xref: /freebsd/usr.sbin/bhyve/pci_virtio_net.c (revision e17f5b1d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2011 NetApp, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/linker_set.h>
36 #include <sys/select.h>
37 #include <sys/uio.h>
38 #include <sys/ioctl.h>
39 #include <machine/vmm_snapshot.h>
40 #include <net/ethernet.h>
41 #include <net/if.h> /* IFNAMSIZ */
42 
43 #include <err.h>
44 #include <errno.h>
45 #include <fcntl.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <stdint.h>
49 #include <string.h>
50 #include <strings.h>
51 #include <unistd.h>
52 #include <assert.h>
53 #include <pthread.h>
54 #include <pthread_np.h>
55 
56 #include "bhyverun.h"
57 #include "debug.h"
58 #include "pci_emul.h"
59 #include "mevent.h"
60 #include "virtio.h"
61 #include "net_utils.h"
62 #include "net_backends.h"
63 #include "iov.h"
64 
65 #define VTNET_RINGSZ	1024
66 
67 #define VTNET_MAXSEGS	256
68 
69 #define VTNET_MAX_PKT_LEN	(65536 + 64)
70 
71 #define VTNET_MIN_MTU	ETHERMIN
72 #define VTNET_MAX_MTU	65535
73 
74 #define VTNET_S_HOSTCAPS      \
75   ( VIRTIO_NET_F_MAC | VIRTIO_NET_F_STATUS | \
76     VIRTIO_F_NOTIFY_ON_EMPTY | VIRTIO_RING_F_INDIRECT_DESC)
77 
78 /*
79  * PCI config-space "registers"
80  */
81 struct virtio_net_config {
82 	uint8_t  mac[6];
83 	uint16_t status;
84 	uint16_t max_virtqueue_pairs;
85 	uint16_t mtu;
86 } __packed;
87 
88 /*
89  * Queue definitions.
90  */
91 #define VTNET_RXQ	0
92 #define VTNET_TXQ	1
93 #define VTNET_CTLQ	2	/* NB: not yet supported */
94 
95 #define VTNET_MAXQ	3
96 
97 /*
98  * Debug printf
99  */
100 static int pci_vtnet_debug;
101 #define DPRINTF(params) if (pci_vtnet_debug) PRINTLN params
102 #define WPRINTF(params) PRINTLN params
103 
104 /*
105  * Per-device softc
106  */
107 struct pci_vtnet_softc {
108 	struct virtio_softc vsc_vs;
109 	struct vqueue_info vsc_queues[VTNET_MAXQ - 1];
110 	pthread_mutex_t vsc_mtx;
111 
112 	net_backend_t	*vsc_be;
113 
114 	int		resetting;	/* protected by tx_mtx */
115 
116 	uint64_t	vsc_features;	/* negotiated features */
117 
118 	pthread_mutex_t	rx_mtx;
119 	int		rx_merge;	/* merged rx bufs in use */
120 
121 	pthread_t 	tx_tid;
122 	pthread_mutex_t	tx_mtx;
123 	pthread_cond_t	tx_cond;
124 	int		tx_in_progress;
125 
126 	size_t		vhdrlen;
127 	size_t		be_vhdrlen;
128 
129 	struct virtio_net_config vsc_config;
130 	struct virtio_consts vsc_consts;
131 };
132 
133 static void pci_vtnet_reset(void *);
134 /* static void pci_vtnet_notify(void *, struct vqueue_info *); */
135 static int pci_vtnet_cfgread(void *, int, int, uint32_t *);
136 static int pci_vtnet_cfgwrite(void *, int, int, uint32_t);
137 static void pci_vtnet_neg_features(void *, uint64_t);
138 #ifdef BHYVE_SNAPSHOT
139 static void pci_vtnet_pause(void *);
140 static void pci_vtnet_resume(void *);
141 static int pci_vtnet_snapshot(void *, struct vm_snapshot_meta *);
142 #endif
143 
144 static struct virtio_consts vtnet_vi_consts = {
145 	"vtnet",		/* our name */
146 	VTNET_MAXQ - 1,		/* we currently support 2 virtqueues */
147 	sizeof(struct virtio_net_config), /* config reg size */
148 	pci_vtnet_reset,	/* reset */
149 	NULL,			/* device-wide qnotify -- not used */
150 	pci_vtnet_cfgread,	/* read PCI config */
151 	pci_vtnet_cfgwrite,	/* write PCI config */
152 	pci_vtnet_neg_features,	/* apply negotiated features */
153 	VTNET_S_HOSTCAPS,	/* our capabilities */
154 #ifdef BHYVE_SNAPSHOT
155 	pci_vtnet_pause,	/* pause rx/tx threads */
156 	pci_vtnet_resume,	/* resume rx/tx threads */
157 	pci_vtnet_snapshot,	/* save / restore device state */
158 #endif
159 };
160 
161 static void
162 pci_vtnet_reset(void *vsc)
163 {
164 	struct pci_vtnet_softc *sc = vsc;
165 
166 	DPRINTF(("vtnet: device reset requested !"));
167 
168 	/* Acquire the RX lock to block RX processing. */
169 	pthread_mutex_lock(&sc->rx_mtx);
170 
171 	/*
172 	 * Make sure receive operation is disabled at least until we
173 	 * re-negotiate the features, since receive operation depends
174 	 * on the value of sc->rx_merge and the header length, which
175 	 * are both set in pci_vtnet_neg_features().
