Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 1274 insertions, 0 deletions

diff --git a/drivers/net/ethernet/google/gve/gve_tx_dqo.c b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
new file mode 100644
index 0000000000..1e19b834a6
--- /dev/null
+++ b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
@@ -0,0 +1,1274 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+#include "gve.h"
+#include "gve_adminq.h"
+#include "gve_utils.h"
+#include "gve_dqo.h"
+#include <net/ip.h>
+#include <linux/tcp.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+
+/* Returns true if tx_bufs are available. */
+static bool gve_has_free_tx_qpl_bufs(struct gve_tx_ring *tx, int count)
+{
+	int num_avail;
+
+	if (!tx->dqo.qpl)
+		return true;
+
+	num_avail = tx->dqo.num_tx_qpl_bufs -
+		(tx->dqo_tx.alloc_tx_qpl_buf_cnt -
+		 tx->dqo_tx.free_tx_qpl_buf_cnt);
+
+	if (count <= num_avail)
+		return true;
+
+	/* Update cached value from dqo_compl. */
+	tx->dqo_tx.free_tx_qpl_buf_cnt =
+		atomic_read_acquire(&tx->dqo_compl.free_tx_qpl_buf_cnt);
+
+	num_avail = tx->dqo.num_tx_qpl_bufs -
+		(tx->dqo_tx.alloc_tx_qpl_buf_cnt -
+		 tx->dqo_tx.free_tx_qpl_buf_cnt);
+
+	return count <= num_avail;
+}
+
+static s16
+gve_alloc_tx_qpl_buf(struct gve_tx_ring *tx)
+{
+	s16 index;
+
+	index = tx->dqo_tx.free_tx_qpl_buf_head;
+
+	/* No TX buffers available, try to steal the list from the
+	 * completion handler.
+	 */
+	if (unlikely(index == -1)) {
+		tx->dqo_tx.free_tx_qpl_buf_head =
+			atomic_xchg(&tx->dqo_compl.free_tx_qpl_buf_head, -1);
+		index = tx->dqo_tx.free_tx_qpl_buf_head;
+
+		if (unlikely(index == -1))
+			return index;
+	}
+
+	/* Remove TX buf from free list */
+	tx->dqo_tx.free_tx_qpl_buf_head = tx->dqo.tx_qpl_buf_next[index];
+
+	return index;
+}
+
+static void
+gve_free_tx_qpl_bufs(struct gve_tx_ring *tx,
+		     struct gve_tx_pending_packet_dqo *pkt)
+{
+	s16 index;
+	int i;
+
+	if (!pkt->num_bufs)
+		return;
+
+	index = pkt->tx_qpl_buf_ids[0];
+	/* Create a linked list of buffers to be added to the free list */
+	for (i = 1; i < pkt->num_bufs; i++) {
+		tx->dqo.tx_qpl_buf_next[index] = pkt->tx_qpl_buf_ids[i];
+		index = pkt->tx_qpl_buf_ids[i];
+	}
+
+	while (true) {
+		s16 old_head = atomic_read_acquire(&tx->dqo_compl.free_tx_qpl_buf_head);
+
+		tx->dqo.tx_qpl_buf_next[index] = old_head;
+		if (atomic_cmpxchg(&tx->dqo_compl.free_tx_qpl_buf_head,
+				   old_head,
+				   pkt->tx_qpl_buf_ids[0]) == old_head) {
+			break;
+		}
+	}
+
+	atomic_add(pkt->num_bufs, &tx->dqo_compl.free_tx_qpl_buf_cnt);
+	pkt->num_bufs = 0;
+}
+
+/* Returns true if a gve_tx_pending_packet_dqo object is available. */
+static bool gve_has_pending_packet(struct gve_tx_ring *tx)
+{
+	/* Check TX path's list. */
+	if (tx->dqo_tx.free_pending_packets != -1)
+		return true;
+
+	/* Check completion handler's list. */
+	if (atomic_read_acquire(&tx->dqo_compl.free_pending_packets) != -1)
+		return true;
+
+	return false;
+}
+
+static struct gve_tx_pending_packet_dqo *
+gve_alloc_pending_packet(struct gve_tx_ring *tx)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	s16 index;
+
+	index = tx->dqo_tx.free_pending_packets;
+
+	/* No pending_packets available, try to steal the list from the
+	 * completion handler.
+	 */
+	if (unlikely(index == -1)) {
+		tx->dqo_tx.free_pending_packets =
+			atomic_xchg(&tx->dqo_compl.free_pending_packets, -1);
+		index = tx->dqo_tx.free_pending_packets;
+
+		if (unlikely(index == -1))
+			return NULL;
+	}
+
+	pending_packet = &tx->dqo.pending_packets[index];
+
+	/* Remove pending_packet from free list */
+	tx->dqo_tx.free_pending_packets = pending_packet->next;
+	pending_packet->state = GVE_PACKET_STATE_PENDING_DATA_COMPL;
+
+	return pending_packet;
+}
+
+static void
+gve_free_pending_packet(struct gve_tx_ring *tx,
+			struct gve_tx_pending_packet_dqo *pending_packet)
+{
+	s16 index = pending_packet - tx->dqo.pending_packets;
+
+	pending_packet->state = GVE_PACKET_STATE_UNALLOCATED;
+	while (true) {
+		s16 old_head = atomic_read_acquire(&tx->dqo_compl.free_pending_packets);
+
+		pending_packet->next = old_head;
+		if (atomic_cmpxchg(&tx->dqo_compl.free_pending_packets,
+				   old_head, index) == old_head) {
+			break;
+		}
+	}
+}
+
+/* gve_tx_free_desc - Cleans up all pending tx requests and buffers.
