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 * $FreeBSD$ 28 */ 29 30 #include <net/netmap.h> 31 #include <sys/selinfo.h> 32 #include <vm/vm.h> 33 #include <vm/pmap.h> /* vtophys ? */ 34 #include <dev/netmap/netmap_kern.h> 35 36 /* Register and unregister. */ 37 static int 38 vtnet_netmap_reg(struct netmap_adapter *na, int state) 39 { 40 struct ifnet *ifp = na->ifp; 41 struct vtnet_softc *sc = ifp->if_softc; 42 43 /* 44 * Trigger a device reinit, asking vtnet_init_locked() to 45 * also enter or exit netmap mode. 46 */ 47 VTNET_CORE_LOCK(sc); 48 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 49 vtnet_init_locked(sc, state ? VTNET_INIT_NETMAP_ENTER 50 : VTNET_INIT_NETMAP_EXIT); 51 VTNET_CORE_UNLOCK(sc); 52 53 return (0); 54 } 55 56 57 /* Reconcile kernel and user view of the transmit ring. */ 58 static int 59 vtnet_netmap_txsync(struct netmap_kring *kring, int flags) 60 { 61 struct netmap_adapter *na = kring->na; 62 struct ifnet *ifp = na->ifp; 63 struct netmap_ring *ring = kring->ring; 64 u_int ring_nr = kring->ring_id; 65 u_int nm_i; /* index into the netmap ring */ 66 u_int const lim = kring->nkr_num_slots - 1; 67 u_int const head = kring->rhead; 68 69 /* device-specific */ 70 struct vtnet_softc *sc = ifp->if_softc; 71 struct vtnet_txq *txq = &sc->vtnet_txqs[ring_nr]; 72 struct virtqueue *vq = txq->vtntx_vq; 73 int interrupts = !(kring->nr_kflags & NKR_NOINTR); 74 u_int n; 75 76 /* 77 * First part: process new packets to send. 78 */ 79 80 nm_i = kring->nr_hwcur; 81 if (nm_i != head) { /* we have new packets to send */ 82 struct sglist *sg = txq->vtntx_sg; 83 84 for (; nm_i != head; nm_i = nm_next(nm_i, lim)) { 85 /* we use an empty header here */ 86 struct netmap_slot *slot = &ring->slot[nm_i]; 87 u_int len = slot->len; 88 uint64_t paddr; 89 void *addr = PNMB(na, slot, &paddr); 90 int err; 91 92 NM_CHECK_ADDR_LEN(na, addr, len); 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, 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 migth 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 153 vtnet_netmap_kring_refill(struct netmap_kring *kring, u_int num) 154 { 155 struct netmap_adapter *na = kring->na; 156 struct ifnet *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 = ifp->if_softc; 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 paddr; 175 void *addr = PNMB(na, slot, &paddr); 176 int err; 177 178 if (addr == NETMAP_BUF_BASE(na)) { /* bad buf */ 179 if (netmap_ring_reinit(kring)) 180 return EFAULT; 181 } 182 183 slot->flags &= ~NS_BUF_CHANGED; 184 sglist_reset(&sg); 185 err = sglist_append(&sg, &rxq->vtnrx_shrhdr, sc->vtnet_hdr_size); 186 err |= sglist_append_phys(&sg, paddr, NETMAP_BUF_SIZE(na)); 187 KASSERT(err == 0, ("%s: cannot append to sglist %d", 188 __func__, err)); 189 /* writable for the host */ 190 err = virtqueue_enqueue(vq, /*cookie=*/rxq, &sg, 191 /*readable=*/0, /*writeable=*/sg.sg_nseg); 192 if (unlikely(err)) { 193 nm_prerr("virtqueue_enqueue(%s) failed: %d", 194 kring->name, err); 195 break; 196 } 197 } 198 rxq->vtnrx_nm_refill = nm_i; 199 200 return num == 0 ? 0 : ENOSPC; 201 } 202 203 /* 204 * Publish netmap buffers on a RX virtqueue. 205 * Returns -1 if this virtqueue is not being opened in netmap mode. 206 * If the virtqueue is being opened in netmap mode, return 0 on success and 207 * a positive error code on failure. 