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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 98B4AC10F27 for ; Tue, 10 Mar 2020 12:26:32 +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 6C81524655 for ; Tue, 10 Mar 2020 12:26:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C81524655 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]:59724 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jBdxv-0000dj-GP for qemu-devel@archiver.kernel.org; Tue, 10 Mar 2020 08:26:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49188) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jBdwc-0008Ni-CG for qemu-devel@nongnu.org; Tue, 10 Mar 2020 08:25:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jBdwa-0004Qh-LM for qemu-devel@nongnu.org; Tue, 10 Mar 2020 08:25:10 -0400 Received: from 2.mo177.mail-out.ovh.net ([178.33.109.80]:50717) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jBdwa-00048s-EP for qemu-devel@nongnu.org; Tue, 10 Mar 2020 08:25:08 -0400 Received: from player772.ha.ovh.net (unknown [10.108.35.197]) by mo177.mail-out.ovh.net (Postfix) with ESMTP id F0C71127959 for ; Tue, 10 Mar 2020 13:25:05 +0100 (CET) Received: from kaod.org (lns-bzn-46-82-253-208-248.adsl.proxad.net [82.253.208.248]) (Authenticated sender: groug@kaod.org) by player772.ha.ovh.net (Postfix) with ESMTPSA id AF46B104FA79B; Tue, 10 Mar 2020 12:24:52 +0000 (UTC) Date: Tue, 10 Mar 2020 13:24:50 +0100 From: Greg Kurz To: "Michael S. Tsirkin" Subject: Re: [PATCH v3 1/2] spapr: Disable legacy virtio devices for pseries-5.0 and later Message-ID: <20200310132450.603ac70c@bahia.home> In-Reply-To: <20200310065901-mutt-send-email-mst@kernel.org> References: <20200305043009.611636-1-david@gibson.dropbear.id.au> <20200305043009.611636-2-david@gibson.dropbear.id.au> <20200305113146.6850f04b@bahia.home> <20200310104329.3dd232d2@bahia.home> <20200310065901-mutt-send-email-mst@kernel.org> 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=UTF-8 Content-Transfer-Encoding: quoted-printable X-Ovh-Tracer-Id: 9737063873581521369 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedugedruddvtddgfeelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvffukfgjfhfogggtgfesthhqredtredtjeenucfhrhhomhepifhrvghgucfmuhhriicuoehgrhhouhhgsehkrghougdrohhrgheqnecukfhppedtrddtrddtrddtpdekvddrvdehfedrvddtkedrvdegkeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhhouggvpehsmhhtphdqohhuthdphhgvlhhopehplhgrhigvrhejjedvrdhhrgdrohhvhhdrnhgvthdpihhnvghtpedtrddtrddtrddtpdhmrghilhhfrhhomhepghhrohhugheskhgrohgurdhorhhgpdhrtghpthhtohepqhgvmhhuqdguvghvvghlsehnohhnghhnuhdrohhrgh X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 178.33.109.80 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: pair@us.ibm.com, aik@ozlabs.ru, qemu-devel@nongnu.org, paulus@samba.org, clg@kaod.org, mdroth@us.ibm.com, qemu-ppc@nongnu.org, David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 10 Mar 2020 07:03:34 -0400 "Michael S. Tsirkin" wrote: > On Tue, Mar 10, 2020 at 10:43:29AM +0100, Greg Kurz wrote: > > On Thu, 5 Mar 2020 11:31:46 +0100 > > Greg Kurz wrote: > >=20 > > > On Thu, 5 Mar 2020 15:30:08 +1100 > > > David Gibson wrote: > > >=20 > > > > PAPR specifies a kind of odd, paravirtualized PCI bus, which looks = to > > > > the guess mostly like classic PCI, even if some of the individual > > > > devices on the bus are PCI Express. One consequence of that is that > > > > virtio-pci devices still default to being in transitional mode, tho= ugh > > > > legacy mode is now disabled by default on current q35 x86 machine > > > > types. > > > >=20 > > > > Legacy mode virtio devices aren't really necessary any more, and are > > > > causing some problems for future changes. Therefore, for the > > > > pseries-5.0 machine type (and onwards), switch to modern-only > > > > virtio-pci devices by default. > > > >=20 > > > > This does mean we no longer support guest kernels prior to 4.0, unl= ess > > > > they have modern virtio support backported (which some distro kerne= ls > > > > like that in RHEL7 do). > > > >=20 > > > > Signed-off-by: David Gibson > > > > --- > > >=20 > > > Reviewed-by: Greg Kurz > > >=20 > > > FWIW, I could test the following: > > > - allows a RHEL7 guest with pre 4.0 kernel to boot, as mentioned > > > in the changelog > > > - breaks boot of older RHEL 6.10 guests as expected > > > - allows migration of older machine types to/from QEMU 4.2 > > >=20 > > > Tested-by: Greg Kurz > > >=20 > >=20 > > Wait... I gave a try to virtiofsd and there's a problem: > >=20 > > $ ./ppc64-softmmu/qemu-system-ppc64 -device vhost-user-fs-pci > > Unexpected error in object_property_find() at /home/greg/Work/qemu/qemu= -ppc/qom/object.c:1231: > > qemu-system-ppc64: -device vhost-user-fs-pci: can't apply global virtio= -pci.disable-legacy=3Don: Property '.disable-legacy' not found > > Aborted (core dumped) > >=20 > > It is still not possible to set the disable-legacy prop on the > > vhost-user-fs-pci device, even without this patch, but QEMU > > doesn't abort: > >=20 > > $ ./ppc64-softmmu/qemu-system-ppc64 -device vhost-user-fs-pci -global v= irtio-pci.disable-legacy=3Don > > qemu-system-ppc64: -device vhost-user-fs-pci: can't apply global virtio= -pci.disable-legacy=3Don: Property '.disable-legacy' not found > > $ > >=20 > > It seems to be related to the fact that vhost-user-fs-pci is a non-tran= sitional > > only device, as shown with this workaround: > >=20 > > --- a/hw/ppc/spapr.c > > +++ b/hw/ppc/spapr.c > > @@ -4574,7 +4574,7 @@ static void spapr_machine_latest_class_options(Ma= chineClass *mc) > > * class since it doesn't have a compat_props. > > */ > > static GlobalProperty compat[] =3D { > > - { TYPE_VIRTIO_PCI, "disable-legacy", "on", }, > > + { TYPE_VIRTIO_PCI "-transitional", "disable-legacy", "on", }, > > }; > > =20 > > mc->alias =3D "pseries"; >=20 > Does this actually help? There's no type virtio-pci-transitional, is > there? >=20 Oops you're right. There's no such type and it doesn't help in the end... I should have tried that with -global before posting -global virtio-pci-transitional.disable-legacy=3Don qemu-system-ppc64: warning: global virtio-pci-transitional.disable-legacy h= as invalid class name Maybe worth adding a warning as well when done from the machine code, but this is another story. Sorry for the noise. > >=20 > > but there's probably a better way to address this. > >=20 > > MST, Any suggestion ? >=20 > Hmm I'm not sure how to fix this properly. The only idea that comes > to mind is a new internal-only "x-disable-legacy" that would be on virtio= -pci, > duplicating functionality of disable-legacy but intended for > globals like this. >=20 Maybe but Daniel P. Berrang=C3=A9 jumped in and has some arguments against what we're trying to achieve with this series... A suivre. >=20 >=20 > > > > hw/ppc/spapr.c | 17 +++++++++++++++++ > > > > 1 file changed, 17 insertions(+) > > > >=20 > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > > > index 2eb0d8f70d..3cfc98ac61 100644 > > > > --- a/hw/ppc/spapr.c > > > > +++ b/hw/ppc/spapr.c > > > > @@ -65,6 +65,7 @@ > > > > =20 > > > > #include "hw/pci/pci.h" > > > > #include "hw/scsi/scsi.h" > > > > +#include "hw/virtio/virtio-pci.h" > > > > #include "hw/virtio/virtio-scsi.h" > > > > #include "hw/virtio/vhost-scsi-common.h" > > > > =20 > > > > @@ -4566,8 +4567,20 @@ static const TypeInfo spapr_machine_info =3D= { > > > > =20 > > > > static void spapr_machine_latest_class_options(MachineClass *mc) > > > > { > > > > + /* > > > > + * Most defaults for the latest behaviour are inherited from t= he > > > > + * base class, but we need to override the (non ppc specific) > > > > + * default behaviour for virtio. We can't do that from the ba= se > > > > + * class since it doesn't have a compat_props. > > > > + */ > > > > + static GlobalProperty compat[] =3D { > > > > + { TYPE_VIRTIO_PCI, "disable-legacy", "on", }, > > > > + }; > > > > + > > > > mc->alias =3D "pseries"; > > > > mc->is_default =3D true; > > > > + > > > > + compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat= )); > > > > } > > > > =20 > > > > #define DEFINE_SPAPR_MACHINE(suffix, verstr, latest) = \ > > > > @@ -4607,6 +4620,9 @@ DEFINE_SPAPR_MACHINE(5_0, "5.0", true); > > > > static void spapr_machine_4_2_class_options(MachineClass *mc) > > > > { > > > > SpaprMachineClass *smc =3D SPAPR_MACHINE_CLASS(mc); > > > > + static GlobalProperty compat[] =3D { > > > > + { TYPE_VIRTIO_PCI, "disable-legacy", "auto" }, > > > > + }; > > > > =20 > > > > spapr_machine_5_0_class_options(mc); > > > > compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_= 2_len); > > > > @@ -4614,6 +4630,7 @@ static void spapr_machine_4_2_class_options(M= achineClass *mc) > > > > smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] =3D SPAPR_CAP_OFF; > > > > smc->rma_limit =3D 16 * GiB; > > > > mc->nvdimm_supported =3D false; > > > > + compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat= )); > > > > } > > > > =20 > > > > DEFINE_SPAPR_MACHINE(4_2, "4.2", false); > > >=20 >=20