+ */
+static void gve_tx_clean_pending_packets(struct gve_tx_ring *tx)
+{
+	int i;
+
+	for (i = 0; i < tx->dqo.num_pending_packets; i++) {
+		struct gve_tx_pending_packet_dqo *cur_state =
+			&tx->dqo.pending_packets[i];
+		int j;
+
+		for (j = 0; j < cur_state->num_bufs; j++) {
+			if (j == 0) {
+				dma_unmap_single(tx->dev,
+					dma_unmap_addr(cur_state, dma[j]),
+					dma_unmap_len(cur_state, len[j]),
+					DMA_TO_DEVICE);
+			} else {
+				dma_unmap_page(tx->dev,
+					dma_unmap_addr(cur_state, dma[j]),
+					dma_unmap_len(cur_state, len[j]),
+					DMA_TO_DEVICE);
+			}
+		}
+		if (cur_state->skb) {
+			dev_consume_skb_any(cur_state->skb);
+			cur_state->skb = NULL;
+		}
+	}
+}
+
+static void gve_tx_free_ring_dqo(struct gve_priv *priv, int idx)
+{
+	struct gve_tx_ring *tx = &priv->tx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	size_t bytes;
+
+	gve_tx_remove_from_block(priv, idx);
+
+	if (tx->q_resources) {
+		dma_free_coherent(hdev, sizeof(*tx->q_resources),
+				  tx->q_resources, tx->q_resources_bus);
+		tx->q_resources = NULL;
+	}
+
+	if (tx->dqo.compl_ring) {
+		bytes = sizeof(tx->dqo.compl_ring[0]) *
+			(tx->dqo.complq_mask + 1);
+		dma_free_coherent(hdev, bytes, tx->dqo.compl_ring,
+				  tx->complq_bus_dqo);
+		tx->dqo.compl_ring = NULL;
+	}
+
+	if (tx->dqo.tx_ring) {
+		bytes = sizeof(tx->dqo.tx_ring[0]) * (tx->mask + 1);
+		dma_free_coherent(hdev, bytes, tx->dqo.tx_ring, tx->bus);
+		tx->dqo.tx_ring = NULL;
+	}
+
+	kvfree(tx->dqo.pending_packets);
+	tx->dqo.pending_packets = NULL;
+
+	kvfree(tx->dqo.tx_qpl_buf_next);
+	tx->dqo.tx_qpl_buf_next = NULL;
+
+	if (tx->dqo.qpl) {
+		gve_unassign_qpl(priv, tx->dqo.qpl->id);
+		tx->dqo.qpl = NULL;
+	}
+
+	netif_dbg(priv, drv, priv->dev, "freed tx queue %d\n", idx);
+}
+
+static int gve_tx_qpl_buf_init(struct gve_tx_ring *tx)
+{
+	int num_tx_qpl_bufs = GVE_TX_BUFS_PER_PAGE_DQO *
+		tx->dqo.qpl->num_entries;
+	int i;
+
+	tx->dqo.tx_qpl_buf_next = kvcalloc(num_tx_qpl_bufs,
+					   sizeof(tx->dqo.tx_qpl_buf_next[0]),
+					   GFP_KERNEL);
+	if (!tx->dqo.tx_qpl_buf_next)
+		return -ENOMEM;
+
+	tx->dqo.num_tx_qpl_bufs = num_tx_qpl_bufs;
+
+	/* Generate free TX buf list */
+	for (i = 0; i < num_tx_qpl_bufs - 1; i++)
+		tx->dqo.tx_qpl_buf_next[i] = i + 1;
+	tx->dqo.tx_qpl_buf_next[num_tx_qpl_bufs - 1] = -1;
+
+	atomic_set_release(&tx->dqo_compl.free_tx_qpl_buf_head, -1);
+	return 0;
+}
+
+static int gve_tx_alloc_ring_dqo(struct gve_priv *priv, int idx)
+{
+	struct gve_tx_ring *tx = &priv->tx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	int num_pending_packets;
+	size_t bytes;
+	int i;
+
+	memset(tx, 0, sizeof(*tx));
+	tx->q_num = idx;
+	tx->dev = &priv->pdev->dev;
+	tx->netdev_txq = netdev_get_tx_queue(priv->dev, idx);
+	atomic_set_release(&tx->dqo_compl.hw_tx_head, 0);
+
+	/* Queue sizes must be a power of 2 */
+	tx->mask = priv->tx_desc_cnt - 1;
+	tx->dqo.complq_mask = priv->queue_format == GVE_DQO_RDA_FORMAT ?
+		priv->options_dqo_rda.tx_comp_ring_entries - 1 :
+		tx->mask;
+
+	/* The max number of pending packets determines the maximum number of
+	 * descriptors which maybe written to the completion queue.
+	 *
+	 * We must set the number small enough to make sure we never overrun the
+	 * completion queue.
+	 */
+	num_pending_packets = tx->dqo.complq_mask + 1;
+
+	/* Reserve space for descriptor completions, which will be reported at
+	 * most every GVE_TX_MIN_RE_INTERVAL packets.
+	 */
+	num_pending_packets -=
+		(tx->dqo.complq_mask + 1) / GVE_TX_MIN_RE_INTERVAL;
+
+	/* Each packet may have at most 2 buffer completions if it receives both
+	 * a miss and reinjection completion.
