xref: /freebsd/sys/dev/virtio/pci/virtio_pci.c (revision 63a938566d524836885917d95bd491aa4400b181)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org>
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 unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /* Driver for the VirtIO PCI interface. */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/bus.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 #include <sys/malloc.h>
40 
41 #include <machine/bus.h>
42 #include <machine/resource.h>
43 #include <sys/bus.h>
44 #include <sys/rman.h>
45 
46 #include <dev/pci/pcivar.h>
47 #include <dev/pci/pcireg.h>
48 
49 #include <dev/virtio/virtio.h>
50 #include <dev/virtio/virtqueue.h>
51 #include <dev/virtio/pci/virtio_pci.h>
52 
53 #include "virtio_bus_if.h"
54 #include "virtio_if.h"
55 
56 struct vtpci_interrupt {
57 	struct resource		*vti_irq;
58 	int			 vti_rid;
59 	void			*vti_handler;
60 };
61 
62 struct vtpci_virtqueue {
63 	struct virtqueue	*vtv_vq;
64 	int			 vtv_no_intr;
65 };
66 
67 struct vtpci_softc {
68 	device_t			 vtpci_dev;
69 	struct resource			*vtpci_res;
70 	struct resource			*vtpci_msix_res;
71 	uint64_t			 vtpci_features;
72 	uint32_t			 vtpci_flags;
73 #define VTPCI_FLAG_NO_MSI		0x0001
74 #define VTPCI_FLAG_NO_MSIX		0x0002
75 #define VTPCI_FLAG_LEGACY		0x1000
76 #define VTPCI_FLAG_MSI			0x2000
77 #define VTPCI_FLAG_MSIX			0x4000
78 #define VTPCI_FLAG_SHARED_MSIX		0x8000
79 #define VTPCI_FLAG_ITYPE_MASK		0xF000
80 
81 	/* This "bus" will only ever have one child. */
82 	device_t			 vtpci_child_dev;
83 	struct virtio_feature_desc	*vtpci_child_feat_desc;
84 
85 	int				 vtpci_nvqs;
86 	struct vtpci_virtqueue		*vtpci_vqs;
87 
88 	/*
89 	 * Ideally, each virtqueue that the driver provides a callback for will
90 	 * receive its own MSIX vector. If there are not sufficient vectors
91 	 * available, then attempt to have all the VQs share one vector. For
92 	 * MSIX, the configuration changed notifications must be on their own
93 	 * vector.
94 	 *
95 	 * If MSIX is not available, we will attempt to have the whole device
96 	 * share one MSI vector, and then, finally, one legacy interrupt.
97 	 */
98 	struct vtpci_interrupt		 vtpci_device_interrupt;
99 	struct vtpci_interrupt		*vtpci_msix_vq_interrupts;
100 	int				 vtpci_nmsix_resources;
101 };
102 
103 static int	vtpci_probe(device_t);
104 static int	vtpci_attach(device_t);
105 static int	vtpci_detach(device_t);
106 static int	vtpci_suspend(device_t);
107 static int	vtpci_resume(device_t);
108 static int	vtpci_shutdown(device_t);
109 static void	vtpci_driver_added(device_t, driver_t *);
110 static void	vtpci_child_detached(device_t, device_t);
111 static int	vtpci_read_ivar(device_t, device_t, int, uintptr_t *);
112 static int	vtpci_write_ivar(device_t, device_t, int, uintptr_t);
113 
114 static uint64_t	vtpci_negotiate_features(device_t, uint64_t);
115 static int	vtpci_with_feature(device_t, uint64_t);
116 static int	vtpci_alloc_virtqueues(device_t, int, int,
117 		    struct vq_alloc_info *);
118 static int	vtpci_setup_intr(device_t, enum intr_type);
119 static void	vtpci_stop(device_t);
120 static int	vtpci_reinit(device_t, uint64_t);
121 static void	vtpci_reinit_complete(device_t);
122 static void	vtpci_notify_virtqueue(device_t, uint16_t);
123 static uint8_t	vtpci_get_status(device_t);
124 static void	vtpci_set_status(device_t, uint8_t);
125 static void	vtpci_read_dev_config(device_t, bus_size_t, void *, int);
126 static void	vtpci_write_dev_config(device_t, bus_size_t, void *, int);
127 
128 static void	vtpci_describe_features(struct vtpci_softc *, const char *,
129 		    uint64_t);
130 static void	vtpci_probe_and_attach_child(struct vtpci_softc *);
131 
132 static int	vtpci_alloc_msix(struct vtpci_softc *, int);
133 static int	vtpci_alloc_msi(struct vtpci_softc *);
134 static int	vtpci_alloc_intr_msix_pervq(struct vtpci_softc *);
135 static int	vtpci_alloc_intr_msix_shared(struct vtpci_softc *);
136 static int	vtpci_alloc_intr_msi(struct vtpci_softc *);
137 static int	vtpci_alloc_intr_legacy(struct vtpci_softc *);
138 static int	vtpci_alloc_interrupt(struct vtpci_softc *, int, int,
139 		    struct vtpci_interrupt *);
140 static int	vtpci_alloc_intr_resources(struct vtpci_softc *);
141 
142 static int	vtpci_setup_legacy_interrupt(struct vtpci_softc *,
143 		    enum intr_type);
144 static int	vtpci_setup_pervq_msix_interrupts(struct vtpci_softc *,
145 		    enum intr_type);
146 static int	vtpci_setup_msix_interrupts(struct vtpci_softc *,
147 		    enum intr_type);
148 static int	vtpci_setup_interrupts(struct vtpci_softc *, enum intr_type);
149 
150 static int	vtpci_register_msix_vector(struct vtpci_softc *, int,
151 		    struct vtpci_interrupt *);
152 static int	vtpci_set_host_msix_vectors(struct vtpci_softc *);
153 static int	vtpci_reinit_virtqueue(struct vtpci_softc *, int);
154 
155 static void	vtpci_free_interrupt(struct vtpci_softc *,
156 		    struct vtpci_interrupt *);
157 static void	vtpci_free_interrupts(struct vtpci_softc *);
158 static void	vtpci_free_virtqueues(struct vtpci_softc *);
159 static void	vtpci_release_child_resources(struct vtpci_softc *);
160 static void	vtpci_cleanup_setup_intr_attempt(struct vtpci_softc *);
161 static void	vtpci_reset(struct vtpci_softc *);
162 
163 static void	vtpci_select_virtqueue(struct vtpci_softc *, int);
164 
165 static void	vtpci_legacy_intr(void *);
166 static int	vtpci_vq_shared_intr_filter(void *);
167 static void	vtpci_vq_shared_intr(void *);
168 static int	vtpci_vq_intr_filter(void *);
169 static void	vtpci_vq_intr(void *);
170 static void	vtpci_config_intr(void *);
171 
172 #define vtpci_setup_msi_interrupt vtpci_setup_legacy_interrupt
173 
174 #define VIRTIO_PCI_CONFIG(_sc) \
175     VIRTIO_PCI_CONFIG_OFF((((_sc)->vtpci_flags & VTPCI_FLAG_MSIX)) != 0)
176 
177 /*
178  * I/O port read/write wrappers.
