[Qemu-devel] [RFC PATCH v2 00/26] replay additions

[Qemu-devel] [RFC PATCH v2 00/26] replay additions

[Pavel Dovgalyuk]

Accidentally sent draft version of patches to the mailing list.
Please consider this one as the correct one.

This set of patches includex fixes from Alex Bennée for fixing
BQL and replay locks after inventing the MTTCG. It also includes some
additional replay patches that makes this set of fixes working.
It is also fixes some vmstate creation (and loading) issues
in record/replay modes:
 - VM start/stop fixes in replay mode
 - overlay creation for blkreplay filter
 - fixes for vmstate save/load in record/replay mode
 - fixes for host clock vmstate
 - fixes for icount timers vmstate

There is also a set of helper scripts written by Alex Bennée
for debugging the record/replay code.

v2 changes:
 - updated lock/unlock logic (as suggested by Paolo Bonzini)
 - updated cpu execution loop to avoid races in setting/resetting exit request (as suggested by Paolo Bonzini)
 - minor changes

---

Alex Bennée (12):
      target/arm/arm-powertctl: drop BQL assertions
      cpus: push BQL lock to qemu_*_wait_io_event
      cpus: only take BQL for sleeping threads
      replay/replay.c: bump REPLAY_VERSION again
      replay/replay-internal.c: track holding of replay_lock
      replay: make locking visible outside replay code
      replay: push replay_mutex_lock up the call tree
      scripts/qemu-gdb: add simple tcg lock status helper
      util/qemu-thread-*: add qemu_lock, locked and unlock trace events
      scripts/analyse-locks-simpletrace.py: script to analyse lock times
      scripts/replay-dump.py: replay log dumper
      scripts/qemu-gdb/timers.py: new helper to dump timer state

Pavel Dovgalyuk (14):
      block: implement bdrv_snapshot_goto for blkreplay
      blkreplay: create temporary overlay for underlaying devices
      replay: disable default snapshot for record/replay
      replay: fix processing async events
      replay: fixed replay_enable_events
      replay: fix save/load vm for non-empty queue
      replay: added replay log format description
      replay: make safe vmstop at record/replay
      replay: save prior value of the host clock
      icount: fixed saving/restoring of icount warp timers
      cpu-exec: don't overwrite exception_index
      cpu-exec: reset exit flag before calling cpu_exec_nocache
      replay: don't destroy mutex at exit
      replay: check return values of fwrite


 accel/kvm/kvm-all.c                  |    4 
 accel/tcg/cpu-exec.c                 |   99 ++++++-----
 block/blkreplay.c                    |   73 ++++++++
 cpus-common.c                        |   13 +
 cpus.c                               |  134 ++++++++++++---
 docs/replay.txt                      |   91 ++++++++++
 include/qemu/thread.h                |   14 +-
 include/qemu/timer.h                 |   14 ++
 include/sysemu/replay.h              |   19 ++
 migration/savevm.c                   |   13 +
 replay/replay-char.c                 |   21 +-
 replay/replay-events.c               |   30 +--
 replay/replay-internal.c             |   35 +++-
 replay/replay-internal.h             |    9 +
 replay/replay-snapshot.c             |    9 +
 replay/replay-time.c                 |   10 +
 replay/replay.c                      |   42 ++---
 scripts/analyse-locks-simpletrace.py |   99 +++++++++++
 scripts/qemu-gdb.py                  |    4 
 scripts/qemugdb/tcg.py               |   46 +++++
 scripts/qemugdb/timers.py            |   54 ++++++
 scripts/replay-dump.py               |  308 ++++++++++++++++++++++++++++++++++
 stubs/replay.c                       |   16 ++
 target/arm/arm-powerctl.c            |    8 -
 target/i386/hax-all.c                |    2 
 util/main-loop.c                     |   17 +-
 util/qemu-thread-posix.c             |   21 +-
 util/qemu-timer.c                    |   12 +
 util/trace-events                    |    7 -
 vl.c                                 |   12 +
 30 files changed, 1053 insertions(+), 183 deletions(-)
 create mode 100755 scripts/analyse-locks-simpletrace.py
 create mode 100644 scripts/qemugdb/tcg.py
 create mode 100644 scripts/qemugdb/timers.py
 create mode 100755 scripts/replay-dump.py

-- 
Pavel Dovgalyuk

[Qemu-devel] [RFC PATCHv2 01/26] block: implement bdrv_snapshot_goto for blkreplay

[Pavel Dovgalyuk]

From: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>

This patch enables making snapshots with blkreplay used in
block devices.
This function is required to make bdrv_snapshot_goto without
calling .bdrv_open which is not implemented.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>

---
 block/blkreplay.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/blkreplay.c b/block/blkreplay.c
index 61e44a1..82a88f8 100755
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -127,6 +127,12 @@ static int coroutine_fn blkreplay_co_flush(BlockDriverState *bs)
     return ret;
 }
 
+static int blkreplay_snapshot_goto(BlockDriverState *bs,
+                                   const char *snapshot_id)
+{
+    return bdrv_snapshot_goto(bs->file->bs, snapshot_id);
+}
+
 static BlockDriver bdrv_blkreplay = {
     .format_name            = "blkreplay",
     .protocol_name          = "blkreplay",
@@ -143,6 +149,8 @@ static BlockDriver bdrv_blkreplay = {
     .bdrv_co_pwrite_zeroes  = blkreplay_co_pwrite_zeroes,
     .bdrv_co_pdiscard       = blkreplay_co_pdiscard,
     .bdrv_co_flush          = blkreplay_co_flush,
+
+    .bdrv_snapshot_goto     = blkreplay_snapshot_goto,
 };
 
 static void bdrv_blkreplay_init(void)

[Qemu-devel] [RFC PATCHv2 02/26] blkreplay: create temporary overlay for underlaying devices

[Pavel Dovgalyuk]

From: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>

This patch allows using '-snapshot' behavior in record/replay mode.
blkreplay layer creates temporary overlays on top of underlaying
disk images. It is needed, because creating an overlay over blkreplay
breaks the determinism.
This patch creates similar temporary overlay (when it is needed)
under the blkreplay driver. Therefore all block operations are controlled
by blkreplay.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>

---
 block/blkreplay.c |   65 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 stubs/replay.c    |    1 +
 vl.c              |    2 +-
 3 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/block/blkreplay.c b/block/blkreplay.c
index 82a88f8..c489d50 100755
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -14,12 +14,69 @@
 #include "block/block_int.h"
 #include "sysemu/replay.h"
 #include "qapi/error.h"
+#include "qapi/qmp/qstring.h"
 
 typedef struct Request {
     Coroutine *co;
     QEMUBH *bh;
 } Request;
 
+static BlockDriverState *blkreplay_append_snapshot(BlockDriverState *bs,
+                                                   Error **errp)
+{
+    int ret;
+    BlockDriverState *bs_snapshot;
+    int64_t total_size;
+    QemuOpts *opts = NULL;
+    char tmp_filename[PATH_MAX + 1];
+    QDict *snapshot_options = qdict_new();
+
+    /* Prepare options QDict for the overlay file */
+    qdict_put(snapshot_options, "file.driver", qstring_from_str("file"));
+    qdict_put(snapshot_options, "driver", qstring_from_str("qcow2"));
+
+    /* Create temporary file */
+    ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not get temporary filename");
+        goto out;
+    }
+    qdict_put(snapshot_options, "file.filename",
+              qstring_from_str(tmp_filename));
+
+    /* Get the required size from the image */
+    total_size = bdrv_getlength(bs);
+    if (total_size < 0) {
+        error_setg_errno(errp, -total_size, "Could not get image size");
+        goto out;
+    }
+
+    opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, &error_abort);
+    qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
+    ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
+    qemu_opts_del(opts);
+    if (ret < 0) {
+        error_prepend(errp, "Could not create temporary overlay '%s': ",
+                      tmp_filename);
+        goto out;
+    }
+
+    bs_snapshot = bdrv_open(NULL, NULL, snapshot_options,
+                            BDRV_O_RDWR | BDRV_O_TEMPORARY, errp);
+    snapshot_options = NULL;
+    if (!bs_snapshot) {
+        goto out;
+    }
+
+    bdrv_append(bs_snapshot, bs, errp);
+
+    return bs_snapshot;
+
+out:
+    QDECREF(snapshot_options);
+    return NULL;
+}
+
 static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags,
                           Error **errp)
 {
@@ -35,6 +92,14 @@ static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags,
         goto fail;
     }
 
+    /* Add temporary snapshot to preserve the image */
+    if (!replay_snapshot
+        && !blkreplay_append_snapshot(bs->file->bs, &local_err)) {
+        ret = -EINVAL;
+        error_propagate(errp, local_err);
+        goto fail;
+    }
+
     ret = 0;
 fail:
     return ret;
diff --git a/stubs/replay.c b/stubs/replay.c
index 9c8aa48..9991ee5 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -3,6 +3,7 @@
 #include "sysemu/sysemu.h"
 
 ReplayMode replay_mode;
+char *replay_snapshot;
 
 int64_t replay_save_clock(unsigned int kind, int64_t clock)
 {
diff --git a/vl.c b/vl.c
index ec29909..7aa59f0 100644
--- a/vl.c
+++ b/vl.c
@@ -4661,7 +4661,7 @@ int main(int argc, char **argv, char **envp)
         qapi_free_BlockdevOptions(bdo->bdo);
         g_free(bdo);
     }
-    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
+    if (snapshot) {
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
                           NULL, NULL);
     }

[Qemu-devel] [RFC PATCHv2 00/26] replay additions

[Pavel Dovgalyuk]

Accidentally sent draft version of patches to the mailing list.
Please consider this one as the correct one.

