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
  7/*
  8 * vp_modern_map_capability - map a part of virtio pci capability
  9 * @mdev: the modern virtio-pci device
 10 * @off: offset of the capability
 11 * @minlen: minimal length of the capability
 12 * @align: align requirement
 13 * @start: start from the capability
 14 * @size: map size
 15 * @len: the length that is actually mapped
 16 * @pa: physical address of the capability
 17 *
 18 * Returns the io address of for the part of the capability
 19 */
 20static void __iomem *
 21vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
 22			 size_t minlen, u32 align, u32 start, u32 size,
 23			 size_t *len, resource_size_t *pa)
 24{
 25	struct pci_dev *dev = mdev->pci_dev;
 26	u8 bar;
 27	u32 offset, length;
 28	void __iomem *p;
 29
 30	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
 31						 bar),
 32			     &bar);
 33	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
 34			     &offset);
 35	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
 36			      &length);
 37
 38	if (length <= start) {
 39		dev_err(&dev->dev,
 40			"virtio_pci: bad capability len %u (>%u expected)\n",
 41			length, start);
 42		return NULL;
 43	}
 44
 45	if (length - start < minlen) {
 46		dev_err(&dev->dev,
 47			"virtio_pci: bad capability len %u (>=%zu expected)\n",
 48			length, minlen);
 49		return NULL;
 50	}
 51
 52	length -= start;
 53
 54	if (start + offset < offset) {
 55		dev_err(&dev->dev,
 56			"virtio_pci: map wrap-around %u+%u\n",
 57			start, offset);
 58		return NULL;
 59	}
 60
 61	offset += start;
 62
 63	if (offset & (align - 1)) {
 64		dev_err(&dev->dev,
 65			"virtio_pci: offset %u not aligned to %u\n",
 66			offset, align);
 67		return NULL;
 68	}
 69
 70	if (length > size)
 71		length = size;
 72
 73	if (len)
 74		*len = length;
 75
 76	if (minlen + offset < minlen ||
 77	    minlen + offset > pci_resource_len(dev, bar)) {
 78		dev_err(&dev->dev,
 79			"virtio_pci: map virtio %zu@%u "
 80			"out of range on bar %i length %lu\n",
 81			minlen, offset,
 82			bar, (unsigned long)pci_resource_len(dev, bar));
 83		return NULL;
 84	}
 85
 86	p = pci_iomap_range(dev, bar, offset, length);
 87	if (!p)
 88		dev_err(&dev->dev,
 89			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
 90			length, offset, bar);
 91	else if (pa)
 92		*pa = pci_resource_start(dev, bar) + offset;
 93
 94	return p;
 95}
 96
 97/**
 98 * virtio_pci_find_capability - walk capabilities to find device info.
 99 * @dev: the pci device
100 * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
101 * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
102 * @bars: the bitmask of BARs
103 *
104 * Returns offset of the capability, or 0.
