diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 440db8891f21..71beb169d78d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1718,11 +1718,11 @@ static bool kvm_rmap_age_gfn_range(struct kvm *kvm, struct kvm_rmap_head *rmap_head; struct rmap_iterator iter; unsigned long rmap_val; + u64 old_spte, new_spte; bool young = false; u64 *sptep; gfn_t gfn; int level; - u64 spte; for (level = PG_LEVEL_4K; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { for (gfn = range->start; gfn < range->end; @@ -1730,8 +1730,8 @@ static bool kvm_rmap_age_gfn_range(struct kvm *kvm, rmap_head = gfn_to_rmap(gfn, level, range->slot); rmap_val = kvm_rmap_lock_readonly(rmap_head); - for_each_rmap_spte_lockless(rmap_val, &iter, sptep, spte) { - if (!is_accessed_spte(spte)) + for_each_rmap_spte_lockless(rmap_val, &iter, sptep, old_spte) { + if (!is_accessed_spte(old_spte)) continue; if (test_only) { @@ -1739,17 +1739,18 @@ static bool kvm_rmap_age_gfn_range(struct kvm *kvm, return true; } - if (spte_ad_enabled(spte)) - clear_bit((ffs(shadow_accessed_mask) - 1), - (unsigned long *)sptep); + if (spte_ad_enabled(old_spte)) + new_spte = old_spte & ~shadow_accessed_mask; else - /* - * If the following cmpxchg fails, the - * spte is being concurrently modified - * and should most likely stay young. - */ - cmpxchg64(sptep, spte, - mark_spte_for_access_track(spte)); + new_spte = mark_spte_for_access_track(old_spte); + + /* + * Don't bother retrying if the CMPXCHG fails, + * i.e. if another CPU modified the SPTE. The + * SPTE is either being zapped or is likely + * still in-use, i.e. is still young. + */ + cmpxchg64(sptep, old_spte, new_spte); young = true; }