trace: Fix dynamic event state on vCPU hot-unplug

We need to disable per-vCPU events on a vCPU that is hot-unplugged to keep the dynamic event state global counters consistent. Signed-off-by: Lluís Vilanova <[email protected]> Message-id: [email protected] Signed-off-by: Stefan Hajnoczi <[email protected]>
pfliu · Jan 16, 2017 · 82e95ec · 82e95ec
1 parent fff895d
commit 82e95ec
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diff --git a/qom/cpu.c b/qom/cpu.c
@@ -348,6 +348,8 @@ static void cpu_common_realizefn(DeviceState *dev, Error **errp)
 static void cpu_common_unrealizefn(DeviceState *dev, Error **errp)
 {
     CPUState *cpu = CPU(dev);
+    /* NOTE: latest generic point before the cpu is fully unrealized */
+    trace_fini_vcpu(cpu);
     cpu_exec_unrealizefn(cpu);
 }
 

diff --git a/trace/control.c b/trace/control.c
@@ -259,6 +259,22 @@ void trace_init_file(const char *file)
 #endif
 }
 
+void trace_fini_vcpu(CPUState *vcpu)
+{
+    TraceEventIter iter;
+    TraceEvent *ev;
+
+    trace_event_iter_init(&iter, NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        if (trace_event_is_vcpu(ev) &&
+            trace_event_get_state_static(ev) &&
+            trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
+            /* must disable to affect the global counter */
+            trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
+        }
+    }
+}
+
 bool trace_init_backends(void)
 {
 #ifdef CONFIG_TRACE_SIMPLE

diff --git a/trace/control.h b/trace/control.h
@@ -201,6 +201,14 @@ void trace_init_file(const char *file);
  */
 void trace_init_vcpu(CPUState *vcpu);
 
+/**
+ * trace_fini_vcpu:
+ * @vcpu: Removed vCPU.
+ *
+ * Disable dynamic event state for a hot-unplugged vCPU.
+ */
+void trace_fini_vcpu(CPUState *vcpu);
+
 /**
  * trace_list_events:
  *