From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51836) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQDQw-0008KL-Be for qemu-devel@nongnu.org; Tue, 05 Jun 2018 10:59:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQDQt-0007PU-9e for qemu-devel@nongnu.org; Tue, 05 Jun 2018 10:59:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53622) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fQDQt-0007Of-1a for qemu-devel@nongnu.org; Tue, 05 Jun 2018 10:59:35 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0EFA03002896 for ; Tue, 5 Jun 2018 14:59:34 +0000 (UTC) Date: Tue, 5 Jun 2018 11:59:32 -0300 From: Eduardo Habkost Message-ID: <20180605145932.GJ7451@localhost.localdomain> References: <20180604120345.12955-1-berrange@redhat.com> <20180604120345.12955-2-berrange@redhat.com> <2604e5d5-0e56-62e7-91eb-fd207a907ac8@redhat.com> <20180605005647.GE3184@localhost.localdomain> <20180605103755.34840d5d@redhat.com> <20180605120109.GD7451@localhost.localdomain> <20180605162517.1568aabb@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180605162517.1568aabb@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 1/2] vl: don't use RUN_STATE_PRECONFIG as initial state List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: Michal Privoznik , qemu-devel@nongnu.org, Markus Armbruster , Paolo Bonzini , Max Reitz On Tue, Jun 05, 2018 at 04:25:17PM +0200, Igor Mammedov wrote: > On Tue, 5 Jun 2018 09:01:09 -0300 > Eduardo Habkost wrote: > > > On Tue, Jun 05, 2018 at 10:37:55AM +0200, Igor Mammedov wrote: > > > On Mon, 4 Jun 2018 21:56:47 -0300 > > > Eduardo Habkost wrote: > > > > On Mon, Jun 04, 2018 at 04:21:47PM +0200, Michal Privoznik wrote: > > > > [...] > > > > > > @@ -3572,7 +3570,12 @@ int main(int argc, char **argv, char **envp) > > > > > > } > > > > > > break; > > > > > > case QEMU_OPTION_preconfig: > > > > > > - preconfig_exit_requested = false; > > > > > > + if (!runstate_check(RUN_STATE_NONE)) { > > > > > > + error_report("'--preconfig' and '--incoming' options are " > > > > > > + "mutually exclusive"); > > > > > > + exit(EXIT_FAILURE); > > > > > > + } > > > > > > + runstate_set(RUN_STATE_PRECONFIG); > > > > > > > > > > Specifying --preconfig twice on the command line now fails with a very > > > > > cryptic message (there's no --incoming). > > > > > > > > > > > break; > > > > > > case QEMU_OPTION_enable_kvm: > > > > > > olist = qemu_find_opts("machine"); > > > > > > @@ -3768,9 +3771,12 @@ int main(int argc, char **argv, char **envp) > > > > > > } > > > > > > break; > > > > > > case QEMU_OPTION_incoming: > > > > > > - if (!incoming) { > > > > > > - runstate_set(RUN_STATE_INMIGRATE); > > > > > > + if (!runstate_check(RUN_STATE_NONE)) { > > > > > > + error_report("'--preconfig' and '--incoming' options are " > > > > > > + "mutually exclusive"); > > > > > > + exit(EXIT_FAILURE); > > > > > > } > > > > > > + runstate_set(RUN_STATE_INMIGRATE); > > > > > > > > > > Same here. Specifying --incoming twice fails with cryptic message. But > > > > > one can argue that specifying --incoming twice is wrong anyway. > > > > > > > > > > > > > Initially I was going to suggest simply not changing runstate > > > > during option parsing to avoid this kind of problem, but maybe > > > > this would be a nice way to implement the command-line parsing > > > > rules: > > > Is there a big reason to try making early incoming transition hack nicer? > > > I'd rather leave it as it is for now and fix it properly later > > > (i.e. postponing the transition after machine_done point, which is on my > > > todo list). > > > > Yeah, I'm not sure we want go towards encoding more knowledge in > > the state machine, or keeping the system simple and encoding the > > rules in more straightforward code+variables inside main(). > I've tried before to use code+variables for preconfig checks without > introducing a new runstate and it turned out difficult to manage > and the later changes often broke it. With new runstate end result > was much cleaner. Right. I wasn't talking specifically about the new runstates like PRECONFIG and NONE (which both make sense, IMO), but about my suggestion below to also use runstate transition rules to encode command-line validation and error messages. > > > > > > > > > > > case QEMU_OPTION_preconfig: > > > > /* > > > > * A INCOMING -> PRECONFIG transition would call: > > > > * error_setg("--preconfig and --incoming options are mutually exclusive"); > > > > */ > > > > try_runstate_set(RUN_STATE_PRECONFIG, &error_fatal); > > > > break; > > > > case QEMU_OPTION_incoming: > > > > /* > > > > * A PRECONFIG -> INCOMING transition would also call: > > > > * error_setg("--preconfig and --incoming options are mutually exclusive"); > > > > * > > > > * Maybe a INCOMING -> INCOMING transition could > > > > * result in: > > > > * error_setg("--incoming can't be specified twice"); > > > > */ > > > > try_runstate_set(RUN_STATE_INMIGRATE, &error_fatal); > > > > break; > > > > > > > > > > > > > > incoming = optarg; > > > > > > break; > > > > > > case QEMU_OPTION_only_migratable: > > > > > > > > > > Michal > > > > > > > > > > > > > > > -- Eduardo