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 #include <linux/types.h>
24 #include <linux/hmm.h>
25 #include <linux/dma-direction.h>
26 #include <linux/dma-mapping.h>
27 #include "amdgpu_sync.h"
28 #include "amdgpu_object.h"
29 #include "amdgpu_vm.h"
30 #include "amdgpu_mn.h"
31 #include "amdgpu_res_cursor.h"
32 #include "kfd_priv.h"
33 #include "kfd_svm.h"
34 #include "kfd_migrate.h"
35 
36 #ifdef dev_fmt
37 #undef dev_fmt
38 #endif
39 #define dev_fmt(fmt) "kfd_migrate: %s: " fmt, __func__
40 
41 static uint64_t
42 svm_migrate_direct_mapping_addr(struct amdgpu_device *adev, uint64_t addr)
43 {
44 	return addr + amdgpu_ttm_domain_start(adev, TTM_PL_VRAM);
45 }
46 
47 static int
48 svm_migrate_gart_map(struct amdgpu_ring *ring, uint64_t npages,
49 		     dma_addr_t *addr, uint64_t *gart_addr, uint64_t flags)
50 {
51 	struct amdgpu_device *adev = ring->adev;
52 	struct amdgpu_job *job;
53 	unsigned int num_dw, num_bytes;
54 	struct dma_fence *fence;
55 	uint64_t src_addr, dst_addr;
56 	uint64_t pte_flags;
57 	void *cpu_addr;
58 	int r;
59 
60 	/* use gart window 0 */
61 	*gart_addr = adev->gmc.gart_start;
62 
63 	num_dw = ALIGN(adev->mman.buffer_funcs->copy_num_dw, 8);
64 	num_bytes = npages * 8;
65 
66 	r = amdgpu_job_alloc_with_ib(adev, num_dw * 4 + num_bytes,
67 				     AMDGPU_IB_POOL_DELAYED, &job);
68 	if (r)
69 		return r;
70 
71 	src_addr = num_dw * 4;
72 	src_addr += job->ibs[0].gpu_addr;
73 
74 	dst_addr = amdgpu_bo_gpu_offset(adev->gart.bo);
75 	amdgpu_emit_copy_buffer(adev, &job->ibs[0], src_addr,
76 				dst_addr, num_bytes, false);
77 
78 	amdgpu_ring_pad_ib(ring, &job->ibs[0]);
79 	WARN_ON(job->ibs[0].length_dw > num_dw);
80 
81 	pte_flags = AMDGPU_PTE_VALID | AMDGPU_PTE_READABLE;
82 	pte_flags |= AMDGPU_PTE_SYSTEM | AMDGPU_PTE_SNOOPED;
83 	if (!(flags & KFD_IOCTL_SVM_FLAG_GPU_RO))
84 		pte_flags |= AMDGPU_PTE_WRITEABLE;
85 	pte_flags |= adev->gart.gart_pte_flags;
86 
87 	cpu_addr = &job->ibs[0].ptr[num_dw];
88 
89 	r = amdgpu_gart_map(adev, 0, npages, addr, pte_flags, cpu_addr);
90 	if (r)
91 		goto error_free;
92 
93 	r = amdgpu_job_submit(job, &adev->mman.entity,
94 			      AMDGPU_FENCE_OWNER_UNDEFINED, &fence);
95 	if (r)
96 		goto error_free;
97 
98 	dma_fence_put(fence);
99 
100 	return r;
101 
102 error_free:
103 	amdgpu_job_free(job);
104 	return r;
105 }
106 
107 /**
108  * svm_migrate_copy_memory_gart - sdma copy data between ram and vram
109  *
110  * @adev: amdgpu device the sdma ring running
111  * @src: source page address array
112  * @dst: destination page address array
113  * @npages: number of pages to copy
114  * @direction: enum MIGRATION_COPY_DIR
115  * @mfence: output, sdma fence to signal after sdma is done
116  *
117  * ram address uses GART table continuous entries mapping to ram pages,
118  * vram address uses direct mapping of vram pages, which must have npages
119  * number of continuous pages.
120  * GART update and sdma uses same buf copy function ring, sdma is splited to
121  * multiple GTT_MAX_PAGES transfer, all sdma operations are serialized, wait for
122  * the last sdma finish fence which is returned to check copy memory is done.
123  *
124  * Context: Process context, takes and releases gtt_window_lock
125  *
126  * Return:
127  * 0 - OK, otherwise error code
128  */
129 
130 static int
131 svm_migrate_copy_memory_gart(struct amdgpu_device *adev, dma_addr_t *sys,
132 			     uint64_t *vram, uint64_t npages,
133 			     enum MIGRATION_COPY_DIR direction,
134 			     struct dma_fence **mfence)
135 {
136 	const uint64_t GTT_MAX_PAGES = AMDGPU_GTT_MAX_TRANSFER_SIZE;
137 	struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
138 	uint64_t gart_s, gart_d;
139 	struct dma_fence *next;
140 	uint64_t size;
141 	int r;
142 
143 	mutex_lock(&adev->mman.gtt_window_lock);
144 
145 	while (npages) {
146 		size = min(GTT_MAX_PAGES, npages);
147 
148 		if (direction == FROM_VRAM_TO_RAM) {
149 			gart_s = svm_migrate_direct_mapping_addr(adev, *vram);
150 			r = svm_migrate_gart_map(ring, size, sys, &gart_d, 0);
151 
152 		} else if (direction == FROM_RAM_TO_VRAM) {
153 			r = svm_migrate_gart_map(ring, size, sys, &gart_s,
154 						 KFD_IOCTL_SVM_FLAG_GPU_RO);
155 			gart_d = svm_migrate_direct_mapping_addr(adev, *vram);
156 		}
157 		if (r) {
158 			dev_err(adev->dev, "fail %d create gart mapping\n", r);
159 			goto out_unlock;
160 		}
161 
162 		r = amdgpu_copy_buffer(ring, gart_s, gart_d, size * PAGE_SIZE,
163 				       NULL, &next, false, true, false);
164 		if (r) {
165 			dev_err(adev->dev, "fail %d to copy memory\n", r);
166 			goto out_unlock;
167 		}
168 
169 		dma_fence_put(*mfence);
170 		*mfence = next;
171 		npages -= size;
172 		if (npages) {
173 			sys += size;
174 			vram += size;
175 		}
176 	}
177 
178 out_unlock:
179 	mutex_unlock(&adev->mman.gtt_window_lock);
180 
181 	return r;
182 }
183 
184 /**
185  * svm_migrate_copy_done - wait for memory copy sdma is done
186  *
187  * @adev: amdgpu device the sdma memory copy is executing on
188  * @mfence: migrate fence
189  *
190  * Wait for dma fence is signaled, if the copy ssplit into multiple sdma
191  * operations, this is the last sdma operation fence.
192  *
193  * Context: called after svm_migrate_copy_memory
194  *
195  * Return:
196  * 0		- success
197  * otherwise	- error code from dma fence signal
198  */
199 static int
200 svm_migrate_copy_done(struct amdgpu_device *adev, struct dma_fence *mfence)
201 {
202 	int r = 0;
203 
204 	if (mfence) {
205 		r = dma_fence_wait(mfence, false);
206 		dma_fence_put(mfence);
207 		pr_debug("sdma copy memory fence done\n");
208 	}
209 
210 	return r;
211 }
212 
213 unsigned long
214 svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long addr)
215 {
216 	return (addr + adev->kfd.dev->pgmap.range.start) >> PAGE_SHIFT;
217 }
218 
219 static void
220 svm_migrate_get_vram_page(struct svm_range *prange, unsigned long pfn)
221 {
222 	struct page *page;
223 
224 	page = pfn_to_page(pfn);
225 	svm_range_bo_ref(prange->svm_bo);
226 	page->zone_device_data = prange->svm_bo;
227 	get_page(page);
228 	lock_page(page);
229 }
230 
231 static void
232 svm_migrate_put_vram_page(struct amdgpu_device *adev, unsigned long addr)
233 {
234 	struct page *page;
235 
236 	page = pfn_to_page(svm_migrate_addr_to_pfn(adev, addr));
237 	unlock_page(page);
238 	put_page(page);
239 }
240 
241 static unsigned long
242 svm_migrate_addr(struct amdgpu_device *adev, struct page *page)
243 {
244 	unsigned long addr;
245 
246 	addr = page_to_pfn(page) << PAGE_SHIFT;
247 	return (addr - adev->kfd.dev->pgmap.range.start);
248 }
249 
250 static struct page *
251 svm_migrate_get_sys_page(struct vm_area_struct *vma, unsigned long addr)
