[0/3] KVM: x86/mmu: Don't zap "direct" non-leaf SPTEs on memslot removal

Message

Sean Christopherson Oct. 9, 2024, 7:23 p.m. UTC

When doing a targeted zap during memslot removal (DELETE or MOVE) zap only
leaf SPTEs and non-leaf SPTEs with gPTEs, as zapping non-leaf SPTEs without
gPTEs is unnecessary and weird because sp->gfn for such SPTEs is rounded,
i.e. night tightly coupled to the memslot.

Massage the related documentation so that KVM doesn't get stuck maintaining
undesirable ABI (again), and opportunistically add a lockdep assertion in
kvm_unmap_gfn_range() (largely because I keep forgetting that memslot updates
are special).

Sean Christopherson (3):
  KVM: x86/mmu: Zap only SPs that shadow gPTEs when deleting memslot
  KVM: x86/mmu: Add lockdep assert to enforce safe usage of
    kvm_unmap_gfn_range()
  KVM: x86: Clean up documentation for KVM_X86_QUIRK_SLOT_ZAP_ALL

 Documentation/virt/kvm/api.rst | 16 +++++++++-------
 arch/x86/kvm/mmu/mmu.c         | 26 ++++++++++++++++----------
 2 files changed, 25 insertions(+), 17 deletions(-)


base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b