Re: [PATCHv2 net-next 5/5] selftests/net: add offload checking test for virtual interface

2025-09-08, 10:14:57 +0000, Hangbin Liu wrote:

On Mon, Sep 08, 2025 at 11:36:21AM +0200, Sabrina Dubroca wrote:

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The esp-hw-offload is fixed on netdevsim

# ethtool -k eni0np1 | grep -i esp-hw-offload
esp-hw-offload: on [fixed]

There is no way to disable it.

I don't think this is intentional. nsim_ipsec_init only adds
NSIM_ESP_FEATURES to ->features but not to ->hw_features, but I think
it was just forgotten. I added a few in 494bd83bb519 ("netdevsim: add
more hw_features"), extending nsim_ipsec_init (and nsim_macsec_init
since I made the same mistake) to also add features to ->hw_features
would make sense to me.

This could be done in another patch.

If it's not needed for this series, sure.

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After we add the netdevsim to bond,
the bond also shows "esp-hw-offload off" as the flag is inherit
in dev->hw_enc_features, not dev->features.

Did you mean dev->hw_features?

No, the xfrm_features in patch 01 updates dev->hw_enc_features, not
dev->hw_features.

Ok. But hw_enc_features is not the reason ethtool shows
"esp-hw-offload off". This line is:

	bond_dev->hw_features |= BOND_XFRM_FEATURES;

(from bond_setup)

Do you think if we should update dev->hw_features in the
patch?

For dev->hw_features (and dev->features) maybe not, since that depends
on the upper device's features and implementation. I'm not sure we can
have a common function without changing the behavior on at least one
type of device.

But maybe ndo_fix_features could use a common
netdev_fix_features_from_lowers? bond/team/bridge have very similar
implementations.

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It looks the only way to check if bond dev->hw_enc_features has NETIF_F_HW_ESP
is try set xfrm offload. As

Was this test meant to check hw_enc_features?

To check hw_enc_features, I think the only way would be sending GSO
packets, since it's only used in those situations.

Oh.. That would make the test complex. Can we ignore this test first?

Ok for me.

BTW, I'm a bit lost in the callbacks.gso_segment. e.g.

esp4_gso_segment
 - xfrm4_outer_mode_gso_segment
   - xfrm4_transport_gso_segment
     - ops->callbacks.gso_segment

But who calls esp4_gso_segment? I can't find where the features is assigned.

inet_gso_segment via inet_offloads[] (ESP is a L4 proto like UDP etc).

-- 
Sabrina