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=-8.3 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 D62F6C3F2D1 for ; Thu, 5 Mar 2020 10:33:15 +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 ABF2F21556 for ; Thu, 5 Mar 2020 10:33:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABF2F21556 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]:46760 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9noY-00086p-Ts for qemu-devel@archiver.kernel.org; Thu, 05 Mar 2020 05:33:14 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46409) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9nnU-0007G6-BZ for qemu-devel@nongnu.org; Thu, 05 Mar 2020 05:32:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j9nnT-00054A-1M for qemu-devel@nongnu.org; Thu, 05 Mar 2020 05:32:08 -0500 Received: from 2.mo69.mail-out.ovh.net ([178.33.251.80]:54869) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j9nnS-00050V-RD for qemu-devel@nongnu.org; Thu, 05 Mar 2020 05:32:06 -0500 Received: from player788.ha.ovh.net (unknown [10.108.54.52]) by mo69.mail-out.ovh.net (Postfix) with ESMTP id DF462877AA for ; Thu, 5 Mar 2020 11:32:02 +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 player788.ha.ovh.net (Postfix) with ESMTPSA id C7B35101DCD5A; Thu, 5 Mar 2020 10:31:53 +0000 (UTC) Date: Thu, 5 Mar 2020 11:31:46 +0100 From: Greg Kurz To: David Gibson Subject: Re: [PATCH v3 1/2] spapr: Disable legacy virtio devices for pseries-5.0 and later Message-ID: <20200305113146.6850f04b@bahia.home> In-Reply-To: <20200305043009.611636-2-david@gibson.dropbear.id.au> References: <20200305043009.611636-1-david@gibson.dropbear.id.au> <20200305043009.611636-2-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: 15357837682151823846 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedugedruddutddgudekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvffukfgjfhfogggtgfesthejredtredtvdenucfhrhhomhepifhrvghgucfmuhhriicuoehgrhhouhhgsehkrghougdrohhrgheqnecukfhppedtrddtrddtrddtpdekvddrvdehfedrvddtkedrvdegkeenucevlhhushhtvghrufhiiigvpedunecurfgrrhgrmhepmhhouggvpehsmhhtphdqohhuthdphhgvlhhopehplhgrhigvrhejkeekrdhhrgdrohhvhhdrnhgvthdpihhnvghtpedtrddtrddtrddtpdhmrghilhhfrhhomhepghhrohhugheskhgrohgurdhorhhgpdhrtghpthhtohepqhgvmhhuqdguvghvvghlsehnohhnghhnuhdrohhrgh X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 178.33.251.80 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, mst@redhat.com, aik@ozlabs.ru, qemu-devel@nongnu.org, paulus@samba.org, clg@kaod.org, mdroth@us.ibm.com, qemu-ppc@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 5 Mar 2020 15:30:08 +1100 David Gibson wrote: > 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, though > legacy mode is now disabled by default on current q35 x86 machine > types. > > 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. > > This does mean we no longer support guest kernels prior to 4.0, unless > they have modern virtio support backported (which some distro kernels > like that in RHEL7 do). > > Signed-off-by: David Gibson > --- Reviewed-by: Greg Kurz 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 Tested-by: Greg Kurz > hw/ppc/spapr.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > 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 @@ > > #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" > > @@ -4566,8 +4567,20 @@ static const TypeInfo spapr_machine_info = { > > static void spapr_machine_latest_class_options(MachineClass *mc) > { > + /* > + * Most defaults for the latest behaviour are inherited from the > + * base class, but we need to override the (non ppc specific) > + * default behaviour for virtio. We can't do that from the base > + * class since it doesn't have a compat_props. > + */ > + static GlobalProperty compat[] = { > + { TYPE_VIRTIO_PCI, "disable-legacy", "on", }, > + }; > + > mc->alias = "pseries"; > mc->is_default = true; > + > + compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat)); > } > > #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 = SPAPR_MACHINE_CLASS(mc); > + static GlobalProperty compat[] = { > + { TYPE_VIRTIO_PCI, "disable-legacy", "auto" }, > + }; > > 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(MachineClass *mc) > smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF; > smc->rma_limit = 16 * GiB; > mc->nvdimm_supported = false; > + compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat)); > } > > DEFINE_SPAPR_MACHINE(4_2, "4.2", false);