[PATCH v6 20/33] KVM: s390: gmap: Make CMMA optional

Steffen Eiden seiden at linux.ibm.com
Wed Aug 12 08:36:16 PDT 2026


Guard guest CMMA behind `KVM_S390_MANAGES_S390_GUEST`. This enables
other KVM implementations to use gmap without implementing CMMA.

No functional changes.

Signed-off-by: Steffen Eiden <seiden at linux.ibm.com>
---
 arch/s390/kvm/gmap/dat.c  | 2 ++
 arch/s390/kvm/gmap/dat.h  | 2 ++
 arch/s390/kvm/gmap/gmap.c | 2 ++
 arch/s390/kvm/gmap/gmap.h | 4 +++-
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/gmap/dat.c b/arch/s390/kvm/gmap/dat.c
index f4e142995367..43ebafb56ce5 100644
--- a/arch/s390/kvm/gmap/dat.c
+++ b/arch/s390/kvm/gmap/dat.c
@@ -1059,6 +1059,7 @@ int dat_set_prefix_notif_bit(union asce asce, gfn_t gfn)
 	return 0;
 }
 
+#if KVM_S390_MANAGES_S390_GUEST
 /**
  * dat_perform_essa() - Perform ESSA actions on the PGSTE.
  * @asce: The asce to operate on.
@@ -1336,3 +1337,4 @@ int dat_set_cmma_bits(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gfn,
 	}
 	return _dat_walk_gfn_range(gfn, gfn + count, asce, &ops, DAT_WALK_IGN_HOLES, &state);
 }
+#endif /* KVM_S390_MANAGES_S390_GUEST */
diff --git a/arch/s390/kvm/gmap/dat.h b/arch/s390/kvm/gmap/dat.h
index 2cc072168810..4f11f9bbd83a 100644
--- a/arch/s390/kvm/gmap/dat.h
+++ b/arch/s390/kvm/gmap/dat.h
@@ -552,12 +552,14 @@ int dat_set_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start, gf
 int dat_set_prefix_notif_bit(union asce asce, gfn_t gfn);
 bool dat_test_age_gfn(union asce asce, gfn_t start, gfn_t end);
 
+#if KVM_S390_MANAGES_S390_GUEST
 int dat_perform_essa(union asce asce, gfn_t gfn, int orc, union essa_state *state, bool *dirty);
 long dat_reset_cmma(union asce asce, gfn_t start_gfn);
 int dat_peek_cmma(gfn_t start, union asce asce, unsigned int *count, u8 *values);
 int dat_get_cmma(union asce asce, gfn_t *start, unsigned int *count, u8 *values, atomic64_t *rem);
 int dat_set_cmma_bits(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gfn,
 		      unsigned long count, unsigned long mask, const uint8_t *bits);
+#endif /* KVM_S390_MANAGES_S390_GUEST */
 
 int kvm_s390_mmu_cache_topup(struct kvm_s390_mmu_cache *mc);
 
diff --git a/arch/s390/kvm/gmap/gmap.c b/arch/s390/kvm/gmap/gmap.c
index c1b0e2572818..86513f653850 100644
--- a/arch/s390/kvm/gmap/gmap.c
+++ b/arch/s390/kvm/gmap/gmap.c
@@ -1098,6 +1098,7 @@ int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gf
 	return 0;
 }
 
+#if KVM_S390_MANAGES_S390_GUEST
 static long __set_cmma_clean_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk)
 {
 	union pgste pgste;
@@ -1140,6 +1141,7 @@ void _gmap_set_cmma_all(struct gmap *gmap, bool dirty)
 						  &gmap->kvm->arch.cmma_dirty_pages);
 	} while (gfn);
 }
+#endif /* KVM_S390_MANAGES_S390_GUEST */
 
 static void gmap_unshadow_level(struct gmap *sg, gfn_t r_gfn, int level)
 {
diff --git a/arch/s390/kvm/gmap/gmap.h b/arch/s390/kvm/gmap/gmap.h
index 328a81c72c7a..6f3bf11d2166 100644
--- a/arch/s390/kvm/gmap/gmap.h
+++ b/arch/s390/kvm/gmap/gmap.h
@@ -110,7 +110,6 @@ int gmap_insert_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gfn
 		     gfn_t r_gfn, int level);
 int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn,
 		      kvm_pfn_t pfn, int level, bool wr);
-void _gmap_set_cmma_all(struct gmap *gmap, bool dirty);
 void _gmap_handle_vsie_unshadow_event(struct gmap *parent, gfn_t gfn);
 struct gmap *gmap_create_shadow(struct kvm_s390_mmu_cache *mc, struct gmap *gmap,
 				union asce asce, int edat_level);
@@ -204,6 +203,8 @@ static inline bool pte_needs_unshadow(union pte oldpte, union pte newpte, union
 	return !newpte.h.p || !newpte.s.pr;
 }
 
+#if KVM_S390_MANAGES_S390_GUEST
+void _gmap_set_cmma_all(struct gmap *gmap, bool dirty);
 static inline void gmap_set_cmma_all_dirty(struct gmap *gmap)
 {
 	_gmap_set_cmma_all(gmap, true);
@@ -213,6 +214,7 @@ static inline void gmap_set_cmma_all_clean(struct gmap *gmap)
 {
 	_gmap_set_cmma_all(gmap, false);
 }
+#endif /* KVM_S390_MANAGES_S390_GUEST */
 
 static inline union pgste _gmap_ptep_xchg(struct gmap *gmap, union pte *ptep, union pte newpte,
 					  union pgste pgste, gfn_t gfn, bool needs_lock)
-- 
2.53.0




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