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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 9D504C47404 for ; Fri, 11 Oct 2019 06:16:59 +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 6D72D21D56 for ; Fri, 11 Oct 2019 06:16:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D72D21D56 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]:46204 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIoEU-0006gS-H4 for qemu-devel@archiver.kernel.org; Fri, 11 Oct 2019 02:16:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51224) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIoBU-0005C0-1e for qemu-devel@nongnu.org; Fri, 11 Oct 2019 02:13:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIoBS-0005Hc-5W for qemu-devel@nongnu.org; Fri, 11 Oct 2019 02:13:51 -0400 Received: from 7.mo3.mail-out.ovh.net ([46.105.57.200]:39888) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIoBR-0005GH-RX for qemu-devel@nongnu.org; Fri, 11 Oct 2019 02:13:50 -0400 Received: from player158.ha.ovh.net (unknown [10.109.159.136]) by mo3.mail-out.ovh.net (Postfix) with ESMTP id 1753A22AF89 for ; Fri, 11 Oct 2019 08:13:46 +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 player158.ha.ovh.net (Postfix) with ESMTPSA id 4BA4AABC9DEC; Fri, 11 Oct 2019 06:13:36 +0000 (UTC) Date: Fri, 11 Oct 2019 08:13:33 +0200 From: Greg Kurz To: David Gibson Subject: Re: [PATCH v4 17/19] spapr: Remove last pieces of SpaprIrq Message-ID: <20191011081333.7e483b95@bahia.lan> In-Reply-To: <20191011050758.GD4080@umbus.fritz.box> References: <20191009060818.29719-1-david@gibson.dropbear.id.au> <20191009060818.29719-18-david@gibson.dropbear.id.au> <20191009190215.7e05c017@bahia.lan> <20191010020209.GC28552@umbus.fritz.box> <20191010082958.12e17561@bahia.lan> <20191010223304.0cf7ccd3@bahia.lan> <20191011050758.GD4080@umbus.fritz.box> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/ghqjTh.5k_SClLD=UllshU9"; protocol="application/pgp-signature"; micalg=pgp-sha256 X-Ovh-Tracer-Id: 2133017377574787558 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedufedrieeggddutdeiucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 46.105.57.200 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: Jason Wang , Riku Voipio , qemu-devel@nongnu.org, qemu-ppc@nongnu.org, clg@kaod.org, Paolo Bonzini , =?UTF-8?B?TWFy?= =?UTF-8?B?Yy1BbmRyw6k=?= Lureau , philmd@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --Sig_/ghqjTh.5k_SClLD=UllshU9 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 11 Oct 2019 16:07:58 +1100 David Gibson wrote: > On Thu, Oct 10, 2019 at 10:33:04PM +0200, Greg Kurz wrote: > > On Thu, 10 Oct 2019 08:29:58 +0200 > > Greg Kurz wrote: > >=20 > > > On Thu, 10 Oct 2019 13:02:09 +1100 > > > David Gibson wrote: > > >=20 > > > > On Wed, Oct 09, 2019 at 07:02:15PM +0200, Greg Kurz wrote: > > > > > On Wed, 9 Oct 2019 17:08:16 +1100 > > > > > David Gibson wrote: > > > > >=20 > > > > > > The only thing remaining in this structure are the flags to all= ow either > > > > > > XICS or XIVE to be present. These actually make more sense as = spapr > > > > > > capabilities - that way they can take advantage of the existing > > > > > > infrastructure to sanity check capability states across migrati= on and so > > > > > > forth. > > > > > >=20 > > > > >=20 > > > > > The user can now choose the interrupt controller mode either thro= ugh > > > > > ic-mode or through cap-xics/cap-xive. I guess it doesn't break an= ything > > > > > to expose another API to do the same thing but it raises some que= stions. > > > > >=20 > > > > > We should at least document somewhere that ic-mode is an alias to= these > > > > > caps, and maybe state which is the preferred method (I personally= vote > > > > > for the caps). > > > > >=20 > > > > > Also, we must keep ic-mode for the moment to stay compatible with= the > > > > > existing pseries-4.0 and pseries-4.1 machine types, but will we > > > > > keep ic-mode forever ? If no, maybe start by not allowing it for > > > > > pseries-4.2 ? > > > >=20 > > > > I'm actually inclined to keep it for now, maybe even leave it as the > > > > suggested way to configure this. The caps are nice from an internal > > > > organization point of view, but ic-mode is arguably a more user > > > > friendly way of configuring it. The conversion of one to the other= is > > > > straightforward, isolated ans small, so I'm not especially bothered= by > > > > keeping it around. > > > >=20 > > >=20 > > > Fair enough. > > >=20 > > > Reviewed-by: Greg Kurz > > >=20 > >=20 > > But unfortunately this still requires care :-\ > >=20 > > qemu-system-ppc64: cap-xive higher level (1) in incoming stream than on= destination (0) > > qemu-system-ppc64: error while loading state for instance 0x0 of device= 'spapr' > > qemu-system-ppc64: load of migration failed: Invalid argument > >=20 > > or > >=20 > > qemu-system-ppc64: cap-xics higher level (1) in incoming stream than on= destination (0) > > qemu-system-ppc64: error while loading state for instance 0x0 of device= 'spapr' > > qemu-system-ppc64: load of migration failed: Invalid argument > >=20 > > when migrating from QEMU 4.1 with ic-mode=3Dxics and ic-mode=3Dxive res= pectively. > >=20 > > This happens because the existing pseries-4.1 machine type doesn't send= the > > new caps and the logic in spapr_caps_post_migration() wrongly assumes t= hat > > the source has both caps set: > >=20 > > srccaps =3D default_caps_with_cpu(spapr, MACHINE(spapr)->cpu_type); > > for (i =3D 0; i < SPAPR_CAP_NUM; i++) { > > /* If not default value then assume came in with the migration = */ > > if (spapr->mig.caps[i] !=3D spapr->def.caps[i]) { > >=20 > > spapr->mig.caps[SPAPR_CAP_XICS] =3D 0 > > spapr->mig.caps[SPAPR_CAP_XIVE] =3D 0 > >=20 > > srccaps.caps[i] =3D spapr->mig.caps[i]; > >=20 > > srcaps.caps[SPAPR_CAP_XICS] =3D 1 > > srcaps.caps[SPAPR_CAP_XIVE] =3D 1 > >=20 > > } > > } > >=20 > > and breaks > >=20 > > for (i =3D 0; i < SPAPR_CAP_NUM; i++) { > > SpaprCapabilityInfo *info =3D &capability_table[i]; > >=20 > > if (srccaps.caps[i] > dstcaps.caps[i]) { > >=20 > > srcaps.caps[SPAPR_CAP_XICS] =3D 0 when ic-mode=3Dxive > > srcaps.caps[SPAPR_CAP_XIVE] =3D 0 when ic-mode=3Dxics > >=20 > > error_report("cap-%s higher level (%d) in incoming stream t= han on destination (%d)", > > info->name, srccaps.caps[i], dstcaps.caps[i]); > > ok =3D false; > > } >=20 > Ah.. right. I thought there would be problems with backwards > migration, but I didn't think of this problem even with forward > migration. >=20 > > Maybe we shouldn't check capabilities that we know the source > > isn't supposed to send, eg. by having a smc->max_cap ? >=20 > Uh.. I'm not really sure what exactly you're suggesting here. >=20 I'm suggesting to have a per-machine version smc->max_cap that contains the highest supported cap index, to be used instead of SPAPR_CAP_NUM in this functions, ie. for (i =3D 0; i <=3D smc->max_cap; i++) { ... } where we would have smc->max_cap =3D SPAPR_CAP_CCF_ASSIST for pseries-4.1 and smc->max_cap =3D SPAPR_CAP_XIVE for psereis-4.2 > I think what we need here is a custom migrate_needed function, like we > already have for cap_hpt_maxpagesize, to exclude it from the migration > stream for machine versions before 4.2. >=20 No, VMState needed() hooks are for outgoing migration only. bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque) { if (vmsd->needed && !vmsd->needed(opaque)) { /* optional section not needed */ return false; } return true; } --Sig_/ghqjTh.5k_SClLD=UllshU9 Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEtIKLr5QxQM7yo0kQcdTV5YIvc9YFAl2gHY0ACgkQcdTV5YIv c9ZoVxAAlXJRk6ZLeugfdaYf03TOIbF2+ApR9N4MwUXzOpAVp4oBwA79gZ7azknf wZI0thMinS38HkPZA/wRhCUvUaOwPhVNvdWKpFYU6ypyE47RMDI0QsYH2HPg8in9 JAlzlGJlk49biXXK1K2/XTLCqYUSb282KhTvDoZV7ZXpLBlUD68FzoJgfRpd/px2 xzCUaG4euW5o51OVwCJyXecoNazl291bz9IhYQYjn5sTUtZqHG/uhKGbTXOSdqG+ dm6Vtdq3ZyMb6jiVeBzChKpZ3Lu1CXgqaVnatwy0bHM4v6oIm5zKp3ZXNcgco06o bYnQvXvpAnvv44wje4jbs5SbuCeYmayG8/RSfevd1IUeJyUpIoyJTTHqVrpYUOD9 1Xr715qrPlkX/js/pcxAlWu5/SSpkoYs5rpQbcpQcnWi3LLlIvRm0zOvPasRBF4m ST0c3/PJ0K2hRgULQScxGF4F+DxD5sU0Z5Jzc5sOwGQkEvNQECJdpeewiitrMiSS at1NmWVHwdl1syspGRwOFNnGt4sU17rtq3A/+wzvYuJNnw+UYSDuh4BD2VGJlEVs IBlN8ov/pvVwYRla+YVa8dedGg2pGn8QmJtiJvKHKNimRmftq444F2B8llXMiUvq kIHqmU6SF+lNi0w4FIlV7VYulavE2n7W1jaco4nJcxpZmj81thg= =QDFp -----END PGP SIGNATURE----- --Sig_/ghqjTh.5k_SClLD=UllshU9--