UVM Configuration Database

UVM Config db

The configuration database provides access to a centralized database, where type specific information can be stored and received. config_db can contain scalar objects, class handles, queues, lists, or even virtual interfaces.

The database has both a name table and a type table and each resource is entered into both. Resources are stored in a database so that each resource can be retrieved by name or by type, and the database is globally accessible.

uvm config db get and set

uvm_config_db::set and uvm_config_db::get methods are used to store and retrieve the information from the database respectively.

uvm config db set method

void uvm_config_db#(type T = int)::set(uvm_component cntxt, string inst_name, string field_name, T value);


  • T  is the type of element being configured. Type can be scalar objects, class handles, queues, lists, or even virtual interfaces)
  • cntxt is the hierarchical starting point of where the database entry is accessible.
  • inst_name is a hierarchical path that limits the accessibility of the database entry.


top.*               – all of the scopes whose top-level component is top.
top.env.*.monitor   – all of the scopes in env that end in the monitor;

  • field_name is the label used as a lookup for the database entry
  • value is the value to be stored in the database

uvm_config_db set example

Below example shows, setting the interface handle intf, type mem_if, label mem_intf with global scope.

  mem_if intf(clk,reset);  //interface instance
  uvm_config_db#(virtual mem_if)::set(null,"*","mem_intf",intf);  //set method
uvm config db get and set
uvm config db get and set

The above diagrams illustrate how a resource whose name is mem_intf and type is mem_if is stored in the pool.

uvm config db get method

bit uvm_config_db#(type T=int)::get(uvm_component cntxt, string inst_name, string field_name, ref T value);
  • value is the variable to which the value is to be retrieved from the database

* The other fields are the same as in set method.
The method returns 1 if it is successful and 0 if there is no such resource of this type in the database.

uvm_config_db get example

Below example shows. Using the get method to get a virtual interface handle from a database and assigns it to mem_vif. If the get method fails, the fatal message will be displayed.

    virtual interface mem_if mem_vif;    //virtual interface declaration
    if( !uvm_config_db#(virtual mem_if)::get(this,"*", "mem_intf", mem_vif))
      `uvm_fatal(get_full_name(),{"virtual interface must be set for:",".mem_vif"} ); //get method

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