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 1085CD0EE00 for ; Tue, 25 Nov 2025 17:21:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vNwix-00079U-O9; Tue, 25 Nov 2025 12:21:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vNwiR-00074h-Vw for qemu-arm@nongnu.org; Tue, 25 Nov 2025 12:20:37 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vNwiQ-0007mh-1i for qemu-arm@nongnu.org; Tue, 25 Nov 2025 12:20:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764091233; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XgxRnAe/XfSsk73XZyiGe0FyizdWdlwh81PBGRnwXic=; b=WibqpfV7AMAwTcUQtfYMdDjXy8crJxU7KIp6rZ/WrnOuYfatq2RFlqPnHYWBezdufjzbv1 SLo1GaRN+dqXYpDa7pNyFFEZShIE8HRWlGgcxVNCheKW4G9azMhmb89dR7D6QB0QK3CK9Y gp6go0gKkDBjVy1BhC6Ky/HFAYYym64= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-563-JXPjFXKkO0aQFcWWAMpd6A-1; Tue, 25 Nov 2025 12:20:29 -0500 X-MC-Unique: JXPjFXKkO0aQFcWWAMpd6A-1 X-Mimecast-MFC-AGG-ID: JXPjFXKkO0aQFcWWAMpd6A_1764091226 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0C3F71956048; Tue, 25 Nov 2025 17:20:26 +0000 (UTC) Received: from localhost (dhcp-192-239.str.redhat.com [10.33.192.239]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A54811800451; Tue, 25 Nov 2025 17:20:24 +0000 (UTC) From: Cornelia Huck To: Eric Auger , eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, peter.maydell@linaro.org, maz@kernel.org, oliver.upton@linux.dev, sebott@redhat.com, gshan@redhat.com, ddutile@redhat.com, peterx@redhat.com, philmd@linaro.org, pbonzini@redhat.com Subject: Re: [PATCH v3 09/11] hw/arm/virt: Declare AArch32 DBGDTRTX as safe to ignore in incoming stream In-Reply-To: <20251125100859.506228-10-eric.auger@redhat.com> Organization: "Red Hat GmbH, Sitz: Werner-von-Siemens-Ring 12, D-85630 Grasbrunn, Handelsregister: Amtsgericht =?utf-8?Q?M=C3=BCnchen=2C?= HRB 153243, =?utf-8?Q?Gesch=C3=A4ftsf=C3=BChrer=3A?= Ryan Barnhart, Charles Cachera, Avril Crosse O'Flaherty" References: <20251125100859.506228-1-eric.auger@redhat.com> <20251125100859.506228-10-eric.auger@redhat.com> User-Agent: Notmuch/0.38.3 (https://notmuchmail.org) Date: Tue, 25 Nov 2025 18:20:22 +0100 Message-ID: <878qfuowq1.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.152, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@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-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org Sender: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org On Tue, Nov 25 2025, Eric Auger wrote: > With the new infrastructure in place it is now feasible to teach > qemu that it is safe to ignore a sysreg in the incoming migration > stream. So with the plan to revert commit 4f2b82f60431 ("target/arm: > Reinstate bogus AArch32 DBGDTRTX register for migration compat) from > qemu 11 onwards, let's add a compat in 10.2 machine options stating > that this reg is safe to ignore. from 11.0 onwards we will not need > that register anymore. > > Signed-off-by: Eric Auger > > --- > > Theoretically removing that register could also impact other ARM > machines but I don't think we have any compat outside of arm virt, > do we? I don't think we give any guarantees outside of versioned machines (of which virt is the only one for ARM.) > --- > hw/arm/virt.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index ec0af8e6e7..c6a5146c92 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -100,6 +100,14 @@ static GlobalProperty arm_virt_compat_defaults[] = { > static const size_t arm_virt_compat_defaults_len = > G_N_ELEMENTS(arm_virt_compat_defaults); > > +#define DBGDTRTX 0x40200000200e0298 This probably wants a comment such as "bogus register erronously exposed on 10.2 and earlier" or so. > + > +static GlobalProperty arm_virt_compat_10_2[] = { > + { TYPE_ARM_CPU, "x-mig-safe-missing-regs", stringify(DBGDTRTX)}, > +}; > +static const size_t arm_virt_compat_10_2_len = > + G_N_ELEMENTS(arm_virt_compat_10_2); > + > /* > * This cannot be called from the virt_machine_class_init() because > * TYPE_VIRT_MACHINE is abstract and mc->compat_props g_ptr_array_new() > @@ -3536,6 +3544,7 @@ type_init(machvirt_machine_init); > > static void virt_machine_10_2_options(MachineClass *mc) > { > + compat_props_add(mc->compat_props, arm_virt_compat_10_2, arm_virt_compat_10_2_len); > } > DEFINE_VIRT_MACHINE_AS_LATEST(10, 2) > > -- > 2.52.0