+	 */
+	num_pending_packets /= 2;
+
+	tx->dqo.num_pending_packets = min_t(int, num_pending_packets, S16_MAX);
+	tx->dqo.pending_packets = kvcalloc(tx->dqo.num_pending_packets,
+					   sizeof(tx->dqo.pending_packets[0]),
+					   GFP_KERNEL);
+	if (!tx->dqo.pending_packets)
+		goto err;
+
+	/* Set up linked list of pending packets */
+	for (i = 0; i < tx->dqo.num_pending_packets - 1; i++)
+		tx->dqo.pending_packets[i].next = i + 1;
+
+	tx->dqo.pending_packets[tx->dqo.num_pending_packets - 1].next = -1;
+	atomic_set_release(&tx->dqo_compl.free_pending_packets, -1);
+	tx->dqo_compl.miss_completions.head = -1;
+	tx->dqo_compl.miss_completions.tail = -1;
+	tx->dqo_compl.timed_out_completions.head = -1;
+	tx->dqo_compl.timed_out_completions.tail = -1;
+
+	bytes = sizeof(tx->dqo.tx_ring[0]) * (tx->mask + 1);
+	tx->dqo.tx_ring = dma_alloc_coherent(hdev, bytes, &tx->bus, GFP_KERNEL);
+	if (!tx->dqo.tx_ring)
+		goto err;
+
+	bytes = sizeof(tx->dqo.compl_ring[0]) * (tx->dqo.complq_mask + 1);
+	tx->dqo.compl_ring = dma_alloc_coherent(hdev, bytes,
+						&tx->complq_bus_dqo,
+						GFP_KERNEL);
+	if (!tx->dqo.compl_ring)
+		goto err;
+
+	tx->q_resources = dma_alloc_coherent(hdev, sizeof(*tx->q_resources),
+					     &tx->q_resources_bus, GFP_KERNEL);
+	if (!tx->q_resources)
+		goto err;
+
+	if (gve_is_qpl(priv)) {
+		tx->dqo.qpl = gve_assign_tx_qpl(priv, idx);
+		if (!tx->dqo.qpl)
+			goto err;
+
+		if (gve_tx_qpl_buf_init(tx))
+			goto err;
+	}
+
+	gve_tx_add_to_block(priv, idx);
+
+	return 0;
+
+err:
+	gve_tx_free_ring_dqo(priv, idx);
+	return -ENOMEM;
+}
+
+int gve_tx_alloc_rings_dqo(struct gve_priv *priv)
+{
+	int err = 0;
+	int i;
+
+	for (i = 0; i < priv->tx_cfg.num_queues; i++) {
+		err = gve_tx_alloc_ring_dqo(priv, i);
+		if (err) {
+			netif_err(priv, drv, priv->dev,
+				  "Failed to alloc tx ring=%d: err=%d\n",
+				  i, err);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	for (i--; i >= 0; i--)
+		gve_tx_free_ring_dqo(priv, i);
+
+	return err;
+}
+
+void gve_tx_free_rings_dqo(struct gve_priv *priv)
+{
+	int i;
+
+	for (i = 0; i < priv->tx_cfg.num_queues; i++) {
+		struct gve_tx_ring *tx = &priv->tx[i];
+
+		gve_clean_tx_done_dqo(priv, tx, /*napi=*/NULL);
+		netdev_tx_reset_queue(tx->netdev_txq);
+		gve_tx_clean_pending_packets(tx);
+
+		gve_tx_free_ring_dqo(priv, i);
+	}
+}
+
+/* Returns the number of slots available in the ring */
+static u32 num_avail_tx_slots(const struct gve_tx_ring *tx)
+{
+	u32 num_used = (tx->dqo_tx.tail - tx->dqo_tx.head) & tx->mask;
+
+	return tx->mask - num_used;
+}
+
+static bool gve_has_avail_slots_tx_dqo(struct gve_tx_ring *tx,
+				       int desc_count, int buf_count)
+{
+	return gve_has_pending_packet(tx) &&
+		   num_avail_tx_slots(tx) >= desc_count &&
+		   gve_has_free_tx_qpl_bufs(tx, buf_count);
+}
+
+/* Stops the queue if available descriptors is less than 'count'.
+ * Return: 0 if stop is not required.
+ */
+static int gve_maybe_stop_tx_dqo(struct gve_tx_ring *tx,
+				 int desc_count, int buf_count)
+{
+	if (likely(gve_has_avail_slots_tx_dqo(tx, desc_count, buf_count)))
+		return 0;
+
+	/* Update cached TX head pointer */
+	tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
+
+	if (likely(gve_has_avail_slots_tx_dqo(tx, desc_count, buf_count)))
+		return 0;
+
+	/* No space, so stop the queue */
+	tx->stop_queue++;
+	netif_tx_stop_queue(tx->netdev_txq);
+
+	/* Sync with restarting queue in `gve_tx_poll_dqo()` */
+	mb();
+
+	/* After stopping queue, check if we can transmit again in order to
+	 * avoid TOCTOU bug.
+	 */
+	tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
+
+	if (likely(!gve_has_avail_slots_tx_dqo(tx, desc_count, buf_count)))
+		return -EBUSY;
+
+	netif_tx_start_queue(tx->netdev_txq);
+	tx->wake_queue++;
+	return 0;
+}
+
+static void gve_extract_tx_metadata_dqo(const struct sk_buff *skb,
+					struct gve_tx_metadata_dqo *metadata)
+{
+	memset(metadata, 0, sizeof(*metadata));
+	metadata->version = GVE_TX_METADATA_VERSION_DQO;
+
+	if (skb->l4_hash) {
+		u16 path_hash = skb->hash ^ (skb->hash >> 16);
+
+		path_hash &= (1 << 15) - 1;
+		if (unlikely(path_hash == 0))
+			path_hash = ~path_hash;
+
+		metadata->path_hash = path_hash;
+	}
+}
+
+static void gve_tx_fill_pkt_desc_dqo(struct gve_tx_ring *tx, u32 *desc_idx,
+				     struct sk_buff *skb, u32 len, u64 addr,
+				     s16 compl_tag, bool eop, bool is_gso)
+{
+	const bool checksum_offload_en = skb->ip_summed == CHECKSUM_PARTIAL;
+
+	while (len > 0) {
+		struct gve_tx_pkt_desc_dqo *desc =
+			&tx->dqo.tx_ring[*desc_idx].pkt;
+		u32 cur_len = min_t(u32, len, GVE_TX_MAX_BUF_SIZE_DQO);
+		bool cur_eop = eop && cur_len == len;
+
+		*desc = (struct gve_tx_pkt_desc_dqo){
+			.buf_addr = cpu_to_le64(addr),
+			.dtype = GVE_TX_PKT_DESC_DTYPE_DQO,
+			.end_of_packet = cur_eop,
+			.checksum_offload_enable = checksum_offload_en,
+			.compl_tag = cpu_to_le16(compl_tag),
+			.buf_size = cur_len,
+		};
+
+		addr += cur_len;
+		len -= cur_len;
+		*desc_idx = (*desc_idx + 1) & tx->mask;
+	}
+}
+
+/* Validates and prepares `skb` for TSO.
+ *
+ * Returns header length, or < 0 if invalid.
