Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1813 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sun/sunvnet_common.c b/drivers/net/ethernet/sun/sunvnet_common.c
new file mode 100644
index 000000000..80fde5f06
--- /dev/null
+++ b/drivers/net/ethernet/sun/sunvnet_common.c
@@ -0,0 +1,1813 @@
+// SPDX-License-Identifier: GPL-2.0
+/* sunvnet.c: Sun LDOM Virtual Network Driver.
+ *
+ * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
+ * Copyright (C) 2016-2017 Oracle. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/ethtool.h>
+#include <linux/etherdevice.h>
+#include <linux/mutex.h>
+#include <linux/highmem.h>
+#include <linux/if_vlan.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/sunvnet.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <linux/icmpv6.h>
+#endif
+
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/route.h>
+
+#include <asm/vio.h>
+#include <asm/ldc.h>
+
+#include "sunvnet_common.h"
+
+/* Heuristic for the number of times to exponentially backoff and
+ * retry sending an LDC trigger when EAGAIN is encountered
+ */
+#define	VNET_MAX_RETRIES	10
+
+MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
+MODULE_DESCRIPTION("Sun LDOM virtual network support library");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.1");
+
+static int __vnet_tx_trigger(struct vnet_port *port, u32 start);
+
+static inline u32 vnet_tx_dring_avail(struct vio_dring_state *dr)
+{
+	return vio_dring_avail(dr, VNET_TX_RING_SIZE);
+}
+
+static int vnet_handle_unknown(struct vnet_port *port, void *arg)
+{
+	struct vio_msg_tag *pkt = arg;
+
+	pr_err("Received unknown msg [%02x:%02x:%04x:%08x]\n",
+	       pkt->type, pkt->stype, pkt->stype_env, pkt->sid);
+	pr_err("Resetting connection\n");
+
+	ldc_disconnect(port->vio.lp);
+
+	return -ECONNRESET;
+}
+
+static int vnet_port_alloc_tx_ring(struct vnet_port *port);
+
+int sunvnet_send_attr_common(struct vio_driver_state *vio)
+{
+	struct vnet_port *port = to_vnet_port(vio);
+	struct net_device *dev = VNET_PORT_TO_NET_DEVICE(port);
+	struct vio_net_attr_info pkt;
+	int framelen = ETH_FRAME_LEN;
+	int i, err;
+
+	err = vnet_port_alloc_tx_ring(to_vnet_port(vio));
+	if (err)
+		return err;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.tag.type = VIO_TYPE_CTRL;
+	pkt.tag.stype = VIO_SUBTYPE_INFO;
+	pkt.tag.stype_env = VIO_ATTR_INFO;
+	pkt.tag.sid = vio_send_sid(vio);
+	if (vio_version_before(vio, 1, 2))
+		pkt.xfer_mode = VIO_DRING_MODE;
+	else
+		pkt.xfer_mode = VIO_NEW_DRING_MODE;
+	pkt.addr_type = VNET_ADDR_ETHERMAC;
+	pkt.ack_freq = 0;
+	for (i = 0; i < 6; i++)
+		pkt.addr |= (u64)dev->dev_addr[i] << ((5 - i) * 8);
+	if (vio_version_after(vio, 1, 3)) {
+		if (port->rmtu) {
+			port->rmtu = min(VNET_MAXPACKET, port->rmtu);
+			pkt.mtu = port->rmtu;
+		} else {
+			port->rmtu = VNET_MAXPACKET;
+			pkt.mtu = port->rmtu;
+		}
+		if (vio_version_after_eq(vio, 1, 6))
+			pkt.options = VIO_TX_DRING;
+	} else if (vio_version_before(vio, 1, 3)) {
+		pkt.mtu = framelen;
+	} else { /* v1.3 */
+		pkt.mtu = framelen + VLAN_HLEN;
+	}
+
+	pkt.cflags = 0;
+	if (vio_version_after_eq(vio, 1, 7) && port->tso) {
+		pkt.cflags |= VNET_LSO_IPV4_CAPAB;
+		if (!port->tsolen)
+			port->tsolen = VNET_MAXTSO;
+		pkt.ipv4_lso_maxlen = port->tsolen;
+	}
+
+	pkt.plnk_updt = PHYSLINK_UPDATE_NONE;
+
+	viodbg(HS, "SEND NET ATTR xmode[0x%x] atype[0x%x] addr[%llx] "
+	       "ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] mtu[%llu] "
+	       "cflags[0x%04x] lso_max[%u]\n",
+	       pkt.xfer_mode, pkt.addr_type,
+	       (unsigned long long)pkt.addr,
+	       pkt.ack_freq, pkt.plnk_updt, pkt.options,
+	       (unsigned long long)pkt.mtu, pkt.cflags, pkt.ipv4_lso_maxlen);
+
+	return vio_ldc_send(vio, &pkt, sizeof(pkt));
+}
+EXPORT_SYMBOL_GPL(sunvnet_send_attr_common);
+
+static int handle_attr_info(struct vio_driver_state *vio,
+			    struct vio_net_attr_info *pkt)
+{
+	struct vnet_port *port = to_vnet_port(vio);
+	u64	localmtu;
+	u8	xfer_mode;
+
+	viodbg(HS, "GOT NET ATTR xmode[0x%x] atype[0x%x] addr[%llx] "
+	       "ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] mtu[%llu] "
+	       " (rmtu[%llu]) cflags[0x%04x] lso_max[%u]\n",
+	       pkt->xfer_mode, pkt->addr_type,
+	       (unsigned long long)pkt->addr,
+	       pkt->ack_freq, pkt->plnk_updt, pkt->options,
+	       (unsigned long long)pkt->mtu, port->rmtu, pkt->cflags,
+	       pkt->ipv4_lso_maxlen);
+
+	pkt->tag.sid = vio_send_sid(vio);
+
+	xfer_mode = pkt->xfer_mode;
+	/* for version < 1.2, VIO_DRING_MODE = 0x3 and no bitmask */
+	if (vio_version_before(vio, 1, 2) && xfer_mode == VIO_DRING_MODE)
+		xfer_mode = VIO_NEW_DRING_MODE;
+
+	/* MTU negotiation:
+	 *	< v1.3 - ETH_FRAME_LEN exactly
+	 *	> v1.3 - MIN(pkt.mtu, VNET_MAXPACKET, port->rmtu) and change
+	 *			pkt->mtu for ACK
+	 *	= v1.3 - ETH_FRAME_LEN + VLAN_HLEN exactly
+	 */
+	if (vio_version_before(vio, 1, 3)) {
+		localmtu = ETH_FRAME_LEN;
+	} else if (vio_version_after(vio, 1, 3)) {
+		localmtu = port->rmtu ? port->rmtu : VNET_MAXPACKET;
+		localmtu = min(pkt->mtu, localmtu);
+		pkt->mtu = localmtu;
+	} else { /* v1.3 */
+		localmtu = ETH_FRAME_LEN + VLAN_HLEN;
+	}
+	port->rmtu = localmtu;
+
+	/* LSO negotiation */
+	if (vio_version_after_eq(vio, 1, 7))
+		port->tso &= !!(pkt->cflags & VNET_LSO_IPV4_CAPAB);
+	else
+		port->tso = false;
+	if (port->tso) {
+		if (!port->tsolen)
+			port->tsolen = VNET_MAXTSO;
+		port->tsolen = min(port->tsolen, pkt->ipv4_lso_maxlen);
+		if (port->tsolen < VNET_MINTSO) {
+			port->tso = false;
+			port->tsolen = 0;
+			pkt->cflags &= ~VNET_LSO_IPV4_CAPAB;
+		}
+		pkt->ipv4_lso_maxlen = port->tsolen;
+	} else {
+		pkt->cflags &= ~VNET_LSO_IPV4_CAPAB;
+		pkt->ipv4_lso_maxlen = 0;
+		port->tsolen = 0;
+	}
+
+	/* for version >= 1.6, ACK packet mode we support */
+	if (vio_version_after_eq(vio, 1, 6)) {
+		pkt->xfer_mode = VIO_NEW_DRING_MODE;
+		pkt->options = VIO_TX_DRING;
+	}
+
+	if (!(xfer_mode | VIO_NEW_DRING_MODE) ||
+	    pkt->addr_type != VNET_ADDR_ETHERMAC ||
+	    pkt->mtu != localmtu) {
+		viodbg(HS, "SEND NET ATTR NACK\n");
+
+		pkt->tag.stype = VIO_SUBTYPE_NACK;
+
+		(void)vio_ldc_send(vio, pkt, sizeof(*pkt));
+
+		return -ECONNRESET;
+	}
+
+	viodbg(HS, "SEND NET ATTR ACK xmode[0x%x] atype[0x%x] "
+	       "addr[%llx] ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] "
+	       "mtu[%llu] (rmtu[%llu]) cflags[0x%04x] lso_max[%u]\n",
+	       pkt->xfer_mode, pkt->addr_type,
+	       (unsigned long long)pkt->addr,
+	       pkt->ack_freq, pkt->plnk_updt, pkt->options,
+	       (unsigned long long)pkt->mtu, port->rmtu, pkt->cflags,
+	       pkt->ipv4_lso_maxlen);
+
+	pkt->tag.stype = VIO_SUBTYPE_ACK;
+
+	return vio_ldc_send(vio, pkt, sizeof(*pkt));
+}
+
+static int handle_attr_ack(struct vio_driver_state *vio,
+			   struct vio_net_attr_info *pkt)
+{
+	viodbg(HS, "GOT NET ATTR ACK\n");
+
+	return 0;
+}
+
+static int handle_attr_nack(struct vio_driver_state *vio,
+			    struct vio_net_attr_info *pkt)
+{
+	viodbg(HS, "GOT NET ATTR NACK\n");
+
+	return -ECONNRESET;
+}
+
+int sunvnet_handle_attr_common(struct vio_driver_state *vio, void *arg)
+{
+	struct vio_net_attr_info *pkt = arg;
+
+	switch (pkt->tag.stype) {
+	case VIO_SUBTYPE_INFO:
+		return handle_attr_info(vio, pkt);
+
+	case VIO_SUBTYPE_ACK:
+		return handle_attr_ack(vio, pkt);
+
+	case VIO_SUBTYPE_NACK:
+		return handle_attr_nack(vio, pkt);
+
+	default:
+		return -ECONNRESET;
+	}
+}
+EXPORT_SYMBOL_GPL(sunvnet_handle_attr_common);
+
+void sunvnet_handshake_complete_common(struct vio_driver_state *vio)
+{
+	struct vio_dring_state *dr;
+
+	dr = &vio->drings[VIO_DRIVER_RX_RING];
+	dr->rcv_nxt = 1;
+	dr->snd_nxt = 1;
+
+	dr = &vio->drings[VIO_DRIVER_TX_RING];
+	dr->rcv_nxt = 1;
+	dr->snd_nxt = 1;
+}
+EXPORT_SYMBOL_GPL(sunvnet_handshake_complete_common);
+
+/* The hypervisor interface that implements copying to/from imported
+ * memory from another domain requires that copies are done to 8-byte
+ * aligned buffers, and that the lengths of such copies are also 8-byte
+ * multiples.
+ *
+ * So we align skb->data to an 8-byte multiple and pad-out the data
+ * area so we can round the copy length up to the next multiple of
+ * 8 for the copy.
+ *
+ * The transmitter puts the actual start of the packet 6 bytes into
+ * the buffer it sends over, so that the IP headers after the ethernet
+ * header are aligned properly.  These 6 bytes are not in the descriptor
+ * length, they are simply implied.  This offset is represented using
+ * the VNET_PACKET_SKIP macro.
+ */
+static struct sk_buff *alloc_and_align_skb(struct net_device *dev,
+					   unsigned int len)
+{
+	struct sk_buff *skb;
+	unsigned long addr, off;
+
+	skb = netdev_alloc_skb(dev, len + VNET_PACKET_SKIP + 8 + 8);
+	if (unlikely(!skb))
+		return NULL;
+
+	addr = (unsigned long)skb->data;
+	off = ((addr + 7UL) & ~7UL) - addr;
+	if (off)
+		skb_reserve(skb, off);
+
+	return skb;
+}
+
+static inline void vnet_fullcsum_ipv4(struct sk_buff *skb)
+{
+	struct iphdr *iph = ip_hdr(skb);
+	int offset = skb_transport_offset(skb);
+
+	if (skb->protocol != htons(ETH_P_IP))
+		return;
+	if (iph->protocol != IPPROTO_TCP &&
+	    iph->protocol != IPPROTO_UDP)
+		return;
+	skb->ip_summed = CHECKSUM_NONE;
+	skb->csum_level = 1;
+	skb->csum = 0;
+	if (iph->protocol == IPPROTO_TCP) {
+		struct tcphdr *ptcp = tcp_hdr(skb);
+
+		ptcp->check = 0;
+		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		ptcp->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
+						skb->len - offset, IPPROTO_TCP,
+						skb->csum);
+	} else if (iph->protocol == IPPROTO_UDP) {
+		struct udphdr *pudp = udp_hdr(skb);
+
+		pudp->check = 0;
+		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		pudp->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
+						skb->len - offset, IPPROTO_UDP,
+						skb->csum);
+	}
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static inline void vnet_fullcsum_ipv6(struct sk_buff *skb)
+{
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	int offset = skb_transport_offset(skb);
+
+	if (skb->protocol != htons(ETH_P_IPV6))
+		return;
+	if (ip6h->nexthdr != IPPROTO_TCP &&
+	    ip6h->nexthdr != IPPROTO_UDP)
+		return;
+	skb->ip_summed = CHECKSUM_NONE;
+	skb->csum_level = 1;
+	skb->csum = 0;
+	if (ip6h->nexthdr == IPPROTO_TCP) {
+		struct tcphdr *ptcp = tcp_hdr(skb);
+
+		ptcp->check = 0;
+		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		ptcp->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+					      skb->len - offset, IPPROTO_TCP,
+					      skb->csum);
+	} else if (ip6h->nexthdr == IPPROTO_UDP) {
+		struct udphdr *pudp = udp_hdr(skb);
+
+		pudp->check = 0;
+		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		pudp->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+					      skb->len - offset, IPPROTO_UDP,
+					      skb->csum);
+	}
+}
+#endif
+
+static int vnet_rx_one(struct vnet_port *port, struct vio_net_desc *desc)
+{
+	struct net_device *dev = VNET_PORT_TO_NET_DEVICE(port);
+	unsigned int len = desc->size;
+	unsigned int copy_len;
+	struct sk_buff *skb;
+	int maxlen;
+	int err;
+
+	err = -EMSGSIZE;
+	if (port->tso && port->tsolen > port->rmtu)
+		maxlen = port->tsolen;
+	else
+		maxlen = port->rmtu;
+	if (unlikely(len < ETH_ZLEN || len > maxlen)) {
+		dev->stats.rx_length_errors++;
+		goto out_dropped;
+	}
+
+	skb = alloc_and_align_skb(dev, len);
+	err = -ENOMEM;
+	if (unlikely(!skb)) {
+		dev->stats.rx_missed_errors++;
+		goto out_dropped;
+	}
+
+	copy_len = (len + VNET_PACKET_SKIP + 7U) & ~7U;
+	skb_put(skb, copy_len);
+	err = ldc_copy(port->vio.lp, LDC_COPY_IN,
+		       skb->data, copy_len, 0,
+		       desc->cookies, desc->ncookies);
+	if (unlikely(err < 0)) {
+		dev->stats.rx_frame_errors++;
+		goto out_free_skb;
+	}
+
+	skb_pull(skb, VNET_PACKET_SKIP);
+	skb_trim(skb, len);
+	skb->protocol = eth_type_trans(skb, dev);
+
+	if (vio_version_after_eq(&port->vio, 1, 8)) {
+		struct vio_net_dext *dext = vio_net_ext(desc);
+
+		skb_reset_network_header(skb);
+
+		if (dext->flags & VNET_PKT_HCK_IPV4_HDRCKSUM) {
+			if (skb->protocol == ETH_P_IP) {
+				struct iphdr *iph = ip_hdr(skb);
+
+				iph->check = 0;
+				ip_send_check(iph);
+			}
+		}
+		if ((dext->flags & VNET_PKT_HCK_FULLCKSUM) &&
+		    skb->ip_summed == CHECKSUM_NONE) {
+			if (skb->protocol == htons(ETH_P_IP)) {
+				struct iphdr *iph = ip_hdr(skb);
+				int ihl = iph->ihl * 4;
+
+				skb_set_transport_header(skb, ihl);
+				vnet_fullcsum_ipv4(skb);
+#if IS_ENABLED(CONFIG_IPV6)
+			} else if (skb->protocol == htons(ETH_P_IPV6)) {
+				skb_set_transport_header(skb,
+							 sizeof(struct ipv6hdr));
+				vnet_fullcsum_ipv6(skb);
+#endif
+			}
+		}
+		if (dext->flags & VNET_PKT_HCK_IPV4_HDRCKSUM_OK) {
+			skb->ip_summed = CHECKSUM_PARTIAL;
+			skb->csum_level = 0;
+			if (dext->flags & VNET_PKT_HCK_FULLCKSUM_OK)
