Re: 回复: [edk2-devel] [PATCH v5 0/8] Add Variable Flash Info HOB

[Michael Kubacki]

Can you please respond with your preference?

I am ready to do this but if it is required now, it should be documented 
so it becomes a consistent pattern for future changes.

Thanks,
Michael

On 5/10/2022 11:01 AM, Michael Kubacki wrote:
> What's the plan for next steps? The v5 PR has been up for two weeks with 
> no changes.
> 
> Are we going to try to define a long-term pattern for how to include new 
> library classes in core packages or merge the patch series?
> 
> Thanks,
> Michael
> 
> On 5/5/2022 9:52 PM, Michael Kubacki wrote:
>> I still believe a long term design pattern deserves more focus and 
>> documentation than a quick modification to this series.
>>
>> Can you confirm that you envision MdePkg/MdeLibs.dsc.inc serving as a 
>> monolithic host of various other default library class instances?
>>
>> That somewhat inverts the package relationships, the code reviewer 
>> policy would need to clarify when the original package owners are 
>> included on the MdePkg patch (to confirm they agree with the default 
>> instance choice), and "core" packages would have to be clearly defined 
>> in this context for developers to know what packages are allowed.
>>
>> In addition, this does not mean there still won't be some level of 
>> platform integration thrash. For example, if a new library class 
>> instance added to MdePkg/MdeLibs.dsc.inc requires another library 
>> class (or multiple others), those might not be added to the DSC 
>> include file. They could have been satisfied in the original package 
>> DSC (or a test platform DSC) but that doesn't mean they will be in all 
>> platform DSC files. So when the MdeLibs.dsc.inc file update occurs, 
>> those platforms break and need to add the library class that was 
>> already specified in other DSC files.
>>
>> So I request that if this is the preferred approach, that it be agreed 
>> upon (e.g. dedicated RFC), documented, and consistently followed by 
>> other contributions as well.
>>
>> Regards,
>> Michael
>>
>> On 5/4/2022 9:27 PM, gaoliming wrote:
>>> Michael:
>>>    I would suggest to reuse MdePkg/MdeLibs.dsc.inc to list the 
>>> library and PCD from the edk2 core packages, such as MdePkg, 
>>> MdeModulePkg, CryptoPkg, SecurirtyPkg and so on. Those packages are 
>>> required by every platforms. They can't be separated. So, I think 
>>> MdePkg/MdeLibs.dsc.inc is for edk2 core packages, not only for MdePkg.
>>>
>>> Thanks
>>> Liming
>>>> -----邮件原件-----
>>>> 发件人: devel at edk2.groups.io <devel at edk2.groups.io> 代表 Michael
>>>> Kubacki
>>>> 发送时间: 2022年4月29日 23:48
>>>> 收件人: Ard Biesheuvel <ardb at kernel.org>
>>>> 抄送: edk2-devel-groups-io <devel at edk2.groups.io>; Abner Chang
>>>> <abner.chang at hpe.com>; Andrew Fish <afish at apple.com>; Anthony Perard
>>>> <anthony.perard at citrix.com>; Ard Biesheuvel 
>>>> <ardb+tianocore at kernel.org>;
>>>> Benjamin You <benjamin.you at intel.com>; Brijesh Singh
>>>> <brijesh.singh at amd.com>; Erdem Aktas <erdemaktas at google.com>; Gerd
>>>> Hoffmann <kraxel at redhat.com>; Guo Dong <guo.dong at intel.com>; Hao A
>>>> Wu <hao.a.wu at intel.com>; James Bottomley <jejb at linux.ibm.com>; Jian J
>>>> Wang <jian.j.wang at intel.com>; Jiewen Yao <jiewen.yao at intel.com>; Jordan
>>>> Justen <jordan.l.justen at intel.com>; Julien Grall <julien at xen.org>; Leif
>>>> Lindholm <quic_llindhol at quicinc.com>; Liming Gao
>>>> <gaoliming at byosoft.com.cn>; Maurice Ma <maurice.ma at intel.com>; Min Xu
>>>> <min.m.xu at intel.com>; Nickle Wang <nickle.wang at hpe.com>; Peter Grehan
>>>> <grehan at freebsd.org>; Ray Ni <ray.ni at intel.com>; Rebecca Cran
>>>> <rebecca at bsdio.com>; Sami Mujawar <sami.mujawar at arm.com>; Sean
>>>> Rhodes <sean at starlabs.systems>; Sebastien Boeuf
>>>> <sebastien.boeuf at intel.com>; Tom Lendacky <thomas.lendacky at amd.com>
>>>> 主题: Re: [edk2-devel] [PATCH v5 0/8] Add Variable Flash Info HOB
>>>>
>>>> I agree that would be a useful tool and in the case of changes such as
>>>> this that provide backward compatibility with existing functionality,
>>>> particularly helpful.
