replay: introduce breakpoint at the specified step

This patch introduces replay_break, replay_delete_break
qmp and hmp commands.
These commands allow stopping at the specified instruction.
It may be useful for debugging when there are some known
events that should be investigated.
replay_break command has one argument - number of instructions
executed since the start of the replay.
replay_delete_break removes previously set breakpoint.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>

--

v4 changes:
 - removed useless error_free call
Message-Id: <160174520606.12451.7056879546045599378.stgit@pasha-ThinkPad-X280>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Pavel Dovgalyuk 2020-10-03 20:13:26 +03:00 committed by Paolo Bonzini
parent e3b09ad2b6
commit e751067179
6 changed files with 175 additions and 0 deletions

View file

@ -34,6 +34,10 @@ static char *replay_filename;
ReplayState replay_state;
static GSList *replay_blockers;
/* Replay breakpoints */
uint64_t replay_break_icount = -1ULL;
QEMUTimer *replay_break_timer;
bool replay_next_event_is(int event)
{
bool res = false;
@ -73,6 +77,13 @@ int replay_get_instructions(void)
replay_mutex_lock();
if (replay_next_event_is(EVENT_INSTRUCTION)) {
res = replay_state.instruction_count;
if (replay_break_icount != -1LL) {
uint64_t current = replay_get_current_icount();
assert(replay_break_icount >= current);
if (current + res > replay_break_icount) {
res = replay_break_icount - current;
}
}
}
replay_mutex_unlock();
return res;
@ -99,6 +110,12 @@ void replay_account_executed_instructions(void)
will be read from the log. */
qemu_notify_event();
}
/* Execution reached the break step */
if (replay_break_icount == replay_state.current_icount) {
/* Cannot make callback directly from the vCPU thread */
timer_mod_ns(replay_break_timer,
qemu_clock_get_ns(QEMU_CLOCK_REALTIME));
}
}
}
}