xref: /freebsd/sys/dev/virtio/pci/virtio_pci_legacy.c (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 legacy VirtIO PCI interface. */
30 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/bus.h>
34 #include <sys/lock.h>
35 #include <sys/kernel.h>
36 #include <sys/module.h>
37 #include <sys/endian.h>
38 
39 #include <machine/bus.h>
40 #include <machine/resource.h>
41 #include <sys/bus.h>
42 #include <sys/rman.h>
43 
44 #include <dev/pci/pcivar.h>
45 #include <dev/pci/pcireg.h>
46 
47 #include <dev/virtio/virtio.h>
48 #include <dev/virtio/virtqueue.h>
49 #include <dev/virtio/pci/virtio_pci.h>
50 #include <dev/virtio/pci/virtio_pci_legacy_var.h>
51 
52 #include "virtio_bus_if.h"
53 #include "virtio_pci_if.h"
54 #include "virtio_if.h"
55 
56 struct vtpci_legacy_softc {
57 	device_t			 vtpci_dev;
58 	struct vtpci_common		 vtpci_common;
59 	int				 vtpci_res_type;
60 	struct resource			*vtpci_res;
61 	struct resource			*vtpci_msix_table_res;
62 	struct resource			*vtpci_msix_pba_res;
63 };
64 
65 static int	vtpci_legacy_probe(device_t);
66 static int	vtpci_legacy_attach(device_t);
67 static int	vtpci_legacy_detach(device_t);
68 static int	vtpci_legacy_suspend(device_t);
69 static int	vtpci_legacy_resume(device_t);
70 static int	vtpci_legacy_shutdown(device_t);
71 
72 static void	vtpci_legacy_driver_added(device_t, driver_t *);
73 static void	vtpci_legacy_child_detached(device_t, device_t);
74 static int	vtpci_legacy_read_ivar(device_t, device_t, int, uintptr_t *);
75 static int	vtpci_legacy_write_ivar(device_t, device_t, int, uintptr_t);
76 
77 static uint8_t	vtpci_legacy_read_isr(device_t);
78 static uint16_t	vtpci_legacy_get_vq_size(device_t, int);
79 static bus_size_t vtpci_legacy_get_vq_notify_off(device_t, int);
80 static void	vtpci_legacy_set_vq(device_t, struct virtqueue *);
81 static void	vtpci_legacy_disable_vq(device_t, int);
82 static int	vtpci_legacy_register_cfg_msix(device_t,
83 		    struct vtpci_interrupt *);
84 static int	vtpci_legacy_register_vq_msix(device_t, int idx,
85 		    struct vtpci_interrupt *);
86 
87 static uint64_t	vtpci_legacy_negotiate_features(device_t, uint64_t);
88 static bool	vtpci_legacy_with_feature(device_t, uint64_t);
89 static int	vtpci_legacy_alloc_virtqueues(device_t, int,
90 		    struct vq_alloc_info *);
91 static int	vtpci_legacy_setup_interrupts(device_t, enum intr_type);
92 static void	vtpci_legacy_stop(device_t);
93 static int	vtpci_legacy_reinit(device_t, uint64_t);
94 static void	vtpci_legacy_reinit_complete(device_t);
95 static void	vtpci_legacy_notify_vq(device_t, uint16_t, bus_size_t);
96 static void	vtpci_legacy_read_dev_config(device_t, bus_size_t, void *, int);
97 static void	vtpci_legacy_write_dev_config(device_t, bus_size_t, const void *, int);
98 
99 static bool	vtpci_legacy_setup_msix(struct vtpci_legacy_softc *sc);
100 static void	vtpci_legacy_teardown_msix(struct vtpci_legacy_softc *sc);
101 static int	vtpci_legacy_alloc_resources(struct vtpci_legacy_softc *);
102 static void	vtpci_legacy_free_resources(struct vtpci_legacy_softc *);
103 
104 static void	vtpci_legacy_probe_and_attach_child(struct vtpci_legacy_softc *);
105 
106 static uint8_t	vtpci_legacy_get_status(struct vtpci_legacy_softc *);
107 static void	vtpci_legacy_set_status(struct vtpci_legacy_softc *, uint8_t);
108 static void	vtpci_legacy_select_virtqueue(struct vtpci_legacy_softc *, int);
109 static void	vtpci_legacy_reset(struct vtpci_legacy_softc *);
110 
111 #define VIRTIO_PCI_LEGACY_CONFIG(_sc) \
112     VIRTIO_PCI_CONFIG_OFF(vtpci_is_msix_enabled(&(_sc)->vtpci_common))
113 
114 #define vtpci_legacy_read_config_1(sc, o) \
115     bus_read_1((sc)->vtpci_res, (o))
116 #define vtpci_legacy_write_config_1(sc, o, v) \
117     bus_write_1((sc)->vtpci_res, (o), (v))
118 /*
119  * VirtIO specifies that PCI Configuration area is guest endian. However,
120  * since PCI devices are inherently little-endian, on big-endian systems
121  * the bus layer transparently converts it to BE. For virtio-legacy, this
122  * conversion is undesired, so an extra byte swap is required to fix it.
123  */
124 #define vtpci_legacy_read_config_2(sc, o) \
125     le16toh(bus_read_2((sc)->vtpci_res, (o)))
126 #define vtpci_legacy_read_config_4(sc, o) \
127     le32toh(bus_read_4((sc)->vtpci_res, (o)))
128 #define vtpci_legacy_write_config_2(sc, o, v) \
129     bus_write_2((sc)->vtpci_res, (o), (htole16(v)))
130 #define vtpci_legacy_write_config_4(sc, o, v) \
131     bus_write_4((sc)->vtpci_res, (o), (htole32(v)))
132 /* PCI Header LE. On BE systems the bus layer takes care of byte swapping. */
133 #define vtpci_legacy_read_header_2(sc, o) \
134     bus_read_2((sc)->vtpci_res, (o))
135 #define vtpci_legacy_read_header_4(sc, o) \
136     bus_read_4((sc)->vtpci_res, (o))
137 #define vtpci_legacy_write_header_2(sc, o, v) \
138     bus_write_2((sc)->vtpci_res, (o), (v))
139 #define vtpci_legacy_write_header_4(sc, o, v) \
140     bus_write_4((sc)->vtpci_res, (o), (v))
141 
142 static device_method_t vtpci_legacy_methods[] = {
143 	/* Device interface. */
144 	DEVMETHOD(device_probe,			  vtpci_legacy_probe),
145 	DEVMETHOD(device_attach,		  vtpci_legacy_attach),
146 	DEVMETHOD(device_detach,		  vtpci_legacy_detach),
147 	DEVMETHOD(device_suspend,		  vtpci_legacy_suspend),
148 	DEVMETHOD(device_resume,		  vtpci_legacy_resume),
149 	DEVMETHOD(device_shutdown,		  vtpci_legacy_shutdown),
150 
151 	/* Bus interface. */
152 	DEVMETHOD(bus_driver_added,		  vtpci_legacy_driver_added),
153 	DEVMETHOD(bus_child_detached,		  vtpci_legacy_child_detached),
154 	DEVMETHOD(bus_child_pnpinfo,		  virtio_child_pnpinfo),
155 	DEVMETHOD(bus_read_ivar,		  vtpci_legacy_read_ivar),
156 	DEVMETHOD(bus_write_ivar,		  vtpci_legacy_write_ivar),
157 
158 	/* VirtIO PCI interface. */
159 	DEVMETHOD(virtio_pci_read_isr,		 vtpci_legacy_read_isr),
160 	DEVMETHOD(virtio_pci_get_vq_size,	 vtpci_legacy_get_vq_size),
161 	DEVMETHOD(virtio_pci_get_vq_notify_off,	 vtpci_legacy_get_vq_notify_off),
162 	DEVMETHOD(virtio_pci_set_vq,		 vtpci_legacy_set_vq),
163 	DEVMETHOD(virtio_pci_disable_vq,	 vtpci_legacy_disable_vq),
164 	DEVMETHOD(virtio_pci_register_cfg_msix,  vtpci_legacy_register_cfg_msix),
165 	DEVMETHOD(virtio_pci_register_vq_msix,	 vtpci_legacy_register_vq_msix),
166 
167 	/* VirtIO bus interface. */
168 	DEVMETHOD(virtio_bus_negotiate_features,  vtpci_legacy_negotiate_features),
169 	DEVMETHOD(virtio_bus_with_feature,	  vtpci_legacy_with_feature),
170 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtpci_legacy_alloc_virtqueues),
171 	DEVMETHOD(virtio_bus_setup_intr,	  vtpci_legacy_setup_interrupts),
172 	DEVMETHOD(virtio_bus_stop,		  vtpci_legacy_stop),
173 	DEVMETHOD(virtio_bus_reinit,		  vtpci_legacy_reinit),
174 	DEVMETHOD(virtio_bus_reinit_complete,	  vtpci_legacy_reinit_complete),
175 	DEVMETHOD(virtio_bus_notify_vq,		  vtpci_legacy_notify_vq),
176 	DEVMETHOD(virtio_bus_read_device_config,  vtpci_legacy_read_dev_config),
177 	DEVMETHOD(virtio_bus_write_device_config, vtpci_legacy_write_dev_config),
178 
179 	DEVMETHOD_END
180 };
181 
182 static driver_t vtpci_legacy_driver = {
183 	.name = "virtio_pci",
184 	.methods = vtpci_legacy_methods,
185 	.size = sizeof(struct vtpci_legacy_softc)
186 };
187 
188 DRIVER_MODULE(virtio_pci_legacy, pci, vtpci_legacy_driver, 0, 0);
189 
190 static int
191 vtpci_legacy_probe(device_t dev)
192 {
193 	char desc[64];
194 	const char *name;
195 
196 	if (pci_get_vendor(dev) != VIRTIO_PCI_VENDORID)
197 		return (ENXIO);
198 
199 	if (pci_get_device(dev) < VIRTIO_PCI_DEVICEID_MIN ||
200 	    pci_get_device(dev) > VIRTIO_PCI_DEVICEID_LEGACY_MAX)
201 		return (ENXIO);
202 
203 	if (pci_get_revid(dev) != VIRTIO_PCI_ABI_VERSION)
204 		return (ENXIO);
205 
206 	name = virtio_device_name(pci_get_subdevice(dev));
207 	if (name == NULL)
208 		name = "Unknown";
209 
210 	snprintf(desc, sizeof(desc), "VirtIO PCI (legacy) %s adapter", name);
211 	device_set_desc_copy(dev, desc);
212 
213 	/* Prefer transitional modern VirtIO PCI. */
214 	return (BUS_PROBE_LOW_PRIORITY);
215 }
216 
217 static int
218 vtpci_legacy_attach(device_t dev)
219 {
220 	struct vtpci_legacy_softc *sc;
221 	int error;
222 
223 	sc = device_get_softc(dev);
224 	sc->vtpci_dev = dev;
225 	vtpci_init(&sc->vtpci_common, dev, false);
226 
227 	error = vtpci_legacy_alloc_resources(sc);
228 	if (error) {
229 		device_printf(dev, "cannot map I/O space nor memory space\n");
230 		return (error);
231 	}
232 
233 	if (vtpci_is_msix_available(&sc->vtpci_common) &&
234 	    !vtpci_legacy_setup_msix(sc)) {
235 		device_printf(dev, "cannot setup MSI-x resources\n");
236 		error = ENXIO;
237 		goto fail;
238 	}
239 
240 	vtpci_legacy_reset(sc);
241 
242 	/* Tell the host we've noticed this device. */
243 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
244 
245 	error = vtpci_add_child(&sc->vtpci_common);
246 	if (error)
247 		goto fail;
248 
249 	vtpci_legacy_probe_and_attach_child(sc);
250 
251 	return (0);
252 
253 fail:
254 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_FAILED);
255 	vtpci_legacy_detach(dev);
256 
257 	return (error);
258 }
259 
260 static int
261 vtpci_legacy_detach(device_t dev)
262 {
263 	struct vtpci_legacy_softc *sc;
264 	int error;
265 
266 	sc = device_get_softc(dev);
267 
268 	error = vtpci_delete_child(&sc->vtpci_common);
269 	if (error)
270 		return (error);
271 
272 	vtpci_legacy_reset(sc);
273 	vtpci_legacy_teardown_msix(sc);
274 	vtpci_legacy_free_resources(sc);
275 
276 	return (0);
277 }
278 
279 static int
280 vtpci_legacy_suspend(device_t dev)
281 {
282 	return (bus_generic_suspend(dev));
283 }
284 
285 static int
286 vtpci_legacy_resume(device_t dev)
287 {
288 	return (bus_generic_resume(dev));
289 }
290 
291 static int
292 vtpci_legacy_shutdown(device_t dev)
293 {
294 	(void) bus_generic_shutdown(dev);
295 	/* Forcibly stop the host device. */
296 	vtpci_legacy_stop(dev);
297 
298 	return (0);
299 }
300 
301 static void
302 vtpci_legacy_driver_added(device_t dev, driver_t *driver)
303 {
304 	vtpci_legacy_probe_and_attach_child(device_get_softc(dev));
305 }
306 
307 static void
308 vtpci_legacy_child_detached(device_t dev, device_t child)
309 {
310 	struct vtpci_legacy_softc *sc;
311 