179  */
180 #define vtpci_read_config_1(sc, o)	bus_read_1((sc)->vtpci_res, (o))
181 #define vtpci_read_config_2(sc, o)	bus_read_2((sc)->vtpci_res, (o))
182 #define vtpci_read_config_4(sc, o)	bus_read_4((sc)->vtpci_res, (o))
183 #define vtpci_write_config_1(sc, o, v)	bus_write_1((sc)->vtpci_res, (o), (v))
184 #define vtpci_write_config_2(sc, o, v)	bus_write_2((sc)->vtpci_res, (o), (v))
185 #define vtpci_write_config_4(sc, o, v)	bus_write_4((sc)->vtpci_res, (o), (v))
186 
187 /* Tunables. */
188 static int vtpci_disable_msix = 0;
189 TUNABLE_INT("hw.virtio.pci.disable_msix", &vtpci_disable_msix);
190 
191 static device_method_t vtpci_methods[] = {
192 	/* Device interface. */
193 	DEVMETHOD(device_probe,			  vtpci_probe),
194 	DEVMETHOD(device_attach,		  vtpci_attach),
195 	DEVMETHOD(device_detach,		  vtpci_detach),
196 	DEVMETHOD(device_suspend,		  vtpci_suspend),
197 	DEVMETHOD(device_resume,		  vtpci_resume),
198 	DEVMETHOD(device_shutdown,		  vtpci_shutdown),
199 
200 	/* Bus interface. */
201 	DEVMETHOD(bus_driver_added,		  vtpci_driver_added),
202 	DEVMETHOD(bus_child_detached,		  vtpci_child_detached),
203 	DEVMETHOD(bus_read_ivar,		  vtpci_read_ivar),
204 	DEVMETHOD(bus_write_ivar,		  vtpci_write_ivar),
205 
206 	/* VirtIO bus interface. */
207 	DEVMETHOD(virtio_bus_negotiate_features,  vtpci_negotiate_features),
208 	DEVMETHOD(virtio_bus_with_feature,	  vtpci_with_feature),
209 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtpci_alloc_virtqueues),
210 	DEVMETHOD(virtio_bus_setup_intr,	  vtpci_setup_intr),
211 	DEVMETHOD(virtio_bus_stop,		  vtpci_stop),
212 	DEVMETHOD(virtio_bus_reinit,		  vtpci_reinit),
213 	DEVMETHOD(virtio_bus_reinit_complete,	  vtpci_reinit_complete),
214 	DEVMETHOD(virtio_bus_notify_vq,		  vtpci_notify_virtqueue),
215 	DEVMETHOD(virtio_bus_read_device_config,  vtpci_read_dev_config),
216 	DEVMETHOD(virtio_bus_write_device_config, vtpci_write_dev_config),
217 
218 	DEVMETHOD_END
219 };
220 
221 static driver_t vtpci_driver = {
222 	"virtio_pci",
223 	vtpci_methods,
224 	sizeof(struct vtpci_softc)
225 };
226 
227 devclass_t vtpci_devclass;
228 
229 DRIVER_MODULE(virtio_pci, pci, vtpci_driver, vtpci_devclass, 0, 0);
230 MODULE_VERSION(virtio_pci, 1);
231 MODULE_DEPEND(virtio_pci, pci, 1, 1, 1);
232 MODULE_DEPEND(virtio_pci, virtio, 1, 1, 1);
233 
234 static int
235 vtpci_probe(device_t dev)
236 {
237 	char desc[36];
238 	const char *name;
239 
240 	if (pci_get_vendor(dev) != VIRTIO_PCI_VENDORID)
241 		return (ENXIO);
242 
243 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MIN ||
244 	    pci_get_device(dev) > VIRTIO_PCI_DEVICEID_MAX)
245 		return (ENXIO);
246 
247 	if (pci_get_revid(dev) != VIRTIO_PCI_ABI_VERSION)
248 		return (ENXIO);
249 
250 	name = virtio_device_name(pci_get_subdevice(dev));
251 	if (name == NULL)
252 		name = "Unknown";
253 
254 	snprintf(desc, sizeof(desc), "VirtIO PCI %s adapter", name);
255 	device_set_desc_copy(dev, desc);
256 
257 	return (BUS_PROBE_DEFAULT);
258 }
259 
260 static int
261 vtpci_attach(device_t dev)
262 {
263 	struct vtpci_softc *sc;
264 	device_t child;
265 	int rid;
266 
267 	sc = device_get_softc(dev);
268 	sc->vtpci_dev = dev;
269 
270 	pci_enable_busmaster(dev);
271 
272 	rid = PCIR_BAR(0);
273 	sc->vtpci_res = bus_alloc_resource_any(dev, SYS_RES_IOPORT, &rid,
274 	    RF_ACTIVE);
275 	if (sc->vtpci_res == NULL) {
276 		device_printf(dev, "cannot map I/O space\n");
277 		return (ENXIO);
278 	}
279 
280 	if (pci_find_cap(dev, PCIY_MSI, NULL) != 0)
281 		sc->vtpci_flags |= VTPCI_FLAG_NO_MSI;
282 
283 	if (pci_find_cap(dev, PCIY_MSIX, NULL) == 0) {
284 		rid = PCIR_BAR(1);
285 		sc->vtpci_msix_res = bus_alloc_resource_any(dev,
286 		    SYS_RES_MEMORY, &rid, RF_ACTIVE);
