xref: /freebsd/usr.sbin/bhyve/pci_virtio_net.c (revision 39ee7a7a6bdd1557b1c3532abf60d139798ac88b)
1 /*-
2  * Copyright (c) 2011 NetApp, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/linker_set.h>
34 #include <sys/select.h>
35 #include <sys/uio.h>
36 #include <sys/ioctl.h>
37 #include <machine/atomic.h>
38 #include <net/ethernet.h>
39 
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <stdint.h>
45 #include <string.h>
46 #include <strings.h>
47 #include <unistd.h>
48 #include <assert.h>
49 #include <md5.h>
50 #include <pthread.h>
51 #include <pthread_np.h>
52 
53 #include "bhyverun.h"
54 #include "pci_emul.h"
55 #include "mevent.h"
56 #include "virtio.h"
57 
58 #define VTNET_RINGSZ	1024
59 
60 #define VTNET_MAXSEGS	256
61 
62 /*
63  * Host capabilities.  Note that we only offer a few of these.
64  */
65 #define	VIRTIO_NET_F_CSUM	(1 <<  0) /* host handles partial cksum */
66 #define	VIRTIO_NET_F_GUEST_CSUM	(1 <<  1) /* guest handles partial cksum */
67 #define	VIRTIO_NET_F_MAC	(1 <<  5) /* host supplies MAC */
68 #define	VIRTIO_NET_F_GSO_DEPREC	(1 <<  6) /* deprecated: host handles GSO */
69 #define	VIRTIO_NET_F_GUEST_TSO4	(1 <<  7) /* guest can rcv TSOv4 */
70 #define	VIRTIO_NET_F_GUEST_TSO6	(1 <<  8) /* guest can rcv TSOv6 */
71 #define	VIRTIO_NET_F_GUEST_ECN	(1 <<  9) /* guest can rcv TSO with ECN */
72 #define	VIRTIO_NET_F_GUEST_UFO	(1 << 10) /* guest can rcv UFO */
73 #define	VIRTIO_NET_F_HOST_TSO4	(1 << 11) /* host can rcv TSOv4 */
74 #define	VIRTIO_NET_F_HOST_TSO6	(1 << 12) /* host can rcv TSOv6 */
75 #define	VIRTIO_NET_F_HOST_ECN	(1 << 13) /* host can rcv TSO with ECN */
76 #define	VIRTIO_NET_F_HOST_UFO	(1 << 14) /* host can rcv UFO */
77 #define	VIRTIO_NET_F_MRG_RXBUF	(1 << 15) /* host can merge RX buffers */
78 #define	VIRTIO_NET_F_STATUS	(1 << 16) /* config status field available */
79 #define	VIRTIO_NET_F_CTRL_VQ	(1 << 17) /* control channel available */
80 #define	VIRTIO_NET_F_CTRL_RX	(1 << 18) /* control channel RX mode support */
81 #define	VIRTIO_NET_F_CTRL_VLAN	(1 << 19) /* control channel VLAN filtering */
82 #define	VIRTIO_NET_F_GUEST_ANNOUNCE \
83 				(1 << 21) /* guest can send gratuitous pkts */
84 
85 #define VTNET_S_HOSTCAPS      \
86   ( VIRTIO_NET_F_MAC | VIRTIO_NET_F_MRG_RXBUF | VIRTIO_NET_F_STATUS | \
87     VIRTIO_F_NOTIFY_ON_EMPTY | VIRTIO_RING_F_INDIRECT_DESC)
88 
89 /*
90  * PCI config-space "registers"
91  */
92 struct virtio_net_config {
93 	uint8_t  mac[6];
94 	uint16_t status;
95 } __packed;
96 
97 /*
98  * Queue definitions.
