[ovs-dev] [PATCH v3] netdev-dpdk: add support for the RTE_ETH_EVENT_INTR_RESET event

[Ilya Maximets]

On 11.09.2019 16:20, Eelco Chaudron wrote:
> Currently, OVS does not register and therefore not handle the
> interface reset event from the DPDK framework. This would cause a
> problem in cases where a VF is used as an interface, and its
> configuration changes.
> 
> As an example in the following scenario the MAC change is not
> detected/acted upon until OVS is restarted without the patch applied:
> 
>   $ echo 1 > /sys/bus/pci/devices/0000:05:00.1/sriov_numvfs
>   $ ovs-vsctl add-port ovs_pvp_br0 dpdk0 -- \
>             set Interface dpdk0 type=dpdk -- \
>             set Interface dpdk0 options:dpdk-devargs=0000:05:0a.0
> 
>   $ ip link set p5p2 vf 0 mac 52:54:00:92:d3:33
> 
> Signed-off-by: Eelco Chaudron <echaudro at redhat.com>
> ---

<snip>

> @@ -4180,13 +4223,19 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>          && dev->rxq_size == dev->requested_rxq_size
>          && dev->txq_size == dev->requested_txq_size
>          && dev->socket_id == dev->requested_socket_id
> -        && dev->started) {
> +        && dev->started && !dev->reset_needed) {
>          /* Reconfiguration is unnecessary */
>  
>          goto out;
>      }
>  
> -    rte_eth_dev_stop(dev->port_id);
> +    if (dev->reset_needed) {
> +        rte_eth_dev_reset(dev->port_id);

Thinking more about the change and looking at flow control configuration,
it seems that on reset we'll lost configurations done in set_config().
Device reset should return it to initial state, i.e. all the default settings,
but set_config() will not be called after that.
I know, that VFs commonly doesn't support flow control, but if we'll add like
real configuration of MAC address, it will be lost too.

What do you think?

BTW, there is a discussion about flow control configuration:
https://patchwork.ozlabs.org/patch/1159689/

> +        dev->reset_needed = false;
> +    } else {
> +        rte_eth_dev_stop(dev->port_id);
> +    }
> +
>      dev->started = false;
>  
>      err = netdev_dpdk_mempool_configure(dev);