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 #include <linux/delay.h>
21 #define VIRTIO_PCI_NO_LEGACY
22 #include "virtio_pci_common.h"
23 
24 /*
25  * Type-safe wrappers for io accesses.
26  * Use these to enforce at compile time the following spec requirement:
27  *
28  * The driver MUST access each field using the “natural” access
29  * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
30  * for 16-bit fields and 8-bit accesses for 8-bit fields.
31  */
32 static inline u8 vp_ioread8(u8 __iomem *addr)
33 {
34 	return ioread8(addr);
35 }
36 static inline u16 vp_ioread16 (u16 __iomem *addr)
37 {
38 	return ioread16(addr);
39 }
40 
41 static inline u32 vp_ioread32(u32 __iomem *addr)
42 {
43 	return ioread32(addr);
44 }
45 
46 static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
47 {
48 	iowrite8(value, addr);
49 }
50 
51 static inline void vp_iowrite16(u16 value, u16 __iomem *addr)
52 {
53 	iowrite16(value, addr);
54 }
55 
56 static inline void vp_iowrite32(u32 value, u32 __iomem *addr)
57 {
58 	iowrite32(value, addr);
59 }
60 
61 static void vp_iowrite64_twopart(u64 val,
62 				 __le32 __iomem *lo, __le32 __iomem *hi)
63 {
64 	vp_iowrite32((u32)val, lo);
65 	vp_iowrite32(val >> 32, hi);
66 }
67 
68 static void __iomem *map_capability(struct pci_dev *dev, int off,
69 				    size_t minlen,
70 				    u32 align,
71 				    u32 start, u32 size,
72 				    size_t *len)
73 {
74 	u8 bar;
75 	u32 offset, length;
76 	void __iomem *p;
77 
78 	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
79 						 bar),
80 			     &bar);
81 	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
82 			     &offset);
83 	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
84 			      &length);
85 
86 	if (length <= start) {
87 		dev_err(&dev->dev,
88 			"virtio_pci: bad capability len %u (>%u expected)\n",
89 			length, start);
90 		return NULL;
91 	}
92 
93 	if (length - start < minlen) {
94 		dev_err(&dev->dev,
95 			"virtio_pci: bad capability len %u (>=%zu expected)\n",
96 			length, minlen);
97 		return NULL;
98 	}
99 
100 	length -= start;
101 
102 	if (start + offset < offset) {
103 		dev_err(&dev->dev,
104 			"virtio_pci: map wrap-around %u+%u\n",
105 			start, offset);
106 		return NULL;
107 	}
108 
109 	offset += start;
110 
111 	if (offset & (align - 1)) {
112 		dev_err(&dev->dev,
113 			"virtio_pci: offset %u not aligned to %u\n",
114 			offset, align);
115 		return NULL;
116 	}
117 
118 	if (length > size)
119 		length = size;
120 
121 	if (len)
122 		*len = length;
123 
124 	if (minlen + offset < minlen ||
125 	    minlen + offset > pci_resource_len(dev, bar)) {
126 		dev_err(&dev->dev,
127 			"virtio_pci: map virtio %zu@%u "
128 			"out of range on bar %i length %lu\n",
129 			minlen, offset,
130 			bar, (unsigned long)pci_resource_len(dev, bar));
131 		return NULL;
132 	}
133 
134 	p = pci_iomap_range(dev, bar, offset, length);
135 	if (!p)
136 		dev_err(&dev->dev,
137 			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
138 			length, offset, bar);
139 	return p;
140 }
141 
142 /* virtio config->get_features() implementation */
143 static u64 vp_get_features(struct virtio_device *vdev)
144 {
145 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
146 	u64 features;
147 
148 	vp_iowrite32(0, &vp_dev->common->device_feature_select);
149 	features = vp_ioread32(&vp_dev->common->device_feature);
150 	vp_iowrite32(1, &vp_dev->common->device_feature_select);
151 	features |= ((u64)vp_ioread32(&vp_dev->common->device_feature) << 32);
152 
153 	return features;
154 }
155 
156 /* virtio config->finalize_features() implementation */
157 static int vp_finalize_features(struct virtio_device *vdev)
158 {
159 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
160 
161 	/* Give virtio_ring a chance to accept features. */
162 	vring_transport_features(vdev);
163 
164 	if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
165 		dev_err(&vdev->dev, "virtio: device uses modern interface "
166 			"but does not have VIRTIO_F_VERSION_1\n");
167 		return -EINVAL;
168 	}
169 
170 	vp_iowrite32(0, &vp_dev->common->guest_feature_select);
171 	vp_iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
172 	vp_iowrite32(1, &vp_dev->common->guest_feature_select);
173 	vp_iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
174 
175 	return 0;
176 }
177 
178 /* virtio config->get() implementation */
179 static void vp_get(struct virtio_device *vdev, unsigned offset,
180 		   void *buf, unsigned len)
181 {
182 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
183 	u8 b;
184 	__le16 w;
185 	__le32 l;
186 
187 	BUG_ON(offset + len > vp_dev->device_len);
188 
189 	switch (len) {
190 	case 1:
191 		b = ioread8(vp_dev->device + offset);
192 		memcpy(buf, &b, sizeof b);
193 		break;
194 	case 2:
195 		w = cpu_to_le16(ioread16(vp_dev->device + offset));
196 		memcpy(buf, &w, sizeof w);
197 		break;
198 	case 4:
199 		l = cpu_to_le32(ioread32(vp_dev->device + offset));
200 		memcpy(buf, &l, sizeof l);
201 		break;
202 	case 8:
203 		l = cpu_to_le32(ioread32(vp_dev->device + offset));
204 		memcpy(buf, &l, sizeof l);
205 		l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
206 		memcpy(buf + sizeof l, &l, sizeof l);
207 		break;
208 	default:
209 		BUG();
210 	}
211 }
212 
213 /* the config->set() implementation.  it's symmetric to the config->get()
214  * implementation */
215 static void vp_set(struct virtio_device *vdev, unsigned offset,
216 		   const void *buf, unsigned len)
217 {
218 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
219 	u8 b;
220 	__le16 w;
221 	__le32 l;
222 
223 	BUG_ON(offset + len > vp_dev->device_len);
224 
225 	switch (len) {
226 	case 1:
227 		memcpy(&b, buf, sizeof b);
228 		iowrite8(b, vp_dev->device + offset);
229 		break;
230 	case 2:
231 		memcpy(&w, buf, sizeof w);
232 		iowrite16(le16_to_cpu(w), vp_dev->device + offset);
233 		break;
234 	case 4:
235 		memcpy(&l, buf, sizeof l);
236 		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
237 		break;
238 	case 8:
239 		memcpy(&l, buf, sizeof l);
240 		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
241 		memcpy(&l, buf + sizeof l, sizeof l);
242 		iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
243 		break;
244 	default:
245 		BUG();
246 	}
247 }
248 
249 static u32 vp_generation(struct virtio_device *vdev)
250 {
251 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
252 	return vp_ioread8(&vp_dev->common->config_generation);
253 }
254 
255 /* config->{get,set}_status() implementations */
256 static u8 vp_get_status(struct virtio_device *vdev)
257 {
258 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
259 	return vp_ioread8(&vp_dev->common->device_status);
260 }
261 
262 static void vp_set_status(struct virtio_device *vdev, u8 status)
263 {
264 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
265 	/* We should never be setting status to 0. */
266 	BUG_ON(status == 0);
267 	vp_iowrite8(status, &vp_dev->common->device_status);
268 }
269 
270 static void vp_reset(struct virtio_device *vdev)
271 {
272 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
273 	/* 0 status means a reset. */
274 	vp_iowrite8(0, &vp_dev->common->device_status);
275 	/* After writing 0 to device_status, the driver MUST wait for a read of
276 	 * device_status to return 0 before reinitializing the device.
