IB/mlx5: Introduce VAR object and its alloc/destroy methods

Introduce VAR object and its alloc/destroy KABI methods. The internal
implementation uses the IB core API to manage mmap/munamp calls.

Link: https://lore.kernel.org/r/20191212110928.334995-5-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -2078,6 +2078,7 @@ 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 *mdm;
 
 	switch (mentry->mmap_flag) {
@@ -2087,6 +2088,12 @@ static void mlx5_ib_mmap_free(struct rdma_user_mmap_entry *entry)
 				       mdm->size);
 		kfree(mdm);
 		break;
+	case MLX5_IB_MMAP_TYPE_VAR:
+		mutex_lock(&var_table->bitmap_lock);
+		clear_bit(mentry->page_idx, var_table->bitmap);
+		mutex_unlock(&var_table->bitmap_lock);
+		kfree(mentry);
+		break;
 	default:
 		WARN_ON(true);
 	}
@@ -2255,6 +2262,15 @@ static int mlx5_ib_mmap_offset(struct mlx5_ib_dev *dev,
 	return ret;
 }
 
+static u64 mlx5_entry_to_mmap_offset(struct mlx5_user_mmap_entry *entry)
+{
+	u16 cmd = entry->rdma_entry.start_pgoff >> 16;
+	u16 index = entry->rdma_entry.start_pgoff & 0xFFFF;
+
+	return (((index >> 8) << 16) | (cmd << MLX5_IB_MMAP_CMD_SHIFT) |
+		(index & 0xFF)) << PAGE_SHIFT;
+}
+
 static int mlx5_ib_mmap(struct ib_ucontext *ibcontext, struct vm_area_struct *vma)
 {
 	struct mlx5_ib_ucontext *context = to_mucontext(ibcontext);
@@ -6034,6 +6050,145 @@ static void mlx5_ib_cleanup_multiport_master(struct mlx5_ib_dev *dev)
 	mlx5_nic_vport_disable_roce(dev->mdev);
 }
 
+static int var_obj_cleanup(struct ib_uobject *uobject,
+			   enum rdma_remove_reason why,
+			   struct uverbs_attr_bundle *attrs)
+{
+	struct mlx5_user_mmap_entry *obj = uobject->object;
+
+	rdma_user_mmap_entry_remove(&obj->rdma_entry);
+	return 0;
+}
+
+static struct mlx5_user_mmap_entry *
+alloc_var_entry(struct mlx5_ib_ucontext *c)
+{
+	struct mlx5_user_mmap_entry *entry;
+	struct mlx5_var_table *var_table;
+	u32 page_idx;
+	int err;
+
+	var_table = &to_mdev(c->ibucontext.device)->var_table;
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&var_table->bitmap_lock);
+	page_idx = find_first_zero_bit(var_table->bitmap,
+				       var_table->num_var_hw_entries);
+	if (page_idx >= var_table->num_var_hw_entries) {
+		err = -ENOSPC;
+		mutex_unlock(&var_table->bitmap_lock);
+		goto end;
+	}
+
+	set_bit(page_idx, var_table->bitmap);
+	mutex_unlock(&var_table->bitmap_lock);
+
+	entry->address = var_table->hw_start_addr +
+				(page_idx * var_table->stride_size);
+	entry->page_idx = page_idx;
+	entry->mmap_flag = MLX5_IB_MMAP_TYPE_VAR;
+
+	err = rdma_user_mmap_entry_insert_range(
+		&c->ibucontext, &entry->rdma_entry, var_table->stride_size,
+		MLX5_IB_MMAP_OFFSET_START << 16,
+		(MLX5_IB_MMAP_OFFSET_END << 16) + (1UL << 16) - 1);
+	if (err)
+		goto err_insert;
+
+	return entry;
+
+err_insert:
+	mutex_lock(&var_table->bitmap_lock);
+	clear_bit(page_idx, var_table->bitmap);
+	mutex_unlock(&var_table->bitmap_lock);
+end:
+	kfree(entry);
+	return ERR_PTR(err);
+}
+
+static int UVERBS_HANDLER(MLX5_IB_METHOD_VAR_OBJ_ALLOC)(
+	struct uverbs_attr_bundle *attrs)
+{
+	struct ib_uobject *uobj = uverbs_attr_get_uobject(
+		attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_HANDLE);
+	struct mlx5_ib_ucontext *c;
+	struct mlx5_user_mmap_entry *entry;
+	u64 mmap_offset;
+	u32 length;
+	int err;
+
+	c = to_mucontext(ib_uverbs_get_ucontext(attrs));
+	if (IS_ERR(c))
+		return PTR_ERR(c);
+
+	entry = alloc_var_entry(c);
+	if (IS_ERR(entry))
+		return PTR_ERR(entry);
+
+	mmap_offset = mlx5_entry_to_mmap_offset(entry);
+	length = entry->rdma_entry.npages * PAGE_SIZE;
+	uobj->object = entry;
+
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_OFFSET,
+			     &mmap_offset, sizeof(mmap_offset));
+	if (err)
+		goto err;
+
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_PAGE_ID,
+			     &entry->page_idx, sizeof(entry->page_idx));
+	if (err)
+		goto err;
+
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_LENGTH,
+			     &length, sizeof(length));
+	if (err)
+		goto err;
+
+	return 0;
+
+err:
+	rdma_user_mmap_entry_remove(&entry->rdma_entry);
+	return err;
+}
+
+DECLARE_UVERBS_NAMED_METHOD(
+	MLX5_IB_METHOD_VAR_OBJ_ALLOC,
+	UVERBS_ATTR_IDR(MLX5_IB_ATTR_VAR_OBJ_ALLOC_HANDLE,
+			MLX5_IB_OBJECT_VAR,
+			UVERBS_ACCESS_NEW,
+			UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_VAR_OBJ_ALLOC_PAGE_ID,
+			   UVERBS_ATTR_TYPE(u32),
+			   UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_LENGTH,
+			   UVERBS_ATTR_TYPE(u32),
+			   UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_OFFSET,
+			    UVERBS_ATTR_TYPE(u64),
+			    UA_MANDATORY));
+
+DECLARE_UVERBS_NAMED_METHOD_DESTROY(
+	MLX5_IB_METHOD_VAR_OBJ_DESTROY,
+	UVERBS_ATTR_IDR(MLX5_IB_ATTR_VAR_OBJ_DESTROY_HANDLE,
+			MLX5_IB_OBJECT_VAR,
+			UVERBS_ACCESS_DESTROY,
+			UA_MANDATORY));
+
+DECLARE_UVERBS_NAMED_OBJECT(MLX5_IB_OBJECT_VAR,
+			    UVERBS_TYPE_ALLOC_IDR(var_obj_cleanup),
+			    &UVERBS_METHOD(MLX5_IB_METHOD_VAR_OBJ_ALLOC),
+			    &UVERBS_METHOD(MLX5_IB_METHOD_VAR_OBJ_DESTROY));
+
+static bool var_is_supported(struct ib_device *device)
+{
+	struct mlx5_ib_dev *dev = to_mdev(device);
+
+	return (MLX5_CAP_GEN_64(dev->mdev, general_obj_types) &
+			MLX5_GENERAL_OBJ_TYPES_CAP_VIRTIO_NET_Q);
+}
+
 ADD_UVERBS_ATTRIBUTES_SIMPLE(
 	mlx5_ib_dm,
 	UVERBS_OBJECT_DM,
@@ -6064,6 +6219,8 @@ static const struct uapi_definition mlx5_ib_defs[] = {
 	UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_FLOW_ACTION,
 				&mlx5_ib_flow_action),
 	UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_DM, &mlx5_ib_dm),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(MLX5_IB_OBJECT_VAR,
+				UAPI_DEF_IS_OBJ_SUPPORTED(var_is_supported)),
 	{}
 };
 

