Re: [PATCH v1] net/mlx5: Add support for configuring max device MTU

* Re: [PATCH v1] net/mlx5: Add support for configuring max device MTU
       [not found] <20220221121927.194728-1-elic@nvidia.com>
@ 2022-02-22  4:03 ` Jason Wang
  2022-03-28 20:57 ` Michael S. Tsirkin
  1 sibling, 0 replies; 2+ messages in thread
From: Jason Wang @ 2022-02-22  4:03 UTC (permalink / raw)
  To: Eli Cohen; +Cc: Laurent Vivier, mst, virtualization, eperezma, Si-Wei Liu

On Mon, Feb 21, 2022 at 8:19 PM Eli Cohen <elic@nvidia.com> wrote:
>
> Allow an admin creating a vdpa device to specify the max MTU for the
> net device.
>
> For example, to create a device with max MTU of 1000, the following
> command can be used:
>
> $ vdpa dev add name vdpa-a mgmtdev auxiliary/mlx5_core.sf.1 mtu 1000
>
> This configuration mechanism assumes that vdpa is the sole real user of
> the function. mlx5_core could theoretically change the mtu of the
> function using the ip command on the mlx5_core net device but this
> should not be done.
>
> Reviewed-by: Si-Wei Liu<si-wei.liu@oracle.com>
> Signed-off-by: Eli Cohen <elic@nvidia.com>

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

> ---
> v0 -> v1:
> Update changelog
>
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 32 ++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 6156cf6e9377..be095dc1134e 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2689,6 +2689,28 @@ static int event_handler(struct notifier_block *nb, unsigned long event, void *p
>         return ret;
>  }
>
> +static int config_func_mtu(struct mlx5_core_dev *mdev, u16 mtu)
> +{
> +       int inlen = MLX5_ST_SZ_BYTES(modify_nic_vport_context_in);
> +       void *in;
> +       int err;
> +
> +       in = kvzalloc(inlen, GFP_KERNEL);
> +       if (!in)
> +               return -ENOMEM;
> +
> +       MLX5_SET(modify_nic_vport_context_in, in, field_select.mtu, 1);
> +       MLX5_SET(modify_nic_vport_context_in, in, nic_vport_context.mtu,
> +                mtu + MLX5V_ETH_HARD_MTU);
> +       MLX5_SET(modify_nic_vport_context_in, in, opcode,
> +                MLX5_CMD_OP_MODIFY_NIC_VPORT_CONTEXT);
> +
> +       err = mlx5_cmd_exec_in(mdev, modify_nic_vport_context, in);
> +
> +       kvfree(in);
> +       return err;
> +}
> +
>  static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
>                              const struct vdpa_dev_set_config *add_config)
>  {
> @@ -2749,6 +2771,13 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
>         mutex_init(&ndev->reslock);
>         mutex_init(&ndev->numq_lock);
>         config = &ndev->config;
> +
> +       if (add_config->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU)) {
> +               err = config_func_mtu(mdev, add_config->net.mtu);
> +               if (err)
> +                       goto err_mtu;
> +       }
> +
>         err = query_mtu(mdev, &mtu);
>         if (err)
>                 goto err_mtu;
> @@ -2867,7 +2896,8 @@ static int mlx5v_probe(struct auxiliary_device *adev,
>         mgtdev->mgtdev.device = mdev->device;
>         mgtdev->mgtdev.id_table = id_table;
>         mgtdev->mgtdev.config_attr_mask = BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR) |
> -                                         BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP);
> +                                         BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP) |
> +                                         BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU);
>         mgtdev->mgtdev.max_supported_vqs =
>                 MLX5_CAP_DEV_VDPA_EMULATION(mdev, max_num_virtio_queues) + 1;
>         mgtdev->mgtdev.supported_features = get_supported_features(mdev);
> --
> 2.35.1
>

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