1 /*
2 * Copyright (C) 2014-2018 Vincenzo Maffione, Luigi Rizzo.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 /*
27 */
28
29 #include <net/netmap.h>
30 #include <sys/selinfo.h>
31 #include <vm/vm.h>
32 #include <vm/pmap.h> /* vtophys ? */
33 #include <dev/netmap/netmap_kern.h>
34
35 /* Register and unregister. */
36 static int
vtnet_netmap_reg(struct netmap_adapter * na,int state)37 vtnet_netmap_reg(struct netmap_adapter *na, int state)
38 {
39 if_t ifp = na->ifp;
40 struct vtnet_softc *sc = if_getsoftc(ifp);
41
42 /*
43 * Trigger a device reinit, asking vtnet_init_locked() to
44 * also enter or exit netmap mode.
45 */
46 VTNET_CORE_LOCK(sc);
47 if_setdrvflagbits(ifp, 0, IFF_DRV_RUNNING);
48 vtnet_init_locked(sc, state ? VTNET_INIT_NETMAP_ENTER
49 : VTNET_INIT_NETMAP_EXIT);
50 VTNET_CORE_UNLOCK(sc);
51
52 return (0);
53 }
54
55
56 /* Reconcile kernel and user view of the transmit ring. */
57 static int
vtnet_netmap_txsync(struct netmap_kring * kring,int flags)58 vtnet_netmap_txsync(struct netmap_kring *kring, int flags)
59 {
60 struct netmap_adapter *na = kring->na;
61 if_t ifp = na->ifp;
62 struct netmap_ring *ring = kring->ring;
63 u_int ring_nr = kring->ring_id;
64 u_int nm_i; /* index into the netmap ring */
65 u_int const lim = kring->nkr_num_slots - 1;
66 u_int const head = kring->rhead;
67
68 /* device-specific */
69 struct vtnet_softc *sc = if_getsoftc(ifp);
70 struct vtnet_txq *txq = &sc->vtnet_txqs[ring_nr];
71 struct virtqueue *vq = txq->vtntx_vq;
72 int interrupts = !(kring->nr_kflags & NKR_NOINTR);
73 u_int n;
74
75 /*
76 * First part: process new packets to send.
77 */
78
79 nm_i = kring->nr_hwcur;
80 if (nm_i != head) { /* we have new packets to send */
81 struct sglist *sg = txq->vtntx_sg;
82
83 for (; nm_i != head; nm_i = nm_next(nm_i, lim)) {
84 /* we use an empty header here */
85 struct netmap_slot *slot = &ring->slot[nm_i];
86 uint64_t offset = nm_get_offset(kring, slot);
87 u_int len = slot->len;
88 uint64_t paddr;
89 int err;
90
91 (void)PNMB(na, slot, &paddr);
92 NM_CHECK_ADDR_LEN_OFF(na, len, offset);
93
94 slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
95 /* Initialize the scatterlist, expose it to the hypervisor,
96 * and kick the hypervisor (if necessary).
97 */
98 sglist_reset(sg); // cheap
99 err = sglist_append(sg, &txq->vtntx_shrhdr, sc->vtnet_hdr_size);
100 err |= sglist_append_phys(sg, paddr + offset, len);
101 KASSERT(err == 0, ("%s: cannot append to sglist %d",
102 __func__, err));
103 err = virtqueue_enqueue(vq, /*cookie=*/txq, sg,
104 /*readable=*/sg->sg_nseg,
105 /*writeable=*/0);
106 if (unlikely(err)) {
107 if (err != ENOSPC)
108 nm_prerr("virtqueue_enqueue(%s) failed: %d",
109 kring->name, err);
110 break;
111 }
112 }
113
114 virtqueue_notify(vq);
115
116 /* Update hwcur depending on where we stopped. */
117 kring->nr_hwcur = nm_i; /* note we might break early */
118 }
119
120 /* Free used slots. We only consider our own used buffers, recognized
121 * by the token we passed to virtqueue_enqueue.
122 */
123 n = 0;
124 for (;;) {
125 void *token = virtqueue_dequeue(vq, NULL);
126 if (token == NULL)
127 break;
128 if (unlikely(token != (void *)txq))
129 nm_prerr("BUG: TX token mismatch");
130 else
131 n++;
132 }
133 if (n > 0) {
134 kring->nr_hwtail += n;
135 if (kring->nr_hwtail > lim)
136 kring->nr_hwtail -= lim + 1;
137 }
138
139 if (interrupts && virtqueue_nfree(vq) < 32)
140 virtqueue_postpone_intr(vq, VQ_POSTPONE_LONG);
141
142 return 0;
143 }
144
145 /*
146 * Publish 'num 'netmap receive buffers to the host, starting
147 * from the next available one (rx->vtnrx_nm_refill).
