1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
2 /* Google virtual Ethernet (gve) driver
3 *
4 * Copyright (C) 2015-2021 Google, Inc.
5 */
6
7 #include "gve.h"
8 #include "gve_adminq.h"
9 #include "gve_utils.h"
10 #include <linux/etherdevice.h>
11
gve_rx_free_buffer(struct device * dev,struct gve_rx_slot_page_info * page_info,union gve_rx_data_slot * data_slot)12 static void gve_rx_free_buffer(struct device *dev,
13 struct gve_rx_slot_page_info *page_info,
14 union gve_rx_data_slot *data_slot)
15 {
16 dma_addr_t dma = (dma_addr_t)(be64_to_cpu(data_slot->addr) &
17 GVE_DATA_SLOT_ADDR_PAGE_MASK);
18
19 page_ref_sub(page_info->page, page_info->pagecnt_bias - 1);
20 gve_free_page(dev, page_info->page, dma, DMA_FROM_DEVICE);
21 }
22
gve_rx_unfill_pages(struct gve_priv * priv,struct gve_rx_ring * rx)23 static void gve_rx_unfill_pages(struct gve_priv *priv, struct gve_rx_ring *rx)
24 {
25 u32 slots = rx->mask + 1;
26 int i;
27
28 if (rx->data.raw_addressing) {
29 for (i = 0; i < slots; i++)
30 gve_rx_free_buffer(&priv->pdev->dev, &rx->data.page_info[i],
31 &rx->data.data_ring[i]);
32 } else {
33 for (i = 0; i < slots; i++)
34 page_ref_sub(rx->data.page_info[i].page,
35 rx->data.page_info[i].pagecnt_bias - 1);
36 gve_unassign_qpl(priv, rx->data.qpl->id);
37 rx->data.qpl = NULL;
38 }
39 kvfree(rx->data.page_info);
40 rx->data.page_info = NULL;
41 }
42
gve_rx_free_ring(struct gve_priv * priv,int idx)43 static void gve_rx_free_ring(struct gve_priv *priv, int idx)
44 {
45 struct gve_rx_ring *rx = &priv->rx[idx];
46 struct device *dev = &priv->pdev->dev;
47 u32 slots = rx->mask + 1;
48 size_t bytes;
49
50 gve_rx_remove_from_block(priv, idx);
51
52 bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
53 dma_free_coherent(dev, bytes, rx->desc.desc_ring, rx->desc.bus);
54 rx->desc.desc_ring = NULL;
55
56 dma_free_coherent(dev, sizeof(*rx->q_resources),
57 rx->q_resources, rx->q_resources_bus);
58 rx->q_resources = NULL;
59
60 gve_rx_unfill_pages(priv, rx);
61
62 bytes = sizeof(*rx->data.data_ring) * slots;
63 dma_free_coherent(dev, bytes, rx->data.data_ring,
64 rx->data.data_bus);
65 rx->data.data_ring = NULL;
66 netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
67 }
68
gve_setup_rx_buffer(struct gve_rx_slot_page_info * page_info,dma_addr_t addr,struct page * page,__be64 * slot_addr)69 static void gve_setup_rx_buffer(struct gve_rx_slot_page_info *page_info,
70 dma_addr_t addr, struct page *page, __be64 *slot_addr)
71 {
72 page_info->page = page;
73 page_info->page_offset = 0;
74 page_info->page_address = page_address(page);
75 *slot_addr = cpu_to_be64(addr);
76 /* The page already has 1 ref */
77 page_ref_add(page, INT_MAX - 1);
78 page_info->pagecnt_bias = INT_MAX;
79 }
80
gve_rx_alloc_buffer(struct gve_priv * priv,struct device * dev,struct gve_rx_slot_page_info * page_info,union gve_rx_data_slot * data_slot)81 static int gve_rx_alloc_buffer(struct gve_priv *priv, struct device *dev,
82 struct gve_rx_slot_page_info *page_info,
83 union gve_rx_data_slot *data_slot)
84 {
85 struct page *page;
86 dma_addr_t dma;
87 int err;
88
89 err = gve_alloc_page(priv, dev, &page, &dma, DMA_FROM_DEVICE,
90 GFP_ATOMIC);
91 if (err)
92 return err;
93
94 gve_setup_rx_buffer(page_info, dma, page, &data_slot->addr);
95 return 0;
96 }
97
gve_prefill_rx_pages(struct gve_rx_ring * rx)98 static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
99 {
100 struct gve_priv *priv = rx->gve;
101 u32 slots;
102 int err;
103 int i;
104
105 /* Allocate one page per Rx queue slot. Each page is split into two
106 * packet buffers, when possible we "page flip" between the two.