+				skb->csum_level = 1;
+		}
+	}
+
+	skb->ip_summed = port->switch_port ? CHECKSUM_NONE : CHECKSUM_PARTIAL;
+
+	if (unlikely(is_multicast_ether_addr(eth_hdr(skb)->h_dest)))
+		dev->stats.multicast++;
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += len;
+	port->stats.rx_packets++;
+	port->stats.rx_bytes += len;
+	napi_gro_receive(&port->napi, skb);
+	return 0;
+
+out_free_skb:
+	kfree_skb(skb);
+
+out_dropped:
+	dev->stats.rx_dropped++;
+	return err;
+}
+
+static int vnet_send_ack(struct vnet_port *port, struct vio_dring_state *dr,
+			 u32 start, u32 end, u8 vio_dring_state)
+{
+	struct vio_dring_data hdr = {
+		.tag = {
+			.type		= VIO_TYPE_DATA,
+			.stype		= VIO_SUBTYPE_ACK,
+			.stype_env	= VIO_DRING_DATA,
+			.sid		= vio_send_sid(&port->vio),
+		},
+		.dring_ident		= dr->ident,
+		.start_idx		= start,
+		.end_idx		= end,
+		.state			= vio_dring_state,
+	};
+	int err, delay;
+	int retries = 0;
+
+	hdr.seq = dr->snd_nxt;
+	delay = 1;
+	do {
+		err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
+		if (err > 0) {
+			dr->snd_nxt++;
+			break;
+		}
+		udelay(delay);
+		if ((delay <<= 1) > 128)
+			delay = 128;
+		if (retries++ > VNET_MAX_RETRIES) {
+			pr_info("ECONNRESET %x:%x:%x:%x:%x:%x\n",
+				port->raddr[0], port->raddr[1],
+				port->raddr[2], port->raddr[3],
+				port->raddr[4], port->raddr[5]);
+			break;
+		}
+	} while (err == -EAGAIN);
+
+	if (err <= 0 && vio_dring_state == VIO_DRING_STOPPED) {
+		port->stop_rx_idx = end;
+		port->stop_rx = true;
+	} else {
+		port->stop_rx_idx = 0;
+		port->stop_rx = false;
+	}
+
+	return err;
+}
+
+static struct vio_net_desc *get_rx_desc(struct vnet_port *port,
+					struct vio_dring_state *dr,
+					u32 index)
+{
+	struct vio_net_desc *desc = port->vio.desc_buf;
+	int err;
+
+	err = ldc_get_dring_entry(port->vio.lp, desc, dr->entry_size,
+				  (index * dr->entry_size),
+				  dr->cookies, dr->ncookies);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	return desc;
+}
+
+static int put_rx_desc(struct vnet_port *port,
+		       struct vio_dring_state *dr,
+		       struct vio_net_desc *desc,
+		       u32 index)
+{
+	int err;
+
+	err = ldc_put_dring_entry(port->vio.lp, desc, dr->entry_size,
+				  (index * dr->entry_size),
+				  dr->cookies, dr->ncookies);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int vnet_walk_rx_one(struct vnet_port *port,
+			    struct vio_dring_state *dr,
+			    u32 index, int *needs_ack)
+{
+	struct vio_net_desc *desc = get_rx_desc(port, dr, index);
+	struct vio_driver_state *vio = &port->vio;
+	int err;
+
+	BUG_ON(!desc);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	if (desc->hdr.state != VIO_DESC_READY)
+		return 1;
+
+	dma_rmb();
+
+	viodbg(DATA, "vio_walk_rx_one desc[%02x:%02x:%08x:%08x:%llx:%llx]\n",
+	       desc->hdr.state, desc->hdr.ack,
+	       desc->size, desc->ncookies,
+	       desc->cookies[0].cookie_addr,
+	       desc->cookies[0].cookie_size);
+
+	err = vnet_rx_one(port, desc);
+	if (err == -ECONNRESET)
+		return err;
+	trace_vnet_rx_one(port->vio._local_sid, port->vio._peer_sid,
+			  index, desc->hdr.ack);
+	desc->hdr.state = VIO_DESC_DONE;
+	err = put_rx_desc(port, dr, desc, index);
+	if (err < 0)
+		return err;
+	*needs_ack = desc->hdr.ack;
+	return 0;
+}
+
+static int vnet_walk_rx(struct vnet_port *port, struct vio_dring_state *dr,
+			u32 start, u32 end, int *npkts, int budget)
+{
+	struct vio_driver_state *vio = &port->vio;
+	int ack_start = -1, ack_end = -1;
+	bool send_ack = true;
+
+	end = (end == (u32)-1) ? vio_dring_prev(dr, start)
+			       : vio_dring_next(dr, end);
+
+	viodbg(DATA, "vnet_walk_rx start[%08x] end[%08x]\n", start, end);
+
+	while (start != end) {
+		int ack = 0, err = vnet_walk_rx_one(port, dr, start, &ack);
+
+		if (err == -ECONNRESET)
+			return err;
+		if (err != 0)
+			break;
+		(*npkts)++;
+		if (ack_start == -1)
+			ack_start = start;
+		ack_end = start;
+		start = vio_dring_next(dr, start);
+		if (ack && start != end) {
+			err = vnet_send_ack(port, dr, ack_start, ack_end,
+					    VIO_DRING_ACTIVE);
+			if (err == -ECONNRESET)
+				return err;
+			ack_start = -1;
+		}
+		if ((*npkts) >= budget) {
+			send_ack = false;
+			break;
+		}
+	}
+	if (unlikely(ack_start == -1)) {
+		ack_end = vio_dring_prev(dr, start);
+		ack_start = ack_end;
+	}
+	if (send_ack) {
+		port->napi_resume = false;
+		trace_vnet_tx_send_stopped_ack(port->vio._local_sid,
+					       port->vio._peer_sid,
+					       ack_end, *npkts);
+		return vnet_send_ack(port, dr, ack_start, ack_end,
+				     VIO_DRING_STOPPED);
+	} else  {
+		trace_vnet_tx_defer_stopped_ack(port->vio._local_sid,
+						port->vio._peer_sid,
+						ack_end, *npkts);
+		port->napi_resume = true;
+		port->napi_stop_idx = ack_end;
+		return 1;
+	}
+}
+
+static int vnet_rx(struct vnet_port *port, void *msgbuf, int *npkts,
+		   int budget)
+{
+	struct vio_dring_data *pkt = msgbuf;
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_RX_RING];
+	struct vio_driver_state *vio = &port->vio;
+
+	viodbg(DATA, "vnet_rx stype_env[%04x] seq[%016llx] rcv_nxt[%016llx]\n",
+	       pkt->tag.stype_env, pkt->seq, dr->rcv_nxt);
+
+	if (unlikely(pkt->tag.stype_env != VIO_DRING_DATA))
+		return 0;
+	if (unlikely(pkt->seq != dr->rcv_nxt)) {
+		pr_err("RX out of sequence seq[0x%llx] rcv_nxt[0x%llx]\n",
+		       pkt->seq, dr->rcv_nxt);
+		return 0;
+	}
+
+	if (!port->napi_resume)
+		dr->rcv_nxt++;
+
+	/* XXX Validate pkt->start_idx and pkt->end_idx XXX */
+
+	return vnet_walk_rx(port, dr, pkt->start_idx, pkt->end_idx,
+			    npkts, budget);
+}
+
+static int idx_is_pending(struct vio_dring_state *dr, u32 end)
+{
+	u32 idx = dr->cons;
+	int found = 0;
+
+	while (idx != dr->prod) {
+		if (idx == end) {
+			found = 1;
+			break;
+		}
+		idx = vio_dring_next(dr, idx);
+	}
+	return found;
+}
+
+static int vnet_ack(struct vnet_port *port, void *msgbuf)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct vio_dring_data *pkt = msgbuf;
+	struct net_device *dev;
+	u32 end;
+	struct vio_net_desc *desc;
+	struct netdev_queue *txq;
+
+	if (unlikely(pkt->tag.stype_env != VIO_DRING_DATA))
+		return 0;
+
+	end = pkt->end_idx;
+	dev = VNET_PORT_TO_NET_DEVICE(port);
+	netif_tx_lock(dev);
+	if (unlikely(!idx_is_pending(dr, end))) {
+		netif_tx_unlock(dev);
+		return 0;
+	}
+
+	/* sync for race conditions with vnet_start_xmit() and tell xmit it
+	 * is time to send a trigger.