277 	 * This will flush out the status write, and flush in device writes,
278 	 * including MSI-X interrupts, if any.
279 	 */
280 	while (vp_ioread8(&vp_dev->common->device_status))
281 		msleep(1);
282 	/* Flush pending VQ/configuration callbacks. */
283 	vp_synchronize_vectors(vdev);
284 }
285 
286 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
287 {
288 	/* Setup the vector used for configuration events */
289 	vp_iowrite16(vector, &vp_dev->common->msix_config);
290 	/* Verify we had enough resources to assign the vector */
291 	/* Will also flush the write out to device */
292 	return vp_ioread16(&vp_dev->common->msix_config);
293 }
294 
295 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
296 				  struct virtio_pci_vq_info *info,
297 				  unsigned index,
298 				  void (*callback)(struct virtqueue *vq),
299 				  const char *name,
300 				  u16 msix_vec)
301 {
302 	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
303 	struct virtqueue *vq;
304 	u16 num, off;
305 	int err;
306 
307 	if (index >= vp_ioread16(&cfg->num_queues))
308 		return ERR_PTR(-ENOENT);
309 
310 	/* Select the queue we're interested in */
311 	vp_iowrite16(index, &cfg->queue_select);
312 
313 	/* Check if queue is either not available or already active. */
314 	num = vp_ioread16(&cfg->queue_size);
315 	if (!num || vp_ioread16(&cfg->queue_enable))
316 		return ERR_PTR(-ENOENT);
317 
318 	if (num & (num - 1)) {
319 		dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
320 		return ERR_PTR(-EINVAL);
321 	}
322 
323 	/* get offset of notification word for this vq */
324 	off = vp_ioread16(&cfg->queue_notify_off);
325 
326 	info->msix_vector = msix_vec;
327 
328 	/* create the vring */
329 	vq = vring_create_virtqueue(index, num,
330 				    SMP_CACHE_BYTES, &vp_dev->vdev,
331 				    true, true, vp_notify, callback, name);
332 	if (!vq)
333 		return ERR_PTR(-ENOMEM);
334 
335 	/* activate the queue */
336 	vp_iowrite16(virtqueue_get_vring_size(vq), &cfg->queue_size);
337 	vp_iowrite64_twopart(virtqueue_get_desc_addr(vq),
338 			     &cfg->queue_desc_lo, &cfg->queue_desc_hi);
339 	vp_iowrite64_twopart(virtqueue_get_avail_addr(vq),
340 			     &cfg->queue_avail_lo, &cfg->queue_avail_hi);
341 	vp_iowrite64_twopart(virtqueue_get_used_addr(vq),
342 			     &cfg->queue_used_lo, &cfg->queue_used_hi);
343 
344 	if (vp_dev->notify_base) {
345 		/* offset should not wrap */
346 		if ((u64)off * vp_dev->notify_offset_multiplier + 2
347 		    > vp_dev->notify_len) {
348 			dev_warn(&vp_dev->pci_dev->dev,
349 				 "bad notification offset %u (x %u) "
350 				 "for queue %u > %zd",
351 				 off, vp_dev->notify_offset_multiplier,
352 				 index, vp_dev->notify_len);
353 			err = -EINVAL;
354 			goto err_map_notify;
355 		}
356 		vq->priv = (void __force *)vp_dev->notify_base +
357 			off * vp_dev->notify_offset_multiplier;
358 	} else {
359 		vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
360 					  vp_dev->notify_map_cap, 2, 2,
361 					  off * vp_dev->notify_offset_multiplier, 2,
362 					  NULL);
363 	}
364 
365 	if (!vq->priv) {
366 		err = -ENOMEM;
367 		goto err_map_notify;
368 	}
369 
370 	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
371 		vp_iowrite16(msix_vec, &cfg->queue_msix_vector);
372 		msix_vec = vp_ioread16(&cfg->queue_msix_vector);
373 		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
374 			err = -EBUSY;
375 			goto err_assign_vector;
376 		}
377 	}
378 
379 	return vq;
380 
381 err_assign_vector:
382 	if (!vp_dev->notify_base)
383 		pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
384 err_map_notify:
385 	vring_del_virtqueue(vq);
386 	return ERR_PTR(err);
387 }
388 
389 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
390 			      struct virtqueue *vqs[],
391 			      vq_callback_t *callbacks[],
392 			      const char * const names[])
393 {
394 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
395 	struct virtqueue *vq;
396 	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);
397 
398 	if (rc)
399 		return rc;
400 
401 	/* Select and activate all queues. Has to be done last: once we do
402 	 * this, there's no way to go back except reset.
