You might need to rebase you patch. A patch to netback went it recently.

On Mon, Sep 07, 2015 at 04:33:56PM +0100, Julien Grall wrote:

The PV network protocol is using 4KB page granularity. The goal of this
patch is to allow a Linux using 64KB page granularity working as a
network backend on a non-modified Xen.

It's only necessary to adapt the ring size and break skb data in small
chunk of 4KB. The rest of the code is relying on the grant table code.

Signed-off-by: Julien Grall <redacted>

Reviewed-by: Wei Liu <redacted>