105 */
106static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
107					     u32 ioresource_types, int *bars)
108{
109	int pos;
110
111	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
112	     pos > 0;
113	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
114		u8 type, bar;
115		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
116							 cfg_type),
117				     &type);
118		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
119							 bar),
120				     &bar);
121
122		/* Ignore structures with reserved BAR values */
123		if (bar > 0x5)
124			continue;
125
126		if (type == cfg_type) {
127			if (pci_resource_len(dev, bar) &&
128			    pci_resource_flags(dev, bar) & ioresource_types) {
129				*bars |= (1 << bar);
130				return pos;
131			}
132		}
133	}
134	return 0;
135}
136
137/* This is part of the ABI.  Don't screw with it. */
138static inline void check_offsets(void)
139{
140	/* Note: disk space was harmed in compilation of this function. */
141	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
142		     offsetof(struct virtio_pci_cap, cap_vndr));
143	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
144		     offsetof(struct virtio_pci_cap, cap_next));
145	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
146		     offsetof(struct virtio_pci_cap, cap_len));
147	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
148		     offsetof(struct virtio_pci_cap, cfg_type));
149	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
150		     offsetof(struct virtio_pci_cap, bar));
151	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
152		     offsetof(struct virtio_pci_cap, offset));
153	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
154		     offsetof(struct virtio_pci_cap, length));
155	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
156		     offsetof(struct virtio_pci_notify_cap,
157			      notify_off_multiplier));
158	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
159		     offsetof(struct virtio_pci_common_cfg,
160			      device_feature_select));
161	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
162		     offsetof(struct virtio_pci_common_cfg, device_feature));
163	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
164		     offsetof(struct virtio_pci_common_cfg,
165			      guest_feature_select));
166	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
167		     offsetof(struct virtio_pci_common_cfg, guest_feature));
168	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
169		     offsetof(struct virtio_pci_common_cfg, msix_config));
170	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
171		     offsetof(struct virtio_pci_common_cfg, num_queues));
172	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
173		     offsetof(struct virtio_pci_common_cfg, device_status));
174	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
175		     offsetof(struct virtio_pci_common_cfg, config_generation));
176	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
177		     offsetof(struct virtio_pci_common_cfg, queue_select));
178	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
179		     offsetof(struct virtio_pci_common_cfg, queue_size));
180	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
181		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
182	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
183		     offsetof(struct virtio_pci_common_cfg, queue_enable));
184	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
185		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
186	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
187		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
188	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
189		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
190	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
191		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
192	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
193		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
194	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
195		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
196	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
197		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
198}
199
200/*
201 * vp_modern_probe: probe the modern virtio pci device, note that the
202 * caller is required to enable PCI device before calling this function.
203 * @mdev: the modern virtio-pci device
204 *
205 * Return 0 on succeed otherwise fail
206 */
207int vp_modern_probe(struct virtio_pci_modern_device *mdev)
208{
209	struct pci_dev *pci_dev = mdev->pci_dev;
210	int err, common, isr, notify, device;
211	u32 notify_length;
212	u32 notify_offset;
213
214	check_offsets();
215
216	mdev->pci_dev = pci_dev;
217
218	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
219	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
220		return -ENODEV;
221
222	if (pci_dev->device < 0x1040) {
223		/* Transitional devices: use the PCI subsystem device id as
224		 * virtio device id, same as legacy driver always did.
225		 */
226		mdev->id.device = pci_dev->subsystem_device;
227	} else {
228		/* Modern devices: simply use PCI device id, but start from 0x1040. */
229		mdev->id.device = pci_dev->device - 0x1040;
230	}
231	mdev->id.vendor = pci_dev->subsystem_vendor;
232
233	/* check for a common config: if not, use legacy mode (bar 0). */
234	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
235					    IORESOURCE_IO | IORESOURCE_MEM,
236					    &mdev->modern_bars);
237	if (!common) {
238		dev_info(&pci_dev->dev,
239			 "virtio_pci: leaving for legacy driver\n");
240		return -ENODEV;
241	}
242
243	/* If common is there, these should be too... */
244	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
245					 IORESOURCE_IO | IORESOURCE_MEM,
246					 &mdev->modern_bars);
247	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
248					    IORESOURCE_IO | IORESOURCE_MEM,
249					    &mdev->modern_bars);
250	if (!isr || !notify) {
251		dev_err(&pci_dev->dev,
252			"virtio_pci: missing capabilities %i/%i/%i\n",
253			common, isr, notify);
254		return -EINVAL;
255	}
256
257	err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
258	if (err)
259		err = dma_set_mask_and_coherent(&pci_dev->dev,
260						DMA_BIT_MASK(32));
261	if (err)
262		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
263
264	/* Device capability is only mandatory for devices that have
265	 * device-specific configuration.
266	 */
267	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
268					    IORESOURCE_IO | IORESOURCE_MEM,
269					    &mdev->modern_bars);
270
271	err = pci_request_selected_regions(pci_dev, mdev->modern_bars,
272					   "virtio-pci-modern");
273	if (err)
274		return err;
275
276	err = -EINVAL;
277	mdev->common = vp_modern_map_capability(mdev, common,
278				      sizeof(struct virtio_pci_common_cfg), 4,
279				      0, sizeof(struct virtio_pci_common_cfg),
280				      NULL, NULL);
281	if (!mdev->common)
282		goto err_map_common;
283	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
284					     0, 1,
285					     NULL, NULL);
286	if (!mdev->isr)
287		goto err_map_isr;
288
289	/* Read notify_off_multiplier from config space. */
290	pci_read_config_dword(pci_dev,
291			      notify + offsetof(struct virtio_pci_notify_cap,
292						notify_off_multiplier),
293			      &mdev->notify_offset_multiplier);
294	/* Read notify length and offset from config space. */
295	pci_read_config_dword(pci_dev,
296			      notify + offsetof(struct virtio_pci_notify_cap,
297						cap.length),
298			      &notify_length);
299
300	pci_read_config_dword(pci_dev,
301			      notify + offsetof(struct virtio_pci_notify_cap,
302						cap.offset),
303			      &notify_offset);
304
305	/* We don't know how many VQs we'll map, ahead of the time.
306	 * If notify length is small, map it all now.
307	 * Otherwise, map each VQ individually later.
308	 */
309	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
310		mdev->notify_base = vp_modern_map_capability(mdev, notify,
311							     2, 2,
312							     0, notify_length,
313							     &mdev->notify_len,
314							     &mdev->notify_pa);
315		if (!mdev->notify_base)
316			goto err_map_notify;
317	} else {
318		mdev->notify_map_cap = notify;
319	}
320
321	/* Again, we don't know how much we should map, but PAGE_SIZE
322	 * is more than enough for all existing devices.
323	 */
324	if (device) {
325		mdev->device = vp_modern_map_capability(mdev, device, 0, 4,
326							0, PAGE_SIZE,
327							&mdev->device_len,
328							NULL);
329		if (!mdev->device)
330			goto err_map_device;
331	}
332
333	return 0;
334
335err_map_device:
336	if (mdev->notify_base)
337		pci_iounmap(pci_dev, mdev->notify_base);
338err_map_notify:
339	pci_iounmap(pci_dev, mdev->isr);
340err_map_isr:
341	pci_iounmap(pci_dev, mdev->common);
342err_map_common:
343	return err;
344}
345EXPORT_SYMBOL_GPL(vp_modern_probe);
346
347/*
348 * vp_modern_probe: remove and cleanup the modern virtio pci device
349 * @mdev: the modern virtio-pci device
350 */
351void vp_modern_remove(struct virtio_pci_modern_device *mdev)
352{
353	struct pci_dev *pci_dev = mdev->pci_dev;
354
355	if (mdev->device)
356		pci_iounmap(pci_dev, mdev->device);
357	if (mdev->notify_base)
358		pci_iounmap(pci_dev, mdev->notify_base);
359	pci_iounmap(pci_dev, mdev->isr);
360	pci_iounmap(pci_dev, mdev->common);
361	pci_release_selected_regions(pci_dev, mdev->modern_bars);
362}
363EXPORT_SYMBOL_GPL(vp_modern_remove);
364
365/*
366 * vp_modern_get_features - get features from device
367 * @mdev: the modern virtio-pci device
368 *
369 * Returns the features read from the device
370 */
371u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
372{
373	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
374
375	u64 features;
376
377	vp_iowrite32(0, &cfg->device_feature_select);
378	features = vp_ioread32(&cfg->device_feature);
379	vp_iowrite32(1, &cfg->device_feature_select);
380	features |= ((u64)vp_ioread32(&cfg->device_feature) << 32);
381
382	return features;
383}
384EXPORT_SYMBOL_GPL(vp_modern_get_features);
385
386/*
387 * vp_modern_get_driver_features - get driver features from device
388 * @mdev: the modern virtio-pci device
389 *
390 * Returns the driver features read from the device
391 */
392u64 vp_modern_get_driver_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->guest_feature_select);
399	features = vp_ioread32(&cfg->guest_feature);
400	vp_iowrite32(1, &cfg->guest_feature_select);
