RE: [virtio-comment] RE: [PATCH] virtio-net: Fix virtio_net_hdr struct size when VIRTIO_NET_F_HASH_REPORT is negotiated.

[Parav Pandit <parav@nvidia.com>]

> From: Cyril Germond <cgermond@kalrayinc.com>
> Sent: Thursday, May 4, 2023 1:17 PM
> 
> Hello
> I agree VIRTIO_NET_HASH_REPORT feature is for incoming packets path.
> Nevertheless, it seems - at least to me but I may be wrong there - that the
> packet header structure data type - as described in chapter 5.1.6 Device
> Operation - is the same for the Rx and TX packets.
> Thus, if VIRTIO_NET_HASH_REPORT feature is negotiated, even for a Rx only
> feature, , the same virtio_net_hdr structure size should be used for both Rx and
> TX packets. Am I wrong ?
> Thanks,

Given the current state of the driver usage and spec it is the same size for tx and rx.

However, the delta change you proposed is modifying a generic non-network device-specific example.

We need a normative line in the section both sections.

5.1.6.2.1 Driver Requirements: Packet Transmission,
5.1.6.2.2 Device Requirements: Packet Transmission

Something like,
For the transmit virtuqueue the driver MUST prepare \field{struct virtio_net_hdr} to be the same size as that of receive virtqueue.

The device MUST consider \field{struct virtio_net_hdr} size for the transmit and the receive virtqueue to be of the same size.