99  */
100 #define VTNET_RXQ	0
101 #define VTNET_TXQ	1
102 #define VTNET_CTLQ	2	/* NB: not yet supported */
103 
104 #define VTNET_MAXQ	3
105 
106 /*
107  * Fixed network header size
108  */
109 struct virtio_net_rxhdr {
110 	uint8_t		vrh_flags;
111 	uint8_t		vrh_gso_type;
112 	uint16_t	vrh_hdr_len;
113 	uint16_t	vrh_gso_size;
114 	uint16_t	vrh_csum_start;
115 	uint16_t	vrh_csum_offset;
116 	uint16_t	vrh_bufs;
117 } __packed;
118 
119 /*
120  * Debug printf
121  */
122 static int pci_vtnet_debug;
123 #define DPRINTF(params) if (pci_vtnet_debug) printf params
124 #define WPRINTF(params) printf params
125 
126 /*
127  * Per-device softc
128  */
129 struct pci_vtnet_softc {
130 	struct virtio_softc vsc_vs;
131 	struct vqueue_info vsc_queues[VTNET_MAXQ - 1];
132 	pthread_mutex_t vsc_mtx;
133 	struct mevent	*vsc_mevp;
134 
135 	int		vsc_tapfd;
136 	int		vsc_rx_ready;
137 	volatile int	resetting;	/* set and checked outside lock */
138 
139 	uint64_t	vsc_features;	/* negotiated features */
140 
141 	struct virtio_net_config vsc_config;
142 
143 	pthread_mutex_t	rx_mtx;
144 	int		rx_in_progress;
145 	int		rx_vhdrlen;
146 	int		rx_merge;	/* merged rx bufs in use */
147 
148 	pthread_t 	tx_tid;
149 	pthread_mutex_t	tx_mtx;
150 	pthread_cond_t	tx_cond;
151 	int		tx_in_progress;
152 };
153 
154 static void pci_vtnet_reset(void *);
155 /* static void pci_vtnet_notify(void *, struct vqueue_info *); */
156 static int pci_vtnet_cfgread(void *, int, int, uint32_t *);
157 static int pci_vtnet_cfgwrite(void *, int, int, uint32_t);
158 static void pci_vtnet_neg_features(void *, uint64_t);
159 
160 static struct virtio_consts vtnet_vi_consts = {
161 	"vtnet",		/* our name */
162 	VTNET_MAXQ - 1,		/* we currently support 2 virtqueues */
163 	sizeof(struct virtio_net_config), /* config reg size */
164 	pci_vtnet_reset,	/* reset */
165 	NULL,			/* device-wide qnotify -- not used */
166 	pci_vtnet_cfgread,	/* read PCI config */
167 	pci_vtnet_cfgwrite,	/* write PCI config */
168 	pci_vtnet_neg_features,	/* apply negotiated features */
169 	VTNET_S_HOSTCAPS,	/* our capabilities */
170 };
171 
172 /*
173  * If the transmit thread is active then stall until it is done.
174  */
175 static void
176 pci_vtnet_txwait(struct pci_vtnet_softc *sc)
177 {
178 
179 	pthread_mutex_lock(&sc->tx_mtx);
180 	while (sc->tx_in_progress) {
181 		pthread_mutex_unlock(&sc->tx_mtx);
182 		usleep(10000);
183 		pthread_mutex_lock(&sc->tx_mtx);
184 	}
185 	pthread_mutex_unlock(&sc->tx_mtx);
186 }
187 
188 /*
189  * If the receive thread is active then stall until it is done.
190  */
191 static void
192 pci_vtnet_rxwait(struct pci_vtnet_softc *sc)
193 {
194 
195 	pthread_mutex_lock(&sc->rx_mtx);
196 	while (sc->rx_in_progress) {
197 		pthread_mutex_unlock(&sc->rx_mtx);
198 		usleep(10000);
199 		pthread_mutex_lock(&sc->rx_mtx);
200 	}
201 	pthread_mutex_unlock(&sc->rx_mtx);
202 }
203 
204 static void
205 pci_vtnet_reset(void *vsc)
206 {
207 	struct pci_vtnet_softc *sc = vsc;
208 
209 	DPRINTF(("vtnet: device reset requested !\n"));
210 
211 	sc->resetting = 1;
212 
213 	/*
214 	 * Wait for the transmit and receive threads to finish their
215 	 * processing.
216 	 */
217 	pci_vtnet_txwait(sc);
218 	pci_vtnet_rxwait(sc);
219 
220 	sc->vsc_rx_ready = 0;
221 	sc->rx_merge = 1;
222 	sc->rx_vhdrlen = sizeof(struct virtio_net_rxhdr);
223 
224 	/* now reset rings, MSI-X vectors, and negotiated capabilities */
225 	vi_reset_dev(&sc->vsc_vs);
226 
227 	sc->resetting = 0;
228 }
229 
230 /*
231  * Called to send a buffer chain out to the tap device
232  */
233 static void
234 pci_vtnet_tap_tx(struct pci_vtnet_softc *sc, struct iovec *iov, int iovcnt,
235 		 int len)
236 {
237 	static char pad[60]; /* all zero bytes */
238 
239 	if (sc->vsc_tapfd == -1)
240 		return;
241 
242 	/*
243 	 * If the length is < 60, pad out to that and add the
244 	 * extra zero'd segment to the iov. It is guaranteed that
245 	 * there is always an extra iov available by the caller.
