xref: /linux/drivers/virtio/virtio_pci_modern_dev.c (revision 4eca0ef49af9b2b0c52ef2b58e045ab34629796b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 #include <linux/virtio_pci_modern.h>
4 #include <linux/module.h>
5 #include <linux/pci.h>
6 #include <linux/delay.h>
7 
8 /*
9  * vp_modern_map_capability - map a part of virtio pci capability
10  * @mdev: the modern virtio-pci device
11  * @off: offset of the capability
12  * @minlen: minimal length of the capability
13  * @align: align requirement
14  * @start: start from the capability
15  * @size: map size
16  * @len: the length that is actually mapped
17  * @pa: physical address of the capability
18  *
19  * Returns the io address of for the part of the capability
20  */
21 static void __iomem *
22 vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
23 			 size_t minlen, u32 align, u32 start, u32 size,
24 			 size_t *len, resource_size_t *pa)
25 {
26 	struct pci_dev *dev = mdev->pci_dev;
27 	u8 bar;
28 	u32 offset, length;
29 	void __iomem *p;
30 
31 	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
32 						 bar),
33 			     &bar);
34 	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
35 			     &offset);
36 	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
37 			      &length);
38 
39 	/* Check if the BAR may have changed since we requested the region. */
40 	if (bar >= PCI_STD_NUM_BARS || !(mdev->modern_bars & (1 << bar))) {
41 		dev_err(&dev->dev,
42 			"virtio_pci: bar unexpectedly changed to %u\n", bar);
43 		return NULL;
44 	}
45 
46 	if (length <= start) {
47 		dev_err(&dev->dev,
48 			"virtio_pci: bad capability len %u (>%u expected)\n",
49 			length, start);
50 		return NULL;
51 	}
52 
53 	if (length - start < minlen) {
54 		dev_err(&dev->dev,
55 			"virtio_pci: bad capability len %u (>=%zu expected)\n",
56 			length, minlen);
57 		return NULL;
58 	}
59 
60 	length -= start;
61 
62 	if (start + offset < offset) {
63 		dev_err(&dev->dev,
64 			"virtio_pci: map wrap-around %u+%u\n",
65 			start, offset);
66 		return NULL;
67 	}
68 
69 	offset += start;
70 
71 	if (offset & (align - 1)) {
72 		dev_err(&dev->dev,
73 			"virtio_pci: offset %u not aligned to %u\n",
74 			offset, align);
75 		return NULL;
76 	}
77 
78 	if (length > size)
79 		length = size;
80 
81 	if (len)
82 		*len = length;
83 
84 	if (minlen + offset < minlen ||
85 	    minlen + offset > pci_resource_len(dev, bar)) {
86 		dev_err(&dev->dev,
87 			"virtio_pci: map virtio %zu@%u "
88 			"out of range on bar %i length %lu\n",
89 			minlen, offset,
90 			bar, (unsigned long)pci_resource_len(dev, bar));
91 		return NULL;
92 	}
93 
94 	p = pci_iomap_range(dev, bar, offset, length);
95 	if (!p)
96 		dev_err(&dev->dev,
97 			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
98 			length, offset, bar);
99 	else if (pa)
100 		*pa = pci_resource_start(dev, bar) + offset;
101 
102 	return p;
103 }
104 
105 /**
106  * virtio_pci_find_capability - walk capabilities to find device info.
107  * @dev: the pci device
108  * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
109  * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
110  * @bars: the bitmask of BARs
111  *
112  * Returns offset of the capability, or 0.
