KVM: s390: consider system MHA for guest storage

Verify that the guest maximum storage address is below the MHA (maximum
host address) value allowed on the host.

Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
[adopt to match recent limit,size changes]

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 8aa5e55..940e9ff 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1184,7 +1184,11 @@
 		kvm->arch.gmap = NULL;
 		kvm->arch.mem_limit = KVM_S390_NO_MEM_LIMIT;
 	} else {
-		kvm->arch.mem_limit = TASK_MAX_SIZE;
+		if (sclp.hamax == U64_MAX)
+			kvm->arch.mem_limit = TASK_MAX_SIZE;
+		else
+			kvm->arch.mem_limit = min_t(unsigned long, TASK_MAX_SIZE,
+						    sclp.hamax + 1);
 		kvm->arch.gmap = gmap_alloc(current->mm, kvm->arch.mem_limit - 1);
 		if (!kvm->arch.gmap)
 			goto out_err;