From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52065) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gPVdI-0008P6-Pn for qemu-devel@nongnu.org; Wed, 21 Nov 2018 11:45:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gPVdF-00083j-Li for qemu-devel@nongnu.org; Wed, 21 Nov 2018 11:45:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40138) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gPVdF-00082Y-DO for qemu-devel@nongnu.org; Wed, 21 Nov 2018 11:45:41 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C7FBF307D86D for ; Wed, 21 Nov 2018 16:45:40 +0000 (UTC) References: <20181120165300.18993-1-wainersm@redhat.com> <20181120190238.GR4755@habkost.net> <20181121155559.GB32503@localhost.localdomain> From: Wainer dos Santos Moschetta Message-ID: Date: Wed, 21 Nov 2018 14:45:20 -0200 MIME-Version: 1.0 In-Reply-To: <20181121155559.GB32503@localhost.localdomain> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [Qemu-devel] [PATCH] scripts/qemu.py: allow to launch the VM without a monitor List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Caio Carrara , Eduardo Habkost Cc: philmd@redhat.com, qemu-devel@nongnu.org, crosa@redhat.com On 11/21/2018 01:56 PM, Caio Carrara wrote: > Hello Wainer and Eduardo, > > On Tue, Nov 20, 2018 at 05:02:38PM -0200, Eduardo Habkost wrote: >> On Tue, Nov 20, 2018 at 11:53:00AM -0500, Wainer dos Santos Moschetta wrote: >>> QEMUMachine launches the VM with a monitor enabled, afterwards >>> a qmp connection is attempted on _post_launch(). In case >>> the QEMU process exits with an error, qmp.accept() reaches >>> timeout and raises an exception. >>> >>> But sometimes you don't need that monitor. As an example, >>> when a test launches the VM expects its immediate crash, >>> and only intend to check the process's return code. In this >>> case the fact that launch() tries to establish the qmp >>> connection (ending up in an exception) is troublesome. >>> >>> So this patch adds the disable_qmp() that allow to >>> launch the VM without creating the monitor machinery. >>> > {...} >>> + >>> + self._args.extend(['-chardev', moncdev, '-mon', 'chardev=mon,mode=control']) >> This will extend self._args multiple times if making a >> .shutdown()/.launch() cycle: >> > {...} >> Why did you move this code outside _base_args(), where it already >> worked without relying on method side-effects and required no >> extra state to be kept inside self._args? > Eduardo, I think the purpose was to get a way to set up the monitor > conditionally. So the arguments related with monitor was moved out > _base_args() method and put into the _setup_qmp(). However, as you > showed, this implementation has undesired side-effects. > > Wainer, probably the most straightforward way to add this capability to > QEMUMachine is to change the _base_args() method to only include monitor > arguments when necessary. Something like this: > > ``` > # create a proper method to get moncdev_args > def _get_moncdev_args(): > if isinstance(self._monitor_address, tuple): > return "socket,id=mon,host=%s,port=%s" % ( > self._monitor_address[0], > self._monitor_address[1]) > else: > return 'socket,id=mon,path=%s' % self._vm_monitor > > # update _base_args method to use new attribute _with_qmp > def _base_args(self): > args = ['-display', 'none', '-vga', 'none'] > if self._with_qmp: > args.extend(['-chardev', self._get_moncdev_args(), > '-mon', 'chardev=mon,mode=control']) > if self._machine is not None: > ``` > > Does it make sense? It does. I will send a v2 on that line. Thanks for the review Caio and Eduardo! - Wainer > > {...} >> -- >> Eduardo