>>>>
>>>> Some packages such as MdePkg
>>>> (https://github.com/tianocore/edk2/blob/master/MdePkg/MdeLibs.dsc.inc)
>>>> and NetworkPkg
>>>> (https://github.com/tianocore/edk2/blob/master/NetworkPkg/NetworkCom
>>>> ponents.dsc.inc)
>>>> provide DSC files that a platform can override if necessary.
>>>>
>>>> However, this does not exist for all edk2 packages. I did not introduce
>>>> such a file in MdeModulePkg because I believe that is an independent
>>>> package design decision outside the scope of this series and, if that
>>>> change was made, it should include libraries other than just this
>>>> instance. That would lead to additional churn and a larger platform
>>>> integration debate, important to that topic, but separate from the
>>>> current state this contribution is based against.
>>>>
>>>> While includes be helpful, it can encourage platform owners to ignore
>>>> potential creep in functionality they should be aware of.
>>>>
>>>> For example, the DSC update is mostly being given to platforms to fix
>>>> their immediate build problem. But, a platform owner might also choose
>>>> to update their FVB driver to use this interface to get flash
>>>> information as opposed to directly using PCDs as many do today. 
>>>> That's a
>>>> decision they need to evaluate and make but they should be aware of the
>>>> interface and make that decision. By directly reviewing/integrating the
>>>> change for their platform, they are more explicitly made aware of this
>>>> new interface to form that decision.
>>>>
>>>> Also, when many include files get involved, platform build complexity
>>>> and developer frustration can increase due to nesting and order of
>>>> include files. Values (library classes, PCDs, etc.) can be overridden
>>>> more than once. Ultimately, this is technically manageable by utilizing
>>>> build reports and understanding the EDK II build output in more detail.
>>>>
>>>> Again, I think this conversation is useful but requires much more time
>>>> to address questions such as the following:
>>>>
>>>> 1. Should a different mechanism for default library classes be 
>>>> introduced?
>>>>
>>>> 2. Should all packages in edk2 provide such an include file? If so, 
>>>> does
>>>> it only provide the DSC file (like MdePkg) or other files (like
>>>> NetworkPkg which includes FDF)?
>>>>
>>>> 3. Which library classes for a given package should be given default
>>>> instances?
>>>>
>>>> 4. How would each platform package maintainer like to maintain their
>>>> platform build?
>>>>
>>>> Example: Would MinPlatformPkg prefer to keep its own "core" include
>>>> files
>>>> (https://github.com/tianocore/edk2-platforms/tree/master/Platform/Intel/Mi 
>>>>
>>>> nPlatformPkg/Include)
>>>> or reconcile them with include files (possibly introducing an 
>>>> additional
>>>> layer of nesting)? Would others prefer not to use includes at all to
>>>> keep a flat, simpler file?
>>>>
>>>> How would someone updating the platform code due to an edk2 change be
>>>> aware of this per-platform policy?
>>>>
>>>> To my understanding, the answers to these today are:
>>>>
>>>> 1. No
>>>> 2. No / decided on per-change basis
>>>> 3. Unknown
>>>> 4. Unknown
>>>>
>>>> (2) adds friction to the edk2 contribution process as expectation is
>>>> unclear.
>>>>
>>>> (3) adds churn into the platform integration process as the integration
>>>> process for existing code is subject to change over time (e.g. realize
>>>> library class is now in DSC and remove from platform DSC to use include
>>>> instance).
>>>>
>>>> (4) adds friction to the edk2 contribution process as expectation is
>>>> unclear. Also, somewhat error prone. There's also a level of due
>>>> diligence needed to confirm if a platform that already has an 
>>>> include is
>>>> overriding that in another DSC file. If so, is that still the correct
>>>> behavior or should it be modified.
>>>>
>>>> Regards,
>>>> Michael
>>>>
>>>> On 4/29/2022 9:45 AM, Ard Biesheuvel wrote:
>>>>> On Tue, 26 Apr 2022 at 03:29, <mikuback at linux.microsoft.com> wrote:
>>>>>>
>>>>>> From: Michael Kubacki <michael.kubacki at microsoft.com>
>>>>>>
>>>>>> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3479
>>>>>>
>>>>>> Platforms: This series introduces a new library class called
>>>>>> VariableFlashInfoLib. Platforms using the variable modules will
>>>>>> need to specify these library classes. See the patches at the
>>>>>> end of this series for examples of the change needed in the
>>>>>> platform DSC file. I have attempted to update all open-source
>>>>>> platforms in edk2 and edk2-platforms in this series and
>>>>>> https://edk2.groups.io/g/devel/message/89148.
>>>>>>
>>>>>
>>>>> I will make the same remark here as I made in response to the
>>>>> edk2-platforms series:
>>>>>
>>>>> Could we please consider introducing a way to define the default
>>>>> resolution of a library class? That way, all this churn and
>>>>> unnecessary breakage would not be necessary, as defining a resolution
>>>>> would only be necessary when deviating from the default. In fact, we
>>>>> might be able to clean up some .DSCs considerably by defining defaults
>>>>> for library classes that only have one (or very few) implementations.
>>>>>
>>>>>
>>>>>> The UEFI variable drivers such as VariableRuntimeDxe, VariableSmm,
>>>>>> VariableStandaloneMm, etc. (and their dependent protocol/library
>>>>>> stack), typically acquire UEFI variable store flash information
>>>>>> with PCDs declared in MdeModulePkg.
>>>>>>
>>>>>> For example:
>>>>>> [Pcd]
>>>>>>     gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
>>>>>>
>>>> gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase64
>>>>>>     gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
>>>>>>
>>>>>> These PCDs work as-is in the StandaloneMm driver if they are not
>>>>>> dynamic such as Dynamic or DynamicEx because PCD services are not
>>>>>> readily available in the Standalone MM environment. Platforms that
>>>>>> use Standalone MM today, must define these PCDs as FixedAtBuild in
>>>>>> their platform build. However, the PCDs do allow platforms to treat
>>>>>> the PCDs as Dynamic/DynamicEx and being able to support that is
>>>>>> currently a gap for Standalone MM.
>>>>>>
>>>>>> This patch series introduces a HOB that can be produced by the
>>>>>> platform to provide the same information. The HOB list is
>>>>>> available to Standalone MM.
>>>>>>
>>>>>> The PCD declarations are left as-is in MdeModulePkg for backward
>>>>>> compatibility. This means unless a platform wants to use the HOB,
>>>>>> their code will continue to work with no change (they do not need
>>>>>> to produce the HOB). Only if the HOB is found, is its value used
>>>>>> instead of the PCDs.
>>>>>>
>>>>>> Due to the large number of consumers of this information, access
>>>>>> to the base address and size values is abstracted in a new library
>>>>>> class (as requested in the v1 series) called VariableFlashInfoLib.
>>>>>>
>>>>>> The API of VariableFlashInfoLib does not bind the underlying data
>>>>>> structure to the information returned to library users to allow
>>>>>> flexibility in the library implementation in the future.
>>>>>>
>>>>>> V5 changes.
>>>>>> 1. Made GetVariableFlashInfoFromHob() in BaseVariableFlashInfoLib.c
>>>>>>      STATIC.
>>>>>> 2. Added a section in commit v5 [3/8] to explicitly state that the
>>>>>>      commit introduces a dependency that requires a change in 
>>>>>> platform
>>>>>>      build.  Please see patches v5 [5/8] - v5 [8/8] for examples of
>>>>>>      how to integrate this change (add VariableFlashInfoLib library
>>>>>>      to DSC file).
>>>>>>
>>>>>> V4 changes:
>>>>>> 1. Add a UINT32 "Reserved" field to VARIABLE_FLASH_INFO.
>>>>>> 2. Add a descriptive comment to VariableFlashInfo.h to explain
>>>>>>      HOB usage.