287 	}
288 
289 	if (sc->vtpci_msix_res == NULL)
290 		sc->vtpci_flags |= VTPCI_FLAG_NO_MSIX;
291 
292 	vtpci_reset(sc);
293 
294 	/* Tell the host we've noticed this device. */
295 	vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
296 
297 	if ((child = device_add_child(dev, NULL, -1)) == NULL) {
298 		device_printf(dev, "cannot create child device\n");
299 		vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_FAILED);
300 		vtpci_detach(dev);
301 		return (ENOMEM);
302 	}
303 
304 	sc->vtpci_child_dev = child;
305 	vtpci_probe_and_attach_child(sc);
306 
307 	return (0);
308 }
309 
310 static int
311 vtpci_detach(device_t dev)
312 {
313 	struct vtpci_softc *sc;
314 	device_t child;
315 	int error;
316 
317 	sc = device_get_softc(dev);
318 
319 	if ((child = sc->vtpci_child_dev) != NULL) {
320 		error = device_delete_child(dev, child);
321 		if (error)
322 			return (error);
323 		sc->vtpci_child_dev = NULL;
324 	}
325 
326 	vtpci_reset(sc);
327 
328 	if (sc->vtpci_msix_res != NULL) {
329 		bus_release_resource(dev, SYS_RES_MEMORY, PCIR_BAR(1),
330 		    sc->vtpci_msix_res);
331 		sc->vtpci_msix_res = NULL;
332 	}
333 
334 	if (sc->vtpci_res != NULL) {
335 		bus_release_resource(dev, SYS_RES_IOPORT, PCIR_BAR(0),
336 		    sc->vtpci_res);
337 		sc->vtpci_res = NULL;
338 	}
339 
340 	return (0);
341 }
342 
343 static int
344 vtpci_suspend(device_t dev)
345 {
346 
347 	return (bus_generic_suspend(dev));
348 }
349 
350 static int
351 vtpci_resume(device_t dev)
352 {
353 
354 	return (bus_generic_resume(dev));
355 }
356 
357 static int
358 vtpci_shutdown(device_t dev)
359 {
360 
361 	(void) bus_generic_shutdown(dev);
362 	/* Forcibly stop the host device. */
363 	vtpci_stop(dev);
364 
365 	return (0);
366 }
367 
368 static void
369 vtpci_driver_added(device_t dev, driver_t *driver)
370 {
371 	struct vtpci_softc *sc;
372 
373 	sc = device_get_softc(dev);
374 
375 	vtpci_probe_and_attach_child(sc);
376 }
377 
378 static void
379 vtpci_child_detached(device_t dev, device_t child)
380 {
381 	struct vtpci_softc *sc;
382 
383 	sc = device_get_softc(dev);
384 
385 	vtpci_reset(sc);
386 	vtpci_release_child_resources(sc);
387 }
388 
389 static int
390 vtpci_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
391 {
392 	struct vtpci_softc *sc;
393 
394 	sc = device_get_softc(dev);
395 
396 	if (sc->vtpci_child_dev != child)
397 		return (ENOENT);
398 
399 	switch (index) {
400 	case VIRTIO_IVAR_DEVTYPE:
401 	case VIRTIO_IVAR_SUBDEVICE:
402 		*result = pci_get_subdevice(dev);
403 		break;
404 	case VIRTIO_IVAR_VENDOR:
405 		*result = pci_get_vendor(dev);
406 		break;
407 	case VIRTIO_IVAR_DEVICE:
408 		*result = pci_get_device(dev);
409 		break;
410 	case VIRTIO_IVAR_SUBVENDOR:
411 		*result = pci_get_subdevice(dev);
412 		break;
413 	default:
414 		return (ENOENT);
415 	}
416 
417 	return (0);
418 }
419 
420 static int
421 vtpci_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
422 {
423 	struct vtpci_softc *sc;
424 
425 	sc = device_get_softc(dev);
426 
427 	if (sc->vtpci_child_dev != child)
428 		return (ENOENT);
429 
430 	switch (index) {
431 	case VIRTIO_IVAR_FEATURE_DESC:
432 		sc->vtpci_child_feat_desc = (void *) value;
433 		break;
434 	default:
435 		return (ENOENT);
436 	}
437 
438 	return (0);
439 }
440 
441 static uint64_t
442 vtpci_negotiate_features(device_t dev, uint64_t child_features)
443 {
444 	struct vtpci_softc *sc;
445 	uint64_t host_features, features;
446 
447 	sc = device_get_softc(dev);
448 
449 	host_features = vtpci_read_config_4(sc, VIRTIO_PCI_HOST_FEATURES);
450 	vtpci_describe_features(sc, "host", host_features);
451 
452 	/*
453 	 * Limit negotiated features to what the driver, virtqueue, and
454 	 * host all support.
