# 4. Building Your Own Hardware Designs (FireSim FPGA Images)¶

This section will guide you through building an AFI image for a FireSim simulation.

## 4.1. Amazon S3 Setup¶

During the build process, the build system will need to upload a tar file to Amazon S3 in order to complete the build process using Amazon’s backend scripts (which convert the Vivado-generated tar into an AFI). The manager will create this bucket for you automatically, you just need to specify a name.

So, choose a bucket name, e.g. firesim-yourname. Bucket names must be globally unique. If you choose one that’s already taken, the manager will notice and complain when you tell it to build an AFI. To set your bucket name, open deploy/config_build.ini in your editor and under the [afibuild] header, replace

s3bucketname=firesim-yournamehere


with your own bucket name, e.g.:

s3bucketname=firesim-sagar


## 4.2. Build Recipes¶

In the deploy/config_build.ini file, you will notice that the [builds] section currently contains several lines, which indicates to the build system that you want to run all of these builds in parallel, with the parameters listed in the relevant section of the deploy/config_build_recipes.ini file. Here you can set parameters of the simulated system, and also select the type of instance on which the Vivado build will be deployed. From our experimentation, there are diminishing returns using anything above a z1d.2xlarge, so we default to that. If you do wish to use a different build instance type keep in mind that Vivado will consume in excess of 32 GiB for large designs.

To start out, let’s build a simple design, firesim-rocket-quadcore-no-nic-l2-llc4mb-ddr3. This is a design that has four cores, no nic, and uses the 4MB LLC + DDR3 memory model. To do so, comment out all of the other build entries in deploy/config_build.ini, besides the one we want. So, you should end up with something like this (a line beginning with a # is a comment):

[builds]
# this section references builds defined in config_build_recipes.ini
# if you add a build here, it will be built when you run buildafi

firesim buildafi

This will run through the entire build process, taking the Chisel RTL and producing an AFI/AGFI that runs on the FPGA. This whole process will usually take a few hours. When the build completes, you will see a directory in deploy/results-build/, named after your build parameter settings, that contains AGFI information (the AGFI_INFO file) and all of the outputs of the Vivado build process (in the cl_firesim subdirectory). Additionally, the manager will print out a path to a log file that describes everything that happened, in-detail, during this run (this is a good file to send us if you encounter problems). If you provided the manager with your email address, you will also receive an email upon build completion, that should look something like this: