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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 C9960C0650F for ; Tue, 30 Jul 2019 13:43:07 +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 9F658206B8 for ; Tue, 30 Jul 2019 13:43:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F658206B8 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]:33036 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsSPC-0008BM-Uo for qemu-devel@archiver.kernel.org; Tue, 30 Jul 2019 09:43:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51543) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsSOd-0007Ek-Es for qemu-devel@nongnu.org; Tue, 30 Jul 2019 09:42:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsSOc-0007sq-HQ for qemu-devel@nongnu.org; Tue, 30 Jul 2019 09:42:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36016) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsSOc-0007s6-An for qemu-devel@nongnu.org; Tue, 30 Jul 2019 09:42:30 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B441D3091D63 for ; Tue, 30 Jul 2019 13:42:28 +0000 (UTC) Received: from redhat.com (ovpn-116-30.ams2.redhat.com [10.36.116.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B3A965C1B4; Tue, 30 Jul 2019 13:42:25 +0000 (UTC) From: Juan Quintela To: "Dr. David Alan Gilbert \(git\)" In-Reply-To: <20190730093719.12958-3-dgilbert@redhat.com> (David Alan Gilbert's message of "Tue, 30 Jul 2019 10:37:19 +0100") References: <20190730093719.12958-1-dgilbert@redhat.com> <20190730093719.12958-3-dgilbert@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) Date: Tue, 30 Jul 2019 15:42:23 +0200 Message-ID: <87mugvk5a8.fsf@trasno.org> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Tue, 30 Jul 2019 13:42:28 +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 2/2] pcie_root_port: Disable ACS on older machines 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: , Reply-To: quintela@redhat.com Cc: qemu-devel@nongnu.org, ehabkost@redhat.com, mst@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" "Dr. David Alan Gilbert (git)" wrote: > From: "Dr. David Alan Gilbert" > > ACS got added in 4.0 unconditionally, that broke older<->4.0 migration > where there was a PCIe root port. > Fix this by turning it off for 3.1 and older machines; note this > fixes compatibility for older QEMUs but breaks compatibility with 4.0 > for older machine types. > > machine type source qemu dest qemu > 3.1 3.1 4.0 broken > 3.1 3.1 4.1rc2 broken > 3.1 3.1 4.1+this OK ++ > 3.1 4.0 4.1rc2 OK > 3.1 4.0 4.1+this broken -- > 4.0 4.0 4.1rc2 OK > 4.0 4.0 4.1+this OK > > So we gain and lose; the consensus seems to be treat this as a > fix for older machine types. > > Signed-off-by: Dr. David Alan Gilbert > --- Reviewed-by: Juan Quintela