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 #include "nouveau_svm.h"
29 
30 #include <nvif/class.h>
31 #include <nvif/object.h>
32 #include <nvif/push906f.h>
33 #include <nvif/if000c.h>
34 #include <nvif/if500b.h>
35 #include <nvif/if900b.h>
36 #include <nvif/if000c.h>
37 
38 #include <nvhw/class/cla0b5.h>
39 
40 #include <linux/sched/mm.h>
41 #include <linux/hmm.h>
42 
43 /*
44  * FIXME: this is ugly right now we are using TTM to allocate vram and we pin
45  * it in vram while in use. We likely want to overhaul memory management for
46  * nouveau to be more page like (not necessarily with system page size but a
47  * bigger page size) at lowest level and have some shim layer on top that would
48  * provide the same functionality as TTM.
49  */
50 #define DMEM_CHUNK_SIZE (2UL << 20)
51 #define DMEM_CHUNK_NPAGES (DMEM_CHUNK_SIZE >> PAGE_SHIFT)
52 
53 enum nouveau_aper {
54 	NOUVEAU_APER_VIRT,
55 	NOUVEAU_APER_VRAM,
56 	NOUVEAU_APER_HOST,
57 };
58 
59 typedef int (*nouveau_migrate_copy_t)(struct nouveau_drm *drm, u64 npages,
60 				      enum nouveau_aper, u64 dst_addr,
61 				      enum nouveau_aper, u64 src_addr);
62 typedef int (*nouveau_clear_page_t)(struct nouveau_drm *drm, u32 length,
63 				      enum nouveau_aper, u64 dst_addr);
64 
65 struct nouveau_dmem_chunk {
66 	struct list_head list;
67 	struct nouveau_bo *bo;
68 	struct nouveau_drm *drm;
69 	unsigned long callocated;
70 	struct dev_pagemap pagemap;
71 };
72 
73 struct nouveau_dmem_migrate {
74 	nouveau_migrate_copy_t copy_func;
75 	nouveau_clear_page_t clear_func;
76 	struct nouveau_channel *chan;
77 };
78 
79 struct nouveau_dmem {
80 	struct nouveau_drm *drm;
81 	struct nouveau_dmem_migrate migrate;
82 	struct list_head chunks;
83 	struct mutex mutex;
84 	struct page *free_pages;
85 	spinlock_t lock;
86 };
87 
88 static struct nouveau_dmem_chunk *nouveau_page_to_chunk(struct page *page)
89 {
90 	return container_of(page->pgmap, struct nouveau_dmem_chunk, pagemap);
91 }
92 
93 static struct nouveau_drm *page_to_drm(struct page *page)
94 {
95 	struct nouveau_dmem_chunk *chunk = nouveau_page_to_chunk(page);
96 
97 	return chunk->drm;
98 }
99 
100 unsigned long nouveau_dmem_page_addr(struct page *page)
101 {
102 	struct nouveau_dmem_chunk *chunk = nouveau_page_to_chunk(page);
103 	unsigned long off = (page_to_pfn(page) << PAGE_SHIFT) -
104 				chunk->pagemap.res.start;
105 
106 	return chunk->bo->offset + off;
107 }
108 
109 static void nouveau_dmem_page_free(struct page *page)
110 {
111 	struct nouveau_dmem_chunk *chunk = nouveau_page_to_chunk(page);
112 	struct nouveau_dmem *dmem = chunk->drm->dmem;
113 
114 	spin_lock(&dmem->lock);
115 	page->zone_device_data = dmem->free_pages;
116 	dmem->free_pages = page;
117 
118 	WARN_ON(!chunk->callocated);
119 	chunk->callocated--;
120 	/*
121 	 * FIXME when chunk->callocated reach 0 we should add the chunk to
122 	 * a reclaim list so that it can be freed in case of memory pressure.
123 	 */
124 	spin_unlock(&dmem->lock);
125 }
126 
127 static void nouveau_dmem_fence_done(struct nouveau_fence **fence)
128 {
129 	if (fence) {
130 		nouveau_fence_wait(*fence, true, false);
131 		nouveau_fence_unref(fence);
132 	} else {
133 		/*
134 		 * FIXME wait for channel to be IDLE before calling finalizing
135 		 * the hmem object.
