ce.val, IPTE_GLOBAL);
+		else
+			__ptep_ipte(gfn_to_gpa(gfn), (void *)ptep, 0, 0, IPTE_GLOBAL);
+	}
+
+	if (uses_skeys) {
+		if (old.h.i && !new.h.i)
+			/* Invalid to valid: restore storage keys from PGSTE */
+			dat_set_storage_key_from_pgste(new, pgste);
+		else if (!old.h.i && new.h.i)
+			/* Valid to invalid: save storage keys to PGSTE */
+			pgste = dat_save_storage_key_into_pgste(old, pgste);
+		else if (!old.h.i && !new.h.i)
+			/* Valid to valid: move storage keys */
+			if (old.h.pfra != new.h.pfra)
+				dat_move_storage_key(old, new);
+		/* Invalid to invalid: nothing to do */
+	}
+
+	WRITE_ONCE(*ptep, new);
+	return pgste;
+}
diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h
index 4c75d3f75b33..c0644021c92f 100644
--- a/arch/s390/kvm/dat.h
+++ b/arch/s390/kvm/dat.h
@@ -430,6 +430,12 @@ struct kvm_s390_mmu_cache {
 	short int n_rmaps;
 };
 
+union pgste __must_check __dat_ptep_xchg(union pte *ptep, union pgste pgste, union pte new,
+					 gfn_t gfn, union asce asce, bool uses_skeys);
+bool dat_crstep_xchg_atomic(union crste *crstep, union crste old, union crste new, gfn_t gfn,
+			    union asce asce);
+void dat_crstep_xchg(union crste *crstep, union crste new, gfn_t gfn, union asce asce);
+
 void dat_free_level(struct crst_table *table, bool owns_ptes);
 struct crst_table *dat_alloc_crst_sleepable(unsigned long init);
 
@@ -757,6 +763,21 @@ static inline void pgste_set_unlock(union pte *ptep, union pgste pgste)
 	WRITE_ONCE(*pgste_of(ptep), pgste);
 }
 
+static inline void dat_ptep_xchg(union pte *ptep, union pte new, gfn_t gfn, union asce asce,
+				 bool has_skeys)
+{
+	union pgste pgste;
+
+	pgste = pgste_get_lock(ptep);
+	pgste = __dat_ptep_xchg(ptep, pgste, new, gfn, asce, has_skeys);
+	pgste_set_unlock(ptep, pgste);
+}
+
+static inline void dat_ptep_clear(union pte *ptep, gfn_t gfn, union asce asce, bool has_skeys)
+{
+	dat_ptep_xchg(ptep, _PTE_EMPTY, gfn, asce, has_skeys);
+}
+
 static inline void dat_free_pt(struct page_table *pt)
 {
 	free_page((unsigned long)pt);
@@ -794,4 +815,23 @@ static inline struct kvm_s390_mmu_cache *kvm_s390_new_mmu_cache(void)
 	return NULL;
 }
 
+static inline bool dat_pmdp_xchg_atomic(union pmd *pmdp, union pmd old, union pmd new,
+					gfn_t gfn, union asce asce)
+{
+	return dat_crstep_xchg_atomic(_CRSTEP(pmdp), _CRSTE(old), _CRSTE(new), gfn, asce);
+}
+
+static inline bool dat_pudp_xchg_atomic(union pud *pudp, union pud old, union pud new,
+					gfn_t gfn, union asce asce)
+{
+	return dat_crstep_xchg_atomic(_CRSTEP(pudp), _CRSTE(old), _CRSTE(new), gfn, asce);
+}
+
+static inline void dat_crstep_clear(union crste *crstep, gfn_t gfn, union asce asce)
+{
+	union crste newcrste = _CRSTE_EMPTY(crstep->h.tt);
+
+	dat_crstep_xchg(crstep, newcrste, gfn, asce);
+}
+
 #endif /* __KVM_S390_DAT_H */
-- 
2.52.0[PATCH v6 14/28] KVM: s390: KVM page table management functions: clear and replaceClaudio Imbrenda <imbrenda@linux.ibm.com> undefinedkvm@vger.kernel.org undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined…