Re: [PATCH net-next V4 14/14] selftests: drv-net: Add PSP HW GRO conformance tests

[Daniel Zahka]

On Tue Sep 8, 2026 at 2:52 AM EDT, Tariq Toukan wrote:
> From: Cosmin Ratiu <cratiu@xxxxxxxxxx>
>
> Add PSP conformance tests using the same gro helper binary as other gro
> tests , but in --psp mode. SPIs are procured by psp_gro.py from a real
> PSP device and handed off to the gro sender & receiver. The sender
> crafts and encrypts packets in software, the receiver relies fully on
> the HW to decrypt, decapsulate and do HW GRO.
>
> Because the NIC decrypts and decapsulates before the frames reach the
> receiver AF_PACKET tap, the gro receiver sees the plain frames and the
> assertions remain exactly the same as other gro tests.
>
> So these tests verify, at length, that the device does PSP HW-GRO the
> same way as plain TCP.
>
> Additional PSP-specific tests are defined to check that GRO doesn't
> merge packets across PSP versions, SPIs, encryption-status, etc.
>
> Some gro tests are not included because they don't work:
> - ip_csum: the checksum is recomputed by psp_dev_rcv().

psp_dev_rcv() isn't on the hw gro path for mlx5, right?

> - tcp_csum: packets are marked with CHECKSUM_UNNECESSARY.

this also seems strange to me as the hw gro engine and its decision to
coalesce two packets sits upstream of this skb->ip_summed determination
in the driver, right?

> - ip_frag4/ip_frag6: PSP is incompatible with IP fragmentation.
> - IPv6 extension header tests: PSP doesn't deal with IPv6 ext headers.
>
> Signed-off-by: Cosmin Ratiu <cratiu@xxxxxxxxxx>
> Reviewed-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
> ---
...
> +
> +@ksft_variants(_ip_variants())
> +def test_psp_ver_diff(cfg, protocol):
> +    """Frames from two different PSP versions must not coalesce."""
> +    init_psp_dev(cfg)
> +    if len(cfg.psp_info['psp-versions-cap']) < 2:

nit: what the above checks is slightly different than what the _run()
below uses, e.g. dev supports versions 0 and 2.

> +        raise KsftSkipEx("Device supports a single PSP version")
> +
> +    _run(cfg, "psp_ver_diff", protocol, [0, 1])
> +

couple of minor comments:

Reviewed-by: Daniel Zahka <daniel.zahka@xxxxxxxxx>