Date: Sun, 21 Dec 2025 14:46:37 +0000 From: Andrew Gallatin <gallatin@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 43d7ee540efe - main - iflib: support for transmit side nic KTLS offload Message-ID: <6948084d.3ae04.60ca348b@gitrepo.freebsd.org>
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The branch main has been updated by gallatin: URL: https://cgit.FreeBSD.org/src/commit/?id=43d7ee540efe0df1def80ce24255b32f9f9396ba commit 43d7ee540efe0df1def80ce24255b32f9f9396ba Author: Andrew Gallatin <gallatin@FreeBSD.org> AuthorDate: 2025-12-19 20:48:36 +0000 Commit: Andrew Gallatin <gallatin@FreeBSD.org> CommitDate: 2025-12-21 14:45:12 +0000 iflib: support for transmit side nic KTLS offload This change adds support to iflib for drivers that want to do transmit-side NIC ktls offload. This change does 2 things: 1) Extends the pkt info to include an optional mbuf pointer. This gives drivers the ability to find the start of a TLS record if they need to re-DMA part of the record to re-construct TLS state on the NIC. This mbuf pointer is only passed when CSUM_SND_TAG is present on the pkthdr. Note that I don't bother to inspect the send tag on purpose; this will only be present for TLS offloaded or paced connections 2) Allows the driver to specify how much ring padding is needed before the ring is considered to be full using the new isc_tx_pad field in if_softc_ctx. This re-uses a field that was marked spare in 2019 via d49e83eac3baf. Iflib initializes this to the previous value of 2 slots and allows the driver to override it. The TXQ_AVAIL() macro has been adjusted to subtract this padding, and uses of the macro have removed +2 from the other side of the comparison. To avoid potential cache misses from looking at the ifc_softc_ctx in TXQ_AVAIL(), the value is mirrored in the txq (in an alignment hole). Reviewed by: kbowling, kgalazka, sumit.saxena_broadcom.com, shurd Sponsored by: Netflix MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D54274 --- sys/net/iflib.c | 31 +++++++++++++++++++------------ sys/net/iflib.h | 5 +++-- 2 files changed, 22 insertions(+), 14 deletions(-) diff --git a/sys/net/iflib.c b/sys/net/iflib.c index 3181bdbcb849..bd0bfe4742df 100644 --- a/sys/net/iflib.c +++ b/sys/net/iflib.c @@ -375,6 +375,7 @@ struct iflib_txq { struct ifmp_ring *ift_br; struct grouptask ift_task; qidx_t ift_size; + qidx_t ift_pad; uint16_t ift_id; struct callout ift_timer; #ifdef DEV_NETMAP @@ -445,7 +446,8 @@ get_inuse(int size, qidx_t cidx, qidx_t pidx, uint8_t gen) return (used); } -#define TXQ_AVAIL(txq) (txq->ift_size - get_inuse(txq->ift_size, txq->ift_cidx, txq->ift_pidx, txq->ift_gen)) +#define TXQ_AVAIL(txq) ((txq->ift_size - txq->ift_pad) -\ + get_inuse(txq->ift_size, txq->ift_cidx, txq->ift_pidx, txq->ift_gen)) #define IDXDIFF(head, tail, wrap) \ ((head) >= (tail) ? (head) - (tail) : (wrap) - (tail) + (head)) @@ -485,11 +487,11 @@ typedef struct if_rxsd { /* multiple of word size */ #ifdef __LP64__ -#define PKT_INFO_SIZE 6 +#define PKT_INFO_SIZE 7 #define RXD_INFO_SIZE 5 #define PKT_TYPE uint64_t #else -#define PKT_INFO_SIZE 11 +#define PKT_INFO_SIZE 12 #define RXD_INFO_SIZE 8 #define PKT_TYPE uint32_t #endif @@ -1933,6 +1935,7 @@ iflib_txq_setup(iflib_txq_t txq) txq->ift_cidx_processed = 0; txq->ift_pidx = txq->ift_cidx = txq->ift_npending = 0; txq->ift_size = scctx->isc_ntxd[txq->ift_br_offset]; + txq->ift_pad = scctx->isc_tx_pad; for (i = 0, di = txq->ift_ifdi; i < sctx->isc_ntxqs; i++, di++) bzero((void *)di->idi_vaddr, di->idi_size); @@ -3100,7 +3103,7 @@ iflib_txd_db_check(iflib_txq_t txq, int ring) max = TXQ_MAX_DB_DEFERRED(txq, txq->ift_in_use); /* force || threshold exceeded || at the edge of the ring */ - if (ring || (txq->ift_db_pending >= max) || (TXQ_AVAIL(txq) <= MAX_TX_DESC(ctx) + 2)) { + if (ring || (txq->ift_db_pending >= max) || (TXQ_AVAIL(txq) <= MAX_TX_DESC(ctx))) { /* * 'npending' is used if the card's doorbell is in terms of the number of descriptors @@ -3604,14 +3607,18 @@ defrag: return (err); } ifsd_m[pidx] = m_head; + if (m_head->m_pkthdr.csum_flags & CSUM_SND_TAG) + pi.ipi_mbuf = m_head; + else + pi.ipi_mbuf = NULL; /* * XXX assumes a 1 to 1 relationship between segments and * descriptors - this does not hold true on all drivers, e.g. * cxgb */ - if (__predict_false(nsegs + 2 > TXQ_AVAIL(txq))) { + if (__predict_false(nsegs > TXQ_AVAIL(txq))) { (void)iflib_completed_tx_reclaim(txq); - if (__predict_false(nsegs + 2 > TXQ_AVAIL(txq))) { + if (__predict_false(nsegs > TXQ_AVAIL(txq))) { txq->ift_no_desc_avail++; bus_dmamap_unload(buf_tag, map); DBG_COUNTER_INC(encap_txq_avail_fail); @@ -3635,7 +3642,7 @@ defrag: */ txq->ift_rs_pending += nsegs + 1; if (txq->ift_rs_pending > TXQ_MAX_RS_DEFERRED(txq) || - iflib_no_tx_batch || (TXQ_AVAIL(txq) - nsegs) <= MAX_TX_DESC(ctx) + 2) { + iflib_no_tx_batch || (TXQ_AVAIL(txq) - nsegs) <= MAX_TX_DESC(ctx)) { pi.ipi_flags |= IPI_TX_INTR; txq->ift_rs_pending = 0; } @@ -3658,10 +3665,9 @@ defrag: txq->ift_gen = 1; } /* - * drivers can need as many as - * two sentinels + * drivers can need up to ift_pad sentinels */ - MPASS(ndesc <= pi.ipi_nsegs + 2); + MPASS(ndesc <= pi.ipi_nsegs + txq->ift_pad); MPASS(pi.ipi_new_pidx != pidx); MPASS(ndesc > 0); txq->ift_in_use += ndesc; @@ -3816,7 +3822,7 @@ iflib_txq_can_drain(struct ifmp_ring *r) iflib_txq_t txq = r->cookie; if_ctx_t ctx = txq->ift_ctx; - if (TXQ_AVAIL(txq) > MAX_TX_DESC(ctx) + 2) + if (TXQ_AVAIL(txq) > MAX_TX_DESC(ctx)) return (1); bus_dmamap_sync(txq->ift_ifdi->idi_tag, txq->ift_ifdi->idi_map, BUS_DMASYNC_POSTREAD); @@ -3880,7 +3886,7 @@ iflib_txq_drain(struct ifmp_ring *r, uint32_t cidx, uint32_t pidx) #endif do_prefetch = (ctx->ifc_flags & IFC_PREFETCH); err = 0; - for (i = 0; i < count && TXQ_AVAIL(txq) >= MAX_TX_DESC(ctx) + 2; i++) { + for (i = 0; i < count && TXQ_AVAIL(txq) >= MAX_TX_DESC(ctx); i++) { int rem = do_prefetch ? count - i : 0; mp = _ring_peek_one(r, cidx, i, rem); @@ -4740,6 +4746,7 @@ iflib_reset_qvalues(if_ctx_t ctx) scctx->isc_ntxd[i] = sctx->isc_ntxd_default[i]; } } + scctx->isc_tx_pad = 2; } static void diff --git a/sys/net/iflib.h b/sys/net/iflib.h index e65c936fc4b4..fe70fc5775cd 100644 --- a/sys/net/iflib.h +++ b/sys/net/iflib.h @@ -127,7 +127,8 @@ typedef struct if_pkt_info { uint8_t ipi_ip_tos; /* IP ToS field data */ uint8_t ipi_mflags; /* packet mbuf flags */ uint8_t __spare0__; - uint8_t __spare1__; + uint8_t __spare1__; + struct mbuf *ipi_mbuf; /* mbuf for ktls */ } *if_pkt_info_t; typedef struct if_irq { @@ -191,7 +192,7 @@ typedef struct if_softc_ctx { int isc_vectors; int isc_nrxqsets; int isc_ntxqsets; - uint16_t __spare0__; + uint16_t isc_tx_pad; uint32_t __spare1__; int isc_msix_bar; /* can be model specific - initialize in attach_pre */ int isc_tx_nsegments; /* can be model specific - initialize in attach_pre */help
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