xref: /freebsd/sys/dev/virtio/pci/virtio_pci_modern.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2017, 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 modern 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/lock.h>
38 #include <sys/kernel.h>
39 #include <sys/module.h>
40 
41 #include <machine/bus.h>
42 #include <machine/cpu.h>
43 #include <machine/resource.h>
44 #include <sys/bus.h>
45 #include <sys/rman.h>
46 
47 #include <dev/pci/pcivar.h>
48 #include <dev/pci/pcireg.h>
49 
50 #include <dev/virtio/virtio.h>
51 #include <dev/virtio/virtqueue.h>
52 #include <dev/virtio/pci/virtio_pci.h>
53 #include <dev/virtio/pci/virtio_pci_modern_var.h>
54 
55 #include "virtio_bus_if.h"
56 #include "virtio_pci_if.h"
57 #include "virtio_if.h"
58 
59 struct vtpci_modern_resource_map {
60 	struct resource_map	vtrm_map;
61 	int			vtrm_cap_offset;
62 	int			vtrm_bar;
63 	int			vtrm_offset;
64 	int			vtrm_length;
65 	int			vtrm_type;	/* SYS_RES_{MEMORY, IOPORT} */
66 };
67 
68 struct vtpci_modern_bar_resource {
69 	struct resource		*vtbr_res;
70 	int			 vtbr_type;
71 };
72 
73 struct vtpci_modern_softc {
74 	device_t			 vtpci_dev;
75 	struct vtpci_common		 vtpci_common;
76 	uint32_t			 vtpci_notify_offset_multiplier;
77 	uint16_t			 vtpci_devid;
78 	int				 vtpci_msix_bar;
79 	struct resource			*vtpci_msix_res;
80 
81 	struct vtpci_modern_resource_map vtpci_common_res_map;
82 	struct vtpci_modern_resource_map vtpci_notify_res_map;
83 	struct vtpci_modern_resource_map vtpci_isr_res_map;
84 	struct vtpci_modern_resource_map vtpci_device_res_map;
85 
86 #define VTPCI_MODERN_MAX_BARS		6
87 	struct vtpci_modern_bar_resource vtpci_bar_res[VTPCI_MODERN_MAX_BARS];
88 };
89 
90 static int	vtpci_modern_probe(device_t);
91 static int	vtpci_modern_attach(device_t);
92 static int	vtpci_modern_detach(device_t);
93 static int	vtpci_modern_suspend(device_t);
94 static int	vtpci_modern_resume(device_t);
95 static int	vtpci_modern_shutdown(device_t);
96 
97 static void	vtpci_modern_driver_added(device_t, driver_t *);
98 static void	vtpci_modern_child_detached(device_t, device_t);
99 static int	vtpci_modern_read_ivar(device_t, device_t, int, uintptr_t *);
100 static int	vtpci_modern_write_ivar(device_t, device_t, int, uintptr_t);
101 
102 static uint8_t	vtpci_modern_read_isr(device_t);
103 static uint16_t	vtpci_modern_get_vq_size(device_t, int);
104 static bus_size_t vtpci_modern_get_vq_notify_off(device_t, int);
105 static void	vtpci_modern_set_vq(device_t, struct virtqueue *);
106 static void	vtpci_modern_disable_vq(device_t, int);
107 static int	vtpci_modern_register_msix(struct vtpci_modern_softc *, int,
108 		    struct vtpci_interrupt *);
109 static int	vtpci_modern_register_cfg_msix(device_t,
110 		    struct vtpci_interrupt *);
111 static int	vtpci_modern_register_vq_msix(device_t, int idx,
112 		    struct vtpci_interrupt *);
113 
114 static uint64_t	vtpci_modern_negotiate_features(device_t, uint64_t);
115 static int	vtpci_modern_finalize_features(device_t);
116 static int	vtpci_modern_with_feature(device_t, uint64_t);
117 static int	vtpci_modern_alloc_virtqueues(device_t, int, int,
118 		    struct vq_alloc_info *);
119 static int	vtpci_modern_setup_interrupts(device_t, enum intr_type);
120 static void	vtpci_modern_stop(device_t);
121 static int	vtpci_modern_reinit(device_t, uint64_t);
122 static void	vtpci_modern_reinit_complete(device_t);
123 static void	vtpci_modern_notify_vq(device_t, uint16_t, bus_size_t);
124 static int	vtpci_modern_config_generation(device_t);
125 static void	vtpci_modern_read_dev_config(device_t, bus_size_t, void *, int);
126 static void	vtpci_modern_write_dev_config(device_t, bus_size_t, const void *, int);
127 
128 static int	vtpci_modern_probe_configs(device_t);
129 static int	vtpci_modern_find_cap(device_t, uint8_t, int *);
130 static int	vtpci_modern_map_configs(struct vtpci_modern_softc *);
131 static void	vtpci_modern_unmap_configs(struct vtpci_modern_softc *);
132 static int	vtpci_modern_find_cap_resource(struct vtpci_modern_softc *,
133 		     uint8_t, int, int, struct vtpci_modern_resource_map *);
134 static int	vtpci_modern_bar_type(struct vtpci_modern_softc *, int);
135 static struct resource *vtpci_modern_get_bar_resource(
136 		    struct vtpci_modern_softc *, int, int);
137 static struct resource *vtpci_modern_alloc_bar_resource(
138 		    struct vtpci_modern_softc *, int, int);
139 static void	vtpci_modern_free_bar_resources(struct vtpci_modern_softc *);
140 static int	vtpci_modern_alloc_resource_map(struct vtpci_modern_softc *,
141 		    struct vtpci_modern_resource_map *);
142 static void	vtpci_modern_free_resource_map(struct vtpci_modern_softc *,
143 		    struct vtpci_modern_resource_map *);
144 static void	vtpci_modern_alloc_msix_resource(struct vtpci_modern_softc *);
145 static void	vtpci_modern_free_msix_resource(struct vtpci_modern_softc *);
146 
147 static void	vtpci_modern_probe_and_attach_child(struct vtpci_modern_softc *);
148 
149 static uint64_t vtpci_modern_read_features(struct vtpci_modern_softc *);
150 static void	vtpci_modern_write_features(struct vtpci_modern_softc *,
151 		    uint64_t);
152 static void	vtpci_modern_select_virtqueue(struct vtpci_modern_softc *, int);
153 static uint8_t	vtpci_modern_get_status(struct vtpci_modern_softc *);
154 static void	vtpci_modern_set_status(struct vtpci_modern_softc *, uint8_t);
155 static void	vtpci_modern_reset(struct vtpci_modern_softc *);
156 static void	vtpci_modern_enable_virtqueues(struct vtpci_modern_softc *);
157 
158 static uint8_t	vtpci_modern_read_common_1(struct vtpci_modern_softc *,
159 		    bus_size_t);
160 static uint16_t vtpci_modern_read_common_2(struct vtpci_modern_softc *,
161 		    bus_size_t);
162 static uint32_t vtpci_modern_read_common_4(struct vtpci_modern_softc *,
163 		    bus_size_t);
164 static void	vtpci_modern_write_common_1(struct vtpci_modern_softc *,
165 		     bus_size_t, uint8_t);
166 static void	vtpci_modern_write_common_2(struct vtpci_modern_softc *,
167 		     bus_size_t, uint16_t);
