drm/vmwgfx: Add a validation module v2

Isolate the functionality needed for reservation, validation and fencing
of vmwgfx buffer objects and resources and publish an API for this.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com> #v1

1 files changed, 659 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
new file mode 100644
index 000000000000..5bc00eafe381
--- /dev/null
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
@@ -0,0 +1,659 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/**************************************************************************
+ *
+ * Copyright © 2018 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+#include <linux/slab.h>
+#include "vmwgfx_validation.h"
+#include "vmwgfx_drv.h"
+
+/**
+ * struct vmw_validation_bo_node - Buffer object validation metadata.
+ * @base: Metadata used for TTM reservation- and validation.
+ * @hash: A hash entry used for the duplicate detection hash table.
+ * @as_mob: Validate as mob.
+ * @cpu_blit: Validate for cpu blit access.
+ *
+ * Bit fields are used since these structures are allocated and freed in
+ * large numbers and space conservation is desired.
+ */
+struct vmw_validation_bo_node {
+	struct ttm_validate_buffer base;
+	struct drm_hash_item hash;
+	u32 as_mob : 1;
+	u32 cpu_blit : 1;
+};
+
+/**
+ * struct vmw_validation_res_node - Resource validation metadata.
+ * @head: List head for the resource validation list.
+ * @hash: A hash entry used for the duplicate detection hash table.
+ * @res: Reference counted resource pointer.
+ * @new_backup: Non ref-counted pointer to new backup buffer to be assigned
+ * to a resource.
+ * @new_backup_offset: Offset into the new backup mob for resources that can
+ * share MOBs.
+ * @no_buffer_needed: Kernel does not need to allocate a MOB during validation,
+ * the command stream provides a mob bind operation.
+ * @switching_backup: The validation process is switching backup MOB.
+ * @first_usage: True iff the resource has been seen only once in the current
+ * validation batch.
+ * @reserved: Whether the resource is currently reserved by this process.
+ * @private: Optionally additional memory for caller-private data.
+ *
+ * Bit fields are used since these structures are allocated and freed in
+ * large numbers and space conservation is desired.
+ */
+struct vmw_validation_res_node {
+	struct list_head head;
+	struct drm_hash_item hash;
+	struct vmw_resource *res;
+	struct vmw_buffer_object *new_backup;
+	unsigned long new_backup_offset;
+	u32 no_buffer_needed : 1;
+	u32 switching_backup : 1;
+	u32 first_usage : 1;
+	u32 reserved : 1;
+	unsigned long private[0];
+};
+
+/**
+ * vmw_validation_find_bo_dup - Find a duplicate buffer object entry in the
+ * validation context's lists.
+ * @ctx: The validation context to search.
+ * @vbo: The buffer object to search for.
+ *
+ * Return: Pointer to the struct vmw_validation_bo_node referencing the
+ * duplicate, or NULL if none found.
+ */
+static struct vmw_validation_bo_node *
+vmw_validation_find_bo_dup(struct vmw_validation_context *ctx,
+			   struct vmw_buffer_object *vbo)
+{
+	struct  vmw_validation_bo_node *bo_node = NULL;
+
+	if (!ctx->merge_dups)
+		return NULL;
+
+	if (ctx->ht) {
+		struct drm_hash_item *hash;
+
+		if (!drm_ht_find_item(ctx->ht, (unsigned long) vbo, &hash))
+			bo_node = container_of(hash, typeof(*bo_node), hash);
+	} else {
+		struct  vmw_validation_bo_node *entry;
+
+		list_for_each_entry(entry, &ctx->bo_list, base.head) {
+			if (entry->base.bo == &vbo->base) {
+				bo_node = entry;
+				break;
+			}
+		}
+	}
+
+	return bo_node;
+}
+
+/**
+ * vmw_validation_find_res_dup - Find a duplicate resource entry in the
+ * validation context's lists.
+ * @ctx: The validation context to search.
+ * @vbo: The buffer object to search for.
+ *
+ * Return: Pointer to the struct vmw_validation_bo_node referencing the
+ * duplicate, or NULL if none found.