246 	 */
247 	if (len < 60) {
248 		iov[iovcnt].iov_base = pad;
249 		iov[iovcnt].iov_len = 60 - len;
250 		iovcnt++;
251 	}
252 	(void) writev(sc->vsc_tapfd, iov, iovcnt);
253 }
254 
255 /*
256  *  Called when there is read activity on the tap file descriptor.
257  * Each buffer posted by the guest is assumed to be able to contain
258  * an entire ethernet frame + rx header.
259  *  MP note: the dummybuf is only used for discarding frames, so there
260  * is no need for it to be per-vtnet or locked.
261  */
262 static uint8_t dummybuf[2048];
263 
264 static __inline struct iovec *
265 rx_iov_trim(struct iovec *iov, int *niov, int tlen)
266 {
267 	struct iovec *riov;
268 
269 	/* XXX short-cut: assume first segment is >= tlen */
270 	assert(iov[0].iov_len >= tlen);
271 
272 	iov[0].iov_len -= tlen;
273 	if (iov[0].iov_len == 0) {
274 		assert(*niov > 1);
275 		*niov -= 1;
276 		riov = &iov[1];
277 	} else {
278 		iov[0].iov_base = (void *)((uintptr_t)iov[0].iov_base + tlen);
279 		riov = &iov[0];
280 	}
281 
282 	return (riov);
283 }
284 
285 static void
286 pci_vtnet_tap_rx(struct pci_vtnet_softc *sc)
287 {
288 	struct iovec iov[VTNET_MAXSEGS], *riov;
289 	struct vqueue_info *vq;
290 	void *vrx;
291 	int len, n;
292 	uint16_t idx;
293 
294 	/*
295 	 * Should never be called without a valid tap fd
296 	 */
297 	assert(sc->vsc_tapfd != -1);
298 
299 	/*
300 	 * But, will be called when the rx ring hasn't yet
301 	 * been set up or the guest is resetting the device.
302 	 */
303 	if (!sc->vsc_rx_ready || sc->resetting) {
304 		/*
305 		 * Drop the packet and try later.
306 		 */
307 		(void) read(sc->vsc_tapfd, dummybuf, sizeof(dummybuf));
308 		return;
309 	}
310 
311 	/*
312 	 * Check for available rx buffers
313 	 */
314 	vq = &sc->vsc_queues[VTNET_RXQ];
315 	if (!vq_has_descs(vq)) {
316 		/*
317 		 * Drop the packet and try later.  Interrupt on
318 		 * empty, if that's negotiated.
319 		 */
320 		(void) read(sc->vsc_tapfd, dummybuf, sizeof(dummybuf));
321 		vq_endchains(vq, 1);
322 		return;
323 	}
324 
325 	do {
326 		/*
327 		 * Get descriptor chain.
328 		 */
329 		n = vq_getchain(vq, &idx, iov, VTNET_MAXSEGS, NULL);
330 		assert(n >= 1 && n <= VTNET_MAXSEGS);
331 
332 		/*
333 		 * Get a pointer to the rx header, and use the
334 		 * data immediately following it for the packet buffer.
335 		 */
336 		vrx = iov[0].iov_base;
337 		riov = rx_iov_trim(iov, &n, sc->rx_vhdrlen);
338 
339 		len = readv(sc->vsc_tapfd, riov, n);
340 
341 		if (len < 0 && errno == EWOULDBLOCK) {
342 			/*
343 			 * No more packets, but still some avail ring
344 			 * entries.  Interrupt if needed/appropriate.
345 			 */
346 			vq_retchain(vq);
347 			vq_endchains(vq, 0);
348 			return;
349 		}
350 
351 		/*
352 		 * The only valid field in the rx packet header is the
353 		 * number of buffers if merged rx bufs were negotiated.
354 		 */
355 		memset(vrx, 0, sc->rx_vhdrlen);
356 
357 		if (sc->rx_merge) {
358 			struct virtio_net_rxhdr *vrxh;
359 
360 			vrxh = vrx;
361 			vrxh->vrh_bufs = 1;
362 		}
363 
364 		/*
365 		 * Release this chain and handle more chains.