455 	 */
456 	features = host_features & child_features;
457 	features = virtqueue_filter_features(features);
458 	sc->vtpci_features = features;
459 
460 	vtpci_describe_features(sc, "negotiated", features);
461 	vtpci_write_config_4(sc, VIRTIO_PCI_GUEST_FEATURES, features);
462 
463 	return (features);
464 }
465 
466 static int
467 vtpci_with_feature(device_t dev, uint64_t feature)
468 {
469 	struct vtpci_softc *sc;
470 
471 	sc = device_get_softc(dev);
472 
473 	return ((sc->vtpci_features & feature) != 0);
474 }
475 
476 static int
477 vtpci_alloc_virtqueues(device_t dev, int flags, int nvqs,
478     struct vq_alloc_info *vq_info)
479 {
480 	struct vtpci_softc *sc;
481 	struct virtqueue *vq;
482 	struct vtpci_virtqueue *vqx;
483 	struct vq_alloc_info *info;
484 	int idx, error;
485 	uint16_t size;
486 
487 	sc = device_get_softc(dev);
488 
489 	if (sc->vtpci_nvqs != 0)
490 		return (EALREADY);
491 	if (nvqs <= 0)
492 		return (EINVAL);
493 
494 	sc->vtpci_vqs = malloc(nvqs * sizeof(struct vtpci_virtqueue),
495 	    M_DEVBUF, M_NOWAIT | M_ZERO);
496 	if (sc->vtpci_vqs == NULL)
497 		return (ENOMEM);
498 
499 	for (idx = 0; idx < nvqs; idx++) {
500 		vqx = &sc->vtpci_vqs[idx];
501 		info = &vq_info[idx];
502 
503 		vtpci_select_virtqueue(sc, idx);
504 		size = vtpci_read_config_2(sc, VIRTIO_PCI_QUEUE_NUM);
505 
506 		error = virtqueue_alloc(dev, idx, size, VIRTIO_PCI_VRING_ALIGN,
507 		    0xFFFFFFFFUL, info, &vq);
508 		if (error) {
509 			device_printf(dev,
510 			    "cannot allocate virtqueue %d: %d\n", idx, error);
511 			break;
512 		}
513 
514 		vtpci_write_config_4(sc, VIRTIO_PCI_QUEUE_PFN,
515 		    virtqueue_paddr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT);
516 
517 		vqx->vtv_vq = *info->vqai_vq = vq;
518 		vqx->vtv_no_intr = info->vqai_intr == NULL;
519 
520 		sc->vtpci_nvqs++;
521 	}
522 
523 	if (error)
524 		vtpci_free_virtqueues(sc);
525 
526 	return (error);
527 }
528 
529 static int
530 vtpci_setup_intr(device_t dev, enum intr_type type)
531 {
532 	struct vtpci_softc *sc;
533 	int attempt, error;
534 
535 	sc = device_get_softc(dev);
536 
537 	for (attempt = 0; attempt < 5; attempt++) {
538 		/*
539 		 * Start with the most desirable interrupt configuration and
540 		 * fallback towards less desirable ones.
541 		 */
542 		switch (attempt) {
543 		case 0:
544 			error = vtpci_alloc_intr_msix_pervq(sc);
545 			break;
546 		case 1:
547 			error = vtpci_alloc_intr_msix_shared(sc);
548 			break;
549 		case 2:
550 			error = vtpci_alloc_intr_msi(sc);
551 			break;
552 		case 3:
553 			error = vtpci_alloc_intr_legacy(sc);
554 			break;
555 		default:
556 			device_printf(dev,
557 			    "exhausted all interrupt allocation attempts\n");
558 			return (ENXIO);
559 		}
560 
561 		if (error == 0 && vtpci_setup_interrupts(sc, type) == 0)
562 			break;
563 
564 		vtpci_cleanup_setup_intr_attempt(sc);
565 	}
566 
567 	if (bootverbose) {
568 		if (sc->vtpci_flags & VTPCI_FLAG_LEGACY)
569 			device_printf(dev, "using legacy interrupt\n");
570 		else if (sc->vtpci_flags & VTPCI_FLAG_MSI)
571 			device_printf(dev, "using MSI interrupt\n");
572 		else if (sc->vtpci_flags & VTPCI_FLAG_SHARED_MSIX)
573 			device_printf(dev, "using shared MSIX interrupts\n");
574 		else
575 			device_printf(dev, "using per VQ MSIX interrupts\n");
576 	}
577 
578 	return (0);
579 }
580 
581 static void
582 vtpci_stop(device_t dev)
583 {
584 
585 	vtpci_reset(device_get_softc(dev));
586 }
587 
588 static int
589 vtpci_reinit(device_t dev, uint64_t features)
590 {
591 	struct vtpci_softc *sc;
592 	int idx, error;
593 
594 	sc = device_get_softc(dev);
595 
596 	/*
597 	 * Redrive the device initialization. This is a bit of an abuse of
598 	 * the specification, but VirtualBox, QEMU/KVM, and BHyVe seem to
599 	 * play nice.
600 	 *
601 	 * We do not allow the host device to change from what was originally
602 	 * negotiated beyond what the guest driver changed. MSIX state should
603 	 * not change, number of virtqueues and their size remain the same, etc.
604 	 * This will need to be rethought when we want to support migration.
605 	 */
606 
607 	if (vtpci_get_status(dev) != VIRTIO_CONFIG_STATUS_RESET)
608 		vtpci_stop(dev);
609 
610 	/*
611 	 * Quickly drive the status through ACK and DRIVER. The device
612 	 * does not become usable again until vtpci_reinit_complete().
613 	 */
614 	vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
615 	vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER);
616 
617 	vtpci_negotiate_features(dev, features);
618 
619 	for (idx = 0; idx < sc->vtpci_nvqs; idx++) {
620 		error = vtpci_reinit_virtqueue(sc, idx);
621 		if (error)
622 			return (error);
623 	}
624 
625 	if (sc->vtpci_flags & VTPCI_FLAG_MSIX) {
626 		error = vtpci_set_host_msix_vectors(sc);
627 		if (error)
628 			return (error);
629 	}
630 
631 	return (0);
632 }
633 
634 static void
635 vtpci_reinit_complete(device_t dev)
636 {
637 
638 	vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER_OK);
639 }
640 
641 static void
642 vtpci_notify_virtqueue(device_t dev, uint16_t queue)
643 {
644 	struct vtpci_softc *sc;
645 
646 	sc = device_get_softc(dev);
647 
648 	vtpci_write_config_2(sc, VIRTIO_PCI_QUEUE_NOTIFY, queue);
649 }
650 
651 static uint8_t
652 vtpci_get_status(device_t dev)
653 {
654 	struct vtpci_softc *sc;
655 
656 	sc = device_get_softc(dev);
657 
658 	return (vtpci_read_config_1(sc, VIRTIO_PCI_STATUS));
659 }
660 
661 static void
662 vtpci_set_status(device_t dev, uint8_t status)
663 {
664 	struct vtpci_softc *sc;
665 
666 	sc = device_get_softc(dev);
667 
668 	if (status != VIRTIO_CONFIG_STATUS_RESET)
669 		status |= vtpci_get_status(dev);
670 
671 	vtpci_write_config_1(sc, VIRTIO_PCI_STATUS, status);
672 }
673 
674 static void
675 vtpci_read_dev_config(device_t dev, bus_size_t offset,
676     void *dst, int length)
677 {
678 	struct vtpci_softc *sc;
679 	bus_size_t off;
680 	uint8_t *d;
681 	int size;
682 
683 	sc = device_get_softc(dev);
684 	off = VIRTIO_PCI_CONFIG(sc) + offset;
685 
686 	for (d = dst; length > 0; d += size, off += size, length -= size) {
687 		if (length >= 4) {
688 			size = 4;
689 			*(uint32_t *)d = vtpci_read_config_4(sc, off);
690 		} else if (length >= 2) {
691 			size = 2;
692 			*(uint16_t *)d = vtpci_read_config_2(sc, off);
693 		} else {
694 			size = 1;
695 			*d = vtpci_read_config_1(sc, off);
696 		}
697 	}
698 }
699 
700 static void
701 vtpci_write_dev_config(device_t dev, bus_size_t offset,
702     void *src, int length)
703 {
704 	struct vtpci_softc *sc;
705 	bus_size_t off;
706 	uint8_t *s;
707 	int size;
708 
709 	sc = device_get_softc(dev);
710 	off = VIRTIO_PCI_CONFIG(sc) + offset;
711 
712 	for (s = src; length > 0; s += size, off += size, length -= size) {
713 		if (length >= 4) {
714 			size = 4;
715 			vtpci_write_config_4(sc, off, *(uint32_t *)s);
716 		} else if (length >= 2) {
717 			size = 2;
718 			vtpci_write_config_2(sc, off, *(uint16_t *)s);
719 		} else {
720 			size = 1;
721 			vtpci_write_config_1(sc, off, *s);
722 		}
723 	}
724 }
725 
726 static void
727 vtpci_describe_features(struct vtpci_softc *sc, const char *msg,
728     uint64_t features)
729 {
730 	device_t dev, child;
731 
732 	dev = sc->vtpci_dev;
733 	child = sc->vtpci_child_dev;
734 
735 	if (device_is_attached(child) || bootverbose == 0)
736 		return;
737 
738 	virtio_describe(dev, msg, features, sc->vtpci_child_feat_desc);
739 }
740 
741 static void
742 vtpci_probe_and_attach_child(struct vtpci_softc *sc)
743 {
744 	device_t dev, child;
745 
746 	dev = sc->vtpci_dev;
747 	child = sc->vtpci_child_dev;
748 
749 	if (child == NULL)
750 		return;
751 
752 	if (device_get_state(child) != DS_NOTPRESENT)
753 		return;
754 
755 	if (device_probe(child) != 0)
756 		return;
757 
758 	vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER);
759 	if (device_attach(child) != 0) {
760 		vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_FAILED);
761 		vtpci_reset(sc);
762 		vtpci_release_child_resources(sc);
763 		/* Reset status for future attempt. */
764 		vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
765 	} else {
766 		vtpci_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER_OK);
767 		VIRTIO_ATTACH_COMPLETED(child);
768 	}
769 }
770 
771 static int
772 vtpci_alloc_msix(struct vtpci_softc *sc, int nvectors)
773 {
774 	device_t dev;
775 	int nmsix, cnt, required;
776 
777 	dev = sc->vtpci_dev;
778 
779 	/* Allocate an additional vector for the config changes. */
780 	required = nvectors + 1;
781 
782 	nmsix = pci_msix_count(dev);
783 	if (nmsix < required)
784 		return (1);
785 
786 	cnt = required;
787 	if (pci_alloc_msix(dev, &cnt) == 0 && cnt >= required) {
788 		sc->vtpci_nmsix_resources = required;
789 		return (0);
790 	}
791 
792 	pci_release_msi(dev);
793 
794 	return (1);
795 }
796 
797 static int
798 vtpci_alloc_msi(struct vtpci_softc *sc)
799 {
800 	device_t dev;
801 	int nmsi, cnt, required;
802 
803 	dev = sc->vtpci_dev;
804 	required = 1;
805 
806 	nmsi = pci_msi_count(dev);
807 	if (nmsi < required)
808 		return (1);
809 
810 	cnt = required;
811 	if (pci_alloc_msi(dev, &cnt) == 0 && cnt >= required)
812 		return (0);
813 
814 	pci_release_msi(dev);
815 
816 	return (1);
817 }
818 
819 static int
820 vtpci_alloc_intr_msix_pervq(struct vtpci_softc *sc)
821 {
822 	int i, nvectors, error;
823 
824 	if (vtpci_disable_msix != 0 ||
825 	    sc->vtpci_flags & VTPCI_FLAG_NO_MSIX)
826 		return (ENOTSUP);
827 
828 	for (nvectors = 0, i = 0; i < sc->vtpci_nvqs; i++) {
829 		if (sc->vtpci_vqs[i].vtv_no_intr == 0)
830 			nvectors++;
831 	}
832 
833 	error = vtpci_alloc_msix(sc, nvectors);
834 	if (error)
835 		return (error);
836 
837 	sc->vtpci_flags |= VTPCI_FLAG_MSIX;
838 
839 	return (0);
840 }
841 
842 static int
843 vtpci_alloc_intr_msix_shared(struct vtpci_softc *sc)
844 {
845 	int error;
846 
847 	if (vtpci_disable_msix != 0 ||
848 	    sc->vtpci_flags & VTPCI_FLAG_NO_MSIX)
849 		return (ENOTSUP);
850 
851 	error = vtpci_alloc_msix(sc, 1);
852 	if (error)
853 		return (error);
854 
855 	sc->vtpci_flags |= VTPCI_FLAG_MSIX | VTPCI_FLAG_SHARED_MSIX;
856 
857 	return (0);
858 }
859 
860 static int
861 vtpci_alloc_intr_msi(struct vtpci_softc *sc)
862 {
863 	int error;
864 
865 	/* Only BHyVe supports MSI. */
866 	if (sc->vtpci_flags & VTPCI_FLAG_NO_MSI)
867 		return (ENOTSUP);
868 
869 	error = vtpci_alloc_msi(sc);
870 	if (error)
871 		return (error);
872 
873 	sc->vtpci_flags |= VTPCI_FLAG_MSI;
874 
875 	return (0);
876 }
877 
878 static int
879 vtpci_alloc_intr_legacy(struct vtpci_softc *sc)
880 {
881 
882 	sc->vtpci_flags |= VTPCI_FLAG_LEGACY;
883 
884 	return (0);
885 }
886 
887 static int
888 vtpci_alloc_interrupt(struct vtpci_softc *sc, int rid, int flags,
889     struct vtpci_interrupt *intr)
890 {
891 	struct resource *irq;
892 
893 	irq = bus_alloc_resource_any(sc->vtpci_dev, SYS_RES_IRQ, &rid, flags);
894 	if (irq == NULL)
895 		return (ENXIO);
896 
897 	intr->vti_irq = irq;
898 	intr->vti_rid = rid;
899 
900 	return (0);
901 }
902 
903 static int
904 vtpci_alloc_intr_resources(struct vtpci_softc *sc)
905 {
906 	struct vtpci_interrupt *intr;
907 	int i, rid, flags, nvq_intrs, error;
908 
909 	rid = 0;
910 	flags = RF_ACTIVE;
911 
912 	if (sc->vtpci_flags & VTPCI_FLAG_LEGACY)
913 		flags |= RF_SHAREABLE;
914 	else
915 		rid = 1;
916 
917 	/*
918 	 * For legacy and MSI interrupts, this single resource handles all
919 	 * interrupts. For MSIX, this resource is used for the configuration
920 	 * changed interrupt.
921 	 */
922 	intr = &sc->vtpci_device_interrupt;
923 	error = vtpci_alloc_interrupt(sc, rid, flags, intr);
924 	if (error || sc->vtpci_flags & (VTPCI_FLAG_LEGACY | VTPCI_FLAG_MSI))
925 		return (error);
926 
927 	/* Subtract one for the configuration changed interrupt. */
928 	nvq_intrs = sc->vtpci_nmsix_resources - 1;
929 
930 	intr = sc->vtpci_msix_vq_interrupts = malloc(nvq_intrs *
931 	    sizeof(struct vtpci_interrupt), M_DEVBUF, M_NOWAIT | M_ZERO);
932 	if (sc->vtpci_msix_vq_interrupts == NULL)
933 		return (ENOMEM);
934 
935 	for (i = 0, rid++; i < nvq_intrs; i++, rid++, intr++) {
936 		error = vtpci_alloc_interrupt(sc, rid, flags, intr);
937 		if (error)
938 			return (error);
939 	}
940 
941 	return (0);
942 }
943 
944 static int
945 vtpci_setup_legacy_interrupt(struct vtpci_softc *sc, enum intr_type type)
946 {
947 	struct vtpci_interrupt *intr;
948 	int error;
949 
950 	intr = &sc->vtpci_device_interrupt;
951 	error = bus_setup_intr(sc->vtpci_dev, intr->vti_irq, type, NULL,
952 	    vtpci_legacy_intr, sc, &intr->vti_handler);
953 
954 	return (error);
955 }
956 
957 static int
958 vtpci_setup_pervq_msix_interrupts(struct vtpci_softc *sc, enum intr_type type)
959 {
960 	struct vtpci_virtqueue *vqx;
961 	struct vtpci_interrupt *intr;
962 	int i, error;
963 
964 	intr = sc->vtpci_msix_vq_interrupts;
965 
966 	for (i = 0; i < sc->vtpci_nvqs; i++) {
967 		vqx = &sc->vtpci_vqs[i];
968 
969 		if (vqx->vtv_no_intr)
970 			continue;
971 
972 		error = bus_setup_intr(sc->vtpci_dev, intr->vti_irq, type,
973 		    vtpci_vq_intr_filter, vtpci_vq_intr, vqx->vtv_vq,
974 		    &intr->vti_handler);
975 		if (error)
976 			return (error);
977 
978 		intr++;
979 	}
980 
981 	return (0);
982 }
983 