176 	 * Receive operation will be enabled again once the guest adds
177 	 * the first receive buffers and kicks us.
178 	 */
179 	netbe_rx_disable(sc->vsc_be);
180 
181 	/* Set sc->resetting and give a chance to the TX thread to stop. */
182 	pthread_mutex_lock(&sc->tx_mtx);
183 	sc->resetting = 1;
184 	while (sc->tx_in_progress) {
185 		pthread_mutex_unlock(&sc->tx_mtx);
186 		usleep(10000);
187 		pthread_mutex_lock(&sc->tx_mtx);
188 	}
189 
190 	/*
191 	 * Now reset rings, MSI-X vectors, and negotiated capabilities.
192 	 * Do that with the TX lock held, since we need to reset
193 	 * sc->resetting.
194 	 */
195 	vi_reset_dev(&sc->vsc_vs);
196 
197 	sc->resetting = 0;
198 	pthread_mutex_unlock(&sc->tx_mtx);
199 	pthread_mutex_unlock(&sc->rx_mtx);
200 }
201 
202 static __inline struct iovec *
203 iov_trim_hdr(struct iovec *iov, int *iovcnt, unsigned int hlen)
204 {
205 	struct iovec *riov;
206 
207 	if (iov[0].iov_len < hlen) {
208 		/*
209 		 * Not enough header space in the first fragment.
210 		 * That's not ok for us.
211 		 */
212 		return NULL;
213 	}
214 
215 	iov[0].iov_len -= hlen;
216 	if (iov[0].iov_len == 0) {
217 		*iovcnt -= 1;
218 		if (*iovcnt == 0) {
219 			/*
220 			 * Only space for the header. That's not
221 			 * enough for us.
222 			 */
223 			return NULL;
224 		}
225 		riov = &iov[1];
226 	} else {
227 		iov[0].iov_base = (void *)((uintptr_t)iov[0].iov_base + hlen);
228 		riov = &iov[0];
229 	}
230 
231 	return (riov);
232 }
233 
234 struct virtio_mrg_rxbuf_info {
235 	uint16_t idx;
236 	uint16_t pad;
237 	uint32_t len;
238 };
239 
240 static void
241 pci_vtnet_rx(struct pci_vtnet_softc *sc)
242 {
243 	int prepend_hdr_len = sc->vhdrlen - sc->be_vhdrlen;
244 	struct virtio_mrg_rxbuf_info info[VTNET_MAXSEGS];
245 	struct iovec iov[VTNET_MAXSEGS + 1];
246 	struct vqueue_info *vq;
247 
248 	vq = &sc->vsc_queues[VTNET_RXQ];
249 	for (;;) {
250 		struct virtio_net_rxhdr *hdr;
251 		uint32_t riov_bytes;
252 		struct iovec *riov;
253 		uint32_t ulen;
254 		int riov_len;
255 		int n_chains;
256 		ssize_t rlen;
257 		ssize_t plen;
258 
259 		plen = netbe_peek_recvlen(sc->vsc_be);
260 		if (plen <= 0) {
261 			/*
262 			 * No more packets (plen == 0), or backend errored
263 			 * (plen < 0). Interrupt if needed and stop.
264 			 */
265 			vq_endchains(vq, /*used_all_avail=*/0);
266 			return;
267 		}
268 		plen += prepend_hdr_len;
269 
270 		/*
271 		 * Get a descriptor chain to store the next ingress
272 		 * packet. In case of mergeable rx buffers, get as
273 		 * many chains as necessary in order to make room
274 		 * for plen bytes.
275 		 */
276 		riov_bytes = 0;
277 		riov_len = 0;
278 		riov = iov;
279 		n_chains = 0;
280 		do {
281 			int n = vq_getchain(vq, &info[n_chains].idx, riov,
282 			    VTNET_MAXSEGS - riov_len, NULL);
283 
284 			if (n == 0) {
285 				/*
286 				 * No rx buffers. Enable RX kicks and double
287 				 * check.
288 				 */
289 				vq_kick_enable(vq);
290 				if (!vq_has_descs(vq)) {
291 					/*
292 					 * Still no buffers. Return the unused
293 					 * chains (if any), interrupt if needed
294 					 * (including for NOTIFY_ON_EMPTY), and
295 					 * disable the backend until the next
296 					 * kick.
297 					 */
298 					vq_retchains(vq, n_chains);
299 					vq_endchains(vq, /*used_all_avail=*/1);
300 					netbe_rx_disable(sc->vsc_be);
301 					return;
302 				}
303 
304 				/* More rx buffers found, so keep going. */
305 				vq_kick_disable(vq);
306 				continue;
307 			}
308 			assert(n >= 1 && riov_len + n <= VTNET_MAXSEGS);
309 			riov_len += n;
310 			if (!sc->rx_merge) {
311 				n_chains = 1;
312 				break;
313 			}
314 			info[n_chains].len = (uint32_t)count_iov(riov, n);
315 			riov_bytes += info[n_chains].len;
316 			riov += n;
317 			n_chains++;
318 		} while (riov_bytes < plen && riov_len < VTNET_MAXSEGS);
319 
320 		riov = iov;
321 		hdr = riov[0].iov_base;
322 		if (prepend_hdr_len > 0) {
323 			/*
324 			 * The frontend uses a virtio-net header, but the
325 			 * backend does not. We need to prepend a zeroed
326 			 * header.
327 			 */
328 			riov = iov_trim_hdr(riov, &riov_len, prepend_hdr_len);
329 			if (riov == NULL) {
330 				/*
331 				 * The first collected chain is nonsensical,
332 				 * as it is not even enough to store the
333 				 * virtio-net header. Just drop it.
334 				 */
335 				vq_relchain(vq, info[0].idx, 0);
336 				vq_retchains(vq, n_chains - 1);
337 				continue;
338 			}
339 			memset(hdr, 0, prepend_hdr_len);
340 		}
341 
342 		rlen = netbe_recv(sc->vsc_be, riov, riov_len);
343 		if (rlen != plen - prepend_hdr_len) {
344 			/*
345 			 * If this happens it means there is something
346 			 * wrong with the backend (e.g., some other
347 			 * process is stealing our packets).
348 			 */
349 			WPRINTF(("netbe_recv: expected %zd bytes, "
350 				"got %zd", plen - prepend_hdr_len, rlen));
351 			vq_retchains(vq, n_chains);
352 			continue;
353 		}
354 
355 		ulen = (uint32_t)plen;
356 
357 		/*
358 		 * Publish the used buffers to the guest, reporting the
359 		 * number of bytes that we wrote.
360 		 */
361 		if (!sc->rx_merge) {
362 			vq_relchain(vq, info[0].idx, ulen);
363 		} else {
364 			uint32_t iolen;
365 			int i = 0;
366 
367 			do {
368 				iolen = info[i].len;
369 				if (iolen > ulen) {
370 					iolen = ulen;
371 				}
372 				vq_relchain_prepare(vq, info[i].idx, iolen);
373 				ulen -= iolen;
374 				i++;
375 			} while (ulen > 0);
376 
377 			hdr->vrh_bufs = i;
378 			vq_relchain_publish(vq);
379 			assert(i == n_chains);
380 		}
381 	}
382 
383 }
384 
385 /*
386  * Called when there is read activity on the backend file descriptor.
