diff options
Diffstat (limited to 'arch/x86/kvm/mmu/tdp_mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 228f0cc5e2cf..88aff5d0512c 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -527,6 +527,10 @@ static inline bool tdp_mmu_set_spte_atomic_no_dirty_log(struct kvm *kvm, if (is_removed_spte(iter->old_spte)) return false; + /* + * Note, fast_pf_fix_direct_spte() can also modify TDP MMU SPTEs and + * does not hold the mmu_lock. + */ if (cmpxchg64(rcu_dereference(iter->sptep), iter->old_spte, new_spte) != iter->old_spte) return false; @@ -1536,3 +1540,40 @@ int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, return leaf; } + +/* + * Returns the last level spte pointer of the shadow page walk for the given + * gpa, and sets *spte to the spte value. This spte may be non-preset. If no + * walk could be performed, returns NULL and *spte does not contain valid data. + * + * Contract: + * - Must be called between kvm_tdp_mmu_walk_lockless_{begin,end}. + * - The returned sptep must not be used after kvm_tdp_mmu_walk_lockless_end. + * + * WARNING: This function is only intended to be called during fast_page_fault. + */ +u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, u64 addr, + u64 *spte) +{ + struct tdp_iter iter; + struct kvm_mmu *mmu = vcpu->arch.mmu; + gfn_t gfn = addr >> PAGE_SHIFT; + tdp_ptep_t sptep = NULL; + + tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { + *spte = iter.old_spte; + sptep = iter.sptep; + } + + /* + * Perform the rcu_dereference to get the raw spte pointer value since + * we are passing it up to fast_page_fault, which is shared with the + * legacy MMU and thus does not retain the TDP MMU-specific __rcu + * annotation. + * + * This is safe since fast_page_fault obeys the contracts of this + * function as well as all TDP MMU contracts around modifying SPTEs + * outside of mmu_lock. + */ + return rcu_dereference(sptep); +} |