148 * Return a positive error code on error, and 0 on success.
149 * If we could not publish all of the buffers that's an error,
150 * since the netmap ring and the virtqueue would go out of sync.
151 */
152 static int
vtnet_netmap_kring_refill(struct netmap_kring * kring,u_int num)153 vtnet_netmap_kring_refill(struct netmap_kring *kring, u_int num)
154 {
155 struct netmap_adapter *na = kring->na;
156 if_t ifp = na->ifp;
157 struct netmap_ring *ring = kring->ring;
158 u_int ring_nr = kring->ring_id;
159 u_int const lim = kring->nkr_num_slots - 1;
160 u_int nm_i;
161
162 /* device-specific */
163 struct vtnet_softc *sc = if_getsoftc(ifp);
164 struct vtnet_rxq *rxq = &sc->vtnet_rxqs[ring_nr];
165 struct virtqueue *vq = rxq->vtnrx_vq;
166
167 /* use a local sglist, default might be short */
168 struct sglist_seg ss[2];
169 struct sglist sg = { ss, 0, 0, 2 };
170
171 for (nm_i = rxq->vtnrx_nm_refill; num > 0;
172 nm_i = nm_next(nm_i, lim), num--) {
173 struct netmap_slot *slot = &ring->slot[nm_i];
174 uint64_t offset = nm_get_offset(kring, slot);
175 uint64_t paddr;
176 void *addr = PNMB(na, slot, &paddr);
177 int err;
178
179 if (addr == NETMAP_BUF_BASE(na)) { /* bad buf */
180 netmap_ring_reinit(kring);
181 return EFAULT;
182 }
183
184 slot->flags &= ~NS_BUF_CHANGED;
185 sglist_reset(&sg);
186 err = sglist_append(&sg, &rxq->vtnrx_shrhdr, sc->vtnet_hdr_size);
187 err |= sglist_append_phys(&sg, paddr + offset,
188 NETMAP_BUF_SIZE(na) - offset);
189 KASSERT(err == 0, ("%s: cannot append to sglist %d",
190 __func__, err));
191 /* writable for the host */
192 err = virtqueue_enqueue(vq, /*cookie=*/rxq, &sg,
193 /*readable=*/0, /*writeable=*/sg.sg_nseg);
194 if (unlikely(err)) {
195 nm_prerr("virtqueue_enqueue(%s) failed: %d",
196 kring->name, err);
197 break;
198 }
199 }
200 rxq->vtnrx_nm_refill = nm_i;
201
202 return num == 0 ? 0 : ENOSPC;
203 }
204
205 /*
206 * Publish netmap buffers on a RX virtqueue.
207 * Returns -1 if this virtqueue is not being opened in netmap mode.
208 * If the virtqueue is being opened in netmap mode, return 0 on success and
209 * a positive error code on failure.
210 */
211 static int
vtnet_netmap_rxq_populate(struct vtnet_rxq * rxq)212 vtnet_netmap_rxq_populate(struct vtnet_rxq *rxq)
213 {
214 struct netmap_adapter *na = NA(rxq->vtnrx_sc->vtnet_ifp);
215 struct netmap_kring *kring;
216 struct netmap_slot *slot;
217 int error;
218 int num;
219
220 slot = netmap_reset(na, NR_RX, rxq->vtnrx_id, 0);
221 if (slot == NULL)
222 return -1;
223 kring = na->rx_rings[rxq->vtnrx_id];
224
225 /*
226 * Expose all the RX netmap buffers we can. In case of no indirect
227 * buffers, the number of netmap slots in the RX ring matches the
228 * maximum number of 2-elements sglist that the RX virtqueue can
229 * accommodate. We need to start from kring->nr_hwtail, which is 0
230 * on the first netmap register and may be different from 0 if a
231 * virtio re-init (caused by a netma register or i.e., ifconfig)
232 * happens while the device is in use by netmap.
