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

[Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>]

On 10/29/21 12:42 PM, Maxime Coquelin wrote:
> 
> 
> On 10/22/21 15:17, Andrew Rybchenko wrote:
>> From: Ivan Ilchenko <ivan.ilchenko@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@dpdk.org
>>
>> Signed-off-by: Ivan Ilchenko <ivan.ilchenko@oktetlabs.ru>
>> Signed-off-by: Andrew Rybchenko <andrew.rybchenko@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.

Yes, please, do.

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

Many thanks,
Andrew.