KVM: s390: virtio-ccw: Handle command rejects.

A command reject for a ccw may happen if we run on a host not supporting
a certain feature. We want to be able to handle this as special case of
command failure, so let's split this off from the generic -EIO error code.
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

drivers/s390/kvm/virtio_ccw.c

@@ -642,8 +642,15 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
 	     (SCSW_STCTL_ALERT_STATUS | SCSW_STCTL_STATUS_PEND))) {
 		/* OK */
 	}
-	if (irb_is_error(irb))
-		vcdev->err = -EIO; /* XXX - use real error */
+	if (irb_is_error(irb)) {
+		/* Command reject? */
+		if ((scsw_dstat(&irb->scsw) & DEV_STAT_UNIT_CHECK) &&
+		    (irb->ecw[0] & SNS0_CMD_REJECT))
+			vcdev->err = -EOPNOTSUPP;
+		else
+			/* Map everything else to -EIO. */
+			vcdev->err = -EIO;
+	}
 	if (vcdev->curr_io & activity) {
 		switch (activity) {
 		case VIRTIO_CCW_DOING_READ_FEAT: