[dpdk-dev] [PATCH 4/5] virtio: use any layout on transmit

Xie, Huawei huawei.xie at intel.com
Mon Oct 19 18:56:02 CEST 2015


On 10/20/2015 12:43 AM, Stephen Hemminger wrote:
> On Mon, 19 Oct 2015 16:28:30 +0000
> "Xie, Huawei" <huawei.xie at intel.com> wrote:
>
>> 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."
> The code checks for the any layout feature, what is the problem?
My reply is removed. I said virtio RX is already implemented using this
feature by default without negotiation(at the time of implementation, no
idea of this feature), is the RX implementation wrong?



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