Quoting Xiaolin Zhang (2019-03-29 13:32:40) > + spin_lock(&engine->i915->vgpu.shared_page_lock); > + shared_page->ring_id = engine->id; > + for (n = 0; n < execlists_num_ports(execlists); n++) > + shared_page->descs[n] = descs[n]; > + > + __raw_i915_write32(uncore, vgtif_reg(g2v_notify), > + VGT_G2V_PV_SUBMISSION); There's no serialisation with the consumer here. The shared_page->descs[] will be clobbered by a second engine before they are read by pv. There should be a wait-for-ack here, or separate channels for each engine. In execlists, we avoid this by not dequeuing until after we get a response/ack from HW. Preemption? I guess preemption was turned off, or else you have to worry about the same engine overwriting the desc[] (if no ack). -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
