xref: /linux/drivers/gpu/drm/xe/xe_svm.c (revision 1b5d39e6672fdee158c3306f5cb2df8975c77e5a)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2024 Intel Corporation
4  */
5 
6 #include <drm/drm_drv.h>
7 
8 #include "xe_bo.h"
9 #include "xe_exec_queue_types.h"
10 #include "xe_gt_stats.h"
11 #include "xe_migrate.h"
12 #include "xe_module.h"
13 #include "xe_pm.h"
14 #include "xe_pt.h"
15 #include "xe_svm.h"
16 #include "xe_tile.h"
17 #include "xe_ttm_vram_mgr.h"
18 #include "xe_vm.h"
19 #include "xe_vm_types.h"
20 #include "xe_vram_types.h"
21 
22 static bool xe_svm_range_in_vram(struct xe_svm_range *range)
23 {
24 	/*
25 	 * Advisory only check whether the range is currently backed by VRAM
26 	 * memory.
27 	 */
28 
29 	struct drm_gpusvm_pages_flags flags = {
30 		/* Pairs with WRITE_ONCE in drm_gpusvm.c */
31 		.__flags = READ_ONCE(range->base.pages.flags.__flags),
32 	};
33 
34 	return flags.has_devmem_pages;
35 }
36 
37 static bool xe_svm_range_has_vram_binding(struct xe_svm_range *range)
38 {
39 	/* Not reliable without notifier lock */
40 	return xe_svm_range_in_vram(range) && range->tile_present;
41 }
42 
43 static struct xe_vm *gpusvm_to_vm(struct drm_gpusvm *gpusvm)
44 {
45 	return container_of(gpusvm, struct xe_vm, svm.gpusvm);
46 }
47 
48 static struct xe_vm *range_to_vm(struct drm_gpusvm_range *r)
49 {
50 	return gpusvm_to_vm(r->gpusvm);
51 }
52 
53 #define range_debug(r__, operation__)					\
54 	vm_dbg(&range_to_vm(&(r__)->base)->xe->drm,			\
55 	       "%s: asid=%u, gpusvm=%p, vram=%d,%d, seqno=%lu, " \
56 	       "start=0x%014lx, end=0x%014lx, size=%lu",		\
57 	       (operation__), range_to_vm(&(r__)->base)->usm.asid,	\
58 	       (r__)->base.gpusvm,					\
59 	       xe_svm_range_in_vram((r__)) ? 1 : 0,			\
60 	       xe_svm_range_has_vram_binding((r__)) ? 1 : 0,		\
61 	       (r__)->base.pages.notifier_seq,				\
62 	       xe_svm_range_start((r__)), xe_svm_range_end((r__)),	\
63 	       xe_svm_range_size((r__)))
64 
65 void xe_svm_range_debug(struct xe_svm_range *range, const char *operation)
66 {
67 	range_debug(range, operation);
68 }
69 
70 static struct drm_gpusvm_range *
71 xe_svm_range_alloc(struct drm_gpusvm *gpusvm)
72 {
73 	struct xe_svm_range *range;
74 
75 	range = kzalloc(sizeof(*range), GFP_KERNEL);
76 	if (!range)
77 		return NULL;
78 
79 	INIT_LIST_HEAD(&range->garbage_collector_link);
80 	xe_vm_get(gpusvm_to_vm(gpusvm));
81 
82 	return &range->base;
83 }
84 
85 static void xe_svm_range_free(struct drm_gpusvm_range *range)
86 {
87 	xe_vm_put(range_to_vm(range));
88 	kfree(range);
89 }
90 
91 static void
92 xe_svm_garbage_collector_add_range(struct xe_vm *vm, struct xe_svm_range *range,
93 				   const struct mmu_notifier_range *mmu_range)
94 {
95 	struct xe_device *xe = vm->xe;
96 
97 	range_debug(range, "GARBAGE COLLECTOR ADD");
98 
99 	drm_gpusvm_range_set_unmapped(&range->base, mmu_range);
100 
101 	spin_lock(&vm->svm.garbage_collector.lock);
102 	if (list_empty(&range->garbage_collector_link))
103 		list_add_tail(&range->garbage_collector_link,
104 			      &vm->svm.garbage_collector.range_list);
105 	spin_unlock(&vm->svm.garbage_collector.lock);
106 
107 	queue_work(xe->usm.pf_wq, &vm->svm.garbage_collector.work);
108 }
109 
110 static void xe_svm_tlb_inval_count_stats_incr(struct xe_gt *gt)
111 {
112 	xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_TLB_INVAL_COUNT, 1);
113 }
114 
115 static u8
116 xe_svm_range_notifier_event_begin(struct xe_vm *vm, struct drm_gpusvm_range *r,
117 				  const struct mmu_notifier_range *mmu_range,
118 				  u64 *adj_start, u64 *adj_end)
119 {
120 	struct xe_svm_range *range = to_xe_range(r);
121 	struct xe_device *xe = vm->xe;
122 	struct xe_tile *tile;
123 	u8 tile_mask = 0;
124 	u8 id;
125 
126 	xe_svm_assert_in_notifier(vm);
127 
128 	range_debug(range, "NOTIFIER");
129 
130 	/* Skip if already unmapped or if no binding exist */
131 	if (range->base.pages.flags.unmapped || !range->tile_present)
132 		return 0;
133 
134 	range_debug(range, "NOTIFIER - EXECUTE");
135 
136 	/* Adjust invalidation to range boundaries */
137 	*adj_start = min(xe_svm_range_start(range), mmu_range->start);
138 	*adj_end = max(xe_svm_range_end(range), mmu_range->end);
139 
140 	/*
141 	 * XXX: Ideally would zap PTEs in one shot in xe_svm_invalidate but the
142 	 * invalidation code can't correctly cope with sparse ranges or
143 	 * invalidations spanning multiple ranges.
144 	 */
145 	for_each_tile(tile, xe, id)
146 		if (xe_pt_zap_ptes_range(tile, vm, range)) {
147 			/*
148 			 * WRITE_ONCE pairs with READ_ONCE in
149 			 * xe_vm_has_valid_gpu_mapping()
150 			 */
151 			WRITE_ONCE(range->tile_invalidated,
152 				   range->tile_invalidated | BIT(id));
153 
154 			if (!(tile_mask & BIT(id))) {
155 				xe_svm_tlb_inval_count_stats_incr(tile->primary_gt);
156 				if (tile->media_gt)
157 					xe_svm_tlb_inval_count_stats_incr(tile->media_gt);
158 				tile_mask |= BIT(id);
159 			}
160 		}
161 
162 	return tile_mask;
163 }
164 
165 static void
166 xe_svm_range_notifier_event_end(struct xe_vm *vm, struct drm_gpusvm_range *r,
167 				const struct mmu_notifier_range *mmu_range)
168 {
169 	struct drm_gpusvm_ctx ctx = { .in_notifier = true, };
170 
171 	xe_svm_assert_in_notifier(vm);
172 
173 	drm_gpusvm_range_unmap_pages(&vm->svm.gpusvm, r, &ctx);
174 	if (!xe_vm_is_closed(vm) && mmu_range->event == MMU_NOTIFY_UNMAP)
175 		xe_svm_garbage_collector_add_range(vm, to_xe_range(r),
176 						   mmu_range);
177 }
178 
179 static s64 xe_svm_stats_ktime_us_delta(ktime_t start)
180 {
181 	return IS_ENABLED(CONFIG_DEBUG_FS) ?
