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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 7E5E9C433DF for ; Mon, 25 May 2020 06:26:33 +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 4477B2078B for ; Mon, 25 May 2020 06:26:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Xt41kFMJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4477B2078B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43902 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jd6ZE-0005Wa-Bq for qemu-devel@archiver.kernel.org; Mon, 25 May 2020 02:26:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58340) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jd6YJ-00050r-BL for qemu-devel@nongnu.org; Mon, 25 May 2020 02:25:35 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:43537 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jd6YH-0008JN-Hi for qemu-devel@nongnu.org; Mon, 25 May 2020 02:25:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590387931; 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=4t5L2kiuQXodLstMq8/yHzwVtOdcs/IM8mwHrpAUS74=; b=Xt41kFMJIf+GE663YHBA1bYWiU1vwjsOB1OOY6RLvr+GPLNfbqJwPzNcb4x9jSFZukXe/5 kTlkT8ifUde7OAAqyh/6kbtE4vbIp5DUUoXhq1GWouYGMcIvb7lCkSUZ1wc1K8aWLoW85D MdTgfcrvG43kA+R0nBSIqbcfZkEM7MU= 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-349-IpiNKflCMwCdqjCwsSP8Dg-1; Mon, 25 May 2020 02:25:25 -0400 X-MC-Unique: IpiNKflCMwCdqjCwsSP8Dg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BC899872FE2; Mon, 25 May 2020 06:25:24 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-32.ams2.redhat.com [10.36.112.32]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 666E38384C; Mon, 25 May 2020 06:25:24 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id E9A5A113864A; Mon, 25 May 2020 08:25:22 +0200 (CEST) From: Markus Armbruster To: Peter Maydell Subject: Re: [PATCH 09/24] macio: Fix to realize "mos6522-cuda" and "mos6522-pmu" devices References: <20200518050408.4579-1-armbru@redhat.com> <20200518050408.4579-10-armbru@redhat.com> Date: Mon, 25 May 2020 08:25:22 +0200 In-Reply-To: (Peter Maydell's message of "Thu, 21 May 2020 17:26:50 +0100") Message-ID: <87367oh6p9.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=207.211.31.81; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/25 00:06:24 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: Paolo Bonzini , "Daniel P. Berrange" , Laurent Vivier , Eduardo Habkost , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Peter Maydell writes: > On Mon, 18 May 2020 at 06:12, Markus Armbruster wrote: >> >> cuda_init() creates a "mos6522-cuda" device, but it's never realized. >> Affects machines mac99 with via=cuda (default) and g3beige. >> >> pmu_init() creates a "mos6522-pmu" device, but it's never realized. >> Affects machine mac99 with via=pmu and via=pmu-adb, >> >> I wonder how this ever worked. If the "device becomes real only on >> realize" thing actually works, then we've always been missing these >> devices, yet nobody noticed. > > Same remark as elsewhere: the devices aren't missing, we just > got lucky that using them in a half-initialized state happens > to work for these devices. Could you update the commit messages > when you reroll this series, please? Of course. What about something like this: In theory, a device becomes real only on realize. In practice, the transition from unreal to real is a fuzzy one. The work to make a device real can be spread between realize methods (fine), instance_init methods (wrong), and board code wiring up the device (fine as long as it effectively happens on realize). Depending on what exactly is done where, a device can work even when we neglect to realize it. Nevertheless, it's a clear misuse of the interface. Even when it works today (more or less by chance), it can break tomorrow. >> Fix by realizing them in cuda_realize() and pmu_realize(), >> respectively. >> >> Fixes: 6dca62a0000f95e0b7020aa00d0ca9b2c421f341 >> Cc: Laurent Vivier >> Signed-off-by: Markus Armbruster >> --- >> hw/misc/macio/cuda.c | 8 +++----- >> hw/misc/macio/pmu.c | 8 +++----- >> 2 files changed, 6 insertions(+), 10 deletions(-) >> >> diff --git a/hw/misc/macio/cuda.c b/hw/misc/macio/cuda.c >> index e0cc0aac5d..6d4d135f71 100644 >> --- a/hw/misc/macio/cuda.c >> +++ b/hw/misc/macio/cuda.c >> @@ -523,15 +523,13 @@ static void cuda_realize(DeviceState *dev, Error **errp) >> { >> CUDAState *s = CUDA(dev); >> SysBusDevice *sbd; >> - MOS6522State *ms; >> - DeviceState *d; >> struct tm tm; >> >> + qdev_init_nofail(DEVICE(&s->mos6522_cuda)); > > Since we init the device with sysbus_init_child_obj() and > we're in a position here to propagate any realize error > back up to our caller, it would be nicer to do this via > setting the realize property rather than qdev_init_nofail(). The error handling will be unreachable. The proper way to say "error not possible" is of course &error_abort, not qdev_init_nofail()'s &error_fatal. Many realize methods misuse the Error interface this way. NULL instead of &error_abort is also common. Cleaning this up is yet another big task. But that's no excuse for making it bigger now. Laurent, would you prefer unreachable error handling or &error_abort? > That's what this patch from March does: > https://lists.gnu.org/archive/html/qemu-devel/2020-03/msg04260.html > (we seem to have let that series drop accidentally, > probably because it was halfway through release and > because it touches several architectures at once). Pity.