[SRU][N/J:linux-azure][PATCH 0/3] [Arm64] High reboot time for 96 core Linux VMs

[John Cabaj]

BugLink: https://bugs.launchpad.net/bugs/2114218

SRU Justification

[ Impact ]

* Microsoft request to fix long boot times on arm64 VMs with 96 cores.

[ Fix ]

* Clean cherry-pick of the following patches from upstream:
* 5c63db59c5f8: "arm64: mm: Don't remap pgtables per-cont(pte|pmd) block"
* 1fcb7cea8a5f: "arm64: mm: Batch dsb and isb when populating pgtables"
* 0e9df1c905d8: "arm64: mm: Don't remap pgtables for allocate vs populat"

[ Test Plan ]

* Compile tested
* Microsoft tested

[ Where problems could occur ]

* Changes made to memory-management, which could have impacts across the memory subsystems.
* Backport involved stripping out portions of 5-level paging, which was missing prerequisite
  commits. This has been validated, but if logic was not well-separated in the upstream commits,
  the changes for present paging might have some reliance on the 5-level paging changes.

[ Other info ]

* SF#00412644

Ryan Roberts (3):
  arm64: mm: Don't remap pgtables per-cont(pte|pmd) block
  arm64: mm: Batch dsb and isb when populating pgtables
  arm64: mm: Don't remap pgtables for allocate vs populate

 arch/arm64/include/asm/pgtable.h |  7 ++-
 arch/arm64/mm/mmu.c              | 92 ++++++++++++++++++--------------
 2 files changed, 57 insertions(+), 42 deletions(-)

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2.43.0