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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 5BE81C0650F for ; Tue, 30 Jul 2019 15:42:13 +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 35626229EB for ; Tue, 30 Jul 2019 15:42:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35626229EB 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]:34050 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsUGS-00053N-AR for qemu-devel@archiver.kernel.org; Tue, 30 Jul 2019 11:42:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46385) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsUG5-0004cP-Go for qemu-devel@nongnu.org; Tue, 30 Jul 2019 11:41:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsUG4-0001Kt-Hb for qemu-devel@nongnu.org; Tue, 30 Jul 2019 11:41:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60990) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsUG4-0001KE-Bo; Tue, 30 Jul 2019 11:41:48 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 2A35C330272; Tue, 30 Jul 2019 15:41:47 +0000 (UTC) Received: from work-vm (ovpn-117-45.ams2.redhat.com [10.36.117.45]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EFD175D6B2; Tue, 30 Jul 2019 15:41:45 +0000 (UTC) Date: Tue, 30 Jul 2019 16:41:43 +0100 From: "Dr. David Alan Gilbert" To: Igor Mammedov Message-ID: <20190730154143.GE2678@work-vm> References: <20190729145229.4333-1-imammedo@redhat.com> <20190729145229.4333-2-imammedo@redhat.com> <20190729175315.GK2756@work-vm> <20190730152558.2e1aa23a@Igors-MacBook-Pro> <41ee4043-0f91-9bfa-f3f6-f85358250bb9@redhat.com> <20190730163557.034b876d@Igors-MacBook-Pro> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190730163557.034b876d@Igors-MacBook-Pro> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 30 Jul 2019 15:41:47 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH RFC 1/2] memory: make MemoryRegion alias migratable 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: Paolo Bonzini , qemu-s390x@nongnu.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Igor Mammedov (imammedo@redhat.com) wrote: > On Tue, 30 Jul 2019 15:34:54 +0200 > Paolo Bonzini wrote: > > > On 30/07/19 15:25, Igor Mammedov wrote: > > > I'd guess you've meant RAMBlocks instead of memory regions, if that's it > > > then yes, every alias pointing to RAM backed memory region will have > > > RAMBlock that's points to aliased part of aliased memory region. > > > > The question is just, does it break migration from old QEMU to new QEMU > > on x86 (which has plenty of RAM-backed aliases)? If not, explain that > > in the commit message or in a code comment. > > pc/q35 old<->new new<->old ping pong tests worked fine (qemu with default devices). > > My understanding was that one needs to call vmstate_register_ram() > to make memory region migratable, which marks specific RAMBlock > as migratable. So just assigning new RAMBlock to mr->ram_block shouldn't > affect migration, unless vmstate_register_ram() is called on alias. You're right; that's actually relatively new and I forget about it. From Cedric's b895de50271 in 3.0, before that we migrated every RAMBlock. So yes, I think you should be OK. Dave > I'll add it to commit message. > > > > > Paolo > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK