1 /*
2  * Copyright 2018 Red Hat Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  */
22 #include "nouveau_dmem.h"
23 #include "nouveau_drv.h"
24 #include "nouveau_chan.h"
25 #include "nouveau_dma.h"
26 #include "nouveau_mem.h"
27 #include "nouveau_bo.h"
28 
29 #include <nvif/class.h>
30 #include <nvif/object.h>
31 #include <nvif/if500b.h>
32 #include <nvif/if900b.h>
33 
34 #include <linux/sched/mm.h>
35 #include <linux/hmm.h>
36 
37 /*
38  * FIXME: this is ugly right now we are using TTM to allocate vram and we pin
39  * it in vram while in use. We likely want to overhaul memory management for
40  * nouveau to be more page like (not necessarily with system page size but a
41  * bigger page size) at lowest level and have some shim layer on top that would
42  * provide the same functionality as TTM.
43  */
44 #define DMEM_CHUNK_SIZE (2UL << 20)
45 #define DMEM_CHUNK_NPAGES (DMEM_CHUNK_SIZE >> PAGE_SHIFT)
46 
47 struct nouveau_migrate;
48 
49 enum nouveau_aper {
50 	NOUVEAU_APER_VIRT,
51 	NOUVEAU_APER_VRAM,
52 	NOUVEAU_APER_HOST,
53 };
54 
55 typedef int (*nouveau_migrate_copy_t)(struct nouveau_drm *drm, u64 npages,
56 				      enum nouveau_aper, u64 dst_addr,
57 				      enum nouveau_aper, u64 src_addr);
58 
59 struct nouveau_dmem_chunk {
60 	struct list_head list;
61 	struct nouveau_bo *bo;
62 	struct nouveau_drm *drm;
63 	unsigned long pfn_first;
64 	unsigned long callocated;
65 	unsigned long bitmap[BITS_TO_LONGS(DMEM_CHUNK_NPAGES)];
66 	spinlock_t lock;
67 };
68 
69 struct nouveau_dmem_migrate {
70 	nouveau_migrate_copy_t copy_func;
71 	struct nouveau_channel *chan;
72 };
73 
74 struct nouveau_dmem {
75 	struct nouveau_drm *drm;
76 	struct dev_pagemap pagemap;
77 	struct nouveau_dmem_migrate migrate;
78 	struct list_head chunk_free;
79 	struct list_head chunk_full;
80 	struct list_head chunk_empty;
81 	struct mutex mutex;
82 };
83 
84 static inline struct nouveau_dmem *page_to_dmem(struct page *page)
85 {
86 	return container_of(page->pgmap, struct nouveau_dmem, pagemap);
87 }
88 
89 struct nouveau_dmem_fault {
90 	struct nouveau_drm *drm;
91 	struct nouveau_fence *fence;
92 	dma_addr_t *dma;
93 	unsigned long npages;
94 };
95 
96 struct nouveau_migrate {
97 	struct vm_area_struct *vma;
98 	struct nouveau_drm *drm;
99 	struct nouveau_fence *fence;
100 	unsigned long npages;
101 	dma_addr_t *dma;
102 	unsigned long dma_nr;
103 };
104 
105 static void nouveau_dmem_page_free(struct page *page)
106 {
107 	struct nouveau_dmem_chunk *chunk = page->zone_device_data;
108 	unsigned long idx = page_to_pfn(page) - chunk->pfn_first;
109 
110 	/*
111 	 * FIXME:
112 	 *
113 	 * This is really a bad example, we need to overhaul nouveau memory
114 	 * management to be more page focus and allow lighter locking scheme
115 	 * to be use in the process.
116 	 */
117 	spin_lock(&chunk->lock);
118 	clear_bit(idx, chunk->bitmap);
119 	WARN_ON(!chunk->callocated);
120 	chunk->callocated--;
121 	/*
122 	 * FIXME when chunk->callocated reach 0 we should add the chunk to
123 	 * a reclaim list so that it can be freed in case of memory pressure.
124 	 */
125 	spin_unlock(&chunk->lock);
126 }
127 
128 static void
129 nouveau_dmem_fault_alloc_and_copy(struct vm_area_struct *vma,
130 				  const unsigned long *src_pfns,
131 				  unsigned long *dst_pfns,
132 				  unsigned long start,
133 				  unsigned long end,
134 				  void *private)
135 {
136 	struct nouveau_dmem_fault *fault = private;
137 	struct nouveau_drm *drm = fault->drm;
138 	struct device *dev = drm->dev->dev;
139 	unsigned long addr, i, npages = 0;
140 	nouveau_migrate_copy_t copy;
141 	int ret;
142 
143 
144 	/* First allocate new memory */
145 	for (addr = start, i = 0; addr < end; addr += PAGE_SIZE, i++) {
146 		struct page *dpage, *spage;
147 
148 		dst_pfns[i] = 0;
149 		spage = migrate_pfn_to_page(src_pfns[i]);
150 		if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE))
151 			continue;
152 
153 		dpage = alloc_page_vma(GFP_HIGHUSER, vma, addr);
154 		if (!dpage) {
155 			dst_pfns[i] = MIGRATE_PFN_ERROR;
156 			continue;
157 		}
158 		lock_page(dpage);
159 
160 		dst_pfns[i] = migrate_pfn(page_to_pfn(dpage)) |
161 			      MIGRATE_PFN_LOCKED;
162 		npages++;
163 	}
164 
165 	/* Allocate storage for DMA addresses, so we can unmap later. */
166 	fault->dma = kmalloc(sizeof(*fault->dma) * npages, GFP_KERNEL);
167 	if (!fault->dma)
168 		goto error;
169 
170 	/* Copy things over */
171 	copy = drm->dmem->migrate.copy_func;
172 	for (addr = start, i = 0; addr < end; addr += PAGE_SIZE, i++) {
173 		struct nouveau_dmem_chunk *chunk;
174 		struct page *spage, *dpage;
175 		u64 src_addr, dst_addr;
176 
177 		dpage = migrate_pfn_to_page(dst_pfns[i]);
178 		if (!dpage || dst_pfns[i] == MIGRATE_PFN_ERROR)
179 			continue;
180 
181 		spage = migrate_pfn_to_page(src_pfns[i]);
182 		if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE)) {
183 			dst_pfns[i] = MIGRATE_PFN_ERROR;
184 			__free_page(dpage);
185 			continue;
186 		}
187 
188 		fault->dma[fault->npages] =
189 			dma_map_page_attrs(dev, dpage, 0, PAGE_SIZE,
190 					   PCI_DMA_BIDIRECTIONAL,
191 					   DMA_ATTR_SKIP_CPU_SYNC);
192 		if (dma_mapping_error(dev, fault->dma[fault->npages])) {
193 			dst_pfns[i] = MIGRATE_PFN_ERROR;
194 			__free_page(dpage);
195 			continue;
196 		}
197 
198 		dst_addr = fault->dma[fault->npages++];
199 
200 		chunk = spage->zone_device_data;
201 		src_addr = page_to_pfn(spage) - chunk->pfn_first;
202 		src_addr = (src_addr << PAGE_SHIFT) + chunk->bo->bo.offset;
203 
204 		ret = copy(drm, 1, NOUVEAU_APER_HOST, dst_addr,
205 				   NOUVEAU_APER_VRAM, src_addr);
206 		if (ret) {
207 			dst_pfns[i] = MIGRATE_PFN_ERROR;
208 			__free_page(dpage);
209 			continue;
210 		}
211 	}
212 
213 	nouveau_fence_new(drm->dmem->migrate.chan, false, &fault->fence);
214 
215 	return;
216 
217 error:
218 	for (addr = start, i = 0; addr < end; addr += PAGE_SIZE, ++i) {
219 		struct page *page;
220 
221 		if (!dst_pfns[i] || dst_pfns[i] == MIGRATE_PFN_ERROR)
222 			continue;
223 
224 		page = migrate_pfn_to_page(dst_pfns[i]);
225 		dst_pfns[i] = MIGRATE_PFN_ERROR;
226 		if (page == NULL)
227 			continue;
228 
229 		__free_page(page);
230 	}
231 }
232 
233 void nouveau_dmem_fault_finalize_and_map(struct vm_area_struct *vma,
234 					 const unsigned long *src_pfns,
235 					 const unsigned long *dst_pfns,
236 					 unsigned long start,
237 					 unsigned long end,
238 					 void *private)
239 {
240 	struct nouveau_dmem_fault *fault = private;
241 	struct nouveau_drm *drm = fault->drm;
242 
243 	if (fault->fence) {
244 		nouveau_fence_wait(fault->fence, true, false);
245 		nouveau_fence_unref(&fault->fence);
246 	} else {
247 		/*
248 		 * FIXME wait for channel to be IDLE before calling finalizing
249 		 * the hmem object below (nouveau_migrate_hmem_fini()).
250 		 */
251 	}
252 
253 	while (fault->npages--) {
254 		dma_unmap_page(drm->dev->dev, fault->dma[fault->npages],
255 			       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
256 	}
257 	kfree(fault->dma);
258 }
259 
260 static const struct migrate_vma_ops nouveau_dmem_fault_migrate_ops = {
261 	.alloc_and_copy		= nouveau_dmem_fault_alloc_and_copy,
262 	.finalize_and_map	= nouveau_dmem_fault_finalize_and_map,
263 };
264 
265 static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf)
266 {
267 	struct nouveau_dmem *dmem = page_to_dmem(vmf->page);
268 	unsigned long src[1] = {0}, dst[1] = {0};
269 	struct nouveau_dmem_fault fault = { .drm = dmem->drm };
270 	int ret;
271 
272 	/*
273 	 * FIXME what we really want is to find some heuristic to migrate more
274 	 * than just one page on CPU fault. When such fault happens it is very
275 	 * likely that more surrounding page will CPU fault too.
276 	 */
277 	ret = migrate_vma(&nouveau_dmem_fault_migrate_ops, vmf->vma,
278 			vmf->address, vmf->address + PAGE_SIZE,
279 			src, dst, &fault);
280 	if (ret)
281 		return VM_FAULT_SIGBUS;
282 
283 	if (dst[0] == MIGRATE_PFN_ERROR)
284 		return VM_FAULT_SIGBUS;
285 
286 	return 0;
287 }
288 
289 static const struct dev_pagemap_ops nouveau_dmem_pagemap_ops = {
290 	.page_free		= nouveau_dmem_page_free,
291 	.migrate_to_ram		= nouveau_dmem_migrate_to_ram,
292 };
293 
294 static int
295 nouveau_dmem_chunk_alloc(struct nouveau_drm *drm)
296 {
297 	struct nouveau_dmem_chunk *chunk;
298 	int ret;
299 
300 	if (drm->dmem == NULL)
301 		return -EINVAL;
302 
303 	mutex_lock(&drm->dmem->mutex);
304 	chunk = list_first_entry_or_null(&drm->dmem->chunk_empty,
305 					 struct nouveau_dmem_chunk,
306 					 list);
307 	if (chunk == NULL) {
308 		mutex_unlock(&drm->dmem->mutex);
309 		return -ENOMEM;
310 	}
311 
312 	list_del(&chunk->list);
313 	mutex_unlock(&drm->dmem->mutex);
314 
315 	ret = nouveau_bo_new(&drm->client, DMEM_CHUNK_SIZE, 0,
316 			     TTM_PL_FLAG_VRAM, 0, 0, NULL, NULL,
317 			     &chunk->bo);
318 	if (ret)
319 		goto out;
320 
321 	ret = nouveau_bo_pin(chunk->bo, TTM_PL_FLAG_VRAM, false);
322 	if (ret) {
323 		nouveau_bo_ref(NULL, &chunk->bo);
324 		goto out;
325 	}
326 
327 	bitmap_zero(chunk->bitmap, DMEM_CHUNK_NPAGES);
328 	spin_lock_init(&chunk->lock);
329 
330 out:
331 	mutex_lock(&drm->dmem->mutex);
332 	if (chunk->bo)
333 		list_add(&chunk->list, &drm->dmem->chunk_empty);
334 	else
335 		list_add_tail(&chunk->list, &drm->dmem->chunk_empty);
336 	mutex_unlock(&drm->dmem->mutex);
337 
338 	return ret;
339 }
340 
341 static struct nouveau_dmem_chunk *
342 nouveau_dmem_chunk_first_free_locked(struct nouveau_drm *drm)
343 {
344 	struct nouveau_dmem_chunk *chunk;
345 
346 	chunk = list_first_entry_or_null(&drm->dmem->chunk_free,
347 					 struct nouveau_dmem_chunk,
348 					 list);
349 	if (chunk)
350 		return chunk;
351 
352 	chunk = list_first_entry_or_null(&drm->dmem->chunk_empty,
