xref: /freebsd/sys/dev/virtio/mmio/virtio_mmio.c (revision d9a42747950146bf03cda7f6e25d219253f8a57a)
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_finalize_features(device_t);
78 static int	vtmmio_with_feature(device_t, uint64_t);
79 static void	vtmmio_set_virtqueue(struct vtmmio_softc *sc,
80 		    struct virtqueue *vq, uint32_t size);
81 static int	vtmmio_alloc_virtqueues(device_t, int, int,
82 		    struct vq_alloc_info *);
83 static int	vtmmio_setup_intr(device_t, enum intr_type);
84 static void	vtmmio_stop(device_t);
85 static void	vtmmio_poll(device_t);
86 static int	vtmmio_reinit(device_t, uint64_t);
87 static void	vtmmio_reinit_complete(device_t);
88 static void	vtmmio_notify_virtqueue(device_t, uint16_t, bus_size_t);
89 static int	vtmmio_config_generation(device_t);
90 static uint8_t	vtmmio_get_status(device_t);
91 static void	vtmmio_set_status(device_t, uint8_t);
92 static void	vtmmio_read_dev_config(device_t, bus_size_t, void *, int);
93 static uint64_t	vtmmio_read_dev_config_8(struct vtmmio_softc *, bus_size_t);
94 static void	vtmmio_write_dev_config(device_t, bus_size_t, const void *, int);
95 static void	vtmmio_describe_features(struct vtmmio_softc *, const char *,
96 		    uint64_t);
97 static void	vtmmio_probe_and_attach_child(struct vtmmio_softc *);
98 static int	vtmmio_reinit_virtqueue(struct vtmmio_softc *, int);
99 static void	vtmmio_free_interrupts(struct vtmmio_softc *);
100 static void	vtmmio_free_virtqueues(struct vtmmio_softc *);
101 static void	vtmmio_release_child_resources(struct vtmmio_softc *);
102 static void	vtmmio_reset(struct vtmmio_softc *);
103 static void	vtmmio_select_virtqueue(struct vtmmio_softc *, int);
104 static void	vtmmio_vq_intr(void *);
105 
106 /*
107  * I/O port read/write wrappers.
108  */
109 #define vtmmio_write_config_1(sc, o, v)				\
110 do {								\
111 	if (sc->platform != NULL)				\
112 		VIRTIO_MMIO_PREWRITE(sc->platform, (o), (v));	\
113 	bus_write_1((sc)->res[0], (o), (v)); 			\
114 	if (sc->platform != NULL)				\
115 		VIRTIO_MMIO_NOTE(sc->platform, (o), (v));	\
116 } while (0)
117 #define vtmmio_write_config_2(sc, o, v)				\
118 do {								\
119 	if (sc->platform != NULL)				\
120 		VIRTIO_MMIO_PREWRITE(sc->platform, (o), (v));	\
121 	bus_write_2((sc)->res[0], (o), (v));			\
122 	if (sc->platform != NULL)				\
123 		VIRTIO_MMIO_NOTE(sc->platform, (o), (v));	\
124 } while (0)
125 #define vtmmio_write_config_4(sc, o, v)				\
126 do {								\
127 	if (sc->platform != NULL)				\
128 		VIRTIO_MMIO_PREWRITE(sc->platform, (o), (v));	\
129 	bus_write_4((sc)->res[0], (o), (v));			\
130 	if (sc->platform != NULL)				\
131 		VIRTIO_MMIO_NOTE(sc->platform, (o), (v));	\
132 } while (0)
133 
134 #define vtmmio_read_config_1(sc, o) \
135 	bus_read_1((sc)->res[0], (o))
136 #define vtmmio_read_config_2(sc, o) \
137 	bus_read_2((sc)->res[0], (o))
138 #define vtmmio_read_config_4(sc, o) \
139 	bus_read_4((sc)->res[0], (o))
140 
141 static device_method_t vtmmio_methods[] = {
142 	/* Device interface. */
143 	DEVMETHOD(device_attach,		  vtmmio_attach),
144 	DEVMETHOD(device_detach,		  vtmmio_detach),
145 	DEVMETHOD(device_suspend,		  vtmmio_suspend),
146 	DEVMETHOD(device_resume,		  vtmmio_resume),
147 	DEVMETHOD(device_shutdown,		  vtmmio_shutdown),
148 
149 	/* Bus interface. */
150 	DEVMETHOD(bus_driver_added,		  vtmmio_driver_added),
151 	DEVMETHOD(bus_child_detached,		  vtmmio_child_detached),
152 	DEVMETHOD(bus_child_pnpinfo,		  virtio_child_pnpinfo),
153 	DEVMETHOD(bus_read_ivar,		  vtmmio_read_ivar),
154 	DEVMETHOD(bus_write_ivar,		  vtmmio_write_ivar),
155 
156 	/* VirtIO bus interface. */
157 	DEVMETHOD(virtio_bus_negotiate_features,  vtmmio_negotiate_features),
158 	DEVMETHOD(virtio_bus_finalize_features,	  vtmmio_finalize_features),
159 	DEVMETHOD(virtio_bus_with_feature,	  vtmmio_with_feature),
160 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtmmio_alloc_virtqueues),
161 	DEVMETHOD(virtio_bus_setup_intr,	  vtmmio_setup_intr),
162 	DEVMETHOD(virtio_bus_stop,		  vtmmio_stop),
163 	DEVMETHOD(virtio_bus_poll,		  vtmmio_poll),
164 	DEVMETHOD(virtio_bus_reinit,		  vtmmio_reinit),
165 	DEVMETHOD(virtio_bus_reinit_complete,	  vtmmio_reinit_complete),
166 	DEVMETHOD(virtio_bus_notify_vq,		  vtmmio_notify_virtqueue),
167 	DEVMETHOD(virtio_bus_config_generation,	  vtmmio_config_generation),
168 	DEVMETHOD(virtio_bus_read_device_config,  vtmmio_read_dev_config),
169 	DEVMETHOD(virtio_bus_write_device_config, vtmmio_write_dev_config),
170 
171 	DEVMETHOD_END
172 };
173 
174 DEFINE_CLASS_0(virtio_mmio, vtmmio_driver, vtmmio_methods,
175     sizeof(struct vtmmio_softc));
176 
177 MODULE_VERSION(virtio_mmio, 1);
178 
179 int
180 vtmmio_probe(device_t dev)
181 {
182 	struct vtmmio_softc *sc;
183 	int rid;
184 	uint32_t magic, version;
185 
186 	sc = device_get_softc(dev);
187 
188 	rid = 0;
189 	sc->res[0] = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
190 	    RF_ACTIVE);
191 	if (sc->res[0] == NULL) {
192 		device_printf(dev, "Cannot allocate memory window.\n");
193 		return (ENXIO);
194 	}
195 
196 	magic = vtmmio_read_config_4(sc, VIRTIO_MMIO_MAGIC_VALUE);
197 	if (magic != VIRTIO_MMIO_MAGIC_VIRT) {
198 		device_printf(dev, "Bad magic value %#x\n", magic);
199 		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
200 		return (ENXIO);
201 	}
202 
203 	version = vtmmio_read_config_4(sc, VIRTIO_MMIO_VERSION);
204 	if (version < 1 || version > 2) {
205 		device_printf(dev, "Unsupported version: %#x\n", version);
206 		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
207 		return (ENXIO);
208 	}
209 
210 	if (vtmmio_read_config_4(sc, VIRTIO_MMIO_DEVICE_ID) == 0) {
211 		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
212 		return (ENXIO);
213 	}
214 
215 	bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res[0]);
216 
217 	device_set_desc(dev, "VirtIO MMIO adapter");
218 	return (BUS_PROBE_DEFAULT);
219 }
220 
221 static int
222 vtmmio_setup_intr(device_t dev, enum intr_type type)
223 {
224 	struct vtmmio_softc *sc;
225 	int rid;
226 	int err;
227 
228 	sc = device_get_softc(dev);
229 
230 	if (sc->platform != NULL) {
231 		err = VIRTIO_MMIO_SETUP_INTR(sc->platform, sc->dev,
232 					vtmmio_vq_intr, sc);
233 		if (err == 0) {
234 			/* Okay we have backend-specific interrupts */
235 			return (0);
236 		}
237 	}
238 
239 	rid = 0;
240 	sc->res[1] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
241 		RF_ACTIVE);
242 	if (!sc->res[1]) {
243 		device_printf(dev, "Can't allocate interrupt\n");
244 		return (ENXIO);
245 	}
246 
247 	if (bus_setup_intr(dev, sc->res[1], type | INTR_MPSAFE,
248 		NULL, vtmmio_vq_intr, sc, &sc->ih)) {
249 		device_printf(dev, "Can't setup the interrupt\n");
250 		return (ENXIO);
251 	}
252 
253 	return (0);
254 }
255 
256 int
257 vtmmio_attach(device_t dev)
258 {
259 	struct vtmmio_softc *sc;
260 	device_t child;
261 	int rid;
262 
263 	sc = device_get_softc(dev);
264 	sc->dev = dev;
265 
266 	rid = 0;
267 	sc->res[0] = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
268 			RF_ACTIVE);
269 	if (sc->res[0] == NULL) {
270 		device_printf(dev, "Cannot allocate memory window.\n");
271 		return (ENXIO);
272 	}
273 
274 	sc->vtmmio_version = vtmmio_read_config_4(sc, VIRTIO_MMIO_VERSION);
275 
276 	vtmmio_reset(sc);
277 
278 	/* Tell the host we've noticed this device. */
279 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
280 
281 	if ((child = device_add_child(dev, NULL, -1)) == NULL) {
282 		device_printf(dev, "Cannot create child device.\n");
283 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_FAILED);
284 		vtmmio_detach(dev);
285 		return (ENOMEM);
286 	}
287 
288 	sc->vtmmio_child_dev = child;
289 	vtmmio_probe_and_attach_child(sc);
290 
291 	return (0);
292 }
293 
294 static int
295 vtmmio_detach(device_t dev)
296 {
297 	struct vtmmio_softc *sc;
298 	device_t child;
299 	int error;
300 
301 	sc = device_get_softc(dev);
302 
303 	if ((child = sc->vtmmio_child_dev) != NULL) {
304 		error = device_delete_child(dev, child);
305 		if (error)
306 			return (error);
307 		sc->vtmmio_child_dev = NULL;
308 	}
309 
310 	vtmmio_reset(sc);
311 
312 	if (sc->res[0] != NULL) {
313 		bus_release_resource(dev, SYS_RES_MEMORY, 0,
314 		    sc->res[0]);
315 		sc->res[0] = NULL;
316 	}
317 
318 	return (0);
319 }
320 
321 static int
322 vtmmio_suspend(device_t dev)
323 {
324 
325 	return (bus_generic_suspend(dev));
326 }
327 
328 static int
329 vtmmio_resume(device_t dev)
330 {
331 
332 	return (bus_generic_resume(dev));
333 }
334 
335 static int
336 vtmmio_shutdown(device_t dev)
337 {
338 
339 	(void) bus_generic_shutdown(dev);
340 
341 	/* Forcibly stop the host device. */
342 	vtmmio_stop(dev);
343 
344 	return (0);
345 }
346 
347 static void
348 vtmmio_driver_added(device_t dev, driver_t *driver)
349 {
350 	struct vtmmio_softc *sc;
351 
352 	sc = device_get_softc(dev);
353 
354 	vtmmio_probe_and_attach_child(sc);
355 }
356 
357 static void
358 vtmmio_child_detached(device_t dev, device_t child)
359 {
360 	struct vtmmio_softc *sc;
361 
362 	sc = device_get_softc(dev);
363 
364 	vtmmio_reset(sc);
365 	vtmmio_release_child_resources(sc);
366 }
367 
368 static int
369 vtmmio_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
370 {
371 	struct vtmmio_softc *sc;
372 
373 	sc = device_get_softc(dev);
374 
375 	if (sc->vtmmio_child_dev != child)
376 		return (ENOENT);
377 
378 	switch (index) {
379 	case VIRTIO_IVAR_DEVTYPE:
380 	case VIRTIO_IVAR_SUBDEVICE:
381 		*result = vtmmio_read_config_4(sc, VIRTIO_MMIO_DEVICE_ID);
382 		break;
383 	case VIRTIO_IVAR_VENDOR:
384 		*result = vtmmio_read_config_4(sc, VIRTIO_MMIO_VENDOR_ID);
385 		break;
386 	case VIRTIO_IVAR_SUBVENDOR:
387 	case VIRTIO_IVAR_DEVICE:
388 		/*
389 		 * Dummy value for fields not present in this bus.  Used by
390 		 * bus-agnostic virtio_child_pnpinfo.
