[Intel-gfx] [PATCH v5 1/7] drm/i915/ttm: Implement a function to copy the contents of two TTM-based objects

Thomas Hellström
2021-09-21T17:51:46Z

When backing up or restoring contents of pinned objects at suspend /
resume time we need to allocate a new object as the backup. Add a function
to facilitate copies between the two. Some data needs to be copied before
the migration context is ready for operation, so make sure we can
disable accelerated copies.

v2:
- Fix a missing return value check (Matthew Auld)

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 69 +++++++++++++++++++++----
drivers/gpu/drm/i915/gem/i915_gem_ttm.h | 4 ++
2 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 2f672f06b169..22d59510d0c3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -428,6 +428,7 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
bool clear,
struct ttm_resource *dst_mem,
+ struct ttm_tt *dst_ttm,
struct sg_table *dst_st)
{
struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915),
@@ -437,14 +438,14 @@ static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
struct sg_table *src_st;
struct i915_request *rq;
- struct ttm_tt *ttm = bo->ttm;
+ struct ttm_tt *src_ttm = bo->ttm;
enum i915_cache_level src_level, dst_level;
int ret;

if (!i915->gt.migrate.context)
return -EINVAL;

- dst_level = i915_ttm_cache_level(i915, dst_mem, ttm);
+ dst_level = i915_ttm_cache_level(i915, dst_mem, dst_ttm);
if (clear) {
if (bo->type == ttm_bo_type_kernel)
return -EINVAL;
@@ -461,10 +462,10 @@ static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
}
intel_engine_pm_put(i915->gt.migrate.context->engine);
} else {
- src_st = src_man->use_tt ? i915_ttm_tt_get_st(ttm) :
+ src_st = src_man->use_tt ? i915_ttm_tt_get_st(src_ttm) :
obj->ttm.cached_io_st;

- src_level = i915_ttm_cache_level(i915, bo->resource, ttm);
+ src_level = i915_ttm_cache_level(i915, bo->resource, src_ttm);
intel_engine_pm_get(i915->gt.migrate.context->engine);
ret = intel_context_migrate_copy(i915->gt.migrate.context,
NULL, src_st->sgl, src_level,
@@ -484,11 +485,14 @@ static int i915_ttm_accel_move(struct ttm_buffer_object *bo,

static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
struct ttm_resource *dst_mem,
- struct sg_table *dst_st)
+ struct ttm_tt *dst_ttm,
+ struct sg_table *dst_st,
+ bool allow_accel)
{
- int ret;
+ int ret = -EINVAL;

- ret = i915_ttm_accel_move(bo, clear, dst_mem, dst_st);
+ if (allow_accel)
+ ret = i915_ttm_accel_move(bo, clear, dst_mem, dst_ttm, dst_st);
if (ret) {
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
struct intel_memory_region *dst_reg, *src_reg;
@@ -503,7 +507,7 @@ static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
GEM_BUG_ON(!dst_reg || !src_reg);

dst_iter = !cpu_maps_iomem(dst_mem) ?
- ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm) :
+ ttm_kmap_iter_tt_init(&_dst_iter.tt, dst_ttm) :
ttm_kmap_iter_iomap_init(&_dst_iter.io, &dst_reg->iomap,
dst_st, dst_reg->region.start);

@@ -558,7 +562,7 @@ static int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,

clear = !cpu_maps_iomem(bo->resource) && (!ttm || !ttm_tt_is_populated(ttm));
if (!(clear && ttm && !(ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)))
- __i915_ttm_move(bo, clear, dst_mem, dst_st);
+ __i915_ttm_move(bo, clear, dst_mem, bo->ttm, dst_st, true);

ttm_bo_move_sync_cleanup(bo, dst_mem);
i915_ttm_adjust_domains_after_move(obj);
@@ -973,3 +977,50 @@ i915_gem_ttm_system_setup(struct drm_i915_private *i915,
intel_memory_region_set_name(mr, "system-ttm");
return mr;
}
+
+/**
+ * i915_gem_obj_copy_ttm - Copy the contents of one ttm-based gem object to
+ * another
+ * @dst: The destination object
+ * @src: The source object
+ * @allow_accel: Allow using the blitter. Otherwise TTM memcpy is used.
+ * @intr: Whether to perform waits interruptible:
+ *
+ * Note: The caller is responsible for assuring that the underlying
+ * TTM objects are populated if needed and locked.
+ *
+ * Return: Zero on success. Negative error code on error. If @intr == true,
+ * then it may return -ERESTARTSYS or -EINTR.
+ */
+int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
+ struct drm_i915_gem_object *src,
+ bool allow_accel, bool intr)
+{
+ struct ttm_buffer_object *dst_bo = i915_gem_to_ttm(dst);
+ struct ttm_buffer_object *src_bo = i915_gem_to_ttm(src);
+ struct ttm_operation_ctx ctx = {
+ .interruptible = intr,
+ };
+ struct sg_table *dst_st;
+ int ret;
+
+ assert_object_held(dst);
+ assert_object_held(src);
+
+ /*
+ * Sync for now. This will change with async moves.
+ */
+ ret = ttm_bo_wait_ctx(dst_bo, &ctx);
+ if (!ret)
+ ret = ttm_bo_wait_ctx(src_bo, &ctx);
+ if (ret)
+ return ret;
+
+ dst_st = gpu_binds_iomem(dst_bo->resource) ?
+ dst->ttm.cached_io_st : i915_ttm_tt_get_st(dst_bo->ttm);
+
+ __i915_ttm_move(src_bo, false, dst_bo->resource, dst_bo->ttm,
+ dst_st, allow_accel);
+
+ return 0;
+}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
index 40927f67b6d9..34ac78d47b0d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
@@ -46,4 +46,8 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
resource_size_t size,
resource_size_t page_size,
unsigned int flags);
+
+int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
+ struct drm_i915_gem_object *src,
+ bool allow_accel, bool intr);
#endif
--
2.31.1