[Intel-wired-lan] [PATCH net] ice: fix vf->num_mac count with port representors

[Michal Swiatkowski]

On Thu, Apr 10, 2025 at 11:13:52AM -0700, Jacob Keller wrote:
> The ice_vc_repr_add_mac() function indicates that it does not store the MAC
> address filters in the firmware. However, it still increments vf->num_mac.
> This is incorrect, as vf->num_mac should represent the number of MAC
> filters currently programmed to firmware.
> 
> Indeed, we only perform this increment if the requested filter is a unicast
> address that doesn't match the existing vf->hw_lan_addr. In addition,
> ice_vc_repr_del_mac() does not decrement the vf->num_mac counter. This
> results in the counter becoming out of sync with the actual count.
> 
> As it turns out, vf->num_mac is currently only used in legacy made without
> port representors. The single place where the value is checked is for
> enforcing a filter limit on untrusted VFs.
> 
> Upcoming patches to support VF Live Migration will use this value when
> determining the size of the TLV for MAC address filters. Fix the
> representor mode function to stop incrementing the counter incorrectly.
> 
> Fixes: ac19e03ef780 ("ice: allow process VF opcodes in different ways")
> Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
> ---
> I am not certain if there is currently a way to trigger a bug from
> userspace due to this incorrect count, but I think it still warrants a net
> fix.
> ---
>  drivers/net/ethernet/intel/ice/ice_virtchnl.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_virtchnl.c b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> index 7c3006eb68dd071ab76e62d8715dc2729610586a..6446d0fcc0528656054e506c9208880ce1e417ea 100644
> --- a/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> +++ b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> @@ -4275,7 +4275,6 @@ static int ice_vc_repr_add_mac(struct ice_vf *vf, u8 *msg)
>  		}
>  
>  		ice_vfhw_mac_add(vf, &al->list[i]);
> -		vf->num_mac++;
>  		break;
>  	}
>  

Right, thanks for fixing it.
Reviewed-by: Michal Swiatkowski <michal.swiatkowski at linux.intel.com>

> 
> ---
> base-commit: a9843689e2de1a3727d58b4225e4f8664937aefd
> change-id: 20250410-jk-fix-v-num-mac-count-55acd188162b
> 
> Best regards,
> -- 
> Jacob Keller <jacob.e.keller at intel.com>