bnxt_xdp.c

  1/* Broadcom NetXtreme-C/E network driver.
  2 *
  3 * Copyright (c) 2016-2017 Broadcom Limited
  4 *
  5 * This program is free software; you can redistribute it and/or modify
  6 * it under the terms of the GNU General Public License as published by
  7 * the Free Software Foundation.
  8 */
  9#include <linux/kernel.h>
 10#include <linux/errno.h>
 11#include <linux/pci.h>
 12#include <linux/netdevice.h>
 13#include <linux/etherdevice.h>
 14#include <linux/if_vlan.h>
 15#include <linux/bpf.h>
 16#include <linux/bpf_trace.h>
 17#include <linux/filter.h>
 18#include <net/netdev_lock.h>
 19#include <net/page_pool/helpers.h>
 20#include <linux/bnxt/hsi.h>
 21#include "bnxt.h"
 22#include "bnxt_xdp.h"
 23
 24DEFINE_STATIC_KEY_FALSE(bnxt_xdp_locking_key);
 25
 26struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
 27				   struct bnxt_tx_ring_info *txr,
 28				   dma_addr_t mapping, u32 len,
 29				   struct xdp_buff *xdp)
 30{
 31	struct skb_shared_info *sinfo;
 32	struct bnxt_sw_tx_bd *tx_buf;
 33	struct tx_bd *txbd;
 34	int num_frags = 0;
 35	u32 flags;
 36	u16 prod;
 37	int i;
 38
 39	if (xdp && xdp_buff_has_frags(xdp)) {
 40		sinfo = xdp_get_shared_info_from_buff(xdp);
 41		num_frags = sinfo->nr_frags;
 42	}
 43
 44	/* fill up the first buffer */
 45	prod = txr->tx_prod;
 46	tx_buf = &txr->tx_buf_ring[RING_TX(bp, prod)];
 47	tx_buf->nr_frags = num_frags;
 48	if (xdp)
 49		tx_buf->page = virt_to_head_page(xdp->data);
 50
 51	txbd = &txr->tx_desc_ring[TX_RING(bp, prod)][TX_IDX(prod)];
 52	flags = (len << TX_BD_LEN_SHIFT) | TX_BD_CNT(num_frags + 1) |
 53		bnxt_lhint_arr[len >> 9];
 54	txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
 55	txbd->tx_bd_opaque = SET_TX_OPAQUE(bp, txr, prod, 1 + num_frags);
 56	txbd->tx_bd_haddr = cpu_to_le64(mapping);
 57
 58	/* now let us fill up the frags into the next buffers */
 59	for (i = 0; i < num_frags ; i++) {
 60		skb_frag_t *frag = &sinfo->frags[i];
 61		struct bnxt_sw_tx_bd *frag_tx_buf;
 62		dma_addr_t frag_mapping;
 63		int frag_len;
 64
 65		prod = NEXT_TX(prod);
 66		WRITE_ONCE(txr->tx_prod, prod);
 67
 68		/* first fill up the first buffer */
 69		frag_tx_buf = &txr->tx_buf_ring[RING_TX(bp, prod)];
 70		frag_tx_buf->page = skb_frag_page(frag);
 71
 72		txbd = &txr->tx_desc_ring[TX_RING(bp, prod)][TX_IDX(prod)];
 73
 74		frag_len = skb_frag_size(frag);
 75		flags = frag_len << TX_BD_LEN_SHIFT;
 76		txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
 77		frag_mapping = page_pool_get_dma_addr(skb_frag_page(frag)) +
 78			       skb_frag_off(frag);
 79		txbd->tx_bd_haddr = cpu_to_le64(frag_mapping);
 80
 81		len = frag_len;
 82	}
 83
 84	flags &= ~TX_BD_LEN;
 85	txbd->tx_bd_len_flags_type = cpu_to_le32(((len) << TX_BD_LEN_SHIFT) | flags |
 86			TX_BD_FLAGS_PACKET_END);
 87	/* Sync TX BD */
 88	wmb();
 89	prod = NEXT_TX(prod);
 90	WRITE_ONCE(txr->tx_prod, prod);
 91
 92	return tx_buf;
 93}
 94
 95static void __bnxt_xmit_xdp(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
 96			    dma_addr_t mapping, u32 len, u16 rx_prod,
 97			    struct xdp_buff *xdp)
 98{
 99	struct bnxt_sw_tx_bd *tx_buf;
100
101	tx_buf = bnxt_xmit_bd(bp, txr, mapping, len, xdp);
102	tx_buf->rx_prod = rx_prod;
103	tx_buf->action = XDP_TX;
104
105}
106
107static void __bnxt_xmit_xdp_redirect(struct bnxt *bp,
108				     struct bnxt_tx_ring_info *txr,