+ */
+static struct vmw_validation_res_node *
+vmw_validation_find_res_dup(struct vmw_validation_context *ctx,
+			    struct vmw_resource *res)
+{
+	struct  vmw_validation_res_node *res_node = NULL;
+
+	if (!ctx->merge_dups)
+		return NULL;
+
+	if (ctx->ht) {
+		struct drm_hash_item *hash;
+
+		if (!drm_ht_find_item(ctx->ht, (unsigned long) res, &hash))
+			res_node = container_of(hash, typeof(*res_node), hash);
+	} else {
+		struct  vmw_validation_res_node *entry;
+
+		list_for_each_entry(entry, &ctx->resource_ctx_list, head) {
+			if (entry->res == res) {
+				res_node = entry;
+				goto out;
+			}
+		}
+
+		list_for_each_entry(entry, &ctx->resource_list, head) {
+			if (entry->res == res) {
+				res_node = entry;
+				break;
+			}
+		}
+
+	}
+out:
+	return res_node;
+}
+
+/**
+ * vmw_validation_add_bo - Add a buffer object to the validation context.
+ * @ctx: The validation context.
+ * @vbo: The buffer object.
+ * @as_mob: Validate as mob, otherwise suitable for GMR operations.
+ * @cpu_blit: Validate in a page-mappable location.
+ *
+ * Return: Zero on success, negative error code otherwise.
+ */
+int vmw_validation_add_bo(struct vmw_validation_context *ctx,
+			  struct vmw_buffer_object *vbo,
+			  bool as_mob,
+			  bool cpu_blit)
+{
+	struct vmw_validation_bo_node *bo_node;
+
+	bo_node = vmw_validation_find_bo_dup(ctx, vbo);
+	if (bo_node) {
+		if (bo_node->as_mob != as_mob ||
+		    bo_node->cpu_blit != cpu_blit) {
+			DRM_ERROR("Inconsistent buffer usage.\n");
+			return -EINVAL;
+		}
+	} else {
+		struct ttm_validate_buffer *val_buf;
+		int ret;
+
+		bo_node = kmalloc(sizeof(*bo_node), GFP_KERNEL);
+		if (!bo_node)
+			return -ENOMEM;
+
+		if (ctx->ht) {
+			bo_node->hash.key = (unsigned long) vbo;
+			ret = drm_ht_insert_item(ctx->ht, &bo_node->hash);
+			if (ret) {
+				DRM_ERROR("Failed to initialize a buffer "
+					  "validation entry.\n");
+				kfree(bo_node);
+				return ret;
+			}
+		}
+		val_buf = &bo_node->base;
+		val_buf->bo = ttm_bo_reference(&vbo->base);
+		val_buf->shared = false;
+		list_add_tail(&val_buf->head, &ctx->bo_list);
+		bo_node->as_mob = as_mob;
+		bo_node->cpu_blit = cpu_blit;
+	}
+
+	return 0;
+}
+
+/**
+ * vmw_validation_add_resource - Add a resource to the validation context.
+ * @ctx: The validation context.
+ * @res: The resource.
+ * @priv_size: Size of private, additional metadata.
+ * @p_node: Output pointer of additional metadata address.
+ * @first_usage: Whether this was the first time this resource was seen.
+ *
+ * Return: Zero on success, negative error code otherwise.
+ */
+int vmw_validation_add_resource(struct vmw_validation_context *ctx,
+				struct vmw_resource *res,
+				size_t priv_size,
+				void **p_node,
+				bool *first_usage)
+{
+	struct vmw_validation_res_node *node;
+	int ret;
+
+	node = vmw_validation_find_res_dup(ctx, res);
+	if (node) {
+		node->first_usage = 0;
+		goto out_fill;
+	}
+
+	node = kzalloc(sizeof(*node) + priv_size, GFP_KERNEL);
+	if (!node) {
+		DRM_ERROR("Failed to allocate a resource validation "
+			  "entry.\n");
+		return -ENOMEM;
+	}
+
+	if (ctx->ht) {
+		node->hash.key = (unsigned long) res;
+		ret = drm_ht_insert_item(ctx->ht, &node->hash);
+		if (ret) {
+			DRM_ERROR("Failed to initialize a resource validation "
+				  "entry.\n");
+			kfree(node);
+			return ret;
+		}
+	}
+	node->res = vmw_resource_reference(res);
+	node->first_usage = 1;
+	if (!res->dev_priv->has_mob) {
+		list_add_tail(&node->head, &ctx->resource_list);
+	} else {
+		switch (vmw_res_type(res)) {
+		case vmw_res_context:
+		case vmw_res_dx_context:
+			list_add(&node->head, &ctx->resource_ctx_list);
+			break;
+		case vmw_res_cotable:
+			list_add_tail(&node->head, &ctx->resource_ctx_list);
+			break;
+		default:
+			list_add_tail(&node->head, &ctx->resource_list);
+			break;
+		}
+	}
+
+out_fill:
+	if (first_usage)
+		*first_usage = node->first_usage;
+	if (p_node)
+		*p_node = &node->private;
+
+	return 0;
+}
+
+/**
+ * vmw_validation_res_switch_backup - Register a backup MOB switch during
+ * validation.