+ */
+static int gve_prep_tso(struct sk_buff *skb)
+{
+	struct tcphdr *tcp;
+	int header_len;
+	u32 paylen;
+	int err;
+
+	/* Note: HW requires MSS (gso_size) to be <= 9728 and the total length
+	 * of the TSO to be <= 262143.
+	 *
+	 * However, we don't validate these because:
+	 * - Hypervisor enforces a limit of 9K MTU
+	 * - Kernel will not produce a TSO larger than 64k
+	 */
+
+	if (unlikely(skb_shinfo(skb)->gso_size < GVE_TX_MIN_TSO_MSS_DQO))
+		return -1;
+
+	/* Needed because we will modify header. */
+	err = skb_cow_head(skb, 0);
+	if (err < 0)
+		return err;
+
+	tcp = tcp_hdr(skb);
+
+	/* Remove payload length from checksum. */
+	paylen = skb->len - skb_transport_offset(skb);
+
+	switch (skb_shinfo(skb)->gso_type) {
+	case SKB_GSO_TCPV4:
+	case SKB_GSO_TCPV6:
+		csum_replace_by_diff(&tcp->check,
+				     (__force __wsum)htonl(paylen));
+
+		/* Compute length of segmentation header. */
+		header_len = skb_tcp_all_headers(skb);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (unlikely(header_len > GVE_TX_MAX_HDR_SIZE_DQO))
+		return -EINVAL;
+
+	return header_len;
+}
+
+static void gve_tx_fill_tso_ctx_desc(struct gve_tx_tso_context_desc_dqo *desc,
+				     const struct sk_buff *skb,
+				     const struct gve_tx_metadata_dqo *metadata,
+				     int header_len)
+{
+	*desc = (struct gve_tx_tso_context_desc_dqo){
+		.header_len = header_len,
+		.cmd_dtype = {
+			.dtype = GVE_TX_TSO_CTX_DESC_DTYPE_DQO,
+			.tso = 1,
+		},
+		.flex0 = metadata->bytes[0],
+		.flex5 = metadata->bytes[5],
+		.flex6 = metadata->bytes[6],
+		.flex7 = metadata->bytes[7],
+		.flex8 = metadata->bytes[8],
+		.flex9 = metadata->bytes[9],
+		.flex10 = metadata->bytes[10],
+		.flex11 = metadata->bytes[11],
+	};
+	desc->tso_total_len = skb->len - header_len;
+	desc->mss = skb_shinfo(skb)->gso_size;
+}
+
+static void
+gve_tx_fill_general_ctx_desc(struct gve_tx_general_context_desc_dqo *desc,
+			     const struct gve_tx_metadata_dqo *metadata)
+{
+	*desc = (struct gve_tx_general_context_desc_dqo){
+		.flex0 = metadata->bytes[0],
+		.flex1 = metadata->bytes[1],
+		.flex2 = metadata->bytes[2],
+		.flex3 = metadata->bytes[3],
+		.flex4 = metadata->bytes[4],
+		.flex5 = metadata->bytes[5],
+		.flex6 = metadata->bytes[6],
+		.flex7 = metadata->bytes[7],
+		.flex8 = metadata->bytes[8],
+		.flex9 = metadata->bytes[9],
+		.flex10 = metadata->bytes[10],
+		.flex11 = metadata->bytes[11],
+		.cmd_dtype = {.dtype = GVE_TX_GENERAL_CTX_DESC_DTYPE_DQO},
+	};
+}
+
+static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
+				      struct sk_buff *skb,
+				      struct gve_tx_pending_packet_dqo *pkt,
+				      s16 completion_tag,
+				      u32 *desc_idx,
+				      bool is_gso)
+{
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	int i;
+
+	/* Note: HW requires that the size of a non-TSO packet be within the
+	 * range of [17, 9728].
+	 *
+	 * We don't double check because
+	 * - We limited `netdev->min_mtu` to ETH_MIN_MTU.
+	 * - Hypervisor won't allow MTU larger than 9216.
+	 */
+
+	pkt->num_bufs = 0;
+	/* Map the linear portion of skb */
+	{
+		u32 len = skb_headlen(skb);
+		dma_addr_t addr;
+
+		addr = dma_map_single(tx->dev, skb->data, len, DMA_TO_DEVICE);
+		if (unlikely(dma_mapping_error(tx->dev, addr)))
+			goto err;
+
+		dma_unmap_len_set(pkt, len[pkt->num_bufs], len);
+		dma_unmap_addr_set(pkt, dma[pkt->num_bufs], addr);
+		++pkt->num_bufs;
+
+		gve_tx_fill_pkt_desc_dqo(tx, desc_idx, skb, len, addr,
+					 completion_tag,
+					 /*eop=*/shinfo->nr_frags == 0, is_gso);
+	}
+
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		const skb_frag_t *frag = &shinfo->frags[i];
+		bool is_eop = i == (shinfo->nr_frags - 1);
+		u32 len = skb_frag_size(frag);
+		dma_addr_t addr;
+
+		addr = skb_frag_dma_map(tx->dev, frag, 0, len, DMA_TO_DEVICE);
+		if (unlikely(dma_mapping_error(tx->dev, addr)))
+			goto err;
+
+		dma_unmap_len_set(pkt, len[pkt->num_bufs], len);
+		dma_unmap_addr_set(pkt, dma[pkt->num_bufs], addr);
+		++pkt->num_bufs;
+
+		gve_tx_fill_pkt_desc_dqo(tx, desc_idx, skb, len, addr,
+					 completion_tag, is_eop, is_gso);
+	}
+
+	return 0;
+err:
+	for (i = 0; i < pkt->num_bufs; i++) {
+		if (i == 0) {
+			dma_unmap_single(tx->dev,
+					 dma_unmap_addr(pkt, dma[i]),
+					 dma_unmap_len(pkt, len[i]),
+					 DMA_TO_DEVICE);
+		} else {
+			dma_unmap_page(tx->dev,
+				       dma_unmap_addr(pkt, dma[i]),
