[RFC PATCH 0/7] introduce MAX_ALLOC_ADDRESS to limit boot time allocations

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

Since modifying MAX_ADDRESS to limit the memory used at boot time has
turned out to be intractible, this series proposes another approach to do
the same, by introducing MAX_ALLOC_ADDRESS for firmware internal use.

I tested these patches with ArmVirtQemu in the following way:
- limit MAX_ALLOC_ADDRESS to 0xFFFFFFFF (4 GB)
- build QEMU_EFI.fd
- run it under mach-virt with 4 GB of DRAM and highmem=off

This runs as expected, and produces a memory map ending in the following
lines

BS_Data    00000000FFFFD000-00000000FFFFFFFF 0000000000000003 0000000000000008
Available  0000000100000000-000000013FFFFFFF 0000000000040000 0000000000000008

which proves that the memory above the limit is recorded and reported by
the OS, but left untouched by the firmware memory allocation routines.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao Wu <hao.a.wu@intel.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>
Cc: Philippe Mathieu-Daude <philmd@redhat.com>

Ard Biesheuvel (7):
  MdePkg/Base: introduce MAX_ALLOC_ADDRESS
  MdeModulePkg/Dxe/Gcd: disregard memory above MAX_ALLOC_ADDRESS
  MdeModulePkg/Dxe/Page: take MAX_ALLOC_ADDRESS into account
  ArmPkg/ArmMmuLib: take MAX_ALLOC_ADDRESS into account
  ArmPlatformPkg/MemoryInitPeim: take MAX_ALLOC_ADDRESS into account
  ArmVirtPkg/MemoryInitPeiLib: split memory HOB based on
    MAX_ALLOC_ADDRESS
  MdePkg/ProcessorBind AARCH64: limit MAX_ALLOC_ADDRESS to 48 bits

 MdePkg/Include/AArch64/ProcessorBind.h        |  5 ++
 MdePkg/Include/Base.h                         |  4 ++
 .../Library/ArmMmuLib/AArch64/ArmMmuLibCore.c |  2 +-
 ArmPlatformPkg/MemoryInitPei/MemoryInitPeim.c |  4 +-
 .../ArmVirtMemoryInitPeiLib.c                 |  8 +--
 MdeModulePkg/Core/Dxe/Gcd/Gcd.c               |  8 +--
 MdeModulePkg/Core/Dxe/Mem/Page.c              | 52 +++++++++----------
 7 files changed, 46 insertions(+), 37 deletions(-)

-- 
2.19.2