KVM: x86/mmu: Refactor low level rmap helpers to prep for walking w/o mmu_lock

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Refactor the pte_list and rmap code to always read and write rmap_head->val
exactly once, e.g. by collecting changes in a local variable and then
propagating those changes back to rmap_head->val as appropriate.  This will
allow implementing a per-rmap rwlock (of sorts) by adding a LOCKED bit into
the rmap value alongside the MANY bit.

Signed-off-by: James Houghton <jthoughton@google.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: James Houghton <jthoughton@google.com>
Link: https://lore.kernel.org/r/20250204004038.1680123-9-jthoughton@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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Sean Christopherson 2025-02-04 00:40:35 +00:00

parent 8c403cf231

commit 9fb13ba6b5

1 changed files with 50 additions and 33 deletions

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arch/x86/kvm/mmu/mmu.c

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