From patchwork Tue Dec 18 11:20:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 1015287 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ispras.ru Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 43Jwbn0DQxz9sBZ for ; Tue, 18 Dec 2018 22:22:29 +1100 (AEDT) Received: from localhost ([::1]:53205 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZDSE-0002eP-GP for incoming@patchwork.ozlabs.org; Tue, 18 Dec 2018 06:22:26 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46139) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZDQr-0002Bn-JP for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:21:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gZDQo-0005PF-9T for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:21:01 -0500 Received: from mail.ispras.ru ([83.149.199.45]:55254) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZDQn-0005NN-RL for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:20:58 -0500 Received: from [127.0.1.1] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id EF2F754006A; Tue, 18 Dec 2018 14:20:54 +0300 (MSK) From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Tue, 18 Dec 2018 14:20:57 +0300 Message-ID: <20181218112056.11727.96529.stgit@pasha-VirtualBox> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 83.149.199.45 Subject: [Qemu-devel] [PATCH v8 00/20] Fixing record/replay and adding reverse debugging X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, war2jordan@live.com, pavel.dovgaluk@ispras.ru, pbonzini@redhat.com, crosthwaite.peter@gmail.com, ciro.santilli@gmail.com, jasowang@redhat.com, quintela@redhat.com, armbru@redhat.com, mreitz@redhat.com, alex.bennee@linaro.org, maria.klimushenkova@ispras.ru, mst@redhat.com, kraxel@redhat.com, boost.lists@gmail.com, thomas.dullien@googlemail.com, dovgaluk@ispras.ru, artem.k.pisarenko@gmail.com, dgilbert@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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 - other record/replay fixes The patches are available in the repository: https://github.com/ispras/qemu/tree/rr-181218 v8 changes: - rebased to the new master - added missing fix for prior rr patch - updated 'since' version number in json-related patches v7 changes: - rebased to the new master with upstreamed patches from the series - several improvements in hmp/qmp commands handling (suggested by Markus Armbruster) - fixed record/replay with '-rtc base' option enabled - added document with virtual hardware requirements v6 changes: - rebased to the new version of master - fixed build of linux-user configurations - added new clock for slirp and vnc timers v5 changes: - multiple fixes of record/replay bugs appeared after QEMU core update - changed reverse debugging to 'since 3.1' v4 changes: - changed 'since 2.13' to 'since 3.0' in json (as suggested by Eric Blake) v3 changes: - Fixed PS/2 bug with save/load vm, which caused failures of the replay. - Rebased to the new code base. - Minor fixes. v2 changes: - documented reverse debugging - fixed start vmstate loading in record mode - documented qcow2 changes (as suggested by Eric Blake) - made icount SnapshotInfo field optional (as suggested by Eric Blake) - renamed qmp commands (as suggested by Eric Blake) - minor changes --- Pavel Dovgalyuk (19): block: implement bdrv_snapshot_goto for blkreplay replay: disable default snapshot for record/replay replay: update docs for record/replay with block devices replay: don't drain/flush bdrv queue while RR is working replay: finish record/replay before closing the disks qcow2: introduce icount field for snapshots migration: introduce icount field for snapshots replay: provide and accessor for rr filename replay: introduce info hmp/qmp command replay: introduce breakpoint at the specified step replay: implement replay-seek command to proceed to the desired step replay: refine replay-time module replay: flush rr queue before loading the vmstate gdbstub: add reverse step support in replay mode gdbstub: add reverse continue support in replay mode replay: describe reverse debugging in docs/replay.txt replay: add BH oneshot event for block layer replay: init rtc after enabling the replay replay: document development rules pbonzini@redhat.com (1): replay: add missing fix for internal function accel/tcg/translator.c | 1 block/blkreplay.c | 8 + block/block-backend.c | 5 - block/io.c | 22 +++ block/qapi.c | 18 ++- block/qcow2-snapshot.c | 9 + block/qcow2.h | 2 blockdev.c | 10 + cpus.c | 19 ++- docs/devel/replay.txt | 45 ++++++ docs/interop/qcow2.txt | 4 + docs/replay.txt | 45 ++++++ exec.c | 6 + gdbstub.c | 50 +++++++ hmp-commands-info.hx | 14 ++ hmp-commands.hx | 44 ++++++ hmp.h | 4 + include/block/snapshot.h | 1 include/sysemu/replay.h | 20 +++ migration/savevm.c | 9 + qapi/block-core.json | 7 + qapi/block.json | 3 qapi/misc.json | 82 ++++++++++++ replay/Makefile.objs | 3 replay/replay-debugging.c | 319 +++++++++++++++++++++++++++++++++++++++++++++ replay/replay-events.c | 16 ++ replay/replay-internal.c | 2 replay/replay-internal.h | 7 + replay/replay-time.c | 32 ++--- replay/replay.c | 26 ++++ stubs/Makefile.objs | 1 stubs/replay-user.c | 9 + stubs/replay.c | 10 + vl.c | 21 ++- 34 files changed, 826 insertions(+), 48 deletions(-) create mode 100644 docs/devel/replay.txt create mode 100644 replay/replay-debugging.c create mode 100644 stubs/replay-user.c