8.4 Advanced Feature Design

Advanced features should be designed such that they are easily portable between minimum platform compliant implementations. In consideration of portability, it is recommended to encapsulate each feature within a dedicated package. Such encapsulation enables rapid integration of the feature and a focused area for feature-related changes. For example, feature declarations for build elements such as GUIDs, PCDs, PPIs, and protocols are scoped within the feature package DEC file. Including the feature and consequently the package imports the feature tokens within the available namespace and changes affecting the feature are localized to the package which in turn exposes the change to all feature consumers.
The Advanced Feature template should be used to describe relevant configuration for integrating the feature into a minimum platform compliant system. Any board or silicon-specific details should be abstracted such that the information is provided to the feature via "feature APIs". Such dependencies are recommended to be exposed via binary interfaces such as PPIs and protocols and can be considered similar in purpose to the architectural PPIs and Protocols defined in the PI specification. Such requirements must be included in the "Required Functions" section of the advanced feature template. Though not required, to increase portability, advanced features should not depend upon deprecated EDK II packages and attempt to reduce exposure to packages other than MdePkg and UefiCpuPkg. In turn, this decreases risk of depending upon deprecated packages in the future.