>>>>>>
>>>>>> V3 changes:
>>>>>> 1. To better clarify usage, renamed the members
>>>>>>      "NvStorageBaseAddress" and "NvStorageLength" in
>>>>>>      "VARIABLE_FLASH_INFO" to "NvVariableBaseAddress" and
>>>>>>      "NvVariableLength".
>>>>>> 2. Added description comments to the fields in "VARIABLE_FLASH_INFO".
>>>>>>
>>>>>> V2 changes:
>>>>>> 1. Abstracted flash info data access with VariableFlashInfoLib.
>>>>>> 2. Updated package builds in the repo that build the variable and
>>>>>>      FTW drivers to include VariableFlashInfoLib.
>>>>>> 3. Removed a redundant variable assignment in VariableSmm.c.
>>>>>> 4. Updated comments in FtwMisc.c and FaultTolerantWritePei.c to
>>>>>>      indicate driver assumption is UINTN (not UINT32)
>>>>>> 5. Added a version field to the VARIABLE_FLASH_INFO structure.
>>>>>>
>>>>>> Cc: Abner Chang <abner.chang at hpe.com>
>>>>>> Cc: Andrew Fish <afish at apple.com>
>>>>>> Cc: Anthony Perard <anthony.perard at citrix.com>
>>>>>> Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
>>>>>> Cc: Benjamin You <benjamin.you at intel.com>
>>>>>> Cc: Brijesh Singh <brijesh.singh at amd.com>
>>>>>> Cc: Erdem Aktas <erdemaktas at google.com>
>>>>>> Cc: Gerd Hoffmann <kraxel at redhat.com>
>>>>>> Cc: Guo Dong <guo.dong at intel.com>
>>>>>> Cc: Hao A Wu <hao.a.wu at intel.com>
>>>>>> Cc: James Bottomley <jejb at linux.ibm.com>
>>>>>> Cc: Jian J Wang <jian.j.wang at intel.com>
>>>>>> Cc: Jiewen Yao <jiewen.yao at intel.com>
>>>>>> Cc: Jordan Justen <jordan.l.justen at intel.com>
>>>>>> Cc: Julien Grall <julien at xen.org>
>>>>>> Cc: Leif Lindholm <quic_llindhol at quicinc.com>
>>>>>> Cc: Liming Gao <gaoliming at byosoft.com.cn>
>>>>>> Cc: Maurice Ma <maurice.ma at intel.com>
>>>>>> Cc: Min Xu <min.m.xu at intel.com>
>>>>>> Cc: Nickle Wang <nickle.wang at hpe.com>
>>>>>> Cc: Peter Grehan <grehan at freebsd.org>
>>>>>> Cc: Ray Ni <ray.ni at intel.com>
>>>>>> Cc: Rebecca Cran <rebecca at bsdio.com>
>>>>>> Cc: Sami Mujawar <sami.mujawar at arm.com>
>>>>>> Cc: Sean Rhodes <sean at starlabs.systems>
>>>>>> Cc: Sebastien Boeuf <sebastien.boeuf at intel.com>
>>>>>> Cc: Tom Lendacky <thomas.lendacky at amd.com>
>>>>>> Signed-off-by: Michael Kubacki <michael.kubacki at microsoft.com>
>>>>>>
>>>>>> Michael Kubacki (8):
>>>>>>     MdeModulePkg: Add Variable Flash Info HOB
>>>>>>     MdeModulePkg/VariableFlashInfoLib: Add initial library
>>>>>>     MdeModulePkg/Variable: Consume Variable Flash Info
>>>>>>     MdeModulePkg/FaultTolerantWrite: Consume Variable Flash Info
>>>>>>     ArmVirtPkg/ArmVirt.dsc.inc: Add VariableFlashInfoLib
>>>>>>     EmulatorPkg: Add VariableFlashInfoLib
>>>>>>     OvmfPkg: Add VariableFlashInfoLib
>>>>>>     UefiPayloadPkg: Add VariableFlashInfoLib
>>>>>>
>>>>>>
>>>> MdeModulePkg/Library/BaseVariableFlashInfoLib/BaseVariableFlashInfoLib.c 
>>>>
>>>> | 179 ++++++++++++++++++++
>>>>>>    MdeModulePkg/Universal/FaultTolerantWriteDxe/FtwMisc.c
>>>> |  41 +++--
>>>>>>
>>>> MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c
>>>> |   7 +-
>>>>>>
>>>> MdeModulePkg/Universal/FaultTolerantWritePei/FaultTolerantWritePei.c
>>>> |  28 +--
>>>>>>    MdeModulePkg/Universal/Variable/Pei/Variable.c
