1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2 /*
3  * Copyright 2020-2021 Advanced Micro Devices, Inc.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be included in
13  * all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21  * OTHER DEALINGS IN THE SOFTWARE.
22  */
23 
24 #include <linux/types.h>
25 #include <linux/hmm.h>
26 #include <linux/dma-direction.h>
27 #include <linux/dma-mapping.h>
28 #include "amdgpu_sync.h"
29 #include "amdgpu_object.h"
30 #include "amdgpu_vm.h"
31 #include "amdgpu_mn.h"
32 #include "amdgpu_res_cursor.h"
33 #include "kfd_priv.h"
34 #include "kfd_svm.h"
35 #include "kfd_migrate.h"
36 
37 static uint64_t
38 svm_migrate_direct_mapping_addr(struct amdgpu_device *adev, uint64_t addr)
39 {
40 	return addr + amdgpu_ttm_domain_start(adev, TTM_PL_VRAM);
41 }
42 
43 static int
44 svm_migrate_gart_map(struct amdgpu_ring *ring, uint64_t npages,
45 		     dma_addr_t *addr, uint64_t *gart_addr, uint64_t flags)
46 {
47 	struct amdgpu_device *adev = ring->adev;
48 	struct amdgpu_job *job;
49 	unsigned int num_dw, num_bytes;
50 	struct dma_fence *fence;
51 	uint64_t src_addr, dst_addr;
52 	uint64_t pte_flags;
53 	void *cpu_addr;
54 	int r;
55 
56 	/* use gart window 0 */
57 	*gart_addr = adev->gmc.gart_start;
58 
59 	num_dw = ALIGN(adev->mman.buffer_funcs->copy_num_dw, 8);
60 	num_bytes = npages * 8;
61 
62 	r = amdgpu_job_alloc_with_ib(adev, num_dw * 4 + num_bytes,
63 				     AMDGPU_IB_POOL_DELAYED, &job);
64 	if (r)
65 		return r;
66 
67 	src_addr = num_dw * 4;
68 	src_addr += job->ibs[0].gpu_addr;
69 
70 	dst_addr = amdgpu_bo_gpu_offset(adev->gart.bo);
71 	amdgpu_emit_copy_buffer(adev, &job->ibs[0], src_addr,
72 				dst_addr, num_bytes, false);
73 
74 	amdgpu_ring_pad_ib(ring, &job->ibs[0]);
75 	WARN_ON(job->ibs[0].length_dw > num_dw);
76 
77 	pte_flags = AMDGPU_PTE_VALID | AMDGPU_PTE_READABLE;
78 	pte_flags |= AMDGPU_PTE_SYSTEM | AMDGPU_PTE_SNOOPED;
79 	if (!(flags & KFD_IOCTL_SVM_FLAG_GPU_RO))
80 		pte_flags |= AMDGPU_PTE_WRITEABLE;
81 	pte_flags |= adev->gart.gart_pte_flags;
82 
83 	cpu_addr = &job->ibs[0].ptr[num_dw];
84 
85 	r = amdgpu_gart_map(adev, 0, npages, addr, pte_flags, cpu_addr);
86 	if (r)
87 		goto error_free;
88 
89 	r = amdgpu_job_submit(job, &adev->mman.entity,
90 			      AMDGPU_FENCE_OWNER_UNDEFINED, &fence);
91 	if (r)
92 		goto error_free;
93 
94 	dma_fence_put(fence);
95 
96 	return r;
97 
98 error_free:
99 	amdgpu_job_free(job);
100 	return r;
101 }
102 
103 /**
104  * svm_migrate_copy_memory_gart - sdma copy data between ram and vram
105  *
106  * @adev: amdgpu device the sdma ring running
107  * @src: source page address array
108  * @dst: destination page address array
109  * @npages: number of pages to copy
110  * @direction: enum MIGRATION_COPY_DIR
111  * @mfence: output, sdma fence to signal after sdma is done
112  *
113  * ram address uses GART table continuous entries mapping to ram pages,
114  * vram address uses direct mapping of vram pages, which must have npages
115  * number of continuous pages.
