// SPDX-License-Identifier: MIT
/*
* Copyright © 2021 Intel Corporation
*/
#include <linux/shmem_fs.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/ttm/ttm_tt.h>
#include <drm/drm_buddy.h>
#include "i915_drv.h"
#include "i915_ttm_buddy_manager.h"
#include "intel_memory_region.h"
#include "intel_region_ttm.h"
#include "gem/i915_gem_mman.h"
#include "gem/i915_gem_object.h"
#include "gem/i915_gem_region.h"
#include "gem/i915_gem_ttm.h"
#include "gem/i915_gem_ttm_move.h"
#include "gem/i915_gem_ttm_pm.h"
#include "gt/intel_gpu_commands.h"
#define I915_TTM_PRIO_PURGE 0
#define I915_TTM_PRIO_NO_PAGES 1
#define I915_TTM_PRIO_HAS_PAGES 2
#define I915_TTM_PRIO_NEEDS_CPU_ACCESS 3
/*
* Size of struct ttm_place vector in on-stack struct ttm_placement allocs
*/
#define I915_TTM_MAX_PLACEMENTS INTEL_REGION_UNKNOWN
/**
* struct i915_ttm_tt - TTM page vector with additional private information
* @ttm: The base TTM page vector.
* @dev: The struct device used for dma mapping and unmapping.
* @cached_rsgt: The cached scatter-gather table.
* @is_shmem: Set if using shmem.
* @filp: The shmem file, if using shmem backend.
*
* Note that DMA may be going on right up to the point where the page-
* vector is unpopulated in delayed destroy. Hence keep the
* scatter-gather table mapped and cached up to that point. This is
* different from the cached gem object io scatter-gather table which
* doesn't have an associated dma mapping.
*/
struct i915_ttm_tt {
struct ttm_tt ttm;
struct device *dev;
struct i915_refct_sgt cached_rsgt;
bool is_shmem;
struct file *filp;
};
static const struct ttm_place sys_placement_flags = {
.fpfn = 0,
.lpfn = 0,
.mem_type = I915_PL_SYSTEM,
.flags = 0,
};
static struct ttm_placement i915_sys_placement = {
.num_placement = 1,
.placement = &sys_placement_flags,
};
/**
* i915_ttm_sys_placement - Return the struct ttm_placement to be
* used for an object in system memory.
*
* Rather than making the struct extern, use this
* function.
*
* Return: A pointer to a static variable for sys placement.
*/
struct ttm_placement *i915_ttm_sys_placement(void)
{
return &i915_sys_placement;
}
static int i915_ttm_err_to_gem(int err)
{
/* Fastpath */
if (likely(!err))
return 0;
switch (err) {
case -EBUSY:
/*
* TTM likes to convert -EDEADLK to -EBUSY, and wants us to
* restart the operation, since we don't record the contending
* lock. We use -EAGAIN to restart.
*/
return -EAGAIN;
case -ENOSPC:
/*
* Memory type / region is full, and we can't evict.
* Except possibly system, that returns -ENOMEM;
*/
return -ENXIO;
default:
break;
}
return err;
}
static enum ttm_caching
i915_ttm_select_tt_caching(const struct drm_i915_gem_object *obj)
{
/*
* Objects only allowed in system get cached cpu-mappings, or when
* evicting lmem-only buffers to system for swapping. Other objects get
* WC mapping for now. Even if in system.
*/
if (obj->mm.n_placements <= 1)
return ttm_cached;
return ttm_write_combined;
}
static void
i915_ttm_place_from_region(const struct intel_memory_region *mr,
struct ttm_place *place,
resource_size_t offset,
resource_size_t size,
unsigned int flags)
{
memset(place, 0, sizeof(*place));
place->mem_type = intel_region_to_ttm_type(mr);
if (mr->type == INTEL_MEMORY_SYSTEM)
return;
if (flags & I915_BO_ALLOC_CONTIGUOUS)
place->flags |= TTM_PL_FLAG_CONTIGUOUS;
if (offset != I915_BO_INVALID_OFFSET) {
WARN_ON(overflows_type(offset >> PAGE_SHIFT, place->fpfn));
place->fpfn = offset >> PAGE_SHIFT;
WARN_ON(overflows_type(place->fpfn + (size >> PAGE_SHIFT), place->lpfn));
place->lpfn = place->fpfn + (size >> PAGE_SHIFT);
} else if (resource_size(&mr->io) && resource_size(&mr->io) < mr->total) {
if (flags & I915_BO_ALLOC_GPU_ONLY) {
place->flags |= TTM_PL_FLAG_TOPDOWN;
} else {
place->fpfn = 0;
WARN_ON(overflows_type(resource_size(&mr->io) >> PAGE_SHIFT, place->lpfn));
place->lpfn = resource_size(&mr->io) >> PAGE_SHIFT;
}
}
}
static void
i915_ttm_placement_from_obj(const struct drm_i915_gem_object *obj,
struct ttm_place *places,
struct ttm_placement *placement)
{
unsigned int num_allowed = obj->mm.n_placements;
unsigned int flags = obj->flags;
unsigned int i;
i915_ttm_place_from_region(num_allowed ? obj->mm.placements[0] :
obj->mm.region, &places[0], obj->bo_offset,
obj->base.size, flags);
/* Cache this on object? */
for (i = 0; i < num_allowed; ++i) {
i915_ttm_place_from_region(obj->mm.placements[i],
&places[i + 1], obj->bo_offset,
obj->base.size, flags);
places[i + 1].flags |= TTM_PL_FLAG_FALLBACK;
}
placement->num_placement = num_allowed + 1;
