[Qemu-devel] [PATCH v4 12/17] trace: dynamically allocate trace_dstate in CPUState

[Daniel P. Berrange]

The CPUState struct has a bitmap tracking which VCPU
events are currently active. This is indexed based on
the event ID values, and sized according the maximum
TraceEventVCPUID enum value.

When we start dynamically assigning IDs at runtime,
we can't statically declare a bitmap without making
an assumption about the max event count. This problem
can be solved by dynamically allocating the per-CPU
dstate bitmap.

Signed-off-by: Daniel P. Berrange <address@hidden>
---
 include/qom/cpu.h | 8 +++++---
 qom/cpu.c         | 6 +++++-
 trace/control.c   | 5 +++++
 trace/control.h   | 7 +++++++
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index ce0c406..ec5ad86 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -27,7 +27,6 @@
 #include "qemu/bitmap.h"
 #include "qemu/queue.h"
 #include "qemu/thread.h"
-#include "trace/generated-events.h"
 
 typedef int (*WriteCoreDumpFunction)(const void *buf, size_t size,
                                      void *opaque);
@@ -350,8 +349,11 @@ struct CPUState {
     struct KVMState *kvm_state;
     struct kvm_run *kvm_run;
 
-    /* Used for events with 'vcpu' and *without* the 'disabled' properties */
-    DECLARE_BITMAP(trace_dstate, TRACE_VCPU_EVENT_COUNT);
+    /* Used for events with 'vcpu' and *without* the 'disabled' properties
+     * Dynamically allocated based on bitmap requried to hold upto
+     * trace_get_vcpu_event_count() entries.
+     */
+    unsigned long *trace_dstate;
 
     /* TODO Move common fields from CPUArchState here. */
     int cpu_index; /* used by alpha TCG */
diff --git a/qom/cpu.c b/qom/cpu.c
index f783b5a..48bbf67 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -29,6 +29,7 @@
 #include "qemu/error-report.h"
 #include "sysemu/sysemu.h"
 #include "hw/qdev-properties.h"
+#include "trace/control.h"
 
 bool cpu_exists(int64_t id)
 {
@@ -350,12 +351,15 @@ static void cpu_common_initfn(Object *obj)
     qemu_mutex_init(&cpu->work_mutex);
     QTAILQ_INIT(&cpu->breakpoints);
     QTAILQ_INIT(&cpu->watchpoints);
-    bitmap_zero(cpu->trace_dstate, TRACE_VCPU_EVENT_COUNT);
+
+    cpu->trace_dstate = bitmap_new(trace_get_vcpu_event_count());
 }
 
 static void cpu_common_finalize(Object *obj)
 {
+    CPUState *cpu = CPU(obj);
     cpu_exec_exit(CPU(obj));
+    g_free(cpu->trace_dstate);
 }
 
 static int64_t cpu_common_get_arch_id(CPUState *cpu)
diff --git a/trace/control.c b/trace/control.c
index 7be654d..9704f4d 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -310,3 +310,8 @@ void trace_init_vcpu_events(void)
         }
     }
 }
+
+uint32_t trace_get_vcpu_event_count(void)
+{
+    return TRACE_VCPU_EVENT_COUNT;
+}
diff --git a/trace/control.h b/trace/control.h
index 45ee4fb..feb5397 100644
--- a/trace/control.h
+++ b/trace/control.h
@@ -235,6 +235,13 @@ char *trace_opt_parse(const char *optarg);
 void trace_init_vcpu_events(void);
 
 
+/**
+ * trace_get_vcpu_event_count:
+ *
+ * Return the number of known vcpu-specific events
+ */
+uint32_t trace_get_vcpu_event_count(void);
+
 #include "trace/control-internal.h"
 
 #endif /* TRACE__CONTROL_H */
-- 
2.7.4