168 static void	vtpci_modern_write_common_4(struct vtpci_modern_softc *,
169 		    bus_size_t, uint32_t);
170 static void	vtpci_modern_write_common_8(struct vtpci_modern_softc *,
171 		    bus_size_t, uint64_t);
172 static void	vtpci_modern_write_notify_2(struct vtpci_modern_softc *,
173 		    bus_size_t, uint16_t);
174 static uint8_t  vtpci_modern_read_isr_1(struct vtpci_modern_softc *,
175 		    bus_size_t);
176 static uint8_t	vtpci_modern_read_device_1(struct vtpci_modern_softc *,
177 		    bus_size_t);
178 static uint16_t vtpci_modern_read_device_2(struct vtpci_modern_softc *,
179 		    bus_size_t);
180 static uint32_t vtpci_modern_read_device_4(struct vtpci_modern_softc *,
181 		    bus_size_t);
182 static uint64_t vtpci_modern_read_device_8(struct vtpci_modern_softc *,
183 		    bus_size_t);
184 static void	vtpci_modern_write_device_1(struct vtpci_modern_softc *,
185 		    bus_size_t, uint8_t);
186 static void	vtpci_modern_write_device_2(struct vtpci_modern_softc *,
187 		    bus_size_t, uint16_t);
188 static void	vtpci_modern_write_device_4(struct vtpci_modern_softc *,
189 		    bus_size_t, uint32_t);
190 static void	vtpci_modern_write_device_8(struct vtpci_modern_softc *,
191 		    bus_size_t, uint64_t);
192 
193 /* Tunables. */
194 static int vtpci_modern_transitional = 0;
195 TUNABLE_INT("hw.virtio.pci.transitional", &vtpci_modern_transitional);
196 
197 static device_method_t vtpci_modern_methods[] = {
198 	/* Device interface. */
199 	DEVMETHOD(device_probe,			vtpci_modern_probe),
200 	DEVMETHOD(device_attach,		vtpci_modern_attach),
201 	DEVMETHOD(device_detach,		vtpci_modern_detach),
202 	DEVMETHOD(device_suspend,		vtpci_modern_suspend),
203 	DEVMETHOD(device_resume,		vtpci_modern_resume),
204 	DEVMETHOD(device_shutdown,		vtpci_modern_shutdown),
205 
206 	/* Bus interface. */
207 	DEVMETHOD(bus_driver_added,		vtpci_modern_driver_added),
208 	DEVMETHOD(bus_child_detached,		vtpci_modern_child_detached),
209 	DEVMETHOD(bus_child_pnpinfo,		virtio_child_pnpinfo),
210 	DEVMETHOD(bus_read_ivar,		vtpci_modern_read_ivar),
211 	DEVMETHOD(bus_write_ivar,		vtpci_modern_write_ivar),
212 
213 	/* VirtIO PCI interface. */
214 	DEVMETHOD(virtio_pci_read_isr,		 vtpci_modern_read_isr),
215 	DEVMETHOD(virtio_pci_get_vq_size,	 vtpci_modern_get_vq_size),
216 	DEVMETHOD(virtio_pci_get_vq_notify_off,	 vtpci_modern_get_vq_notify_off),
217 	DEVMETHOD(virtio_pci_set_vq,		 vtpci_modern_set_vq),
218 	DEVMETHOD(virtio_pci_disable_vq,	 vtpci_modern_disable_vq),
219 	DEVMETHOD(virtio_pci_register_cfg_msix,	 vtpci_modern_register_cfg_msix),
220 	DEVMETHOD(virtio_pci_register_vq_msix,	 vtpci_modern_register_vq_msix),
221 
222 	/* VirtIO bus interface. */
223 	DEVMETHOD(virtio_bus_negotiate_features,  vtpci_modern_negotiate_features),
224 	DEVMETHOD(virtio_bus_finalize_features,	  vtpci_modern_finalize_features),
225 	DEVMETHOD(virtio_bus_with_feature,	  vtpci_modern_with_feature),
226 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtpci_modern_alloc_virtqueues),
227 	DEVMETHOD(virtio_bus_setup_intr,	  vtpci_modern_setup_interrupts),
228 	DEVMETHOD(virtio_bus_stop,		  vtpci_modern_stop),
229 	DEVMETHOD(virtio_bus_reinit,		  vtpci_modern_reinit),
230 	DEVMETHOD(virtio_bus_reinit_complete,	  vtpci_modern_reinit_complete),
231 	DEVMETHOD(virtio_bus_notify_vq,		  vtpci_modern_notify_vq),
232 	DEVMETHOD(virtio_bus_config_generation,	  vtpci_modern_config_generation),
233 	DEVMETHOD(virtio_bus_read_device_config,  vtpci_modern_read_dev_config),
234 	DEVMETHOD(virtio_bus_write_device_config, vtpci_modern_write_dev_config),
235 
236 	DEVMETHOD_END
237 };
238 
239 static driver_t vtpci_modern_driver = {
240 	.name = "virtio_pci",
241 	.methods = vtpci_modern_methods,
242 	.size = sizeof(struct vtpci_modern_softc)
243 };
244 
245 DRIVER_MODULE(virtio_pci_modern, pci, vtpci_modern_driver, 0, 0);
246 
247 static int
248 vtpci_modern_probe(device_t dev)
249 {
250 	char desc[64];
251 	const char *name;
252 	uint16_t devid;
253 
254 	if (pci_get_vendor(dev) != VIRTIO_PCI_VENDORID)
255 		return (ENXIO);
256 
257 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MIN ||
258 	    pci_get_device(dev) > VIRTIO_PCI_DEVICEID_MODERN_MAX)
259 		return (ENXIO);
260 
261 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MODERN_MIN) {
262 		if (!vtpci_modern_transitional)
263 			return (ENXIO);
264 		devid = pci_get_subdevice(dev);
265 	} else
266 		devid = pci_get_device(dev) - VIRTIO_PCI_DEVICEID_MODERN_MIN;
267 
268 	if (vtpci_modern_probe_configs(dev) != 0)
269 		return (ENXIO);
270 
271 	name = virtio_device_name(devid);
272 	if (name == NULL)
273 		name = "Unknown";
274 
275 	snprintf(desc, sizeof(desc), "VirtIO PCI (modern) %s adapter", name);
276 	device_set_desc_copy(dev, desc);
277 
278 	return (BUS_PROBE_DEFAULT);
279 }
280 
281 static int
282 vtpci_modern_attach(device_t dev)
283 {
284 	struct vtpci_modern_softc *sc;
285 	int error;
286 
287 	sc = device_get_softc(dev);
288 	sc->vtpci_dev = dev;
289 	vtpci_init(&sc->vtpci_common, dev, true);
290 
291 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MODERN_MIN)
292 		sc->vtpci_devid = pci_get_subdevice(dev);
293 	else
294 		sc->vtpci_devid = pci_get_device(dev) -
295 		    VIRTIO_PCI_DEVICEID_MODERN_MIN;
296 
297 	error = vtpci_modern_map_configs(sc);
298 	if (error) {
299 		device_printf(dev, "cannot map configs\n");
300 		vtpci_modern_unmap_configs(sc);
301 		return (error);
302 	}
303 
304 	vtpci_modern_reset(sc);
305 
306 	/* Tell the host we've noticed this device. */
307 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
308 
309 	error = vtpci_add_child(&sc->vtpci_common);
310 	if (error)
311 		goto fail;
312 
313 	vtpci_modern_probe_and_attach_child(sc);
314 
315 	return (0);
316 
317 fail:
318 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_FAILED);
319 	vtpci_modern_detach(dev);
320 
321 	return (error);
322 }
323 
324 static int
325 vtpci_modern_detach(device_t dev)
326 {
327 	struct vtpci_modern_softc *sc;
328 	int error;
329 
330 	sc = device_get_softc(dev);
331 
332 	error = vtpci_delete_child(&sc->vtpci_common);
333 	if (error)
334 		return (error);
335 
336 	vtpci_modern_reset(sc);
337 	vtpci_modern_unmap_configs(sc);
338 
339 	return (0);
340 }
341 
342 static int
343 vtpci_modern_suspend(device_t dev)
344 {
345 	return (bus_generic_suspend(dev));
346 }
347 
348 static int
349 vtpci_modern_resume(device_t dev)
350 {
351 	return (bus_generic_resume(dev));
352 }
353 
354 static int
355 vtpci_modern_shutdown(device_t dev)
356 {
357 	(void) bus_generic_shutdown(dev);
358 	/* Forcibly stop the host device. */
359 	vtpci_modern_stop(dev);
360 
361 	return (0);
362 }
363 
364 static void
365 vtpci_modern_driver_added(device_t dev, driver_t *driver)
366 {
367 	vtpci_modern_probe_and_attach_child(device_get_softc(dev));
368 }
369 
370 static void
371 vtpci_modern_child_detached(device_t dev, device_t child)
372 {
373 	struct vtpci_modern_softc *sc;
374 
375 	sc = device_get_softc(dev);
376 
377 	vtpci_modern_reset(sc);
378 	vtpci_child_detached(&sc->vtpci_common);
379 
380 	/* After the reset, retell the host we've noticed this device. */
381 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
382 }
383 
384 static int
385 vtpci_modern_read_ivar(device_t dev, device_t child, int index,
386     uintptr_t *result)
387 {
388 	struct vtpci_modern_softc *sc;
389 	struct vtpci_common *cn;
390 
391 	sc = device_get_softc(dev);
392 	cn = &sc->vtpci_common;
393 
394 	if (vtpci_child_device(cn) != child)
395 		return (ENOENT);
396 
397 	switch (index) {
398 	case VIRTIO_IVAR_DEVTYPE:
399 		*result = sc->vtpci_devid;
400 		break;
401 	default:
402 		return (vtpci_read_ivar(cn, index, result));
403 	}
404 
405 	return (0);
406 }
407 
408 static int
409 vtpci_modern_write_ivar(device_t dev, device_t child, int index,
410     uintptr_t value)
411 {
412 	struct vtpci_modern_softc *sc;
413 	struct vtpci_common *cn;
414 
415 	sc = device_get_softc(dev);
416 	cn = &sc->vtpci_common;
417 
418 	if (vtpci_child_device(cn) != child)
419 		return (ENOENT);
420 
421 	switch (index) {
422 	default:
423 		return (vtpci_write_ivar(cn, index, value));
424 	}
425 
426 	return (0);
427 }
428 
429 static uint64_t
430 vtpci_modern_negotiate_features(device_t dev, uint64_t child_features)
431 {
432 	struct vtpci_modern_softc *sc;
433 	uint64_t host_features, features;
434 
435 	sc = device_get_softc(dev);
436 	host_features = vtpci_modern_read_features(sc);
437 
438 	/*
439 	 * Since the driver was added as a child of the modern PCI bus,
440 	 * always add the V1 flag.
441 	 */
442 	child_features |= VIRTIO_F_VERSION_1;
443 
444 	features = vtpci_negotiate_features(&sc->vtpci_common,
445 	    child_features, host_features);
446 	vtpci_modern_write_features(sc, features);
447 
448 	return (features);
449 }
450 
451 static int
452 vtpci_modern_finalize_features(device_t dev)
453 {
454 	struct vtpci_modern_softc *sc;
455 	uint8_t status;
456 
457 	sc = device_get_softc(dev);
458 
459 	/*
460 	 * Must re-read the status after setting it to verify the negotiated
461 	 * features were accepted by the device.
462 	 */
463 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_S_FEATURES_OK);
464 
465 	status = vtpci_modern_get_status(sc);
466 	if ((status & VIRTIO_CONFIG_S_FEATURES_OK) == 0) {
467 		device_printf(dev, "desired features were not accepted\n");
468 		return (ENOTSUP);
469 	}
470 
471 	return (0);
472 }
473 
474 static int
475 vtpci_modern_with_feature(device_t dev, uint64_t feature)
476 {
477 	struct vtpci_modern_softc *sc;
478 
479 	sc = device_get_softc(dev);
480 
481 	return (vtpci_with_feature(&sc->vtpci_common, feature));
482 }
483 
484 static uint64_t
485 vtpci_modern_read_features(struct vtpci_modern_softc *sc)
486 {
487 	uint32_t features0, features1;
488 
489 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_DFSELECT, 0);
490 	features0 = vtpci_modern_read_common_4(sc, VIRTIO_PCI_COMMON_DF);
491 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_DFSELECT, 1);
492 	features1 = vtpci_modern_read_common_4(sc, VIRTIO_PCI_COMMON_DF);
493 
494 	return (((uint64_t) features1 << 32) | features0);
495 }
496 
497 static void
498 vtpci_modern_write_features(struct vtpci_modern_softc *sc, uint64_t features)
499 {
500 	uint32_t features0, features1;
501 
502 	features0 = features;
503 	features1 = features >> 32;
504 
505 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GFSELECT, 0);
506 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GF, features0);
507 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GFSELECT, 1);
508 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GF, features1);
509 }
510 
511 static int
512 vtpci_modern_alloc_virtqueues(device_t dev, int flags, int nvqs,
513     struct vq_alloc_info *vq_info)
514 {
515 	struct vtpci_modern_softc *sc;
516 	struct vtpci_common *cn;
517 	uint16_t max_nvqs;
518 
519 	sc = device_get_softc(dev);
520 	cn = &sc->vtpci_common;
521 
522 	max_nvqs = vtpci_modern_read_common_2(sc, VIRTIO_PCI_COMMON_NUMQ);
523 	if (nvqs > max_nvqs) {
524 		device_printf(sc->vtpci_dev, "requested virtqueue count %d "
525 		    "exceeds max %d\n", nvqs, max_nvqs);
526 		return (E2BIG);
527 	}
528 
529 	return (vtpci_alloc_virtqueues(cn, flags, nvqs, vq_info));
530 }
531 
532 static int
533 vtpci_modern_setup_interrupts(device_t dev, enum intr_type type)
534 {
535 	struct vtpci_modern_softc *sc;
536 	int error;
537 
538 	sc = device_get_softc(dev);
539 
540 	error = vtpci_setup_interrupts(&sc->vtpci_common, type);
541 	if (error == 0)
542 		vtpci_modern_enable_virtqueues(sc);
543 
544 	return (error);
545 }
546 
547 static void
548 vtpci_modern_stop(device_t dev)
549 {
550 	vtpci_modern_reset(device_get_softc(dev));
551 }
552 
553 static int
554 vtpci_modern_reinit(device_t dev, uint64_t features)
555 {
556 	struct vtpci_modern_softc *sc;
557 	struct vtpci_common *cn;
558 	int error;
559 
560 	sc = device_get_softc(dev);
561 	cn = &sc->vtpci_common;
562 
563 	/*
564 	 * Redrive the device initialization. This is a bit of an abuse of
565 	 * the specification, but VirtualBox, QEMU/KVM, and BHyVe seem to
566 	 * play nice.
