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[for-5.0 PATCH 06/11] replay: introduce breakpoint at the specified step
From: |
Pavel Dovgalyuk |
Subject: |
[for-5.0 PATCH 06/11] replay: introduce breakpoint at the specified step |
Date: |
Mon, 23 Dec 2019 12:47:46 +0300 |
User-agent: |
StGit/0.17.1-dirty |
From: Pavel Dovgalyuk <address@hidden>
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 <address@hidden>
Acked-by: Markus Armbruster <address@hidden>
--
v2:
- renamed replay_break qmp command into replay-break
(suggested by Eric Blake)
v7:
- introduces replay_delete_break command
v9:
- changed 'step' parameter name to 'icount'
- moved json stuff to replay.json and updated the description
(suggested by Markus Armbruster)
v10:
- updated descriptions (suggested by Markus Armbruster)
v11:
- fixed replay_break rearm bug
---
hmp-commands.hx | 34 ++++++++++++++++++
include/monitor/hmp.h | 2 +
qapi/replay.json | 36 +++++++++++++++++++
replay/replay-debugging.c | 86 +++++++++++++++++++++++++++++++++++++++++++++
replay/replay-internal.h | 4 ++
replay/replay.c | 17 +++++++++
6 files changed, 179 insertions(+)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index cfcc044ce4..3704294da8 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1930,6 +1930,40 @@ ETEXI
STEXI
@item qom-set @var{path} @var{property} @var{value}
Set QOM property @var{property} of object at location @var{path} to value
@var{value}
+ETEXI
+
+ {
+ .name = "replay_break",
+ .args_type = "icount:i",
+ .params = "icount",
+ .help = "set breakpoint at the specified instruction count",
+ .cmd = hmp_replay_break,
+ },
+
+STEXI
+@item replay_break @var{icount}
+@findex replay_break
+Set replay breakpoint at instruction count @var{icount}.
+Execution stops when the specified instruction is reached.
+There can be at most one breakpoint. When breakpoint is set, any prior
+one is removed. The breakpoint may be set only in replay mode and only
+"in the future", i.e. at instruction counts greater than the current one.
+The current instruction count can be observed with 'info replay'.
+ETEXI
+
+ {
+ .name = "replay_delete_break",
+ .args_type = "",
+ .params = "",
+ .help = "removes replay breakpoint",
+ .cmd = hmp_replay_delete_break,
+ },
+
+STEXI
+@item replay_delete_break
+@findex replay_delete_break
+Remove replay breakpoint which was previously set with replay_break.
+The command is ignored when there are no replay breakpoints.
ETEXI
{
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 783784cf10..0fd477aa13 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -154,5 +154,7 @@ void hmp_info_vm_generation_id(Monitor *mon, const QDict
*qdict);
void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict);
void hmp_info_sev(Monitor *mon, const QDict *qdict);
void hmp_info_replay(Monitor *mon, const QDict *qdict);
+void hmp_replay_break(Monitor *mon, const QDict *qdict);
+void hmp_replay_delete_break(Monitor *mon, const QDict *qdict);
#endif
diff --git a/qapi/replay.json b/qapi/replay.json
index 67f2d1f859..e3266ef3a9 100644
--- a/qapi/replay.json
+++ b/qapi/replay.json
@@ -63,3 +63,39 @@
##
{ 'command': 'query-replay',
'returns': 'ReplayInfo' }
+
+##
+# @replay-break:
+#
+# Set replay breakpoint at instruction count @icount.
+# Execution stops when the specified instruction is reached.
+# There can be at most one breakpoint. When breakpoint is set, any prior
+# one is removed. The breakpoint may be set only in replay mode and only
+# "in the future", i.e. at instruction counts greater than the current one.
+# The current instruction count can be observed with @query-replay.
+#
+# @icount: instruction count to stop at
+#
+# Since: 5.0
+#
+# Example:
+#
+# -> { "execute": "replay-break", "data": { "icount": 220414 } }
+#
+##
+{ 'command': 'replay-break', 'data': { 'icount': 'int' } }
+
+##
+# @replay-delete-break:
+#
+# Remove replay breakpoint which was set with @replay-break.
+# The command is ignored when there are no replay breakpoints.
+#
+# Since: 5.0
+#
+# Example:
+#
+# -> { "execute": "replay-delete-break" }
+#
+##
+{ 'command': 'replay-delete-break' }
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index 8cf15ebc11..166ba10d2c 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 +44,86 @@ 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);
+ error_free(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);
+ error_free(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 9ec6ce9996..86b3e943c2 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));
+ }
}
}
}
- [for-5.0 PATCH 00/11] Support for reverse debugging with GDB, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 01/11] replay: provide an accessor for rr filename, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 02/11] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 03/11] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 04/11] qapi: introduce replay.json for record/replay-related stuff, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 05/11] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 06/11] replay: introduce breakpoint at the specified step,
Pavel Dovgalyuk <=
- [for-5.0 PATCH 07/11] replay: implement replay-seek command, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 08/11] replay: flush rr queue before loading the vmstate, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 09/11] gdbstub: add reverse step support in replay mode, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 10/11] gdbstub: add reverse continue support in replay mode, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 11/11] replay: describe reverse debugging in docs/replay.txt, Pavel Dovgalyuk, 2019/12/23