401	features |= ((u64)vp_ioread32(&cfg->guest_feature) << 32);
402
403	return features;
404}
405EXPORT_SYMBOL_GPL(vp_modern_get_driver_features);
406
407/*
408 * vp_modern_set_features - set features to device
409 * @mdev: the modern virtio-pci device
410 * @features: the features set to device
411 */
412void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
413			    u64 features)
414{
415	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
416
417	vp_iowrite32(0, &cfg->guest_feature_select);
418	vp_iowrite32((u32)features, &cfg->guest_feature);
419	vp_iowrite32(1, &cfg->guest_feature_select);
420	vp_iowrite32(features >> 32, &cfg->guest_feature);
421}
422EXPORT_SYMBOL_GPL(vp_modern_set_features);
423
424/*
425 * vp_modern_generation - get the device genreation
426 * @mdev: the modern virtio-pci device
427 *
428 * Returns the genreation read from device
429 */
430u32 vp_modern_generation(struct virtio_pci_modern_device *mdev)
431{
432	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
433
434	return vp_ioread8(&cfg->config_generation);
435}
436EXPORT_SYMBOL_GPL(vp_modern_generation);
437
438/*
439 * vp_modern_get_status - get the device status
440 * @mdev: the modern virtio-pci device
441 *
442 * Returns the status read from device
443 */
444u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev)
445{
446	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
447
448	return vp_ioread8(&cfg->device_status);
449}
450EXPORT_SYMBOL_GPL(vp_modern_get_status);
451
452/*
453 * vp_modern_set_status - set status to device
454 * @mdev: the modern virtio-pci device
455 * @status: the status set to device
456 */
457void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
458				 u8 status)
459{
460	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
461
462	vp_iowrite8(status, &cfg->device_status);
463}
464EXPORT_SYMBOL_GPL(vp_modern_set_status);
465
466/*
467 * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
468 * @mdev: the modern virtio-pci device
469 * @index: queue index
470 * @vector: the config vector
471 *
472 * Returns the config vector read from the device
473 */
474u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
475			   u16 index, u16 vector)
476{
477	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
478
479	vp_iowrite16(index, &cfg->queue_select);
480	vp_iowrite16(vector, &cfg->queue_msix_vector);
481	/* Flush the write out to device */
482	return vp_ioread16(&cfg->queue_msix_vector);
483}
484EXPORT_SYMBOL_GPL(vp_modern_queue_vector);
485
486/*
487 * vp_modern_config_vector - set the vector for config interrupt
488 * @mdev: the modern virtio-pci device
489 * @vector: the config vector
490 *
491 * Returns the config vector read from the device
492 */
493u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
494			    u16 vector)
495{
496	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
497
498	/* Setup the vector used for configuration events */
499	vp_iowrite16(vector, &cfg->msix_config);
500	/* Verify we had enough resources to assign the vector */
501	/* Will also flush the write out to device */
502	return vp_ioread16(&cfg->msix_config);
503}
504EXPORT_SYMBOL_GPL(vp_modern_config_vector);
505
506/*
507 * vp_modern_queue_address - set the virtqueue address
508 * @mdev: the modern virtio-pci device
509 * @index: the queue index
510 * @desc_addr: address of the descriptor area
511 * @driver_addr: address of the driver area
512 * @device_addr: address of the device area
513 */
514void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
515			     u16 index, u64 desc_addr, u64 driver_addr,
516			     u64 device_addr)
517{
518	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
519
520	vp_iowrite16(index, &cfg->queue_select);
521
522	vp_iowrite64_twopart(desc_addr, &cfg->queue_desc_lo,
523			     &cfg->queue_desc_hi);
524	vp_iowrite64_twopart(driver_addr, &cfg->queue_avail_lo,
525			     &cfg->queue_avail_hi);
526	vp_iowrite64_twopart(device_addr, &cfg->queue_used_lo,
527			     &cfg->queue_used_hi);
528}