182 		ktime_us_delta(ktime_get(), start) : 0;
183 }
184 
185 static void xe_svm_tlb_inval_us_stats_incr(struct xe_gt *gt, ktime_t start)
186 {
187 	s64 us_delta = xe_svm_stats_ktime_us_delta(start);
188 
189 	xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_TLB_INVAL_US, us_delta);
190 }
191 
192 static ktime_t xe_svm_stats_ktime_get(void)
193 {
194 	return IS_ENABLED(CONFIG_DEBUG_FS) ? ktime_get() : 0;
195 }
196 
197 static void xe_svm_invalidate(struct drm_gpusvm *gpusvm,
198 			      struct drm_gpusvm_notifier *notifier,
199 			      const struct mmu_notifier_range *mmu_range)
200 {
201 	struct xe_vm *vm = gpusvm_to_vm(gpusvm);
202 	struct xe_device *xe = vm->xe;
203 	struct drm_gpusvm_range *r, *first;
204 	struct xe_tile *tile;
205 	ktime_t start = xe_svm_stats_ktime_get();
206 	u64 adj_start = mmu_range->start, adj_end = mmu_range->end;
207 	u8 tile_mask = 0, id;
208 	long err;
209 
210 	xe_svm_assert_in_notifier(vm);
211 
212 	vm_dbg(&gpusvm_to_vm(gpusvm)->xe->drm,
213 	       "INVALIDATE: asid=%u, gpusvm=%p, seqno=%lu, start=0x%016lx, end=0x%016lx, event=%d",
214 	       vm->usm.asid, gpusvm, notifier->notifier.invalidate_seq,
215 	       mmu_range->start, mmu_range->end, mmu_range->event);
216 
217 	/* Adjust invalidation to notifier boundaries */
218 	adj_start = max(drm_gpusvm_notifier_start(notifier), adj_start);
219 	adj_end = min(drm_gpusvm_notifier_end(notifier), adj_end);
220 
221 	first = drm_gpusvm_range_find(notifier, adj_start, adj_end);
222 	if (!first)
223 		return;
224 
225 	/*
226 	 * PTs may be getting destroyed so not safe to touch these but PT should
227 	 * be invalidated at this point in time. Regardless we still need to
228 	 * ensure any dma mappings are unmapped in the here.
229 	 */
230 	if (xe_vm_is_closed(vm))
231 		goto range_notifier_event_end;
232 
233 	/*
234 	 * XXX: Less than ideal to always wait on VM's resv slots if an
235 	 * invalidation is not required. Could walk range list twice to figure
236 	 * out if an invalidations is need, but also not ideal.
237 	 */
238 	err = dma_resv_wait_timeout(xe_vm_resv(vm),
239 				    DMA_RESV_USAGE_BOOKKEEP,
240 				    false, MAX_SCHEDULE_TIMEOUT);
241 	XE_WARN_ON(err <= 0);
242 
243 	r = first;
244 	drm_gpusvm_for_each_range(r, notifier, adj_start, adj_end)
245 		tile_mask |= xe_svm_range_notifier_event_begin(vm, r, mmu_range,
246 							       &adj_start,
247 							       &adj_end);
248 	if (!tile_mask)
249 		goto range_notifier_event_end;
250 
251 	xe_device_wmb(xe);
252 
253 	err = xe_vm_range_tilemask_tlb_inval(vm, adj_start, adj_end, tile_mask);
254 	WARN_ON_ONCE(err);
255 
256 range_notifier_event_end:
257 	r = first;
258 	drm_gpusvm_for_each_range(r, notifier, adj_start, adj_end)
259 		xe_svm_range_notifier_event_end(vm, r, mmu_range);
260 	for_each_tile(tile, xe, id) {
261 		if (tile_mask & BIT(id)) {
262 			xe_svm_tlb_inval_us_stats_incr(tile->primary_gt, start);
263 			if (tile->media_gt)
264 				xe_svm_tlb_inval_us_stats_incr(tile->media_gt, start);
265 		}
266 	}
267 }
268 
269 static int __xe_svm_garbage_collector(struct xe_vm *vm,
270 				      struct xe_svm_range *range)
271 {
272 	struct dma_fence *fence;
273 
274 	range_debug(range, "GARBAGE COLLECTOR");
275 
276 	xe_vm_lock(vm, false);
277 	fence = xe_vm_range_unbind(vm, range);
278 	xe_vm_unlock(vm);
279 	if (IS_ERR(fence))
280 		return PTR_ERR(fence);
281 	dma_fence_put(fence);
282 
283 	drm_gpusvm_range_remove(&vm->svm.gpusvm, &range->base);
284 
285 	return 0;
286 }
287 
288 static void xe_vma_set_default_attributes(struct xe_vma *vma)
289 {
290 	vma->attr.preferred_loc.devmem_fd = DRM_XE_PREFERRED_LOC_DEFAULT_DEVICE;
291 	vma->attr.preferred_loc.migration_policy = DRM_XE_MIGRATE_ALL_PAGES;
292 	vma->attr.pat_index = vma->attr.default_pat_index;
293 	vma->attr.atomic_access = DRM_XE_ATOMIC_UNDEFINED;
294 }
295 
296 static int xe_svm_range_set_default_attr(struct xe_vm *vm, u64 start, u64 end)
297 {
298 	struct xe_vma *vma;
299 	bool has_default_attr;
300 	int err;
301 
302 	vma = xe_vm_find_vma_by_addr(vm, start);
303 	if (!vma)
304 		return -EINVAL;
305 
306 	if (!(vma->gpuva.flags & XE_VMA_MADV_AUTORESET)) {
307 		drm_dbg(&vm->xe->drm, "Skipping madvise reset for vma.\n");
308 		return 0;
309 	}
310 
311 	vm_dbg(&vm->xe->drm, "Existing VMA start=0x%016llx, vma_end=0x%016llx",
312 	       xe_vma_start(vma), xe_vma_end(vma));
313 
314 	has_default_attr = xe_vma_has_default_mem_attrs(vma);
315 
316 	if (has_default_attr) {
317 		start = xe_vma_start(vma);
318 		end = xe_vma_end(vma);
319 	} else if (xe_vma_start(vma) == start && xe_vma_end(vma) == end) {
320 		xe_vma_set_default_attributes(vma);
321 	}
322 
323 	xe_vm_find_cpu_addr_mirror_vma_range(vm, &start, &end);
324 
325 	if (xe_vma_start(vma) == start && xe_vma_end(vma) == end && has_default_attr)
326 		return 0;
327 
328 	vm_dbg(&vm->xe->drm, "New VMA start=0x%016llx, vma_end=0x%016llx",  start, end);
329 
330 	err = xe_vm_alloc_cpu_addr_mirror_vma(vm, start, end - start);
331 	if (err) {
332 		drm_warn(&vm->xe->drm, "New VMA MAP failed: %pe\n", ERR_PTR(err));
333 		xe_vm_kill(vm, true);
334 		return err;
335 	}
336 
337 	/*
338 	 * On call from xe_svm_handle_pagefault original VMA might be changed
339 	 * signal this to lookup for VMA again.
340 	 */
341 	return -EAGAIN;
342 }
343 
344 static int xe_svm_garbage_collector(struct xe_vm *vm)
345 {
346 	struct xe_svm_range *range;
347 	u64 range_start;
348 	u64 range_end;
349 	int err, ret = 0;
350 
351 	lockdep_assert_held_write(&vm->lock);
352 
353 	if (xe_vm_is_closed_or_banned(vm))
354 		return -ENOENT;
355 
356 	for (;;) {
357 		spin_lock(&vm->svm.garbage_collector.lock);
358 		range = list_first_entry_or_null(&vm->svm.garbage_collector.range_list,
359 						 typeof(*range),
360 						 garbage_collector_link);
361 		if (!range)
362 			break;
363 
364 		range_start = xe_svm_range_start(range);
365 		range_end = xe_svm_range_end(range);
366 
367 		list_del(&range->garbage_collector_link);
368 		spin_unlock(&vm->svm.garbage_collector.lock);
369 
370 		err = __xe_svm_garbage_collector(vm, range);
371 		if (err) {
372 			drm_warn(&vm->xe->drm,
373 				 "Garbage collection failed: %pe\n",
374 				 ERR_PTR(err));
375 			xe_vm_kill(vm, true);
376 			return err;
377 		}
378 
379 		err = xe_svm_range_set_default_attr(vm, range_start, range_end);
380 		if (err) {
381 			if (err == -EAGAIN)
382 				ret = -EAGAIN;
383 			else
384 				return err;
385 		}
386 	}
387 	spin_unlock(&vm->svm.garbage_collector.lock);
388 
389 	return ret;
390 }
391 
392 static void xe_svm_garbage_collector_work_func(struct work_struct *w)
393 {
394 	struct xe_vm *vm = container_of(w, struct xe_vm,
395 					svm.garbage_collector.work);
396 
397 	down_write(&vm->lock);
398 	xe_svm_garbage_collector(vm);
399 	up_write(&vm->lock);
400 }
401 
402 #if IS_ENABLED(CONFIG_DRM_XE_PAGEMAP)
403 
404 static struct xe_vram_region *page_to_vr(struct page *page)
405 {
406 	return container_of(page_pgmap(page), struct xe_vram_region, pagemap);
407 }
408 
409 static u64 xe_vram_region_page_to_dpa(struct xe_vram_region *vr,
410 				      struct page *page)
411 {
412 	u64 dpa;
413 	u64 pfn = page_to_pfn(page);
414 	u64 offset;
415 
416 	xe_assert(vr->xe, is_device_private_page(page));
417 	xe_assert(vr->xe, (pfn << PAGE_SHIFT) >= vr->hpa_base);
418 
419 	offset = (pfn << PAGE_SHIFT) - vr->hpa_base;
420 	dpa = vr->dpa_base + offset;
421 
422 	return dpa;
423 }
424 
425 enum xe_svm_copy_dir {
426 	XE_SVM_COPY_TO_VRAM,
427 	XE_SVM_COPY_TO_SRAM,
428 };
429 
430 static void xe_svm_copy_kb_stats_incr(struct xe_gt *gt,
431 				      const enum xe_svm_copy_dir dir,
432 				      int kb)
433 {
434 	if (dir == XE_SVM_COPY_TO_VRAM)
435 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_DEVICE_COPY_KB, kb);
436 	else
437 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_CPU_COPY_KB, kb);
438 }
439 
440 static void xe_svm_copy_us_stats_incr(struct xe_gt *gt,
441 				      const enum xe_svm_copy_dir dir,
442 				      unsigned long npages,
443 				      ktime_t start)
444 {
445 	s64 us_delta = xe_svm_stats_ktime_us_delta(start);
446 
447 	if (dir == XE_SVM_COPY_TO_VRAM) {
448 		switch (npages) {
449 		case 1:
450 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_4K_DEVICE_COPY_US,
451 					 us_delta);
452 			break;
453 		case 16:
454 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_64K_DEVICE_COPY_US,
455 					 us_delta);
456 			break;
457 		case 512:
458 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_2M_DEVICE_COPY_US,
459 					 us_delta);
460 			break;
461 		}
462 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_DEVICE_COPY_US,
463 				 us_delta);
464 	} else {
465 		switch (npages) {
466 		case 1:
467 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_4K_CPU_COPY_US,
468 					 us_delta);
469 			break;
470 		case 16:
471 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_64K_CPU_COPY_US,
472 					 us_delta);
473 			break;
474 		case 512:
475 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_2M_CPU_COPY_US,
476 					 us_delta);
477 			break;
478 		}
479 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_CPU_COPY_US,
480 				 us_delta);
481 	}
482 }
483 
484 static int xe_svm_copy(struct page **pages,
485 		       struct drm_pagemap_addr *pagemap_addr,
486 		       unsigned long npages, const enum xe_svm_copy_dir dir)
487 {
488 	struct xe_vram_region *vr = NULL;
489 	struct xe_gt *gt = NULL;
490 	struct xe_device *xe;
491 	struct dma_fence *fence = NULL;
492 	unsigned long i;
493 #define XE_VRAM_ADDR_INVALID	~0x0ull
494 	u64 vram_addr = XE_VRAM_ADDR_INVALID;
495 	int err = 0, pos = 0;
496 	bool sram = dir == XE_SVM_COPY_TO_SRAM;
497 	ktime_t start = xe_svm_stats_ktime_get();
498 
499 	/*
500 	 * This flow is complex: it locates physically contiguous device pages,
501 	 * derives the starting physical address, and performs a single GPU copy
502 	 * to for every 8M chunk in a DMA address array. Both device pages and
503 	 * DMA addresses may be sparsely populated. If either is NULL, a copy is
504 	 * triggered based on the current search state. The last GPU copy is
505 	 * waited on to ensure all copies are complete.
506 	 */
507 
508 	for (i = 0; i < npages; ++i) {
509 		struct page *spage = pages[i];
510 		struct dma_fence *__fence;
511 		u64 __vram_addr;
512 		bool match = false, chunk, last;
513 
514 #define XE_MIGRATE_CHUNK_SIZE	SZ_8M
515 		chunk = (i - pos) == (XE_MIGRATE_CHUNK_SIZE / PAGE_SIZE);
516 		last = (i + 1) == npages;
517 
518 		/* No CPU page and no device pages queue'd to copy */
519 		if (!pagemap_addr[i].addr && vram_addr == XE_VRAM_ADDR_INVALID)
520 			continue;
521 
522 		if (!vr && spage) {
523 			vr = page_to_vr(spage);
524 			gt = xe_migrate_exec_queue(vr->migrate)->gt;
525 			xe = vr->xe;
526 		}
527 		XE_WARN_ON(spage && page_to_vr(spage) != vr);
528 
529 		/*
530 		 * CPU page and device page valid, capture physical address on
531 		 * first device page, check if physical contiguous on subsequent
532 		 * device pages.
533 		 */
534 		if (pagemap_addr[i].addr && spage) {
535 			__vram_addr = xe_vram_region_page_to_dpa(vr, spage);
536 			if (vram_addr == XE_VRAM_ADDR_INVALID) {
537 				vram_addr = __vram_addr;
538 				pos = i;
539 			}
540 
541 			match = vram_addr + PAGE_SIZE * (i - pos) == __vram_addr;
542 			/* Expected with contiguous memory */
543 			xe_assert(vr->xe, match);
544 
545 			if (pagemap_addr[i].order) {
546 				i += NR_PAGES(pagemap_addr[i].order) - 1;
547 				chunk = (i - pos) == (XE_MIGRATE_CHUNK_SIZE / PAGE_SIZE);
548 				last = (i + 1) == npages;
549 			}
550 		}
551 
552 		/*
553 		 * Mismatched physical address, 8M copy chunk, or last page -
554 		 * trigger a copy.
555 		 */
556 		if (!match || chunk || last) {
557 			/*
558 			 * Extra page for first copy if last page and matching
559 			 * physical address.
