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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable 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 3C08CC433E0 for ; Thu, 16 Jul 2020 10:35:29 +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 112872074B for ; Thu, 16 Jul 2020 10:35:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 112872074B 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]:50852 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jw1Ee-0003dF-CJ for qemu-devel@archiver.kernel.org; Thu, 16 Jul 2020 06:35:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60468) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jw1Dv-0002os-Qs for qemu-devel@nongnu.org; Thu, 16 Jul 2020 06:34:43 -0400 Received: from 3.mo179.mail-out.ovh.net ([178.33.251.175]:57865) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jw1Dt-0001lK-8S for qemu-devel@nongnu.org; Thu, 16 Jul 2020 06:34:43 -0400 Received: from player756.ha.ovh.net (unknown [10.110.208.220]) by mo179.mail-out.ovh.net (Postfix) with ESMTP id D7B8B172E9C for ; Thu, 16 Jul 2020 12:34:38 +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 player756.ha.ovh.net (Postfix) with ESMTPSA id 09999138F9FD0; Thu, 16 Jul 2020 10:34:33 +0000 (UTC) Authentication-Results: garm.ovh; auth=pass (GARM-106R006c0787347-977c-43f8-bb79-59c6d966bdb4,82226C5D462F885DC4F8BFF1B5769E1A03475668) smtp.auth=groug@kaod.org Date: Thu, 16 Jul 2020 12:34:30 +0200 From: Greg Kurz To: "Michael S. Tsirkin" Subject: Re: [PATCH] spapr_pci: Robustify support of PCI bridges Message-ID: <20200716123430.12918da6@bahia.lan> In-Reply-To: <20200716025009-mutt-send-email-mst@kernel.org> References: <159431476748.407044.16711294833569014964.stgit@bahia.lan> <20200716025009-mutt-send-email-mst@kernel.org> X-Mailer: Claws Mail 3.17.5 (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: 3260043182197152217 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduiedrfeeggddvlecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpeffhffvuffkjghfofggtgfgsehtjeertdertddvnecuhfhrohhmpefirhgvghcumfhurhiiuceoghhrohhugheskhgrohgurdhorhhgqeenucggtffrrghtthgvrhhnpeehkefhtdehgeehheejledufeekhfdvleefvdeihefhkefhudffhfeuuedvffdthfenucfkpheptddrtddrtddrtddpkedvrddvheefrddvtdekrddvgeeknecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmohguvgepshhmthhpqdhouhhtpdhhvghlohepphhlrgihvghrjeehiedrhhgrrdhovhhhrdhnvghtpdhinhgvtheptddrtddrtddrtddpmhgrihhlfhhrohhmpehgrhhouhhgsehkrghougdrohhrghdprhgtphhtthhopehqvghmuhdquggvvhgvlhesnhhonhhgnhhurdhorhhg Received-SPF: pass client-ip=178.33.251.175; envelope-from=groug@kaod.org; helo=3.mo179.mail-out.ovh.net X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/16 06:34:39 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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: Markus Armbruster , Thomas Huth , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 16 Jul 2020 02:53:07 -0400 "Michael S. Tsirkin" wrote: > On Thu, Jul 09, 2020 at 07:12:47PM +0200, Greg Kurz wrote: > > Some recent error handling cleanups unveiled issues with our support of > > PCI bridges: > > > > 1) QEMU aborts when using non-standard PCI bridge types, > > unveiled by commit 7ef1553dac "spapr_pci: Drop some dead error handling" > > > > $ qemu-system-ppc64 -M pseries -device pcie-pci-bridge > > Unexpected error in object_property_find() at qom/object.c:1240: > > qemu-system-ppc64: -device pcie-pci-bridge: Property '.chassis_nr' not found > > Aborted (core dumped) > > > > This happens because we assume all PCI bridge types to have a "chassis_nr" > > property. This property only exists with the standard PCI bridge type > > "pci-bridge" actually. We could possibly revert 7ef1553dac but it seems > > much simpler to check the presence of "chassis_nr" earlier. > > > > 2) QEMU abort if same "chassis_nr" value is used several times, > > unveiled by commit d2623129a7de "qom: Drop parameter @errp of > > object_property_add() & friends" > > > > $ qemu-system-ppc64 -M pseries -device pci-bridge,chassis_nr=1 \ > > -device pci-bridge,chassis_nr=1 > > Unexpected error in object_property_try_add() at qom/object.c:1167: > > qemu-system-ppc64: -device pci-bridge,chassis_nr=1: attempt to add duplicate property '40000100' to object (type 'container') > > Aborted (core dumped) > > > > This happens because we assume that "chassis_nr" values are unique, but > > nobody enforces that and we end up generating duplicate DRC ids. The PCI > > code doesn't really care for duplicate "chassis_nr" properties since it > > is only used to initialize the "Chassis Number Register" of the bridge, > > with no functional impact on QEMU. So, even if passing the same value > > several times might look weird, it never broke anything before, so > > I guess we don't necessarily want to enforce strict checking in the PCI > > code now. > > > > Workaround both issues in the PAPR code: check that the bridge has a > > unique and non null "chassis_nr" when plugging it into its parent bus. > > > > Fixes: 05929a6c5dfe ("spapr: Don't use bus number for building DRC ids") > > Reported-by: Thomas Huth > > Signed-off-by: Greg Kurz > > > > > --- > > hw/ppc/spapr_pci.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 57 insertions(+) > > > > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c > > index 329002ac040e..09d52ef7954d 100644 > > --- a/hw/ppc/spapr_pci.c > > +++ b/hw/ppc/spapr_pci.c > > @@ -1480,6 +1480,57 @@ static void spapr_pci_bridge_plug(SpaprPhbState *phb, > > add_drcs(phb, bus); > > } > > > > +/* Returns non-zero if the value of "chassis_nr" is already in use */ > > +static int check_chassis_nr(Object *obj, void *opaque) > > +{ > > + int new_chassis_nr = > > + object_property_get_uint(opaque, "chassis_nr", &error_abort); > > + int chassis_nr = > > + object_property_get_uint(obj, "chassis_nr", NULL); > > + > > + if (!object_dynamic_cast(obj, TYPE_PCI_BRIDGE)) { > > + return 0; > > + } > > + > > + /* Skip unsupported bridge types */ > > + if (!chassis_nr) { > > + return 0; > > + } > > + > > + /* Skip self */ > > + if (obj == opaque) { > > + return 0; > > + } > > + > > + return chassis_nr == new_chassis_nr; > > +} > > + > > +static bool bridge_has_valid_chassis_nr(Object *bridge, Error **errp) > > I would rename this "bridge_has_unique_chassis_nr". > Right. > > +{ > > + int chassis_nr = > > + object_property_get_uint(bridge, "chassis_nr", NULL); > > + > > + /* > > + * slotid_cap_init() already ensures that "chassis_nr" isn't null for > > + * standard PCI bridges, so this really tells if "chassis_nr" is present > > + * or not. > > + */ > > + if (!chassis_nr) { > > + error_setg(errp, "PCI Bridge lacks a \"chassis_nr\" property"); > > + error_append_hint(errp, "Try -device pci-bridge instead.\n"); > > + return false; > > + } > > + > > + /* We want unique values for "chassis_nr" */ > > + if (object_child_foreach_recursive(object_get_root(), check_chassis_nr, > > + bridge)) { > > + error_setg(errp, "Bridge chassis %d already in use", chassis_nr); > > + return false; > > + } > > + > > + return true; > > +} > > + > > static void spapr_pci_plug(HotplugHandler *plug_handler, > > DeviceState *plugged_dev, Error **errp) > > { > > @@ -1491,6 +1542,12 @@ static void spapr_pci_plug(HotplugHandler *plug_handler, > > PCIBus *bus = PCI_BUS(qdev_get_parent_bus(DEVICE(pdev))); > > uint32_t slotnr = PCI_SLOT(pdev->devfn); > > > > + if (pc->is_bridge) { > > + if (!bridge_has_valid_chassis_nr(OBJECT(plugged_dev), errp)) { > > + return; > > + } > > + } > > + > > > Add a comment here explaning DRC ids are generated from chassis_nr and > these need to be unique? > Makes sense. > > > /* if DR is disabled we don't need to do anything in the case of > > * hotplug or coldplug callbacks > > */ > > > > With above fixed: > > Acked-by: Michael S. Tsirkin > > Feel free to merge. > Thanks !