xref: /freebsd/sys/dev/virtio/pci/virtio_pci_modern.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/lock.h>
36 #include <sys/kernel.h>
37 #include <sys/module.h>
38 
39 #include <machine/bus.h>
40 #include <machine/cpu.h>
41 #include <machine/resource.h>
42 #include <sys/bus.h>
43 #include <sys/rman.h>
44 
45 #include <dev/pci/pcivar.h>
46 #include <dev/pci/pcireg.h>
47 
48 #include <dev/virtio/virtio.h>
49 #include <dev/virtio/virtqueue.h>
50 #include <dev/virtio/pci/virtio_pci.h>
51 #include <dev/virtio/pci/virtio_pci_modern_var.h>
52 
53 #include "virtio_bus_if.h"
54 #include "virtio_pci_if.h"
55 #include "virtio_if.h"
56 
57 struct vtpci_modern_resource_map {
58 	struct resource_map	vtrm_map;
59 	int			vtrm_cap_offset;
60 	int			vtrm_bar;
61 	int			vtrm_offset;
62 	int			vtrm_length;
63 	int			vtrm_type;	/* SYS_RES_{MEMORY, IOPORT} */
64 };
65 
66 struct vtpci_modern_bar_resource {
67 	struct resource		*vtbr_res;
68 	int			 vtbr_type;
69 };
70 
71 struct vtpci_modern_softc {
72 	device_t			 vtpci_dev;
73 	struct vtpci_common		 vtpci_common;
74 	uint32_t			 vtpci_notify_offset_multiplier;
75 	uint16_t			 vtpci_devid;
76 	int				 vtpci_msix_bar;
77 	struct resource			*vtpci_msix_res;
78 
79 	struct vtpci_modern_resource_map vtpci_common_res_map;
80 	struct vtpci_modern_resource_map vtpci_notify_res_map;
81 	struct vtpci_modern_resource_map vtpci_isr_res_map;
82 	struct vtpci_modern_resource_map vtpci_device_res_map;
83 
84 #define VTPCI_MODERN_MAX_BARS		6
85 	struct vtpci_modern_bar_resource vtpci_bar_res[VTPCI_MODERN_MAX_BARS];
86 };
87 
88 static int	vtpci_modern_probe(device_t);
89 static int	vtpci_modern_attach(device_t);
90 static int	vtpci_modern_detach(device_t);
91 static int	vtpci_modern_suspend(device_t);
92 static int	vtpci_modern_resume(device_t);
93 static int	vtpci_modern_shutdown(device_t);
94 
95 static void	vtpci_modern_driver_added(device_t, driver_t *);
96 static void	vtpci_modern_child_detached(device_t, device_t);
97 static int	vtpci_modern_read_ivar(device_t, device_t, int, uintptr_t *);
98 static int	vtpci_modern_write_ivar(device_t, device_t, int, uintptr_t);
99 
100 static uint8_t	vtpci_modern_read_isr(device_t);
101 static uint16_t	vtpci_modern_get_vq_size(device_t, int);
102 static bus_size_t vtpci_modern_get_vq_notify_off(device_t, int);
103 static void	vtpci_modern_set_vq(device_t, struct virtqueue *);
104 static void	vtpci_modern_disable_vq(device_t, int);
105 static int	vtpci_modern_register_msix(struct vtpci_modern_softc *, int,
106 		    struct vtpci_interrupt *);
107 static int	vtpci_modern_register_cfg_msix(device_t,
108 		    struct vtpci_interrupt *);
109 static int	vtpci_modern_register_vq_msix(device_t, int idx,
110 		    struct vtpci_interrupt *);
111 
112 static uint64_t	vtpci_modern_negotiate_features(device_t, uint64_t);
113 static int	vtpci_modern_finalize_features(device_t);
114 static int	vtpci_modern_with_feature(device_t, uint64_t);
115 static int	vtpci_modern_alloc_virtqueues(device_t, int, int,
116 		    struct vq_alloc_info *);
117 static int	vtpci_modern_setup_interrupts(device_t, enum intr_type);
118 static void	vtpci_modern_stop(device_t);
119 static int	vtpci_modern_reinit(device_t, uint64_t);
120 static void	vtpci_modern_reinit_complete(device_t);
121 static void	vtpci_modern_notify_vq(device_t, uint16_t, bus_size_t);
122 static int	vtpci_modern_config_generation(device_t);
123 static void	vtpci_modern_read_dev_config(device_t, bus_size_t, void *, int);
124 static void	vtpci_modern_write_dev_config(device_t, bus_size_t, const void *, int);
125 
126 static int	vtpci_modern_probe_configs(device_t);
127 static int	vtpci_modern_find_cap(device_t, uint8_t, int *);
128 static int	vtpci_modern_map_configs(struct vtpci_modern_softc *);
129 static void	vtpci_modern_unmap_configs(struct vtpci_modern_softc *);
130 static int	vtpci_modern_find_cap_resource(struct vtpci_modern_softc *,
131 		     uint8_t, int, int, struct vtpci_modern_resource_map *);
132 static int	vtpci_modern_bar_type(struct vtpci_modern_softc *, int);
133 static struct resource *vtpci_modern_get_bar_resource(
134 		    struct vtpci_modern_softc *, int, int);
135 static struct resource *vtpci_modern_alloc_bar_resource(
136 		    struct vtpci_modern_softc *, int, int);
137 static void	vtpci_modern_free_bar_resources(struct vtpci_modern_softc *);
138 static int	vtpci_modern_alloc_resource_map(struct vtpci_modern_softc *,
139 		    struct vtpci_modern_resource_map *);
140 static void	vtpci_modern_free_resource_map(struct vtpci_modern_softc *,
141 		    struct vtpci_modern_resource_map *);
142 static void	vtpci_modern_alloc_msix_resource(struct vtpci_modern_softc *);
143 static void	vtpci_modern_free_msix_resource(struct vtpci_modern_softc *);
144 
145 static void	vtpci_modern_probe_and_attach_child(struct vtpci_modern_softc *);
146 
147 static uint64_t vtpci_modern_read_features(struct vtpci_modern_softc *);
148 static void	vtpci_modern_write_features(struct vtpci_modern_softc *,
149 		    uint64_t);
150 static void	vtpci_modern_select_virtqueue(struct vtpci_modern_softc *, int);
151 static uint8_t	vtpci_modern_get_status(struct vtpci_modern_softc *);
152 static void	vtpci_modern_set_status(struct vtpci_modern_softc *, uint8_t);
153 static void	vtpci_modern_reset(struct vtpci_modern_softc *);
154 static void	vtpci_modern_enable_virtqueues(struct vtpci_modern_softc *);
155 
156 static uint8_t	vtpci_modern_read_common_1(struct vtpci_modern_softc *,
157 		    bus_size_t);
158 static uint16_t vtpci_modern_read_common_2(struct vtpci_modern_softc *,
159 		    bus_size_t);
160 static uint32_t vtpci_modern_read_common_4(struct vtpci_modern_softc *,
161 		    bus_size_t);
162 static void	vtpci_modern_write_common_1(struct vtpci_modern_softc *,
163 		     bus_size_t, uint8_t);
164 static void	vtpci_modern_write_common_2(struct vtpci_modern_softc *,
165 		     bus_size_t, uint16_t);
166 static void	vtpci_modern_write_common_4(struct vtpci_modern_softc *,
167 		    bus_size_t, uint32_t);
