RDMA/mlx5: Add support in MEMIC operations

MEMIC buffer, in addition to regular read and write operations, can
support atomic operations from the host.

Introduce and implement new UAPI to allocate address space for MEMIC
operations such as atomic. This includes:

1. Expose new IOCTL for request mapping of MEMIC operation.
2. Hold the operations address in a list, so same operation to same DM
   will be allocated only once.
3. Manage refcount on the mlx5_ib_dm object, so it would be keep valid
   until all addresses were unmapped.

Link: https://lore.kernel.org/r/20210411122924.60230-7-leon@kernel.orgSigned-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx5/dm.c

@@ -148,16 +148,126 @@ static int mlx5_cmd_alloc_memic_op(struct mlx5_dm *dm, phys_addr_t addr,
 }
 
 static int add_dm_mmap_entry(struct ib_ucontext *context,
-			     struct mlx5_ib_dm_memic *mdm, u64 address)
+			     struct mlx5_user_mmap_entry *mentry, u8 mmap_flag,
+			     size_t size, u64 address)
 {
-	mdm->mentry.mmap_flag = MLX5_IB_MMAP_TYPE_MEMIC;
-	mdm->mentry.address = address;
+	mentry->mmap_flag = mmap_flag;
+	mentry->address = address;
+
 	return rdma_user_mmap_entry_insert_range(
-		context, &mdm->mentry.rdma_entry, mdm->base.size,
+		context, &mentry->rdma_entry, size,
 		MLX5_IB_MMAP_DEVICE_MEM << 16,
 		(MLX5_IB_MMAP_DEVICE_MEM << 16) + (1UL << 16) - 1);
 }
 
+static void mlx5_ib_dm_memic_free(struct kref *kref)
+{
+	struct mlx5_ib_dm_memic *dm =
+		container_of(kref, struct mlx5_ib_dm_memic, ref);
+	struct mlx5_ib_dev *dev = to_mdev(dm->base.ibdm.device);
+
+	mlx5_cmd_dealloc_memic(&dev->dm, dm->base.dev_addr, dm->base.size);
+	kfree(dm);
+}
+
+static int copy_op_to_user(struct mlx5_ib_dm_op_entry *op_entry,
+			   struct uverbs_attr_bundle *attrs)
+{
+	u64 start_offset;
+	u16 page_idx;
+	int err;
+
+	page_idx = op_entry->mentry.rdma_entry.start_pgoff & 0xFFFF;
+	start_offset = op_entry->op_addr & ~PAGE_MASK;
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
+			     &page_idx, sizeof(page_idx));
+	if (err)
+		return err;
+
+	return uverbs_copy_to(attrs,
+			      MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
+			      &start_offset, sizeof(start_offset));
+}
+
+static int map_existing_op(struct mlx5_ib_dm_memic *dm, u8 op,
+			   struct uverbs_attr_bundle *attrs)
+{
+	struct mlx5_ib_dm_op_entry *op_entry;
+
+	op_entry = xa_load(&dm->ops, op);
+	if (!op_entry)
+		return -ENOENT;
+
+	return copy_op_to_user(op_entry, attrs);
+}
+
+static int UVERBS_HANDLER(MLX5_IB_METHOD_DM_MAP_OP_ADDR)(
+	struct uverbs_attr_bundle *attrs)
+{
+	struct ib_uobject *uobj = uverbs_attr_get_uobject(
+		attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE);
+	struct mlx5_ib_dev *dev = to_mdev(uobj->context->device);
+	struct ib_dm *ibdm = uobj->object;
+	struct mlx5_ib_dm_memic *dm = to_memic(ibdm);
+	struct mlx5_ib_dm_op_entry *op_entry;
+	int err;
+	u8 op;
+
+	err = uverbs_copy_from(&op, attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP);
+	if (err)
+		return err;
+
+	if (!(MLX5_CAP_DEV_MEM(dev->mdev, memic_operations) & BIT(op)))
+		return -EOPNOTSUPP;
+
+	mutex_lock(&dm->ops_xa_lock);
+	err = map_existing_op(dm, op, attrs);
+	if (!err || err != -ENOENT)
+		goto err_unlock;
+
+	op_entry = kzalloc(sizeof(*op_entry), GFP_KERNEL);
+	if (!op_entry)
+		goto err_unlock;
+
+	err = mlx5_cmd_alloc_memic_op(&dev->dm, dm->base.dev_addr, op,
+				      &op_entry->op_addr);
+	if (err) {
+		kfree(op_entry);
+		goto err_unlock;
+	}
+	op_entry->op = op;
+	op_entry->dm = dm;
+
+	err = add_dm_mmap_entry(uobj->context, &op_entry->mentry,
+				MLX5_IB_MMAP_TYPE_MEMIC_OP, dm->base.size,
+				op_entry->op_addr & PAGE_MASK);
+	if (err) {
+		mlx5_cmd_dealloc_memic_op(&dev->dm, dm->base.dev_addr, op);
+		kfree(op_entry);
+		goto err_unlock;
+	}
+	/* From this point, entry will be freed by mmap_free */
+	kref_get(&dm->ref);
+
+	err = copy_op_to_user(op_entry, attrs);
+	if (err)
+		goto err_remove;
+
+	err = xa_insert(&dm->ops, op, op_entry, GFP_KERNEL);
+	if (err)
+		goto err_remove;
+	mutex_unlock(&dm->ops_xa_lock);
+
+	return 0;
+
+err_remove:
+	rdma_user_mmap_entry_remove(&op_entry->mentry.rdma_entry);
+err_unlock:
+	mutex_unlock(&dm->ops_xa_lock);
+
+	return err;
+}
+
 static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
 					   struct ib_dm_alloc_attr *attr,
 					   struct uverbs_attr_bundle *attrs)
@@ -178,6 +288,11 @@ static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
 
 	dm->base.type = MLX5_IB_UAPI_DM_TYPE_MEMIC;
 	dm->base.size = roundup(attr->length, MLX5_MEMIC_BASE_SIZE);
+	dm->base.ibdm.device = ctx->device;
+
+	kref_init(&dm->ref);
+	xa_init(&dm->ops);
+	mutex_init(&dm->ops_xa_lock);
 
 	err = mlx5_cmd_alloc_memic(dm_db, &dm->base.dev_addr,
 				   dm->base.size, attr->alignment);
@@ -187,7 +302,8 @@ static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
 	}
 
 	address = dm->base.dev_addr & PAGE_MASK;
-	err = add_dm_mmap_entry(ctx, dm, address);
+	err = add_dm_mmap_entry(ctx, &dm->mentry, MLX5_IB_MMAP_TYPE_MEMIC,
+				dm->base.size, address);
 	if (err) {
 		mlx5_cmd_dealloc_memic(dm_db, dm->base.dev_addr, dm->base.size);
 		kfree(dm);
@@ -195,10 +311,8 @@ static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
 	}
 
 	page_idx = dm->mentry.rdma_entry.start_pgoff & 0xFFFF;
-	err = uverbs_copy_to(attrs,
-			     MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,
-			     &page_idx,
-			     sizeof(page_idx));
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,
+			     &page_idx, sizeof(page_idx));
 	if (err)
 		goto err_copy;
 
@@ -231,6 +345,7 @@ static struct ib_dm *handle_alloc_dm_sw_icm(struct ib_ucontext *ctx,
 		return ERR_PTR(-ENOMEM);
 
 	dm->base.type = type;
+	dm->base.ibdm.device = ctx->device;
 
 	if (!capable(CAP_SYS_RAWIO) || !capable(CAP_NET_RAW)) {
 		err = -EPERM;
@@ -303,8 +418,22 @@ struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
 	}
 }
 
+static void dm_memic_remove_ops(struct mlx5_ib_dm_memic *dm)
+{
+	struct mlx5_ib_dm_op_entry *entry;
+	unsigned long idx;
+
+	mutex_lock(&dm->ops_xa_lock);
+	xa_for_each(&dm->ops, idx, entry) {
+		xa_erase(&dm->ops, idx);
+		rdma_user_mmap_entry_remove(&entry->mentry.rdma_entry);
+	}
+	mutex_unlock(&dm->ops_xa_lock);
+}
+
 static void mlx5_dm_memic_dealloc(struct mlx5_ib_dm_memic *dm)
 {
+	dm_memic_remove_ops(dm);
 	rdma_user_mmap_entry_remove(&dm->mentry.rdma_entry);
 }
 
@@ -344,6 +473,31 @@ static int mlx5_ib_dealloc_dm(struct ib_dm *ibdm,
 	}
 }
 
+void mlx5_ib_dm_mmap_free(struct mlx5_ib_dev *dev,
+			  struct mlx5_user_mmap_entry *mentry)
+{
+	struct mlx5_ib_dm_op_entry *op_entry;
+	struct mlx5_ib_dm_memic *mdm;
+
+	switch (mentry->mmap_flag) {
+	case MLX5_IB_MMAP_TYPE_MEMIC:
+		mdm = container_of(mentry, struct mlx5_ib_dm_memic, mentry);
+		kref_put(&mdm->ref, mlx5_ib_dm_memic_free);
+		break;
+	case MLX5_IB_MMAP_TYPE_MEMIC_OP:
+		op_entry = container_of(mentry, struct mlx5_ib_dm_op_entry,
+					mentry);
+		mdm = op_entry->dm;
+		mlx5_cmd_dealloc_memic_op(&dev->dm, mdm->base.dev_addr,
+					  op_entry->op);
+		kfree(op_entry);
+		kref_put(&mdm->ref, mlx5_ib_dm_memic_free);
+		break;
+	default:
+		WARN_ON(true);
+	}
+}
+
 ADD_UVERBS_ATTRIBUTES_SIMPLE(
 	mlx5_ib_dm, UVERBS_OBJECT_DM, UVERBS_METHOD_DM_ALLOC,
 	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_ALLOC_DM_RESP_START_OFFSET,
@@ -353,8 +507,28 @@ ADD_UVERBS_ATTRIBUTES_SIMPLE(
 	UVERBS_ATTR_CONST_IN(MLX5_IB_ATTR_ALLOC_DM_REQ_TYPE,
 			     enum mlx5_ib_uapi_dm_type, UA_OPTIONAL));
 
+DECLARE_UVERBS_NAMED_METHOD(
+	MLX5_IB_METHOD_DM_MAP_OP_ADDR,
+	UVERBS_ATTR_IDR(MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE,
+			UVERBS_OBJECT_DM,
+			UVERBS_ACCESS_READ,
+			UA_MANDATORY),
+	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP,
+			   UVERBS_ATTR_TYPE(u8),
+			   UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
+			    UVERBS_ATTR_TYPE(u64),
+			    UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
+			    UVERBS_ATTR_TYPE(u16),
+			    UA_OPTIONAL));
+
+DECLARE_UVERBS_GLOBAL_METHODS(UVERBS_OBJECT_DM,
+			      &UVERBS_METHOD(MLX5_IB_METHOD_DM_MAP_OP_ADDR));
+
 const struct uapi_definition mlx5_ib_dm_defs[] = {
 	UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_DM, &mlx5_ib_dm),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_DM),
 	{},
 };
 

drivers/infiniband/hw/mlx5/dm.h

@@ -18,9 +18,19 @@ struct mlx5_ib_dm {
 	size_t			size;
 };
 
+struct mlx5_ib_dm_op_entry {
+	struct mlx5_user_mmap_entry	mentry;
+	phys_addr_t			op_addr;
+	struct mlx5_ib_dm_memic		*dm;
+	u8				op;
+};
+
 struct mlx5_ib_dm_memic {
 	struct mlx5_ib_dm           base;
 	struct mlx5_user_mmap_entry mentry;
+	struct xarray               ops;
+	struct mutex                ops_xa_lock;
+	struct kref                 ref;
 };
 
 struct mlx5_ib_dm_icm {
@@ -47,6 +57,8 @@ struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
 			       struct ib_ucontext *context,
 			       struct ib_dm_alloc_attr *attr,
 			       struct uverbs_attr_bundle *attrs);
+void mlx5_ib_dm_mmap_free(struct mlx5_ib_dev *dev,
+			  struct mlx5_user_mmap_entry *mentry);
 void mlx5_cmd_dealloc_memic(struct mlx5_dm *dm, phys_addr_t addr,
 			    u64 length);
 void mlx5_cmd_dealloc_memic_op(struct mlx5_dm *dm, phys_addr_t addr,

drivers/infiniband/hw/mlx5/main.c

@@ -2088,14 +2088,11 @@ static void mlx5_ib_mmap_free(struct rdma_user_mmap_entry *entry)
 	struct mlx5_user_mmap_entry *mentry = to_mmmap(entry);
 	struct mlx5_ib_dev *dev = to_mdev(entry->ucontext->device);
 	struct mlx5_var_table *var_table = &dev->var_table;
-	struct mlx5_ib_dm_memic *mdm;
 
 	switch (mentry->mmap_flag) {
 	case MLX5_IB_MMAP_TYPE_MEMIC:
-		mdm = container_of(mentry, struct mlx5_ib_dm_memic, mentry);
-		mlx5_cmd_dealloc_memic(&dev->dm, mdm->base.dev_addr,
-				       mdm->base.size);
-		kfree(mdm);
+	case MLX5_IB_MMAP_TYPE_MEMIC_OP:
+		mlx5_ib_dm_mmap_free(dev, mentry);
 		break;
 	case MLX5_IB_MMAP_TYPE_VAR:
 		mutex_lock(&var_table->bitmap_lock);

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -166,6 +166,7 @@ enum mlx5_ib_mmap_type {
 	MLX5_IB_MMAP_TYPE_VAR = 2,
 	MLX5_IB_MMAP_TYPE_UAR_WC = 3,
 	MLX5_IB_MMAP_TYPE_UAR_NC = 4,
+	MLX5_IB_MMAP_TYPE_MEMIC_OP = 5,
 };
 
 struct mlx5_bfreg_info {

include/uapi/rdma/mlx5_user_ioctl_cmds.h

@@ -41,6 +41,17 @@ enum mlx5_ib_create_flow_action_attrs {
 	MLX5_IB_ATTR_CREATE_FLOW_ACTION_FLAGS = (1U << UVERBS_ID_NS_SHIFT),
 };
 
+enum mlx5_ib_dm_methods {
+	MLX5_IB_METHOD_DM_MAP_OP_ADDR  = (1U << UVERBS_ID_NS_SHIFT),
+};
+
+enum mlx5_ib_dm_map_op_addr_attrs {
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP,
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
+};
+
 enum mlx5_ib_alloc_dm_attrs {
 	MLX5_IB_ATTR_ALLOC_DM_RESP_START_OFFSET = (1U << UVERBS_ID_NS_SHIFT),
 	MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,