[PATCH net-next v2 0/6] eth: mpnic: checksum and segmentation offloads

[Daniel Zahka <daniel.zahka@gmail.com>]

Add checksum and segmentation offload support. Tx checksum offload
follows the generic csum_start/csum_offset model. Rx checksum also
follows the normal unnecessary/complete model. The device can validate l4
checksums for tcp or udp, when the l3 type is one of: ipv4, ipv6,
ipv4-in-ipv6, or ipv6-in-ipv6. The full l2 checksum of a frame is always
passed to driver via a Rx completion descriptor field, which can be used
for checksum complete on other packet types.

Tx segmentation supports tcp or udp in ipv4, ipv6, 4-in-6, or 6-in-6
natively, and can support most other tunnels with GSO_PARTIAL.

Counters for CSO/LSO are exported via the netdev qstats API.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
Changes in v2:
- eth: mpnic: Tx checksum offload
  - use skb_network_offset() for the L2 header length in
    mpnic_features_check(), since the mac header is not yet set when
    called from the IP GSO slow path
  - also enable Tx checksum offload for encapsulated packets via
    hw_enc_features (moved from the IPv4 and IPv6 in IPv6 patch)
- eth: mpnic: Rx checksum offload
  - convert l2_csum with cpu_to_le16() before csum_unfold(), since the
    device reports it in network byte order and skb->csum was wrong on
    big-endian hosts
- eth: mpnic: TCP segmentation offload
  - count discarded skbs rather than segments in twq.dropped, matching
    the xmit error path and the core's tx_dropped
  - report only hw_gso_wire_packets; drop the super-packet counter
- eth: mpnic: UDP segmentation offload
  - fall back to SW GSO for skbs shorter than MPNIC_MIN_FRAME_LEN, since
    HW LSO would segment the zero padding as payload
- eth: mpnic: IPv4 and IPv6 in IPv6 tunnel segmentation
  - derive inner L3 header length from csum_start rather than
    inner_transport_header, which can be stale for DODGY skbs
  - check the outer header is IPv6 in mpnic_ipxip6_gso_ok(), since
    SKB_GSO_IPXIP6 can be set by a nested tunnel under an IPv4 outer
  - move hw_enc_features setup to the Tx checksum offload patch
- eth: mpnic: add GSO_PARTIAL for other tunnels
  - derive the L3 header length from csum_start rather than
    inner_transport_header, matching mpnic_features_check() and
    mpnic_tx_lso()
- Link to v1: https://lore.kernel.org/r/20261106-mpnic-lso-v1-0-e943ff1493e4@gmail.com

---
Daniel Zahka (6):
      eth: mpnic: Tx checksum offload
      eth: mpnic: Rx checksum offload
      eth: mpnic: TCP segmentation offload
      eth: mpnic: UDP segmentation offload
      eth: mpnic: IPv4 and IPv6 in IPv6 tunnel segmentation
      eth: mpnic: add GSO_PARTIAL for other tunnels

 drivers/net/ethernet/meta/mpnic/mpnic_csr.h    |  41 +++++
 drivers/net/ethernet/meta/mpnic/mpnic_init.c   |  14 ++
 drivers/net/ethernet/meta/mpnic/mpnic_netdev.c |  40 +++-
 drivers/net/ethernet/meta/mpnic/mpnic_netdev.h |   5 +
 drivers/net/ethernet/meta/mpnic/mpnic_txrx.c   | 242 ++++++++++++++++++++++++-
 drivers/net/ethernet/meta/mpnic/mpnic_txrx.h   |   8 +
 6 files changed, 346 insertions(+), 4 deletions(-)
---
base-commit: 97ced2c090bfc2156db31fca9f52cf253e4bc186
change-id: 20261102-mpnic-lso-19aeb38e5648

Best regards,
-- 
Daniel Zahka <daniel.zahka@gmail.com>