From: jan <jan@openbsd.org>
Date: Thu, 19 Oct 2023 16:28:02 +0000 (+0000)
Subject: Enable TCP Segmentation Offloading for ixl(4)
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=f77c9c95a26a7216ecbd417046c41383cd030d5b;p=openbsd

Enable TCP Segmentation Offloading for ixl(4)

Tested on amd64 and sparc64.
Also tested by bluhm@.

ok bluhm@
---

diff --git a/sys/dev/pci/if_ixl.c b/sys/dev/pci/if_ixl.c
index 7faa27c1929..07eb9db2f26 100644
--- a/sys/dev/pci/if_ixl.c
+++ b/sys/dev/pci/if_ixl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ixl.c,v 1.89 2023/09/29 19:44:47 bluhm Exp $ */
+/*	$OpenBSD: if_ixl.c,v 1.90 2023/10/19 16:28:02 jan Exp $ */
 
 /*
  * Copyright (c) 2013-2015, Intel Corporation
@@ -71,6 +71,7 @@
 #include <net/if.h>
 #include <net/if_dl.h>
 #include <net/if_media.h>
+#include <net/route.h>
 #include <net/toeplitz.h>
 
 #if NBPFILTER > 0
@@ -85,6 +86,8 @@
 #include <netinet/ip.h>
 #include <netinet/ip6.h>
 #include <netinet/tcp.h>
+#include <netinet/tcp_timer.h>
+#include <netinet/tcp_var.h>
 #include <netinet/udp.h>
 #include <netinet/if_ether.h>
 
@@ -827,6 +830,10 @@ struct ixl_tx_desc {
 #define IXL_TX_DESC_BSIZE_MASK		\
 	(IXL_TX_DESC_BSIZE_MAX << IXL_TX_DESC_BSIZE_SHIFT)
 
+#define IXL_TX_CTX_DESC_CMD_TSO		0x10
+#define IXL_TX_CTX_DESC_TLEN_SHIFT	30
+#define IXL_TX_CTX_DESC_MSS_SHIFT	50
+
 #define IXL_TX_DESC_L2TAG1_SHIFT	48
 } __packed __aligned(16);
 
@@ -893,11 +900,19 @@ struct ixl_rx_wb_desc_32 {
 	uint64_t		qword3;
 } __packed __aligned(16);
 
-#define IXL_TX_PKT_DESCS		8
+#define IXL_TX_PKT_DESCS		32
 #define IXL_TX_QUEUE_ALIGN		128
 #define IXL_RX_QUEUE_ALIGN		128
 
 #define IXL_HARDMTU			9712 /* 9726 - ETHER_HDR_LEN */
+#define IXL_TSO_SIZE			((255 * 1024) - 1)
+#define IXL_MAX_DMA_SEG_SIZE		((16 * 1024) - 1)
+
+/*
+ * Our TCP/IP Stack could not handle packets greater than MAXMCLBYTES.
+ * This interface could not handle packets greater than IXL_TSO_SIZE.
+ */
+CTASSERT(MAXMCLBYTES < IXL_TSO_SIZE);
 
 #define IXL_PCIREG			PCI_MAPREG_START
 
@@ -1958,6 +1973,7 @@ ixl_attach(struct device *parent, struct device *self, void *aux)
 	ifp->if_capabilities |= IFCAP_CSUM_IPv4 |
 	    IFCAP_CSUM_TCPv4 | IFCAP_CSUM_UDPv4 |
 	    IFCAP_CSUM_TCPv6 | IFCAP_CSUM_UDPv6;
+	ifp->if_capabilities |= IFCAP_TSOv4 | IFCAP_TSOv6;
 
 	ifmedia_init(&sc->sc_media, 0, ixl_media_change, ixl_media_status);
 
