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CVA6 - Exploring the structure through Vivado

In the context of different projects, I need to explore the architecture of the CVA6 core. Reading through the SystemVerilog code is not no easy, I’d rather like to use Vivado for that.

Vivado scripts

The CVA6 repository (https://github.com/openhwgroup/cva6) proposes a simple Makefile to generate the bitstream. Once prerequisites are installed, a simple make fpga will generate everything. However, in we open the Vivado project afterwards, it is basically empty.

Adding a software example in the Keystone framework

This post has been written with the help of @OussamaELmnaouri2001.

The Keystone framework provides some examples. The goal of this blogpost is to explain how we can add a new example and running it easily.

@OussamaELmnaouri2001 has a repository with some examples: https://github.com/OussamaELmnaouri2001/Keystone-Examples. In this tutorial, we will add addition example.

Requirements

It is assumed that the Keystone framework repository has been cloned on the host:

Debugging Keystone in QEmu

This post has been written with the help of @OussamaELmnaouri2001.

The goal of this blogpost if to show how we can play with Keystone in QEMu in three ways:

  1. Running the default framework in QEmu
  2. Debugging from the Security Monitor point of view
  3. Debugging from an enclave binary point of view

Requirements

It is assumed that the Keystone framework repository has been cloned on the host:

KEYSTONE_REPO=$PWD/keystone
git clone https://github.com/keystone-enclave/keystone
cd keystone
git checkout 88c49ee
git submodule update --init --recursive

Running the default framework in QEmu

Compiling and running QEmu

cd KEYSTONE_REPO
make -j$(nproc) 
make run

Running default examples in the emulator

Once QEmu is launched, it will boot a Buildroot-based kernel:

Running Keystone on the CVA6 RISC-V processor

Reference

Prerequisites

  • Vivado 2018.3.

  • Genesys2 FPGA board.

Building a CVA6-ready Keystone image

Note
NB: we didn’t enable the root of trust for attestation report yet (http://docs.keystone-enclave.org/en/latest/Getting-Started/Running-Keystone-on-CVA6.html#root-of-trust) as it seems we don’t need it for the moment.
Tip
Be careful of the device ID (/dev/sdc in this tutorial). You may harm your hard drive if you don’t choose the right ID.

SD card formatting

The tutorial has been tested with a 16GB SD card. The card was formatted with a GPT partition table and an ext4 partition taking the full space.

CVA6 and JIT domain tests - Setup for a fresh install

Introduction

In the context of a research project with a PhD student, we have to work on the microarchitecture of a CVA6 and make it compatible with some JIT code (VMIL'23 talk). The official CVA6 repository has recently pushed new scripts to create the SDK. As we already started our work, we want to generate the SDK with the old method on a fork of the CVA6..