567 	 *
568 	 * We do not allow the host device to change from what was originally
569 	 * negotiated beyond what the guest driver changed. MSIX state should
570 	 * not change, number of virtqueues and their size remain the same, etc.
571 	 * This will need to be rethought when we want to support migration.
572 	 */
573 
574 	if (vtpci_modern_get_status(sc) != VIRTIO_CONFIG_STATUS_RESET)
575 		vtpci_modern_stop(dev);
576 
577 	/*
578 	 * Quickly drive the status through ACK and DRIVER. The device does
579 	 * not become usable again until DRIVER_OK in reinit complete.
580 	 */
581 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
582 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER);
583 
584 	/*
585 	 * TODO: Check that features are not added as to what was
586 	 * originally negotiated.
587 	 */
588 	vtpci_modern_negotiate_features(dev, features);
589 	error = vtpci_modern_finalize_features(dev);
590 	if (error) {
591 		device_printf(dev, "cannot finalize features during reinit\n");
592 		return (error);
593 	}
594 
595 	error = vtpci_reinit(cn);
596 	if (error)
597 		return (error);
598 
599 	return (0);
600 }
601 
602 static void
603 vtpci_modern_reinit_complete(device_t dev)
604 {
605 	struct vtpci_modern_softc *sc;
606 
607 	sc = device_get_softc(dev);
608 
609 	vtpci_modern_enable_virtqueues(sc);
610 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER_OK);
611 }
612 
613 static void
614 vtpci_modern_notify_vq(device_t dev, uint16_t queue, bus_size_t offset)
615 {
616 	struct vtpci_modern_softc *sc;
617 
618 	sc = device_get_softc(dev);
619 
620 	vtpci_modern_write_notify_2(sc, offset, queue);
621 }
622 
623 static uint8_t
624 vtpci_modern_get_status(struct vtpci_modern_softc *sc)
625 {
626 	return (vtpci_modern_read_common_1(sc, VIRTIO_PCI_COMMON_STATUS));
627 }
628 
629 static void
630 vtpci_modern_set_status(struct vtpci_modern_softc *sc, uint8_t status)
631 {
632 	if (status != VIRTIO_CONFIG_STATUS_RESET)
633 		status |= vtpci_modern_get_status(sc);
634 
635 	vtpci_modern_write_common_1(sc, VIRTIO_PCI_COMMON_STATUS, status);
636 }
637 
638 static int
639 vtpci_modern_config_generation(device_t dev)
640 {
641 	struct vtpci_modern_softc *sc;
642 	uint8_t gen;
643 
644 	sc = device_get_softc(dev);
645 	gen = vtpci_modern_read_common_1(sc, VIRTIO_PCI_COMMON_CFGGENERATION);
646 
647 	return (gen);
648 }
649 
650 static void
651 vtpci_modern_read_dev_config(device_t dev, bus_size_t offset, void *dst,
652     int length)
653 {
654 	struct vtpci_modern_softc *sc;
655 
656 	sc = device_get_softc(dev);
657 
658 	if (sc->vtpci_device_res_map.vtrm_map.r_size == 0) {
659 		panic("%s: attempt to read dev config but not present",
660 		    __func__);
661 	}
662 
663 	switch (length) {
664 	case 1:
665 		*(uint8_t *) dst = vtpci_modern_read_device_1(sc, offset);
666 		break;
667 	case 2:
668 		*(uint16_t *) dst = virtio_htog16(true,
669 		    vtpci_modern_read_device_2(sc, offset));
670 		break;
671 	case 4:
672 		*(uint32_t *) dst = virtio_htog32(true,
673 		    vtpci_modern_read_device_4(sc, offset));
674 		break;
675 	case 8:
676 		*(uint64_t *) dst = virtio_htog64(true,
677 		    vtpci_modern_read_device_8(sc, offset));
678 		break;
679 	default:
680 		panic("%s: device %s invalid device read length %d offset %d",
681 		    __func__, device_get_nameunit(dev), length, (int) offset);
682 	}
683 }
684 
685 static void
686 vtpci_modern_write_dev_config(device_t dev, bus_size_t offset, const void *src,
687     int length)
688 {
689 	struct vtpci_modern_softc *sc;
690 
691 	sc = device_get_softc(dev);
692 
693 	if (sc->vtpci_device_res_map.vtrm_map.r_size == 0) {
694 		panic("%s: attempt to write dev config but not present",
695 		    __func__);
696 	}
697 
698 	switch (length) {
699 	case 1:
700 		vtpci_modern_write_device_1(sc, offset, *(const uint8_t *) src);
701 		break;
702 	case 2: {
703 		uint16_t val = virtio_gtoh16(true, *(const uint16_t *) src);
704 		vtpci_modern_write_device_2(sc, offset, val);
705 		break;
706 	}
707 	case 4: {
708 		uint32_t val = virtio_gtoh32(true, *(const uint32_t *) src);
709 		vtpci_modern_write_device_4(sc, offset, val);
710 		break;
711 	}
712 	case 8: {
713 		uint64_t val = virtio_gtoh64(true, *(const uint64_t *) src);
714 		vtpci_modern_write_device_8(sc, offset, val);
715 		break;
716 	}
717 	default:
718 		panic("%s: device %s invalid device write length %d offset %d",
719 		    __func__, device_get_nameunit(dev), length, (int) offset);
720 	}
721 }
722 
723 static int
724 vtpci_modern_probe_configs(device_t dev)
725 {
726 	int error;
727 
728 	/*
729 	 * These config capabilities must be present. The DEVICE_CFG
730 	 * capability is only present if the device requires it.
