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 "qemu/lockable.h"
  12 #include "cpu.h"
  13 #include "trace/trace-root.h"
  14 #include "trace/control.h"
  15
  16
  17 void 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
  37 void 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
  64 static 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     tcg_flush_jmp_cache(vcpu);
  70 }
  71
  72 void 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         if (vcpu->created) {
  92             /*
  93              * Delay changes until next TB; we want all TBs to be built from a
  94              * single set of dstate values to ensure consistency of generated
  95              * tracing code.
  96              */
  97             async_run_on_cpu(vcpu, trace_event_synchronize_vcpu_state_dynamic,
  98                              RUN_ON_CPU_NULL);
  99         } else {
 100             trace_event_synchronize_vcpu_state_dynamic(vcpu, RUN_ON_CPU_NULL);
 101         }
 102     }
 103 }
 104
 105 static bool adding_first_cpu1(void)
 106 {
 107     CPUState *cpu;
 108     size_t count = 0;
 109     CPU_FOREACH(cpu) {
 110         count++;
 111         if (count > 1) {
 112             return false;
 113         }
 114     }
 115     return true;
 116 }
 117
 118 static bool adding_first_cpu(void)
 119 {
 120     QEMU_LOCK_GUARD(&qemu_cpu_list_lock);
 121
 122     return adding_first_cpu1();
 123 }
 124
 125 void trace_init_vcpu(CPUState *vcpu)
 126 {
 127     TraceEventIter iter;
 128     TraceEvent *ev;
 129     trace_event_iter_init_all(&iter);
 130     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 131         if (trace_event_is_vcpu(ev) &&
 132             trace_event_get_state_static(ev) &&
 133             trace_event_get_state_dynamic(ev)) {
 134             if (adding_first_cpu()) {
 135                 /* check preconditions */
 136                 assert(*ev->dstate == 1);
 137                 /* disable early-init state ... */
 138                 *ev->dstate = 0;
 139                 trace_events_enabled_count--;
 140                 /* ... and properly re-enable */
 141                 trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
 142             } else {
 143                 trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
 144             }
 145         }
 146     }
 147     trace_guest_cpu_enter(vcpu);
 148 }