drm/i915: disable 48bit full PPGTT when vGPU is active

Disable 48bit full PPGTT on vGPU too for now.
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: drm-intel-fixes@lists.freedesktop.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160906040412.1274-3-zhenyuw@linux.intel.com
(cherry picked from commit e320d400)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -122,8 +122,11 @@ int intel_sanitize_enable_ppgtt(struct drm_i915_private *dev_priv,
 	has_full_48bit_ppgtt =
 	       	IS_BROADWELL(dev_priv) || INTEL_GEN(dev_priv) >= 9;
 
-	if (intel_vgpu_active(dev_priv))
-		has_full_ppgtt = false; /* emulation is too hard */
+	if (intel_vgpu_active(dev_priv)) {
+		/* emulation is too hard */
+		has_full_ppgtt = false;
+		has_full_48bit_ppgtt = false;
+	}
 
 	if (!has_aliasing_ppgtt)
 		return 0;
@@ -158,7 +161,7 @@ int intel_sanitize_enable_ppgtt(struct drm_i915_private *dev_priv,
 		return 0;
 	}
 
-	if (INTEL_GEN(dev_priv) >= 8 && i915.enable_execlists)
+	if (INTEL_GEN(dev_priv) >= 8 && i915.enable_execlists && has_full_ppgtt)
 		return has_full_48bit_ppgtt ? 3 : 2;
 	else
 		return has_aliasing_ppgtt ? 1 : 0;