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 30A19C83F26 for ; Tue, 29 Jul 2025 16:35:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ugnIO-0001bT-Ef; Tue, 29 Jul 2025 12:35:21 -0400 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 1ugmyZ-0000Kf-IL for qemu-devel@nongnu.org; Tue, 29 Jul 2025 12:15:03 -0400 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 1ugmyE-0000bZ-Jf for qemu-devel@nongnu.org; Tue, 29 Jul 2025 12:14:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1753805666; h=from:from:reply-to: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=yiGyH8B88F/ydwXBYIRpYlSr2t4V4le1i+Z6GB3eDs4=; b=CUz3flAu0Db5U4pJZYi3NOmNthdseWdxf/PtYySX5XGYm19rWI7RAbJARAKfNYUPaI651A 6lHIA+R3EnYJuXRpp/qyKnIVYsOFVwFJOoBO3T2kfzOj7TY3zAi/uPKukoYLjL5rSZ/ych sMbq0OsXJ+E6LvnO+gvyHj2C8kBMKwM= 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-241-igJnR-3WP26gelfMpfaJQA-1; Tue, 29 Jul 2025 12:09:15 -0400 X-MC-Unique: igJnR-3WP26gelfMpfaJQA-1 X-Mimecast-MFC-AGG-ID: igJnR-3WP26gelfMpfaJQA_1753805354 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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6197519560A3 for ; Tue, 29 Jul 2025 16:09:14 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.12]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 675BC180035E; Tue, 29 Jul 2025 16:09:12 +0000 (UTC) Date: Tue, 29 Jul 2025 17:09:09 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Cornelia Huck Cc: Andrea Bolognani , Paolo Bonzini , "Michael S. Tsirkin" , qemu-devel@nongnu.org Subject: Re: [PATCH 2/2] watchdog: generic name for i6300esb Message-ID: References: <20250610143259.1056400-3-cohuck@redhat.com> <877c09792e.fsf@redhat.com> <874iva7so9.fsf@redhat.com> <87tt2v3s16.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87tt2v3s16.fsf@redhat.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 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, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jul 29, 2025 at 06:01:25PM +0200, Cornelia Huck wrote: > On Thu, Jul 17 2025, Daniel P. Berrangé wrote: > > > On Thu, Jul 17, 2025 at 05:17:42PM +0200, Cornelia Huck wrote: > >> On Tue, Jul 15 2025, Daniel P. Berrangé wrote: > >> > >> > On Tue, Jul 15, 2025 at 09:16:24AM -0700, Andrea Bolognani wrote: > >> >> You can point them to documentation over and over again, or you can > >> >> work to prevent the confusion/annoyance from showing up in the first > >> >> place. Which of the two approaches is a better use of anyone's time > >> >> is up for debate. > >> >> > >> >> I for one am grateful that someone put the time in all those years > >> >> ago and, as a result, PCI and USB controllers don't suffer from the > >> >> problem today. Ultimately it's up to Connie though. > >> > > >> > The PCI/USB controller situation is not the same tradeoff though. > >> > Those guest kernel drivers will identify and attach to these two > >> > controllers regardless of their PCI vendor/product, via the PCI > >> > class property. In that case changing the PCI ID and other device > >> > metadata in QEMU is cheap as it has no negative impact on guest OS > >> > driver compibility. > >> > > >> > In the case of 6300ESB though the guest driver is tied directly to > >> > the currently used PCI device product/vendor ID. > >> > > >> > If we change this then we have actually created new functional > >> > problems with guest/QEMU compatibility, in order to placate a > >> > non-functional problem. That is not a good thing. > >> > >> I don't think the suggestion was to disable the existing driver on > >> non-Intel setups, but to add a more generic one. Still, more work to get > >> this actually propagated into guests than doing the change in > >> QEMU. Before I start down that route, I'd like to know whether the issue > >> is actually big enough to make investing time there worth it. > > > > If we're a mmgmt app provisioning a guest, we have to choose what > > watchdog to create - either the old one which works everywhere > > that currently has a driver, or the new one will will work in > > far fewer places. We'll have to wire up guest OS info about > > watchdogs into osinfo, and then wire up all the mgmt apps to > > query this and take action based off it. All possible, but it > > still feels like a huge waste of time to me. > > The fact that the device is something emulated and not the Intel > hardware device is actually visible to the guest: > > 00:02.0 System peripheral: Intel Corporation 6300ESB Watchdog Timer > Subsystem: Red Hat, Inc. QEMU Virtual Machine > Flags: fast devsel > Memory at 10804000 (32-bit, non-prefetchable) [size=16] > Kernel driver in use: i6300ESB timer > Kernel modules: i6300esb > > (lspci -v so unfortunately not immediately obvious, but still) > > AFAIK the BSDs do not have a driver for this device at the moment -- and > given what turns up when searching for i6300ESB, someone implementing a > driver is far more likely to pick the exising PCI ID. I see vague references (with unfortunately 404 links) to FreeBSD supporting some ICH watchdogs, which might mean it is compatible with the q35 built-in watchdog that all x86 q35 machines get by default. That wouldn't help non-x86 BSD though. > Windows would also need some dance according to Yan's mail, for unclear > benefits. Off-list, Richard Jones pointed to the ACPI Watchdog WADT specification from Microsoft which appears to the most viable solution for Windows guests - at least from x86 POV, but hopefully any future Wndows aarch64 too: https://download.microsoft.com/download/a/f/7/af7777e5-7dcd-4800-8a0a-b18336565f5b/HardwareWDTSpec.doc The ACPI watchdog sounds like potentially the best bet for a working solution across Linux and Windows, on any arch that does ACPI.... if we can just find someone to write a QEMU driver for it.... With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|