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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C4402C433F5 for ; Fri, 7 Jan 2022 13:42:18 +0000 (UTC) Received: from localhost ([::1]:39352 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n5pVZ-0001ya-Ba for qemu-devel@archiver.kernel.org; Fri, 07 Jan 2022 08:42:17 -0500 Received: from eggs.gnu.org ([209.51.188.92]:49738) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n5pSt-0007xI-An for qemu-devel@nongnu.org; Fri, 07 Jan 2022 08:39:31 -0500 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:54720) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n5pSr-0003nn-Ef for qemu-devel@nongnu.org; Fri, 07 Jan 2022 08:39:30 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-554-PkbWxOoyO3SF68-DqCQ6Yg-1; Fri, 07 Jan 2022 08:39:15 -0500 X-MC-Unique: PkbWxOoyO3SF68-DqCQ6Yg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 687D9835E22; Fri, 7 Jan 2022 13:39:14 +0000 (UTC) Received: from bahia (unknown [10.39.192.66]) by smtp.corp.redhat.com (Postfix) with ESMTP id 680731079F3B; Fri, 7 Jan 2022 13:39:12 +0000 (UTC) Date: Fri, 7 Jan 2022 14:39:10 +0100 From: Greg Kurz To: David Gibson Subject: Re: [PATCH qemu] spapr: Force 32bit when resetting a core Message-ID: <20220107143910.4443af02@bahia> In-Reply-To: References: <20220107072423.2278113-1-aik@ozlabs.ru> <20220107125747.7ddfd3a0@bahia> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/MwlwzU26/whg+dKa7ieas5i"; protocol="application/pgp-signature"; micalg=pgp-sha256 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Received-SPF: softfail client-ip=205.139.111.44; envelope-from=groug@kaod.org; helo=us-smtp-delivery-44.mimecast.com 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_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexey Kardashevskiy , Daniel Henrique Barboza , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, =?UTF-8?B?Q8OpZHJpYw==?= Le Goater Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --Sig_/MwlwzU26/whg+dKa7ieas5i Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 7 Jan 2022 23:19:03 +1100 David Gibson wrote: > On Fri, Jan 07, 2022 at 12:57:47PM +0100, Greg Kurz wrote: > > On Fri, 7 Jan 2022 18:24:23 +1100 > > Alexey Kardashevskiy wrote: > >=20 > > > "PowerPC Processor binding to IEEE 1275" says in > > > "8.2.1. Initial Register Values" that the initial state is defined as > > > 32bit so do it for both SLOF and VOF. > > >=20 > > > This should not cause behavioral change as SLOF switches to 64bit very > > > early anyway.=20 > >=20 > > Only one CPU goes through SLOF. What about the other ones, including > > hot plugged CPUs ? >=20 > Those will be started by the start-cpu RTAS call which has its own > semantics. >=20 Ah indeed, there's code in linux/arch/powerpc/kernel/head_64.S to switch secondaries to 64bit... but then, as noted by Cedric, ppc_cpu_reset(), which is called earlier sets MSR_SF but the changelog of commit 8b9f2118ca40 doesn't provide much details on the motivation. 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