diff options
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_iter.c | 6 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_iter.h | 16 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 6 |
3 files changed, 22 insertions, 6 deletions
diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c index be3f096db2eb..6d3b3e5a5533 100644 --- a/arch/x86/kvm/mmu/tdp_iter.c +++ b/arch/x86/kvm/mmu/tdp_iter.c @@ -12,7 +12,7 @@ static void tdp_iter_refresh_sptep(struct tdp_iter *iter) { iter->sptep = iter->pt_path[iter->level - 1] + SHADOW_PT_INDEX(iter->gfn << PAGE_SHIFT, iter->level); - iter->old_spte = READ_ONCE(*rcu_dereference(iter->sptep)); + iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep); } static gfn_t round_gfn_for_level(gfn_t gfn, int level) @@ -89,7 +89,7 @@ static bool try_step_down(struct tdp_iter *iter) * Reread the SPTE before stepping down to avoid traversing into page * tables that are no longer linked from this entry. */ - iter->old_spte = READ_ONCE(*rcu_dereference(iter->sptep)); + iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep); child_pt = spte_to_child_pt(iter->old_spte, iter->level); if (!child_pt) @@ -123,7 +123,7 @@ static bool try_step_side(struct tdp_iter *iter) iter->gfn += KVM_PAGES_PER_HPAGE(iter->level); iter->next_last_level_gfn = iter->gfn; iter->sptep++; - iter->old_spte = READ_ONCE(*rcu_dereference(iter->sptep)); + iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep); return true; } diff --git a/arch/x86/kvm/mmu/tdp_iter.h b/arch/x86/kvm/mmu/tdp_iter.h index 216ebbe76ddd..bb9b581f1ee4 100644 --- a/arch/x86/kvm/mmu/tdp_iter.h +++ b/arch/x86/kvm/mmu/tdp_iter.h @@ -10,6 +10,22 @@ typedef u64 __rcu *tdp_ptep_t; /* + * TDP MMU SPTEs are RCU protected to allow paging structures (non-leaf SPTEs) + * to be zapped while holding mmu_lock for read. Holding RCU isn't required for + * correctness if mmu_lock is held for write, but plumbing "struct kvm" down to + * the lower depths of the TDP MMU just to make lockdep happy is a nightmare, so + * all accesses to SPTEs are done under RCU protection. + */ +static inline u64 kvm_tdp_mmu_read_spte(tdp_ptep_t sptep) +{ + return READ_ONCE(*rcu_dereference(sptep)); +} +static inline void kvm_tdp_mmu_write_spte(tdp_ptep_t sptep, u64 val) +{ + WRITE_ONCE(*rcu_dereference(sptep), val); +} + +/* * A TDP iterator performs a pre-order walk over a TDP paging structure. */ struct tdp_iter { diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 22b0c03b673b..371b6a108736 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -595,7 +595,7 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm, * here since the SPTE is going from non-present * to non-present. */ - WRITE_ONCE(*rcu_dereference(iter->sptep), 0); + kvm_tdp_mmu_write_spte(iter->sptep, 0); return 0; } @@ -634,7 +634,7 @@ static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, */ WARN_ON(is_removed_spte(iter->old_spte)); - WRITE_ONCE(*rcu_dereference(iter->sptep), new_spte); + kvm_tdp_mmu_write_spte(iter->sptep, new_spte); __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte, new_spte, iter->level, false); @@ -1069,7 +1069,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) * because the new value informs the !present * path below. */ - iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); + iter.old_spte = kvm_tdp_mmu_read_spte(iter.sptep); } if (!is_shadow_present_pte(iter.old_spte)) { |