+ * @ctx: The validation context.
+ * @val_private: The additional meta-data pointer returned when the
+ * resource was registered with the validation context. Used to identify
+ * the resource.
+ * @vbo: The new backup buffer object MOB. This buffer object needs to have
+ * already been registered with the validation context.
+ * @backup_offset: Offset into the new backup MOB.
+ */
+void vmw_validation_res_switch_backup(struct vmw_validation_context *ctx,
+				      void *val_private,
+				      struct vmw_buffer_object *vbo,
+				      unsigned long backup_offset)
+{
+	struct vmw_validation_res_node *val;
+
+	val = container_of(val_private, typeof(*val), private);
+
+	val->switching_backup = 1;
+	if (val->first_usage)
+		val->no_buffer_needed = 1;
+
+	val->new_backup = vbo;
+	val->new_backup_offset = backup_offset;
+}
+
+/**
+ * vmw_validation_res_reserve - Reserve all resources registered with this
+ * validation context.
+ * @ctx: The validation context.
+ * @intr: Use interruptible waits when possible.
+ *
+ * Return: Zero on success, -ERESTARTSYS if interrupted. Negative error
+ * code on failure.
+ */
+int vmw_validation_res_reserve(struct vmw_validation_context *ctx,
+			       bool intr)
+{
+	struct vmw_validation_res_node *val;
+	int ret = 0;
+
+	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
+
+	list_for_each_entry(val, &ctx->resource_list, head) {
+		struct vmw_resource *res = val->res;
+
+		ret = vmw_resource_reserve(res, intr, val->no_buffer_needed);
+		if (ret)
+			goto out_unreserve;
+
+		val->reserved = 1;
+		if (res->backup) {
+			struct vmw_buffer_object *vbo = res->backup;
+
+			ret = vmw_validation_add_bo
+				(ctx, vbo, vmw_resource_needs_backup(res),
+				 false);
+			if (ret)
+				goto out_unreserve;
+		}
+	}
+
+	return 0;
+
+out_unreserve:
+	vmw_validation_res_unreserve(ctx, true);
+	return ret;
+}
+
+/**
+ * vmw_validation_res_unreserve - Unreserve all reserved resources
+ * registered with this validation context.
+ * @ctx: The validation context.
+ * @backoff: Whether this is a backoff- of a commit-type operation. This
+ * is used to determine whether to switch backup MOBs or not.
+ */
+void vmw_validation_res_unreserve(struct vmw_validation_context *ctx,
+				 bool backoff)
+{
+	struct vmw_validation_res_node *val;
+
+	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
+
+	list_for_each_entry(val, &ctx->resource_list, head) {
+		if (val->reserved)
+			vmw_resource_unreserve(val->res,
+					       !backoff &&
+					       val->switching_backup,
+					       val->new_backup,
+					       val->new_backup_offset);
+	}
+}
+
+/**
+ * vmw_validation_bo_validate_single - Validate a single buffer object.
+ * @bo: The TTM buffer object base.
+ * @interruptible: Whether to perform waits interruptible if possible.
+ * @validate_as_mob: Whether to validate in MOB memory.
+ *
+ * Return: Zero on success, -ERESTARTSYS if interrupted. Negative error
+ * code on failure.
+ */
+int vmw_validation_bo_validate_single(struct ttm_buffer_object *bo,
+				      bool interruptible,
+				      bool validate_as_mob)
+{
+	struct vmw_buffer_object *vbo =
+		container_of(bo, struct vmw_buffer_object, base);
+	struct ttm_operation_ctx ctx = {
+		.interruptible = interruptible,
+		.no_wait_gpu = false
+	};
+	int ret;
+
+	if (vbo->pin_count > 0)
+		return 0;
+
+	if (validate_as_mob)
+		return ttm_bo_validate(bo, &vmw_mob_placement, &ctx);
+
+	/**
+	 * Put BO in VRAM if there is space, otherwise as a GMR.