233 */
234 rxq->vtnrx_nm_refill = kring->nr_hwtail;
235 num = na->num_rx_desc - 1 - nm_kr_rxspace(kring);
236 error = vtnet_netmap_kring_refill(kring, num);
237 virtqueue_notify(rxq->vtnrx_vq);
238
239 return error;
240 }
241
242 /* Reconcile kernel and user view of the receive ring. */
243 static int
vtnet_netmap_rxsync(struct netmap_kring * kring,int flags)244 vtnet_netmap_rxsync(struct netmap_kring *kring, int flags)
245 {
246 struct netmap_adapter *na = kring->na;
247 if_t ifp = na->ifp;
248 struct netmap_ring *ring = kring->ring;
249 u_int ring_nr = kring->ring_id;
250 u_int nm_i; /* index into the netmap ring */
251 u_int const lim = kring->nkr_num_slots - 1;
252 u_int const head = kring->rhead;
253 int force_update = (flags & NAF_FORCE_READ) ||
254 (kring->nr_kflags & NKR_PENDINTR);
255 int interrupts = !(kring->nr_kflags & NKR_NOINTR);
256
257 /* device-specific */
258 struct vtnet_softc *sc = if_getsoftc(ifp);
259 struct vtnet_rxq *rxq = &sc->vtnet_rxqs[ring_nr];
260 struct virtqueue *vq = rxq->vtnrx_vq;
261
262 /*
263 * First part: import newly received packets.
264 * Only accept our own buffers (matching the token). We should only get
265 * matching buffers. The hwtail should never overrun hwcur, because
266 * we publish only N-1 receive buffers (and not N).
267 * In any case we must not leave this routine with the interrupts
268 * disabled, pending packets in the VQ and hwtail == (hwcur - 1),
269 * otherwise the pending packets could stall.
270 */
271 if (netmap_no_pendintr || force_update) {
272 uint32_t hwtail_lim = nm_prev(kring->nr_hwcur, lim);
273 void *token;
274
275 vtnet_rxq_disable_intr(rxq);
276
277 nm_i = kring->nr_hwtail;
278 for (;;) {
279 int len;
280 token = virtqueue_dequeue(vq, &len);
281 if (token == NULL) {
282 /*
283 * Enable the interrupts again and double-check
284 * for more work. We can go on until we win the
285 * race condition, since we are not replenishing
286 * in the meanwhile, and thus we will process at
287 * most N-1 slots.
288 */
289 if (interrupts && vtnet_rxq_enable_intr(rxq)) {
290 vtnet_rxq_disable_intr(rxq);
291 continue;
292 }
293 break;
294 }
295 if (unlikely(token != (void *)rxq)) {
296 nm_prerr("BUG: RX token mismatch");
297 } else {
298 if (nm_i == hwtail_lim) {
299 KASSERT(false, ("hwtail would "
300 "overrun hwcur"));
301 }
302
303 /* Skip the virtio-net header. */
304 len -= sc->vtnet_hdr_size;
305 if (unlikely(len < 0)) {
306 nm_prlim(1, "Truncated virtio-net-header, "
307 "missing %d bytes", -len);
308 len = 0;
309 }
310 ring->slot[nm_i].len = len;
311 ring->slot[nm_i].flags = 0;
312 nm_i = nm_next(nm_i, lim);
313 }
314 }
315 kring->nr_hwtail = nm_i;
316 kring->nr_kflags &= ~NKR_PENDINTR;
317 }
318
319 /*
320 * Second part: skip past packets that userspace has released.
321 */
322 nm_i = kring->nr_hwcur; /* netmap ring index */
323 if (nm_i != head) {
324 int released;
325 int error;
326
327 released = head - nm_i;
328 if (released < 0)
329 released += kring->nkr_num_slots;
330 error = vtnet_netmap_kring_refill(kring, released);
331 if (error) {
332 nm_prerr("Failed to replenish RX VQ with %u sgs",
333 released);
334 return error;
335 }
336 kring->nr_hwcur = head;
337 virtqueue_notify(vq);
338 }
339
340 nm_prdis("h %d c %d t %d hwcur %d hwtail %d", kring->rhead,
341 kring->rcur, kring->rtail, kring->nr_hwcur, kring->nr_hwtail);
342
343 return 0;
344 }
345
346
347 /* Enable/disable interrupts on all virtqueues. */
348 static void
vtnet_netmap_intr(struct netmap_adapter * na,int state)349 vtnet_netmap_intr(struct netmap_adapter *na, int state)
350 {
351 struct vtnet_softc *sc = if_getsoftc(na->ifp);
352 int i;
353
354 for (i = 0; i < sc->vtnet_max_vq_pairs; i++) {
355 struct vtnet_rxq *rxq = &sc->vtnet_rxqs[i];
356 struct vtnet_txq *txq = &sc->vtnet_txqs[i];
357 struct virtqueue *txvq = txq->vtntx_vq;
358
359 if (state) {
360 vtnet_rxq_enable_intr(rxq);
361 virtqueue_enable_intr(txvq);
362 } else {
363 vtnet_rxq_disable_intr(rxq);
364 virtqueue_disable_intr(txvq);
365 }
366 }
367 }
368
369 static int
vtnet_netmap_tx_slots(struct vtnet_softc * sc)370 vtnet_netmap_tx_slots(struct vtnet_softc *sc)
371 {
372 int div;
373
374 /* We need to prepend a virtio-net header to each netmap buffer to be
375 * transmitted, therefore calling virtqueue_enqueue() passing sglist
376 * with 2 elements.
377 * TX virtqueues use indirect descriptors if the feature was negotiated
378 * with the host, and if sc->vtnet_tx_nsegs > 1. With indirect
379 * descriptors, a single virtio descriptor is sufficient to reference
380 * each TX sglist. Without them, we need two separate virtio descriptors
381 * for each TX sglist. We therefore compute the number of netmap TX
382 * slots according to these assumptions.
383 */
384 if ((sc->vtnet_flags & VTNET_FLAG_INDIRECT) && sc->vtnet_tx_nsegs > 1)
385 div = 1;
386 else
387 div = 2;
388
389 return virtqueue_size(sc->vtnet_txqs[0].vtntx_vq) / div;
390 }
391
392 static int
vtnet_netmap_rx_slots(struct vtnet_softc * sc)393 vtnet_netmap_rx_slots(struct vtnet_softc *sc)
394 {
395 int div;
396
397 /* We need to prepend a virtio-net header to each netmap buffer to be
398 * received, therefore calling virtqueue_enqueue() passing sglist
399 * with 2 elements.
400 * RX virtqueues use indirect descriptors if the feature was negotiated
401 * with the host, and if sc->vtnet_rx_nsegs > 1. With indirect
402 * descriptors, a single virtio descriptor is sufficient to reference
403 * each RX sglist. Without them, we need two separate virtio descriptors
404 * for each RX sglist. We therefore compute the number of netmap RX
405 * slots according to these assumptions.
406 */
407 if ((sc->vtnet_flags & VTNET_FLAG_INDIRECT) && sc->vtnet_rx_nsegs > 1)
408 div = 1;
409 else
410 div = 2;
411
412 return virtqueue_size(sc->vtnet_rxqs[0].vtnrx_vq) / div;
413 }
414
415 static int
vtnet_netmap_config(struct netmap_adapter * na,struct nm_config_info * info)416 vtnet_netmap_config(struct netmap_adapter *na, struct nm_config_info *info)
417 {
418 struct vtnet_softc *sc = if_getsoftc(na->ifp);
419
420 info->num_tx_rings = sc->vtnet_act_vq_pairs;
421 info->num_rx_rings = sc->vtnet_act_vq_pairs;
422 info->num_tx_descs = vtnet_netmap_tx_slots(sc);
423 info->num_rx_descs = vtnet_netmap_rx_slots(sc);
424 info->rx_buf_maxsize = NETMAP_BUF_SIZE(na);
425
426 return 0;
427 }
428
429 static void
vtnet_netmap_attach(struct vtnet_softc * sc)430 vtnet_netmap_attach(struct vtnet_softc *sc)
431 {
432 struct netmap_adapter na;
433
434 bzero(&na, sizeof(na));
435
436 na.ifp = sc->vtnet_ifp;
437 na.na_flags = NAF_OFFSETS;
438 na.num_tx_desc = vtnet_netmap_tx_slots(sc);
439 na.num_rx_desc = vtnet_netmap_rx_slots(sc);
440 na.num_tx_rings = na.num_rx_rings = sc->vtnet_max_vq_pairs;
441 na.rx_buf_maxsize = 0;
442 na.nm_register = vtnet_netmap_reg;
443 na.nm_txsync = vtnet_netmap_txsync;
444 na.nm_rxsync = vtnet_netmap_rxsync;
445 na.nm_intr = vtnet_netmap_intr;
446 na.nm_config = vtnet_netmap_config;
447
448 netmap_attach(&na);
449
450 nm_prinf("vtnet attached txq=%d, txd=%d rxq=%d, rxd=%d",
451 na.num_tx_rings, na.num_tx_desc,
452 na.num_tx_rings, na.num_rx_desc);
453 }
454 /* end of file */
455