[dpdk-stable] [PATCH] net/virtio: fix link update in speed feature case

[Maxime Coquelin]

On 10/22/21 15:17, Andrew Rybchenko wrote:
> From: Ivan Ilchenko <ivan.ilchenko at oktetlabs.ru>
> 
> Link update callback reports speed/duplex based on data
> filled on device initialization. This is wrong in case of
> VIRTIO_NET_F_SPEED_DUPLEX is negotiated since link could
> be down at this time. Fix this function to actually
> update the HW data in this case with respect to the fact
> that specifying speed via devarg is a highest priority.
> 
> Fixes: 1357b4b36246 ("net/virtio: support Virtio link speed feature")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Ivan Ilchenko <ivan.ilchenko at oktetlabs.ru>
> Signed-off-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
> ---
>   drivers/net/virtio/virtio.h        |  5 ++++
>   drivers/net/virtio/virtio_ethdev.c | 47 +++++++++++++++++++++---------
>   2 files changed, 39 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio.h b/drivers/net/virtio/virtio.h
> index e78b2e429e..4fd1427375 100644
> --- a/drivers/net/virtio/virtio.h
> +++ b/drivers/net/virtio/virtio.h
> @@ -178,6 +178,11 @@ struct virtio_hw {
>   	uint16_t port_id;
>   	uint8_t mac_addr[RTE_ETHER_ADDR_LEN];
>   	uint32_t speed;  /* link speed in MB */
> +	/*
> +	 * Speed is specified via 'speed' devarg or
> +	 * negotiated via VIRTIO_NET_F_SPEED_DUPLEX
> +	 */
> +	bool get_speed_via_feat;

For better packing of this struct, it may be better to place it just
before the speed field as it already has a 2 bytes hole above.

>   	uint8_t duplex;
>   	uint8_t intr_lsc;
>   	uint16_t max_mtu;
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index 4001368bc4..3d80f664b3 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -1777,6 +1777,32 @@ virtio_configure_intr(struct rte_eth_dev *dev)
>   
>   	return 0;
>   }
> +
> +static void
> +virtio_get_speed_duplex(struct rte_eth_dev *eth_dev,
> +			struct rte_eth_link *link)
> +{
> +	struct virtio_hw *hw = eth_dev->data->dev_private;
> +	struct virtio_net_config *config;
> +	struct virtio_net_config local_config;
> +
> +	config = &local_config;
> +	virtio_read_dev_config(hw,
> +		offsetof(struct virtio_net_config, speed),
> +		&config->speed, sizeof(config->speed));
> +	virtio_read_dev_config(hw,
> +		offsetof(struct virtio_net_config, duplex),
> +		&config->duplex, sizeof(config->duplex));
> +	hw->speed = config->speed;
> +	hw->duplex = config->duplex;
> +	if (link != NULL) {
> +		link->link_duplex = hw->duplex;
> +		link->link_speed  = hw->speed;
> +	}
> +	PMD_INIT_LOG(DEBUG, "link speed = %d, duplex = %d",
> +		     hw->speed, hw->duplex);
> +}
> +
>   #define DUPLEX_UNKNOWN   0xff
>   /* reset device and renegotiate features if needed */
>   static int
> @@ -1830,19 +1856,10 @@ virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t req_features)
>   		     hw->mac_addr[0], hw->mac_addr[1], hw->mac_addr[2],
>   		     hw->mac_addr[3], hw->mac_addr[4], hw->mac_addr[5]);
>   
> -	if (hw->speed == ETH_SPEED_NUM_UNKNOWN) {
> -		if (virtio_with_feature(hw, VIRTIO_NET_F_SPEED_DUPLEX)) {
> -			config = &local_config;
> -			virtio_read_dev_config(hw,
> -				offsetof(struct virtio_net_config, speed),
> -				&config->speed, sizeof(config->speed));
> -			virtio_read_dev_config(hw,
> -				offsetof(struct virtio_net_config, duplex),
> -				&config->duplex, sizeof(config->duplex));
> -			hw->speed = config->speed;
> -			hw->duplex = config->duplex;
> -		}
> -	}
> +	hw->get_speed_via_feat = hw->speed == ETH_SPEED_NUM_UNKNOWN &&
> +			     virtio_with_feature(hw, VIRTIO_NET_F_SPEED_DUPLEX);
> +	if (hw->get_speed_via_feat)
> +		virtio_get_speed_duplex(eth_dev, NULL);
>   	if (hw->duplex == DUPLEX_UNKNOWN)
>   		hw->duplex = ETH_LINK_FULL_DUPLEX;
>   	PMD_INIT_LOG(DEBUG, "link speed = %d, duplex = %d",
> @@ -2554,11 +2571,15 @@ virtio_dev_link_update(struct rte_eth_dev *dev, __rte_unused int wait_to_complet
>   				     dev->data->port_id);
>   		} else {
>   			link.link_status = ETH_LINK_UP;
> +			if (hw->get_speed_via_feat)
> +				virtio_get_speed_duplex(dev, &link);
>   			PMD_INIT_LOG(DEBUG, "Port %d is up",
>   				     dev->data->port_id);
>   		}
>   	} else {
>   		link.link_status = ETH_LINK_UP;
> +		if (hw->get_speed_via_feat)
> +			virtio_get_speed_duplex(dev, &link);
>   	}
>   
>   	return rte_eth_linkstatus_set(dev, &link);
> 

If you agree with the change, I can do it while applying.

Other than that:
Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>

Thanks,
Maxime