cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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i915_gem_object.c (23095B)


      1/*
      2 * Copyright © 2017 Intel Corporation
      3 *
      4 * Permission is hereby granted, free of charge, to any person obtaining a
      5 * copy of this software and associated documentation files (the "Software"),
      6 * to deal in the Software without restriction, including without limitation
      7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8 * and/or sell copies of the Software, and to permit persons to whom the
      9 * Software is furnished to do so, subject to the following conditions:
     10 *
     11 * The above copyright notice and this permission notice (including the next
     12 * paragraph) shall be included in all copies or substantial portions of the
     13 * 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 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     21 * IN THE SOFTWARE.
     22 *
     23 */
     24
     25#include <linux/highmem.h>
     26#include <linux/sched/mm.h>
     27
     28#include <drm/drm_cache.h>
     29
     30#include "display/intel_frontbuffer.h"
     31#include "pxp/intel_pxp.h"
     32
     33#include "i915_drv.h"
     34#include "i915_file_private.h"
     35#include "i915_gem_clflush.h"
     36#include "i915_gem_context.h"
     37#include "i915_gem_dmabuf.h"
     38#include "i915_gem_mman.h"
     39#include "i915_gem_object.h"
     40#include "i915_gem_ttm.h"
     41#include "i915_memcpy.h"
     42#include "i915_trace.h"
     43
     44static struct kmem_cache *slab_objects;
     45
     46static const struct drm_gem_object_funcs i915_gem_object_funcs;
     47
     48struct drm_i915_gem_object *i915_gem_object_alloc(void)
     49{
     50	struct drm_i915_gem_object *obj;
     51
     52	obj = kmem_cache_zalloc(slab_objects, GFP_KERNEL);
     53	if (!obj)
     54		return NULL;
     55	obj->base.funcs = &i915_gem_object_funcs;
     56
     57	return obj;
     58}
     59
     60void i915_gem_object_free(struct drm_i915_gem_object *obj)
     61{
     62	return kmem_cache_free(slab_objects, obj);
     63}
     64
     65void i915_gem_object_init(struct drm_i915_gem_object *obj,
     66			  const struct drm_i915_gem_object_ops *ops,
     67			  struct lock_class_key *key, unsigned flags)
     68{
     69	/*
     70	 * A gem object is embedded both in a struct ttm_buffer_object :/ and
     71	 * in a drm_i915_gem_object. Make sure they are aliased.
     72	 */
     73	BUILD_BUG_ON(offsetof(typeof(*obj), base) !=
     74		     offsetof(typeof(*obj), __do_not_access.base));
     75
     76	spin_lock_init(&obj->vma.lock);
     77	INIT_LIST_HEAD(&obj->vma.list);
     78
     79	INIT_LIST_HEAD(&obj->mm.link);
     80
     81	INIT_LIST_HEAD(&obj->lut_list);
     82	spin_lock_init(&obj->lut_lock);
     83
     84	spin_lock_init(&obj->mmo.lock);
     85	obj->mmo.offsets = RB_ROOT;
     86
     87	init_rcu_head(&obj->rcu);
     88
     89	obj->ops = ops;
     90	GEM_BUG_ON(flags & ~I915_BO_ALLOC_FLAGS);
     91	obj->flags = flags;
     92
     93	obj->mm.madv = I915_MADV_WILLNEED;
     94	INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);
     95	mutex_init(&obj->mm.get_page.lock);
     96	INIT_RADIX_TREE(&obj->mm.get_dma_page.radix, GFP_KERNEL | __GFP_NOWARN);
     97	mutex_init(&obj->mm.get_dma_page.lock);
     98}
     99
    100/**
    101 * __i915_gem_object_fini - Clean up a GEM object initialization
    102 * @obj: The gem object to cleanup
    103 *
    104 * This function cleans up gem object fields that are set up by
    105 * drm_gem_private_object_init() and i915_gem_object_init().
    106 * It's primarily intended as a helper for backends that need to
    107 * clean up the gem object in separate steps.
