From patchwork Mon Sep 14 06:06:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273852 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 C7E92C43461 for ; Mon, 14 Sep 2020 06:08:46 +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 6B2A2206F4 for ; Mon, 14 Sep 2020 06:08:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B2A2206F4 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]:58862 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhfR-0006JI-BK for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:08:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36756) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdM-0002JG-PS for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:36 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44830) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdL-0002Gu-0s for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:36 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 28EB740A2048; Mon, 14 Sep 2020 06:06:32 +0000 (UTC) Subject: [PATCH v4 01/15] replay: don't record interrupt poll From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:06:31 +0300 Message-ID: <160006359182.31457.6752163542475006502.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" 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 Reviewed-by: Alex Bennée --- 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 66d38f9d85..c065b4cc77 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -429,8 +429,7 @@ 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); @@ -526,6 +525,20 @@ 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) { @@ -587,7 +600,9 @@ 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 From patchwork Mon Sep 14 06:06:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273850 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 B2C66C433E2 for ; Mon, 14 Sep 2020 06:10:13 +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 4AB45206F4 for ; Mon, 14 Sep 2020 06:10:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4AB45206F4 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]:38940 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhgq-0001Bt-EX for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:10:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36776) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdR-0002Oa-N5 for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:41 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44846) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdQ-0002H9-2P for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:41 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id EC24840A2055; Mon, 14 Sep 2020 06:06:37 +0000 (UTC) Subject: [PATCH v4 02/15] replay: provide an accessor for rr filename From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:06:37 +0300 Message-ID: <160006359759.31457.13985126457254477309.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Reviewed-by: Alex Bennée --- 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; +} From patchwork Mon Sep 14 06:06:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273853 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 21245C43461 for ; Mon, 14 Sep 2020 06:07:39 +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 AF083206F4 for ; Mon, 14 Sep 2020 06:07:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF083206F4 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]:52602 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHheL-0003lj-LQ for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:07:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36798) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdX-0002V4-F3 for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:47 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44860) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdV-0002IC-NK for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:47 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id B14A740D3BFF; Mon, 14 Sep 2020 06:06:43 +0000 (UTC) Subject: [PATCH v4 03/15] qcow2: introduce icount field for snapshots From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:06:43 +0300 Message-ID: <160006360339.31457.18121116124303431004.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Acked-by: Kevin Wolf --- block/qcow2-snapshot.c | 7 +++++++ block/qcow2.h | 3 +++ docs/interop/qcow2.txt | 5 +++++ 3 files changed, 15 insertions(+) diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 2756b37d24..d14e7be1aa 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 065ec3df0b..c39a1e1265 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -200,6 +200,7 @@ typedef struct QEMU_PACKED QCowSnapshotHeader { typedef struct QEMU_PACKED QCowSnapshotExtraData { uint64_t vm_state_size_large; uint64_t disk_size; + uint64_t icount; } QCowSnapshotExtraData; @@ -213,6 +214,8 @@ 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. From patchwork Mon Sep 14 06:06:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305522 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 98FB2C433E2 for ; Mon, 14 Sep 2020 06:07:49 +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 3B230206F4 for ; Mon, 14 Sep 2020 06:07:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B230206F4 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]:53698 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHheW-0004E1-6b for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:07:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36820) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhde-0002fp-2I for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:54 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44876) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdb-0002Jw-CS for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:53 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 7D7E040D3BFF; Mon, 14 Sep 2020 06:06:49 +0000 (UTC) Subject: [PATCH v4 04/15] migration: introduce icount field for snapshots From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:06:49 +0300 Message-ID: <160006360913.31457.10355303487606253928.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" 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 Acked-by: Markus Armbruster Acked-by: Kevin Wolf --- v4 changes: - squashed format update with test output update --- 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/267.out | 48 ++++++++++++++++++++++---------------------- 8 files changed, 69 insertions(+), 30 deletions(-) diff --git a/block/qapi.c b/block/qapi.c index f423ece98c..1086ee0c76 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("%-10s%-18s%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 d14e7be1aa..4b127ea6af 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 7f2561081e..ac1c803a7f 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 304d98ff78..74378f8ebd 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 2d94873ca0..e25aff4e4b 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: @@ -5527,7 +5532,8 @@ # "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/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 From patchwork Mon Sep 14 06:06:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305519 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 45701C43461 for ; Mon, 14 Sep 2020 06:11:56 +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 EEDCB206F4 for ; Mon, 14 Sep 2020 06:11:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEDCB206F4 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]:47096 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhiV-0004YZ-3Z for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:11:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36848) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdj-0002qU-8w for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:59 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44900) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdh-0002MK-BU for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:06:58 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 522B940D3BFF; Mon, 14 Sep 2020 06:06:55 +0000 (UTC) Subject: [PATCH v4 05/15] qapi: introduce replay.json for record/replay-related stuff From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:06:55 +0300 Message-ID: <160006361496.31457.7759589427571616515.