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 0DCEDC43458 for ; Mon, 13 Jul 2026 18:09:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wjL6A-0004j2-Ub; Mon, 13 Jul 2026 14:09:46 -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 1wjL63-0004ho-Hv for qemu-devel@nongnu.org; Mon, 13 Jul 2026 14:09:40 -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 1wjL61-00077c-F7 for qemu-devel@nongnu.org; Mon, 13 Jul 2026 14:09:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783966176; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XJzNZVBzm0p+zNKgNuGwiiBlfxocU2VnvfvufnLPBS0=; b=TDXDxetkGQ7+SZIlqGoM324mK99vu5BVx3K/s9QtEGZSvklgAeI2jJaICPrTdfzMdWf0yI /E/joc9031xr+7rEGn94cMq/83uE3TGe5Ro4H6U/0c4HkSE0bHwSWT97ZE1AT15v2ga2gL l7nVbDdQP7s1Vz7jaAEsI3iPsdShKzE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-310-cj0lTyjxOMORbXuxsHTSkw-1; Mon, 13 Jul 2026 14:09:32 -0400 X-MC-Unique: cj0lTyjxOMORbXuxsHTSkw-1 X-Mimecast-MFC-AGG-ID: cj0lTyjxOMORbXuxsHTSkw_1783966171 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B875F1801379; Mon, 13 Jul 2026 18:09:30 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.4]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B44BA3000B4B; Mon, 13 Jul 2026 18:09:29 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 658CA21E6920; Mon, 13 Jul 2026 20:09:27 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: Markus Armbruster , Peter Maydell , QEMU Developers , Paolo Bonzini , Pedro Barbuda , Mohamed Mediouni , Nicholas Piggin , Harsh Prateek Bora , Cornelia Huck , Eric Farman , Matthew Rosato Subject: Re: what is qemu_system_guest_panicked() for? In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Mon, 13 Jul 2026 16:02:29 +0100") References: <87cxwrtgfd.fsf@pond.sub.org> <87se5ngln1.fsf@pond.sub.org> <87bjcbf0vu.fsf@pond.sub.org> Date: Mon, 13 Jul 2026 20:09:27 +0200 Message-ID: <874ii2ep7s.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: permerror client-ip=170.10.133.124; envelope-from=armbru@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, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 autolearn=ham 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 Daniel P. Berrang=C3=A9 writes: > On Mon, Jul 13, 2026 at 03:57:25PM +0200, Markus Armbruster wrote: >> Daniel P. Berrang=C3=A9 writes: [...] >> > When libvirt see a GUEST_PANICKED, it will transition the state to >> > "CRASHED" and assign a reason of "PANICKED" as the trigger / cause. >> > >> > Then depending on the guest XML config for it will do one >> > of >> > >> > * Take a core dump of QEMU >> > * Terminate QEMU >> > * Restart QEMU >> > * Take a core dump of QEMU and restart >> > * Leave it in crashed state (to allow a debugger to attach) >> > >> > >> > The "machine check" and "unknown VM exit" scenarios, would still map >> > to libvirt's "CRASHED" state, but we would want to assign distinct >> > "cause" for each of them. >>=20 >> Say we add event GUEST_MACHINE_CHECK, then send it instead of >> GUEST_PANICKED on a machine check. >>=20 >> With an updated version of libvirt, this changes exactly the "cause" >> recorded for a machine check in the "CRASHED" state. This change is >> desirable. >>=20 >> Older versions of libvirt ignore the unknown GUEST_MACHINE_CHECK event. >> They therefore no longer take the action. This is >> undesirable, I'm afraid. Is it? >>=20 >> An orderly transition could look like this: >>=20 >> 1. Add a new event for each distinct cause, and emit the appropriate >> event in addition to GUEST_PANICKED. >>=20 >> 2. Deprecate GUEST_PANICKED. >>=20 >> 3. Remove GUEST_PANICKED after a suitable grace period. > > Another option is to accept "GUEST_PANICKED" as a sub-optimal name > forever and add a "source" field to the event to explain what actually > triggered it, where "source" can be "guest-os", "machine-check", ... > etc... Yes, that's a compatible extension. > Which would probably be better compatible with libvirt too > > With regards, > Daniel