Experimental HDL Error Injection Toggle

Overview

Enables (at build time) optional HDL hooks for advanced error injection paths during hardware simulation / validation. This is controlled by the new CLI flag:

--enable-error-injection

When supplied, the SystemVerilog configuration space template (sv/pcileech_cfgspace.coe.j2) embeds a short annotation comment inside the Advanced Error Reporting (AER) capability block noting that injection hooks are compiled in. No register layout or numeric field changes occur; only build‑time guarded HDL signals are enabled downstream.

Rationale

Some validation flows require fault scenarios (e.g. crafted AER events) without patching generated HDL. The toggle exposes internally wired stubs in a controlled, donor‑bound manner without weakening uniqueness or introducing fallback IDs.

Behavior Summary

Flag default: disabled (safe path, no injection hooks generated).
Activation requires --enable-advanced-features (implicitly set by regular advanced feature configuration that surfaces the AER capability) because the marker resides in that capability block.
Output difference is limited to two template comments:
; Optional Error Injection Control (implementation dependent)
; This build enables error injection hooks in HDL (not represented here).
No additional writable registers are added; runtime software cannot toggle this feature—it's compile-time only.

Usage

Minimal example:

python3 -m pcileechfwgenerator.build --input donor.json --out build/ --enable-error-injection

Confirm in the generated pcileech_cfgspace.coe:

; Optional Error Injection Control (implementation dependent)
; This build enables error injection hooks in HDL (not represented here).

If the lines are absent, the flag was not active or advanced features (AER) were not enabled for the donor context.

Validation

Unit test tests/test_coe_error_injection.py asserts presence/absence of the annotation comment under strict template rendering with a minimal context. This guarantees the toggle only affects the intended template span.

Safety & Constraints

No hardcoded Vendor/Product IDs introduced; all donor uniqueness checks remain enforced.
The feature fails safely: absence of the flag simply omits the comments and HDL stubs.
Not intended for production deployment artifacts; use only in controlled validation workflows.

Future Extensions (Potential)

Parameterized selection of specific error classes to synthesize.
Optional integration with a structured stimulus interface (e.g. AXI-lite CSR gated behind the same build-time guard) if governance criteria are met.