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References: <20230727172354.68243-2-dtatulea@nvidia.com>
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From:   Jason Wang <jasowang@redhat.com>
Date:   Fri, 28 Jul 2023 09:39:49 +0800
Message-ID: <CACGkMEt5+O1Q1=SvPpD5kwhEnoLNva73Uew0vaWBVXW3xE-o0Q@mail.gmail.com>
Subject: Re: [PATCH] vdpa/mlx5: Correct default number of queues when MQ is on
To:     Dragos Tatulea <dtatulea@nvidia.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
        =?UTF-8?Q?Eugenio_P=C3=A9rez?= <eperezma@redhat.com>,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
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On Fri, Jul 28, 2023 at 1:25=E2=80=AFAM Dragos Tatulea <dtatulea@nvidia.com=
> wrote:
>
> The standard specifies that the initial number of queues is the
> default, which is 1 (1 tx, 1 rx).
>
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> Reviewed-by: Eugenio P=C3=A9rez <eperezma@redhat.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/ml=
x5_vnet.c
> index 9138ef2fb2c8..6b6eb69a8a90 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2517,7 +2517,15 @@ static int mlx5_vdpa_set_driver_features(struct vd=
pa_device *vdev, u64 features)
>         else
>                 ndev->rqt_size =3D 1;
>
> -       ndev->cur_num_vqs =3D 2 * ndev->rqt_size;
> +       /* Device must start with 1 queue pair, as per VIRTIO v1.2 spec, =
section
> +        * 5.1.6.5.5 "Device operation in multiqueue mode":
> +        *
> +        * Multiqueue is disabled by default.
> +        * The driver enables multiqueue by sending a command using class
> +        * VIRTIO_NET_CTRL_MQ. The command selects the mode of multiqueue
> +        * operation, as follows: ...
> +        */
> +       ndev->cur_num_vqs =3D 2;
>
>         update_cvq_info(mvdev);
>         return err;
> --
> 2.41.0
>