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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 44CEEC433EF for ; Mon, 20 Jun 2022 12:49:08 +0000 (UTC) Received: from localhost ([::1]:40692 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o3Gq3-0003aO-30 for qemu-devel@archiver.kernel.org; Mon, 20 Jun 2022 08:49:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33896) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o3Gko-0000BL-L9 for qemu-devel@nongnu.org; Mon, 20 Jun 2022 08:43:44 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:44063) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o3Gkl-0004QB-5K for qemu-devel@nongnu.org; Mon, 20 Jun 2022 08:43:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655729018; 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: in-reply-to:in-reply-to:references:references; bh=IFLIO3KxMKAFTsO8iti4RzxWuyBARI2RFvvUEWVB3L4=; b=UEJSY5ZJBuFgzv0Xw0C/c2pGNV+oFHURpRodIojp9Q34zrPsuj7+SwEwBQYEFLQxS2ANOD 3PZ+gNQxE8JjJ/wcu/BgFwKU/BvNC1vZaSpi68x9+6Wd+7DmmXuN3Li6ahc6/c/WT/nYt5 OBWP3qgyWu6vXfuaiz3Fp4tik1hmNfE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-77-fCt6YF7qNemmCy3fz96MYA-1; Mon, 20 Jun 2022 08:43:37 -0400 X-MC-Unique: fCt6YF7qNemmCy3fz96MYA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E4BA6101E9BB for ; Mon, 20 Jun 2022 12:43:36 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.195.112]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9FD0640466AD; Mon, 20 Jun 2022 12:43:36 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 612D121E688E; Mon, 20 Jun 2022 14:43:35 +0200 (CEST) From: Markus Armbruster To: Laurent Vivier Cc: qemu-devel@nongnu.org, Eric Blake , "Dr. David Alan Gilbert" , Paolo Bonzini , Daniel P. =?utf-8?Q?Berrang=C3=A9?= , Jason Wang Subject: Re: [RFC PATCH v3 03/11] qapi: net: introduce a way to bypass qemu_opts_parse_noisily() References: <20220620101828.518865-1-lvivier@redhat.com> <20220620101828.518865-4-lvivier@redhat.com> Date: Mon, 20 Jun 2022 14:43:35 +0200 In-Reply-To: <20220620101828.518865-4-lvivier@redhat.com> (Laurent Vivier's message of "Mon, 20 Jun 2022 12:18:20 +0200") Message-ID: <87ilov1p54.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Laurent Vivier writes: > As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field > of Netdev structure can collides with "type" field of SocketAddress), > we introduce a way to bypass qemu_opts_parse_noisily() and use directly > visit_type_Netdev() to parse the backend parameters. > > More details from Markus: > > qemu_init() passes the argument of -netdev, -nic, and -net to > net_client_parse(). > > net_client_parse() parses with qemu_opts_parse_noisily(), passing > QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and > qemu_net_opts for -net. Their desc[] are all empty, which means any > keys are accepted. The result of the parse (a QemuOpts) is stored in > the QemuOptsList. > > Note that QemuOpts is flat by design. In some places, we layer non-flat > on top using dotted keys convention, but not here. > > net_init_clients() iterates over the stored QemuOpts, and passes them to > net_init_netdev(), net_param_nic(), or net_init_client(), respectively. > > These functions pass the QemuOpts to net_client_init(). They also do > other things with the QemuOpts, which we can ignore here. > > net_client_init() uses the opts visitor to convert the (flat) QemOpts to > a (non-flat) QAPI object Netdev. Netdev is also the argument of QMP > command netdev_add. > > The opts visitor was an early attempt to support QAPI in > (QemuOpts-based) CLI. It restricts QAPI types to a certain shape; see > commit eb7ee2cbeb "qapi: introduce OptsVisitor". > > A more modern way to support QAPI is qobject_input_visitor_new_str(). > It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and > it also supports JSON syntax. The former isn't quite as expressive as > JSON, but it's a lot closer than QemuOpts + opts visitor. > > This commit paves the way to use of the modern way instead. > > Signed-off-by: Laurent Vivier > --- > include/net/net.h | 1 + > net/net.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++ > softmmu/vl.c | 3 ++- > 3 files changed, 63 insertions(+), 1 deletion(-) > > diff --git a/include/net/net.h b/include/net/net.h > index c53c64ac18c4..4ae8ed480f73 100644 > --- a/include/net/net.h > +++ b/include/net/net.h > @@ -214,6 +214,7 @@ extern NICInfo nd_table[MAX_NICS]; > extern const char *host_net_devices[]; > > /* from net.c */ > +int netdev_parse_modern(const char *optarg); > int net_client_parse(QemuOptsList *opts_list, const char *str); > void show_netdevs(void); > void net_init_clients(void); > diff --git a/net/net.c b/net/net.c > index 15958f881776..c337d3d753fe 100644 > --- a/net/net.c > +++ b/net/net.c > @@ -54,6 +54,7 @@ > #include "net/colo-compare.h" > #include "net/filter.h" > #include "qapi/string-output-visitor.h" > +#include "qapi/qobject-input-visitor.h" > > /* Net bridge is currently not supported for W32. */ > #if !defined(_WIN32) > @@ -63,6 +64,16 @@ > static VMChangeStateEntry *net_change_state_entry; > static QTAILQ_HEAD(, NetClientState) net_clients; > > +typedef struct NetdevQueueEntry { > + Netdev *nd; > + Location loc; > + QSIMPLEQ_ENTRY(NetdevQueueEntry) entry; > +} NetdevQueueEntry; > + > +typedef QSIMPLEQ_HEAD(, NetdevQueueEntry) NetdevQueue; > + > +static NetdevQueue nd_queue = QSIMPLEQ_HEAD_INITIALIZER(nd_queue); > + > /***********************************************************/ > /* network device redirectors */ > > @@ -1562,6 +1573,20 @@ out: > return ret; > } > > +static void netdev_init_modern(void) > +{ > + while (!QSIMPLEQ_EMPTY(&nd_queue)) { > + NetdevQueueEntry *nd = QSIMPLEQ_FIRST(&nd_queue); > + > + QSIMPLEQ_REMOVE_HEAD(&nd_queue, entry); > + loc_push_restore(&nd->loc); > + net_client_init1(nd->nd, true, &error_fatal); > + loc_pop(&nd->loc); > + qapi_free_Netdev(nd->nd); > + g_free(nd); > + } > +} > + > void net_init_clients(void) > { > net_change_state_entry = > @@ -1569,6 +1594,8 @@ void net_init_clients(void) > > QTAILQ_INIT(&net_clients); > > + netdev_init_modern(); > + > qemu_opts_foreach(qemu_find_opts("netdev"), net_init_netdev, NULL, > &error_fatal); > > @@ -1579,6 +1606,39 @@ void net_init_clients(void) > &error_fatal); > } > > +/* > + * netdev_is_modern() returns true when the backend needs to bypass > + * qemu_opts_parse_noisily() > + */ > +static bool netdev_is_modern(const char *optarg) > +{ > + return false; > +} > + > +/* > + * netdev_parse_modern() uses modern, more expressive syntax than > + * net_client_parse(), supports only the netdev option. > + */ > +int netdev_parse_modern(const char *optarg) > +{ > + Visitor *v; > + NetdevQueueEntry *nd; > + > + if (!netdev_is_modern(optarg)) { > + return -1; > + } > + > + v = qobject_input_visitor_new_str(optarg, "type", &error_fatal); > + nd = g_new(NetdevQueueEntry, 1); > + visit_type_Netdev(v, NULL, &nd->nd, &error_fatal); > + visit_free(v); > + loc_save(&nd->loc); > + > + QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry); > + > + return 0; > +} > + > int net_client_parse(QemuOptsList *opts_list, const char *optarg) > { > if (!qemu_opts_parse_noisily(opts_list, optarg, true)) { > diff --git a/softmmu/vl.c b/softmmu/vl.c > index 8eed0f31c073..838f5b48c447 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -2839,7 +2839,8 @@ void qemu_init(int argc, char **argv, char **envp) > break; > case QEMU_OPTION_netdev: > default_net = 0; > - if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { > + if (netdev_parse_modern(optarg) == -1 && > + net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { > exit(1); > } > break; To make this work, netdev_parse_modern() must * either succeeed, or * fail without reporting an error, or * report an error and exit() Recommend to spell that out in its function comment. Alternatively: if (netdev_is_modern(optarg)) { netdev_parse_modern(optarg); } else { if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { exit(1); } } netdev_is_modern() needs external linkage, and netdev_parse_modern() loses its return value. Note that all callers net_client_parse() handle failure exactly the same way. If we let net_client_parse() exit(), then this becomes if (netdev_is_modern(optarg)) { netdev_parse_modern(optarg); } else { net_client_parse(qemu_find_opts("netdev"), optarg); } I like this one best. What do you think? Regardless of which alternative we pick: error reporting depends on netdev_is_modern(). To be discussed in my review of the next patch.