107 */
108 slots = rx->mask + 1;
109
110 rx->data.page_info = kvzalloc(slots *
111 sizeof(*rx->data.page_info), GFP_KERNEL);
112 if (!rx->data.page_info)
113 return -ENOMEM;
114
115 if (!rx->data.raw_addressing) {
116 rx->data.qpl = gve_assign_rx_qpl(priv);
117 if (!rx->data.qpl) {
118 kvfree(rx->data.page_info);
119 rx->data.page_info = NULL;
120 return -ENOMEM;
121 }
122 }
123 for (i = 0; i < slots; i++) {
124 if (!rx->data.raw_addressing) {
125 struct page *page = rx->data.qpl->pages[i];
126 dma_addr_t addr = i * PAGE_SIZE;
127
128 gve_setup_rx_buffer(&rx->data.page_info[i], addr, page,
129 &rx->data.data_ring[i].qpl_offset);
130 continue;
131 }
132 err = gve_rx_alloc_buffer(priv, &priv->pdev->dev, &rx->data.page_info[i],
133 &rx->data.data_ring[i]);
134 if (err)
135 goto alloc_err;
136 }
137
138 return slots;
139 alloc_err:
140 while (i--)
141 gve_rx_free_buffer(&priv->pdev->dev,
142 &rx->data.page_info[i],
143 &rx->data.data_ring[i]);
144 return err;
145 }
146
gve_rx_ctx_clear(struct gve_rx_ctx * ctx)147 static void gve_rx_ctx_clear(struct gve_rx_ctx *ctx)
148 {
149 ctx->curr_frag_cnt = 0;
150 ctx->total_expected_size = 0;
151 ctx->expected_frag_cnt = 0;
152 ctx->skb_head = NULL;
153 ctx->skb_tail = NULL;
154 ctx->reuse_frags = false;
155 }
156
gve_rx_alloc_ring(struct gve_priv * priv,int idx)157 static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
158 {
159 struct gve_rx_ring *rx = &priv->rx[idx];
160 struct device *hdev = &priv->pdev->dev;
161 u32 slots, npages;
162 int filled_pages;
163 size_t bytes;
164 int err;
165
166 netif_dbg(priv, drv, priv->dev, "allocating rx ring\n");
167 /* Make sure everything is zeroed to start with */
168 memset(rx, 0, sizeof(*rx));
169
170 rx->gve = priv;
171 rx->q_num = idx;
172
173 slots = priv->rx_data_slot_cnt;
174 rx->mask = slots - 1;
175 rx->data.raw_addressing = priv->queue_format == GVE_GQI_RDA_FORMAT;
176
177 /* alloc rx data ring */
178 bytes = sizeof(*rx->data.data_ring) * slots;
179 rx->data.data_ring = dma_alloc_coherent(hdev, bytes,
180 &rx->data.data_bus,
181 GFP_KERNEL);
182 if (!rx->data.data_ring)
183 return -ENOMEM;
184 filled_pages = gve_prefill_rx_pages(rx);
185 if (filled_pages < 0) {
186 err = -ENOMEM;
187 goto abort_with_slots;
188 }
189 rx->fill_cnt = filled_pages;
190 /* Ensure data ring slots (packet buffers) are visible. */
191 dma_wmb();
192
193 /* Alloc gve_queue_resources */
194 rx->q_resources =
195 dma_alloc_coherent(hdev,
196 sizeof(*rx->q_resources),
197 &rx->q_resources_bus,
198 GFP_KERNEL);
199 if (!rx->q_resources) {
200 err = -ENOMEM;
201 goto abort_filled;
202 }
203 netif_dbg(priv, drv, priv->dev, "rx[%d]->data.data_bus=%lx\n", idx,
204 (unsigned long)rx->data.data_bus);
205
206 /* alloc rx desc ring */
207 bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
208 npages = bytes / PAGE_SIZE;
209 if (npages * PAGE_SIZE != bytes) {
210 err = -EIO;
211 goto abort_with_q_resources;
212 }
213
214 rx->desc.desc_ring = dma_alloc_coherent(hdev, bytes, &rx->desc.bus,
215 GFP_KERNEL);
216 if (!rx->desc.desc_ring) {
217 err = -ENOMEM;
218 goto abort_with_q_resources;
219 }
220 rx->cnt = 0;
221 rx->db_threshold = priv->rx_desc_cnt / 2;
222 rx->desc.seqno = 1;
223
224 /* Allocating half-page buffers allows page-flipping which is faster
225 * than copying or allocating new pages.
226 */
227 rx->packet_buffer_size = PAGE_SIZE / 2;
228 gve_rx_ctx_clear(&rx->ctx);
229 gve_rx_add_to_block(priv, idx);
230
231 return 0;
232
233 abort_with_q_resources:
234 dma_free_coherent(hdev, sizeof(*rx->q_resources),
235 rx->q_resources, rx->q_resources_bus);
236 rx->q_resources = NULL;
237 abort_filled:
238 gve_rx_unfill_pages(priv, rx);
239 abort_with_slots:
240 bytes = sizeof(*rx->data.data_ring) * slots;
241 dma_free_coherent(hdev, bytes, rx->data.data_ring, rx->data.data_bus);
242 rx->data.data_ring = NULL;
243
244 return err;
245 }
246
gve_rx_alloc_rings(struct gve_priv * priv)247 int gve_rx_alloc_rings(struct gve_priv *priv)
248 {
249 int err = 0;
250 int i;
251
252 for (i = 0; i < priv->rx_cfg.num_queues; i++) {
253 err = gve_rx_alloc_ring(priv, i);
254 if (err) {
255 netif_err(priv, drv, priv->dev,
256 "Failed to alloc rx ring=%d: err=%d\n",
257 i, err);
258 break;
259 }
260 }
261 /* Unallocate if there was an error */
262 if (err) {
263 int j;
264
265 for (j = 0; j < i; j++)
266 gve_rx_free_ring(priv, j);
267 }
268 return err;
269 }
270
gve_rx_free_rings_gqi(struct gve_priv * priv)271 void gve_rx_free_rings_gqi(struct gve_priv *priv)
272 {
273 int i;
274
275 for (i = 0; i < priv->rx_cfg.num_queues; i++)
276 gve_rx_free_ring(priv, i);
277 }
278
gve_rx_write_doorbell(struct gve_priv * priv,struct gve_rx_ring * rx)279 void gve_rx_write_doorbell(struct gve_priv *priv, struct gve_rx_ring *rx)
280 {
281 u32 db_idx = be32_to_cpu(rx->q_resources->db_index);
282
283 iowrite32be(rx->fill_cnt, &priv->db_bar2[db_idx]);
284 }
285
gve_rss_type(__be16 pkt_flags)286 static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
287 {
288 if (likely(pkt_flags & (GVE_RXF_TCP | GVE_RXF_UDP)))
289 return PKT_HASH_TYPE_L4;
290 if (pkt_flags & (GVE_RXF_IPV4 | GVE_RXF_IPV6))
291 return PKT_HASH_TYPE_L3;
292 return PKT_HASH_TYPE_L2;
293 }
294
gve_rx_ctx_padding(struct gve_rx_ctx * ctx)295 static u16 gve_rx_ctx_padding(struct gve_rx_ctx *ctx)
296 {
297 return (ctx->curr_frag_cnt == 0) ? GVE_RX_PAD : 0;
298 }
299
gve_rx_add_frags(struct napi_struct * napi,struct gve_rx_slot_page_info * page_info,u16 packet_buffer_size,u16 len,struct gve_rx_ctx * ctx)300 static struct sk_buff *gve_rx_add_frags(struct napi_struct *napi,
301 struct gve_rx_slot_page_info *page_info,
302 u16 packet_buffer_size, u16 len,
303 struct gve_rx_ctx *ctx)
304 {
305 u32 offset = page_info->page_offset + gve_rx_ctx_padding(ctx);
306 struct sk_buff *skb;
307
308 if (!ctx->skb_head)
309 ctx->skb_head = napi_get_frags(napi);
310
311 if (unlikely(!ctx->skb_head))
312 return NULL;
313
314 skb = ctx->skb_head;
315 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page_info->page,
316 offset, len, packet_buffer_size);
317
318 return skb;
319 }
320
gve_rx_flip_buff(struct gve_rx_slot_page_info * page_info,__be64 * slot_addr)321 static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info, __be64 *slot_addr)
322 {
323 const __be64 offset = cpu_to_be64(PAGE_SIZE / 2);
324
325 /* "flip" to other packet buffer on this page */
326 page_info->page_offset ^= PAGE_SIZE / 2;
327 *(slot_addr) ^= offset;
328 }
329
gve_rx_can_recycle_buffer(struct gve_rx_slot_page_info * page_info)330 static int gve_rx_can_recycle_buffer(struct gve_rx_slot_page_info *page_info)
331 {
332 int pagecount = page_count(page_info->page);
333
334 /* This page is not being used by any SKBs - reuse */
335 if (pagecount == page_info->pagecnt_bias)
336 return 1;
337 /* This page is still being used by an SKB - we can't reuse */
338 else if (pagecount > page_info->pagecnt_bias)
339 return 0;
340 WARN(pagecount < page_info->pagecnt_bias,
341 "Pagecount should never be less than the bias.");
342 return -1;
343 }
344
345 static struct sk_buff *
gve_rx_raw_addressing(struct device * dev,struct net_device * netdev,struct gve_rx_slot_page_info * page_info,u16 len,struct napi_struct * napi,union gve_rx_data_slot * data_slot,u16 packet_buffer_size,struct gve_rx_ctx * ctx)346 gve_rx_raw_addressing(struct device *dev, struct net_device *netdev,
347 struct gve_rx_slot_page_info *page_info, u16 len,
348 struct napi_struct *napi,
349 union gve_rx_data_slot *data_slot,
350 u16 packet_buffer_size, struct gve_rx_ctx *ctx)
351 {
352 struct sk_buff *skb = gve_rx_add_frags(napi, page_info, packet_buffer_size, len, ctx);
353
354 if (!skb)
355 return NULL;
356
357 /* Optimistically stop the kernel from freeing the page.
358 * We will check again in refill to determine if we need to alloc a
359 * new page.
360 */
361 gve_dec_pagecnt_bias(page_info);
362
363 return skb;
364 }
365
366 static struct sk_buff *
gve_rx_qpl(struct device * dev,struct net_device * netdev,struct gve_rx_ring * rx,struct gve_rx_slot_page_info * page_info,u16 len,struct napi_struct * napi,union gve_rx_data_slot * data_slot)367 gve_rx_qpl(struct device *dev, struct net_device *netdev,
368 struct gve_rx_ring *rx, struct gve_rx_slot_page_info *page_info,
369 u16 len, struct napi_struct *napi,
370 union gve_rx_data_slot *data_slot)
371 {
372 struct gve_rx_ctx *ctx = &rx->ctx;
373 struct sk_buff *skb;
374
375 /* if raw_addressing mode is not enabled gvnic can only receive into
376 * registered segments. If the buffer can't be recycled, our only
377 * choice is to copy the data out of it so that we can return it to the
378 * device.
379 */
380 if (ctx->reuse_frags) {
381 skb = gve_rx_add_frags(napi, page_info, rx->packet_buffer_size, len, ctx);
382 /* No point in recycling if we didn't get the skb */
383 if (skb) {
384 /* Make sure that the page isn't freed. */
385 gve_dec_pagecnt_bias(page_info);
386 gve_rx_flip_buff(page_info, &data_slot->qpl_offset);
387 }
388 } else {
389 const u16 padding = gve_rx_ctx_padding(ctx);
390
391 skb = gve_rx_copy(netdev, napi, page_info, len, padding, ctx);
392 if (skb) {
393 u64_stats_update_begin(&rx->statss);
394 rx->rx_frag_copy_cnt++;
395 u64_stats_update_end(&rx->statss);
396 }
397 }
398 return skb;
399 }
400
401 #define GVE_PKTCONT_BIT_IS_SET(x) (GVE_RXF_PKT_CONT & (x))
gve_rx_get_fragment_size(struct gve_rx_ctx * ctx,struct gve_rx_desc * desc)402 static u16 gve_rx_get_fragment_size(struct gve_rx_ctx *ctx, struct gve_rx_desc *desc)
403 {
404 return be16_to_cpu(desc->len) - gve_rx_ctx_padding(ctx);
405 }
406
gve_rx_ctx_init(struct gve_rx_ctx * ctx,struct gve_rx_ring * rx)407 static bool gve_rx_ctx_init(struct gve_rx_ctx *ctx, struct gve_rx_ring *rx)
408 {
409 bool qpl_mode = !rx->data.raw_addressing, packet_size_error = false;
410 bool buffer_error = false, desc_error = false, seqno_error = false;
411 struct gve_rx_slot_page_info *page_info;
412 struct gve_priv *priv = rx->gve;
413 u32 idx = rx->cnt & rx->mask;
414 bool reuse_frags, can_flip;
415 struct gve_rx_desc *desc;
416 u16 packet_size = 0;
417 u16 n_frags = 0;
418 int recycle;
419
420 /** In QPL mode, we only flip buffers when all buffers containing the packet
421 * can be flipped. RDA can_flip decisions will be made later, per frag.
422 */
423 can_flip = qpl_mode;
424 reuse_frags = can_flip;
425 do {
426 u16 frag_size;
427
428 n_frags++;
429 desc = &rx->desc.desc_ring[idx];
430 desc_error = unlikely(desc->flags_seq & GVE_RXF_ERR) || desc_error;
431 if (GVE_SEQNO(desc->flags_seq) != rx->desc.seqno) {
432 seqno_error = true;
433 netdev_warn(priv->dev,
434 "RX seqno error: want=%d, got=%d, dropping packet and scheduling reset.",
435 rx->desc.seqno, GVE_SEQNO(desc->flags_seq));
436 }
437 frag_size = be16_to_cpu(desc->len);
438 packet_size += frag_size;
439 if (frag_size > rx->packet_buffer_size) {
440 packet_size_error = true;
441 netdev_warn(priv->dev,
442 "RX fragment error: packet_buffer_size=%d, frag_size=%d, dropping packet.",
443 rx->packet_buffer_size, be16_to_cpu(desc->len));
444 }
445 page_info = &rx->data.page_info[idx];
446 if (can_flip) {
447 recycle = gve_rx_can_recycle_buffer(page_info);
448 reuse_frags = reuse_frags && recycle > 0;
449 buffer_error = buffer_error || unlikely(recycle < 0);
450 }
451 idx = (idx + 1) & rx->mask;
452 rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
453 } while (GVE_PKTCONT_BIT_IS_SET(desc->flags_seq));
454
455 prefetch(rx->desc.desc_ring + idx);
456
457 ctx->curr_frag_cnt = 0;
458 ctx->total_expected_size = packet_size - GVE_RX_PAD;
459 ctx->expected_frag_cnt = n_frags;
460 ctx->skb_head = NULL;
461 ctx->reuse_frags = reuse_frags;
462
463 if (ctx->expected_frag_cnt > 1) {
464 u64_stats_update_begin(&rx->statss);
465 rx->rx_cont_packet_cnt++;
466 u64_stats_update_end(&rx->statss);
467 }
468 if (ctx->total_expected_size > priv->rx_copybreak && !ctx->reuse_frags && qpl_mode) {
469 u64_stats_update_begin(&rx->statss);
470 rx->rx_copied_pkt++;
471 u64_stats_update_end(&rx->statss);
472 }
473