136 		 */
137 	}
138 }
139 
140 static vm_fault_t nouveau_dmem_fault_copy_one(struct nouveau_drm *drm,
141 		struct vm_fault *vmf, struct migrate_vma *args,
142 		dma_addr_t *dma_addr)
143 {
144 	struct device *dev = drm->dev->dev;
145 	struct page *dpage, *spage;
146 
147 	spage = migrate_pfn_to_page(args->src[0]);
148 	if (!spage || !(args->src[0] & MIGRATE_PFN_MIGRATE))
149 		return 0;
150 
151 	dpage = alloc_page_vma(GFP_HIGHUSER, vmf->vma, vmf->address);
152 	if (!dpage)
153 		return VM_FAULT_SIGBUS;
154 	lock_page(dpage);
155 
156 	*dma_addr = dma_map_page(dev, dpage, 0, PAGE_SIZE, DMA_BIDIRECTIONAL);
157 	if (dma_mapping_error(dev, *dma_addr))
158 		goto error_free_page;
159 
160 	if (drm->dmem->migrate.copy_func(drm, 1, NOUVEAU_APER_HOST, *dma_addr,
161 			NOUVEAU_APER_VRAM, nouveau_dmem_page_addr(spage)))
162 		goto error_dma_unmap;
163 
164 	args->dst[0] = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
165 	return 0;
166 
167 error_dma_unmap:
168 	dma_unmap_page(dev, *dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);
169 error_free_page:
170 	__free_page(dpage);
171 	return VM_FAULT_SIGBUS;
172 }
173 
174 static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf)
175 {
176 	struct nouveau_drm *drm = page_to_drm(vmf->page);
177 	struct nouveau_dmem *dmem = drm->dmem;
178 	struct nouveau_fence *fence;
179 	unsigned long src = 0, dst = 0;
180 	dma_addr_t dma_addr = 0;
181 	vm_fault_t ret;
182 	struct migrate_vma args = {
183 		.vma		= vmf->vma,
184 		.start		= vmf->address,
185 		.end		= vmf->address + PAGE_SIZE,
186 		.src		= &src,
187 		.dst		= &dst,
188 		.src_owner	= drm->dev,
189 	};
190 
191 	/*
192 	 * FIXME what we really want is to find some heuristic to migrate more
193 	 * than just one page on CPU fault. When such fault happens it is very
194 	 * likely that more surrounding page will CPU fault too.
195 	 */
196 	if (migrate_vma_setup(&args) < 0)
197 		return VM_FAULT_SIGBUS;
198 	if (!args.cpages)
199 		return 0;
200 
201 	ret = nouveau_dmem_fault_copy_one(drm, vmf, &args, &dma_addr);
202 	if (ret || dst == 0)
203 		goto done;
204 
205 	nouveau_fence_new(dmem->migrate.chan, false, &fence);
206 	migrate_vma_pages(&args);
207 	nouveau_dmem_fence_done(&fence);
208 	dma_unmap_page(drm->dev->dev, dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);
209 done:
210 	migrate_vma_finalize(&args);
211 	return ret;
212 }
213 
214 static const struct dev_pagemap_ops nouveau_dmem_pagemap_ops = {
215 	.page_free		= nouveau_dmem_page_free,
216 	.migrate_to_ram		= nouveau_dmem_migrate_to_ram,
217 };
218 
219 static int
220 nouveau_dmem_chunk_alloc(struct nouveau_drm *drm, struct page **ppage)
221 {
222 	struct nouveau_dmem_chunk *chunk;
223 	struct resource *res;
224 	struct page *page;