252 {
253 	struct page *page;
254 
255 	page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
256 	if (page)
257 		lock_page(page);
258 
259 	return page;
260 }
261 
262 static void svm_migrate_put_sys_page(unsigned long addr)
263 {
264 	struct page *page;
265 
266 	page = pfn_to_page(addr >> PAGE_SHIFT);
267 	unlock_page(page);
268 	put_page(page);
269 }
270 
271 static unsigned long svm_migrate_successful_pages(struct migrate_vma *migrate)
272 {
273 	unsigned long cpages = 0;
274 	unsigned long i;
275 
276 	for (i = 0; i < migrate->npages; i++) {
277 		if (migrate->src[i] & MIGRATE_PFN_VALID &&
278 		    migrate->src[i] & MIGRATE_PFN_MIGRATE)
279 			cpages++;
280 	}
281 	return cpages;
282 }
283 
284 static unsigned long svm_migrate_unsuccessful_pages(struct migrate_vma *migrate)
285 {
286 	unsigned long upages = 0;
287 	unsigned long i;
288 
289 	for (i = 0; i < migrate->npages; i++) {
290 		if (migrate->src[i] & MIGRATE_PFN_VALID &&
291 		    !(migrate->src[i] & MIGRATE_PFN_MIGRATE))
292 			upages++;
293 	}
294 	return upages;
295 }
296 
297 static int
298 svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
299 			 struct migrate_vma *migrate, struct dma_fence **mfence,
300 			 dma_addr_t *scratch)
301 {
302 	uint64_t npages = migrate->cpages;
303 	struct device *dev = adev->dev;
304 	struct amdgpu_res_cursor cursor;
305 	dma_addr_t *src;
306 	uint64_t *dst;
307 	uint64_t i, j;
308 	int r;
309 
310 	pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start,
311 		 prange->last);
312 
313 	src = scratch;
314 	dst = (uint64_t *)(scratch + npages);
315 
316 	r = svm_range_vram_node_new(adev, prange, true);
317 	if (r) {
318 		dev_err(adev->dev, "fail %d to alloc vram\n", r);
319 		goto out;
320 	}
321 
322 	amdgpu_res_first(prange->ttm_res, prange->offset << PAGE_SHIFT,
323 			 npages << PAGE_SHIFT, &cursor);
324 	for (i = j = 0; i < npages; i++) {
325 		struct page *spage;
326 
327 		spage = migrate_pfn_to_page(migrate->src[i]);
328 		if (spage && !is_zone_device_page(spage)) {
329 			dst[i] = cursor.start + (j << PAGE_SHIFT);
330 			migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
331 			svm_migrate_get_vram_page(prange, migrate->dst[i]);
332 			migrate->dst[i] = migrate_pfn(migrate->dst[i]);
333 			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,
334 					      DMA_TO_DEVICE);
335 			r = dma_mapping_error(dev, src[i]);
336 			if (r) {
337 				dev_err(adev->dev, "fail %d dma_map_page\n", r);
338 				goto out_free_vram_pages;
339 			}
340 		} else {
341 			if (j) {
342 				r = svm_migrate_copy_memory_gart(
343 						adev, src + i - j,
344 						dst + i - j, j,
345 						FROM_RAM_TO_VRAM,
346 						mfence);
347 				if (r)
348 					goto out_free_vram_pages;
349 				amdgpu_res_next(&cursor, j << PAGE_SHIFT);
350 				j = 0;
351 			} else {
352 				amdgpu_res_next(&cursor, PAGE_SIZE);
353 			}
354 			continue;
355 		}
356 
357 		pr_debug_ratelimited("dma mapping src to 0x%llx, pfn 0x%lx\n",
358 				     src[i] >> PAGE_SHIFT, page_to_pfn(spage));
359 
360 		if (j >= (cursor.size >> PAGE_SHIFT) - 1 && i < npages - 1) {
361 			r = svm_migrate_copy_memory_gart(adev, src + i - j,
362 							 dst + i - j, j + 1,
363 							 FROM_RAM_TO_VRAM,
364 							 mfence);
365 			if (r)
366 				goto out_free_vram_pages;
367 			amdgpu_res_next(&cursor, (j + 1) * PAGE_SIZE);
368 			j= 0;
369 		} else {
370 			j++;
371 		}
372 	}
373 
374 	r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j,
375 					 FROM_RAM_TO_VRAM, mfence);
376 
377 out_free_vram_pages:
378 	if (r) {
379 		pr_debug("failed %d to copy memory to vram\n", r);
380 		while (i--) {
381 			svm_migrate_put_vram_page(adev, dst[i]);
382 			migrate->dst[i] = 0;
383 		}
384 	}
385 
386 #ifdef DEBUG_FORCE_MIXED_DOMAINS
387 	for (i = 0, j = 0; i < npages; i += 4, j++) {
388 		if (j & 1)
389 			continue;
390 		svm_migrate_put_vram_page(adev, dst[i]);
391 		migrate->dst[i] = 0;
392 		svm_migrate_put_vram_page(adev, dst[i + 1]);
393 		migrate->dst[i + 1] = 0;
394 		svm_migrate_put_vram_page(adev, dst[i + 2]);
395 		migrate->dst[i + 2] = 0;
396 		svm_migrate_put_vram_page(adev, dst[i + 3]);
397 		migrate->dst[i + 3] = 0;
398 	}
399 #endif
400 out:
401 	return r;
402 }
403 
404 static long
405 svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
406 			struct vm_area_struct *vma, uint64_t start,
407 			uint64_t end)
408 {
409 	uint64_t npages = (end - start) >> PAGE_SHIFT;
410 	struct kfd_process_device *pdd;
411 	struct dma_fence *mfence = NULL;
412 	struct migrate_vma migrate;
413 	unsigned long cpages = 0;
414 	dma_addr_t *scratch;
415 	size_t size;
416 	void *buf;
417 	int r = -ENOMEM;
418 
419 	memset(&migrate, 0, sizeof(migrate));
420 	migrate.vma = vma;
421 	migrate.start = start;
422 	migrate.end = end;
423 	migrate.flags = MIGRATE_VMA_SELECT_SYSTEM;
424 	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
425 
426 	size = 2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t);
427 	size *= npages;
428 	buf = kvmalloc(size, GFP_KERNEL | __GFP_ZERO);
429 	if (!buf)
430 		goto out;
431 
432 	migrate.src = buf;
433 	migrate.dst = migrate.src + npages;
434 	scratch = (dma_addr_t *)(migrate.dst + npages);
435 
436 	r = migrate_vma_setup(&migrate);
437 	if (r) {
438 		dev_err(adev->dev, "vma setup fail %d range [0x%lx 0x%lx]\n", r,
439 			prange->start, prange->last);
440 		goto out_free;
441 	}
442 
443 	cpages = migrate.cpages;
444 	if (!cpages) {
445 		pr_debug("failed collect migrate sys pages [0x%lx 0x%lx]\n",
446 			 prange->start, prange->last);
447 		goto out_free;
448 	}
449 	if (cpages != npages)
450 		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
451 			 cpages, npages);
452 	else
453 		pr_debug("0x%lx pages migrated\n", cpages);
454 
455 	r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence, scratch);
456 	migrate_vma_pages(&migrate);
457 
458 	pr_debug("successful/cpages/npages 0x%lx/0x%lx/0x%lx\n",
459 		svm_migrate_successful_pages(&migrate), cpages, migrate.npages);
460 
461 	svm_migrate_copy_done(adev, mfence);
462 	migrate_vma_finalize(&migrate);
463 
464 	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
465 	svm_range_free_dma_mappings(prange);
466 
467 out_free:
468 	kvfree(buf);
469 out:
470 	if (!r && cpages) {
471 		pdd = svm_range_get_pdd_by_adev(prange, adev);
472 		if (pdd)
473 			WRITE_ONCE(pdd->page_in, pdd->page_in + cpages);
474 
475 		return cpages;
476 	}
477 	return r;
478 }
479 
480 /**
481  * svm_migrate_ram_to_vram - migrate svm range from system to device
482  * @prange: range structure
483  * @best_loc: the device to migrate to
484  * @mm: the process mm structure
485  *
486  * Context: Process context, caller hold mmap read lock, svms lock, prange lock
487  *
488  * Return:
489  * 0 - OK, otherwise error code
490  */
491 static int
492 svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
493 			struct mm_struct *mm)
494 {
495 	unsigned long addr, start, end;
496 	struct vm_area_struct *vma;
497 	struct amdgpu_device *adev;
498 	unsigned long cpages = 0;
499 	long r = 0;
500 
501 	if (prange->actual_loc == best_loc) {
502 		pr_debug("svms 0x%p [0x%lx 0x%lx] already on best_loc 0x%x\n",
503 			 prange->svms, prange->start, prange->last, best_loc);
504 		return 0;
505 	}
506 
507 	adev = svm_range_get_adev_by_id(prange, best_loc);
508 	if (!adev) {
509 		pr_debug("failed to get device by id 0x%x\n", best_loc);
510 		return -ENODEV;
511 	}
512 
513 	pr_debug("svms 0x%p [0x%lx 0x%lx] to gpu 0x%x\n", prange->svms,
514 		 prange->start, prange->last, best_loc);
515 
516 	/* FIXME: workaround for page locking bug with invalid pages */
517 	svm_range_prefault(prange, mm, SVM_ADEV_PGMAP_OWNER(adev));
518 
519 	start = prange->start << PAGE_SHIFT;
520 	end = (prange->last + 1) << PAGE_SHIFT;
521 
522 	for (addr = start; addr < end;) {
523 		unsigned long next;
524 
525 		vma = find_vma(mm, addr);
526 		if (!vma || addr < vma->vm_start)
527 			break;
528 
529 		next = min(vma->vm_end, end);
530 		r = svm_migrate_vma_to_vram(adev, prange, vma, addr, next);
531 		if (r < 0) {
532 			pr_debug("failed %ld to migrate\n", r);
533 			break;
534 		} else {
535 			cpages += r;
536 		}
537 		addr = next;
538 	}
539 
540 	if (cpages)
541 		prange->actual_loc = best_loc;
542 
543 	return r < 0 ? r : 0;
544 }
545 
546 static void svm_migrate_page_free(struct page *page)
547 {
548 	struct svm_range_bo *svm_bo = page->zone_device_data;
549 
550 	if (svm_bo) {
551 		pr_debug_ratelimited("ref: %d\n", kref_read(&svm_bo->kref));
552 		svm_range_bo_unref(svm_bo);
553 	}
554 }
555 
556 static int
557 svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
558 			struct migrate_vma *migrate, struct dma_fence **mfence,
559 			dma_addr_t *scratch, uint64_t npages)
560 {
561 	struct device *dev = adev->dev;
562 	uint64_t *src;
563 	dma_addr_t *dst;
564 	struct page *dpage;
565 	uint64_t i = 0, j;
566 	uint64_t addr;
567 	int r = 0;
568 
569 	pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start,
570 		 prange->last);
571 
572 	addr = prange->start << PAGE_SHIFT;
573 
574 	src = (uint64_t *)(scratch + npages);
575 	dst = scratch;
576 
577 	for (i = 0, j = 0; i < npages; i++, addr += PAGE_SIZE) {
578 		struct page *spage;
579 
580 		spage = migrate_pfn_to_page(migrate->src[i]);
581 		if (!spage || !is_zone_device_page(spage)) {
582 			pr_debug("invalid page. Could be in CPU already svms 0x%p [0x%lx 0x%lx]\n",
583 				 prange->svms, prange->start, prange->last);
584 			if (j) {
585 				r = svm_migrate_copy_memory_gart(adev, dst + i - j,
586 								 src + i - j, j,
587 								 FROM_VRAM_TO_RAM,
588 								 mfence);
589 				if (r)
590 					goto out_oom;
591 				j = 0;
592 			}
593 			continue;
594 		}
595 		src[i] = svm_migrate_addr(adev, spage);
596 		if (i > 0 && src[i] != src[i - 1] + PAGE_SIZE) {
597 			r = svm_migrate_copy_memory_gart(adev, dst + i - j,
598 							 src + i - j, j,
599 							 FROM_VRAM_TO_RAM,
600 							 mfence);
601 			if (r)
602 				goto out_oom;
603 			j = 0;
604 		}
605 
606 		dpage = svm_migrate_get_sys_page(migrate->vma, addr);
607 		if (!dpage) {
608 			pr_debug("failed get page svms 0x%p [0x%lx 0x%lx]\n",
609 				 prange->svms, prange->start, prange->last);
610 			r = -ENOMEM;
611 			goto out_oom;
612 		}
613 
614 		dst[i] = dma_map_page(dev, dpage, 0, PAGE_SIZE, DMA_FROM_DEVICE);
615 		r = dma_mapping_error(dev, dst[i]);
616 		if (r) {
617 			dev_err(adev->dev, "fail %d dma_map_page\n", r);
618 			goto out_oom;
619 		}
620 
621 		pr_debug_ratelimited("dma mapping dst to 0x%llx, pfn 0x%lx\n",
622 				     dst[i] >> PAGE_SHIFT, page_to_pfn(dpage));
623 
624 		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));
625 		j++;
626 	}
627 
628 	r = svm_migrate_copy_memory_gart(adev, dst + i - j, src + i - j, j,
629 					 FROM_VRAM_TO_RAM, mfence);
630 
631 out_oom:
632 	if (r) {
633 		pr_debug("failed %d copy to ram\n", r);
634 		while (i--) {
635 			svm_migrate_put_sys_page(dst[i]);
636 			migrate->dst[i] = 0;
637 		}
638 	}
639 
640 	return r;
641 }
642 
643 static long
644 svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
645 		       struct vm_area_struct *vma, uint64_t start, uint64_t end)
646 {
647 	uint64_t npages = (end - start) >> PAGE_SHIFT;
648 	unsigned long upages = npages;
649 	unsigned long cpages = 0;
650 	struct kfd_process_device *pdd;
651 	struct dma_fence *mfence = NULL;
652 	struct migrate_vma migrate;
653 	dma_addr_t *scratch;
654 	size_t size;
655 	void *buf;
656 	int r = -ENOMEM;
657 
658 	memset(&migrate, 0, sizeof(migrate));
659 	migrate.vma = vma;
660 	migrate.start = start;
661 	migrate.end = end;
662 	migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
663 	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
664 
665 	size = 2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t);
666 	size *= npages;
667 	buf = kvmalloc(size, GFP_KERNEL | __GFP_ZERO);
668 	if (!buf)
669 		goto out;
670 
671 	migrate.src = buf;
672 	migrate.dst = migrate.src + npages;
673 	scratch = (dma_addr_t *)(migrate.dst + npages);
674 
675 	r = migrate_vma_setup(&migrate);
676 	if (r) {
677 		dev_err(adev->dev, "vma setup fail %d range [0x%lx 0x%lx]\n", r,
678 			prange->start, prange->last);
679 		goto out_free;
680 	}
681 
682 	cpages = migrate.cpages;
683 	if (!cpages) {
684 		pr_debug("failed collect migrate device pages [0x%lx 0x%lx]\n",
685 			 prange->start, prange->last);
686 		upages = svm_migrate_unsuccessful_pages(&migrate);
687 		goto out_free;
688 	}
689 	if (cpages != npages)
690 		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
691 			 cpages, npages);
692 	else
693 		pr_debug("0x%lx pages migrated\n", cpages);
694 
695 	r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
696 				    scratch, npages);
697 	migrate_vma_pages(&migrate);
698 
699 	upages = svm_migrate_unsuccessful_pages(&migrate);
700 	pr_debug("unsuccessful/cpages/npages 0x%lx/0x%lx/0x%lx\n",
701 		 upages, cpages, migrate.npages);
702 
703 	svm_migrate_copy_done(adev, mfence);
704 	migrate_vma_finalize(&migrate);
705 	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
706 
707 out_free:
708 	kvfree(buf);
709 out:
710 	if (!r && cpages) {
711 		pdd = svm_range_get_pdd_by_adev(prange, adev);
712 		if (pdd)
713 			WRITE_ONCE(pdd->page_out, pdd->page_out + cpages);
714 
715 		return upages;
716 	}
717 	return r ? r : upages;
718 }
719 
720 /**
721  * svm_migrate_vram_to_ram - migrate svm range from device to system
722  * @prange: range structure
723  * @mm: process mm, use current->mm if NULL
724  *
725  * Context: Process context, caller hold mmap read lock, svms lock, prange lock
726  *
727  * Return:
728  * 0 - OK, otherwise error code
729  */
730 int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
731 {
732 	struct amdgpu_device *adev;
733 	struct vm_area_struct *vma;
734 	unsigned long addr;
735 	unsigned long start;
736 	unsigned long end;
737 	unsigned long upages = 0;
738 	long r = 0;
739 
740 	if (!prange->actual_loc) {
741 		pr_debug("[0x%lx 0x%lx] already migrated to ram\n",
742 			 prange->start, prange->last);
743 		return 0;
744 	}
745 
746 	adev = svm_range_get_adev_by_id(prange, prange->actual_loc);
747 	if (!adev) {
748 		pr_debug("failed to get device by id 0x%x\n",
749 			 prange->actual_loc);
750 		return -ENODEV;
751 	}
752 
753 	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] from gpu 0x%x to ram\n",
754 		 prange->svms, prange, prange->start, prange->last,
755 		 prange->actual_loc);
756 
757 	start = prange->start << PAGE_SHIFT;
758 	end = (prange->last + 1) << PAGE_SHIFT;
759 
760 	for (addr = start; addr < end;) {
761 		unsigned long next;
762 
763 		vma = find_vma(mm, addr);
764 		if (!vma || addr < vma->vm_start)
765 			break;
766 
767 		next = min(vma->vm_end, end);
768 		r = svm_migrate_vma_to_ram(adev, prange, vma, addr, next);
769 		if (r < 0) {
770 			pr_debug("failed %ld to migrate\n", r);
771 			break;
772 		} else {
773 			upages += r;
774 		}
775 		addr = next;
776 	}
777 
778 	if (!upages) {
779 		svm_range_vram_node_free(prange);
780 		prange->actual_loc = 0;
781 	}
782 
783 	return r < 0 ? r : 0;
784 }
785 
786 /**
787  * svm_migrate_vram_to_vram - migrate svm range from device to device
788  * @prange: range structure
789  * @best_loc: the device to migrate to
790  * @mm: process mm, use current->mm if NULL
791  *
792  * Context: Process context, caller hold mmap read lock, svms lock, prange lock
793  *
794  * Return:
795  * 0 - OK, otherwise error code
796  */
797 static int
798 svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
799 			 struct mm_struct *mm)
800 {
801 	int r, retries = 3;
802 
803 	/*
804 	 * TODO: for both devices with PCIe large bar or on same xgmi hive, skip
805 	 * system memory as migration bridge
806 	 */
807 
808 	pr_debug("from gpu 0x%x to gpu 0x%x\n", prange->actual_loc, best_loc);
809 
810 	do {
811 		r = svm_migrate_vram_to_ram(prange, mm);
812 		if (r)
813 			return r;
814 	} while (prange->actual_loc && --retries);
815 
816 	if (prange->actual_loc)
817 		return -EDEADLK;
818 
819 	return svm_migrate_ram_to_vram(prange, best_loc, mm);
820 }
821 
822 int
823 svm_migrate_to_vram(struct svm_range *prange, uint32_t best_loc,
824 		    struct mm_struct *mm)
825 {
826 	if  (!prange->actual_loc)
827 		return svm_migrate_ram_to_vram(prange, best_loc, mm);
828 	else
829 		return svm_migrate_vram_to_vram(prange, best_loc, mm);
830 
831 }
832 
833 /**
834  * svm_migrate_to_ram - CPU page fault handler
835  * @vmf: CPU vm fault vma, address
836  *
837  * Context: vm fault handler, caller holds the mmap read lock
838  *
839  * Return:
840  * 0 - OK
841  * VM_FAULT_SIGBUS - notice application to have SIGBUS page fault
842  */
843 static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)
844 {
845 	unsigned long addr = vmf->address;
846 	struct vm_area_struct *vma;
847 	enum svm_work_list_ops op;
848 	struct svm_range *parent;
849 	struct svm_range *prange;
850 	struct kfd_process *p;
851 	struct mm_struct *mm;
852 	int r = 0;
853 
854 	vma = vmf->vma;
855 	mm = vma->vm_mm;
856 
857 	p = kfd_lookup_process_by_mm(vma->vm_mm);
858 	if (!p) {
859 		pr_debug("failed find process at fault address 0x%lx\n", addr);
860 		return VM_FAULT_SIGBUS;
861 	}
862 	if (READ_ONCE(p->svms.faulting_task) == current) {
863 		pr_debug("skipping ram migration\n");
864 		kfd_unref_process(p);
865 		return 0;
866 	}
867 	addr >>= PAGE_SHIFT;
868 	pr_debug("CPU page fault svms 0x%p address 0x%lx\n", &p->svms, addr);
869 
870 	mutex_lock(&p->svms.lock);
871 
872 	prange = svm_range_from_addr(&p->svms, addr, &parent);
873 	if (!prange) {
874 		pr_debug("cannot find svm range at 0x%lx\n", addr);