116  * GART update and sdma uses same buf copy function ring, sdma is splited to
117  * multiple GTT_MAX_PAGES transfer, all sdma operations are serialized, wait for
118  * the last sdma finish fence which is returned to check copy memory is done.
119  *
120  * Context: Process context, takes and releases gtt_window_lock
121  *
122  * Return:
123  * 0 - OK, otherwise error code
124  */
125 
126 static int
127 svm_migrate_copy_memory_gart(struct amdgpu_device *adev, dma_addr_t *sys,
128 			     uint64_t *vram, uint64_t npages,
129 			     enum MIGRATION_COPY_DIR direction,
130 			     struct dma_fence **mfence)
131 {
132 	const uint64_t GTT_MAX_PAGES = AMDGPU_GTT_MAX_TRANSFER_SIZE;
133 	struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
134 	uint64_t gart_s, gart_d;
135 	struct dma_fence *next;
136 	uint64_t size;
137 	int r;
138 
139 	mutex_lock(&adev->mman.gtt_window_lock);
140 
141 	while (npages) {
142 		size = min(GTT_MAX_PAGES, npages);
143 
144 		if (direction == FROM_VRAM_TO_RAM) {
145 			gart_s = svm_migrate_direct_mapping_addr(adev, *vram);
146 			r = svm_migrate_gart_map(ring, size, sys, &gart_d, 0);
147 
148 		} else if (direction == FROM_RAM_TO_VRAM) {
149 			r = svm_migrate_gart_map(ring, size, sys, &gart_s,
150 						 KFD_IOCTL_SVM_FLAG_GPU_RO);
151 			gart_d = svm_migrate_direct_mapping_addr(adev, *vram);
152 		}
153 		if (r) {
154 			pr_debug("failed %d to create gart mapping\n", r);
155 			goto out_unlock;
156 		}
157 
158 		r = amdgpu_copy_buffer(ring, gart_s, gart_d, size * PAGE_SIZE,
159 				       NULL, &next, false, true, false);
160 		if (r) {
161 			pr_debug("failed %d to copy memory\n", r);
162 			goto out_unlock;
163 		}
164 
165 		dma_fence_put(*mfence);
166 		*mfence = next;
167 		npages -= size;
168 		if (npages) {
169 			sys += size;
170 			vram += size;
171 		}
172 	}
173 
174 out_unlock:
175 	mutex_unlock(&adev->mman.gtt_window_lock);
176 
177 	return r;
178 }
179 
180 /**
181  * svm_migrate_copy_done - wait for memory copy sdma is done
182  *
183  * @adev: amdgpu device the sdma memory copy is executing on
184  * @mfence: migrate fence
185  *
186  * Wait for dma fence is signaled, if the copy ssplit into multiple sdma
187  * operations, this is the last sdma operation fence.
188  *
189  * Context: called after svm_migrate_copy_memory
190  *
191  * Return:
192  * 0		- success
193  * otherwise	- error code from dma fence signal
194  */
195 static int
196 svm_migrate_copy_done(struct amdgpu_device *adev, struct dma_fence *mfence)
197 {
198 	int r = 0;
199 
200 	if (mfence) {
201 		r = dma_fence_wait(mfence, false);
202 		dma_fence_put(mfence);
203 		pr_debug("sdma copy memory fence done\n");
204 	}
205 
206 	return r;
207 }
208 
209 unsigned long
210 svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long addr)
211 {
212 	return (addr + adev->kfd.dev->pgmap.range.start) >> PAGE_SHIFT;
213 }
214 
215 static void
216 svm_migrate_get_vram_page(struct svm_range *prange, unsigned long pfn)
217 {
218 	struct page *page;
219 
220 	page = pfn_to_page(pfn);
221 	svm_range_bo_ref(prange->svm_bo);
222 	page->zone_device_data = prange->svm_bo;
223 	get_page(page);
224 	lock_page(page);
225 }
226 
227 static void
228 svm_migrate_put_vram_page(struct amdgpu_device *adev, unsigned long addr)
229 {
