drm/amdgpu: Enable clear page functionality

Add clear page support in vram memory region.

v1(Christian):
  - Dont handle clear page as TTM flag since when moving the BO back
    in from GTT again we don't need that.
  - Make a specialized version of amdgpu_fill_buffer() which only
    clears the VRAM areas which are not already cleared
  - Drop the TTM_PL_FLAG_WIPE_ON_RELEASE check in
    amdgpu_object.c

v2:
  - Modify the function name amdgpu_ttm_* (Alex)
  - Drop the delayed parameter (Christian)
  - handle amdgpu_res_cleared(&cursor) just above the size
    calculation (Christian)
  - Use AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE for clearing the buffers
    in the free path to properly wait for fences etc.. (Christian)

v3(Christian):
  - Remove buffer clear code in VRAM manager instead change the
    AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE handling to set
    the DRM_BUDDY_CLEARED flag.
  - Remove ! from amdgpu_res_cleared(&cursor) check.

v4(Christian):
  - vres flag setting move to vram manager file
  - use dma_fence_get_stub in amdgpu_ttm_clear_buffer function
  - make fence a mandatory parameter and drop the if and the get/put dance
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Acked-by: Felix Kuehling <felix.kuehling@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419063538.11957-2-Arunpravin.PaneerSelvam@amd.comSigned-off-by: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

@@ -39,6 +39,7 @@
 #include "amdgpu.h"
 #include "amdgpu_trace.h"
 #include "amdgpu_amdkfd.h"
+#include "amdgpu_vram_mgr.h"
 
 /**
  * DOC: amdgpu_object
@@ -601,8 +602,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
 	if (!amdgpu_bo_support_uswc(bo->flags))
 		bo->flags &= ~AMDGPU_GEM_CREATE_CPU_GTT_USWC;
 
-	if (adev->ras_enabled)
-		bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
+	bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
 
 	bo->tbo.bdev = &adev->mman.bdev;
 	if (bp->domain & (AMDGPU_GEM_DOMAIN_GWS | AMDGPU_GEM_DOMAIN_OA |
@@ -634,7 +634,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
 	    bo->tbo.resource->mem_type == TTM_PL_VRAM) {
 		struct dma_fence *fence;
 
-		r = amdgpu_fill_buffer(bo, 0, bo->tbo.base.resv, &fence, true);
+		r = amdgpu_ttm_clear_buffer(bo, bo->tbo.base.resv, &fence);
 		if (unlikely(r))
 			goto fail_unreserve;
 
@@ -1365,8 +1365,9 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
 	if (WARN_ON_ONCE(!dma_resv_trylock(bo->base.resv)))
 		return;
 
-	r = amdgpu_fill_buffer(abo, AMDGPU_POISON, bo->base.resv, &fence, true);
+	r = amdgpu_fill_buffer(abo, 0, bo->base.resv, &fence, true);
 	if (!WARN_ON(r)) {
+		amdgpu_vram_mgr_set_cleared(bo->resource);
 		amdgpu_bo_fence(abo, fence, false);
 		dma_fence_put(fence);
 	}

drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h

@@ -164,4 +164,29 @@ static inline void amdgpu_res_next(struct amdgpu_res_cursor *cur, uint64_t size)
 	}
 }
 
+/**
+ * amdgpu_res_cleared - check if blocks are cleared
+ *
+ * @cur: the cursor to extract the block
+ *
+ * Check if the @cur block is cleared
+ */
+static inline bool amdgpu_res_cleared(struct amdgpu_res_cursor *cur)
+{
+	struct drm_buddy_block *block;
+
+	switch (cur->mem_type) {
+	case TTM_PL_VRAM:
+		block = cur->node;
+
+		if (!amdgpu_vram_mgr_is_cleared(block))
+			return false;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
 #endif

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

@@ -378,11 +378,12 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo,
 	    (abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) {
 		struct dma_fence *wipe_fence = NULL;
 
-		r = amdgpu_fill_buffer(abo, AMDGPU_POISON, NULL, &wipe_fence,
-					false);
+		r = amdgpu_fill_buffer(abo, 0, NULL, &wipe_fence,
+				       false);
 		if (r) {
 			goto error;
 		} else if (wipe_fence) {
+			amdgpu_vram_mgr_set_cleared(bo->resource);
 			dma_fence_put(fence);
 			fence = wipe_fence;
 		}
@@ -2215,6 +2216,71 @@ static int amdgpu_ttm_fill_mem(struct amdgpu_ring *ring, uint32_t src_data,
 	return 0;
 }
 
