xref: /freebsd/sys/dev/virtio/mmio/virtio_mmio.c (revision 5def4c47d4bd90b209b9b4a4ba9faec15846d8fd)
1 /*-
2  * Copyright (c) 2014 Ruslan Bukin <br@bsdpad.com>
3  * Copyright (c) 2014 The FreeBSD Foundation
4  * All rights reserved.
5  *
6  * This software was developed by SRI International and the University of
7  * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
8  * ("CTSRD"), as part of the DARPA CRASH research programme.
9  *
10  * Portions of this software were developed by Andrew Turner
11  * under sponsorship from the FreeBSD Foundation.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 /*
36  * VirtIO MMIO interface.
37  * This driver is heavily based on VirtIO PCI interface driver.
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/bus.h>
46 #include <sys/kernel.h>
47 #include <sys/module.h>
48 #include <sys/malloc.h>
49 #include <sys/rman.h>
50 #include <sys/endian.h>
51 
52 #include <machine/bus.h>
53 #include <machine/resource.h>
54 
55 #include <dev/virtio/virtio.h>
56 #include <dev/virtio/virtqueue.h>
57 #include <dev/virtio/mmio/virtio_mmio.h>
58 
59 #include "virtio_mmio_if.h"
60 #include "virtio_bus_if.h"
61 #include "virtio_if.h"
62 
63 struct vtmmio_virtqueue {
64 	struct virtqueue	*vtv_vq;
65 	int			 vtv_no_intr;
66 };
67 
68 static int	vtmmio_detach(device_t);
69 static int	vtmmio_suspend(device_t);
70 static int	vtmmio_resume(device_t);
71 static int	vtmmio_shutdown(device_t);
72 static void	vtmmio_driver_added(device_t, driver_t *);
73 static void	vtmmio_child_detached(device_t, device_t);
74 static int	vtmmio_read_ivar(device_t, device_t, int, uintptr_t *);
75 static int	vtmmio_write_ivar(device_t, device_t, int, uintptr_t);
76 static uint64_t	vtmmio_negotiate_features(device_t, uint64_t);
77 static int	vtmmio_with_feature(device_t, uint64_t);
78 static void	vtmmio_set_virtqueue(struct vtmmio_softc *sc,
79 		    struct virtqueue *vq, uint32_t size);
80 static int	vtmmio_alloc_virtqueues(device_t, int, int,
81 		    struct vq_alloc_info *);
82 static int	vtmmio_setup_intr(device_t, enum intr_type);
83 static void	vtmmio_stop(device_t);
84 static void	vtmmio_poll(device_t);
85 static int	vtmmio_reinit(device_t, uint64_t);
86 static void	vtmmio_reinit_complete(device_t);
87 static void	vtmmio_notify_virtqueue(device_t, uint16_t, bus_size_t);
88 static uint8_t	vtmmio_get_status(device_t);
89 static void	vtmmio_set_status(device_t, uint8_t);
90 static void	vtmmio_read_dev_config(device_t, bus_size_t, void *, int);
91 static void	vtmmio_write_dev_config(device_t, bus_size_t, void *, int);
92 static void	vtmmio_describe_features(struct vtmmio_softc *, const char *,
93 		    uint64_t);
94 static void	vtmmio_probe_and_attach_child(struct vtmmio_softc *);
95 static int	vtmmio_reinit_virtqueue(struct vtmmio_softc *, int);
96 static void	vtmmio_free_interrupts(struct vtmmio_softc *);
97 static void	vtmmio_free_virtqueues(struct vtmmio_softc *);
98 static void	vtmmio_release_child_resources(struct vtmmio_softc *);
99 static void	vtmmio_reset(struct vtmmio_softc *);
100 static void	vtmmio_select_virtqueue(struct vtmmio_softc *, int);
101 static void	vtmmio_vq_intr(void *);
102 
103 /*
104  * I/O port read/write wrappers.