875 		r = -EFAULT;
876 		goto out;
877 	}
878 
879 	mutex_lock(&parent->migrate_mutex);
880 	if (prange != parent)
881 		mutex_lock_nested(&prange->migrate_mutex, 1);
882 
883 	if (!prange->actual_loc)
884 		goto out_unlock_prange;
885 
886 	svm_range_lock(parent);
887 	if (prange != parent)
888 		mutex_lock_nested(&prange->lock, 1);
889 	r = svm_range_split_by_granularity(p, mm, addr, parent, prange);
890 	if (prange != parent)
891 		mutex_unlock(&prange->lock);
892 	svm_range_unlock(parent);
893 	if (r) {
894 		pr_debug("failed %d to split range by granularity\n", r);
895 		goto out_unlock_prange;
896 	}
897 
898 	r = svm_migrate_vram_to_ram(prange, mm);
899 	if (r)
900 		pr_debug("failed %d migrate 0x%p [0x%lx 0x%lx] to ram\n", r,
901 			 prange, prange->start, prange->last);
902 
903 	/* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
904 	if (p->xnack_enabled && parent == prange)
905 		op = SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP;
906 	else
907 		op = SVM_OP_UPDATE_RANGE_NOTIFIER;
908 	svm_range_add_list_work(&p->svms, parent, mm, op);
909 	schedule_deferred_list_work(&p->svms);
910 
911 out_unlock_prange:
912 	if (prange != parent)
913 		mutex_unlock(&prange->migrate_mutex);
914 	mutex_unlock(&parent->migrate_mutex);
915 out:
916 	mutex_unlock(&p->svms.lock);
917 	kfd_unref_process(p);
918 
919 	pr_debug("CPU fault svms 0x%p address 0x%lx done\n", &p->svms, addr);
920 
921 	return r ? VM_FAULT_SIGBUS : 0;
922 }
923 
924 static const struct dev_pagemap_ops svm_migrate_pgmap_ops = {
925 	.page_free		= svm_migrate_page_free,
926 	.migrate_to_ram		= svm_migrate_to_ram,
927 };
928 
929 /* Each VRAM page uses sizeof(struct page) on system memory */
930 #define SVM_HMM_PAGE_STRUCT_SIZE(size) ((size)/PAGE_SIZE * sizeof(struct page))
931 
932 int svm_migrate_init(struct amdgpu_device *adev)
933 {
934 	struct kfd_dev *kfddev = adev->kfd.dev;
935 	struct dev_pagemap *pgmap;
936 	struct resource *res;
937 	unsigned long size;
938 	void *r;
939 
940 	/* Page migration works on Vega10 or newer */
941 	if (kfddev->device_info->asic_family < CHIP_VEGA10)
942 		return -EINVAL;
943 
944 	pgmap = &kfddev->pgmap;
945 	memset(pgmap, 0, sizeof(*pgmap));
946 
947 	/* TODO: register all vram to HMM for now.
948 	 * should remove reserved size
949 	 */
950 	size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
951 	res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
952 	if (IS_ERR(res))
953 		return -ENOMEM;
954 
955 	pgmap->type = MEMORY_DEVICE_PRIVATE;
956 	pgmap->nr_range = 1;
957 	pgmap->range.start = res->start;
958 	pgmap->range.end = res->end;
959 	pgmap->ops = &svm_migrate_pgmap_ops;
960 	pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
961 	pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
962 
963 	/* Device manager releases device-specific resources, memory region and
964 	 * pgmap when driver disconnects from device.
965 	 */
966 	r = devm_memremap_pages(adev->dev, pgmap);
967 	if (IS_ERR(r)) {
968 		pr_err("failed to register HMM device memory\n");
969 
970 		/* Disable SVM support capability */
971 		pgmap->type = 0;
972 		devm_release_mem_region(adev->dev, res->start, resource_size(res));
973 		return PTR_ERR(r);
974 	}
975 
976 	pr_debug("reserve %ldMB system memory for VRAM pages struct\n",
977 		 SVM_HMM_PAGE_STRUCT_SIZE(size) >> 20);
978 
979 	amdgpu_amdkfd_reserve_system_mem(SVM_HMM_PAGE_STRUCT_SIZE(size));
980 
981 	pr_info("HMM registered %ldMB device memory\n", size >> 20);
982 
983 	return 0;
984 }
985