xref: /linux/drivers/gpu/drm/xe/xe_bo.h (revision 83d5acca1f4f6132038ea88c72c5844f62e42d44)
1 /* SPDX-License-Identifier: MIT */
2 /*
3  * Copyright © 2021 Intel Corporation
4  */
5 
6 #ifndef _XE_BO_H_
7 #define _XE_BO_H_
8 
9 #include <drm/drm_prime.h>
10 #include <drm/ttm/ttm_tt.h>
11 
12 #include <xen/xen.h>
13 
14 #include "xe_bo_types.h"
15 #include "xe_ggtt.h"
16 #include "xe_macros.h"
17 #include "xe_validation.h"
18 #include "xe_vm_types.h"
19 #include "xe_vm.h"
20 #include "xe_vram_types.h"
21 
22 #define XE_DEFAULT_GTT_SIZE_MB          3072ULL /* 3GB by default */
23 
24 #define XE_BO_FLAG_USER		BIT(0)
25 /* The bits below need to be contiguous, or things break */
26 #define XE_BO_FLAG_SYSTEM		BIT(1)
27 #define XE_BO_FLAG_VRAM0		BIT(2)
28 #define XE_BO_FLAG_VRAM1		BIT(3)
29 #define XE_BO_FLAG_VRAM_MASK		(XE_BO_FLAG_VRAM0 | XE_BO_FLAG_VRAM1)
30 /* -- */
31 #define XE_BO_FLAG_STOLEN		BIT(4)
32 #define XE_BO_FLAG_VRAM(vram)		(XE_BO_FLAG_VRAM0 << ((vram)->id))
33 #define XE_BO_FLAG_VRAM_IF_DGFX(tile)	(IS_DGFX(tile_to_xe(tile)) ? \
34 					 XE_BO_FLAG_VRAM((tile)->mem.vram) : \
35 					 XE_BO_FLAG_SYSTEM)
36 #define XE_BO_FLAG_GGTT			BIT(5)
37 #define XE_BO_FLAG_IGNORE_MIN_PAGE_SIZE BIT(6)
38 #define XE_BO_FLAG_PINNED		BIT(7)
39 #define XE_BO_FLAG_NO_RESV_EVICT	BIT(8)
40 #define XE_BO_FLAG_DEFER_BACKING	BIT(9)
41 #define XE_BO_FLAG_FORCE_WC		BIT(10)
42 #define XE_BO_FLAG_FIXED_PLACEMENT	BIT(11)
43 #define XE_BO_FLAG_PAGETABLE		BIT(12)
44 #define XE_BO_FLAG_NEEDS_CPU_ACCESS	BIT(13)
45 #define XE_BO_FLAG_NEEDS_UC		BIT(14)
46 #define XE_BO_FLAG_NEEDS_64K		BIT(15)
47 #define XE_BO_FLAG_NEEDS_2M		BIT(16)
48 #define XE_BO_FLAG_GGTT_INVALIDATE	BIT(17)
49 #define XE_BO_FLAG_PINNED_NORESTORE	BIT(18)
50 #define XE_BO_FLAG_PINNED_LATE_RESTORE	BIT(19)
51 #define XE_BO_FLAG_GGTT0		BIT(20)
52 #define XE_BO_FLAG_GGTT1		BIT(21)
53 #define XE_BO_FLAG_GGTT2		BIT(22)
54 #define XE_BO_FLAG_GGTT3		BIT(23)
55 #define XE_BO_FLAG_CPU_ADDR_MIRROR	BIT(24)
56 #define XE_BO_FLAG_FORCE_USER_VRAM	BIT(25)
57 #define XE_BO_FLAG_NO_COMPRESSION	BIT(26)
58 #define XE_BO_FLAG_NEEDS_1G		BIT(27)
59 
60 /* this one is trigger internally only */
61 #define XE_BO_FLAG_INTERNAL_TEST	BIT(30)
62 #define XE_BO_FLAG_INTERNAL_64K		BIT(31)
63 
64 #define XE_BO_FLAG_GGTT_ALL		(XE_BO_FLAG_GGTT0 | \
65 					 XE_BO_FLAG_GGTT1 | \
66 					 XE_BO_FLAG_GGTT2 | \
67 					 XE_BO_FLAG_GGTT3)
68 
69 #define XE_BO_FLAG_GGTTx(tile) \
70 	(XE_BO_FLAG_GGTT0 << (tile)->id)
71 
72 #define XE_PTE_SHIFT			12
73 #define XE_PAGE_SIZE			(1 << XE_PTE_SHIFT)
74 #define XE_PTE_MASK			(XE_PAGE_SIZE - 1)
75 #define XE_PDE_SHIFT			(XE_PTE_SHIFT - 3)
76 #define XE_PDES				(1 << XE_PDE_SHIFT)
77 #define XE_PDE_MASK			(XE_PDES - 1)
78 
79 #define XE_64K_PTE_SHIFT		16
80 #define XE_64K_PAGE_SIZE		(1 << XE_64K_PTE_SHIFT)
81 #define XE_64K_PTE_MASK			(XE_64K_PAGE_SIZE - 1)
82 #define XE_64K_PDE_MASK			(XE_PDE_MASK >> 4)
83 
84 #define XE_PL_SYSTEM		TTM_PL_SYSTEM
85 #define XE_PL_TT		TTM_PL_TT
86 #define XE_PL_VRAM0		TTM_PL_VRAM
87 #define XE_PL_VRAM1		(XE_PL_VRAM0 + 1)
88 #define XE_PL_STOLEN		(TTM_NUM_MEM_TYPES - 1)
89 
90 #define XE_BO_PROPS_INVALID	(-1)
91 
92 #define XE_PCI_BARRIER_MMAP_OFFSET	(0x50 << XE_PTE_SHIFT)
93 
94 /**
95  * enum xe_madv_purgeable_state - Buffer object purgeable state enumeration
96  *
97  * This enum defines the possible purgeable states for a buffer object,
98  * allowing userspace to provide memory usage hints to the kernel for
99  * better memory management under pressure.
100  *
101  * @XE_MADV_PURGEABLE_WILLNEED: The buffer object is needed and should not be purged.
102  * This is the default state.
103  * @XE_MADV_PURGEABLE_DONTNEED: The buffer object is not currently needed and can be
104  * purged by the kernel under memory pressure.
105  * @XE_MADV_PURGEABLE_PURGED: The buffer object has been purged by the kernel.
106  *
107  * Accessing a purged buffer will result in an error. Per i915 semantics,
108  * once purged, a BO remains permanently invalid and must be destroyed and recreated.
109  */
110 enum xe_madv_purgeable_state {
111 	XE_MADV_PURGEABLE_WILLNEED,
112 	XE_MADV_PURGEABLE_DONTNEED,
113 	XE_MADV_PURGEABLE_PURGED,
114 };
115 
116 struct sg_table;
117 
118 struct xe_bo *xe_bo_alloc(void);
119 void xe_bo_free(struct xe_bo *bo);
120 
121 struct xe_bo *xe_bo_init_locked(struct xe_device *xe, struct xe_bo *bo,
122 				struct xe_tile *tile, struct dma_resv *resv,
123 				struct ttm_lru_bulk_move *bulk, size_t size,
124 				u16 cpu_caching, enum ttm_bo_type type,
125 				u32 flags, struct dma_buf *dma_buf,
126 				struct drm_exec *exec);
127 struct xe_bo *xe_bo_create_locked(struct xe_device *xe, struct xe_tile *tile,
128 				  struct xe_vm *vm, size_t size,
129 				  enum ttm_bo_type type, u32 flags,
130 				  struct drm_exec *exec);
131 struct xe_bo *xe_bo_create_user(struct xe_device *xe, struct xe_vm *vm, size_t size,
132 				u16 cpu_caching, u32 flags, struct drm_exec *exec);
133 struct xe_bo *xe_bo_create_pin_map(struct xe_device *xe, struct xe_tile *tile,
134 				   struct xe_vm *vm, size_t size,
135 				   enum ttm_bo_type type, u32 flags,
136 				   struct drm_exec *exec);
137 struct xe_bo *xe_bo_create_pin_map_novm(struct xe_device *xe, struct xe_tile *tile,
138 					size_t size, enum ttm_bo_type type, u32 flags,
139 					bool intr);
140 struct xe_bo *xe_bo_create_pin_range_novm(struct xe_device *xe, struct xe_tile *tile,
141 					  size_t size, u64 start, u64 end,
142 					  enum ttm_bo_type type, u32 flags);
143 struct xe_bo *
144 xe_bo_create_pin_map_at_novm(struct xe_device *xe, struct xe_tile *tile,
145 			     size_t size, u64 offset, enum ttm_bo_type type,
146 			     u32 flags, u64 alignment, bool intr);
147 struct xe_bo *xe_managed_bo_create_pin_map(struct xe_device *xe, struct xe_tile *tile,
148 					   size_t size, u32 flags);
149 void xe_managed_bo_unpin_map_no_vm(struct xe_bo *bo);
150 struct xe_bo *xe_managed_bo_create_from_data(struct xe_device *xe, struct xe_tile *tile,
151 					     const void *data, size_t size, u32 flags);
152 int xe_managed_bo_reinit_in_vram(struct xe_device *xe, struct xe_tile *tile, struct xe_bo **src);
153 
154 int xe_bo_placement_for_flags(struct xe_device *xe, struct xe_bo *bo,
155 			      u32 bo_flags, enum ttm_bo_type type);
156 
157 static inline struct xe_bo *ttm_to_xe_bo(const struct ttm_buffer_object *bo)
158 {
159 	return container_of(bo, struct xe_bo, ttm);
160 }
161 
162 static inline struct xe_bo *gem_to_xe_bo(const struct drm_gem_object *obj)
163 {
164 	return container_of(obj, struct xe_bo, ttm.base);
165 }
166 
167 #define xe_bo_device(bo) ttm_to_xe_device((bo)->ttm.bdev)
168 
169 static inline struct xe_bo *xe_bo_get(struct xe_bo *bo)
170 {
171 	if (bo)
172 		drm_gem_object_get(&bo->ttm.base);
173 
174 	return bo;
175 }
176 
177 void xe_bo_put(struct xe_bo *bo);
178 
179 /*
180  * xe_bo_get_unless_zero() - Conditionally obtain a GEM object refcount on an
181  * xe bo
182  * @bo: The bo for which we want to obtain a refcount.
183  *
184  * There is a short window between where the bo's GEM object refcount reaches
185  * zero and where we put the final ttm_bo reference. Code in the eviction- and
186  * shrinking path should therefore attempt to grab a gem object reference before
187  * trying to use members outside of the base class ttm object. This function is
188  * intended for that purpose. On successful return, this function must be paired
189  * with an xe_bo_put().
190  *
191  * Return: @bo on success, NULL on failure.
192  */
193 static inline __must_check struct xe_bo *xe_bo_get_unless_zero(struct xe_bo *bo)
194 {
195 	if (!bo || !kref_get_unless_zero(&bo->ttm.base.refcount))
196 		return NULL;
197 
198 	return bo;
199 }
200 
201 static inline void __xe_bo_unset_bulk_move(struct xe_bo *bo)
202 {
203 	if (bo)
204 		ttm_bo_set_bulk_move(&bo->ttm, NULL);
205 }
206 
207 static inline void xe_bo_assert_held(struct xe_bo *bo)
208 {
209 	if (bo)
210 		dma_resv_assert_held((bo)->ttm.base.resv);
211 }
212 
213 int xe_bo_lock(struct xe_bo *bo, bool intr);
214 
215 void xe_bo_unlock(struct xe_bo *bo);
216 
217 static inline void xe_bo_unlock_vm_held(struct xe_bo *bo)
218 {
219 	if (bo) {
220 		XE_WARN_ON(bo->vm && bo->ttm.base.resv != xe_vm_resv(bo->vm));
221 		if (bo->vm)
222 			xe_vm_assert_held(bo->vm);
223 		else
224 			dma_resv_unlock(bo->ttm.base.resv);
225 	}
226 }
227 
228 int xe_bo_pin_external(struct xe_bo *bo, bool in_place, struct drm_exec *exec);
229 int xe_bo_pin(struct xe_bo *bo, struct drm_exec *exec);
230 void xe_bo_unpin_external(struct xe_bo *bo);
231 void xe_bo_unpin(struct xe_bo *bo);
232 void xe_bo_pin_account(struct xe_bo *bo);
233 void xe_bo_unpin_account(struct xe_bo *bo);
234 int xe_bo_validate(struct xe_bo *bo, struct xe_vm *vm, bool allow_res_evict,
235 		   struct drm_exec *exec);
236 
237 static inline bool xe_bo_is_pinned(struct xe_bo *bo)
238 {
239 	return bo->ttm.pin_count;
240 }
241 
242 static inline bool xe_bo_is_protected(const struct xe_bo *bo)
243 {
244 	return bo->pxp_key_instance;
245 }
246 
247 /**
248  * xe_bo_is_purged() - Check if buffer object has been purged
249  * @bo: The buffer object to check
250  *
251  * Checks if the buffer object's backing store has been discarded by the
252  * kernel due to memory pressure after being marked as purgeable (DONTNEED).
