1 /*
2  * Virtio PCI driver - modern (virtio 1.0) device support
3  *
4  * This module allows virtio devices to be used over a virtual PCI device.
5  * This can be used with QEMU based VMMs like KVM or Xen.
6  *
7  * Copyright IBM Corp. 2007
8  * Copyright Red Hat, Inc. 2014
9  *
10  * Authors:
11  *  Anthony Liguori  <aliguori@us.ibm.com>
12  *  Rusty Russell <rusty@rustcorp.com.au>
13  *  Michael S. Tsirkin <mst@redhat.com>
14  *
15  * This work is licensed under the terms of the GNU GPL, version 2 or later.
16  * See the COPYING file in the top-level directory.
17  *
18  */
19 
20 #define VIRTIO_PCI_NO_LEGACY
21 #include "virtio_pci_common.h"
22 
23 static void __iomem *map_capability(struct pci_dev *dev, int off,
24 				    size_t minlen,
25 				    u32 align,
26 				    u32 start, u32 size,
27 				    size_t *len)
28 {
29 	u8 bar;
30 	u32 offset, length;
31 	void __iomem *p;
32 
33 	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
34 						 bar),
35 			     &bar);
36 	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
37 			     &offset);
38 	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
39 			      &length);
40 
41 	if (length <= start) {
42 		dev_err(&dev->dev,
43 			"virtio_pci: bad capability len %u (>%u expected)\n",
44 			length, start);
45 		return NULL;
46 	}
47 
48 	if (length - start < minlen) {
49 		dev_err(&dev->dev,
50 			"virtio_pci: bad capability len %u (>=%zu expected)\n",
51 			length, minlen);
52 		return NULL;
53 	}
54 
55 	length -= start;
56 
57 	if (start + offset < offset) {
58 		dev_err(&dev->dev,
59 			"virtio_pci: map wrap-around %u+%u\n",
60 			start, offset);
61 		return NULL;
62 	}
63 
64 	offset += start;
65 
66 	if (offset & (align - 1)) {
67 		dev_err(&dev->dev,
68 			"virtio_pci: offset %u not aligned to %u\n",
69 			offset, align);
70 		return NULL;
71 	}
72 
73 	if (length > size)
74 		length = size;
75 
76 	if (len)
77 		*len = length;
78 
79 	if (minlen + offset < minlen ||
80 	    minlen + offset > pci_resource_len(dev, bar)) {
81 		dev_err(&dev->dev,
82 			"virtio_pci: map virtio %zu@%u "
83 			"out of range on bar %i length %lu\n",
84 			minlen, offset,
85 			bar, (unsigned long)pci_resource_len(dev, bar));
86 		return NULL;
87 	}
88 
89 	p = pci_iomap_range(dev, bar, offset, length);
90 	if (!p)
91 		dev_err(&dev->dev,
92 			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
93 			length, offset, bar);
94 	return p;
95 }
96 
97 static void iowrite64_twopart(u64 val, __le32 __iomem *lo, __le32 __iomem *hi)
98 {
99 	iowrite32((u32)val, lo);
100 	iowrite32(val >> 32, hi);
101 }
102 
103 /* virtio config->get_features() implementation */
104 static u64 vp_get_features(struct virtio_device *vdev)
105 {
106 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
107 	u64 features;
108 
109 	iowrite32(0, &vp_dev->common->device_feature_select);
110 	features = ioread32(&vp_dev->common->device_feature);
111 	iowrite32(1, &vp_dev->common->device_feature_select);
112 	features |= ((u64)ioread32(&vp_dev->common->device_feature) << 32);
113 
114 	return features;
115 }
116 
117 /* virtio config->finalize_features() implementation */
118 static int vp_finalize_features(struct virtio_device *vdev)
119 {
120 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
121 
122 	/* Give virtio_ring a chance to accept features. */
123 	vring_transport_features(vdev);
124 
125 	if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
126 		dev_err(&vdev->dev, "virtio: device uses modern interface "
127 			"but does not have VIRTIO_F_VERSION_1\n");
128 		return -EINVAL;
129 	}
130 
131 	iowrite32(0, &vp_dev->common->guest_feature_select);
132 	iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
133 	iowrite32(1, &vp_dev->common->guest_feature_select);
134 	iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
135 
136 	return 0;
137 }
138 
139 /* virtio config->get() implementation */