353 					 struct nouveau_dmem_chunk,
354 					 list);
355 	if (chunk->bo)
356 		return chunk;
357 
358 	return NULL;
359 }
360 
361 static int
362 nouveau_dmem_pages_alloc(struct nouveau_drm *drm,
363 			 unsigned long npages,
364 			 unsigned long *pages)
365 {
366 	struct nouveau_dmem_chunk *chunk;
367 	unsigned long c;
368 	int ret;
369 
370 	memset(pages, 0xff, npages * sizeof(*pages));
371 
372 	mutex_lock(&drm->dmem->mutex);
373 	for (c = 0; c < npages;) {
374 		unsigned long i;
375 
376 		chunk = nouveau_dmem_chunk_first_free_locked(drm);
377 		if (chunk == NULL) {
378 			mutex_unlock(&drm->dmem->mutex);
379 			ret = nouveau_dmem_chunk_alloc(drm);
380 			if (ret) {
381 				if (c)
382 					return 0;
383 				return ret;
384 			}
385 			mutex_lock(&drm->dmem->mutex);
386 			continue;
387 		}
388 
389 		spin_lock(&chunk->lock);
390 		i = find_first_zero_bit(chunk->bitmap, DMEM_CHUNK_NPAGES);
391 		while (i < DMEM_CHUNK_NPAGES && c < npages) {
392 			pages[c] = chunk->pfn_first + i;
393 			set_bit(i, chunk->bitmap);
394 			chunk->callocated++;
395 			c++;
396 
397 			i = find_next_zero_bit(chunk->bitmap,
398 					DMEM_CHUNK_NPAGES, i);
399 		}
400 		spin_unlock(&chunk->lock);
401 	}
402 	mutex_unlock(&drm->dmem->mutex);
403 
404 	return 0;
405 }
406 
407 static struct page *
408 nouveau_dmem_page_alloc_locked(struct nouveau_drm *drm)
409 {
410 	unsigned long pfns[1];
411 	struct page *page;
412 	int ret;
413 
414 	/* FIXME stop all the miss-match API ... */
415 	ret = nouveau_dmem_pages_alloc(drm, 1, pfns);
416 	if (ret)
417 		return NULL;
418 
419 	page = pfn_to_page(pfns[0]);
420 	get_page(page);
421 	lock_page(page);
422 	return page;
423 }
424 
425 static void
426 nouveau_dmem_page_free_locked(struct nouveau_drm *drm, struct page *page)
427 {
428 	unlock_page(page);
429 	put_page(page);
430 }
431 
432 void
433 nouveau_dmem_resume(struct nouveau_drm *drm)
434 {
435 	struct nouveau_dmem_chunk *chunk;
436 	int ret;
437 
438 	if (drm->dmem == NULL)
439 		return;
440 
441 	mutex_lock(&drm->dmem->mutex);
442 	list_for_each_entry (chunk, &drm->dmem->chunk_free, list) {
443 		ret = nouveau_bo_pin(chunk->bo, TTM_PL_FLAG_VRAM, false);
444 		/* FIXME handle pin failure */
445 		WARN_ON(ret);
446 	}
447 	list_for_each_entry (chunk, &drm->dmem->chunk_full, list) {
448 		ret = nouveau_bo_pin(chunk->bo, TTM_PL_FLAG_VRAM, false);
449 		/* FIXME handle pin failure */
450 		WARN_ON(ret);
451 	}
452 	mutex_unlock(&drm->dmem->mutex);
453 }
454 
455 void
456 nouveau_dmem_suspend(struct nouveau_drm *drm)
457 {
458 	struct nouveau_dmem_chunk *chunk;
459 
460 	if (drm->dmem == NULL)
461 		return;
462 
463 	mutex_lock(&drm->dmem->mutex);
464 	list_for_each_entry (chunk, &drm->dmem->chunk_free, list) {
465 		nouveau_bo_unpin(chunk->bo);
466 	}
467 	list_for_each_entry (chunk, &drm->dmem->chunk_full, list) {
468 		nouveau_bo_unpin(chunk->bo);
469 	}
470 	mutex_unlock(&drm->dmem->mutex);
471 }