403 	 */
404 	list_for_each_entry(vq, &vdev->vqs, list) {
405 		vp_iowrite16(vq->index, &vp_dev->common->queue_select);
406 		vp_iowrite16(1, &vp_dev->common->queue_enable);
407 	}
408 
409 	return 0;
410 }
411 
412 static void del_vq(struct virtio_pci_vq_info *info)
413 {
414 	struct virtqueue *vq = info->vq;
415 	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
416 
417 	vp_iowrite16(vq->index, &vp_dev->common->queue_select);
418 
419 	if (vp_dev->msix_enabled) {
420 		vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
421 			     &vp_dev->common->queue_msix_vector);
422 		/* Flush the write out to device */
423 		vp_ioread16(&vp_dev->common->queue_msix_vector);
424 	}
425 
426 	if (!vp_dev->notify_base)
427 		pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
428 
429 	vring_del_virtqueue(vq);
430 }
431 
432 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
433 	.get		= NULL,
434 	.set		= NULL,
435 	.generation	= vp_generation,
436 	.get_status	= vp_get_status,
437 	.set_status	= vp_set_status,
438 	.reset		= vp_reset,
439 	.find_vqs	= vp_modern_find_vqs,
440 	.del_vqs	= vp_del_vqs,
441 	.get_features	= vp_get_features,
442 	.finalize_features = vp_finalize_features,
443 	.bus_name	= vp_bus_name,
444 	.set_vq_affinity = vp_set_vq_affinity,
445 };
446 
447 static const struct virtio_config_ops virtio_pci_config_ops = {
448 	.get		= vp_get,
449 	.set		= vp_set,
450 	.generation	= vp_generation,
451 	.get_status	= vp_get_status,
452 	.set_status	= vp_set_status,
453 	.reset		= vp_reset,
454 	.find_vqs	= vp_modern_find_vqs,
455 	.del_vqs	= vp_del_vqs,
456 	.get_features	= vp_get_features,
457 	.finalize_features = vp_finalize_features,
458 	.bus_name	= vp_bus_name,
459 	.set_vq_affinity = vp_set_vq_affinity,
460 };
461 
462 /**
463  * virtio_pci_find_capability - walk capabilities to find device info.
464  * @dev: the pci device
465  * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
466  * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
467  *
468  * Returns offset of the capability, or 0.
469  */
470 static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
471 					     u32 ioresource_types, int *bars)
472 {
473 	int pos;
474 
475 	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
476 	     pos > 0;
477 	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
478 		u8 type, bar;
479 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
480 							 cfg_type),
481 				     &type);
482 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
483 							 bar),
484 				     &bar);
485 
486 		/* Ignore structures with reserved BAR values */
487 		if (bar > 0x5)
488 			continue;
489 
490 		if (type == cfg_type) {
491 			if (pci_resource_len(dev, bar) &&
492 			    pci_resource_flags(dev, bar) & ioresource_types) {
493 				*bars |= (1 << bar);
494 				return pos;
495 			}
496 		}
497 	}
498 	return 0;
499 }
500 
501 /* This is part of the ABI.  Don't screw with it. */
502 static inline void check_offsets(void)
503 {
504 	/* Note: disk space was harmed in compilation of this function. */
505 	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
506 		     offsetof(struct virtio_pci_cap, cap_vndr));
507 	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
508 		     offsetof(struct virtio_pci_cap, cap_next));
509 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
510 		     offsetof(struct virtio_pci_cap, cap_len));
511 	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
512 		     offsetof(struct virtio_pci_cap, cfg_type));
513 	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
514 		     offsetof(struct virtio_pci_cap, bar));
515 	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
516 		     offsetof(struct virtio_pci_cap, offset));
517 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
518 		     offsetof(struct virtio_pci_cap, length));
519 	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
520 		     offsetof(struct virtio_pci_notify_cap,
521 			      notify_off_multiplier));
522 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
523 		     offsetof(struct virtio_pci_common_cfg,
524 			      device_feature_select));
525 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
526 		     offsetof(struct virtio_pci_common_cfg, device_feature));
527 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
528 		     offsetof(struct virtio_pci_common_cfg,
529 			      guest_feature_select));
530 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
531 		     offsetof(struct virtio_pci_common_cfg, guest_feature));
532 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
533 		     offsetof(struct virtio_pci_common_cfg, msix_config));
534 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
535 		     offsetof(struct virtio_pci_common_cfg, num_queues));
536 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
537 		     offsetof(struct virtio_pci_common_cfg, device_status));
538 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
539 		     offsetof(struct virtio_pci_common_cfg, config_generation));
540 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
541 		     offsetof(struct virtio_pci_common_cfg, queue_select));
542 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
543 		     offsetof(struct virtio_pci_common_cfg, queue_size));
544 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
545 		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
546 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
547 		     offsetof(struct virtio_pci_common_cfg, queue_enable));
548 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
549 		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
550 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
551 		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
552 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
553 		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
554 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
555 		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
556 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
557 		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
558 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
559 		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
560 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
561 		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
562 }
563 
564 /* the PCI probing function */
565 int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
566 {
567 	struct pci_dev *pci_dev = vp_dev->pci_dev;
568 	int err, common, isr, notify, device;
569 	u32 notify_length;
570 	u32 notify_offset;
571 
572 	check_offsets();
573 
574 	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
575 	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
576 		return -ENODEV;
577 
578 	if (pci_dev->device < 0x1040) {
579 		/* Transitional devices: use the PCI subsystem device id as
580 		 * virtio device id, same as legacy driver always did.
581 		 */
582 		vp_dev->vdev.id.device = pci_dev->subsystem_device;
583 	} else {
584 		/* Modern devices: simply use PCI device id, but start from 0x1040. */
585 		vp_dev->vdev.id.device = pci_dev->device - 0x1040;
586 	}
587 	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
588 
589 	/* check for a common config: if not, use legacy mode (bar 0). */
590 	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
591 					    IORESOURCE_IO | IORESOURCE_MEM,
592 					    &vp_dev->modern_bars);
593 	if (!common) {
594 		dev_info(&pci_dev->dev,
595 			 "virtio_pci: leaving for legacy driver\n");
596 		return -ENODEV;
597 	}
598 
599 	/* If common is there, these should be too... */
600 	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
601 					 IORESOURCE_IO | IORESOURCE_MEM,
602 					 &vp_dev->modern_bars);
603 	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
604 					    IORESOURCE_IO | IORESOURCE_MEM,
605 					    &vp_dev->modern_bars);
606 	if (!isr || !notify) {
607 		dev_err(&pci_dev->dev,
608 			"virtio_pci: missing capabilities %i/%i/%i\n",
609 			common, isr, notify);
610 		return -EINVAL;
611 	}
612 
613 	err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
614 	if (err)
615 		err = dma_set_mask_and_coherent(&pci_dev->dev,
616 						DMA_BIT_MASK(32));
617 	if (err)
618 		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
619 
620 	/* Device capability is only mandatory for devices that have
621 	 * device-specific configuration.
