On Wed, 7 Oct 2026 22:03:11 +0200 Maciej Fijalkowski wrote:
> The ethtool core passes RXH_XFRM_NO_CHANGE (0xff) in input_xfrm when a
> request does not touch the input transformation, e.g. when it only
> rewrites the RSS indirection table. ice_set_rxfh() tests input_xfrm only
> for RXH_XFRM_SYM_XOR, which 0xff has set, so such an update switches the
> VSI to symmetric Toeplitz hashing behind the user's back.
>
> Once symmetric-xor is reported, the core requires all hashed flow types
> to be symmetric for any following RSS set. The GTP flow types hash on
> the TEID, so every later netlink RSS update fails with "hash field config
> is not symmetric", including the one that would put the indirection
> table back.
>
> Keep the current hash function when input_xfrm is RXH_XFRM_NO_CHANGE.
> ice_set_rss_hfunc() then returns early and leaves the VSI as it is.
>
> This has been encountered while trying to run xskxceiver within drv-net
> tests where one of the setup steps was queue pull out of RSS indirection
> table.
>
> Fixes: 352e9bf23813 ("ice: enable symmetric-xor RSS for Toeplitz hash
> function")
> Signed-off-by: Maciej Fijalkowski <[email protected]>
Hm, not seeing it on the list now but I thought I submitted this
a while back:
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -3681,10 +3681,10 @@ ice_set_rxfh(struct net_device *netdev, struct
ethtool_rxfh_param *rxfh,
struct netlink_ext_ack *extack)
{
struct ice_netdev_priv *np = netdev_priv(netdev);
- u8 hfunc = ICE_AQ_VSI_Q_OPT_RSS_HASH_TPLZ;
struct ice_vsi *vsi = np->vsi;
struct ice_pf *pf = vsi->back;
struct device *dev;
+ u8 hfunc;
int err;
dev = ice_pf_to_dev(pf);
@@ -3703,9 +3703,12 @@ ice_set_rxfh(struct net_device *netdev, struct
ethtool_rxfh_param *rxfh,
return -EOPNOTSUPP;
}
- /* Update the VSI's hash function */
- if (rxfh->input_xfrm & RXH_XFRM_SYM_XOR)
+ if (rxfh->input_xfrm == RXH_XFRM_NO_CHANGE)
+ hfunc = vsi->rss_hfunc;
+ else if (rxfh->input_xfrm & RXH_XFRM_SYM_XOR)
hfunc = ICE_AQ_VSI_Q_OPT_RSS_HASH_SYM_TPLZ;
+ else /* input_xfrm == 0; core rejects any other value */
+ hfunc = ICE_AQ_VSI_Q_OPT_RSS_HASH_TPLZ;
err = ice_set_rss_hfunc(vsi, hfunc);
if (err)
Could you double check if we need the trailing else as well?
Not 100% sure now if I added it just in case or it mattered :S
