Add the the capability to load HW RX checsum in eBPF programs

[kernel-patches-daemon-bpf]

Pull request for series with
subject: Add the the capability to load HW RX checsum in eBPF programs
version: 2
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1053970

[kernel-patches-daemon-bpf]

Upstream branch: 561085f
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1053970
version: 2

[kernel-patches-review-bot]

commit 62409dc1970e8f75df71ca4a0e37440c48d3ba16
Author: Lorenzo Bianconi <lorenzo@kernel.org>

netlink: specs: Add XDP RX checksum capability to XDP metadata specs

This patch adds XDP RX checksum capability to the XDP metadata
infrastructure, introducing the bpf_xdp_metadata_rx_checksum() kfunc,
enum xdp_checksum, and the xmo_rx_checksum netdev callback.

> Moreover, introduce xmo_rx_checksum netdev callback in order allow the
> eBPF program bounded to the device to retrieve the RX checksum result

This isn't a bug, but "in order allow" should be "in order to allow",
and "bounded" should be "bound".

> diff --git a/net/core/xdp.c b/net/core/xdp.c
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c

[ ... ]

> +/**
> + * bpf_xdp_metadata_rx_checksum - Read XDP frame RX checksum.
> + * @ctx: XDP context pointer.
> + * @ip_summed: Return value pointer indicating checksum result.
> + * @cksum_meta: Return value pointer indicating checksum result metadata.
> + *
> + * In case of success, ``ip_summed`` is set to the RX checksum result. Possible
> + * values are:
> + * ``XDP_CHECKSUM_NONE``
> + * ``XDP_CHECKSUM_UNNECESSARY``
> + * ``XDP_CHECKSUM_COMPLETE``
> + *
> + * In case of success, ``cksum_meta`` contains the hw computed checksum value
> + * for ``XDP_CHECKSUM_COMPLETE`` or the ``csum_level`` for
> + * ``XDP_CHECKSUM_UNNECESSARY``. It is set to 0 for ``XDP_CHECKSUM_NONE``
> + *
> + * Return:
> + * * Returns 0 on success or ``-errno`` on error.
> + * * ``-EOPNOTSUPP`` : means device driver does not implement kfunc
> + * * ``-ENODATA``    : means no RX-timestamp available for this frame
                                      ^^^^^^^^^^^^

Should this say "RX-checksum" instead of "RX-timestamp"? This looks
like it was copied from bpf_xdp_metadata_rx_timestamp().

> + */
> +__bpf_kfunc int bpf_xdp_metadata_rx_checksum(const struct xdp_md *ctx,
> +					     enum xdp_checksum *ip_summed,
> +					     u32 *cksum_meta)
> +{
> +	return -EOPNOTSUPP;
> +}

---

AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

In-Reply-To-Subject: netlink: specs: Add XDP RX checksum capability to XDP metadata specs
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/21992879200

AI-authorship-score: low
AI-authorship-explanation: Grammar mistakes and copy-paste error in kdoc are characteristic of human authorship by a non-native English speaker; Lorenzo Bianconi is an established kernel contributor.
issues-found: 2
issue-severity-score: low
issue-severity-explanation: Both issues are documentation errors: a copy-paste error in the kdoc (-ENODATA description says RX-timestamp instead of RX-checksum) and commit message grammar mistakes; neither affects runtime behavior.

[kernel-patches-review-bot]

commit 2575749a24c12a529326767f6c56ffbaa255e638
Author: Lorenzo Bianconi <lorenzo@kernel.org>

net: veth: Add xmo_rx_checksum callback to veth driver

Adds the xmo_rx_checksum XDP metadata callback to the veth driver,
translating skb checksum state into enum xdp_checksum values for
eBPF programs.