105  */
106 #define vtmmio_write_config_1(sc, o, v)				\
107 do {								\
108 	if (sc->platform != NULL)				\
109 		VIRTIO_MMIO_PREWRITE(sc->platform, (o), (v));	\
110 	bus_write_1((sc)->res[0], (o), (v)); 			\
111 	if (sc->platform != NULL)				\
112 		VIRTIO_MMIO_NOTE(sc->platform, (o), (v));	\
113 } while (0)
114 #define vtmmio_write_config_2(sc, o, v)				\
115 do {								\
116 	if (sc->platform != NULL)				\
117 		VIRTIO_MMIO_PREWRITE(sc->platform, (o), (v));	\
118 	bus_write_2((sc)->res[0], (o), (v));			\
119 	if (sc->platform != NULL)				\
120 		VIRTIO_MMIO_NOTE(sc->platform, (o), (v));	\
121 } while (0)
122 #define vtmmio_write_config_4(sc, o, v)				\
123 do {								\
124 	if (sc->platform != NULL)				\
125 		VIRTIO_MMIO_PREWRITE(sc->platform, (o), (v));	\
126 	bus_write_4((sc)->res[0], (o), (v));			\
127 	if (sc->platform != NULL)				\
128 		VIRTIO_MMIO_NOTE(sc->platform, (o), (v));	\
129 } while (0)
130 
131 #define vtmmio_read_config_1(sc, o) \
132 	bus_read_1((sc)->res[0], (o))
133 #define vtmmio_read_config_2(sc, o) \
134 	bus_read_2((sc)->res[0], (o))
135 #define vtmmio_read_config_4(sc, o) \
136 	bus_read_4((sc)->res[0], (o))
137 
138 static device_method_t vtmmio_methods[] = {
139 	/* Device interface. */
140 	DEVMETHOD(device_attach,		  vtmmio_attach),
141 	DEVMETHOD(device_detach,		  vtmmio_detach),
142 	DEVMETHOD(device_suspend,		  vtmmio_suspend),
143 	DEVMETHOD(device_resume,		  vtmmio_resume),
144 	DEVMETHOD(device_shutdown,		  vtmmio_shutdown),
145 
146 	/* Bus interface. */
147 	DEVMETHOD(bus_driver_added,		  vtmmio_driver_added),
148 	DEVMETHOD(bus_child_detached,		  vtmmio_child_detached),
149 	DEVMETHOD(bus_child_pnpinfo,		  virtio_child_pnpinfo),
150 	DEVMETHOD(bus_read_ivar,		  vtmmio_read_ivar),
151 	DEVMETHOD(bus_write_ivar,		  vtmmio_write_ivar),
152 
153 	/* VirtIO bus interface. */
154 	DEVMETHOD(virtio_bus_negotiate_features,  vtmmio_negotiate_features),
155 	DEVMETHOD(virtio_bus_with_feature,	  vtmmio_with_feature),
156 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtmmio_alloc_virtqueues),
157 	DEVMETHOD(virtio_bus_setup_intr,	  vtmmio_setup_intr),
158 	DEVMETHOD(virtio_bus_stop,		  vtmmio_stop),
159 	DEVMETHOD(virtio_bus_poll,		  vtmmio_poll),
160 	DEVMETHOD(virtio_bus_reinit,		  vtmmio_reinit),
161 	DEVMETHOD(virtio_bus_reinit_complete,	  vtmmio_reinit_complete),
162 	DEVMETHOD(virtio_bus_notify_vq,		  vtmmio_notify_virtqueue),
163 	DEVMETHOD(virtio_bus_read_device_config,  vtmmio_read_dev_config),
164 	DEVMETHOD(virtio_bus_write_device_config, vtmmio_write_dev_config),
165 
166 	DEVMETHOD_END
167 };
168 
169 DEFINE_CLASS_0(virtio_mmio, vtmmio_driver, vtmmio_methods,
170     sizeof(struct vtmmio_softc));
171 
172 MODULE_VERSION(virtio_mmio, 1);
173 
174 int
175 vtmmio_probe(device_t dev)
176 {
177 	struct vtmmio_softc *sc;
178 	int rid;
179 	uint32_t magic, version;
180 
181 	sc = device_get_softc(dev);
182 
183 	rid = 0;
184 	sc->res[0] = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
185 	    RF_ACTIVE);
186 	if (sc->res[0] == NULL) {
187 		device_printf(dev, "Cannot allocate memory window.\n");
188 		return (ENXIO);
189 	}
190 