168 static void	vtpci_modern_write_common_8(struct vtpci_modern_softc *,
169 		    bus_size_t, uint64_t);
170 static void	vtpci_modern_write_notify_2(struct vtpci_modern_softc *,
171 		    bus_size_t, uint16_t);
172 static uint8_t  vtpci_modern_read_isr_1(struct vtpci_modern_softc *,
173 		    bus_size_t);
174 static uint8_t	vtpci_modern_read_device_1(struct vtpci_modern_softc *,
175 		    bus_size_t);
176 static uint16_t vtpci_modern_read_device_2(struct vtpci_modern_softc *,
177 		    bus_size_t);
178 static uint32_t vtpci_modern_read_device_4(struct vtpci_modern_softc *,
179 		    bus_size_t);
180 static uint64_t vtpci_modern_read_device_8(struct vtpci_modern_softc *,
181 		    bus_size_t);
182 static void	vtpci_modern_write_device_1(struct vtpci_modern_softc *,
183 		    bus_size_t, uint8_t);
184 static void	vtpci_modern_write_device_2(struct vtpci_modern_softc *,
185 		    bus_size_t, uint16_t);
186 static void	vtpci_modern_write_device_4(struct vtpci_modern_softc *,
187 		    bus_size_t, uint32_t);
188 static void	vtpci_modern_write_device_8(struct vtpci_modern_softc *,
189 		    bus_size_t, uint64_t);
190 
191 /* Tunables. */
192 static int vtpci_modern_transitional = 0;
193 TUNABLE_INT("hw.virtio.pci.transitional", &vtpci_modern_transitional);
194 
195 static device_method_t vtpci_modern_methods[] = {
196 	/* Device interface. */
197 	DEVMETHOD(device_probe,			vtpci_modern_probe),
198 	DEVMETHOD(device_attach,		vtpci_modern_attach),
199 	DEVMETHOD(device_detach,		vtpci_modern_detach),
200 	DEVMETHOD(device_suspend,		vtpci_modern_suspend),
201 	DEVMETHOD(device_resume,		vtpci_modern_resume),
202 	DEVMETHOD(device_shutdown,		vtpci_modern_shutdown),
203 
204 	/* Bus interface. */
205 	DEVMETHOD(bus_driver_added,		vtpci_modern_driver_added),
206 	DEVMETHOD(bus_child_detached,		vtpci_modern_child_detached),
207 	DEVMETHOD(bus_child_pnpinfo,		virtio_child_pnpinfo),
208 	DEVMETHOD(bus_read_ivar,		vtpci_modern_read_ivar),
209 	DEVMETHOD(bus_write_ivar,		vtpci_modern_write_ivar),
210 
211 	/* VirtIO PCI interface. */
212 	DEVMETHOD(virtio_pci_read_isr,		 vtpci_modern_read_isr),
213 	DEVMETHOD(virtio_pci_get_vq_size,	 vtpci_modern_get_vq_size),
214 	DEVMETHOD(virtio_pci_get_vq_notify_off,	 vtpci_modern_get_vq_notify_off),
215 	DEVMETHOD(virtio_pci_set_vq,		 vtpci_modern_set_vq),
216 	DEVMETHOD(virtio_pci_disable_vq,	 vtpci_modern_disable_vq),
217 	DEVMETHOD(virtio_pci_register_cfg_msix,	 vtpci_modern_register_cfg_msix),
218 	DEVMETHOD(virtio_pci_register_vq_msix,	 vtpci_modern_register_vq_msix),
219 
220 	/* VirtIO bus interface. */
221 	DEVMETHOD(virtio_bus_negotiate_features,  vtpci_modern_negotiate_features),
222 	DEVMETHOD(virtio_bus_finalize_features,	  vtpci_modern_finalize_features),
223 	DEVMETHOD(virtio_bus_with_feature,	  vtpci_modern_with_feature),
224 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtpci_modern_alloc_virtqueues),
225 	DEVMETHOD(virtio_bus_setup_intr,	  vtpci_modern_setup_interrupts),
226 	DEVMETHOD(virtio_bus_stop,		  vtpci_modern_stop),
227 	DEVMETHOD(virtio_bus_reinit,		  vtpci_modern_reinit),
228 	DEVMETHOD(virtio_bus_reinit_complete,	  vtpci_modern_reinit_complete),
229 	DEVMETHOD(virtio_bus_notify_vq,		  vtpci_modern_notify_vq),
230 	DEVMETHOD(virtio_bus_config_generation,	  vtpci_modern_config_generation),
231 	DEVMETHOD(virtio_bus_read_device_config,  vtpci_modern_read_dev_config),
232 	DEVMETHOD(virtio_bus_write_device_config, vtpci_modern_write_dev_config),
233 
234 	DEVMETHOD_END
235 };
236 
237 static driver_t vtpci_modern_driver = {
238 	.name = "virtio_pci",
239 	.methods = vtpci_modern_methods,
240 	.size = sizeof(struct vtpci_modern_softc)
241 };
242 
243 DRIVER_MODULE(virtio_pci_modern, pci, vtpci_modern_driver, 0, 0);
244 
245 static int
246 vtpci_modern_probe(device_t dev)
247 {
248 	char desc[64];
249 	const char *name;
250 	uint16_t devid;
251 
252 	if (pci_get_vendor(dev) != VIRTIO_PCI_VENDORID)
253 		return (ENXIO);
254 
255 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MIN ||
256 	    pci_get_device(dev) > VIRTIO_PCI_DEVICEID_MODERN_MAX)
257 		return (ENXIO);
258 
259 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MODERN_MIN) {
260 		if (!vtpci_modern_transitional)
261 			return (ENXIO);
262 		devid = pci_get_subdevice(dev);
263 	} else
264 		devid = pci_get_device(dev) - VIRTIO_PCI_DEVICEID_MODERN_MIN;
265 
266 	if (vtpci_modern_probe_configs(dev) != 0)
267 		return (ENXIO);
268 
269 	name = virtio_device_name(devid);
270 	if (name == NULL)
271 		name = "Unknown";
272 
273 	snprintf(desc, sizeof(desc), "VirtIO PCI (modern) %s adapter", name);
274 	device_set_desc_copy(dev, desc);
275 
276 	return (BUS_PROBE_DEFAULT);
277 }
278 
279 static int
280 vtpci_modern_attach(device_t dev)
281 {
282 	struct vtpci_modern_softc *sc;
283 	int error;
284 
285 	sc = device_get_softc(dev);
286 	sc->vtpci_dev = dev;
287 	vtpci_init(&sc->vtpci_common, dev, true);
288 
289 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MODERN_MIN)
290 		sc->vtpci_devid = pci_get_subdevice(dev);
291 	else
292 		sc->vtpci_devid = pci_get_device(dev) -
293 		    VIRTIO_PCI_DEVICEID_MODERN_MIN;
294 
295 	error = vtpci_modern_map_configs(sc);
296 	if (error) {
297 		device_printf(dev, "cannot map configs\n");
298 		vtpci_modern_unmap_configs(sc);
299 		return (error);
300 	}
301 
302 	vtpci_modern_reset(sc);
303 
304 	/* Tell the host we've noticed this device. */
305 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
306 
307 	error = vtpci_add_child(&sc->vtpci_common);
308 	if (error)
309 		goto fail;
310 
311 	vtpci_modern_probe_and_attach_child(sc);
312 
313 	return (0);
314 
315 fail:
316 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_FAILED);
317 	vtpci_modern_detach(dev);
318 
319 	return (error);
320 }
321 
322 static int
323 vtpci_modern_detach(device_t dev)
324 {
325 	struct vtpci_modern_softc *sc;
326 	int error;
327 
328 	sc = device_get_softc(dev);
329 
330 	error = vtpci_delete_child(&sc->vtpci_common);
331 	if (error)
332 		return (error);