391 		 */
392 		*result = 0;
393 		break;
394 	case VIRTIO_IVAR_MODERN:
395 		/*
396 		 * There are several modern (aka MMIO v2) spec compliance
397 		 * issues with this driver, but keep the status quo.
398 		 */
399 		*result = sc->vtmmio_version > 1;
400 		break;
401 	default:
402 		return (ENOENT);
403 	}
404 
405 	return (0);
406 }
407 
408 static int
409 vtmmio_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
410 {
411 	struct vtmmio_softc *sc;
412 
413 	sc = device_get_softc(dev);
414 
415 	if (sc->vtmmio_child_dev != child)
416 		return (ENOENT);
417 
418 	switch (index) {
419 	case VIRTIO_IVAR_FEATURE_DESC:
420 		sc->vtmmio_child_feat_desc = (void *) value;
421 		break;
422 	default:
423 		return (ENOENT);
424 	}
425 
426 	return (0);
427 }
428 
429 static uint64_t
430 vtmmio_negotiate_features(device_t dev, uint64_t child_features)
431 {
432 	struct vtmmio_softc *sc;
433 	uint64_t host_features, features;
434 
435 	sc = device_get_softc(dev);
436 
437 	if (sc->vtmmio_version > 1) {
438 		child_features |= VIRTIO_F_VERSION_1;
439 	}
440 
441 	vtmmio_write_config_4(sc, VIRTIO_MMIO_HOST_FEATURES_SEL, 1);
442 	host_features = vtmmio_read_config_4(sc, VIRTIO_MMIO_HOST_FEATURES);
443 	host_features <<= 32;
444 
445 	vtmmio_write_config_4(sc, VIRTIO_MMIO_HOST_FEATURES_SEL, 0);
446 	host_features |= vtmmio_read_config_4(sc, VIRTIO_MMIO_HOST_FEATURES);
447 
448 	vtmmio_describe_features(sc, "host", host_features);
449 
450 	/*
451 	 * Limit negotiated features to what the driver, virtqueue, and
452 	 * host all support.
453 	 */
454 	features = host_features & child_features;
455 	features = virtio_filter_transport_features(features);
456 	sc->vtmmio_features = features;
457 
458 	vtmmio_describe_features(sc, "negotiated", features);
459 
460 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES_SEL, 1);
461 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES, features >> 32);
462 
463 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES_SEL, 0);
464 	vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_FEATURES, features);
465 
466 	return (features);
467 }
468 
469 static int
470 vtmmio_finalize_features(device_t dev)
471 {
472 	struct vtmmio_softc *sc;
473 	uint8_t status;
474 
475 	sc = device_get_softc(dev);
476 
477 	if (sc->vtmmio_version > 1) {
478 		/*
479 		 * Must re-read the status after setting it to verify the
480 		 * negotiated features were accepted by the device.
481 		 */
482 		vtmmio_set_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
483 
484 		status = vtmmio_get_status(dev);
485 		if ((status & VIRTIO_CONFIG_S_FEATURES_OK) == 0) {
486 			device_printf(dev, "desired features were not accepted\n");
487 			return (ENOTSUP);
488 		}
489 	}
490 
491 	return (0);
492 }
493 
494 static int
495 vtmmio_with_feature(device_t dev, uint64_t feature)
496 {
497 	struct vtmmio_softc *sc;
498 
499 	sc = device_get_softc(dev);
500 
501 	return ((sc->vtmmio_features & feature) != 0);
502 }
503 
504 static void
505 vtmmio_set_virtqueue(struct vtmmio_softc *sc, struct virtqueue *vq,
506     uint32_t size)
507 {
508 	vm_paddr_t paddr;
509 
510 	vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_NUM, size);
511 
512 	if (sc->vtmmio_version == 1) {
513 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_ALIGN,
514 		    VIRTIO_MMIO_VRING_ALIGN);
515 		paddr = virtqueue_paddr(vq);
