On Wed, Oct 28, 2026 at 7:30 PM Stephen Hemminger <[email protected]> wrote: > > On Tue, 27 Oct 2026 18:21:13 +0000 > Tathagat Priyadarshi <[email protected]> wrote: > > > This series fixes transmit burst error handling and adds hardware TCP > > segmentation offload (TSO) for the Microsoft Azure MANA PMD. > > > > Patch 1 drops packets that fail validation, counting them in > > stats.errors and consuming them, so rte_eth_tx_burst() maintains a > > contiguous prefix and short returns reflect only ring backpressure. > > It also clamps segment limits to MAX_SGL_ENTRIES_FOR_TRANSMIT. > > > > Patch 2 implements hardware TSO for IPv4 and IPv6 TCP traffic, > > formatting SGE0 for headers and subsequent SGEs for payload, handling > > GDMA work request flags, advertising RTE_ETH_TX_OFFLOAD_TCP_TSO, and > > handling non-TSO fallback checksums. > > > > Hardware TSO segmentation was verified on Azure Standard_D8ds_v6 (kernel > > 6.8.0-1067-azure, MANA PCI 7870:00:00.0; driver reports no firmware > > version) between two VMs on one subnet using an earlier revision of > > this series: > > - VM A ran testpmd txonly, modified locally to emit TCP packets with > > RTE_MBUF_F_TX_TCP_SEG set (not part of this series), after > > "csum set ip hw 0", "csum set tcp hw 0" and "tso set 1460 0". > > - VM B captured the frames with tcpdump on its kernel interface, GRO off. > > - A 4000-byte IPv4 packet in a single mbuf, in mbufs with a header-only > > first segment, and in mbufs with payload in the first segment, each > > arrived as 1514, 1514 and 1080 byte frames with consecutive TCP > > sequence numbers, per-segment IP IDs and valid IP and TCP checksums. > > - Plain UDP with "tso set 0" was unaffected. > > - The drop paths (packets exceeding segment limit, oversized MSS or > > header) and IPv6 TSO were not exercised on hardware. > > > > The v3 changes (hardware field bounds for MSS and header length, > > loop bound, unsegmented fallback checksum masking, and dev_info limit > > advertisement) were compile-tested but have not been re-run on hardware. > > > > v3: > > - Patch 1: no changes. > > - Patch 2: > > * Mask RTE_MBUF_F_TX_TCP_SEG in the non-TSO fallback branch so > > rte_ipv4_phdr_cksum / rte_ipv6_phdr_cksum calculate the full L4 > > length into the pseudo-header checksum. > > * Reject invalid TSO packets (tso_segsz > MANA_TSO_MAX_SEGSZ or > > gso_hs > UINT8_MAX) to prevent hardware bitfield truncations. > > * Reflect the extra SGE for TSO in dev_info by setting nb_seg_max to > > max_sge - 1 (keeping nb_mtu_seg_max as max_sge) instead of a mana.rst > > limitation note. > > * Bound the TSO segment walk by expected_sge and verify SGE count. > > * Streamline commit message and cover letter. > > > > v2: > > - Patch 1: > > * Drop unsendable packets and return a separate consumed count (nb_done) > > instead of breaking out of the burst; break only when the ring is full. > > * Move MAX_SGL_ENTRIES_FOR_TRANSMIT clamp from patch 2 to patch 1, and > > clamp dev_info nb_seg_max and nb_mtu_seg_max. > > - Patch 2: > > * Use the drop path for all per-packet TSO validation failures. > > * Honour implied TCP checksum when RTE_MBUF_F_TX_TCP_SEG is set but the > > packet is unsegmented. > > * Move GDMA_WR_OOB_IN_SGL and GDMA_WR_PAD_BY_SGE0 adjacent to > > struct gdma_work_request. > > * Add release notes entry and update mana.ini feature matrix. > > > > Tathagat Priyadarshi (2): > > net/mana: fix transmit burst error handling > > net/mana: add hardware TSO support > > > > doc/guides/nics/features/mana.ini | 1 + > > doc/guides/rel_notes/release_26_11.rst | 4 + > > drivers/net/mana/gdma.c | 5 + > > drivers/net/mana/mana.c | 9 +- > > drivers/net/mana/mana.h | 9 +- > > drivers/net/mana/tx.c | 206 +++++++++++++++++++++---- > > 6 files changed, 195 insertions(+), 39 deletions(-) > > > > I can apply it as is. But you may want to look at the length issues > reported in AI review > > Subject: Re: [PATCH v3 0/2] net/mana: tx burst fixes and TSO > > Applied to main (e3e29ed), net/mana builds clean with -Dwerror=true > at each commit. Fixes: hashes verified. > > Patch 1 drops invalid packets and counts them in the returned value, > which is the right tx_burst contract. The SGL bound fix is correct. > No findings on patch 1. > > Patch 2 follows the Linux mana TSO path (header in SGE0, > OOB_IN_SGL | PAD_BY_SGE0, tot_len/payload_len zeroed, pseudo-header > seeded without length). Field widths match: last_v_bytes is 8 bits, > client_data_unit is 14 bits. > > [PATCH v3 2/2] net/mana: add hardware TSO support > > Info: l4_len is not validated. tcp_hdr->cksum is written at > l2_len + l3_len + 16, so with l4_len < 20 the write can land past > data_len, and SGE0 would split the TCP header. Cheap to reject: > > if (unlikely(m_pkt->l4_len < sizeof(struct rte_tcp_hdr) || > m_pkt->data_len < gso_hs || > gso_hs > UINT8_MAX)) { > > Info: total TSO length is not bounded. pkt_len can exceed 64K with > a long chain. If the hardware has a limit on TSO payload, check > pkt_len - gso_hs against it and drop. > > Info: the header fixups (IPv4 total_length/hdr_checksum, IPv6 > payload_len, TCP cksum) write into packet data from tx_burst. An > application holding a reference to the mbuf (e.g. for retransmit) > sees the modified headers. tx_pkt_prepare is the ethdev hook for > this; the existing checksum path already does the same thing, so > not a blocker for this series. > > Reviewed-by: Stephen Hemminger <[email protected]>
Hi Stephen, Thanks for the review and build verification! Please apply v3 as is. I'll send a separate patch for the l4_len validation. The TSO payload limit isn't documented, so I left it unbounded for now and will add a check if I find the hardware limit. I will also look into adding tx_pkt_prepare for MANA. If you'd rather have the l4_len change in a v4, let me know