208 */ 209 static int 210 vtnet_netmap_rxq_populate(struct vtnet_rxq *rxq) 211 { 212 struct netmap_adapter *na = NA(rxq->vtnrx_sc->vtnet_ifp); 213 struct netmap_kring *kring; 214 struct netmap_slot *slot; 215 int error; 216 int num; 217 218 slot = netmap_reset(na, NR_RX, rxq->vtnrx_id, 0); 219 if (slot == NULL) 220 return -1; 221 kring = na->rx_rings[rxq->vtnrx_id]; 222 223 /* 224 * Expose all the RX netmap buffers we can. In case of no indirect 225 * buffers, the number of netmap slots in the RX ring matches the 226 * maximum number of 2-elements sglist that the RX virtqueue can 227 * accommodate. We need to start from kring->nr_hwtail, which is 0 228 * on the first netmap register and may be different from 0 if a 229 * virtio re-init (caused by a netma register or i.e., ifconfig) 230 * happens while the device is in use by netmap. 231 */ 232 rxq->vtnrx_nm_refill = kring->nr_hwtail; 233 num = na->num_rx_desc - 1 - nm_kr_rxspace(kring); 234 error = vtnet_netmap_kring_refill(kring, num); 235 virtqueue_notify(rxq->vtnrx_vq); 236 237 return error; 238 } 239 240 /* Reconcile kernel and user view of the receive ring. */ 241 static int 242 vtnet_netmap_rxsync(struct netmap_kring *kring, int flags) 243 { 244 struct netmap_adapter *na = kring->na; 245 struct ifnet *ifp = na->ifp; 246 struct netmap_ring *ring = kring->ring; 247 u_int ring_nr = kring->ring_id; 248 u_int nm_i; /* index into the netmap ring */ 249 u_int const lim = kring->nkr_num_slots - 1; 250 u_int const head = kring->rhead; 251 int force_update = (flags & NAF_FORCE_READ) || 252 (kring->nr_kflags & NKR_PENDINTR); 253 int interrupts = !(kring->nr_kflags & NKR_NOINTR); 254 255 /* device-specific */ 256 struct vtnet_softc *sc = ifp->if_softc; 257 struct vtnet_rxq *rxq = &sc->vtnet_rxqs[ring_nr]; 258 struct virtqueue *vq = rxq->vtnrx_vq; 259 260 /* 261 * First part: import newly received packets. 262 * Only accept our own buffers (matching the token). We should only get 263 * matching buffers. The hwtail should never overrun hwcur, because 264 * we publish only N-1 receive buffers (and not N). 265 * In any case we must not leave this routine with the interrupts 266 * disabled, pending packets in the VQ and hwtail == (hwcur - 1), 267 * otherwise the pending packets could stall. 268 */ 269 if (netmap_no_pendintr || force_update) { 270 uint32_t hwtail_lim = nm_prev(kring->nr_hwcur, lim); 271 void *token; 272 273 vtnet_rxq_disable_intr(rxq); 274 275 nm_i = kring->nr_hwtail; 276 for (;;) { 277 int len; 278 token = virtqueue_dequeue(vq, &len); 279 if (token == NULL) { 280 /* 281 * Enable the interrupts again and double-check 282 * for more work. We can go on until we win the 283 * race condition, since we are not replenishing 284 * in the meanwhile, and thus we will process at 285 * most N-1 slots. 286 */ 287 if (interrupts && vtnet_rxq_enable_intr(rxq)) { 288 vtnet_rxq_disable_intr(rxq); 289 continue; 290 } 291 break; 292 } 293 if (unlikely(token != (void *)rxq)) { 294 nm_prerr("BUG: RX token mismatch"); 295 } else { 296 if (nm_i == hwtail_lim) { 297 KASSERT(false, ("hwtail would " 298 "overrun hwcur")); 299 } 300 301 /* Skip the virtio-net header. */ 302 len -= sc->vtnet_hdr_size; 303 if (unlikely(len < 0)) { 304 nm_prlim(1, "Truncated virtio-net-header, " 305 "missing %d bytes", -len); 306 len = 0; 307 } 308 ring->slot[nm_i].len = len; 309 ring->slot[nm_i].flags = 0; 310 nm_i = nm_next(nm_i, lim); 311 } 312 } 313 kring->nr_hwtail = nm_i; 314 kring->nr_kflags &= ~NKR_PENDINTR; 315 } 316 317 /* 318 * Second part: skip past packets that userspace has released. 319 */ 320 nm_i = kring->nr_hwcur; /* netmap ring index */ 321 if (nm_i != head) { 322 int released; 323 int error; 324 325 released = head - nm_i; 326 if (released < 0) 327 released += kring->nkr_num_slots; 328 error = vtnet_netmap_kring_refill(kring, released); 329 if (error) { 330 nm_prerr("Failed to replenish RX VQ with %u sgs", 331 released); 332 return error; 333 } 334 kring->nr_hwcur = head; 335 virtqueue_notify(vq); 336 } 337 338 nm_prdis("h %d c %d t %d hwcur %d hwtail %d", kring->rhead, 339 kring->rcur, kring->rtail, kring->nr_hwcur, kring->nr_hwtail); 340 341 return 0; 342 } 343 344 345 /* Enable/disable interrupts on all virtqueues. */ 346 static void 347 vtnet_netmap_intr(struct netmap_adapter *na, int state) 348 { 349 struct vtnet_softc *sc = na->ifp->if_softc; 350 int i; 351 352 for (i = 0; i < sc->vtnet_max_vq_pairs; i++) { 353 struct vtnet_rxq *rxq = &sc->vtnet_rxqs[i]; 354 struct vtnet_txq *txq = &sc->vtnet_txqs[i]; 355 struct virtqueue *txvq = txq->vtntx_vq; 356 357 if (state) { 358 vtnet_rxq_enable_intr(rxq); 359 virtqueue_enable_intr(txvq); 360 } else { 361 vtnet_rxq_disable_intr(rxq); 362 virtqueue_disable_intr(txvq); 363 } 364 } 365 } 366 367 static int 368 vtnet_netmap_tx_slots(struct vtnet_softc *sc) 369 { 370 int div; 371 372 /* We need to prepend a virtio-net header to each netmap buffer to be 373 * transmitted, therefore calling virtqueue_enqueue() passing sglist 374 * with 2 elements. 375 * TX virtqueues use indirect descriptors if the feature was negotiated 376 * with the host, and if sc->vtnet_tx_nsegs > 1. With indirect 377 * descriptors, a single virtio descriptor is sufficient to reference 378 * each TX sglist. Without them, we need two separate virtio descriptors 379 * for each TX sglist. We therefore compute the number of netmap TX 380 * slots according to these assumptions. 381 */ 382 if ((sc->vtnet_flags & VTNET_FLAG_INDIRECT) && sc->vtnet_tx_nsegs > 1) 383 div = 1; 384 else 385 div = 2; 386 387 return virtqueue_size(sc->vtnet_txqs[0].vtntx_vq) / div; 388 } 389 390 static int 391 vtnet_netmap_rx_slots(struct vtnet_softc *sc) 392 { 393 int div; 394 395 /* We need to prepend a virtio-net header to each netmap buffer to be 396 * received, therefore calling virtqueue_enqueue() passing sglist 397 * with 2 elements. 398 * RX virtqueues use indirect descriptors if the feature was negotiated 399 * with the host, and if sc->vtnet_rx_nsegs > 1. With indirect 400 * descriptors, a single virtio descriptor is sufficient to reference 401 * each RX sglist. Without them, we need two separate virtio descriptors 402 * for each RX sglist. We therefore compute the number of netmap RX 403 * slots according to these assumptions. 404 */ 405 if ((sc->vtnet_flags & VTNET_FLAG_INDIRECT) && sc->vtnet_rx_nsegs > 1) 406 div = 1; 407 else 408 div = 2; 409 410 return virtqueue_size(sc->vtnet_rxqs[0].vtnrx_vq) / div; 411 } 412 413 static int 414 vtnet_netmap_config(struct netmap_adapter *na, struct nm_config_info *info) 415 { 416 struct vtnet_softc *sc = na->ifp->if_softc; 417 418 info->num_tx_rings = sc->vtnet_act_vq_pairs; 419 info->num_rx_rings = sc->vtnet_act_vq_pairs; 420 info->num_tx_descs = vtnet_netmap_tx_slots(sc); 421 info->num_rx_descs = vtnet_netmap_rx_slots(sc); 422 info->rx_buf_maxsize = NETMAP_BUF_SIZE(na); 423 424 return 0; 425 } 426 427 static void 428 vtnet_netmap_attach(struct vtnet_softc *sc) 429 { 430 struct netmap_adapter na; 431 432 bzero(&na, sizeof(na)); 433 434 na.ifp = sc->vtnet_ifp; 435 na.na_flags = 0; 436 na.num_tx_desc = vtnet_netmap_tx_slots(sc); 437 na.num_rx_desc = vtnet_netmap_rx_slots(sc); 438 na.num_tx_rings = na.num_rx_rings = sc->vtnet_max_vq_pairs; 439 na.rx_buf_maxsize = 0; 440 na.nm_register = vtnet_netmap_reg; 441 na.nm_txsync = vtnet_netmap_txsync; 442 na.nm_rxsync = vtnet_netmap_rxsync; 443 na.nm_intr = vtnet_netmap_intr; 444 na.nm_config = vtnet_netmap_config; 445 446 netmap_attach(&na); 447 448 nm_prinf("vtnet attached txq=%d, txd=%d rxq=%d, rxd=%d", 449 na.num_tx_rings, na.num_tx_desc, 450 na.num_tx_rings, na.num_rx_desc); 451 } 452 /* end of file */ 453