516 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_PFN,
517 		    paddr >> PAGE_SHIFT);
518 	} else {
519 		paddr = virtqueue_desc_paddr(vq);
520 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_DESC_LOW,
521 		    paddr);
522 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_DESC_HIGH,
523 		    ((uint64_t)paddr) >> 32);
524 
525 		paddr = virtqueue_avail_paddr(vq);
526 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_AVAIL_LOW,
527 		    paddr);
528 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_AVAIL_HIGH,
529 		    ((uint64_t)paddr) >> 32);
530 
531 		paddr = virtqueue_used_paddr(vq);
532 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_USED_LOW,
533 		    paddr);
534 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_USED_HIGH,
535 		    ((uint64_t)paddr) >> 32);
536 
537 		vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_READY, 1);
538 	}
539 }
540 
541 static int
542 vtmmio_alloc_virtqueues(device_t dev, int flags, int nvqs,
543     struct vq_alloc_info *vq_info)
544 {
545 	struct vtmmio_virtqueue *vqx;
546 	struct vq_alloc_info *info;
547 	struct vtmmio_softc *sc;
548 	struct virtqueue *vq;
549 	uint32_t size;
550 	int idx, error;
551 
552 	sc = device_get_softc(dev);
553 
554 	if (sc->vtmmio_nvqs != 0)
555 		return (EALREADY);
556 	if (nvqs <= 0)
557 		return (EINVAL);
558 
559 	sc->vtmmio_vqs = malloc(nvqs * sizeof(struct vtmmio_virtqueue),
560 	    M_DEVBUF, M_NOWAIT | M_ZERO);
561 	if (sc->vtmmio_vqs == NULL)
562 		return (ENOMEM);
563 
564 	if (sc->vtmmio_version == 1) {
565 		vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_PAGE_SIZE,
566 		    (1 << PAGE_SHIFT));
567 	}
568 
569 	for (idx = 0; idx < nvqs; idx++) {
570 		vqx = &sc->vtmmio_vqs[idx];
571 		info = &vq_info[idx];
572 
573 		vtmmio_select_virtqueue(sc, idx);
574 		size = vtmmio_read_config_4(sc, VIRTIO_MMIO_QUEUE_NUM_MAX);
575 
576 		error = virtqueue_alloc(dev, idx, size,
577 		    VIRTIO_MMIO_QUEUE_NOTIFY, VIRTIO_MMIO_VRING_ALIGN,
578 		    ~(vm_paddr_t)0, info, &vq);
579 		if (error) {
580 			device_printf(dev,
581 			    "cannot allocate virtqueue %d: %d\n",
582 			    idx, error);
583 			break;
584 		}
585 
586 		vtmmio_set_virtqueue(sc, vq, size);
587 
588 		vqx->vtv_vq = *info->vqai_vq = vq;
589 		vqx->vtv_no_intr = info->vqai_intr == NULL;
590 
591 		sc->vtmmio_nvqs++;
592 	}
593 
594 	if (error)
595 		vtmmio_free_virtqueues(sc);
596 
597 	return (error);
598 }
599 
600 static void
601 vtmmio_stop(device_t dev)
602 {
603 
604 	vtmmio_reset(device_get_softc(dev));
605 }
606 
607 static void
608 vtmmio_poll(device_t dev)
609 {
610 	struct vtmmio_softc *sc;
611 
612 	sc = device_get_softc(dev);
613 
614 	if (sc->platform != NULL)
615 		VIRTIO_MMIO_POLL(sc->platform);
616 }
617 
618 static int
619 vtmmio_reinit(device_t dev, uint64_t features)
620 {
621 	struct vtmmio_softc *sc;
622 	int idx, error;
623 
624 	sc = device_get_softc(dev);
625 
626 	if (vtmmio_get_status(dev) != VIRTIO_CONFIG_STATUS_RESET)
627 		vtmmio_stop(dev);
628 
629 	/*
630 	 * Quickly drive the status through ACK and DRIVER. The device
631 	 * does not become usable again until vtmmio_reinit_complete().
632 	 */
633 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
634 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER);
635 
636 	/*
637 	 * TODO: Check that features are not added as to what was
638 	 * originally negotiated.
639 	 */
640 	vtmmio_negotiate_features(dev, features);
641 	error = vtmmio_finalize_features(dev);
642 	if (error) {
643 		device_printf(dev, "cannot finalize features during reinit\n");
644 		return (error);
645 	}
646 
647 	if (sc->vtmmio_version == 1) {
648 		vtmmio_write_config_4(sc, VIRTIO_MMIO_GUEST_PAGE_SIZE,
649 		    (1 << PAGE_SHIFT));
650 	}
651 
652 	for (idx = 0; idx < sc->vtmmio_nvqs; idx++) {
653 		error = vtmmio_reinit_virtqueue(sc, idx);
654 		if (error)
655 			return (error);
656 	}
657 
658 	return (0);
659 }
660 
661 static void
662 vtmmio_reinit_complete(device_t dev)
663 {
664 
665 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER_OK);
666 }
667 
668 static void
669 vtmmio_notify_virtqueue(device_t dev, uint16_t queue, bus_size_t offset)
670 {
671 	struct vtmmio_softc *sc;
672 
673 	sc = device_get_softc(dev);
674 	MPASS(offset == VIRTIO_MMIO_QUEUE_NOTIFY);
675 
676 	vtmmio_write_config_4(sc, offset, queue);
677 }
678 
679 static int
680 vtmmio_config_generation(device_t dev)
681 {
682 	struct vtmmio_softc *sc;
683 	uint32_t gen;
684 
685 	sc = device_get_softc(dev);
686 
687 	if (sc->vtmmio_version > 1)
688 		gen = vtmmio_read_config_4(sc, VIRTIO_MMIO_CONFIG_GENERATION);
689 	else
690 		gen = 0;
691 
692 	return (gen);
693 }
694 
695 static uint8_t
696 vtmmio_get_status(device_t dev)
697 {
698 	struct vtmmio_softc *sc;
699 
700 	sc = device_get_softc(dev);
701 
702 	return (vtmmio_read_config_4(sc, VIRTIO_MMIO_STATUS));
703 }
704 
705 static void
706 vtmmio_set_status(device_t dev, uint8_t status)
707 {
708 	struct vtmmio_softc *sc;
709 
710 	sc = device_get_softc(dev);
711 
712 	if (status != VIRTIO_CONFIG_STATUS_RESET)
713 		status |= vtmmio_get_status(dev);
714 
715 	vtmmio_write_config_4(sc, VIRTIO_MMIO_STATUS, status);
716 }
717 
718 static void
719 vtmmio_read_dev_config(device_t dev, bus_size_t offset,
720     void *dst, int length)
721 {
722 	struct vtmmio_softc *sc;
723 	bus_size_t off;
724 	uint8_t *d;
725 	int size;
726 
727 	sc = device_get_softc(dev);
728 	off = VIRTIO_MMIO_CONFIG + offset;
729 
730 	/*
731 	 * The non-legacy MMIO specification adds the following restriction:
732 	 *
733 	 *   4.2.2.2: For the device-specific configuration space, the driver
734 	 *   MUST use 8 bit wide accesses for 8 bit wide fields, 16 bit wide
735 	 *   and aligned accesses for 16 bit wide fields and 32 bit wide and
736 	 *   aligned accesses for 32 and 64 bit wide fields.
737 	 *
738 	 * The endianness also varies between non-legacy and legacy:
739 	 *
740 	 *   2.4: Note: The device configuration space uses the little-endian
741 	 *   format for multi-byte fields.
742 	 *
743 	 *   2.4.3: Note that for legacy interfaces, device configuration space
744 	 *   is generally the guest’s native endian, rather than PCI’s
745 	 *   little-endian. The correct endian-ness is documented for each
746 	 *   device.