366 		 */
367 		vq_relchain(vq, idx, len + sc->rx_vhdrlen);
368 	} while (vq_has_descs(vq));
369 
370 	/* Interrupt if needed, including for NOTIFY_ON_EMPTY. */
371 	vq_endchains(vq, 1);
372 }
373 
374 static void
375 pci_vtnet_tap_callback(int fd, enum ev_type type, void *param)
376 {
377 	struct pci_vtnet_softc *sc = param;
378 
379 	pthread_mutex_lock(&sc->rx_mtx);
380 	sc->rx_in_progress = 1;
381 	pci_vtnet_tap_rx(sc);
382 	sc->rx_in_progress = 0;
383 	pthread_mutex_unlock(&sc->rx_mtx);
384 
385 }
386 
387 static void
388 pci_vtnet_ping_rxq(void *vsc, struct vqueue_info *vq)
389 {
390 	struct pci_vtnet_softc *sc = vsc;
391 
392 	/*
393 	 * A qnotify means that the rx process can now begin
394 	 */
395 	if (sc->vsc_rx_ready == 0) {
396 		sc->vsc_rx_ready = 1;
397 		vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
398 	}
399 }
400 
401 static void
402 pci_vtnet_proctx(struct pci_vtnet_softc *sc, struct vqueue_info *vq)
403 {
404 	struct iovec iov[VTNET_MAXSEGS + 1];
405 	int i, n;
406 	int plen, tlen;
407 	uint16_t idx;
408 
409 	/*
410 	 * Obtain chain of descriptors.  The first one is
411 	 * really the header descriptor, so we need to sum
412 	 * up two lengths: packet length and transfer length.
413 	 */
414 	n = vq_getchain(vq, &idx, iov, VTNET_MAXSEGS, NULL);
415 	assert(n >= 1 && n <= VTNET_MAXSEGS);
416 	plen = 0;
417 	tlen = iov[0].iov_len;
418 	for (i = 1; i < n; i++) {
419 		plen += iov[i].iov_len;
420 		tlen += iov[i].iov_len;
421 	}
422 
423 	DPRINTF(("virtio: packet send, %d bytes, %d segs\n\r", plen, n));
424 	pci_vtnet_tap_tx(sc, &iov[1], n - 1, plen);
425 
426 	/* chain is processed, release it and set tlen */
427 	vq_relchain(vq, idx, tlen);
428 }
429 
430 static void
431 pci_vtnet_ping_txq(void *vsc, struct vqueue_info *vq)
432 {
433 	struct pci_vtnet_softc *sc = vsc;
434 
435 	/*
436 	 * Any ring entries to process?
437 	 */
438 	if (!vq_has_descs(vq))
439 		return;
440 
441 	/* Signal the tx thread for processing */
442 	pthread_mutex_lock(&sc->tx_mtx);
443 	vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
444 	if (sc->tx_in_progress == 0)
445 		pthread_cond_signal(&sc->tx_cond);
446 	pthread_mutex_unlock(&sc->tx_mtx);
447 }
448 
449 /*
450  * Thread which will handle processing of TX desc
451  */
452 static void *
453 pci_vtnet_tx_thread(void *param)
454 {
455 	struct pci_vtnet_softc *sc = param;
456 	struct vqueue_info *vq;
457 	int error;
458 
459 	vq = &sc->vsc_queues[VTNET_TXQ];
460 
461 	/*
462 	 * Let us wait till the tx queue pointers get initialised &
463 	 * first tx signaled
464 	 */
465 	pthread_mutex_lock(&sc->tx_mtx);
466 	error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx);
467 	assert(error == 0);
468 
469 	for (;;) {
470 		/* note - tx mutex is locked here */
471 		while (sc->resetting || !vq_has_descs(vq)) {
472 			vq->vq_used->vu_flags &= ~VRING_USED_F_NO_NOTIFY;
473 			mb();
474 			if (!sc->resetting && vq_has_descs(vq))
475 				break;
476 
477 			sc->tx_in_progress = 0;
478 			error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx);
479 			assert(error == 0);
480 		}
481 		vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
482 		sc->tx_in_progress = 1;
483 		pthread_mutex_unlock(&sc->tx_mtx);
484 
485 		do {
486 			/*
487 			 * Run through entries, placing them into
488 			 * iovecs and sending when an end-of-packet
489 			 * is found
490 			 */
491 			pci_vtnet_proctx(sc, vq);
492 		} while (vq_has_descs(vq));
493 
494 		/*
495 		 * Generate an interrupt if needed.