225 	void *ptr;
226 	unsigned long i, pfn_first;
227 	int ret;
228 
229 	chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
230 	if (chunk == NULL) {
231 		ret = -ENOMEM;
232 		goto out;
233 	}
234 
235 	/* Allocate unused physical address space for device private pages. */
236 	res = request_free_mem_region(&iomem_resource, DMEM_CHUNK_SIZE,
237 				      "nouveau_dmem");
238 	if (IS_ERR(res)) {
239 		ret = PTR_ERR(res);
240 		goto out_free;
241 	}
242 
243 	chunk->drm = drm;
244 	chunk->pagemap.type = MEMORY_DEVICE_PRIVATE;
245 	chunk->pagemap.res = *res;
246 	chunk->pagemap.ops = &nouveau_dmem_pagemap_ops;
247 	chunk->pagemap.owner = drm->dev;
248 
249 	ret = nouveau_bo_new(&drm->client, DMEM_CHUNK_SIZE, 0,
250 			     TTM_PL_FLAG_VRAM, 0, 0, NULL, NULL,
251 			     &chunk->bo);
252 	if (ret)
253 		goto out_release;
254 
255 	ret = nouveau_bo_pin(chunk->bo, TTM_PL_FLAG_VRAM, false);
256 	if (ret)
257 		goto out_bo_free;
258 
259 	ptr = memremap_pages(&chunk->pagemap, numa_node_id());
260 	if (IS_ERR(ptr)) {
261 		ret = PTR_ERR(ptr);
262 		goto out_bo_unpin;
263 	}
264 
265 	mutex_lock(&drm->dmem->mutex);
266 	list_add(&chunk->list, &drm->dmem->chunks);
267 	mutex_unlock(&drm->dmem->mutex);
268 
269 	pfn_first = chunk->pagemap.res.start >> PAGE_SHIFT;
270 	page = pfn_to_page(pfn_first);
271 	spin_lock(&drm->dmem->lock);
272 	for (i = 0; i < DMEM_CHUNK_NPAGES - 1; ++i, ++page) {
273 		page->zone_device_data = drm->dmem->free_pages;
274 		drm->dmem->free_pages = page;
275 	}
276 	*ppage = page;
277 	chunk->callocated++;
278 	spin_unlock(&drm->dmem->lock);
279 
280 	NV_INFO(drm, "DMEM: registered %ldMB of device memory\n",
281 		DMEM_CHUNK_SIZE >> 20);
282 
283 	return 0;
284 
285 out_bo_unpin:
286 	nouveau_bo_unpin(chunk->bo);
287 out_bo_free:
288 	nouveau_bo_ref(NULL, &chunk->bo);
289 out_release:
290 	release_mem_region(chunk->pagemap.res.start,
291 			   resource_size(&chunk->pagemap.res));
292 out_free:
293 	kfree(chunk);
294 out:
295 	return ret;
296 }
297 
298 static struct page *
299 nouveau_dmem_page_alloc_locked(struct nouveau_drm *drm)
300 {
301 	struct nouveau_dmem_chunk *chunk;
302 	struct page *page = NULL;
303 	int ret;
304 
305 	spin_lock(&drm->dmem->lock);
306 	if (drm->dmem->free_pages) {
307 		page = drm->dmem->free_pages;
308 		drm->dmem->free_pages = page->zone_device_data;
309 		chunk = nouveau_page_to_chunk(page);
310 		chunk->callocated++;
311 		spin_unlock(&drm->dmem->lock);
312 	} else {
313 		spin_unlock(&drm->dmem->lock);
314 		ret = nouveau_dmem_chunk_alloc(drm, &page);
315 		if (ret)
316 			return NULL;
317 	}
318 
319 	get_page(page);
320 	lock_page(page);
321 	return page;
322 }
323 
324 static void
325 nouveau_dmem_page_free_locked(struct nouveau_drm *drm, struct page *page)
