virtio: use KVM_S390_VIRTIO_RING_ALIGN instead of relying on pagesize

This doesn't really matter, since s390 pagesize is 4k anyway.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 3d44244..f5a2dbe 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -188,7 +188,8 @@
 	config = kvm_vq_config(kdev->desc)+index;
 
 	err = vmem_add_mapping(config->address,
-			       vring_size(config->num, PAGE_SIZE));
+			       vring_size(config->num,
+					  KVM_S390_VIRTIO_RING_ALIGN));
 	if (err)
 		goto out;
 
@@ -209,7 +210,8 @@
 	return vq;
 unmap:
 	vmem_remove_mapping(config->address,
-			    vring_size(config->num, PAGE_SIZE));
+			    vring_size(config->num,
+				       KVM_S390_VIRTIO_RING_ALIGN));
 out:
 	return ERR_PTR(err);
 }
@@ -220,7 +222,8 @@
 
 	vring_del_virtqueue(vq);
 	vmem_remove_mapping(config->address,
-			    vring_size(config->num, PAGE_SIZE));
+			    vring_size(config->num,
+				       KVM_S390_VIRTIO_RING_ALIGN));
 }
 
 /*