984 static int
985 vtpci_setup_msix_interrupts(struct vtpci_softc *sc, enum intr_type type)
986 {
987 	device_t dev;
988 	struct vtpci_interrupt *intr;
989 	int error;
990 
991 	dev = sc->vtpci_dev;
992 	intr = &sc->vtpci_device_interrupt;
993 
994 	error = bus_setup_intr(dev, intr->vti_irq, type, NULL,
995 	    vtpci_config_intr, sc, &intr->vti_handler);
996 	if (error)
997 		return (error);
998 
999 	if (sc->vtpci_flags & VTPCI_FLAG_SHARED_MSIX) {
1000 		intr = sc->vtpci_msix_vq_interrupts;
1001 		error = bus_setup_intr(dev, intr->vti_irq, type,
1002 		    vtpci_vq_shared_intr_filter, vtpci_vq_shared_intr, sc,
1003 		    &intr->vti_handler);
1004 	} else
1005 		error = vtpci_setup_pervq_msix_interrupts(sc, type);
1006 
1007 	return (error ? error : vtpci_set_host_msix_vectors(sc));
1008 }
1009 
1010 static int
1011 vtpci_setup_interrupts(struct vtpci_softc *sc, enum intr_type type)
1012 {
1013 	int error;
1014 
1015 	type |= INTR_MPSAFE;
1016 	KASSERT(sc->vtpci_flags & VTPCI_FLAG_ITYPE_MASK,
1017 	    ("%s: no interrupt type selected %#x", __func__, sc->vtpci_flags));
1018 
1019 	error = vtpci_alloc_intr_resources(sc);
1020 	if (error)
1021 		return (error);
1022 
1023 	if (sc->vtpci_flags & VTPCI_FLAG_LEGACY)
1024 		error = vtpci_setup_legacy_interrupt(sc, type);
1025 	else if (sc->vtpci_flags & VTPCI_FLAG_MSI)
1026 		error = vtpci_setup_msi_interrupt(sc, type);
1027 	else
1028 		error = vtpci_setup_msix_interrupts(sc, type);
1029 
1030 	return (error);
1031 }
1032 
1033 static int
1034 vtpci_register_msix_vector(struct vtpci_softc *sc, int offset,
1035     struct vtpci_interrupt *intr)
1036 {
1037 	device_t dev;
1038 	uint16_t vector;
1039 
1040 	dev = sc->vtpci_dev;
1041 
1042 	if (intr != NULL) {
1043 		/* Map from guest rid to host vector. */
1044 		vector = intr->vti_rid - 1;
1045 	} else
1046 		vector = VIRTIO_MSI_NO_VECTOR;
1047 
1048 	vtpci_write_config_2(sc, offset, vector);
1049 
1050 	/* Read vector to determine if the host had sufficient resources. */
1051 	if (vtpci_read_config_2(sc, offset) != vector) {
1052 		device_printf(dev,
1053 		    "insufficient host resources for MSIX interrupts\n");
1054 		return (ENODEV);
1055 	}
1056 
1057 	return (0);
1058 }
1059 
1060 static int
1061 vtpci_set_host_msix_vectors(struct vtpci_softc *sc)
1062 {
1063 	struct vtpci_interrupt *intr, *tintr;
1064 	int idx, offset, error;
1065 
1066 	intr = &sc->vtpci_device_interrupt;
1067 	offset = VIRTIO_MSI_CONFIG_VECTOR;
1068 
1069 	error = vtpci_register_msix_vector(sc, offset, intr);
1070 	if (error)
1071 		return (error);
1072 
1073 	intr = sc->vtpci_msix_vq_interrupts;
1074 	offset = VIRTIO_MSI_QUEUE_VECTOR;
1075 
1076 	for (idx = 0; idx < sc->vtpci_nvqs; idx++) {
1077 		vtpci_select_virtqueue(sc, idx);
1078 
1079 		if (sc->vtpci_vqs[idx].vtv_no_intr)
1080 			tintr = NULL;
1081 		else
1082 			tintr = intr;
1083 
1084 		error = vtpci_register_msix_vector(sc, offset, tintr);
1085 		if (error)
1086 			break;
1087 
1088 		/*
1089 		 * For shared MSIX, all the virtqueues share the first
1090 		 * interrupt.
1091 		 */
1092 		if (!sc->vtpci_vqs[idx].vtv_no_intr &&
1093 		    (sc->vtpci_flags & VTPCI_FLAG_SHARED_MSIX) == 0)
1094 			intr++;
1095 	}
1096 
1097 	return (error);
1098 }
1099 
1100 static int
1101 vtpci_reinit_virtqueue(struct vtpci_softc *sc, int idx)
1102 {
1103 	struct vtpci_virtqueue *vqx;
1104 	struct virtqueue *vq;
1105 	int error;
1106 	uint16_t size;
1107 
1108 	vqx = &sc->vtpci_vqs[idx];
1109 	vq = vqx->vtv_vq;
1110 
1111 	KASSERT(vq != NULL, ("%s: vq %d not allocated", __func__, idx));
1112 
1113 	vtpci_select_virtqueue(sc, idx);
1114 	size = vtpci_read_config_2(sc, VIRTIO_PCI_QUEUE_NUM);
1115 
1116 	error = virtqueue_reinit(vq, size);
1117 	if (error)
1118 		return (error);
1119 
1120 	vtpci_write_config_4(sc, VIRTIO_PCI_QUEUE_PFN,
1121 	    virtqueue_paddr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT);
1122 
1123 	return (0);
1124 }
1125 
1126 static void
1127 vtpci_free_interrupt(struct vtpci_softc *sc, struct vtpci_interrupt *intr)
1128 {
1129 	device_t dev;
1130 
1131 	dev = sc->vtpci_dev;
1132 
1133 	if (intr->vti_handler != NULL) {
1134 		bus_teardown_intr(dev, intr->vti_irq, intr->vti_handler);
1135 		intr->vti_handler = NULL;
1136 	}
1137 
1138 	if (intr->vti_irq != NULL) {
1139 		bus_release_resource(dev, SYS_RES_IRQ, intr->vti_rid,
1140 		    intr->vti_irq);
1141 		intr->vti_irq = NULL;
1142 		intr->vti_rid = -1;
1143 	}
1144 }