    108 */
    109void __i915_gem_object_fini(struct drm_i915_gem_object *obj)
    110{
    111	mutex_destroy(&obj->mm.get_page.lock);
    112	mutex_destroy(&obj->mm.get_dma_page.lock);
    113	dma_resv_fini(&obj->base._resv);
    114}
    115
    116/**
    117 * i915_gem_object_set_cache_coherency - Mark up the object's coherency levels
    118 * for a given cache_level
    119 * @obj: #drm_i915_gem_object
    120 * @cache_level: cache level
    121 */
    122void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
    123					 unsigned int cache_level)
    124{
    125	struct drm_i915_private *i915 = to_i915(obj->base.dev);
    126
    127	obj->cache_level = cache_level;
    128
    129	if (cache_level != I915_CACHE_NONE)
    130		obj->cache_coherent = (I915_BO_CACHE_COHERENT_FOR_READ |
    131				       I915_BO_CACHE_COHERENT_FOR_WRITE);
    132	else if (HAS_LLC(i915))
    133		obj->cache_coherent = I915_BO_CACHE_COHERENT_FOR_READ;
    134	else
    135		obj->cache_coherent = 0;
    136
    137	obj->cache_dirty =
    138		!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE) &&
    139		!IS_DGFX(i915);
    140}
    141
    142bool i915_gem_object_can_bypass_llc(struct drm_i915_gem_object *obj)
    143{
    144	struct drm_i915_private *i915 = to_i915(obj->base.dev);
    145
    146	/*
    147	 * This is purely from a security perspective, so we simply don't care
    148	 * about non-userspace objects being able to bypass the LLC.
    149	 */
    150	if (!(obj->flags & I915_BO_ALLOC_USER))
    151		return false;
    152
    153	/*
    154	 * EHL and JSL add the 'Bypass LLC' MOCS entry, which should make it
    155	 * possible for userspace to bypass the GTT caching bits set by the
    156	 * kernel, as per the given object cache_level. This is troublesome
    157	 * since the heavy flush we apply when first gathering the pages is
    158	 * skipped if the kernel thinks the object is coherent with the GPU. As
    159	 * a result it might be possible to bypass the cache and read the
    160	 * contents of the page directly, which could be stale data. If it's
    161	 * just a case of userspace shooting themselves in the foot then so be
    162	 * it, but since i915 takes the stance of always zeroing memory before
    163	 * handing it to userspace, we need to prevent this.
    164	 */
    165	return IS_JSL_EHL(i915);
    166}
    167
    168static void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
    169{
    170	struct drm_i915_gem_object *obj = to_intel_bo(gem);
    171	struct drm_i915_file_private *fpriv = file->driver_priv;
    172	struct i915_lut_handle bookmark = {};
    173	struct i915_mmap_offset *mmo, *mn;
    174	struct i915_lut_handle *lut, *ln;
    175	LIST_HEAD(close);
    176
    177	spin_lock(&obj->lut_lock);
    178	list_for_each_entry_safe(lut, ln, &obj->lut_list, obj_link) {
    179		struct i915_gem_context *ctx = lut->ctx;
    180
    181		if (ctx && ctx->file_priv == fpriv) {
    182			i915_gem_context_get(ctx);
    183			list_move(&lut->obj_link, &close);
    184		}
    185
    186		/* Break long locks, and carefully continue on from this spot */
    187		if (&ln->obj_link != &obj->lut_list) {
    188			list_add_tail(&bookmark.obj_link, &ln->obj_link);
    189			if (cond_resched_lock(&obj->lut_lock))
    190				list_safe_reset_next(&bookmark, ln, obj_link);
    191			__list_del_entry(&bookmark.obj_link);
    192		}
    193	}
    194	spin_unlock(&obj->lut_lock);
    195
    196	spin_lock(&obj->mmo.lock);
    197	rbtree_postorder_for_each_entry_safe(mmo, mn, &obj->mmo.offsets, offset)
    198		drm_vma_node_revoke(&mmo->vma_node, file);
    199	spin_unlock(&obj->mmo.lock);
    200
    201	list_for_each_entry_safe(lut, ln, &close, obj_link) {
    202		struct i915_gem_context *ctx = lut->ctx;
    203		struct i915_vma *vma;
    204
    205		/*
    206		 * We allow the process to have multiple handles to the same
    207		 * vma, in the same fd namespace, by virtue of flink/open.