529EXPORT_SYMBOL_GPL(vp_modern_queue_address);
530
531/*
532 * vp_modern_set_queue_enable - enable a virtqueue
533 * @mdev: the modern virtio-pci device
534 * @index: the queue index
535 * @enable: whether the virtqueue is enable or not
536 */
537void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
538				u16 index, bool enable)
539{
540	vp_iowrite16(index, &mdev->common->queue_select);
541	vp_iowrite16(enable, &mdev->common->queue_enable);
542}
543EXPORT_SYMBOL_GPL(vp_modern_set_queue_enable);
544
545/*
546 * vp_modern_get_queue_enable - enable a virtqueue
547 * @mdev: the modern virtio-pci device
548 * @index: the queue index
549 *
550 * Returns whether a virtqueue is enabled or not
551 */
552bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
553				u16 index)
554{
555	vp_iowrite16(index, &mdev->common->queue_select);
556
557	return vp_ioread16(&mdev->common->queue_enable);
558}
559EXPORT_SYMBOL_GPL(vp_modern_get_queue_enable);
560
561/*
562 * vp_modern_set_queue_size - set size for a virtqueue
563 * @mdev: the modern virtio-pci device
564 * @index: the queue index
565 * @size: the size of the virtqueue
566 */
567void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
568			      u16 index, u16 size)
569{
570	vp_iowrite16(index, &mdev->common->queue_select);
571	vp_iowrite16(size, &mdev->common->queue_size);
572
573}
574EXPORT_SYMBOL_GPL(vp_modern_set_queue_size);
575
576/*
577 * vp_modern_get_queue_size - get size for a virtqueue
578 * @mdev: the modern virtio-pci device
579 * @index: the queue index
580 *
581 * Returns the size of the virtqueue
582 */
583u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
584			     u16 index)
585{
586	vp_iowrite16(index, &mdev->common->queue_select);
587
588	return vp_ioread16(&mdev->common->queue_size);
589
590}
591EXPORT_SYMBOL_GPL(vp_modern_get_queue_size);
592
593/*
594 * vp_modern_get_num_queues - get the number of virtqueues
595 * @mdev: the modern virtio-pci device
596 *
597 * Returns the number of virtqueues
598 */
599u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev)
600{
601	return vp_ioread16(&mdev->common->num_queues);
602}
603EXPORT_SYMBOL_GPL(vp_modern_get_num_queues);
604
605/*
606 * vp_modern_get_queue_notify_off - get notification offset for a virtqueue
607 * @mdev: the modern virtio-pci device
608 * @index: the queue index
609 *
610 * Returns the notification offset for a virtqueue
611 */
612static u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
613					  u16 index)
614{
615	vp_iowrite16(index, &mdev->common->queue_select);
616
617	return vp_ioread16(&mdev->common->queue_notify_off);
618}
619
620/*
621 * vp_modern_map_vq_notify - map notification area for a
622 * specific virtqueue
623 * @mdev: the modern virtio-pci device
624 * @index: the queue index
625 * @pa: the pointer to the physical address of the nofity area
626 *
627 * Returns the address of the notification area
628 */
629void __iomem *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
630				      u16 index, resource_size_t *pa)
631{
632	u16 off = vp_modern_get_queue_notify_off(mdev, index);
633
634	if (mdev->notify_base) {
635		/* offset should not wrap */
636		if ((u64)off * mdev->notify_offset_multiplier + 2
637			> mdev->notify_len) {
638			dev_warn(&mdev->pci_dev->dev,
639				 "bad notification offset %u (x %u) "
640				 "for queue %u > %zd",
641				 off, mdev->notify_offset_multiplier,
642				 index, mdev->notify_len);
643			return NULL;
644		}
645		if (pa)
646			*pa = mdev->notify_pa +
647			      off * mdev->notify_offset_multiplier;
648		return mdev->notify_base + off * mdev->notify_offset_multiplier;
649	} else {
650		return vp_modern_map_capability(mdev,
651				       mdev->notify_map_cap, 2, 2,
652				       off * mdev->notify_offset_multiplier, 2,
653				       NULL, pa);
654	}
655}
656EXPORT_SYMBOL_GPL(vp_modern_map_vq_notify);
657
658MODULE_VERSION("0.1");
659MODULE_DESCRIPTION("Modern Virtio PCI Device");
660MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
661MODULE_LICENSE("GPL");