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 lists1p.gnu.org (lists1p.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 A0607F9B601 for ; Wed, 22 Apr 2026 09:54:00 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wFUHE-00038b-T0; Wed, 22 Apr 2026 05:53:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wFUHD-00037Z-8H for qemu-devel@nongnu.org; Wed, 22 Apr 2026 05:53:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wFUHB-0005EH-UR for qemu-devel@nongnu.org; Wed, 22 Apr 2026 05:53:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776851625; 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: in-reply-to:in-reply-to:references:references; bh=mpLL2JsAvlLGdZ0LkOdNtXVSOtggLdChHixrjvr2xpI=; b=cYTyfCMTPRgyx5t8jz1a3bUP9aYZv70Hx4kb+uCqFtiFu3s8aZcuowo1fKAOAxj77YpyFK 9z5+0I1tcX2/DRCWxzxRK91XUaRpyHqXNPdlxfo6U5uZjP5du3ZPhfFeJo8T7HRRdMqXpj AeINDfPgBbjMzs1EjrstpHtgcXr0Jqc= Received: from mx-prod-mc-01.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-660-vHFdUsUXOoeiwSuhiVmAvQ-1; Wed, 22 Apr 2026 05:53:40 -0400 X-MC-Unique: vHFdUsUXOoeiwSuhiVmAvQ-1 X-Mimecast-MFC-AGG-ID: vHFdUsUXOoeiwSuhiVmAvQ_1776851618 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EA6231956095; Wed, 22 Apr 2026 09:53:37 +0000 (UTC) Received: from localhost (dhcp-192-224.str.redhat.com [10.33.192.224]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C6F7E3000C15; Wed, 22 Apr 2026 09:53:36 +0000 (UTC) From: Cornelia Huck To: Jaehoon Kim , qemu-devel@nongnu.org, qemu-s390x@nongnu.org Cc: richard.henderson@linaro.org, iii@linux.ibm.com, david@kernel.org, pasic@linux.ibm.com, borntraeger@linux.ibm.com, farman@linux.ibm.com, mjrosato@linux.ibm.com, Jaehoon Kim , Mohamed Mediouni Subject: Re: [PATCH v2 1/1] hw/s390x/ccw: Disable legacy virtio-pci by default (v11.1+) In-Reply-To: <20260420144759.2970726-2-jhkim@linux.ibm.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: <20260420144759.2970726-1-jhkim@linux.ibm.com> <20260420144759.2970726-2-jhkim@linux.ibm.com> User-Agent: Notmuch/0.39 (https://notmuchmail.org) Date: Wed, 22 Apr 2026 11:53:34 +0200 Message-ID: <87y0ifs4m9.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Apr 20 2026, Jaehoon Kim wrote: > On the s390 Linux kernel, IO_SPACE_LIMIT has been 0 since the initial > zPCI implementation (commit cd24834130ac "s390/pci: base support"), > making I/O BARs unusable. > > However, when virtio-pci devices operate in transitional mode, QEMU > unconditionally exposes the legacy interface via BAR0. This results in > firmware warnings during PCI enumeration, such as: > > pci 0005:00:00.0: [Firmware Bug]: BAR 0: invalid; can't size > > even though BAR0 is never usable on the s390 kernel. > > Close this gap by disabling legacy virtio-pci support starting from > machine version 11.1. This effectively makes virtio-pci devices > non-transitional and prevents the creation of the unusable legacy I/O > BAR. > > This introduces s390x-specific global compatibility properties that > set disable-legacy=on as the default for virtio-pci devices. Machine > versions v11.0 and earlier set disable-legacy=off to maintain their > original default behavior (legacy support enabled), ensuring VMs > created with those versions continue to work identically. > > Users can override the default on the command line if needed: > - On v11.1+: -global virtio-pci.disable-legacy=off (to enable legacy) > - On v11.0-: -global virtio-pci.disable-legacy=on (to disable legacy) > > Signed-off-by: Jaehoon Kim > Reviewed-by: Mohamed Mediouni > --- > hw/s390x/s390-virtio-ccw.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) Thanks, queued to s390-next.