109				     dma_addr_t mapping, u32 len,
110				     struct xdp_frame *xdpf)
111{
112	struct bnxt_sw_tx_bd *tx_buf;
113
114	tx_buf = bnxt_xmit_bd(bp, txr, mapping, len, NULL);
115	tx_buf->action = XDP_REDIRECT;
116	tx_buf->xdpf = xdpf;
117	dma_unmap_addr_set(tx_buf, mapping, mapping);
118	dma_unmap_len_set(tx_buf, len, len);
119}
120
121void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int budget)
122{
123	struct bnxt_tx_ring_info *txr = bnapi->tx_ring[0];
124	struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;
125	u16 tx_hw_cons = txr->tx_hw_cons;
126	bool rx_doorbell_needed = false;
127	struct bnxt_sw_tx_bd *tx_buf;
128	u16 tx_cons = txr->tx_cons;
129	u16 last_tx_cons = tx_cons;
130	int j, frags;
131
132	if (!budget)
133		return;
134
135	while (RING_TX(bp, tx_cons) != tx_hw_cons) {
136		tx_buf = &txr->tx_buf_ring[RING_TX(bp, tx_cons)];
137
138		if (tx_buf->action == XDP_REDIRECT) {
139			struct pci_dev *pdev = bp->pdev;
140
141			dma_unmap_single(&pdev->dev,
142					 dma_unmap_addr(tx_buf, mapping),
143					 dma_unmap_len(tx_buf, len),
144					 DMA_TO_DEVICE);
145			xdp_return_frame(tx_buf->xdpf);
146			tx_buf->action = 0;
147			tx_buf->xdpf = NULL;
148		} else if (tx_buf->action == XDP_TX) {
149			tx_buf->action = 0;
150			rx_doorbell_needed = true;
151			last_tx_cons = tx_cons;
152
153			frags = tx_buf->nr_frags;
154			for (j = 0; j < frags; j++) {
155				tx_cons = NEXT_TX(tx_cons);
156				tx_buf = &txr->tx_buf_ring[RING_TX(bp, tx_cons)];
157				page_pool_recycle_direct(rxr->page_pool, tx_buf->page);
158			}
159		} else {
160			bnxt_sched_reset_txr(bp, txr, tx_cons);
161			return;
162		}
163		tx_cons = NEXT_TX(tx_cons);
164	}
165
166	bnapi->events &= ~BNXT_TX_CMP_EVENT;
167	WRITE_ONCE(txr->tx_cons, tx_cons);
168	if (rx_doorbell_needed) {
169		tx_buf = &txr->tx_buf_ring[RING_TX(bp, last_tx_cons)];
170		bnxt_db_write(bp, &rxr->rx_db, tx_buf->rx_prod);
171
172	}
173}
174
175bool bnxt_xdp_attached(struct bnxt *bp, struct bnxt_rx_ring_info *rxr)
176{
177	struct bpf_prog *xdp_prog = READ_ONCE(rxr->xdp_prog);
178
179	return !!xdp_prog;
180}
181
182void bnxt_xdp_buff_init(struct bnxt *bp, struct bnxt_rx_ring_info *rxr,
183			u16 cons, u8 *data_ptr, unsigned int len,
184			struct xdp_buff *xdp)
185{
186	u32 buflen = BNXT_RX_PAGE_SIZE;
187	struct bnxt_sw_rx_bd *rx_buf;
188	struct pci_dev *pdev;
189	dma_addr_t mapping;
190	u32 offset;
191
192	pdev = bp->pdev;
193	rx_buf = &rxr->rx_buf_ring[cons];
194	offset = bp->rx_offset;
195
196	mapping = rx_buf->mapping - bp->rx_dma_offset;
197	dma_sync_single_for_cpu(&pdev->dev, mapping + offset, len, bp->rx_dir);
198
199	xdp_init_buff(xdp, buflen, &rxr->xdp_rxq);
200	xdp_prepare_buff(xdp, data_ptr - offset, offset, len, true);
201}
202
203void bnxt_xdp_buff_frags_free(struct bnxt_rx_ring_info *rxr,
204			      struct xdp_buff *xdp)
205{
206	struct skb_shared_info *shinfo;
207	int i;
208
209	if (!xdp || !xdp_buff_has_frags(xdp))
210		return;
211	shinfo = xdp_get_shared_info_from_buff(xdp);
212	for (i = 0; i < shinfo->nr_frags; i++) {
213		struct page *page = skb_frag_page(&shinfo->frags[i]);
214
215		page_pool_recycle_direct(rxr->page_pool, page);
216	}
217	shinfo->nr_frags = 0;
218}
219
220/* returns the following:
221 * true    - packet consumed by XDP and new buffer is allocated.
222 * false   - packet should be passed to the stack.
