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=-7.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 22C19C4338F for ; Fri, 23 Jul 2021 09:47:04 +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 8D8E360E8E for ; Fri, 23 Jul 2021 09:47:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8D8E360E8E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:48650 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m6rlm-0002PA-J2 for qemu-devel@archiver.kernel.org; Fri, 23 Jul 2021 05:47:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51844) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m6rl6-0001jM-Uw for qemu-devel@nongnu.org; Fri, 23 Jul 2021 05:46:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:56142) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m6rl4-0007PT-IY for qemu-devel@nongnu.org; Fri, 23 Jul 2021 05:46:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627033577; 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=9HgamgFluq47Bc5OqZJKTeT+KbYTavRqzCOIvXlzbqc=; b=NaiTzmGwtTPllsEWzBtRC+xZNfB345D2ZGknRwXrXDZp/C7q5eZ5Ofm8wtg1K+fXWrO50Z mj2XDJQVY7fkrsd36bjCemz4Oc4/DIi+e5Fvo8ngpmatposEHyEXuJ1wrTRT422i7C1dzE Kygl4Y564MchufGvtESo28ayp3m2LQw= 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-20-oKnLiQGBOTmLGa_zv2Kx0g-1; Fri, 23 Jul 2021 05:46:16 -0400 X-MC-Unique: oKnLiQGBOTmLGa_zv2Kx0g-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 43529CC624 for ; Fri, 23 Jul 2021 09:46:15 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-114-106.ams2.redhat.com [10.36.114.106]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 07BC93AC1; Fri, 23 Jul 2021 09:46:15 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 6BF7018000A3; Fri, 23 Jul 2021 11:46:13 +0200 (CEST) Date: Fri, 23 Jul 2021 11:46:13 +0200 From: Gerd Hoffmann To: Markus Armbruster Subject: Re: [PATCH 1/2] qxl: remove assert in qxl_pre_save. Message-ID: <20210723094613.zyhljyfhnb5kl2xv@sirius.home.kraxel.org> References: <20210721093347.338536-1-kraxel@redhat.com> <20210721093347.338536-2-kraxel@redhat.com> <20210723063233.ktjex5knfgz77pbq@sirius.home.kraxel.org> <13c8a40f-a879-a981-12f0-36a5289b39b1@redhat.com> <20210723065527.glqc44gyga2lnqyc@sirius.home.kraxel.org> <0196b381-47ca-fb37-d809-e2a25f3c677e@redhat.com> <87im11beuw.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87im11beuw.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kraxel@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.472, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, > >> Migration fails and you want know why. > >> > >> Reason migration fails is the guest violates qxl specs (which doesn't > >> cause actual problems unless you want migrate the guest). > > > > Then I agree error_report() is better ("Report an error to the current > > monitor if we have one, else stderr"). > > No good for QMP, I'm afraid. > > error_report() reports to stderr in QMP monitor context. To get an > error to the QMP client, you need to use error_setg() and propagate all > the way to the QMP core. > > Back to the patch. If the thing we report is actually an *error*, > i.e. something that makes migration fail, then the QMP failure will > contain an error message. That error must come from further up the call > stack. If it's good enough, we don't need error_report() here. Else, > we should error_setg() here. Caller is here (migration/vmstate.c): int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, void *opaque, JSONWriter *vmdesc, int version_id) { [ ... ] if (vmsd->pre_save) { ret = vmsd->pre_save(opaque); trace_vmstate_save_state_pre_save_res(vmsd->name, ret); if (ret) { error_report("pre-save failed: %s", vmsd->name); return ret; } } [ ... ] } No error_setg() anywhere close, it's error_report() all over the place. I guess that makes adding error_report() the only short-term (aka 6.1) option. take care, Gerd