230 	struct page *page;
231 
232 	page = pfn_to_page(svm_migrate_addr_to_pfn(adev, addr));
233 	unlock_page(page);
234 	put_page(page);
235 }
236 
237 static unsigned long
238 svm_migrate_addr(struct amdgpu_device *adev, struct page *page)
239 {
240 	unsigned long addr;
241 
242 	addr = page_to_pfn(page) << PAGE_SHIFT;
243 	return (addr - adev->kfd.dev->pgmap.range.start);
244 }
245 
246 static struct page *
247 svm_migrate_get_sys_page(struct vm_area_struct *vma, unsigned long addr)
248 {
249 	struct page *page;
250 
251 	page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
252 	if (page)
253 		lock_page(page);
254 
255 	return page;
256 }
257 
258 static void svm_migrate_put_sys_page(unsigned long addr)
259 {
260 	struct page *page;
261 
262 	page = pfn_to_page(addr >> PAGE_SHIFT);
263 	unlock_page(page);
264 	put_page(page);
265 }
266 
267 static int
268 svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
269 			 struct migrate_vma *migrate, struct dma_fence **mfence,
270 			 dma_addr_t *scratch)
271 {
272 	uint64_t npages = migrate->cpages;
273 	struct device *dev = adev->dev;
274 	struct amdgpu_res_cursor cursor;
275 	dma_addr_t *src;
276 	uint64_t *dst;
277 	uint64_t i, j;
278 	int r;
279 
280 	pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start,
281 		 prange->last);
282 
283 	src = scratch;
284 	dst = (uint64_t *)(scratch + npages);
285 
286 	r = svm_range_vram_node_new(adev, prange, true);
287 	if (r) {
288 		pr_debug("failed %d get 0x%llx pages from vram\n", r, npages);
289 		goto out;
290 	}
291 
292 	amdgpu_res_first(prange->ttm_res, prange->offset << PAGE_SHIFT,
293 			 npages << PAGE_SHIFT, &cursor);
294 	for (i = j = 0; i < npages; i++) {
295 		struct page *spage;
296 
297 		spage = migrate_pfn_to_page(migrate->src[i]);
298 		if (spage && !is_zone_device_page(spage)) {
299 			dst[i] = cursor.start + (j << PAGE_SHIFT);
300 			migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
301 			svm_migrate_get_vram_page(prange, migrate->dst[i]);
302 			migrate->dst[i] = migrate_pfn(migrate->dst[i]);
303 			migrate->dst[i] |= MIGRATE_PFN_LOCKED;
304 			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,
305 					      DMA_TO_DEVICE);
306 			r = dma_mapping_error(dev, src[i]);
307 			if (r) {
308 				pr_debug("failed %d dma_map_page\n", r);
309 				goto out_free_vram_pages;
310 			}
311 		} else {
312 			if (j) {
313 				r = svm_migrate_copy_memory_gart(
314 						adev, src + i - j,
315 						dst + i - j, j,
316 						FROM_RAM_TO_VRAM,
317 						mfence);
318 				if (r)
319 					goto out_free_vram_pages;
320 				amdgpu_res_next(&cursor, j << PAGE_SHIFT);
321 				j = 0;
322 			} else {
323 				amdgpu_res_next(&cursor, PAGE_SIZE);
324 			}
325 			continue;
326 		}
327 
328 		pr_debug("dma mapping src to 0x%llx, page_to_pfn 0x%lx\n",
329 			 src[i] >> PAGE_SHIFT, page_to_pfn(spage));
330 
331 		if (j >= (cursor.size >> PAGE_SHIFT) - 1 && i < npages - 1) {
332 			r = svm_migrate_copy_memory_gart(adev, src + i - j,
333 							 dst + i - j, j + 1,
334 							 FROM_RAM_TO_VRAM,
335 							 mfence);
336 			if (r)
337 				goto out_free_vram_pages;
338 			amdgpu_res_next(&cursor, (j + 1) * PAGE_SIZE);
339 			j= 0;
340 		} else {
341 			j++;
342 		}
343 	}
344 
345 	r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j,