312 	sc = device_get_softc(dev);
313 
314 	vtpci_legacy_reset(sc);
315 	vtpci_child_detached(&sc->vtpci_common);
316 
317 	/* After the reset, retell the host we've noticed this device. */
318 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
319 }
320 
321 static int
322 vtpci_legacy_read_ivar(device_t dev, device_t child, int index,
323     uintptr_t *result)
324 {
325 	struct vtpci_legacy_softc *sc;
326 	struct vtpci_common *cn;
327 
328 	sc = device_get_softc(dev);
329 	cn = &sc->vtpci_common;
330 
331 	if (vtpci_child_device(cn) != child)
332 		return (ENOENT);
333 
334 	switch (index) {
335 	case VIRTIO_IVAR_DEVTYPE:
336 		*result = pci_get_subdevice(dev);
337 		break;
338 	default:
339 		return (vtpci_read_ivar(cn, index, result));
340 	}
341 
342 	return (0);
343 }
344 
345 static int
346 vtpci_legacy_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
347 {
348 	struct vtpci_legacy_softc *sc;
349 	struct vtpci_common *cn;
350 
351 	sc = device_get_softc(dev);
352 	cn = &sc->vtpci_common;
353 
354 	if (vtpci_child_device(cn) != child)
355 		return (ENOENT);
356 
357 	switch (index) {
358 	default:
359 		return (vtpci_write_ivar(cn, index, value));
360 	}
361 
362 	return (0);
363 }
364 
365 static uint64_t
366 vtpci_legacy_negotiate_features(device_t dev, uint64_t child_features)
367 {
368 	struct vtpci_legacy_softc *sc;
369 	uint64_t host_features, features;
370 
371 	sc = device_get_softc(dev);
372 	host_features = vtpci_legacy_read_header_4(sc, VIRTIO_PCI_HOST_FEATURES);
373 
374 	features = vtpci_negotiate_features(&sc->vtpci_common,
375 	    child_features, host_features);
376 	vtpci_legacy_write_header_4(sc, VIRTIO_PCI_GUEST_FEATURES, features);
377 
378 	return (features);
379 }
380 
381 static bool
382 vtpci_legacy_with_feature(device_t dev, uint64_t feature)
383 {
384 	struct vtpci_legacy_softc *sc;
385 
386 	sc = device_get_softc(dev);
387 
388 	return (vtpci_with_feature(&sc->vtpci_common, feature));
389 }
390 
391 static int
392 vtpci_legacy_alloc_virtqueues(device_t dev, int nvqs,
393     struct vq_alloc_info *vq_info)
394 {
395 	struct vtpci_legacy_softc *sc;
396 	struct vtpci_common *cn;
397 
398 	sc = device_get_softc(dev);
399 	cn = &sc->vtpci_common;
400 
401 	return (vtpci_alloc_virtqueues(cn, nvqs, vq_info));
402 }
403 
404 static int
405 vtpci_legacy_setup_interrupts(device_t dev, enum intr_type type)
406 {
407 	struct vtpci_legacy_softc *sc;
408 
409 	sc = device_get_softc(dev);
410 
411 	return (vtpci_setup_interrupts(&sc->vtpci_common, type));
412 }
413 
414 static void
415 vtpci_legacy_stop(device_t dev)
416 {
417 	vtpci_legacy_reset(device_get_softc(dev));
418 }
419 
420 static int
421 vtpci_legacy_reinit(device_t dev, uint64_t features)
422 {
423 	struct vtpci_legacy_softc *sc;
424 	struct vtpci_common *cn;
425 	int error;
426 
427 	sc = device_get_softc(dev);
428 	cn = &sc->vtpci_common;
429 
430 	/*
431 	 * Redrive the device initialization. This is a bit of an abuse of
432 	 * the specification, but VirtualBox, QEMU/KVM, and BHyVe seem to
433 	 * play nice.
