[PATCH v2 16/21] net/virtio-user: allocate shadow control queue

[Eugenio Perez Martin]

On Tue, Feb 7, 2023 at 4:18 PM Maxime Coquelin
<maxime.coquelin at redhat.com> wrote:
>
> If the backends supports control virtqueue, allocate a
> shadow control virtqueue, and implement the notify callback
> that writes into the kickfd.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>

Even with the nitpick below,

Acked-by: Eugenio Pérez <eperezma at redhat.com>

> ---
>  .../net/virtio/virtio_user/virtio_user_dev.c  | 47 ++++++++++++++++++-
>  .../net/virtio/virtio_user/virtio_user_dev.h  |  5 ++
>  drivers/net/virtio/virtio_user_ethdev.c       |  6 +++
>  3 files changed, 56 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index a3584e7735..16a0e07413 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -146,8 +146,9 @@ virtio_user_dev_set_features(struct virtio_user_dev *dev)
>
>         /* Strip VIRTIO_NET_F_MAC, as MAC address is handled in vdev init */
>         features &= ~(1ull << VIRTIO_NET_F_MAC);
> -       /* Strip VIRTIO_NET_F_CTRL_VQ, as devices do not really need to know */
> -       features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
> +       /* Strip VIRTIO_NET_F_CTRL_VQ if the devices does not really support control VQ */
> +       if (!dev->hw_cvq)
> +               features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
>         features &= ~(1ull << VIRTIO_NET_F_STATUS);
>         ret = dev->ops->set_features(dev, features);
>         if (ret < 0)
> @@ -911,6 +912,48 @@ virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx)
>         }
>  }
>
> +static void
> +virtio_user_control_queue_notify(struct virtqueue *vq, void *cookie)
> +{
> +       struct virtio_user_dev *dev = cookie;
> +       uint64_t buf = 1;
> +
> +       if (write(dev->kickfds[vq->vq_queue_index], &buf, sizeof(buf)) < 0)
> +               PMD_DRV_LOG(ERR, "failed to kick backend: %s",
> +                           strerror(errno));
> +}
> +
> +int
> +virtio_user_dev_create_shadow_cvq(struct virtio_user_dev *dev, struct virtqueue *vq)
> +{
> +       char name[VIRTQUEUE_MAX_NAME_SZ];
> +       struct virtqueue *scvq;
> +
> +       snprintf(name, sizeof(name), "port%d_shadow_cvq", vq->hw->port_id);
> +       scvq = virtqueue_alloc(&dev->hw, vq->vq_queue_index, vq->vq_nentries,
> +                       VTNET_CQ, SOCKET_ID_ANY, name);
> +       if (!scvq) {
> +               PMD_INIT_LOG(ERR, "(%s) Failed to alloc shadow control vq\n", dev->path);
> +               return -ENOMEM;
> +       }
> +
> +       scvq->cq.notify_queue = &virtio_user_control_queue_notify;
> +       scvq->cq.notify_cookie = dev;
> +       dev->scvq = scvq;
> +
> +       return 0;
> +}
> +
> +void
> +virtio_user_dev_destroy_shadow_cvq(struct virtio_user_dev *dev)
> +{
> +       if (!dev->scvq)
> +               return;
> +
> +       virtqueue_free(dev->scvq);
> +       dev->scvq = NULL;
> +}
> +
>  int
>  virtio_user_dev_set_status(struct virtio_user_dev *dev, uint8_t status)
>  {
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> index 3c5453eac0..e0db4faf3f 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> @@ -58,6 +58,9 @@ struct virtio_user_dev {
>         pthread_mutex_t mutex;
>         bool            started;
>
> +       bool                    hw_cvq;
> +       struct virtqueue        *scvq;
> +
>         void *backend_data;
>  };
>
> @@ -74,6 +77,8 @@ void virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx);
>  void virtio_user_handle_cq_packed(struct virtio_user_dev *dev,
>                                   uint16_t queue_idx);
>  uint8_t virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs);
> +int virtio_user_dev_create_shadow_cvq(struct virtio_user_dev *dev, struct virtqueue *vq);
> +void virtio_user_dev_destroy_shadow_cvq(struct virtio_user_dev *dev);
>  int virtio_user_dev_set_status(struct virtio_user_dev *dev, uint8_t status);
>  int virtio_user_dev_update_status(struct virtio_user_dev *dev);
>  int virtio_user_dev_update_link_state(struct virtio_user_dev *dev);
> diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
> index 6c3e875793..626bd95b62 100644
> --- a/drivers/net/virtio/virtio_user_ethdev.c
> +++ b/drivers/net/virtio/virtio_user_ethdev.c
> @@ -232,6 +232,9 @@ virtio_user_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
>         else
>                 virtio_user_setup_queue_split(vq, dev);
>
> +       if (dev->hw_cvq && hw->cvq && (virtnet_cq_to_vq(hw->cvq) == vq))
> +               return virtio_user_dev_create_shadow_cvq(dev, vq);
> +
>         return 0;
>  }
>
> @@ -251,6 +254,9 @@ virtio_user_del_queue(struct virtio_hw *hw, struct virtqueue *vq)
>
>         close(dev->callfds[vq->vq_queue_index]);
>         close(dev->kickfds[vq->vq_queue_index]);
> +
> +       if (hw->cvq && (virtnet_cq_to_vq(hw->cvq) == vq) && dev->scvq)

Not sure if intended, but check for dev->scvq is already in
virtio_user_dev_destroy_shadow_cvq.

> +               virtio_user_dev_destroy_shadow_cvq(dev);
>  }
>
>  static void
> --
> 2.39.1
>