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 #include <linux/filter.h>
12 #include <net/xdp.h>
13 #include <net/xdp_sock_drv.h>
14
gve_rx_free_buffer(struct device * dev,struct gve_rx_slot_page_info * page_info,union gve_rx_data_slot * data_slot)15 static void gve_rx_free_buffer(struct device *dev,
16 struct gve_rx_slot_page_info *page_info,
17 union gve_rx_data_slot *data_slot)
18 {
19 dma_addr_t dma = (dma_addr_t)(be64_to_cpu(data_slot->addr) &
20 GVE_DATA_SLOT_ADDR_PAGE_MASK);
21
22 page_ref_sub(page_info->page, page_info->pagecnt_bias - 1);
23 gve_free_page(dev, page_info->page, dma, DMA_FROM_DEVICE);
24 }
25
gve_rx_unfill_pages(struct gve_priv * priv,struct gve_rx_ring * rx)26 static void gve_rx_unfill_pages(struct gve_priv *priv, struct gve_rx_ring *rx)
27 {
28 u32 slots = rx->mask + 1;
29 int i;
30
31 if (rx->data.raw_addressing) {
32 for (i = 0; i < slots; i++)
33 gve_rx_free_buffer(&priv->pdev->dev, &rx->data.page_info[i],
34 &rx->data.data_ring[i]);
35 } else {
36 for (i = 0; i < slots; i++)
37 page_ref_sub(rx->data.page_info[i].page,
38 rx->data.page_info[i].pagecnt_bias - 1);
39 gve_unassign_qpl(priv, rx->data.qpl->id);
40 rx->data.qpl = NULL;
41
42 for (i = 0; i < rx->qpl_copy_pool_mask + 1; i++) {
43 page_ref_sub(rx->qpl_copy_pool[i].page,
44 rx->qpl_copy_pool[i].pagecnt_bias - 1);
45 put_page(rx->qpl_copy_pool[i].page);
46 }
47 }
48 kvfree(rx->data.page_info);
49 rx->data.page_info = NULL;
50 }
51
gve_rx_free_ring(struct gve_priv * priv,int idx)52 static void gve_rx_free_ring(struct gve_priv *priv, int idx)
53 {
54 struct gve_rx_ring *rx = &priv->rx[idx];
55 struct device *dev = &priv->pdev->dev;
56 u32 slots = rx->mask + 1;
57 size_t bytes;
58
59 gve_rx_remove_from_block(priv, idx);
60
61 bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
62 dma_free_coherent(dev, bytes, rx->desc.desc_ring, rx->desc.bus);
63 rx->desc.desc_ring = NULL;
64
65 dma_free_coherent(dev, sizeof(*rx->q_resources),
66 rx->q_resources, rx->q_resources_bus);
67 rx->q_resources = NULL;
68
69 gve_rx_unfill_pages(priv, rx);
70
71 bytes = sizeof(*rx->data.data_ring) * slots;
72 dma_free_coherent(dev, bytes, rx->data.data_ring,
73 rx->data.data_bus);
74 rx->data.data_ring = NULL;
75
76 kvfree(rx->qpl_copy_pool);
77 rx->qpl_copy_pool = NULL;
78
79 netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
80 }
81
gve_setup_rx_buffer(struct gve_rx_slot_page_info * page_info,dma_addr_t addr,struct page * page,__be64 * slot_addr)82 static void gve_setup_rx_buffer(struct gve_rx_slot_page_info *page_info,
83 dma_addr_t addr, struct page *page, __be64 *slot_addr)
84 {
85 page_info->page = page;
86 page_info->page_offset = 0;
87 page_info->page_address = page_address(page);
88 *slot_addr = cpu_to_be64(addr);
89 /* The page already has 1 ref */
90 page_ref_add(page, INT_MAX - 1);
91 page_info->pagecnt_bias = INT_MAX;
92 }
93
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)94 static int gve_rx_alloc_buffer(struct gve_priv *priv, struct device *dev,
95 struct gve_rx_slot_page_info *page_info,
96 union gve_rx_data_slot *data_slot)
97 {
98 struct page *page;
99 dma_addr_t dma;
100 int err;
101
102 err = gve_alloc_page(priv, dev, &page, &dma, DMA_FROM_DEVICE,
103 GFP_ATOMIC);
104 if (err)
105 return err;
106
107 gve_setup_rx_buffer(page_info, dma, page, &data_slot->addr);
108 return 0;
109 }
110
gve_prefill_rx_pages(struct gve_rx_ring * rx)111 static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
112 {
113 struct gve_priv *priv = rx->gve;
114 u32 slots;
115 int err;
116 int i;
117 int j;
118
119 /* Allocate one page per Rx queue slot. Each page is split into two
120 * packet buffers, when possible we "page flip" between the two.
