diff options
Diffstat (limited to 'arch/x86/kvm/mmu/tdp_mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 52 |
1 files changed, 36 insertions, 16 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index d479b2b12125..853780eb033b 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -99,15 +99,18 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root, } /* - * Finds the next valid root after root (or the first valid root if root - * is NULL), takes a reference on it, and returns that next root. If root - * is not NULL, this thread should have already taken a reference on it, and - * that reference will be dropped. If no valid root is found, this - * function will return NULL. + * Returns the next root after @prev_root (or the first root if @prev_root is + * NULL). A reference to the returned root is acquired, and the reference to + * @prev_root is released (the caller obviously must hold a reference to + * @prev_root if it's non-NULL). + * + * If @only_valid is true, invalid roots are skipped. + * + * Returns NULL if the end of tdp_mmu_roots was reached. */ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, struct kvm_mmu_page *prev_root, - bool shared) + bool shared, bool only_valid) { struct kvm_mmu_page *next_root; @@ -121,9 +124,14 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots, typeof(*next_root), link); - while (next_root && !kvm_tdp_mmu_get_root(kvm, next_root)) + while (next_root) { + if ((!only_valid || !next_root->role.invalid) && + kvm_tdp_mmu_get_root(kvm, next_root)) + break; + next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, &next_root->link, typeof(*next_root), link); + } rcu_read_unlock(); @@ -143,13 +151,19 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, * mode. In the unlikely event that this thread must free a root, the lock * will be temporarily dropped and reacquired in write mode. */ -#define for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared) \ - for (_root = tdp_mmu_next_root(_kvm, NULL, _shared); \ - _root; \ - _root = tdp_mmu_next_root(_kvm, _root, _shared)) \ - if (kvm_mmu_page_as_id(_root) != _as_id) { \ +#define __for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared, _only_valid)\ + for (_root = tdp_mmu_next_root(_kvm, NULL, _shared, _only_valid); \ + _root; \ + _root = tdp_mmu_next_root(_kvm, _root, _shared, _only_valid)) \ + if (kvm_mmu_page_as_id(_root) != _as_id) { \ } else +#define for_each_valid_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared) \ + __for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared, true) + +#define for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared) \ + __for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared, false) + #define for_each_tdp_mmu_root(_kvm, _root, _as_id) \ list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link, \ lockdep_is_held_type(&kvm->mmu_lock, 0) || \ @@ -199,7 +213,10 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level); - /* Check for an existing root before allocating a new one. */ + /* + * Check for an existing root before allocating a new one. Note, the + * role check prevents consuming an invalid root. + */ for_each_tdp_mmu_root(kvm, root, kvm_mmu_role_as_id(role)) { if (root->role.word == role.word && kvm_tdp_mmu_get_root(kvm, root)) @@ -1271,7 +1288,7 @@ bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm, lockdep_assert_held_read(&kvm->mmu_lock); - for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) + for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) spte_set |= wrprot_gfn_range(kvm, root, slot->base_gfn, slot->base_gfn + slot->npages, min_level); @@ -1299,6 +1316,9 @@ retry: if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true)) continue; + if (!is_shadow_present_pte(iter.old_spte)) + continue; + if (spte_ad_need_write_protect(iter.old_spte)) { if (is_writable_pte(iter.old_spte)) new_spte = iter.old_spte & ~PT_WRITABLE_MASK; @@ -1342,7 +1362,7 @@ bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm, lockdep_assert_held_read(&kvm->mmu_lock); - for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) + for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) spte_set |= clear_dirty_gfn_range(kvm, root, slot->base_gfn, slot->base_gfn + slot->npages); @@ -1467,7 +1487,7 @@ void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, lockdep_assert_held_read(&kvm->mmu_lock); - for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) + for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) zap_collapsible_spte_range(kvm, root, slot); } |