434 	 *
435 	 * We do not allow the host device to change from what was originally
436 	 * negotiated beyond what the guest driver changed. MSIX state should
437 	 * not change, number of virtqueues and their size remain the same, etc.
438 	 * This will need to be rethought when we want to support migration.
439 	 */
440 
441 	if (vtpci_legacy_get_status(sc) != VIRTIO_CONFIG_STATUS_RESET)
442 		vtpci_legacy_stop(dev);
443 
444 	/*
445 	 * Quickly drive the status through ACK and DRIVER. The device does
446 	 * not become usable again until DRIVER_OK in reinit complete.
447 	 */
448 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_ACK);
449 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER);
450 
451 	vtpci_legacy_negotiate_features(dev, features);
452 
453 	error = vtpci_reinit(cn);
454 	if (error)
455 		return (error);
456 
457 	return (0);
458 }
459 
460 static void
461 vtpci_legacy_reinit_complete(device_t dev)
462 {
463 	struct vtpci_legacy_softc *sc;
464 
465 	sc = device_get_softc(dev);
466 
467 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER_OK);
468 }
469 
470 static void
471 vtpci_legacy_notify_vq(device_t dev, uint16_t queue, bus_size_t offset)
472 {
473 	struct vtpci_legacy_softc *sc;
474 
475 	sc = device_get_softc(dev);
476 	MPASS(offset == VIRTIO_PCI_QUEUE_NOTIFY);
477 
478 	vtpci_legacy_write_header_2(sc, offset, queue);
479 }
480 
481 static uint8_t
482 vtpci_legacy_get_status(struct vtpci_legacy_softc *sc)
483 {
484 	return (vtpci_legacy_read_config_1(sc, VIRTIO_PCI_STATUS));
485 }
486 
487 static void
488 vtpci_legacy_set_status(struct vtpci_legacy_softc *sc, uint8_t status)
489 {
490 	if (status != VIRTIO_CONFIG_STATUS_RESET)
491 		status |= vtpci_legacy_get_status(sc);
492 
493 	vtpci_legacy_write_config_1(sc, VIRTIO_PCI_STATUS, status);
494 }
495 
496 static void
497 vtpci_legacy_read_dev_config(device_t dev, bus_size_t offset,
498     void *dst, int length)
499 {
500 	struct vtpci_legacy_softc *sc;
501 	bus_size_t off;
502 	uint8_t *d;
503 	int i;
504 
505 	sc = device_get_softc(dev);
506 	off = VIRTIO_PCI_LEGACY_CONFIG(sc) + offset;
507 
508 	d = dst;
509 	for (i = 0; i < length; i++) {
510 		d[i] = vtpci_legacy_read_config_1(sc, off + i);
511 	}
512 }
513 
514 static void
515 vtpci_legacy_write_dev_config(device_t dev, bus_size_t offset,
516     const void *src, int length)
517 {
518 	struct vtpci_legacy_softc *sc;
519 	bus_size_t off;
520 	const uint8_t *s;
521 	int i;
522 
523 	sc = device_get_softc(dev);
524 	off = VIRTIO_PCI_LEGACY_CONFIG(sc) + offset;
525 
526 	s = src;
527 	for (i = 0; i < length; i++) {
528 		vtpci_legacy_write_config_1(sc, off + i, s[i]);
529 	}
530 }
531 
532 static bool
533 vtpci_legacy_setup_msix(struct vtpci_legacy_softc *sc)
534 {
535 	device_t dev;
536 	int rid, table_rid;
537 
538 	dev = sc->vtpci_dev;
539 
540 	rid = table_rid = pci_msix_table_bar(dev);
541 	if (rid != PCIR_BAR(0)) {
542 		sc->vtpci_msix_table_res = bus_alloc_resource_any(