>>>> |  14 +-
>>>>>>    MdeModulePkg/Universal/Variable/RuntimeDxe/VariableDxe.c
>>>> |  16 +-
>>>>>>    MdeModulePkg/Universal/Variable/RuntimeDxe/VariableNonVolatile.c
>>>> |  14 +-
>>>>>>    MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
>>>> |  17 +-
>>>>>>    ArmVirtPkg/ArmVirt.dsc.inc
>>>> |   1 +
>>>>>>    EmulatorPkg/EmulatorPkg.dsc
>>>> |   1 +
>>>>>>    MdeModulePkg/Include/Guid/VariableFlashInfo.h
>>>> | 111 ++++++++++++
>>>>>>    MdeModulePkg/Include/Library/VariableFlashInfoLib.h
>>>> |  68 ++++++++
>>>>>>
>>>> MdeModulePkg/Library/BaseVariableFlashInfoLib/BaseVariableFlashInfoLib.i 
>>>>
>>>> nf      |  48 ++++++
>>>>>>
>>>> MdeModulePkg/Library/BaseVariableFlashInfoLib/BaseVariableFlashInfoLib.u 
>>>>
>>>> ni      |  12 ++
>>>>>>    MdeModulePkg/MdeModulePkg.dec
>>>> |   8 +
>>>>>>    MdeModulePkg/MdeModulePkg.dsc
>>>> |   2 +
>>>>>>    MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWrite.h
>>>> |   7 +-
>>>>>>
>>>> MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteDxe.inf
>>>> |  10 +-
>>>>>>
>>>> MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.inf
>>>> |  10 +-
>>>>>>
>>>> MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteStandal
>>>> oneMm.inf |  10 +-
>>>>>>
>>>> MdeModulePkg/Universal/FaultTolerantWritePei/FaultTolerantWritePei.inf
>>>> |  10 +-
>>>>>>    MdeModulePkg/Universal/Variable/Pei/Variable.h
>>>> |   2 +
>>>>>>    MdeModulePkg/Universal/Variable/Pei/VariablePei.inf
>>>> |   5 +-
>>>>>>    MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.h
>>>> |   7 +-
>>>>>>
>>>> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
>>>> |   5 +-
>>>>>>    MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
>>>> |   5 +-
>>>>>>
>>>> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.inf
>>>> |   5 +-
>>>>>>    OvmfPkg/AmdSev/AmdSevX64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/Bhyve/BhyveX64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/CloudHv/CloudHvX64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/IntelTdx/IntelTdxX64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/Microvm/MicrovmX64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/OvmfPkgIa32.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/OvmfPkgIa32X64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/OvmfPkgX64.dsc
>>>> |   1 +
>>>>>>    OvmfPkg/OvmfXen.dsc
>>>> |   1 +
>>>>>>    UefiPayloadPkg/UefiPayloadPkg.dsc
>>>> |   1 +
>>>>>>    37 files changed, 559 insertions(+), 94 deletions(-)
>>>>>>    create mode 100644
>>>> MdeModulePkg/Library/BaseVariableFlashInfoLib/BaseVariableFlashInfoLib.c 
>>>>
>>>>>>    create mode 100644 MdeModulePkg/Include/Guid/VariableFlashInfo.h
>>>>>>    create mode 100644
>>>> MdeModulePkg/Include/Library/VariableFlashInfoLib.h
>>>>>>    create mode 100644
>>>> MdeModulePkg/Library/BaseVariableFlashInfoLib/BaseVariableFlashInfoLib.i 
>>>>
>>>> nf
>>>>>>    create mode 100644
>>>> MdeModulePkg/Library/BaseVariableFlashInfoLib/BaseVariableFlashInfoLib.u 
>>>>
>>>> ni
>>>>>>
>>>>>> -- 
>>>>>> 2.28.0.windows.1
>>>>>>
>>>>
>>>>
>>>> 
>>>>
>>>
>>>


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