387  * Each buffer posted by the guest is assumed to be able to contain
388  * an entire ethernet frame + rx header.
389  */
390 static void
391 pci_vtnet_rx_callback(int fd, enum ev_type type, void *param)
392 {
393 	struct pci_vtnet_softc *sc = param;
394 
395 	pthread_mutex_lock(&sc->rx_mtx);
396 	pci_vtnet_rx(sc);
397 	pthread_mutex_unlock(&sc->rx_mtx);
398 
399 }
400 
401 /* Called on RX kick. */
402 static void
403 pci_vtnet_ping_rxq(void *vsc, struct vqueue_info *vq)
404 {
405 	struct pci_vtnet_softc *sc = vsc;
406 
407 	/*
408 	 * A qnotify means that the rx process can now begin.
409 	 */
410 	pthread_mutex_lock(&sc->rx_mtx);
411 	vq_kick_disable(vq);
412 	netbe_rx_enable(sc->vsc_be);
413 	pthread_mutex_unlock(&sc->rx_mtx);
414 }
415 
416 /* TX virtqueue processing, called by the TX thread. */
417 static void
418 pci_vtnet_proctx(struct pci_vtnet_softc *sc, struct vqueue_info *vq)
419 {
420 	struct iovec iov[VTNET_MAXSEGS + 1];
421 	struct iovec *siov = iov;
422 	uint16_t idx;
423 	ssize_t len;
424 	int n;
425 
426 	/*
427 	 * Obtain chain of descriptors. The first descriptor also
428 	 * contains the virtio-net header.
429 	 */
430 	n = vq_getchain(vq, &idx, iov, VTNET_MAXSEGS, NULL);
431 	assert(n >= 1 && n <= VTNET_MAXSEGS);
432 
433 	if (sc->vhdrlen != sc->be_vhdrlen) {
434 		/*
435 		 * The frontend uses a virtio-net header, but the backend
436 		 * does not. We simply strip the header and ignore it, as
437 		 * it should be zero-filled.
438 		 */
439 		siov = iov_trim_hdr(siov, &n, sc->vhdrlen);
440 	}
441 
442 	if (siov == NULL) {
443 		/* The chain is nonsensical. Just drop it. */
444 		len = 0;
445 	} else {
446 		len = netbe_send(sc->vsc_be, siov, n);
447 		if (len < 0) {
448 			/*
449 			 * If send failed, report that 0 bytes
450 			 * were read.
451 			 */
452 			len = 0;
453 		}
454 	}
455 
456 	/*
457 	 * Return the processed chain to the guest, reporting
458 	 * the number of bytes that we read.
459 	 */
460 	vq_relchain(vq, idx, len);
461 }
462 
463 /* Called on TX kick. */
464 static void
465 pci_vtnet_ping_txq(void *vsc, struct vqueue_info *vq)
466 {
467 	struct pci_vtnet_softc *sc = vsc;
468 
469 	/*
470 	 * Any ring entries to process?
471 	 */
472 	if (!vq_has_descs(vq))
473 		return;
474 
475 	/* Signal the tx thread for processing */
476 	pthread_mutex_lock(&sc->tx_mtx);
477 	vq_kick_disable(vq);
478 	if (sc->tx_in_progress == 0)
479 		pthread_cond_signal(&sc->tx_cond);
480 	pthread_mutex_unlock(&sc->tx_mtx);
481 }
482 
483 /*
484  * Thread which will handle processing of TX desc
485  */
486 static void *
487 pci_vtnet_tx_thread(void *param)
488 {
489 	struct pci_vtnet_softc *sc = param;
490 	struct vqueue_info *vq;
491 	int error;
492 
493 	vq = &sc->vsc_queues[VTNET_TXQ];
494 
495 	/*
496 	 * Let us wait till the tx queue pointers get initialised &
497 	 * first tx signaled
498 	 */
499 	pthread_mutex_lock(&sc->tx_mtx);
500 	error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx);
501 	assert(error == 0);
502 
503 	for (;;) {
504 		/* note - tx mutex is locked here */
505 		while (sc->resetting || !vq_has_descs(vq)) {
506 			vq_kick_enable(vq);
507 			if (!sc->resetting && vq_has_descs(vq))
508 				break;
509 
510 			sc->tx_in_progress = 0;
511 			error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx);
512 			assert(error == 0);
513 		}
514 		vq_kick_disable(vq);
515 		sc->tx_in_progress = 1;
516 		pthread_mutex_unlock(&sc->tx_mtx);
517 
518 		do {
519 			/*
520 			 * Run through entries, placing them into
521 			 * iovecs and sending when an end-of-packet
522 			 * is found
523 			 */
524 			pci_vtnet_proctx(sc, vq);
525 		} while (vq_has_descs(vq));
526 
527 		/*
528 		 * Generate an interrupt if needed.
