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authorPavel Dovgalyuk2020-10-03 19:13:26 +0200
committerPaolo Bonzini2020-10-06 08:34:49 +0200
commite751067179e18178d0f0ab5955b95d59e2a081de (patch)
treea4c504693aa2622de0f0f913766ddd33233e9afd /replay
parentreplay: introduce info hmp/qmp command (diff)
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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>
Diffstat (limited to 'replay')
-rw-r--r--replay/replay-debugging.c84
-rw-r--r--replay/replay-internal.h4
-rw-r--r--replay/replay.c17
3 files changed, 105 insertions, 0 deletions
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index 51a6de4e81..3dc23b84fc 100644
--- a/replay/replay-debugging.c
+++ b/replay/replay-debugging.c
@@ -12,10 +12,13 @@
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "sysemu/replay.h"
+#include "sysemu/runstate.h"
#include "replay-internal.h"
#include "monitor/hmp.h"
#include "monitor/monitor.h"
#include "qapi/qapi-commands-replay.h"
+#include "qapi/qmp/qdict.h"
+#include "qemu/timer.h"
void hmp_info_replay(Monitor *mon, const QDict *qdict)
{
@@ -41,3 +44,84 @@ ReplayInfo *qmp_query_replay(Error **errp)
retval->icount = replay_get_current_icount();
return retval;
}
+
+static void replay_break(uint64_t icount, QEMUTimerCB callback, void *opaque)
+{
+ assert(replay_mode == REPLAY_MODE_PLAY);
+ assert(replay_mutex_locked());
+ assert(replay_break_icount >= replay_get_current_icount());
+ assert(callback);
+
+ replay_break_icount = icount;
+
+ if (replay_break_timer) {
+ timer_del(replay_break_timer);
+ }
+ replay_break_timer = timer_new_ns(QEMU_CLOCK_REALTIME,
+ callback, opaque);
+}
+
+static void replay_delete_break(void)
+{
+ assert(replay_mode == REPLAY_MODE_PLAY);
+ assert(replay_mutex_locked());
+
+ if (replay_break_timer) {
+ timer_del(replay_break_timer);
+ timer_free(replay_break_timer);
+ replay_break_timer = NULL;
+ }
+ replay_break_icount = -1ULL;
+}
+
+static void replay_stop_vm(void *opaque)
+{
+ vm_stop(RUN_STATE_PAUSED);
+ replay_delete_break();
+}
+
+void qmp_replay_break(int64_t icount, Error **errp)
+{
+ if (replay_mode == REPLAY_MODE_PLAY) {
+ if (icount >= replay_get_current_icount()) {
+ replay_break(icount, replay_stop_vm, NULL);
+ } else {
+ error_setg(errp,
+ "cannot set breakpoint at the instruction in the past");
+ }
+ } else {
+ error_setg(errp, "setting the breakpoint is allowed only in play mode");
+ }
+}
+
+void hmp_replay_break(Monitor *mon, const QDict *qdict)
+{
+ int64_t icount = qdict_get_try_int(qdict, "icount", -1LL);
+ Error *err = NULL;
+
+ qmp_replay_break(icount, &err);
+ if (err) {
+ error_report_err(err);
+ return;
+ }
+}
+
+void qmp_replay_delete_break(Error **errp)
+{
+ if (replay_mode == REPLAY_MODE_PLAY) {
+ replay_delete_break();
+ } else {
+ error_setg(errp, "replay breakpoints are allowed only in play mode");
+ }
+}
+
+void hmp_replay_delete_break(Monitor *mon, const QDict *qdict)
+{
+ Error *err = NULL;
+
+ qmp_replay_delete_break(&err);
+ if (err) {
+ error_report_err(err);
+ return;
+ }
+}
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 33ac551e78..2f6145ec7c 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -94,6 +94,10 @@ extern ReplayState replay_state;
/* File for replay writing */
extern FILE *replay_file;
+/* Instruction count of the replay breakpoint */
+extern uint64_t replay_break_icount;
+/* Timer for the replay breakpoint callback */
+extern QEMUTimer *replay_break_timer;
void replay_put_byte(uint8_t byte);
void replay_put_event(uint8_t event);
diff --git a/replay/replay.c b/replay/replay.c
index 797b6a5b15..d4c228ab28 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -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));
+ }
}
}
}