747 	 */
748 	if (sc->vtmmio_version > 1) {
749 		switch (length) {
750 		case 1:
751 			*(uint8_t *)dst = vtmmio_read_config_1(sc, off);
752 			break;
753 		case 2:
754 			*(uint16_t *)dst =
755 			    le16toh(vtmmio_read_config_2(sc, off));
756 			break;
757 		case 4:
758 			*(uint32_t *)dst =
759 			    le32toh(vtmmio_read_config_4(sc, off));
760 			break;
761 		case 8:
762 			*(uint64_t *)dst = vtmmio_read_dev_config_8(sc, off);
763 			break;
764 		default:
765 			panic("%s: invalid length %d\n", __func__, length);
766 		}
767 
768 		return;
769 	}
770 
771 	for (d = dst; length > 0; d += size, off += size, length -= size) {
772 #ifdef ALLOW_WORD_ALIGNED_ACCESS
773 		if (length >= 4) {
774 			size = 4;
775 			*(uint32_t *)d = vtmmio_read_config_4(sc, off);
776 		} else if (length >= 2) {
777 			size = 2;
778 			*(uint16_t *)d = vtmmio_read_config_2(sc, off);
779 		} else
780 #endif
781 		{
782 			size = 1;
783 			*d = vtmmio_read_config_1(sc, off);
784 		}
785 	}
786 }
787 
788 static uint64_t
789 vtmmio_read_dev_config_8(struct vtmmio_softc *sc, bus_size_t off)
790 {
791 	device_t dev;
792 	int gen;
793 	uint32_t val0, val1;
794 
795 	dev = sc->dev;
796 
797 	do {
798 		gen = vtmmio_config_generation(dev);
799 		val0 = le32toh(vtmmio_read_config_4(sc, off));
800 		val1 = le32toh(vtmmio_read_config_4(sc, off + 4));
801 	} while (gen != vtmmio_config_generation(dev));
802 
803 	return (((uint64_t) val1 << 32) | val0);
804 }
805 
806 static void
807 vtmmio_write_dev_config(device_t dev, bus_size_t offset,
808     const void *src, int length)
809 {
810 	struct vtmmio_softc *sc;
811 	bus_size_t off;
812 	const uint8_t *s;
813 	int size;
814 
815 	sc = device_get_softc(dev);
816 	off = VIRTIO_MMIO_CONFIG + offset;
817 
818 	/*
819 	 * The non-legacy MMIO specification adds size and alignment
820 	 * restrctions. It also changes the endianness from native-endian to
821 	 * little-endian. See vtmmio_read_dev_config.
822 	 */
823 	if (sc->vtmmio_version > 1) {
824 		switch (length) {
825 		case 1:
826 			vtmmio_write_config_1(sc, off, *(const uint8_t *)src);
827 			break;
828 		case 2:
829 			vtmmio_write_config_2(sc, off,
830 			    htole16(*(const uint16_t *)src));
831 			break;
832 		case 4:
833 			vtmmio_write_config_4(sc, off,
834 			    htole32(*(const uint32_t *)src));
835 			break;
836 		case 8:
837 			vtmmio_write_config_4(sc, off,
838 			    htole32(*(const uint64_t *)src));
839 			vtmmio_write_config_4(sc, off + 4,
840 			    htole32((*(const uint64_t *)src) >> 32));
841 			break;
842 		default:
843 			panic("%s: invalid length %d\n", __func__, length);
844 		}
845 
846 		return;
847 	}
848 
849 	for (s = src; length > 0; s += size, off += size, length -= size) {
850 #ifdef ALLOW_WORD_ALIGNED_ACCESS
851 		if (length >= 4) {
852 			size = 4;
853 			vtmmio_write_config_4(sc, off, *(uint32_t *)s);
854 		} else if (length >= 2) {
855 			size = 2;
856 			vtmmio_write_config_2(sc, off, *(uint16_t *)s);
857 		} else
858 #endif
859 		{
860 			size = 1;
861 			vtmmio_write_config_1(sc, off, *s);
862 		}
863 	}
864 }
865 
866 static void
867 vtmmio_describe_features(struct vtmmio_softc *sc, const char *msg,
868     uint64_t features)
869 {
870 	device_t dev, child;
871 
872 	dev = sc->dev;
873 	child = sc->vtmmio_child_dev;
874 
875 	if (device_is_attached(child) || bootverbose == 0)
876 		return;
877 
878 	virtio_describe(dev, msg, features, sc->vtmmio_child_feat_desc);
879 }
880 
881 static void
882 vtmmio_probe_and_attach_child(struct vtmmio_softc *sc)
883 {
884 	device_t dev, child;
885 
886 	dev = sc->dev;
887 	child = sc->vtmmio_child_dev;
888 
