From patchwork Tue Aug 11 11:00:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 276754 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C776C433E0 for ; Tue, 11 Aug 2020 11:02:23 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 020962075D for ; Tue, 11 Aug 2020 11:02:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 020962075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ispras.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47832 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k5S2w-0003uK-70 for qemu-devel@archiver.kernel.org; Tue, 11 Aug 2020 07:02:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45992) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k5S1e-0002Qn-CE for qemu-devel@nongnu.org; Tue, 11 Aug 2020 07:01:02 -0400 Received: from mail.ispras.ru ([83.149.199.84]:42218) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k5S1b-0003FC-CR for qemu-devel@nongnu.org; Tue, 11 Aug 2020 07:01:02 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id E89154089EF7; Tue, 11 Aug 2020 11:00:53 +0000 (UTC) Subject: [PATCH v2 00/14] Reverse debugging From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Tue, 11 Aug 2020 14:00:53 +0300 Message-ID: <159714365354.18946.2967871683340522027.stgit@pasha-ThinkPad-X280> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Received-SPF: pass client-ip=83.149.199.84; envelope-from=pavel.dovgalyuk@ispras.ru; helo=mail.ispras.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/11 07:00:54 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, wrampazz@redhat.com, pavel.dovgalyuk@ispras.ru, ehabkost@redhat.com, alex.bennee@linaro.org, mtosatti@redhat.com, armbru@redhat.com, mreitz@redhat.com, stefanha@redhat.com, crosa@redhat.com, pbonzini@redhat.com, philmd@redhat.com, zhiwei_liu@c-sky.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.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 - avocado-based acceptance tests for reverse debugging Acceptance tests intended to use the version of avocado framework, that will be released after 25.06.20, because it includes significant fixes of the remote GDB protocol. The patches are available in the repository: https://github.com/ispras/qemu/tree/rr-200811 v2 changes: - rebased to the latest upstream version - fixed replaying of the POLL interrupts after the latest debug changes --- Pavel Dovgaluk (13): replay: provide an accessor for rr filename qcow2: introduce icount field for snapshots migration: introduce icount field for snapshots iotests: update snapshot test for new output format qapi: introduce replay.json for record/replay-related stuff replay: introduce info hmp/qmp command replay: introduce breakpoint at the specified step replay: implement replay-seek command 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 tests/acceptance: add reverse debugging test Pavel Dovgalyuk (1): replay: don't record interrupt poll MAINTAINERS | 2 accel/tcg/cpu-exec.c | 11 + accel/tcg/translator.c | 1 block/qapi.c | 18 +- block/qcow2-snapshot.c | 9 + block/qcow2.h | 3 blockdev.c | 10 + docs/interop/qcow2.txt | 5 + docs/replay.txt | 33 +++ exec.c | 8 + gdbstub.c | 63 ++++++ hmp-commands-info.hx | 11 + hmp-commands.hx | 50 +++++ include/block/snapshot.h | 1 include/monitor/hmp.h | 4 include/sysemu/replay.h | 24 ++ migration/savevm.c | 17 +- qapi/Makefile.objs | 4 qapi/block-core.json | 11 + qapi/misc.json | 18 -- qapi/qapi-schema.json | 1 qapi/replay.json | 121 ++++++++++++ replay/Makefile.objs | 1 replay/replay-debugging.c | 325 +++++++++++++++++++++++++++++++++ replay/replay-events.c | 4 replay/replay-internal.h | 6 - replay/replay.c | 22 ++ softmmu/cpus.c | 19 ++ stubs/replay.c | 15 ++ tests/acceptance/reverse_debugging.py | 203 +++++++++++++++++++++ tests/qemu-iotests/267.out | 48 ++--- 31 files changed, 1002 insertions(+), 66 deletions(-) create mode 100644 qapi/replay.json create mode 100644 replay/replay-debugging.c create mode 100644 tests/acceptance/reverse_debugging.py -- Pavel Dovgalyuk