474 if (unlikely(buffer_error || seqno_error || packet_size_error)) {
475 gve_schedule_reset(priv);
476 return false;
477 }
478
479 if (unlikely(desc_error)) {
480 u64_stats_update_begin(&rx->statss);
481 rx->rx_desc_err_dropped_pkt++;
482 u64_stats_update_end(&rx->statss);
483 return false;
484 }
485 return true;
486 }
487
gve_rx_skb(struct gve_priv * priv,struct gve_rx_ring * rx,struct gve_rx_slot_page_info * page_info,struct napi_struct * napi,u16 len,union gve_rx_data_slot * data_slot)488 static struct sk_buff *gve_rx_skb(struct gve_priv *priv, struct gve_rx_ring *rx,
489 struct gve_rx_slot_page_info *page_info, struct napi_struct *napi,
490 u16 len, union gve_rx_data_slot *data_slot)
491 {
492 struct net_device *netdev = priv->dev;
493 struct gve_rx_ctx *ctx = &rx->ctx;
494 struct sk_buff *skb = NULL;
495
496 if (len <= priv->rx_copybreak && ctx->expected_frag_cnt == 1) {
497 /* Just copy small packets */
498 skb = gve_rx_copy(netdev, napi, page_info, len, GVE_RX_PAD, ctx);
499 if (skb) {
500 u64_stats_update_begin(&rx->statss);
501 rx->rx_copied_pkt++;
502 rx->rx_frag_copy_cnt++;
503 rx->rx_copybreak_pkt++;
504 u64_stats_update_end(&rx->statss);
505 }
506 } else {
507 if (rx->data.raw_addressing) {
508 int recycle = gve_rx_can_recycle_buffer(page_info);
509
510 if (unlikely(recycle < 0)) {
511 gve_schedule_reset(priv);
512 return NULL;
513 }
514 page_info->can_flip = recycle;
515 if (page_info->can_flip) {
516 u64_stats_update_begin(&rx->statss);
517 rx->rx_frag_flip_cnt++;
518 u64_stats_update_end(&rx->statss);
519 }
520 skb = gve_rx_raw_addressing(&priv->pdev->dev, netdev,
521 page_info, len, napi,
522 data_slot,
523 rx->packet_buffer_size, ctx);
524 } else {
525 if (ctx->reuse_frags) {
526 u64_stats_update_begin(&rx->statss);
527 rx->rx_frag_flip_cnt++;
528 u64_stats_update_end(&rx->statss);
529 }
530 skb = gve_rx_qpl(&priv->pdev->dev, netdev, rx,
531 page_info, len, napi, data_slot);
532 }
533 }
534 return skb;
535 }
536
gve_rx(struct gve_rx_ring * rx,netdev_features_t feat,u64 * packet_size_bytes,u32 * work_done)537 static bool gve_rx(struct gve_rx_ring *rx, netdev_features_t feat,
538 u64 *packet_size_bytes, u32 *work_done)
539 {
540 struct gve_rx_slot_page_info *page_info;
541 struct gve_rx_ctx *ctx = &rx->ctx;
542 union gve_rx_data_slot *data_slot;
543 struct gve_priv *priv = rx->gve;
544 struct gve_rx_desc *first_desc;
545 struct sk_buff *skb = NULL;
546 struct gve_rx_desc *desc;
547 struct napi_struct *napi;
548 dma_addr_t page_bus;
549 u32 work_cnt = 0;
550 void *va;
551 u32 idx;
552 u16 len;
553
554 idx = rx->cnt & rx->mask;
555 first_desc = &rx->desc.desc_ring[idx];
556 desc = first_desc;
557 napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
558
559 if (unlikely(!gve_rx_ctx_init(ctx, rx)))
560 goto skb_alloc_fail;
561
562 while (ctx->curr_frag_cnt < ctx->expected_frag_cnt) {
563 /* Prefetch two packet buffers ahead, we will need it soon. */
564 page_info = &rx->data.page_info[(idx + 2) & rx->mask];
565 va = page_info->page_address + page_info->page_offset;
566
567 prefetch(page_info->page); /* Kernel page struct. */
568 prefetch(va); /* Packet header. */
569 prefetch(va + 64); /* Next cacheline too. */
570
571 len = gve_rx_get_fragment_size(ctx, desc);
572
573 page_info = &rx->data.page_info[idx];
574 data_slot = &rx->data.data_ring[idx];
575 page_bus = rx->data.raw_addressing ?