472 
473 void
474 nouveau_dmem_fini(struct nouveau_drm *drm)
475 {
476 	struct nouveau_dmem_chunk *chunk, *tmp;
477 
478 	if (drm->dmem == NULL)
479 		return;
480 
481 	mutex_lock(&drm->dmem->mutex);
482 
483 	WARN_ON(!list_empty(&drm->dmem->chunk_free));
484 	WARN_ON(!list_empty(&drm->dmem->chunk_full));
485 
486 	list_for_each_entry_safe (chunk, tmp, &drm->dmem->chunk_empty, list) {
487 		if (chunk->bo) {
488 			nouveau_bo_unpin(chunk->bo);
489 			nouveau_bo_ref(NULL, &chunk->bo);
490 		}
491 		list_del(&chunk->list);
492 		kfree(chunk);
493 	}
494 
495 	mutex_unlock(&drm->dmem->mutex);
496 }
497 
498 static int
499 nvc0b5_migrate_copy(struct nouveau_drm *drm, u64 npages,
500 		    enum nouveau_aper dst_aper, u64 dst_addr,
501 		    enum nouveau_aper src_aper, u64 src_addr)
502 {
503 	struct nouveau_channel *chan = drm->dmem->migrate.chan;
504 	u32 launch_dma = (1 << 9) /* MULTI_LINE_ENABLE. */ |
505 			 (1 << 8) /* DST_MEMORY_LAYOUT_PITCH. */ |
506 			 (1 << 7) /* SRC_MEMORY_LAYOUT_PITCH. */ |
507 			 (1 << 2) /* FLUSH_ENABLE_TRUE. */ |
508 			 (2 << 0) /* DATA_TRANSFER_TYPE_NON_PIPELINED. */;
509 	int ret;
510 
511 	ret = RING_SPACE(chan, 13);
512 	if (ret)
513 		return ret;
514 
515 	if (src_aper != NOUVEAU_APER_VIRT) {
516 		switch (src_aper) {
517 		case NOUVEAU_APER_VRAM:
518 			BEGIN_IMC0(chan, NvSubCopy, 0x0260, 0);
519 			break;
520 		case NOUVEAU_APER_HOST:
521 			BEGIN_IMC0(chan, NvSubCopy, 0x0260, 1);
522 			break;
523 		default:
524 			return -EINVAL;
525 		}
526 		launch_dma |= 0x00001000; /* SRC_TYPE_PHYSICAL. */
527 	}
528 
529 	if (dst_aper != NOUVEAU_APER_VIRT) {
530 		switch (dst_aper) {
531 		case NOUVEAU_APER_VRAM:
532 			BEGIN_IMC0(chan, NvSubCopy, 0x0264, 0);
533 			break;
534 		case NOUVEAU_APER_HOST:
535 			BEGIN_IMC0(chan, NvSubCopy, 0x0264, 1);
536 			break;
537 		default:
538 			return -EINVAL;
539 		}
540 		launch_dma |= 0x00002000; /* DST_TYPE_PHYSICAL. */
541 	}
542 
543 	BEGIN_NVC0(chan, NvSubCopy, 0x0400, 8);
544 	OUT_RING  (chan, upper_32_bits(src_addr));
545 	OUT_RING  (chan, lower_32_bits(src_addr));
546 	OUT_RING  (chan, upper_32_bits(dst_addr));
547 	OUT_RING  (chan, lower_32_bits(dst_addr));
548 	OUT_RING  (chan, PAGE_SIZE);
549 	OUT_RING  (chan, PAGE_SIZE);
550 	OUT_RING  (chan, PAGE_SIZE);
551 	OUT_RING  (chan, npages);
552 	BEGIN_NVC0(chan, NvSubCopy, 0x0300, 1);
553 	OUT_RING  (chan, launch_dma);
554 	return 0;
555 }
556 
557 static int
558 nouveau_dmem_migrate_init(struct nouveau_drm *drm)
559 {
560 	switch (drm->ttm.copy.oclass) {
561 	case PASCAL_DMA_COPY_A:
562 	case PASCAL_DMA_COPY_B:
563 	case  VOLTA_DMA_COPY_A:
564 	case TURING_DMA_COPY_A:
565 		drm->dmem->migrate.copy_func = nvc0b5_migrate_copy;
566 		drm->dmem->migrate.chan = drm->ttm.chan;
567 		return 0;
568 	default:
569 		break;
570 	}
571 	return -ENODEV;
572 }
573 
574 void
575 nouveau_dmem_init(struct nouveau_drm *drm)
576 {
577 	struct device *device = drm->dev->dev;
