -----Original Message-----
> > From: Jagadeesh Ujja [mailto:jagadeesh.ujja@arm.com]
> > Sent: Tuesday, December 11, 2018 2:22 PM
> > To: edk2-devel@lists.01.org; Gao, Liming <liming.gao@intel.com>; Zhang, Chao B <chao.b.zhang@intel.com>; leif.lindholm@linaro.org
> > Subject: [RFC PATCH v4 00/12] Extend secure variable service to be usable from Standalone MM
> >
> > Changes since v3:
> > - Addressed all the comments from Liming Gao
> >   - Added a AArch64 implementation of AsmLfence which is a wrapper for
> >     MemoryFence. The changes in variable service driver in v3 of this
> >     patchset that used MemoryFence instead of AsmLfence have been removed.
> >   - Added StandaloneMmServicesTableLib.h and StandaloneMmRuntimeDxe
> >     library into MdePkg.
> >   - Renamed PcdStandaloneMmEnable as PcdStandaloneMmVariableEnabled and
> >     added to in to MdePkg.
> >   - Now with above changes, edk2 packages don't need to depend on
> >     StandaloneMmPkg/StandaloneMmPkg.dec
> > - Addressed comments from Ting Ye
> >   - Removed the hacks in the v3 version.
> >   - Will relook into the “TimerWrapp.c” file and add a appropriate
> >     implementation of this for MM Standalone mode code.
> >
> > Changes since v2:
> > - Added 'Contributed-under' tag, removed Change-ID tag and
> >   maintained a single signed-off-by for the all the patches.
> >
> > Changes since v1:
> > - Addressed all the comments from Liming Gao
> >   - Removed the use of #ifdef/#else/#endif and used a Pcd instead to
> >     select between MM and non-MM paths.
> >   - Removed all dependencies on edk2-platforms.
> >   - Dropped the use of mMmst and used gSmst instead.
> >   - Added a dummy implementation UefiRuntimeServiceTableLib for
> >     MM_STANDALONE usage
> > - Replaced all uses of AsmLfence with MemoryFence from variable
> >   service code.
> > - Add a new StandaloneMmRuntimeDxe library to for use by non-MM code.
> >
> > This RFC patch series extends the existing secure variable service support for
> > use with Standalone MM. This is applicable to paltforms that use Standalone
> > Management Mode to protect access to non-volatile memory (NOR flash in case
> > of these patches) used to store the secure EFI variables.
> >
> > The first patch pulls in additional libraries from the staging branch of
> > StandaloneMmPkg into the edk2's StandaloneMmPkg. The existing secure variable
> > service implementation supports only the traditional MM mode and so the rest
> > of the patches extends the existing secure variable service support to be
> > useable with Standalone MM mode as well.
> >
> > This patch series is being posted as an RFC to get feedback on the approach taken
> > in these patches.
> >
> > Jagadeesh Ujja (12):
> >   StandaloneMmPkg: Pull in additonal libraries from staging branch
> >   MdePkg: Add a PCD to enable secure storage of variables
> >   MdePkg/Include: add StandaloneMmServicesTableLib header file
> >   MdePkg/Library/BaseLib/AArch64: Add AsmLfence function
> >   MdePkg/Library: Add StandaloneMmRuntimeDxe library
> >   MdeModulePkg/FaultTolerantWriteDxe: allow reusability as a MM driver
> >   MdeModulePkg/Variable/RuntimeDxe: adapt for usability with MM
> >     Standalone
> >   MdeModulePkg/Variable/RuntimeDxe: adapt as a MM Standalone driver
> >   MdeModulePkg/VarCheckLib: allow MM_STANDALONE drivers to use this
> >     library
> >   ArmPlatformPkg/NorFlashDxe: allow reusability as a MM driver
> >   SecurityPkg/AuthVariableLib: allow MM_STANDALONE drivers to use this
> >     library
> >   CryptoPkg/BaseCryptLib: allow MM_STANDALONE drivers to use this
> >     library
> >
> >  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashBlockIoDxe.c                                     |   2 +-
> >  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.c                                            | 210 ++++-
> >  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.h                                            |   4 +-
> >  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.inf                                          |   3 +
> >  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashFvbDxe.c                                         |  96 +--
> >  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashStandaloneMm.inf                                 |  76 ++
> >  CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf                                             |   7 +-