placement->placement = places;
}
static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev,
struct ttm_tt *ttm,
struct ttm_operation_ctx *ctx)
{
struct drm_i915_private *i915 = container_of(bdev, typeof(*i915), bdev);
struct intel_memory_region *mr = i915->mm.regions[INTEL_MEMORY_SYSTEM];
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
const unsigned int max_segment = i915_sg_segment_size(i915->drm.dev);
const size_t size = (size_t)ttm->num_pages << PAGE_SHIFT;
struct file *filp = i915_tt->filp;
struct sgt_iter sgt_iter;
struct sg_table *st;
struct page *page;
unsigned long i;
int err;
if (!filp) {
struct address_space *mapping;
gfp_t mask;
filp = shmem_file_setup("i915-shmem-tt", size, VM_NORESERVE);
if (IS_ERR(filp))
return PTR_ERR(filp);
mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
mapping = filp->f_mapping;
mapping_set_gfp_mask(mapping, mask);
GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM));
i915_tt->filp = filp;
}
st = &i915_tt->cached_rsgt.table;
err = shmem_sg_alloc_table(i915, st, size, mr, filp->f_mapping,
max_segment);
if (err)
return err;
err = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL,
DMA_ATTR_SKIP_CPU_SYNC);
if (err)
goto err_free_st;
i = 0;
for_each_sgt_page(page, sgt_iter, st)
ttm->pages[i++] = page;
if (ttm->page_flags & TTM_TT_FLAG_SWAPPED)
ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
return 0;
err_free_st:
shmem_sg_free_table(st, filp->f_mapping, false, false);
return err;
}
static void i915_ttm_tt_shmem_unpopulate(struct ttm_tt *ttm)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
bool backup = ttm->page_flags & TTM_TT_FLAG_SWAPPED;
struct sg_table *st = &i915_tt->cached_rsgt.table;
shmem_sg_free_table(st, file_inode(i915_tt->filp)->i_mapping,
backup, backup);
}
static void i915_ttm_tt_release(struct kref *ref)
{
struct i915_ttm_tt *i915_tt =
container_of(ref, typeof(*i915_tt), cached_rsgt.kref);
struct sg_table *st = &i915_tt->cached_rsgt.table;
GEM_WARN_ON(st->sgl);
kfree(i915_tt);
}
static const struct i915_refct_sgt_ops tt_rsgt_ops = {
.release = i915_ttm_tt_release
};
static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
uint32_t page_flags)
{
struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915),
bdev);
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
unsigned long ccs_pages = 0;
enum ttm_caching caching;
struct i915_ttm_tt *i915_tt;
int ret;
if (i915_ttm_is_ghost_object(bo))
return NULL;
i915_tt = kzalloc(sizeof(*i915_tt), GFP_KERNEL);
if (!i915_tt)
return NULL;
if (obj->flags & I915_BO_ALLOC_CPU_CLEAR && (!bo->resource ||
ttm_manager_type(bo->bdev, bo->resource->mem_type)->use_tt))
page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
caching = i915_ttm_select_tt_caching(obj);
if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached) {
page_flags |= TTM_TT_FLAG_EXTERNAL |
TTM_TT_FLAG_EXTERNAL_MAPPABLE;
i915_tt->is_shmem = true;
}
if (i915_gem_object_needs_ccs_pages(obj))
ccs_pages = DIV_ROUND_UP(DIV_ROUND_UP(bo->base.size,
NUM_BYTES_PER_CCS_BYTE),
PAGE_SIZE);
ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, ccs_pages);
if (ret)
goto err_free;
__i915_refct_sgt_init(&i915_tt->cached_rsgt, bo->base.size,
&tt_rsgt_ops);
i915_tt->dev = obj->base.dev->dev;
return &i915_tt->ttm;
err_free:
kfree(i915_tt);
return NULL;
}
static int i915_ttm_tt_populate(struct ttm_device *bdev,
struct ttm_tt *ttm,
struct ttm_operation_ctx *ctx)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
if (i915_tt->is_shmem)
return i915_ttm_tt_shmem_populate(bdev, ttm, ctx);
return ttm_pool_alloc(&bdev->pool, ttm, ctx);
}
static void i915_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
struct sg_table *st = &i915_tt->cached_rsgt.table;
if (st->sgl)
dma_unmap_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0);
if (i915_tt->is_shmem) {
i915_ttm_tt_shmem_unpopulate(ttm);
} else {
sg_free_table(st);
ttm_pool_free(&bdev->pool, ttm);
}
}
static void i915_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
if (i915_tt->filp)
fput(i915_tt->filp);
ttm_tt_fini(ttm);
i915_refct_sgt_put(&i915_tt->cached_rsgt);
}
static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
const struct ttm_place *place)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
if (i915_ttm_is_ghost_object(bo))
return false;
/*
* EXTERNAL objects should never be swapped out by TTM, instead we need
* to handle that ourselves. TTM will already skip such objects for us,
* but we would like to avoid grabbing locks for no good reason.
*/
if (bo->ttm && bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)
return false;
/* Will do for now. Our pinned objects are still on TTM's LRU lists */
if (!i915_gem_object_evictable(obj))
return false;
return ttm_bo_eviction_valuable(bo, place);
}
static void i915_ttm_evict_flags(struct ttm_buffer_object *bo,
struct ttm_placement *placement)
{
*placement = i915_sys_placement;
}
/**
* i915_ttm_free_cached_io_rsgt - Free object cached LMEM information
* @obj: The GEM object
* This function frees any LMEM-related information that is cached on
* the object. For example the radix tree for fast page lookup and the
* cached refcounted sg-table
*/
void i915_ttm_free_cached_io_rsgt(struct drm_i915_gem_object *obj)
{
struct radix_tree_iter iter;
void __rcu **slot;
if (!obj->ttm.cached_io_rsgt)
return;
rcu_read_lock();
radix_tree_for_each_slot(slot, &obj->ttm.get_io_page.radix, &iter, 0)
radix_tree_delete(&obj->ttm.get_io_page.radix, iter.index);
rcu_read_unlock();
i915_refct_sgt_put(obj->ttm.cached_io_rsgt);
obj->ttm.cached_io_rsgt = NULL;
}
/**
* i915_ttm_purge - Clear an object of its memory
* @obj: The object
*
* This function is called to clear an object of it's memory when it is
* marked as not needed anymore.
*
* Return: 0 on success, negative error code on failure.
*/
int i915_ttm_purge(struct drm_i915_gem_object *obj)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
struct i915_ttm_tt *i915_tt =
container_of(bo->ttm, typeof(*i915_tt), ttm);
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = false,
};
struct ttm_placement place = {};
int ret;
if (obj->mm.madv == __I915_MADV_PURGED)
return 0;
ret = ttm_bo_validate(bo, &place, &ctx);
if (ret)
return ret;
if (bo->ttm && i915_tt->filp) {
/*
* The below fput(which eventually calls shmem_truncate) might
* be delayed by worker, so when directly called to purge the
* pages(like by the shrinker) we should try to be more
* aggressive and release the pages immediately.
*/
shmem_truncate_range(file_inode(i915_tt->filp),
0, (loff_t)-1);
fput(fetch_and_zero(&i915_tt->filp));
}
obj->write_domain = 0;
obj->read_domains = 0;
i915_ttm_adjust_gem_after_move(obj);
i915_ttm_free_cached_io_rsgt(obj);
obj->mm.madv = __I915_MADV_PURGED;
return 0;
}
static int i915_ttm_shrink(struct drm_i915_gem_object *obj, unsigned int flags)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
struct i915_ttm_tt *i915_tt =
container_of(bo->ttm, typeof(*i915_tt), ttm);
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = flags & I915_GEM_OBJECT_SHRINK_NO_GPU_WAIT,
};
struct ttm_placement place = {};
int ret;
if (!bo->ttm || i915_ttm_cpu_maps_iomem(bo->resource))
return 0;
GEM_BUG_ON(!i915_tt->is_shmem);
if (!i915_tt->filp)
return 0;
ret = ttm_bo_wait_ctx(bo, &ctx);
if (ret)
return ret;
switch (obj->mm.madv) {
case I915_MADV_DONTNEED:
return i915_ttm_purge(obj);
case __I915_MADV_PURGED:
return 0;
}
if (bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED)
return 0;
bo->ttm->page_flags |= TTM_TT_FLAG_SWAPPED;
ret = ttm_bo_validate(bo, &place, &ctx);
if (ret) {
bo->ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
return ret;
}
if (flags & I915_GEM_OBJECT_SHRINK_WRITEBACK)
__shmem_writeback(obj->base.size, i915_tt->filp->f_mapping);
return 0;
}
static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
/*
* This gets called twice by ttm, so long as we have a ttm resource or
* ttm_tt then we can still safely call this. Due to pipeline-gutting,
* we maybe have NULL bo->resource, but in that case we should always
* have a ttm alive (like if the pages are swapped out).
*/
if ((bo->resource || bo->ttm) && !i915_ttm_is_ghost_object(bo)) {
__i915_gem_object_pages_fini(obj);
i915_ttm_free_cached_io_rsgt(obj);
}
}
static struct i915_refct_sgt *i915_ttm_tt_get_st(struct ttm_tt *ttm)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
struct sg_table *st;
int ret;
if (i915_tt->cached_rsgt.table.sgl)
return i915_refct_sgt_get(&i915_tt->cached_rsgt);
st = &i915_tt->cached_rsgt.table;
ret = sg_alloc_table_from_pages_segment(st,
ttm->pages, ttm->num_pages,
0, (unsigned long)ttm->num_pages << PAGE_SHIFT,
i915_sg_segment_size(i915_tt->dev), GFP_KERNEL);
if (ret) {
st->sgl = NULL;
return ERR_PTR(ret);
}
ret = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0);
if (ret) {
sg_free_table(st);
return ERR_PTR(ret);
}
return i915_refct_sgt_get(&i915_tt->cached_rsgt);
}
/**
* i915_ttm_resource_get_st - Get a refcounted sg-table pointing to the
* resource memory
* @obj: The GEM object used for sg-table caching
* @res: The struct ttm_resource for which an sg-table is requested.