+	 */
+	trace_vnet_rx_stopped_ack(port->vio._local_sid,
+				  port->vio._peer_sid, end);
+	dr->cons = vio_dring_next(dr, end);
+	desc = vio_dring_entry(dr, dr->cons);
+	if (desc->hdr.state == VIO_DESC_READY && !port->start_cons) {
+		/* vnet_start_xmit() just populated this dring but missed
+		 * sending the "start" LDC message to the consumer.
+		 * Send a "start" trigger on its behalf.
+		 */
+		if (__vnet_tx_trigger(port, dr->cons) > 0)
+			port->start_cons = false;
+		else
+			port->start_cons = true;
+	} else {
+		port->start_cons = true;
+	}
+	netif_tx_unlock(dev);
+
+	txq = netdev_get_tx_queue(dev, port->q_index);
+	if (unlikely(netif_tx_queue_stopped(txq) &&
+		     vnet_tx_dring_avail(dr) >= VNET_TX_WAKEUP_THRESH(dr)))
+		return 1;
+
+	return 0;
+}
+
+static int vnet_nack(struct vnet_port *port, void *msgbuf)
+{
+	/* XXX just reset or similar XXX */
+	return 0;
+}
+
+static int handle_mcast(struct vnet_port *port, void *msgbuf)
+{
+	struct vio_net_mcast_info *pkt = msgbuf;
+	struct net_device *dev = VNET_PORT_TO_NET_DEVICE(port);
+
+	if (pkt->tag.stype != VIO_SUBTYPE_ACK)
+		pr_err("%s: Got unexpected MCAST reply [%02x:%02x:%04x:%08x]\n",
+		       dev->name,
+		       pkt->tag.type,
+		       pkt->tag.stype,
+		       pkt->tag.stype_env,
+		       pkt->tag.sid);
+
+	return 0;
+}
+
+/* If the queue is stopped, wake it up so that we'll
+ * send out another START message at the next TX.
+ */
+static void maybe_tx_wakeup(struct vnet_port *port)
+{
+	struct netdev_queue *txq;
+
+	txq = netdev_get_tx_queue(VNET_PORT_TO_NET_DEVICE(port),
+				  port->q_index);
+	__netif_tx_lock(txq, smp_processor_id());
+	if (likely(netif_tx_queue_stopped(txq)))
+		netif_tx_wake_queue(txq);
+	__netif_tx_unlock(txq);
+}
+
+bool sunvnet_port_is_up_common(struct vnet_port *vnet)
+{
+	struct vio_driver_state *vio = &vnet->vio;
+
+	return !!(vio->hs_state & VIO_HS_COMPLETE);
+}
+EXPORT_SYMBOL_GPL(sunvnet_port_is_up_common);
+
+static int vnet_event_napi(struct vnet_port *port, int budget)
+{
+	struct net_device *dev = VNET_PORT_TO_NET_DEVICE(port);
+	struct vio_driver_state *vio = &port->vio;
+	int tx_wakeup, err;
+	int npkts = 0;
+
+	/* we don't expect any other bits */
+	BUG_ON(port->rx_event & ~(LDC_EVENT_DATA_READY |
+				  LDC_EVENT_RESET |
+				  LDC_EVENT_UP));
+
+	/* RESET takes precedent over any other event */
+	if (port->rx_event & LDC_EVENT_RESET) {
+		/* a link went down */
+
+		if (port->vsw == 1) {
+			netif_tx_stop_all_queues(dev);
+			netif_carrier_off(dev);
+		}
+
+		vio_link_state_change(vio, LDC_EVENT_RESET);
+		vnet_port_reset(port);
+		vio_port_up(vio);
+
+		/* If the device is running but its tx queue was
+		 * stopped (due to flow control), restart it.
+		 * This is necessary since vnet_port_reset()
+		 * clears the tx drings and thus we may never get
+		 * back a VIO_TYPE_DATA ACK packet - which is
+		 * the normal mechanism to restart the tx queue.
+		 */
+		if (netif_running(dev))
+			maybe_tx_wakeup(port);
+
+		port->rx_event = 0;
+		port->stats.event_reset++;
+		return 0;
+	}
+
+	if (port->rx_event & LDC_EVENT_UP) {
+		/* a link came up */
+
+		if (port->vsw == 1) {
+			netif_carrier_on(port->dev);
+			netif_tx_start_all_queues(port->dev);
+		}
+
+		vio_link_state_change(vio, LDC_EVENT_UP);
+		port->rx_event = 0;
+		port->stats.event_up++;
+		return 0;
+	}
+
+	err = 0;
+	tx_wakeup = 0;
+	while (1) {
+		union {
+			struct vio_msg_tag tag;
+			u64 raw[8];
+		} msgbuf;
+
+		if (port->napi_resume) {
+			struct vio_dring_data *pkt =
+				(struct vio_dring_data *)&msgbuf;
+			struct vio_dring_state *dr =
+				&port->vio.drings[VIO_DRIVER_RX_RING];
+
+			pkt->tag.type = VIO_TYPE_DATA;
+			pkt->tag.stype = VIO_SUBTYPE_INFO;
+			pkt->tag.stype_env = VIO_DRING_DATA;
+			pkt->seq = dr->rcv_nxt;
+			pkt->start_idx = vio_dring_next(dr,
+							port->napi_stop_idx);
+			pkt->end_idx = -1;
+		} else {
+			err = ldc_read(vio->lp, &msgbuf, sizeof(msgbuf));
+			if (unlikely(err < 0)) {
+				if (err == -ECONNRESET)
+					vio_conn_reset(vio);
+				break;
+			}
+			if (err == 0)
+				break;
+			viodbg(DATA, "TAG [%02x:%02x:%04x:%08x]\n",
+			       msgbuf.tag.type,
+			       msgbuf.tag.stype,
+			       msgbuf.tag.stype_env,
+			       msgbuf.tag.sid);
+			err = vio_validate_sid(vio, &msgbuf.tag);
+			if (err < 0)
+				break;
+		}
+
+		if (likely(msgbuf.tag.type == VIO_TYPE_DATA)) {
+			if (msgbuf.tag.stype == VIO_SUBTYPE_INFO) {
+				if (!sunvnet_port_is_up_common(port)) {
+					/* failures like handshake_failure()
+					 * may have cleaned up dring, but
+					 * NAPI polling may bring us here.
