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  */
vp_ioread8(u8 __iomem * addr)32 static inline u8 vp_ioread8(u8 __iomem *addr)
33 {
34 	return ioread8(addr);
35 }
vp_ioread16(__le16 __iomem * addr)36 static inline u16 vp_ioread16 (__le16 __iomem *addr)
37 {
38 	return ioread16(addr);
39 }
40 
vp_ioread32(__le32 __iomem * addr)41 static inline u32 vp_ioread32(__le32 __iomem *addr)
42 {
43 	return ioread32(addr);
44 }
45 
vp_iowrite8(u8 value,u8 __iomem * addr)46 static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
47 {
48 	iowrite8(value, addr);
49 }
50 
vp_iowrite16(u16 value,__le16 __iomem * addr)51 static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
52 {
53 	iowrite16(value, addr);
54 }
55 
vp_iowrite32(u32 value,__le32 __iomem * addr)56 static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
57 {
58 	iowrite32(value, addr);
59 }
60 
vp_iowrite64_twopart(u64 val,__le32 __iomem * lo,__le32 __iomem * hi)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 
map_capability(struct pci_dev * dev,int off,size_t minlen,u32 align,u32 start,u32 size,size_t * len)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 */
vp_get_features(struct virtio_device * vdev)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 
vp_transport_features(struct virtio_device * vdev,u64 features)156 static void vp_transport_features(struct virtio_device *vdev, u64 features)
157 {
158 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
159 	struct pci_dev *pci_dev = vp_dev->pci_dev;
160 
161 	if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
162 			pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
163 		__virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
164 }
165 
166 /* virtio config->finalize_features() implementation */
vp_finalize_features(struct virtio_device * vdev)167 static int vp_finalize_features(struct virtio_device *vdev)
168 {
169 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
170 	u64 features = vdev->features;
171 
172 	/* Give virtio_ring a chance to accept features. */
173 	vring_transport_features(vdev);
174 
175 	/* Give virtio_pci a chance to accept features. */
176 	vp_transport_features(vdev, features);
177 
178 	if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
179 		dev_err(&vdev->dev, "virtio: device uses modern interface "
180 			"but does not have VIRTIO_F_VERSION_1\n");
181 		return -EINVAL;
182 	}
183 
184 	vp_iowrite32(0, &vp_dev->common->guest_feature_select);
185 	vp_iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
186 	vp_iowrite32(1, &vp_dev->common->guest_feature_select);
187 	vp_iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
188 
189 	return 0;
190 }
191 
192 /* virtio config->get() implementation */
vp_get(struct virtio_device * vdev,unsigned offset,void * buf,unsigned len)193 static void vp_get(struct virtio_device *vdev, unsigned offset,
194 		   void *buf, unsigned len)
195 {
196 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
197 	u8 b;
198 	__le16 w;
199 	__le32 l;
200 
201 	BUG_ON(offset + len > vp_dev->device_len);
202 
203 	switch (len) {
204 	case 1:
205 		b = ioread8(vp_dev->device + offset);
206 		memcpy(buf, &b, sizeof b);
207 		break;
208 	case 2:
209 		w = cpu_to_le16(ioread16(vp_dev->device + offset));
210 		memcpy(buf, &w, sizeof w);
211 		break;
212 	case 4:
213 		l = cpu_to_le32(ioread32(vp_dev->device + offset));
214 		memcpy(buf, &l, sizeof l);
215 		break;
216 	case 8:
217 		l = cpu_to_le32(ioread32(vp_dev->device + offset));
218 		memcpy(buf, &l, sizeof l);
219 		l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
220 		memcpy(buf + sizeof l, &l, sizeof l);
221 		break;
222 	default:
223 		BUG();
224 	}
225 }
226 
227 /* the config->set() implementation.  it's symmetric to the config->get()
228  * implementation */
vp_set(struct virtio_device * vdev,unsigned offset,const void * buf,unsigned len)229 static void vp_set(struct virtio_device *vdev, unsigned offset,
230 		   const void *buf, unsigned len)
231 {
232 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
233 	u8 b;
234 	__le16 w;
235 	__le32 l;
236 
237 	BUG_ON(offset + len > vp_dev->device_len);
238 
239 	switch (len) {
240 	case 1:
241 		memcpy(&b, buf, sizeof b);
242 		iowrite8(b, vp_dev->device + offset);
243 		break;
244 	case 2:
245 		memcpy(&w, buf, sizeof w);
246 		iowrite16(le16_to_cpu(w), vp_dev->device + offset);
247 		break;
248 	case 4:
249 		memcpy(&l, buf, sizeof l);
250 		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
251 		break;
252 	case 8:
253 		memcpy(&l, buf, sizeof l);
254 		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
255 		memcpy(&l, buf + sizeof l, sizeof l);
256 		iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
257 		break;
258 	default:
259 		BUG();
260 	}
261 }
262 
vp_generation(struct virtio_device * vdev)263 static u32 vp_generation(struct virtio_device *vdev)
264 {
265 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
266 	return vp_ioread8(&vp_dev->common->config_generation);
267 }
268 
269 /* config->{get,set}_status() implementations */
vp_get_status(struct virtio_device * vdev)270 static u8 vp_get_status(struct virtio_device *vdev)
271 {
272 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
273 	return vp_ioread8(&vp_dev->common->device_status);
274 }
275 
vp_set_status(struct virtio_device * vdev,u8 status)276 static void vp_set_status(struct virtio_device *vdev, u8 status)
277 {
278 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
279 	/* We should never be setting status to 0. */
280 	BUG_ON(status == 0);
281 	vp_iowrite8(status, &vp_dev->common->device_status);
282 }
283 
vp_reset(struct virtio_device * vdev)284 static void vp_reset(struct virtio_device *vdev)
285 {
286 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
287 	/* 0 status means a reset. */
288 	vp_iowrite8(0, &vp_dev->common->device_status);
289 	/* After writing 0 to device_status, the driver MUST wait for a read of
290 	 * device_status to return 0 before reinitializing the device.
291 	 * This will flush out the status write, and flush in device writes,
292 	 * including MSI-X interrupts, if any.
293 	 */
294 	while (vp_ioread8(&vp_dev->common->device_status))
295 		msleep(1);
296 	/* Flush pending VQ/configuration callbacks. */
297 	vp_synchronize_vectors(vdev);
298 }
299 
vp_config_vector(struct virtio_pci_device * vp_dev,u16 vector)300 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
301 {
302 	/* Setup the vector used for configuration events */
303 	vp_iowrite16(vector, &vp_dev->common->msix_config);
304 	/* Verify we had enough resources to assign the vector */
305 	/* Will also flush the write out to device */
306 	return vp_ioread16(&vp_dev->common->msix_config);
307 }
308 
setup_vq(struct virtio_pci_device * vp_dev,struct virtio_pci_vq_info * info,unsigned index,void (* callback)(struct virtqueue * vq),const char * name,bool ctx,u16 msix_vec)309 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
310 				  struct virtio_pci_vq_info *info,
311 				  unsigned index,
312 				  void (*callback)(struct virtqueue *vq),
313 				  const char *name,
314 				  bool ctx,
315 				  u16 msix_vec)
316 {
317 	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
318 	struct virtqueue *vq;
319 	u16 num, off;
320 	int err;
321 
322 	if (index >= vp_ioread16(&cfg->num_queues))
323 		return ERR_PTR(-ENOENT);
324 
325 	/* Select the queue we're interested in */
326 	vp_iowrite16(index, &cfg->queue_select);
327 
328 	/* Check if queue is either not available or already active. */
329 	num = vp_ioread16(&cfg->queue_size);
330 	if (!num || vp_ioread16(&cfg->queue_enable))
331 		return ERR_PTR(-ENOENT);
332 
333 	if (num & (num - 1)) {
334 		dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
335 		return ERR_PTR(-EINVAL);
336 	}
337 
338 	/* get offset of notification word for this vq */
339 	off = vp_ioread16(&cfg->queue_notify_off);
340 
341 	info->msix_vector = msix_vec;
342 
343 	/* create the vring */
344 	vq = vring_create_virtqueue(index, num,
345 				    SMP_CACHE_BYTES, &vp_dev->vdev,
346 				    true, true, ctx,
347 				    vp_notify, callback, name);
348 	if (!vq)
349 		return ERR_PTR(-ENOMEM);
350 
351 	/* activate the queue */
352 	vp_iowrite16(virtqueue_get_vring_size(vq), &cfg->queue_size);
353 	vp_iowrite64_twopart(virtqueue_get_desc_addr(vq),
354 			     &cfg->queue_desc_lo, &cfg->queue_desc_hi);
355 	vp_iowrite64_twopart(virtqueue_get_avail_addr(vq),