+				       dma_unmap_len(pkt, len[i]),
+				       DMA_TO_DEVICE);
+		}
+	}
+	pkt->num_bufs = 0;
+	return -1;
+}
+
+/* Tx buffer i corresponds to
+ * qpl_page_id = i / GVE_TX_BUFS_PER_PAGE_DQO
+ * qpl_page_offset = (i % GVE_TX_BUFS_PER_PAGE_DQO) * GVE_TX_BUF_SIZE_DQO
+ */
+static void gve_tx_buf_get_addr(struct gve_tx_ring *tx,
+				s16 index,
+				void **va, dma_addr_t *dma_addr)
+{
+	int page_id = index >> (PAGE_SHIFT - GVE_TX_BUF_SHIFT_DQO);
+	int offset = (index & (GVE_TX_BUFS_PER_PAGE_DQO - 1)) << GVE_TX_BUF_SHIFT_DQO;
+
+	*va = page_address(tx->dqo.qpl->pages[page_id]) + offset;
+	*dma_addr = tx->dqo.qpl->page_buses[page_id] + offset;
+}
+
+static int gve_tx_add_skb_copy_dqo(struct gve_tx_ring *tx,
+				   struct sk_buff *skb,
+				   struct gve_tx_pending_packet_dqo *pkt,
+				   s16 completion_tag,
+				   u32 *desc_idx,
+				   bool is_gso)
+{
+	u32 copy_offset = 0;
+	dma_addr_t dma_addr;
+	u32 copy_len;
+	s16 index;
+	void *va;
+
+	/* Break the packet into buffer size chunks */
+	pkt->num_bufs = 0;
+	while (copy_offset < skb->len) {
+		index = gve_alloc_tx_qpl_buf(tx);
+		if (unlikely(index == -1))
+			goto err;
+
+		gve_tx_buf_get_addr(tx, index, &va, &dma_addr);
+		copy_len = min_t(u32, GVE_TX_BUF_SIZE_DQO,
+				 skb->len - copy_offset);
+		skb_copy_bits(skb, copy_offset, va, copy_len);
+
+		copy_offset += copy_len;
+		dma_sync_single_for_device(tx->dev, dma_addr,
+					   copy_len, DMA_TO_DEVICE);
+		gve_tx_fill_pkt_desc_dqo(tx, desc_idx, skb,
+					 copy_len,
+					 dma_addr,
+					 completion_tag,
+					 copy_offset == skb->len,
+					 is_gso);
+
+		pkt->tx_qpl_buf_ids[pkt->num_bufs] = index;
+		++tx->dqo_tx.alloc_tx_qpl_buf_cnt;
+		++pkt->num_bufs;
+	}
+
+	return 0;
+err:
+	/* Should not be here if gve_has_free_tx_qpl_bufs() check is correct */
+	gve_free_tx_qpl_bufs(tx, pkt);
+	return -ENOMEM;
+}
+
+/* Returns 0 on success, or < 0 on error.
+ *
+ * Before this function is called, the caller must ensure
+ * gve_has_pending_packet(tx) returns true.
+ */
+static int gve_tx_add_skb_dqo(struct gve_tx_ring *tx,
+			      struct sk_buff *skb)
+{
+	const bool is_gso = skb_is_gso(skb);
+	u32 desc_idx = tx->dqo_tx.tail;
+	struct gve_tx_pending_packet_dqo *pkt;
+	struct gve_tx_metadata_dqo metadata;
+	s16 completion_tag;
+
+	pkt = gve_alloc_pending_packet(tx);
+	pkt->skb = skb;
+	completion_tag = pkt - tx->dqo.pending_packets;
+
+	gve_extract_tx_metadata_dqo(skb, &metadata);
+	if (is_gso) {
+		int header_len = gve_prep_tso(skb);
+
+		if (unlikely(header_len < 0))
+			goto err;
+
+		gve_tx_fill_tso_ctx_desc(&tx->dqo.tx_ring[desc_idx].tso_ctx,
+					 skb, &metadata, header_len);
+		desc_idx = (desc_idx + 1) & tx->mask;
+	}
+
+	gve_tx_fill_general_ctx_desc(&tx->dqo.tx_ring[desc_idx].general_ctx,
+				     &metadata);
+	desc_idx = (desc_idx + 1) & tx->mask;
+
+	if (tx->dqo.qpl) {
+		if (gve_tx_add_skb_copy_dqo(tx, skb, pkt,
+					    completion_tag,
+					    &desc_idx, is_gso))
+			goto err;
+	}  else {
+		if (gve_tx_add_skb_no_copy_dqo(tx, skb, pkt,
+					       completion_tag,
+					       &desc_idx, is_gso))
+			goto err;
+	}
+
+	tx->dqo_tx.posted_packet_desc_cnt += pkt->num_bufs;
+
+	/* Commit the changes to our state */
+	tx->dqo_tx.tail = desc_idx;
+
+	/* Request a descriptor completion on the last descriptor of the
+	 * packet if we are allowed to by the HW enforced interval.
+	 */
+	{
+		u32 last_desc_idx = (desc_idx - 1) & tx->mask;
+		u32 last_report_event_interval =
+			(last_desc_idx - tx->dqo_tx.last_re_idx) & tx->mask;
+
+		if (unlikely(last_report_event_interval >=
+			     GVE_TX_MIN_RE_INTERVAL)) {
+			tx->dqo.tx_ring[last_desc_idx].pkt.report_event = true;
+			tx->dqo_tx.last_re_idx = last_desc_idx;
+		}
+	}
+
+	return 0;
+
+err:
+	pkt->skb = NULL;
+	gve_free_pending_packet(tx, pkt);
+
+	return -1;
+}
+
+static int gve_num_descs_per_buf(size_t size)
+{
+	return DIV_ROUND_UP(size, GVE_TX_MAX_BUF_SIZE_DQO);
+}
+
+static int gve_num_buffer_descs_needed(const struct sk_buff *skb)
+{
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	int num_descs;
+	int i;
+
+	num_descs = gve_num_descs_per_buf(skb_headlen(skb));
+
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		unsigned int frag_size = skb_frag_size(&shinfo->frags[i]);
+
+		num_descs += gve_num_descs_per_buf(frag_size);
+	}
+
+	return num_descs;
+}
+
+/* Returns true if HW is capable of sending TSO represented by `skb`.