191 	magic = vtmmio_read_config_4(sc, VIRTIO_MMIO_MAGIC_VALUE);
192 	if (magic != VIRTIO_MMIO_MAGIC_VIRT) {
193 		device_printf(dev, "Bad magic value %#x\n", magic);
194 		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
195 		return (ENXIO);
196 	}
197 
198 	version = vtmmio_read_config_4(sc, VIRTIO_MMIO_VERSION);
199 	if (version < 1 || version > 2) {
200 		device_printf(dev, "Unsupported version: %#x\n", version);
201 		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
202 		return (ENXIO);
203 	}
204 
205 	if (vtmmio_read_config_4(sc, VIRTIO_MMIO_DEVICE_ID) == 0) {
206 		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
207 		return (ENXIO);
208 	}
209 
210 	bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
211 
212 	device_set_desc(dev, "VirtIO MMIO adapter");
213 	return (BUS_PROBE_DEFAULT);
214 }
215 
216 static int
217 vtmmio_setup_intr(device_t dev, enum intr_type type)
218 {
219 	struct vtmmio_softc *sc;
220 	int rid;
221 	int err;
222 
223 	sc = device_get_softc(dev);
224 
225 	if (sc->platform != NULL) {
226 		err = VIRTIO_MMIO_SETUP_INTR(sc->platform, sc->dev,
227 					vtmmio_vq_intr, sc);
228 		if (err == 0) {
229 			/* Okay we have backend-specific interrupts */
230 			return (0);
231 		}
232 	}
233 
234 	rid = 0;
235 	sc->res[1] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
236 		RF_ACTIVE);
237 	if (!sc->res[1]) {
238 		device_printf(dev, "Can't allocate interrupt\n");
239 		return (ENXIO);
240 	}
241 
242 	if (bus_setup_intr(dev, sc->res[1], type | INTR_MPSAFE,
243 		NULL, vtmmio_vq_intr, sc, &sc->ih)) {
244 		device_printf(dev, "Can't setup the interrupt\n");
245 		return (ENXIO);
246 	}
247 
248 	return (0);
249 }
250 
251 int
252 vtmmio_attach(device_t dev)
253 {
254 	struct vtmmio_softc *sc;
255 	device_t child;
256 	int rid;
257 
258 	sc = device_get_softc(dev);
259 	sc->dev = dev;
260 
261 	rid = 0;
262 	sc->res[0] = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
263 			RF_ACTIVE);
264 	if (sc->res[0] == NULL) {
265 		device_printf(dev, "Cannot allocate memory window.\n");
266 		return (ENXIO);
267 	}
268 
269 	sc->vtmmio_version = vtmmio_read_config_4(sc, VIRTIO_MMIO_VERSION);
270 
271 	vtmmio_reset(sc);
272 
273 	/* Tell the host we've noticed this device. */
274 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
275 
276 	if ((child = device_add_child(dev, NULL, -1)) == NULL) {
277 		device_printf(dev, "Cannot create child device.\n");
278 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_FAILED);
279 		vtmmio_detach(dev);
280 		return (ENOMEM);
281 	}
282 
283 	sc->vtmmio_child_dev = child;
284 	vtmmio_probe_and_attach_child(sc);
285 
286 	return (0);
287 }
288 
289 static int
290 vtmmio_detach(device_t dev)
291 {
292 	struct vtmmio_softc *sc;
293 	device_t child;
294 	int error;
295 
296 	sc = device_get_softc(dev);
297 
298 	if ((child = sc->vtmmio_child_dev) != NULL) {
299 		error = device_delete_child(dev, child);
300 		if (error)
301 			return (error);
302 		sc->vtmmio_child_dev = NULL;
303 	}
304 
305 	vtmmio_reset(sc);
306 
307 	if (sc->res[0] != NULL) {
308 		bus_release_resource(dev, SYS_RES_MEMORY, 0,
309 		    sc->res[0]);