    208		 */
    209
    210		mutex_lock(&ctx->lut_mutex);
    211		vma = radix_tree_delete(&ctx->handles_vma, lut->handle);
    212		if (vma) {
    213			GEM_BUG_ON(vma->obj != obj);
    214			GEM_BUG_ON(!atomic_read(&vma->open_count));
    215			i915_vma_close(vma);
    216		}
    217		mutex_unlock(&ctx->lut_mutex);
    218
    219		i915_gem_context_put(lut->ctx);
    220		i915_lut_handle_free(lut);
    221		i915_gem_object_put(obj);
    222	}
    223}
    224
    225void __i915_gem_free_object_rcu(struct rcu_head *head)
    226{
    227	struct drm_i915_gem_object *obj =
    228		container_of(head, typeof(*obj), rcu);
    229	struct drm_i915_private *i915 = to_i915(obj->base.dev);
    230
    231	i915_gem_object_free(obj);
    232
    233	GEM_BUG_ON(!atomic_read(&i915->mm.free_count));
    234	atomic_dec(&i915->mm.free_count);
    235}
    236
    237static void __i915_gem_object_free_mmaps(struct drm_i915_gem_object *obj)
    238{
    239	/* Skip serialisation and waking the device if known to be not used. */
    240
    241	if (obj->userfault_count)
    242		i915_gem_object_release_mmap_gtt(obj);
    243
    244	if (!RB_EMPTY_ROOT(&obj->mmo.offsets)) {
    245		struct i915_mmap_offset *mmo, *mn;
    246
    247		i915_gem_object_release_mmap_offset(obj);
    248
    249		rbtree_postorder_for_each_entry_safe(mmo, mn,
    250						     &obj->mmo.offsets,
    251						     offset) {
    252			drm_vma_offset_remove(obj->base.dev->vma_offset_manager,
    253					      &mmo->vma_node);
    254			kfree(mmo);
    255		}
    256		obj->mmo.offsets = RB_ROOT;
    257	}
    258}
    259
    260/**
    261 * __i915_gem_object_pages_fini - Clean up pages use of a gem object
    262 * @obj: The gem object to clean up
    263 *
    264 * This function cleans up usage of the object mm.pages member. It
    265 * is intended for backends that need to clean up a gem object in
    266 * separate steps and needs to be called when the object is idle before
    267 * the object's backing memory is freed.
    268 */
    269void __i915_gem_object_pages_fini(struct drm_i915_gem_object *obj)
    270{
    271	assert_object_held(obj);
    272
    273	if (!list_empty(&obj->vma.list)) {
    274		struct i915_vma *vma;
    275
    276		spin_lock(&obj->vma.lock);
    277		while ((vma = list_first_entry_or_null(&obj->vma.list,
    278						       struct i915_vma,
    279						       obj_link))) {
    280			GEM_BUG_ON(vma->obj != obj);
    281			spin_unlock(&obj->vma.lock);
    282
    283			i915_vma_destroy(vma);
    284
    285			spin_lock(&obj->vma.lock);
    286		}
    287		spin_unlock(&obj->vma.lock);
    288	}
    289
    290	__i915_gem_object_free_mmaps(obj);
    291
    292	atomic_set(&obj->mm.pages_pin_count, 0);
    293	__i915_gem_object_put_pages(obj);
    294	GEM_BUG_ON(i915_gem_object_has_pages(obj));
    295}
    296
    297void __i915_gem_free_object(struct drm_i915_gem_object *obj)
    298{
    299	trace_i915_gem_object_destroy(obj);
    300
    301	GEM_BUG_ON(!list_empty(&obj->lut_list));
    302
    303	bitmap_free(obj->bit_17);
    304
    305	if (obj->base.import_attach)
    306		drm_prime_gem_destroy(&obj->base, NULL);
    307
    308	drm_gem_free_mmap_offset(&obj->base);
    309
    310	if (obj->ops->release)
    311		obj->ops->release(obj);
    312
    313	if (obj->mm.n_placements > 1)
    314		kfree(obj->mm.placements);
    315
    316	if (obj->shares_resv_from)
    317		i915_vm_resv_put(obj->shares_resv_from);
    318
    319	__i915_gem_object_fini(obj);
    320}
    321
    322static void __i915_gem_free_objects(struct drm_i915_private *i915,
    323				    struct llist_node *freed)
    324{
    325	struct drm_i915_gem_object *obj, *on;
    326
    327	llist_for_each_entry_safe(obj, on, freed, freed) {
    328		might_sleep();
    329		if (obj->ops->delayed_free) {
    330			obj->ops->delayed_free(obj);
    331			continue;
    332		}
    333
    334		if (!i915_gem_object_trylock(obj, NULL)) {
    335			/* busy, toss it back to the pile */
    336			if (llist_add(&obj->freed, &i915->mm.free_list))
    337				queue_delayed_work(i915->wq, &i915->mm.free_work, msecs_to_jiffies(10));
    338			continue;
    339		}
    340
    341		__i915_gem_object_pages_fini(obj);
    342		i915_gem_object_unlock(obj);
    343		__i915_gem_free_object(obj);
    344
    345		/* But keep the pointer alive for RCU-protected lookups */