> >  CryptoPkg/Library/BaseCryptLib/RuntimeCryptLib.inf                                          |   4 +
> >  CryptoPkg/Library/BaseCryptLib/SysCall/TimerWrapper.c                                       |  15 +-
> >  MdeModulePkg/Library/VarCheckLib/VarCheckLib.inf                                            |   5 +-
> >  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteDxe.inf                      |   1 +
> >  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c                        | 203 +++--
> >  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteStandaloneMm.inf             | 101 +++
> >  MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c                           |  27 +-
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c                                       |  37 +-
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf                           |   1 +
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c                                    | 201 ++++-
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c                          |  31 +-
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf                        |   3 +
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.inf                         | 132 ++++
> >  MdePkg/Include/Library/BaseLib.h                                                            |  10 +
> >  MdePkg/Include/Library/StandaloneMmServicesTableLib.h                                       |  45 ++
> >  MdePkg/Library/BaseLib/AArch64/AsmLfence.S                                                  |  42 +
> >  MdePkg/Library/BaseLib/AArch64/AsmLfence.asm                                                |  41 +
> >  MdePkg/Library/BaseLib/BaseLib.inf                                                          |   2 +
> >  MdePkg/Library/StandaloneMmRuntimeDxe/StandaloneMmRuntimeDxe.c                              |  36 +
> >  MdePkg/Library/StandaloneMmRuntimeDxe/StandaloneMmRuntimeDxe.inf                            |  42 +
> >  MdePkg/MdePkg.dec                                                                           |   5 +
> >  SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf                                     |   5 +-
> >  StandaloneMmPkg/Library/StandaloneMmCoreHobLib/StandaloneMmCoreHobLib.inf                   |   2 +-
> >  StandaloneMmPkg/Library/StandaloneMmHobLib/AArch64/StandaloneMmCoreHobLibInternal.c         |  64 ++
> >  StandaloneMmPkg/Library/StandaloneMmHobLib/StandaloneMmHobLib.c                             | 655
> > ++++++++++++++++
> >  StandaloneMmPkg/Library/StandaloneMmHobLib/StandaloneMmHobLib.inf                           |  48 ++
> >  StandaloneMmPkg/Library/StandaloneMmMemoryAllocationLib/StandaloneMmMemoryAllocationLib.c   | 824
> > ++++++++++++++++++++
> >  StandaloneMmPkg/Library/StandaloneMmMemoryAllocationLib/StandaloneMmMemoryAllocationLib.inf |  45 ++
> >  StandaloneMmPkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.c         |  64 ++
> >  StandaloneMmPkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf       |  36 +
> >  37 files changed, 2894 insertions(+), 231 deletions(-)
> >  create mode 100644 ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashStandaloneMm.inf
> >  create mode 100644 MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteStandaloneMm.inf
> >  create mode 100644 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.inf
> >  create mode 100644 MdePkg/Include/Library/StandaloneMmServicesTableLib.h
> >  create mode 100644 MdePkg/Library/BaseLib/AArch64/AsmLfence.S
> >  create mode 100644 MdePkg/Library/BaseLib/AArch64/AsmLfence.asm
> >  create mode 100644 MdePkg/Library/StandaloneMmRuntimeDxe/StandaloneMmRuntimeDxe.c
> >  create mode 100644 MdePkg/Library/StandaloneMmRuntimeDxe/StandaloneMmRuntimeDxe.inf
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmHobLib/AArch64/StandaloneMmCoreHobLibInternal.c
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmHobLib/StandaloneMmHobLib.c
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmHobLib/StandaloneMmHobLib.inf
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmMemoryAllocationLib/StandaloneMmMemoryAllocationLib.c
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmMemoryAllocationLib/StandaloneMmMemoryAllocationLib.inf
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.c
> >  create mode 100644 StandaloneMmPkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf
> >
> > --
> > 2.7.4
>
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