From mboxrd@z Thu Jan 1 00:00:00 1970 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=-5.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 B43A0C33CB1 for ; Thu, 16 Jan 2020 11:11:54 +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 7F69A2077B for ; Thu, 16 Jan 2020 11:11:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="MJkFscJi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F69A2077B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40124 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is345-0000we-LJ for qemu-devel@archiver.kernel.org; Thu, 16 Jan 2020 06:11:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53110) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is33U-0000Xc-Uh for qemu-devel@nongnu.org; Thu, 16 Jan 2020 06:11:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1is33T-0008Ad-Hs for qemu-devel@nongnu.org; Thu, 16 Jan 2020 06:11:16 -0500 Received: from mail-wm1-x344.google.com ([2a00:1450:4864:20::344]:56108) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1is33T-00089B-88 for qemu-devel@nongnu.org; Thu, 16 Jan 2020 06:11:15 -0500 Received: by mail-wm1-x344.google.com with SMTP id q9so3291170wmj.5 for ; Thu, 16 Jan 2020 03:11:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version:content-transfer-encoding; bh=vwKkwwZvkQ7PyrNEpph6YyojvX4SfdtqoLmrhNzwR5Y=; b=MJkFscJiydEMTMGWHh1pUBB8QyKZQTtmtqKskSyRNeNIT4mA/YJT3qQT++sKq/5GZk YIrern6r+g/bRFaEmMS2ozAZVIKWy7k79yKBWqFE58cLn/1foJ9A/bN1+/cfw8ZT8qij BJknawQ+38naUyJaRGM4pvP2TRvz0igqCX6P/uxCIulN4tIZ4utTbtScgMESFib16QWA qOIuNVMK5YBqE/9FMmsJkN83c5doCUjiydZsU1lRAmLj3a3IaoOUhiTtxGf8oG3L+enl 6w9B+Saz5YUxTftNXW3VwH+jrn3dBl+tM2ze6GNJaCZKA/WEGeQWb7rmBvvUJNoP/Xwl bNMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version:content-transfer-encoding; bh=vwKkwwZvkQ7PyrNEpph6YyojvX4SfdtqoLmrhNzwR5Y=; b=uZV3wv7THyhAMvyECHJFYaq6cU5119rCyV22bOr975EZ6iYNTicbF/EyoW6zQl2HfY eoEaWUuY2ttGTJMUOOt9fTknhaKvNi+QMgMmZv58fyjIKXgHbERLdWa3I9bKo3HZIUnL RXEkbbSZYVpuX3+sewKFCo9DHLlUBWOOrRBOahJjm3f7Tp/aICBigyoG9+CT4G6KtxvI 2PpVSTXYdeioPQC/GL6z4HMuhsrjnikPkxkaWtGgPQDlrI5OZNeMmP7b2k4Lj71+9m/G I2hx6VX0koiY1tUjOCrZD/MTpYM90RaWtDMiiHJU1KU3/99VQFdr46r40URzE5HZUhi1 JJCw== X-Gm-Message-State: APjAAAUr4edTr5a5zOHlEwxFEw9zy6UuvcAQsu+iMHLAUPtilv4tCZao XqsSNjufRkQq3VOKthnQzeymrg== X-Google-Smtp-Source: APXvYqzO6+yw+4wEvS32XyWTUuxwj+l3Y18uqPmZH3wZHP+uOtFQ/6QeFY73JREieQwgpsVfs7RJ6Q== X-Received: by 2002:a7b:c934:: with SMTP id h20mr5412046wml.103.1579173073908; Thu, 16 Jan 2020 03:11:13 -0800 (PST) Received: from zen.linaroharston ([51.148.130.216]) by smtp.gmail.com with ESMTPSA id q3sm3855854wmc.47.2020.01.16.03.11.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2020 03:11:12 -0800 (PST) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id AAF7B1FF87; Thu, 16 Jan 2020 11:11:11 +0000 (GMT) References: <157709434917.12933.4351155074716553976.stgit@pasha-Precision-3630-Tower> User-agent: mu4e 1.3.6; emacs 28.0.50 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Pavel Dovgalyuk Subject: Re: [for-5.0 PATCH 00/11] Support for reverse debugging with GDB In-reply-to: <157709434917.12933.4351155074716553976.stgit@pasha-Precision-3630-Tower> Date: Thu, 16 Jan 2020 11:11:11 +0000 Message-ID: <87o8v3lkq8.