121 */
122 slots = rx->mask + 1;
123
124 rx->data.page_info = kvzalloc(slots *
125 sizeof(*rx->data.page_info), GFP_KERNEL);
126 if (!rx->data.page_info)
127 return -ENOMEM;
128
129 if (!rx->data.raw_addressing) {
130 rx->data.qpl = gve_assign_rx_qpl(priv, rx->q_num);
131 if (!rx->data.qpl) {
132 kvfree(rx->data.page_info);
133 rx->data.page_info = NULL;
134 return -ENOMEM;
135 }
136 }
137 for (i = 0; i < slots; i++) {
138 if (!rx->data.raw_addressing) {
139 struct page *page = rx->data.qpl->pages[i];
140 dma_addr_t addr = i * PAGE_SIZE;
141
142 gve_setup_rx_buffer(&rx->data.page_info[i], addr, page,
143 &rx->data.data_ring[i].qpl_offset);
144 continue;
145 }
146 err = gve_rx_alloc_buffer(priv, &priv->pdev->dev, &rx->data.page_info[i],
147 &rx->data.data_ring[i]);
148 if (err)
149 goto alloc_err_rda;
150 }
151
152 if (!rx->data.raw_addressing) {
153 for (j = 0; j < rx->qpl_copy_pool_mask + 1; j++) {
154 struct page *page = alloc_page(GFP_KERNEL);
155
156 if (!page) {
157 err = -ENOMEM;
158 goto alloc_err_qpl;
159 }
160
161 rx->qpl_copy_pool[j].page = page;
162 rx->qpl_copy_pool[j].page_offset = 0;
163 rx->qpl_copy_pool[j].page_address = page_address(page);
164
165 /* The page already has 1 ref. */
166 page_ref_add(page, INT_MAX - 1);
167 rx->qpl_copy_pool[j].pagecnt_bias = INT_MAX;
168 }
169 }
170
171 return slots;
172
173 alloc_err_qpl:
174 /* Fully free the copy pool pages. */
175 while (j--) {
176 page_ref_sub(rx->qpl_copy_pool[j].page,
177 rx->qpl_copy_pool[j].pagecnt_bias - 1);
178 put_page(rx->qpl_copy_pool[j].page);
179 }
180
181 /* Do not fully free QPL pages - only remove the bias added in this
182 * function with gve_setup_rx_buffer.
183 */
184 while (i--)
185 page_ref_sub(rx->data.page_info[i].page,
186 rx->data.page_info[i].pagecnt_bias - 1);
187
188 gve_unassign_qpl(priv, rx->data.qpl->id);
189 rx->data.qpl = NULL;
190
191 return err;
192
193 alloc_err_rda:
194 while (i--)
195 gve_rx_free_buffer(&priv->pdev->dev,
196 &rx->data.page_info[i],
197 &rx->data.data_ring[i]);
198 return err;
199 }
200
gve_rx_ctx_clear(struct gve_rx_ctx * ctx)201 static void gve_rx_ctx_clear(struct gve_rx_ctx *ctx)
202 {
203 ctx->skb_head = NULL;
204 ctx->skb_tail = NULL;
205 ctx->total_size = 0;
206 ctx->frag_cnt = 0;
207 ctx->drop_pkt = false;
208 }
209
gve_rx_alloc_ring(struct gve_priv * priv,int idx)210 static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
211 {
212 struct gve_rx_ring *rx = &priv->rx[idx];
213 struct device *hdev = &priv->pdev->dev;
214 u32 slots, npages;
215 int filled_pages;
216 size_t bytes;
217 int err;
218
219 netif_dbg(priv, drv, priv->dev, "allocating rx ring\n");
220 /* Make sure everything is zeroed to start with */
221 memset(rx, 0, sizeof(*rx));
222
223 rx->gve = priv;
224 rx->q_num = idx;
225
226 slots = priv->rx_data_slot_cnt;
227 rx->mask = slots - 1;
228 rx->data.raw_addressing = priv->queue_format == GVE_GQI_RDA_FORMAT;
229
230 /* alloc rx data ring */
231 bytes = sizeof(*rx->data.data_ring) * slots;
232 rx->data.data_ring = dma_alloc_coherent(hdev, bytes,
233 &rx->data.data_bus,
234 GFP_KERNEL);
235 if (!rx->data.data_ring)
236 return -ENOMEM;
237
238 rx->qpl_copy_pool_mask = min_t(u32, U32_MAX, slots * 2) - 1;
239 rx->qpl_copy_pool_head = 0;
240 rx->qpl_copy_pool = kvcalloc(rx->qpl_copy_pool_mask + 1,
241 sizeof(rx->qpl_copy_pool[0]),
242 GFP_KERNEL);
243
244 if (!rx->qpl_copy_pool) {
245 err = -ENOMEM;
246 goto abort_with_slots;
247 }
248
249 filled_pages = gve_prefill_rx_pages(rx);
250 if (filled_pages < 0) {
251 err = -ENOMEM;
252 goto abort_with_copy_pool;
253 }
254 rx->fill_cnt = filled_pages;
255 /* Ensure data ring slots (packet buffers) are visible. */
256 dma_wmb();
257
258 /* Alloc gve_queue_resources */
259 rx->q_resources =
260 dma_alloc_coherent(hdev,
261 sizeof(*rx->q_resources),
262 &rx->q_resources_bus,
263 GFP_KERNEL);
264 if (!rx->q_resources) {
265 err = -ENOMEM;
266 goto abort_filled;
267 }
268 netif_dbg(priv, drv, priv->dev, "rx[%d]->data.data_bus=%lx\n", idx,
269 (unsigned long)rx->data.data_bus);
270
271 /* alloc rx desc ring */
272 bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
273 npages = bytes / PAGE_SIZE;
274 if (npages * PAGE_SIZE != bytes) {
275 err = -EIO;
276 goto abort_with_q_resources;
277 }
278
279 rx->desc.desc_ring = dma_alloc_coherent(hdev, bytes, &rx->desc.bus,
280 GFP_KERNEL);
281 if (!rx->desc.desc_ring) {
282 err = -ENOMEM;
283 goto abort_with_q_resources;
284 }
285 rx->cnt = 0;
286 rx->db_threshold = priv->rx_desc_cnt / 2;
287 rx->desc.seqno = 1;
288
289 /* Allocating half-page buffers allows page-flipping which is faster
290 * than copying or allocating new pages.
291 */
292 rx->packet_buffer_size = PAGE_SIZE / 2;
293 gve_rx_ctx_clear(&rx->ctx);
294 gve_rx_add_to_block(priv, idx);
295
296 return 0;
297
298 abort_with_q_resources:
299 dma_free_coherent(hdev, sizeof(*rx->q_resources),
300 rx->q_resources, rx->q_resources_bus);
301 rx->q_resources = NULL;
302 abort_filled:
303 gve_rx_unfill_pages(priv, rx);
304 abort_with_copy_pool:
305 kvfree(rx->qpl_copy_pool);
306 rx->qpl_copy_pool = NULL;
307 abort_with_slots:
308 bytes = sizeof(*rx->data.data_ring) * slots;
309 dma_free_coherent(hdev, bytes, rx->data.data_ring, rx->data.data_bus);
310 rx->data.data_ring = NULL;
311
312 return err;
313 }
314
gve_rx_alloc_rings(struct gve_priv * priv)315 int gve_rx_alloc_rings(struct gve_priv *priv)
316 {
317 int err = 0;
318 int i;
319
320 for (i = 0; i < priv->rx_cfg.num_queues; i++) {
321 err = gve_rx_alloc_ring(priv, i);
322 if (err) {
323 netif_err(priv, drv, priv->dev,
324 "Failed to alloc rx ring=%d: err=%d\n",
325 i, err);
326 break;
327 }
328 }
329 /* Unallocate if there was an error */
330 if (err) {
331 int j;
332
333 for (j = 0; j < i; j++)
334 gve_rx_free_ring(priv, j);
335 }
336 return err;
337 }
338
gve_rx_free_rings_gqi(struct gve_priv * priv)339 void gve_rx_free_rings_gqi(struct gve_priv *priv)
340 {
341 int i;
342
343 for (i = 0; i < priv->rx_cfg.num_queues; i++)
344 gve_rx_free_ring(priv, i);
345 }
346
gve_rx_write_doorbell(struct gve_priv * priv,struct gve_rx_ring * rx)347 void gve_rx_write_doorbell(struct gve_priv *priv, struct gve_rx_ring *rx)
348 {
349 u32 db_idx = be32_to_cpu(rx->q_resources->db_index);
350
351 iowrite32be(rx->fill_cnt, &priv->db_bar2[db_idx]);
352 }
353
gve_rss_type(__be16 pkt_flags)354 static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
355 {
356 if (likely(pkt_flags & (GVE_RXF_TCP | GVE_RXF_UDP)))
357 return PKT_HASH_TYPE_L4;
358 if (pkt_flags & (GVE_RXF_IPV4 | GVE_RXF_IPV6))
359 return PKT_HASH_TYPE_L3;
360 return PKT_HASH_TYPE_L2;
361 }
362
gve_rx_add_frags(struct napi_struct * napi,struct gve_rx_slot_page_info * page_info,unsigned int truesize,u16 len,struct gve_rx_ctx * ctx)363 static struct sk_buff *gve_rx_add_frags(struct napi_struct *napi,
364 struct gve_rx_slot_page_info *page_info,
365 unsigned int truesize, u16 len,
366 struct gve_rx_ctx *ctx)
367 {
368 u32 offset = page_info->page_offset + page_info->pad;
369 struct sk_buff *skb = ctx->skb_tail;
370 int num_frags = 0;
371
372 if (!skb) {
373 skb = napi_get_frags(napi);
374 if (unlikely(!skb))
375 return NULL;
376
377 ctx->skb_head = skb;
378 ctx->skb_tail = skb;
379 } else {
380 num_frags = skb_shinfo(ctx->skb_tail)->nr_frags;
381 if (num_frags == MAX_SKB_FRAGS) {
382 skb = napi_alloc_skb(napi, 0);
383 if (!skb)
384 return NULL;
385
386 // We will never chain more than two SKBs: 2 * 16 * 2k > 64k
387 // which is why we do not need to chain by using skb->next
388 skb_shinfo(ctx->skb_tail)->frag_list = skb;
389
390 ctx->skb_tail = skb;
391 num_frags = 0;
392 }
393 }
394
395 if (skb != ctx->skb_head) {
396 ctx->skb_head->len += len;
397 ctx->skb_head->data_len += len;
398 ctx->skb_head->truesize += truesize;
399 }
400 skb_add_rx_frag(skb, num_frags, page_info->page,
401 offset, len, truesize);
402
403 return ctx->skb_head;
404 }
405
gve_rx_flip_buff(struct gve_rx_slot_page_info * page_info,__be64 * slot_addr)406 static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info, __be64 *slot_addr)
407 {
408 const __be64 offset = cpu_to_be64(PAGE_SIZE / 2);
409
410 /* "flip" to other packet buffer on this page */
411 page_info->page_offset ^= PAGE_SIZE / 2;
412 *(slot_addr) ^= offset;
413 }
414
gve_rx_can_recycle_buffer(struct gve_rx_slot_page_info * page_info)415 static int gve_rx_can_recycle_buffer(struct gve_rx_slot_page_info *page_info)
416 {
417 int pagecount = page_count(page_info->page);
418
419 /* This page is not being used by any SKBs - reuse */
420 if (pagecount == page_info->pagecnt_bias)
421 return 1;
422 /* This page is still being used by an SKB - we can't reuse */
423 else if (pagecount > page_info->pagecnt_bias)
424 return 0;
425 WARN(pagecount < page_info->pagecnt_bias,
426 "Pagecount should never be less than the bias.");
427 return -1;
428 }
429
430 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)431 gve_rx_raw_addressing(struct device *dev, struct net_device *netdev,
432 struct gve_rx_slot_page_info *page_info, u16 len,
433 struct napi_struct *napi,
434 union gve_rx_data_slot *data_slot,
435 u16 packet_buffer_size, struct gve_rx_ctx *ctx)
436 {
437 struct sk_buff *skb = gve_rx_add_frags(napi, page_info, packet_buffer_size, len, ctx);
438
439 if (!skb)
440 return NULL;
441
442 /* Optimistically stop the kernel from freeing the page.
443 * We will check again in refill to determine if we need to alloc a
444 * new page.
445 */
446 gve_dec_pagecnt_bias(page_info);
447
448 return skb;
449 }
450
gve_rx_copy_to_pool(struct gve_rx_ring * rx,struct gve_rx_slot_page_info * page_info,u16 len,struct napi_struct * napi)451 static struct sk_buff *gve_rx_copy_to_pool(struct gve_rx_ring *rx,
452 struct gve_rx_slot_page_info *page_info,
453 u16 len, struct napi_struct *napi)
454 {
455 u32 pool_idx = rx->qpl_copy_pool_head & rx->qpl_copy_pool_mask;
456 void *src = page_info->page_address + page_info->page_offset;
457 struct gve_rx_slot_page_info *copy_page_info;
458 struct gve_rx_ctx *ctx = &rx->ctx;
459 bool alloc_page = false;
460 struct sk_buff *skb;
461 void *dst;
462
463 copy_page_info = &rx->qpl_copy_pool[pool_idx];
464 if (!copy_page_info->can_flip) {
465 int recycle = gve_rx_can_recycle_buffer(copy_page_info);
466
467 if (unlikely(recycle < 0)) {
468 gve_schedule_reset(rx->gve);
469 return NULL;
470 }
471 alloc_page = !recycle;
472 }
473
474 if (alloc_page) {
475 struct gve_rx_slot_page_info alloc_page_info;
476 struct page *page;
477
478 /* The least recently used page turned out to be
479 * still in use by the kernel. Ignoring it and moving
480 * on alleviates head-of-line blocking.
481 */
482 rx->qpl_copy_pool_head++;
483
484 page = alloc_page(GFP_ATOMIC);
485 if (!page)
486 return NULL;
487
488 alloc_page_info.page = page;
489 alloc_page_info.page_offset = 0;
490 alloc_page_info.page_address = page_address(page);
491 alloc_page_info.pad = page_info->pad;
492
493 memcpy(alloc_page_info.page_address, src, page_info->pad + len);
494 skb = gve_rx_add_frags(napi, &alloc_page_info,
495 PAGE_SIZE,
496 len, ctx);
497
498 u64_stats_update_begin(&rx->statss);
499 rx->rx_frag_copy_cnt++;
500 rx->rx_frag_alloc_cnt++;
501 u64_stats_update_end(&rx->statss);
502
503 return skb;
504 }
505
506 dst = copy_page_info->page_address + copy_page_info->page_offset;
507 memcpy(dst, src, page_info->pad + len);
508 copy_page_info->pad = page_info->pad;
509
510 skb = gve_rx_add_frags(napi, copy_page_info,
511 rx->packet_buffer_size, len, ctx);
512 if (unlikely(!skb))
513 return NULL;
514
515 gve_dec_pagecnt_bias(copy_page_info);
516 copy_page_info->page_offset += rx->packet_buffer_size;
517 copy_page_info->page_offset &= (PAGE_SIZE - 1);
518
519 if (copy_page_info->can_flip) {
520 /* We have used both halves of this copy page, it
521 * is time for it to go to the back of the queue.
522 */
523 copy_page_info->can_flip = false;
524 rx->qpl_copy_pool_head++;
525 prefetch(rx->qpl_copy_pool[rx->qpl_copy_pool_head & rx->qpl_copy_pool_mask].page);
526 } else {
527 copy_page_info->can_flip = true;
528 }
529
530 u64_stats_update_begin(&rx->statss);
531 rx->rx_frag_copy_cnt++;
532 u64_stats_update_end(&rx->statss);
533
534 return skb;
535 }
536
537 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)538 gve_rx_qpl(struct device *dev, struct net_device *netdev,
539 struct gve_rx_ring *rx, struct gve_rx_slot_page_info *page_info,
540 u16 len, struct napi_struct *napi,
541 union gve_rx_data_slot *data_slot)
542 {
543 struct gve_rx_ctx *ctx = &rx->ctx;
544 struct sk_buff *skb;
545
546 /* if raw_addressing mode is not enabled gvnic can only receive into
547 * registered segments. If the buffer can't be recycled, our only
548 * choice is to copy the data out of it so that we can return it to the
549 * device.
550 */
551 if (page_info->can_flip) {
552 skb = gve_rx_add_frags(napi, page_info, rx->packet_buffer_size, len, ctx);
553 /* No point in recycling if we didn't get the skb */
554 if (skb) {
555 /* Make sure that the page isn't freed. */
556 gve_dec_pagecnt_bias(page_info);
557 gve_rx_flip_buff(page_info, &data_slot->qpl_offset);
558 }
559 } else {
560 skb = gve_rx_copy_to_pool(rx, page_info, len, napi);
561 }
562 return skb;
563 }
564
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,bool is_only_frag)565 static struct sk_buff *gve_rx_skb(struct gve_priv *priv, struct gve_rx_ring *rx,
566 struct gve_rx_slot_page_info *page_info, struct napi_struct *napi,
567 u16 len, union gve_rx_data_slot *data_slot,
568 bool is_only_frag)
569 {
570 struct net_device *netdev = priv->dev;
571 struct gve_rx_ctx *ctx = &rx->ctx;
572 struct sk_buff *skb = NULL;
573
574 if (len <= priv->rx_copybreak && is_only_frag) {
575 /* Just copy small packets */
576 skb = gve_rx_copy(netdev, napi, page_info, len);
577 if (skb) {
578 u64_stats_update_begin(&rx->statss);
579 rx->rx_copied_pkt++;
580 rx->rx_frag_copy_cnt++;
581 rx->rx_copybreak_pkt++;
582 u64_stats_update_end(&rx->statss);
583 }
584 } else {
585 int recycle = gve_rx_can_recycle_buffer(page_info);
586
587 if (unlikely(recycle < 0)) {
588 gve_schedule_reset(priv);
589 return NULL;
590 }
591 page_info->can_flip = recycle;
592 if (page_info->can_flip) {
593 u64_stats_update_begin(&rx->statss);
594 rx->rx_frag_flip_cnt++;
595 u64_stats_update_end(&rx->statss);
596 }
597
598 if (rx->data.raw_addressing) {
599 skb = gve_rx_raw_addressing(&priv->pdev->dev, netdev,
600 page_info, len, napi,
601 data_slot,
602 rx->packet_buffer_size, ctx);
603 } else {
604 skb = gve_rx_qpl(&priv->pdev->dev, netdev, rx,
605 page_info, len, napi, data_slot);
606 }
607 }
608 return skb;
609 }
610
gve_xsk_pool_redirect(struct net_device * dev,struct gve_rx_ring * rx,void * data,int len,struct bpf_prog * xdp_prog)611 static int gve_xsk_pool_redirect(struct net_device *dev,
612 struct gve_rx_ring *rx,
613 void *data, int len,
614 struct bpf_prog *xdp_prog)
615 {
616 struct xdp_buff *xdp;
617 int err;
618
619 if (rx->xsk_pool->frame_len < len)
620 return -E2BIG;
621 xdp = xsk_buff_alloc(rx->xsk_pool);
622 if (!xdp) {
623 u64_stats_update_begin(&rx->statss);
624 rx->xdp_alloc_fails++;
625 u64_stats_update_end(&rx->statss);
626 return -ENOMEM;
627 }
628 xdp->data_end = xdp->data + len;
629 memcpy(xdp->data, data, len);
630 err = xdp_do_redirect(dev, xdp, xdp_prog);
631 if (err)
632 xsk_buff_free(xdp);
633 return err;
634 }
635
gve_xdp_redirect(struct net_device * dev,struct gve_rx_ring * rx,struct xdp_buff * orig,struct bpf_prog * xdp_prog)636 static int gve_xdp_redirect(struct net_device *dev, struct gve_rx_ring *rx,
637 struct xdp_buff *orig, struct bpf_prog *xdp_prog)
638 {
639 int total_len, len = orig->data_end - orig->data;
640 int headroom = XDP_PACKET_HEADROOM;
