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|
// 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;
}
netdev_features_t gve_features_check_dqo(struct sk_buff *skb,
struct net_device *dev,
netdev_features_t features)
{
if (skb_is_gso(skb) && !gve_can_send_tso(skb))
return features & ~NETIF_F_GSO_MASK;
return features;
}
/* 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 (skb_is_gso(skb) && unlikely(ipv6_hopopt_jumbo_remove(skb)))
goto drop;
if (tx->dqo.qpl) {
/* 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 {
num_buffer_descs = gve_num_buffer_descs_needed(skb);
if (!skb_is_gso(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;
}
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