+ *
+ * Each segment must not span more than GVE_TX_MAX_DATA_DESCS buffers.
+ * - The header is counted as one buffer for every single segment.
+ * - A buffer which is split between two segments is counted for both.
+ * - If a buffer contains both header and payload, it is counted as two buffers.
+ */
+static bool gve_can_send_tso(const struct sk_buff *skb)
+{
+	const int max_bufs_per_seg = GVE_TX_MAX_DATA_DESCS - 1;
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	const int header_len = skb_tcp_all_headers(skb);
+	const int gso_size = shinfo->gso_size;
+	int cur_seg_num_bufs;
+	int cur_seg_size;
+	int i;
+
+	cur_seg_size = skb_headlen(skb) - header_len;
+	cur_seg_num_bufs = cur_seg_size > 0;
+
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		if (cur_seg_size >= gso_size) {
+			cur_seg_size %= gso_size;
+			cur_seg_num_bufs = cur_seg_size > 0;
+		}
+
+		if (unlikely(++cur_seg_num_bufs > max_bufs_per_seg))
+			return false;
+
+		cur_seg_size += skb_frag_size(&shinfo->frags[i]);
+	}
+
+	return true;
+}
+
+/* Attempt to transmit specified SKB.
+ *
+ * Returns 0 if the SKB was transmitted or dropped.
+ * Returns -1 if there is not currently enough space to transmit the SKB.
+ */
+static int gve_try_tx_skb(struct gve_priv *priv, struct gve_tx_ring *tx,
+			  struct sk_buff *skb)
+{
+	int num_buffer_descs;
+	int total_num_descs;
+
+	if (tx->dqo.qpl) {
+		if (skb_is_gso(skb))
+			if (unlikely(ipv6_hopopt_jumbo_remove(skb)))
+				goto drop;
+
+		/* We do not need to verify the number of buffers used per
+		 * packet or per segment in case of TSO as with 2K size buffers
+		 * none of the TX packet rules would be violated.
+		 *
+		 * gve_can_send_tso() checks that each TCP segment of gso_size is
+		 * not distributed over more than 9 SKB frags..
+		 */
+		num_buffer_descs = DIV_ROUND_UP(skb->len, GVE_TX_BUF_SIZE_DQO);
+	} else {
+		if (skb_is_gso(skb)) {
+			/* If TSO doesn't meet HW requirements, attempt to linearize the
+			 * packet.
+			 */
+			if (unlikely(!gve_can_send_tso(skb) &&
+				     skb_linearize(skb) < 0)) {
+				net_err_ratelimited("%s: Failed to transmit TSO packet\n",
+						    priv->dev->name);
+				goto drop;
+			}
+
+			if (unlikely(ipv6_hopopt_jumbo_remove(skb)))
+				goto drop;
+
+			num_buffer_descs = gve_num_buffer_descs_needed(skb);
+		} else {
+			num_buffer_descs = gve_num_buffer_descs_needed(skb);
+
+			if (unlikely(num_buffer_descs > GVE_TX_MAX_DATA_DESCS)) {
+				if (unlikely(skb_linearize(skb) < 0))
+					goto drop;
+
+				num_buffer_descs = 1;
+			}
+		}
+	}
+
+	/* Metadata + (optional TSO) + data descriptors. */
+	total_num_descs = 1 + skb_is_gso(skb) + num_buffer_descs;
+	if (unlikely(gve_maybe_stop_tx_dqo(tx, total_num_descs +
+			GVE_TX_MIN_DESC_PREVENT_CACHE_OVERLAP,
+			num_buffer_descs))) {
+		return -1;
+	}
+
+	if (unlikely(gve_tx_add_skb_dqo(tx, skb) < 0))
+		goto drop;
+
+	netdev_tx_sent_queue(tx->netdev_txq, skb->len);
+	skb_tx_timestamp(skb);
+	return 0;
+
+drop:
+	tx->dropped_pkt++;
+	dev_kfree_skb_any(skb);
+	return 0;
+}
+
+/* Transmit a given skb and ring the doorbell. */
+netdev_tx_t gve_tx_dqo(struct sk_buff *skb, struct net_device *dev)
+{
+	struct gve_priv *priv = netdev_priv(dev);
+	struct gve_tx_ring *tx;
+
+	tx = &priv->tx[skb_get_queue_mapping(skb)];
+	if (unlikely(gve_try_tx_skb(priv, tx, skb) < 0)) {
+		/* We need to ring the txq doorbell -- we have stopped the Tx
+		 * queue for want of resources, but prior calls to gve_tx()
+		 * may have added descriptors without ringing the doorbell.
+		 */
+		gve_tx_put_doorbell_dqo(priv, tx->q_resources, tx->dqo_tx.tail);
+		return NETDEV_TX_BUSY;
+	}
+
+	if (!netif_xmit_stopped(tx->netdev_txq) && netdev_xmit_more())
+		return NETDEV_TX_OK;
+
+	gve_tx_put_doorbell_dqo(priv, tx->q_resources, tx->dqo_tx.tail);
+	return NETDEV_TX_OK;
+}
+
+static void add_to_list(struct gve_tx_ring *tx, struct gve_index_list *list,
+			struct gve_tx_pending_packet_dqo *pending_packet)
+{
+	s16 old_tail, index;
+
+	index = pending_packet - tx->dqo.pending_packets;
+	old_tail = list->tail;
+	list->tail = index;
+	if (old_tail == -1)
+		list->head = index;
+	else
+		tx->dqo.pending_packets[old_tail].next = index;
+
+	pending_packet->next = -1;
+	pending_packet->prev = old_tail;
+}
+
+static void remove_from_list(struct gve_tx_ring *tx,
+			     struct gve_index_list *list,
+			     struct gve_tx_pending_packet_dqo *pkt)
+{
+	s16 prev_index, next_index;
+
+	prev_index = pkt->prev;
+	next_index = pkt->next;
+
+	if (prev_index == -1) {
+		/* Node is head */
+		list->head = next_index;
+	} else {
+		tx->dqo.pending_packets[prev_index].next = next_index;
+	}
+	if (next_index == -1) {
+		/* Node is tail */
+		list->tail = prev_index;
+	} else {
+		tx->dqo.pending_packets[next_index].prev = prev_index;
+	}
+}
+
+static void gve_unmap_packet(struct device *dev,
+			     struct gve_tx_pending_packet_dqo *pkt)
+{
+	int i;
+
+	/* SKB linear portion is guaranteed to be mapped */
+	dma_unmap_single(dev, dma_unmap_addr(pkt, dma[0]),
+			 dma_unmap_len(pkt, len[0]), DMA_TO_DEVICE);
+	for (i = 1; i < pkt->num_bufs; i++) {
+		dma_unmap_page(dev, dma_unmap_addr(pkt, dma[i]),
+			       dma_unmap_len(pkt, len[i]), DMA_TO_DEVICE);
+	}
+	pkt->num_bufs = 0;
+}
+
+/* Completion types and expected behavior:
+ * No Miss compl + Packet compl = Packet completed normally.
