On 10/19/2015 1:16 PM, Stephen Hemminger wrote: > Virtio supports a feature that allows sender to put transmit > header prepended to data. It requires that the mbuf be writeable, correct > alignment, and the feature has been negotiatied. If all this works out, > then it will be the optimum way to transmit a single segment packet. "When using legacy interfaces, transitional drivers which have not negotiated VIRTIO_F_ANY_LAYOUT MUST use a single descriptor for the struct virtio_net_hdr on both transmit and receive, with the network data in the following descriptors."
I think we shouldn't assume that virtio header descriptor uses a separate descriptor. It could be with data. Virtio RX(and dpdk vhost) actually is implemented like this before, i.e, i thought this should be inherent but not a feature. Is the current RX implementation wrong? [...]