+/**
+ * amdgpu_ttm_clear_buffer - clear memory buffers
+ * @bo: amdgpu buffer object
+ * @resv: reservation object
+ * @fence: dma_fence associated with the operation
+ *
+ * Clear the memory buffer resource.
+ *
+ * Returns:
+ * 0 for success or a negative error code on failure.
+ */
+int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
+			    struct dma_resv *resv,
+			    struct dma_fence **fence)
+{
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+	struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
+	struct amdgpu_res_cursor cursor;
+	u64 addr;
+	int r;
+
+	if (!adev->mman.buffer_funcs_enabled)
+		return -EINVAL;
+
+	if (!fence)
+		return -EINVAL;
+
+	*fence = dma_fence_get_stub();
+
+	amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
+
+	mutex_lock(&adev->mman.gtt_window_lock);
+	while (cursor.remaining) {
+		struct dma_fence *next = NULL;
+		u64 size;
+
+		if (amdgpu_res_cleared(&cursor)) {
+			amdgpu_res_next(&cursor, cursor.size);
+			continue;
+		}
+
+		/* Never clear more than 256MiB at once to avoid timeouts */
+		size = min(cursor.size, 256ULL << 20);
+
+		r = amdgpu_ttm_map_buffer(&bo->tbo, bo->tbo.resource, &cursor,
+					  1, ring, false, &size, &addr);
+		if (r)
+			goto err;
+
+		r = amdgpu_ttm_fill_mem(ring, 0, addr, size, resv,
+					&next, true, true);
+		if (r)
+			goto err;
+
+		dma_fence_put(*fence);
+		*fence = next;
+
+		amdgpu_res_next(&cursor, size);
+	}
+err:
+	mutex_unlock(&adev->mman.gtt_window_lock);
+
+	return r;
+}
+
 int amdgpu_fill_buffer(struct amdgpu_bo *bo,
 			uint32_t src_data,
 			struct dma_resv *resv,

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h

@@ -38,8 +38,6 @@
 #define AMDGPU_GTT_MAX_TRANSFER_SIZE	512
 #define AMDGPU_GTT_NUM_TRANSFER_WINDOWS	2
 
-#define AMDGPU_POISON	0xd0bed0be
-
 extern const struct attribute_group amdgpu_vram_mgr_attr_group;
 extern const struct attribute_group amdgpu_gtt_mgr_attr_group;
 
@@ -155,6 +153,9 @@ int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
 			       uint64_t size, bool tmz,
 			       struct dma_resv *resv,
 			       struct dma_fence **f);
+int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
+			    struct dma_resv *resv,
+			    struct dma_fence **fence);
 int amdgpu_fill_buffer(struct amdgpu_bo *bo,
 			uint32_t src_data,
 			struct dma_resv *resv,

drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c

@@ -450,6 +450,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 {
 	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
 	struct amdgpu_device *adev = to_amdgpu_device(mgr);
+	struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo);
 	u64 vis_usage = 0, max_bytes, min_block_size;
 	struct amdgpu_vram_mgr_resource *vres;
 	u64 size, remaining_size, lpfn, fpfn;
@@ -501,6 +502,9 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 	if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
 		vres->flags |= DRM_BUDDY_CONTIGUOUS_ALLOCATION;
 
+	if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED)
+		vres->flags |= DRM_BUDDY_CLEAR_ALLOCATION;
+
 	if (fpfn || lpfn != mgr->mm.size)
 		/* Allocate blocks in desired range */
 		vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
@@ -604,7 +608,7 @@ static void amdgpu_vram_mgr_del(struct ttm_resource_manager *man,
 
 	amdgpu_vram_mgr_do_reserve(man);
 
-	drm_buddy_free_list(mm, &vres->blocks, 0);
+	drm_buddy_free_list(mm, &vres->blocks, vres->flags);
 	mutex_unlock(&mgr->lock);
 
 	atomic64_sub(vis_usage, &mgr->vis_usage);

drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h

@@ -53,10 +53,20 @@ static inline u64 amdgpu_vram_mgr_block_size(struct drm_buddy_block *block)
 	return (u64)PAGE_SIZE << drm_buddy_block_order(block);
 }
 
+static inline bool amdgpu_vram_mgr_is_cleared(struct drm_buddy_block *block)
+{
+	return drm_buddy_block_is_clear(block);
+}
+
 static inline struct amdgpu_vram_mgr_resource *
 to_amdgpu_vram_mgr_resource(struct ttm_resource *res)
 {
 	return container_of(res, struct amdgpu_vram_mgr_resource, base);
 }
 
+static inline void amdgpu_vram_mgr_set_cleared(struct ttm_resource *res)
+{
+	to_amdgpu_vram_mgr_resource(res)->flags |= DRM_BUDDY_CLEARED;
+}
+
 #endif