# DF-3770 — VERDICT

**Status: untested (runtime)** — Info divergence record; PoC phase skipped
per contract and impossible on this guest (virtio-only, no i915).

## Evidence
- Direct diff of `sys/dev/drm/i915/i915_gem_gtt.c` against Linux v4.19
  `drivers/gpu/drm/i915/i915_gem_gtt.c` shows the DFly tree deleted the
  `IS_VALLEYVIEW(dev_priv) && revision < 0xb → return 0` early-out from
  `intel_sanitize_enable_ppgtt` (v4.19 lines ~176-181; DFly file
  `i915_gem_gtt.c:136-183` has no equivalent). Captured in
  `upstream_v419_diff.txt`.
- Everything else in the function matches v4.19 modulo renames, so the
  deletion is a local divergence, not part of a larger rework.

## Impact assessment
- Hardware gate: ValleyView + `pdev->revision < 0xb` (2013 Atom SoCs,
  B0/B2 steppings). On those parts PPGTT gets enabled where upstream
  disables it → GPU faults/hangs under render load; local DoS on that
  hardware only. GPU reset machinery recovers; no corruption of kernel
  memory results from this divergence (the walkers in this file are
  bounds-correct independent of the enable bit).
- Info severity per rubric: hardening/divergence record, no demonstrated
  impact on current hardware.

## Fix
`fix.diff` restores the upstream block verbatim (adapted types).

## Fix status (batch validation)
Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest `make -j6 nativekernel KERNCONF=X86_64_GENERIC` completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.