140 static void vp_get(struct virtio_device *vdev, unsigned offset,
141 		   void *buf, unsigned len)
142 {
143 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
144 	u8 b;
145 	__le16 w;
146 	__le32 l;
147 
148 	BUG_ON(offset + len > vp_dev->device_len);
149 
150 	switch (len) {
151 	case 1:
152 		b = ioread8(vp_dev->device + offset);
153 		memcpy(buf, &b, sizeof b);
154 		break;
155 	case 2:
156 		w = cpu_to_le16(ioread16(vp_dev->device + offset));
157 		memcpy(buf, &w, sizeof w);
158 		break;
159 	case 4:
160 		l = cpu_to_le32(ioread32(vp_dev->device + offset));
161 		memcpy(buf, &l, sizeof l);
162 		break;
163 	case 8:
164 		l = cpu_to_le32(ioread32(vp_dev->device + offset));
165 		memcpy(buf, &l, sizeof l);
166 		l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
167 		memcpy(buf + sizeof l, &l, sizeof l);
168 		break;
169 	default:
170 		BUG();
171 	}
172 }
173 
174 /* the config->set() implementation.  it's symmetric to the config->get()
175  * implementation */
176 static void vp_set(struct virtio_device *vdev, unsigned offset,
177 		   const void *buf, unsigned len)
178 {
179 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
180 	u8 b;
181 	__le16 w;
182 	__le32 l;
183 
184 	BUG_ON(offset + len > vp_dev->device_len);
185 
186 	switch (len) {
187 	case 1:
188 		memcpy(&b, buf, sizeof b);
189 		iowrite8(b, vp_dev->device + offset);
190 		break;
191 	case 2:
192 		memcpy(&w, buf, sizeof w);
193 		iowrite16(le16_to_cpu(w), vp_dev->device + offset);
194 		break;
195 	case 4:
196 		memcpy(&l, buf, sizeof l);
197 		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
198 		break;
199 	case 8:
200 		memcpy(&l, buf, sizeof l);
201 		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
202 		memcpy(&l, buf + sizeof l, sizeof l);
203 		iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
204 		break;
205 	default:
206 		BUG();
207 	}
208 }
209 
210 static u32 vp_generation(struct virtio_device *vdev)
211 {
212 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
213 	return ioread8(&vp_dev->common->config_generation);
214 }
215 
216 /* config->{get,set}_status() implementations */
217 static u8 vp_get_status(struct virtio_device *vdev)
218 {
219 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
220 	return ioread8(&vp_dev->common->device_status);
221 }
222 
223 static void vp_set_status(struct virtio_device *vdev, u8 status)
224 {
225 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
226 	/* We should never be setting status to 0. */
227 	BUG_ON(status == 0);
228 	iowrite8(status, &vp_dev->common->device_status);
229 }
230 
231 static void vp_reset(struct virtio_device *vdev)
232 {
233 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
234 	/* 0 status means a reset. */
235 	iowrite8(0, &vp_dev->common->device_status);
236 	/* Flush out the status write, and flush in device writes,
237 	 * including MSI-X interrupts, if any. */
238 	ioread8(&vp_dev->common->device_status);
239 	/* Flush pending VQ/configuration callbacks. */
240 	vp_synchronize_vectors(vdev);
241 }
242 
243 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
244 {
245 	/* Setup the vector used for configuration events */
246 	iowrite16(vector, &vp_dev->common->msix_config);
247 	/* Verify we had enough resources to assign the vector */
248 	/* Will also flush the write out to device */
249 	return ioread16(&vp_dev->common->msix_config);
250 }
251 
252 static size_t vring_pci_size(u16 num)
253 {
254 	/* We only need a cacheline separation. */
255 	return PAGE_ALIGN(vring_size(num, SMP_CACHE_BYTES));
256 }
257 
258 static void *alloc_virtqueue_pages(int *num)
259 {
260 	void *pages;
261 
262 	/* TODO: allocate each queue chunk individually */
263 	for (; *num && vring_pci_size(*num) > PAGE_SIZE; *num /= 2) {
264 		pages = alloc_pages_exact(vring_pci_size(*num),
265 					  GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
266 		if (pages)