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk This patch adds replay.json file. It will be used for adding record/replay-related data structures and commands. Signed-off-by: Pavel Dovgalyuk Reviewed-by: Markus Armbruster Reviewed-by: Alex Bennée --- 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 d817ee6c6f..7724fd3f8a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2661,6 +2661,7 @@ 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 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 2b2872a41d..f4fd514379 100644 --- a/qapi/meson.build +++ b/qapi/meson.build @@ -36,6 +36,7 @@ qapi_all_modules = [ 'qdev', 'qom', 'rdma', + 'replay', 'rocker', 'run-state', 'sockets', diff --git a/qapi/misc.json b/qapi/misc.json index 8cf6ebe67c..b194ec4a30 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -1556,24 +1556,6 @@ { 'event': 'ACPI_DEVICE_OST', 'data': { 'info': 'ACPIOSTInfo' } } -## -# @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 f03ff91ceb..2604fcf6ec 100644 --- a/qapi/qapi-schema.json +++ b/qapi/qapi-schema.json @@ -82,6 +82,7 @@ { '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' ] } From patchwork Mon Sep 14 06:07:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305518 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 66005C43461 for ; Mon, 14 Sep 2020 06:13:19 +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 004DE206F4 for ; Mon, 14 Sep 2020 06:13:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 004DE206F4 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]:53890 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhjq-0007G8-5t for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:13:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36876) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdp-00033U-1t for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:05 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44916) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdn-0002MY-1C for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:04 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 1D15C40D3BFF; Mon, 14 Sep 2020 06:07:01 +0000 (UTC) Subject: [PATCH v4 06/15] replay: introduce info hmp/qmp command From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:00 +0300 Message-ID: <160006362075.31457.16304630329752865389.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Acked-by: Dr. David Alan Gilbert Acked-by: Markus Armbruster --- 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 c986cfd28b..a790589b9e 100644 --- a/include/monitor/hmp.h +++ b/include/monitor/hmp.h @@ -130,5 +130,6 @@ 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 e25aff4e4b..26d098ea0b 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; +} From patchwork Mon Sep 14 06:07:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305521 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 DC174C2D0E3 for ; Mon, 14 Sep 2020 06:09:07 +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 6F171206F4 for ; Mon, 14 Sep 2020 06:09:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F171206F4 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]:60824 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhfm-00075I-DL for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:09:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36920) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhdv-0003Is-6y for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:11 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44934) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhds-0002NK-Ue for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:10 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id D9CC740D3BFF; Mon, 14 Sep 2020 06:07:06 +0000 (UTC) Subject: [PATCH v4 07/15] replay: introduce breakpoint at the specified step From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:06 +0300 Message-ID: <160006362654.31457.5024270491146336329.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Acked-by: Markus Armbruster --- 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 60f395c276..e8ce385879 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -1819,6 +1819,38 @@ 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 a790589b9e..21849bdda5 100644 --- a/include/monitor/hmp.h +++ b/include/monitor/hmp.h @@ -131,5 +131,7 @@ 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)); + } } } } From patchwork Mon Sep 14 06:07:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273847 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 42556C43461 for ; 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Mon, 14 Sep 2020 02:07:16 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id AA7B240A2048; Mon, 14 Sep 2020 06:07:12 +0000 (UTC) Subject: [PATCH v4 08/15] replay: implement replay-seek command From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:12 +0300 Message-ID: <160006363232.31457.2876139037250542555.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Acked-by: Markus Armbruster --- 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 e8ce385879..262bc986b9 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -1851,6 +1851,24 @@ 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 21849bdda5..655eb81a4c 100644 --- a/include/monitor/hmp.h +++ b/include/monitor/hmp.h @@ -133,5 +133,6 @@ 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; + } +} From patchwork Mon Sep 14 06:07:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305517 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 38110C43461 for ; Mon, 14 Sep 2020 06:15:49 +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 D638A206DC for ; Mon, 14 Sep 2020 06:15:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D638A206DC 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]:32828 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhmF-0001ni-Vo for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:15:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36996) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhe6-0003oK-Gu for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:22 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44968) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhe4-0002Pw-Hd for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:22 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 82A2440D3BFF; Mon, 14 Sep 2020 06:07:18 +0000 (UTC) Subject: [PATCH v4 09/15] replay: flush rr queue before loading the vmstate From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:18 +0300 Message-ID: <160006363811.31457.8237170735033134042.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Reviewed-by: Alex Bennée --- 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 74378f8ebd..7905aab053 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2880,12 +2880,6 @@ 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", @@ -2919,6 +2913,12 @@ 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 */ From patchwork Mon Sep 14 06:07:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273851 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 C1CF9C43461 for ; Mon, 14 Sep 2020 06:09:18 +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 7BFAE206F4 for ; Mon, 14 Sep 2020 06:09:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BFAE206F4 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]:33766 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhfx-0007YV-Fp for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:09:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37052) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHheD-0003yT-1a for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:29 -0400 Received: from mail.ispras.ru ([83.149.199.84]:44978) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHheA-0002QV-Bn for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:28 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 562E840D3BFF; Mon, 14 Sep 2020 06:07:24 +0000 (UTC) Subject: [PATCH v4 10/15] gdbstub: add reverse step support in replay mode From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:24 +0300 Message-ID: <160006364393.31457.10487097692089464911.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 Reviewed-by: Alex Bennée --- 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 | 33 +++++++++++++++++++++++++++ softmmu/cpus.c | 14 +++++++++-- stubs/replay.c | 5 ++++ 7 files changed, 121 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 e34b602bdf..65983738f2 100644 --- a/exec.c +++ b/exec.c @@ -2751,6 +2751,13 @@ 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..f7594a88cd 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 +219,29 @@ 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 e3b98065c9..dc72f93bc0 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; +} From patchwork Mon Sep 14 06:07:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273848 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 6A6B4C433E2 for ; Mon, 14 Sep 2020 06:12:31 +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 104BC207BB for ; 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Mon, 14 Sep 2020 06:07:30 +0000 (UTC) Subject: [PATCH v4 11/15] gdbstub: add reverse continue support in replay mode From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:29 +0300 Message-ID: <160006364979.31457.720139270521139007.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 --- exec.c | 1 + gdbstub.c | 10 ++++++ include/sysemu/replay.h | 8 +++++ replay/replay-debugging.c | 71 +++++++++++++++++++++++++++++++++++++++++++++ softmmu/cpus.c | 5 +++ stubs/replay.c | 5 +++ 6 files changed, 99 insertions(+), 1 deletion(-) diff --git a/exec.c b/exec.c index 65983738f2..4333dde185 100644 --- a/exec.c +++ b/exec.c @@ -2756,6 +2756,7 @@ 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 f7594a88cd..d02d4e0766 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) { @@ -245,3 +247,72 @@ 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 dc72f93bc0..756f268993 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; +} From patchwork Mon Sep 14 06:07:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305520 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 53A11C43461 for ; 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Mon, 14 Sep 2020 02:07:39 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id EFB4940D3BFF; Mon, 14 Sep 2020 06:07:35 +0000 (UTC) Subject: [PATCH v4 12/15] replay: describe reverse debugging in docs/replay.txt From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:35 +0300 Message-ID: <160006365557.31457.13435872247215044498.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk This patch updates the documentation and describes usage of the reverse debugging in QEMU+GDB. Signed-off-by: Pavel Dovgalyuk Reviewed-by: Alex Bennée --- 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 ----------------- From patchwork Mon Sep 14 06:07:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273846 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 88684C43461 for ; Mon, 14 Sep 2020 06:17:31 +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 D1DC5208DB for ; Mon, 14 Sep 2020 06:17:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1DC5208DB 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]:36882 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhnt-0003ah-Sv for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:17:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37162) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHheW-0004jo-HN for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:48 -0400 Received: from mail.ispras.ru ([83.149.199.84]:45018) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHheR-0002RZ-Pl for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:48 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id C6D5440D3BFF; Mon, 14 Sep 2020 06:07:41 +0000 (UTC) Subject: [PATCH v4 13/15] docs: convert replay.txt to rst From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:41 +0300 Message-ID: <160006366140.31457.12864422435316394143.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" This patch converts record/replay documentation into rst format. Signed-off-by: Pavel Dovgalyuk --- docs/replay.txt | 410 ------------------------------------------------ docs/system/index.rst | 1 docs/system/replay.rst | 410 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 411 insertions(+), 410 deletions(-) delete mode 100644 docs/replay.txt create mode 100644 docs/system/replay.rst diff --git a/docs/replay.txt b/docs/replay.txt deleted file mode 100644 index 39fe5e9740..0000000000 --- a/docs/replay.txt +++ /dev/null @@ -1,410 +0,0 @@ -Copyright (c) 2010-2015 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. - -Record/replay -------------- - -Record/replay functions are used for the deterministic replay of qemu execution. -Execution recording writes a non-deterministic events log, which can be later -used for replaying the execution anywhere and for unlimited number of times. -It also supports checkpointing for faster rewind to the specific replay moment. -Execution replaying reads the log and replays all non-deterministic events -including external input, hardware clocks, and interrupts. - -Deterministic replay has the following features: - * Deterministically replays whole system execution and all contents of - the memory, state of the hardware devices, clocks, and screen of the VM. - * Writes execution log into the file for later replaying for multiple times - on different machines. - * Supports i386, x86_64, and Arm hardware platforms. - * Performs deterministic replay of all operations with keyboard and mouse - input devices. - -Usage of the record/replay: - * First, record the execution with the following command line: - qemu-system-i386 \ - -icount shift=7,rr=record,rrfile=replay.bin \ - -drive file=disk.qcow2,if=none,snapshot,id=img-direct \ - -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \ - -device ide-hd,drive=img-blkreplay \ - -netdev user,id=net1 -device rtl8139,netdev=net1 \ - -object filter-replay,id=replay,netdev=net1 - * After recording, you can replay it by using another command line: - qemu-system-i386 \ - -icount shift=7,rr=replay,rrfile=replay.bin \ - -drive file=disk.qcow2,if=none,snapshot,id=img-direct \ - -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \ - -device ide-hd,drive=img-blkreplay \ - -netdev user,id=net1 -device rtl8139,netdev=net1 \ - -object