[doc] Add verification overview

doc/01_overview/index.rst

@@ -14,3 +14,4 @@ Read on for more information Ibex in general: what standards it implements, what
    compliance
    targets
    licensing
+   verification_overview

doc/01_overview/verification_overview.rst

@@ -0,0 +1,20 @@
+Verification Overview
+=====================
+
+Ibex is verified using a :ref:`UVM based testbench<verification>` that employs a :ref:`co-simulation methodology<cosim>` to cross-check Ibex execution against an ISS reference model (`Spike <https://github.com/lowRISC/riscv-isa-sim>`_).
+The testbench runs binaries built from source produced by the `RISC-DV <https://github.com/chipsalliance/riscv-dv>`_ random instruction generator.
+Additional stimulus is provided in the form of randomized memory timings, memory errors, interrupts and debug requests by the testbench.
+A comprehensive :ref:`testplan<testplan>` and :ref:`coverage plan<coverage-plan>` are implemented.
+
+Verification Status
+-------------------
+
+Ibex has a large number of parameters resulting in a large number of possible configurations.
+The configuration space is too large to fully verify the design for all possible parameter sets.
+To manage this complexity regressions runs and verification closure target a number of :ref:`supported configurations<ibex-config>`.
+
+Current verification closure effort is focussed on the ``opentitan`` configuration and is the only configuration with nightly regression runs.
+Verification maturity is tracked via :ref:`verification_stages` that are `defined by the OpenTitan project <https://docs.opentitan.org/doc/project/development_stages/#hardware-verification-stages-v>`_.
+Ibex has achieved **V2S** for the `opentitan` configuration, broadly this means verification is almost complete (over 90% code and functional coverage hit with over 90% regression pass rate with test plan and coverage plan fully implemented) but not yet closed.
+
+Nightly regression results are not yet published but we aim to do this soon.

doc/03_reference/verification.rst

@@ -1,3 +1,5 @@
+.. _verification:
+
 Verification
 ============