223 */
224bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
225		 struct xdp_buff *xdp, struct page *page, u8 **data_ptr,
226		 unsigned int *len, u8 *event)
227{
228	struct bpf_prog *xdp_prog = READ_ONCE(rxr->xdp_prog);
229	struct bnxt_tx_ring_info *txr;
230	struct bnxt_sw_rx_bd *rx_buf;
231	struct pci_dev *pdev;
232	dma_addr_t mapping;
233	u32 tx_needed = 1;
234	void *orig_data;
235	u32 tx_avail;
236	u32 offset;
237	u32 act;
238
239	if (!xdp_prog)
240		return false;
241
242	pdev = bp->pdev;
243	offset = bp->rx_offset;
244
245	txr = rxr->bnapi->tx_ring[0];
246	/* BNXT_RX_PAGE_MODE(bp) when XDP enabled */
247	orig_data = xdp->data;
248
249	act = bpf_prog_run_xdp(xdp_prog, xdp);
250
251	tx_avail = bnxt_tx_avail(bp, txr);
252	/* If the tx ring is not full, we must not update the rx producer yet
253	 * because we may still be transmitting on some BDs.
254	 */
255	if (tx_avail != bp->tx_ring_size)
256		*event &= ~BNXT_RX_EVENT;
257
258	*len = xdp->data_end - xdp->data;
259	if (orig_data != xdp->data) {
260		offset = xdp->data - xdp->data_hard_start;
261		*data_ptr = xdp->data_hard_start + offset;
262	}
263
264	switch (act) {
265	case XDP_PASS:
266		return false;
267
268	case XDP_TX:
269		rx_buf = &rxr->rx_buf_ring[cons];
270		mapping = rx_buf->mapping - bp->rx_dma_offset;
271
272		if (unlikely(xdp_buff_has_frags(xdp))) {
273			struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
274
275			tx_needed += sinfo->nr_frags;
276		}
277
278		if (tx_avail < tx_needed) {
279			trace_xdp_exception(bp->dev, xdp_prog, act);
280			bnxt_xdp_buff_frags_free(rxr, xdp);
281			bnxt_reuse_rx_data(rxr, cons, page);
282			return true;
283		}
284
285		dma_sync_single_for_device(&pdev->dev, mapping + offset, *len,
286					   bp->rx_dir);
287
288		*event &= ~BNXT_RX_EVENT;
289		*event |= BNXT_TX_EVENT;
290		__bnxt_xmit_xdp(bp, txr, mapping + offset, *len,
291				NEXT_RX(rxr->rx_prod), xdp);
292		bnxt_reuse_rx_data(rxr, cons, page);
293		return true;
294	case XDP_REDIRECT:
295		/* if we are calling this here then we know that the
296		 * redirect is coming from a frame received by the
297		 * bnxt_en driver.
298		 */
299
300		/* if we are unable to allocate a new buffer, abort and reuse */
301		if (bnxt_alloc_rx_data(bp, rxr, rxr->rx_prod, GFP_ATOMIC)) {
302			trace_xdp_exception(bp->dev, xdp_prog, act);
303			bnxt_xdp_buff_frags_free(rxr, xdp);
304			bnxt_reuse_rx_data(rxr, cons, page);
305			return true;
306		}
307
308		if (xdp_do_redirect(bp->dev, xdp, xdp_prog)) {
309			trace_xdp_exception(bp->dev, xdp_prog, act);
310			page_pool_recycle_direct(rxr->page_pool, page);
311			return true;
312		}
313
314		*event |= BNXT_REDIRECT_EVENT;
315		break;
316	default:
317		bpf_warn_invalid_xdp_action(bp->dev, xdp_prog, act);
318		fallthrough;
319	case XDP_ABORTED:
320		trace_xdp_exception(bp->dev, xdp_prog, act);
321		fallthrough;
322	case XDP_DROP:
323		bnxt_xdp_buff_frags_free(rxr, xdp);
324		bnxt_reuse_rx_data(rxr, cons, page);
325		break;
326	}
327	return true;
328}
329
330int bnxt_xdp_xmit(struct net_device *dev, int num_frames,
331		  struct xdp_frame **frames, u32 flags)
332{
333	struct bnxt *bp = netdev_priv(dev);
334	struct bpf_prog *xdp_prog = READ_ONCE(bp->xdp_prog);
335	struct pci_dev *pdev = bp->pdev;
336	struct bnxt_tx_ring_info *txr;
337	dma_addr_t mapping;
338	int nxmit = 0;
339	int ring;
340	int i;
341
342	if (!test_bit(BNXT_STATE_OPEN, &bp->state) ||
343	    !bp->tx_nr_rings_xdp ||