641 struct xdp_buff new;
642 void *frame;
643 int err;
644
645 if (rx->xsk_pool)
646 return gve_xsk_pool_redirect(dev, rx, orig->data,
647 len, xdp_prog);
648
649 total_len = headroom + SKB_DATA_ALIGN(len) +
650 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
651 frame = page_frag_alloc(&rx->page_cache, total_len, GFP_ATOMIC);
652 if (!frame) {
653 u64_stats_update_begin(&rx->statss);
654 rx->xdp_alloc_fails++;
655 u64_stats_update_end(&rx->statss);
656 return -ENOMEM;
657 }
658 xdp_init_buff(&new, total_len, &rx->xdp_rxq);
659 xdp_prepare_buff(&new, frame, headroom, len, false);
660 memcpy(new.data, orig->data, len);
661
662 err = xdp_do_redirect(dev, &new, xdp_prog);
663 if (err)
664 page_frag_free(frame);
665
666 return err;
667 }
668
gve_xdp_done(struct gve_priv * priv,struct gve_rx_ring * rx,struct xdp_buff * xdp,struct bpf_prog * xprog,int xdp_act)669 static void gve_xdp_done(struct gve_priv *priv, struct gve_rx_ring *rx,
670 struct xdp_buff *xdp, struct bpf_prog *xprog,
671 int xdp_act)
672 {
673 struct gve_tx_ring *tx;
674 int tx_qid;
675 int err;
676
677 switch (xdp_act) {
678 case XDP_ABORTED:
679 case XDP_DROP:
680 default:
681 break;
682 case XDP_TX:
683 tx_qid = gve_xdp_tx_queue_id(priv, rx->q_num);
684 tx = &priv->tx[tx_qid];
685 spin_lock(&tx->xdp_lock);
686 err = gve_xdp_xmit_one(priv, tx, xdp->data,
687 xdp->data_end - xdp->data, NULL);
688 spin_unlock(&tx->xdp_lock);
689
690 if (unlikely(err)) {
691 u64_stats_update_begin(&rx->statss);
692 rx->xdp_tx_errors++;
693 u64_stats_update_end(&rx->statss);
694 }
695 break;
696 case XDP_REDIRECT:
697 err = gve_xdp_redirect(priv->dev, rx, xdp, xprog);
698
699 if (unlikely(err)) {
700 u64_stats_update_begin(&rx->statss);
701 rx->xdp_redirect_errors++;
702 u64_stats_update_end(&rx->statss);
703 }
704 break;
705 }
706 u64_stats_update_begin(&rx->statss);
707 if ((u32)xdp_act < GVE_XDP_ACTIONS)
708 rx->xdp_actions[xdp_act]++;
709 u64_stats_update_end(&rx->statss);
710 }
711
712 #define GVE_PKTCONT_BIT_IS_SET(x) (GVE_RXF_PKT_CONT & (x))
gve_rx(struct gve_rx_ring * rx,netdev_features_t feat,struct gve_rx_desc * desc,u32 idx,struct gve_rx_cnts * cnts)713 static void gve_rx(struct gve_rx_ring *rx, netdev_features_t feat,
714 struct gve_rx_desc *desc, u32 idx,
715 struct gve_rx_cnts *cnts)
716 {
717 bool is_last_frag = !GVE_PKTCONT_BIT_IS_SET(desc->flags_seq);
718 struct gve_rx_slot_page_info *page_info;
719 u16 frag_size = be16_to_cpu(desc->len);
720 struct gve_rx_ctx *ctx = &rx->ctx;
721 union gve_rx_data_slot *data_slot;
722 struct gve_priv *priv = rx->gve;
723 struct sk_buff *skb = NULL;
724 struct bpf_prog *xprog;
725 struct xdp_buff xdp;
726 dma_addr_t page_bus;
727 void *va;
728
729 u16 len = frag_size;
730 struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
731 bool is_first_frag = ctx->frag_cnt == 0;
732
733 bool is_only_frag = is_first_frag && is_last_frag;
734
735 if (unlikely(ctx->drop_pkt))
736 goto finish_frag;
737
738 if (desc->flags_seq & GVE_RXF_ERR) {
739 ctx->drop_pkt = true;
740 cnts->desc_err_pkt_cnt++;
741 napi_free_frags(napi);
742 goto finish_frag;
743 }
744
745 if (unlikely(frag_size > rx->packet_buffer_size)) {
746 netdev_warn(priv->dev, "Unexpected frag size %d, can't exceed %d, scheduling reset",
747 frag_size, rx->packet_buffer_size);
748 ctx->drop_pkt = true;
749 napi_free_frags(napi);
750 gve_schedule_reset(rx->gve);
751 goto finish_frag;
752 }
753
754 /* Prefetch two packet buffers ahead, we will need it soon. */
755 page_info = &rx->data.page_info[(idx + 2) & rx->mask];
756 va = page_info->page_address + page_info->page_offset;
757 prefetch(page_info->page); /* Kernel page struct. */
758 prefetch(va); /* Packet header. */
759 prefetch(va + 64); /* Next cacheline too. */
760
761 page_info = &rx->data.page_info[idx];
762 data_slot = &rx->data.data_ring[idx];
763 page_bus = (rx->data.raw_addressing) ?