333 
334 	vtpci_modern_reset(sc);
335 	vtpci_modern_unmap_configs(sc);
336 
337 	return (0);
338 }
339 
340 static int
341 vtpci_modern_suspend(device_t dev)
342 {
343 	return (bus_generic_suspend(dev));
344 }
345 
346 static int
347 vtpci_modern_resume(device_t dev)
348 {
349 	return (bus_generic_resume(dev));
350 }
351 
352 static int
353 vtpci_modern_shutdown(device_t dev)
354 {
355 	(void) bus_generic_shutdown(dev);
356 	/* Forcibly stop the host device. */
357 	vtpci_modern_stop(dev);
358 
359 	return (0);
360 }
361 
362 static void
363 vtpci_modern_driver_added(device_t dev, driver_t *driver)
364 {
365 	vtpci_modern_probe_and_attach_child(device_get_softc(dev));
366 }
367 
368 static void
369 vtpci_modern_child_detached(device_t dev, device_t child)
370 {
371 	struct vtpci_modern_softc *sc;
372 
373 	sc = device_get_softc(dev);
374 
375 	vtpci_modern_reset(sc);
376 	vtpci_child_detached(&sc->vtpci_common);
377 
378 	/* After the reset, retell the host we've noticed this device. */
379 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
380 }
381 
382 static int
383 vtpci_modern_read_ivar(device_t dev, device_t child, int index,
384     uintptr_t *result)
385 {
386 	struct vtpci_modern_softc *sc;
387 	struct vtpci_common *cn;
388 
389 	sc = device_get_softc(dev);
390 	cn = &sc->vtpci_common;
391 
392 	if (vtpci_child_device(cn) != child)
393 		return (ENOENT);
394 
395 	switch (index) {
396 	case VIRTIO_IVAR_DEVTYPE:
397 		*result = sc->vtpci_devid;
398 		break;
399 	default:
400 		return (vtpci_read_ivar(cn, index, result));
401 	}
402 
403 	return (0);
404 }
405 
406 static int
407 vtpci_modern_write_ivar(device_t dev, device_t child, int index,
408     uintptr_t value)
409 {
410 	struct vtpci_modern_softc *sc;
411 	struct vtpci_common *cn;
412 
413 	sc = device_get_softc(dev);
414 	cn = &sc->vtpci_common;
415 
416 	if (vtpci_child_device(cn) != child)
417 		return (ENOENT);
418 
419 	switch (index) {
420 	default:
421 		return (vtpci_write_ivar(cn, index, value));
422 	}
423 
424 	return (0);
425 }
426 
427 static uint64_t
428 vtpci_modern_negotiate_features(device_t dev, uint64_t child_features)
429 {
430 	struct vtpci_modern_softc *sc;
431 	uint64_t host_features, features;
432 
433 	sc = device_get_softc(dev);
434 	host_features = vtpci_modern_read_features(sc);
435 
436 	/*
437 	 * Since the driver was added as a child of the modern PCI bus,
438 	 * always add the V1 flag.
439 	 */
440 	child_features |= VIRTIO_F_VERSION_1;
441 
442 	features = vtpci_negotiate_features(&sc->vtpci_common,
443 	    child_features, host_features);
444 	vtpci_modern_write_features(sc, features);
445 
446 	return (features);
447 }
448 
449 static int
450 vtpci_modern_finalize_features(device_t dev)
451 {
452 	struct vtpci_modern_softc *sc;
453 	uint8_t status;
454 
455 	sc = device_get_softc(dev);
456 
457 	/*
458 	 * Must re-read the status after setting it to verify the negotiated
459 	 * features were accepted by the device.
460 	 */
461 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_S_FEATURES_OK);
462 
463 	status = vtpci_modern_get_status(sc);
464 	if ((status & VIRTIO_CONFIG_S_FEATURES_OK) == 0) {
465 		device_printf(dev, "desired features were not accepted\n");
466 		return (ENOTSUP);
467 	}
468 
469 	return (0);
470 }
471 
472 static int
473 vtpci_modern_with_feature(device_t dev, uint64_t feature)
474 {
475 	struct vtpci_modern_softc *sc;
476 
477 	sc = device_get_softc(dev);
478 
479 	return (vtpci_with_feature(&sc->vtpci_common, feature));
480 }
481 
482 static uint64_t
483 vtpci_modern_read_features(struct vtpci_modern_softc *sc)
484 {
485 	uint32_t features0, features1;
486 
487 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_DFSELECT, 0);
488 	features0 = vtpci_modern_read_common_4(sc, VIRTIO_PCI_COMMON_DF);
489 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_DFSELECT, 1);
490 	features1 = vtpci_modern_read_common_4(sc, VIRTIO_PCI_COMMON_DF);
491 
492 	return (((uint64_t) features1 << 32) | features0);
493 }
494 
495 static void
496 vtpci_modern_write_features(struct vtpci_modern_softc *sc, uint64_t features)
497 {
498 	uint32_t features0, features1;
499 
500 	features0 = features;
501 	features1 = features >> 32;
502 
503 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GFSELECT, 0);
504 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GF, features0);
505 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GFSELECT, 1);
506 	vtpci_modern_write_common_4(sc, VIRTIO_PCI_COMMON_GF, features1);
507 }
508 
509 static int
510 vtpci_modern_alloc_virtqueues(device_t dev, int flags, int nvqs,
511     struct vq_alloc_info *vq_info)
512 {
513 	struct vtpci_modern_softc *sc;
514 	struct vtpci_common *cn;
515 	uint16_t max_nvqs;
516 
517 	sc = device_get_softc(dev);
518 	cn = &sc->vtpci_common;
519 
520 	max_nvqs = vtpci_modern_read_common_2(sc, VIRTIO_PCI_COMMON_NUMQ);
521 	if (nvqs > max_nvqs) {
522 		device_printf(sc->vtpci_dev, "requested virtqueue count %d "
523 		    "exceeds max %d\n", nvqs, max_nvqs);
524 		return (E2BIG);
525 	}
526 
527 	return (vtpci_alloc_virtqueues(cn, flags, nvqs, vq_info));
528 }
529 
530 static int
531 vtpci_modern_setup_interrupts(device_t dev, enum intr_type type)
532 {
533 	struct vtpci_modern_softc *sc;
534 	int error;
535 
536 	sc = device_get_softc(dev);
537 
538 	error = vtpci_setup_interrupts(&sc->vtpci_common, type);
539 	if (error == 0)
540 		vtpci_modern_enable_virtqueues(sc);
541 
542 	return (error);
543 }
544 
545 static void
546 vtpci_modern_stop(device_t dev)
547 {
548 	vtpci_modern_reset(device_get_softc(dev));
549 }
550 
551 static int
552 vtpci_modern_reinit(device_t dev, uint64_t features)
553 {
554 	struct vtpci_modern_softc *sc;
555 	struct vtpci_common *cn;
556 	int error;
557 
558 	sc = device_get_softc(dev);
559 	cn = &sc->vtpci_common;
560 
561 	/*
562 	 * Redrive the device initialization. This is a bit of an abuse of
563 	 * the specification, but VirtualBox, QEMU/KVM, and BHyVe seem to
564 	 * play nice.