+	 * If there is no space in VRAM and GMR ids are all used up,
+	 * start evicting GMRs to make room. If the DMA buffer can't be
+	 * used as a GMR, this will return -ENOMEM.
+	 */
+
+	ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, &ctx);
+	if (ret == 0 || ret == -ERESTARTSYS)
+		return ret;
+
+	/**
+	 * If that failed, try VRAM again, this time evicting
+	 * previous contents.
+	 */
+
+	ret = ttm_bo_validate(bo, &vmw_vram_placement, &ctx);
+	return ret;
+}
+
+/**
+ * vmw_validation_bo_validate - Validate all buffer objects registered with
+ * the validation context.
+ * @ctx: The validation context.
+ * @intr: Whether to perform waits interruptible if possible.
+ *
+ * Return: Zero on success, -ERESTARTSYS if interrupted,
+ * negative error code on failure.
+ */
+int vmw_validation_bo_validate(struct vmw_validation_context *ctx, bool intr)
+{
+	struct vmw_validation_bo_node *entry;
+	int ret;
+
+	list_for_each_entry(entry, &ctx->bo_list, base.head) {
+		if (entry->cpu_blit) {
+			struct ttm_operation_ctx ctx = {
+				.interruptible = intr,
+				.no_wait_gpu = false
+			};
+
+			ret = ttm_bo_validate(entry->base.bo,
+					      &vmw_nonfixed_placement, &ctx);
+		} else {
+			ret = vmw_validation_bo_validate_single
+			(entry->base.bo, intr, entry->as_mob);
+		}
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/**
+ * vmw_validation_res_validate - Validate all resources registered with the
+ * validation context.
+ * @ctx: The validation context.
+ * @intr: Whether to perform waits interruptible if possible.
+ *
+ * Before this function is called, all resource backup buffers must have
+ * been validated.
+ *
+ * Return: Zero on success, -ERESTARTSYS if interrupted,
+ * negative error code on failure.
+ */
+int vmw_validation_res_validate(struct vmw_validation_context *ctx, bool intr)
+{
+	struct vmw_validation_res_node *val;
+	int ret;
+
+	list_for_each_entry(val, &ctx->resource_list, head) {
+		struct vmw_resource *res = val->res;
+		struct vmw_buffer_object *backup = res->backup;
+
+		ret = vmw_resource_validate(res);
+		if (ret) {
+			if (ret != -ERESTARTSYS)
+				DRM_ERROR("Failed to validate resource.\n");
+			return ret;
+		}
+
+		/* Check if the resource switched backup buffer */
+		if (backup && res->backup && (backup != res->backup)) {
+			struct vmw_buffer_object *vbo = res->backup;
+
+			ret = vmw_validation_add_bo
+				(ctx, vbo, vmw_resource_needs_backup(res),
+				 false);
+			if (ret)
+				return ret;
+		}
+	}
+	return 0;
+}
+
+/**
+ * vmw_validation_drop_ht - Reset the hash table used for duplicate finding
+ * and unregister it from this validation context.
+ * @ctx: The validation context.
+ *
+ * The hash table used for duplicate finding is an expensive resource and
+ * may be protected by mutexes that may cause deadlocks during resource
+ * unreferencing if held. After resource- and buffer object registering,
+ * there is no longer any use for this hash table, so allow freeing it
+ * either to shorten any mutex locking time, or before resources- and
+ * buffer objects are freed during validation context cleanup.
+ */
+void vmw_validation_drop_ht(struct vmw_validation_context *ctx)
+{
+	struct vmw_validation_bo_node *entry;
+	struct vmw_validation_res_node *val;
+
+	if (!ctx->ht)
+		return;
+
+	list_for_each_entry(entry, &ctx->bo_list, base.head)
+		(void) drm_ht_remove_item(ctx->ht, &entry->hash);
+
+	list_for_each_entry(val, &ctx->resource_list, head)
+		(void) drm_ht_remove_item(ctx->ht, &val->hash);
+
+	list_for_each_entry(val, &ctx->resource_ctx_list, head)
+		(void) drm_ht_remove_item(ctx->ht, &val->hash);
+
+	ctx->ht = NULL;
+}
+
+/**
+ * vmw_validation_unref_lists - Unregister previously registered buffer
+ * object and resources.
+ * @ctx: The validation context.
+ *
+ * Note that this function may cause buffer object- and resource destructors
+ * to be invoked.
+ */
+void vmw_validation_unref_lists(struct vmw_validation_context *ctx)
+{
+	struct vmw_validation_bo_node *entry, *next;
+	struct vmw_validation_res_node *val, *val_next;
+
+	list_for_each_entry_safe(entry, next, &ctx->bo_list, base.head) {
+		list_del(&entry->base.head);
+		ttm_bo_unref(&entry->base.bo);
+		kfree(entry);
+	}
+
+	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
+	list_for_each_entry_safe(val, val_next, &ctx->resource_list, head) {
+		list_del(&val->head);
+		vmw_resource_unreference(&val->res);
+		kfree(val);
+	}
+
+	WARN_ON(!list_empty(&ctx->bo_list));
+	WARN_ON(!list_empty(&ctx->resource_list));
+	WARN_ON(!list_empty(&ctx->resource_ctx_list));
+}
+
+/**
+ * vmw_validation_prepare - Prepare a validation context for command
+ * submission.
+ * @ctx: The validation context.
+ * @mutex: The mutex used to protect resource reservation.
+ * @intr: Whether to perform waits interruptible if possible.
+ *
+ * Note that the single reservation mutex @mutex is an unfortunate
+ * construct. Ideally resource reservation should be moved to per-resource
+ * ww_mutexes.
+ * If this functions doesn't return Zero to indicate success, all resources
+ * are left unreserved but still referenced.
+ * Return: Zero on success, -ERESTARTSYS if interrupted, negative error code
+ * on error.
+ */
+int vmw_validation_prepare(struct vmw_validation_context *ctx,
+			   struct mutex *mutex,
+			   bool intr)
+{
+	int ret = 0;
+
+	if (mutex) {
+		if (intr)
+			ret = mutex_lock_interruptible(mutex);
+		else
+			mutex_lock(mutex);
+		if (ret)
+			return -ERESTARTSYS;
+	}
+
+	ctx->res_mutex = mutex;
+	ret = vmw_validation_res_reserve(ctx, intr);
+	if (ret)
+		goto out_no_res_reserve;
+
+	ret = vmw_validation_bo_reserve(ctx, intr);
+	if (ret)
+		goto out_no_bo_reserve;
+
+	ret = vmw_validation_bo_validate(ctx, intr);
+	if (ret)
+		goto out_no_validate;
+
+	ret = vmw_validation_res_validate(ctx, intr);
+	if (ret)
+		goto out_no_validate;
+
+	return 0;
+
+out_no_validate:
+	vmw_validation_bo_backoff(ctx);
+out_no_bo_reserve:
+	vmw_validation_res_unreserve(ctx, true);
+out_no_res_reserve:
+	if (mutex)
+		mutex_unlock(mutex);
+
+	return ret;
+}
+
+/**
+ * vmw_validation_revert - Revert validation actions if command submission
+ * failed.
+ *
+ * @ctx: The validation context.
+ *
+ * The caller still needs to unref resources after a call to this function.
+ */
+void vmw_validation_revert(struct vmw_validation_context *ctx)
+{
+	vmw_validation_bo_backoff(ctx);
+	vmw_validation_res_unreserve(ctx, true);
+	if (ctx->res_mutex)
+		mutex_unlock(ctx->res_mutex);
+}
+
+/**
+ * vmw_validation_cone - Commit validation actions after command submission
+ * success.
+ * @ctx: The validation context.
+ * @fence: Fence with which to fence all buffer objects taking part in the
+ * command submission.
+ *
+ * The caller does NOT need to unref resources after a call to this function.
+ */
+void vmw_validation_done(struct vmw_validation_context *ctx,
+			 struct vmw_fence_obj *fence)
+{
+	vmw_validation_bo_fence(ctx, fence);
+	vmw_validation_res_unreserve(ctx, false);
+	if (ctx->res_mutex)
+		mutex_unlock(ctx->res_mutex);
+	vmw_validation_unref_lists(ctx);
+}