Where is the actual code for UEFI boot services in EDK 2, or where the System table is being populated in EDK 2 source

Question

I am working on a Virtualization layer, in particular Virtualizing UEFI Boot Services, so that these services can be used even after ExitBootService() is called and control is passed on to GPOS kernel, be it Windows/Linux. I cannot locate actual code for boot services in EDK 2 source. Boot Services are implemented as function pointers. I cannot find the where the these functions pointers are addressed to point towards the actual function, for instance AllocatePage() boot service. where is the declaration of AllocatePage() boot service in EDK 2 source. OR else where in EDK 2 source System Table and Boot Services structure is being populated. I am also interested to see how XEN handles this particular problem. Any OVMF source is also appreciated. Thanks a lot

Answer 1

Most of default implementations of BootServices are in DxeCore (as they need to be available to all other DXE phase components). The table itself is populated here.