560 			 */
561 			int incr = (match && last) ? 1 : 0;
562 
563 			if (vram_addr != XE_VRAM_ADDR_INVALID) {
564 				xe_svm_copy_kb_stats_incr(gt, dir,
565 							  (i - pos + incr) *
566 							  (PAGE_SIZE / SZ_1K));
567 				if (sram) {
568 					vm_dbg(&xe->drm,
569 					       "COPY TO SRAM - 0x%016llx -> 0x%016llx, NPAGES=%ld",
570 					       vram_addr,
571 					       (u64)pagemap_addr[pos].addr, i - pos + incr);
572 					__fence = xe_migrate_from_vram(vr->migrate,
573 								       i - pos + incr,
574 								       vram_addr,
575 								       &pagemap_addr[pos]);
576 				} else {
577 					vm_dbg(&xe->drm,
578 					       "COPY TO VRAM - 0x%016llx -> 0x%016llx, NPAGES=%ld",
579 					       (u64)pagemap_addr[pos].addr, vram_addr,
580 					       i - pos + incr);
581 					__fence = xe_migrate_to_vram(vr->migrate,
582 								     i - pos + incr,
583 								     &pagemap_addr[pos],
584 								     vram_addr);
585 				}
586 				if (IS_ERR(__fence)) {
587 					err = PTR_ERR(__fence);
588 					goto err_out;
589 				}
590 
591 				dma_fence_put(fence);
592 				fence = __fence;
593 			}
594 
595 			/* Setup physical address of next device page */
596 			if (pagemap_addr[i].addr && spage) {
597 				vram_addr = __vram_addr;
598 				pos = i;
599 			} else {
600 				vram_addr = XE_VRAM_ADDR_INVALID;
601 			}
602 
603 			/* Extra mismatched device page, copy it */
604 			if (!match && last && vram_addr != XE_VRAM_ADDR_INVALID) {
605 				xe_svm_copy_kb_stats_incr(gt, dir,
606 							  (PAGE_SIZE / SZ_1K));
607 				if (sram) {
608 					vm_dbg(&xe->drm,
609 					       "COPY TO SRAM - 0x%016llx -> 0x%016llx, NPAGES=%d",
610 					       vram_addr, (u64)pagemap_addr[pos].addr, 1);
611 					__fence = xe_migrate_from_vram(vr->migrate, 1,
612 								       vram_addr,
613 								       &pagemap_addr[pos]);
614 				} else {
615 					vm_dbg(&xe->drm,
616 					       "COPY TO VRAM - 0x%016llx -> 0x%016llx, NPAGES=%d",
617 					       (u64)pagemap_addr[pos].addr, vram_addr, 1);
618 					__fence = xe_migrate_to_vram(vr->migrate, 1,
619 								     &pagemap_addr[pos],
620 								     vram_addr);
621 				}
622 				if (IS_ERR(__fence)) {
623 					err = PTR_ERR(__fence);
624 					goto err_out;
625 				}
626 
627 				dma_fence_put(fence);
628 				fence = __fence;
629 			}
630 		}
631 	}
632 
633 err_out:
634 	/* Wait for all copies to complete */
635 	if (fence) {
636 		dma_fence_wait(fence, false);
637 		dma_fence_put(fence);
638 	}
639 
640 	/*
641 	 * XXX: We can't derive the GT here (or anywhere in this functions, but
642 	 * compute always uses the primary GT so accumulate stats on the likely
643 	 * GT of the fault.
644 	 */
645 	if (gt)
646 		xe_svm_copy_us_stats_incr(gt, dir, npages, start);
647 
648 	return err;
649 #undef XE_MIGRATE_CHUNK_SIZE
650 #undef XE_VRAM_ADDR_INVALID
651 }
652 
653 static int xe_svm_copy_to_devmem(struct page **pages,
654 				 struct drm_pagemap_addr *pagemap_addr,
655 				 unsigned long npages)
656 {
657 	return xe_svm_copy(pages, pagemap_addr, npages, XE_SVM_COPY_TO_VRAM);
658 }
659 
660 static int xe_svm_copy_to_ram(struct page **pages,
661 			      struct drm_pagemap_addr *pagemap_addr,
662 			      unsigned long npages)
663 {
664 	return xe_svm_copy(pages, pagemap_addr, npages, XE_SVM_COPY_TO_SRAM);
665 }
666 
667 static struct xe_bo *to_xe_bo(struct drm_pagemap_devmem *devmem_allocation)
668 {
669 	return container_of(devmem_allocation, struct xe_bo, devmem_allocation);
670 }
671 
672 static void xe_svm_devmem_release(struct drm_pagemap_devmem *devmem_allocation)
673 {
674 	struct xe_bo *bo = to_xe_bo(devmem_allocation);
675 	struct xe_device *xe = xe_bo_device(bo);
676 
677 	xe_bo_put_async(bo);
678 	xe_pm_runtime_put(xe);
679 }
680 
681 static u64 block_offset_to_pfn(struct xe_vram_region *vr, u64 offset)
682 {
683 	return PHYS_PFN(offset + vr->hpa_base);
684 }
685 
686 static struct drm_buddy *vram_to_buddy(struct xe_vram_region *vram)
687 {
688 	return &vram->ttm.mm;
689 }
690 
691 static int xe_svm_populate_devmem_pfn(struct drm_pagemap_devmem *devmem_allocation,
692 				      unsigned long npages, unsigned long *pfn)
693 {
694 	struct xe_bo *bo = to_xe_bo(devmem_allocation);
695 	struct ttm_resource *res = bo->ttm.resource;
696 	struct list_head *blocks = &to_xe_ttm_vram_mgr_resource(res)->blocks;
697 	struct drm_buddy_block *block;
698 	int j = 0;
699 
700 	list_for_each_entry(block, blocks, link) {
701 		struct xe_vram_region *vr = block->private;
702 		struct drm_buddy *buddy = vram_to_buddy(vr);
703 		u64 block_pfn = block_offset_to_pfn(vr, drm_buddy_block_offset(block));
704 		int i;
705 
706 		for (i = 0; i < drm_buddy_block_size(buddy, block) >> PAGE_SHIFT; ++i)
707 			pfn[j++] = block_pfn + i;
708 	}
709 
710 	return 0;
711 }
712 
713 static const struct drm_pagemap_devmem_ops dpagemap_devmem_ops = {
714 	.devmem_release = xe_svm_devmem_release,
715 	.populate_devmem_pfn = xe_svm_populate_devmem_pfn,
716 	.copy_to_devmem = xe_svm_copy_to_devmem,
717 	.copy_to_ram = xe_svm_copy_to_ram,
718 };
719 
720 #endif
721 
722 static const struct drm_gpusvm_ops gpusvm_ops = {
723 	.range_alloc = xe_svm_range_alloc,
724 	.range_free = xe_svm_range_free,
725 	.invalidate = xe_svm_invalidate,
726 };
727 
728 static const unsigned long fault_chunk_sizes[] = {
729 	SZ_2M,
730 	SZ_64K,
731 	SZ_4K,
732 };
733 
734 /**
735  * xe_svm_init() - SVM initialize
736  * @vm: The VM.
737  *
738  * Initialize SVM state which is embedded within the VM.
739  *
740  * Return: 0 on success, negative error code on error.
741  */
742 int xe_svm_init(struct xe_vm *vm)
743 {
744 	int err;
745 
746 	if (vm->flags & XE_VM_FLAG_FAULT_MODE) {
747 		spin_lock_init(&vm->svm.garbage_collector.lock);
748 		INIT_LIST_HEAD(&vm->svm.garbage_collector.range_list);
749 		INIT_WORK(&vm->svm.garbage_collector.work,
750 			  xe_svm_garbage_collector_work_func);
751 
752 		err = drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM", &vm->xe->drm,
753 				      current->mm, 0, vm->size,
754 				      xe_modparam.svm_notifier_size * SZ_1M,
755 				      &gpusvm_ops, fault_chunk_sizes,
756 				      ARRAY_SIZE(fault_chunk_sizes));
757 		drm_gpusvm_driver_set_lock(&vm->svm.gpusvm, &vm->lock);
758 	} else {
759 		err = drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM (simple)",
760 				      &vm->xe->drm, NULL, 0, 0, 0, NULL,
761 				      NULL, 0);
762 	}
763 
764 	return err;
765 }
766 
767 /**
768  * xe_svm_close() - SVM close
769  * @vm: The VM.
770  *
771  * Close SVM state (i.e., stop and flush all SVM actions).
772  */
773 void xe_svm_close(struct xe_vm *vm)
774 {
775 	xe_assert(vm->xe, xe_vm_is_closed(vm));
776 	flush_work(&vm->svm.garbage_collector.work);
777 }
778 
779 /**
780  * xe_svm_fini() - SVM finalize
781  * @vm: The VM.
782  *
783  * Finalize SVM state which is embedded within the VM.
784  */
785 void xe_svm_fini(struct xe_vm *vm)
786 {
787 	xe_assert(vm->xe, xe_vm_is_closed(vm));
788 
789 	drm_gpusvm_fini(&vm->svm.gpusvm);
790 }
791 
792 static bool xe_svm_range_is_valid(struct xe_svm_range *range,
793 				  struct xe_tile *tile,
794 				  bool devmem_only)
795 {
796 	return (xe_vm_has_valid_gpu_mapping(tile, range->tile_present,
797 					    range->tile_invalidated) &&
798 		(!devmem_only || xe_svm_range_in_vram(range)));
799 }
800 
801 /** xe_svm_range_migrate_to_smem() - Move range pages from VRAM to SMEM
802  * @vm: xe_vm pointer
803  * @range: Pointer to the SVM range structure
804  *
805  * The xe_svm_range_migrate_to_smem() checks range has pages in VRAM
806  * and migrates them to SMEM
807  */
808 void xe_svm_range_migrate_to_smem(struct xe_vm *vm, struct xe_svm_range *range)
809 {
810 	if (xe_svm_range_in_vram(range))
811 		drm_gpusvm_range_evict(&vm->svm.gpusvm, &range->base);
812 }
813 
814 /**
815  * xe_svm_range_validate() - Check if the SVM range is valid
816  * @vm: xe_vm pointer
817  * @range: Pointer to the SVM range structure
818  * @tile_mask: Mask representing the tiles to be checked
819  * @devmem_preferred : if true range needs to be in devmem
820  *
821  * The xe_svm_range_validate() function checks if a range is
822  * valid and located in the desired memory region.
823  *
824  * Return: true if the range is valid, false otherwise
825  */
826 bool xe_svm_range_validate(struct xe_vm *vm,
827 			   struct xe_svm_range *range,
828 			   u8 tile_mask, bool devmem_preferred)
829 {
830 	bool ret;
831 
832 	xe_svm_notifier_lock(vm);
833 
834 	ret = (range->tile_present & ~range->tile_invalidated & tile_mask) == tile_mask &&
835 	       (devmem_preferred == range->base.pages.flags.has_devmem_pages);
836 
837 	xe_svm_notifier_unlock(vm);
838 
839 	return ret;
840 }
841 
842 /**
843  * xe_svm_find_vma_start - Find start of CPU VMA
844  * @vm: xe_vm pointer
845  * @start: start address
846  * @end: end address
847  * @vma: Pointer to struct xe_vma
848  *
849  *
850  * This function searches for a cpu vma, within the specified
851  * range [start, end] in the given VM. It adjusts the range based on the
852  * xe_vma start and end addresses. If no cpu VMA is found, it returns ULONG_MAX.
853  *
854  * Return: The starting address of the VMA within the range,
855  * or ULONG_MAX if no VMA is found
856  */
857 u64 xe_svm_find_vma_start(struct xe_vm *vm, u64 start, u64 end, struct xe_vma *vma)
858 {
859 	return drm_gpusvm_find_vma_start(&vm->svm.gpusvm,
860 					 max(start, xe_vma_start(vma)),
861 					 min(end, xe_vma_end(vma)));
862 }
863 
864 #if IS_ENABLED(CONFIG_DRM_XE_PAGEMAP)
865 static int xe_drm_pagemap_populate_mm(struct drm_pagemap *dpagemap,
866 				      unsigned long start, unsigned long end,
867 				      struct mm_struct *mm,
868 				      unsigned long timeslice_ms)
869 {
870 	struct xe_vram_region *vr = container_of(dpagemap, typeof(*vr), dpagemap);
871 	struct xe_device *xe = vr->xe;
872 	struct device *dev = xe->drm.dev;
873 	struct drm_buddy_block *block;
874 	struct xe_validation_ctx vctx;
875 	struct list_head *blocks;
876 	struct drm_exec exec;
877 	struct xe_bo *bo;
878 	int err = 0, idx;
879 
880 	if (!drm_dev_enter(&xe->drm, &idx))
881 		return -ENODEV;
882 
883 	xe_pm_runtime_get(xe);
884 
885 	xe_validation_guard(&vctx, &xe->val, &exec, (struct xe_val_flags) {}, err) {
886 		bo = xe_bo_create_locked(xe, NULL, NULL, end - start,
887 					 ttm_bo_type_device,
888 					 (IS_DGFX(xe) ? XE_BO_FLAG_VRAM(vr) : XE_BO_FLAG_SYSTEM) |
889 					 XE_BO_FLAG_CPU_ADDR_MIRROR, &exec);
890 		drm_exec_retry_on_contention(&exec);
891 		if (IS_ERR(bo)) {
892 			err = PTR_ERR(bo);
893 			xe_validation_retry_on_oom(&vctx, &err);
894 			break;
895 		}
896 
897 		drm_pagemap_devmem_init(&bo->devmem_allocation, dev, mm,
898 					&dpagemap_devmem_ops, dpagemap, end - start);
899 
900 		blocks = &to_xe_ttm_vram_mgr_resource(bo->ttm.resource)->blocks;
901 		list_for_each_entry(block, blocks, link)
902 			block->private = vr;
903 
904 		xe_bo_get(bo);
905 
906 		/* Ensure the device has a pm ref while there are device pages active. */
907 		xe_pm_runtime_get_noresume(xe);
908 		err = drm_pagemap_migrate_to_devmem(&bo->devmem_allocation, mm,
909 						    start, end, timeslice_ms,
910 						    xe_svm_devm_owner(xe));
911 		if (err)
912 			xe_svm_devmem_release(&bo->devmem_allocation);
913 		xe_bo_unlock(bo);
914 		xe_bo_put(bo);
915 	}
916 	xe_pm_runtime_put(xe);
917 	drm_dev_exit(idx);
918 
919 	return err;
920 }
921 #endif
922 
923 static bool supports_4K_migration(struct xe_device *xe)
924 {
925 	if (xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K)
926 		return false;
927 
928 	return true;
929 }
930 
931 /**
932  * xe_svm_range_needs_migrate_to_vram() - SVM range needs migrate to VRAM or not
933  * @range: SVM range for which migration needs to be decided
934  * @vma: vma which has range
935  * @preferred_region_is_vram: preferred region for range is vram
936  *
937  * Return: True for range needing migration and migration is supported else false
938  */
939 bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vma *vma,
940 					bool preferred_region_is_vram)
941 {
942 	struct xe_vm *vm = range_to_vm(&range->base);
943 	u64 range_size = xe_svm_range_size(range);
944 
945 	if (!range->base.pages.flags.migrate_devmem || !preferred_region_is_vram)
946 		return false;
947 
948 	xe_assert(vm->xe, IS_DGFX(vm->xe));
949 
950 	if (xe_svm_range_in_vram(range)) {
951 		drm_info(&vm->xe->drm, "Range is already in VRAM\n");
952 		return false;
953 	}
954 
955 	if (range_size < SZ_64K && !supports_4K_migration(vm->xe)) {
956 		drm_dbg(&vm->xe->drm, "Platform doesn't support SZ_4K range migration\n");
957 		return false;
958 	}
959 
960 	return true;
961 }
962 
963 #define DECL_SVM_RANGE_COUNT_STATS(elem, stat) \
964 static void xe_svm_range_##elem##_count_stats_incr(struct xe_gt *gt, \
965 						   struct xe_svm_range *range) \
966 { \
967 	switch (xe_svm_range_size(range)) { \
968 	case SZ_4K: \
969 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_4K_##stat##_COUNT, 1); \
970 		break; \
971 	case SZ_64K: \
972 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_64K_##stat##_COUNT, 1); \
973 		break; \
974 	case SZ_2M: \
975 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_2M_##stat##_COUNT, 1); \
976 		break; \
977 	} \
978 } \
979 
980 DECL_SVM_RANGE_COUNT_STATS(fault, PAGEFAULT)
981 DECL_SVM_RANGE_COUNT_STATS(valid_fault, VALID_PAGEFAULT)
982 DECL_SVM_RANGE_COUNT_STATS(migrate, MIGRATE)
983 
984 #define DECL_SVM_RANGE_US_STATS(elem, stat) \
985 static void xe_svm_range_##elem##_us_stats_incr(struct xe_gt *gt, \
986 						struct xe_svm_range *range, \
987 						ktime_t start) \
988 { \
989 	s64 us_delta = xe_svm_stats_ktime_us_delta(start); \
990 \
991 	switch (xe_svm_range_size(range)) { \
992 	case SZ_4K: \
993 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_4K_##stat##_US, \
994 				 us_delta); \
995 		break; \
996 	case SZ_64K: \
997 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_64K_##stat##_US, \
998 				 us_delta); \
999 		break; \
1000 	case SZ_2M: \
1001 		xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_2M_##stat##_US, \
1002 				 us_delta); \
1003 		break; \
1004 	} \
1005 } \
1006 
1007 DECL_SVM_RANGE_US_STATS(migrate, MIGRATE)
1008 DECL_SVM_RANGE_US_STATS(get_pages, GET_PAGES)
1009 DECL_SVM_RANGE_US_STATS(bind, BIND)
1010 DECL_SVM_RANGE_US_STATS(fault, PAGEFAULT)
1011 
1012 static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
1013 				     struct xe_gt *gt, u64 fault_addr,
1014 				     bool need_vram)
1015 {
1016 	int devmem_possible = IS_DGFX(vm->xe) &&
1017 		IS_ENABLED(CONFIG_DRM_XE_PAGEMAP);
1018 	struct drm_gpusvm_ctx ctx = {
1019 		.read_only = xe_vma_read_only(vma),
1020 		.devmem_possible = devmem_possible,
1021 		.check_pages_threshold = devmem_possible ? SZ_64K : 0,
1022 		.devmem_only = need_vram && devmem_possible,
1023 		.timeslice_ms = need_vram && devmem_possible ?