529 		 */
530 		vq_endchains(vq, /*used_all_avail=*/1);
531 
532 		pthread_mutex_lock(&sc->tx_mtx);
533 	}
534 }
535 
536 #ifdef notyet
537 static void
538 pci_vtnet_ping_ctlq(void *vsc, struct vqueue_info *vq)
539 {
540 
541 	DPRINTF(("vtnet: control qnotify!"));
542 }
543 #endif
544 
545 static int
546 pci_vtnet_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
547 {
548 	struct pci_vtnet_softc *sc;
549 	char tname[MAXCOMLEN + 1];
550 	int mac_provided;
551 	int mtu_provided;
552 	unsigned long mtu = ETHERMTU;
553 
554 	/*
555 	 * Allocate data structures for further virtio initializations.
556 	 * sc also contains a copy of vtnet_vi_consts, since capabilities
557 	 * change depending on the backend.
558 	 */
559 	sc = calloc(1, sizeof(struct pci_vtnet_softc));
560 
561 	sc->vsc_consts = vtnet_vi_consts;
562 	pthread_mutex_init(&sc->vsc_mtx, NULL);
563 
564 	sc->vsc_queues[VTNET_RXQ].vq_qsize = VTNET_RINGSZ;
565 	sc->vsc_queues[VTNET_RXQ].vq_notify = pci_vtnet_ping_rxq;
566 	sc->vsc_queues[VTNET_TXQ].vq_qsize = VTNET_RINGSZ;
567 	sc->vsc_queues[VTNET_TXQ].vq_notify = pci_vtnet_ping_txq;
568 #ifdef notyet
569 	sc->vsc_queues[VTNET_CTLQ].vq_qsize = VTNET_RINGSZ;
570         sc->vsc_queues[VTNET_CTLQ].vq_notify = pci_vtnet_ping_ctlq;
571 #endif
572 
573 	/*
574 	 * Attempt to open the backend device and read the MAC address
575 	 * if specified.
576 	 */
577 	mac_provided = 0;
578 	mtu_provided = 0;
579 	if (opts != NULL) {
580 		char *optscopy;
581 		char *vtopts;
582 		int err = 0;
583 
584 		/* Get the device name. */
585 		optscopy = vtopts = strdup(opts);
586 		(void) strsep(&vtopts, ",");
587 
588 		/*
589 		 * Parse the list of options in the form
590 		 *     key1=value1,...,keyN=valueN.
591 		 */
592 		while (vtopts != NULL) {
593 			char *value = vtopts;
594 			char *key;
595 
596 			key = strsep(&value, "=");
597 			if (value == NULL)
598 				break;
599 			vtopts = value;
600 			(void) strsep(&vtopts, ",");
601 
602 			if (strcmp(key, "mac") == 0) {
603 				err = net_parsemac(value, sc->vsc_config.mac);
604 				if (err)
605 					break;
606 				mac_provided = 1;
607 			} else if (strcmp(key, "mtu") == 0) {
608 				err = net_parsemtu(value, &mtu);
609 				if (err)
610 					break;
611 
612 				if (mtu < VTNET_MIN_MTU || mtu > VTNET_MAX_MTU) {
613 					err = EINVAL;
614 					errno = EINVAL;
615 					break;
616 				}
617 				mtu_provided = 1;
618 			}
619 		}
620 
621 		free(optscopy);
622 
623 		if (err) {
624 			free(sc);
625 			return (err);
626 		}
627 
628 		err = netbe_init(&sc->vsc_be, opts, pci_vtnet_rx_callback,
629 		          sc);
630 
631 		if (err) {
632 			free(sc);
633 			return (err);
634 		}
635 		sc->vsc_consts.vc_hv_caps |= VIRTIO_NET_F_MRG_RXBUF |
636 		    netbe_get_cap(sc->vsc_be);
637 	}
638 
639 	if (!mac_provided) {
640 		net_genmac(pi, sc->vsc_config.mac);
641 	}
642 
643 	sc->vsc_config.mtu = mtu;
644 	if (mtu_provided) {
645 		sc->vsc_consts.vc_hv_caps |= VIRTIO_NET_F_MTU;
646 	}
647 
648 	/*
649 	 * Since we do not actually support multiqueue,
650 	 * set the maximum virtqueue pairs to 1.