113  */
114 static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
115 					     u32 ioresource_types, int *bars)
116 {
117 	int pos;
118 
119 	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
120 	     pos > 0;
121 	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
122 		u8 type, bar;
123 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
124 							 cfg_type),
125 				     &type);
126 		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
127 							 bar),
128 				     &bar);
129 
130 		/* Ignore structures with reserved BAR values */
131 		if (bar >= PCI_STD_NUM_BARS)
132 			continue;
133 
134 		if (type == cfg_type) {
135 			if (pci_resource_len(dev, bar) &&
136 			    pci_resource_flags(dev, bar) & ioresource_types) {
137 				*bars |= (1 << bar);
138 				return pos;
139 			}
140 		}
141 	}
142 	return 0;
143 }
144 
145 /* This is part of the ABI.  Don't screw with it. */
146 static inline void check_offsets(void)
147 {
148 	/* Note: disk space was harmed in compilation of this function. */
149 	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
150 		     offsetof(struct virtio_pci_cap, cap_vndr));
151 	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
152 		     offsetof(struct virtio_pci_cap, cap_next));
153 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
154 		     offsetof(struct virtio_pci_cap, cap_len));
155 	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
156 		     offsetof(struct virtio_pci_cap, cfg_type));
157 	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
158 		     offsetof(struct virtio_pci_cap, bar));
159 	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
160 		     offsetof(struct virtio_pci_cap, offset));
161 	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
162 		     offsetof(struct virtio_pci_cap, length));
163 	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
164 		     offsetof(struct virtio_pci_notify_cap,
165 			      notify_off_multiplier));
166 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
167 		     offsetof(struct virtio_pci_common_cfg,
168 			      device_feature_select));
169 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
170 		     offsetof(struct virtio_pci_common_cfg, device_feature));
171 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
172 		     offsetof(struct virtio_pci_common_cfg,
173 			      guest_feature_select));
174 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
175 		     offsetof(struct virtio_pci_common_cfg, guest_feature));
176 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
177 		     offsetof(struct virtio_pci_common_cfg, msix_config));
178 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
179 		     offsetof(struct virtio_pci_common_cfg, num_queues));
180 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
181 		     offsetof(struct virtio_pci_common_cfg, device_status));
182 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
183 		     offsetof(struct virtio_pci_common_cfg, config_generation));
184 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
185 		     offsetof(struct virtio_pci_common_cfg, queue_select));
186 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
187 		     offsetof(struct virtio_pci_common_cfg, queue_size));
188 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
189 		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
190 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
191 		     offsetof(struct virtio_pci_common_cfg, queue_enable));
192 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
193 		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
194 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
195 		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
196 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
197 		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
198 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
199 		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
200 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
201 		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
202 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
203 		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
204 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
205 		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
206 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NDATA !=
207 		     offsetof(struct virtio_pci_modern_common_cfg, queue_notify_data));
208 	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_RESET !=
209 		     offsetof(struct virtio_pci_modern_common_cfg, queue_reset));
210 }
211 
212 /*
213  * vp_modern_probe: probe the modern virtio pci device, note that the
214  * caller is required to enable PCI device before calling this function.
215  * @mdev: the modern virtio-pci device
216  *
217  * Return 0 on succeed otherwise fail
218  */
219 int vp_modern_probe(struct virtio_pci_modern_device *mdev)
220 {
221 	struct pci_dev *pci_dev = mdev->pci_dev;
222 	int err, common, isr, notify, device;
223 	u32 notify_length;
224 	u32 notify_offset;
225 	int devid;
226 
227 	check_offsets();
228 
229 	if (mdev->device_id_check) {
230 		devid = mdev->device_id_check(pci_dev);
231 		if (devid < 0)
232 			return devid;
233 		mdev->id.device = devid;
234 	} else {
235 		/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
236 		if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
237 			return -ENODEV;
238 
239 		if (pci_dev->device < 0x1040) {
240 			/* Transitional devices: use the PCI subsystem device id as
241 			 * virtio device id, same as legacy driver always did.
242 			 */
243 			mdev->id.device = pci_dev->subsystem_device;
244 		} else {
245 			/* Modern devices: simply use PCI device id, but start from 0x1040. */
246 			mdev->id.device = pci_dev->device - 0x1040;
247 		}
248 	}
249 	mdev->id.vendor = pci_dev->subsystem_vendor;
250 
251 	/* check for a common config: if not, use legacy mode (bar 0). */
252 	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
253 					    IORESOURCE_IO | IORESOURCE_MEM,
254 					    &mdev->modern_bars);
255 	if (!common) {
256 		dev_info(&pci_dev->dev,
257 			 "virtio_pci: leaving for legacy driver\n");
258 		return -ENODEV;
259 	}
260 
261 	/* If common is there, these should be too... */
262 	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
263 					 IORESOURCE_IO | IORESOURCE_MEM,
264 					 &mdev->modern_bars);
265 	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
266 					    IORESOURCE_IO | IORESOURCE_MEM,
267 					    &mdev->modern_bars);
268 	if (!isr || !notify) {
269 		dev_err(&pci_dev->dev,
270 			"virtio_pci: missing capabilities %i/%i/%i\n",
271 			common, isr, notify);
272 		return -EINVAL;
273 	}
274 
275 	err = dma_set_mask_and_coherent(&pci_dev->dev,
276 					mdev->dma_mask ? : DMA_BIT_MASK(64));
277 	if (err)
278 		err = dma_set_mask_and_coherent(&pci_dev->dev,
279 						DMA_BIT_MASK(32));
280 	if (err)
281 		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
282 
283 	/* Device capability is only mandatory for devices that have
284 	 * device-specific configuration.
285 	 */
286 	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
287 					    IORESOURCE_IO | IORESOURCE_MEM,
288 					    &mdev->modern_bars);
289 
290 	err = pci_request_selected_regions(pci_dev, mdev->modern_bars,
291 					   "virtio-pci-modern");
292 	if (err)
293 		return err;
294 
295 	err = -EINVAL;
296 	mdev->common = vp_modern_map_capability(mdev, common,
297 			      sizeof(struct virtio_pci_common_cfg), 4, 0,
298 			      offsetofend(struct virtio_pci_modern_common_cfg,
299 					  queue_reset),
300 			      &mdev->common_len, NULL);
301 	if (!mdev->common)
302 		goto err_map_common;
303 	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
304 					     0, 1,
305 					     NULL, NULL);
306 	if (!mdev->isr)
307 		goto err_map_isr;
308 
309 	/* Read notify_off_multiplier from config space. */
310 	pci_read_config_dword(pci_dev,
311 			      notify + offsetof(struct virtio_pci_notify_cap,
312 						notify_off_multiplier),
313 			      &mdev->notify_offset_multiplier);
314 	/* Read notify length and offset from config space. */
315 	pci_read_config_dword(pci_dev,
316 			      notify + offsetof(struct virtio_pci_notify_cap,
317 						cap.length),
318 			      &notify_length);
319 
320 	pci_read_config_dword(pci_dev,
321 			      notify + offsetof(struct virtio_pci_notify_cap,
322 						cap.offset),
323 			      &notify_offset);
324 
325 	/* We don't know how many VQs we'll map, ahead of the time.
326 	 * If notify length is small, map it all now.
327 	 * Otherwise, map each VQ individually later.
328 	 */
329 	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
330 		mdev->notify_base = vp_modern_map_capability(mdev, notify,
331 							     2, 2,
332 							     0, notify_length,
333 							     &mdev->notify_len,
334 							     &mdev->notify_pa);
335 		if (!mdev->notify_base)
336 			goto err_map_notify;
337 	} else {
338 		mdev->notify_map_cap = notify;
339 	}
340 
341 	/* Again, we don't know how much we should map, but PAGE_SIZE
342 	 * is more than enough for all existing devices.
343 	 */
344 	if (device) {
345 		mdev->device = vp_modern_map_capability(mdev, device, 0, 4,
346 							0, PAGE_SIZE,
347 							&mdev->device_len,
348 							NULL);
349 		if (!mdev->device)
350 			goto err_map_device;
351 	}
352 
353 	return 0;
354 
355 err_map_device:
356 	if (mdev->notify_base)
357 		pci_iounmap(pci_dev, mdev->notify_base);
358 err_map_notify:
359 	pci_iounmap(pci_dev, mdev->isr);
360 err_map_isr:
361 	pci_iounmap(pci_dev, mdev->common);
362 err_map_common:
363 	pci_release_selected_regions(pci_dev, mdev->modern_bars);
364 	return err;
365 }
366 EXPORT_SYMBOL_GPL(vp_modern_probe);
367 
368 /*
369  * vp_modern_remove: remove and cleanup the modern virtio pci device
370  * @mdev: the modern virtio-pci device
371  */
372 void vp_modern_remove(struct virtio_pci_modern_device *mdev)
373 {
374 	struct pci_dev *pci_dev = mdev->pci_dev;
375 
376 	if (mdev->device)
377 		pci_iounmap(pci_dev, mdev->device);
378 	if (mdev->notify_base)
379 		pci_iounmap(pci_dev, mdev->notify_base);
380 	pci_iounmap(pci_dev, mdev->isr);
381 	pci_iounmap(pci_dev, mdev->common);
382 	pci_release_selected_regions(pci_dev, mdev->modern_bars);
383 }
384 EXPORT_SYMBOL_GPL(vp_modern_remove);
385 
386 /*
387  * vp_modern_get_features - get features from device
388  * @mdev: the modern virtio-pci device
389  *
390  * Returns the features read from the device
391  */
392 u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
393 {
394 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
395 
396 	u64 features;
397 
398 	vp_iowrite32(0, &cfg->device_feature_select);
399 	features = vp_ioread32(&cfg->device_feature);
400 	vp_iowrite32(1, &cfg->device_feature_select);
401 	features |= ((u64)vp_ioread32(&cfg->device_feature) << 32);
402 
403 	return features;
404 }
405 EXPORT_SYMBOL_GPL(vp_modern_get_features);
406 
407 /*
408  * vp_modern_get_driver_features - get driver features from device
409  * @mdev: the modern virtio-pci device
410  *
411  * Returns the driver features read from the device
412  */
413 u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev)
414 {
415 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
416 
417 	u64 features;
418 
419 	vp_iowrite32(0, &cfg->guest_feature_select);
420 	features = vp_ioread32(&cfg->guest_feature);
421 	vp_iowrite32(1, &cfg->guest_feature_select);
422 	features |= ((u64)vp_ioread32(&cfg->guest_feature) << 32);
423 
424 	return features;
425 }
426 EXPORT_SYMBOL_GPL(vp_modern_get_driver_features);
427 
428 /*
429  * vp_modern_set_features - set features to device
430  * @mdev: the modern virtio-pci device
431  * @features: the features set to device
432  */
433 void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
434 			    u64 features)
435 {
436 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
437 
438 	vp_iowrite32(0, &cfg->guest_feature_select);
439 	vp_iowrite32((u32)features, &cfg->guest_feature);
440 	vp_iowrite32(1, &cfg->guest_feature_select);
441 	vp_iowrite32(features >> 32, &cfg->guest_feature);
442 }
443 EXPORT_SYMBOL_GPL(vp_modern_set_features);
444 
445 /*
446  * vp_modern_generation - get the device genreation
447  * @mdev: the modern virtio-pci device
448  *
449  * Returns the genreation read from device
450  */
451 u32 vp_modern_generation(struct virtio_pci_modern_device *mdev)
452 {
453 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
454 
455 	return vp_ioread8(&cfg->config_generation);
456 }
457 EXPORT_SYMBOL_GPL(vp_modern_generation);
458 
459 /*
460  * vp_modern_get_status - get the device status
461  * @mdev: the modern virtio-pci device
462  *
463  * Returns the status read from device
464  */
465 u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev)
466 {
467 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
468 
469 	return vp_ioread8(&cfg->device_status);
470 }
471 EXPORT_SYMBOL_GPL(vp_modern_get_status);
472 
473 /*
474  * vp_modern_set_status - set status to device
475  * @mdev: the modern virtio-pci device
476  * @status: the status set to device
477  */
478 void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
479 				 u8 status)
480 {
481 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
482 
483 	/*
484 	 * Per memory-barriers.txt, wmb() is not needed to guarantee
485 	 * that the cache coherent memory writes have completed
486 	 * before writing to the MMIO region.
487 	 */
488 	vp_iowrite8(status, &cfg->device_status);
489 }
490 EXPORT_SYMBOL_GPL(vp_modern_set_status);
491 
492 /*
493  * vp_modern_get_queue_reset - get the queue reset status
494  * @mdev: the modern virtio-pci device
495  * @index: queue index
496  */
497 int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
498 {
499 	struct virtio_pci_modern_common_cfg __iomem *cfg;
500 
501 	cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
502 
503 	vp_iowrite16(index, &cfg->cfg.queue_select);
504 	return vp_ioread16(&cfg->queue_reset);
505 }
506 EXPORT_SYMBOL_GPL(vp_modern_get_queue_reset);
507 
508 /*
509  * vp_modern_set_queue_reset - reset the queue
510  * @mdev: the modern virtio-pci device
511  * @index: queue index
512  */
513 void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
514 {
515 	struct virtio_pci_modern_common_cfg __iomem *cfg;
516 
517 	cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
518 
519 	vp_iowrite16(index, &cfg->cfg.queue_select);
520 	vp_iowrite16(1, &cfg->queue_reset);
521 
522 	while (vp_ioread16(&cfg->queue_reset))
523 		msleep(1);
524 
525 	while (vp_ioread16(&cfg->cfg.queue_enable))
526 		msleep(1);
527 }
528 EXPORT_SYMBOL_GPL(vp_modern_set_queue_reset);
529 
530 /*
531  * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
532  * @mdev: the modern virtio-pci device
533  * @index: queue index
534  * @vector: the config vector
535  *
536  * Returns the config vector read from the device
537  */
538 u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
539 			   u16 index, u16 vector)
540 {
541 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
542 
543 	vp_iowrite16(index, &cfg->queue_select);
544 	vp_iowrite16(vector, &cfg->queue_msix_vector);
545 	/* Flush the write out to device */
546 	return vp_ioread16(&cfg->queue_msix_vector);
547 }
548 EXPORT_SYMBOL_GPL(vp_modern_queue_vector);
549 
550 /*
551  * vp_modern_config_vector - set the vector for config interrupt
552  * @mdev: the modern virtio-pci device
553  * @vector: the config vector
554  *
555  * Returns the config vector read from the device
556  */
557 u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
558 			    u16 vector)
559 {
560 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
561 
562 	/* Setup the vector used for configuration events */
563 	vp_iowrite16(vector, &cfg->msix_config);
564 	/* Verify we had enough resources to assign the vector */
565 	/* Will also flush the write out to device */
566 	return vp_ioread16(&cfg->msix_config);
567 }
568 EXPORT_SYMBOL_GPL(vp_modern_config_vector);
569 
570 /*
571  * vp_modern_queue_address - set the virtqueue address
572  * @mdev: the modern virtio-pci device
573  * @index: the queue index
574  * @desc_addr: address of the descriptor area
575  * @driver_addr: address of the driver area
576  * @device_addr: address of the device area
577  */
578 void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
579 			     u16 index, u64 desc_addr, u64 driver_addr,
580 			     u64 device_addr)
581 {
582 	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
583 
584 	vp_iowrite16(index, &cfg->queue_select);
585 
586 	vp_iowrite64_twopart(desc_addr, &cfg->queue_desc_lo,
587 			     &cfg->queue_desc_hi);
588 	vp_iowrite64_twopart(driver_addr, &cfg->queue_avail_lo,
589 			     &cfg->queue_avail_hi);
590 	vp_iowrite64_twopart(device_addr, &cfg->queue_used_lo,
591 			     &cfg->queue_used_hi);
592 }
593 EXPORT_SYMBOL_GPL(vp_modern_queue_address);
594 
595 /*
596  * vp_modern_set_queue_enable - enable a virtqueue
597  * @mdev: the modern virtio-pci device
598  * @index: the queue index
599  * @enable: whether the virtqueue is enable or not
600  */
601 void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
602 				u16 index, bool enable)
603 {
