[PATCH] drm/i915/gvt: Fix crash after request->hw_context change

[Chris Wilson]

Quoting Zhenyu Wang (2018-05-18 11:13:05)
> When we do shadowing, workload's request might not be allocated yet,
> so we still require shadow context's object. And when complete workload,
> delay to zero workload's request pointer after used for update guest context.

Please allocate the context earlier then. The point is that until you
do, shadow_ctx->__engine[ring_id]->state is *undefined* and this code is
still illegal. :-p

The intent is that you start tracking the lifetime of the state you are
using because the assumptions made here will not hold for much longer.
-Chris