651 	 */
652 	sc->vsc_config.max_virtqueue_pairs = 1;
653 
654 	/* initialize config space */
655 	pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_NET);
656 	pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
657 	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_NETWORK);
658 	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_NET);
659 	pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR);
660 
661 	/* Link is up if we managed to open backend device. */
662 	sc->vsc_config.status = (opts == NULL || sc->vsc_be);
663 
664 	vi_softc_linkup(&sc->vsc_vs, &sc->vsc_consts, sc, pi, sc->vsc_queues);
665 	sc->vsc_vs.vs_mtx = &sc->vsc_mtx;
666 
667 	/* use BAR 1 to map MSI-X table and PBA, if we're using MSI-X */
668 	if (vi_intr_init(&sc->vsc_vs, 1, fbsdrun_virtio_msix())) {
669 		free(sc);
670 		return (1);
671 	}
672 
673 	/* use BAR 0 to map config regs in IO space */
674 	vi_set_io_bar(&sc->vsc_vs, 0);
675 
676 	sc->resetting = 0;
677 
678 	sc->rx_merge = 0;
679 	sc->vhdrlen = sizeof(struct virtio_net_rxhdr) - 2;
680 	pthread_mutex_init(&sc->rx_mtx, NULL);
681 
682 	/*
683 	 * Initialize tx semaphore & spawn TX processing thread.
684 	 * As of now, only one thread for TX desc processing is
685 	 * spawned.
686 	 */
687 	sc->tx_in_progress = 0;
688 	pthread_mutex_init(&sc->tx_mtx, NULL);
689 	pthread_cond_init(&sc->tx_cond, NULL);
690 	pthread_create(&sc->tx_tid, NULL, pci_vtnet_tx_thread, (void *)sc);
691 	snprintf(tname, sizeof(tname), "vtnet-%d:%d tx", pi->pi_slot,
692 	    pi->pi_func);
693 	pthread_set_name_np(sc->tx_tid, tname);
694 
695 	return (0);
696 }
697 
698 static int
699 pci_vtnet_cfgwrite(void *vsc, int offset, int size, uint32_t value)
700 {
701 	struct pci_vtnet_softc *sc = vsc;
702 	void *ptr;
703 
704 	if (offset < (int)sizeof(sc->vsc_config.mac)) {
705 		assert(offset + size <= (int)sizeof(sc->vsc_config.mac));
706 		/*
707 		 * The driver is allowed to change the MAC address
708 		 */
709 		ptr = &sc->vsc_config.mac[offset];
710 		memcpy(ptr, &value, size);
711 	} else {
712 		/* silently ignore other writes */
713 		DPRINTF(("vtnet: write to readonly reg %d", offset));
714 	}
715 
716 	return (0);
717 }
718 
719 static int
720 pci_vtnet_cfgread(void *vsc, int offset, int size, uint32_t *retval)
721 {
722 	struct pci_vtnet_softc *sc = vsc;
723 	void *ptr;
724 
725 	ptr = (uint8_t *)&sc->vsc_config + offset;
726 	memcpy(retval, ptr, size);
727 	return (0);
728 }
729 
730 static void
731 pci_vtnet_neg_features(void *vsc, uint64_t negotiated_features)
732 {
733 	struct pci_vtnet_softc *sc = vsc;
734 
735 	sc->vsc_features = negotiated_features;
736 
737 	if (negotiated_features & VIRTIO_NET_F_MRG_RXBUF) {
738 		sc->vhdrlen = sizeof(struct virtio_net_rxhdr);
739 		sc->rx_merge = 1;
740 	} else {
741 		/*
742 		 * Without mergeable rx buffers, virtio-net header is 2
743 		 * bytes shorter than sizeof(struct virtio_net_rxhdr).
744 		 */
745 		sc->vhdrlen = sizeof(struct virtio_net_rxhdr) - 2;
746 		sc->rx_merge = 0;
747 	}
748 
749 	/* Tell the backend to enable some capabilities it has advertised. */
750 	netbe_set_cap(sc->vsc_be, negotiated_features, sc->vhdrlen);
751 	sc->be_vhdrlen = netbe_get_vnet_hdr_len(sc->vsc_be);
752 	assert(sc->be_vhdrlen == 0 || sc->be_vhdrlen == sc->vhdrlen);
753 }
754 
755 #ifdef BHYVE_SNAPSHOT
756 static void
757 pci_vtnet_pause(void *vsc)
758 {
759 	struct pci_vtnet_softc *sc = vsc;
760 
761 	DPRINTF(("vtnet: device pause requested !\n"));
762 
763 	/* Acquire the RX lock to block RX processing. */
764 	pthread_mutex_lock(&sc->rx_mtx);
765 
766 	/* Wait for the transmit thread to finish its processing. */
767 	pthread_mutex_lock(&sc->tx_mtx);
768 	while (sc->tx_in_progress) {
769 		pthread_mutex_unlock(&sc->tx_mtx);
770 		usleep(10000);
771 		pthread_mutex_lock(&sc->tx_mtx);
772 	}
773 }
774 
775 static void
776 pci_vtnet_resume(void *vsc)
777 {
778 	struct pci_vtnet_softc *sc = vsc;
779 
780 	DPRINTF(("vtnet: device resume requested !\n"));
781 
782 	pthread_mutex_unlock(&sc->tx_mtx);
783 	/* The RX lock should have been acquired in vtnet_pause. */
784 	pthread_mutex_unlock(&sc->rx_mtx);
785 }
786 
787 static int
788 pci_vtnet_snapshot(void *vsc, struct vm_snapshot_meta *meta)
789 {
790 	int ret;
791 	struct pci_vtnet_softc *sc = vsc;
792 
793 	DPRINTF(("vtnet: device snapshot requested !\n"));
794 
795 	/*
796 	 * Queues and consts should have been saved by the more generic
797 	 * vi_pci_snapshot function. We need to save only our features and
798 	 * config.
799 	 */
800 
801 	SNAPSHOT_VAR_OR_LEAVE(sc->vsc_features, meta, ret, done);
802 
803 	/* Force reapply negociated features at restore time */
804 	if (meta->op == VM_SNAPSHOT_RESTORE) {
805 		pci_vtnet_neg_features(sc, sc->vsc_features);
806 		netbe_rx_enable(sc->vsc_be);
807 	}
808 
809 	SNAPSHOT_VAR_OR_LEAVE(sc->vsc_config, meta, ret, done);
810 	SNAPSHOT_VAR_OR_LEAVE(sc->rx_merge, meta, ret, done);
811 
812 	SNAPSHOT_VAR_OR_LEAVE(sc->vhdrlen, meta, ret, done);
813 	SNAPSHOT_VAR_OR_LEAVE(sc->be_vhdrlen, meta, ret, done);
814 
815 done:
816 	return (ret);
817 }
818 #endif
819 
820 static struct pci_devemu pci_de_vnet = {
821 	.pe_emu = 	"virtio-net",
822 	.pe_init =	pci_vtnet_init,
823 	.pe_barwrite =	vi_pci_write,
824 	.pe_barread =	vi_pci_read,
825 #ifdef BHYVE_SNAPSHOT
826 	.pe_snapshot =	vi_pci_snapshot,
827 	.pe_pause =	vi_pci_pause,
828 	.pe_resume =	vi_pci_resume,
829 #endif
830 };
831 PCI_EMUL_SET(pci_de_vnet);
832