578 	struct resource *res;
579 	unsigned long i, size, pfn_first;
580 	int ret;
581 
582 	/* This only make sense on PASCAL or newer */
583 	if (drm->client.device.info.family < NV_DEVICE_INFO_V0_PASCAL)
584 		return;
585 
586 	if (!(drm->dmem = kzalloc(sizeof(*drm->dmem), GFP_KERNEL)))
587 		return;
588 
589 	drm->dmem->drm = drm;
590 	mutex_init(&drm->dmem->mutex);
591 	INIT_LIST_HEAD(&drm->dmem->chunk_free);
592 	INIT_LIST_HEAD(&drm->dmem->chunk_full);
593 	INIT_LIST_HEAD(&drm->dmem->chunk_empty);
594 
595 	size = ALIGN(drm->client.device.info.ram_user, DMEM_CHUNK_SIZE);
596 
597 	/* Initialize migration dma helpers before registering memory */
598 	ret = nouveau_dmem_migrate_init(drm);
599 	if (ret)
600 		goto out_free;
601 
602 	/*
603 	 * FIXME we need some kind of policy to decide how much VRAM we
604 	 * want to register with HMM. For now just register everything
605 	 * and latter if we want to do thing like over commit then we
606 	 * could revisit this.
607 	 */
608 	res = devm_request_free_mem_region(device, &iomem_resource, size);
609 	if (IS_ERR(res))
610 		goto out_free;
611 	drm->dmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
612 	drm->dmem->pagemap.res = *res;
613 	drm->dmem->pagemap.ops = &nouveau_dmem_pagemap_ops;
614 	if (IS_ERR(devm_memremap_pages(device, &drm->dmem->pagemap)))
615 		goto out_free;
616 
617 	pfn_first = res->start >> PAGE_SHIFT;
618 	for (i = 0; i < (size / DMEM_CHUNK_SIZE); ++i) {
619 		struct nouveau_dmem_chunk *chunk;
620 		struct page *page;
621 		unsigned long j;
622 
623 		chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
624 		if (chunk == NULL) {
625 			nouveau_dmem_fini(drm);
626 			return;
627 		}
628 
629 		chunk->drm = drm;
630 		chunk->pfn_first = pfn_first + (i * DMEM_CHUNK_NPAGES);
631 		list_add_tail(&chunk->list, &drm->dmem->chunk_empty);
632 
633 		page = pfn_to_page(chunk->pfn_first);
634 		for (j = 0; j < DMEM_CHUNK_NPAGES; ++j, ++page)
635 			page->zone_device_data = chunk;
636 	}
637 
638 	NV_INFO(drm, "DMEM: registered %ldMB of device memory\n", size >> 20);
639 	return;
640 out_free:
641 	kfree(drm->dmem);
642 	drm->dmem = NULL;
643 }
644 
645 static void
646 nouveau_dmem_migrate_alloc_and_copy(struct vm_area_struct *vma,
647 				    const unsigned long *src_pfns,
648 				    unsigned long *dst_pfns,
649 				    unsigned long start,
650 				    unsigned long end,
651 				    void *private)
652 {
653 	struct nouveau_migrate *migrate = private;
654 	struct nouveau_drm *drm = migrate->drm;
655 	struct device *dev = drm->dev->dev;
656 	unsigned long addr, i, npages = 0;
657 	nouveau_migrate_copy_t copy;
658 	int ret;
659 
660 	/* First allocate new memory */
661 	for (addr = start, i = 0; addr < end; addr += PAGE_SIZE, i++) {
662 		struct page *dpage, *spage;
663 
664 		dst_pfns[i] = 0;
665 		spage = migrate_pfn_to_page(src_pfns[i]);
666 		if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE))
667 			continue;
668 
669 		dpage = nouveau_dmem_page_alloc_locked(drm);
670 		if (!dpage)
671 			continue;
672 
673 		dst_pfns[i] = migrate_pfn(page_to_pfn(dpage)) |
674 			      MIGRATE_PFN_LOCKED |
675 			      MIGRATE_PFN_DEVICE;
676 		npages++;
677 	}
678 
679 	if (!npages)
680 		return;
681 
682 	/* Allocate storage for DMA addresses, so we can unmap later. */
683 	migrate->dma = kmalloc(sizeof(*migrate->dma) * npages, GFP_KERNEL);
684 	if (!migrate->dma)
685 		goto error;
686 
687 	/* Copy things over */
688 	copy = drm->dmem->migrate.copy_func;
689 	for (addr = start, i = 0; addr < end; addr += PAGE_SIZE, i++) {
690 		struct nouveau_dmem_chunk *chunk;
691 		struct page *spage, *dpage;
692 		u64 src_addr, dst_addr;
693 
694 		dpage = migrate_pfn_to_page(dst_pfns[i]);
695 		if (!dpage || dst_pfns[i] == MIGRATE_PFN_ERROR)
696 			continue;
697 
698 		chunk = dpage->zone_device_data;
699 		dst_addr = page_to_pfn(dpage) - chunk->pfn_first;
700 		dst_addr = (dst_addr << PAGE_SHIFT) + chunk->bo->bo.offset;
701 
702 		spage = migrate_pfn_to_page(src_pfns[i]);
703 		if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE)) {
704 			nouveau_dmem_page_free_locked(drm, dpage);
705 			dst_pfns[i] = 0;
706 			continue;
707 		}
708 
709 		migrate->dma[migrate->dma_nr] =
710 			dma_map_page_attrs(dev, spage, 0, PAGE_SIZE,
711 					   PCI_DMA_BIDIRECTIONAL,
712 					   DMA_ATTR_SKIP_CPU_SYNC);
713 		if (dma_mapping_error(dev, migrate->dma[migrate->dma_nr])) {
714 			nouveau_dmem_page_free_locked(drm, dpage);
715 			dst_pfns[i] = 0;
716 			continue;
717 		}
718 
719 		src_addr = migrate->dma[migrate->dma_nr++];
720 
721 		ret = copy(drm, 1, NOUVEAU_APER_VRAM, dst_addr,
722 				   NOUVEAU_APER_HOST, src_addr);
723 		if (ret) {
724 			nouveau_dmem_page_free_locked(drm, dpage);
725 			dst_pfns[i] = 0;
726 			continue;
727 		}
728 	}
729 
730 	nouveau_fence_new(drm->dmem->migrate.chan, false, &migrate->fence);
731 
732 	return;
733 
734 error:
735 	for (addr = start, i = 0; addr < end; addr += PAGE_SIZE, ++i) {
736 		struct page *page;
737 
738 		if (!dst_pfns[i] || dst_pfns[i] == MIGRATE_PFN_ERROR)
739 			continue;
740 
741 		page = migrate_pfn_to_page(dst_pfns[i]);
742 		dst_pfns[i] = MIGRATE_PFN_ERROR;
743 		if (page == NULL)
744 			continue;
745 
746 		__free_page(page);
747 	}
748 }
749 
750 void nouveau_dmem_migrate_finalize_and_map(struct vm_area_struct *vma,
751 					   const unsigned long *src_pfns,
752 					   const unsigned long *dst_pfns,
753 					   unsigned long start,
754 					   unsigned long end,
755 					   void *private)
756 {
757 	struct nouveau_migrate *migrate = private;
758 	struct nouveau_drm *drm = migrate->drm;
759 
760 	if (migrate->fence) {
761 		nouveau_fence_wait(migrate->fence, true, false);
762 		nouveau_fence_unref(&migrate->fence);
763 	} else {
764 		/*
765 		 * FIXME wait for channel to be IDLE before finalizing
766 		 * the hmem object below (nouveau_migrate_hmem_fini()) ?
767 		 */
768 	}
769 
770 	while (migrate->dma_nr--) {
771 		dma_unmap_page(drm->dev->dev, migrate->dma[migrate->dma_nr],
772 			       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
773 	}
774 	kfree(migrate->dma);
775 
776 	/*
777 	 * FIXME optimization: update GPU page table to point to newly
778 	 * migrated memory.
779 	 */
780 }
781 
782 static const struct migrate_vma_ops nouveau_dmem_migrate_ops = {
783 	.alloc_and_copy		= nouveau_dmem_migrate_alloc_and_copy,
784 	.finalize_and_map	= nouveau_dmem_migrate_finalize_and_map,
785 };
786 
787 int
788 nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
789 			 struct vm_area_struct *vma,
790 			 unsigned long start,
791 			 unsigned long end)
792 {
793 	unsigned long *src_pfns, *dst_pfns, npages;
794 	struct nouveau_migrate migrate = {0};
795 	unsigned long i, c, max;
796 	int ret = 0;
797 
798 	npages = (end - start) >> PAGE_SHIFT;
799 	max = min(SG_MAX_SINGLE_ALLOC, npages);
800 	src_pfns = kzalloc(sizeof(long) * max, GFP_KERNEL);
801 	if (src_pfns == NULL)
802 		return -ENOMEM;
803 	dst_pfns = kzalloc(sizeof(long) * max, GFP_KERNEL);
804 	if (dst_pfns == NULL) {
805 		kfree(src_pfns);
806 		return -ENOMEM;
807 	}
808 
809 	migrate.drm = drm;
810 	migrate.vma = vma;
811 	migrate.npages = npages;
812 	for (i = 0; i < npages; i += c) {
813 		unsigned long next;
814 
815 		c = min(SG_MAX_SINGLE_ALLOC, npages);
816 		next = start + (c << PAGE_SHIFT);
817 		ret = migrate_vma(&nouveau_dmem_migrate_ops, vma, start,
818 				  next, src_pfns, dst_pfns, &migrate);
819 		if (ret)
820 			goto out;
821 		start = next;
822 	}
823 
824 out:
825 	kfree(dst_pfns);
826 	kfree(src_pfns);
827 	return ret;
828 }
829 
830 static inline bool
831 nouveau_dmem_page(struct nouveau_drm *drm, struct page *page)
832 {
833 	return is_device_private_page(page) && drm->dmem == page_to_dmem(page);
834 }
835 
836 void
837 nouveau_dmem_convert_pfn(struct nouveau_drm *drm,
838 			 struct hmm_range *range)
839 {
840 	unsigned long i, npages;
841 
842 	npages = (range->end - range->start) >> PAGE_SHIFT;
843 	for (i = 0; i < npages; ++i) {
844 		struct nouveau_dmem_chunk *chunk;
845 		struct page *page;
846 		uint64_t addr;
847 
848 		page = hmm_pfn_to_page(range, range->pfns[i]);
849 		if (page == NULL)
850 			continue;
851 
852 		if (!(range->pfns[i] & range->flags[HMM_PFN_DEVICE_PRIVATE])) {
853 			continue;
854 		}
855 
856 		if (!nouveau_dmem_page(drm, page)) {
857 			WARN(1, "Some unknown device memory !\n");
858 			range->pfns[i] = 0;
859 			continue;
860 		}
861 
862 		chunk = page->zone_device_data;
863 		addr = page_to_pfn(page) - chunk->pfn_first;
864 		addr = (addr + chunk->bo->bo.mem.start) << PAGE_SHIFT;
865 
866 		range->pfns[i] &= ((1UL << range->pfn_shift) - 1);
867 		range->pfns[i] |= (addr >> PAGE_SHIFT) << range->pfn_shift;
868 	}
869 }
870