[0/2] Introduce reserved heap

Message

Henry Wang Aug. 24, 2022, 7:31 a.m. UTC

The reserved heap, or statically configured heap, refers to parts
of RAM reserved in the beginning for heap. Like the static memory
allocation, such reserved heap regions are reserved by configuration
in the device tree using physical address ranges.

This feature is useful to run Xen on Arm MPU systems, where only a
finite number of memory protection regions are available. The limited
number of protection regions places requirement on planning the use of
MPU protection regions and one or more MPU protection regions needs to
be reserved only for heap.

The first patch introduces the reserved heap and the device tree parsing
code. The second patch adds the implementation of the reserved heap
pages handling in boot and heap allocator for Arm.

Changes from RFC to v1:
- Rename the terminology to reserved heap.
- Rebase on top of latest `setup_mm()` changes.
- Added Arm32 logic in `setup_mm()`.

Henry Wang (2):
  docs, xen/arm: Introduce reserved heap memory
  xen/arm: Handle reserved heap pages in boot and heap allocator

 docs/misc/arm/device-tree/booting.txt | 46 ++++++++++++++++
 xen/arch/arm/bootfdt.c                | 51 +++++++++++++----
 xen/arch/arm/domain_build.c           |  5 +-
 xen/arch/arm/include/asm/setup.h      |  3 +
 xen/arch/arm/setup.c                  | 79 +++++++++++++++++++++------
 5 files changed, 156 insertions(+), 28 deletions(-)