253  * Once purged, the BO cannot be restored and any attempt to use it will fail.
254  *
255  * Context: Caller must hold the BO's dma-resv lock
256  * Return: true if the BO has been purged, false otherwise
257  */
258 static inline bool xe_bo_is_purged(struct xe_bo *bo)
259 {
260 	xe_bo_assert_held(bo);
261 	return bo->purgeable.state == XE_MADV_PURGEABLE_PURGED;
262 }
263 
264 /**
265  * xe_bo_madv_is_dontneed() - Check if BO is marked as DONTNEED
266  * @bo: The buffer object to check
267  *
268  * Checks if userspace has marked this BO as DONTNEED (i.e., its contents
269  * are not currently needed and can be discarded under memory pressure).
270  * This is used internally to decide whether a BO is eligible for purging.
271  *
272  * Context: Caller must hold the BO's dma-resv lock
273  * Return: true if the BO is marked DONTNEED, false otherwise
274  */
275 static inline bool xe_bo_madv_is_dontneed(struct xe_bo *bo)
276 {
277 	xe_bo_assert_held(bo);
278 	return bo->purgeable.state == XE_MADV_PURGEABLE_DONTNEED;
279 }
280 
281 void xe_bo_set_purgeable_state(struct xe_bo *bo, enum xe_madv_purgeable_state new_state);
282 
283 /**
284  * xe_bo_willneed_get_locked() - Acquire a WILLNEED holder on a BO
285  * @bo: Buffer object
286  *
287  * Increments willneed_count and, on a 0->1 transition, promotes the BO
288  * from DONTNEED to WILLNEED. PURGED is terminal and is never modified.
289  *
290  * Caller must hold the BO's dma-resv lock.
291  */
292 static inline void xe_bo_willneed_get_locked(struct xe_bo *bo)
293 {
294 	xe_bo_assert_held(bo);
295 
296 	/* Imported BOs are owned externally; do not track purgeability. */
297 	if (drm_gem_is_imported(&bo->ttm.base))
298 		return;
299 
300 	if (bo->purgeable.willneed_count++ == 0 && xe_bo_madv_is_dontneed(bo))
301 		xe_bo_set_purgeable_state(bo, XE_MADV_PURGEABLE_WILLNEED);
302 }
303 
304 /**
305  * xe_bo_willneed_put_locked() - Release a WILLNEED holder on a BO
306  * @bo: Buffer object
307  *
308  * Decrements willneed_count and, on a 1->0 transition, marks the BO
309  * DONTNEED only if it still has VMAs (implying all active VMAs are
310  * DONTNEED). If the last VMA is being removed, preserve the current BO
311  * state to match the previous VMA-walk semantics.
312  *
313  * PURGED is terminal and the BO state is never modified.
314  *
315  * Caller must hold the BO's dma-resv lock.
316  */
317 static inline void xe_bo_willneed_put_locked(struct xe_bo *bo)
318 {
319 	xe_bo_assert_held(bo);
320 
321 	if (drm_gem_is_imported(&bo->ttm.base))
322 		return;
323 
324 	xe_assert(xe_bo_device(bo), bo->purgeable.willneed_count > 0);
325 	if (--bo->purgeable.willneed_count == 0 && bo->purgeable.vma_count > 0 &&
326 	    !xe_bo_is_purged(bo))
327 		xe_bo_set_purgeable_state(bo, XE_MADV_PURGEABLE_DONTNEED);
328 }
329 
330 /**
331  * xe_bo_vma_count_inc_locked() - Account a new VMA on a BO
332  * @bo: Buffer object
333  *
334  * Increments vma_count.
