diff --git a/vendor/riscv_isa_sim.lock.hjson b/vendor/riscv_isa_sim.lock.hjson
new file mode 100644
index 00000000..f71b9c61
--- /dev/null
+++ b/vendor/riscv_isa_sim.lock.hjson
@@ -0,0 +1,14 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+// This file is generated by the util/vendor script. Please do not modify it
+// manually.
+
+{
+  upstream:
+  {
+    url: https://github.com/joxie/riscv-isa-sim
+    rev: c2186bf1731b2a123ccc785ce9585861d370886f
+  }
+}
diff --git a/vendor/riscv_isa_sim.vendor.hjson b/vendor/riscv_isa_sim.vendor.hjson
new file mode 100644
index 00000000..3310cfcd
--- /dev/null
+++ b/vendor/riscv_isa_sim.vendor.hjson
@@ -0,0 +1,12 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+{
+  name: "epmp-tests",
+  target_dir: "epmp-tests",
+
+  upstream: {
+    url: "https://github.com/joxie/riscv-isa-sim",
+    rev: "master",
+  },
+}