Re: [PATCH 2/2] vdpa: Add support to update speed/duplex in vDPA/mlx5_vnet

[Dragos Tatulea <dtatulea@nvidia.com>]

(resending as I accidentally replied only to Carlos)

On 29.08.24 18:16, Carlos Bilbao wrote:
> From: Carlos Bilbao <cbilbao@digitalocean.com>
> 
> Include support to update the vDPA configuration fields of speed and
> duplex (as needed by VHOST_VDPA_SET_CONFIG). This includes function
> mlx5_vdpa_set_config() as well as changes in vdpa.c to fill the initial
> values to UNKNOWN. Also add a warning message for when
> mlx5_vdpa_get_config() receives offset and length out of bounds.
> 
> Signed-off-by: Carlos Bilbao <cbilbao@digitalocean.com>
> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 34 ++++++++++++++++++++++++++++++-
>  drivers/vdpa/vdpa.c               | 27 ++++++++++++++++++++++++
>  include/uapi/linux/vdpa.h         |  2 ++
>  3 files changed, 62 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index c47009a8b472..a44bb2072eec 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -3221,12 +3221,44 @@ static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
>  
>  	if (offset + len <= sizeof(struct virtio_net_config))
>  		memcpy(buf, (u8 *)&ndev->config + offset, len);
> +	else
> +		mlx5_vdpa_warn(mvdev, "Offset and length out of bounds\n");
>  }
>  
>  static void mlx5_vdpa_set_config(struct vdpa_device *vdev, unsigned int offset, const void *buf,
>  				 unsigned int len)
>  {
> -	/* not supported */
> +	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> +	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> +
> +	if (offset + len > sizeof(struct virtio_net_config)) {
> +		mlx5_vdpa_warn(mvdev, "Offset and length out of bounds\n");
> +		return;
> +	}
> +
> +	/*
> +	 * Note that this will update the speed/duplex configuration fields
> +	 * but the hardware support to actually perform this change does
> +	 * not exist yet.
> +	 */
> +	switch (offset) {
> +	case offsetof(struct virtio_net_config, speed):
> +		if (len == sizeof(((struct virtio_net_config *) 0)->speed))
> +			memcpy(&ndev->config.speed, buf, len);
> +		else
> +			mlx5_vdpa_warn(mvdev, "Invalid length for speed.\n");
> +		break;
> +
> +	case offsetof(struct virtio_net_config, duplex):
> +		if (len == sizeof(((struct virtio_net_config *)0)->duplex))
> +			memcpy(&ndev->config.duplex, buf, len);
> +		else
> +			mlx5_vdpa_warn(mvdev, "Invalid length for duplex.\n");
> +		break;
> +
> +	default:
> +		mlx5_vdpa_warn(mvdev, "Configuration field not supported.\n");
This will trigger noise in dmesg because there is a MAC configuration here.
> +	}
I would prefer that the .set_config remains a stub TBH. Setting the fields here is
misleading: the user might deduce that the configuration worked when they read the
values and see that they were updated.

Thanks,
dragos
>  }
>  
>  static u32 mlx5_vdpa_get_generation(struct vdpa_device *vdev)
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 4dbd2e55a288..b920e4405f6d 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -15,6 +15,7 @@
>  #include <net/genetlink.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/virtio_ids.h>
> +#include <uapi/linux/ethtool.h>
>  
>  static LIST_HEAD(mdev_head);
>  /* A global mutex that protects vdpa management device and device level operations. */
> @@ -919,6 +920,22 @@ static int vdpa_dev_net_status_config_fill(struct sk_buff *msg, u64 features,
>  	return nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16);
>  }
>  
> +static int vdpa_dev_net_speed_config_fill(struct sk_buff *msg, u64 features,
> +					struct virtio_net_config *config)
> +{
> +	__le32 speed = cpu_to_le32(SPEED_UNKNOWN);
> +
> +	return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_SPEED, sizeof(speed), &speed);
> +}
> +
> +static int vdpa_dev_net_duplex_config_fill(struct sk_buff *msg, u64 features,
> +					struct virtio_net_config *config)
> +{
> +	u8 duplex = DUPLEX_UNKNOWN;
> +
> +	return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_DUPLEX, sizeof(duplex), &duplex);
> +}
> +
>  static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
>  {
>  	struct virtio_net_config config = {};
> @@ -940,6 +957,16 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
>  
>  	if (vdpa_dev_net_status_config_fill(msg, features_device, &config))
>  		return -EMSGSIZE;
> +	/*
> +	 * mlx5_vdpa vDPA devicess currently do not support the
> +	 * VIRTIO_NET_F_SPEED_DUPLEX feature, which reports speed and
> +	 * duplex; hence these are set to UNKNOWN for now.
> +	 */
> +	if (vdpa_dev_net_speed_config_fill(msg, features_device, &config))
> +		return -EMSGSIZE;
> +
> +	if (vdpa_dev_net_duplex_config_fill(msg, features_device, &config))
> +		return -EMSGSIZE;
>  
>  	return vdpa_dev_net_mq_config_fill(msg, features_device, &config);
>  }
> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
> index 842bf1201ac4..1c64ee0dd7b1 100644
> --- a/include/uapi/linux/vdpa.h
> +++ b/include/uapi/linux/vdpa.h
> @@ -43,6 +43,8 @@ enum vdpa_attr {
>  	VDPA_ATTR_DEV_NET_STATUS,		/* u8 */
>  	VDPA_ATTR_DEV_NET_CFG_MAX_VQP,		/* u16 */
>  	VDPA_ATTR_DEV_NET_CFG_MTU,		/* u16 */
> +	VDPA_ATTR_DEV_NET_CFG_SPEED,		/* u32 */
> +	VDPA_ATTR_DEV_NET_CFG_DUPLEX,		/* u8 */
>  
>  	VDPA_ATTR_DEV_NEGOTIATED_FEATURES,	/* u64 */
>  	VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,		/* u32 */