LXR qemu/trace/control-target.c

   1/*
   2 * Interface for configuring and controlling the state of tracing events.
   3 *
   4 * Copyright (C) 2014-2017 Lluís Vilanova <vilanova@ac.upc.edu>
   5 *
   6 * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7 * See the COPYING file in the top-level directory.
   8 */
   9
  10#include "qemu/osdep.h"
  11#include "cpu.h"
  12#include "trace-root.h"
  13#include "trace/control.h"
  14#include "translate-all.h"
  15
  16
  17void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
  18{
  19    bool state_pre;
  20    assert(trace_event_get_state_static(ev));
  21    /*
  22     * We ignore the "vcpu" property here, since no vCPUs have been created
  23     * yet. Then dstate can only be 1 or 0.
  24     */
  25    state_pre = *ev->dstate;
  26    if (state_pre != state) {
  27        if (state) {
  28            trace_events_enabled_count++;
  29            *ev->dstate = 1;
  30        } else {
  31            trace_events_enabled_count--;
  32            *ev->dstate = 0;
  33        }
  34    }
  35}
  36
  37void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
  38{
  39    CPUState *vcpu;
  40    assert(trace_event_get_state_static(ev));
  41    if (trace_event_is_vcpu(ev) && likely(first_cpu != NULL)) {
  42        CPU_FOREACH(vcpu) {
  43            trace_event_set_vcpu_state_dynamic(vcpu, ev, state);
  44        }
  45    } else {
  46        /*
  47         * Without the "vcpu" property, dstate can only be 1 or 0. With it, we
  48         * haven't instantiated any vCPU yet, so we will set a global state
  49         * instead, and trace_init_vcpu will reconcile it afterwards.
  50         */
  51        bool state_pre = *ev->dstate;
  52        if (state_pre != state) {
  53            if (state) {
  54                trace_events_enabled_count++;
  55                *ev->dstate = 1;
  56            } else {
  57                trace_events_enabled_count--;
  58                *ev->dstate = 0;
  59            }
  60        }
  61    }
  62}
  63
  64static void trace_event_synchronize_vcpu_state_dynamic(
  65    CPUState *vcpu, run_on_cpu_data ignored)
  66{
  67    bitmap_copy(vcpu->trace_dstate, vcpu->trace_dstate_delayed,
  68                CPU_TRACE_DSTATE_MAX_EVENTS);
  69    cpu_tb_jmp_cache_clear(vcpu);
  70}
  71
  72void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
  73                                        TraceEvent *ev, bool state)
  74{
  75    uint32_t vcpu_id;
  76    bool state_pre;
  77    assert(trace_event_get_state_static(ev));
  78    assert(trace_event_is_vcpu(ev));
  79    vcpu_id = trace_event_get_vcpu_id(ev);
  80    state_pre = test_bit(vcpu_id, vcpu->trace_dstate);
  81    if (state_pre != state) {
  82        if (state) {
  83            trace_events_enabled_count++;
  84            set_bit(vcpu_id, vcpu->trace_dstate_delayed);
  85            (*ev->dstate)++;
  86        } else {
  87            trace_events_enabled_count--;
  88            clear_bit(vcpu_id, vcpu->trace_dstate_delayed);
  89            (*ev->dstate)--;
  90        }
  91        /*
  92         * Delay changes until next TB; we want all TBs to be built from a
  93         * single set of dstate values to ensure consistency of generated
  94         * tracing code.
  95         */
  96        async_run_on_cpu(vcpu, trace_event_synchronize_vcpu_state_dynamic,
  97                         RUN_ON_CPU_NULL);
  98    }
  99}
 100
 101static bool adding_first_cpu1(void)
 102{
 103    CPUState *cpu;
 104    size_t count = 0;
 105    CPU_FOREACH(cpu) {
 106        count++;
 107        if (count > 1) {
 108            return false;
 109        }
 110    }
 111    return true;
 112}
 113
 114static bool adding_first_cpu(void)
 115{
 116    bool res;
 117    cpu_list_lock();
 118    res = adding_first_cpu1();
 119    cpu_list_unlock();
 120    return res;
 121}
 122
 123void trace_init_vcpu(CPUState *vcpu)
 124{
 125    TraceEventIter iter;
 126    TraceEvent *ev;
 127    trace_event_iter_init(&iter, NULL);
 128    while ((ev = trace_event_iter_next(&iter)) != NULL) {
 129        if (trace_event_is_vcpu(ev) &&
 130            trace_event_get_state_static(ev) &&
 131            trace_event_get_state_dynamic(ev)) {
 132            if (adding_first_cpu()) {
 133                /* check preconditions */
 134                assert(*ev->dstate == 1);
 135                /* disable early-init state ... */
 136                *ev->dstate = 0;
 137                trace_events_enabled_count--;
 138                /* ... and properly re-enable */
 139                trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
 140            } else {
 141                trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
 142            }
 143        }
 144    }
 145    trace_guest_cpu_enter(vcpu);
 146}
 147