filter-replay,id=replay,netdev=net1 - The only difference with recording is changing the rr option - from record to replay. - * Block device images are not actually changed in the recording mode, - because all of the changes are written to the temporary overlay file. - This behavior is enabled by using blkreplay driver. It should be used - for every enabled block device, as described in 'Block devices' section. - * '-net none' option should be specified when network is not used, - because QEMU adds network card by default. When network is needed, - it should be configured explicitly with replay filter, as described - in 'Network devices' section. - * Interaction with audio devices and serial ports are recorded and replayed - automatically when such devices are enabled. - -Academic papers with description of deterministic replay implementation: -http://www.computer.org/csdl/proceedings/csmr/2012/4666/00/4666a553-abs.html -http://dl.acm.org/citation.cfm?id=2786805.2803179 - -Modifications of qemu include: - * wrappers for clock and time functions to save their return values in the log - * saving different asynchronous events (e.g. system shutdown) into the log - * synchronization of the bottom halves execution - * synchronization of the threads from thread pool - * recording/replaying user input (mouse, keyboard, and microphone) - * adding internal checkpoints for cpu and io synchronization - * network filter for recording and replaying the packets - * block driver for making block layer deterministic - * serial port input record and replay - * recording of random numbers obtained from the external sources - -Locking and thread synchronisation ----------------------------------- - -Previously the synchronisation of the main thread and the vCPU thread -was ensured by the holding of the BQL. However the trend has been to -reduce the time the BQL was held across the system including under TCG -system emulation. As it is important that batches of events are kept -in sequence (e.g. expiring timers and checkpoints in the main thread -while instruction checkpoints are written by the vCPU thread) we need -another lock to keep things in lock-step. This role is now handled by -the replay_mutex_lock. It used to be held only for each event being -written but now it is held for a whole execution period. This results -in a deterministic ping-pong between the two main threads. - -As the BQL is now a finer grained lock than the replay_lock it is almost -certainly a bug, and a source of deadlocks, to take the -replay_mutex_lock while the BQL is held. This is enforced by an assert. -While the unlocks are usually in the reverse order, this is not -necessary; you can drop the replay_lock while holding the BQL, without -doing a more complicated unlock_iothread/replay_unlock/lock_iothread -sequence. - -Non-deterministic events ------------------------- - -Our record/replay system is based on saving and replaying non-deterministic -events (e.g. keyboard input) and simulating deterministic ones (e.g. reading -from HDD or memory of the VM). Saving only non-deterministic events makes -log file smaller and simulation faster. - -The following non-deterministic data from peripheral devices is saved into -the log: mouse and keyboard input, network packets, audio controller input, -serial port input, and hardware clocks (they are non-deterministic -too, because their values are taken from the host machine). Inputs from -simulated hardware, memory of VM, software interrupts, and execution of -instructions are not saved into the log, because they are deterministic and -can be replayed by simulating the behavior of virtual machine starting from -initial state. - -We had to solve three tasks to implement deterministic replay: recording -non-deterministic events, replaying non-deterministic events, and checking -that there is no divergence between record and replay modes. - -We changed several parts of QEMU to make event log recording and replaying. -Devices' models that have non-deterministic input from external devices were -changed to write every external event into the execution log immediately. -E.g. network packets are written into the log when they arrive into the virtual -network adapter. - -All non-deterministic events are coming from these devices. But to -replay them we need to know at which moments they occur. We specify -these moments by counting the number of instructions executed between -every pair of consecutive events. - -Instruction counting --------------------- - -QEMU should work in icount mode to use record/replay feature. icount was -designed to allow deterministic execution in absence of external inputs -of the virtual machine. We also use icount to control the occurrence of the -non-deterministic events. The number of instructions elapsed from the last event -is written to the log while recording the execution. In replay mode we -can predict when to inject that event using the instruction counter. - -Timers ------- - -Timers are used to execute callbacks from different subsystems of QEMU -at the specified moments of time. There are several kinds of timers: - * Real time clock. Based on host time and used only for callbacks that - do not change the virtual machine state. For this reason real time - clock and timers does not affect deterministic replay at all. - * Virtual clock. These timers run only during the emulation. In icount - mode virtual clock value is calculated using executed instructions counter. - That is why it is completely deterministic and does not have to be recorded. - * Host clock. This clock is used by device models that simulate real time - sources (e.g. real time clock chip). Host clock is the one of the sources - of non-determinism. Host clock read operations should be logged to - make the execution deterministic. - * Virtual real time clock. This clock is similar to real time clock but - it is used only for increasing virtual clock while virtual machine is - sleeping. Due to its nature it is also non-deterministic as the host clock - and has to be logged too. - -Checkpoints ------------ - -Replaying of the execution of virtual machine is bound by sources of -non-determinism. These are inputs from clock and peripheral devices, -and QEMU thread scheduling. Thread scheduling affect on processing events -from timers, asynchronous input-output, and bottom halves. - -Invocations of timers are coupled with clock reads and changing the state -of the virtual machine. Reads produce non-deterministic data taken from -host clock. And VM state changes should preserve their order. Their relative -order in replay mode must replicate the order of callbacks in record mode. -To preserve this order we use checkpoints. When a specific clock is processed -in record mode we save to the log special "checkpoint" event. -Checkpoints here do not refer to virtual machine snapshots. They are just -record/replay events used for synchronization. - -QEMU in replay mode will try to invoke timers processing in random moment -of time. That's why we do not process a group of timers until the checkpoint -event will be read from the log. Such an event allows synchronizing CPU -execution and timer events. - -Two other checkpoints govern the "warping" of the virtual clock. -While the virtual machine is idle, the virtual clock increments at -1 ns per *real time* nanosecond. This is done by setting up a timer -(called the warp timer) on the virtual real time clock, so that the -timer fires at the next deadline of the virtual clock; the virtual clock -is then incremented (which is called "warping" the virtual clock) as -soon as the timer fires or the CPUs need to go out of the idle state. -Two functions are used for this purpose; because these actions change -virtual machine state and must be deterministic, each of them creates a -checkpoint. qemu_start_warp_timer checks if the CPUs are idle and if so -starts accounting real time to virtual clock. qemu_account_warp_timer -is called when the CPUs get an interrupt or when the warp timer fires, -and it warps the virtual clock by the amount of real time that has passed -since qemu_start_warp_timer. - -Bottom halves -------------- - -Disk I/O events are completely deterministic in our model, because -in both record and replay modes we start virtual machine from the same -disk state. But callbacks that virtual disk controller uses for reading and -writing the disk may occur at different moments of time in record and replay -modes. - -Reading and writing requests are created by CPU thread of QEMU. Later these -requests proceed to block layer which creates "bottom halves". Bottom -halves consist of callback and its parameters. They are processed when -main loop locks the global mutex. These locks are not synchronized with -replaying process because main loop also processes the events that do not -affect the virtual machine state (like user interaction with monitor). - -That is why we had to implement saving and replaying bottom halves callbacks -synchronously to the CPU execution. When the callback is about to execute -it is added to the queue in the replay module. This queue is written to the -log when its callbacks are executed. In replay mode callbacks are not processed -until the corresponding event is read from the events log file. - -Sometimes the block layer uses asynchronous callbacks for its internal purposes -(like reading or writing VM snapshots or disk image cluster tables). In this -case bottom halves are not marked as "replayable" and do not saved -into the log. - -Block devices -------------- - -Block devices record/replay module intercepts calls of -bdrv coroutine functions at the top of block drivers stack. -To record and replay block operations the drive must be configured -as following: - -drive file=disk.qcow2,if=none,snapshot,id=img-direct - -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay - -device ide-hd,drive=img-blkreplay - -blkreplay driver should be inserted between disk image and virtual driver -controller. Therefore all disk requests may be recorded and replayed. - -All block completion operations are added to the queue in the coroutines. -Queue is flushed at checkpoints and information about processed requests -is recorded to the log. In replay phase the queue is matched with -events read from the log. Therefore block devices requests are processed -deterministically. - -Snapshotting ------------- - -New VM snapshots may be created in replay mode. They can be used later -to recover the desired VM state. All VM states created in replay mode -are associated with the moment of time in the replay scenario. -After recovering the VM state replay will start from that position. - -Default starting snapshot name may be specified with icount field -rrsnapshot as follows: - -icount shift=7,rr=record,rrfile=replay.bin,rrsnapshot=snapshot_name - -This snapshot is created at start of recording and restored at start -of replaying. It also can be loaded while replaying to roll back -the execution. - -'snapshot' flag of the disk image must be removed to save the snapshots -in the overlay (or original image) instead of using the temporary overlay. - -drive file=disk.ovl,if=none,id=img-direct - -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay - -device ide-hd,drive=img-blkreplay - -Use QEMU monitor to create additional snapshots. 'savevm ' command -created the snapshot and 'loadvm ' restores it. To prevent corruption -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 ---------------- - -Record and replay for network interactions is performed with the network filter. -Each backend must have its own instance of the replay filter as follows: - -netdev user,id=net1 -device rtl8139,netdev=net1 - -object filter-replay,id=replay,netdev=net1 - -Replay network filter is used to record and replay network packets. While -recording the virtual machine this filter puts all packets coming from -the outer world into the log. In replay mode packets from the log are -injected into the network device. All interactions with network backend -in replay mode are disabled. - -Audio devices -------------- - -Audio data is recorded and replay automatically. The command line for recording -and replaying must contain identical specifications of audio hardware, e.g.: - -soundhw ac97 - -Serial ports ------------- - -Serial ports input is recorded and replay automatically. The command lines -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 ------------------ - -Record/replay log consists of the header and the sequence of execution -events. The header includes 4-byte replay version id and 8-byte reserved -field. Version is updated every time replay log format changes to prevent -using replay log created by another build of qemu. - -The sequence of the events describes virtual machine state changes. -It includes all non-deterministic inputs of VM, synchronization marks and -instruction counts used to correctly inject inputs at replay. - -Synchronization marks (checkpoints) are used for synchronizing qemu threads -that perform operations with virtual hardware. These operations may change -system's state (e.g., change some register or generate interrupt) and -therefore should execute synchronously with CPU thread. - -Every event in the log includes 1-byte event id and optional arguments. -When argument is an array, it is stored as 4-byte array length -and corresponding number of bytes with data. -Here is the list of events that are written into the log: - - - EVENT_INSTRUCTION. Instructions executed since last event. - Argument: 4-byte number of executed instructions. - - EVENT_INTERRUPT. Used to synchronize interrupt processing. - - EVENT_EXCEPTION. Used to synchronize exception handling. - - EVENT_ASYNC. This is a group of events. They are always processed - together with checkpoints. When such an event is generated, it is - stored in the queue and processed only when checkpoint occurs. - Every such event is followed by 1-byte checkpoint id and 1-byte - async event id from the following list: - - REPLAY_ASYNC_EVENT_BH. Bottom-half callback. This event synchronizes - callbacks that affect virtual machine state, but normally called - asynchronously. - Argument: 8-byte operation id. - - REPLAY_ASYNC_EVENT_INPUT. Input device event. Contains - parameters of keyboard and mouse input operations - (key press/release, mouse pointer movement). - Arguments: 9-16 bytes depending of input event. - - REPLAY_ASYNC_EVENT_INPUT_SYNC. Internal input synchronization event. - - REPLAY_ASYNC_EVENT_CHAR_READ. Character (e.g., serial port) device input - initiated by the sender. - Arguments: 1-byte character device id. - Array with bytes were read. - - REPLAY_ASYNC_EVENT_BLOCK. Block device operation. Used to synchronize - operations with disk and flash drives with CPU. - Argument: 8-byte operation id. - - REPLAY_ASYNC_EVENT_NET. Incoming network packet. - Arguments: 1-byte network adapter id. - 4-byte packet flags. - Array with packet bytes. - - EVENT_SHUTDOWN. Occurs when user sends shutdown event to qemu, - e.g., by closing the window. - - EVENT_CHAR_WRITE. Used to synchronize character output operations. - Arguments: 4-byte output function return value. - 4-byte offset in the output array. - - EVENT_CHAR_READ_ALL. Used