326 {
327 	unlock_page(page);
328 	put_page(page);
329 }
330 
331 void
332 nouveau_dmem_resume(struct nouveau_drm *drm)
333 {
334 	struct nouveau_dmem_chunk *chunk;
335 	int ret;
336 
337 	if (drm->dmem == NULL)
338 		return;
339 
340 	mutex_lock(&drm->dmem->mutex);
341 	list_for_each_entry(chunk, &drm->dmem->chunks, list) {
342 		ret = nouveau_bo_pin(chunk->bo, TTM_PL_FLAG_VRAM, false);
343 		/* FIXME handle pin failure */
344 		WARN_ON(ret);
345 	}
346 	mutex_unlock(&drm->dmem->mutex);
347 }
348 
349 void
350 nouveau_dmem_suspend(struct nouveau_drm *drm)
351 {
352 	struct nouveau_dmem_chunk *chunk;
353 
354 	if (drm->dmem == NULL)
355 		return;
356 
357 	mutex_lock(&drm->dmem->mutex);
358 	list_for_each_entry(chunk, &drm->dmem->chunks, list)
359 		nouveau_bo_unpin(chunk->bo);
360 	mutex_unlock(&drm->dmem->mutex);
361 }
362 
363 void
364 nouveau_dmem_fini(struct nouveau_drm *drm)
365 {
366 	struct nouveau_dmem_chunk *chunk, *tmp;
367 
368 	if (drm->dmem == NULL)
369 		return;
370 
371 	mutex_lock(&drm->dmem->mutex);
372 
373 	list_for_each_entry_safe(chunk, tmp, &drm->dmem->chunks, list) {
374 		nouveau_bo_unpin(chunk->bo);
375 		nouveau_bo_ref(NULL, &chunk->bo);
376 		list_del(&chunk->list);
377 		memunmap_pages(&chunk->pagemap);
378 		release_mem_region(chunk->pagemap.res.start,
379 				   resource_size(&chunk->pagemap.res));
380 		kfree(chunk);
381 	}
382 
383 	mutex_unlock(&drm->dmem->mutex);
384 }
385 
386 static int
387 nvc0b5_migrate_copy(struct nouveau_drm *drm, u64 npages,
388 		    enum nouveau_aper dst_aper, u64 dst_addr,
389 		    enum nouveau_aper src_aper, u64 src_addr)
390 {
391 	struct nvif_push *push = drm->dmem->migrate.chan->chan.push;
392 	u32 launch_dma = 0;
393 	int ret;
394 
395 	ret = PUSH_WAIT(push, 13);
396 	if (ret)
397 		return ret;
398 
399 	if (src_aper != NOUVEAU_APER_VIRT) {
400 		switch (src_aper) {
401 		case NOUVEAU_APER_VRAM:
402 			PUSH_IMMD(push, NVA0B5, SET_SRC_PHYS_MODE,
403 				  NVDEF(NVA0B5, SET_SRC_PHYS_MODE, TARGET, LOCAL_FB));
404 			break;
405 		case NOUVEAU_APER_HOST:
406 			PUSH_IMMD(push, NVA0B5, SET_SRC_PHYS_MODE,
407 				  NVDEF(NVA0B5, SET_SRC_PHYS_MODE, TARGET, COHERENT_SYSMEM));
408 			break;
409 		default:
410 			return -EINVAL;
411 		}
412 
413 		launch_dma |= NVDEF(NVA0B5, LAUNCH_DMA, SRC_TYPE, PHYSICAL);
414 	}
415 
416 	if (dst_aper != NOUVEAU_APER_VIRT) {
417 		switch (dst_aper) {
418 		case NOUVEAU_APER_VRAM:
419 			PUSH_IMMD(push, NVA0B5, SET_DST_PHYS_MODE,
420 				  NVDEF(NVA0B5, SET_DST_PHYS_MODE, TARGET, LOCAL_FB));
421 			break;
422 		case NOUVEAU_APER_HOST:
423 			PUSH_IMMD(push, NVA0B5, SET_DST_PHYS_MODE,
424 				  NVDEF(NVA0B5, SET_DST_PHYS_MODE, TARGET, COHERENT_SYSMEM));
425 			break;
426 		default:
427 			return -EINVAL;