335  *
336  * Caller must hold the BO's dma-resv lock.
337  */
338 static inline void xe_bo_vma_count_inc_locked(struct xe_bo *bo)
339 {
340 	xe_bo_assert_held(bo);
341 
342 	if (drm_gem_is_imported(&bo->ttm.base))
343 		return;
344 
345 	bo->purgeable.vma_count++;
346 }
347 
348 /**
349  * xe_bo_vma_count_dec_locked() - Account a VMA removal on a BO
350  * @bo: Buffer object
351  *
352  * Decrements vma_count.
353  *
354  * Caller must hold the BO's dma-resv lock.
355  */
356 static inline void xe_bo_vma_count_dec_locked(struct xe_bo *bo)
357 {
358 	xe_bo_assert_held(bo);
359 
360 	if (drm_gem_is_imported(&bo->ttm.base))
361 		return;
362 
363 	xe_assert(xe_bo_device(bo), bo->purgeable.vma_count > 0);
364 	bo->purgeable.vma_count--;
365 }
366 
367 static inline void xe_bo_unpin_map_no_vm(struct xe_bo *bo)
368 {
369 	if (likely(bo)) {
370 		xe_bo_lock(bo, false);
371 		xe_bo_unpin(bo);
372 		xe_bo_unlock(bo);
373 
374 		xe_bo_put(bo);
375 	}
376 }
377 
378 bool xe_bo_is_xe_bo(struct ttm_buffer_object *bo);
379 dma_addr_t __xe_bo_addr(struct xe_bo *bo, u64 offset, size_t page_size);
380 dma_addr_t xe_bo_addr(struct xe_bo *bo, u64 offset, size_t page_size);
381 
382 static inline dma_addr_t
383 xe_bo_main_addr(struct xe_bo *bo, size_t page_size)
384 {
385 	return xe_bo_addr(bo, 0, page_size);
386 }
387 
388 /**
389  * xe_bo_size() - Xe BO size
390  * @bo: The bo object.
391  *
392  * Simple helper to return Xe BO's size.
393  *
394  * Return: Xe BO's size
395  */
396 static inline size_t xe_bo_size(struct xe_bo *bo)
397 {
398 	return bo->ttm.base.size;
399 }
400 
401 static inline u32
402 __xe_bo_ggtt_addr(struct xe_bo *bo, u8 tile_id)
403 {
404 	struct xe_ggtt_node *ggtt_node = bo->ggtt_node[tile_id];
405 	u64 offset;
406 
407 	if (XE_WARN_ON(!ggtt_node))
408 		return 0;
409 
410 	offset = xe_ggtt_node_addr(ggtt_node);
411 	XE_WARN_ON(offset + xe_bo_size(bo) > (1ull << 32));
412 	return offset;
413 }
414 
415 static inline u32
416 xe_bo_ggtt_addr(struct xe_bo *bo)
417 {
418 	xe_assert(xe_bo_device(bo), bo->tile);
419 
420 	return __xe_bo_ggtt_addr(bo, bo->tile->id);
421 }
422 
423 int xe_bo_vmap(struct xe_bo *bo);
424 void xe_bo_vunmap(struct xe_bo *bo);
425 int xe_bo_read(struct xe_bo *bo, u64 offset, void *dst, int size);
426 
427 bool mem_type_is_vram(u32 mem_type);
428 bool xe_bo_is_vram(struct xe_bo *bo);
429 bool xe_bo_is_visible_vram(struct xe_bo *bo);
430 bool xe_bo_is_stolen(struct xe_bo *bo);
431 bool xe_bo_is_stolen_devmem(struct xe_bo *bo);
432 bool xe_bo_is_vm_bound(struct xe_bo *bo);
433 bool xe_bo_has_single_placement(struct xe_bo *bo);
434 uint64_t vram_region_gpu_offset(struct ttm_resource *res);
435 
436 bool xe_bo_can_migrate(struct xe_bo *bo, u32 mem_type);
437 
438 int xe_bo_migrate(struct xe_bo *bo, u32 mem_type, struct ttm_operation_ctx *ctc,
439 		  struct drm_exec *exec);
440 int xe_bo_evict(struct xe_bo *bo, struct drm_exec *exec);
441 
442 int xe_bo_evict_pinned(struct xe_bo *bo);
443 int xe_bo_notifier_prepare_pinned(struct xe_bo *bo);
444 int xe_bo_notifier_unprepare_pinned(struct xe_bo *bo);
445 int xe_bo_restore_pinned(struct xe_bo *bo);
446 
447 int xe_bo_dma_unmap_pinned(struct xe_bo *bo);
448 
449 extern const struct ttm_device_funcs xe_ttm_funcs;
450 extern const char *const xe_mem_type_to_name[];
451 
452 int xe_gem_create_ioctl(struct drm_device *dev, void *data,
453 			struct drm_file *file);
454 int xe_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
455 			     struct drm_file *file);
456 void xe_bo_runtime_pm_release_mmap_offset(struct xe_bo *bo);
457 
458 int xe_bo_dumb_create(struct drm_file *file_priv,
459 		      struct drm_device *dev,
460 		      struct drm_mode_create_dumb *args);
461 
462 bool xe_bo_needs_ccs_pages(struct xe_bo *bo);
463 
464 int xe_bo_decompress(struct xe_bo *bo);
465 
466 static inline size_t xe_bo_ccs_pages_start(struct xe_bo *bo)
467 {
468 	return PAGE_ALIGN(xe_bo_size(bo));
469 }
470 
471 /**
472  * xe_bo_has_valid_ccs_bb - Check if CCS's BBs were setup for the BO.
473  * @bo: the &xe_bo to check
474  *
475  * The CCS's BBs should only be setup by the driver VF, but it is safe
476  * to call this function also by non-VF driver.
477  *
478  * Return: true iff the CCS's BBs are setup, false otherwise.
479  */
480 static inline bool xe_bo_has_valid_ccs_bb(struct xe_bo *bo)
481 {
482 	return bo->bb_ccs[XE_SRIOV_VF_CCS_READ_CTX] &&
483 	       bo->bb_ccs[XE_SRIOV_VF_CCS_WRITE_CTX];
484 }
485 
486 static inline bool xe_bo_has_pages(struct xe_bo *bo)
487 {
488 	if ((bo->ttm.ttm && ttm_tt_is_populated(bo->ttm.ttm)) ||
489 	    xe_bo_is_vram(bo))
490 		return true;
491 
492 	return false;
493 }
494 
495 void __xe_bo_release_dummy(struct kref *kref);
496 
497 /**
498  * xe_bo_put_deferred() - Put a buffer object with delayed final freeing
499  * @bo: The bo to put.
500  * @deferred: List to which to add the buffer object if we cannot put, or
501  * NULL if the function is to put unconditionally.
502  *
503  * Since the final freeing of an object includes both sleeping and (!)
504  * memory allocation in the dma_resv individualization, it's not ok
505  * to put an object from atomic context nor from within a held lock
506  * tainted by reclaim. In such situations we want to defer the final
507  * freeing until we've exited the restricting context, or in the worst
508  * case to a workqueue.
509  * This function either puts the object if possible without the refcount
510  * reaching zero, or adds it to the @deferred list if that was not possible.
511  * The caller needs to follow up with a call to xe_bo_put_commit() to actually
512  * put the bo iff this function returns true. It's safe to always
513  * follow up with a call to xe_bo_put_commit().
514  * TODO: It's TTM that is the villain here. Perhaps TTM should add an
515  * interface like this.
516  *
517  * Return: true if @bo was the first object put on the @freed list,
518  * false otherwise.
519  */
520 static inline bool
521 xe_bo_put_deferred(struct xe_bo *bo, struct llist_head *deferred)
522 {
523 	if (!deferred) {
524 		xe_bo_put(bo);
525 		return false;
526 	}
527 
528 	if (!kref_put(&bo->ttm.base.refcount, __xe_bo_release_dummy))
529 		return false;
530 
531 	return llist_add(&bo->freed, deferred);
532 }
533 
534 void xe_bo_put_commit(struct llist_head *deferred);
535 
536 /**
537  * xe_bo_put_async() - Put BO async
538  * @bo: The bo to put.
