* [PATCH v7 01/14] replay: don't record interrupt poll
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
@ 2020-10-03 17:12 ` Pavel Dovgalyuk
2020-10-03 17:12 ` [PATCH v7 02/14] replay: provide an accessor for rr filename Pavel Dovgalyuk
` (14 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:12 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
Interrupt poll is not a real interrupt event. It is needed only for
thread safety. This interrupt is used for i386 and converted
to hardware interrupt by cpu_handle_interrupt function.
Therefore it is not needed to be recorded, because hardware
interrupt will be recorded after converting.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
--
v4 changes:
- Condition check refactoring (suggested by Alex Bennée)
---
accel/tcg/cpu-exec.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index e10b46283c..a2b913c72f 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -430,8 +430,7 @@ static inline bool cpu_handle_halt(CPUState *cpu)
{
if (cpu->halted) {
#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
- if ((cpu->interrupt_request & CPU_INTERRUPT_POLL)
- && replay_interrupt()) {
+ if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
X86CPU *x86_cpu = X86_CPU(cpu);
qemu_mutex_lock_iothread();
apic_poll_irq(x86_cpu->apic_state);
@@ -527,6 +526,20 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
return false;
}
+/*
+ * CPU_INTERRUPT_POLL is a virtual event which gets converted into a
+ * "real" interrupt event later. It does not need to be recorded for
+ * replay purposes.
+ */
+static inline bool need_replay_interrupt(int interrupt_request)
+{
+#if defined(TARGET_I386)
+ return !(interrupt_request & CPU_INTERRUPT_POLL);
+#else
+ return true;
+#endif
+}
+
static inline bool cpu_handle_interrupt(CPUState *cpu,
TranslationBlock **last_tb)
{
@@ -588,7 +601,9 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
and via longjmp via cpu_loop_exit. */
else {
if (cc->cpu_exec_interrupt(cpu, interrupt_request)) {
- replay_interrupt();
+ if (need_replay_interrupt(interrupt_request)) {
+ replay_interrupt();
+ }
/*
* After processing the interrupt, ensure an EXCP_DEBUG is
* raised when single-stepping so that GDB doesn't miss the
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 02/14] replay: provide an accessor for rr filename
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
2020-10-03 17:12 ` [PATCH v7 01/14] replay: don't record interrupt poll Pavel Dovgalyuk
@ 2020-10-03 17:12 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 03/14] qcow2: introduce icount field for snapshots Pavel Dovgalyuk
` (13 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:12 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
This patch adds an accessor function for the name of the record/replay
log file. Adding an accessor instead of making variable global,
prevents accidental modification of this variable by other modules.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
include/sysemu/replay.h | 2 ++
replay/replay.c | 5 +++++
2 files changed, 7 insertions(+)
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index 5471bb514d..c9c896ae8d 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -72,6 +72,8 @@ void replay_start(void);
void replay_finish(void);
/*! Adds replay blocker with the specified error description */
void replay_add_blocker(Error *reason);
+/* Returns name of the replay log file */
+const char *replay_get_filename(void);
/* Processing the instructions */
diff --git a/replay/replay.c b/replay/replay.c
index 83ed9e0e24..42e82f7bc7 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -399,3 +399,8 @@ void replay_add_blocker(Error *reason)
{
replay_blockers = g_slist_prepend(replay_blockers, reason);
}
+
+const char *replay_get_filename(void)
+{
+ return replay_filename;
+}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 03/14] qcow2: introduce icount field for snapshots
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
2020-10-03 17:12 ` [PATCH v7 01/14] replay: don't record interrupt poll Pavel Dovgalyuk
2020-10-03 17:12 ` [PATCH v7 02/14] replay: provide an accessor for rr filename Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 04/14] migration: " Pavel Dovgalyuk
` (12 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
This patch introduces the icount field for saving within the snapshot.
It is required for navigation between the snapshots in record/replay mode.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Kevin Wolf <kwolf@redhat.com>
--
v7 changes:
- also fix the test which checks qcow2 snapshot extra data
---
block/qcow2-snapshot.c | 7 ++++++
block/qcow2.h | 3 +++
docs/interop/qcow2.txt | 5 ++++
tests/qemu-iotests/261 | 15 ++++++++-----
tests/qemu-iotests/261.out | 51 +++++++++++++++++++++++++++++---------------
5 files changed, 58 insertions(+), 23 deletions(-)
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 9b68690f56..d68b25e0c5 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -164,6 +164,12 @@ static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair,
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
}
+ if (sn->extra_data_size >= endof(QCowSnapshotExtraData, icount)) {
+ sn->icount = be64_to_cpu(extra.icount);
+ } else {
+ sn->icount = -1ULL;
+ }
+
if (sn->extra_data_size > sizeof(extra)) {
uint64_t extra_data_end;
size_t unknown_extra_data_size;
@@ -333,6 +339,7 @@ int qcow2_write_snapshots(BlockDriverState *bs)
memset(&extra, 0, sizeof(extra));
extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size);
extra.disk_size = cpu_to_be64(sn->disk_size);
+ extra.icount = cpu_to_be64(sn->icount);
id_str_size = strlen(sn->id_str);
name_size = strlen(sn->name);
diff --git a/block/qcow2.h b/block/qcow2.h
index b71e444fca..125ea9679b 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -206,6 +206,7 @@ typedef struct QEMU_PACKED QCowSnapshotHeader {
typedef struct QEMU_PACKED QCowSnapshotExtraData {
uint64_t vm_state_size_large;
uint64_t disk_size;
+ uint64_t icount;
} QCowSnapshotExtraData;
@@ -219,6 +220,8 @@ typedef struct QCowSnapshot {
uint32_t date_sec;
uint32_t date_nsec;
uint64_t vm_clock_nsec;
+ /* icount value for the moment when snapshot was taken */
+ uint64_t icount;
/* Size of all extra data, including QCowSnapshotExtraData if available */
uint32_t extra_data_size;
/* Data beyond QCowSnapshotExtraData, if any */
diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
index 7da0d81df8..0463f761ef 100644
--- a/docs/interop/qcow2.txt
+++ b/docs/interop/qcow2.txt
@@ -707,6 +707,11 @@ Snapshot table entry:
Byte 48 - 55: Virtual disk size of the snapshot in bytes
+ Byte 56 - 63: icount value which corresponds to
+ the record/replay instruction count
+ when the snapshot was taken. Set to -1
+ if icount was disabled
+
Version 3 images must include extra data at least up to
byte 55.
diff --git a/tests/qemu-iotests/261 b/tests/qemu-iotests/261
index ddcb04f285..848ffa760d 100755
--- a/tests/qemu-iotests/261
+++ b/tests/qemu-iotests/261
@@ -91,7 +91,10 @@ print_snapshot_table()
if [ $extra_len -ge 16 ]; then
echo " Disk size: $(peek_file_be "$1" $((extra_ofs + 8)) 8)"
fi
- if [ $extra_len -gt 16 ]; then
+ if [ $extra_len -ge 24 ]; then
+ echo " Icount: $(peek_file_be "$1" $((extra_ofs + 16)) 8)"
+ fi
+ if [ $extra_len -gt 24 ]; then
echo ' Unknown extra data:' \
"$(peek_file_raw "$1" $((extra_ofs + 16)) $((extra_len - 16)) \
| tr -d '\0')"
@@ -198,12 +201,12 @@ truncate -s 0 "$TEST_DIR/sn0-extra"
truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn0-pre") - 40)) \
"$TEST_DIR/sn0-post"
-# Set sn1's extra data size to 42
-poke_file "$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x2a'
-truncate -s 42 "$TEST_DIR/sn1-extra"
-poke_file "$TEST_DIR/sn1-extra" 16 'very important data'
+# Set sn1's extra data size to 50
+poke_file "$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x32'
+truncate -s 50 "$TEST_DIR/sn1-extra"
+poke_file "$TEST_DIR/sn1-extra" 24 'very important data'
# Grow sn1-post to pad
-truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn1-pre") - 82)) \
+truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn1-pre") - 90)) \
"$TEST_DIR/sn1-post"
# Set sn2's extra data size to 8
diff --git a/tests/qemu-iotests/261.out b/tests/qemu-iotests/261.out
index 2600354566..612433ae40 100644
--- a/tests/qemu-iotests/261.out
+++ b/tests/qemu-iotests/261.out
@@ -12,9 +12,10 @@ Snapshots in TEST_DIR/t.IMGFMT.v2.orig:
[1]
ID: 2
Name: sn1
- Extra data size: 42
+ Extra data size: 50
VM state size: 0
Disk size: 67108864
+ Icount: 0
Unknown extra data: very important data
[2]
ID: 3
@@ -29,22 +30,25 @@ Snapshots in TEST_DIR/t.IMGFMT.v3.orig:
[0]
ID: 1
Name: sn0
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
[1]
ID: 2
Name: sn1
- Extra data size: 42
+ Extra data size: 50
VM state size: 0
Disk size: 67108864
+ Icount: 0
Unknown extra data: very important data
[2]
ID: 3
Name: sn2
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
=== Repair botched v3 ===
@@ -61,22 +65,25 @@ Snapshots in TEST_DIR/t.IMGFMT:
[0]
ID: 1
Name: sn0
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
[1]
ID: 2
Name: sn1
- Extra data size: 42
+ Extra data size: 50
VM state size: 0
Disk size: 67108864
+ Icount: 0
Unknown extra data: very important data
[2]
ID: 3
Name: sn2
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
=== Add new snapshot ===
@@ -85,28 +92,32 @@ Snapshots in TEST_DIR/t.IMGFMT:
[0]
ID: 1
Name: sn0
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
[1]
ID: 2
Name: sn1
- Extra data size: 42
+ Extra data size: 50
VM state size: 0
Disk size: 67108864
+ Icount: 0
Unknown extra data: very important data
[2]
ID: 3
Name: sn2
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
[3]
ID: 4
Name: sn3
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 0
=== Remove different snapshots ===
@@ -116,16 +127,18 @@ Snapshots in TEST_DIR/t.IMGFMT:
[0]
ID: 2
Name: sn1
- Extra data size: 42
+ Extra data size: 50
VM state size: 0
Disk size: 67108864
+ Icount: 0
Unknown extra data: very important data
[1]
ID: 3
Name: sn2
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
--- sn1 ---
No errors were found on the image.
@@ -133,15 +146,17 @@ Snapshots in TEST_DIR/t.IMGFMT:
[0]
ID: 1
Name: sn0
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
[1]
ID: 3
Name: sn2
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
--- sn2 ---
No errors were found on the image.
@@ -149,15 +164,17 @@ Snapshots in TEST_DIR/t.IMGFMT:
[0]
ID: 1
Name: sn0
- Extra data size: 16
+ Extra data size: 24
VM state size: 0
Disk size: 67108864
+ Icount: 18446744073709551615
[1]
ID: 2
Name: sn1
- Extra data size: 42
+ Extra data size: 50
VM state size: 0
Disk size: 67108864
+ Icount: 0
Unknown extra data: very important data
=== Reject too much unknown extra data ===
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 04/14] migration: introduce icount field for snapshots
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (2 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 03/14] qcow2: introduce icount field for snapshots Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 05/14] qapi: introduce replay.json for record/replay-related stuff Pavel Dovgalyuk
` (11 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
Saving icount as a parameters of the snapshot allows navigation between
them in the execution replay scenario.
This information can be used for finding a specific snapshot for proceeding
the recorded execution to the specific moment of the time.
E.g., 'reverse step' action (introduced in one of the following patches)
needs to load the nearest snapshot which is prior to the current moment
of time.
This patch also updates snapshot test which verifies qemu monitor output.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
--
v4 changes:
- squashed format update with test output update
v7 changes:
- introduced the spaces between the fields in snapshot info output
- updated the test to match new field widths
---
block/qapi.c | 18 +++++++++++++----
block/qcow2-snapshot.c | 2 ++
blockdev.c | 10 +++++++++
include/block/snapshot.h | 1 +
migration/savevm.c | 5 +++++
qapi/block-core.json | 10 +++++++--
stubs/replay.c | 5 +++++
tests/qemu-iotests/261 | 4 ++--
tests/qemu-iotests/267.out | 48 ++++++++++++++++++++++----------------------
9 files changed, 71 insertions(+), 32 deletions(-)
diff --git a/block/qapi.c b/block/qapi.c
index f423ece98c..036da085ee 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -230,6 +230,8 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
info->date_nsec = sn_tab[i].date_nsec;
info->vm_clock_sec = sn_tab[i].vm_clock_nsec / 1000000000;
info->vm_clock_nsec = sn_tab[i].vm_clock_nsec % 1000000000;
+ info->icount = sn_tab[i].icount;
+ info->has_icount = sn_tab[i].icount != -1ULL;
info_list = g_new0(SnapshotInfoList, 1);
info_list->value = info;
@@ -694,14 +696,15 @@ BlockStatsList *qmp_query_blockstats(bool has_query_nodes,
void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
{
char date_buf[128], clock_buf[128];
+ char icount_buf[128] = {0};
struct tm tm;
time_t ti;
int64_t secs;
char *sizing = NULL;
if (!sn) {
- qemu_printf("%-10s%-20s%11s%20s%15s",
- "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK");
+ qemu_printf("%-10s%-18s%7s%20s%13s%11s",
+ "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK", "ICOUNT");
} else {
ti = sn->date_sec;
localtime_r(&ti, &tm);
@@ -715,11 +718,16 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
(int)(secs % 60),
(int)((sn->vm_clock_nsec / 1000000) % 1000));
sizing = size_to_str(sn->vm_state_size);
- qemu_printf("%-10s%-20s%11s%20s%15s",
+ if (sn->icount != -1ULL) {
+ snprintf(icount_buf, sizeof(icount_buf),
+ "%"PRId64, sn->icount);
+ }
+ qemu_printf("%-9s %-17s %7s%20s%13s%11s",
sn->id_str, sn->name,
sizing,
date_buf,
- clock_buf);
+ clock_buf,
+ icount_buf);
}
g_free(sizing);
}
@@ -881,6 +889,8 @@ void bdrv_image_info_dump(ImageInfo *info)
.date_nsec = elem->value->date_nsec,
.vm_clock_nsec = elem->value->vm_clock_sec * 1000000000ULL +
elem->value->vm_clock_nsec,
+ .icount = elem->value->has_icount ?
+ elem->value->icount : -1ULL,
};
pstrcpy(sn.id_str, sizeof(sn.id_str), elem->value->id);
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index d68b25e0c5..2e98c7f4b6 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -663,6 +663,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
sn->date_sec = sn_info->date_sec;
sn->date_nsec = sn_info->date_nsec;
sn->vm_clock_nsec = sn_info->vm_clock_nsec;
+ sn->icount = sn_info->icount;
sn->extra_data_size = sizeof(QCowSnapshotExtraData);
/* Allocate the L1 table of the snapshot and copy the current one there. */
@@ -1007,6 +1008,7 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
sn_info->date_sec = sn->date_sec;
sn_info->date_nsec = sn->date_nsec;
sn_info->vm_clock_nsec = sn->vm_clock_nsec;
+ sn_info->icount = sn->icount;
}
*psn_tab = sn_tab;
return s->nb_snapshots;
diff --git a/blockdev.c b/blockdev.c
index bebd3ba1c3..a6ae475dac 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -59,6 +59,7 @@
#include "sysemu/arch_init.h"
#include "sysemu/qtest.h"
#include "sysemu/runstate.h"
+#include "sysemu/replay.h"
#include "qemu/cutils.h"
#include "qemu/help_option.h"
#include "qemu/main-loop.h"
@@ -1190,6 +1191,10 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
info->vm_state_size = sn.vm_state_size;
info->vm_clock_nsec = sn.vm_clock_nsec % 1000000000;
info->vm_clock_sec = sn.vm_clock_nsec / 1000000000;
+ if (sn.icount != -1ULL) {
+ info->icount = sn.icount;
+ info->has_icount = true;
+ }
return info;
@@ -1350,6 +1355,11 @@ static void internal_snapshot_prepare(BlkActionState *common,
sn->date_sec = tv.tv_sec;
sn->date_nsec = tv.tv_usec * 1000;
sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ if (replay_mode != REPLAY_MODE_NONE) {
+ sn->icount = replay_get_current_icount();
+ } else {
+ sn->icount = -1ULL;
+ }
ret1 = bdrv_snapshot_create(bs, sn);
if (ret1 < 0) {
diff --git a/include/block/snapshot.h b/include/block/snapshot.h
index 2bfcd57578..b0fe42993d 100644
--- a/include/block/snapshot.h
+++ b/include/block/snapshot.h
@@ -42,6 +42,7 @@ typedef struct QEMUSnapshotInfo {
uint32_t date_sec; /* UTC date of the snapshot */
uint32_t date_nsec;
uint64_t vm_clock_nsec; /* VM clock relative to boot */
+ uint64_t icount; /* record/replay step */
} QEMUSnapshotInfo;
int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
diff --git a/migration/savevm.c b/migration/savevm.c
index 34e4b71052..0e8dc78684 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2723,6 +2723,11 @@ int save_snapshot(const char *name, Error **errp)
sn->date_sec = tv.tv_sec;
sn->date_nsec = tv.tv_usec * 1000;
sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ if (replay_mode != REPLAY_MODE_NONE) {
+ sn->icount = replay_get_current_icount();
+ } else {
+ sn->icount = -1ULL;
+ }
if (name) {
ret = bdrv_snapshot_find(bs, old_sn, name);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 86ed72ef9f..015cc0afa4 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -27,13 +27,18 @@
#
# @vm-clock-nsec: fractional part in nano seconds to be used with vm-clock-sec
#
+# @icount: Current instruction count. Appears when execution record/replay
+# is enabled. Used for "time-traveling" to match the moment
+# in the recorded execution with the snapshots. (since 5.2)
+#
# Since: 1.3
#
##
{ 'struct': 'SnapshotInfo',
'data': { 'id': 'str', 'name': 'str', 'vm-state-size': 'int',
'date-sec': 'int', 'date-nsec': 'int',
- 'vm-clock-sec': 'int', 'vm-clock-nsec': 'int' } }
+ 'vm-clock-sec': 'int', 'vm-clock-nsec': 'int',
+ '*icount': 'int' } }
##
# @ImageInfoSpecificQCow2EncryptionBase:
@@ -5529,7 +5534,8 @@
# "date-sec": 1000012,
# "date-nsec": 10,
# "vm-clock-sec": 100,
-# "vm-clock-nsec": 20
+# "vm-clock-nsec": 20,
+# "icount": 220414
# }
# }
#
diff --git a/stubs/replay.c b/stubs/replay.c
index 5974ec1f50..eacb366aa8 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -88,3 +88,8 @@ int replay_read_random(void *buf, size_t len)
{
return 0;
}
+
+uint64_t replay_get_current_icount(void)
+{
+ return 0;
+}
diff --git a/tests/qemu-iotests/261 b/tests/qemu-iotests/261
index 848ffa760d..847b4c6a37 100755
--- a/tests/qemu-iotests/261
+++ b/tests/qemu-iotests/261
@@ -392,7 +392,7 @@ _check_test_img -r all
echo
echo "$((sn_count - 1)) snapshots should remain:"
-echo " qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots"
+echo " qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
echo
@@ -519,7 +519,7 @@ _check_test_img -r all
echo
echo '65536 snapshots should remain:'
-echo " qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots"
+echo " qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
# success, all done
diff --git a/tests/qemu-iotests/267.out b/tests/qemu-iotests/267.out
index 215902b3ad..27471ffae8 100644
--- a/tests/qemu-iotests/267.out
+++ b/tests/qemu-iotests/267.out
@@ -33,8 +33,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -44,8 +44,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -69,8 +69,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -94,8 +94,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -105,8 +105,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -119,8 +119,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -134,8 +134,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
@@ -145,15 +145,15 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
Internal snapshots on overlay:
Snapshot list:
-ID TAG VM SIZE DATE VM CLOCK
-1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
Internal snapshots on backing file:
=== -blockdev with NBD server on the backing file ===
@@ -166,17 +166,17 @@ QEMU X.Y.Z monitor - type 'help' for more information
(qemu) savevm snap0
(qemu) info snapshots
List of snapshots present on all disks:
-ID TAG VM SIZE DATE VM CLOCK
--- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
(qemu) loadvm snap0
(qemu) quit
Internal snapshots on overlay:
Snapshot list:
-ID TAG VM SIZE DATE VM CLOCK
-1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
Internal snapshots on backing file:
Snapshot list:
-ID TAG VM SIZE DATE VM CLOCK
-1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID TAG VM SIZE DATE VM CLOCK ICOUNT
+1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
*** done
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 05/14] qapi: introduce replay.json for record/replay-related stuff
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (3 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 04/14] migration: " Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 06/14] replay: introduce info hmp/qmp command Pavel Dovgalyuk
` (10 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
This patch adds replay.json file. It will be
used for adding record/replay-related data structures and commands.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
MAINTAINERS | 1 +
include/sysemu/replay.h | 1 +
qapi/meson.build | 1 +
qapi/misc.json | 18 ------------------
qapi/qapi-schema.json | 1 +
qapi/replay.json | 26 ++++++++++++++++++++++++++
6 files changed, 30 insertions(+), 18 deletions(-)
create mode 100644 qapi/replay.json
diff --git a/MAINTAINERS b/MAINTAINERS
index b76fb31861..ea4fa3e481 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2693,6 +2693,7 @@ F: include/sysemu/replay.h
F: docs/replay.txt
F: stubs/replay.c
F: tests/acceptance/replay_kernel.py
+F: qapi/replay.json
IOVA Tree
M: Peter Xu <peterx@redhat.com>
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index c9c896ae8d..e00ed2f4a5 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -14,6 +14,7 @@
#include "qapi/qapi-types-misc.h"
#include "qapi/qapi-types-run-state.h"
+#include "qapi/qapi-types-replay.h"
#include "qapi/qapi-types-ui.h"
#include "block/aio.h"
diff --git a/qapi/meson.build b/qapi/meson.build
index 7c4a89a882..8ae085a17d 100644
--- a/qapi/meson.build
+++ b/qapi/meson.build
@@ -38,6 +38,7 @@ qapi_all_modules = [
'pci',
'qom',
'rdma',
+ 'replay',
'rocker',
'run-state',
'sockets',
diff --git a/qapi/misc.json b/qapi/misc.json
index 694d2142f3..7d1e2e9aae 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -757,24 +757,6 @@
'returns': ['CommandLineOptionInfo'],
'allow-preconfig': true }
-##
-# @ReplayMode:
-#
-# Mode of the replay subsystem.
-#
-# @none: normal execution mode. Replay or record are not enabled.
-#
-# @record: record mode. All non-deterministic data is written into the
-# replay log.
-#
-# @play: replay mode. Non-deterministic data required for system execution
-# is read from the log.
-#
-# Since: 2.5
-##
-{ 'enum': 'ReplayMode',
- 'data': [ 'none', 'record', 'play' ] }
-
##
# @xen-load-devices-state:
#
diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json
index 0c6ca5c000..d0ea66ca05 100644
--- a/qapi/qapi-schema.json
+++ b/qapi/qapi-schema.json
@@ -84,6 +84,7 @@
{ 'include': 'qdev.json' }
{ 'include': 'machine.json' }
{ 'include': 'machine-target.json' }
+{ 'include': 'replay.json' }
{ 'include': 'misc.json' }
{ 'include': 'misc-target.json' }
{ 'include': 'audio.json' }
diff --git a/qapi/replay.json b/qapi/replay.json
new file mode 100644
index 0000000000..9e13551d20
--- /dev/null
+++ b/qapi/replay.json
@@ -0,0 +1,26 @@
+# -*- Mode: Python -*-
+#
+
+##
+# = Record/replay
+##
+
+{ 'include': 'common.json' }
+
+##
+# @ReplayMode:
+#
+# Mode of the replay subsystem.
+#
+# @none: normal execution mode. Replay or record are not enabled.
+#
+# @record: record mode. All non-deterministic data is written into the
+# replay log.
+#
+# @play: replay mode. Non-deterministic data required for system execution
+# is read from the log.
+#
+# Since: 2.5
+##
+{ 'enum': 'ReplayMode',
+ 'data': [ 'none', 'record', 'play' ] }
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 06/14] replay: introduce info hmp/qmp command
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (4 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 05/14] qapi: introduce replay.json for record/replay-related stuff Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 07/14] replay: introduce breakpoint at the specified step Pavel Dovgalyuk
` (9 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
This patch introduces 'info replay' monitor command and
corresponding qmp request.
These commands request the current record/replay mode, replay log file
name, and the instruction count (number of recorded/replayed
instructions). The instruction count can be used with the
replay_seek/replay_break commands added in the next two patches.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
---
hmp-commands-info.hx | 11 +++++++++++
include/monitor/hmp.h | 1 +
qapi/block-core.json | 3 ++-
qapi/replay.json | 39 +++++++++++++++++++++++++++++++++++++++
replay/meson.build | 1 +
replay/replay-debugging.c | 43 +++++++++++++++++++++++++++++++++++++++++++
6 files changed, 97 insertions(+), 1 deletion(-)
create mode 100644 replay/replay-debugging.c
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index 30209e3903..117ba25f91 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -881,4 +881,15 @@ SRST
Show SEV information.
ERST
+ {
+ .name = "replay",
+ .args_type = "",
+ .params = "",
+ .help = "show record/replay information",
+ .cmd = hmp_info_replay,
+ },
+SRST
+ ``info replay``
+ Display the record/replay information: mode and the current icount.
+ERST
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 642e9e91f9..f297fccce8 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -129,5 +129,6 @@ void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict);
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);
#endif
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 015cc0afa4..a4c6c59bd8 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -29,7 +29,8 @@
#
# @icount: Current instruction count. Appears when execution record/replay
# is enabled. Used for "time-traveling" to match the moment
-# in the recorded execution with the snapshots. (since 5.2)
+# in the recorded execution with the snapshots. This counter may
+# be obtained through @query-replay command (since 5.2)
#
# Since: 1.3
#
diff --git a/qapi/replay.json b/qapi/replay.json
index 9e13551d20..e6b3f6001d 100644
--- a/qapi/replay.json
+++ b/qapi/replay.json
@@ -24,3 +24,42 @@
##
{ 'enum': 'ReplayMode',
'data': [ 'none', 'record', 'play' ] }
+
+##
+# @ReplayInfo:
+#
+# Record/replay information.
+#
+# @mode: current mode.
+#
+# @filename: name of the record/replay log file.
+# It is present only in record or replay modes, when the log
+# is recorded or replayed.
+#
+# @icount: current number of executed instructions.
+#
+# Since: 5.2
+#
+##
+{ 'struct': 'ReplayInfo',
+ 'data': { 'mode': 'ReplayMode', '*filename': 'str', 'icount': 'int' } }
+
+##
+# @query-replay:
+#
+# Retrieve the record/replay information.
+# It includes current instruction count which may be used for
+# @replay-break and @replay-seek commands.
+#
+# Returns: record/replay information.
+#
+# Since: 5.2
+#
+# Example:
+#
+# -> { "execute": "query-replay" }
+# <- { "return": { "mode": "play", "filename": "log.rr", "icount": 220414 } }
+#
+##
+{ 'command': 'query-replay',
+ 'returns': 'ReplayInfo' }
diff --git a/replay/meson.build b/replay/meson.build
index 8783aea7c8..f91163fb1e 100644
--- a/replay/meson.build
+++ b/replay/meson.build
@@ -9,4 +9,5 @@ softmmu_ss.add(files(
'replay-net.c',
'replay-audio.c',
'replay-random.c',
+ 'replay-debugging.c',
))
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
new file mode 100644
index 0000000000..51a6de4e81
--- /dev/null
+++ b/replay/replay-debugging.c
@@ -0,0 +1,43 @@
+/*
+ * replay-debugging.c
+ *
+ * Copyright (c) 2010-2020 Institute for System Programming
+ * of the Russian Academy of Sciences.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "sysemu/replay.h"
+#include "replay-internal.h"
+#include "monitor/hmp.h"
+#include "monitor/monitor.h"
+#include "qapi/qapi-commands-replay.h"
+
+void hmp_info_replay(Monitor *mon, const QDict *qdict)
+{
+ if (replay_mode == REPLAY_MODE_NONE) {
+ monitor_printf(mon, "Record/replay is not active\n");
+ } else {
+ monitor_printf(mon,
+ "%s execution '%s': instruction count = %"PRId64"\n",
+ replay_mode == REPLAY_MODE_RECORD ? "Recording" : "Replaying",
+ replay_get_filename(), replay_get_current_icount());
+ }
+}
+
+ReplayInfo *qmp_query_replay(Error **errp)
+{
+ ReplayInfo *retval = g_new0(ReplayInfo, 1);
+
+ retval->mode = replay_mode;
+ if (replay_get_filename()) {
+ retval->filename = g_strdup(replay_get_filename());
+ retval->has_filename = true;
+ }
+ retval->icount = replay_get_current_icount();
+ return retval;
+}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 07/14] replay: introduce breakpoint at the specified step
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (5 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 06/14] replay: introduce info hmp/qmp command Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 08/14] replay: implement replay-seek command Pavel Dovgalyuk
` (8 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
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
---
hmp-commands.hx | 32 +++++++++++++++++
include/monitor/hmp.h | 2 +
qapi/replay.json | 36 +++++++++++++++++++
replay/replay-debugging.c | 84 +++++++++++++++++++++++++++++++++++++++++++++
replay/replay-internal.h | 4 ++
replay/replay.c | 17 +++++++++
6 files changed, 175 insertions(+)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 1088d64503..7680d0b380 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1804,6 +1804,38 @@ SRST
Set QOM property *property* of object at location *path* to value *value*
ERST
+ {
+ .name = "replay_break",
+ .args_type = "icount:i",
+ .params = "icount",
+ .help = "set breakpoint at the specified instruction count",
+ .cmd = hmp_replay_break,
+ },
+
+SRST
+``replay_break`` *icount*
+ 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 ``info replay``.
