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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 75388C43331 for ; Fri, 27 Mar 2020 16:47:27 +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 417BD20857 for ; Fri, 27 Mar 2020 16:47:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="AAeMpQRC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 417BD20857 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44386 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jHs8k-0006hM-ES for qemu-devel@archiver.kernel.org; Fri, 27 Mar 2020 12:47:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47950) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jHs7u-0006HA-5e for qemu-devel@nongnu.org; Fri, 27 Mar 2020 12:46:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jHs7s-00072P-OU for qemu-devel@nongnu.org; Fri, 27 Mar 2020 12:46:33 -0400 Received: from us-smtp-delivery-74.mimecast.com ([216.205.24.74]:25913) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jHs7s-0006vt-Jw for qemu-devel@nongnu.org; Fri, 27 Mar 2020 12:46:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585327591; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WrvWjEVAogqGLXAVUnUNcFoDwPHvVTSNWLcFCDUMuag=; b=AAeMpQRCjv8Df6xDWA4iEcxnR5lK6upUuCkOAsIMFHQvODMDj3lmM7VfZSLuc4zg9wMs0X LDL1Wp34FWDpCQQ52liBxOUI813rkVvoC1HAQOvOvsFmirhlox0OSsvh6O+JVtARBge0yi w+xPngZUsxwGl9WC+JYmEDW1/J2aQCg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-265-NnruVez9MZqd8O2jTd5OkA-1; Fri, 27 Mar 2020 12:46:30 -0400 X-MC-Unique: NnruVez9MZqd8O2jTd5OkA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A89B3800D4E; Fri, 27 Mar 2020 16:46:28 +0000 (UTC) Received: from localhost (unknown [10.40.208.76]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8E1385E02B; Fri, 27 Mar 2020 16:46:22 +0000 (UTC) Date: Fri, 27 Mar 2020 17:46:20 +0100 From: Igor Mammedov To: Christian Borntraeger Subject: Re: [PATCH v1] s390x: Reject unaligned RAM sizes Message-ID: <20200327174620.06b9c324@redhat.com> In-Reply-To: <24681aa0-9053-238f-89da-8ce08d34241d@de.ibm.com> References: <20200327152930.66636-1-david@redhat.com> <64cefab8-f1e0-fbc7-27d3-4f28758c595a@de.ibm.com> <24681aa0-9053-238f-89da-8ce08d34241d@de.ibm.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 216.205.24.74 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: =?UTF-8?B?THVrw6HFoQ==?= Doktor , Thomas Huth , Janosch Frank , David Hildenbrand , Cornelia Huck , Richard Henderson , qemu-devel@nongnu.org, "Dr . David Alan Gilbert" , Halil Pasic , qemu-s390x@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 27 Mar 2020 17:05:34 +0100 Christian Borntraeger wrote: > On 27.03.20 17:01, David Hildenbrand wrote: > > On 27.03.20 16:34, Christian Borntraeger wrote: > >> > >> > >> On 27.03.20 16:29, David Hildenbrand wrote: > >>> Historically, we fixed up the RAM size (rounded it down), to fit into > >>> storage increments. Since commit 3a12fc61af5c ("390x/s390-virtio-ccw: use > >>> memdev for RAM"), we no longer consider the fixed-up size when > >>> allcoating the RAM block - which will break migration. > >>> > >>> Let's simply drop that manual fixup code and let the user supply sane > >>> RAM sizes. This will bail out early when trying to migrate (and make > >>> an existing guest with e.g., 12345 MB non-migratable), but maybe we > >>> should have rejected such RAM sizes right from the beginning. > >>> > >>> As we no longer fixup maxram_size as well, make other users use ram_size > >>> instead. Keep using maxram_size when setting the maximum ram size in KVM, > >>> as that will come in handy in the future when supporting memory hotplug > >>> (in contrast, storage keys and storage attributes for hotplugged memory > >>> will have to be migrated per RAM block in the future). > >>> > >>> This fixes (or rather rejects early): > >>> > >>> 1. Migrating older QEMU to upstream QEMU (e.g., with "-m 1235M"), as the > >>> RAM block size changed. > >> > >> Not sure I like this variant. Instead of breaking migration (that was > >> accidentially done by Igors changes) we now reject migration from older > >> QEMUs to 5.0. This is not going to help those that still have such guests > >> running and want to migrate. > > > > As Igor mentioned on another channel, you most probably can migrate an > > older guest by starting it on the target with a fixed-up size. > > > > E.g., migrate an old QEMU "-m 1235M" to a new QEMU "-m 1234M" > > Yes, that should probably work. I'm in process of testing it. > > Not sure how many such weird-size VMs we actually do have in practice. > > I am worried about some automated deployments where tooling has created > these sizes for dozens or hundreds of containers in VMS and so. Yep, it's possible but then that tooling/configs should be fixed to work with new QEMU that validates user's input.