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -71,6 +71,11 @@
 
 #define MLX5_MKEY_PAGE_SHIFT_MASK __mlx5_mask(mkc, log_page_size)
 
+enum {
+	MLX5_IB_MMAP_OFFSET_START = 9,
+	MLX5_IB_MMAP_OFFSET_END = 255,
+};
+
 enum {
 	MLX5_IB_MMAP_CMD_SHIFT	= 8,
 	MLX5_IB_MMAP_CMD_MASK	= 0xff,
@@ -120,6 +125,7 @@ enum {
 
 enum mlx5_ib_mmap_type {
 	MLX5_IB_MMAP_TYPE_MEMIC = 1,
+	MLX5_IB_MMAP_TYPE_VAR = 2,
 };
 
 #define MLX5_LOG_SW_ICM_BLOCK_SIZE(dev)                                        \
@@ -563,6 +569,7 @@ struct mlx5_user_mmap_entry {
 	struct rdma_user_mmap_entry rdma_entry;
 	u8 mmap_flag;
 	u64 address;
+	u32 page_idx;
 };
 
 struct mlx5_ib_dm {

include/uapi/rdma/mlx5_user_ioctl_cmds.h

@@ -115,6 +115,22 @@ enum mlx5_ib_devx_obj_methods {
 	MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY,
 };
 
+enum mlx5_ib_var_alloc_attrs {
+	MLX5_IB_ATTR_VAR_OBJ_ALLOC_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+	MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_OFFSET,
+	MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_LENGTH,
+	MLX5_IB_ATTR_VAR_OBJ_ALLOC_PAGE_ID,
+};
+
+enum mlx5_ib_var_obj_destroy_attrs {
+	MLX5_IB_ATTR_VAR_OBJ_DESTROY_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+};
+
+enum mlx5_ib_var_obj_methods {
+	MLX5_IB_METHOD_VAR_OBJ_ALLOC = (1U << UVERBS_ID_NS_SHIFT),
+	MLX5_IB_METHOD_VAR_OBJ_DESTROY,
+};
+
 enum mlx5_ib_devx_umem_reg_attrs {
 	MLX5_IB_ATTR_DEVX_UMEM_REG_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
 	MLX5_IB_ATTR_DEVX_UMEM_REG_ADDR,
@@ -156,6 +172,7 @@ enum mlx5_ib_objects {
 	MLX5_IB_OBJECT_FLOW_MATCHER,
 	MLX5_IB_OBJECT_DEVX_ASYNC_CMD_FD,
 	MLX5_IB_OBJECT_DEVX_ASYNC_EVENT_FD,
+	MLX5_IB_OBJECT_VAR,
 };
 
 enum mlx5_ib_flow_matcher_create_attrs {