From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 20F81C433E2 for ; Fri, 11 Sep 2020 18:00:56 +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 335E220770 for ; Fri, 11 Sep 2020 18:00:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ga6ZZFc1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 335E220770 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58910 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kGnLx-00080j-Ug for qemu-devel@archiver.kernel.org; Fri, 11 Sep 2020 14:00:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51910) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kGnL4-0007Td-VC for qemu-devel@nongnu.org; Fri, 11 Sep 2020 13:59:58 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:27478 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kGnL3-0004lh-Ak for qemu-devel@nongnu.org; Fri, 11 Sep 2020 13:59:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599847196; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Iek6tYQQw5s6JKqqRLifBEyJCPDsPA0JJc0ey7d3Q90=; b=ga6ZZFc1RfmnfuOoUxBFJvoTj/0Djxl0hTPNXJgrttYahtukJEz9ftZa3WbjsZfBTQH/Ij fRubqcIlauIUlEivKh+IOS3mLWZNpRMBMCxKyO8h7U9cMHLT3qOUVEfDiM4EB/337qhNoj asJ3XxR8O/XlT1NEXuRNDWJIB5epfhc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-274-k7IWXnoJPTG4YCfvqp8jMw-1; Fri, 11 Sep 2020 13:59:52 -0400 X-MC-Unique: k7IWXnoJPTG4YCfvqp8jMw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0E3A1393B6; Fri, 11 Sep 2020 17:59:51 +0000 (UTC) Received: from work-vm (ovpn-113-52.ams2.redhat.com [10.36.113.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4720F60C11; Fri, 11 Sep 2020 17:59:37 +0000 (UTC) Date: Fri, 11 Sep 2020 18:59:34 +0100 From: "Dr. David Alan Gilbert" To: Steven Sistare Subject: Re: [PATCH V1 12/32] vl: pause option Message-ID: <20200911175934.GR3310@work-vm> References: <1596122076-341293-1-git-send-email-steven.sistare@oracle.com> <1596122076-341293-13-git-send-email-steven.sistare@oracle.com> <87r1stdjes.fsf@linaro.org> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/11 03:28:41 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, 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: "Daniel P. Berrange" , "Michael S. Tsirkin" , Alex =?iso-8859-1?Q?Benn=E9e?= , Juan Quintela , qemu-devel@nongnu.org, Markus Armbruster , Alex Williamson , Stefan Hajnoczi , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Paolo Bonzini , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Steven Sistare (steven.sistare@oracle.com) wrote: > On 7/30/2020 1:03 PM, Alex Bennée wrote: > > > > Steve Sistare writes: > > > >> Provide the -pause command-line parameter and the QEMU_PAUSE environment > >> variable to briefly pause QEMU in main and allow a developer to attach gdb. > >> Useful when the developer does not invoke QEMU directly, such as when using > >> libvirt. > > > > How does this differ from -S? > > The -S flag runs qemu to the main loop but does not start the guest. Lots of code > that you may need to debug runs before you get there. You might try the '--preconfig' option - that's pretty early on. The other one is adding a chardev and telling it to wait for a server; that'll wait until you telnet to the port. (Either way, this patch shouldn't really be part of this series, it's a separate discussion) Dave > - Steve > >> Usage: > >> qemu -pause > >> or > >> export QEMU_PAUSE= > >> > >> Signed-off-by: Steve Sistare > >> --- > >> qemu-options.hx | 9 +++++++++ > >> softmmu/vl.c | 15 ++++++++++++++- > >> 2 files changed, 23 insertions(+), 1 deletion(-) > >> > >> diff --git a/qemu-options.hx b/qemu-options.hx > >> index 708583b..8505cf2 100644 > >> --- a/qemu-options.hx > >> +++ b/qemu-options.hx > >> @@ -3668,6 +3668,15 @@ SRST > >> option is experimental. > >> ERST > >> > >> +DEF("pause", HAS_ARG, QEMU_OPTION_pause, \ > >> + "-pause secs Pause for secs seconds on entry to main.\n", QEMU_ARCH_ALL) > >> + > >> +SRST > >> +``--pause secs`` > >> + Pause for a number of seconds on entry to main. Useful for attaching > >> + a debugger after QEMU has been launched by some other entity. > >> +ERST > >> + > > > > It seems like having an option to race with the debugger is just asking > > for trouble. > > > >> DEF("S", 0, QEMU_OPTION_S, \ > >> "-S freeze CPU at startup (use 'c' to start execution)\n", > >> QEMU_ARCH_ALL) > >> diff --git a/softmmu/vl.c b/softmmu/vl.c > >> index 8478778..951994f 100644 > >> --- a/softmmu/vl.c > >> +++ b/softmmu/vl.c > >> @@ -2844,7 +2844,7 @@ static void create_default_memdev(MachineState *ms, const char *path) > >> > >> void qemu_init(int argc, char **argv, char **envp) > >> { > >> - int i; > >> + int i, seconds; > >> int snapshot, linux_boot; > >> const char *initrd_filename; > >> const char *kernel_filename, *kernel_cmdline; > >> @@ -2882,6 +2882,13 @@ void qemu_init(int argc, char **argv, char **envp) > >> QemuPluginList plugin_list = QTAILQ_HEAD_INITIALIZER(plugin_list); > >> int mem_prealloc = 0; /* force preallocation of physical target memory */ > >> > >> + if (getenv("QEMU_PAUSE")) { > >> + seconds = atoi(getenv("QEMU_PAUSE")); > >> + printf("Pausing %d seconds for debugger. QEMU PID is %d\n", > >> + seconds, getpid()); > >> + sleep(seconds); > >> + } > >> + > >> os_set_line_buffering(); > >> > >> error_init(argv[0]); > >> @@ -3204,6 +3211,12 @@ void qemu_init(int argc, char **argv, char **envp) > >> case QEMU_OPTION_gdb: > >> add_device_config(DEV_GDB, optarg); > >> break; > >> + case QEMU_OPTION_pause: > >> + seconds = atoi(optarg); > >> + printf("Pausing %d seconds for debugger. QEMU PID is %d\n", > >> + seconds, getpid()); > >> + sleep(seconds); > >> + break; > >> case QEMU_OPTION_L: > >> if (is_help_option(optarg)) { > >> list_data_dirs = true; > > > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK