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 A8B9BC25B06 for ; Mon, 15 Aug 2022 02:41:20 +0000 (UTC) Received: from localhost ([::1]:55448 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oNQ2Z-0003WX-9C for qemu-devel@archiver.kernel.org; Sun, 14 Aug 2022 22:41:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46182) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oNPzL-0001HH-JW; Sun, 14 Aug 2022 22:38:00 -0400 Received: from mail.ozlabs.org ([2404:9400:2221:ea00::3]:39547 helo=gandalf.ozlabs.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oNPzI-0001HZ-2n; Sun, 14 Aug 2022 22:37:59 -0400 Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4M5djk3Wtzz4xV3; Mon, 15 Aug 2022 12:37:46 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=201602; t=1660531066; bh=CwFL05aon2HlzNjTpkWJWYU882XSQa8y5pieoFIkQxQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X3BIu8NlYuP/PnvIUIM3h1pK83HfB/wHZdLBwOA6avkPUZgs8wTrCJPzf/LFTmySe 6t/AJz9i+heuozbhM4NhCnlz5+e1qQ5VDVziid7mPYxzmSLnQ8NYKH7OYrR/aqA796 oZM7+sK8KXe3U3rds3VWqD9oZROVInJ09G2d3eSk= Date: Mon, 15 Aug 2022 12:37:39 +1000 From: David Gibson To: Daniel Henrique Barboza Cc: qemu-devel@nongnu.org, alistair.francis@wdc.com, =?iso-8859-1?Q?C=E9dric?= Le Goater , qemu-ppc@nongnu.org Subject: Re: [PATCH for-7.2 v2 10/20] hw/ppc: set machine->fdt in spapr machine Message-ID: References: <20220805093948.82561-1-danielhb413@gmail.com> <20220805093948.82561-11-danielhb413@gmail.com> <1991166b-a463-4812-a6fe-eae5299fc3f1@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RPnrDEGYqcOxws4W" Content-Disposition: inline In-Reply-To: <1991166b-a463-4812-a6fe-eae5299fc3f1@gmail.com> Received-SPF: pass client-ip=2404:9400:2221:ea00::3; envelope-from=dgibson@gandalf.ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --RPnrDEGYqcOxws4W Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Aug 12, 2022 at 07:23:09PM -0300, Daniel Henrique Barboza wrote: >=20 >=20 > On 8/8/22 00:26, David Gibson wrote: > > On Fri, Aug 05, 2022 at 06:39:38AM -0300, Daniel Henrique Barboza wrote: > > > The pSeries machine never bothered with the common machine->fdt > > > attribute. We do all the FDT related work using spapr->fdt_blob. > > >=20 > > > We're going to introduce HMP commands to read and save the FDT, which > > > will rely on setting machine->fdt properly to work across all machine > > > archs/types. > > >=20 > > > Let's set machine->fdt in the two places where we manipulate the FDT: > > > spapr_machine_reset() and CAS. spapr->fdt_blob is left untouched: what > > > we want is a way to access the FDT from HMP, not replace > > > spapr->fdt_blob. > >=20 > > Given there is now an fdt field in the generic MACHINE structure, we > > should be able to remove the one in spapr->fdt_blob, yes? >=20 > I thought about it but I backed down when I realized that spapr->fdt_blob= is > being migrated. >=20 > At first glance it would be a matter of migrating ms->fdt and then removi= ng > spapr->fdt_blob, but then I got confused about how a migration to an older > version would occur (e.g. QEMU 7.2 with ms->fdt to a QEMU 7.0 with > spapr->fdt_blob). >=20 > Migration to a newer QEMU would require us to move the spapr->version_id = to 4 > and then handle the old version accordingly in spapr_post_load(). >=20 > Probably something to think about after this work is accepted. Fair enough. I'm confident the migration semantics can be worked out, but it will require some care. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --RPnrDEGYqcOxws4W Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEoULxWu4/Ws0dB+XtgypY4gEwYSIFAmL5sWwACgkQgypY4gEw YSJm4A//bH9c7q508FW6w1+tkQihu0ppSQC/5AUjjKpmgBH6INv+QqmqV4scIsID cOSejgorBBr45BWHvQkAmwOVTxiv8qIiZ9CIXwJHnTvxZTqRuF+ifgXCFvd+iYAw Wx/AW1tgWJ3657RBAtMAKCMBSUKi/SHoROWXTFFlFaGZlz1aW1ePDlfgnY5eZPtK gVT7+FTjodz1wkduWAYun4nrP4n4y52/+jDORhpXwEhOgNnZ3ae3W7qHWsYqGHhO wX0KlC/h39tIbZCmJVZIJVuxCifkLyxiCIo2GQ847M4aPYcmVSt7pY/3qRUR9m6E ipG3hOmclqeEpNSeokGlBAhTOeYrWZm3fcUo6ysmXxuLfilMJjE9liVKSMNYaMtK /oGCJrWI5F0qLMJRM3NK22WoG/eKgRQMg1notD8dwRYWvJu1+CssmIwJZJukDNyI Xjft+x279f2Yb7BFDfAs3ZgcXR9WiyjFNR6uqf1c+zB6I5HXxV0zk4rrLFSFohqP x+TGpJqipw/wqisB8y+nRDEpszp801bI+4VUZVuFuQw2N+9763zocyKSDBv+EInN x8oRfGpVvAEWTaEBzf+KSm/53K05XsSPYnJj5wBOca217fVKDjFr3vXfryDm5fJI IrHTx0ZVIxHFMd7uIjuYEo//HNYDnDlMaKVWjW93NtqkE9m28zA= =/qra -----END PGP SIGNATURE----- --RPnrDEGYqcOxws4W--