496 		 */
497 		vq_endchains(vq, 1);
498 
499 		pthread_mutex_lock(&sc->tx_mtx);
500 	}
501 }
502 
503 #ifdef notyet
504 static void
505 pci_vtnet_ping_ctlq(void *vsc, struct vqueue_info *vq)
506 {
507 
508 	DPRINTF(("vtnet: control qnotify!\n\r"));
509 }
510 #endif
511 
512 static int
513 pci_vtnet_parsemac(char *mac_str, uint8_t *mac_addr)
514 {
515         struct ether_addr *ea;
516         char *tmpstr;
517         char zero_addr[ETHER_ADDR_LEN] = { 0, 0, 0, 0, 0, 0 };
518 
519         tmpstr = strsep(&mac_str,"=");
520 
521         if ((mac_str != NULL) && (!strcmp(tmpstr,"mac"))) {
522                 ea = ether_aton(mac_str);
523 
524                 if (ea == NULL || ETHER_IS_MULTICAST(ea->octet) ||
525                     memcmp(ea->octet, zero_addr, ETHER_ADDR_LEN) == 0) {
526 			fprintf(stderr, "Invalid MAC %s\n", mac_str);
527                         return (EINVAL);
528                 } else
529                         memcpy(mac_addr, ea->octet, ETHER_ADDR_LEN);
530         }
531 
532         return (0);
533 }
534 
535 
536 static int
537 pci_vtnet_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
538 {
539 	MD5_CTX mdctx;
540 	unsigned char digest[16];
541 	char nstr[80];
542 	char tname[MAXCOMLEN + 1];
543 	struct pci_vtnet_softc *sc;
544 	char *devname;
545 	char *vtopts;
546 	int mac_provided;
547 
548 	sc = calloc(1, sizeof(struct pci_vtnet_softc));
549 
550 	pthread_mutex_init(&sc->vsc_mtx, NULL);
551 
552 	vi_softc_linkup(&sc->vsc_vs, &vtnet_vi_consts, sc, pi, sc->vsc_queues);
553 	sc->vsc_vs.vs_mtx = &sc->vsc_mtx;
554 
555 	sc->vsc_queues[VTNET_RXQ].vq_qsize = VTNET_RINGSZ;
556 	sc->vsc_queues[VTNET_RXQ].vq_notify = pci_vtnet_ping_rxq;
557 	sc->vsc_queues[VTNET_TXQ].vq_qsize = VTNET_RINGSZ;
558 	sc->vsc_queues[VTNET_TXQ].vq_notify = pci_vtnet_ping_txq;
559 #ifdef notyet
560 	sc->vsc_queues[VTNET_CTLQ].vq_qsize = VTNET_RINGSZ;
561         sc->vsc_queues[VTNET_CTLQ].vq_notify = pci_vtnet_ping_ctlq;
562 #endif
563 
564 	/*
565 	 * Attempt to open the tap device and read the MAC address
566 	 * if specified
567 	 */
568 	mac_provided = 0;
569 	sc->vsc_tapfd = -1;
570 	if (opts != NULL) {
571 		char tbuf[80];
572 		int err;
573 
574 		devname = vtopts = strdup(opts);
575 		(void) strsep(&vtopts, ",");
576 
577 		if (vtopts != NULL) {
578 			err = pci_vtnet_parsemac(vtopts, sc->vsc_config.mac);
579 			if (err != 0) {
580 				free(devname);
581 				return (err);
582 			}
583 			mac_provided = 1;
584 		}
585 
586 		strcpy(tbuf, "/dev/");
587 		strlcat(tbuf, devname, sizeof(tbuf));
588 
589 		free(devname);
590 
591 		sc->vsc_tapfd = open(tbuf, O_RDWR);
592 		if (sc->vsc_tapfd == -1) {
593 			WPRINTF(("open of tap device %s failed\n", tbuf));
594 		} else {
595 			/*
596 			 * Set non-blocking and register for read
597 			 * notifications with the event loop
598 			 */
599 			int opt = 1;
600 			if (ioctl(sc->vsc_tapfd, FIONBIO, &opt) < 0) {
601 				WPRINTF(("tap device O_NONBLOCK failed\n"));
602 				close(sc->vsc_tapfd);
603 				sc->vsc_tapfd = -1;
604 			}
605 
606 			sc->vsc_mevp = mevent_add(sc->vsc_tapfd,
607 						  EVF_READ,
608 						  pci_vtnet_tap_callback,
609 						  sc);
610 			if (sc->vsc_mevp == NULL) {
611 				WPRINTF(("Could not register event\n"));
612 				close(sc->vsc_tapfd);
613 				sc->vsc_tapfd = -1;
614 			}
615 		}
616 	}
617 
618 	/*
619 	 * The default MAC address is the standard NetApp OUI of 00-a0-98,