310 		sc->res[0] = NULL;
311 	}
312 
313 	return (0);
314 }
315 
316 static int
317 vtmmio_suspend(device_t dev)
318 {
319 
320 	return (bus_generic_suspend(dev));
321 }
322 
323 static int
324 vtmmio_resume(device_t dev)
325 {
326 
327 	return (bus_generic_resume(dev));
328 }
329 
330 static int
331 vtmmio_shutdown(device_t dev)
332 {
333 
334 	(void) bus_generic_shutdown(dev);
335 
336 	/* Forcibly stop the host device. */
337 	vtmmio_stop(dev);
338 
339 	return (0);
340 }
341 
342 static void
343 vtmmio_driver_added(device_t dev, driver_t *driver)
344 {
345 	struct vtmmio_softc *sc;
346 
347 	sc = device_get_softc(dev);
348 
349 	vtmmio_probe_and_attach_child(sc);
350 }
351 
352 static void
353 vtmmio_child_detached(device_t dev, device_t child)
354 {
355 	struct vtmmio_softc *sc;
356 
357 	sc = device_get_softc(dev);
358 
359 	vtmmio_reset(sc);
360 	vtmmio_release_child_resources(sc);
361 }
362 
363 static int
364 vtmmio_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
365 {
366 	struct vtmmio_softc *sc;
367 
368 	sc = device_get_softc(dev);
369 
370 	if (sc->vtmmio_child_dev != child)
371 		return (ENOENT);
372 
373 	switch (index) {
374 	case VIRTIO_IVAR_DEVTYPE:
375 	case VIRTIO_IVAR_SUBDEVICE:
376 		*result = vtmmio_read_config_4(sc, VIRTIO_MMIO_DEVICE_ID);
377 		break;
378 	case VIRTIO_IVAR_VENDOR:
379 		*result = vtmmio_read_config_4(sc, VIRTIO_MMIO_VENDOR_ID);
380 		break;
381 	case VIRTIO_IVAR_SUBVENDOR:
382 	case VIRTIO_IVAR_DEVICE:
383 		/*
384 		 * Dummy value for fields not present in this bus.  Used by
385 		 * bus-agnostic virtio_child_pnpinfo.
386 		 */
387 		*result = 0;
388 		break;
389 	case VIRTIO_IVAR_MODERN:
390 		/*
391 		 * There are several modern (aka MMIO v2) spec compliance
392 		 * issues with this driver, but keep the status quo.
393 		 */
394 		*result = sc->vtmmio_version > 1;
395 		break;
396 	default:
397 		return (ENOENT);
398 	}
399 
400 	return (0);
401 }
402 
403 static int
404 vtmmio_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
405 {
406 	struct vtmmio_softc *sc;
407 
408 	sc = device_get_softc(dev);
409 
410 	if (sc->vtmmio_child_dev != child)
411 		return (ENOENT);
412 
413 	switch (index) {
414 	case VIRTIO_IVAR_FEATURE_DESC:
415 		sc->vtmmio_child_feat_desc = (void *) value;
416 		break;
417 	default:
418 		return (ENOENT);
419 	}
420 
421 	return (0);
422 }
423 
424 static uint64_t
425 vtmmio_negotiate_features(device_t dev, uint64_t child_features)
426 {
427 	struct vtmmio_softc *sc;
428 	uint64_t host_features, features;
429 
430 	sc = device_get_softc(dev);
431 
432 	if (sc->vtmmio_version > 1) {
433 		child_features |= VIRTIO_F_VERSION_1;
434 	}
435 
436 	vtmmio_write_config_4(sc, VIRTIO_MMIO_HOST_FEATURES_SEL, 1);
437 	host_features = vtmmio_read_config_4(sc, VIRTIO_MMIO_HOST_FEATURES);
438 	host_features <<= 32;
439 
440 	vtmmio_write_config_4(sc, VIRTIO_MMIO_HOST_FEATURES_SEL, 0);
441 	host_features |= vtmmio_read_config_4(sc, VIRTIO_MMIO_HOST_FEATURES);
442 
443 	vtmmio_describe_features(sc, "host", host_features);
444 
445 	/*
446 	 * Limit negotiated features to what the driver, virtqueue, and
447 	 * host all support.