344	    !xdp_prog)
345		return -EINVAL;
346
347	ring = smp_processor_id() % bp->tx_nr_rings_xdp;
348	txr = &bp->tx_ring[ring];
349
350	if (READ_ONCE(txr->dev_state) == BNXT_DEV_STATE_CLOSING)
351		return -EINVAL;
352
353	if (static_branch_unlikely(&bnxt_xdp_locking_key))
354		spin_lock(&txr->xdp_tx_lock);
355
356	for (i = 0; i < num_frames; i++) {
357		struct xdp_frame *xdp = frames[i];
358
359		if (!bnxt_tx_avail(bp, txr))
360			break;
361
362		mapping = dma_map_single(&pdev->dev, xdp->data, xdp->len,
363					 DMA_TO_DEVICE);
364
365		if (dma_mapping_error(&pdev->dev, mapping))
366			break;
367
368		__bnxt_xmit_xdp_redirect(bp, txr, mapping, xdp->len, xdp);
369		nxmit++;
370	}
371
372	if (flags & XDP_XMIT_FLUSH) {
373		/* Sync BD data before updating doorbell */
374		wmb();
375		bnxt_db_write(bp, &txr->tx_db, txr->tx_prod);
376	}
377
378	if (static_branch_unlikely(&bnxt_xdp_locking_key))
379		spin_unlock(&txr->xdp_tx_lock);
380
381	return nxmit;
382}
383
384static int bnxt_xdp_set(struct bnxt *bp, struct bpf_prog *prog)
385{
386	struct net_device *dev = bp->dev;
387	int tx_xdp = 0, rc, tc;
388	struct bpf_prog *old;
389
390	netdev_assert_locked(dev);
391
392	if (prog && !prog->aux->xdp_has_frags &&
393	    bp->dev->mtu > BNXT_MAX_PAGE_MODE_MTU) {
394		netdev_warn(dev, "MTU %d larger than %d without XDP frag support.\n",
395			    bp->dev->mtu, BNXT_MAX_PAGE_MODE_MTU);
396		return -EOPNOTSUPP;
397	}
398	if (prog && bp->flags & BNXT_FLAG_HDS) {
399		netdev_warn(dev, "XDP is disallowed when HDS is enabled.\n");
400		return -EOPNOTSUPP;
401	}
402	if (!(bp->flags & BNXT_FLAG_SHARED_RINGS)) {
403		netdev_warn(dev, "ethtool rx/tx channels must be combined to support XDP.\n");
404		return -EOPNOTSUPP;
405	}
406	if (prog)
407		tx_xdp = bp->rx_nr_rings;
408
409	tc = bp->num_tc;
410	if (!tc)
411		tc = 1;
412	rc = bnxt_check_rings(bp, bp->tx_nr_rings_per_tc, bp->rx_nr_rings,
413			      true, tc, tx_xdp);
414	if (rc) {
415		netdev_warn(dev, "Unable to reserve enough TX rings to support XDP.\n");
416		return rc;
417	}
418	if (netif_running(dev))
419		bnxt_close_nic(bp, true, false);
420
421	old = xchg(&bp->xdp_prog, prog);
422	if (old)
423		bpf_prog_put(old);
424
425	if (prog) {
426		bnxt_set_rx_skb_mode(bp, true);
427		xdp_features_set_redirect_target_locked(dev, true);
428	} else {
429		xdp_features_clear_redirect_target_locked(dev);
430		bnxt_set_rx_skb_mode(bp, false);
431	}
432	bp->tx_nr_rings_xdp = tx_xdp;
433	bp->tx_nr_rings = bp->tx_nr_rings_per_tc * tc + tx_xdp;
434	bnxt_set_cp_rings(bp, true);
435	bnxt_set_tpa_flags(bp);
436	bnxt_set_ring_params(bp);
437
438	if (netif_running(dev))
439		return bnxt_open_nic(bp, true, false);
440
441	return 0;
442}
443
444int bnxt_xdp(struct net_device *dev, struct netdev_bpf *xdp)
445{
446	struct bnxt *bp = netdev_priv(dev);
447	int rc;
448
449	switch (xdp->command) {
450	case XDP_SETUP_PROG:
451		rc = bnxt_xdp_set(bp, xdp->prog);
452		break;
453	default:
454		rc = -EINVAL;
455		break;
456	}
457	return rc;
458}
459
460struct sk_buff *
461bnxt_xdp_build_skb(struct bnxt *bp, struct sk_buff *skb, u8 num_frags,
462		   struct page_pool *pool, struct xdp_buff *xdp)
463{
464	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
465
466	if (!skb)
467		return NULL;
468
469	xdp_update_skb_frags_info(skb, num_frags, sinfo->xdp_frags_size,
470				  BNXT_RX_PAGE_SIZE * num_frags,
471				  xdp_buff_get_skb_flags(xdp));
472	return skb;
473}