to synchronize character input operations, - initiated by qemu. - Argument: Array with bytes that were read. - - EVENT_CHAR_READ_ALL_ERROR. Unsuccessful character input operation, - initiated by qemu. - Argument: 4-byte error code. - - EVENT_CLOCK + clock_id. Group of events for host clock read operations. - Argument: 8-byte clock value. - - EVENT_CHECKPOINT + checkpoint_id. Checkpoint for synchronization of - CPU, internal threads, and asynchronous input events. May be followed - by one or more EVENT_ASYNC events. - - EVENT_END. Last event in the log. diff --git a/docs/system/index.rst b/docs/system/index.rst index c0f685b818..39fe8177f5 100644 --- a/docs/system/index.rst +++ b/docs/system/index.rst @@ -27,6 +27,7 @@ Contents: vnc-security tls gdb + replay managed-startup targets security diff --git a/docs/system/replay.rst b/docs/system/replay.rst new file mode 100644 index 0000000000..d6395ab72a --- /dev/null +++ b/docs/system/replay.rst @@ -0,0 +1,410 @@ +Copyright (c) 2010-2015 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. + +Record/replay +============= + +Record/replay functions are used for the deterministic replay of qemu execution. +Execution recording writes a non-deterministic events log, which can be later +used for replaying the execution anywhere and for unlimited number of times. +It also supports checkpointing for faster rewind to the specific replay moment. +Execution replaying reads the log and replays all non-deterministic events +including external input, hardware clocks, and interrupts. + +Deterministic replay has the following features: + * Deterministically replays whole system execution and all contents of + the memory, state of the hardware devices, clocks, and screen of the VM. + * Writes execution log into the file for later replaying for multiple times + on different machines. + * Supports i386, x86_64, and Arm hardware platforms. + * Performs deterministic replay of all operations with keyboard and mouse + input devices. + +Usage of the record/replay: + * First, record the execution with the following command line: + qemu-system-i386 \ + -icount shift=7,rr=record,rrfile=replay.bin \ + -drive file=disk.qcow2,if=none,snapshot,id=img-direct \ + -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \ + -device ide-hd,drive=img-blkreplay \ + -netdev user,id=net1 -device rtl8139,netdev=net1 \ + -object filter-replay,id=replay,netdev=net1 + * After recording, you can replay it by using another command line: + qemu-system-i386 \ + -icount shift=7,rr=replay,rrfile=replay.bin \ + -drive file=disk.qcow2,if=none,snapshot,id=img-direct \ + -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \ + -device ide-hd,drive=img-blkreplay \ + -netdev user,id=net1 -device rtl8139,netdev=net1 \ + -object filter-replay,id=replay,netdev=net1 + The only difference with recording is changing the rr option + from record to replay. + * Block device images are not actually changed in the recording mode, + because all of the changes are written to the temporary overlay file. + This behavior is enabled by using blkreplay driver. It should be used + for every enabled block device, as described in 'Block devices' section. + * '-net none' option should be specified when network is not used, + because QEMU adds network card by default. When network is needed, + it should be configured explicitly with replay filter, as described + in 'Network devices' section. + * Interaction with audio devices and serial ports are recorded and replayed + automatically when such devices are enabled. + +Academic papers with description of deterministic replay implementation: +http://www.computer.org/csdl/proceedings/csmr/2012/4666/00/4666a553-abs.html +http://dl.acm.org/citation.cfm?id=2786805.2803179 + +Modifications of qemu include: + * wrappers for clock and time functions to save their return values in the log + * saving different asynchronous events (e.g. system shutdown) into the log + * synchronization of the bottom halves execution + * synchronization of the threads from thread pool + * recording/replaying user input (mouse, keyboard, and microphone) + * adding internal checkpoints for cpu and io synchronization + * network filter for recording and replaying the packets + * block driver for making block layer deterministic + * serial port input record and replay + * recording of random numbers obtained from the external sources + +Locking and thread synchronisation +---------------------------------- + +Previously the synchronisation of the main thread and the vCPU thread +was ensured by the holding of the BQL. However the trend has been to +reduce the time the BQL was held across the system including under TCG +system emulation. As it is important that batches of events are kept +in sequence (e.g. expiring timers and checkpoints in the main thread +while instruction checkpoints are written by the vCPU thread) we need +another lock to keep things in lock-step. This role is now handled by +the replay_mutex_lock. It used to be held only for each event being +written but now it is held for a whole execution period. This results +in a deterministic ping-pong between the two main threads. + +As the BQL is now a finer grained lock than the replay_lock it is almost +certainly a bug, and a source of deadlocks, to take the +replay_mutex_lock while the BQL is held. This is enforced by an assert. +While the unlocks are usually in the reverse order, this is not +necessary; you can drop the replay_lock while holding the BQL, without +doing a more complicated unlock_iothread/replay_unlock/lock_iothread +sequence. + +Non-deterministic events +------------------------ + +Our record/replay system is based on saving and replaying non-deterministic +events (e.g. keyboard input) and simulating deterministic ones (e.g. reading +from HDD or memory of the VM). Saving only non-deterministic events makes +log file smaller and simulation faster. + +The following non-deterministic data from peripheral devices is saved into +the log: mouse and keyboard input, network packets, audio controller input, +serial port input, and hardware clocks (they are non-deterministic +too, because their values are taken from the host machine). Inputs from +simulated hardware, memory of VM, software interrupts, and execution of +instructions are not saved into the log, because they are deterministic and +can be replayed by simulating the behavior of virtual machine starting from +initial state. + +We had to solve three tasks to implement deterministic replay: recording +non-deterministic events, replaying non-deterministic events, and checking +that there is no divergence between record and replay modes. + +We changed several parts of QEMU to make event log recording and replaying. +Devices' models that have non-deterministic input from external devices were +changed to write every external event into the execution log immediately. +E.g. network packets are written into the log when they arrive into the virtual +network adapter. + +All non-deterministic events are coming from these devices. But to +replay them we need to know at which moments they occur. We specify +these moments by counting the number of instructions executed between +every pair of consecutive events. + +Instruction counting +-------------------- + +QEMU should work in icount mode to use record/replay feature. icount was +designed to allow deterministic execution in absence of external inputs +of the virtual machine. We also use icount to control the occurrence of the +non-deterministic events. The number of instructions elapsed from the last event +is written to the log while recording the execution. In replay mode we +can predict when to inject that event using the instruction counter. + +Timers +------ + +Timers are used to execute callbacks from different subsystems of QEMU +at the specified moments of time. There are several kinds of timers: + * Real time clock. Based on host time and used only for callbacks that + do not change the virtual machine state. For this reason real time + clock and timers does not affect deterministic replay at all. + * Virtual clock. These timers run only during the emulation. In icount + mode virtual clock value is calculated using executed instructions counter. + That is why it is completely deterministic and does not have to be recorded. + * Host clock. This clock is used by device models that simulate real time + sources (e.g. real time clock chip). Host clock is the one of the sources + of non-determinism. Host clock read operations should be logged to + make the execution deterministic. + * Virtual real time clock. This clock is similar to real time clock but + it is used only for increasing virtual clock while virtual machine is + sleeping. Due to its nature it is also non-deterministic as the host clock + and has to be logged too. + +Checkpoints +----------- + +Replaying of the execution of virtual machine is bound by sources of +non-determinism. These are inputs from clock and peripheral devices, +and QEMU thread scheduling. Thread scheduling affect on processing events +from timers, asynchronous input-output, and bottom halves. + +Invocations of timers are coupled with clock reads and changing the state +of the virtual machine. Reads produce non-deterministic data taken from +host clock. And VM state changes should preserve their order. Their relative +order in replay mode must replicate the order of callbacks in record mode. +To preserve this order we use checkpoints. When a specific clock is processed +in record mode we save to the log special "checkpoint" event. +Checkpoints here do not refer to virtual machine snapshots. They are just +record/replay events used for synchronization. + +QEMU in replay mode will try to invoke timers processing in random moment +of time. That's why we do not process a group of timers until the checkpoint +event will be read from the log. Such an event allows synchronizing CPU +execution and timer events. + +Two other checkpoints govern the "warping" of the virtual clock. +While the virtual machine is idle, the virtual clock increments at +1 ns per *real time* nanosecond. This is done by setting up a timer +(called the warp timer) on the virtual real time clock, so that the +timer fires at the next deadline of the virtual clock; the virtual clock +is then incremented (which is called "warping" the virtual clock) as +soon as the timer fires or the CPUs need to go out of the idle state. +Two functions are used for this purpose; because these actions change +virtual machine state and must be deterministic, each of them creates a +checkpoint. qemu_start_warp_timer checks if the CPUs are idle and if so +starts accounting real time to virtual clock. qemu_account_warp_timer +is called when the CPUs get an interrupt or when the warp timer fires, +and it warps the virtual clock by the amount of real time that has passed +since qemu_start_warp_timer. + +Bottom halves +------------- + +Disk I/O events are completely deterministic in our model, because +in both record and replay modes we start virtual machine from the same +disk state. But callbacks that virtual disk controller uses for reading and +writing the disk may occur at different moments of time in record and replay +modes. + +Reading and writing requests are created by CPU thread of QEMU. Later these +requests proceed to block layer which creates "bottom halves". Bottom +halves consist of callback and its parameters. They are processed when +main loop locks the global mutex. These locks are not synchronized with +replaying process because main loop also processes the events that do not +affect the virtual machine state (like user interaction with monitor). + +That is why we had to implement saving and replaying bottom halves callbacks +synchronously to the CPU execution. When the callback is about to execute +it is added to the queue in the replay module. This queue is written to the +log when its callbacks are executed. In replay mode callbacks are not processed +until the corresponding event is read from the events log file. + +Sometimes the block layer uses asynchronous callbacks for its internal purposes +(like reading or writing VM snapshots or disk image cluster tables). In this +case bottom halves are not marked as "replayable" and do not saved +into the log. + +Block devices +------------- + +Block devices record/replay module intercepts calls of +bdrv coroutine functions at the top of block drivers stack. +To record and replay block operations the drive must be configured +as following: + -drive file=disk.qcow2,if=none,snapshot,id=img-direct + -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay + -device ide-hd,drive=img-blkreplay + +blkreplay driver should be inserted between disk image and virtual driver +controller. Therefore all disk requests may be recorded and replayed. + +All block completion operations are added to the queue in the coroutines. +Queue is flushed at checkpoints and information about processed requests +is recorded to the log. In replay phase the queue is matched with +events read from the log. Therefore block devices requests are processed +deterministically. + +Snapshotting +------------ + +New VM snapshots may be created in replay mode. They can be used later +to recover the desired VM state. All VM states created in replay mode +are associated with the moment of time in the replay scenario. +After recovering the VM state replay will start from that position. + +Default starting snapshot name may be specified with icount field +rrsnapshot as follows: + -icount shift=7,rr=record,rrfile=replay.bin,rrsnapshot=snapshot_name + +This snapshot is created at start of recording and restored at start +of replaying. It also can be loaded while replaying to roll back +the execution. + +'snapshot' flag of the disk image must be removed to save the snapshots +in the overlay (or original image) instead of using the temporary overlay. + -drive file=disk.ovl,if=none,id=img-direct + -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay + -device ide-hd,drive=img-blkreplay + +Use QEMU monitor to create additional snapshots. 'savevm ' command +created the snapshot and 'loadvm ' restores it. To prevent corruption +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 +--------------- + +Record and replay for network interactions is performed with the network filter. +Each backend must have its own instance of the replay filter as follows: + -netdev user,id=net1 -device rtl8139,netdev=net1 + -object filter-replay,id=replay,netdev=net1 + +Replay network filter is used to record and replay network packets. While +recording the virtual machine this filter puts all packets coming from +the outer world into the log. In replay mode packets from the log are +injected into the network device. All interactions with network backend +in replay mode are disabled. + +Audio devices +------------- + +Audio data is recorded and replay automatically. The command line for recording +and replaying must contain identical specifications of audio hardware, e.g.: + -soundhw ac97 + +Serial ports +------------ + +Serial ports input is recorded and replay automatically. The command lines +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 +----------------- + +Record/replay log consists of the header and the sequence of execution +events. The header includes 4-byte replay version id and 8-byte reserved +field. Version is updated every time replay log format changes to prevent +using replay log created by another build of qemu. + +The sequence of the events describes virtual machine state changes. +It includes all non-deterministic inputs of VM, synchronization marks and +instruction counts used to correctly inject inputs at replay. + +Synchronization marks (checkpoints) are used for synchronizing qemu threads +that perform operations with virtual hardware. These operations may change +system's state (e.g., change some register or generate interrupt) and +therefore should execute synchronously with CPU thread. + +Every event in the log includes 1-byte event id and optional arguments. +When argument is an array, it is stored as 4-byte array length +and corresponding number of bytes with data. +Here is the list of events that are written into the log: + + - EVENT_INSTRUCTION. Instructions executed since last event. + Argument: 4-byte number of executed instructions. + - EVENT_INTERRUPT. Used to synchronize interrupt processing. + - EVENT_EXCEPTION. Used to synchronize exception handling. + - EVENT_ASYNC. This is a group of events. They are always processed + together with checkpoints. When such an event is generated, it is + stored in the queue and processed only when checkpoint occurs. + Every such event is followed by 1-byte checkpoint id and 1-byte + async event id from the following list: + - REPLAY_ASYNC_EVENT_BH. Bottom-half callback. This event synchronizes + callbacks that affect virtual machine state, but normally called + asynchronously. + Argument: 8-byte operation id. + - REPLAY_ASYNC_EVENT_INPUT. Input device event. Contains + parameters of keyboard and mouse input operations + (key press/release, mouse pointer movement). + Arguments: 9-16 bytes depending of input event. + - REPLAY_ASYNC_EVENT_INPUT_SYNC. Internal input synchronization event. + - REPLAY_ASYNC_EVENT_CHAR_READ. Character (e.g., serial port) device input + initiated by the sender. + Arguments: 1-byte character device id. + Array with bytes were read. + - REPLAY_ASYNC_EVENT_BLOCK. Block device operation. Used to synchronize + operations with disk and flash drives with CPU. + Argument: 8-byte operation id. + - REPLAY_ASYNC_EVENT_NET. Incoming network packet. + Arguments: 1-byte network adapter id. + 4-byte packet flags. + Array with packet bytes. + - EVENT_SHUTDOWN. Occurs when user sends shutdown event to qemu, + e.g., by closing the window. + - EVENT_CHAR_WRITE. Used to synchronize character output operations. + Arguments: 4-byte output function return value. + 4-byte offset in the output array. + - EVENT_CHAR_READ_ALL. Used to synchronize character input operations, + initiated by qemu. + Argument: Array with bytes that were read. + - EVENT_CHAR_READ_ALL_ERROR. Unsuccessful character input operation, + initiated by qemu. + Argument: 4-byte error code. + - EVENT_CLOCK + clock_id. Group of events for host clock read operations. + Argument: 8-byte clock value. + - EVENT_CHECKPOINT + checkpoint_id. Checkpoint for synchronization of + CPU, internal threads, and asynchronous input events. May be followed + by one or more EVENT_ASYNC events. + - EVENT_END. Last event in the log. From patchwork Mon Sep 14 06:07:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 305516 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 78247C43461 for ; Mon, 14 Sep 2020 06:18:27 +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 EAEDA20756 for ; Mon, 14 Sep 2020 06:18:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAEDA20756 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]:39048 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhoo-0004Wv-3L for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:18:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37214) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhea-0004vG-Kj for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:52 -0400 Received: from mail.ispras.ru ([83.149.199.84]:45040) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHheX-0002SE-Md for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:52 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 989E840A2048; Mon, 14 Sep 2020 06:07:47 +0000 (UTC) Subject: [PATCH v4 14/15] replay: create temporary snapshot at debugger connection From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:47 +0300 Message-ID: <160006366727.31457.2381184404739671543.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" 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 --- gdbstub.c | 1 + include/sysemu/replay.h | 2 ++ replay/replay-debugging.c | 16 ++++++++++++++++ 3 files changed, 19 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 d02d4e0766..bb9110707a 100644 --- a/replay/replay-debugging.c +++ b/replay/replay-debugging.c @@ -316,3 +316,19 @@ 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) { + Error *err = NULL; + if (save_snapshot("start_debugging", &err) != 0) { + /* Can't create the snapshot. Continue conventional debugging. */ + error_free(err); + } + } +} From patchwork Mon Sep 14 06:07:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 273849 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 E1614C43461 for ; Mon, 14 Sep 2020 06:11:33 +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 9938D206F4 for ; Mon, 14 Sep 2020 06:11:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9938D206F4 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]:44696 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHhi8-0003bt-MS for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 02:11:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37248) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHheg-0005AS-1p for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:58 -0400 Received: from mail.ispras.ru ([83.149.199.84]:45044) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHhed-0002TF-BT for qemu-devel@nongnu.org; Mon, 14 Sep 2020 02:07:57 -0400 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 66E0440A2055; Mon, 14 Sep 2020 06:07:53 +0000 (UTC) Subject: [PATCH v4 15/15] tests/acceptance: add reverse debugging test From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Mon, 14 Sep 2020 09:07:53 +0300 Message-ID: <160006367307.31457.8896551368353881221.stgit@pasha-ThinkPad-X280> In-Reply-To: <160006358590.31457.16757371597343007847.stgit@pasha-ThinkPad-X280> References: <160006358590.31457.16757371597343007847.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 = 2020/09/14 02:06:27 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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" From: Pavel Dovgalyuk 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 --- MAINTAINERS | 1 tests/acceptance/reverse_debugging.py | 203 +++++++++++++++++++++++++++++++++ 2 files changed, 204 insertions(+) create mode 100644 tests/acceptance/reverse_debugging.py diff --git a/MAINTAINERS b/MAINTAINERS index 7724fd3f8a..227d15a3ad 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2661,6 +2661,7 @@ 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..dda42e1c1a --- /dev/null +++ b/tests/acceptance/reverse_debugging.py @@ -0,0 +1,203 @@ +# Reverse debugging test +# +# Copyright (c) 2020 ISP RAS +# +# Author: +# Pavel Dovgalyuk +# +# 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_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 + + 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 + + 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'))