+					 */
+					err = -ECONNRESET;
+					break;
+				}
+				err = vnet_rx(port, &msgbuf, &npkts, budget);
+				if (npkts >= budget)
+					break;
+				if (npkts == 0)
+					break;
+			} else if (msgbuf.tag.stype == VIO_SUBTYPE_ACK) {
+				err = vnet_ack(port, &msgbuf);
+				if (err > 0)
+					tx_wakeup |= err;
+			} else if (msgbuf.tag.stype == VIO_SUBTYPE_NACK) {
+				err = vnet_nack(port, &msgbuf);
+			}
+		} else if (msgbuf.tag.type == VIO_TYPE_CTRL) {
+			if (msgbuf.tag.stype_env == VNET_MCAST_INFO)
+				err = handle_mcast(port, &msgbuf);
+			else
+				err = vio_control_pkt_engine(vio, &msgbuf);
+			if (err)
+				break;
+		} else {
+			err = vnet_handle_unknown(port, &msgbuf);
+		}
+		if (err == -ECONNRESET)
+			break;
+	}
+	if (unlikely(tx_wakeup && err != -ECONNRESET))
+		maybe_tx_wakeup(port);
+	return npkts;
+}
+
+int sunvnet_poll_common(struct napi_struct *napi, int budget)
+{
+	struct vnet_port *port = container_of(napi, struct vnet_port, napi);
+	struct vio_driver_state *vio = &port->vio;
+	int processed = vnet_event_napi(port, budget);
+
+	if (processed < budget) {
+		napi_complete_done(napi, processed);
+		port->rx_event &= ~LDC_EVENT_DATA_READY;
+		vio_set_intr(vio->vdev->rx_ino, HV_INTR_ENABLED);
+	}
+	return processed;
+}
+EXPORT_SYMBOL_GPL(sunvnet_poll_common);
+
+void sunvnet_event_common(void *arg, int event)
+{
+	struct vnet_port *port = arg;
+	struct vio_driver_state *vio = &port->vio;
+
+	port->rx_event |= event;
+	vio_set_intr(vio->vdev->rx_ino, HV_INTR_DISABLED);
+	napi_schedule(&port->napi);
+}
+EXPORT_SYMBOL_GPL(sunvnet_event_common);
+
+static int __vnet_tx_trigger(struct vnet_port *port, u32 start)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct vio_dring_data hdr = {
+		.tag = {
+			.type		= VIO_TYPE_DATA,
+			.stype		= VIO_SUBTYPE_INFO,
+			.stype_env	= VIO_DRING_DATA,
+			.sid		= vio_send_sid(&port->vio),
+		},
+		.dring_ident		= dr->ident,
+		.start_idx		= start,
+		.end_idx		= (u32)-1,
+	};
+	int err, delay;
+	int retries = 0;
+
+	if (port->stop_rx) {
+		trace_vnet_tx_pending_stopped_ack(port->vio._local_sid,
+						  port->vio._peer_sid,
+						  port->stop_rx_idx, -1);
+		err = vnet_send_ack(port,
+				    &port->vio.drings[VIO_DRIVER_RX_RING],
+				    port->stop_rx_idx, -1,
+				    VIO_DRING_STOPPED);
+		if (err <= 0)
+			return err;
+	}
+
+	hdr.seq = dr->snd_nxt;
+	delay = 1;
+	do {
+		err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
+		if (err > 0) {
+			dr->snd_nxt++;
+			break;
+		}
+		udelay(delay);
+		if ((delay <<= 1) > 128)
+			delay = 128;
+		if (retries++ > VNET_MAX_RETRIES)
+			break;
+	} while (err == -EAGAIN);
+	trace_vnet_tx_trigger(port->vio._local_sid,
+			      port->vio._peer_sid, start, err);
+
+	return err;
+}
+
+static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port,
+					  unsigned *pending)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct sk_buff *skb = NULL;
+	int i, txi;
+
+	*pending = 0;
+
+	txi = dr->prod;
+	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {
+		struct vio_net_desc *d;
+
+		--txi;
+		if (txi < 0)
+			txi = VNET_TX_RING_SIZE - 1;
+
+		d = vio_dring_entry(dr, txi);
+
+		if (d->hdr.state == VIO_DESC_READY) {
+			(*pending)++;
+			continue;
+		}
+		if (port->tx_bufs[txi].skb) {
+			if (d->hdr.state != VIO_DESC_DONE)
+				pr_notice("invalid ring buffer state %d\n",
+					  d->hdr.state);
+			BUG_ON(port->tx_bufs[txi].skb->next);
+
+			port->tx_bufs[txi].skb->next = skb;
+			skb = port->tx_bufs[txi].skb;
+			port->tx_bufs[txi].skb = NULL;
+
+			ldc_unmap(port->vio.lp,
+				  port->tx_bufs[txi].cookies,
+				  port->tx_bufs[txi].ncookies);
+		} else if (d->hdr.state == VIO_DESC_FREE) {
+			break;
+		}
+		d->hdr.state = VIO_DESC_FREE;
+	}
+	return skb;
+}
+
+static inline void vnet_free_skbs(struct sk_buff *skb)
+{
+	struct sk_buff *next;
+
+	while (skb) {
+		next = skb->next;
+		skb->next = NULL;
+		dev_kfree_skb(skb);
+		skb = next;
+	}
+}
+
+void sunvnet_clean_timer_expire_common(struct timer_list *t)
+{
+	struct vnet_port *port = from_timer(port, t, clean_timer);
+	struct sk_buff *freeskbs;
+	unsigned pending;
+
+	netif_tx_lock(VNET_PORT_TO_NET_DEVICE(port));
+	freeskbs = vnet_clean_tx_ring(port, &pending);
+	netif_tx_unlock(VNET_PORT_TO_NET_DEVICE(port));
+
+	vnet_free_skbs(freeskbs);
+
+	if (pending)
+		(void)mod_timer(&port->clean_timer,
+				jiffies + VNET_CLEAN_TIMEOUT);
+	 else
+		del_timer(&port->clean_timer);
+}
+EXPORT_SYMBOL_GPL(sunvnet_clean_timer_expire_common);
+
+static inline int vnet_skb_map(struct ldc_channel *lp, struct sk_buff *skb,
+			       struct ldc_trans_cookie *cookies, int ncookies,
+			       unsigned int map_perm)
+{
+	int i, nc, err, blen;
+
+	/* header */
+	blen = skb_headlen(skb);
+	if (blen < ETH_ZLEN)
+		blen = ETH_ZLEN;
+	blen += VNET_PACKET_SKIP;
+	blen += 8 - (blen & 7);
+
+	err = ldc_map_single(lp, skb->data - VNET_PACKET_SKIP, blen, cookies,
+			     ncookies, map_perm);
+	if (err < 0)
+		return err;
+	nc = err;
+
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+		u8 *vaddr;
+
+		if (nc < ncookies) {
+			vaddr = kmap_atomic(skb_frag_page(f));
+			blen = skb_frag_size(f);
+			blen += 8 - (blen & 7);
+			err = ldc_map_single(lp, vaddr + skb_frag_off(f),
+					     blen, cookies + nc, ncookies - nc,
+					     map_perm);
+			kunmap_atomic(vaddr);
+		} else {
+			err = -EMSGSIZE;
+		}
+
+		if (err < 0) {
+			ldc_unmap(lp, cookies, nc);
+			return err;
+		}
+		nc += err;
+	}
+	return nc;
+}
+
+static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, int ncookies)
+{
+	struct sk_buff *nskb;
+	int i, len, pad, docopy;
+
+	len = skb->len;
+	pad = 0;
+	if (len < ETH_ZLEN) {
+		pad += ETH_ZLEN - skb->len;
+		len += pad;
+	}
+	len += VNET_PACKET_SKIP;
+	pad += 8 - (len & 7);
+
+	/* make sure we have enough cookies and alignment in every frag */
+	docopy = skb_shinfo(skb)->nr_frags >= ncookies;
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+
+		docopy |= skb_frag_off(f) & 7;
+	}
+	if (((unsigned long)skb->data & 7) != VNET_PACKET_SKIP ||
+	    skb_tailroom(skb) < pad ||
