From patchwork Thu Mar 11 07:14:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 12130533 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 54704C433E0 for ; Thu, 11 Mar 2021 07:16:17 +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 7161464E77 for ; Thu, 11 Mar 2021 07:16:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7161464E77 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]:39056 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lKFYN-00028n-4M for qemu-devel@archiver.kernel.org; Thu, 11 Mar 2021 02:16:15 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53088) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lKFWU-0001QJ-CV for qemu-devel@nongnu.org; Thu, 11 Mar 2021 02:14:18 -0500 Received: from mail.ispras.ru ([83.149.199.84]:35004) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lKFWS-0001g1-2x for qemu-devel@nongnu.org; Thu, 11 Mar 2021 02:14:18 -0500 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 6356940755EC; Thu, 11 Mar 2021 07:14:08 +0000 (UTC) Subject: [PATCH] replay: don't wait in run_on_cpu From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Thu, 11 Mar 2021 10:14:08 +0300 Message-ID: <161544684811.80476.11634004581744007934.stgit@pasha-ThinkPad-X280> User-Agent: StGit/0.23 MIME-Version: 1.0 Received-SPF: pass client-ip=83.149.199.84; envelope-from=pavel.dovgalyuk@ispras.ru; helo=mail.ispras.ru 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: pbonzini@redhat.com, richard.henderson@linaro.org, pavel.dovgalyuk@ispras.ru Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" In record/replay mode waiting for vCPU to execute the task scheduled by run_on_cpu may lead to deadlock, because when run_on_cpu is executed in main_loop (e.g., in loadvm processing) it holds replay mutex. This patch allows running scheduled task in iothread when it holds the replay mutex. Signed-off-by: Pavel Dovgalyuk --- cpus-common.c | 9 ++++++++- include/sysemu/replay.h | 1 + replay/replay-internal.h | 1 - stubs/replay-tools.c | 5 +++++ 4 files changed, 14 insertions(+), 2 deletions(-) diff --git a/cpus-common.c b/cpus-common.c index 6e73d3e58d..38ff510175 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -23,6 +23,7 @@ #include "hw/core/cpu.h" #include "sysemu/cpus.h" #include "qemu/lockable.h" +#include "sysemu/replay.h" static QemuMutex qemu_cpu_list_lock; static QemuCond exclusive_cond; @@ -136,7 +137,13 @@ void do_run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data, { struct qemu_work_item wi; - if (qemu_cpu_is_self(cpu)) { + if (qemu_cpu_is_self(cpu) + /* + * vCPU thread is waiting when replay mutex is locked + * and the task is not exclusive, the function may be called + * without other synchronization. + */ + || (replay_mode != REPLAY_MODE_NONE && replay_mutex_locked())) { func(cpu, data); return; } diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h index 0f3b0f7eac..032256533b 100644 --- a/include/sysemu/replay.h +++ b/include/sysemu/replay.h @@ -62,6 +62,7 @@ extern char *replay_snapshot; void replay_mutex_lock(void); void replay_mutex_unlock(void); +bool replay_mutex_locked(void); /* Replay process control functions */ diff --git a/replay/replay-internal.h b/replay/replay-internal.h index 97649ed8d7..dada623527 100644 --- a/replay/replay-internal.h +++ b/replay/replay-internal.h @@ -117,7 +117,6 @@ void replay_get_array_alloc(uint8_t **buf, size_t *size); * synchronisation between vCPU and main-loop threads. */ void replay_mutex_init(void); -bool replay_mutex_locked(void); /*! Checks error status of the file. */ void replay_check_error(void); diff --git a/stubs/replay-tools.c b/stubs/replay-tools.c index 43296b3d4e..a42f2483d5 100644 --- a/stubs/replay-tools.c +++ b/stubs/replay-tools.c @@ -48,6 +48,11 @@ void replay_mutex_unlock(void) { } +bool replay_mutex_locked(void) +{ + return false; +} + void replay_register_char_driver(Chardev *chr) { }