[Intel-gfx] [PATCH v3 2/5] drm/i915/wopcm: Check WOPCM layout separately from calculations

[Chris Wilson]

Quoting Michal Wajdeczko (2019-08-16 11:54:58)
> +static inline bool __check_layout(struct drm_i915_private *i915, u32 wopcm_size,
> +                                 u32 guc_wopcm_base, u32 guc_wopcm_size,
> +                                 u32 guc_fw_size, u32 huc_fw_size)
> +{
> +       const u32 ctx_rsvd = context_reserved_size(i915);
> +       u32 size;
> +
> +       size = wopcm_size - ctx_rsvd;

I didn't spot the paranoia for

if (ctx_rsvd > wopcm_size)
	return false;

Is that built in earlier? Even so, probably still wise to include it here
as well to fit in with the overflow checks.

> +       if (unlikely(range_overflows(guc_wopcm_base, guc_wopcm_size, size))) {
> +               dev_err(i915->drm.dev,
> +                       "WOPCM: invalid GuC region layout: %uK + %uK > %uK\n",
> +                       guc_wopcm_base / SZ_1K, guc_wopcm_size / SZ_1K,
> +                       size / SZ_1K);
> +               return false;
> +       }
> +
> +       size = guc_fw_size + GUC_WOPCM_RESERVED + GUC_WOPCM_STACK_RESERVED;
> +       if (unlikely(guc_wopcm_size < size)) {
> +               dev_err(i915->drm.dev, "WOPCM: no space for %s: %uK < %uK\n",
> +                       intel_uc_fw_type_repr(INTEL_UC_FW_TYPE_GUC),
> +                       guc_wopcm_size / SZ_1K, size / SZ_1K);
> +               return false;
> +       }
> +
> +       size = huc_fw_size + WOPCM_RESERVED_SIZE;
> +       if (unlikely(guc_wopcm_base < size)) {
> +               dev_err(i915->drm.dev, "WOPCM: no space for %s: %uK < %uK\n",
> +                       intel_uc_fw_type_repr(INTEL_UC_FW_TYPE_HUC),
> +                       guc_wopcm_base / SZ_1K, size / SZ_1K);
> +               return false;
> +       }
> +
> +       return check_hw_restrictions(i915, guc_wopcm_base, guc_wopcm_size,
> +                                    huc_fw_size);
>  }

Looks safely paranoid to me,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris