try_get_locked_pte
pte_t *try_get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl);
ptep = try_get_locked_pte(priv->kvm->mm, gfn_to_hva(priv->kvm, f->gfn), &ptl);
ptep = try_get_locked_pte(mm, vmaddr, &ptl);
ptep = try_get_locked_pte(mm, vmaddr, &ptl);
EXPORT_SYMBOL_GPL(try_get_locked_pte);