KVM: s390: vsie: Fix redundant rmap entries

The address passed to the gmap rmap was not being masked. As a
consequence several different (but functionally equivalent) rmap
entries were being created for each shadowed table.

Fix this by properly masking the address depending on the table level.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: a2c17f9 ("KVM: s390: New gmap code")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

Author: Claudio Imbrenda

arch/s390/kvm/gmap.c

@@ -1025,6 +1025,7 @@ int gmap_insert_rmap(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)
 {
+	unsigned long bitmask;
 	union crste *crstep;
 	union pgste pgste;
 	union pte *ptep;
@@ -1041,8 +1042,9 @@ int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gf
 	if (rc)
 		return rc;
 	if (level <= TABLE_TYPE_REGION1) {
+		bitmask = -1UL << (8 + 11 * level);
 		scoped_guard(spinlock, &sg->host_to_rmap_lock)
-			rc = gmap_insert_rmap(sg, p_gfn, r_gfn, level);
+			rc = gmap_insert_rmap(sg, p_gfn, r_gfn & bitmask, level);
 	}
 	if (rc)
 		return rc;