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authorLluís Vilanova <vilanova@ac.upc.edu>2017-07-04 10:38:26 +0200
committerStefan Hajnoczi <stefanha@redhat.com>2017-07-17 13:10:54 +0100
commitd43811165df75571055dab7b602526a40404a63e (patch)
treec066c9b977186ee051851703dcc7ab5814926b1c
parentd01c05c955f7736952c13d85edaae0b262b7a0a3 (diff)
trace: [tcg] Delay changes to dynamic state when translating
This keeps consistency across all decisions taken during translation when the dynamic state of a vCPU is changed in the middle of translating some guest code. Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-id: 149915750615.6295.3713699402253529487.stgit@frigg.lan Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--include/qom/cpu.h3
-rw-r--r--trace/control-target.c18
2 files changed, 19 insertions, 2 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 5f188d4c28..25eefea7ab 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -302,6 +302,8 @@ struct qemu_work_item;
* @kvm_fd: vCPU file descriptor for KVM.
* @work_mutex: Lock to prevent multiple access to queued_work_*.
* @queued_work_first: First asynchronous work pending.
+ * @trace_dstate_delayed: Delayed changes to trace_dstate (includes all changes
+ * to @trace_dstate).
* @trace_dstate: Dynamic tracing state of events for this vCPU (bitmask).
*
* State of one CPU core or thread.
@@ -372,6 +374,7 @@ struct CPUState {
struct kvm_run *kvm_run;
/* Used for events with 'vcpu' and *without* the 'disabled' properties */
+ DECLARE_BITMAP(trace_dstate_delayed, CPU_TRACE_DSTATE_MAX_EVENTS);
DECLARE_BITMAP(trace_dstate, CPU_TRACE_DSTATE_MAX_EVENTS);
/* TODO Move common fields from CPUArchState here. */
diff --git a/trace/control-target.c b/trace/control-target.c
index 99a8ed5157..31c2ed11a0 100644
--- a/trace/control-target.c
+++ b/trace/control-target.c
@@ -61,6 +61,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
}
}
+static void trace_event_synchronize_vcpu_state_dynamic(
+ CPUState *vcpu, run_on_cpu_data ignored)
+{
+ bitmap_copy(vcpu->trace_dstate, vcpu->trace_dstate_delayed,
+ CPU_TRACE_DSTATE_MAX_EVENTS);
+}
+
void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
TraceEvent *ev, bool state)
{
@@ -73,13 +80,20 @@ void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
if (state_pre != state) {
if (state) {
trace_events_enabled_count++;
- set_bit(vcpu_id, vcpu->trace_dstate);
+ set_bit(vcpu_id, vcpu->trace_dstate_delayed);
(*ev->dstate)++;
} else {
trace_events_enabled_count--;
- clear_bit(vcpu_id, vcpu->trace_dstate);
+ clear_bit(vcpu_id, vcpu->trace_dstate_delayed);
(*ev->dstate)--;
}
+ /*
+ * Delay changes until next TB; we want all TBs to be built from a
+ * single set of dstate values to ensure consistency of generated
+ * tracing code.
+ */
+ async_run_on_cpu(vcpu, trace_event_synchronize_vcpu_state_dynamic,
+ RUN_ON_CPU_NULL);
}
}