620 	 * followed by an MD5 of the PCI slot/func number and dev name
621 	 */
622 	if (!mac_provided) {
623 		snprintf(nstr, sizeof(nstr), "%d-%d-%s", pi->pi_slot,
624 		    pi->pi_func, vmname);
625 
626 		MD5Init(&mdctx);
627 		MD5Update(&mdctx, nstr, strlen(nstr));
628 		MD5Final(digest, &mdctx);
629 
630 		sc->vsc_config.mac[0] = 0x00;
631 		sc->vsc_config.mac[1] = 0xa0;
632 		sc->vsc_config.mac[2] = 0x98;
633 		sc->vsc_config.mac[3] = digest[0];
634 		sc->vsc_config.mac[4] = digest[1];
635 		sc->vsc_config.mac[5] = digest[2];
636 	}
637 
638 	/* initialize config space */
639 	pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_NET);
640 	pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
641 	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_NETWORK);
642 	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_NET);
643 	pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR);
644 
645 	/* Link is up if we managed to open tap device. */
646 	sc->vsc_config.status = (opts == NULL || sc->vsc_tapfd >= 0);
647 
648 	/* use BAR 1 to map MSI-X table and PBA, if we're using MSI-X */
649 	if (vi_intr_init(&sc->vsc_vs, 1, fbsdrun_virtio_msix()))
650 		return (1);
651 
652 	/* use BAR 0 to map config regs in IO space */
653 	vi_set_io_bar(&sc->vsc_vs, 0);
654 
655 	sc->resetting = 0;
656 
657 	sc->rx_merge = 1;
658 	sc->rx_vhdrlen = sizeof(struct virtio_net_rxhdr);
659 	sc->rx_in_progress = 0;
660 	pthread_mutex_init(&sc->rx_mtx, NULL);
661 
662 	/*
663 	 * Initialize tx semaphore & spawn TX processing thread.
664 	 * As of now, only one thread for TX desc processing is
665 	 * spawned.
666 	 */
667 	sc->tx_in_progress = 0;
668 	pthread_mutex_init(&sc->tx_mtx, NULL);
669 	pthread_cond_init(&sc->tx_cond, NULL);
670 	pthread_create(&sc->tx_tid, NULL, pci_vtnet_tx_thread, (void *)sc);
671 	snprintf(tname, sizeof(tname), "vtnet-%d:%d tx", pi->pi_slot,
672 	    pi->pi_func);
673         pthread_set_name_np(sc->tx_tid, tname);
674 
675 	return (0);
676 }
677 
678 static int
679 pci_vtnet_cfgwrite(void *vsc, int offset, int size, uint32_t value)
680 {
681 	struct pci_vtnet_softc *sc = vsc;
682 	void *ptr;
683 
684 	if (offset < 6) {
685 		assert(offset + size <= 6);
686 		/*
687 		 * The driver is allowed to change the MAC address
688 		 */
689 		ptr = &sc->vsc_config.mac[offset];
690 		memcpy(ptr, &value, size);
691 	} else {
692 		/* silently ignore other writes */
693 		DPRINTF(("vtnet: write to readonly reg %d\n\r", offset));
694 	}
695 
696 	return (0);
697 }
698 
699 static int
700 pci_vtnet_cfgread(void *vsc, int offset, int size, uint32_t *retval)
701 {
702 	struct pci_vtnet_softc *sc = vsc;
703 	void *ptr;
704 
705 	ptr = (uint8_t *)&sc->vsc_config + offset;
706 	memcpy(retval, ptr, size);
707 	return (0);
708 }
709 
710 static void
711 pci_vtnet_neg_features(void *vsc, uint64_t negotiated_features)
712 {
713 	struct pci_vtnet_softc *sc = vsc;
714 
715 	sc->vsc_features = negotiated_features;
716 
717 	if (!(sc->vsc_features & VIRTIO_NET_F_MRG_RXBUF)) {
718 		sc->rx_merge = 0;
719 		/* non-merge rx header is 2 bytes shorter */
720 		sc->rx_vhdrlen -= 2;
721 	}
722 }
723 
724 struct pci_devemu pci_de_vnet = {
725 	.pe_emu = 	"virtio-net",
726 	.pe_init =	pci_vtnet_init,
727 	.pe_barwrite =	vi_pci_write,
728 	.pe_barread =	vi_pci_read
729 };
730 PCI_EMUL_SET(pci_de_vnet);
731