889 	if (child == NULL)
890 		return;
891 
892 	if (device_get_state(child) != DS_NOTPRESENT) {
893 		return;
894 	}
895 
896 	if (device_probe(child) != 0) {
897 		return;
898 	}
899 
900 	vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER);
901 	if (device_attach(child) != 0) {
902 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_FAILED);
903 		vtmmio_reset(sc);
904 		vtmmio_release_child_resources(sc);
905 		/* Reset status for future attempt. */
906 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_ACK);
907 	} else {
908 		vtmmio_set_status(dev, VIRTIO_CONFIG_STATUS_DRIVER_OK);
909 		VIRTIO_ATTACH_COMPLETED(child);
910 	}
911 }
912 
913 static int
914 vtmmio_reinit_virtqueue(struct vtmmio_softc *sc, int idx)
915 {
916 	struct vtmmio_virtqueue *vqx;
917 	struct virtqueue *vq;
918 	int error;
919 	uint16_t size;
920 
921 	vqx = &sc->vtmmio_vqs[idx];
922 	vq = vqx->vtv_vq;
923 
924 	KASSERT(vq != NULL, ("%s: vq %d not allocated", __func__, idx));
925 
926 	vtmmio_select_virtqueue(sc, idx);
927 	size = vtmmio_read_config_4(sc, VIRTIO_MMIO_QUEUE_NUM_MAX);
928 
929 	error = virtqueue_reinit(vq, size);
930 	if (error)
931 		return (error);
932 
933 	vtmmio_set_virtqueue(sc, vq, size);
934 
935 	return (0);
936 }
937 
938 static void
939 vtmmio_free_interrupts(struct vtmmio_softc *sc)
940 {
941 
942 	if (sc->ih != NULL)
943 		bus_teardown_intr(sc->dev, sc->res[1], sc->ih);
944 
945 	if (sc->res[1] != NULL)
946 		bus_release_resource(sc->dev, SYS_RES_IRQ, 0, sc->res[1]);
947 }
948 
949 static void
950 vtmmio_free_virtqueues(struct vtmmio_softc *sc)
951 {
952 	struct vtmmio_virtqueue *vqx;
953 	int idx;
954 
955 	for (idx = 0; idx < sc->vtmmio_nvqs; idx++) {
956 		vqx = &sc->vtmmio_vqs[idx];
957 
958 		vtmmio_select_virtqueue(sc, idx);
959 		if (sc->vtmmio_version > 1) {
960 			vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_READY, 0);
961 			vtmmio_read_config_4(sc, VIRTIO_MMIO_QUEUE_READY);
962 		} else
963 			vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_PFN, 0);
964 
965 		virtqueue_free(vqx->vtv_vq);
966 		vqx->vtv_vq = NULL;
967 	}
968 
969 	free(sc->vtmmio_vqs, M_DEVBUF);
970 	sc->vtmmio_vqs = NULL;
971 	sc->vtmmio_nvqs = 0;
972 }
973 
974 static void
975 vtmmio_release_child_resources(struct vtmmio_softc *sc)
976 {
977 
978 	vtmmio_free_interrupts(sc);
979 	vtmmio_free_virtqueues(sc);
980 }
981 
982 static void
983 vtmmio_reset(struct vtmmio_softc *sc)
984 {
985 
986 	/*
987 	 * Setting the status to RESET sets the host device to
988 	 * the original, uninitialized state.
989 	 */
990 	vtmmio_set_status(sc->dev, VIRTIO_CONFIG_STATUS_RESET);
991 }
992 
993 static void
994 vtmmio_select_virtqueue(struct vtmmio_softc *sc, int idx)
995 {
996 
997 	vtmmio_write_config_4(sc, VIRTIO_MMIO_QUEUE_SEL, idx);
998 }
999 
1000 static void
1001 vtmmio_vq_intr(void *arg)
1002 {
1003 	struct vtmmio_virtqueue *vqx;
1004 	struct vtmmio_softc *sc;
1005 	struct virtqueue *vq;
1006 	uint32_t status;
1007 	int idx;
1008 
1009 	sc = arg;
1010 
1011 	status = vtmmio_read_config_4(sc, VIRTIO_MMIO_INTERRUPT_STATUS);
1012 	vtmmio_write_config_4(sc, VIRTIO_MMIO_INTERRUPT_ACK, status);
1013 
1014 	/* The config changed */
1015 	if (status & VIRTIO_MMIO_INT_CONFIG)
1016 		if (sc->vtmmio_child_dev != NULL)
1017 			VIRTIO_CONFIG_CHANGE(sc->vtmmio_child_dev);
1018 
1019 	/* Notify all virtqueues. */
1020 	if (status & VIRTIO_MMIO_INT_VRING) {
1021 		for (idx = 0; idx < sc->vtmmio_nvqs; idx++) {
1022 			vqx = &sc->vtmmio_vqs[idx];
1023 			if (vqx->vtv_no_intr == 0) {
1024 				vq = vqx->vtv_vq;
1025 				virtqueue_intr(vq);
1026 			}
1027 		}
1028 	}
1029 }
1030