356 			     &cfg->queue_avail_lo, &cfg->queue_avail_hi);
357 	vp_iowrite64_twopart(virtqueue_get_used_addr(vq),
358 			     &cfg->queue_used_lo, &cfg->queue_used_hi);
359 
360 	if (vp_dev->notify_base) {
361 		/* offset should not wrap */
362 		if ((u64)off * vp_dev->notify_offset_multiplier + 2
363 		    > vp_dev->notify_len) {
364 			dev_warn(&vp_dev->pci_dev->dev,
365 				 "bad notification offset %u (x %u) "
366 				 "for queue %u > %zd",
367 				 off, vp_dev->notify_offset_multiplier,
368 				 index, vp_dev->notify_len);
369 			err = -EINVAL;
370 			goto err_map_notify;
371 		}
372 		vq->priv = (void __force *)vp_dev->notify_base +
373 			off * vp_dev->notify_offset_multiplier;
374 	} else {
375 		vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
376 					  vp_dev->notify_map_cap, 2, 2,
377 					  off * vp_dev->notify_offset_multiplier, 2,
378 					  NULL);
379 	}
380 
381 	if (!vq->priv) {
382 		err = -ENOMEM;
383 		goto err_map_notify;
384 	}
385 
386 	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
387 		vp_iowrite16(msix_vec, &cfg->queue_msix_vector);
388 		msix_vec = vp_ioread16(&cfg->queue_msix_vector);
389 		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
390 			err = -EBUSY;
391 			goto err_assign_vector;
392 		}
393 	}
394 
395 	return vq;
396 
397 err_assign_vector:
398 	if (!vp_dev->notify_base)
399 		pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
400 err_map_notify:
401 	vring_del_virtqueue(vq);
402 	return ERR_PTR(err);
403 }
404 
vp_modern_find_vqs(struct virtio_device * vdev,unsigned nvqs,struct virtqueue * vqs[],vq_callback_t * callbacks[],const char * const names[],const bool * ctx,struct irq_affinity * desc)405 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
406 			      struct virtqueue *vqs[],
407 			      vq_callback_t *callbacks[],
408 			      const char * const names[], const bool *ctx,
409 			      struct irq_affinity *desc)
410 {
411 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
412 	struct virtqueue *vq;
413 	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc);
414 
415 	if (rc)
416 		return rc;
417 
418 	/* Select and activate all queues. Has to be done last: once we do
419 	 * this, there's no way to go back except reset.
420 	 */
421 	list_for_each_entry(vq, &vdev->vqs, list) {
422 		vp_iowrite16(vq->index, &vp_dev->common->queue_select);
423 		vp_iowrite16(1, &vp_dev->common->queue_enable);
424 	}
425 
426 	return 0;
427 }
428 
del_vq(struct virtio_pci_vq_info * info)429 static void del_vq(struct virtio_pci_vq_info *info)
430 {
431 	struct virtqueue *vq = info->vq;
432 	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
433 
434 	vp_iowrite16(vq->index, &vp_dev->common->queue_select);
435 
436 	if (vp_dev->msix_enabled) {
437 		vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
438 			     &vp_dev->common->queue_msix_vector);
439 		/* Flush the write out to device */
440 		vp_ioread16(&vp_dev->common->queue_msix_vector);
441 	}
442 
443 	if (!vp_dev->notify_base)
444 		pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
445 
446 	vring_del_virtqueue(vq);
447 }
448 
449 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
450 	.get		= NULL,
451 	.set		= NULL,
452 	.generation	= vp_generation,
453 	.get_status	= vp_get_status,
454 	.set_status	= vp_set_status,
455 	.reset		= vp_reset,
456 	.find_vqs	= vp_modern_find_vqs,
457 	.del_vqs	= vp_del_vqs,
458 	.get_features	= vp_get_features,
459 	.finalize_features = vp_finalize_features,
460 	.bus_name	= vp_bus_name,
461 	.set_vq_affinity = vp_set_vq_affinity,
462 	.get_vq_affinity = vp_get_vq_affinity,
463 };
464 
465 static const struct virtio_config_ops virtio_pci_config_ops = {
466 	.get		= vp_get,
467 	.set		= vp_set,
468 	.generation	= vp_generation,
469 	.get_status	= vp_get_status,
470 	.set_status	= vp_set_status,
471 	.reset		= vp_reset,
472 	.find_vqs	= vp_modern_find_vqs,
473 	.del_vqs	= vp_del_vqs,
474 	.get_features	= vp_get_features,
475 	.finalize_features = vp_finalize_features,
476 	.bus_name	= vp_bus_name,
477 	.set_vq_affinity = vp_set_vq_affinity,
478 	.get_vq_affinity = vp_get_vq_affinity,
479 };
480 
481 /**
482  * virtio_pci_find_capability - walk capabilities to find device info.
483  * @dev: the pci device
484  * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
485  * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
486  *
487  * Returns offset of the capability, or 0.
488  */
virtio_pci_find_capability(struct pci_dev * dev,u8 cfg_type,u32 ioresource_types,int * bars)489 static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
490 					     u32 ioresource_types, int *bars)
491 {
492 	int pos;
493 
494 	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
495 	     pos > 0;
496 	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
497 		u8 type, bar;
498 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
499 							 cfg_type),
500 				     &type);
501 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
502 							 bar),
503 				     &bar);
504 
505 		/* Ignore structures with reserved BAR values */
506 		if (bar > 0x5)
507 			continue;
508 
509 		if (type == cfg_type) {
510 			if (pci_resource_len(dev, bar) &&
511 			    pci_resource_flags(dev, bar) & ioresource_types) {
512 				*bars |= (1 << bar);
513 				return pos;
514 			}
515 		}
516 	}
517 	return 0;
518 }
519 
520 /* This is part of the ABI.  Don't screw with it. */
check_offsets(void)521 static inline void check_offsets(void)
522 {
523 	/* Note: disk space was harmed in compilation of this function. */
524 	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
525 		     offsetof(struct virtio_pci_cap, cap_vndr));
526 	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
527 		     offsetof(struct virtio_pci_cap, cap_next));
528 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
529 		     offsetof(struct virtio_pci_cap, cap_len));
530 	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
531 		     offsetof(struct virtio_pci_cap, cfg_type));
532 	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
533 		     offsetof(struct virtio_pci_cap, bar));
534 	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
535 		     offsetof(struct virtio_pci_cap, offset));
536 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
537 		     offsetof(struct virtio_pci_cap, length));
538 	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
539 		     offsetof(struct virtio_pci_notify_cap,
540 			      notify_off_multiplier));
541 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
542 		     offsetof(struct virtio_pci_common_cfg,
543 			      device_feature_select));
544 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
545 		     offsetof(struct virtio_pci_common_cfg, device_feature));
546 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
547 		     offsetof(struct virtio_pci_common_cfg,
548 			      guest_feature_select));
549 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
550 		     offsetof(struct virtio_pci_common_cfg, guest_feature));
551 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
552 		     offsetof(struct virtio_pci_common_cfg, msix_config));
553 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
554 		     offsetof(struct virtio_pci_common_cfg, num_queues));
555 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
556 		     offsetof(struct virtio_pci_common_cfg, device_status));
557 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
558 		     offsetof(struct virtio_pci_common_cfg, config_generation));
559 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
560 		     offsetof(struct virtio_pci_common_cfg, queue_select));
561 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
562 		     offsetof(struct virtio_pci_common_cfg, queue_size));
563 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
564 		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
565 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
566 		     offsetof(struct virtio_pci_common_cfg, queue_enable));
567 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
568 		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
569 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
570 		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
571 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
572 		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
573 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
574 		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
575 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
576 		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
577 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
578 		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
579 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
580 		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
581 }
582 
583 /* the PCI probing function */
virtio_pci_modern_probe(struct virtio_pci_device * vp_dev)584 int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
585 {
586 	struct pci_dev *pci_dev = vp_dev->pci_dev;
587 	int err, common, isr, notify, device;
588 	u32 notify_length;
589 	u32 notify_offset;
590 
591 	check_offsets();
592 
593 	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
594 	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
595 		return -ENODEV;
596 
597 	if (pci_dev->device < 0x1040) {
598 		/* Transitional devices: use the PCI subsystem device id as
599 		 * virtio device id, same as legacy driver always did.
600 		 */
601 		vp_dev->vdev.id.device = pci_dev->subsystem_device;
602 	} else {
603 		/* Modern devices: simply use PCI device id, but start from 0x1040. */
604 		vp_dev->vdev.id.device = pci_dev->device - 0x1040;
605 	}
606 	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
607 
608 	/* check for a common config: if not, use legacy mode (bar 0). */
609 	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
610 					    IORESOURCE_IO | IORESOURCE_MEM,
611 					    &vp_dev->modern_bars);
612 	if (!common) {
613 		dev_info(&pci_dev->dev,
614 			 "virtio_pci: leaving for legacy driver\n");
615 		return -ENODEV;
616 	}
617 
618 	/* If common is there, these should be too... */
619 	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
620 					 IORESOURCE_IO | IORESOURCE_MEM,
621 					 &vp_dev->modern_bars);
622 	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
623 					    IORESOURCE_IO | IORESOURCE_MEM,
624 					    &vp_dev->modern_bars);
625 	if (!isr || !notify) {
626 		dev_err(&pci_dev->dev,
627 			"virtio_pci: missing capabilities %i/%i/%i\n",
628 			common, isr, notify);
629 		return -EINVAL;
630 	}
631 
632 	err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
633 	if (err)
634 		err = dma_set_mask_and_coherent(&pci_dev->dev,
635 						DMA_BIT_MASK(32));
636 	if (err)
637 		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
638 
639 	/* Device capability is only mandatory for devices that have
640 	 * device-specific configuration.
641 	 */
642 	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
643 					    IORESOURCE_IO | IORESOURCE_MEM,
644 					    &vp_dev->modern_bars);
645 
646 	err = pci_request_selected_regions(pci_dev, vp_dev->modern_bars,
647 					   "virtio-pci-modern");
648 	if (err)
649 		return err;
650 
651 	err = -EINVAL;
652 	vp_dev->common = map_capability(pci_dev, common,
653 					sizeof(struct virtio_pci_common_cfg), 4,
654 					0, sizeof(struct virtio_pci_common_cfg),
655 					NULL);
656 	if (!vp_dev->common)
657 		goto err_map_common;
658 	vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
659 				     0, 1,
660 				     NULL);
661 	if (!vp_dev->isr)
662 		goto err_map_isr;
663 
664 	/* Read notify_off_multiplier from config space. */
665 	pci_read_config_dword(pci_dev,
666 			      notify + offsetof(struct virtio_pci_notify_cap,
667 						notify_off_multiplier),
668 			      &vp_dev->notify_offset_multiplier);
669 	/* Read notify length and offset from config space. */
670 	pci_read_config_dword(pci_dev,
671 			      notify + offsetof(struct virtio_pci_notify_cap,
672 						cap.length),
673 			      &notify_length);
674 
675 	pci_read_config_dword(pci_dev,
676 			      notify + offsetof(struct virtio_pci_notify_cap,
677 						cap.offset),
678 			      &notify_offset);
679 
680 	/* We don't know how many VQs we'll map, ahead of the time.
681 	 * If notify length is small, map it all now.
682 	 * Otherwise, map each VQ individually later.
683 	 */
684 	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
685 		vp_dev->notify_base = map_capability(pci_dev, notify, 2, 2,
686 						     0, notify_length,
687 						     &vp_dev->notify_len);
688 		if (!vp_dev->notify_base)
689 			goto err_map_notify;
690 	} else {
691 		vp_dev->notify_map_cap = notify;
692 	}
693 
694 	/* Again, we don't know how much we should map, but PAGE_SIZE
695 	 * is more than enough for all existing devices.
696 	 */
697 	if (device) {
698 		vp_dev->device = map_capability(pci_dev, device, 0, 4,
699 						0, PAGE_SIZE,
700 						&vp_dev->device_len);
701 		if (!vp_dev->device)
702 			goto err_map_device;
703 
704 		vp_dev->vdev.config = &virtio_pci_config_ops;
705 	} else {
706 		vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
707 	}
708 
709 	vp_dev->config_vector = vp_config_vector;
710 	vp_dev->setup_vq = setup_vq;
711 	vp_dev->del_vq = del_vq;
712 
713 	return 0;
714 
715 err_map_device:
716 	if (vp_dev->notify_base)
717 		pci_iounmap(pci_dev, vp_dev->notify_base);
718 err_map_notify:
719 	pci_iounmap(pci_dev, vp_dev->isr);
720 err_map_isr:
721 	pci_iounmap(pci_dev, vp_dev->common);
722 err_map_common:
723 	return err;
724 }
725 
virtio_pci_modern_remove(struct virtio_pci_device * vp_dev)726 void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
727 {
728 	struct pci_dev *pci_dev = vp_dev->pci_dev;
729 
730 	if (vp_dev->device)
731 		pci_iounmap(pci_dev, vp_dev->device);
732 	if (vp_dev->notify_base)
733 		pci_iounmap(pci_dev, vp_dev->notify_base);
734 	pci_iounmap(pci_dev, vp_dev->isr);
735 	pci_iounmap(pci_dev, vp_dev->common);
736 	pci_release_selected_regions(pci_dev, vp_dev->modern_bars);
737 }
738