576 be64_to_cpu(data_slot->addr) - page_info->page_offset :
577 rx->data.qpl->page_buses[idx];
578 dma_sync_single_for_cpu(&priv->pdev->dev, page_bus, PAGE_SIZE, DMA_FROM_DEVICE);
579
580 skb = gve_rx_skb(priv, rx, page_info, napi, len, data_slot);
581 if (!skb) {
582 u64_stats_update_begin(&rx->statss);
583 rx->rx_skb_alloc_fail++;
584 u64_stats_update_end(&rx->statss);
585 goto skb_alloc_fail;
586 }
587
588 ctx->curr_frag_cnt++;
589 rx->cnt++;
590 idx = rx->cnt & rx->mask;
591 work_cnt++;
592 desc = &rx->desc.desc_ring[idx];
593 }
594
595 if (likely(feat & NETIF_F_RXCSUM)) {
596 /* NIC passes up the partial sum */
597 if (first_desc->csum)
598 skb->ip_summed = CHECKSUM_COMPLETE;
599 else
600 skb->ip_summed = CHECKSUM_NONE;
601 skb->csum = csum_unfold(first_desc->csum);
602 }
603
604 /* parse flags & pass relevant info up */
605 if (likely(feat & NETIF_F_RXHASH) &&
606 gve_needs_rss(first_desc->flags_seq))
607 skb_set_hash(skb, be32_to_cpu(first_desc->rss_hash),
608 gve_rss_type(first_desc->flags_seq));
609
610 *packet_size_bytes = skb->len + (skb->protocol ? ETH_HLEN : 0);
611 *work_done = work_cnt;
612 skb_record_rx_queue(skb, rx->q_num);
613 if (skb_is_nonlinear(skb))
614 napi_gro_frags(napi);
615 else
616 napi_gro_receive(napi, skb);
617
618 gve_rx_ctx_clear(ctx);
619 return true;
620
621 skb_alloc_fail:
622 if (napi->skb)
623 napi_free_frags(napi);
624 *packet_size_bytes = 0;
625 *work_done = ctx->expected_frag_cnt;
626 while (ctx->curr_frag_cnt < ctx->expected_frag_cnt) {
627 rx->cnt++;
628 ctx->curr_frag_cnt++;
629 }
630 gve_rx_ctx_clear(ctx);
631 return false;
632 }
633
gve_rx_work_pending(struct gve_rx_ring * rx)634 bool gve_rx_work_pending(struct gve_rx_ring *rx)
635 {
636 struct gve_rx_desc *desc;
637 __be16 flags_seq;
638 u32 next_idx;
639
640 next_idx = rx->cnt & rx->mask;
641 desc = rx->desc.desc_ring + next_idx;
642
643 flags_seq = desc->flags_seq;
644
645 return (GVE_SEQNO(flags_seq) == rx->desc.seqno);
646 }
647
gve_rx_refill_buffers(struct gve_priv * priv,struct gve_rx_ring * rx)648 static bool gve_rx_refill_buffers(struct gve_priv *priv, struct gve_rx_ring *rx)
649 {
650 int refill_target = rx->mask + 1;
651 u32 fill_cnt = rx->fill_cnt;
652
653 while (fill_cnt - rx->cnt < refill_target) {
654 struct gve_rx_slot_page_info *page_info;
655 u32 idx = fill_cnt & rx->mask;
656
657 page_info = &rx->data.page_info[idx];
658 if (page_info->can_flip) {
659 /* The other half of the page is free because it was
660 * free when we processed the descriptor. Flip to it.
661 */
662 union gve_rx_data_slot *data_slot =
663 &rx->data.data_ring[idx];
664
665 gve_rx_flip_buff(page_info, &data_slot->addr);
666 page_info->can_flip = 0;
667 } else {
668 /* It is possible that the networking stack has already
669 * finished processing all outstanding packets in the buffer
670 * and it can be reused.
671 * Flipping is unnecessary here - if the networking stack still
672 * owns half the page it is impossible to tell which half. Either
673 * the whole page is free or it needs to be replaced.
