On Fri, Apr 26, 2024 at 2:54 PM Heng Qi <hengqi@xxxxxxxxxxxxxxxxx> wrote:
>
> Currently, virtio-net lacks a way to obtain the default coalesce
> values of the device during the probe phase. That is, the device
> may have default experience values, but the user uses "ethtool -c"
> to query that the values are still 0.
>
> Therefore, we reuse VIRTIO_NET_CTRL_NOTF_COAL_VQ_GET to complete the goal.
>
> Signed-off-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 68 +++++++++++++++++++++++++++++++++++-----
> 1 file changed, 61 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 3bc9b1e621db..fe0c15819dd3 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -4623,6 +4623,46 @@ static int virtnet_validate(struct virtio_device *vdev)
> return 0;
> }
>
> +static int virtnet_get_coal_init_value(struct virtnet_info *vi,
> + u16 _vqn, bool is_tx)
> +{
> + struct virtio_net_ctrl_coal *coal = &vi->ctrl->coal_vq.coal;
> + __le16 *vqn = &vi->ctrl->coal_vq.vqn;
> + struct scatterlist sgs_in, sgs_out;
> + u32 usecs, pkts, i;
> + bool ret;
> +
> + *vqn = cpu_to_le16(_vqn);
> +
> + sg_init_one(&sgs_out, vqn, sizeof(*vqn));
> + sg_init_one(&sgs_in, coal, sizeof(*coal));
> + ret = virtnet_send_command_reply(vi, VIRTIO_NET_CTRL_NOTF_COAL,
> + VIRTIO_NET_CTRL_NOTF_COAL_VQ_GET,
> + &sgs_out, &sgs_in);
> + if (!ret)
> + return ret;
> +
> + usecs = le32_to_cpu(coal->max_usecs);
> + pkts = le32_to_cpu(coal->max_packets);
> + if (is_tx) {
> + vi->intr_coal_tx.max_usecs = usecs;
> + vi->intr_coal_tx.max_packets = pkts;
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + vi->sq[i].intr_coal.max_usecs = usecs;
> + vi->sq[i].intr_coal.max_packets = pkts;
> + }
> + } else {
> + vi->intr_coal_rx.max_usecs = usecs;
> + vi->intr_coal_rx.max_packets = pkts;
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + vi->rq[i].intr_coal.max_usecs = usecs;
> + vi->rq[i].intr_coal.max_packets = pkts;
> + }
> + }
> +
> + return 0;
> +}
> +
> static bool virtnet_check_guest_gso(const struct virtnet_info *vi)
> {
> return virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
> @@ -4885,13 +4925,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> vi->intr_coal_tx.max_packets = 0;
> }
>
> - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
> - /* The reason is the same as VIRTIO_NET_F_NOTF_COAL. */
> - for (i = 0; i < vi->max_queue_pairs; i++)
> - if (vi->sq[i].napi.weight)
> - vi->sq[i].intr_coal.max_packets = 1;
> - }
> -
> #ifdef CONFIG_SYSFS
> if (vi->mergeable_rx_bufs)
> dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
> @@ -4926,6 +4959,27 @@ static int virtnet_probe(struct virtio_device *vdev)
>
> virtio_device_ready(vdev);
>
> + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
> + /* The reason is the same as VIRTIO_NET_F_NOTF_COAL. */
> + for (i = 0; i < vi->max_queue_pairs; i++)
> + if (vi->sq[i].napi.weight)
> + vi->sq[i].intr_coal.max_packets = 1;
> +
> + /* The loop exits if the default value from any
> + * queue is successfully read.
> + */
So this assumes the default values are the same. Is this something
required by the spec? If not, we probably need to iterate all the
queues.
Thanks
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + err = virtnet_get_coal_init_value(vi, rxq2vq(i), false);
> + if (!err)
> + break;
> + }
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + err = virtnet_get_coal_init_value(vi, txq2vq(i), true);
> + if (!err)
> + break;
> + }
> + }
> +
> _virtnet_set_queues(vi, vi->curr_queue_pairs);
>
> /* a random MAC address has been assigned, notify the device.
> --
> 2.32.0.3.g01195cf9f
>