1024 			vm->xe->atomic_svm_timeslice_ms : 0,
1025 		.device_private_page_owner = xe_svm_devm_owner(vm->xe),
1026 	};
1027 	struct xe_validation_ctx vctx;
1028 	struct drm_exec exec;
1029 	struct xe_svm_range *range;
1030 	struct dma_fence *fence;
1031 	struct drm_pagemap *dpagemap;
1032 	struct xe_tile *tile = gt_to_tile(gt);
1033 	int migrate_try_count = ctx.devmem_only ? 3 : 1;
1034 	ktime_t start = xe_svm_stats_ktime_get(), bind_start, get_pages_start;
1035 	int err;
1036 
1037 	lockdep_assert_held_write(&vm->lock);
1038 	xe_assert(vm->xe, xe_vma_is_cpu_addr_mirror(vma));
1039 
1040 	xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT, 1);
1041 
1042 retry:
1043 	/* Always process UNMAPs first so view SVM ranges is current */
1044 	err = xe_svm_garbage_collector(vm);
1045 	if (err)
1046 		return err;
1047 
1048 	dpagemap = xe_vma_resolve_pagemap(vma, tile);
1049 	if (!dpagemap && !ctx.devmem_only)
1050 		ctx.device_private_page_owner = NULL;
1051 	range = xe_svm_range_find_or_insert(vm, fault_addr, vma, &ctx);
1052 
1053 	if (IS_ERR(range))
1054 		return PTR_ERR(range);
1055 
1056 	xe_svm_range_fault_count_stats_incr(gt, range);
1057 
1058 	if (ctx.devmem_only && !range->base.pages.flags.migrate_devmem) {
1059 		err = -EACCES;
1060 		goto out;
1061 	}
1062 
1063 	if (xe_svm_range_is_valid(range, tile, ctx.devmem_only)) {
1064 		xe_svm_range_valid_fault_count_stats_incr(gt, range);
1065 		range_debug(range, "PAGE FAULT - VALID");
1066 		goto out;
1067 	}
1068 
1069 	range_debug(range, "PAGE FAULT");
1070 
1071 	if (--migrate_try_count >= 0 &&
1072 	    xe_svm_range_needs_migrate_to_vram(range, vma, !!dpagemap || ctx.devmem_only)) {
1073 		ktime_t migrate_start = xe_svm_stats_ktime_get();
1074 
1075 		/* TODO : For multi-device dpagemap will be used to find the
1076 		 * remote tile and remote device. Will need to modify
1077 		 * xe_svm_alloc_vram to use dpagemap for future multi-device
1078 		 * support.
1079 		 */
1080 		xe_svm_range_migrate_count_stats_incr(gt, range);
1081 		err = xe_svm_alloc_vram(tile, range, &ctx);
1082 		xe_svm_range_migrate_us_stats_incr(gt, range, migrate_start);
1083 		ctx.timeslice_ms <<= 1;	/* Double timeslice if we have to retry */
1084 		if (err) {
1085 			if (migrate_try_count || !ctx.devmem_only) {
1086 				drm_dbg(&vm->xe->drm,
1087 					"VRAM allocation failed, falling back to retrying fault, asid=%u, errno=%pe\n",
1088 					vm->usm.asid, ERR_PTR(err));
1089 
1090 				/*
1091 				 * In the devmem-only case, mixed mappings may
1092 				 * be found. The get_pages function will fix
1093 				 * these up to a single location, allowing the
1094 				 * page fault handler to make forward progress.
1095 				 */
1096 				if (ctx.devmem_only)
1097 					goto get_pages;
1098 				else
1099 					goto retry;
1100 			} else {
1101 				drm_err(&vm->xe->drm,
1102 					"VRAM allocation failed, retry count exceeded, asid=%u, errno=%pe\n",
1103 					vm->usm.asid, ERR_PTR(err));
1104 				return err;
1105 			}
1106 		}
1107 	}
1108 
1109 get_pages:
1110 	get_pages_start = xe_svm_stats_ktime_get();
1111 
1112 	range_debug(range, "GET PAGES");
1113 	err = xe_svm_range_get_pages(vm, range, &ctx);
1114 	/* Corner where CPU mappings have changed */
1115 	if (err == -EOPNOTSUPP || err == -EFAULT || err == -EPERM) {
1116 		ctx.timeslice_ms <<= 1;	/* Double timeslice if we have to retry */
1117 		if (migrate_try_count > 0 || !ctx.devmem_only) {
1118 			drm_dbg(&vm->xe->drm,
1119 				"Get pages failed, falling back to retrying, asid=%u, gpusvm=%p, errno=%pe\n",
1120 				vm->usm.asid, &vm->svm.gpusvm, ERR_PTR(err));
1121 			range_debug(range, "PAGE FAULT - RETRY PAGES");
1122 			goto retry;
1123 		} else {
1124 			drm_err(&vm->xe->drm,
1125 				"Get pages failed, retry count exceeded, asid=%u, gpusvm=%p, errno=%pe\n",
1126 				vm->usm.asid, &vm->svm.gpusvm, ERR_PTR(err));
1127 		}
1128 	}
1129 	if (err) {
1130 		range_debug(range, "PAGE FAULT - FAIL PAGE COLLECT");
1131 		goto out;
1132 	}
1133 
1134 	xe_svm_range_get_pages_us_stats_incr(gt, range, get_pages_start);
1135 	range_debug(range, "PAGE FAULT - BIND");
1136 
1137 	bind_start = xe_svm_stats_ktime_get();
1138 	xe_validation_guard(&vctx, &vm->xe->val, &exec, (struct xe_val_flags) {}, err) {
1139 		err = xe_vm_drm_exec_lock(vm, &exec);
1140 		drm_exec_retry_on_contention(&exec);
1141 
1142 		xe_vm_set_validation_exec(vm, &exec);
1143 		fence = xe_vm_range_rebind(vm, vma, range, BIT(tile->id));
1144 		xe_vm_set_validation_exec(vm, NULL);
1145 		if (IS_ERR(fence)) {
1146 			drm_exec_retry_on_contention(&exec);
1147 			err = PTR_ERR(fence);
1148 			xe_validation_retry_on_oom(&vctx, &err);
1149 			xe_svm_range_bind_us_stats_incr(gt, range, bind_start);
1150 			break;
1151 		}
1152 	}
1153 	if (err)
1154 		goto err_out;
1155 
1156 	dma_fence_wait(fence, false);
1157 	dma_fence_put(fence);
1158 	xe_svm_range_bind_us_stats_incr(gt, range, bind_start);
1159 
1160 out:
1161 	xe_svm_range_fault_us_stats_incr(gt, range, start);
1162 	return 0;
1163 
1164 err_out:
1165 	if (err == -EAGAIN) {
1166 		ctx.timeslice_ms <<= 1;	/* Double timeslice if we have to retry */
1167 		range_debug(range, "PAGE FAULT - RETRY BIND");
1168 		goto retry;
1169 	}
1170 
1171 	return err;
1172 }
1173 
1174 /**
1175  * xe_svm_handle_pagefault() - SVM handle page fault
1176  * @vm: The VM.
1177  * @vma: The CPU address mirror VMA.
1178  * @gt: The gt upon the fault occurred.
1179  * @fault_addr: The GPU fault address.
1180  * @atomic: The fault atomic access bit.
1181  *
1182  * Create GPU bindings for a SVM page fault. Optionally migrate to device
1183  * memory.
1184  *
1185  * Return: 0 on success, negative error code on error.
1186  */
1187 int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
1188 			    struct xe_gt *gt, u64 fault_addr,
1189 			    bool atomic)
1190 {
1191 	int need_vram, ret;
1192 retry:
1193 	need_vram = xe_vma_need_vram_for_atomic(vm->xe, vma, atomic);
1194 	if (need_vram < 0)
1195 		return need_vram;
1196 
1197 	ret =  __xe_svm_handle_pagefault(vm, vma, gt, fault_addr,
1198 					 need_vram ? true : false);
1199 	if (ret == -EAGAIN) {
1200 		/*
1201 		 * Retry once on -EAGAIN to re-lookup the VMA, as the original VMA
1202 		 * may have been split by xe_svm_range_set_default_attr.
1203 		 */
1204 		vma = xe_vm_find_vma_by_addr(vm, fault_addr);
1205 		if (!vma)
1206 			return -EINVAL;
1207 
1208 		goto retry;
1209 	}
1210 	return ret;
1211 }
1212 
1213 /**
1214  * xe_svm_has_mapping() - SVM has mappings
1215  * @vm: The VM.
1216  * @start: Start address.
1217  * @end: End address.
1218  *
1219  * Check if an address range has SVM mappings.
1220  *
1221  * Return: True if address range has a SVM mapping, False otherwise
1222  */
1223 bool xe_svm_has_mapping(struct xe_vm *vm, u64 start, u64 end)
1224 {
1225 	return drm_gpusvm_has_mapping(&vm->svm.gpusvm, start, end);
1226 }
1227 
1228 /**
1229  * xe_svm_unmap_address_range - UNMAP SVM mappings and ranges
1230  * @vm: The VM
1231  * @start: start addr
1232  * @end: end addr
1233  *
1234  * This function UNMAPS svm ranges if start or end address are inside them.
1235  */
1236 void xe_svm_unmap_address_range(struct xe_vm *vm, u64 start, u64 end)
1237 {
1238 	struct drm_gpusvm_notifier *notifier, *next;
1239 
1240 	lockdep_assert_held_write(&vm->lock);
1241 
1242 	drm_gpusvm_for_each_notifier_safe(notifier, next, &vm->svm.gpusvm, start, end) {
1243 		struct drm_gpusvm_range *range, *__next;
1244 
1245 		drm_gpusvm_for_each_range_safe(range, __next, notifier, start, end) {
1246 			if (start > drm_gpusvm_range_start(range) ||
1247 			    end < drm_gpusvm_range_end(range)) {
1248 				if (IS_DGFX(vm->xe) && xe_svm_range_in_vram(to_xe_range(range)))
1249 					drm_gpusvm_range_evict(&vm->svm.gpusvm, range);
1250 				drm_gpusvm_range_get(range);
1251 				__xe_svm_garbage_collector(vm, to_xe_range(range));
1252 				if (!list_empty(&to_xe_range(range)->garbage_collector_link)) {
1253 					spin_lock(&vm->svm.garbage_collector.lock);
1254 					list_del(&to_xe_range(range)->garbage_collector_link);
1255 					spin_unlock(&vm->svm.garbage_collector.lock);
1256 				}
1257 				drm_gpusvm_range_put(range);
1258 			}
1259 		}
1260 	}
1261 }
1262 
1263 /**
1264  * xe_svm_bo_evict() - SVM evict BO to system memory
1265  * @bo: BO to evict
1266  *
1267  * SVM evict BO to system memory. GPU SVM layer ensures all device pages
1268  * are evicted before returning.
1269  *
1270  * Return: 0 on success standard error code otherwise
1271  */
1272 int xe_svm_bo_evict(struct xe_bo *bo)
1273 {
1274 	return drm_pagemap_evict_to_ram(&bo->devmem_allocation);
1275 }
1276 
1277 /**
1278  * xe_svm_range_find_or_insert- Find or insert GPU SVM range
1279  * @vm: xe_vm pointer
1280  * @addr: address for which range needs to be found/inserted
1281  * @vma:  Pointer to struct xe_vma which mirrors CPU
1282  * @ctx: GPU SVM context
1283  *
1284  * This function finds or inserts a newly allocated a SVM range based on the
1285  * address.
1286  *
1287  * Return: Pointer to the SVM range on success, ERR_PTR() on failure.
1288  */
1289 struct xe_svm_range *xe_svm_range_find_or_insert(struct xe_vm *vm, u64 addr,
1290 						 struct xe_vma *vma, struct drm_gpusvm_ctx *ctx)
1291 {
1292 	struct drm_gpusvm_range *r;
1293 
1294 	r = drm_gpusvm_range_find_or_insert(&vm->svm.gpusvm, max(addr, xe_vma_start(vma)),
1295 					    xe_vma_start(vma), xe_vma_end(vma), ctx);
1296 	if (IS_ERR(r))
1297 		return ERR_CAST(r);
1298 
1299 	return to_xe_range(r);
1300 }
1301 
1302 /**
1303  * xe_svm_range_get_pages() - Get pages for a SVM range
1304  * @vm: Pointer to the struct xe_vm
1305  * @range: Pointer to the xe SVM range structure
1306  * @ctx: GPU SVM context
1307  *
1308  * This function gets pages for a SVM range and ensures they are mapped for
1309  * DMA access. In case of failure with -EOPNOTSUPP, it evicts the range.
1310  *
1311  * Return: 0 on success, negative error code on failure.
1312  */
1313 int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range,
1314 			   struct drm_gpusvm_ctx *ctx)
1315 {
1316 	int err = 0;
1317 
1318 	err = drm_gpusvm_range_get_pages(&vm->svm.gpusvm, &range->base, ctx);
1319 	if (err == -EOPNOTSUPP) {
1320 		range_debug(range, "PAGE FAULT - EVICT PAGES");
1321 		drm_gpusvm_range_evict(&vm->svm.gpusvm, &range->base);
1322 	}
1323 
1324 	return err;
1325 }
1326 
1327 /**
1328  * xe_svm_ranges_zap_ptes_in_range - clear ptes of svm ranges in input range
1329  * @vm: Pointer to the xe_vm structure
1330  * @start: Start of the input range
1331  * @end: End of the input range
1332  *
1333  * This function removes the page table entries (PTEs) associated
1334  * with the svm ranges within the given input start and end
1335  *
1336  * Return: tile_mask for which gt's need to be tlb invalidated.
1337  */
1338 u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end)
1339 {
1340 	struct drm_gpusvm_notifier *notifier;
1341 	struct xe_svm_range *range;
1342 	u64 adj_start, adj_end;
1343 	struct xe_tile *tile;
1344 	u8 tile_mask = 0;
1345 	u8 id;
1346 
1347 	lockdep_assert(lockdep_is_held_type(&vm->svm.gpusvm.notifier_lock, 1) &&
1348 		       lockdep_is_held_type(&vm->lock, 0));
1349 
1350 	drm_gpusvm_for_each_notifier(notifier, &vm->svm.gpusvm, start, end) {
1351 		struct drm_gpusvm_range *r = NULL;
1352 
1353 		adj_start = max(start, drm_gpusvm_notifier_start(notifier));
1354 		adj_end = min(end, drm_gpusvm_notifier_end(notifier));
1355 		drm_gpusvm_for_each_range(r, notifier, adj_start, adj_end) {
1356 			range = to_xe_range(r);
1357 			for_each_tile(tile, vm->xe, id) {
1358 				if (xe_pt_zap_ptes_range(tile, vm, range)) {
1359 					tile_mask |= BIT(id);
1360 					/*
1361 					 * WRITE_ONCE pairs with READ_ONCE in
1362 					 * xe_vm_has_valid_gpu_mapping().
