drm/i915/gvt: throw error basing on execlist submit result

throw error message in elsp emulation handler basing on execlist
submit result. guest will trigger tdr process for recovering, gvt
just follow guest's desire.

v2: populate error to top of mmio emulation logic, comments from
zhenyu

Signed-off-by: Bing Niu <bing.niu@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/handlers.c

@@ -1320,7 +1320,7 @@ static int elsp_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 	int ring_id = render_mmio_to_ring_id(vgpu->gvt, offset);
 	struct intel_vgpu_execlist *execlist;
 	u32 data = *(u32 *)p_data;
-	int ret;
+	int ret = 0;
 
 	if (WARN_ON(ring_id < 0 || ring_id > I915_NUM_ENGINES - 1))
 		return -EINVAL;
@@ -1328,12 +1328,15 @@ static int elsp_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 	execlist = &vgpu->execlist[ring_id];
 
 	execlist->elsp_dwords.data[execlist->elsp_dwords.index] = data;
-	if (execlist->elsp_dwords.index == 3)
+	if (execlist->elsp_dwords.index == 3) {
 		ret = intel_vgpu_submit_execlist(vgpu, ring_id);
+		if(ret)
+			gvt_err("fail submit workload on ring %d\n", ring_id);
+	}
 
 	++execlist->elsp_dwords.index;
 	execlist->elsp_dwords.index &= 0x3;
-	return 0;
+	return ret;
 }
 
 static int ring_mode_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,