    346		call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
    347		cond_resched();
    348	}
    349}
    350
    351void i915_gem_flush_free_objects(struct drm_i915_private *i915)
    352{
    353	struct llist_node *freed = llist_del_all(&i915->mm.free_list);
    354
    355	if (unlikely(freed))
    356		__i915_gem_free_objects(i915, freed);
    357}
    358
    359static void __i915_gem_free_work(struct work_struct *work)
    360{
    361	struct drm_i915_private *i915 =
    362		container_of(work, struct drm_i915_private, mm.free_work.work);
    363
    364	i915_gem_flush_free_objects(i915);
    365}
    366
    367static void i915_gem_free_object(struct drm_gem_object *gem_obj)
    368{
    369	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
    370	struct drm_i915_private *i915 = to_i915(obj->base.dev);
    371
    372	GEM_BUG_ON(i915_gem_object_is_framebuffer(obj));
    373
    374	/*
    375	 * Before we free the object, make sure any pure RCU-only
    376	 * read-side critical sections are complete, e.g.
    377	 * i915_gem_busy_ioctl(). For the corresponding synchronized
    378	 * lookup see i915_gem_object_lookup_rcu().
    379	 */
    380	atomic_inc(&i915->mm.free_count);
    381
    382	/*
    383	 * Since we require blocking on struct_mutex to unbind the freed
    384	 * object from the GPU before releasing resources back to the
    385	 * system, we can not do that directly from the RCU callback (which may
    386	 * be a softirq context), but must instead then defer that work onto a
    387	 * kthread. We use the RCU callback rather than move the freed object
    388	 * directly onto the work queue so that we can mix between using the
    389	 * worker and performing frees directly from subsequent allocations for
    390	 * crude but effective memory throttling.
    391	 */
    392
    393	if (llist_add(&obj->freed, &i915->mm.free_list))
    394		queue_delayed_work(i915->wq, &i915->mm.free_work, 0);
    395}
    396
    397void __i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj,
    398					 enum fb_op_origin origin)
    399{
    400	struct intel_frontbuffer *front;
    401
    402	front = __intel_frontbuffer_get(obj);
    403	if (front) {
    404		intel_frontbuffer_flush(front, origin);
    405		intel_frontbuffer_put(front);
    406	}
    407}
    408
    409void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
    410					      enum fb_op_origin origin)
    411{
    412	struct intel_frontbuffer *front;
    413
    414	front = __intel_frontbuffer_get(obj);
    415	if (front) {
    416		intel_frontbuffer_invalidate(front, origin);
    417		intel_frontbuffer_put(front);
    418	}
    419}
    420
    421static void
    422i915_gem_object_read_from_page_kmap(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
    423{
    424	void *src_map;
    425	void *src_ptr;
    426
    427	src_map = kmap_atomic(i915_gem_object_get_page(obj, offset >> PAGE_SHIFT));
    428
    429	src_ptr = src_map + offset_in_page(offset);
    430	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ))
    431		drm_clflush_virt_range(src_ptr, size);
    432	memcpy(dst, src_ptr, size);
    433
    434	kunmap_atomic(src_map);
    435}
    436
    437static void
    438i915_gem_object_read_from_page_iomap(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
    439{
    440	void __iomem *src_map;
    441	void __iomem *src_ptr;
    442	dma_addr_t dma = i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT);
    443
    444	src_map = io_mapping_map_wc(&obj->mm.region->iomap,
    445				    dma - obj->mm.region->region.start,
    446				    PAGE_SIZE);
    447
    448	src_ptr = src_map + offset_in_page(offset);
    449	if (!i915_memcpy_from_wc(dst, (void __force *)src_ptr, size))
    450		memcpy_fromio(dst, src_ptr, size);
    451
    452	io_mapping_unmap(src_map);
    453}
    454
    455/**
    456 * i915_gem_object_read_from_page - read data from the page of a GEM object
    457 * @obj: GEM object to read from
    458 * @offset: offset within the object
    459 * @dst: buffer to store the read data
    460 * @size: size to read
    461 *
    462 * Reads data from @obj at the specified offset. The requested region to read
    463 * from can't cross a page boundary. The caller must ensure that @obj pages
    464 * are pinned and that @obj is synced wrt. any related writes.
    465 *
    466 * Return: %0 on success or -ENODEV if the type of @obj's backing store is
    467 * unsupported.
    468 */
    469int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
    470{
    471	GEM_BUG_ON(offset >= obj->base.size);
    472	GEM_BUG_ON(offset_in_page(offset) > PAGE_SIZE - size);
    473	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
    474
    475	if (i915_gem_object_has_struct_page(obj))
    476		i915_gem_object_read_from_page_kmap(obj, offset, dst, size);
    477	else if (i915_gem_object_has_iomem(obj))
    478		i915_gem_object_read_from_page_iomap(obj, offset, dst, size);
    479	else
    480		return -ENODEV;
    481
    482	return 0;
    483}
    484
    485/**
    486 * i915_gem_object_evictable - Whether object is likely evictable after unbind.
    487 * @obj: The object to check
    488 *
    489 * This function checks whether the object is likely unvictable after unbind.
    490 * If the object is not locked when checking, the result is only advisory.
    491 * If the object is locked when checking, and the function returns true,
    492 * then an eviction should indeed be possible. But since unlocked vma
    493 * unpinning and unbinding is currently possible, the object can actually
    494 * become evictable even if this function returns false.
    495 *
    496 * Return: true if the object may be evictable. False otherwise.
    497 */
    498bool i915_gem_object_evictable(struct drm_i915_gem_object *obj)
    499{
    500	struct i915_vma *vma;
    501	int pin_count = atomic_read(&obj->mm.pages_pin_count);
    502
    503	if (!pin_count)
    504		return true;
    505
    506	spin_lock(&obj->vma.lock);
    507	list_for_each_entry(vma, &obj->vma.list, obj_link) {
    508		if (i915_vma_is_pinned(vma)) {
    509			spin_unlock(&obj->vma.lock);
    510			return false;
    511		}
    512		if (atomic_read(&vma->pages_count))
    513			pin_count--;
    514	}
    515	spin_unlock(&obj->vma.lock);
    516	GEM_WARN_ON(pin_count < 0);
    517
    518	return pin_count == 0;
    519}
    520
    521/**
    522 * i915_gem_object_migratable - Whether the object is migratable out of the
    523 * current region.
    524 * @obj: Pointer to the object.
    525 *
    526 * Return: Whether the object is allowed to be resident in other
    527 * regions than the current while pages are present.
    528 */
    529bool i915_gem_object_migratable(struct drm_i915_gem_object *obj)
    530{
    531	struct intel_memory_region *mr = READ_ONCE(obj->mm.region);
    532
    533	if (!mr)
    534		return false;
    535
    536	return obj->mm.n_placements > 1;
    537}
    538
    539/**
    540 * i915_gem_object_has_struct_page - Whether the object is page-backed
    541 * @obj: The object to query.
    542 *
    543 * This function should only be called while the object is locked or pinned,
    544 * otherwise the page backing may change under the caller.
    545 *
    546 * Return: True if page-backed, false otherwise.
    547 */
    548bool i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj)
    549{
    550#ifdef CONFIG_LOCKDEP
    551	if (IS_DGFX(to_i915(obj->base.dev)) &&
    552	    i915_gem_object_evictable((void __force *)obj))
    553		assert_object_held_shared(obj);
    554#endif
    555	return obj->mem_flags & I915_BO_FLAG_STRUCT_PAGE;
    556}
    557
    558/**
    559 * i915_gem_object_has_iomem - Whether the object is iomem-backed
    560 * @obj: The object to query.
    561 *
    562 * This function should only be called while the object is locked or pinned,
    563 * otherwise the iomem backing may change under the caller.
    564 *
    565 * Return: True if iomem-backed, false otherwise.