674 */
675 int recycle = gve_rx_can_recycle_buffer(page_info);
676
677 if (recycle < 0) {
678 if (!rx->data.raw_addressing)
679 gve_schedule_reset(priv);
680 return false;
681 }
682 if (!recycle) {
683 /* We can't reuse the buffer - alloc a new one*/
684 union gve_rx_data_slot *data_slot =
685 &rx->data.data_ring[idx];
686 struct device *dev = &priv->pdev->dev;
687 gve_rx_free_buffer(dev, page_info, data_slot);
688 page_info->page = NULL;
689 if (gve_rx_alloc_buffer(priv, dev, page_info,
690 data_slot)) {
691 u64_stats_update_begin(&rx->statss);
692 rx->rx_buf_alloc_fail++;
693 u64_stats_update_end(&rx->statss);
694 break;
695 }
696 }
697 }
698 fill_cnt++;
699 }
700 rx->fill_cnt = fill_cnt;
701 return true;
702 }
703
gve_clean_rx_done(struct gve_rx_ring * rx,int budget,netdev_features_t feat)704 static int gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
705 netdev_features_t feat)
706 {
707 u32 work_done = 0, total_packet_cnt = 0, ok_packet_cnt = 0;
708 struct gve_priv *priv = rx->gve;
709 u32 idx = rx->cnt & rx->mask;
710 struct gve_rx_desc *desc;
711 u64 bytes = 0;
712
713 desc = &rx->desc.desc_ring[idx];
714 while ((GVE_SEQNO(desc->flags_seq) == rx->desc.seqno) &&
715 work_done < budget) {
716 u64 packet_size_bytes = 0;
717 u32 work_cnt = 0;
718 bool dropped;
719
720 netif_info(priv, rx_status, priv->dev,
721 "[%d] idx=%d desc=%p desc->flags_seq=0x%x\n",
722 rx->q_num, idx, desc, desc->flags_seq);
723 netif_info(priv, rx_status, priv->dev,
724 "[%d] seqno=%d rx->desc.seqno=%d\n",
725 rx->q_num, GVE_SEQNO(desc->flags_seq),
726 rx->desc.seqno);
727
728 dropped = !gve_rx(rx, feat, &packet_size_bytes, &work_cnt);
729 if (!dropped) {
730 bytes += packet_size_bytes;
731 ok_packet_cnt++;
732 }
733 total_packet_cnt++;
734 idx = rx->cnt & rx->mask;
735 desc = &rx->desc.desc_ring[idx];
736 work_done += work_cnt;
737 }
738
739 if (!work_done && rx->fill_cnt - rx->cnt > rx->db_threshold)
740 return 0;
741
742 if (work_done) {
743 u64_stats_update_begin(&rx->statss);
744 rx->rpackets += ok_packet_cnt;
745 rx->rbytes += bytes;
746 u64_stats_update_end(&rx->statss);
747 }
748
749 /* restock ring slots */
750 if (!rx->data.raw_addressing) {
751 /* In QPL mode buffs are refilled as the desc are processed */
752 rx->fill_cnt += work_done;
753 } else if (rx->fill_cnt - rx->cnt <= rx->db_threshold) {
754 /* In raw addressing mode buffs are only refilled if the avail
755 * falls below a threshold.
756 */
757 if (!gve_rx_refill_buffers(priv, rx))
758 return 0;
759
760 /* If we were not able to completely refill buffers, we'll want
761 * to schedule this queue for work again to refill buffers.
762 */
763 if (rx->fill_cnt - rx->cnt <= rx->db_threshold) {
764 gve_rx_write_doorbell(priv, rx);
765 return budget;
766 }
767 }
768
769 gve_rx_write_doorbell(priv, rx);
770 return total_packet_cnt;
771 }
772
gve_rx_poll(struct gve_notify_block * block,int budget)773 int gve_rx_poll(struct gve_notify_block *block, int budget)
774 {
775 struct gve_rx_ring *rx = block->rx;
776 netdev_features_t feat;
777 int work_done = 0;
778
779 feat = block->napi.dev->features;
780
781 /* If budget is 0, do all the work */
782 if (budget == 0)
783 budget = INT_MAX;
784
785 if (budget > 0)
786 work_done = gve_clean_rx_done(rx, budget, feat);
787
788 return work_done;
789 }
790