@@ -2603,7 +2619,7 @@ ixl_txr_alloc(struct ixl_softc *sc, unsigned int qid)
 		txm = &maps[i];
 
 		if (bus_dmamap_create(sc->sc_dmat,
-		    IXL_HARDMTU, IXL_TX_PKT_DESCS, IXL_HARDMTU, 0,
+		    MAXMCLBYTES, IXL_TX_PKT_DESCS, IXL_MAX_DMA_SEG_SIZE, 0,
 		    BUS_DMA_WAITOK | BUS_DMA_ALLOCNOW | BUS_DMA_64BIT,
 		    &txm->txm_map) != 0)
 			goto uncreate;
@@ -2787,7 +2803,8 @@ ixl_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m)
 }
 
 static uint64_t
-ixl_tx_setup_offload(struct mbuf *m0)
+ixl_tx_setup_offload(struct mbuf *m0, struct ixl_tx_ring *txr,
+    unsigned int prod)
 {
 	struct ether_extracted ext;
 	uint64_t hlen;
@@ -2800,7 +2817,7 @@ ixl_tx_setup_offload(struct mbuf *m0)
 	}
 
 	if (!ISSET(m0->m_pkthdr.csum_flags,
-	    M_IPV4_CSUM_OUT|M_TCP_CSUM_OUT|M_UDP_CSUM_OUT))
+	    M_IPV4_CSUM_OUT|M_TCP_CSUM_OUT|M_UDP_CSUM_OUT|M_TCP_TSO))
 		return (offload);
 
 	ether_extract_headers(m0, &ext);
@@ -2833,6 +2850,28 @@ ixl_tx_setup_offload(struct mbuf *m0)
 		offload |= (sizeof(*ext.udp) >> 2) << IXL_TX_DESC_L4LEN_SHIFT;
 	}
 
+	if (ISSET(m0->m_pkthdr.csum_flags, M_TCP_TSO)) {
+		if (ext.tcp) {
+			struct ixl_tx_desc *ring, *txd;
+			uint64_t cmd = 0;
+
+			hlen += ext.tcp->th_off << 2;
+			ring = IXL_DMA_KVA(&txr->txr_mem);
+			txd = &ring[prod];
+
+			cmd |= IXL_TX_DESC_DTYPE_CONTEXT;
+			cmd |= IXL_TX_CTX_DESC_CMD_TSO;
+			cmd |= (uint64_t)(m0->m_pkthdr.len - ETHER_HDR_LEN
+			    - hlen) << IXL_TX_CTX_DESC_TLEN_SHIFT;
+			cmd |= (uint64_t)(m0->m_pkthdr.ph_mss)
+			    << IXL_TX_CTX_DESC_MSS_SHIFT;
+
+			htolem64(&txd->addr, 0);
+			htolem64(&txd->cmd, cmd);
+		} else
+			tcpstat_inc(tcps_outbadtso);
+	}
+
 	return (offload);
 }
 
@@ -2873,7 +2912,8 @@ ixl_start(struct ifqueue *ifq)
 	mask = sc->sc_tx_ring_ndescs - 1;
 
 	for (;;) {
-		if (free <= IXL_TX_PKT_DESCS) {
+		/* We need one extra descriptor for TSO packets. */
+		if (free <= (IXL_TX_PKT_DESCS + 1)) {
 			ifq_set_oactive(ifq);
 			break;
 		}
@@ -2882,11 +2922,17 @@ ixl_start(struct ifqueue *ifq)
 		if (m == NULL)
 			break;
 
-		offload = ixl_tx_setup_offload(m);
+		offload = ixl_tx_setup_offload(m, txr, prod);
 
 		txm = &txr->txr_maps[prod];
 		map = txm->txm_map;
 
+		if (ISSET(m->m_pkthdr.csum_flags, M_TCP_TSO)) {
+			prod++;
+			prod &= mask;
+			free--;
+		}
+
 		if (ixl_load_mbuf(sc->sc_dmat, map, m) != 0) {
 			ifq->ifq_errors++;
 			m_freem(m);