565 	 *
566 	 * We do not allow the host device to change from what was originally
567 	 * negotiated beyond what the guest driver changed. MSIX state should
568 	 * not change, number of virtqueues and their size remain the same, etc.
569 	 * This will need to be rethought when we want to support migration.
570 	 */
571 
572 	if (vtpci_modern_get_status(sc) != VIRTIO_CONFIG_STATUS_RESET)
573 		vtpci_modern_stop(dev);
574 
575 	/*
576 	 * Quickly drive the status through ACK and DRIVER. The device does
577 	 * not become usable again until DRIVER_OK in reinit complete.
578 	 */
579 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
580 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER);
581 
582 	/*
583 	 * TODO: Check that features are not added as to what was
584 	 * originally negotiated.
585 	 */
586 	vtpci_modern_negotiate_features(dev, features);
587 	error = vtpci_modern_finalize_features(dev);
588 	if (error) {
589 		device_printf(dev, "cannot finalize features during reinit\n");
590 		return (error);
591 	}
592 
593 	error = vtpci_reinit(cn);
594 	if (error)
595 		return (error);
596 
597 	return (0);
598 }
599 
600 static void
601 vtpci_modern_reinit_complete(device_t dev)
602 {
603 	struct vtpci_modern_softc *sc;
604 
605 	sc = device_get_softc(dev);
606 
607 	vtpci_modern_enable_virtqueues(sc);
608 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER_OK);
609 }
610 
611 static void
612 vtpci_modern_notify_vq(device_t dev, uint16_t queue, bus_size_t offset)
613 {
614 	struct vtpci_modern_softc *sc;
615 
616 	sc = device_get_softc(dev);
617 
618 	vtpci_modern_write_notify_2(sc, offset, queue);
619 }
620 
621 static uint8_t
622 vtpci_modern_get_status(struct vtpci_modern_softc *sc)
623 {
624 	return (vtpci_modern_read_common_1(sc, VIRTIO_PCI_COMMON_STATUS));
625 }
626 
627 static void
628 vtpci_modern_set_status(struct vtpci_modern_softc *sc, uint8_t status)
629 {
630 	if (status != VIRTIO_CONFIG_STATUS_RESET)
631 		status |= vtpci_modern_get_status(sc);
632 
633 	vtpci_modern_write_common_1(sc, VIRTIO_PCI_COMMON_STATUS, status);
634 }
635 
636 static int
637 vtpci_modern_config_generation(device_t dev)
638 {
639 	struct vtpci_modern_softc *sc;
640 	uint8_t gen;
641 
642 	sc = device_get_softc(dev);
643 	gen = vtpci_modern_read_common_1(sc, VIRTIO_PCI_COMMON_CFGGENERATION);
644 
645 	return (gen);
646 }
647 
648 static void
649 vtpci_modern_read_dev_config(device_t dev, bus_size_t offset, void *dst,
650     int length)
651 {
652 	struct vtpci_modern_softc *sc;
653 
654 	sc = device_get_softc(dev);
655 
656 	if (sc->vtpci_device_res_map.vtrm_map.r_size == 0) {
657 		panic("%s: attempt to read dev config but not present",
658 		    __func__);
659 	}
660 
661 	switch (length) {
662 	case 1:
663 		*(uint8_t *) dst = vtpci_modern_read_device_1(sc, offset);
664 		break;
665 	case 2:
666 		*(uint16_t *) dst = virtio_htog16(true,
667 		    vtpci_modern_read_device_2(sc, offset));
668 		break;
669 	case 4:
670 		*(uint32_t *) dst = virtio_htog32(true,
671 		    vtpci_modern_read_device_4(sc, offset));
672 		break;
673 	case 8:
674 		*(uint64_t *) dst = virtio_htog64(true,
675 		    vtpci_modern_read_device_8(sc, offset));
676 		break;
677 	default:
678 		panic("%s: device %s invalid device read length %d offset %d",
679 		    __func__, device_get_nameunit(dev), length, (int) offset);
680 	}
681 }
682 
683 static void
684 vtpci_modern_write_dev_config(device_t dev, bus_size_t offset, const void *src,
685     int length)
686 {
687 	struct vtpci_modern_softc *sc;
688 
689 	sc = device_get_softc(dev);
690 
691 	if (sc->vtpci_device_res_map.vtrm_map.r_size == 0) {
692 		panic("%s: attempt to write dev config but not present",
693 		    __func__);
694 	}
695 
696 	switch (length) {
697 	case 1:
698 		vtpci_modern_write_device_1(sc, offset, *(const uint8_t *) src);
699 		break;
700 	case 2: {
701 		uint16_t val = virtio_gtoh16(true, *(const uint16_t *) src);
702 		vtpci_modern_write_device_2(sc, offset, val);
703 		break;
704 	}
705 	case 4: {
706 		uint32_t val = virtio_gtoh32(true, *(const uint32_t *) src);
707 		vtpci_modern_write_device_4(sc, offset, val);
708 		break;
709 	}
710 	case 8: {
711 		uint64_t val = virtio_gtoh64(true, *(const uint64_t *) src);
712 		vtpci_modern_write_device_8(sc, offset, val);
713 		break;
714 	}
715 	default:
716 		panic("%s: device %s invalid device write length %d offset %d",
717 		    __func__, device_get_nameunit(dev), length, (int) offset);
718 	}
719 }
720 
721 static int
722 vtpci_modern_probe_configs(device_t dev)
723 {
724 	int error;
725 
726 	/*
727 	 * These config capabilities must be present. The DEVICE_CFG
728 	 * capability is only present if the device requires it.