> diff --git a/drivers/net/veth.c b/drivers/net/veth.c
> index 9982412fd7f2..3ec77599299a 100644
> --- a/drivers/net/veth.c
> +++ b/drivers/net/veth.c
> @@ -1697,6 +1697,35 @@ static int veth_xdp_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto,
>  	return err;
>  }
>
> +static int veth_xdp_rx_checksum(const struct xdp_md *ctx,
> +				enum xdp_checksum *ip_summed,
> +				u32 *cksum_meta)
> +{
> +	const struct veth_xdp_buff *_ctx = (void *)ctx;
> +	const struct sk_buff *skb = _ctx->skb;
> +
> +	if (!skb)
> +		return -ENODATA;
> +
> +	*ip_summed = skb->ip_summed;

Is this assignment needed? Every branch in the switch below overwrites
*ip_summed, so this line has no effect. It looks like a leftover from v1
where the raw skb->ip_summed was the intended output value.

> +	switch (skb->ip_summed) {
> +	case CHECKSUM_COMPLETE:
> +		*ip_summed = XDP_CHECKSUM_COMPLETE;
> +		*cksum_meta = skb->csum;
> +		break;
> +	case CHECKSUM_UNNECESSARY:
> +		*ip_summed = XDP_CHECKSUM_UNNECESSARY;
> +		*cksum_meta = skb->csum_level;
> +		break;
> +	default:
> +		*ip_summed = XDP_CHECKSUM_NONE;
> +		*cksum_meta = 0;
> +		break;
> +	}

[ ... ]

---

AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

In-Reply-To-Subject: net: veth: Add xmo_rx_checksum callback to veth driver
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/21992879200

AI-authorship-score: low
AI-authorship-explanation: Multiple version iterations over months with incremental refinements, a non-native English typo, and a refactoring leftover are all characteristic of human development.
issues-found: 1
issue-severity-score: low
issue-severity-explanation: Dead code assignment from v1 refactoring leftover has no functional impact but is unnecessary.

[kernel-patches-review-bot]

commit 46a9e252f458a204c9c8ce143fcef4cfde25a702
Author: Lorenzo Bianconi <lorenzo@kernel.org>

net: ice: Add xmo_rx_checksum callback

Adds the xmo_rx_checksum XDP metadata callback to the ice driver,
refactoring the existing checksum logic into a shared ice_get_rx_csum()
helper used by both the SKB and XDP paths.

> Implement xmo_rx_checksum callback in ice driver to report RX checksum
> result to the eBPF program bounded to the NIC.
> Introduce ice_get_rx_csum utility routine in order to rx cksum codebase
> available in ice_rx_csum().

This isn't a bug, but the second sentence appears to have missing words.
Should it read something like "in order to make the rx checksum code
reusable from ice_rx_csum()"?

---

AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

In-Reply-To-Subject: net: ice: Add xmo_rx_checksum callback
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/21992879200

AI-authorship-score: low
AI-authorship-explanation: Garbled commit message sentence and non-native English errors are characteristic of human authorship; AI tools typically produce grammatically correct output.
issues-found: 1
issue-severity-score: low
issue-severity-explanation: The only issue found is a garbled sentence in the commit message; no functional code regressions were identified.

[kernel-patches-daemon-bpf]

Forwarding comment 3897956689 via email
In-Reply-To: 20260213-bpf-xdp-meta-rxcksum-v2-1-a82c4802afbe@kernel.org
Patch: https://patchwork.kernel.org/project/netdevbpf/patch/20260213-bpf-xdp-meta-rxcksum-v2-1-a82c4802afbe@kernel.org/

[kernel-patches-daemon-bpf]

Forwarding comment 3897959462 via email
In-Reply-To: 20260213-bpf-xdp-meta-rxcksum-v2-2-a82c4802afbe@kernel.org
Patch: https://patchwork.kernel.org/project/netdevbpf/patch/20260213-bpf-xdp-meta-rxcksum-v2-2-a82c4802afbe@kernel.org/

[kernel-patches-daemon-bpf]

Forwarding comment 3897963748 via email
In-Reply-To: 20260213-bpf-xdp-meta-rxcksum-v2-3-a82c4802afbe@kernel.org
Patch: https://patchwork.kernel.org/project/netdevbpf/patch/20260213-bpf-xdp-meta-rxcksum-v2-3-a82c4802afbe@kernel.org/

[kernel-patches-daemon-bpf]

Upstream branch: f632de6
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1053970
version: 2

[kernel-patches-daemon-bpf]

Upstream branch: 4c51f90
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1053970
version: 2