    566 */
    567bool i915_gem_object_has_iomem(const struct drm_i915_gem_object *obj)
    568{
    569#ifdef CONFIG_LOCKDEP
    570	if (IS_DGFX(to_i915(obj->base.dev)) &&
    571	    i915_gem_object_evictable((void __force *)obj))
    572		assert_object_held_shared(obj);
    573#endif
    574	return obj->mem_flags & I915_BO_FLAG_IOMEM;
    575}
    576
    577/**
    578 * i915_gem_object_can_migrate - Whether an object likely can be migrated
    579 *
    580 * @obj: The object to migrate
    581 * @id: The region intended to migrate to
    582 *
    583 * Check whether the object backend supports migration to the
    584 * given region. Note that pinning may affect the ability to migrate as
    585 * returned by this function.
    586 *
    587 * This function is primarily intended as a helper for checking the
    588 * possibility to migrate objects and might be slightly less permissive
    589 * than i915_gem_object_migrate() when it comes to objects with the
    590 * I915_BO_ALLOC_USER flag set.
    591 *
    592 * Return: true if migration is possible, false otherwise.
    593 */
    594bool i915_gem_object_can_migrate(struct drm_i915_gem_object *obj,
    595				 enum intel_region_id id)
    596{
    597	struct drm_i915_private *i915 = to_i915(obj->base.dev);
    598	unsigned int num_allowed = obj->mm.n_placements;
    599	struct intel_memory_region *mr;
    600	unsigned int i;
    601
    602	GEM_BUG_ON(id >= INTEL_REGION_UNKNOWN);
    603	GEM_BUG_ON(obj->mm.madv != I915_MADV_WILLNEED);
    604
    605	mr = i915->mm.regions[id];
    606	if (!mr)
    607		return false;
    608
    609	if (!IS_ALIGNED(obj->base.size, mr->min_page_size))
    610		return false;
    611
    612	if (obj->mm.region == mr)
    613		return true;
    614
    615	if (!i915_gem_object_evictable(obj))
    616		return false;
    617
    618	if (!obj->ops->migrate)
    619		return false;
    620
    621	if (!(obj->flags & I915_BO_ALLOC_USER))
    622		return true;
    623
    624	if (num_allowed == 0)
    625		return false;
    626
    627	for (i = 0; i < num_allowed; ++i) {
    628		if (mr == obj->mm.placements[i])
    629			return true;
    630	}
    631
    632	return false;
    633}
    634
    635/**
    636 * i915_gem_object_migrate - Migrate an object to the desired region id
    637 * @obj: The object to migrate.
    638 * @ww: An optional struct i915_gem_ww_ctx. If NULL, the backend may
    639 * not be successful in evicting other objects to make room for this object.
    640 * @id: The region id to migrate to.
    641 *
    642 * Attempt to migrate the object to the desired memory region. The
    643 * object backend must support migration and the object may not be
    644 * pinned, (explicitly pinned pages or pinned vmas). The object must
    645 * be locked.
    646 * On successful completion, the object will have pages pointing to
    647 * memory in the new region, but an async migration task may not have
    648 * completed yet, and to accomplish that, i915_gem_object_wait_migration()
    649 * must be called.
    650 *
    651 * Note: the @ww parameter is not used yet, but included to make sure
    652 * callers put some effort into obtaining a valid ww ctx if one is
    653 * available.
    654 *
    655 * Return: 0 on success. Negative error code on failure. In particular may
    656 * return -ENXIO on lack of region space, -EDEADLK for deadlock avoidance
    657 * if @ww is set, -EINTR or -ERESTARTSYS if signal pending, and
    658 * -EBUSY if the object is pinned.
    659 */
    660int i915_gem_object_migrate(struct drm_i915_gem_object *obj,
    661			    struct i915_gem_ww_ctx *ww,
    662			    enum intel_region_id id)
    663{
    664	struct drm_i915_private *i915 = to_i915(obj->base.dev);
    665	struct intel_memory_region *mr;
    666
    667	GEM_BUG_ON(id >= INTEL_REGION_UNKNOWN);
    668	GEM_BUG_ON(obj->mm.madv != I915_MADV_WILLNEED);
    669	assert_object_held(obj);
    670
    671	mr = i915->mm.regions[id];
    672	GEM_BUG_ON(!mr);
    673
    674	if (!i915_gem_object_can_migrate(obj, id))
    675		return -EINVAL;
    676
    677	if (!obj->ops->migrate) {
    678		if (GEM_WARN_ON(obj->mm.region != mr))
    679			return -EINVAL;
    680		return 0;
    681	}
    682
    683	return obj->ops->migrate(obj, mr);
    684}
    685
    686/**
    687 * i915_gem_object_placement_possible - Check whether the object can be
    688 * placed at certain memory type
    689 * @obj: Pointer to the object
    690 * @type: The memory type to check
    691 *
    692 * Return: True if the object can be placed in @type. False otherwise.
    693 */
    694bool i915_gem_object_placement_possible(struct drm_i915_gem_object *obj,
    695					enum intel_memory_type type)
    696{
    697	unsigned int i;
    698
    699	if (!obj->mm.n_placements) {
    700		switch (type) {
    701		case INTEL_MEMORY_LOCAL:
    702			return i915_gem_object_has_iomem(obj);
    703		case INTEL_MEMORY_SYSTEM:
    704			return i915_gem_object_has_pages(obj);
    705		default:
    706			/* Ignore stolen for now */
    707			GEM_BUG_ON(1);
    708			return false;
    709		}
    710	}
    711
    712	for (i = 0; i < obj->mm.n_placements; i++) {
    713		if (obj->mm.placements[i]->type == type)
    714			return true;
    715	}
    716
    717	return false;
    718}
    719
    720void i915_gem_init__objects(struct drm_i915_private *i915)
    721{
    722	INIT_DELAYED_WORK(&i915->mm.free_work, __i915_gem_free_work);
    723}
    724
    725void i915_objects_module_exit(void)
    726{
    727	kmem_cache_destroy(slab_objects);
    728}
    729
    730int __init i915_objects_module_init(void)
    731{
    732	slab_objects = KMEM_CACHE(drm_i915_gem_object, SLAB_HWCACHE_ALIGN);
    733	if (!slab_objects)
    734		return -ENOMEM;
    735
    736	return 0;
    737}
    738
    739static const struct drm_gem_object_funcs i915_gem_object_funcs = {
    740	.free = i915_gem_free_object,
    741	.close = i915_gem_close_object,
    742	.export = i915_gem_prime_export,
    743};
    744
    745/**
    746 * i915_gem_object_get_moving_fence - Get the object's moving fence if any
    747 * @obj: The object whose moving fence to get.
    748 * @fence: The resulting fence
    749 *
    750 * A non-signaled moving fence means that there is an async operation
    751 * pending on the object that needs to be waited on before setting up
    752 * any GPU- or CPU PTEs to the object's pages.
    753 *
    754 * Return: Negative error code or 0 for success.
    755 */
    756int i915_gem_object_get_moving_fence(struct drm_i915_gem_object *obj,
    757				     struct dma_fence **fence)
    758{
    759	return dma_resv_get_singleton(obj->base.resv, DMA_RESV_USAGE_KERNEL,
    760				      fence);
    761}
    762
    763/**
    764 * i915_gem_object_wait_moving_fence - Wait for the object's moving fence if any
    765 * @obj: The object whose moving fence to wait for.
    766 * @intr: Whether to wait interruptible.
    767 *
    768 * If the moving fence signaled without an error, it is detached from the
    769 * object and put.
    770 *
    771 * Return: 0 if successful, -ERESTARTSYS if the wait was interrupted,
    772 * negative error code if the async operation represented by the
    773 * moving fence failed.
    774 */
    775int i915_gem_object_wait_moving_fence(struct drm_i915_gem_object *obj,
    776				      bool intr)
    777{
    778	long ret;
    779
    780	assert_object_held(obj);
    781
    782	ret = dma_resv_wait_timeout(obj->base. resv, DMA_RESV_USAGE_KERNEL,
    783				    intr, MAX_SCHEDULE_TIMEOUT);
    784	if (!ret)
    785		ret = -ETIME;
    786
    787	return ret < 0 ? ret : 0;
    788}
    789
    790#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
    791#include "selftests/huge_gem_object.c"
    792#include "selftests/huge_pages.c"
    793#include "selftests/i915_gem_migrate.c"
    794#include "selftests/i915_gem_object.c"
    795#include "selftests/i915_gem_coherency.c"
    796#endif