+ * Miss compl + Re-inject compl = Packet completed normally.
+ * No Miss compl + Re-inject compl = Skipped i.e. packet not completed.
+ * Miss compl + Packet compl = Skipped i.e. packet not completed.
+ */
+static void gve_handle_packet_completion(struct gve_priv *priv,
+					 struct gve_tx_ring *tx, bool is_napi,
+					 u16 compl_tag, u64 *bytes, u64 *pkts,
+					 bool is_reinjection)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+
+	if (unlikely(compl_tag >= tx->dqo.num_pending_packets)) {
+		net_err_ratelimited("%s: Invalid TX completion tag: %d\n",
+				    priv->dev->name, (int)compl_tag);
+		return;
+	}
+
+	pending_packet = &tx->dqo.pending_packets[compl_tag];
+
+	if (unlikely(is_reinjection)) {
+		if (unlikely(pending_packet->state ==
+			     GVE_PACKET_STATE_TIMED_OUT_COMPL)) {
+			net_err_ratelimited("%s: Re-injection completion: %d received after timeout.\n",
+					    priv->dev->name, (int)compl_tag);
+			/* Packet was already completed as a result of timeout,
+			 * so just remove from list and free pending packet.
+			 */
+			remove_from_list(tx,
+					 &tx->dqo_compl.timed_out_completions,
+					 pending_packet);
+			gve_free_pending_packet(tx, pending_packet);
+			return;
+		}
+		if (unlikely(pending_packet->state !=
+			     GVE_PACKET_STATE_PENDING_REINJECT_COMPL)) {
+			/* No outstanding miss completion but packet allocated
+			 * implies packet receives a re-injection completion
+			 * without a prior miss completion. Return without
+			 * completing the packet.
+			 */
+			net_err_ratelimited("%s: Re-injection completion received without corresponding miss completion: %d\n",
+					    priv->dev->name, (int)compl_tag);
+			return;
+		}
+		remove_from_list(tx, &tx->dqo_compl.miss_completions,
+				 pending_packet);
+	} else {
+		/* Packet is allocated but not a pending data completion. */
+		if (unlikely(pending_packet->state !=
+			     GVE_PACKET_STATE_PENDING_DATA_COMPL)) {
+			net_err_ratelimited("%s: No pending data completion: %d\n",
+					    priv->dev->name, (int)compl_tag);
+			return;
+		}
+	}
+	tx->dqo_tx.completed_packet_desc_cnt += pending_packet->num_bufs;
+	if (tx->dqo.qpl)
+		gve_free_tx_qpl_bufs(tx, pending_packet);
+	else
+		gve_unmap_packet(tx->dev, pending_packet);
+
+	*bytes += pending_packet->skb->len;
+	(*pkts)++;
+	napi_consume_skb(pending_packet->skb, is_napi);
+	pending_packet->skb = NULL;
+	gve_free_pending_packet(tx, pending_packet);
+}
+
+static void gve_handle_miss_completion(struct gve_priv *priv,
+				       struct gve_tx_ring *tx, u16 compl_tag,
+				       u64 *bytes, u64 *pkts)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+
+	if (unlikely(compl_tag >= tx->dqo.num_pending_packets)) {
+		net_err_ratelimited("%s: Invalid TX completion tag: %d\n",
+				    priv->dev->name, (int)compl_tag);
+		return;
+	}
+
+	pending_packet = &tx->dqo.pending_packets[compl_tag];
+	if (unlikely(pending_packet->state !=
+				GVE_PACKET_STATE_PENDING_DATA_COMPL)) {
+		net_err_ratelimited("%s: Unexpected packet state: %d for completion tag : %d\n",
+				    priv->dev->name, (int)pending_packet->state,
+				    (int)compl_tag);
+		return;
+	}
+
+	pending_packet->state = GVE_PACKET_STATE_PENDING_REINJECT_COMPL;
+	/* jiffies can wraparound but time comparisons can handle overflows. */
+	pending_packet->timeout_jiffies =
+			jiffies +
+			msecs_to_jiffies(GVE_REINJECT_COMPL_TIMEOUT *
+					 MSEC_PER_SEC);
+	add_to_list(tx, &tx->dqo_compl.miss_completions, pending_packet);
+
+	*bytes += pending_packet->skb->len;
+	(*pkts)++;
+}
+
+static void remove_miss_completions(struct gve_priv *priv,
+				    struct gve_tx_ring *tx)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	s16 next_index;
+
+	next_index = tx->dqo_compl.miss_completions.head;
+	while (next_index != -1) {
+		pending_packet = &tx->dqo.pending_packets[next_index];
+		next_index = pending_packet->next;
+		/* Break early because packets should timeout in order. */
+		if (time_is_after_jiffies(pending_packet->timeout_jiffies))
+			break;
+
+		remove_from_list(tx, &tx->dqo_compl.miss_completions,
+				 pending_packet);
+		/* Unmap/free TX buffers and free skb but do not unallocate packet i.e.
+		 * the completion tag is not freed to ensure that the driver
+		 * can take appropriate action if a corresponding valid
+		 * completion is received later.