+	    skb_headroom(skb) < VNET_PACKET_SKIP || docopy) {
+		int start = 0, offset;
+		__wsum csum;
+
+		len = skb->len > ETH_ZLEN ? skb->len : ETH_ZLEN;
+		nskb = alloc_and_align_skb(skb->dev, len);
+		if (!nskb) {
+			dev_kfree_skb(skb);
+			return NULL;
+		}
+		skb_reserve(nskb, VNET_PACKET_SKIP);
+
+		nskb->protocol = skb->protocol;
+		offset = skb_mac_header(skb) - skb->data;
+		skb_set_mac_header(nskb, offset);
+		offset = skb_network_header(skb) - skb->data;
+		skb_set_network_header(nskb, offset);
+		offset = skb_transport_header(skb) - skb->data;
+		skb_set_transport_header(nskb, offset);
+
+		offset = 0;
+		nskb->csum_offset = skb->csum_offset;
+		nskb->ip_summed = skb->ip_summed;
+
+		if (skb->ip_summed == CHECKSUM_PARTIAL)
+			start = skb_checksum_start_offset(skb);
+		if (start) {
+			int offset = start + nskb->csum_offset;
+
+			/* copy the headers, no csum here */
+			if (skb_copy_bits(skb, 0, nskb->data, start)) {
+				dev_kfree_skb(nskb);
+				dev_kfree_skb(skb);
+				return NULL;
+			}
+
+			/* copy the rest, with csum calculation */
+			*(__sum16 *)(skb->data + offset) = 0;
+			csum = skb_copy_and_csum_bits(skb, start,
+						      nskb->data + start,
+						      skb->len - start);
+
+			/* add in the header checksums */
+			if (skb->protocol == htons(ETH_P_IP)) {
+				struct iphdr *iph = ip_hdr(nskb);
+
+				if (iph->protocol == IPPROTO_TCP ||
+				    iph->protocol == IPPROTO_UDP) {
+					csum = csum_tcpudp_magic(iph->saddr,
+								 iph->daddr,
+								 skb->len - start,
+								 iph->protocol,
+								 csum);
+				}
+			} else if (skb->protocol == htons(ETH_P_IPV6)) {
+				struct ipv6hdr *ip6h = ipv6_hdr(nskb);
+
+				if (ip6h->nexthdr == IPPROTO_TCP ||
+				    ip6h->nexthdr == IPPROTO_UDP) {
+					csum = csum_ipv6_magic(&ip6h->saddr,
+							       &ip6h->daddr,
+							       skb->len - start,
+							       ip6h->nexthdr,
+							       csum);
+				}
+			}
+
+			/* save the final result */
+			*(__sum16 *)(nskb->data + offset) = csum;
+
+			nskb->ip_summed = CHECKSUM_NONE;
+		} else if (skb_copy_bits(skb, 0, nskb->data, skb->len)) {
+			dev_kfree_skb(nskb);
+			dev_kfree_skb(skb);
+			return NULL;
+		}
+		(void)skb_put(nskb, skb->len);
+		if (skb_is_gso(skb)) {
+			skb_shinfo(nskb)->gso_size = skb_shinfo(skb)->gso_size;
+			skb_shinfo(nskb)->gso_type = skb_shinfo(skb)->gso_type;
+		}
+		nskb->queue_mapping = skb->queue_mapping;
+		dev_kfree_skb(skb);
+		skb = nskb;
+	}
+	return skb;
+}
+
+static netdev_tx_t
+vnet_handle_offloads(struct vnet_port *port, struct sk_buff *skb,
+		     struct vnet_port *(*vnet_tx_port)
+		     (struct sk_buff *, struct net_device *))
+{
+	struct net_device *dev = VNET_PORT_TO_NET_DEVICE(port);
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct sk_buff *segs, *curr, *next;
+	int maclen, datalen;
+	int status;
+	int gso_size, gso_type, gso_segs;
+	int hlen = skb_transport_header(skb) - skb_mac_header(skb);
+	int proto = IPPROTO_IP;
+
+	if (skb->protocol == htons(ETH_P_IP))
+		proto = ip_hdr(skb)->protocol;
+	else if (skb->protocol == htons(ETH_P_IPV6))
+		proto = ipv6_hdr(skb)->nexthdr;
+
+	if (proto == IPPROTO_TCP) {
+		hlen += tcp_hdr(skb)->doff * 4;
+	} else if (proto == IPPROTO_UDP) {
+		hlen += sizeof(struct udphdr);
+	} else {
+		pr_err("vnet_handle_offloads GSO with unknown transport "
+		       "protocol %d tproto %d\n", skb->protocol, proto);
+		hlen = 128; /* XXX */
+	}
+	datalen = port->tsolen - hlen;
+
+	gso_size = skb_shinfo(skb)->gso_size;
+	gso_type = skb_shinfo(skb)->gso_type;
+	gso_segs = skb_shinfo(skb)->gso_segs;
+
+	if (port->tso && gso_size < datalen)
+		gso_segs = DIV_ROUND_UP(skb->len - hlen, datalen);
+
+	if (unlikely(vnet_tx_dring_avail(dr) < gso_segs)) {
+		struct netdev_queue *txq;
+
+		txq  = netdev_get_tx_queue(dev, port->q_index);
+		netif_tx_stop_queue(txq);
+		if (vnet_tx_dring_avail(dr) < skb_shinfo(skb)->gso_segs)
+			return NETDEV_TX_BUSY;
+		netif_tx_wake_queue(txq);
+	}
+
+	maclen = skb_network_header(skb) - skb_mac_header(skb);
+	skb_pull(skb, maclen);
+
+	if (port->tso && gso_size < datalen) {
+		if (skb_unclone(skb, GFP_ATOMIC))
+			goto out_dropped;
+
+		/* segment to TSO size */
+		skb_shinfo(skb)->gso_size = datalen;
+		skb_shinfo(skb)->gso_segs = gso_segs;
+	}
+	segs = skb_gso_segment(skb, dev->features & ~NETIF_F_TSO);
+	if (IS_ERR(segs))
+		goto out_dropped;
+
+	skb_push(skb, maclen);
+	skb_reset_mac_header(skb);
+
+	status = 0;
+	skb_list_walk_safe(segs, curr, next) {
+		skb_mark_not_on_list(curr);
+		if (port->tso && curr->len > dev->mtu) {
+			skb_shinfo(curr)->gso_size = gso_size;
+			skb_shinfo(curr)->gso_type = gso_type;
+			skb_shinfo(curr)->gso_segs =
+				DIV_ROUND_UP(curr->len - hlen, gso_size);
+		} else {
+			skb_shinfo(curr)->gso_size = 0;
+		}
+
+		skb_push(curr, maclen);
+		skb_reset_mac_header(curr);
+		memcpy(skb_mac_header(curr), skb_mac_header(skb),
+		       maclen);
+		curr->csum_start = skb_transport_header(curr) - curr->head;
+		if (ip_hdr(curr)->protocol == IPPROTO_TCP)
+			curr->csum_offset = offsetof(struct tcphdr, check);
+		else if (ip_hdr(curr)->protocol == IPPROTO_UDP)
+			curr->csum_offset = offsetof(struct udphdr, check);
+
+		if (!(status & NETDEV_TX_MASK))
+			status = sunvnet_start_xmit_common(curr, dev,
+							   vnet_tx_port);
+		if (status & NETDEV_TX_MASK)
+			dev_kfree_skb_any(curr);
+	}
+
+	if (!(status & NETDEV_TX_MASK))
+		dev_kfree_skb_any(skb);
+	return status;
+out_dropped:
+	dev->stats.tx_dropped++;
+	dev_kfree_skb_any(skb);
+	return NETDEV_TX_OK;
+}
+
+netdev_tx_t
+sunvnet_start_xmit_common(struct sk_buff *skb, struct net_device *dev,
+			  struct vnet_port *(*vnet_tx_port)
+			  (struct sk_buff *, struct net_device *))
+{
+	struct vnet_port *port = NULL;
+	struct vio_dring_state *dr;
+	struct vio_net_desc *d;
+	unsigned int len;
+	struct sk_buff *freeskbs = NULL;
+	int i, err, txi;
+	unsigned pending = 0;
+	struct netdev_queue *txq;
+
+	rcu_read_lock();
+	port = vnet_tx_port(skb, dev);
+	if (unlikely(!port))
+		goto out_dropped;
+
+	if (skb_is_gso(skb) && skb->len > port->tsolen) {