622 	 */
623 	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
624 					    IORESOURCE_IO | IORESOURCE_MEM,
625 					    &vp_dev->modern_bars);
626 
627 	err = pci_request_selected_regions(pci_dev, vp_dev->modern_bars,
628 					   "virtio-pci-modern");
629 	if (err)
630 		return err;
631 
632 	err = -EINVAL;
633 	vp_dev->common = map_capability(pci_dev, common,
634 					sizeof(struct virtio_pci_common_cfg), 4,
635 					0, sizeof(struct virtio_pci_common_cfg),
636 					NULL);
637 	if (!vp_dev->common)
638 		goto err_map_common;
639 	vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
640 				     0, 1,
641 				     NULL);
642 	if (!vp_dev->isr)
643 		goto err_map_isr;
644 
645 	/* Read notify_off_multiplier from config space. */
646 	pci_read_config_dword(pci_dev,
647 			      notify + offsetof(struct virtio_pci_notify_cap,
648 						notify_off_multiplier),
649 			      &vp_dev->notify_offset_multiplier);
650 	/* Read notify length and offset from config space. */
651 	pci_read_config_dword(pci_dev,
652 			      notify + offsetof(struct virtio_pci_notify_cap,
653 						cap.length),
654 			      &notify_length);
655 
656 	pci_read_config_dword(pci_dev,
657 			      notify + offsetof(struct virtio_pci_notify_cap,
658 						cap.offset),
659 			      &notify_offset);
660 
661 	/* We don't know how many VQs we'll map, ahead of the time.
662 	 * If notify length is small, map it all now.
663 	 * Otherwise, map each VQ individually later.
664 	 */
665 	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
666 		vp_dev->notify_base = map_capability(pci_dev, notify, 2, 2,
667 						     0, notify_length,
668 						     &vp_dev->notify_len);
669 		if (!vp_dev->notify_base)
670 			goto err_map_notify;
671 	} else {
672 		vp_dev->notify_map_cap = notify;
673 	}
674 
675 	/* Again, we don't know how much we should map, but PAGE_SIZE
676 	 * is more than enough for all existing devices.
677 	 */
678 	if (device) {
679 		vp_dev->device = map_capability(pci_dev, device, 0, 4,
680 						0, PAGE_SIZE,
681 						&vp_dev->device_len);
682 		if (!vp_dev->device)
683 			goto err_map_device;
684 
685 		vp_dev->vdev.config = &virtio_pci_config_ops;
686 	} else {
687 		vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
688 	}
689 
690 	vp_dev->config_vector = vp_config_vector;
691 	vp_dev->setup_vq = setup_vq;
692 	vp_dev->del_vq = del_vq;
693 
694 	return 0;
695 
696 err_map_device:
697 	if (vp_dev->notify_base)
698 		pci_iounmap(pci_dev, vp_dev->notify_base);
699 err_map_notify:
700 	pci_iounmap(pci_dev, vp_dev->isr);
701 err_map_isr:
702 	pci_iounmap(pci_dev, vp_dev->common);
703 err_map_common:
704 	return err;
705 }
706 
707 void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
708 {
709 	struct pci_dev *pci_dev = vp_dev->pci_dev;
710 
711 	if (vp_dev->device)
712 		pci_iounmap(pci_dev, vp_dev->device);
713 	if (vp_dev->notify_base)
714 		pci_iounmap(pci_dev, vp_dev->notify_base);
715 	pci_iounmap(pci_dev, vp_dev->isr);
716 	pci_iounmap(pci_dev, vp_dev->common);
717 	pci_release_selected_regions(pci_dev, vp_dev->modern_bars);
718 }
719