+ERST
+
+ {
+ .name = "replay_delete_break",
+ .args_type = "",
+ .params = "",
+ .help = "remove replay breakpoint",
+ .cmd = hmp_replay_delete_break,
+ },
+
+SRST
+``replay_delete_break``
+ Remove replay breakpoint which was previously set with ``replay_break``.
+ The command is ignored when there are no replay breakpoints.
+ERST
+
{
.name = "info",
.args_type = "item:s?",
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index f297fccce8..809ad638bb 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -130,5 +130,7 @@ 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 e6b3f6001d..173ba76107 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: 5.2
+#
+# 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: 5.2
+#
+# Example:
+#
+# -> { "execute": "replay-delete-break" }
+#
+##
+{ 'command': 'replay-delete-break' }
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 42e82f7bc7..220886e32e 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));
+ }
}
}
}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 08/14] replay: implement replay-seek command
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (6 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 07/14] replay: introduce breakpoint at the specified step Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 09/14] replay: flush rr queue before loading the vmstate Pavel Dovgalyuk
` (7 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
This patch adds hmp/qmp commands replay_seek/replay-seek that proceed
the execution to the specified instruction count.
The command automatically loads nearest snapshot and replays the execution
to find the desired instruction count.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>
--
v4 changes:
- fixed HMP command description indent
- removed useless error_free call
---
hmp-commands.hx | 18 +++++++++
include/monitor/hmp.h | 1 +
qapi/replay.json | 20 ++++++++++
replay/replay-debugging.c | 87 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 126 insertions(+)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 7680d0b380..e43ce600b8 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1836,6 +1836,24 @@ SRST
The command is ignored when there are no replay breakpoints.
ERST
+ {
+ .name = "replay_seek",
+ .args_type = "icount:i",
+ .params = "icount",
+ .help = "replay execution to the specified instruction count",
+ .cmd = hmp_replay_seek,
+ },
+
+SRST
+``replay_seek`` *icount*
+ Automatically proceed to the instruction count *icount*, when
+ replaying the execution. The command automatically loads nearest
+ snapshot and replays the execution to find the desired instruction.
+ When there is no preceding snapshot or the execution is not replayed,
+ then the command fails.
+ *icount* for the reference may be observed with ``info replay`` command.
+ERST
+
{
.name = "info",
.args_type = "item:s?",
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 809ad638bb..ed2913fd18 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -132,5 +132,6 @@ 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);
+void hmp_replay_seek(Monitor *mon, const QDict *qdict);
#endif
diff --git a/qapi/replay.json b/qapi/replay.json
index 173ba76107..bfd83d7591 100644
--- a/qapi/replay.json
+++ b/qapi/replay.json
@@ -99,3 +99,23 @@
#
##
{ 'command': 'replay-delete-break' }
+
+##
+# @replay-seek:
+#
+# Automatically proceed to the instruction count @icount, when
+# replaying the execution. The command automatically loads nearest
+# snapshot and replays the execution to find the desired instruction.
+# When there is no preceding snapshot or the execution is not replayed,
+# then the command fails.
+# icount for the reference may be obtained with @query-replay command.
+#
+# @icount: target instruction count
+#
+# Since: 5.2
+#
+# Example:
+#
+# -> { "execute": "replay-seek", "data": { "icount": 220414 } }
+##
+{ 'command': 'replay-seek', 'data': { 'icount': 'int' } }
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index 3dc23b84fc..e1fe6b8661 100644
--- a/replay/replay-debugging.c
+++ b/replay/replay-debugging.c
@@ -19,6 +19,8 @@
#include "qapi/qapi-commands-replay.h"
#include "qapi/qmp/qdict.h"
#include "qemu/timer.h"
+#include "block/snapshot.h"
+#include "migration/snapshot.h"
void hmp_info_replay(Monitor *mon, const QDict *qdict)
{
@@ -125,3 +127,88 @@ void hmp_replay_delete_break(Monitor *mon, const QDict *qdict)
return;
}
}
+
+static char *replay_find_nearest_snapshot(int64_t icount,
+ int64_t *snapshot_icount)
+{
+ BlockDriverState *bs;
+ QEMUSnapshotInfo *sn_tab;
+ QEMUSnapshotInfo *nearest = NULL;
+ char *ret = NULL;
+ int nb_sns, i;
+ AioContext *aio_context;
+
+ *snapshot_icount = -1;
+
+ bs = bdrv_all_find_vmstate_bs();
+ if (!bs) {
+ goto fail;
+ }
+ aio_context = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(aio_context);
+ nb_sns = bdrv_snapshot_list(bs, &sn_tab);
+ aio_context_release(aio_context);
+
+ for (i = 0; i < nb_sns; i++) {
+ if (bdrv_all_find_snapshot(sn_tab[i].name, &bs) == 0) {
+ if (sn_tab[i].icount != -1ULL
+ && sn_tab[i].icount <= icount
+ && (!nearest || nearest->icount < sn_tab[i].icount)) {
+ nearest = &sn_tab[i];
+ }
+ }
+ }
+ if (nearest) {
+ ret = g_strdup(nearest->name);
+ *snapshot_icount = nearest->icount;
+ }
+ g_free(sn_tab);
+
+fail:
+ return ret;
+}
+
+static void replay_seek(int64_t icount, QEMUTimerCB callback, Error **errp)
+{
+ char *snapshot = NULL;
+ int64_t snapshot_icount;
+
+ if (replay_mode != REPLAY_MODE_PLAY) {
+ error_setg(errp, "replay must be enabled to seek");
+ return;
+ }
+
+ snapshot = replay_find_nearest_snapshot(icount, &snapshot_icount);
+ if (snapshot) {
+ if (icount < replay_get_current_icount()
+ || replay_get_current_icount() < snapshot_icount) {
+ vm_stop(RUN_STATE_RESTORE_VM);
+ load_snapshot(snapshot, errp);
+ }
+ g_free(snapshot);
+ }
+ if (replay_get_current_icount() <= icount) {
+ replay_break(icount, callback, NULL);
+ vm_start();
+ } else {
+ error_setg(errp, "cannot seek to the specified instruction count");
+ }
+}
+
+void qmp_replay_seek(int64_t icount, Error **errp)
+{
+ replay_seek(icount, replay_stop_vm, errp);
+}
+
+void hmp_replay_seek(Monitor *mon, const QDict *qdict)
+{
+ int64_t icount = qdict_get_try_int(qdict, "icount", -1LL);
+ Error *err = NULL;
+
+ qmp_replay_seek(icount, &err);
+ if (err) {
+ error_report_err(err);
+ return;
+ }
+}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 09/14] replay: flush rr queue before loading the vmstate
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (7 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 08/14] replay: implement replay-seek command Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 10/14] gdbstub: add reverse step support in replay mode Pavel Dovgalyuk
` (6 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Non-empty record/replay queue prevents saving and loading the VM state,
because it includes pending bottom halves and block coroutines.
But when the new VM state is loaded, we don't have to preserve the consistency
of the current state anymore. Therefore this patch just flushes the queue
allowing the coroutines to finish and removes checking for empty rr queue
for load_snapshot function.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
include/sysemu/replay.h | 2 ++
migration/savevm.c | 12 ++++++------
replay/replay-events.c | 4 ++++
replay/replay-internal.h | 2 --
4 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index e00ed2f4a5..239c01e7df 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -149,6 +149,8 @@ void replay_disable_events(void);
void replay_enable_events(void);
/*! Returns true when saving events is enabled */
bool replay_events_enabled(void);
+/* Flushes events queue */
+void replay_flush_events(void);
/*! Adds bottom half event to the queue */
void replay_bh_schedule_event(QEMUBH *bh);
/* Adds oneshot bottom half event to the queue */
diff --git a/migration/savevm.c b/migration/savevm.c
index 0e8dc78684..d2e141f7b1 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2881,12 +2881,6 @@ int load_snapshot(const char *name, Error **errp)
AioContext *aio_context;
MigrationIncomingState *mis = migration_incoming_get_current();
- if (!replay_can_snapshot()) {
- error_setg(errp, "Record/replay does not allow loading snapshot "
- "right now. Try once more later.");
- return -EINVAL;
- }
-
if (!bdrv_all_can_snapshot(&bs)) {
error_setg(errp,
"Device '%s' is writable but does not support snapshots",
@@ -2920,6 +2914,12 @@ int load_snapshot(const char *name, Error **errp)
return -EINVAL;
}
+ /*
+ * Flush the record/replay queue. Now the VM state is going
+ * to change. Therefore we don't need to preserve its consistency
+ */
+ replay_flush_events();
+
/* Flush all IO requests so they don't interfere with the new state. */
bdrv_drain_all_begin();
diff --git a/replay/replay-events.c b/replay/replay-events.c
index 302b84043a..a1c6bb934e 100644
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -77,6 +77,10 @@ bool replay_has_events(void)
void replay_flush_events(void)
{
+ if (replay_mode == REPLAY_MODE_NONE) {
+ return;
+ }
+
g_assert(replay_mutex_locked());
while (!QTAILQ_EMPTY(&events_list)) {
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 2f6145ec7c..97649ed8d7 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -149,8 +149,6 @@ void replay_read_next_clock(unsigned int kind);
void replay_init_events(void);
/*! Clears internal data structures for events handling */
void replay_finish_events(void);
-/*! Flushes events queue */
-void replay_flush_events(void);
/*! Returns true if there are any unsaved events in the queue */
bool replay_has_events(void);
/*! Saves events from queue into the file */
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 10/14] gdbstub: add reverse step support in replay mode
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (8 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 09/14] replay: flush rr queue before loading the vmstate Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 11/14] gdbstub: add reverse continue " Pavel Dovgalyuk
` (5 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
GDB remote protocol supports two reverse debugging commands:
reverse step and reverse continue.
This patch adds support of the first one to the gdbstub.
Reverse step is intended to step one instruction in the backwards
direction. This is not possible in regular execution.
But replayed execution is deterministic, therefore we can load one of
the prior snapshots and proceed to the desired step. It is equivalent
to stepping one instruction back.
There should be at least one snapshot preceding the debugged part of
the replay log.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
--
v4 changes:
- inverted condition in cpu_handle_guest_debug (suggested by Alex Bennée)
---
accel/tcg/translator.c | 1 +
exec.c | 7 ++++++
gdbstub.c | 55 +++++++++++++++++++++++++++++++++++++++++++--
include/sysemu/replay.h | 11 +++++++++
replay/replay-debugging.c | 34 ++++++++++++++++++++++++++++
softmmu/cpus.c | 14 +++++++++--
stubs/replay.c | 5 ++++
7 files changed, 122 insertions(+), 5 deletions(-)
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 603d17ff83..fb1e19c585 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -17,6 +17,7 @@
#include "exec/log.h"
#include "exec/translator.h"
#include "exec/plugin-gen.h"
+#include "sysemu/replay.h"
/* Pairs with tcg_clear_temp_count.
To be called by #TranslatorOps.{translate_insn,tb_stop} if
diff --git a/exec.c b/exec.c
index c088559d94..80db218c99 100644
--- a/exec.c
+++ b/exec.c
@@ -2752,6 +2752,13 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
if (watchpoint_address_matches(wp, addr, len)
&& (wp->flags & flags)) {
+ if (replay_running_debug()) {
+ /*
+ * Don't process the watchpoints when we are
+ * in a reverse debugging operation.
+ */
+ return;
+ }
if (flags == BP_MEM_READ) {
wp->flags |= BP_WATCHPOINT_HIT_READ;
} else {
diff --git a/gdbstub.c b/gdbstub.c
index 9dfb6e4142..79e8ccc050 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -51,6 +51,7 @@
#include "sysemu/runstate.h"
#include "hw/semihosting/semihost.h"
#include "exec/exec-all.h"
+#include "sysemu/replay.h"
#ifdef CONFIG_USER_ONLY
#define GDB_ATTACHED "0"
@@ -375,6 +376,20 @@ typedef struct GDBState {
*/
static int sstep_flags = SSTEP_ENABLE|SSTEP_NOIRQ|SSTEP_NOTIMER;
+/* Retrieves flags for single step mode. */
+static int get_sstep_flags(void)
+{
+ /*
+ * In replay mode all events written into the log should be replayed.
+ * That is why NOIRQ flag is removed in this mode.
+ */
+ if (replay_mode != REPLAY_MODE_NONE) {
+ return SSTEP_ENABLE;
+ } else {
+ return sstep_flags;
+ }
+}
+
static GDBState gdbserver_state;
static void init_gdbserver_state(void)
@@ -501,7 +516,7 @@ static int gdb_continue_partial(char *newstates)
break; /* nothing to do here */
case 's':
trace_gdbstub_op_stepping(cpu->cpu_index);
- cpu_single_step(cpu, sstep_flags);
+ cpu_single_step(cpu, get_sstep_flags());
cpu_resume(cpu);
flag = 1;
break;
@@ -1874,10 +1889,31 @@ static void handle_step(GdbCmdContext *gdb_ctx, void *user_ctx)
gdb_set_cpu_pc((target_ulong)gdb_ctx->params[0].val_ull);
}
- cpu_single_step(gdbserver_state.c_cpu, sstep_flags);
+ cpu_single_step(gdbserver_state.c_cpu, get_sstep_flags());
gdb_continue();
}
+static void handle_backward(GdbCmdContext *gdb_ctx, void *user_ctx)
+{
+ if (replay_mode != REPLAY_MODE_PLAY) {
+ put_packet("E22");
+ }
+ if (gdb_ctx->num_params == 1) {
+ switch (gdb_ctx->params[0].opcode) {
+ case 's':
+ if (replay_reverse_step()) {
+ gdb_continue();
+ } else {
+ put_packet("E14");
+ }
+ return;
+ }
+ }
+
+ /* Default invalid command */
+ put_packet("");
+}
+
static void handle_v_cont_query(GdbCmdContext *gdb_ctx, void *user_ctx)
{
put_packet("vCont;c;C;s;S");
@@ -2124,6 +2160,10 @@ static void handle_query_supported(GdbCmdContext *gdb_ctx, void *user_ctx)
g_string_append(gdbserver_state.str_buf, ";qXfer:features:read+");
}
+ if (replay_mode == REPLAY_MODE_PLAY) {
+ g_string_append(gdbserver_state.str_buf, ";ReverseStep+");
+ }
+
if (gdb_ctx->num_params &&
strstr(gdb_ctx->params[0].data, "multiprocess+")) {
gdbserver_state.multiprocess = true;
@@ -2460,6 +2500,17 @@ static int gdb_handle_packet(const char *line_buf)
cmd_parser = &step_cmd_desc;
}
break;
+ case 'b':
+ {
+ static const GdbCmdParseEntry backward_cmd_desc = {
+ .handler = handle_backward,
+ .cmd = "b",
+ .cmd_startswith = 1,
+ .schema = "o0"
+ };
+ cmd_parser = &backward_cmd_desc;
+ }
+ break;
case 'F':
{
static const GdbCmdParseEntry file_io_cmd_desc = {
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index 239c01e7df..13a8123b09 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -75,6 +75,17 @@ void replay_finish(void);
void replay_add_blocker(Error *reason);
/* Returns name of the replay log file */
const char *replay_get_filename(void);
+/*
+ * Start making one step in backward direction.
+ * Used by gdbstub for backwards debugging.
+ * Returns true on success.
+ */
+bool replay_reverse_step(void);
+/*
+ * Returns true if replay module is processing
+ * reverse_continue or reverse_step request
+ */
+bool replay_running_debug(void);
/* Processing the instructions */
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index e1fe6b8661..1e1dec0295 100644
--- a/replay/replay-debugging.c
+++ b/replay/replay-debugging.c
@@ -22,6 +22,13 @@
#include "block/snapshot.h"
#include "migration/snapshot.h"
+static bool replay_is_debugging;
+
+bool replay_running_debug(void)
+{
+ return replay_is_debugging;
+}
+
void hmp_info_replay(Monitor *mon, const QDict *qdict)
{
if (replay_mode == REPLAY_MODE_NONE) {
@@ -212,3 +219,30 @@ void hmp_replay_seek(Monitor *mon, const QDict *qdict)
return;
}
}
+
+static void replay_stop_vm_debug(void *opaque)
+{
+ replay_is_debugging = false;
+ vm_stop(RUN_STATE_DEBUG);
+ replay_delete_break();
+}
+
+bool replay_reverse_step(void)
+{
+ Error *err = NULL;
+
+ assert(replay_mode == REPLAY_MODE_PLAY);
+
+ if (replay_get_current_icount() != 0) {
+ replay_seek(replay_get_current_icount() - 1,
+ replay_stop_vm_debug, &err);
+ if (err) {
+ error_free(err);
+ return false;
+ }
+ replay_is_debugging = true;
+ return true;
+ }
+
+ return false;
+}
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index ac8940d52e..1fa9c4c1de 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -1004,9 +1004,17 @@ static bool cpu_can_run(CPUState *cpu)
static void cpu_handle_guest_debug(CPUState *cpu)
{
- gdb_set_stop_cpu(cpu);
- qemu_system_debug_request();
- cpu->stopped = true;
+ if (replay_running_debug()) {
+ if (!cpu->singlestep_enabled) {
+ cpu_single_step(cpu, SSTEP_ENABLE);
+ } else {
+ cpu_single_step(cpu, 0);
+ }
+ } else {
+ gdb_set_stop_cpu(cpu);
+ qemu_system_debug_request();
+ cpu->stopped = true;
+ }
}
#ifdef CONFIG_LINUX
diff --git a/stubs/replay.c b/stubs/replay.c
index eacb366aa8..d5b52302e9 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -93,3 +93,8 @@ uint64_t replay_get_current_icount(void)
{
return 0;
}
+
+bool replay_reverse_step(void)
+{
+ return false;
+}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 11/14] gdbstub: add reverse continue support in replay mode
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (9 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 10/14] gdbstub: add reverse step support in replay mode Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:13 ` [PATCH v7 12/14] replay: describe reverse debugging in docs/replay.txt Pavel Dovgalyuk
` (4 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
This patch adds support of the reverse continue operation for gdbstub.
Reverse continue finds the last breakpoint that would happen in normal
execution from the beginning to the current moment.
Implementation of the reverse continue replays the execution twice:
to find the breakpoints that were hit and to seek to the last breakpoint.
Reverse continue loads the previous snapshot and tries to find the breakpoint
since that moment. If there are no such breakpoints, it proceeds to
the earlier snapshot, and so on. When no breakpoints or watchpoints were
hit at all, execution stops at the beginning of the replay log.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
---
exec.c | 1 +
gdbstub.c | 10 ++++++
include/sysemu/replay.h | 8 +++++
replay/replay-debugging.c | 72 +++++++++++++++++++++++++++++++++++++++++++++
softmmu/cpus.c | 5 +++
stubs/replay.c | 5 +++
6 files changed, 100 insertions(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index 80db218c99..f4a6d4cf62 100644
--- a/exec.c
+++ b/exec.c
@@ -2757,6 +2757,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
* Don't process the watchpoints when we are
* in a reverse debugging operation.
*/
+ replay_breakpoint();
return;
}
if (flags == BP_MEM_READ) {
diff --git a/gdbstub.c b/gdbstub.c
index 79e8ccc050..ac92273018 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1907,6 +1907,13 @@ static void handle_backward(GdbCmdContext *gdb_ctx, void *user_ctx)
put_packet("E14");
}
return;
+ case 'c':
+ if (replay_reverse_continue()) {
+ gdb_continue();
+ } else {
+ put_packet("E14");
+ }
+ return;
}
}
@@ -2161,7 +2168,8 @@ static void handle_query_supported(GdbCmdContext *gdb_ctx, void *user_ctx)
}
if (replay_mode == REPLAY_MODE_PLAY) {
- g_string_append(gdbserver_state.str_buf, ";ReverseStep+");
+ g_string_append(gdbserver_state.str_buf,
+ ";ReverseStep+;ReverseContinue+");
}
if (gdb_ctx->num_params &&
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index 13a8123b09..b6cac175c4 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -81,11 +81,19 @@ const char *replay_get_filename(void);
* Returns true on success.
*/
bool replay_reverse_step(void);
+/*
+ * Start searching the last breakpoint/watchpoint.
+ * Used by gdbstub for backwards debugging.
+ * Returns true if the process successfully started.
+ */
+bool replay_reverse_continue(void);
/*
* Returns true if replay module is processing
* reverse_continue or reverse_step request
*/
bool replay_running_debug(void);
+/* Called in reverse debugging mode to collect breakpoint information */
+void replay_breakpoint(void);
/* Processing the instructions */
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index 1e1dec0295..30ca38e5dd 100644
--- a/replay/replay-debugging.c
+++ b/replay/replay-debugging.c
@@ -23,6 +23,8 @@
#include "migration/snapshot.h"
static bool replay_is_debugging;
+static int64_t replay_last_breakpoint;
+static int64_t replay_last_snapshot;
bool replay_running_debug(void)
{
@@ -246,3 +248,73 @@ bool replay_reverse_step(void)
return false;
}
+
+static void replay_continue_end(void)
+{
+ replay_is_debugging = false;
+ vm_stop(RUN_STATE_DEBUG);
+ replay_delete_break();
+}
+
+static void replay_continue_stop(void *opaque)
+{
+ Error *err = NULL;
+ if (replay_last_breakpoint != -1LL) {
+ replay_seek(replay_last_breakpoint, replay_stop_vm_debug, &err);
+ if (err) {
+ error_free(err);
+ replay_continue_end();
+ }
+ return;
+ }
+ /*
+ * No breakpoints since the last snapshot.
+ * Find previous snapshot and try again.
+ */
+ if (replay_last_snapshot != 0) {
+ replay_seek(replay_last_snapshot - 1, replay_continue_stop, &err);
+ if (err) {
+ error_free(err);
+ replay_continue_end();
+ }
+ replay_last_snapshot = replay_get_current_icount();
+ return;
+ } else {
+ /* Seek to the very first step */
+ replay_seek(0, replay_stop_vm_debug, &err);
+ if (err) {
+ error_free(err);
+ replay_continue_end();
+ }
+ return;
+ }
+ replay_continue_end();
+}
+
+bool replay_reverse_continue(void)
+{
+ Error *err = NULL;
+
+ assert(replay_mode == REPLAY_MODE_PLAY);
+
+ if (replay_get_current_icount() != 0) {
+ replay_seek(replay_get_current_icount() - 1,
+ replay_continue_stop, &err);
+ if (err) {
+ error_free(err);
+ return false;
+ }
+ replay_last_breakpoint = -1LL;
+ replay_is_debugging = true;
+ replay_last_snapshot = replay_get_current_icount();
+ return true;
+ }
+
+ return false;
+}
+
+void replay_breakpoint(void)
+{
+ assert(replay_mode == REPLAY_MODE_PLAY);
+ replay_last_breakpoint = replay_get_current_icount();
+}
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index 1fa9c4c1de..8334dceab4 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -1006,6 +1006,11 @@ static void cpu_handle_guest_debug(CPUState *cpu)
{
if (replay_running_debug()) {
if (!cpu->singlestep_enabled) {
+ /*
+ * Report about the breakpoint and
+ * make a single step to skip it
+ */
+ replay_breakpoint();
cpu_single_step(cpu, SSTEP_ENABLE);
} else {
cpu_single_step(cpu, 0);
diff --git a/stubs/replay.c b/stubs/replay.c
index d5b52302e9..45ebe77fb9 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -98,3 +98,8 @@ bool replay_reverse_step(void)
{
return false;
}
+
+bool replay_reverse_continue(void)
+{
+ return false;
+}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 12/14] replay: describe reverse debugging in docs/replay.txt
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (10 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 11/14] gdbstub: add reverse continue " Pavel Dovgalyuk
@ 2020-10-03 17:13 ` Pavel Dovgalyuk
2020-10-03 17:14 ` [PATCH v7 13/14] replay: create temporary snapshot at debugger connection Pavel Dovgalyuk
` (3 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:13 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
This patch updates the documentation and describes usage of the reverse
debugging in QEMU+GDB.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
--
v4 changes:
- added an example of the command line for reverse debugging of
the diskless machine
---
docs/replay.txt | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/docs/replay.txt b/docs/replay.txt
index 70c27edb36..39fe5e9740 100644
--- a/docs/replay.txt
+++ b/docs/replay.txt
@@ -265,6 +265,16 @@ of the original disk image, use overlay files linked to the original images.
Therefore all new snapshots (including the starting one) will be saved in
overlays and the original image remains unchanged.
+When you need to use snapshots with diskless virtual machine,
+it must be started with 'orphan' qcow2 image. This image will be used
+for storing VM snapshots. Here is the example of the command line for this:
+
+ qemu-system-i386 -icount shift=3,rr=replay,rrfile=record.bin,rrsnapshot=init \
+ -net none -drive file=empty.qcow2,if=none,id=rr
+
+empty.qcow2 drive does not connected to any virtual block device and used
+for VM snapshots only.
+
Network devices
---------------
@@ -294,6 +304,42 @@ for recording and replaying must contain identical number of ports in record
and replay modes, but their backends may differ.
E.g., '-serial stdio' in record mode, and '-serial null' in replay mode.
+Reverse debugging
+-----------------
+
+Reverse debugging allows "executing" the program in reverse direction.
+GDB remote protocol supports "reverse step" and "reverse continue"
+commands. The first one steps single instruction backwards in time,
+and the second one finds the last breakpoint in the past.
+
+Recorded executions may be used to enable reverse debugging. QEMU can't
+execute the code in backwards direction, but can load a snapshot and
+replay forward to find the desired position or breakpoint.
+
+The following GDB commands are supported:
+ - reverse-stepi (or rsi) - step one instruction backwards
+ - reverse-continue (or rc) - find last breakpoint in the past
+
+Reverse step loads the nearest snapshot and replays the execution until
+the required instruction is met.
+
+Reverse continue may include several passes of examining the execution
+between the snapshots. Each of the passes include the following steps:
+ 1. loading the snapshot
+ 2. replaying to examine the breakpoints
+ 3. if breakpoint or watchpoint was met
+ - loading the snaphot again
+ - replaying to the required breakpoint
+ 4. else
+ - proceeding to the p.1 with the earlier snapshot
+
+Therefore usage of the reverse debugging requires at least one snapshot
+created in advance. This can be done by omitting 'snapshot' option
+for the block drives and adding 'rrsnapshot' for both record and replay
+command lines.
+See the "Snapshotting" section to learn more about running record/replay
+and creating the snapshot in these modes.
+
Replay log format
-----------------
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 13/14] replay: create temporary snapshot at debugger connection
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (11 preceding siblings ...)
2020-10-03 17:13 ` [PATCH v7 12/14] replay: describe reverse debugging in docs/replay.txt Pavel Dovgalyuk
@ 2020-10-03 17:14 ` Pavel Dovgalyuk
2020-10-03 17:14 ` [PATCH v7 14/14] tests/acceptance: add reverse debugging test Pavel Dovgalyuk
` (2 subsequent siblings)
15 siblings, 0 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:14 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
When record/replay does not uses overlays for storing the snapshots,
user is not capable of issuing reverse debugging commands.
This patch adds creation of the VM snapshot on the temporary
overlay image, when the debugger connects to QEMU.
Therefore the execution can be rewind to the moment
of the debugger connection while debugging the virtual machine.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
--
v6:
- dropped unused error processing (suggested by Philippe Mathieu-Daudé)
---
gdbstub.c | 1 +
include/sysemu/replay.h | 2 ++
replay/replay-debugging.c | 14 ++++++++++++++
3 files changed, 17 insertions(+)
diff --git a/gdbstub.c b/gdbstub.c
index ac92273018..f19f98ab1a 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -3321,6 +3321,7 @@ static void gdb_chr_event(void *opaque, QEMUChrEvent event)
s->g_cpu = s->c_cpu;
vm_stop(RUN_STATE_PAUSED);
+ replay_gdb_attached();
gdb_has_xml = false;
break;
default:
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index b6cac175c4..2aa34b8919 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -94,6 +94,8 @@ bool replay_reverse_continue(void);
bool replay_running_debug(void);
/* Called in reverse debugging mode to collect breakpoint information */
void replay_breakpoint(void);
+/* Called when gdb is attached to gdbstub */
+void replay_gdb_attached(void);
/* Processing the instructions */
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index 30ca38e5dd..ee9e86daa9 100644
--- a/replay/replay-debugging.c
+++ b/replay/replay-debugging.c
@@ -318,3 +318,17 @@ void replay_breakpoint(void)
assert(replay_mode == REPLAY_MODE_PLAY);
replay_last_breakpoint = replay_get_current_icount();
}
+
+void replay_gdb_attached(void)
+{
+ /*
+ * Create VM snapshot on temporary overlay to allow reverse
+ * debugging even if snapshots were not enabled.
+ */
+ if (replay_mode == REPLAY_MODE_PLAY
+ && !replay_snapshot) {
+ if (save_snapshot("start_debugging", NULL) != 0) {
+ /* Can't create the snapshot. Continue conventional debugging. */
+ }
+ }
+}
^ permalink raw reply related [flat|nested] 24+ messages in thread* [PATCH v7 14/14] tests/acceptance: add reverse debugging test
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (12 preceding siblings ...)
2020-10-03 17:14 ` [PATCH v7 13/14] replay: create temporary snapshot at debugger connection Pavel Dovgalyuk
@ 2020-10-03 17:14 ` Pavel Dovgalyuk
2020-10-06 13:36 ` Cleber Rosa
2020-10-06 19:55 ` Philippe Mathieu-Daudé
2020-10-04 1:06 ` [PATCH v7 00/14] Reverse debugging no-reply
2020-10-05 12:27 ` Paolo Bonzini
15 siblings, 2 replies; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-03 17:14 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, wrampazz, pavel.dovgalyuk, ehabkost, alex.bennee,
mtosatti, armbru, mreitz, stefanha, crosa, pbonzini, philmd,
zhiwei_liu, rth
From: Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>
This is a test for GDB reverse debugging commands: reverse step and reverse continue.
Every test in this suite consists of two phases: record and replay.
Recording saves the execution of some instructions and makes an initial
VM snapshot to allow reverse execution.
Replay saves the order of the first instructions and then checks that they
are executed backwards in the correct order.
After that the execution is replayed to the end, and reverse continue
command is checked by setting several breakpoints, and asserting
that the execution is stopped at the last of them.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
--
v5:
- disabled (as some other tests) when running on gitlab
due to the unidentified timeout problem
---
MAINTAINERS | 1
tests/acceptance/reverse_debugging.py | 208 +++++++++++++++++++++++++++++++++
2 files changed, 209 insertions(+)
create mode 100644 tests/acceptance/reverse_debugging.py
diff --git a/MAINTAINERS b/MAINTAINERS
index ea4fa3e481..bd3a7efb75 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2693,6 +2693,7 @@ F: include/sysemu/replay.h
F: docs/replay.txt
F: stubs/replay.c
F: tests/acceptance/replay_kernel.py
+F: tests/acceptance/reverse_debugging.py
F: qapi/replay.json
IOVA Tree
diff --git a/tests/acceptance/reverse_debugging.py b/tests/acceptance/reverse_debugging.py
new file mode 100644
index 0000000000..b72fdf6cdc
--- /dev/null
+++ b/tests/acceptance/reverse_debugging.py
@@ -0,0 +1,208 @@
+# Reverse debugging test
+#
+# Copyright (c) 2020 ISP RAS
+#
+# Author:
+# Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later. See the COPYING file in the top-level directory.
+import os
+import logging
+
+from avocado import skipIf
+from avocado_qemu import BUILD_DIR
+from avocado.utils import gdb
+from avocado.utils import process
+from avocado.utils.path import find_command
+from boot_linux_console import LinuxKernelTest
+
+class ReverseDebugging(LinuxKernelTest):
+ """
+ Test GDB reverse debugging commands: reverse step and reverse continue.
+ Recording saves the execution of some instructions and makes an initial
+ VM snapshot to allow reverse execution.
+ Replay saves the order of the first instructions and then checks that they
+ are executed backwards in the correct order.
+ After that the execution is replayed to the end, and reverse continue
+ command is checked by setting several breakpoints, and asserting
+ that the execution is stopped at the last of them.
+ """
+
+ timeout = 10
+ STEPS = 10
+ endian_is_le = True
+
+ def run_vm(self, record, shift, args, replay_path, image_path):
+ logger = logging.getLogger('replay')
+ vm = self.get_vm()
+ vm.set_console()
+ if record:
+ logger.info('recording the execution...')
+ mode = 'record'
+ else:
+ logger.info('replaying the execution...')
+ mode = 'replay'
+ vm.add_args('-s', '-S')
+ vm.add_args('-icount', 'shift=%s,rr=%s,rrfile=%s,rrsnapshot=init' %
+ (shift, mode, replay_path),
+ '-net', 'none')
+ vm.add_args('-drive', 'file=%s,if=none' % image_path)
+ if args:
+ vm.add_args(*args)
+ vm.launch()
+ return vm
+
+ @staticmethod
+ def get_reg_le(g, reg):
+ res = g.cmd(b'p%x' % reg)
+ num = 0
+ for i in range(len(res))[-2::-2]:
+ num = 0x100 * num + int(res[i:i + 2], 16)
+ return num
+
+ @staticmethod
+ def get_reg_be(g, reg):
+ res = g.cmd(b'p%x' % reg)
+ return int(res, 16)
+
+ def get_reg(self, g, reg):
+ # value may be encoded in BE or LE order
+ if self.endian_is_le:
+ return self.get_reg_le(g, reg)
+ else:
+ return self.get_reg_be(g, reg)
+
+ def get_pc(self, g):
+ return self.get_reg(g, self.REG_PC)
+
+ def check_pc(self, g, addr):
+ pc = self.get_pc(g)
+ if pc != addr:
+ self.fail('Invalid PC (read %x instead of %x)' % (pc, addr))
+
+ @staticmethod
+ def gdb_step(g):
+ g.cmd(b's', b'T05thread:01;')
+
+ @staticmethod
+ def gdb_bstep(g):
+ g.cmd(b'bs', b'T05thread:01;')
+
+ @staticmethod
+ def vm_get_icount(vm):
+ return vm.qmp('query-replay')['return']['icount']
+
+ def reverse_debugging(self, shift=7, args=None):
+ logger = logging.getLogger('replay')
+
+ # create qcow2 for snapshots
+ logger.info('creating qcow2 image for VM snapshots')
+ image_path = os.path.join(self.workdir, 'disk.qcow2')
+ qemu_img = os.path.join(BUILD_DIR, 'qemu-img')
+ if not os.path.exists(qemu_img):
+ qemu_img = find_command('qemu-img', False)
+ if qemu_img is False:
+ self.cancel('Could not find "qemu-img", which is required to '
+ 'create the temporary qcow2 image')
+ cmd = '%s create -f qcow2 %s 128M' % (qemu_img, image_path)
+ process.run(cmd)
+
+ replay_path = os.path.join(self.workdir, 'replay.bin')
+
+ # record the log
+ vm = self.run_vm(True, shift, args, replay_path, image_path)
+ while self.vm_get_icount(vm) <= self.STEPS:
+ pass
+ last_icount = self.vm_get_icount(vm)
+ vm.shutdown()
+
+ logger.info("recorded log with %s+ steps" % last_icount)
+
+ # replay and run debug commands
+ vm = self.run_vm(False, shift, args, replay_path, image_path)
+ logger.info('connecting to gdbstub')
+ g = gdb.GDBRemote('127.0.0.1', 1234, False, False)
+ g.connect()
+ r = g.cmd(b'qSupported')
+ if b'qXfer:features:read+' in r:
+ g.cmd(b'qXfer:features:read:target.xml:0,ffb')
+ if b'ReverseStep+' not in r:
+ self.fail('Reverse step is not supported by QEMU')
+ if b'ReverseContinue+' not in r:
+ self.fail('Reverse continue is not supported by QEMU')
+
+ logger.info('stepping forward')
+ steps = []
+ # record first instruction addresses
+ for _ in range(self.STEPS):
+ pc = self.get_pc(g)
+ logger.info('saving position %x' % pc)
+ steps.append(pc)
+ self.gdb_step(g)
+
+ # visit the recorded instruction in reverse order
+ logger.info('stepping backward')
+ for addr in steps[::-1]:
+ self.gdb_bstep(g)
+ self.check_pc(g, addr)
+ logger.info('found position %x' % addr)
+
+ logger.info('seeking to the end (icount %s)' % (last_icount - 1))
+ vm.qmp('replay-break', icount=last_icount - 1)
+ # continue - will return after pausing
+ g.cmd(b'c', b'T02thread:01;')
+
+ logger.info('setting breakpoints')
+ for addr in steps:
+ # hardware breakpoint at addr with len=1
+ g.cmd(b'Z1,%x,1' % addr, b'OK')
+
+ logger.info('running reverse continue to reach %x' % steps[-1])
+ # reverse continue - will return after stopping at the breakpoint
+ g.cmd(b'bc', b'T05thread:01;')
+
+ # assume that none of the first instructions is executed again
+ # breaking the order of the breakpoints
+ self.check_pc(g, steps[-1])
+ logger.info('successfully reached %x' % steps[-1])
+
+ logger.info('exitting gdb and qemu')
+ vm.shutdown()
+
+class ReverseDebugging_X86_64(ReverseDebugging):
+ REG_PC = 0x10
+ REG_CS = 0x12
+ def get_pc(self, g):
+ return self.get_reg_le(g, self.REG_PC) \
+ + self.get_reg_le(g, self.REG_CS) * 0x10
+
+ # unidentified gitlab timeout problem
+ @skipIf(os.getenv('GITLAB_CI'), 'Running on GitLab')
+ def test_x86_64_pc(self):
+ """
+ :avocado: tags=arch:x86_64
+ :avocado: tags=machine:pc
+ """
+ # start with BIOS only
+ self.reverse_debugging()
+
+class ReverseDebugging_AArch64(ReverseDebugging):
+ REG_PC = 32
+
+ # unidentified gitlab timeout problem
+ @skipIf(os.getenv('GITLAB_CI'), 'Running on GitLab')
+ def test_aarch64_virt(self):
+ """
+ :avocado: tags=arch:aarch64
+ :avocado: tags=machine:virt
+ :avocado: tags=cpu:cortex-a53
+ """
+ kernel_url = ('https://archives.fedoraproject.org/pub/archive/fedora'
+ '/linux/releases/29/Everything/aarch64/os/images/pxeboot'
+ '/vmlinuz')
+ kernel_hash = '8c73e469fc6ea06a58dc83a628fc695b693b8493'
+ kernel_path = self.fetch_asset(kernel_url, asset_hash=kernel_hash)
+
+ self.reverse_debugging(
+ args=('-kernel', kernel_path, '-cpu', 'cortex-a53'))
^ permalink raw reply related [flat|nested] 24+ messages in thread* Re: [PATCH v7 14/14] tests/acceptance: add reverse debugging test
2020-10-03 17:14 ` [PATCH v7 14/14] tests/acceptance: add reverse debugging test Pavel Dovgalyuk
@ 2020-10-06 13:36 ` Cleber Rosa
2020-10-06 15:09 ` Pavel Dovgalyuk
2020-10-06 19:55 ` Philippe Mathieu-Daudé
1 sibling, 1 reply; 24+ messages in thread
From: Cleber Rosa @ 2020-10-06 13:36 UTC (permalink / raw)
To: Pavel Dovgalyuk
Cc: kwolf, wrampazz, ehabkost, alex.bennee, mtosatti, qemu-devel,
armbru, stefanha, pbonzini, mreitz, philmd, zhiwei_liu, rth
[-- Attachment #1: Type: text/plain, Size: 9467 bytes --]
On Sat, Oct 03, 2020 at 08:14:06PM +0300, Pavel Dovgalyuk wrote:
> From: Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>
>
> This is a test for GDB reverse debugging commands: reverse step and reverse continue.
> Every test in this suite consists of two phases: record and replay.
> Recording saves the execution of some instructions and makes an initial
> VM snapshot to allow reverse execution.
> Replay saves the order of the first instructions and then checks that they
> are executed backwards in the correct order.
> After that the execution is replayed to the end, and reverse continue
> command is checked by setting several breakpoints, and asserting
> that the execution is stopped at the last of them.
>
> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Reviewed-by: Willian Rampazzo <willianr@redhat.com>
>
> --
>
> v5:
> - disabled (as some other tests) when running on gitlab
> due to the unidentified timeout problem
> ---
> MAINTAINERS | 1
> tests/acceptance/reverse_debugging.py | 208 +++++++++++++++++++++++++++++++++
> 2 files changed, 209 insertions(+)
> create mode 100644 tests/acceptance/reverse_debugging.py
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ea4fa3e481..bd3a7efb75 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2693,6 +2693,7 @@ F: include/sysemu/replay.h
> F: docs/replay.txt
> F: stubs/replay.c
> F: tests/acceptance/replay_kernel.py
> +F: tests/acceptance/reverse_debugging.py
> F: qapi/replay.json
>
> IOVA Tree
> diff --git a/tests/acceptance/reverse_debugging.py b/tests/acceptance/reverse_debugging.py
> new file mode 100644
> index 0000000000..b72fdf6cdc
> --- /dev/null
> +++ b/tests/acceptance/reverse_debugging.py
> @@ -0,0 +1,208 @@
> +# Reverse debugging test
> +#
> +# Copyright (c) 2020 ISP RAS
> +#
> +# Author:
> +# Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2 or
> +# later. See the COPYING file in the top-level directory.
> +import os
> +import logging
> +
> +from avocado import skipIf
> +from avocado_qemu import BUILD_DIR
> +from avocado.utils import gdb
> +from avocado.utils import process
> +from avocado.utils.path import find_command
> +from boot_linux_console import LinuxKernelTest
> +
> +class ReverseDebugging(LinuxKernelTest):
> + """
> + Test GDB reverse debugging commands: reverse step and reverse continue.