1363 					 * Must not fail after setting
1364 					 * tile_invalidated and before
1365 					 * TLB invalidation.
1366 					 */
1367 					WRITE_ONCE(range->tile_invalidated,
1368 						   range->tile_invalidated | BIT(id));
1369 				}
1370 			}
1371 		}
1372 	}
1373 
1374 	return tile_mask;
1375 }
1376 
1377 #if IS_ENABLED(CONFIG_DRM_XE_PAGEMAP)
1378 
1379 static struct drm_pagemap *tile_local_pagemap(struct xe_tile *tile)
1380 {
1381 	return &tile->mem.vram->dpagemap;
1382 }
1383 
1384 /**
1385  * xe_vma_resolve_pagemap - Resolve the appropriate DRM pagemap for a VMA
1386  * @vma: Pointer to the xe_vma structure containing memory attributes
1387  * @tile: Pointer to the xe_tile structure used as fallback for VRAM mapping
1388  *
1389  * This function determines the correct DRM pagemap to use for a given VMA.
1390  * It first checks if a valid devmem_fd is provided in the VMA's preferred
1391  * location. If the devmem_fd is negative, it returns NULL, indicating no
1392  * pagemap is available and smem to be used as preferred location.
1393  * If the devmem_fd is equal to the default faulting
1394  * GT identifier, it returns the VRAM pagemap associated with the tile.
1395  *
1396  * Future support for multi-device configurations may use drm_pagemap_from_fd()
1397  * to resolve pagemaps from arbitrary file descriptors.
1398  *
1399  * Return: A pointer to the resolved drm_pagemap, or NULL if none is applicable.
1400  */
1401 struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *tile)
1402 {
1403 	s32 fd = (s32)vma->attr.preferred_loc.devmem_fd;
1404 
1405 	if (fd == DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM)
1406 		return NULL;
1407 
1408 	if (fd == DRM_XE_PREFERRED_LOC_DEFAULT_DEVICE)
1409 		return IS_DGFX(tile_to_xe(tile)) ? tile_local_pagemap(tile) : NULL;
1410 
1411 	/* TODO: Support multi-device with drm_pagemap_from_fd(fd) */
1412 	return NULL;
1413 }
1414 
1415 /**
1416  * xe_svm_alloc_vram()- Allocate device memory pages for range,
1417  * migrating existing data.
1418  * @tile: tile to allocate vram from
1419  * @range: SVM range
1420  * @ctx: DRM GPU SVM context
1421  *
1422  * Return: 0 on success, error code on failure.
1423  */
1424 int xe_svm_alloc_vram(struct xe_tile *tile, struct xe_svm_range *range,
1425 		      const struct drm_gpusvm_ctx *ctx)
1426 {
1427 	struct drm_pagemap *dpagemap;
1428 
1429 	xe_assert(tile_to_xe(tile), range->base.pages.flags.migrate_devmem);
1430 	range_debug(range, "ALLOCATE VRAM");
1431 
1432 	dpagemap = tile_local_pagemap(tile);
1433 	return drm_pagemap_populate_mm(dpagemap, xe_svm_range_start(range),
1434 				       xe_svm_range_end(range),
1435 				       range->base.gpusvm->mm,
1436 				       ctx->timeslice_ms);
1437 }
1438 
1439 static struct drm_pagemap_addr
1440 xe_drm_pagemap_device_map(struct drm_pagemap *dpagemap,
1441 			  struct device *dev,
1442 			  struct page *page,
1443 			  unsigned int order,
1444 			  enum dma_data_direction dir)
1445 {
1446 	struct device *pgmap_dev = dpagemap->dev;
1447 	enum drm_interconnect_protocol prot;
1448 	dma_addr_t addr;
1449 
1450 	if (pgmap_dev == dev) {
1451 		addr = xe_vram_region_page_to_dpa(page_to_vr(page), page);
1452 		prot = XE_INTERCONNECT_VRAM;
1453 	} else {
1454 		addr = DMA_MAPPING_ERROR;
1455 		prot = 0;
1456 	}
1457 
1458 	return drm_pagemap_addr_encode(addr, prot, order, dir);
1459 }
1460 
1461 static const struct drm_pagemap_ops xe_drm_pagemap_ops = {
1462 	.device_map = xe_drm_pagemap_device_map,
1463 	.populate_mm = xe_drm_pagemap_populate_mm,
1464 };
1465 
1466 /**
1467  * xe_devm_add: Remap and provide memmap backing for device memory
1468  * @tile: tile that the memory region belongs to
1469  * @vr: vram memory region to remap
1470  *
1471  * This remap device memory to host physical address space and create
1472  * struct page to back device memory
1473  *
1474  * Return: 0 on success standard error code otherwise
1475  */
1476 int xe_devm_add(struct xe_tile *tile, struct xe_vram_region *vr)
1477 {
1478 	struct xe_device *xe = tile_to_xe(tile);
1479 	struct device *dev = &to_pci_dev(xe->drm.dev)->dev;
1480 	struct resource *res;
1481 	void *addr;
1482 	int ret;
1483 
1484 	res = devm_request_free_mem_region(dev, &iomem_resource,
1485 					   vr->usable_size);
1486 	if (IS_ERR(res)) {
1487 		ret = PTR_ERR(res);
1488 		return ret;
1489 	}
1490 
1491 	vr->pagemap.type = MEMORY_DEVICE_PRIVATE;
1492 	vr->pagemap.range.start = res->start;
1493 	vr->pagemap.range.end = res->end;
1494 	vr->pagemap.nr_range = 1;
1495 	vr->pagemap.ops = drm_pagemap_pagemap_ops_get();
1496 	vr->pagemap.owner = xe_svm_devm_owner(xe);
1497 	addr = devm_memremap_pages(dev, &vr->pagemap);
1498 
1499 	vr->dpagemap.dev = dev;
1500 	vr->dpagemap.ops = &xe_drm_pagemap_ops;
1501 
1502 	if (IS_ERR(addr)) {
1503 		devm_release_mem_region(dev, res->start, resource_size(res));
1504 		ret = PTR_ERR(addr);
1505 		drm_err(&xe->drm, "Failed to remap tile %d memory, errno %pe\n",
1506 			tile->id, ERR_PTR(ret));
1507 		return ret;
1508 	}
1509 	vr->hpa_base = res->start;
1510 
1511 	drm_dbg(&xe->drm, "Added tile %d memory [%llx-%llx] to devm, remapped to %pr\n",
1512 		tile->id, vr->io_start, vr->io_start + vr->usable_size, res);
1513 	return 0;
1514 }
1515 #else
1516 int xe_svm_alloc_vram(struct xe_tile *tile,
1517 		      struct xe_svm_range *range,
1518 		      const struct drm_gpusvm_ctx *ctx)
1519 {
1520 	return -EOPNOTSUPP;
1521 }
1522 
1523 int xe_devm_add(struct xe_tile *tile, struct xe_vram_region *vr)
1524 {
1525 	return 0;
1526 }
1527 
1528 struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *tile)
1529 {
1530 	return NULL;
1531 }
1532 #endif
1533 
1534 /**
1535  * xe_svm_flush() - SVM flush
1536  * @vm: The VM.
1537  *
1538  * Flush all SVM actions.
1539  */
1540 void xe_svm_flush(struct xe_vm *vm)
1541 {
1542 	if (xe_vm_in_fault_mode(vm))
1543 		flush_work(&vm->svm.garbage_collector.work);
1544 }
1545