[PATCH v2 3/6] KVM: s390: Refactor dat_set_slot()

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

Refactor dat_set_slot(), _dat_slot_pte(), _dat_slot_crste(). Now they
only take a struct kvm_s390_mmu_cache as priv. For dat_delete_slot(),
mc is NULL, as no allocations should take place.

This is needed as a prerequisite to move gmap DAT table setup from
kvm_arch_commit_memory_region() to kvm_arch_prepare_memory_region().

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 arch/s390/kvm/dat.c      | 29 +++++++++--------------------
 arch/s390/kvm/dat.h      | 10 ++++------
 arch/s390/kvm/kvm-s390.c |  4 ++--
 3 files changed, 15 insertions(+), 28 deletions(-)

diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c
index f2ea013cb33e..7e5dd5a1eb1e 100644
--- a/arch/s390/kvm/dat.c
+++ b/arch/s390/kvm/dat.c
@@ -844,19 +844,12 @@ long dat_reset_skeys(union asce asce, gfn_t start)
 	return _dat_walk_gfn_range(start, asce_end(asce), asce, &ops, DAT_WALK_IGN_HOLES, NULL);
 }
 
-struct slot_priv {
-	unsigned long token;
-	struct kvm_s390_mmu_cache *mc;
-};
-
 static long _dat_slot_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk)
 {
-	struct slot_priv *p = walk->priv;
-	union crste dummy = { .val = p->token };
 	union pte new_pte, pte = READ_ONCE(*ptep);
 	union pgste pgste;
 
-	new_pte = _PTE_TOK(dummy.tok.type, dummy.tok.par);
+	new_pte = walk->priv ? _PTE_EMPTY : _PTE_TOK(_DAT_TOKEN_PIC, PGM_ADDRESSING);
 
 	/* Table entry already in the desired state. */
 	if (pte.val == new_pte.val)
@@ -873,10 +866,9 @@ static long _dat_slot_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_wal
 static long _dat_slot_crste(union crste *crstep, gfn_t gfn, gfn_t next, struct dat_walk *walk)
 {
 	union crste new_crste, crste = READ_ONCE(*crstep);
-	struct slot_priv *p = walk->priv;
+	struct kvm_s390_mmu_cache *mc = walk->priv;
 
-	new_crste.val = p->token;
-	new_crste.h.tt = crste.h.tt;
+	new_crste = mc ? _CRSTE_EMPTY(crste.h.tt) : _CRSTE_HOLE(crste.h.tt);
 
 	/* Table entry already in the desired state. */
 	if (crste.val == new_crste.val)
@@ -900,7 +892,10 @@ static long _dat_slot_crste(union crste *crstep, gfn_t gfn, gfn_t next, struct d
 	if (!crste.h.fc && !crste.h.i)
 		return 0;
 	/* Split (install a lower level table), and handle things there. */
-	return dat_split_crste(p->mc, crstep, gfn, walk->asce, false);
+	if (mc)
+		return dat_split_crste(mc, crstep, gfn, walk->asce, false);
+	/* A large page should never cross memslots boundaries */
+	return -EINVAL;
 }
 
 static const struct dat_walk_ops dat_slot_ops = {
@@ -908,16 +903,10 @@ static const struct dat_walk_ops dat_slot_ops = {
 	.crste_ops = { _dat_slot_crste, _dat_slot_crste, _dat_slot_crste, _dat_slot_crste, },
 };
 
-int dat_set_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start, gfn_t end,
-		 u16 type, u16 param)
+int dat_set_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start, gfn_t end)
 {
-	struct slot_priv priv = {
-		.token = _CRSTE_TOK(0, type, param).val,
-		.mc = mc,
-	};
-
 	return _dat_walk_gfn_range(start, end, asce, &dat_slot_ops,
-				   DAT_WALK_IGN_HOLES | DAT_WALK_ANY, &priv);
+				   DAT_WALK_IGN_HOLES | DAT_WALK_ANY, mc);
 }
 
 static void pgste_set_unlock_multiple(union pte *first, int n, union pgste *pgstes)
diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h
index 141ee7b9f019..57f32ac9ffed 100644
--- a/arch/s390/kvm/dat.h
+++ b/arch/s390/kvm/dat.h
@@ -543,8 +543,7 @@ long dat_reset_skeys(union asce asce, gfn_t start);
 unsigned long dat_get_ptval(struct page_table *table, struct ptval_param param);
 void dat_set_ptval(struct page_table *table, struct ptval_param param, unsigned long val);
 
-int dat_set_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start, gfn_t end,
-		 u16 type, u16 param);
+int dat_set_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start, gfn_t end);
 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);
 
@@ -958,16 +957,15 @@ static inline int get_level(union crste *crstep, union pte *ptep)
 	return ptep ? TABLE_TYPE_PAGE_TABLE : crstep->h.tt;
 }
 
-static inline int dat_delete_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start,
-				  unsigned long npages)
+static inline int dat_delete_slot(union asce asce, gfn_t start, unsigned long npages)
 {
-	return dat_set_slot(mc, asce, start, start + npages, _DAT_TOKEN_PIC, PGM_ADDRESSING);
+	return dat_set_slot(NULL, asce, start, start + npages);
 }
 
 static inline int dat_create_slot(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t start,
 				  unsigned long npages)
 {
-	return dat_set_slot(mc, asce, start, start + npages, _DAT_TOKEN_NONE, 0);
+	return dat_set_slot(mc, asce, start, start + npages);
 }
 
 static inline bool crste_is_ucas(union crste crste)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 91b975835457..212ff0f8eecc 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -5860,10 +5860,10 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 
 		switch (change) {
 		case KVM_MR_DELETE:
-			rc = dat_delete_slot(mc, kvm->arch.gmap->asce, old->base_gfn, old->npages);
+			rc = dat_delete_slot(kvm->arch.gmap->asce, old->base_gfn, old->npages);
 			break;
 		case KVM_MR_MOVE:
-			rc = dat_delete_slot(mc, kvm->arch.gmap->asce, old->base_gfn, old->npages);
+			rc = dat_delete_slot(kvm->arch.gmap->asce, old->base_gfn, old->npages);
 			if (rc)
 				break;
 			fallthrough;
-- 
2.55.0