Re: [PATCH net-next v3 11/11] virtio_net: Add get ethtool flow rules ops

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Sep 23, 2025 at 09:19:20AM -0500, Daniel Jurgens wrote:
> - Get total number of rules. There's no user interface for this. It is
>   used to allocate an appropriately sized buffer for getting all the
>   rules.
> 
> - Get specific rule
> $ ethtool -u ens9 rule 0
> 	Filter: 0
> 		Rule Type: UDP over IPv4
> 		Src IP addr: 0.0.0.0 mask: 255.255.255.255
> 		Dest IP addr: 192.168.5.2 mask: 0.0.0.0
> 		TOS: 0x0 mask: 0xff
> 		Src port: 0 mask: 0xffff
> 		Dest port: 4321 mask: 0x0
> 		Action: Direct to queue 16
> 
> - Get all rules:
> $ ethtool -u ens9
> 31 RX rings available
> Total 2 rules
> 
> Filter: 0
>         Rule Type: UDP over IPv4
>         Src IP addr: 0.0.0.0 mask: 255.255.255.255
>         Dest IP addr: 192.168.5.2 mask: 0.0.0.0
> ...
> 
> Filter: 1
>         Flow Type: Raw Ethernet
>         Src MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
>         Dest MAC addr: 08:11:22:33:44:54 mask: 00:00:00:00:00:00
> 
> Signed-off-by: Daniel Jurgens <danielj@nvidia.com>
> Reviewed-by: Parav Pandit <parav@nvidia.com>
> Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
> ---
>  drivers/net/virtio_net/virtio_net_ff.c   | 48 ++++++++++++++++++++++++
>  drivers/net/virtio_net/virtio_net_ff.h   |  6 +++
>  drivers/net/virtio_net/virtio_net_main.c | 23 ++++++++++++
>  3 files changed, 77 insertions(+)
> 
> diff --git a/drivers/net/virtio_net/virtio_net_ff.c b/drivers/net/virtio_net/virtio_net_ff.c
> index d4a34958cc42..5488300a4fc3 100644
> --- a/drivers/net/virtio_net/virtio_net_ff.c
> +++ b/drivers/net/virtio_net/virtio_net_ff.c
> @@ -809,6 +809,54 @@ int virtnet_ethtool_flow_remove(struct virtnet_ff *ff, int location)
>  	return err;
>  }
>  
> +int virtnet_ethtool_get_flow_count(struct virtnet_ff *ff,
> +				   struct ethtool_rxnfc *info)
> +{
> +	if (!ff->ff_supported)
> +		return -EOPNOTSUPP;
> +
> +	info->rule_cnt = ff->ethtool.num_rules;
> +	info->data = le32_to_cpu(ff->ff_caps->rules_limit) | RX_CLS_LOC_SPECIAL;

hmm. what if rules_limit has the high bit set?
or matches any of
#define RX_CLS_LOC_ANY          0xffffffff
#define RX_CLS_LOC_FIRST        0xfffffffe
#define RX_CLS_LOC_LAST         0xfffffffd
by chance?


> +
> +	return 0;
> +}
> +
> +int virtnet_ethtool_get_flow(struct virtnet_ff *ff,
> +			     struct ethtool_rxnfc *info)
> +{
> +	struct virtnet_ethtool_rule *eth_rule;
> +
> +	if (!ff->ff_supported)
> +		return -EOPNOTSUPP;
> +
> +	eth_rule = xa_load(&ff->ethtool.rules, info->fs.location);
> +	if (!eth_rule)
> +		return -ENOENT;
> +
> +	info->fs = eth_rule->flow_spec;
> +
> +	return 0;
> +}
> +
> +int
> +virtnet_ethtool_get_all_flows(struct virtnet_ff *ff,
> +			      struct ethtool_rxnfc *info, u32 *rule_locs)
> +{
> +	struct virtnet_ethtool_rule *eth_rule;
> +	unsigned long i = 0;
> +	int idx = 0;
> +
> +	if (!ff->ff_supported)
> +		return -EOPNOTSUPP;
> +
> +	xa_for_each(&ff->ethtool.rules, i, eth_rule)
> +		rule_locs[idx++] = i;
> +
> +	info->data = le32_to_cpu(ff->ff_caps->rules_limit);

same question

> +
> +	return 0;
> +}
> +
>  static size_t get_mask_size(u16 type)
>  {
>  	switch (type) {
> diff --git a/drivers/net/virtio_net/virtio_net_ff.h b/drivers/net/virtio_net/virtio_net_ff.h
> index 94b575fbd9ed..4bb41e64cc59 100644
> --- a/drivers/net/virtio_net/virtio_net_ff.h
> +++ b/drivers/net/virtio_net/virtio_net_ff.h
> @@ -28,6 +28,12 @@ void virtnet_ff_init(struct virtnet_ff *ff, struct virtio_device *vdev);
>  
>  void virtnet_ff_cleanup(struct virtnet_ff *ff);
>  
> +int virtnet_ethtool_get_flow_count(struct virtnet_ff *ff,
> +				   struct ethtool_rxnfc *info);
> +int virtnet_ethtool_get_all_flows(struct virtnet_ff *ff,
> +				  struct ethtool_rxnfc *info, u32 *rule_locs);
> +int virtnet_ethtool_get_flow(struct virtnet_ff *ff,
> +			     struct ethtool_rxnfc *info);
>  int virtnet_ethtool_flow_insert(struct virtnet_ff *ff,
>  				struct ethtool_rx_flow_spec *fs,
>  				u16 curr_queue_pairs);
> diff --git a/drivers/net/virtio_net/virtio_net_main.c b/drivers/net/virtio_net/virtio_net_main.c
> index 808988cdf265..e8336925c912 100644
> --- a/drivers/net/virtio_net/virtio_net_main.c
> +++ b/drivers/net/virtio_net/virtio_net_main.c
> @@ -5619,6 +5619,28 @@ static u32 virtnet_get_rx_ring_count(struct net_device *dev)
>  	return vi->curr_queue_pairs;
>  }
>  
> +static int virtnet_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info, u32 *rule_locs)
> +{
> +	struct virtnet_info *vi = netdev_priv(dev);
> +	int rc = 0;
> +
> +	switch (info->cmd) {
> +	case ETHTOOL_GRXCLSRLCNT:
> +		rc = virtnet_ethtool_get_flow_count(&vi->ff, info);
> +		break;
> +	case ETHTOOL_GRXCLSRULE:
> +		rc = virtnet_ethtool_get_flow(&vi->ff, info);
> +		break;
> +	case ETHTOOL_GRXCLSRLALL:
> +		rc = virtnet_ethtool_get_all_flows(&vi->ff, info, rule_locs);
> +		break;
> +	default:
> +		rc = -EOPNOTSUPP;
> +	}
> +
> +	return rc;
> +}
> +
>  static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info)
>  {
>  	struct virtnet_info *vi = netdev_priv(dev);
> @@ -5660,6 +5682,7 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
>  	.get_rxfh_fields = virtnet_get_hashflow,
>  	.set_rxfh_fields = virtnet_set_hashflow,
>  	.get_rx_ring_count = virtnet_get_rx_ring_count,
> +	.get_rxnfc = virtnet_get_rxnfc,
>  	.set_rxnfc = virtnet_set_rxnfc,
>  };
>  
> -- 
> 2.45.0