trace: Fix early setting of events with the "vcpu" property

Events with the "vcpu" property need to be set globally (i.e., as if they didn't
have that property) while we have not yet created any vCPU.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 149838891852.10366.11525912227070211356.stgit@frigg.lan
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/trace/control-target.c b/trace/control-target.c
index 6266e6380d22312c8d6735b041313f9dbf396b53..99a8ed5157d51502519e4ffbb587eb534806510c 100644 (file)
--- a/trace/control-target.c
+++ b/trace/control-target.c
@@ -1,7 +1,7 @@
 /*
  * Interface for configuring and controlling the state of tracing events.
  *
- * Copyright (C) 2014-2016 Lluís Vilanova <vilanova@ac.upc.edu>
+ * Copyright (C) 2014-2017 Lluís Vilanova <vilanova@ac.upc.edu>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
@@ -38,12 +38,16 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
 {
     CPUState *vcpu;
     assert(trace_event_get_state_static(ev));
-    if (trace_event_is_vcpu(ev)) {
+    if (trace_event_is_vcpu(ev) && likely(first_cpu != NULL)) {
         CPU_FOREACH(vcpu) {
             trace_event_set_vcpu_state_dynamic(vcpu, ev, state);
         }
     } else {
-        /* Without the "vcpu" property, dstate can only be 1 or 0 */
+        /*
+         * Without the "vcpu" property, dstate can only be 1 or 0. With it, we
+         * haven't instantiated any vCPU yet, so we will set a global state
+         * instead, and trace_init_vcpu will reconcile it afterwards.
+         */
         bool state_pre = *ev->dstate;
         if (state_pre != state) {
             if (state) {