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:4864:20::344 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, peter.maydell@linaro.org, pavel.dovgaluk@ispras.ru, pbonzini@redhat.com, crosthwaite.peter@gmail.com, ciro.santilli@gmail.com, jasowang@redhat.com, quintela@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, maria.klimushenkova@ispras.ru, mst@redhat.com, kraxel@redhat.com, boost.lists@gmail.com, thomas.dullien@googlemail.com, dovgaluk@ispras.ru, mreitz@redhat.com, artem.k.pisarenko@gmail.com, dgilbert@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Pavel Dovgalyuk writes: > 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 > > The patches are available in the repository: > https://github.com/ispras/qemu/tree/rr-191223 So I tried with your additional patch. Launching QEMU as: ./aarch64-softmmu//qemu-system-aarch64 -monitor none \ -display none -M virt -cpu max -display none \ -semihosting-config enable=3Don \ -kernel ./tests/tcg/aarch64-softmmu/memory \ -icount shift=3D5,rr=3Dreplay,rrfile=3Drecord.bin \ -s -S -d trace:gdbstub\* And gdb: gdb tests/tcg/aarch64-softmmu/memory \ -ex "target remote localhost:1234" I get the following log: (gdb) x/3i $pc =3D> 0x400037b0 <__start>: adr x0, 0x40003000 0x400037b4 <__start+4>: msr vbar_el1, x0 0x400037b8 <__start+8>: adrp x0, 0x40200000 (gdb) p/x $x0 $1 =3D 0x0 (gdb) si 92 msr vbar_el1, x0 (gdb) p/x $x0 $2 =3D 0x40003000 (gdb) rsi warning: Remote failure reply: E14 Program stopped. __start () at /home/alex.bennee/lsrc/qemu.git/tests/tcg/aarch64/system/bo= ot.S:92 92 msr vbar_el1, x0 (gdb) p/x $x0 $3 =3D 0x40003000 So it doesn't seem to be working. > > --- > > Pavel Dovgaluk (11): > replay: provide an accessor for rr filename > qcow2: introduce icount field for snapshots > migration: introduce icount field for snapshots > 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 > > > MAINTAINERS | 1=20 > accel/tcg/translator.c | 1=20 > block/qapi.c | 18 ++ > block/qcow2-snapshot.c | 9 + > block/qcow2.h | 3=20 > blockdev.c | 10 + > cpus.c | 19 ++- > docs/interop/qcow2.txt | 4 + > docs/replay.txt | 33 +++++ > exec.c | 8 + > gdbstub.c | 64 ++++++++- > hmp-commands-info.hx | 14 ++ > hmp-commands.hx | 53 +++++++ > include/block/snapshot.h | 1=20 > include/monitor/hmp.h | 4 + > include/sysemu/replay.h | 24 +++ > migration/savevm.c | 17 ++ > qapi/Makefile.objs | 2=20 > qapi/block-core.json | 8 + > qapi/block.json | 3=20 > qapi/misc.json | 18 -- > qapi/qapi-schema.json | 1=20 > qapi/replay.json | 121 +++++++++++++++++ > replay/Makefile.objs | 1=20 > replay/replay-debugging.c | 325 +++++++++++++++++++++++++++++++++++++++= ++++++ > replay/replay-internal.h | 6 + > replay/replay.c | 22 +++ > stubs/replay.c | 10 + > 28 files changed, 761 insertions(+), 39 deletions(-) > create mode 100644 qapi/replay.json > create mode 100644 replay/replay-debugging.c --=20 Alex Benn=C3=A9e