543 		    dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
544 		if (sc->vtpci_msix_table_res == NULL)
545 			return (false);
546 	}
547 
548 	rid = pci_msix_pba_bar(dev);
549 	if (rid != table_rid && rid != PCIR_BAR(0)) {
550 		sc->vtpci_msix_pba_res = bus_alloc_resource_any(
551 		    dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
552 		if (sc->vtpci_msix_pba_res == NULL)
553 			return (false);
554 	}
555 
556 	return (true);
557 }
558 
559 static void
560 vtpci_legacy_teardown_msix(struct vtpci_legacy_softc *sc)
561 {
562 	device_t dev;
563 
564 	dev = sc->vtpci_dev;
565 
566 	if (sc->vtpci_msix_pba_res != NULL) {
567 		bus_release_resource(dev, SYS_RES_MEMORY,
568 		    rman_get_rid(sc->vtpci_msix_pba_res),
569 		    sc->vtpci_msix_pba_res);
570 		sc->vtpci_msix_pba_res = NULL;
571 	}
572 	if (sc->vtpci_msix_table_res != NULL) {
573 		bus_release_resource(dev, SYS_RES_MEMORY,
574 		    rman_get_rid(sc->vtpci_msix_table_res),
575 		    sc->vtpci_msix_table_res);
576 		sc->vtpci_msix_table_res = NULL;
577 	}
578 }
579 
580 static int
581 vtpci_legacy_alloc_resources(struct vtpci_legacy_softc *sc)
582 {
583 	const int res_types[] = { SYS_RES_IOPORT, SYS_RES_MEMORY };
584 	device_t dev;
585 	int rid, i;
586 
587 	dev = sc->vtpci_dev;
588 
589 	/*
590 	 * Most hypervisors export the common configuration structure in IO
591 	 * space, but some use memory space; try both.
592 	 */
593 	for (i = 0; nitems(res_types); i++) {
594 		rid = PCIR_BAR(0);
595 		sc->vtpci_res_type = res_types[i];
596 		sc->vtpci_res = bus_alloc_resource_any(dev, res_types[i], &rid,
597 		    RF_ACTIVE);
598 		if (sc->vtpci_res != NULL)
599 			break;
600 	}
601 	if (sc->vtpci_res == NULL)
602 		return (ENXIO);
603 
604 	return (0);
605 }
606 
607 static void
608 vtpci_legacy_free_resources(struct vtpci_legacy_softc *sc)
609 {
610 	device_t dev;
611 
612 	dev = sc->vtpci_dev;
613 
614 	if (sc->vtpci_res != NULL) {
615 		bus_release_resource(dev, sc->vtpci_res_type, PCIR_BAR(0),
616 		    sc->vtpci_res);
617 		sc->vtpci_res = NULL;
618 	}
619 }
620 
621 static void
622 vtpci_legacy_probe_and_attach_child(struct vtpci_legacy_softc *sc)
623 {
624 	device_t dev, child;
625 
626 	dev = sc->vtpci_dev;
627 	child = vtpci_child_device(&sc->vtpci_common);
628 
629 	if (child == NULL || device_get_state(child) != DS_NOTPRESENT)
630 		return;
631 
632 	if (device_probe(child) != 0)
633 		return;
634 
635 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER);
636 
637 	if (device_attach(child) != 0) {
638 		vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_FAILED);
639 		/* Reset status for future attempt. */
640 		vtpci_legacy_child_detached(dev, child);
641 	} else {
642 		vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_DRIVER_OK);
643 		VIRTIO_ATTACH_COMPLETED(child);
644 	}
645 }
646 
647 static int
648 vtpci_legacy_register_msix(struct vtpci_legacy_softc *sc, int offset,
649     struct vtpci_interrupt *intr)
650 {
651 	uint16_t vector;
652 
653 	if (intr != NULL) {
654 		/* Map from guest rid to host vector. */
655 		vector = intr->vti_rid - 1;
656 	} else
657 		vector = VIRTIO_MSI_NO_VECTOR;
658 
659 	vtpci_legacy_write_header_2(sc, offset, vector);
660 	return (vtpci_legacy_read_header_2(sc, offset) == vector ? 0 : ENODEV);
661 }
662 
663 static int
664 vtpci_legacy_register_cfg_msix(device_t dev, struct vtpci_interrupt *intr)
665 {
666 	struct vtpci_legacy_softc *sc;
667 	int error;
668 
669 	sc = device_get_softc(dev);
670 
671 	error = vtpci_legacy_register_msix(sc, VIRTIO_MSI_CONFIG_VECTOR, intr);
672 	if (error) {
673 		device_printf(dev,
674 		    "unable to register config MSIX interrupt\n");
675 		return (error);
676 	}
677 
678 	return (0);
679 }
680 
681 static int
682 vtpci_legacy_register_vq_msix(device_t dev, int idx,
683     struct vtpci_interrupt *intr)
684 {
685 	struct vtpci_legacy_softc *sc;
686 	int error;
687 
688 	sc = device_get_softc(dev);
689 
690 	vtpci_legacy_select_virtqueue(sc, idx);
691 	error = vtpci_legacy_register_msix(sc, VIRTIO_MSI_QUEUE_VECTOR, intr);
692 	if (error) {
693 		device_printf(dev,
694 		    "unable to register virtqueue MSIX interrupt\n");
695 		return (error);
696 	}
697 
698 	return (0);
699 }
700 
701 static void
702 vtpci_legacy_reset(struct vtpci_legacy_softc *sc)
703 {
704 	/*
705 	 * Setting the status to RESET sets the host device to the
706 	 * original, uninitialized state.
707 	 */
708 	vtpci_legacy_set_status(sc, VIRTIO_CONFIG_STATUS_RESET);
709 	(void) vtpci_legacy_get_status(sc);
710 }
711 
712 static void
713 vtpci_legacy_select_virtqueue(struct vtpci_legacy_softc *sc, int idx)
714 {
715 	vtpci_legacy_write_header_2(sc, VIRTIO_PCI_QUEUE_SEL, idx);
716 }
717 
718 static uint8_t
719 vtpci_legacy_read_isr(device_t dev)
720 {
721 	struct vtpci_legacy_softc *sc;
722 
723 	sc = device_get_softc(dev);
724 
725 	return (vtpci_legacy_read_config_1(sc, VIRTIO_PCI_ISR));
726 }
727 
728 static uint16_t
729 vtpci_legacy_get_vq_size(device_t dev, int idx)
730 {
731 	struct vtpci_legacy_softc *sc;
732 
733 	sc = device_get_softc(dev);
734 
735 	vtpci_legacy_select_virtqueue(sc, idx);
736 	return (vtpci_legacy_read_header_2(sc, VIRTIO_PCI_QUEUE_NUM));
737 }
738 
739 static bus_size_t
740 vtpci_legacy_get_vq_notify_off(device_t dev, int idx)
741 {
742 	return (VIRTIO_PCI_QUEUE_NOTIFY);
743 }
744 
745 static void
746 vtpci_legacy_set_vq(device_t dev, struct virtqueue *vq)
747 {
748 	struct vtpci_legacy_softc *sc;
749 
750 	sc = device_get_softc(dev);
751 
752 	vtpci_legacy_select_virtqueue(sc, virtqueue_index(vq));
753 	vtpci_legacy_write_header_4(sc, VIRTIO_PCI_QUEUE_PFN,
754 	    virtqueue_paddr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT);
755 }
756 
757 static void
758 vtpci_legacy_disable_vq(device_t dev, int idx)
759 {
760 	struct vtpci_legacy_softc *sc;
761 
762 	sc = device_get_softc(dev);
763 
764 	vtpci_legacy_select_virtqueue(sc, idx);
765 	vtpci_legacy_write_header_4(sc, VIRTIO_PCI_QUEUE_PFN, 0);
766 }
767