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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 CA0C9C432C0 for ; Tue, 19 Nov 2019 01:03:18 +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 7F96522310 for ; Tue, 19 Nov 2019 01:03:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="Iy22A/3S" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F96522310 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40836 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iWruB-0007Oc-1j for qemu-devel@archiver.kernel.org; Mon, 18 Nov 2019 20:02:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:60894) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iWrsX-0006pQ-KV for qemu-devel@nongnu.org; Mon, 18 Nov 2019 20:00:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iWrsW-0001qY-Dv for qemu-devel@nongnu.org; Mon, 18 Nov 2019 20:00:25 -0500 Received: from ozlabs.org ([203.11.71.1]:56115) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iWrsW-0001oz-2A; Mon, 18 Nov 2019 20:00:24 -0500 Received: by ozlabs.org (Postfix, from userid 1007) id 47H6tq5YhSz9sPV; Tue, 19 Nov 2019 12:00:19 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1574125219; bh=PsSDjfi61zbflZICabmIrHcXIAPqJQq/L2+4OMfn2nE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Iy22A/3Sc4EJUbGUcrcTMHXfDTWA15hJvKZ/ssM3vhx+BZ6KGDfSIrMDQyYjg+XT5 V3aVJmyMm8w226k1Ewi+O1tQaBpaWgoWTqSXrzZdau1uIMC4GuT0IFBex6lFVN9YpA MbLtUGWqwID/p1A3mwS2JxEmp5VDzs6+689lra0Y= Date: Tue, 19 Nov 2019 12:00:12 +1100 From: David Gibson To: Greg Kurz Subject: Re: [PATCH] spapr: Fix VSMT mode when it is not supported by the kernel Message-ID: <20191119010012.GI5582@umbus.fritz.box> References: <20191108154035.12913-1-lvivier@redhat.com> <20191108174759.2d4040f1@bahia.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Az4VpBrmI9+OyhK/" Content-Disposition: inline In-Reply-To: <20191108174759.2d4040f1@bahia.lan> User-Agent: Mutt/1.12.1 (2019-06-15) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 203.11.71.1 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: Laurent Vivier , =?utf-8?B?THVrw6HFoQ==?= Doktor , Juan Quintela , qemu-devel@nongnu.org, "Dr . David Alan Gilbert" , qemu-ppc@nongnu.org, clg@kaod.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --Az4VpBrmI9+OyhK/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Nov 08, 2019 at 05:47:59PM +0100, Greg Kurz wrote: > On Fri, 8 Nov 2019 16:40:35 +0100 > Laurent Vivier wrote: >=20 > > Commit 29cb4187497d sets by default the VSMT to smp_threads, > > but older kernels (< 4.13) don't support that. > >=20 > > We can reasonably restore previous behavior with this kernel > > to allow to run QEMU as before. > >=20 > > If VSMT is not supported, VSMT will be set to MAX(8, smp_threads) > > as it is done for previous machine types (< pseries-4.2) > >=20 >=20 > It is usually _bad_ to base the machine behavior on host capabilities. > What happens if we migrate between an older kernel and a recent one ? Right. We're really trying to remove instaces of such behaviour. I'd prefer to completely revert Greg's original patch than to re-introduce host configuration dependency into the guest configuration.. > I understand this is to fix tests/migration-test on older kernels. > Couldn't this be achieved with migration-test doing some introspection > and maybe pass vsmt=3D8 on the QEMU command line ? =2E.adjusting the test case like this might be a better idea, though. What's the test setup where we're using the old kernel? I really only applied the original patch on the guess that we didn't really care about kernels that old. The fact you've hit this in practice makes me doubt that assumption. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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