428 		}
429 
430 		launch_dma |= NVDEF(NVA0B5, LAUNCH_DMA, DST_TYPE, PHYSICAL);
431 	}
432 
433 	PUSH_MTHD(push, NVA0B5, OFFSET_IN_UPPER,
434 		  NVVAL(NVA0B5, OFFSET_IN_UPPER, UPPER, upper_32_bits(src_addr)),
435 
436 				OFFSET_IN_LOWER, lower_32_bits(src_addr),
437 
438 				OFFSET_OUT_UPPER,
439 		  NVVAL(NVA0B5, OFFSET_OUT_UPPER, UPPER, upper_32_bits(dst_addr)),
440 
441 				OFFSET_OUT_LOWER, lower_32_bits(dst_addr),
442 				PITCH_IN, PAGE_SIZE,
443 				PITCH_OUT, PAGE_SIZE,
444 				LINE_LENGTH_IN, PAGE_SIZE,
445 				LINE_COUNT, npages);
446 
447 	PUSH_MTHD(push, NVA0B5, LAUNCH_DMA, launch_dma |
448 		  NVDEF(NVA0B5, LAUNCH_DMA, DATA_TRANSFER_TYPE, NON_PIPELINED) |
449 		  NVDEF(NVA0B5, LAUNCH_DMA, FLUSH_ENABLE, TRUE) |
450 		  NVDEF(NVA0B5, LAUNCH_DMA, SEMAPHORE_TYPE, NONE) |
451 		  NVDEF(NVA0B5, LAUNCH_DMA, INTERRUPT_TYPE, NONE) |
452 		  NVDEF(NVA0B5, LAUNCH_DMA, SRC_MEMORY_LAYOUT, PITCH) |
453 		  NVDEF(NVA0B5, LAUNCH_DMA, DST_MEMORY_LAYOUT, PITCH) |
454 		  NVDEF(NVA0B5, LAUNCH_DMA, MULTI_LINE_ENABLE, TRUE) |
455 		  NVDEF(NVA0B5, LAUNCH_DMA, REMAP_ENABLE, FALSE) |
456 		  NVDEF(NVA0B5, LAUNCH_DMA, BYPASS_L2, USE_PTE_SETTING));
457 	return 0;
458 }
459 
460 static int
461 nvc0b5_migrate_clear(struct nouveau_drm *drm, u32 length,
462 		     enum nouveau_aper dst_aper, u64 dst_addr)
463 {
464 	struct nvif_push *push = drm->dmem->migrate.chan->chan.push;
465 	u32 launch_dma = 0;
466 	int ret;
467 
468 	ret = PUSH_WAIT(push, 12);
469 	if (ret)
470 		return ret;
471 
472 	switch (dst_aper) {
473 	case NOUVEAU_APER_VRAM:
474 		PUSH_IMMD(push, NVA0B5, SET_DST_PHYS_MODE,
475 			  NVDEF(NVA0B5, SET_DST_PHYS_MODE, TARGET, LOCAL_FB));
476 		break;
477 	case NOUVEAU_APER_HOST:
478 		PUSH_IMMD(push, NVA0B5, SET_DST_PHYS_MODE,
479 			  NVDEF(NVA0B5, SET_DST_PHYS_MODE, TARGET, COHERENT_SYSMEM));
480 		break;
481 	default:
482 		return -EINVAL;
483 	}
484 
485 	launch_dma |= NVDEF(NVA0B5, LAUNCH_DMA, DST_TYPE, PHYSICAL);
486 
487 	PUSH_MTHD(push, NVA0B5, SET_REMAP_CONST_A, 0,
488 				SET_REMAP_CONST_B, 0,
489 
490 				SET_REMAP_COMPONENTS,
491 		  NVDEF(NVA0B5, SET_REMAP_COMPONENTS, DST_X, CONST_A) |
492 		  NVDEF(NVA0B5, SET_REMAP_COMPONENTS, DST_Y, CONST_B) |
493 		  NVDEF(NVA0B5, SET_REMAP_COMPONENTS, COMPONENT_SIZE, FOUR) |
494 		  NVDEF(NVA0B5, SET_REMAP_COMPONENTS, NUM_DST_COMPONENTS, TWO));
495 
496 	PUSH_MTHD(push, NVA0B5, OFFSET_OUT_UPPER,
497 		  NVVAL(NVA0B5, OFFSET_OUT_UPPER, UPPER, upper_32_bits(dst_addr)),
498 
499 				OFFSET_OUT_LOWER, lower_32_bits(dst_addr));
500 
501 	PUSH_MTHD(push, NVA0B5, LINE_LENGTH_IN, length >> 3);
502 
503 	PUSH_MTHD(push, NVA0B5, LAUNCH_DMA, launch_dma |
504 		  NVDEF(NVA0B5, LAUNCH_DMA, DATA_TRANSFER_TYPE, NON_PIPELINED) |
505 		  NVDEF(NVA0B5, LAUNCH_DMA, FLUSH_ENABLE, TRUE) |
506 		  NVDEF(NVA0B5, LAUNCH_DMA, SEMAPHORE_TYPE, NONE) |
507 		  NVDEF(NVA0B5, LAUNCH_DMA, INTERRUPT_TYPE, NONE) |
508 		  NVDEF(NVA0B5, LAUNCH_DMA, SRC_MEMORY_LAYOUT, PITCH) |
509 		  NVDEF(NVA0B5, LAUNCH_DMA, DST_MEMORY_LAYOUT, PITCH) |
510 		  NVDEF(NVA0B5, LAUNCH_DMA, MULTI_LINE_ENABLE, FALSE) |
511 		  NVDEF(NVA0B5, LAUNCH_DMA, REMAP_ENABLE, TRUE) |
512 		  NVDEF(NVA0B5, LAUNCH_DMA, BYPASS_L2, USE_PTE_SETTING));
513 	return 0;
514 }
515 
516 static int
517 nouveau_dmem_migrate_init(struct nouveau_drm *drm)
518 {
519 	switch (drm->ttm.copy.oclass) {
520 	case PASCAL_DMA_COPY_A:
521 	case PASCAL_DMA_COPY_B:
522 	case  VOLTA_DMA_COPY_A:
523 	case TURING_DMA_COPY_A:
524 		drm->dmem->migrate.copy_func = nvc0b5_migrate_copy;
525 		drm->dmem->migrate.clear_func = nvc0b5_migrate_clear;
526 		drm->dmem->migrate.chan = drm->ttm.chan;
527 		return 0;
528 	default:
529 		break;
530 	}
531 	return -ENODEV;
532 }
533 
534 void
535 nouveau_dmem_init(struct nouveau_drm *drm)
536 {
537 	int ret;
538 
539 	/* This only make sense on PASCAL or newer */
540 	if (drm->client.device.info.family < NV_DEVICE_INFO_V0_PASCAL)
541 		return;
542 
543 	if (!(drm->dmem = kzalloc(sizeof(*drm->dmem), GFP_KERNEL)))
544 		return;
545 
546 	drm->dmem->drm = drm;
547 	mutex_init(&drm->dmem->mutex);
548 	INIT_LIST_HEAD(&drm->dmem->chunks);
549 	mutex_init(&drm->dmem->mutex);
550 	spin_lock_init(&drm->dmem->lock);
551 
552 	/* Initialize migration dma helpers before registering memory */
553 	ret = nouveau_dmem_migrate_init(drm);
554 	if (ret) {
555 		kfree(drm->dmem);
556 		drm->dmem = NULL;
557 	}
558 }
559 
560 static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm,
561 		unsigned long src, dma_addr_t *dma_addr, u64 *pfn)
562 {
563 	struct device *dev = drm->dev->dev;
564 	struct page *dpage, *spage;
565 	unsigned long paddr;
566 
567 	spage = migrate_pfn_to_page(src);
568 	if (!(src & MIGRATE_PFN_MIGRATE))
569 		goto out;
570 
571 	dpage = nouveau_dmem_page_alloc_locked(drm);
572 	if (!dpage)
573 		goto out;
574 
575 	paddr = nouveau_dmem_page_addr(dpage);
576 	if (spage) {
577 		*dma_addr = dma_map_page(dev, spage, 0, page_size(spage),
578 					 DMA_BIDIRECTIONAL);
579 		if (dma_mapping_error(dev, *dma_addr))
580 			goto out_free_page;
581 		if (drm->dmem->migrate.copy_func(drm, 1,
582 			NOUVEAU_APER_VRAM, paddr, NOUVEAU_APER_HOST, *dma_addr))
583 			goto out_dma_unmap;
584 	} else {
585 		*dma_addr = DMA_MAPPING_ERROR;
586 		if (drm->dmem->migrate.clear_func(drm, page_size(dpage),
587 			NOUVEAU_APER_VRAM, paddr))
588 			goto out_free_page;
589 	}
590 
591 	*pfn = NVIF_VMM_PFNMAP_V0_V | NVIF_VMM_PFNMAP_V0_VRAM |
592 		((paddr >> PAGE_SHIFT) << NVIF_VMM_PFNMAP_V0_ADDR_SHIFT);
593 	if (src & MIGRATE_PFN_WRITE)
594 		*pfn |= NVIF_VMM_PFNMAP_V0_W;
595 	return migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
596 
597 out_dma_unmap:
598 	dma_unmap_page(dev, *dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);
599 out_free_page:
600 	nouveau_dmem_page_free_locked(drm, dpage);
601 out:
602 	*pfn = NVIF_VMM_PFNMAP_V0_NONE;
603 	return 0;
604 }
605 
606 static void nouveau_dmem_migrate_chunk(struct nouveau_drm *drm,
607 		struct nouveau_svmm *svmm, struct migrate_vma *args,
608 		dma_addr_t *dma_addrs, u64 *pfns)
609 {
610 	struct nouveau_fence *fence;
611 	unsigned long addr = args->start, nr_dma = 0, i;
612 
613 	for (i = 0; addr < args->end; i++) {
614 		args->dst[i] = nouveau_dmem_migrate_copy_one(drm, args->src[i],
615 				dma_addrs + nr_dma, pfns + i);
616 		if (!dma_mapping_error(drm->dev->dev, dma_addrs[nr_dma]))
617 			nr_dma++;
618 		addr += PAGE_SIZE;
619 	}
620 
621 	nouveau_fence_new(drm->dmem->migrate.chan, false, &fence);
622 	migrate_vma_pages(args);
623 	nouveau_dmem_fence_done(&fence);
624 	nouveau_pfns_map(svmm, args->vma->vm_mm, args->start, pfns, i);
625 
626 	while (nr_dma--) {
627 		dma_unmap_page(drm->dev->dev, dma_addrs[nr_dma], PAGE_SIZE,
628 				DMA_BIDIRECTIONAL);
629 	}
630 	migrate_vma_finalize(args);
631 }
632 
633 int
634 nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
635 			 struct nouveau_svmm *svmm,
636 			 struct vm_area_struct *vma,
637 			 unsigned long start,
638 			 unsigned long end)
639 {
640 	unsigned long npages = (end - start) >> PAGE_SHIFT;
641 	unsigned long max = min(SG_MAX_SINGLE_ALLOC, npages);
642 	dma_addr_t *dma_addrs;
643 	struct migrate_vma args = {
644 		.vma		= vma,
645 		.start		= start,
646 	};
647 	unsigned long i;
648 	u64 *pfns;
649 	int ret = -ENOMEM;
650 
651 	if (drm->dmem == NULL)
652 		return -ENODEV;
653 
654 	args.src = kcalloc(max, sizeof(*args.src), GFP_KERNEL);
655 	if (!args.src)
656 		goto out;
657 	args.dst = kcalloc(max, sizeof(*args.dst), GFP_KERNEL);
658 	if (!args.dst)
659 		goto out_free_src;
660 
661 	dma_addrs = kmalloc_array(max, sizeof(*dma_addrs), GFP_KERNEL);
662 	if (!dma_addrs)
663 		goto out_free_dst;
664 
665 	pfns = nouveau_pfns_alloc(max);
666 	if (!pfns)
667 		goto out_free_dma;
668 
669 	for (i = 0; i < npages; i += max) {
670 		args.end = start + (max << PAGE_SHIFT);
671 		ret = migrate_vma_setup(&args);
672 		if (ret)
673 			goto out_free_pfns;
674 
675 		if (args.cpages)
676 			nouveau_dmem_migrate_chunk(drm, svmm, &args, dma_addrs,
677 						   pfns);
678 		args.start = args.end;
679 	}
680 
681 	ret = 0;
682 out_free_pfns:
683 	nouveau_pfns_free(pfns);
684 out_free_dma:
685 	kfree(dma_addrs);
686 out_free_dst:
687 	kfree(args.dst);
688 out_free_src:
689 	kfree(args.src);
690 out:
691 	return ret;
692 }
693