267 			return pages;
268 	}
269 
270 	if (!*num)
271 		return NULL;
272 
273 	/* Try to get a single page. You are my only hope! */
274 	return alloc_pages_exact(vring_pci_size(*num), GFP_KERNEL|__GFP_ZERO);
275 }
276 
277 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
278 				  struct virtio_pci_vq_info *info,
279 				  unsigned index,
280 				  void (*callback)(struct virtqueue *vq),
281 				  const char *name,
282 				  u16 msix_vec)
283 {
284 	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
285 	struct virtqueue *vq;
286 	u16 num, off;
287 	int err;
288 
289 	if (index >= ioread16(&cfg->num_queues))
290 		return ERR_PTR(-ENOENT);
291 
292 	/* Select the queue we're interested in */
293 	iowrite16(index, &cfg->queue_select);
294 
295 	/* Check if queue is either not available or already active. */
296 	num = ioread16(&cfg->queue_size);
297 	if (!num || ioread16(&cfg->queue_enable))
298 		return ERR_PTR(-ENOENT);
299 
300 	if (num & (num - 1)) {
301 		dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
302 		return ERR_PTR(-EINVAL);
303 	}
304 
305 	/* get offset of notification word for this vq */
306 	off = ioread16(&cfg->queue_notify_off);
307 
308 	info->num = num;
309 	info->msix_vector = msix_vec;
310 
311 	info->queue = alloc_virtqueue_pages(&info->num);
312 	if (info->queue == NULL)
313 		return ERR_PTR(-ENOMEM);
314 
315 	/* create the vring */
316 	vq = vring_new_virtqueue(index, info->num,
317 				 SMP_CACHE_BYTES, &vp_dev->vdev,
318 				 true, info->queue, vp_notify, callback, name);
319 	if (!vq) {
320 		err = -ENOMEM;
321 		goto err_new_queue;
322 	}
323 
324 	/* activate the queue */
325 	iowrite16(num, &cfg->queue_size);
326 	iowrite64_twopart(virt_to_phys(info->queue),
327 			  &cfg->queue_desc_lo, &cfg->queue_desc_hi);
328 	iowrite64_twopart(virt_to_phys(virtqueue_get_avail(vq)),
329 			  &cfg->queue_avail_lo, &cfg->queue_avail_hi);
330 	iowrite64_twopart(virt_to_phys(virtqueue_get_used(vq)),
331 			  &cfg->queue_used_lo, &cfg->queue_used_hi);
332 
333 	if (vp_dev->notify_base) {
334 		/* offset should not wrap */
335 		if ((u64)off * vp_dev->notify_offset_multiplier + 2
336 		    > vp_dev->notify_len) {
337 			dev_warn(&vp_dev->pci_dev->dev,
338 				 "bad notification offset %u (x %u) "
339 				 "for queue %u > %zd",
340 				 off, vp_dev->notify_offset_multiplier,
341 				 index, vp_dev->notify_len);
342 			err = -EINVAL;
343 			goto err_map_notify;
344 		}
345 		vq->priv = (void __force *)vp_dev->notify_base +
346 			off * vp_dev->notify_offset_multiplier;
347 	} else {
348 		vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
349 					  vp_dev->notify_map_cap, 2, 2,
350 					  off * vp_dev->notify_offset_multiplier, 2,
351 					  NULL);
352 	}
353 
354 	if (!vq->priv) {
355 		err = -ENOMEM;
356 		goto err_map_notify;
357 	}
358 
359 	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
360 		iowrite16(msix_vec, &cfg->queue_msix_vector);
361 		msix_vec = ioread16(&cfg->queue_msix_vector);
362 		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
363 			err = -EBUSY;
364 			goto err_assign_vector;
365 		}
366 	}
367 
368 	return vq;
369 
370 err_assign_vector:
371 	if (!vp_dev->notify_base)
372 		pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
373 err_map_notify:
374 	vring_del_virtqueue(vq);
375 err_new_queue:
376 	free_pages_exact(info->queue, vring_pci_size(info->num));
377 	return ERR_PTR(err);
378 }
379 
380 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
381 			      struct virtqueue *vqs[],
382 			      vq_callback_t *callbacks[],
383 			      const char *names[])
384 {
385 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
386 	struct virtqueue *vq;
387 	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);
388 
389 	if (rc)
390 		return rc;
391 
392 	/* Select and activate all queues. Has to be done last: once we do
393 	 * this, there's no way to go back except reset.
394 	 */
395 	list_for_each_entry(vq, &vdev->vqs, list) {
396 		iowrite16(vq->index, &vp_dev->common->queue_select);
397 		iowrite16(1, &vp_dev->common->queue_enable);
398 	}
399 
400 	return 0;
401 }
402 
403 static void del_vq(struct virtio_pci_vq_info *info)
404 {
405 	struct virtqueue *vq = info->vq;
406 	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
407 
408 	iowrite16(vq->index, &vp_dev->common->queue_select);
409 
410 	if (vp_dev->msix_enabled) {
411 		iowrite16(VIRTIO_MSI_NO_VECTOR,
412 			  &vp_dev->common->queue_msix_vector);
413 		/* Flush the write out to device */
414 		ioread16(&vp_dev->common->queue_msix_vector);
415 	}
416 
417 	if (!vp_dev->notify_base)
418 		pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
419 
420 	vring_del_virtqueue(vq);
421 
422 	free_pages_exact(info->queue, vring_pci_size(info->num));
423 }
424 
425 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
426 	.get		= NULL,
427 	.set		= NULL,
428 	.generation	= vp_generation,
429 	.get_status	= vp_get_status,
430 	.set_status	= vp_set_status,
431 	.reset		= vp_reset,
432 	.find_vqs	= vp_modern_find_vqs,
433 	.del_vqs	= vp_del_vqs,
434 	.get_features	= vp_get_features,
435 	.finalize_features = vp_finalize_features,
436 	.bus_name	= vp_bus_name,
437 	.set_vq_affinity = vp_set_vq_affinity,
438 };
439 
440 static const struct virtio_config_ops virtio_pci_config_ops = {
441 	.get		= vp_get,
442 	.set		= vp_set,
443 	.generation	= vp_generation,
444 	.get_status	= vp_get_status,
445 	.set_status	= vp_set_status,
446 	.reset		= vp_reset,
447 	.find_vqs	= vp_modern_find_vqs,
448 	.del_vqs	= vp_del_vqs,
449 	.get_features	= vp_get_features,
450 	.finalize_features = vp_finalize_features,
451 	.bus_name	= vp_bus_name,
452 	.set_vq_affinity = vp_set_vq_affinity,
453 };
454 
455 /**
456  * virtio_pci_find_capability - walk capabilities to find device info.
457  * @dev: the pci device
458  * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
459  * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
460  *
461  * Returns offset of the capability, or 0.
462  */
463 static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
464 					     u32 ioresource_types)
465 {
466 	int pos;
467 
468 	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
469 	     pos > 0;
470 	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
471 		u8 type, bar;
472 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
473 							 cfg_type),
474 				     &type);
475 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
476 							 bar),
477 				     &bar);
478 
479 		/* Ignore structures with reserved BAR values */
480 		if (bar > 0x5)
481 			continue;
482 
483 		if (type == cfg_type) {
484 			if (pci_resource_len(dev, bar) &&
485 			    pci_resource_flags(dev, bar) & ioresource_types)
486 				return pos;
487 		}
488 	}
489 	return 0;
490 }
491 
492 /* This is part of the ABI.  Don't screw with it. */
493 static inline void check_offsets(void)
494 {
495 	/* Note: disk space was harmed in compilation of this function. */
496 	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
497 		     offsetof(struct virtio_pci_cap, cap_vndr));
498 	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
499 		     offsetof(struct virtio_pci_cap, cap_next));
500 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
501 		     offsetof(struct virtio_pci_cap, cap_len));
502 	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
503 		     offsetof(struct virtio_pci_cap, cfg_type));
504 	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
505 		     offsetof(struct virtio_pci_cap, bar));
506 	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
507 		     offsetof(struct virtio_pci_cap, offset));
508 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
509 		     offsetof(struct virtio_pci_cap, length));
510 	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
511 		     offsetof(struct virtio_pci_notify_cap,
512 			      notify_off_multiplier));
513 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
514 		     offsetof(struct virtio_pci_common_cfg,
515 			      device_feature_select));
516 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
517 		     offsetof(struct virtio_pci_common_cfg, device_feature));
518 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
519 		     offsetof(struct virtio_pci_common_cfg,
520 			      guest_feature_select));
521 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
522 		     offsetof(struct virtio_pci_common_cfg, guest_feature));
523 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
524 		     offsetof(struct virtio_pci_common_cfg, msix_config));
525 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
526 		     offsetof(struct virtio_pci_common_cfg, num_queues));
527 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
528 		     offsetof(struct virtio_pci_common_cfg, device_status));
529 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
530 		     offsetof(struct virtio_pci_common_cfg, config_generation));
531 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
532 		     offsetof(struct virtio_pci_common_cfg, queue_select));
533 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
534 		     offsetof(struct virtio_pci_common_cfg, queue_size));
535 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
536 		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
537 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
538 		     offsetof(struct virtio_pci_common_cfg, queue_enable));
539 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
540 		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
541 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
542 		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
543 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
544 		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
545 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
546 		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
547 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
548 		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
549 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
550 		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
551 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
552 		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
553 }
554 
555 /* the PCI probing function */
556 int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
557 {
558 	struct pci_dev *pci_dev = vp_dev->pci_dev;
559 	int err, common, isr, notify, device;
560 	u32 notify_length;
561 	u32 notify_offset;
562 
563 	check_offsets();
564 
565 	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
566 	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
567 		return -ENODEV;
568 
569 	if (pci_dev->device < 0x1040) {
570 		/* Transitional devices: use the PCI subsystem device id as
571 		 * virtio device id, same as legacy driver always did.
572 		 */
573 		vp_dev->vdev.id.device = pci_dev->subsystem_device;
574 	} else {
575 		/* Modern devices: simply use PCI device id, but start from 0x1040. */
576 		vp_dev->vdev.id.device = pci_dev->device - 0x1040;
577 	}
578 	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
579 
580 	if (virtio_device_is_legacy_only(vp_dev->vdev.id))
581 		return -ENODEV;
582 
583 	/* check for a common config: if not, use legacy mode (bar 0). */
584 	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
585 					    IORESOURCE_IO | IORESOURCE_MEM);
586 	if (!common) {
587 		dev_info(&pci_dev->dev,
588 			 "virtio_pci: leaving for legacy driver\n");
589 		return -ENODEV;
590 	}
591 
592 	/* If common is there, these should be too... */
593 	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
594 					 IORESOURCE_IO | IORESOURCE_MEM);
595 	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
596 					    IORESOURCE_IO | IORESOURCE_MEM);
597 	if (!isr || !notify) {
598 		dev_err(&pci_dev->dev,
599 			"virtio_pci: missing capabilities %i/%i/%i\n",
600 			common, isr, notify);
601 		return -EINVAL;
602 	}
603 
604 	/* Device capability is only mandatory for devices that have
605 	 * device-specific configuration.
606 	 */
607 	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
608 					    IORESOURCE_IO | IORESOURCE_MEM);
609 
610 	err = -EINVAL;
611 	vp_dev->common = map_capability(pci_dev, common,
612 					sizeof(struct virtio_pci_common_cfg), 4,
613 					0, sizeof(struct virtio_pci_common_cfg),
614 					NULL);
615 	if (!vp_dev->common)
616 		goto err_map_common;
617 	vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
618 				     0, 1,
619 				     NULL);
620 	if (!vp_dev->isr)
621 		goto err_map_isr;
622 
623 	/* Read notify_off_multiplier from config space. */
624 	pci_read_config_dword(pci_dev,
625 			      notify + offsetof(struct virtio_pci_notify_cap,
626 						notify_off_multiplier),
627 			      &vp_dev->notify_offset_multiplier);
628 	/* Read notify length and offset from config space. */
629 	pci_read_config_dword(pci_dev,
630 			      notify + offsetof(struct virtio_pci_notify_cap,
631 						cap.length),
632 			      &notify_length);
633 
634 	pci_read_config_dword(pci_dev,
635 			      notify + offsetof(struct virtio_pci_notify_cap,
636 						cap.length),
637 			      &notify_offset);
638 
639 	/* We don't know how many VQs we'll map, ahead of the time.
640 	 * If notify length is small, map it all now.
641 	 * Otherwise, map each VQ individually later.
642 	 */
643 	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
644 		vp_dev->notify_base = map_capability(pci_dev, notify, 2, 2,
645 						     0, notify_length,
646 						     &vp_dev->notify_len);
647 		if (!vp_dev->notify_base)
648 			goto err_map_notify;
649 	} else {
650 		vp_dev->notify_map_cap = notify;
651 	}
652 
653 	/* Again, we don't know how much we should map, but PAGE_SIZE
654 	 * is more than enough for all existing devices.
655 	 */
656 	if (device) {
657 		vp_dev->device = map_capability(pci_dev, device, 0, 4,
658 						0, PAGE_SIZE,
659 						&vp_dev->device_len);
660 		if (!vp_dev->device)
661 			goto err_map_device;
662 
663 		vp_dev->vdev.config = &virtio_pci_config_ops;
664 	} else {
665 		vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
666 	}
667 
668 	vp_dev->config_vector = vp_config_vector;
669 	vp_dev->setup_vq = setup_vq;
670 	vp_dev->del_vq = del_vq;
671 
672 	return 0;
673 
674 err_map_device:
675 	if (vp_dev->notify_base)
676 		pci_iounmap(pci_dev, vp_dev->notify_base);
677 err_map_notify:
678 	pci_iounmap(pci_dev, vp_dev->isr);
679 err_map_isr:
680 	pci_iounmap(pci_dev, vp_dev->common);
681 err_map_common:
682 	return err;
683 }
684 
685 void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
686 {
687 	struct pci_dev *pci_dev = vp_dev->pci_dev;
688 
689 	if (vp_dev->device)
690 		pci_iounmap(pci_dev, vp_dev->device);
691 	if (vp_dev->notify_base)
692 		pci_iounmap(pci_dev, vp_dev->notify_base);
693 	pci_iounmap(pci_dev, vp_dev->isr);
694 	pci_iounmap(pci_dev, vp_dev->common);
695 }
696