We do not have any documentation covering using XtremIO behind IBM SVC. As both are storage arrays this would be a corner case application and not the standard. If this is a configuration qualification that you desire, I would recommend discussing with your local account team. A formal request for product qualification would have to be submitted in order for it to be tested in lab for feasibility. We do not by default test all potential configurations as that would be massive undertaking that may not be needed.
Without having deep dive knowledge of the IBM SVC, I would have to state this in generic terms. The XtremIO is not aware of what type of host is accessing the volumes present on it. If you zoned the SVC to the XtremIO and added the SVC fc ports to an IG with LUN mappings, the XtremIO would treat it like any other host and process what IO was received from it.
This being said, again I do not know if you would be able to use the SVC as pass through for the volume and what issues that may induce. The SVC would have to treat it's copy of the volume as a virtual container so that it would relay each read or write IO back to the XtremIO LUN. In terms of Dell/EMC products this would be similar to VPlex implementation.
Unless this was being done to provide high availability through multiple site IO mirroring or multiple path managing, this would impact the expected performance. As such most would opt to direct connect their host to the XtremIO.