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 <vilan...@ac.upc.edu>
Reviewed-by: Richard Henderson <r...@twiddle.net>
Reviewed-by: Emilio G. Cota <c...@braap.org>
---
include/qom/cpu.h | 3 +++
trace/control-target.c | 20 +++++++++++++++++---
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 31529adf2a..0f507e6f71 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -303,6 +303,8 @@ 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.
@@ -375,6 +377,7 @@ 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 6266e6380d..d30fa5df75 100644
--- 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 <vilan...@ac.upc.edu>
+ * Copyright (C) 2014-2017 Lluís Vilanova <vilan...@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.
@@ -57,6 +57,13 @@ 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)
{
@@ -69,13 +76,20 @@ 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);
}
}
