[PATCH 0/4] KVM: x86/mmu: Fix pre-fault and map private loops

[Sean Christopherson <seanjc@google.com>]

Fix a bug in the pre-fault path where KVM fails to reload an invalidated
MMU root, which puts the KVM_PRE_FAULT_MEMORY task into an infinite loop
(although it's breakable, so not fatal to the host).  My best guess is that
the test started failing once PREEMPT_LAZY was enabled by default.

Then harden the similar "map private PFN" to also guard against unexpected
root invalidations, because Sashiko keeps pointing out that it's theoretically
possible for that code to end up in the same type of infinite loop.

Sean Christopherson (4):
  KVM: x86/mmu: Reload MMU on *every* page pre-fault attempt/iteration
  KVM: x86/mmu: Harden "map private PFN" against unexpected root
    invalidation
  KVM: x86/mmu: Top-up memory caches when retrying "map private PFN"
  KVM: x86/mmu: Add sanity check to detect stale page faults in "map
    private PFN"

 arch/x86/kvm/mmu/mmu.c | 45 +++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 16 deletions(-)


base-commit: a806d364ef288a6443a1337820ea8410a7ccc6b3
-- 
2.55.0.679.g6767b8d81c-goog