731 	 */
732 
733 	error = vtpci_modern_find_cap(dev, VIRTIO_PCI_CAP_COMMON_CFG, NULL);
734 	if (error) {
735 		device_printf(dev, "cannot find COMMON_CFG capability\n");
736 		return (error);
737 	}
738 
739 	error = vtpci_modern_find_cap(dev, VIRTIO_PCI_CAP_NOTIFY_CFG, NULL);
740 	if (error) {
741 		device_printf(dev, "cannot find NOTIFY_CFG capability\n");
742 		return (error);
743 	}
744 
745 	error = vtpci_modern_find_cap(dev, VIRTIO_PCI_CAP_ISR_CFG, NULL);
746 	if (error) {
747 		device_printf(dev, "cannot find ISR_CFG capability\n");
748 		return (error);
749 	}
750 
751 	return (0);
752 }
753 
754 static int
755 vtpci_modern_find_cap(device_t dev, uint8_t cfg_type, int *cap_offset)
756 {
757 	uint32_t type, bar;
758 	int capreg, error;
759 
760 	for (error = pci_find_cap(dev, PCIY_VENDOR, &capreg);
761 	     error == 0;
762 	     error = pci_find_next_cap(dev, PCIY_VENDOR, capreg, &capreg)) {
763 
764 		type = pci_read_config(dev, capreg +
765 		    offsetof(struct virtio_pci_cap, cfg_type), 1);
766 		bar = pci_read_config(dev, capreg +
767 		    offsetof(struct virtio_pci_cap, bar), 1);
768 
769 		/* Must ignore reserved BARs. */
770 		if (bar >= VTPCI_MODERN_MAX_BARS)
771 			continue;
772 
773 		if (type == cfg_type) {
774 			if (cap_offset != NULL)
775 				*cap_offset = capreg;
776 			break;
777 		}
778 	}
779 
780 	return (error);
781 }
782 
783 static int
784 vtpci_modern_map_common_config(struct vtpci_modern_softc *sc)
785 {
786 	device_t dev;
787 	int error;
788 
789 	dev = sc->vtpci_dev;
790 
791 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_COMMON_CFG,
792 	    sizeof(struct virtio_pci_common_cfg), 4, &sc->vtpci_common_res_map);
793 	if (error) {
794 		device_printf(dev, "cannot find cap COMMON_CFG resource\n");
795 		return (error);
796 	}
797 
798 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_common_res_map);
799 	if (error) {
800 		device_printf(dev, "cannot alloc resource for COMMON_CFG\n");
801 		return (error);
802 	}
803 
804 	return (0);
805 }
806 
807 static int
808 vtpci_modern_map_notify_config(struct vtpci_modern_softc *sc)
809 {
810 	device_t dev;
811 	int cap_offset, error;
812 
813 	dev = sc->vtpci_dev;
814 
815 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_NOTIFY_CFG,
816 	    -1, 2, &sc->vtpci_notify_res_map);
817 	if (error) {
818 		device_printf(dev, "cannot find cap NOTIFY_CFG resource\n");
819 		return (error);
820 	}
821 
822 	cap_offset = sc->vtpci_notify_res_map.vtrm_cap_offset;
823 
824 	sc->vtpci_notify_offset_multiplier = pci_read_config(dev, cap_offset +
825 	    offsetof(struct virtio_pci_notify_cap, notify_off_multiplier), 4);
826 
827 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_notify_res_map);
828 	if (error) {
829 		device_printf(dev, "cannot alloc resource for NOTIFY_CFG\n");
830 		return (error);
831 	}
832 
833 	return (0);
834 }
835 
836 static int
837 vtpci_modern_map_isr_config(struct vtpci_modern_softc *sc)
838 {
839 	device_t dev;
840 	int error;
841 
842 	dev = sc->vtpci_dev;
843 
844 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_ISR_CFG,
845 	    sizeof(uint8_t), 1, &sc->vtpci_isr_res_map);
846 	if (error) {
847 		device_printf(dev, "cannot find cap ISR_CFG resource\n");
848 		return (error);
849 	}
850 
851 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_isr_res_map);
852 	if (error) {
853 		device_printf(dev, "cannot alloc resource for ISR_CFG\n");
854 		return (error);
855 	}
856 
857 	return (0);
858 }
859 
860 static int
861 vtpci_modern_map_device_config(struct vtpci_modern_softc *sc)
862 {
863 	device_t dev;
864 	int error;
865 
866 	dev = sc->vtpci_dev;
867 
868 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_DEVICE_CFG,
869 	    -1, 4, &sc->vtpci_device_res_map);
870 	if (error == ENOENT) {
871 		/* Device configuration is optional depending on device. */
872 		return (0);
873 	} else if (error) {
874 		device_printf(dev, "cannot find cap DEVICE_CFG resource\n");
875 		return (error);
876 	}
877 
878 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_device_res_map);
879 	if (error) {
880 		device_printf(dev, "cannot alloc resource for DEVICE_CFG\n");
881 		return (error);
882 	}
883 
884 	return (0);
885 }
886 
887 static int
888 vtpci_modern_map_configs(struct vtpci_modern_softc *sc)
889 {
890 	int error;
891 
892 	error = vtpci_modern_map_common_config(sc);
893 	if (error)
894 		return (error);
895 
896 	error = vtpci_modern_map_notify_config(sc);
897 	if (error)
898 		return (error);
899 
900 	error = vtpci_modern_map_isr_config(sc);
901 	if (error)
902 		return (error);
903 
904 	error = vtpci_modern_map_device_config(sc);
905 	if (error)
906 		return (error);
907 
908 	vtpci_modern_alloc_msix_resource(sc);
909 
910 	return (0);
911 }
912 
913 static void
914 vtpci_modern_unmap_configs(struct vtpci_modern_softc *sc)
915 {
916 
917 	vtpci_modern_free_resource_map(sc, &sc->vtpci_common_res_map);
918 	vtpci_modern_free_resource_map(sc, &sc->vtpci_notify_res_map);
919 	vtpci_modern_free_resource_map(sc, &sc->vtpci_isr_res_map);
920 	vtpci_modern_free_resource_map(sc, &sc->vtpci_device_res_map);
921 