604 	vp_iowrite16(index, &mdev->common->queue_select);
605 	vp_iowrite16(enable, &mdev->common->queue_enable);
606 }
607 EXPORT_SYMBOL_GPL(vp_modern_set_queue_enable);
608 
609 /*
610  * vp_modern_get_queue_enable - enable a virtqueue
611  * @mdev: the modern virtio-pci device
612  * @index: the queue index
613  *
614  * Returns whether a virtqueue is enabled or not
615  */
616 bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
617 				u16 index)
618 {
619 	vp_iowrite16(index, &mdev->common->queue_select);
620 
621 	return vp_ioread16(&mdev->common->queue_enable);
622 }
623 EXPORT_SYMBOL_GPL(vp_modern_get_queue_enable);
624 
625 /*
626  * vp_modern_set_queue_size - set size for a virtqueue
627  * @mdev: the modern virtio-pci device
628  * @index: the queue index
629  * @size: the size of the virtqueue
630  */
631 void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
632 			      u16 index, u16 size)
633 {
634 	vp_iowrite16(index, &mdev->common->queue_select);
635 	vp_iowrite16(size, &mdev->common->queue_size);
636 
637 }
638 EXPORT_SYMBOL_GPL(vp_modern_set_queue_size);
639 
640 /*
641  * vp_modern_get_queue_size - get size for a virtqueue
642  * @mdev: the modern virtio-pci device
643  * @index: the queue index
644  *
645  * Returns the size of the virtqueue
646  */
647 u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
648 			     u16 index)
649 {
650 	vp_iowrite16(index, &mdev->common->queue_select);
651 
652 	return vp_ioread16(&mdev->common->queue_size);
653 
654 }
655 EXPORT_SYMBOL_GPL(vp_modern_get_queue_size);
656 
657 /*
658  * vp_modern_get_num_queues - get the number of virtqueues
659  * @mdev: the modern virtio-pci device
660  *
661  * Returns the number of virtqueues
662  */
663 u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev)
664 {
665 	return vp_ioread16(&mdev->common->num_queues);
666 }
667 EXPORT_SYMBOL_GPL(vp_modern_get_num_queues);
668 
669 /*
670  * vp_modern_get_queue_notify_off - get notification offset for a virtqueue
671  * @mdev: the modern virtio-pci device
672  * @index: the queue index
673  *
674  * Returns the notification offset for a virtqueue
675  */
676 static u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
677 					  u16 index)
678 {
679 	vp_iowrite16(index, &mdev->common->queue_select);
680 
681 	return vp_ioread16(&mdev->common->queue_notify_off);
682 }
683 
684 /*
685  * vp_modern_map_vq_notify - map notification area for a
686  * specific virtqueue
687  * @mdev: the modern virtio-pci device
688  * @index: the queue index
689  * @pa: the pointer to the physical address of the nofity area
690  *
691  * Returns the address of the notification area
692  */
693 void __iomem *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
694 				      u16 index, resource_size_t *pa)
695 {
696 	u16 off = vp_modern_get_queue_notify_off(mdev, index);
697 
698 	if (mdev->notify_base) {
699 		/* offset should not wrap */
700 		if ((u64)off * mdev->notify_offset_multiplier + 2
701 			> mdev->notify_len) {
702 			dev_warn(&mdev->pci_dev->dev,
703 				 "bad notification offset %u (x %u) "
704 				 "for queue %u > %zd",
705 				 off, mdev->notify_offset_multiplier,
706 				 index, mdev->notify_len);
707 			return NULL;
708 		}
709 		if (pa)
710 			*pa = mdev->notify_pa +
711 			      off * mdev->notify_offset_multiplier;
712 		return mdev->notify_base + off * mdev->notify_offset_multiplier;
713 	} else {
714 		return vp_modern_map_capability(mdev,
715 				       mdev->notify_map_cap, 2, 2,
716 				       off * mdev->notify_offset_multiplier, 2,
717 				       NULL, pa);
718 	}
719 }
720 EXPORT_SYMBOL_GPL(vp_modern_map_vq_notify);
721 
722 MODULE_VERSION("0.1");
723 MODULE_DESCRIPTION("Modern Virtio PCI Device");
724 MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
725 MODULE_LICENSE("GPL");
726