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/trace-root.h"
  13 #include "trace/control.h"
  14
  15
  16 void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
  17 {
  18     bool state_pre;
  19     assert(trace_event_get_state_static(ev));
  20     /*
  21      * We ignore the "vcpu" property here, since no vCPUs have been created
  22      * yet. Then dstate can only be 1 or 0.
  23      */
  24     state_pre = *ev->dstate;
  25     if (state_pre != state) {
  26         if (state) {
  27             trace_events_enabled_count++;
  28             *ev->dstate = 1;
  29         } else {
  30             trace_events_enabled_count--;
  31             *ev->dstate = 0;
  32         }
  33     }
  34 }
  35
  36 void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
  37 {
  38     CPUState *vcpu;
  39     assert(trace_event_get_state_static(ev));
  40     if (trace_event_is_vcpu(ev) && likely(first_cpu != NULL)) {
  41         CPU_FOREACH(vcpu) {
  42             trace_event_set_vcpu_state_dynamic(vcpu, ev, state);
  43         }
  44     } else {
  45         /*
  46          * Without the "vcpu" property, dstate can only be 1 or 0. With it, we
  47          * haven't instantiated any vCPU yet, so we will set a global state
  48          * instead, and trace_init_vcpu will reconcile it afterwards.
  49          */
  50         bool state_pre = *ev->dstate;
  51         if (state_pre != state) {
  52             if (state) {
  53                 trace_events_enabled_count++;
  54                 *ev->dstate = 1;
  55             } else {
  56                 trace_events_enabled_count--;
  57                 *ev->dstate = 0;
  58             }
  59         }
  60     }
  61 }
  62
  63 static void trace_event_synchronize_vcpu_state_dynamic(
  64     CPUState *vcpu, run_on_cpu_data ignored)
  65 {
  66     bitmap_copy(vcpu->trace_dstate, vcpu->trace_dstate_delayed,
  67                 CPU_TRACE_DSTATE_MAX_EVENTS);
  68     cpu_tb_jmp_cache_clear(vcpu);
  69 }
  70
  71 void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
  72                                         TraceEvent *ev, bool state)
  73 {
  74     uint32_t vcpu_id;
  75     bool state_pre;
  76     assert(trace_event_get_state_static(ev));
  77     assert(trace_event_is_vcpu(ev));
  78     vcpu_id = trace_event_get_vcpu_id(ev);
  79     state_pre = test_bit(vcpu_id, vcpu->trace_dstate);
  80     if (state_pre != state) {
  81         if (state) {
  82             trace_events_enabled_count++;
  83             set_bit(vcpu_id, vcpu->trace_dstate_delayed);
  84             (*ev->dstate)++;
  85         } else {
  86             trace_events_enabled_count--;
  87             clear_bit(vcpu_id, vcpu->trace_dstate_delayed);
  88             (*ev->dstate)--;
  89         }
  90         if (vcpu->created) {
  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         } else {
  99             trace_event_synchronize_vcpu_state_dynamic(vcpu, RUN_ON_CPU_NULL);
 100         }
 101     }
 102 }
 103
 104 static bool adding_first_cpu1(void)
 105 {
 106     CPUState *cpu;
 107     size_t count = 0;
 108     CPU_FOREACH(cpu) {
 109         count++;
 110         if (count > 1) {
 111             return false;
 112         }
 113     }
 114     return true;
 115 }
 116
 117 static bool adding_first_cpu(void)
 118 {
 119     bool res;
 120     cpu_list_lock();
 121     res = adding_first_cpu1();
 122     cpu_list_unlock();
 123     return res;
 124 }
 125
 126 void trace_init_vcpu(CPUState *vcpu)
 127 {
 128     TraceEventIter iter;
 129     TraceEvent *ev;
 130     trace_event_iter_init_all(&iter);
 131     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 132         if (trace_event_is_vcpu(ev) &&
 133             trace_event_get_state_static(ev) &&
 134             trace_event_get_state_dynamic(ev)) {
 135             if (adding_first_cpu()) {
 136                 /* check preconditions */
 137                 assert(*ev->dstate == 1);
 138                 /* disable early-init state ... */
 139                 *ev->dstate = 0;
 140                 trace_events_enabled_count--;
 141                 /* ... and properly re-enable */
 142                 trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
 143             } else {
 144                 trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
 145             }
 146         }
 147     }
 148     trace_guest_cpu_enter(vcpu);
 149 }