764 be64_to_cpu(data_slot->addr) - page_info->page_offset :
765 rx->data.qpl->page_buses[idx];
766 dma_sync_single_for_cpu(&priv->pdev->dev, page_bus,
767 PAGE_SIZE, DMA_FROM_DEVICE);
768 page_info->pad = is_first_frag ? GVE_RX_PAD : 0;
769 len -= page_info->pad;
770 frag_size -= page_info->pad;
771
772 xprog = READ_ONCE(priv->xdp_prog);
773 if (xprog && is_only_frag) {
774 void *old_data;
775 int xdp_act;
776
777 xdp_init_buff(&xdp, rx->packet_buffer_size, &rx->xdp_rxq);
778 xdp_prepare_buff(&xdp, page_info->page_address +
779 page_info->page_offset, GVE_RX_PAD,
780 len, false);
781 old_data = xdp.data;
782 xdp_act = bpf_prog_run_xdp(xprog, &xdp);
783 if (xdp_act != XDP_PASS) {
784 gve_xdp_done(priv, rx, &xdp, xprog, xdp_act);
785 ctx->total_size += frag_size;
786 goto finish_ok_pkt;
787 }
788
789 page_info->pad += xdp.data - old_data;
790 len = xdp.data_end - xdp.data;
791
792 u64_stats_update_begin(&rx->statss);
793 rx->xdp_actions[XDP_PASS]++;
794 u64_stats_update_end(&rx->statss);
795 }
796
797 skb = gve_rx_skb(priv, rx, page_info, napi, len,
798 data_slot, is_only_frag);
799 if (!skb) {
800 u64_stats_update_begin(&rx->statss);
801 rx->rx_skb_alloc_fail++;
802 u64_stats_update_end(&rx->statss);
803
804 napi_free_frags(napi);
805 ctx->drop_pkt = true;
806 goto finish_frag;
807 }
808 ctx->total_size += frag_size;
809
810 if (is_first_frag) {
811 if (likely(feat & NETIF_F_RXCSUM)) {
812 /* NIC passes up the partial sum */
813 if (desc->csum)
814 skb->ip_summed = CHECKSUM_COMPLETE;
815 else
816 skb->ip_summed = CHECKSUM_NONE;
817 skb->csum = csum_unfold(desc->csum);
818 }
819
820 /* parse flags & pass relevant info up */
821 if (likely(feat & NETIF_F_RXHASH) &&
822 gve_needs_rss(desc->flags_seq))
823 skb_set_hash(skb, be32_to_cpu(desc->rss_hash),
824 gve_rss_type(desc->flags_seq));
825 }
826
827 if (is_last_frag) {
828 skb_record_rx_queue(skb, rx->q_num);
829 if (skb_is_nonlinear(skb))
830 napi_gro_frags(napi);
831 else
832 napi_gro_receive(napi, skb);
833 goto finish_ok_pkt;
834 }
835
836 goto finish_frag;
837
838 finish_ok_pkt:
839 cnts->ok_pkt_bytes += ctx->total_size;
840 cnts->ok_pkt_cnt++;
841 finish_frag:
842 ctx->frag_cnt++;
843 if (is_last_frag) {
844 cnts->total_pkt_cnt++;
845 cnts->cont_pkt_cnt += (ctx->frag_cnt > 1);
846 gve_rx_ctx_clear(ctx);
847 }
848 }
849
gve_rx_work_pending(struct gve_rx_ring * rx)850 bool gve_rx_work_pending(struct gve_rx_ring *rx)
851 {
852 struct gve_rx_desc *desc;
853 __be16 flags_seq;
854 u32 next_idx;
855
856 next_idx = rx->cnt & rx->mask;
857 desc = rx->desc.desc_ring + next_idx;
858
859 flags_seq = desc->flags_seq;
860
861 return (GVE_SEQNO(flags_seq) == rx->desc.seqno);
862 }
863
gve_rx_refill_buffers(struct gve_priv * priv,struct gve_rx_ring * rx)864 static bool gve_rx_refill_buffers(struct gve_priv *priv, struct gve_rx_ring *rx)
865 {
866 int refill_target = rx->mask + 1;
867 u32 fill_cnt = rx->fill_cnt;
868
869 while (fill_cnt - rx->cnt < refill_target) {
870 struct gve_rx_slot_page_info *page_info;
871 u32 idx = fill_cnt & rx->mask;
872
873 page_info = &rx->data.page_info[idx];
874 if (page_info->can_flip) {
875 /* The other half of the page is free because it was
876 * free when we processed the descriptor. Flip to it.
877 */
878 union gve_rx_data_slot *data_slot =
879 &rx->data.data_ring[idx];
880
881 gve_rx_flip_buff(page_info, &data_slot->addr);
882 page_info->can_flip = 0;
883 } else {
884 /* It is possible that the networking stack has already
885 * finished processing all outstanding packets in the buffer
886 * and it can be reused.
887 * Flipping is unnecessary here - if the networking stack still
888 * owns half the page it is impossible to tell which half. Either
889 * the whole page is free or it needs to be replaced.
890 */
891 int recycle = gve_rx_can_recycle_buffer(page_info);
892
893 if (recycle < 0) {
894 if (!rx->data.raw_addressing)
895 gve_schedule_reset(priv);
896 return false;
897 }
898 if (!recycle) {
899 /* We can't reuse the buffer - alloc a new one*/
900 union gve_rx_data_slot *data_slot =
901 &rx->data.data_ring[idx];
902 struct device *dev = &priv->pdev->dev;
903 gve_rx_free_buffer(dev, page_info, data_slot);
904 page_info->page = NULL;
905 if (gve_rx_alloc_buffer(priv, dev, page_info,
906 data_slot)) {
907 u64_stats_update_begin(&rx->statss);
908 rx->rx_buf_alloc_fail++;
909 u64_stats_update_end(&rx->statss);
910 break;
911 }
912 }
913 }
914 fill_cnt++;
915 }
916 rx->fill_cnt = fill_cnt;
917 return true;
918 }
919
gve_clean_rx_done(struct gve_rx_ring * rx,int budget,netdev_features_t feat)920 static int gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
921 netdev_features_t feat)
922 {
923 u64 xdp_redirects = rx->xdp_actions[XDP_REDIRECT];
924 u64 xdp_txs = rx->xdp_actions[XDP_TX];
925 struct gve_rx_ctx *ctx = &rx->ctx;
926 struct gve_priv *priv = rx->gve;
927 struct gve_rx_cnts cnts = {0};
928 struct gve_rx_desc *next_desc;
929 u32 idx = rx->cnt & rx->mask;
930 u32 work_done = 0;
931
932 struct gve_rx_desc *desc = &rx->desc.desc_ring[idx];
933
934 // Exceed budget only if (and till) the inflight packet is consumed.
935 while ((GVE_SEQNO(desc->flags_seq) == rx->desc.seqno) &&
936 (work_done < budget || ctx->frag_cnt)) {
937 next_desc = &rx->desc.desc_ring[(idx + 1) & rx->mask];
938 prefetch(next_desc);
939
940 gve_rx(rx, feat, desc, idx, &cnts);
941
942 rx->cnt++;
943 idx = rx->cnt & rx->mask;
944 desc = &rx->desc.desc_ring[idx];
945 rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
946 work_done++;
947 }
948
949 // The device will only send whole packets.
950 if (unlikely(ctx->frag_cnt)) {
951 struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
952
953 napi_free_frags(napi);
954 gve_rx_ctx_clear(&rx->ctx);
955 netdev_warn(priv->dev, "Unexpected seq number %d with incomplete packet, expected %d, scheduling reset",
956 GVE_SEQNO(desc->flags_seq), rx->desc.seqno);
957 gve_schedule_reset(rx->gve);
958 }
959
960 if (!work_done && rx->fill_cnt - rx->cnt > rx->db_threshold)
961 return 0;
962
963 if (work_done) {
964 u64_stats_update_begin(&rx->statss);
965 rx->rpackets += cnts.ok_pkt_cnt;
966 rx->rbytes += cnts.ok_pkt_bytes;
967 rx->rx_cont_packet_cnt += cnts.cont_pkt_cnt;
968 rx->rx_desc_err_dropped_pkt += cnts.desc_err_pkt_cnt;
969 u64_stats_update_end(&rx->statss);
970 }
971
972 if (xdp_txs != rx->xdp_actions[XDP_TX])
973 gve_xdp_tx_flush(priv, rx->q_num);
974
975 if (xdp_redirects != rx->xdp_actions[XDP_REDIRECT])
976 xdp_do_flush();
977
978 /* restock ring slots */
979 if (!rx->data.raw_addressing) {
980 /* In QPL mode buffs are refilled as the desc are processed */
981 rx->fill_cnt += work_done;
982 } else if (rx->fill_cnt - rx->cnt <= rx->db_threshold) {
983 /* In raw addressing mode buffs are only refilled if the avail
984 * falls below a threshold.
985 */
986 if (!gve_rx_refill_buffers(priv, rx))
987 return 0;
988
989 /* If we were not able to completely refill buffers, we'll want
990 * to schedule this queue for work again to refill buffers.
991 */
992 if (rx->fill_cnt - rx->cnt <= rx->db_threshold) {
993 gve_rx_write_doorbell(priv, rx);
994 return budget;
995 }
996 }
997
998 gve_rx_write_doorbell(priv, rx);
999 return cnts.total_pkt_cnt;
1000 }
1001
gve_rx_poll(struct gve_notify_block * block,int budget)1002 int gve_rx_poll(struct gve_notify_block *block, int budget)
1003 {
1004 struct gve_rx_ring *rx = block->rx;
1005 netdev_features_t feat;
1006 int work_done = 0;
1007
1008 feat = block->napi.dev->features;
1009
1010 if (budget > 0)
1011 work_done = gve_clean_rx_done(rx, budget, feat);
1012
1013 return work_done;
1014 }
1015