diff -Naur linux-source-2.6.32/drivers/net/xen-netfront.c linux-source-2.6.32-xen-hack/drivers/net/xen-netfront.c
--- linux-source-2.6.32/drivers/net/xen-netfront.c  2009-12-03 03:51:21.000000000 +0000
+++ linux-source-2.6.32-xen-hack/drivers/net/xen-netfront.c 2010-09-18 13:45:45.000000000 +0000
@@ -513,9 +513,9 @@
    if (skb->ip_summed == CHECKSUM_PARTIAL)
        /* local packet? */
        tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
-   else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
-       /* remote but checksummed. */
-       tx->flags |= NETTXF_data_validated;
+// else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+//     /* remote but checksummed. */
+//     tx->flags |= NETTXF_data_validated;
 
    if (skb_shinfo(skb)->gso_size) {
        struct xen_netif_extra_info *gso;