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 EE1BBC43458 for ; Mon, 13 Jul 2026 10:30:40 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wjDvX-0006wE-UW; Mon, 13 Jul 2026 06:30:19 -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 1wjDvV-0006w6-1A for qemu-devel@nongnu.org; Mon, 13 Jul 2026 06:30:17 -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 1wjDvR-0000tQ-9D for qemu-devel@nongnu.org; Mon, 13 Jul 2026 06:30:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783938611; 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=KokfjhKtSvSEYLUMI2jEvq11anwkHCvAtQ2JaeaaWiE=; b=VaMduf0+VmCBLMuYtezkoKbchBBdSmpLw7UA2OnbucJiwockQIiYmRYTeZlGyMYYv+eldn lIsq0H7Co8/rxGQrQNyyGwttVKxfVSfVhjmVDTatod5E7HkFIUfK2XNSw5BFht+IPHMsRN wvUqwiG7M0Hyn2HCDeJQplql/+i+EGU= Received: from mx-prod-mc-06.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-5-cPXAvD0OMx6aUuQhFUiDWw-1; Mon, 13 Jul 2026 06:30:08 -0400 X-MC-Unique: cPXAvD0OMx6aUuQhFUiDWw-1 X-Mimecast-MFC-AGG-ID: cPXAvD0OMx6aUuQhFUiDWw_1783938606 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 346331800A7B; Mon, 13 Jul 2026 10:30:06 +0000 (UTC) Received: from localhost (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 89F9A19560AB; Mon, 13 Jul 2026 10:30:05 +0000 (UTC) From: Cornelia Huck To: =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Markus Armbruster Cc: Peter Maydell , QEMU Developers , Paolo Bonzini , Pedro Barbuda , Mohamed Mediouni , Nicholas Piggin , Harsh Prateek Bora , Eric Farman , Matthew Rosato Subject: Re: what is qemu_system_guest_panicked() for? In-Reply-To: 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: <87cxwrtgfd.fsf@pond.sub.org> User-Agent: Notmuch/0.40 (https://notmuchmail.org) Date: Mon, 13 Jul 2026 12:30:03 +0200 Message-ID: <87fr1ni3mc.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: permerror client-ip=170.10.129.124; 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, 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 On Mon, Jul 13 2026, Daniel P. Berrang=C3=A9 wrote: > On Mon, Jul 13, 2026 at 10:57:58AM +0200, Markus Armbruster wrote: >> Daniel P. Berrang=C3=A9 writes: >>=20 >> > On Fri, Jul 10, 2026 at 05:02:53PM +0100, Peter Maydell wrote: >>=20 >> [...] >>=20 >> >> So I guess my question is, is it OK to mash these two categories of >> >> "we can't keep running the VM" together, or should we define a new >> >> one for the "unrecoverable guest error" case, or do we already have >> >> some better thing to do that I missed? >> > >> > IMHO we should NOT be abusing "panicked" for cases which are >> > not guest OS panics. >>=20 >> Point. >>=20 >> > Adding new QMP events is cheap and we should do so. >>=20 >> Changing the event sent on a certain situation is technically a >> compatibility break. Would it matter here? > > What wins "compat break" or "bug fix" ? A strict POV prevents almost > any bug fixes, if you want to remain bug-for-bug compatible with > old QEMU. > > With my "management app" hat on, I want QEMU to stop sending panic > events for things that are not panics, as that is triggering incorrect > actions / admin activities. ie on a panic, I'm going to take a guest > memory dump and try to analyse what is broken in the guest kernel. That would argue for e.g. a guest exception loop being a "panic" as well, as the admin may want to debug that. > > The QAPI spec says: > > ## > # @GUEST_PANICKED: > # > # Emitted when guest OS panic is detected > > > and > > ## > # @RunState: > # > # An enumeration of VM run states. > # > .. > # @guest-panicked: guest has been panicked as a result of guest OS > # panic > > > I don't think "machine check exception" or "unknown VM exit" > can be said to match either of those docs, and thus fixing > compliance should trump bug-for-bug compatibility IMHO. I'm wondering whether we first need to agree upon a common definition of what a "guest OS panic" is. "The Linux kernel ran into a panic() statement" clearly is; is "the guest OS put itself into a state of which the only way out is a reboot" a "guest OS panic" as well, or only in some cases?