539  *
540  * Put BO async, the final put is deferred to a worker to exit an IRQ context.
541  */
542 static inline void
543 xe_bo_put_async(struct xe_bo *bo)
544 {
545 	struct xe_bo_dev *bo_device = &xe_bo_device(bo)->bo_device;
546 
547 	if (xe_bo_put_deferred(bo, &bo_device->async_list))
548 		schedule_work(&bo_device->async_free);
549 }
550 
551 void xe_bo_dev_init(struct xe_bo_dev *bo_device);
552 
553 void xe_bo_dev_fini(struct xe_bo_dev *bo_device);
554 
555 struct sg_table *xe_bo_sg(struct xe_bo *bo);
556 
557 /**
558  * xe_bo_sg_is_contiguous() - Check if a BO's DMA address space is contiguous.
559  * @bo: the BO to check (must have a valid sg table, i.e. !xe_bo_is_vram())
560  * @len: required contiguous length in bytes
561  *
562  * Returns true if the first @len bytes of the BO are mapped to a contiguous
563  * DMA address range.
564  */
565 static inline bool xe_bo_sg_is_contiguous(struct xe_bo *bo, size_t len)
566 {
567 	return drm_prime_get_contiguous_size(xe_bo_sg(bo)) >= len;
568 }
569 
570 /*
571  * xe_sg_segment_size() - Provides upper limit for sg segment size.
572  * @dev: device pointer
573  *
574  * Returns the maximum segment size for the 'struct scatterlist'
575  * elements.
576  */
577 static inline unsigned int xe_sg_segment_size(struct device *dev)
578 {
579 	struct scatterlist __maybe_unused sg;
580 	size_t max = BIT_ULL(sizeof(sg.length) * 8) - 1;
581 
582 	/*
583 	 * For Xen PV guests pages aren't contiguous in DMA (machine) address
584 	 * space.  The DMA API takes care of that both in dma_alloc_* (by
585 	 * calling into the hypervisor to make the pages contiguous) and in
586 	 * dma_map_* (by bounce buffering).  But xe (like i915, see commit
587 	 * 78a07fe777c4) ignores the coherency aspects of the DMA API and thus
588 	 * can't cope with bounce buffering actually happening, so add a hack
589 	 * here to force small allocations and mappings when running in PV
590 	 * mode on Xen.
591 	 *
592 	 * Note this will still break if bounce buffering is required for other
593 	 * reasons, like confidential computing hypervisors or PCIe root ports
594 	 * with addressing limitations.
595 	 */
596 	if (xen_pv_domain())
597 		return PAGE_SIZE;
598 
599 	max = min_t(size_t, max, dma_max_mapping_size(dev));
600 
601 	/*
602 	 * The iommu_dma_map_sg() function ensures iova allocation doesn't
603 	 * cross dma segment boundary. It does so by padding some sg elements.
604 	 * This can cause overflow, ending up with sg->length being set to 0.
605 	 * Avoid this by ensuring maximum segment size is half of 'max'
606 	 * rounded down to PAGE_SIZE.
607 	 */
608 	return round_down(max / 2, PAGE_SIZE);
609 }
610 
611 /**
612  * struct xe_bo_shrink_flags - flags governing the shrink behaviour.
613  * @purge: Only purging allowed. Don't shrink if bo not purgeable.
614  * @writeback: Attempt to immediately move content to swap.
615  */
616 struct xe_bo_shrink_flags {
617 	u32 purge : 1;
618 	u32 writeback : 1;
619 };
620 
621 long xe_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo,
622 		  const struct xe_bo_shrink_flags flags,
623 		  unsigned long *scanned);
624 
625 /**
626  * xe_bo_is_mem_type - Whether the bo currently resides in the given
627  * TTM memory type
628  * @bo: The bo to check.
629  * @mem_type: The TTM memory type.
630  *
631  * Return: true iff the bo resides in @mem_type, false otherwise.
632  */
633 static inline bool xe_bo_is_mem_type(struct xe_bo *bo, u32 mem_type)
634 {
635 	xe_bo_assert_held(bo);
636 	return bo->ttm.resource->mem_type == mem_type;
637 }
638 #endif
639