> + Recording saves the execution of some instructions and makes an initial
> + VM snapshot to allow reverse execution.
> + Replay saves the order of the first instructions and then checks that they
> + are executed backwards in the correct order.
> + After that the execution is replayed to the end, and reverse continue
> + command is checked by setting several breakpoints, and asserting
> + that the execution is stopped at the last of them.
> + """
> +
> + timeout = 10
> + STEPS = 10
> + endian_is_le = True
Have you attmepted a "be" test too? I'm curious about why this is
defined (and used later) but it's never used as `False`.
> +
> + def run_vm(self, record, shift, args, replay_path, image_path):
> + logger = logging.getLogger('replay')
> + vm = self.get_vm()
> + vm.set_console()
> + if record:
> + logger.info('recording the execution...')
> + mode = 'record'
> + else:
> + logger.info('replaying the execution...')
> + mode = 'replay'
> + vm.add_args('-s', '-S')
> + vm.add_args('-icount', 'shift=%s,rr=%s,rrfile=%s,rrsnapshot=init' %
> + (shift, mode, replay_path),
> + '-net', 'none')
> + vm.add_args('-drive', 'file=%s,if=none' % image_path)
> + if args:
> + vm.add_args(*args)
> + vm.launch()
> + return vm
> +
> + @staticmethod
> + def get_reg_le(g, reg):
> + res = g.cmd(b'p%x' % reg)
> + num = 0
> + for i in range(len(res))[-2::-2]:
> + num = 0x100 * num + int(res[i:i + 2], 16)
> + return num
> +
> + @staticmethod
> + def get_reg_be(g, reg):
> + res = g.cmd(b'p%x' % reg)
> + return int(res, 16)
> +
> + def get_reg(self, g, reg):
> + # value may be encoded in BE or LE order
> + if self.endian_is_le:
> + return self.get_reg_le(g, reg)
> + else:
> + return self.get_reg_be(g, reg)
> +
> + def get_pc(self, g):
> + return self.get_reg(g, self.REG_PC)
> +
> + def check_pc(self, g, addr):
> + pc = self.get_pc(g)
> + if pc != addr:
> + self.fail('Invalid PC (read %x instead of %x)' % (pc, addr))
> +
> + @staticmethod
> + def gdb_step(g):
> + g.cmd(b's', b'T05thread:01;')
> +
> + @staticmethod
> + def gdb_bstep(g):
> + g.cmd(b'bs', b'T05thread:01;')
> +
> + @staticmethod
> + def vm_get_icount(vm):
> + return vm.qmp('query-replay')['return']['icount']
> +
> + def reverse_debugging(self, shift=7, args=None):
> + logger = logging.getLogger('replay')
> +
> + # create qcow2 for snapshots
> + logger.info('creating qcow2 image for VM snapshots')
> + image_path = os.path.join(self.workdir, 'disk.qcow2')
> + qemu_img = os.path.join(BUILD_DIR, 'qemu-img')
> + if not os.path.exists(qemu_img):
> + qemu_img = find_command('qemu-img', False)
> + if qemu_img is False:
> + self.cancel('Could not find "qemu-img", which is required to '
> + 'create the temporary qcow2 image')
This snippet is clearly modeled after the snippet in
`boot_linux.BootLinuxBase.download_boot()`. I'm adding an action
item to create a generic utility:
https://gitlab.com/cleber.gnu/qemu/-/issues/1
> + cmd = '%s create -f qcow2 %s 128M' % (qemu_img, image_path)
> + process.run(cmd)
> +
> + replay_path = os.path.join(self.workdir, 'replay.bin')
> +
> + # record the log
> + vm = self.run_vm(True, shift, args, replay_path, image_path)
> + while self.vm_get_icount(vm) <= self.STEPS:
> + pass
> + last_icount = self.vm_get_icount(vm)
> + vm.shutdown()
> +
> + logger.info("recorded log with %s+ steps" % last_icount)
> +
> + # replay and run debug commands
> + vm = self.run_vm(False, shift, args, replay_path, image_path)
> + logger.info('connecting to gdbstub')
> + g = gdb.GDBRemote('127.0.0.1', 1234, False, False)
> + g.connect()
> + r = g.cmd(b'qSupported')
> + if b'qXfer:features:read+' in r:
> + g.cmd(b'qXfer:features:read:target.xml:0,ffb')
> + if b'ReverseStep+' not in r:
> + self.fail('Reverse step is not supported by QEMU')
> + if b'ReverseContinue+' not in r:
> + self.fail('Reverse continue is not supported by QEMU')
> +
> + logger.info('stepping forward')
> + steps = []
> + # record first instruction addresses
> + for _ in range(self.STEPS):
> + pc = self.get_pc(g)
> + logger.info('saving position %x' % pc)
> + steps.append(pc)
> + self.gdb_step(g)
Do you think it'd make sense to have more utility methods, such as
`step()` and `bstep()` in `avocado.utils.gdb.GDBRemote` itself?
> +
> + # visit the recorded instruction in reverse order
> + logger.info('stepping backward')
> + for addr in steps[::-1]:
> + self.gdb_bstep(g)
> + self.check_pc(g, addr)
> + logger.info('found position %x' % addr)
> +
> + logger.info('seeking to the end (icount %s)' % (last_icount - 1))
> + vm.qmp('replay-break', icount=last_icount - 1)
> + # continue - will return after pausing
> + g.cmd(b'c', b'T02thread:01;')
> +
> + logger.info('setting breakpoints')
> + for addr in steps:
> + # hardware breakpoint at addr with len=1
> + g.cmd(b'Z1,%x,1' % addr, b'OK')
> +
> + logger.info('running reverse continue to reach %x' % steps[-1])
> + # reverse continue - will return after stopping at the breakpoint
> + g.cmd(b'bc', b'T05thread:01;')
> +
> + # assume that none of the first instructions is executed again
> + # breaking the order of the breakpoints
> + self.check_pc(g, steps[-1])
> + logger.info('successfully reached %x' % steps[-1])
> +
> + logger.info('exitting gdb and qemu')
> + vm.shutdown()
> +
> +class ReverseDebugging_X86_64(ReverseDebugging):
> + REG_PC = 0x10
> + REG_CS = 0x12
> + def get_pc(self, g):
> + return self.get_reg_le(g, self.REG_PC) \
> + + self.get_reg_le(g, self.REG_CS) * 0x10
> +
Nitpick: avoid backslash as line continuation, and favor parentheses,
that is:
def get_pc(self, g):
return (self.get_reg_le(g, self.REG_PC) +
self.get_reg_le(g, self.REG_CS) * 0x10)
Despite the comments and questions, this LGTM:
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
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^ permalink raw reply [flat|nested] 24+ messages in thread* Re: [PATCH v7 14/14] tests/acceptance: add reverse debugging test
2020-10-06 13:36 ` Cleber Rosa
@ 2020-10-06 15:09 ` Pavel Dovgalyuk
2020-10-06 18:16 ` Cleber Rosa
0 siblings, 1 reply; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-06 15:09 UTC (permalink / raw)
To: Cleber Rosa
Cc: kwolf, wrampazz, ehabkost, alex.bennee, mtosatti, qemu-devel,
armbru, stefanha, pbonzini, mreitz, philmd, zhiwei_liu, rth
On 06.10.2020 16:36, Cleber Rosa wrote:
> On Sat, Oct 03, 2020 at 08:14:06PM +0300, Pavel Dovgalyuk wrote:
>> From: Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>
>>
>> This is a test for GDB reverse debugging commands: reverse step and reverse continue.
>> Every test in this suite consists of two phases: record and replay.
>> Recording saves the execution of some instructions and makes an initial
>> VM snapshot to allow reverse execution.
>> Replay saves the order of the first instructions and then checks that they
>> are executed backwards in the correct order.
>> After that the execution is replayed to the end, and reverse continue
>> command is checked by setting several breakpoints, and asserting
>> that the execution is stopped at the last of them.
>>
>> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
>> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Reviewed-by: Willian Rampazzo <willianr@redhat.com>
>>
>> --
>>
>> v5:
>> - disabled (as some other tests) when running on gitlab
>> due to the unidentified timeout problem
>> ---
>> MAINTAINERS | 1
>> tests/acceptance/reverse_debugging.py | 208 +++++++++++++++++++++++++++++++++
>> 2 files changed, 209 insertions(+)
>> create mode 100644 tests/acceptance/reverse_debugging.py
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index ea4fa3e481..bd3a7efb75 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -2693,6 +2693,7 @@ F: include/sysemu/replay.h
>> F: docs/replay.txt
>> F: stubs/replay.c
>> F: tests/acceptance/replay_kernel.py
>> +F: tests/acceptance/reverse_debugging.py
>> F: qapi/replay.json
>>
>> IOVA Tree
>> diff --git a/tests/acceptance/reverse_debugging.py b/tests/acceptance/reverse_debugging.py
>> new file mode 100644
>> index 0000000000..b72fdf6cdc
>> --- /dev/null
>> +++ b/tests/acceptance/reverse_debugging.py
>> @@ -0,0 +1,208 @@
>> +# Reverse debugging test
>> +#
>> +# Copyright (c) 2020 ISP RAS
>> +#
>> +# Author:
>> +# Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
>> +#
>> +# This work is licensed under the terms of the GNU GPL, version 2 or
>> +# later. See the COPYING file in the top-level directory.
>> +import os
>> +import logging
>> +
>> +from avocado import skipIf
>> +from avocado_qemu import BUILD_DIR
>> +from avocado.utils import gdb
>> +from avocado.utils import process
>> +from avocado.utils.path import find_command
>> +from boot_linux_console import LinuxKernelTest
>> +
>> +class ReverseDebugging(LinuxKernelTest):
>> + """
>> + Test GDB reverse debugging commands: reverse step and reverse continue.
>> + Recording saves the execution of some instructions and makes an initial
>> + VM snapshot to allow reverse execution.
>> + Replay saves the order of the first instructions and then checks that they
>> + are executed backwards in the correct order.
>> + After that the execution is replayed to the end, and reverse continue
>> + command is checked by setting several breakpoints, and asserting
>> + that the execution is stopped at the last of them.
>> + """
>> +
>> + timeout = 10
>> + STEPS = 10
>> + endian_is_le = True
>
> Have you attmepted a "be" test too? I'm curious about why this is
> defined (and used later) but it's never used as `False`.
It was intended to be used with PPC, but PPCs record-replay is not
reliable enough.
>
>> +
>> + def run_vm(self, record, shift, args, replay_path, image_path):
>> + logger = logging.getLogger('replay')
>> + vm = self.get_vm()
>> + vm.set_console()
>> + if record:
>> + logger.info('recording the execution...')
>> + mode = 'record'
>> + else:
>> + logger.info('replaying the execution...')
>> + mode = 'replay'
>> + vm.add_args('-s', '-S')
>> + vm.add_args('-icount', 'shift=%s,rr=%s,rrfile=%s,rrsnapshot=init' %
>> + (shift, mode, replay_path),
>> + '-net', 'none')
>> + vm.add_args('-drive', 'file=%s,if=none' % image_path)
>> + if args:
>> + vm.add_args(*args)
>> + vm.launch()
>> + return vm
>> +
>> + @staticmethod
>> + def get_reg_le(g, reg):
>> + res = g.cmd(b'p%x' % reg)
>> + num = 0
>> + for i in range(len(res))[-2::-2]:
>> + num = 0x100 * num + int(res[i:i + 2], 16)
>> + return num
>> +
>> + @staticmethod
>> + def get_reg_be(g, reg):
>> + res = g.cmd(b'p%x' % reg)
>> + return int(res, 16)
>> +
>> + def get_reg(self, g, reg):
>> + # value may be encoded in BE or LE order
>> + if self.endian_is_le:
>> + return self.get_reg_le(g, reg)
>> + else:
>> + return self.get_reg_be(g, reg)
>> +
>> + def get_pc(self, g):
>> + return self.get_reg(g, self.REG_PC)
>> +
>> + def check_pc(self, g, addr):
>> + pc = self.get_pc(g)
>> + if pc != addr:
>> + self.fail('Invalid PC (read %x instead of %x)' % (pc, addr))
>> +
>> + @staticmethod
>> + def gdb_step(g):
>> + g.cmd(b's', b'T05thread:01;')
>> +
>> + @staticmethod
>> + def gdb_bstep(g):
>> + g.cmd(b'bs', b'T05thread:01;')
>> +
>> + @staticmethod
>> + def vm_get_icount(vm):
>> + return vm.qmp('query-replay')['return']['icount']
>> +
>> + def reverse_debugging(self, shift=7, args=None):
>> + logger = logging.getLogger('replay')
>> +
>> + # create qcow2 for snapshots
>> + logger.info('creating qcow2 image for VM snapshots')
>> + image_path = os.path.join(self.workdir, 'disk.qcow2')
>> + qemu_img = os.path.join(BUILD_DIR, 'qemu-img')
>> + if not os.path.exists(qemu_img):
>> + qemu_img = find_command('qemu-img', False)
>> + if qemu_img is False:
>> + self.cancel('Could not find "qemu-img", which is required to '
>> + 'create the temporary qcow2 image')
>
> This snippet is clearly modeled after the snippet in
> `boot_linux.BootLinuxBase.download_boot()`. I'm adding an action
> item to create a generic utility:
>
> https://gitlab.com/cleber.gnu/qemu/-/issues/1
>
>> + cmd = '%s create -f qcow2 %s 128M' % (qemu_img, image_path)
>> + process.run(cmd)
>> +
>> + replay_path = os.path.join(self.workdir, 'replay.bin')
>> +
>> + # record the log
>> + vm = self.run_vm(True, shift, args, replay_path, image_path)
>> + while self.vm_get_icount(vm) <= self.STEPS:
>> + pass
>> + last_icount = self.vm_get_icount(vm)
>> + vm.shutdown()
>> +
>> + logger.info("recorded log with %s+ steps" % last_icount)
>> +
>> + # replay and run debug commands
>> + vm = self.run_vm(False, shift, args, replay_path, image_path)
>> + logger.info('connecting to gdbstub')
>> + g = gdb.GDBRemote('127.0.0.1', 1234, False, False)
>> + g.connect()
>> + r = g.cmd(b'qSupported')
>> + if b'qXfer:features:read+' in r:
>> + g.cmd(b'qXfer:features:read:target.xml:0,ffb')
>> + if b'ReverseStep+' not in r:
>> + self.fail('Reverse step is not supported by QEMU')
>> + if b'ReverseContinue+' not in r:
>> + self.fail('Reverse continue is not supported by QEMU')
>> +
>> + logger.info('stepping forward')
>> + steps = []
>> + # record first instruction addresses
>> + for _ in range(self.STEPS):
>> + pc = self.get_pc(g)
>> + logger.info('saving position %x' % pc)
>> + steps.append(pc)
>> + self.gdb_step(g)
>
> Do you think it'd make sense to have more utility methods, such as
> `step()` and `bstep()` in `avocado.utils.gdb.GDBRemote` itself?
I thought about it, but it was easier to not have the dependency on
newer avocado version.
But now we can move these functions into avocado in two steps.
>
>> +
>> + # visit the recorded instruction in reverse order
>> + logger.info('stepping backward')
>> + for addr in steps[::-1]:
>> + self.gdb_bstep(g)
>> + self.check_pc(g, addr)
>> + logger.info('found position %x' % addr)
>> +
>> + logger.info('seeking to the end (icount %s)' % (last_icount - 1))
>> + vm.qmp('replay-break', icount=last_icount - 1)
>> + # continue - will return after pausing
>> + g.cmd(b'c', b'T02thread:01;')
>> +
>> + logger.info('setting breakpoints')
>> + for addr in steps:
>> + # hardware breakpoint at addr with len=1
>> + g.cmd(b'Z1,%x,1' % addr, b'OK')
>> +
>> + logger.info('running reverse continue to reach %x' % steps[-1])
>> + # reverse continue - will return after stopping at the breakpoint
>> + g.cmd(b'bc', b'T05thread:01;')
>> +
>> + # assume that none of the first instructions is executed again
>> + # breaking the order of the breakpoints
>> + self.check_pc(g, steps[-1])
>> + logger.info('successfully reached %x' % steps[-1])
>> +
>> + logger.info('exitting gdb and qemu')
>> + vm.shutdown()
>> +
>> +class ReverseDebugging_X86_64(ReverseDebugging):
>> + REG_PC = 0x10
>> + REG_CS = 0x12
>> + def get_pc(self, g):
>> + return self.get_reg_le(g, self.REG_PC) \
>> + + self.get_reg_le(g, self.REG_CS) * 0x10
>> +
>
> Nitpick: avoid backslash as line continuation, and favor parentheses,
> that is:
>
> def get_pc(self, g):
> return (self.get_reg_le(g, self.REG_PC) +
> self.get_reg_le(g, self.REG_CS) * 0x10)
>
> Despite the comments and questions, this LGTM:
>
> Reviewed-by: Cleber Rosa <crosa@redhat.com>
> Tested-by: Cleber Rosa <crosa@redhat.com>
>
^ permalink raw reply [flat|nested] 24+ messages in thread* Re: [PATCH v7 14/14] tests/acceptance: add reverse debugging test
2020-10-06 15:09 ` Pavel Dovgalyuk
@ 2020-10-06 18:16 ` Cleber Rosa
0 siblings, 0 replies; 24+ messages in thread
From: Cleber Rosa @ 2020-10-06 18:16 UTC (permalink / raw)
To: Pavel Dovgalyuk
Cc: kwolf, wrampazz, ehabkost, alex.bennee, mtosatti, qemu-devel,
armbru, stefanha, pbonzini, mreitz, philmd, zhiwei_liu, rth
[-- Attachment #1: Type: text/plain, Size: 9502 bytes --]
On Tue, Oct 06, 2020 at 06:09:55PM +0300, Pavel Dovgalyuk wrote:
> On 06.10.2020 16:36, Cleber Rosa wrote:
> > On Sat, Oct 03, 2020 at 08:14:06PM +0300, Pavel Dovgalyuk wrote:
> > > From: Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>
> > >
> > > This is a test for GDB reverse debugging commands: reverse step and reverse continue.
> > > Every test in this suite consists of two phases: record and replay.
> > > Recording saves the execution of some instructions and makes an initial
> > > VM snapshot to allow reverse execution.
> > > Replay saves the order of the first instructions and then checks that they
> > > are executed backwards in the correct order.
> > > After that the execution is replayed to the end, and reverse continue
> > > command is checked by setting several breakpoints, and asserting
> > > that the execution is stopped at the last of them.
> > >
> > > Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> > > Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> > > Reviewed-by: Willian Rampazzo <willianr@redhat.com>
> > >
> > > --
> > >
> > > v5:
> > > - disabled (as some other tests) when running on gitlab
> > > due to the unidentified timeout problem
> > > ---
> > > MAINTAINERS | 1
> > > tests/acceptance/reverse_debugging.py | 208 +++++++++++++++++++++++++++++++++
> > > 2 files changed, 209 insertions(+)
> > > create mode 100644 tests/acceptance/reverse_debugging.py
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index ea4fa3e481..bd3a7efb75 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -2693,6 +2693,7 @@ F: include/sysemu/replay.h
> > > F: docs/replay.txt
> > > F: stubs/replay.c
> > > F: tests/acceptance/replay_kernel.py
> > > +F: tests/acceptance/reverse_debugging.py
> > > F: qapi/replay.json
> > > IOVA Tree
> > > diff --git a/tests/acceptance/reverse_debugging.py b/tests/acceptance/reverse_debugging.py
> > > new file mode 100644
> > > index 0000000000..b72fdf6cdc
> > > --- /dev/null
> > > +++ b/tests/acceptance/reverse_debugging.py
> > > @@ -0,0 +1,208 @@
> > > +# Reverse debugging test
> > > +#
> > > +# Copyright (c) 2020 ISP RAS
> > > +#
> > > +# Author:
> > > +# Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> > > +#
> > > +# This work is licensed under the terms of the GNU GPL, version 2 or
> > > +# later. See the COPYING file in the top-level directory.
> > > +import os
> > > +import logging
> > > +
> > > +from avocado import skipIf
> > > +from avocado_qemu import BUILD_DIR
> > > +from avocado.utils import gdb
> > > +from avocado.utils import process
> > > +from avocado.utils.path import find_command
> > > +from boot_linux_console import LinuxKernelTest
> > > +
> > > +class ReverseDebugging(LinuxKernelTest):
> > > + """
> > > + Test GDB reverse debugging commands: reverse step and reverse continue.
> > > + Recording saves the execution of some instructions and makes an initial
> > > + VM snapshot to allow reverse execution.
> > > + Replay saves the order of the first instructions and then checks that they
> > > + are executed backwards in the correct order.
> > > + After that the execution is replayed to the end, and reverse continue
> > > + command is checked by setting several breakpoints, and asserting
> > > + that the execution is stopped at the last of them.
> > > + """
> > > +
> > > + timeout = 10
> > > + STEPS = 10
> > > + endian_is_le = True
> >
> > Have you attmepted a "be" test too? I'm curious about why this is
> > defined (and used later) but it's never used as `False`.
>
> It was intended to be used with PPC, but PPCs record-replay is not reliable
> enough.
>
OK, thanks for the explanation.
> >
> > > +
> > > + def run_vm(self, record, shift, args, replay_path, image_path):
> > > + logger = logging.getLogger('replay')
> > > + vm = self.get_vm()
> > > + vm.set_console()
> > > + if record:
> > > + logger.info('recording the execution...')
> > > + mode = 'record'
> > > + else:
> > > + logger.info('replaying the execution...')
> > > + mode = 'replay'
> > > + vm.add_args('-s', '-S')
> > > + vm.add_args('-icount', 'shift=%s,rr=%s,rrfile=%s,rrsnapshot=init' %
> > > + (shift, mode, replay_path),
> > > + '-net', 'none')
> > > + vm.add_args('-drive', 'file=%s,if=none' % image_path)
> > > + if args:
> > > + vm.add_args(*args)
> > > + vm.launch()
> > > + return vm
> > > +
> > > + @staticmethod
> > > + def get_reg_le(g, reg):
> > > + res = g.cmd(b'p%x' % reg)
> > > + num = 0
> > > + for i in range(len(res))[-2::-2]:
> > > + num = 0x100 * num + int(res[i:i + 2], 16)
> > > + return num
> > > +
> > > + @staticmethod
> > > + def get_reg_be(g, reg):
> > > + res = g.cmd(b'p%x' % reg)
> > > + return int(res, 16)
> > > +
> > > + def get_reg(self, g, reg):
> > > + # value may be encoded in BE or LE order
> > > + if self.endian_is_le:
> > > + return self.get_reg_le(g, reg)
> > > + else:
> > > + return self.get_reg_be(g, reg)
> > > +
> > > + def get_pc(self, g):
> > > + return self.get_reg(g, self.REG_PC)
> > > +
> > > + def check_pc(self, g, addr):
> > > + pc = self.get_pc(g)
> > > + if pc != addr:
> > > + self.fail('Invalid PC (read %x instead of %x)' % (pc, addr))
> > > +
> > > + @staticmethod
> > > + def gdb_step(g):
> > > + g.cmd(b's', b'T05thread:01;')
> > > +
> > > + @staticmethod
> > > + def gdb_bstep(g):
> > > + g.cmd(b'bs', b'T05thread:01;')
> > > +
> > > + @staticmethod
> > > + def vm_get_icount(vm):
> > > + return vm.qmp('query-replay')['return']['icount']
> > > +
> > > + def reverse_debugging(self, shift=7, args=None):
> > > + logger = logging.getLogger('replay')
> > > +
> > > + # create qcow2 for snapshots
> > > + logger.info('creating qcow2 image for VM snapshots')
> > > + image_path = os.path.join(self.workdir, 'disk.qcow2')
> > > + qemu_img = os.path.join(BUILD_DIR, 'qemu-img')
> > > + if not os.path.exists(qemu_img):
> > > + qemu_img = find_command('qemu-img', False)
> > > + if qemu_img is False:
> > > + self.cancel('Could not find "qemu-img", which is required to '
> > > + 'create the temporary qcow2 image')
> >
> > This snippet is clearly modeled after the snippet in
> > `boot_linux.BootLinuxBase.download_boot()`. I'm adding an action
> > item to create a generic utility:
> >
> > https://gitlab.com/cleber.gnu/qemu/-/issues/1
> >
> > > + cmd = '%s create -f qcow2 %s 128M' % (qemu_img, image_path)
> > > + process.run(cmd)
> > > +
> > > + replay_path = os.path.join(self.workdir, 'replay.bin')
> > > +
> > > + # record the log
> > > + vm = self.run_vm(True, shift, args, replay_path, image_path)
> > > + while self.vm_get_icount(vm) <= self.STEPS:
> > > + pass
> > > + last_icount = self.vm_get_icount(vm)
> > > + vm.shutdown()
> > > +
> > > + logger.info("recorded log with %s+ steps" % last_icount)
> > > +
> > > + # replay and run debug commands
> > > + vm = self.run_vm(False, shift, args, replay_path, image_path)
> > > + logger.info('connecting to gdbstub')
> > > + g = gdb.GDBRemote('127.0.0.1', 1234, False, False)
> > > + g.connect()
> > > + r = g.cmd(b'qSupported')
> > > + if b'qXfer:features:read+' in r:
> > > + g.cmd(b'qXfer:features:read:target.xml:0,ffb')
> > > + if b'ReverseStep+' not in r:
> > > + self.fail('Reverse step is not supported by QEMU')
> > > + if b'ReverseContinue+' not in r:
> > > + self.fail('Reverse continue is not supported by QEMU')
> > > +
> > > + logger.info('stepping forward')
> > > + steps = []
> > > + # record first instruction addresses
> > > + for _ in range(self.STEPS):
> > > + pc = self.get_pc(g)
> > > + logger.info('saving position %x' % pc)
> > > + steps.append(pc)
> > > + self.gdb_step(g)
> >
> > Do you think it'd make sense to have more utility methods, such as
> > `step()` and `bstep()` in `avocado.utils.gdb.GDBRemote` itself?
>
> I thought about it, but it was easier to not have the dependency on newer
> avocado version.
Agreed.
> But now we can move these functions into avocado in two steps.
>
OK. I think the versions of these functions in
`avocado.utils.gdb.GDBRemote` can benefit from parsing the reply
packets. With that, in addition to using a strict expected reponse
(like you've done with b'T05thread:01;') the caller may inspect
only the aspects that it deems important.
For instance, one may be interested in asserting that the signal
was a SIGTRAP, but may not care about the thread ID.
Anyway, I'm opening an issue on the Avocado project page:
https://github.com/avocado-framework/avocado/issues/4258
If you have ideas about the interface, please let me know.
Thanks,
- Cleber.
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v7 14/14] tests/acceptance: add reverse debugging test
2020-10-03 17:14 ` [PATCH v7 14/14] tests/acceptance: add reverse debugging test Pavel Dovgalyuk
2020-10-06 13:36 ` Cleber Rosa
@ 2020-10-06 19:55 ` Philippe Mathieu-Daudé
2020-10-07 5:42 ` Philippe Mathieu-Daudé
1 sibling, 1 reply; 24+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-10-06 19:55 UTC (permalink / raw)
To: Pavel Dovgalyuk, qemu-devel
Cc: kwolf, wrampazz, ehabkost, mtosatti, armbru, mreitz, stefanha,
crosa, pbonzini, alex.bennee, zhiwei_liu, rth
On 10/3/20 7:14 PM, Pavel Dovgalyuk wrote:
> From: Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>
>
> This is a test for GDB reverse debugging commands: reverse step and reverse continue.
> Every test in this suite consists of two phases: record and replay.
> Recording saves the execution of some instructions and makes an initial
> VM snapshot to allow reverse execution.
> Replay saves the order of the first instructions and then checks that they
> are executed backwards in the correct order.
> After that the execution is replayed to the end, and reverse continue
> command is checked by setting several breakpoints, and asserting
> that the execution is stopped at the last of them.
>
> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Reviewed-by: Willian Rampazzo <willianr@redhat.com>
>
> --
>
> v5:
> - disabled (as some other tests) when running on gitlab
> due to the unidentified timeout problem
> ---
> MAINTAINERS | 1
> tests/acceptance/reverse_debugging.py | 208 +++++++++++++++++++++++++++++++++
> 2 files changed, 209 insertions(+)
> create mode 100644 tests/acceptance/reverse_debugging.py
Thanks, applied to my acceptance-testing tree.
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v7 14/14] tests/acceptance: add reverse debugging test
2020-10-06 19:55 ` Philippe Mathieu-Daudé
@ 2020-10-07 5:42 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 24+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-10-07 5:42 UTC (permalink / raw)
To: Pavel Dovgalyuk, qemu-devel
Cc: kwolf, wrampazz, ehabkost, mtosatti, armbru, mreitz, stefanha,
crosa, pbonzini, alex.bennee, zhiwei_liu, rth
On 10/6/20 9:55 PM, Philippe Mathieu-Daudé wrote:
> On 10/3/20 7:14 PM, Pavel Dovgalyuk wrote:
>> From: Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>
>>
>> This is a test for GDB reverse debugging commands: reverse step and reverse continue.
>> Every test in this suite consists of two phases: record and replay.
>> Recording saves the execution of some instructions and makes an initial
>> VM snapshot to allow reverse execution.
>> Replay saves the order of the first instructions and then checks that they
>> are executed backwards in the correct order.
>> After that the execution is replayed to the end, and reverse continue
>> command is checked by setting several breakpoints, and asserting
>> that the execution is stopped at the last of them.
>>
>> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
>> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Reviewed-by: Willian Rampazzo <willianr@redhat.com>
>>
>> --
This separator confuses the git tools. Can you stop using it
and use the '---' one instead?
>>
>> v5:
>> - disabled (as some other tests) when running on gitlab
>> due to the unidentified timeout problem
^ this should be stripped automatically but isn't.
>> ---
>> MAINTAINERS | 1
>> tests/acceptance/reverse_debugging.py | 208 +++++++++++++++++++++++++++++++++
>> 2 files changed, 209 insertions(+)
>> create mode 100644 tests/acceptance/reverse_debugging.py
>
> Thanks, applied to my acceptance-testing tree.
This patch as already be merged by Paolo as commit be52eca309
("tests/acceptance: add reverse debugging test").
The notes below your '--' separator have been merged too.
Dirty, but not a big deal.
Regards,
Phil.
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v7 00/14] Reverse debugging
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (13 preceding siblings ...)
2020-10-03 17:14 ` [PATCH v7 14/14] tests/acceptance: add reverse debugging test Pavel Dovgalyuk
@ 2020-10-04 1:06 ` no-reply
2020-10-05 12:27 ` Paolo Bonzini
15 siblings, 0 replies; 24+ messages in thread
From: no-reply @ 2020-10-04 1:06 UTC (permalink / raw)
To: pavel.dovgalyuk
Cc: kwolf, pavel.dovgalyuk, ehabkost, philmd, mtosatti, stefanha,
qemu-devel, armbru, wrampazz, crosa, pbonzini, mreitz,
alex.bennee, zhiwei_liu, rth
Patchew URL: https://patchew.org/QEMU/160174516520.12451.10785284392438702137.stgit@pasha-ThinkPad-X280/
Hi,
This series seems to have some coding style problems. See output below for
more information:
Type: series
Message-id: 160174516520.12451.10785284392438702137.stgit@pasha-ThinkPad-X280
Subject: [PATCH v7 00/14] Reverse debugging
=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===
Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
ba53a9d tests/acceptance: add reverse debugging test
c6aa9c5 replay: create temporary snapshot at debugger connection
17d5c46 replay: describe reverse debugging in docs/replay.txt
1f88bff gdbstub: add reverse continue support in replay mode
72ef5d6 gdbstub: add reverse step support in replay mode
42bf7cc replay: flush rr queue before loading the vmstate
4285666 replay: implement replay-seek command
653aa62 replay: introduce breakpoint at the specified step
59ab65a replay: introduce info hmp/qmp command
1bc0b45 qapi: introduce replay.json for record/replay-related stuff
c4b17f7 migration: introduce icount field for snapshots
03d28c5 qcow2: introduce icount field for snapshots
6de69ce replay: provide an accessor for rr filename
8ba3d42 replay: don't record interrupt poll
=== OUTPUT BEGIN ===
1/14 Checking commit 8ba3d42631d9 (replay: don't record interrupt poll)
2/14 Checking commit 6de69cee86b9 (replay: provide an accessor for rr filename)
3/14 Checking commit 03d28c50b445 (qcow2: introduce icount field for snapshots)
4/14 Checking commit c4b17f7373f0 (migration: introduce icount field for snapshots)
ERROR: trailing whitespace
#251: FILE: tests/qemu-iotests/267.out:37:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#262: FILE: tests/qemu-iotests/267.out:48:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#273: FILE: tests/qemu-iotests/267.out:73:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#284: FILE: tests/qemu-iotests/267.out:98:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#295: FILE: tests/qemu-iotests/267.out:109:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#306: FILE: tests/qemu-iotests/267.out:123:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#317: FILE: tests/qemu-iotests/267.out:138:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#328: FILE: tests/qemu-iotests/267.out:149:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#337: FILE: tests/qemu-iotests/267.out:156:
+1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#348: FILE: tests/qemu-iotests/267.out:170:
+-- snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#357: FILE: tests/qemu-iotests/267.out:177:
+1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
ERROR: trailing whitespace
#363: FILE: tests/qemu-iotests/267.out:181:
+1 snap0 SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000 $
total: 12 errors, 0 warnings, 275 lines checked
Patch 4/14 has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
5/14 Checking commit 1bc0b45203ea (qapi: introduce replay.json for record/replay-related stuff)
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#93:
new file mode 100644
total: 0 errors, 1 warnings, 78 lines checked
Patch 5/14 has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
6/14 Checking commit 59ab65a00e3b (replay: introduce info hmp/qmp command)
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#122:
new file mode 100644
total: 0 errors, 1 warnings, 120 lines checked
Patch 6/14 has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
7/14 Checking commit 653aa622c001 (replay: introduce breakpoint at the specified step)
8/14 Checking commit 4285666198ee (replay: implement replay-seek command)
9/14 Checking commit 42bf7cc3ae4e (replay: flush rr queue before loading the vmstate)
10/14 Checking commit 72ef5d64fb17 (gdbstub: add reverse step support in replay mode)
11/14 Checking commit 1f88bff3b6ee (gdbstub: add reverse continue support in replay mode)
12/14 Checking commit 17d5c466b4de (replay: describe reverse debugging in docs/replay.txt)
13/14 Checking commit c6aa9c57bfcf (replay: create temporary snapshot at debugger connection)
14/14 Checking commit ba53a9d9a49e (tests/acceptance: add reverse debugging test)
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#41:
new file mode 100644
total: 0 errors, 1 warnings, 215 lines checked
Patch 14/14 has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===
Test command exited with code: 1
The full log is available at
http://patchew.org/logs/160174516520.12451.10785284392438702137.stgit@pasha-ThinkPad-X280/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com
^ permalink raw reply [flat|nested] 24+ messages in thread* Re: [PATCH v7 00/14] Reverse debugging
2020-10-03 17:12 [PATCH v7 00/14] Reverse debugging Pavel Dovgalyuk
` (14 preceding siblings ...)
2020-10-04 1:06 ` [PATCH v7 00/14] Reverse debugging no-reply
@ 2020-10-05 12:27 ` Paolo Bonzini
2020-10-05 13:45 ` Pavel Dovgalyuk
15 siblings, 1 reply; 24+ messages in thread
From: Paolo Bonzini @ 2020-10-05 12:27 UTC (permalink / raw)
To: Pavel Dovgalyuk, qemu-devel
Cc: kwolf, wrampazz, ehabkost, alex.bennee, mtosatti, armbru, mreitz,
stefanha, crosa, philmd, zhiwei_liu, rth
On 03/10/20 19:12, Pavel Dovgalyuk wrote:
> GDB remote protocol supports reverse debugging of the targets.
> It includes 'reverse step' and 'reverse continue' operations.
> The first one finds the previous step of the execution,
> and the second one is intended to stop at the last breakpoint that
> would happen when the program is executed normally.
>
> Reverse debugging is possible in the replay mode, when at least
> one snapshot was created at the record or replay phase.
> QEMU can use these snapshots for travelling back in time with GDB.
>
> Running the execution in replay mode allows using GDB reverse debugging
> commands:
> - reverse-stepi (or rsi): Steps one instruction to the past.
> QEMU loads on of the prior snapshots and proceeds to the desired
> instruction forward. When that step is reaches, execution stops.
> - reverse-continue (or rc): Runs execution "backwards".
> QEMU tries to find breakpoint or watchpoint by loaded prior snapshot
> and replaying the execution. Then QEMU loads snapshots again and
> replays to the latest breakpoint. When there are no breakpoints in
> the examined section of the execution, QEMU finds one more snapshot
> and tries again. After the first snapshot is processed, execution
> stops at this snapshot.
>
> The set of patches include the following modifications:
> - gdbstub update for reverse debugging support
> - functions that automatically perform reverse step and reverse
> continue operations
> - hmp/qmp commands for manipulating the replay process
> - improvement of the snapshotting for saving the execution step
> in the snapshot parameters
> - avocado-based acceptance tests for reverse debugging
>
> The patches are available in the repository:
> https://github.com/ispras/qemu/tree/rr-200901
>
> v7 changes:
> - updated snapshot info output format
> - fixed qcow2 snapshot-related tests
Sorry, I'm still seeing a failure
timeout 15 /home/travis/build/bonzini/qemu/build/qemu-system-aarch64 -monitor none -display none -chardev file,path=memory-replay.out,id=output -icount shift=5,rr=replay,rrfile=record.bin -M virt -cpu max -display none -semihosting-config enable=on,target=native,chardev=output -kernel memory
qemu-system-aarch64: terminating on signal 15 from pid 38312 (timeout)
https://travis-ci.com/gitlab/bonzini/qemu/jobs/395029273
Paolo
^ permalink raw reply [flat|nested] 24+ messages in thread* Re: [PATCH v7 00/14] Reverse debugging
2020-10-05 12:27 ` Paolo Bonzini
@ 2020-10-05 13:45 ` Pavel Dovgalyuk
2020-10-05 13:51 ` Paolo Bonzini
0 siblings, 1 reply; 24+ messages in thread
From: Pavel Dovgalyuk @ 2020-10-05 13:45 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel
Cc: kwolf, wrampazz, ehabkost, alex.bennee, mtosatti, armbru, mreitz,
stefanha, crosa, philmd, zhiwei_liu, rth
On 05.10.2020 15:27, Paolo Bonzini wrote:
> On 03/10/20 19:12, Pavel Dovgalyuk wrote:
>> GDB remote protocol supports reverse debugging of the targets.
>> It includes 'reverse step' and 'reverse continue' operations.
>> The first one finds the previous step of the execution,
>> and the second one is intended to stop at the last breakpoint that
>> would happen when the program is executed normally.
>>
>> Reverse debugging is possible in the replay mode, when at least
>> one snapshot was created at the record or replay phase.
>> QEMU can use these snapshots for travelling back in time with GDB.
>>
>> Running the execution in replay mode allows using GDB reverse debugging
>> commands:
>> - reverse-stepi (or rsi): Steps one instruction to the past.
>> QEMU loads on of the prior snapshots and proceeds to the desired
>> instruction forward. When that step is reaches, execution stops.
>> - reverse-continue (or rc): Runs execution "backwards".
>> QEMU tries to find breakpoint or watchpoint by loaded prior snapshot
>> and replaying the execution. Then QEMU loads snapshots again and
>> replays to the latest breakpoint. When there are no breakpoints in
>> the examined section of the execution, QEMU finds one more snapshot
>> and tries again. After the first snapshot is processed, execution
>> stops at this snapshot.
>>
>> The set of patches include the following modifications:
>> - gdbstub update for reverse debugging support
>> - functions that automatically perform reverse step and reverse
>> continue operations
>> - hmp/qmp commands for manipulating the replay process
>> - improvement of the snapshotting for saving the execution step
>> in the snapshot parameters
>> - avocado-based acceptance tests for reverse debugging
>>
>> The patches are available in the repository:
>> https://github.com/ispras/qemu/tree/rr-200901
>>
>> v7 changes:
>> - updated snapshot info output format
>> - fixed qcow2 snapshot-related tests
>
> Sorry, I'm still seeing a failure
>
> timeout 15 /home/travis/build/bonzini/qemu/build/qemu-system-aarch64 -monitor none -display none -chardev file,path=memory-replay.out,id=output -icount shift=5,rr=replay,rrfile=record.bin -M virt -cpu max -display none -semihosting-config enable=on,target=native,chardev=output -kernel memory
>
> qemu-system-aarch64: terminating on signal 15 from pid 38312 (timeout)
That's very strange.
None of the patches affect RR for AArch64. Is this the real failure or
just a coincidence?
I also tried running this test on my local machine and got normal
execution time for replay:
real 0m0,968s
user 0m0,657s
sys 0m0,625s
By the way, this is an early RR test. Now we have more complex (and
easier to reproduce) avocado-based RR tests (for aarch64 too).
I.e. record and replay in this test are divided into two "tests",
and can cause races if running in parallel for some reason.
Shouldn't we just drop this one?
>
> https://travis-ci.com/gitlab/bonzini/qemu/jobs/395029273
>
> Paolo
>
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v7 00/14] Reverse debugging
2020-10-05 13:45 ` Pavel Dovgalyuk
@ 2020-10-05 13:51 ` Paolo Bonzini
0 siblings, 0 replies; 24+ messages in thread
From: Paolo Bonzini @ 2020-10-05 13:51 UTC (permalink / raw)
To: Pavel Dovgalyuk, qemu-devel
Cc: kwolf, wrampazz, ehabkost, alex.bennee, mtosatti, armbru, mreitz,
stefanha, crosa, philmd, zhiwei_liu, rth
On 05/10/20 15:45, Pavel Dovgalyuk wrote:
>
> That's very strange.
> None of the patches affect RR for AArch64. Is this the real failure or
> just a coincidence?
> I also tried running this test on my local machine and got normal
> execution time for replay:
> real 0m0,968s
> user 0m0,657s
> sys 0m0,625s
>
> By the way, this is an early RR test. Now we have more complex (and
> easier to reproduce) avocado-based RR tests (for aarch64 too).
> I.e. record and replay in this test are divided into two "tests",
> and can cause races if running in parallel for some reason.
Good to know. I'll keep this series in my tree so that it reruns, and
will keep an eye on whether I see similar failures in the next few days.
I have seen other similar timeouts (e.g. in xtensa test-timer) that
weren't related to RR so it's possible that it's a false positive.
> Shouldn't we just drop this one?
Feel free to send a patch to Alex for it.
Paolo
^ permalink raw reply [flat|nested] 24+ messages in thread