Re: [dpdk-dev] [PATCH] net/mlx5: fix E-Switch flow without port item

[Ori Kam <orika@mellanox.com>]

Hi Yongseok,
PSB,

Ori

> -----Original Message-----
> From: Yongseok Koh
> Sent: Wednesday, April 24, 2019 12:03 AM
> To: Ori Kam <orika@mellanox.com>
> Cc: Shahaf Shuler <shahafs@mellanox.com>; Matan Azrad
> <matan@mellanox.com>; dev@dpdk.org
> Subject: Re: [PATCH] net/mlx5: fix E-Switch flow without port item
> 
> On Tue, Apr 23, 2019 at 11:19:16AM +0000, Ori Kam wrote:
> > When creating a flow rule without the port_id pattern item, always the
> > PF was selected.
> >
> > This commit fixes this issue, if no port_id pattern item is available
> > then we use the port that the flow was created on as source port.
> >
> > Fixes: 822fb3195348 ("net/mlx5: add port id item to Direct Verbs")
> >
> > Signed-off-by: Ori Kam <orika@mellanox.com>
> > ---
> >  drivers/net/mlx5/mlx5_flow_dv.c | 30 +++++++++++++++---------------
> >  1 file changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5_flow_dv.c
> b/drivers/net/mlx5/mlx5_flow_dv.c
> > index c2a2fc6..d17adbe 100644
> > --- a/drivers/net/mlx5/mlx5_flow_dv.c
> > +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> > @@ -3623,6 +3623,8 @@ struct field_modify_info modify_tcp[] = {
> >  	union flow_dv_attr flow_attr = { .attr = 0 };
> >  	struct mlx5_flow_dv_tag_resource tag_resource;
> >  	uint32_t modify_action_position = UINT32_MAX;
> > +	void *match_mask = matcher.mask.buf;
> > +	void *match_value = dev_flow->dv.value.buf;
> >
> >  	flow->group = attr->group;
> >  	if (attr->transfer)
> > @@ -3895,23 +3897,8 @@ struct field_modify_info modify_tcp[] = {
> >  	}
> >  	dev_flow->dv.actions_n = actions_n;
> >  	flow->actions = action_flags;
> > -	if (attr->ingress && !attr->transfer &&
> > -	    (priv->representor || priv->master)) {
> > -		/* It was validated - we support unidirection flows only. */
> > -		assert(!attr->egress);
> > -		/*
> > -		 * Add matching on source vport index only
> > -		 * for ingress rules in E-Switch configurations.
> > -		 */
> > -		flow_dv_translate_item_source_vport(matcher.mask.buf,
> > -						    dev_flow->dv.value.buf,
> > -						    priv->vport_id,
> > -						    0xffff);
> > -	}
> >  	for (; items->type != RTE_FLOW_ITEM_TYPE_END; items++) {
> >  		int tunnel = !!(item_flags & MLX5_FLOW_LAYER_TUNNEL);
> > -		void *match_mask = matcher.mask.buf;
> > -		void *match_value = dev_flow->dv.value.buf;
> >
> >  		switch (items->type) {
> >  		case RTE_FLOW_ITEM_TYPE_PORT_ID:
> > @@ -4018,6 +4005,19 @@ struct field_modify_info modify_tcp[] = {
> >  		}
> >  		item_flags |= last_item;
> >  	}
> > +	if (((attr->ingress && !attr->transfer) ||
> > +	     (attr->transfer && !(item_flags & MLX5_FLOW_ITEM_PORT_ID)))
> &&
> > +	    (priv->representor || priv->master)) {
> 
> From the validations, I could figure out
> - Either ingress (I) or egress (E) must be specified
> - Transfer (T) can't be egress
0> - Port ID (P) is valid only if transfer (T) is specified.
> 
> (!T and I) or (T and !P)
> = (I - T) + (T - P)
> = I - P
> 
> So, this condition is equivalent to
> 	if (attr->ingress && !!(item_flags & MLX5_FLOW_ITEM_PORT_ID) &&
> 	    (priv->representor || priv->master)) {
> 		...
> 	}
> 
> Right?
> 

You are right that we correnlty only support ingress rules for E-Switch, I want to keep it open if in future we
will support also egress for E-Switch rules, but I guess we can update it when it will be relevant.
Regarding the if you wrote there should be only one ! not 2 since this code is relevant only if the user
didn't specified port_id.

Am I right?

> If agreed, please add comment properly.
> 
> > +		/* It was validated - we support unidirection flows only. */
> > +		assert(!attr->egress);
> 
> This comment and assert are there to mention ingress and egress are
> exclusive.
> Is it still relevant? Did you also test the patch with enabling DEBUG?
> 

I will remove this code.

> > +		/*
> > +		 * Add matching on source vport index only
> > +		 * for ingress rules in E-Switch configurations.
> > +		 */
> 
> Please make this comment appropriate as well.
> 

This comment is correct, due to the second part of the if (E-Switch mode is enabled, never mind if 
it is E-Switch rule or Nic rule), but I will remove this comment and add it as part of the if updated comment.

> Thanks,
> Yongseok
> 
> > +		if (flow_dv_translate_item_port_id(dev, match_mask,
> > +						   match_value, NULL))
> > +			return -rte_errno;
> > +	}
> >  	assert(!flow_dv_check_valid_spec(matcher.mask.buf,
> >  					 dev_flow->dv.value.buf));
> >  	dev_flow->layers = item_flags;
> > --
> > 1.8.3.1
> >