*
* This function returns a refcounted sg-table representing the memory
* pointed to by @res. If @res is the object's current resource it may also
* cache the sg_table on the object or attempt to access an already cached
* sg-table. The refcounted sg-table needs to be put when no-longer in use.
*
* Return: A valid pointer to a struct i915_refct_sgt or error pointer on
* failure.
*/
struct i915_refct_sgt *
i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
struct ttm_resource *res)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
u32 page_alignment;
if (!i915_ttm_gtt_binds_lmem(res))
return i915_ttm_tt_get_st(bo->ttm);
page_alignment = bo->page_alignment << PAGE_SHIFT;
if (!page_alignment)
page_alignment = obj->mm.region->min_page_size;
/*
* If CPU mapping differs, we need to add the ttm_tt pages to
* the resulting st. Might make sense for GGTT.
*/
GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(res));
if (bo->resource == res) {
if (!obj->ttm.cached_io_rsgt) {
struct i915_refct_sgt *rsgt;
rsgt = intel_region_ttm_resource_to_rsgt(obj->mm.region,
res,
page_alignment);
if (IS_ERR(rsgt))
return rsgt;
obj->ttm.cached_io_rsgt = rsgt;
}
return i915_refct_sgt_get(obj->ttm.cached_io_rsgt);
}
return intel_region_ttm_resource_to_rsgt(obj->mm.region, res,
page_alignment);
}
static int i915_ttm_truncate(struct drm_i915_gem_object *obj)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
long err;
WARN_ON_ONCE(obj->mm.madv == I915_MADV_WILLNEED);
err = dma_resv_wait_timeout(bo->base.resv, DMA_RESV_USAGE_BOOKKEEP,
true, 15 * HZ);
if (err < 0)
return err;
if (err == 0)
return -EBUSY;
err = i915_ttm_move_notify(bo);
if (err)
return err;
return i915_ttm_purge(obj);
}
static void i915_ttm_swap_notify(struct ttm_buffer_object *bo)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
int ret;
if (i915_ttm_is_ghost_object(bo))
return;
ret = i915_ttm_move_notify(bo);
GEM_WARN_ON(ret);
GEM_WARN_ON(obj->ttm.cached_io_rsgt);
if (!ret && obj->mm.madv != I915_MADV_WILLNEED)
i915_ttm_purge(obj);
}
/**
* i915_ttm_resource_mappable - Return true if the ttm resource is CPU
* accessible.
* @res: The TTM resource to check.
*
* This is interesting on small-BAR systems where we may encounter lmem objects
* that can't be accessed via the CPU.
*/
bool i915_ttm_resource_mappable(struct ttm_resource *res)
{
struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res);
if (!i915_ttm_cpu_maps_iomem(res))
return true;
return bman_res->used_visible_size == PFN_UP(bman_res->base.size);
}
static int i915_ttm_io_mem_reserve(struct ttm_device *bdev, struct ttm_resource *mem)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(mem->bo);
bool unknown_state;
if (i915_ttm_is_ghost_object(mem->bo))
return -EINVAL;
if (!kref_get_unless_zero(&obj->base.refcount))
return -EINVAL;
assert_object_held(obj);
unknown_state = i915_gem_object_has_unknown_state(obj);
i915_gem_object_put(obj);
if (unknown_state)
return -EINVAL;
if (!i915_ttm_cpu_maps_iomem(mem))
return 0;
if (!i915_ttm_resource_mappable(mem))
return -EINVAL;
mem->bus.caching = ttm_write_combined;
mem->bus.is_iomem = true;
return 0;
}
static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
unsigned long page_offset)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
struct scatterlist *sg;
unsigned long base;
unsigned int ofs;
GEM_BUG_ON(i915_ttm_is_ghost_object(bo));
GEM_WARN_ON(bo->ttm);
base = obj->mm.region->iomap.base - obj->mm.region->region.start;
sg = i915_gem_object_page_iter_get_sg(obj, &obj->ttm.get_io_page, page_offset, &ofs);
return ((base + sg_dma_address(sg)) >> PAGE_SHIFT) + ofs;
}
static int i915_ttm_access_memory(struct ttm_buffer_object *bo,
unsigned long offset, void *buf,
int len, int write)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
resource_size_t iomap = obj->mm.region->iomap.base -
obj->mm.region->region.start;
unsigned long page = offset >> PAGE_SHIFT;
unsigned long bytes_left = len;
/*
* TODO: For now just let it fail if the resource is non-mappable,
* otherwise we need to perform the memcpy from the gpu here, without
* interfering with the object (like moving the entire thing).
*/
if (!i915_ttm_resource_mappable(bo->resource))
return -EIO;
offset -= page << PAGE_SHIFT;
do {
unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
void __iomem *ptr;
dma_addr_t daddr;
daddr = i915_gem_object_get_dma_address(obj, page);
ptr = ioremap_wc(iomap + daddr + offset, bytes);
if (!ptr)
return -EIO;
if (write)
memcpy_toio(ptr, buf, bytes);
else
memcpy_fromio(buf, ptr, bytes);
iounmap(ptr);
page++;
buf += bytes;
bytes_left -= bytes;
offset = 0;
} while (bytes_left);
return len;
}
/*
* All callbacks need to take care not to downcast a struct ttm_buffer_object
* without checking its subclass, since it might be a TTM ghost object.
*/
static struct ttm_device_funcs i915_ttm_bo_driver = {
.ttm_tt_create = i915_ttm_tt_create,
.ttm_tt_populate = i915_ttm_tt_populate,
.ttm_tt_unpopulate = i915_ttm_tt_unpopulate,
.ttm_tt_destroy = i915_ttm_tt_destroy,
.eviction_valuable = i915_ttm_eviction_valuable,
.evict_flags = i915_ttm_evict_flags,
.move = i915_ttm_move,
.swap_notify = i915_ttm_swap_notify,
.delete_mem_notify = i915_ttm_delete_mem_notify,
.io_mem_reserve = i915_ttm_io_mem_reserve,
.io_mem_pfn = i915_ttm_io_mem_pfn,
.access_memory = i915_ttm_access_memory,
};
/**
* i915_ttm_driver - Return a pointer to the TTM device funcs
*
* Return: Pointer to statically allocated TTM device funcs.
*/
struct ttm_device_funcs *i915_ttm_driver(void)
{
return &i915_ttm_bo_driver;
}
static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
struct ttm_placement *placement)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = false,
};
struct ttm_placement initial_placement;
struct ttm_place initial_place;
int ret;
/* First try only the requested placement. No eviction. */
initial_placement.num_placement = 1;
memcpy(&initial_place, placement->placement, sizeof(struct ttm_place));
initial_place.flags |= TTM_PL_FLAG_DESIRED;
initial_placement.placement = &initial_place;
ret = ttm_bo_validate(bo, &initial_placement, &ctx);
if (ret) {
ret = i915_ttm_err_to_gem(ret);
/*
* Anything that wants to restart the operation gets to
* do that.
*/
if (ret == -EDEADLK || ret == -EINTR || ret == -ERESTARTSYS ||
ret == -EAGAIN)
return ret;
/*
* If the initial attempt fails, allow all accepted placements,
* evicting if necessary.
*/
ret = ttm_bo_validate(bo, placement, &ctx);
if (ret)
return i915_ttm_err_to_gem(ret);
}
if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) {
ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx);
if (ret)
return ret;
i915_ttm_adjust_domains_after_move(obj);
i915_ttm_adjust_gem_after_move(obj);
}
if (!i915_gem_object_has_pages(obj)) {
struct i915_refct_sgt *rsgt =
i915_ttm_resource_get_st(obj, bo->resource);
if (IS_ERR(rsgt))
return PTR_ERR(rsgt);
GEM_BUG_ON(obj->mm.rsgt);
obj->mm.rsgt = rsgt;
__i915_gem_object_set_pages(obj, &rsgt->table);
}
GEM_BUG_ON(bo->ttm && ((obj->base.size >> PAGE_SHIFT) < bo->ttm->num_pages));
i915_ttm_adjust_lru(obj);
return ret;
}
static int i915_ttm_get_pages(struct drm_i915_gem_object *obj)
{
struct ttm_place places[I915_TTM_MAX_PLACEMENTS + 1];
struct ttm_placement placement;
/* restricted by sg_alloc_table */
if (overflows_type(obj->base.size >> PAGE_SHIFT, unsigned int))
return -E2BIG;
GEM_BUG_ON(obj->mm.n_placements > I915_TTM_MAX_PLACEMENTS);
/* Move to the requested placement. */
i915_ttm_placement_from_obj(obj, places, &placement);
return __i915_ttm_get_pages(obj, &placement);
}
/**
* DOC: Migration vs eviction
*
* GEM migration may not be the same as TTM migration / eviction. If
* the TTM core decides to evict an object it may be evicted to a
* TTM memory type that is not in the object's allowable GEM regions, or
* in fact theoretically to a TTM memory type that doesn't correspond to
* a GEM memory region. In that case the object's GEM region is not
* updated, and the data is migrated back to the GEM region at
* get_pages time. TTM may however set up CPU ptes to the object even
* when it is evicted.
* Gem forced migration using the i915_ttm_migrate() op, is allowed even
* to regions that are not in the object's list of allowable placements.
*/
static int __i915_ttm_migrate(struct drm_i915_gem_object *obj,
struct intel_memory_region *mr,
unsigned int flags)
{
struct ttm_place requested;
struct ttm_placement placement;
int ret;
i915_ttm_place_from_region(mr, &requested, obj->bo_offset,
obj->base.size, flags);
placement.num_placement = 1;
placement.placement = &requested;
ret = __i915_ttm_get_pages(obj, &placement);
if (ret)
return ret;
/*
* Reinitialize the region bindings. This is primarily
* required for objects where the new region is not in
* its allowable placements.
*/
if (obj->mm.region != mr) {
i915_gem_object_release_memory_region(obj);
i915_gem_object_init_memory_region(obj, mr);
}
return 0;
}
static int i915_ttm_migrate(struct drm_i915_gem_object *obj,
struct intel_memory_region *mr,
unsigned int flags)
{
return __i915_ttm_migrate(obj, mr, flags);
}
static void i915_ttm_put_pages(struct drm_i915_gem_object *obj,
struct sg_table *st)
{
/*
* We're currently not called from a shrinker, so put_pages()
* typically means the object is about to destroyed, or called
* from move_notify(). So just avoid doing much for now.
* If the object is not destroyed next, The TTM eviction logic
* and shrinkers will move it out if needed.
*/
if (obj->mm.rsgt)
i915_refct_sgt_put(fetch_and_zero(&obj->mm.rsgt));
}
/**
* i915_ttm_adjust_lru - Adjust an object's position on relevant LRU lists.
* @obj: The object
*/
void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
struct i915_ttm_tt *i915_tt =
container_of(bo->ttm, typeof(*i915_tt), ttm);
bool shrinkable =
bo->ttm && i915_tt->filp && ttm_tt_is_populated(bo->ttm);
/*
* Don't manipulate the TTM LRUs while in TTM bo destruction.
* We're called through i915_ttm_delete_mem_notify().
*/
if (!kref_read(&bo->kref))
return;
/*
* We skip managing the shrinker LRU in set_pages() and just manage
* everything here. This does at least solve the issue with having
* temporary shmem mappings(like with evicted lmem) not being visible to
* the shrinker. Only our shmem objects are shrinkable, everything else
* we keep as unshrinkable.
*
* To make sure everything plays nice we keep an extra shrink pin in TTM
* if the underlying pages are not currently shrinkable. Once we release
* our pin, like when the pages are moved to shmem, the pages will then
* be added to the shrinker LRU, assuming the caller isn't also holding
* a pin.
*
* TODO: consider maybe also bumping the shrinker list here when we have
* already unpinned it, which should give us something more like an LRU.
*
* TODO: There is a small window of opportunity for this function to
* get called from eviction after we've dropped the last GEM refcount,
* but before the TTM deleted flag is set on the object. Avoid
* adjusting the shrinker list in such cases, since the object is
* not available to the shrinker anyway due to its zero refcount.
* To fix this properly we should move to a TTM shrinker LRU list for
* these objects.
*/
if (kref_get_unless_zero(&obj->base.refcount)) {
if (shrinkable != obj->mm.ttm_shrinkable) {
if (shrinkable) {
if (obj->mm.madv == I915_MADV_WILLNEED)
__i915_gem_object_make_shrinkable(obj);
else
__i915_gem_object_make_purgeable(obj);
} else {
i915_gem_object_make_unshrinkable(obj);
}
obj->mm.ttm_shrinkable = shrinkable;
}
i915_gem_object_put(obj);
}
/*
* Put on the correct LRU list depending on the MADV status
*/
spin_lock(&bo->bdev->lru_lock);
if (shrinkable) {
/* Try to keep shmem_tt from being considered for shrinking. */
bo->priority = TTM_MAX_BO_PRIORITY - 1;
} else if (obj->mm.madv != I915_MADV_WILLNEED) {
bo->priority = I915_TTM_PRIO_PURGE;
} else if (!i915_gem_object_has_pages(obj)) {
bo->priority = I915_TTM_PRIO_NO_PAGES;
} else {
struct ttm_resource_manager *man =
ttm_manager_type(bo->bdev, bo->resource->mem_type);
/*
* If we need to place an LMEM resource which doesn't need CPU
* access then we should try not to victimize mappable objects
* first, since we likely end up stealing more of the mappable
* portion. And likewise when we try to find space for a mappble
* object, we know not to ever victimize objects that don't
* occupy any mappable pages.
*/
if (i915_ttm_cpu_maps_iomem(bo->resource) &&
i915_ttm_buddy_man_visible_size(man) < man->size &&
!(obj->flags & I915_BO_ALLOC_GPU_ONLY))
bo->priority = I915_TTM_PRIO_NEEDS_CPU_ACCESS;
else
bo->priority = I915_TTM_PRIO_HAS_PAGES;
}
ttm_bo_move_to_lru_tail(bo);
spin_unlock(&bo->bdev->lru_lock);
}
/*
* TTM-backed gem object destruction requires some clarification.
* Basically we have two possibilities here. We can either rely on the
* i915 delayed destruction and put the TTM object when the object
* is idle. This would be detected by TTM which would bypass the
* TTM delayed destroy handling. The other approach is to put the TTM
* object early and rely on the TTM destroyed handling, and then free
* the leftover parts of the GEM object once TTM's destroyed list handling is
* complete. For now, we rely on the latter for two reasons:
* a) TTM can evict an object even when it's on the delayed destroy list,
* which in theory allows for complete eviction.
* b) There is work going on in TTM to allow freeing an object even when
* it's not idle, and using the TTM destroyed list handling could help us
* benefit from that.
*/
static void i915_ttm_delayed_free(struct drm_i915_gem_object *obj)
{
GEM_BUG_ON(!obj->ttm.created);
ttm_bo_put(i915_gem_to_ttm(obj));
}
static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
{
struct vm_area_struct *area = vmf->vma;
struct ttm_buffer_object *bo = area->vm_private_data;
struct drm_device *dev = bo->base.dev;
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
intel_wakeref_t wakeref = 0;
vm_fault_t ret;
int idx;
/* Sanity check that we allow writing into this object */
if (unlikely(i915_gem_object_is_readonly(obj) &&
area->vm_flags & VM_WRITE))
return VM_FAULT_SIGBUS;
ret = ttm_bo_vm_reserve(bo, vmf);
if (ret)
return ret;
if (obj->mm.madv != I915_MADV_WILLNEED) {
dma_resv_unlock(bo->base.resv);
return VM_FAULT_SIGBUS;
}
/*
* This must be swapped out with shmem ttm_tt (pipeline-gutting).
* Calling ttm_bo_validate() here with TTM_PL_SYSTEM should only go as
* far as far doing a ttm_bo_move_null(), which should skip all the
* other junk.
*/
if (!bo->resource) {
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = true, /* should be idle already */
};
int err;
GEM_BUG_ON(!bo->ttm || !(bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED));
err = ttm_bo_validate(bo, i915_ttm_sys_placement(), &ctx);
if (err) {
dma_resv_unlock(bo->base.resv);
return VM_FAULT_SIGBUS;
}
} else if (!i915_ttm_resource_mappable(bo->resource)) {
int err = -ENODEV;
int i;
for (i = 0; i < obj->mm.n_placements; i++) {
struct intel_memory_region *mr = obj->mm.placements[i];
unsigned int flags;
if (!resource_size(&mr->io) && mr->type != INTEL_MEMORY_SYSTEM)
continue;
flags = obj->flags;
flags &= ~I915_BO_ALLOC_GPU_ONLY;
err = __i915_ttm_migrate(obj, mr, flags);
if (!err)
break;
}
if (err) {
drm_dbg_ratelimited(dev,
"Unable to make resource CPU accessible(err = %pe)\n",
ERR_PTR(err));
dma_resv_unlock(bo->base.resv);
ret = VM_FAULT_SIGBUS;
goto out_rpm;
}
}
if (i915_ttm_cpu_maps_iomem(bo->resource))
wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm);
if (drm_dev_enter(dev, &idx)) {
ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
TTM_BO_VM_NUM_PREFAULT);
drm_dev_exit(idx);
} else {
ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
}
if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
goto out_rpm;
/*
* ttm_bo_vm_reserve() already has dma_resv_lock.
* userfault_count is protected by dma_resv lock and rpm wakeref.
*/
if (ret == VM_FAULT_NOPAGE && wakeref && !obj->userfault_count) {
obj->userfault_count = 1;
spin_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock);
list_add(&obj->userfault_link, &to_i915(obj->base.dev)->runtime_pm.lmem_userfault_list);
spin_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock);
GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(bo->resource));
}
if (wakeref && CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND != 0)
intel_wakeref_auto(&to_i915(obj->base.dev)->runtime_pm.userfault_wakeref,
msecs_to_jiffies_timeout(CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND));
i915_ttm_adjust_lru(obj);
dma_resv_unlock(bo->base.resv);
out_rpm:
if (wakeref)
intel_runtime_pm_put(&to_i915(obj->base.dev)->runtime_pm, wakeref);
return ret;
}
static int
vm_access_ttm(struct vm_area_struct *area, unsigned long addr,
void *buf, int len, int write)
{
struct drm_i915_gem_object *obj =
i915_ttm_to_gem(area->vm_private_data);
if (i915_gem_object_is_readonly(obj) && write)
return -EACCES;
return ttm_bo_vm_access(area, addr, buf, len, write);
}
static void ttm_vm_open(struct vm_area_struct *vma)
{
struct drm_i915_gem_object *obj =
i915_ttm_to_gem(vma->vm_private_data);
GEM_BUG_ON(i915_ttm_is_ghost_object(vma->vm_private_data));
i915_gem_object_get(obj);
}
static void ttm_vm_close(struct vm_area_struct *vma)
{
struct drm_i915_gem_object *obj =
i915_ttm_to_gem(vma->vm_private_data);
GEM_BUG_ON(i915_ttm_is_ghost_object(vma->vm_private_data));
i915_gem_object_put(obj);
}
static const struct vm_operations_struct vm_ops_ttm = {
.fault = vm_fault_ttm,
.access = vm_access_ttm,
.open = ttm_vm_open,
.close = ttm_vm_close,
};
static u64 i915_ttm_mmap_offset(struct drm_i915_gem_object *obj)
{
/* The ttm_bo must be allocated with I915_BO_ALLOC_USER */
GEM_BUG_ON(!drm_mm_node_allocated(&obj->base.vma_node.vm_node));
return drm_vma_node_offset_addr(&obj->base.vma_node);
}
static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
intel_wakeref_t wakeref = 0;
assert_object_held_shared(obj);
if (i915_ttm_cpu_maps_iomem(bo->resource)) {
wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm);
/* userfault_count is protected by obj lock and rpm wakeref. */
if (obj->userfault_count) {
spin_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock);
list_del(&obj->userfault_link);
spin_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock);
obj->userfault_count = 0;
}
}
GEM_WARN_ON(obj->userfault_count);
ttm_bo_unmap_virtual(i915_gem_to_ttm(obj));
if (wakeref)
intel_runtime_pm_put(&to_i915(obj->base.dev)->runtime_pm, wakeref);
}
static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
.name = "i915_gem_object_ttm",
.flags = I915_GEM_OBJECT_IS_SHRINKABLE |
I915_GEM_OBJECT_SELF_MANAGED_SHRINK_LIST,
.get_pages = i915_ttm_get_pages,
.put_pages = i915_ttm_put_pages,
.truncate = i915_ttm_truncate,
.shrink = i915_ttm_shrink,
.adjust_lru = i915_ttm_adjust_lru,
.delayed_free = i915_ttm_delayed_free,
.migrate = i915_ttm_migrate,
.mmap_offset = i915_ttm_mmap_offset,
.unmap_virtual = i915_ttm_unmap_virtual,
.mmap_ops = &vm_ops_ttm,
};
void i915_ttm_bo_destroy(struct ttm_buffer_object *bo)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
i915_gem_object_release_memory_region(obj);
mutex_destroy(&obj->ttm.get_io_page.lock);
if (obj->ttm.created) {
/*
* We freely manage the shrinker LRU outide of the mm.pages life
* cycle. As a result when destroying the object we should be
* extra paranoid and ensure we remove it from the LRU, before
* we free the object.
*
* Touching the ttm_shrinkable outside of the object lock here
* should be safe now that the last GEM object ref was dropped.
*/
if (obj->mm.ttm_shrinkable)
i915_gem_object_make_unshrinkable(obj);
i915_ttm_backup_free(obj);
/* This releases all gem object bindings to the backend. */
__i915_gem_free_object(obj);
call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
} else {
__i915_gem_object_fini(obj);
}
}
/*
* __i915_gem_ttm_object_init - Initialize a ttm-backed i915 gem object
* @mem: The initial memory region for the object.
* @obj: The gem object.
* @size: Object size in bytes.
* @flags: gem object flags.
*
* Return: 0 on success, negative error code on failure.
*/
int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
struct drm_i915_gem_object *obj,
resource_size_t offset,
resource_size_t size,
resource_size_t page_size,
unsigned int flags)
{
static struct lock_class_key lock_class;
struct drm_i915_private *i915 = mem->i915;
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = false,
};
enum ttm_bo_type bo_type;
int ret;
drm_gem_private_object_init(&i915->drm, &obj->base, size);
i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags);
obj->bo_offset = offset;
/* Don't put on a region list until we're either locked or fully initialized. */
obj->mm.region = mem;
INIT_LIST_HEAD(&obj->mm.region_link);
INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL | __GFP_NOWARN);
mutex_init(&obj->ttm.get_io_page.lock);
bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device :
ttm_bo_type_kernel;
obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);
/* Forcing the page size is kernel internal only */
GEM_BUG_ON(page_size && obj->mm.n_placements);
/*
* Keep an extra shrink pin to prevent the object from being made
* shrinkable too early. If the ttm_tt is ever allocated in shmem, we
* drop the pin. The TTM backend manages the shrinker LRU itself,
* outside of the normal mm.pages life cycle.
*/
i915_gem_object_make_unshrinkable(obj);
/*
* If this function fails, it will call the destructor, but
* our caller still owns the object. So no freeing in the
* destructor until obj->ttm.created is true.
* Similarly, in delayed_destroy, we can't call ttm_bo_put()
* until successful initialization.
*/
ret = ttm_bo_init_reserved(&i915->bdev, i915_gem_to_ttm(obj), bo_type,
&i915_sys_placement, page_size >> PAGE_SHIFT,
&ctx, NULL, NULL, i915_ttm_bo_destroy);
/*
* XXX: The ttm_bo_init_reserved() functions returns -ENOSPC if the size
* is too big to add vma. The direct function that returns -ENOSPC is
* drm_mm_insert_node_in_range(). To handle the same error as other code
* that returns -E2BIG when the size is too large, it converts -ENOSPC to
* -E2BIG.
*/
if (size >> PAGE_SHIFT > INT_MAX && ret == -ENOSPC)
ret = -E2BIG;
if (ret)
return i915_ttm_err_to_gem(ret);
obj->ttm.created = true;
i915_gem_object_release_memory_region(obj);
i915_gem_object_init_memory_region(obj, mem);
i915_ttm_adjust_domains_after_move(obj);
i915_ttm_adjust_gem_after_move(obj);
i915_gem_object_unlock(obj);
return 0;
}
static const struct intel_memory_region_ops ttm_system_region_ops = {
.init_object = __i915_gem_ttm_object_init,
.release = intel_region_ttm_fini,
};
struct intel_memory_region *
i915_gem_ttm_system_setup(struct drm_i915_private *i915,
u16 type, u16 instance)
{
struct intel_memory_region *mr;
mr = intel_memory_region_create(i915, 0,
totalram_pages() << PAGE_SHIFT,
PAGE_SIZE, 0, 0,
type, instance,
&ttm_system_region_ops);
if (IS_ERR(mr))
return mr;
intel_memory_region_set_name(mr, "system-ttm");
return mr;
}
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