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 65A66C433F5 for ; Mon, 3 Oct 2022 10:22:34 +0000 (UTC) Received: from localhost ([::1]:48860 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ofIan-0000DO-6J for qemu-devel@archiver.kernel.org; Mon, 03 Oct 2022 06:22:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50996) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ofISM-0004jI-9e for qemu-devel@nongnu.org; Mon, 03 Oct 2022 06:13:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:27853) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ofISI-0007CC-Uq for qemu-devel@nongnu.org; Mon, 03 Oct 2022 06:13:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664792025; 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=QDFE4hWKiGIoEWEycfYjOqCKF3pB1knVwiEANmltENM=; b=AS2KYSceKTwCxGfx5B2VrhC84o9GGVtIWdAR7bqRRRXbnXWfw9jmIhrHQUpXXgk/oKA1uA zBNQLw6Qt4GQc0zfmhtGH5ip0DxhMPKVy+D79Odz96XvDsZiZ5aBgb9GV9lMOJdoUQoYR8 nyNwRqxZAJCo+yxKFf7ArhJxXVl/GZQ= Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-673-U9UawYUtOC2itibCffPGMg-1; Mon, 03 Oct 2022 06:13:44 -0400 X-MC-Unique: U9UawYUtOC2itibCffPGMg-1 Received: by mail-oo1-f71.google.com with SMTP id n5-20020a4a3445000000b004728fe7a331so6036868oof.23 for ; Mon, 03 Oct 2022 03:13:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date; bh=QDFE4hWKiGIoEWEycfYjOqCKF3pB1knVwiEANmltENM=; b=r10BEM8fLyOVEbnxmRgddhghFgpFugZGqHc072C7aihy8KEMSFZn3To/tCMn8iI7Uw v/mNiGNIxyTmTdaTIZdyOpea2Qokgk9HC1rVeP24w/ePoheJylLibQ411qlkJlc5G3y9 4ap4vza2SJPJ42rDBK/TkViUUpnQvjyVCoO2PNvdaS9zRp3fvE7UWZZxM5xSequISCp5 jjvrQ06HgAaRZ66QxMtg+6n+lvon0uW5WIaHvJ8kkXtkPnAcvq3eWeHh777BLRvkwc3H mK9dA3hAMokzCcF7CFl0AoTSIpCOiwExp87Gzq8pshhbtAxekO3PvI6R6IExBfDA5Hwy kUXw== X-Gm-Message-State: ACrzQf085NYNI24YF3JPlV1fDrXTx9SU6bPnzLZbuU3LC1ltAHNWZ/xv dPyfrEn86s94AtNmOjbR0VUz/odvlbdEfMmubCkEYlzQnLe5I+7AiLnNlq9jogrhwlt9h2hLKc3 QAGXx2C0sBAebWyHALjPEjDW0G8ZLRfw= X-Received: by 2002:a05:6830:b8d:b0:65f:22fb:be09 with SMTP id a13-20020a0568300b8d00b0065f22fbbe09mr3195090otv.38.1664792023926; Mon, 03 Oct 2022 03:13:43 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5Bs1/vfWX4SyahpaIPuRrZJTtmPCWurS4lydAvnO/KaJmhXWXxeghe062OJjyNijRdUutUZQBp+rGhVfcCKkU= X-Received: by 2002:a05:6830:b8d:b0:65f:22fb:be09 with SMTP id a13-20020a0568300b8d00b0065f22fbbe09mr3195081otv.38.1664792023715; Mon, 03 Oct 2022 03:13:43 -0700 (PDT) MIME-Version: 1.0 References: <20221003100612.596845-1-berrange@redhat.com> In-Reply-To: <20221003100612.596845-1-berrange@redhat.com> From: =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= Date: Mon, 3 Oct 2022 14:13:32 +0400 Message-ID: Subject: Re: [PATCH] net: improve error message for missing netdev backend To: =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= Cc: qemu-devel@nongnu.org, Christian Schoenebeck , Thomas Huth , Jason Wang Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=170.10.129.124; envelope-from=mlureau@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, 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: 2.1.29 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" Hi On Mon, Oct 3, 2022 at 2:06 PM Daniel P. Berrang=C3=A9 wrote: > > The current message when using '-net user...' with SLIRP disabled at > compile time is: > > qemu-system-x86_64: -net user: Parameter 'type' expects a net backend t= ype (maybe it is not compiled into this binary) > > An observation is that we're using the 'netdev->type' field here which > is an enum value, produced after QAPI has converted from its string > form. > > IOW, at this point in the code, we know that the user's specified > type name was a valid network backend. The only possible scenario that > can make the backend init function be NULL, is if support for that > backend was disabled at build time. Given this, we don't need to caveat > our error message with a 'maybe' hint, we can be totally explicit. > > The use of QERR_INVALID_PARAMETER_VALUE doesn't really lend itself to > user friendly error message text. Since this is not used to set a > specific QAPI error class, we can simply stop using this pre-formatted > error text and provide something better. > > Thus the new message is: > > qemu-system-x86_64: -net user: network backend 'user' is not compiled i= nto this binary > > The case of passing 'hubport' for -net is also given a message reminding > people they should have used -netdev/-nic instead, as this backend type > is only valid for the modern syntax. > > Signed-off-by: Daniel P. Berrang=C3=A9 lgtm Reviewed-by: Marc-Andr=C3=A9 Lureau > --- > > NB, this does not make any difference to people who were relying on the > QEMU built-in default hub that was created if you don't list any -net / > -netdev / -nic argument, only those using explicit args. > > net/net.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > > diff --git a/net/net.c b/net/net.c > index 2db160e063..8ddafacf13 100644 > --- a/net/net.c > +++ b/net/net.c > @@ -1036,19 +1036,23 @@ static int net_client_init1(const Netdev *netdev,= bool is_netdev, Error **errp) > if (is_netdev) { > if (netdev->type =3D=3D NET_CLIENT_DRIVER_NIC || > !net_client_init_fun[netdev->type]) { > - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type", > - "a netdev backend type"); > + error_setg(errp, "network backend '%s' is not compiled into = this binary", > + NetClientDriver_str(netdev->type)); > return -1; > } > } else { > if (netdev->type =3D=3D NET_CLIENT_DRIVER_NONE) { > return 0; /* nothing to do */ > } > - if (netdev->type =3D=3D NET_CLIENT_DRIVER_HUBPORT || > - !net_client_init_fun[netdev->type]) { > - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type", > - "a net backend type (maybe it is not compiled " > - "into this binary)"); > + if (netdev->type =3D=3D NET_CLIENT_DRIVER_HUBPORT) { > + error_setg(errp, "network backend '%s' is only supported wit= h -netdev/-nic", > + NetClientDriver_str(netdev->type)); > + return -1; > + } > + > + if (!net_client_init_fun[netdev->type]) { > + error_setg(errp, "network backend '%s' is not compiled into = this binary", > + NetClientDriver_str(netdev->type)); > return -1; > } > > -- > 2.37.3 >