448 	 */
449 	features = host_features & child_features;
450 	features = virtio_filter_transport_features(features);
451 	sc->vtmmio_features = features;
452 
453 	vtmmio_describe_features(sc, "negotiated", features);
454 
455 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES_SEL, 1);
456 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES, features >> 32);
457 
458 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES_SEL, 0);
459 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES, features);
460 
461 	return (features);
462 }
463 
464 static int
465 vtmmio_with_feature(device_t dev, uint64_t feature)
466 {
467 	struct vtmmio_softc *sc;
468 
469 	sc = device_get_softc(dev);
470 
471 	return ((sc->vtmmio_features & feature) != 0);
472 }
473 
474 static void
475 vtmmio_set_virtqueue(struct vtmmio_softc *sc, struct virtqueue *vq,
476     uint32_t size)
477 {
478 	vm_paddr_t paddr;
479 
480 	vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_NUM, size);
481 
482 	if (sc->vtmmio_version == 1) {
483 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_ALIGN,
484 		    VIRTIO_MMIO_VRING_ALIGN);
485 		paddr = virtqueue_paddr(vq);
486 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_PFN,
487 		    paddr >> PAGE_SHIFT);
488 	} else {
489 		paddr = virtqueue_desc_paddr(vq);
490 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_DESC_LOW,
491 		    paddr);
492 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_DESC_HIGH,
493 		    ((uint64_t)paddr) >> 32);
494 
495 		paddr = virtqueue_avail_paddr(vq);
496 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_AVAIL_LOW,
497 		    paddr);
498 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_AVAIL_HIGH,
499 		    ((uint64_t)paddr) >> 32);
500 
501 		paddr = virtqueue_used_paddr(vq);
502 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_USED_LOW,
503 		    paddr);
504 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_USED_HIGH,
505 		    ((uint64_t)paddr) >> 32);
506 
507 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_READY, 1);
508 	}
509 }
510 
511 static int
512 vtmmio_alloc_virtqueues(device_t dev, int flags, int nvqs,
513     struct vq_alloc_info *vq_info)
514 {
515 	struct vtmmio_virtqueue *vqx;
516 	struct vq_alloc_info *info;
517 	struct vtmmio_softc *sc;
518 	struct virtqueue *vq;
519 	uint32_t size;
520 	int idx, error;
521 
522 	sc = device_get_softc(dev);
523 
524 	if (sc->vtmmio_nvqs != 0)
525 		return (EALREADY);
526 	if (nvqs <= 0)
527 		return (EINVAL);
528 
529 	sc->vtmmio_vqs = malloc(nvqs * sizeof(struct vtmmio_virtqueue),
530 	    M_DEVBUF, M_NOWAIT | M_ZERO);
531 	if (sc->vtmmio_vqs == NULL)
532 		return (ENOMEM);
533 
534 	if (sc->vtmmio_version == 1) {
535 		vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_PAGE_SIZE,
536 		    (1 << PAGE_SHIFT));
537 	}
538 
539 	for (idx = 0; idx < nvqs; idx++) {
540 		vqx = &sc->vtmmio_vqs[idx];
541 		info = &vq_info[idx];
542 
543 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_SEL, idx);
544 
545 		vtmmio_select_virtqueue(sc, idx);
546 		size = vtmmio_read_config_4(sc, VIRTIO_MMIO_QUEUE_NUM_MAX);
547 
548 		error = virtqueue_alloc(dev, idx, size,
549 		    VIRTIO_MMIO_QUEUE_NOTIFY, VIRTIO_MMIO_VRING_ALIGN,
550 		    ~(vm_paddr_t)0, info, &vq);
551 		if (error) {
552 			device_printf(dev,
553 			    "cannot allocate virtqueue %d: %d\n",
554 			    idx, error);
555 			break;
556 		}
557 
558 		vtmmio_set_virtqueue(sc, vq, size);
559 
560 		vqx->vtv_vq = *info->vqai_vq = vq;
561 		vqx->vtv_no_intr = info->vqai_intr == NULL;
562 
563 		sc->vtmmio_nvqs++;
564 	}
565 
566 	if (error)
567 		vtmmio_free_virtqueues(sc);
568 
569 	return (error);
570 }
571 
572 static void
573 vtmmio_stop(device_t dev)
574 {
575 
576 	vtmmio_reset(device_get_softc(dev));
577 }
578 
579 static void
580 vtmmio_poll(device_t dev)
581 {
582 	struct vtmmio_softc *sc;
583 
584 	sc = device_get_softc(dev);
585 
586 	if (sc->platform != NULL)
587 		VIRTIO_MMIO_POLL(sc->platform);
588 }
589 
590 static int
591 vtmmio_reinit(device_t dev, uint64_t features)
592 {
593 	struct vtmmio_softc *sc;
594 	int idx, error;
595 
596 	sc = device_get_softc(dev);
597 
598 	if (vtmmio_get_status(dev) != VIRTIO_CONFIG_STATUS_RESET)
599 		vtmmio_stop(dev);
600 
601 	/*
602 	 * Quickly drive the status through ACK and DRIVER. The device
603 	 * does not become usable again until vtmmio_reinit_complete().