+		 */
+		if (tx->dqo.qpl)
+			gve_free_tx_qpl_bufs(tx, pending_packet);
+		else
+			gve_unmap_packet(tx->dev, pending_packet);
+
+		/* This indicates the packet was dropped. */
+		dev_kfree_skb_any(pending_packet->skb);
+		pending_packet->skb = NULL;
+		tx->dropped_pkt++;
+		net_err_ratelimited("%s: No reinjection completion was received for: %d.\n",
+				    priv->dev->name,
+				    (int)(pending_packet - tx->dqo.pending_packets));
+
+		pending_packet->state = GVE_PACKET_STATE_TIMED_OUT_COMPL;
+		pending_packet->timeout_jiffies =
+				jiffies +
+				msecs_to_jiffies(GVE_DEALLOCATE_COMPL_TIMEOUT *
+						 MSEC_PER_SEC);
+		/* Maintain pending packet in another list so the packet can be
+		 * unallocated at a later time.
+		 */
+		add_to_list(tx, &tx->dqo_compl.timed_out_completions,
+			    pending_packet);
+	}
+}
+
+static void remove_timed_out_completions(struct gve_priv *priv,
+					 struct gve_tx_ring *tx)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	s16 next_index;
+
+	next_index = tx->dqo_compl.timed_out_completions.head;
+	while (next_index != -1) {
+		pending_packet = &tx->dqo.pending_packets[next_index];
+		next_index = pending_packet->next;
+		/* Break early because packets should timeout in order. */
+		if (time_is_after_jiffies(pending_packet->timeout_jiffies))
+			break;
+
+		remove_from_list(tx, &tx->dqo_compl.timed_out_completions,
+				 pending_packet);
+		gve_free_pending_packet(tx, pending_packet);
+	}
+}
+
+int gve_clean_tx_done_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
+			  struct napi_struct *napi)
+{
+	u64 reinject_compl_bytes = 0;
+	u64 reinject_compl_pkts = 0;
+	int num_descs_cleaned = 0;
+	u64 miss_compl_bytes = 0;
+	u64 miss_compl_pkts = 0;
+	u64 pkt_compl_bytes = 0;
+	u64 pkt_compl_pkts = 0;
+
+	/* Limit in order to avoid blocking for too long */
+	while (!napi || pkt_compl_pkts < napi->weight) {
+		struct gve_tx_compl_desc *compl_desc =
+			&tx->dqo.compl_ring[tx->dqo_compl.head];
+		u16 type;
+
+		if (compl_desc->generation == tx->dqo_compl.cur_gen_bit)
+			break;
+
+		/* Prefetch the next descriptor. */
+		prefetch(&tx->dqo.compl_ring[(tx->dqo_compl.head + 1) &
+				tx->dqo.complq_mask]);
+
+		/* Do not read data until we own the descriptor */
+		dma_rmb();
+		type = compl_desc->type;
+
+		if (type == GVE_COMPL_TYPE_DQO_DESC) {
+			/* This is the last descriptor fetched by HW plus one */
+			u16 tx_head = le16_to_cpu(compl_desc->tx_head);
+
+			atomic_set_release(&tx->dqo_compl.hw_tx_head, tx_head);
+		} else if (type == GVE_COMPL_TYPE_DQO_PKT) {
+			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
+			if (compl_tag & GVE_ALT_MISS_COMPL_BIT) {
+				compl_tag &= ~GVE_ALT_MISS_COMPL_BIT;
+				gve_handle_miss_completion(priv, tx, compl_tag,
+							   &miss_compl_bytes,
+							   &miss_compl_pkts);
+			} else {
+				gve_handle_packet_completion(priv, tx, !!napi,
+							     compl_tag,
+							     &pkt_compl_bytes,
+							     &pkt_compl_pkts,
+							     false);
+			}
+		} else if (type == GVE_COMPL_TYPE_DQO_MISS) {
+			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
+
+			gve_handle_miss_completion(priv, tx, compl_tag,
+						   &miss_compl_bytes,
+						   &miss_compl_pkts);
+		} else if (type == GVE_COMPL_TYPE_DQO_REINJECTION) {
+			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
+
+			gve_handle_packet_completion(priv, tx, !!napi,
+						     compl_tag,
+						     &reinject_compl_bytes,
+						     &reinject_compl_pkts,
+						     true);
+		}
+
+		tx->dqo_compl.head =
+			(tx->dqo_compl.head + 1) & tx->dqo.complq_mask;
+		/* Flip the generation bit when we wrap around */
+		tx->dqo_compl.cur_gen_bit ^= tx->dqo_compl.head == 0;
+		num_descs_cleaned++;
+	}
+
+	netdev_tx_completed_queue(tx->netdev_txq,
+				  pkt_compl_pkts + miss_compl_pkts,
+				  pkt_compl_bytes + miss_compl_bytes);
+
+	remove_miss_completions(priv, tx);
+	remove_timed_out_completions(priv, tx);
+
+	u64_stats_update_begin(&tx->statss);
+	tx->bytes_done += pkt_compl_bytes + reinject_compl_bytes;
+	tx->pkt_done += pkt_compl_pkts + reinject_compl_pkts;
+	u64_stats_update_end(&tx->statss);
+	return num_descs_cleaned;
+}
+
+bool gve_tx_poll_dqo(struct gve_notify_block *block, bool do_clean)
+{
+	struct gve_tx_compl_desc *compl_desc;
+	struct gve_tx_ring *tx = block->tx;
+	struct gve_priv *priv = block->priv;
+
+	if (do_clean) {
+		int num_descs_cleaned = gve_clean_tx_done_dqo(priv, tx,
+							      &block->napi);
+
+		/* Sync with queue being stopped in `gve_maybe_stop_tx_dqo()` */
+		mb();
+
+		if (netif_tx_queue_stopped(tx->netdev_txq) &&
+		    num_descs_cleaned > 0) {
+			tx->wake_queue++;
+			netif_tx_wake_queue(tx->netdev_txq);
+		}
+	}
+
+	/* Return true if we still have work. */
+	compl_desc = &tx->dqo.compl_ring[tx->dqo_compl.head];
+	return compl_desc->generation != tx->dqo_compl.cur_gen_bit;
+}