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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLACK,URIBL_BLOCKED,USER_AGENT_SANE_2 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 C7EE8C47404 for ; Wed, 9 Oct 2019 17:38:05 +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 9F4B6206BB for ; Wed, 9 Oct 2019 17:38:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F4B6206BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaod.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53160 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIFuW-00042t-B4 for qemu-devel@archiver.kernel.org; Wed, 09 Oct 2019 13:38:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46993) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iI7Tq-0007yO-UF for qemu-devel@nongnu.org; Wed, 09 Oct 2019 04:38:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iI7Tp-0000Md-DD for qemu-devel@nongnu.org; Wed, 09 Oct 2019 04:37:58 -0400 Received: from 6.mo2.mail-out.ovh.net ([87.98.165.38]:39984) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iI7Tp-0000L0-2i for qemu-devel@nongnu.org; Wed, 09 Oct 2019 04:37:57 -0400 Received: from player714.ha.ovh.net (unknown [10.109.159.90]) by mo2.mail-out.ovh.net (Postfix) with ESMTP id 9FFBF1AEE4F for ; Wed, 9 Oct 2019 10:37:54 +0200 (CEST) Received: from kaod.org (lns-bzn-46-82-253-208-248.adsl.proxad.net [82.253.208.248]) (Authenticated sender: groug@kaod.org) by player714.ha.ovh.net (Postfix) with ESMTPSA id 3822BAAEB6B8; Wed, 9 Oct 2019 08:37:40 +0000 (UTC) Date: Wed, 9 Oct 2019 10:37:38 +0200 From: Greg Kurz To: David Gibson Subject: Re: [PATCH v4 19/19] spapr: Work around spurious warnings from vfio INTx initialization Message-ID: <20191009103738.01bc146a@bahia.lan> In-Reply-To: <20191009060818.29719-20-david@gibson.dropbear.id.au> References: <20191009060818.29719-1-david@gibson.dropbear.id.au> <20191009060818.29719-20-david@gibson.dropbear.id.au> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Ovh-Tracer-Id: 11268569217915656678 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedufedriedtgddufeegucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 87.98.165.38 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: Alexey Kardashevskiy , Jason Wang , Riku Voipio , qemu-devel@nongnu.org, Laurent Vivier , Alex Williamson , qemu-ppc@nongnu.org, clg@kaod.org, Paolo Bonzini , =?UTF-8?B?TWFyYy1BbmRyw6k=?= Lureau , philmd@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 9 Oct 2019 17:08:18 +1100 David Gibson wrote: > Traditional PCI INTx for vfio devices can only perform well if using > an in-kernel irqchip. Therefore, vfio_intx_update() issues a warning > if an in kernel irqchip is not available. > Can you elaborate on what doesn't "perform well" without an in-kernel irqchip ? Is it a matter of performance or is it actually broken or something else ? What is the impact on -machine accel=kvm,kernel-irqchip=off which always spit this warning ? > We usually do have an in-kernel irqchip available for pseries machines > on POWER hosts. However, because the platform allows feature > negotiation of what interrupt controller model to use, we don't > currently initialize it until machine reset. vfio_intx_update() is > called (first) from vfio_realize() before that, so it can issue a > spurious warning, even if we will have an in kernel irqchip by the > time we need it. > > To workaround this, make a call to spapr_irq_update_active_intc() from > spapr_irq_init() which is called at machine realize time, before the > vfio realize. This call will be pretty much obsoleted by the later > call at reset time, but it serves to suppress the spurious warning > from VFIO. > > Cc: Alex Williamson > Cc: Alexey Kardashevskiy > > Signed-off-by: David Gibson > --- > hw/ppc/spapr_irq.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c > index 7964e4a1b8..3aeb523f3e 100644 > --- a/hw/ppc/spapr_irq.c > +++ b/hw/ppc/spapr_irq.c > @@ -274,6 +274,14 @@ void spapr_irq_init(SpaprMachineState *spapr, Error **errp) > > spapr->qirqs = qemu_allocate_irqs(spapr_set_irq, spapr, > smc->nr_xirqs + SPAPR_XIRQ_BASE); > + > + /* > + * Mostly we don't actually need this until reset, except that not > + * having this set up can cause VFIO devices to issue a > + * false-positive warning during realize(), because they don't yet > + * have an in-kernel irq chip. > + */ > + spapr_irq_update_active_intc(spapr); > } > > int spapr_irq_claim(SpaprMachineState *spapr, int irq, bool lsi, Error **errp) > @@ -429,7 +437,8 @@ void spapr_irq_update_active_intc(SpaprMachineState *spapr) > * this. > */ > new_intc = SPAPR_INTC(spapr->xive); > - } else if (spapr_ovec_test(spapr->ov5_cas, OV5_XIVE_EXPLOIT)) { > + } else if (spapr->ov5_cas > + && spapr_ovec_test(spapr->ov5_cas, OV5_XIVE_EXPLOIT)) { > new_intc = SPAPR_INTC(spapr->xive); > } else { > new_intc = SPAPR_INTC(spapr->ics);