604 	 */
605 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
606 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER);
607 
608 	vtmmio_negotiate_features(dev, features);
609 
610 	if (sc->vtmmio_version == 1) {
611 		vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_PAGE_SIZE,
612 		    (1 << PAGE_SHIFT));
613 	}
614 
615 	for (idx = 0; idx < sc->vtmmio_nvqs; idx++) {
616 		error = vtmmio_reinit_virtqueue(sc, idx);
617 		if (error)
618 			return (error);
619 	}
620 
621 	return (0);
622 }
623 
624 static void
625 vtmmio_reinit_complete(device_t dev)
626 {
627 
628 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER_OK);
629 }
630 
631 static void
632 vtmmio_notify_virtqueue(device_t dev, uint16_t queue, bus_size_t offset)
633 {
634 	struct vtmmio_softc *sc;
635 
636 	sc = device_get_softc(dev);
637 	MPASS(offset == VIRTIO_MMIO_QUEUE_NOTIFY);
638 
639 	vtmmio_write_config_4(sc, offset, queue);
640 }
641 
642 static uint8_t
643 vtmmio_get_status(device_t dev)
644 {
645 	struct vtmmio_softc *sc;
646 
647 	sc = device_get_softc(dev);
648 
649 	return (vtmmio_read_config_4(sc, VIRTIO_MMIO_STATUS));
650 }
651 
652 static void
653 vtmmio_set_status(device_t dev, uint8_t status)
654 {
655 	struct vtmmio_softc *sc;
656 
657 	sc = device_get_softc(dev);
658 
659 	if (status != VIRTIO_CONFIG_STATUS_RESET)
660 		status |= vtmmio_get_status(dev);
661 
662 	vtmmio_write_config_4(sc, VIRTIO_MMIO_STATUS, status);
663 }
664 
665 static void
666 vtmmio_read_dev_config(device_t dev, bus_size_t offset,
667     void *dst, int length)
668 {
669 	struct vtmmio_softc *sc;
670 	bus_size_t off;
671 	uint8_t *d;
672 	int size;
673 	uint64_t low32, high32;
674 
675 	sc = device_get_softc(dev);
676 	off = VIRTIO_MMIO_CONFIG + offset;
677 
678 	/*
679 	 * The non-legacy MMIO specification adds the following restriction:
680 	 *
681 	 *   4.2.2.2: For the device-specific configuration space, the driver
682 	 *   MUST use 8 bit wide accesses for 8 bit wide fields, 16 bit wide
683 	 *   and aligned accesses for 16 bit wide fields and 32 bit wide and
684 	 *   aligned accesses for 32 and 64 bit wide fields.
685 	 *
686 	 * The endianness also varies between non-legacy and legacy:
687 	 *
688 	 *   2.4: Note: The device configuration space uses the little-endian
689 	 *   format for multi-byte fields.
690 	 *
691 	 *   2.4.3: Note that for legacy interfaces, device configuration space
692 	 *   is generally the guest’s native endian, rather than PCI’s
693 	 *   little-endian. The correct endian-ness is documented for each
694 	 *   device.
