diff options
Diffstat (limited to 'arch/x86/kvm/mmu/tdp_mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 45 |
1 files changed, 28 insertions, 17 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 046b6ba31197..7cc0564f5f97 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -193,6 +193,19 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, !tdp_mmu_root_match((_root), (_types)))) { \ } else +/* + * Iterate over all TDP MMU roots in an RCU read-side critical section. + * It is safe to iterate over the SPTEs under the root, but their values will + * be unstable, so all writes must be atomic. As this routine is meant to be + * used without holding the mmu_lock at all, any bits that are flipped must + * be reflected in kvm_tdp_mmu_spte_need_atomic_write(). + */ +#define for_each_tdp_mmu_root_rcu(_kvm, _root, _as_id, _types) \ + list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link) \ + if ((_as_id >= 0 && kvm_mmu_page_as_id(_root) != _as_id) || \ + !tdp_mmu_root_match((_root), (_types))) { \ + } else + #define for_each_valid_tdp_mmu_root(_kvm, _root, _as_id) \ __for_each_tdp_mmu_root(_kvm, _root, _as_id, KVM_VALID_ROOTS) @@ -774,9 +787,6 @@ static inline void tdp_mmu_iter_set_spte(struct kvm *kvm, struct tdp_iter *iter, continue; \ else -#define tdp_mmu_for_each_pte(_iter, _kvm, _root, _start, _end) \ - for_each_tdp_pte(_iter, _kvm, _root, _start, _end) - static inline bool __must_check tdp_mmu_iter_need_resched(struct kvm *kvm, struct tdp_iter *iter) { @@ -1235,7 +1245,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) rcu_read_lock(); - tdp_mmu_for_each_pte(iter, kvm, root, fault->gfn, fault->gfn + 1) { + for_each_tdp_pte(iter, kvm, root, fault->gfn, fault->gfn + 1) { int r; if (fault->nx_huge_page_workaround_enabled) @@ -1332,21 +1342,22 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range, * from the clear_young() or clear_flush_young() notifier, which uses the * return value to determine if the page has been accessed. */ -static void kvm_tdp_mmu_age_spte(struct tdp_iter *iter) +static void kvm_tdp_mmu_age_spte(struct kvm *kvm, struct tdp_iter *iter) { u64 new_spte; if (spte_ad_enabled(iter->old_spte)) { - iter->old_spte = tdp_mmu_clear_spte_bits(iter->sptep, - iter->old_spte, - shadow_accessed_mask, - iter->level); + iter->old_spte = tdp_mmu_clear_spte_bits_atomic(iter->sptep, + shadow_accessed_mask); new_spte = iter->old_spte & ~shadow_accessed_mask; } else { new_spte = mark_spte_for_access_track(iter->old_spte); - iter->old_spte = kvm_tdp_mmu_write_spte(iter->sptep, - iter->old_spte, new_spte, - iter->level); + /* + * It is safe for the following cmpxchg to fail. Leave the + * Accessed bit set, as the spte is most likely young anyway. + */ + if (__tdp_mmu_set_spte_atomic(kvm, iter, new_spte)) + return; } trace_kvm_tdp_mmu_spte_changed(iter->as_id, iter->gfn, iter->level, @@ -1371,9 +1382,9 @@ static bool __kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, * valid roots! */ WARN_ON(types & ~KVM_VALID_ROOTS); - __for_each_tdp_mmu_root(kvm, root, range->slot->as_id, types) { - guard(rcu)(); + guard(rcu)(); + for_each_tdp_mmu_root_rcu(kvm, root, range->slot->as_id, types) { tdp_root_for_each_leaf_pte(iter, kvm, root, range->start, range->end) { if (!is_accessed_spte(iter.old_spte)) continue; @@ -1382,7 +1393,7 @@ static bool __kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, return true; ret = true; - kvm_tdp_mmu_age_spte(&iter); + kvm_tdp_mmu_age_spte(kvm, &iter); } } @@ -1904,7 +1915,7 @@ int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, *root_level = vcpu->arch.mmu->root_role.level; - tdp_mmu_for_each_pte(iter, vcpu->kvm, root, gfn, gfn + 1) { + for_each_tdp_pte(iter, vcpu->kvm, root, gfn, gfn + 1) { leaf = iter.level; sptes[leaf] = iter.old_spte; } @@ -1931,7 +1942,7 @@ u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, gfn_t gfn, struct tdp_iter iter; tdp_ptep_t sptep = NULL; - tdp_mmu_for_each_pte(iter, vcpu->kvm, root, gfn, gfn + 1) { + for_each_tdp_pte(iter, vcpu->kvm, root, gfn, gfn + 1) { *spte = iter.old_spte; sptep = iter.sptep; } |