On Thu, Dec 9, 2021 at 4:15 AM Eli Cohen <elic@xxxxxxxxxx> wrote:
>
> Add netlink attribute and callback function to query the control VQ
> index of a device.
>
> Example:
>
> $ vdpa dev config show vdpa-a
> vdpa-a: mac 00:00:00:00:88:88 link up link_announce false max_vq_pairs 5 \
> mtu 9000 ctrl_vq_idx 10
I still wonder about the motivation for this. And as discussed, the
ctrl_vq_idx varies depending on whether MQ is negotiated.
Thanks
>
> Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> ---
> v0 -> v1:
> 1. Use logic defined in the spec to deduce virtqueue index.
>
> drivers/vdpa/vdpa.c | 25 +++++++++++++++++++++++++
> include/uapi/linux/vdpa.h | 1 +
> 2 files changed, 26 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 3bf016e03512..b4d4b8a7ca4e 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -712,6 +712,27 @@ static int vdpa_nl_cmd_dev_get_dumpit(struct sk_buff *msg, struct netlink_callba
> return msg->len;
> }
>
> +static int vdpa_dev_net_ctrl_vq_fill(struct vdpa_device *vdev,
> + struct sk_buff *msg,
> + struct virtio_net_config *config,
> + u64 features)
> +{
> + u16 N;
> +
> + /* control VQ index, if available, is deduced according to the logic
> + * described in the virtio spec in section 5.1.2
> + */
> + if (!(features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)))
> + return 0;
> +
> + if (features & BIT_ULL(VIRTIO_NET_F_MQ))
> + N = le16_to_cpu(config->max_virtqueue_pairs);
> + else
> + N = 1;
> +
> + return nla_put_u16(msg, VDPA_ATTR_DEV_CTRL_VQ_IDX, 2 * N);
> +}
> +
> static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
> struct sk_buff *msg, u64 features,
> const struct virtio_net_config *config)
> @@ -730,6 +751,7 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
> struct virtio_net_config config = {};
> u64 features;
> u16 val_u16;
> + int err;
>
> vdpa_get_config(vdev, 0, &config, sizeof(config));
>
> @@ -746,6 +768,9 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
> return -EMSGSIZE;
>
> features = vdev->config->get_driver_features(vdev);
> + err = vdpa_dev_net_ctrl_vq_fill(vdev, msg, &config, features);
> + if (err)
> + return err;
>
> return vdpa_dev_net_mq_config_fill(vdev, msg, features, &config);
> }
> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
> index a252f06f9dfd..2e3a7f89f42d 100644
> --- a/include/uapi/linux/vdpa.h
> +++ b/include/uapi/linux/vdpa.h
> @@ -34,6 +34,7 @@ enum vdpa_attr {
> VDPA_ATTR_DEV_MAX_VQS, /* u32 */
> VDPA_ATTR_DEV_MAX_VQ_SIZE, /* u16 */
> VDPA_ATTR_DEV_MIN_VQ_SIZE, /* u16 */
> + VDPA_ATTR_DEV_CTRL_VQ_IDX, /* u16 */
>
> VDPA_ATTR_DEV_NET_CFG_MACADDR, /* binary */
> VDPA_ATTR_DEV_NET_STATUS, /* u8 */
> --
> 2.33.1
>
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