695 	 */
696 	if (sc->vtmmio_version > 1) {
697 		switch (length) {
698 		case 1:
699 			*(uint8_t *)dst = vtmmio_read_config_1(sc, off);
700 			break;
701 		case 2:
702 			*(uint16_t *)dst =
703 			    le16toh(vtmmio_read_config_2(sc, off));
704 			break;
705 		case 4:
706 			*(uint32_t *)dst =
707 			    le32toh(vtmmio_read_config_4(sc, off));
708 			break;
709 		case 8:
710 			low32 = le32toh(vtmmio_read_config_4(sc, off));
711 			high32 = le32toh(vtmmio_read_config_4(sc, off + 4));
712 			*(uint64_t *)dst = (high32 << 32) | low32;
713 			break;
714 		default:
715 			panic("%s: invalid length %d\n", __func__, length);
716 		}
717 
718 		return;
719 	}
720 
721 	for (d = dst; length > 0; d += size, off += size, length -= size) {
722 #ifdef ALLOW_WORD_ALIGNED_ACCESS
723 		if (length >= 4) {
724 			size = 4;
725 			*(uint32_t *)d = vtmmio_read_config_4(sc, off);
726 		} else if (length >= 2) {
727 			size = 2;
728 			*(uint16_t *)d = vtmmio_read_config_2(sc, off);
729 		} else
730 #endif
731 		{
732 			size = 1;
733 			*d = vtmmio_read_config_1(sc, off);
734 		}
735 	}
736 }
737 
738 static void
739 vtmmio_write_dev_config(device_t dev, bus_size_t offset,
740     void *src, int length)
741 {
742 	struct vtmmio_softc *sc;
743 	bus_size_t off;
744 	uint8_t *s;
745 	int size;
746 
747 	sc = device_get_softc(dev);
748 	off = VIRTIO_MMIO_CONFIG + offset;
749 
750 	/*
751 	 * The non-legacy MMIO specification adds size and alignment
752 	 * restrctions. It also changes the endianness from native-endian to
753 	 * little-endian. See vtmmio_read_dev_config.
754 	 */
755 	if (sc->vtmmio_version > 1) {
756 		switch (length) {
757 		case 1:
758 			vtmmio_write_config_1(sc, off, *(uint8_t *)src);
759 			break;
760 		case 2:
761 			vtmmio_write_config_2(sc, off,
762 			    htole16(*(uint16_t *)src));
763 			break;
764 		case 4:
765 			vtmmio_write_config_4(sc, off,
766 			    htole32(*(uint32_t *)src));
767 			break;
768 		case 8:
769 			vtmmio_write_config_4(sc, off,
770 			    htole32(*(uint64_t *)src));
771 			vtmmio_write_config_4(sc, off + 4,
772 			    htole32((*(uint64_t *)src) >> 32));
773 			break;
774 		default:
775 			panic("%s: invalid length %d\n", __func__, length);
776 		}
777 
778 		return;
779 	}
780 
781 	for (s = src; length > 0; s += size, off += size, length -= size) {
782 #ifdef ALLOW_WORD_ALIGNED_ACCESS
783 		if (length >= 4) {
784 			size = 4;
785 			vtmmio_write_config_4(sc, off, *(uint32_t *)s);
786 		} else if (length >= 2) {
787 			size = 2;
788 			vtmmio_write_config_2(sc, off, *(uint16_t *)s);
789 		} else
790 #endif
791 		{
792 			size = 1;
793 			vtmmio_write_config_1(sc, off, *s);
794 		}
795 	}
796 }
797 
798 static void
799 vtmmio_describe_features(struct vtmmio_softc *sc, const char *msg,
800     uint64_t features)
801 {
802 	device_t dev, child;
803 
804 	dev = sc->dev;
805 	child = sc->vtmmio_child_dev;
806 
807 	if (device_is_attached(child) || bootverbose == 0)
808 		return;
809 
810 	virtio_describe(dev, msg, features, sc->vtmmio_child_feat_desc);
811 }
812 
813 static void
814 vtmmio_probe_and_attach_child(struct vtmmio_softc *sc)
815 {
816 	device_t dev, child;
817 
818 	dev = sc->dev;
819 	child = sc->vtmmio_child_dev;
820 
821 	if (child == NULL)
822 		return;
823 
824 	if (device_get_state(child) != DS_NOTPRESENT) {
825 		return;
826 	}
827 
828 	if (device_probe(child) != 0) {
829 		return;
830 	}
831 
832 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER);
833 	if (device_attach(child) != 0) {
834 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_FAILED);
835 		vtmmio_reset(sc);
836 		vtmmio_release_child_resources(sc);
837 		/* Reset status for future attempt. */
838 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
839 	} else {
840 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER_OK);
841 		VIRTIO_ATTACH_COMPLETED(child);
842 	}
843 }
844 
845 static int
846 vtmmio_reinit_virtqueue(struct vtmmio_softc *sc, int idx)
847 {
848 	struct vtmmio_virtqueue *vqx;
849 	struct virtqueue *vq;
850 	int error;
851 	uint16_t size;
852 
853 	vqx = &sc->vtmmio_vqs[idx];
854 	vq = vqx->vtv_vq;
855 
856 	KASSERT(vq != NULL, ("%s: vq %d not allocated", __func__, idx));
857 
858 	vtmmio_select_virtqueue(sc, idx);
859 	size = vtmmio_read_config_4(sc, VIRTIO_MMIO_QUEUE_NUM_MAX);
860 
861 	error = virtqueue_reinit(vq, size);
862 	if (error)
863 		return (error);
864 
865 	vtmmio_set_virtqueue(sc, vq, size);
866 
867 	return (0);
868 }
869 
870 static void
871 vtmmio_free_interrupts(struct vtmmio_softc *sc)
872 {
873 
874 	if (sc->ih != NULL)
875 		bus_teardown_intr(sc->dev, sc->res[1], sc->ih);
876 
877 	if (sc->res[1] != NULL)
878 		bus_release_resource(sc->dev, SYS_RES_IRQ, 0, sc->res[1]);
879 }
880 
881 static void
882 vtmmio_free_virtqueues(struct vtmmio_softc *sc)
883 {
884 	struct vtmmio_virtqueue *vqx;
885 	int idx;
886 
887 	for (idx = 0; idx < sc->vtmmio_nvqs; idx++) {
888 		vqx = &sc->vtmmio_vqs[idx];
889 
890 		vtmmio_select_virtqueue(sc, idx);
891 		if (sc->vtmmio_version == 1)
892 			vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_PFN, 0);
893 		else
894 			vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_READY, 0);
895 
896 		virtqueue_free(vqx->vtv_vq);
897 		vqx->vtv_vq = NULL;
898 	}
899 
900 	free(sc->vtmmio_vqs, M_DEVBUF);
901 	sc->vtmmio_vqs = NULL;
902 	sc->vtmmio_nvqs = 0;
903 }
904 
905 static void
906 vtmmio_release_child_resources(struct vtmmio_softc *sc)
907 {
908 
909 	vtmmio_free_interrupts(sc);
910 	vtmmio_free_virtqueues(sc);
911 }
912 
913 static void
914 vtmmio_reset(struct vtmmio_softc *sc)
915 {
916 
917 	/*
918 	 * Setting the status to RESET sets the host device to
919 	 * the original, uninitialized state.
920 	 */
921 	vtmmio_set_status(sc->dev, VIRTIO_CONFIG_STATUS_RESET);
922 }
923 
924 static void
925 vtmmio_select_virtqueue(struct vtmmio_softc *sc, int idx)
926 {
927 
928 	vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_SEL, idx);
929 }
930 
931 static void
932 vtmmio_vq_intr(void *arg)
933 {
934 	struct vtmmio_virtqueue *vqx;
935 	struct vtmmio_softc *sc;
936 	struct virtqueue *vq;
937 	uint32_t status;
938 	int idx;
939 
940 	sc = arg;
941 
942 	status = vtmmio_read_config_4(sc, VIRTIO_MMIO_INTERRUPT_STATUS);
943 	vtmmio_write_config_4(sc, VIRTIO_MMIO_INTERRUPT_ACK, status);
944 
945 	/* The config changed */
946 	if (status & VIRTIO_MMIO_INT_CONFIG)
947 		if (sc->vtmmio_child_dev != NULL)
948 			VIRTIO_CONFIG_CHANGE(sc->vtmmio_child_dev);
949 
950 	/* Notify all virtqueues. */
951 	if (status & VIRTIO_MMIO_INT_VRING) {
952 		for (idx = 0; idx < sc->vtmmio_nvqs; idx++) {
953 			vqx = &sc->vtmmio_vqs[idx];
954 			if (vqx->vtv_no_intr == 0) {
955 				vq = vqx->vtv_vq;
956 				virtqueue_intr(vq);
957 			}
958 		}
959 	}
960 }
961