edk2-platforms/Features/Intel/PlatformPayloadFeaturePkg

Overview

• Feature Name: Platform Payload
• PI Phase(s) Supported: SMM DXE

Purpose

This package provides a common platform payload which is expected to work on most Intel platforms with a bootloader.

High-Level Theory of Operation

Bootloader initialize memory/silicon/platform and payload focus on boot media initializaiton and OS boot. Payload is expected to be re-used on different Platforms.

In the reality, some payload modules have platform dependency (e.g. only for Intel PCH) or bootloader dependency (only for coreboot). These modules would be located in edk2-platform repo.

The generic UEFI payload could be built from EDK2 UefiPayloadPkg in ELF format following universal payload specification. And a Platform Payload could be built from PlatformPayloadFeaturePkg to provide Intel platform specific features (e.g. SPI module, PCH SMM) in FV/FD format. This platform payload could be inserted into universal UEFI payload as an ELF section to generate a full-feature payload.

Firmware Volumes

• PlatformPayload.fv

Build Flows

Use Windows host as example to generate a full-feature payload:

• Setup the build env

set WORKSPACE=c:\payload
set PACKAGES_PATH=%WORKSPACE%\edk2;%WORKSPACE%\edk2-platforms\Features\Intel;%WORKSPACE%\edk2-platforms\Platform\Intel
edk2\edksetup.bat

• Build universal UEFI payload with platform payload

python edk2-platforms\Features\Intel\PlatformPayloadFeaturePkg\PlatformPayloadFeaturePkg.py -t VS2019 -D SMM_SUPPORT=TRUE -DVARIABLE_SUPPORT=NONE -D SMM_VARIABLE=TRUE

• Build universal UEFI payload then build the platform payload and patch it to the universal UEFI payload

python edk2\UefiPayloadPkg\UniversalPayloadBuild.py -t VS2019 -D SMM_SUPPORT=TRUE -DVARIABLE_SUPPORT=NONE
python edk2-platforms\Features\Intel\PlatformPayloadFeaturePkg\PlatformPayloadFeaturePkg.py -t VS2019 -D SMM_VARIABLE=TRUE -s

If build succeeds, the final UEFI payload is at Build\UefiPayloadPkgX64\UniversalPayload.elf

Note that standalone feature package build works with "-a X64" or "-a IA32 -a X64" but "-a IA32" is not supported. Note that this does not patch the universal UEFI payload, it only creates a PlatformPayload.fv.

build -p PlatformPayloadFeaturePkg/PlatformPayloadFeaturePkg.dsc -a X64 -a IA32

Features

1. SMM variable feature configuration

• PcdPlatformPayloadFeatureEnable - Enables this feature.
• SMM_VARIABLE - TRUE enables the SPI SMM variable feature implementation.

2. Modules: Currently only SMM variable feature is available. Several build macros are used as below for SMM variable feature modules.

!if $(SMM_VARIABLE) == TRUE
  ## PchSmiDispatchSmm
  ## FvbSmm
  ## FaultTolerantWriteSmm
  ## VariableSmm
  ## VariableSmmRuntimeDxe
!endif

3. Data Flows

SMM variable:

The interface with bootloader are defined in PlatformPayloadFeaturePkg\Include\Guid

SpiFlashInfoGuid.h -- SPI related information for SPI flash operation.

NvVariableInfoGuid.h -- Variable related information for SPI NV variables.

Control Flows

EDK2 DXE/SMM core from universal UEFI payload would dispatch all the modules from this platform payload.

Test Point Results

None implemented

Functional Exit Criteria

Boot to UEFI shell and verify variable functionality over resets

Feature Enabling Checklist

Verify configuration of PcdPlatformPayloadFeatureEnable and SMM_VARIABLE Boot to UEFI Shell Update a variable Reset the system and verify variable remains updated

Performance Impact

Minimal expected

Common Optimizations

None