This set of patches includex fixes from Alex Bennée for fixing
BQL and replay locks after inventing the MTTCG. It also includes some
additional replay patches that makes this set of fixes working.
It is also fixes some vmstate creation (and loading) issues
in record/replay modes:
 - VM start/stop fixes in replay mode
 - overlay creation for blkreplay filter
 - fixes for vmstate save/load in record/replay mode
 - fixes for host clock vmstate
 - fixes for icount timers vmstate

There is also a set of helper scripts written by Alex Bennée
for debugging the record/replay code.

v2 changes:
 - updated lock/unlock logic (as suggested by Paolo Bonzini)
 - updated cpu execution loop to avoid races in setting/resetting exit request (as suggested by Paolo Bonzini)
 - minor changes

---

Alex Bennée (12):
      target/arm/arm-powertctl: drop BQL assertions
      cpus: push BQL lock to qemu_*_wait_io_event
      cpus: only take BQL for sleeping threads
      replay/replay.c: bump REPLAY_VERSION again
      replay/replay-internal.c: track holding of replay_lock
      replay: make locking visible outside replay code
      replay: push replay_mutex_lock up the call tree
      scripts/qemu-gdb: add simple tcg lock status helper
      util/qemu-thread-*: add qemu_lock, locked and unlock trace events
      scripts/analyse-locks-simpletrace.py: script to analyse lock times
      scripts/replay-dump.py: replay log dumper
      scripts/qemu-gdb/timers.py: new helper to dump timer state

Pavel Dovgalyuk (14):
      block: implement bdrv_snapshot_goto for blkreplay
      blkreplay: create temporary overlay for underlaying devices
      replay: disable default snapshot for record/replay
      replay: fix processing async events
      replay: fixed replay_enable_events
      replay: fix save/load vm for non-empty queue
      replay: added replay log format description
      replay: make safe vmstop at record/replay
      replay: save prior value of the host clock
      icount: fixed saving/restoring of icount warp timers
      cpu-exec: don't overwrite exception_index
      cpu-exec: reset exit flag before calling cpu_exec_nocache
      replay: don't destroy mutex at exit
      replay: check return values of fwrite


 accel/kvm/kvm-all.c                  |    4 
 accel/tcg/cpu-exec.c                 |   99 ++++++-----
 block/blkreplay.c                    |   73 ++++++++
 cpus-common.c                        |   13 +
 cpus.c                               |  134 ++++++++++++---
 docs/replay.txt                      |   91 ++++++++++
 include/qemu/thread.h                |   14 +-
 include/qemu/timer.h                 |   14 ++
 include/sysemu/replay.h              |   19 ++
 migration/savevm.c                   |   13 +
 replay/replay-char.c                 |   21 +-
 replay/replay-events.c               |   30 +--
 replay/replay-internal.c             |   35 +++-
 replay/replay-internal.h             |    9 +
 replay/replay-snapshot.c             |    9 +
 replay/replay-time.c                 |   10 +
 replay/replay.c                      |   42 ++---
 scripts/analyse-locks-simpletrace.py |   99 +++++++++++
 scripts/qemu-gdb.py                  |    4 
 scripts/qemugdb/tcg.py               |   46 +++++
 scripts/qemugdb/timers.py            |   54 ++++++
 scripts/replay-dump.py               |  308 ++++++++++++++++++++++++++++++++++
 stubs/replay.c                       |   16 ++
 target/arm/arm-powerctl.c            |    8 -
 target/i386/hax-all.c                |    2 
 util/main-loop.c                     |   17 +-
 util/qemu-thread-posix.c             |   21 +-
 util/qemu-timer.c                    |   12 +
 util/trace-events                    |    7 -
 vl.c                                 |   12 +
 30 files changed, 1053 insertions(+), 183 deletions(-)
 create mode 100755 scripts/analyse-locks-simpletrace.py
 create mode 100644 scripts/qemugdb/tcg.py
 create mode 100644 scripts/qemugdb/timers.py
 create mode 100755 scripts/replay-dump.py

-- 
Pavel Dovgalyuk

[Qemu-devel] [RFC PATCHv2 01/26] block: implement bdrv_snapshot_goto for blkreplay

[Pavel Dovgalyuk]

From: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>

This patch enables making snapshots with blkreplay used in
block devices.
This function is required to make bdrv_snapshot_goto without
calling .bdrv_open which is not implemented.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>

---
 block/blkreplay.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/blkreplay.c b/block/blkreplay.c
index 61e44a1..82a88f8 100755
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -127,6 +127,12 @@ static int coroutine_fn blkreplay_co_flush(BlockDriverState *bs)
     return ret;
 }
 
+static int blkreplay_snapshot_goto(BlockDriverState *bs,
+                                   const char *snapshot_id)
+{
+    return bdrv_snapshot_goto(bs->file->bs, snapshot_id);
+}
+
 static BlockDriver bdrv_blkreplay = {
     .format_name            = "blkreplay",
     .protocol_name          = "blkreplay",
@@ -143,6 +149,8 @@ static BlockDriver bdrv_blkreplay = {
     .bdrv_co_pwrite_zeroes  = blkreplay_co_pwrite_zeroes,
     .bdrv_co_pdiscard       = blkreplay_co_pdiscard,
     .bdrv_co_flush          = blkreplay_co_flush,
+
+    .bdrv_snapshot_goto     = blkreplay_snapshot_goto,
 };
 
 static void bdrv_blkreplay_init(void)