[RFC 0/3] Apply SRAT defined PXM to entire CFMWS

[alison.schofield@intel.com]

From: Alison Schofield <alison.schofield@intel.com>

The patch that created fake NUMA nodes for CFMWS windows
not defined in the SRAT, made wrong assumptions about the
SRAT defined entries. Specifically, it assumed an SRAT entry
using cfmws->start, uses the entire CMFWS range, start through
end. The assumption is wrong, and so the ACPI driver, needs
to examine the SRAT created memblks more closely to discover
partial definitions of the HPA range.

This work-in-progress addresses that issue. The first 2 patches
introduce numa helpers that are used in the 3rd patch, where the
ACPI drivers parsing of the CFMWS is updated.

The patch commit logs, especially Patch 3, describes more
of the approach as well as other approaches considered, and
questions. So, perhaps, scan 1 & 2, and dive into #3 and 
confirm or refute this approach.

I did not include our NUMA or ACPI friends in this posting,
because I want to get a direction check from CXL folks before
addressing how the helpers can get merged into the NUMA arch.

Thanks for looking!

Alison Schofield (3):
  x86/numa: Introduce numa_find_node(start, end)
  x86/numa: Introduce numa_remove_memblks(node, start, end)
  ACPI: NUMA: Apply SRAT proximity domain to entire CFMWS window

 arch/x86/include/asm/numa.h |  2 ++
 arch/x86/mm/numa.c          | 36 ++++++++++++++++++++++++++++++++++++
 drivers/acpi/numa/srat.c    | 32 ++++++++++++++++++++++++++------
 3 files changed, 64 insertions(+), 6 deletions(-)

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2.37.3