346 					 FROM_RAM_TO_VRAM, mfence);
347 
348 out_free_vram_pages:
349 	if (r) {
350 		pr_debug("failed %d to copy memory to vram\n", r);
351 		while (i--) {
352 			svm_migrate_put_vram_page(adev, dst[i]);
353 			migrate->dst[i] = 0;
354 		}
355 	}
356 
357 #ifdef DEBUG_FORCE_MIXED_DOMAINS
358 	for (i = 0, j = 0; i < npages; i += 4, j++) {
359 		if (j & 1)
360 			continue;
361 		svm_migrate_put_vram_page(adev, dst[i]);
362 		migrate->dst[i] = 0;
363 		svm_migrate_put_vram_page(adev, dst[i + 1]);
364 		migrate->dst[i + 1] = 0;
365 		svm_migrate_put_vram_page(adev, dst[i + 2]);
366 		migrate->dst[i + 2] = 0;
367 		svm_migrate_put_vram_page(adev, dst[i + 3]);
368 		migrate->dst[i + 3] = 0;
369 	}
370 #endif
371 out:
372 	return r;
373 }
374 
375 static int
376 svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
377 			struct vm_area_struct *vma, uint64_t start,
378 			uint64_t end)
379 {
380 	uint64_t npages = (end - start) >> PAGE_SHIFT;
381 	struct kfd_process_device *pdd;
382 	struct dma_fence *mfence = NULL;
383 	struct migrate_vma migrate;
384 	dma_addr_t *scratch;
385 	size_t size;
386 	void *buf;
387 	int r = -ENOMEM;
388 
389 	memset(&migrate, 0, sizeof(migrate));
390 	migrate.vma = vma;
391 	migrate.start = start;
392 	migrate.end = end;
393 	migrate.flags = MIGRATE_VMA_SELECT_SYSTEM;
394 	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
395 
396 	size = 2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t);
397 	size *= npages;
398 	buf = kvmalloc(size, GFP_KERNEL | __GFP_ZERO);
399 	if (!buf)
400 		goto out;
401 
402 	migrate.src = buf;
403 	migrate.dst = migrate.src + npages;
404 	scratch = (dma_addr_t *)(migrate.dst + npages);
405 
406 	r = migrate_vma_setup(&migrate);
407 	if (r) {
408 		pr_debug("failed %d prepare migrate svms 0x%p [0x%lx 0x%lx]\n",
409 			 r, prange->svms, prange->start, prange->last);
410 		goto out_free;
411 	}
412 	if (migrate.cpages != npages) {
413 		pr_debug("Partial migration. 0x%lx/0x%llx pages can be migrated\n",
414 			 migrate.cpages,
415 			 npages);
416 	}
417 
418 	if (migrate.cpages) {
419 		r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence,
420 					     scratch);
421 		migrate_vma_pages(&migrate);
422 		svm_migrate_copy_done(adev, mfence);
423 		migrate_vma_finalize(&migrate);
424 	}
425 
426 	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
427 	svm_range_free_dma_mappings(prange);
428 
429 out_free:
430 	kvfree(buf);
431 out:
432 	if (!r) {
433 		pdd = svm_range_get_pdd_by_adev(prange, adev);
434 		if (pdd)
435 			WRITE_ONCE(pdd->page_in, pdd->page_in + migrate.cpages);
436 	}
437 
438 	return r;
439 }
440 
441 /**
442  * svm_migrate_ram_to_vram - migrate svm range from system to device
443  * @prange: range structure
444  * @best_loc: the device to migrate to
445  * @mm: the process mm structure
446  *
447  * Context: Process context, caller hold mmap read lock, svms lock, prange lock
448  *
449  * Return:
450  * 0 - OK, otherwise error code
451  */
452 static int
453 svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
454 			struct mm_struct *mm)
455 {
456 	unsigned long addr, start, end;
457 	struct vm_area_struct *vma;
458 	struct amdgpu_device *adev;
459 	int r = 0;
460 
461 	if (prange->actual_loc == best_loc) {
462 		pr_debug("svms 0x%p [0x%lx 0x%lx] already on best_loc 0x%x\n",
463 			 prange->svms, prange->start, prange->last, best_loc);
464 		return 0;
465 	}
466 
467 	adev = svm_range_get_adev_by_id(prange, best_loc);
468 	if (!adev) {
469 		pr_debug("failed to get device by id 0x%x\n", best_loc);
470 		return -ENODEV;
471 	}
472 
473 	pr_debug("svms 0x%p [0x%lx 0x%lx] to gpu 0x%x\n", prange->svms,
474 		 prange->start, prange->last, best_loc);
475 
476 	/* FIXME: workaround for page locking bug with invalid pages */
477 	svm_range_prefault(prange, mm, SVM_ADEV_PGMAP_OWNER(adev));
478 
479 	start = prange->start << PAGE_SHIFT;
480 	end = (prange->last + 1) << PAGE_SHIFT;
481 
482 	for (addr = start; addr < end;) {
483 		unsigned long next;
484 
485 		vma = find_vma(mm, addr);
486 		if (!vma || addr < vma->vm_start)
487 			break;
488 
489 		next = min(vma->vm_end, end);
490 		r = svm_migrate_vma_to_vram(adev, prange, vma, addr, next);
491 		if (r) {
492 			pr_debug("failed to migrate\n");
493 			break;
494 		}
495 		addr = next;
496 	}
497 
498 	if (!r)
499 		prange->actual_loc = best_loc;
500 
501 	return r;
502 }
503 
504 static void svm_migrate_page_free(struct page *page)
505 {
506 	struct svm_range_bo *svm_bo = page->zone_device_data;
507 
508 	if (svm_bo) {
509 		pr_debug("svm_bo ref left: %d\n", kref_read(&svm_bo->kref));
510 		svm_range_bo_unref(svm_bo);
511 	}
512 }
513 
514 static int
515 svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
516 			struct migrate_vma *migrate, struct dma_fence **mfence,
517 			dma_addr_t *scratch, uint64_t npages)
518 {
519 	struct device *dev = adev->dev;
520 	uint64_t *src;
521 	dma_addr_t *dst;
522 	struct page *dpage;
523 	uint64_t i = 0, j;
524 	uint64_t addr;
525 	int r = 0;
526 
527 	pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start,
528 		 prange->last);
529 
530 	addr = prange->start << PAGE_SHIFT;
531 
532 	src = (uint64_t *)(scratch + npages);
533 	dst = scratch;
534 
535 	for (i = 0, j = 0; i < npages; i++, addr += PAGE_SIZE) {
536 		struct page *spage;
537 
538 		spage = migrate_pfn_to_page(migrate->src[i]);
539 		if (!spage || !is_zone_device_page(spage)) {
540 			pr_debug("invalid page. Could be in CPU already svms 0x%p [0x%lx 0x%lx]\n",
541 				 prange->svms, prange->start, prange->last);
542 			if (j) {
543 				r = svm_migrate_copy_memory_gart(adev, dst + i - j,
544 								 src + i - j, j,
545 								 FROM_VRAM_TO_RAM,
546 								 mfence);
547 				if (r)
548 					goto out_oom;
549 				j = 0;
550 			}
551 			continue;
552 		}
553 		src[i] = svm_migrate_addr(adev, spage);
554 		if (i > 0 && src[i] != src[i - 1] + PAGE_SIZE) {
555 			r = svm_migrate_copy_memory_gart(adev, dst + i - j,
556 							 src + i - j, j,
557 							 FROM_VRAM_TO_RAM,
558 							 mfence);
559 			if (r)
560 				goto out_oom;
561 			j = 0;
562 		}
563 
564 		dpage = svm_migrate_get_sys_page(migrate->vma, addr);
565 		if (!dpage) {
566 			pr_debug("failed get page svms 0x%p [0x%lx 0x%lx]\n",
567 				 prange->svms, prange->start, prange->last);
568 			r = -ENOMEM;
569 			goto out_oom;
570 		}
571 
572 		dst[i] = dma_map_page(dev, dpage, 0, PAGE_SIZE, DMA_FROM_DEVICE);
573 		r = dma_mapping_error(dev, dst[i]);
574 		if (r) {
575 			pr_debug("failed %d dma_map_page\n", r);
576 			goto out_oom;
577 		}
578 
579 		pr_debug("dma mapping dst to 0x%llx, page_to_pfn 0x%lx\n",
580 			      dst[i] >> PAGE_SHIFT, page_to_pfn(dpage));
581 
582 		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));
583 		migrate->dst[i] |= MIGRATE_PFN_LOCKED;
584 		j++;
585 	}
586 
587 	r = svm_migrate_copy_memory_gart(adev, dst + i - j, src + i - j, j,
588 					 FROM_VRAM_TO_RAM, mfence);
589 
590 out_oom:
591 	if (r) {
592 		pr_debug("failed %d copy to ram\n", r);
593 		while (i--) {
594 			svm_migrate_put_sys_page(dst[i]);
595 			migrate->dst[i] = 0;
596 		}
597 	}
598 
599 	return r;
600 }
601 
602 static int
603 svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
604 		       struct vm_area_struct *vma, uint64_t start, uint64_t end)
605 {
606 	uint64_t npages = (end - start) >> PAGE_SHIFT;
607 	struct kfd_process_device *pdd;
608 	struct dma_fence *mfence = NULL;
609 	struct migrate_vma migrate;
610 	dma_addr_t *scratch;
611 	size_t size;
612 	void *buf;
613 	int r = -ENOMEM;
614 
615 	memset(&migrate, 0, sizeof(migrate));
616 	migrate.vma = vma;
617 	migrate.start = start;
618 	migrate.end = end;
619 	migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
620 	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
621 
622 	size = 2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t);
623 	size *= npages;
624 	buf = kvmalloc(size, GFP_KERNEL | __GFP_ZERO);
625 	if (!buf)
626 		goto out;
627 
628 	migrate.src = buf;
629 	migrate.dst = migrate.src + npages;
630 	scratch = (dma_addr_t *)(migrate.dst + npages);
631 
632 	r = migrate_vma_setup(&migrate);
633 	if (r) {
634 		pr_debug("failed %d prepare migrate svms 0x%p [0x%lx 0x%lx]\n",
635 			 r, prange->svms, prange->start, prange->last);
636 		goto out_free;
637 	}
638 
639 	pr_debug("cpages %ld\n", migrate.cpages);
640 
641 	if (migrate.cpages) {
642 		r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
643 					    scratch, npages);
644 		migrate_vma_pages(&migrate);
645 		svm_migrate_copy_done(adev, mfence);
646 		migrate_vma_finalize(&migrate);
647 	} else {
648 		pr_debug("failed collect migrate device pages [0x%lx 0x%lx]\n",
649 			 prange->start, prange->last);
650 	}
651 
652 	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
653 
654 out_free:
655 	kvfree(buf);
656 out:
657 	if (!r) {
658 		pdd = svm_range_get_pdd_by_adev(prange, adev);
659 		if (pdd)
660 			WRITE_ONCE(pdd->page_out,
661 				   pdd->page_out + migrate.cpages);
662 	}
663 	return r;
664 }
665 
666 /**
667  * svm_migrate_vram_to_ram - migrate svm range from device to system
668  * @prange: range structure
669  * @mm: process mm, use current->mm if NULL
670  *
671  * Context: Process context, caller hold mmap read lock, svms lock, prange lock
672  *
673  * Return:
674  * 0 - OK, otherwise error code
675  */
676 int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
677 {
678 	struct amdgpu_device *adev;
679 	struct vm_area_struct *vma;
680 	unsigned long addr;
681 	unsigned long start;
682 	unsigned long end;
683 	int r = 0;
684 
685 	if (!prange->actual_loc) {
686 		pr_debug("[0x%lx 0x%lx] already migrated to ram\n",
687 			 prange->start, prange->last);
688 		return 0;
689 	}
690 
691 	adev = svm_range_get_adev_by_id(prange, prange->actual_loc);
692 	if (!adev) {
693 		pr_debug("failed to get device by id 0x%x\n",
694 			 prange->actual_loc);
695 		return -ENODEV;
696 	}
697 
698 	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] from gpu 0x%x to ram\n",
699 		 prange->svms, prange, prange->start, prange->last,
700 		 prange->actual_loc);
701 
702 	start = prange->start << PAGE_SHIFT;
703 	end = (prange->last + 1) << PAGE_SHIFT;
704 
705 	for (addr = start; addr < end;) {
706 		unsigned long next;
707 
708 		vma = find_vma(mm, addr);
709 		if (!vma || addr < vma->vm_start)
710 			break;
711 
712 		next = min(vma->vm_end, end);
713 		r = svm_migrate_vma_to_ram(adev, prange, vma, addr, next);
714 		if (r) {
715 			pr_debug("failed %d to migrate\n", r);
716 			break;
717 		}
718 		addr = next;
719 	}
720 
721 	if (!r) {
722 		svm_range_vram_node_free(prange);
723 		prange->actual_loc = 0;
724 	}
725 	return r;
726 }
727 
728 /**
729  * svm_migrate_vram_to_vram - migrate svm range from device to device
730  * @prange: range structure
731  * @best_loc: the device to migrate to
732  * @mm: process mm, use current->mm if NULL
733  *
734  * Context: Process context, caller hold mmap read lock, svms lock, prange lock
735  *
736  * Return:
737  * 0 - OK, otherwise error code
738  */
739 static int
740 svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
741 			 struct mm_struct *mm)
742 {
743 	int r;
744 
745 	/*
746 	 * TODO: for both devices with PCIe large bar or on same xgmi hive, skip
747 	 * system memory as migration bridge
748 	 */
749 
750 	pr_debug("from gpu 0x%x to gpu 0x%x\n", prange->actual_loc, best_loc);
751 
752 	r = svm_migrate_vram_to_ram(prange, mm);
753 	if (r)
754 		return r;
755 
756 	return svm_migrate_ram_to_vram(prange, best_loc, mm);
757 }
758 
759 int
760 svm_migrate_to_vram(struct svm_range *prange, uint32_t best_loc,
761 		    struct mm_struct *mm)
762 {
763 	if  (!prange->actual_loc)
764 		return svm_migrate_ram_to_vram(prange, best_loc, mm);
765 	else
766 		return svm_migrate_vram_to_vram(prange, best_loc, mm);
767 
768 }
769 
770 /**
771  * svm_migrate_to_ram - CPU page fault handler
772  * @vmf: CPU vm fault vma, address
773  *
774  * Context: vm fault handler, caller holds the mmap read lock
775  *
776  * Return:
777  * 0 - OK
778  * VM_FAULT_SIGBUS - notice application to have SIGBUS page fault
779  */
780 static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)
781 {
782 	unsigned long addr = vmf->address;
783 	struct vm_area_struct *vma;
784 	enum svm_work_list_ops op;
785 	struct svm_range *parent;
786 	struct svm_range *prange;
787 	struct kfd_process *p;
788 	struct mm_struct *mm;
789 	int r = 0;
790 
791 	vma = vmf->vma;
792 	mm = vma->vm_mm;
793 
794 	p = kfd_lookup_process_by_mm(vma->vm_mm);
795 	if (!p) {
796 		pr_debug("failed find process at fault address 0x%lx\n", addr);
797 		return VM_FAULT_SIGBUS;
798 	}
799 	addr >>= PAGE_SHIFT;
800 	pr_debug("CPU page fault svms 0x%p address 0x%lx\n", &p->svms, addr);
801 
802 	mutex_lock(&p->svms.lock);
803 
804 	prange = svm_range_from_addr(&p->svms, addr, &parent);
805 	if (!prange) {
806 		pr_debug("cannot find svm range at 0x%lx\n", addr);
807 		r = -EFAULT;
808 		goto out;
809 	}
810 
811 	mutex_lock(&parent->migrate_mutex);
812 	if (prange != parent)
813 		mutex_lock_nested(&prange->migrate_mutex, 1);
814 
815 	if (!prange->actual_loc)
816 		goto out_unlock_prange;
817 
818 	svm_range_lock(parent);
819 	if (prange != parent)
820 		mutex_lock_nested(&prange->lock, 1);
821 	r = svm_range_split_by_granularity(p, mm, addr, parent, prange);
822 	if (prange != parent)
823 		mutex_unlock(&prange->lock);
824 	svm_range_unlock(parent);
825 	if (r) {
826 		pr_debug("failed %d to split range by granularity\n", r);
827 		goto out_unlock_prange;
828 	}
829 
830 	r = svm_migrate_vram_to_ram(prange, mm);
831 	if (r)
832 		pr_debug("failed %d migrate 0x%p [0x%lx 0x%lx] to ram\n", r,
833 			 prange, prange->start, prange->last);
834 
835 	/* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
836 	if (p->xnack_enabled && parent == prange)
837 		op = SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP;
838 	else
839 		op = SVM_OP_UPDATE_RANGE_NOTIFIER;
840 	svm_range_add_list_work(&p->svms, parent, mm, op);
841 	schedule_deferred_list_work(&p->svms);
842 
843 out_unlock_prange:
844 	if (prange != parent)
845 		mutex_unlock(&prange->migrate_mutex);
846 	mutex_unlock(&parent->migrate_mutex);
847 out:
848 	mutex_unlock(&p->svms.lock);
849 	kfd_unref_process(p);
850 
851 	pr_debug("CPU fault svms 0x%p address 0x%lx done\n", &p->svms, addr);
852 
853 	return r ? VM_FAULT_SIGBUS : 0;
854 }
855 
856 static const struct dev_pagemap_ops svm_migrate_pgmap_ops = {
857 	.page_free		= svm_migrate_page_free,
858 	.migrate_to_ram		= svm_migrate_to_ram,
859 };
860 
861 /* Each VRAM page uses sizeof(struct page) on system memory */
862 #define SVM_HMM_PAGE_STRUCT_SIZE(size) ((size)/PAGE_SIZE * sizeof(struct page))
863 
864 int svm_migrate_init(struct amdgpu_device *adev)
865 {
866 	struct kfd_dev *kfddev = adev->kfd.dev;
867 	struct dev_pagemap *pgmap;
868 	struct resource *res;
869 	unsigned long size;
870 	void *r;
871 
872 	/* Page migration works on Vega10 or newer */
873 	if (kfddev->device_info->asic_family < CHIP_VEGA10)
874 		return -EINVAL;
875 
876 	pgmap = &kfddev->pgmap;
877 	memset(pgmap, 0, sizeof(*pgmap));
878 
879 	/* TODO: register all vram to HMM for now.
880 	 * should remove reserved size
881 	 */
882 	size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
883 	res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
884 	if (IS_ERR(res))
885 		return -ENOMEM;
886 
887 	pgmap->type = MEMORY_DEVICE_PRIVATE;
888 	pgmap->nr_range = 1;
889 	pgmap->range.start = res->start;
890 	pgmap->range.end = res->end;
891 	pgmap->ops = &svm_migrate_pgmap_ops;
892 	pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
893 	pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
894 
895 	/* Device manager releases device-specific resources, memory region and
896 	 * pgmap when driver disconnects from device.
897 	 */
898 	r = devm_memremap_pages(adev->dev, pgmap);
899 	if (IS_ERR(r)) {
900 		pr_err("failed to register HMM device memory\n");
901 
902 		/* Disable SVM support capability */
903 		pgmap->type = 0;
904 		devm_release_mem_region(adev->dev, res->start,
905 					res->end - res->start + 1);
906 		return PTR_ERR(r);
907 	}
908 
909 	pr_debug("reserve %ldMB system memory for VRAM pages struct\n",
910 		 SVM_HMM_PAGE_STRUCT_SIZE(size) >> 20);
911 
912 	amdgpu_amdkfd_reserve_system_mem(SVM_HMM_PAGE_STRUCT_SIZE(size));
913 
914 	pr_info("HMM registered %ldMB device memory\n", size >> 20);
915 
916 	return 0;
917 }
918