922 	vtpci_modern_free_bar_resources(sc);
923 	vtpci_modern_free_msix_resource(sc);
924 
925 	sc->vtpci_notify_offset_multiplier = 0;
926 }
927 
928 static int
929 vtpci_modern_find_cap_resource(struct vtpci_modern_softc *sc, uint8_t cfg_type,
930     int min_size, int alignment, struct vtpci_modern_resource_map *res)
931 {
932 	device_t dev;
933 	int cap_offset, offset, length, error;
934 	uint8_t bar, cap_length;
935 
936 	dev = sc->vtpci_dev;
937 
938 	error = vtpci_modern_find_cap(dev, cfg_type, &cap_offset);
939 	if (error)
940 		return (error);
941 
942 	cap_length = pci_read_config(dev,
943 	    cap_offset + offsetof(struct virtio_pci_cap, cap_len), 1);
944 
945 	if (cap_length < sizeof(struct virtio_pci_cap)) {
946 		device_printf(dev, "cap %u length %d less than expected\n",
947 		    cfg_type, cap_length);
948 		return (ENXIO);
949 	}
950 
951 	bar = pci_read_config(dev,
952 	    cap_offset + offsetof(struct virtio_pci_cap, bar), 1);
953 	offset = pci_read_config(dev,
954 	    cap_offset + offsetof(struct virtio_pci_cap, offset), 4);
955 	length = pci_read_config(dev,
956 	    cap_offset + offsetof(struct virtio_pci_cap, length), 4);
957 
958 	if (min_size != -1 && length < min_size) {
959 		device_printf(dev, "cap %u struct length %d less than min %d\n",
960 		    cfg_type, length, min_size);
961 		return (ENXIO);
962 	}
963 
964 	if (offset % alignment) {
965 		device_printf(dev, "cap %u struct offset %d not aligned to %d\n",
966 		    cfg_type, offset, alignment);
967 		return (ENXIO);
968 	}
969 
970 	/* BMV: TODO Can we determine the size of the BAR here? */
971 
972 	res->vtrm_cap_offset = cap_offset;
973 	res->vtrm_bar = bar;
974 	res->vtrm_offset = offset;
975 	res->vtrm_length = length;
976 	res->vtrm_type = vtpci_modern_bar_type(sc, bar);
977 
978 	return (0);
979 }
980 
981 static int
982 vtpci_modern_bar_type(struct vtpci_modern_softc *sc, int bar)
983 {
984 	uint32_t val;
985 
986 	/*
987 	 * The BAR described by a config capability may be either an IOPORT or
988 	 * MEM, but we must know the type when calling bus_alloc_resource().
989 	 */
990 	val = pci_read_config(sc->vtpci_dev, PCIR_BAR(bar), 4);
991 	if (PCI_BAR_IO(val))
992 		return (SYS_RES_IOPORT);
993 	else
994 		return (SYS_RES_MEMORY);
995 }
996 
997 static struct resource *
998 vtpci_modern_get_bar_resource(struct vtpci_modern_softc *sc, int bar, int type)
999 {
1000 	struct resource *res;
1001 
1002 	MPASS(bar >= 0 && bar < VTPCI_MODERN_MAX_BARS);
1003 	res = sc->vtpci_bar_res[bar].vtbr_res;
1004 	MPASS(res == NULL || sc->vtpci_bar_res[bar].vtbr_type == type);
1005 
1006 	return (res);
1007 }
1008 
1009 static struct resource *
1010 vtpci_modern_alloc_bar_resource(struct vtpci_modern_softc *sc, int bar,
1011     int type)
1012 {
1013 	struct resource *res;
1014 	int rid;
1015 
1016 	MPASS(bar >= 0 && bar < VTPCI_MODERN_MAX_BARS);
1017 	MPASS(type == SYS_RES_MEMORY || type == SYS_RES_IOPORT);
1018 
1019 	res = sc->vtpci_bar_res[bar].vtbr_res;
1020 	if (res != NULL) {
1021 		MPASS(sc->vtpci_bar_res[bar].vtbr_type == type);
1022 		return (res);
1023 	}
1024 
1025 	rid = PCIR_BAR(bar);
1026 	res = bus_alloc_resource_any(sc->vtpci_dev, type, &rid,
1027 	    RF_ACTIVE | RF_UNMAPPED);
1028 	if (res != NULL) {
1029 		sc->vtpci_bar_res[bar].vtbr_res = res;
1030 		sc->vtpci_bar_res[bar].vtbr_type = type;
1031 	}
1032 
1033 	return (res);
1034 }
1035 
1036 static void
1037 vtpci_modern_free_bar_resources(struct vtpci_modern_softc *sc)
1038 {
1039 	device_t dev;
1040 	struct resource *res;
1041 	int bar, rid, type;
1042 
1043 	dev = sc->vtpci_dev;
1044 
1045 	for (bar = 0; bar < VTPCI_MODERN_MAX_BARS; bar++) {
1046 		res = sc->vtpci_bar_res[bar].vtbr_res;
1047 		type = sc->vtpci_bar_res[bar].vtbr_type;
1048 
1049 		if (res != NULL) {
1050 			rid = PCIR_BAR(bar);
1051 			bus_release_resource(dev, type, rid, res);
1052 			sc->vtpci_bar_res[bar].vtbr_res = NULL;
1053 			sc->vtpci_bar_res[bar].vtbr_type = 0;
1054 		}
1055 	}
1056 }
1057 
1058 static int
1059 vtpci_modern_alloc_resource_map(struct vtpci_modern_softc *sc,
1060     struct vtpci_modern_resource_map *map)
1061 {
1062 	struct resource_map_request req;
1063 	struct resource *res;
1064 	int type;
1065 
1066 	type = map->vtrm_type;
1067 
1068 	res = vtpci_modern_alloc_bar_resource(sc, map->vtrm_bar, type);
1069 	if (res == NULL)
1070 		return (ENXIO);
1071 
1072 	resource_init_map_request(&req);
1073 	req.offset = map->vtrm_offset;
1074 	req.length = map->vtrm_length;
1075 
1076 	return (bus_map_resource(sc->vtpci_dev, type, res, &req,
1077 	    &map->vtrm_map));
1078 }
1079 
1080 static void
1081 vtpci_modern_free_resource_map(struct vtpci_modern_softc *sc,
1082     struct vtpci_modern_resource_map *map)
1083 {
1084 	struct resource *res;
1085 	int type;
1086 
1087 	type = map->vtrm_type;
1088 	res = vtpci_modern_get_bar_resource(sc, map->vtrm_bar, type);
1089 
1090 	if (res != NULL && map->vtrm_map.r_size != 0) {
1091 		bus_unmap_resource(sc->vtpci_dev, type, res, &map->vtrm_map);
1092 		bzero(map, sizeof(struct vtpci_modern_resource_map));
1093 	}
1094 }
1095 
1096 static void
1097 vtpci_modern_alloc_msix_resource(struct vtpci_modern_softc *sc)
1098 {
1099 	device_t dev;
1100 	int bar;
1101 
1102 	dev = sc->vtpci_dev;
1103 
1104 	if (!vtpci_is_msix_available(&sc->vtpci_common) ||
1105 	    (bar = pci_msix_table_bar(dev)) == -1)
1106 		return;
1107 
1108 	/* TODO: Can this BAR be in the 0-5 range? */
1109 	sc->vtpci_msix_bar = bar;
1110 	if ((sc->vtpci_msix_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
1111 	    &bar, RF_ACTIVE)) == NULL)
1112 		device_printf(dev, "Unable to map MSIX table\n");
1113 }
1114 
1115 static void
1116 vtpci_modern_free_msix_resource(struct vtpci_modern_softc *sc)
1117 {
1118 	device_t dev;
1119 
1120 	dev = sc->vtpci_dev;
1121 
1122 	if (sc->vtpci_msix_res != NULL) {
1123 		bus_release_resource(dev, SYS_RES_MEMORY, sc->vtpci_msix_bar,
1124 		    sc->vtpci_msix_res);
1125 		sc->vtpci_msix_bar = 0;
1126 		sc->vtpci_msix_res = NULL;
1127 	}
1128 }
1129 
1130 static void
1131 vtpci_modern_probe_and_attach_child(struct vtpci_modern_softc *sc)
1132 {
1133 	device_t dev, child;
1134 
1135 	dev = sc->vtpci_dev;
1136 	child = vtpci_child_device(&sc->vtpci_common);
1137 
1138 	if (child == NULL || device_get_state(child) != DS_NOTPRESENT)
1139 		return;
1140 
1141 	if (device_probe(child) != 0)
1142 		return;
1143 
1144 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER);
1145 
1146 	if (device_attach(child) != 0) {
1147 		vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_FAILED);
1148 		/* Reset state for later attempt. */
1149 		vtpci_modern_child_detached(dev, child);
1150 	} else {
1151 		vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER_OK);
1152 		VIRTIO_ATTACH_COMPLETED(child);
1153 	}
1154 }
1155 
1156 static int
1157 vtpci_modern_register_msix(struct vtpci_modern_softc *sc, int offset,
1158     struct vtpci_interrupt *intr)
1159 {
1160 	uint16_t vector;
1161 
1162 	if (intr != NULL) {
1163 		/* Map from guest rid to host vector. */
1164 		vector = intr->vti_rid - 1;
1165 	} else
1166 		vector = VIRTIO_MSI_NO_VECTOR;
1167 
1168 	vtpci_modern_write_common_2(sc, offset, vector);
1169 	return (vtpci_modern_read_common_2(sc, offset) == vector ? 0 : ENODEV);
1170 }
1171 
1172 static int
1173 vtpci_modern_register_cfg_msix(device_t dev, struct vtpci_interrupt *intr)
1174 {
1175 	struct vtpci_modern_softc *sc;
1176 	int error;
1177 
1178 	sc = device_get_softc(dev);
1179 
1180 	error = vtpci_modern_register_msix(sc, VIRTIO_PCI_COMMON_MSIX, intr);
1181 	if (error) {
1182 		device_printf(dev,
1183 		    "unable to register config MSIX interrupt\n");
1184 		return (error);
1185 	}
1186 
1187 	return (0);
1188 }
1189 
1190 static int
1191 vtpci_modern_register_vq_msix(device_t dev, int idx,
1192     struct vtpci_interrupt *intr)
1193 {
1194 	struct vtpci_modern_softc *sc;
1195 	int error;
1196 
1197 	sc = device_get_softc(dev);
1198 
1199 	vtpci_modern_select_virtqueue(sc, idx);
1200 	error = vtpci_modern_register_msix(sc, VIRTIO_PCI_COMMON_Q_MSIX, intr);
1201 	if (error) {
1202 		device_printf(dev,
1203 		    "unable to register virtqueue MSIX interrupt\n");
1204 		return (error);
1205 	}
1206 
1207 	return (0);
1208 }
1209 
1210 static void
1211 vtpci_modern_reset(struct vtpci_modern_softc *sc)
1212 {
1213 	/*
1214 	 * Setting the status to RESET sets the host device to the
1215 	 * original, uninitialized state. Must poll the status until
1216 	 * the reset is complete.
1217 	 */
1218 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_RESET);
1219 
1220 	while (vtpci_modern_get_status(sc) != VIRTIO_CONFIG_STATUS_RESET)
1221 		cpu_spinwait();
1222 }
1223 
1224 static void
1225 vtpci_modern_select_virtqueue(struct vtpci_modern_softc *sc, int idx)
1226 {
1227 	vtpci_modern_write_common_2(sc, VIRTIO_PCI_COMMON_Q_SELECT, idx);
1228 }
1229 
1230 static uint8_t
1231 vtpci_modern_read_isr(device_t dev)
1232 {
1233 	return (vtpci_modern_read_isr_1(device_get_softc(dev), 0));
1234 }
1235 
1236 static uint16_t
1237 vtpci_modern_get_vq_size(device_t dev, int idx)
1238 {
1239 	struct vtpci_modern_softc *sc;
1240 
1241 	sc = device_get_softc(dev);
1242 
1243 	vtpci_modern_select_virtqueue(sc, idx);
1244 	return (vtpci_modern_read_common_2(sc, VIRTIO_PCI_COMMON_Q_SIZE));
1245 }
1246 
1247 static bus_size_t
1248 vtpci_modern_get_vq_notify_off(device_t dev, int idx)
1249 {
1250 	struct vtpci_modern_softc *sc;
1251 	uint16_t q_notify_off;
1252 
1253 	sc = device_get_softc(dev);
1254 
1255 	vtpci_modern_select_virtqueue(sc, idx);
1256 	q_notify_off = vtpci_modern_read_common_2(sc, VIRTIO_PCI_COMMON_Q_NOFF);
1257 
1258 	return (q_notify_off * sc->vtpci_notify_offset_multiplier);
1259 }
1260 
1261 static void
1262 vtpci_modern_set_vq(device_t dev, struct virtqueue *vq)
1263 {
1264 	struct vtpci_modern_softc *sc;
1265 
1266 	sc = device_get_softc(dev);
1267 
1268 	vtpci_modern_select_virtqueue(sc, virtqueue_index(vq));
1269 
1270 	/* BMV: Currently we never adjust the device's proposed VQ size. */
1271 	vtpci_modern_write_common_2(sc,
1272 	    VIRTIO_PCI_COMMON_Q_SIZE, virtqueue_size(vq));
1273 
1274 	vtpci_modern_write_common_8(sc,
1275 	    VIRTIO_PCI_COMMON_Q_DESCLO, virtqueue_desc_paddr(vq));
1276 	vtpci_modern_write_common_8(sc,
1277 	    VIRTIO_PCI_COMMON_Q_AVAILLO, virtqueue_avail_paddr(vq));
1278         vtpci_modern_write_common_8(sc,
1279 	    VIRTIO_PCI_COMMON_Q_USEDLO, virtqueue_used_paddr(vq));
1280 }
1281 
1282 static void
1283 vtpci_modern_disable_vq(device_t dev, int idx)
1284 {
1285 	struct vtpci_modern_softc *sc;
1286 
1287 	sc = device_get_softc(dev);
1288 
1289 	vtpci_modern_select_virtqueue(sc, idx);
1290 	vtpci_modern_write_common_8(sc, VIRTIO_PCI_COMMON_Q_DESCLO, 0ULL);
1291 	vtpci_modern_write_common_8(sc, VIRTIO_PCI_COMMON_Q_AVAILLO, 0ULL);
1292         vtpci_modern_write_common_8(sc, VIRTIO_PCI_COMMON_Q_USEDLO, 0ULL);
1293 }
1294 
1295 static void
1296 vtpci_modern_enable_virtqueues(struct vtpci_modern_softc *sc)
1297 {
1298 	int idx;
1299 
1300 	for (idx = 0; idx < sc->vtpci_common.vtpci_nvqs; idx++) {
1301 		vtpci_modern_select_virtqueue(sc, idx);
1302 		vtpci_modern_write_common_2(sc, VIRTIO_PCI_COMMON_Q_ENABLE, 1);
1303 	}
1304 }
1305 
1306 static uint8_t
1307 vtpci_modern_read_common_1(struct vtpci_modern_softc *sc, bus_size_t off)
1308 {
1309 	return (bus_read_1(&sc->vtpci_common_res_map.vtrm_map, off));
1310 }
1311 
1312 static uint16_t
1313 vtpci_modern_read_common_2(struct vtpci_modern_softc *sc, bus_size_t off)
1314 {
1315 	return virtio_htog16(true,
1316 			bus_read_2(&sc->vtpci_common_res_map.vtrm_map, off));
1317 }
1318 
1319 static uint32_t
1320 vtpci_modern_read_common_4(struct vtpci_modern_softc *sc, bus_size_t off)
1321 {
1322 	return virtio_htog32(true,
1323 			bus_read_4(&sc->vtpci_common_res_map.vtrm_map, off));
1324 }
1325 
1326 static void
1327 vtpci_modern_write_common_1(struct vtpci_modern_softc *sc, bus_size_t off,
1328     uint8_t val)
1329 {
1330 	bus_write_1(&sc->vtpci_common_res_map.vtrm_map, off, val);
1331 }
1332 
1333 static void
1334 vtpci_modern_write_common_2(struct vtpci_modern_softc *sc, bus_size_t off,
1335     uint16_t val)
1336 {
1337 	bus_write_2(&sc->vtpci_common_res_map.vtrm_map,
1338 			off, virtio_gtoh16(true, val));
1339 }
1340 
1341 static void
1342 vtpci_modern_write_common_4(struct vtpci_modern_softc *sc, bus_size_t off,
1343     uint32_t val)
1344 {
1345 	bus_write_4(&sc->vtpci_common_res_map.vtrm_map,
1346 			off, virtio_gtoh32(true, val));
1347 }
1348 
1349 static void
1350 vtpci_modern_write_common_8(struct vtpci_modern_softc *sc, bus_size_t off,
1351     uint64_t val)
1352 {
1353 	uint32_t val0, val1;
1354 
1355 	val0 = (uint32_t) val;
1356 	val1 = val >> 32;
1357 
1358 	vtpci_modern_write_common_4(sc, off, val0);
1359 	vtpci_modern_write_common_4(sc, off + 4, val1);
1360 }
1361 
1362 static void
1363 vtpci_modern_write_notify_2(struct vtpci_modern_softc *sc, bus_size_t off,
1364     uint16_t val)
1365 {
1366 	bus_write_2(&sc->vtpci_notify_res_map.vtrm_map, off, val);
1367 }
1368 
1369 static uint8_t
1370 vtpci_modern_read_isr_1(struct vtpci_modern_softc *sc, bus_size_t off)
1371 {
1372 	return (bus_read_1(&sc->vtpci_isr_res_map.vtrm_map, off));
1373 }
1374 
1375 static uint8_t
1376 vtpci_modern_read_device_1(struct vtpci_modern_softc *sc, bus_size_t off)
1377 {
1378 	return (bus_read_1(&sc->vtpci_device_res_map.vtrm_map, off));
1379 }
1380 
1381 static uint16_t
1382 vtpci_modern_read_device_2(struct vtpci_modern_softc *sc, bus_size_t off)
1383 {
1384 	return (bus_read_2(&sc->vtpci_device_res_map.vtrm_map, off));
1385 }
1386 
1387 static uint32_t
1388 vtpci_modern_read_device_4(struct vtpci_modern_softc *sc, bus_size_t off)
1389 {
1390 	return (bus_read_4(&sc->vtpci_device_res_map.vtrm_map, off));
1391 }
1392 
1393 static uint64_t
1394 vtpci_modern_read_device_8(struct vtpci_modern_softc *sc, bus_size_t off)
1395 {
1396 	device_t dev;
1397 	int gen;
1398 	uint32_t val0, val1;
1399 
1400 	dev = sc->vtpci_dev;
1401 
1402 	/*
1403 	 * Treat the 64-bit field as two 32-bit fields. Use the generation
1404 	 * to ensure a consistent read.
1405 	 */
1406 	do {
1407 		gen = vtpci_modern_config_generation(dev);
1408 		val0 = vtpci_modern_read_device_4(sc, off);
1409 		val1 = vtpci_modern_read_device_4(sc, off + 4);
1410 	} while (gen != vtpci_modern_config_generation(dev));
1411 
1412 	return (((uint64_t) val1 << 32) | val0);
1413 }
1414 
1415 static void
1416 vtpci_modern_write_device_1(struct vtpci_modern_softc *sc, bus_size_t off,
1417     uint8_t val)
1418 {
1419 	bus_write_1(&sc->vtpci_device_res_map.vtrm_map, off, val);
1420 }
1421 
1422 static void
1423 vtpci_modern_write_device_2(struct vtpci_modern_softc *sc, bus_size_t off,
1424     uint16_t val)
1425 {
1426 	bus_write_2(&sc->vtpci_device_res_map.vtrm_map, off, val);
1427 }
1428 
1429 static void
1430 vtpci_modern_write_device_4(struct vtpci_modern_softc *sc, bus_size_t off,
1431     uint32_t val)
1432 {
1433 	bus_write_4(&sc->vtpci_device_res_map.vtrm_map, off, val);
1434 }
1435 
1436 static void
1437 vtpci_modern_write_device_8(struct vtpci_modern_softc *sc, bus_size_t off,
1438     uint64_t val)
1439 {
1440 	uint32_t val0, val1;
1441 
1442 	val0 = (uint32_t) val;
1443 	val1 = val >> 32;
1444 
1445 	vtpci_modern_write_device_4(sc, off, val0);
1446 	vtpci_modern_write_device_4(sc, off + 4, val1);
1447 }
1448