+		err = vnet_handle_offloads(port, skb, vnet_tx_port);
+		rcu_read_unlock();
+		return err;
+	}
+
+	if (!skb_is_gso(skb) && skb->len > port->rmtu) {
+		unsigned long localmtu = port->rmtu - ETH_HLEN;
+
+		if (vio_version_after_eq(&port->vio, 1, 3))
+			localmtu -= VLAN_HLEN;
+
+		if (skb->protocol == htons(ETH_P_IP))
+			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+				      htonl(localmtu));
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, localmtu);
+#endif
+		goto out_dropped;
+	}
+
+	skb = vnet_skb_shape(skb, 2);
+
+	if (unlikely(!skb))
+		goto out_dropped;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		if (skb->protocol == htons(ETH_P_IP))
+			vnet_fullcsum_ipv4(skb);
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			vnet_fullcsum_ipv6(skb);
+#endif
+	}
+
+	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	i = skb_get_queue_mapping(skb);
+	txq = netdev_get_tx_queue(dev, i);
+	if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
+		if (!netif_tx_queue_stopped(txq)) {
+			netif_tx_stop_queue(txq);
+
+			/* This is a hard error, log it. */
+			netdev_err(dev, "BUG! Tx Ring full when queue awake!\n");
+			dev->stats.tx_errors++;
+		}
+		rcu_read_unlock();
+		return NETDEV_TX_BUSY;
+	}
+
+	d = vio_dring_cur(dr);
+
+	txi = dr->prod;
+
+	freeskbs = vnet_clean_tx_ring(port, &pending);
+
+	BUG_ON(port->tx_bufs[txi].skb);
+
+	len = skb->len;
+	if (len < ETH_ZLEN)
+		len = ETH_ZLEN;
+
+	err = vnet_skb_map(port->vio.lp, skb, port->tx_bufs[txi].cookies, 2,
+			   (LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_RW));
+	if (err < 0) {
+		netdev_info(dev, "tx buffer map error %d\n", err);
+		goto out_dropped;
+	}
+
+	port->tx_bufs[txi].skb = skb;
+	skb = NULL;
+	port->tx_bufs[txi].ncookies = err;
+
+	/* We don't rely on the ACKs to free the skb in vnet_start_xmit(),
+	 * thus it is safe to not set VIO_ACK_ENABLE for each transmission:
+	 * the protocol itself does not require it as long as the peer
+	 * sends a VIO_SUBTYPE_ACK for VIO_DRING_STOPPED.
+	 *
+	 * An ACK for every packet in the ring is expensive as the
+	 * sending of LDC messages is slow and affects performance.
+	 */
+	d->hdr.ack = VIO_ACK_DISABLE;
+	d->size = len;
+	d->ncookies = port->tx_bufs[txi].ncookies;
+	for (i = 0; i < d->ncookies; i++)
+		d->cookies[i] = port->tx_bufs[txi].cookies[i];
+	if (vio_version_after_eq(&port->vio, 1, 7)) {
+		struct vio_net_dext *dext = vio_net_ext(d);
+
+		memset(dext, 0, sizeof(*dext));
+		if (skb_is_gso(port->tx_bufs[txi].skb)) {
+			dext->ipv4_lso_mss = skb_shinfo(port->tx_bufs[txi].skb)
+					     ->gso_size;
+			dext->flags |= VNET_PKT_IPV4_LSO;
+		}
+		if (vio_version_after_eq(&port->vio, 1, 8) &&
+		    !port->switch_port) {
+			dext->flags |= VNET_PKT_HCK_IPV4_HDRCKSUM_OK;
+			dext->flags |= VNET_PKT_HCK_FULLCKSUM_OK;
+		}
+	}
+
+	/* This has to be a non-SMP write barrier because we are writing
+	 * to memory which is shared with the peer LDOM.
+	 */
+	dma_wmb();
+
+	d->hdr.state = VIO_DESC_READY;
+
+	/* Exactly one ldc "start" trigger (for dr->cons) needs to be sent
+	 * to notify the consumer that some descriptors are READY.
+	 * After that "start" trigger, no additional triggers are needed until
+	 * a DRING_STOPPED is received from the consumer. The dr->cons field
+	 * (set up by vnet_ack()) has the value of the next dring index
+	 * that has not yet been ack-ed. We send a "start" trigger here
+	 * if, and only if, start_cons is true (reset it afterward). Conversely,
+	 * vnet_ack() should check if the dring corresponding to cons
+	 * is marked READY, but start_cons was false.
+	 * If so, vnet_ack() should send out the missed "start" trigger.
+	 *
+	 * Note that the dma_wmb() above makes sure the cookies et al. are
+	 * not globally visible before the VIO_DESC_READY, and that the
+	 * stores are ordered correctly by the compiler. The consumer will
+	 * not proceed until the VIO_DESC_READY is visible assuring that
+	 * the consumer does not observe anything related to descriptors
+	 * out of order. The HV trap from the LDC start trigger is the
+	 * producer to consumer announcement that work is available to the
+	 * consumer
+	 */
+	if (!port->start_cons) { /* previous trigger suffices */
+		trace_vnet_skip_tx_trigger(port->vio._local_sid,
+					   port->vio._peer_sid, dr->cons);
+		goto ldc_start_done;
+	}
+
+	err = __vnet_tx_trigger(port, dr->cons);
+	if (unlikely(err < 0)) {
+		netdev_info(dev, "TX trigger error %d\n", err);
+		d->hdr.state = VIO_DESC_FREE;
+		skb = port->tx_bufs[txi].skb;
+		port->tx_bufs[txi].skb = NULL;
+		dev->stats.tx_carrier_errors++;
+		goto out_dropped;
+	}
+
+ldc_start_done:
+	port->start_cons = false;
+
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += port->tx_bufs[txi].skb->len;
+	port->stats.tx_packets++;
+	port->stats.tx_bytes += port->tx_bufs[txi].skb->len;
+
+	dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
+	if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
+		netif_tx_stop_queue(txq);
+		smp_rmb();
+		if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
+			netif_tx_wake_queue(txq);
+	}
+
+	(void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);
+	rcu_read_unlock();
+
+	vnet_free_skbs(freeskbs);
+
+	return NETDEV_TX_OK;
+
+out_dropped:
+	if (pending)
+		(void)mod_timer(&port->clean_timer,
+				jiffies + VNET_CLEAN_TIMEOUT);
+	else if (port)
+		del_timer(&port->clean_timer);
+	rcu_read_unlock();
+	dev_kfree_skb(skb);
+	vnet_free_skbs(freeskbs);
+	dev->stats.tx_dropped++;
+	return NETDEV_TX_OK;
+}
+EXPORT_SYMBOL_GPL(sunvnet_start_xmit_common);
+
+void sunvnet_tx_timeout_common(struct net_device *dev, unsigned int txqueue)
+{
+	/* XXX Implement me XXX */
+}
+EXPORT_SYMBOL_GPL(sunvnet_tx_timeout_common);
+
+int sunvnet_open_common(struct net_device *dev)
+{
+	netif_carrier_on(dev);
+	netif_tx_start_all_queues(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sunvnet_open_common);
+
+int sunvnet_close_common(struct net_device *dev)
+{
+	netif_tx_stop_all_queues(dev);
+	netif_carrier_off(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sunvnet_close_common);
+