1145 
1146 static void
1147 vtpci_free_interrupts(struct vtpci_softc *sc)
1148 {
1149 	struct vtpci_interrupt *intr;
1150 	int i, nvq_intrs;
1151 
1152 	vtpci_free_interrupt(sc, &sc->vtpci_device_interrupt);
1153 
1154 	if (sc->vtpci_nmsix_resources != 0) {
1155 		nvq_intrs = sc->vtpci_nmsix_resources - 1;
1156 		sc->vtpci_nmsix_resources = 0;
1157 
1158 		intr = sc->vtpci_msix_vq_interrupts;
1159 		if (intr != NULL) {
1160 			for (i = 0; i < nvq_intrs; i++, intr++)
1161 				vtpci_free_interrupt(sc, intr);
1162 
1163 			free(sc->vtpci_msix_vq_interrupts, M_DEVBUF);
1164 			sc->vtpci_msix_vq_interrupts = NULL;
1165 		}
1166 	}
1167 
1168 	if (sc->vtpci_flags & (VTPCI_FLAG_MSI | VTPCI_FLAG_MSIX))
1169 		pci_release_msi(sc->vtpci_dev);
1170 
1171 	sc->vtpci_flags &= ~VTPCI_FLAG_ITYPE_MASK;
1172 }
1173 
1174 static void
1175 vtpci_free_virtqueues(struct vtpci_softc *sc)
1176 {
1177 	struct vtpci_virtqueue *vqx;
1178 	int idx;
1179 
1180 	for (idx = 0; idx < sc->vtpci_nvqs; idx++) {
1181 		vqx = &sc->vtpci_vqs[idx];
1182 
1183 		vtpci_select_virtqueue(sc, idx);
1184 		vtpci_write_config_4(sc, VIRTIO_PCI_QUEUE_PFN, 0);
1185 
1186 		virtqueue_free(vqx->vtv_vq);
1187 		vqx->vtv_vq = NULL;
1188 	}
1189 
1190 	free(sc->vtpci_vqs, M_DEVBUF);
1191 	sc->vtpci_vqs = NULL;
1192 	sc->vtpci_nvqs = 0;
1193 }
1194 
1195 static void
1196 vtpci_release_child_resources(struct vtpci_softc *sc)
1197 {
1198 
1199 	vtpci_free_interrupts(sc);
1200 	vtpci_free_virtqueues(sc);
1201 }
1202 
1203 static void
1204 vtpci_cleanup_setup_intr_attempt(struct vtpci_softc *sc)
1205 {
1206 	int idx;
1207 
1208 	if (sc->vtpci_flags & VTPCI_FLAG_MSIX) {
1209 		vtpci_write_config_2(sc, VIRTIO_MSI_CONFIG_VECTOR,
1210 		    VIRTIO_MSI_NO_VECTOR);
1211 
1212 		for (idx = 0; idx < sc->vtpci_nvqs; idx++) {
1213 			vtpci_select_virtqueue(sc, idx);
1214 			vtpci_write_config_2(sc, VIRTIO_MSI_QUEUE_VECTOR,
1215 			    VIRTIO_MSI_NO_VECTOR);
1216 		}
1217 	}
1218 
1219 	vtpci_free_interrupts(sc);
1220 }
1221 
1222 static void
1223 vtpci_reset(struct vtpci_softc *sc)
1224 {
1225 
1226 	/*
1227 	 * Setting the status to RESET sets the host device to
1228 	 * the original, uninitialized state.
1229 	 */
1230 	vtpci_set_status(sc->vtpci_dev, VIRTIO_CONFIG_STATUS_RESET);
1231 }
1232 
1233 static void
1234 vtpci_select_virtqueue(struct vtpci_softc *sc, int idx)
1235 {
1236 
1237 	vtpci_write_config_2(sc, VIRTIO_PCI_QUEUE_SEL, idx);
1238 }
1239 
1240 static void
1241 vtpci_legacy_intr(void *xsc)
1242 {
1243 	struct vtpci_softc *sc;
1244 	struct vtpci_virtqueue *vqx;
1245 	int i;
1246 	uint8_t isr;
1247 
1248 	sc = xsc;
1249 	vqx = &sc->vtpci_vqs[0];
1250 
1251 	/* Reading the ISR also clears it. */
1252 	isr = vtpci_read_config_1(sc, VIRTIO_PCI_ISR);
1253 
1254 	if (isr & VIRTIO_PCI_ISR_CONFIG)
1255 		vtpci_config_intr(sc);
1256 
1257 	if (isr & VIRTIO_PCI_ISR_INTR) {
1258 		for (i = 0; i < sc->vtpci_nvqs; i++, vqx++) {
1259 			if (vqx->vtv_no_intr == 0)
1260 				virtqueue_intr(vqx->vtv_vq);
1261 		}
1262 	}
1263 }
1264 
1265 static int
1266 vtpci_vq_shared_intr_filter(void *xsc)
1267 {
1268 	struct vtpci_softc *sc;
1269 	struct vtpci_virtqueue *vqx;
1270 	int i, rc;
1271 
1272 	rc = 0;
1273 	sc = xsc;
1274 	vqx = &sc->vtpci_vqs[0];
1275 
1276 	for (i = 0; i < sc->vtpci_nvqs; i++, vqx++) {
1277 		if (vqx->vtv_no_intr == 0)
1278 			rc |= virtqueue_intr_filter(vqx->vtv_vq);
1279 	}
1280 
1281 	return (rc ? FILTER_SCHEDULE_THREAD : FILTER_STRAY);
1282 }
1283 
1284 static void
1285 vtpci_vq_shared_intr(void *xsc)
1286 {
1287 	struct vtpci_softc *sc;
1288 	struct vtpci_virtqueue *vqx;
1289 	int i;
1290 
1291 	sc = xsc;
1292 	vqx = &sc->vtpci_vqs[0];
1293 
1294 	for (i = 0; i < sc->vtpci_nvqs; i++, vqx++) {
1295 		if (vqx->vtv_no_intr == 0)
1296 			virtqueue_intr(vqx->vtv_vq);
1297 	}
1298 }
1299 
1300 static int
1301 vtpci_vq_intr_filter(void *xvq)
1302 {
1303 	struct virtqueue *vq;
1304 	int rc;
1305 
1306 	vq = xvq;
1307 	rc = virtqueue_intr_filter(vq);
1308 
1309 	return (rc ? FILTER_SCHEDULE_THREAD : FILTER_STRAY);
1310 }
1311 
1312 static void
1313 vtpci_vq_intr(void *xvq)
1314 {
1315 	struct virtqueue *vq;
1316 
1317 	vq = xvq;
1318 	virtqueue_intr(vq);
1319 }
1320 
1321 static void
1322 vtpci_config_intr(void *xsc)
1323 {
1324 	struct vtpci_softc *sc;
1325 	device_t child;
1326 
1327 	sc = xsc;
1328 	child = sc->vtpci_child_dev;
1329 
1330 	if (child != NULL)
1331 		VIRTIO_CONFIG_CHANGE(child);
1332 }
1333