729 	 */
730 
731 	error = vtpci_modern_find_cap(dev, VIRTIO_PCI_CAP_COMMON_CFG, NULL);
732 	if (error) {
733 		device_printf(dev, "cannot find COMMON_CFG capability\n");
734 		return (error);
735 	}
736 
737 	error = vtpci_modern_find_cap(dev, VIRTIO_PCI_CAP_NOTIFY_CFG, NULL);
738 	if (error) {
739 		device_printf(dev, "cannot find NOTIFY_CFG capability\n");
740 		return (error);
741 	}
742 
743 	error = vtpci_modern_find_cap(dev, VIRTIO_PCI_CAP_ISR_CFG, NULL);
744 	if (error) {
745 		device_printf(dev, "cannot find ISR_CFG capability\n");
746 		return (error);
747 	}
748 
749 	return (0);
750 }
751 
752 static int
753 vtpci_modern_find_cap(device_t dev, uint8_t cfg_type, int *cap_offset)
754 {
755 	uint32_t type, bar;
756 	int capreg, error;
757 
758 	for (error = pci_find_cap(dev, PCIY_VENDOR, &capreg);
759 	     error == 0;
760 	     error = pci_find_next_cap(dev, PCIY_VENDOR, capreg, &capreg)) {
761 
762 		type = pci_read_config(dev, capreg +
763 		    offsetof(struct virtio_pci_cap, cfg_type), 1);
764 		bar = pci_read_config(dev, capreg +
765 		    offsetof(struct virtio_pci_cap, bar), 1);
766 
767 		/* Must ignore reserved BARs. */
768 		if (bar >= VTPCI_MODERN_MAX_BARS)
769 			continue;
770 
771 		if (type == cfg_type) {
772 			if (cap_offset != NULL)
773 				*cap_offset = capreg;
774 			break;
775 		}
776 	}
777 
778 	return (error);
779 }
780 
781 static int
782 vtpci_modern_map_common_config(struct vtpci_modern_softc *sc)
783 {
784 	device_t dev;
785 	int error;
786 
787 	dev = sc->vtpci_dev;
788 
789 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_COMMON_CFG,
790 	    sizeof(struct virtio_pci_common_cfg), 4, &sc->vtpci_common_res_map);
791 	if (error) {
792 		device_printf(dev, "cannot find cap COMMON_CFG resource\n");
793 		return (error);
794 	}
795 
796 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_common_res_map);
797 	if (error) {
798 		device_printf(dev, "cannot alloc resource for COMMON_CFG\n");
799 		return (error);
800 	}
801 
802 	return (0);
803 }
804 
805 static int
806 vtpci_modern_map_notify_config(struct vtpci_modern_softc *sc)
807 {
808 	device_t dev;
809 	int cap_offset, error;
810 
811 	dev = sc->vtpci_dev;
812 
813 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_NOTIFY_CFG,
814 	    -1, 2, &sc->vtpci_notify_res_map);
815 	if (error) {
816 		device_printf(dev, "cannot find cap NOTIFY_CFG resource\n");
817 		return (error);
818 	}
819 
820 	cap_offset = sc->vtpci_notify_res_map.vtrm_cap_offset;
821 
822 	sc->vtpci_notify_offset_multiplier = pci_read_config(dev, cap_offset +
823 	    offsetof(struct virtio_pci_notify_cap, notify_off_multiplier), 4);
824 
825 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_notify_res_map);
826 	if (error) {
827 		device_printf(dev, "cannot alloc resource for NOTIFY_CFG\n");
828 		return (error);
829 	}
830 
831 	return (0);
832 }
833 
834 static int
835 vtpci_modern_map_isr_config(struct vtpci_modern_softc *sc)
836 {
837 	device_t dev;
838 	int error;
839 
840 	dev = sc->vtpci_dev;
841 
842 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_ISR_CFG,
843 	    sizeof(uint8_t), 1, &sc->vtpci_isr_res_map);
844 	if (error) {
845 		device_printf(dev, "cannot find cap ISR_CFG resource\n");
846 		return (error);
847 	}
848 
849 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_isr_res_map);
850 	if (error) {
851 		device_printf(dev, "cannot alloc resource for ISR_CFG\n");
852 		return (error);
853 	}
854 
855 	return (0);
856 }
857 
858 static int
859 vtpci_modern_map_device_config(struct vtpci_modern_softc *sc)
860 {
861 	device_t dev;
862 	int error;
863 
864 	dev = sc->vtpci_dev;
865 
866 	error = vtpci_modern_find_cap_resource(sc, VIRTIO_PCI_CAP_DEVICE_CFG,
867 	    -1, 4, &sc->vtpci_device_res_map);
868 	if (error == ENOENT) {
869 		/* Device configuration is optional depending on device. */
870 		return (0);
871 	} else if (error) {
872 		device_printf(dev, "cannot find cap DEVICE_CFG resource\n");
873 		return (error);
874 	}
875 
876 	error = vtpci_modern_alloc_resource_map(sc, &sc->vtpci_device_res_map);
877 	if (error) {
878 		device_printf(dev, "cannot alloc resource for DEVICE_CFG\n");
879 		return (error);
880 	}
881 
882 	return (0);
883 }
884 
885 static int
886 vtpci_modern_map_configs(struct vtpci_modern_softc *sc)
887 {
888 	int error;
889 
890 	error = vtpci_modern_map_common_config(sc);
891 	if (error)
892 		return (error);
893 
894 	error = vtpci_modern_map_notify_config(sc);
895 	if (error)
896 		return (error);
897 
898 	error = vtpci_modern_map_isr_config(sc);
899 	if (error)
900 		return (error);
901 
902 	error = vtpci_modern_map_device_config(sc);
903 	if (error)
904 		return (error);
905 
906 	vtpci_modern_alloc_msix_resource(sc);
907 
908 	return (0);
909 }
910 
911 static void
912 vtpci_modern_unmap_configs(struct vtpci_modern_softc *sc)
913 {
914 
915 	vtpci_modern_free_resource_map(sc, &sc->vtpci_common_res_map);
916 	vtpci_modern_free_resource_map(sc, &sc->vtpci_notify_res_map);
917 	vtpci_modern_free_resource_map(sc, &sc->vtpci_isr_res_map);
918 	vtpci_modern_free_resource_map(sc, &sc->vtpci_device_res_map);
919 
920 	vtpci_modern_free_bar_resources(sc);
921 	vtpci_modern_free_msix_resource(sc);
922 
923 	sc->vtpci_notify_offset_multiplier = 0;
924 }
925 
926 static int
927 vtpci_modern_find_cap_resource(struct vtpci_modern_softc *sc, uint8_t cfg_type,
928     int min_size, int alignment, struct vtpci_modern_resource_map *res)
929 {
930 	device_t dev;
931 	int cap_offset, offset, length, error;
932 	uint8_t bar, cap_length;
933 
934 	dev = sc->vtpci_dev;
935 
936 	error = vtpci_modern_find_cap(dev, cfg_type, &cap_offset);
937 	if (error)
938 		return (error);
939 
940 	cap_length = pci_read_config(dev,
941 	    cap_offset + offsetof(struct virtio_pci_cap, cap_len), 1);
942 
943 	if (cap_length < sizeof(struct virtio_pci_cap)) {
944 		device_printf(dev, "cap %u length %d less than expected\n",
945 		    cfg_type, cap_length);
946 		return (ENXIO);
947 	}
948 
949 	bar = pci_read_config(dev,
950 	    cap_offset + offsetof(struct virtio_pci_cap, bar), 1);
951 	offset = pci_read_config(dev,
952 	    cap_offset + offsetof(struct virtio_pci_cap, offset), 4);
953 	length = pci_read_config(dev,
954 	    cap_offset + offsetof(struct virtio_pci_cap, length), 4);
955 
956 	if (min_size != -1 && length < min_size) {
957 		device_printf(dev, "cap %u struct length %d less than min %d\n",
958 		    cfg_type, length, min_size);
959 		return (ENXIO);
960 	}
961 
962 	if (offset % alignment) {
963 		device_printf(dev, "cap %u struct offset %d not aligned to %d\n",
964 		    cfg_type, offset, alignment);
965 		return (ENXIO);
966 	}
967 
968 	/* BMV: TODO Can we determine the size of the BAR here? */
969 
970 	res->vtrm_cap_offset = cap_offset;
971 	res->vtrm_bar = bar;
972 	res->vtrm_offset = offset;
973 	res->vtrm_length = length;
974 	res->vtrm_type = vtpci_modern_bar_type(sc, bar);
975 
976 	return (0);
977 }
978 
979 static int
980 vtpci_modern_bar_type(struct vtpci_modern_softc *sc, int bar)
981 {
982 	uint32_t val;
983 
984 	/*
985 	 * The BAR described by a config capability may be either an IOPORT or
986 	 * MEM, but we must know the type when calling bus_alloc_resource().
987 	 */
988 	val = pci_read_config(sc->vtpci_dev, PCIR_BAR(bar), 4);
989 	if (PCI_BAR_IO(val))
990 		return (SYS_RES_IOPORT);
991 	else
992 		return (SYS_RES_MEMORY);
993 }
994 
995 static struct resource *
996 vtpci_modern_get_bar_resource(struct vtpci_modern_softc *sc, int bar, int type)
997 {
998 	struct resource *res;
999 
1000 	MPASS(bar >= 0 && bar < VTPCI_MODERN_MAX_BARS);
1001 	res = sc->vtpci_bar_res[bar].vtbr_res;
1002 	MPASS(res == NULL || sc->vtpci_bar_res[bar].vtbr_type == type);
1003 
1004 	return (res);
1005 }
1006 
1007 static struct resource *
1008 vtpci_modern_alloc_bar_resource(struct vtpci_modern_softc *sc, int bar,
1009     int type)
1010 {
1011 	struct resource *res;
1012 	int rid;
1013 
1014 	MPASS(bar >= 0 && bar < VTPCI_MODERN_MAX_BARS);
1015 	MPASS(type == SYS_RES_MEMORY || type == SYS_RES_IOPORT);
1016 
1017 	res = sc->vtpci_bar_res[bar].vtbr_res;
1018 	if (res != NULL) {
1019 		MPASS(sc->vtpci_bar_res[bar].vtbr_type == type);
1020 		return (res);
1021 	}
1022 
1023 	rid = PCIR_BAR(bar);
1024 	res = bus_alloc_resource_any(sc->vtpci_dev, type, &rid,
1025 	    RF_ACTIVE | RF_UNMAPPED);
1026 	if (res != NULL) {
1027 		sc->vtpci_bar_res[bar].vtbr_res = res;
1028 		sc->vtpci_bar_res[bar].vtbr_type = type;
1029 	}
1030 
1031 	return (res);
1032 }
1033 
1034 static void
1035 vtpci_modern_free_bar_resources(struct vtpci_modern_softc *sc)
1036 {
1037 	device_t dev;
1038 	struct resource *res;
1039 	int bar, rid, type;
1040 
1041 	dev = sc->vtpci_dev;
1042 
1043 	for (bar = 0; bar < VTPCI_MODERN_MAX_BARS; bar++) {
1044 		res = sc->vtpci_bar_res[bar].vtbr_res;
1045 		type = sc->vtpci_bar_res[bar].vtbr_type;
1046 
1047 		if (res != NULL) {
1048 			rid = PCIR_BAR(bar);
1049 			bus_release_resource(dev, type, rid, res);
1050 			sc->vtpci_bar_res[bar].vtbr_res = NULL;
1051 			sc->vtpci_bar_res[bar].vtbr_type = 0;
1052 		}
1053 	}
1054 }
1055 
1056 static int
1057 vtpci_modern_alloc_resource_map(struct vtpci_modern_softc *sc,
1058     struct vtpci_modern_resource_map *map)
1059 {
1060 	struct resource_map_request req;
1061 	struct resource *res;
1062 	int type;
1063 
1064 	type = map->vtrm_type;
1065 
1066 	res = vtpci_modern_alloc_bar_resource(sc, map->vtrm_bar, type);
1067 	if (res == NULL)
1068 		return (ENXIO);
1069 
1070 	resource_init_map_request(&req);
1071 	req.offset = map->vtrm_offset;
1072 	req.length = map->vtrm_length;
1073 
1074 	return (bus_map_resource(sc->vtpci_dev, type, res, &req,
1075 	    &map->vtrm_map));
1076 }
1077 
1078 static void
1079 vtpci_modern_free_resource_map(struct vtpci_modern_softc *sc,
1080     struct vtpci_modern_resource_map *map)
1081 {
1082 	struct resource *res;
1083 	int type;
1084 
1085 	type = map->vtrm_type;
1086 	res = vtpci_modern_get_bar_resource(sc, map->vtrm_bar, type);
1087 
1088 	if (res != NULL && map->vtrm_map.r_size != 0) {
1089 		bus_unmap_resource(sc->vtpci_dev, type, res, &map->vtrm_map);
1090 		bzero(map, sizeof(struct vtpci_modern_resource_map));
1091 	}
1092 }
1093 
1094 static void
1095 vtpci_modern_alloc_msix_resource(struct vtpci_modern_softc *sc)
1096 {
1097 	device_t dev;
1098 	int bar;
1099 
1100 	dev = sc->vtpci_dev;
1101 
1102 	if (!vtpci_is_msix_available(&sc->vtpci_common) ||
1103 	    (bar = pci_msix_table_bar(dev)) == -1)
1104 		return;
1105 
1106 	/* TODO: Can this BAR be in the 0-5 range? */
1107 	sc->vtpci_msix_bar = bar;
1108 	if ((sc->vtpci_msix_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
1109 	    &bar, RF_ACTIVE)) == NULL)
1110 		device_printf(dev, "Unable to map MSIX table\n");
1111 }
1112 
1113 static void
1114 vtpci_modern_free_msix_resource(struct vtpci_modern_softc *sc)
1115 {
1116 	device_t dev;
1117 
1118 	dev = sc->vtpci_dev;
1119 
1120 	if (sc->vtpci_msix_res != NULL) {
1121 		bus_release_resource(dev, SYS_RES_MEMORY, sc->vtpci_msix_bar,
1122 		    sc->vtpci_msix_res);
1123 		sc->vtpci_msix_bar = 0;
1124 		sc->vtpci_msix_res = NULL;
1125 	}
1126 }
1127 
1128 static void
1129 vtpci_modern_probe_and_attach_child(struct vtpci_modern_softc *sc)
1130 {
1131 	device_t dev, child;
1132 
1133 	dev = sc->vtpci_dev;
1134 	child = vtpci_child_device(&sc->vtpci_common);
1135 
1136 	if (child == NULL || device_get_state(child) != DS_NOTPRESENT)
1137 		return;
1138 
1139 	if (device_probe(child) != 0)
1140 		return;
1141 
1142 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER);
1143 
1144 	if (device_attach(child) != 0) {
1145 		vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_FAILED);
1146 		/* Reset state for later attempt. */
1147 		vtpci_modern_child_detached(dev, child);
1148 	} else {
1149 		vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER_OK);
1150 		VIRTIO_ATTACH_COMPLETED(child);
1151 	}
1152 }
1153 
1154 static int
1155 vtpci_modern_register_msix(struct vtpci_modern_softc *sc, int offset,
1156     struct vtpci_interrupt *intr)
1157 {
1158 	uint16_t vector;
1159 
1160 	if (intr != NULL) {
1161 		/* Map from guest rid to host vector. */
1162 		vector = intr->vti_rid - 1;
1163 	} else
1164 		vector = VIRTIO_MSI_NO_VECTOR;
1165 
1166 	vtpci_modern_write_common_2(sc, offset, vector);
1167 	return (vtpci_modern_read_common_2(sc, offset) == vector ? 0 : ENODEV);
1168 }
1169 
1170 static int
1171 vtpci_modern_register_cfg_msix(device_t dev, struct vtpci_interrupt *intr)
1172 {
1173 	struct vtpci_modern_softc *sc;
1174 	int error;
1175 
1176 	sc = device_get_softc(dev);
1177 
1178 	error = vtpci_modern_register_msix(sc, VIRTIO_PCI_COMMON_MSIX, intr);
1179 	if (error) {
1180 		device_printf(dev,
1181 		    "unable to register config MSIX interrupt\n");
1182 		return (error);
1183 	}
1184 
1185 	return (0);
1186 }
1187 
1188 static int
1189 vtpci_modern_register_vq_msix(device_t dev, int idx,
1190     struct vtpci_interrupt *intr)
1191 {
1192 	struct vtpci_modern_softc *sc;
1193 	int error;
1194 
1195 	sc = device_get_softc(dev);
1196 
1197 	vtpci_modern_select_virtqueue(sc, idx);
1198 	error = vtpci_modern_register_msix(sc, VIRTIO_PCI_COMMON_Q_MSIX, intr);
1199 	if (error) {
1200 		device_printf(dev,
1201 		    "unable to register virtqueue MSIX interrupt\n");
1202 		return (error);
1203 	}
1204 
1205 	return (0);
1206 }
1207 
1208 static void
1209 vtpci_modern_reset(struct vtpci_modern_softc *sc)
1210 {
1211 	/*
1212 	 * Setting the status to RESET sets the host device to the
1213 	 * original, uninitialized state. Must poll the status until
1214 	 * the reset is complete.
1215 	 */
1216 	vtpci_modern_set_status(sc, VIRTIO_CONFIG_STATUS_RESET);
1217 
1218 	while (vtpci_modern_get_status(sc) != VIRTIO_CONFIG_STATUS_RESET)
1219 		cpu_spinwait();
1220 }
1221 
1222 static void
1223 vtpci_modern_select_virtqueue(struct vtpci_modern_softc *sc, int idx)
1224 {
1225 	vtpci_modern_write_common_2(sc, VIRTIO_PCI_COMMON_Q_SELECT, idx);
1226 }
1227 
1228 static uint8_t
1229 vtpci_modern_read_isr(device_t dev)
1230 {
1231 	return (vtpci_modern_read_isr_1(device_get_softc(dev), 0));
1232 }
1233 
1234 static uint16_t
1235 vtpci_modern_get_vq_size(device_t dev, int idx)
1236 {
1237 	struct vtpci_modern_softc *sc;
1238 
1239 	sc = device_get_softc(dev);
1240 
1241 	vtpci_modern_select_virtqueue(sc, idx);
1242 	return (vtpci_modern_read_common_2(sc, VIRTIO_PCI_COMMON_Q_SIZE));
1243 }
1244 
1245 static bus_size_t
1246 vtpci_modern_get_vq_notify_off(device_t dev, int idx)
1247 {
1248 	struct vtpci_modern_softc *sc;
1249 	uint16_t q_notify_off;
1250 
1251 	sc = device_get_softc(dev);
1252 
1253 	vtpci_modern_select_virtqueue(sc, idx);
1254 	q_notify_off = vtpci_modern_read_common_2(sc, VIRTIO_PCI_COMMON_Q_NOFF);
1255 
1256 	return (q_notify_off * sc->vtpci_notify_offset_multiplier);
1257 }
1258 
1259 static void
1260 vtpci_modern_set_vq(device_t dev, struct virtqueue *vq)
1261 {
1262 	struct vtpci_modern_softc *sc;
1263 
1264 	sc = device_get_softc(dev);
1265 
1266 	vtpci_modern_select_virtqueue(sc, virtqueue_index(vq));
1267 
1268 	/* BMV: Currently we never adjust the device's proposed VQ size. */
1269 	vtpci_modern_write_common_2(sc,
1270 	    VIRTIO_PCI_COMMON_Q_SIZE, virtqueue_size(vq));
1271 
1272 	vtpci_modern_write_common_8(sc,
1273 	    VIRTIO_PCI_COMMON_Q_DESCLO, virtqueue_desc_paddr(vq));
1274 	vtpci_modern_write_common_8(sc,
1275 	    VIRTIO_PCI_COMMON_Q_AVAILLO, virtqueue_avail_paddr(vq));
1276         vtpci_modern_write_common_8(sc,
1277 	    VIRTIO_PCI_COMMON_Q_USEDLO, virtqueue_used_paddr(vq));
1278 }
1279 
1280 static void
1281 vtpci_modern_disable_vq(device_t dev, int idx)
1282 {
1283 	struct vtpci_modern_softc *sc;
1284 
1285 	sc = device_get_softc(dev);
1286 
1287 	vtpci_modern_select_virtqueue(sc, idx);
1288 	vtpci_modern_write_common_8(sc, VIRTIO_PCI_COMMON_Q_DESCLO, 0ULL);
1289 	vtpci_modern_write_common_8(sc, VIRTIO_PCI_COMMON_Q_AVAILLO, 0ULL);
1290         vtpci_modern_write_common_8(sc, VIRTIO_PCI_COMMON_Q_USEDLO, 0ULL);
1291 }
1292 
1293 static void
1294 vtpci_modern_enable_virtqueues(struct vtpci_modern_softc *sc)
1295 {
1296 	int idx;
1297 
1298 	for (idx = 0; idx < sc->vtpci_common.vtpci_nvqs; idx++) {
1299 		vtpci_modern_select_virtqueue(sc, idx);
1300 		vtpci_modern_write_common_2(sc, VIRTIO_PCI_COMMON_Q_ENABLE, 1);
1301 	}
1302 }
1303 
1304 static uint8_t
1305 vtpci_modern_read_common_1(struct vtpci_modern_softc *sc, bus_size_t off)
1306 {
1307 	return (bus_read_1(&sc->vtpci_common_res_map.vtrm_map, off));
1308 }
1309 
1310 static uint16_t
1311 vtpci_modern_read_common_2(struct vtpci_modern_softc *sc, bus_size_t off)
1312 {
1313 	return virtio_htog16(true,
1314 			bus_read_2(&sc->vtpci_common_res_map.vtrm_map, off));
1315 }
1316 
1317 static uint32_t
1318 vtpci_modern_read_common_4(struct vtpci_modern_softc *sc, bus_size_t off)
1319 {
1320 	return virtio_htog32(true,
1321 			bus_read_4(&sc->vtpci_common_res_map.vtrm_map, off));
1322 }
1323 
1324 static void
1325 vtpci_modern_write_common_1(struct vtpci_modern_softc *sc, bus_size_t off,
1326     uint8_t val)
1327 {
1328 	bus_write_1(&sc->vtpci_common_res_map.vtrm_map, off, val);
1329 }
1330 
1331 static void
1332 vtpci_modern_write_common_2(struct vtpci_modern_softc *sc, bus_size_t off,
1333     uint16_t val)
1334 {
1335 	bus_write_2(&sc->vtpci_common_res_map.vtrm_map,
1336 			off, virtio_gtoh16(true, val));
1337 }
1338 
1339 static void
1340 vtpci_modern_write_common_4(struct vtpci_modern_softc *sc, bus_size_t off,
1341     uint32_t val)
1342 {
1343 	bus_write_4(&sc->vtpci_common_res_map.vtrm_map,
1344 			off, virtio_gtoh32(true, val));
1345 }
1346 
1347 static void
1348 vtpci_modern_write_common_8(struct vtpci_modern_softc *sc, bus_size_t off,
1349     uint64_t val)
1350 {
1351 	uint32_t val0, val1;
1352 
1353 	val0 = (uint32_t) val;
1354 	val1 = val >> 32;
1355 
1356 	vtpci_modern_write_common_4(sc, off, val0);
1357 	vtpci_modern_write_common_4(sc, off + 4, val1);
1358 }
1359 
1360 static void
1361 vtpci_modern_write_notify_2(struct vtpci_modern_softc *sc, bus_size_t off,
1362     uint16_t val)
1363 {
1364 	bus_write_2(&sc->vtpci_notify_res_map.vtrm_map, off, val);
1365 }
1366 
1367 static uint8_t
1368 vtpci_modern_read_isr_1(struct vtpci_modern_softc *sc, bus_size_t off)
1369 {
1370 	return (bus_read_1(&sc->vtpci_isr_res_map.vtrm_map, off));
1371 }
1372 
1373 static uint8_t
1374 vtpci_modern_read_device_1(struct vtpci_modern_softc *sc, bus_size_t off)
1375 {
1376 	return (bus_read_1(&sc->vtpci_device_res_map.vtrm_map, off));
1377 }
1378 
1379 static uint16_t
1380 vtpci_modern_read_device_2(struct vtpci_modern_softc *sc, bus_size_t off)
1381 {
1382 	return (bus_read_2(&sc->vtpci_device_res_map.vtrm_map, off));
1383 }
1384 
1385 static uint32_t
1386 vtpci_modern_read_device_4(struct vtpci_modern_softc *sc, bus_size_t off)
1387 {
1388 	return (bus_read_4(&sc->vtpci_device_res_map.vtrm_map, off));
1389 }
1390 
1391 static uint64_t
1392 vtpci_modern_read_device_8(struct vtpci_modern_softc *sc, bus_size_t off)
1393 {
1394 	device_t dev;
1395 	int gen;
1396 	uint32_t val0, val1;
1397 
1398 	dev = sc->vtpci_dev;
1399 
1400 	/*
1401 	 * Treat the 64-bit field as two 32-bit fields. Use the generation
1402 	 * to ensure a consistent read.
1403 	 */
1404 	do {
1405 		gen = vtpci_modern_config_generation(dev);
1406 		val0 = vtpci_modern_read_device_4(sc, off);
1407 		val1 = vtpci_modern_read_device_4(sc, off + 4);
1408 	} while (gen != vtpci_modern_config_generation(dev));
1409 
1410 	return (((uint64_t) val1 << 32) | val0);
1411 }
1412 
1413 static void
1414 vtpci_modern_write_device_1(struct vtpci_modern_softc *sc, bus_size_t off,
1415     uint8_t val)
1416 {
1417 	bus_write_1(&sc->vtpci_device_res_map.vtrm_map, off, val);
1418 }
1419 
1420 static void
1421 vtpci_modern_write_device_2(struct vtpci_modern_softc *sc, bus_size_t off,
1422     uint16_t val)
1423 {
1424 	bus_write_2(&sc->vtpci_device_res_map.vtrm_map, off, val);
1425 }
1426 
1427 static void
1428 vtpci_modern_write_device_4(struct vtpci_modern_softc *sc, bus_size_t off,
1429     uint32_t val)
1430 {
1431 	bus_write_4(&sc->vtpci_device_res_map.vtrm_map, off, val);
1432 }
1433 
1434 static void
1435 vtpci_modern_write_device_8(struct vtpci_modern_softc *sc, bus_size_t off,
1436     uint64_t val)
1437 {
1438 	uint32_t val0, val1;
1439 
1440 	val0 = (uint32_t) val;
1441 	val1 = val >> 32;
1442 
1443 	vtpci_modern_write_device_4(sc, off, val0);
1444 	vtpci_modern_write_device_4(sc, off + 4, val1);
1445 }
1446