+static struct vnet_mcast_entry *__vnet_mc_find(struct vnet *vp, u8 *addr)
+{
+	struct vnet_mcast_entry *m;
+
+	for (m = vp->mcast_list; m; m = m->next) {
+		if (ether_addr_equal(m->addr, addr))
+			return m;
+	}
+	return NULL;
+}
+
+static void __update_mc_list(struct vnet *vp, struct net_device *dev)
+{
+	struct netdev_hw_addr *ha;
+
+	netdev_for_each_mc_addr(ha, dev) {
+		struct vnet_mcast_entry *m;
+
+		m = __vnet_mc_find(vp, ha->addr);
+		if (m) {
+			m->hit = 1;
+			continue;
+		}
+
+		if (!m) {
+			m = kzalloc(sizeof(*m), GFP_ATOMIC);
+			if (!m)
+				continue;
+			memcpy(m->addr, ha->addr, ETH_ALEN);
+			m->hit = 1;
+
+			m->next = vp->mcast_list;
+			vp->mcast_list = m;
+		}
+	}
+}
+
+static void __send_mc_list(struct vnet *vp, struct vnet_port *port)
+{
+	struct vio_net_mcast_info info;
+	struct vnet_mcast_entry *m, **pp;
+	int n_addrs;
+
+	memset(&info, 0, sizeof(info));
+
+	info.tag.type = VIO_TYPE_CTRL;
+	info.tag.stype = VIO_SUBTYPE_INFO;
+	info.tag.stype_env = VNET_MCAST_INFO;
+	info.tag.sid = vio_send_sid(&port->vio);
+	info.set = 1;
+
+	n_addrs = 0;
+	for (m = vp->mcast_list; m; m = m->next) {
+		if (m->sent)
+			continue;
+		m->sent = 1;
+		memcpy(&info.mcast_addr[n_addrs * ETH_ALEN],
+		       m->addr, ETH_ALEN);
+		if (++n_addrs == VNET_NUM_MCAST) {
+			info.count = n_addrs;
+
+			(void)vio_ldc_send(&port->vio, &info,
+					   sizeof(info));
+			n_addrs = 0;
+		}
+	}
+	if (n_addrs) {
+		info.count = n_addrs;
+		(void)vio_ldc_send(&port->vio, &info, sizeof(info));
+	}
+
+	info.set = 0;
+
+	n_addrs = 0;
+	pp = &vp->mcast_list;
+	while ((m = *pp) != NULL) {
+		if (m->hit) {
+			m->hit = 0;
+			pp = &m->next;
+			continue;
+		}
+
+		memcpy(&info.mcast_addr[n_addrs * ETH_ALEN],
+		       m->addr, ETH_ALEN);
+		if (++n_addrs == VNET_NUM_MCAST) {
+			info.count = n_addrs;
+			(void)vio_ldc_send(&port->vio, &info,
+					   sizeof(info));
+			n_addrs = 0;
+		}
+
+		*pp = m->next;
+		kfree(m);
+	}
+	if (n_addrs) {
+		info.count = n_addrs;
+		(void)vio_ldc_send(&port->vio, &info, sizeof(info));
+	}
+}
+
+void sunvnet_set_rx_mode_common(struct net_device *dev, struct vnet *vp)
+{
+	struct vnet_port *port;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(port, &vp->port_list, list) {
+		if (port->switch_port) {
+			__update_mc_list(vp, dev);
+			__send_mc_list(vp, port);
+			break;
+		}
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(sunvnet_set_rx_mode_common);
+
+int sunvnet_set_mac_addr_common(struct net_device *dev, void *p)
+{
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(sunvnet_set_mac_addr_common);
+
+void sunvnet_port_free_tx_bufs_common(struct vnet_port *port)
+{
+	struct vio_dring_state *dr;
+	int i;
+
+	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+
+	if (!dr->base)
+		return;
+
+	for (i = 0; i < VNET_TX_RING_SIZE; i++) {
+		struct vio_net_desc *d;
+		void *skb = port->tx_bufs[i].skb;
+
+		if (!skb)
+			continue;
+
+		d = vio_dring_entry(dr, i);
+
+		ldc_unmap(port->vio.lp,
+			  port->tx_bufs[i].cookies,
+			  port->tx_bufs[i].ncookies);
+		dev_kfree_skb(skb);
+		port->tx_bufs[i].skb = NULL;
+		d->hdr.state = VIO_DESC_FREE;
+	}
+	ldc_free_exp_dring(port->vio.lp, dr->base,
+			   (dr->entry_size * dr->num_entries),
+			   dr->cookies, dr->ncookies);
+	dr->base = NULL;
+	dr->entry_size = 0;
+	dr->num_entries = 0;
+	dr->pending = 0;
+	dr->ncookies = 0;
+}
+EXPORT_SYMBOL_GPL(sunvnet_port_free_tx_bufs_common);
+
+void vnet_port_reset(struct vnet_port *port)
+{
+	del_timer(&port->clean_timer);
+	sunvnet_port_free_tx_bufs_common(port);
+	port->rmtu = 0;
+	port->tso = (port->vsw == 0);  /* no tso in vsw, misbehaves in bridge */
+	port->tsolen = 0;
+}
+EXPORT_SYMBOL_GPL(vnet_port_reset);
+
+static int vnet_port_alloc_tx_ring(struct vnet_port *port)
+{
+	struct vio_dring_state *dr;
+	unsigned long len, elen;
+	int i, err, ncookies;
+	void *dring;
+
+	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+
+	elen = sizeof(struct vio_net_desc) +
+	       sizeof(struct ldc_trans_cookie) * 2;
+	if (vio_version_after_eq(&port->vio, 1, 7))
+		elen += sizeof(struct vio_net_dext);
+	len = VNET_TX_RING_SIZE * elen;
+
+	ncookies = VIO_MAX_RING_COOKIES;
+	dring = ldc_alloc_exp_dring(port->vio.lp, len,
+				    dr->cookies, &ncookies,
+				    (LDC_MAP_SHADOW |
+				     LDC_MAP_DIRECT |
+				     LDC_MAP_RW));
+	if (IS_ERR(dring)) {
+		err = PTR_ERR(dring);
+		goto err_out;
+	}
+
+	dr->base = dring;
+	dr->entry_size = elen;
+	dr->num_entries = VNET_TX_RING_SIZE;
+	dr->prod = 0;
+	dr->cons = 0;
+	port->start_cons  = true; /* need an initial trigger */
+	dr->pending = VNET_TX_RING_SIZE;
+	dr->ncookies = ncookies;
+
+	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {
+		struct vio_net_desc *d;
+
+		d = vio_dring_entry(dr, i);
+		d->hdr.state = VIO_DESC_FREE;
+	}
+	return 0;
+
+err_out:
+	sunvnet_port_free_tx_bufs_common(port);
+
+	return err;
+}
+
+#ifdef CONFIG_NET_POLL_CONTROLLER
+void sunvnet_poll_controller_common(struct net_device *dev, struct vnet *vp)
+{
+	struct vnet_port *port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&vp->lock, flags);
+	if (!list_empty(&vp->port_list)) {
+		port = list_entry(vp->port_list.next, struct vnet_port, list);
+		napi_schedule(&port->napi);
+	}
+	spin_unlock_irqrestore(&vp->lock, flags);
+}
+EXPORT_SYMBOL_GPL(sunvnet_poll_controller_common);
+#endif
+
+void sunvnet_port_add_txq_common(struct vnet_port *port)
+{
+	struct vnet *vp = port->vp;
+	int smallest = 0;
+	int i;
+
+	/* find the first least-used q
+	 * When there are more ldoms than q's, we start to
+	 * double up on ports per queue.
+	 */
+	for (i = 0; i < VNET_MAX_TXQS; i++) {
+		if (vp->q_used[i] == 0) {
+			smallest = i;
+			break;
+		}
+		if (vp->q_used[i] < vp->q_used[smallest])
+			smallest = i;
+	}
+
+	vp->nports++;
+	vp->q_used[smallest]++;
+	port->q_index = smallest;
+}
+EXPORT_SYMBOL_GPL(sunvnet_port_add_txq_common);
+
+void sunvnet_port_rm_txq_common(struct vnet_port *port)
+{
+	port->vp->nports--;
+	port->vp->q_used[port->q_index]--;
+	port->q_index = 0;
+}
+EXPORT_SYMBOL_GPL(sunvnet_port_rm_txq_common);