On Sun, 28 Aug 2016 22:43:54 +0000
"Dey, Souvik" [off-list ref] wrote:

Hi ,
	Currently as you have mentioned, I have changed the code to:
static int 
 virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) 
 {
    struct virtio_hw *hw = dev->data->dev_private;
-   if (unlikely(mtu < (uint32_t)hw->vtnet_hdr_size + ETHER_HDR_LEN)) {
-       return -1;
+   if (unlikely(mtu < VIRTIO_MIN_RX_BUFSIZE || mtu > VIRTIO_MAX_RX_PKTLEN)) {
+	   PMD_INIT_LOG(ERR,"Mtu should be between 64 and 9728."
+       return -EINVAL;
    }
    return 0;
 }

Yes, we should support till 64K as the kernel does , but I need to go through the changes and test it properly before submitting it for review. Moreover I was thinking with the changes in the mtu, we should also support multi-segment buffers in kni. What do you suggest ?

This looks good, but you really don't need likely/unlikely in this code.
It is not at all performance critical.