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 X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FE1EC433DB for ; Fri, 19 Feb 2021 12:36:40 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D2CF660202 for ; Fri, 19 Feb 2021 12:36:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2CF660202 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49372 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lD51S-0000EY-JX for qemu-devel@archiver.kernel.org; Fri, 19 Feb 2021 07:36:38 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54544) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lD4ci-0006Se-CV for qemu-devel@nongnu.org; Fri, 19 Feb 2021 07:11:05 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22656) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lD4ce-0004aR-JI for qemu-devel@nongnu.org; Fri, 19 Feb 2021 07:11:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613736659; 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=45Dm/mZfrJbWzizoN9wLVx4pShqBQ+9iMXBHgbG5TR0=; b=VIcFCYwwxZkaEh9FI7T3JH5HW0ogcVtMvS+Wvssi+66HaS5X2mizXEwZV/tQUMLi+YSNql fO24TCnW+MG1GPHHSW/G7cPjtW0awyoyfgsENRgbU08yQBXihWkUBOQp0Ck9kesZsXcUaI yNBJQ8Jb+oFqz3zQPWLTIfyBBafK4gI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-175-AFE5aQfpPteMhmzp8Pa9qA-1; Fri, 19 Feb 2021 07:10:43 -0500 X-MC-Unique: AFE5aQfpPteMhmzp8Pa9qA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BDEB1100A8E9; Fri, 19 Feb 2021 12:10:40 +0000 (UTC) Received: from redhat.com (ovpn-113-184.ams2.redhat.com [10.36.113.184]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 653155C1BB; Fri, 19 Feb 2021 12:10:30 +0000 (UTC) Date: Fri, 19 Feb 2021 12:10:27 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Maydell Subject: Re: [PATCH 2/7] hw/boards: Introduce 'kvm_supported' field to MachineClass Message-ID: References: <20210219114428.1936109-1-philmd@redhat.com> <20210219114428.1936109-3-philmd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.0.5 (2021-01-21) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Cornelia Huck , kvm-devel , David Hildenbrand , Mark Cave-Ayland , Aleksandar Rikalo , "Edgar E. Iglesias" , Huacai Chen , Halil Pasic , Christian Borntraeger , =?utf-8?B?SGVydsOp?= Poussineau , Leif Lindholm , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Thomas Huth , Eduardo Habkost , Alistair Francis , Richard Henderson , Greg Kurz , QEMU Developers , qemu-s390x , qemu-arm , David Gibson , Radoslaw Biernacki , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , qemu-ppc , Paolo Bonzini , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Feb 19, 2021 at 12:08:05PM +0000, Peter Maydell wrote: > On Fri, 19 Feb 2021 at 11:58, Daniel P. Berrangé wrote: > > Is the behaviour reported really related to KVM specifically, as opposed > > to all hardware based virt backends ? > > > > eg is it actually a case of some machine types being "tcg_only" ? > > Interesting question. At least for Arm the major items are: > * does the accelerator support emulation of EL3/TrustZone? > (KVM doesn't; this is the proximate cause of the assertion > failure if you try to enable KVM for the raspi boards.) > * does the board type require a particular CPU type which > KVM doesn't/can't support? > Non-KVM accelerators could at least in theory have different answers > to those questions, though in practice I think they do not. > > I think my take is that we probably should mark the boards > as 'tcg-only' vs 'not-tcg-only', because in practice that's > the interesting distinction. Specifically, our security policy > https://qemu.readthedocs.io/en/latest/system/security.html > draws a boundary between "virtualization use case" and > "emulated", so it's really helpful to be able to say clearly > "this board model does not support virtualization, and therefore > any bugs in it or its devices are simply outside the realm of > being security issues" when doing analysis of the codebase or > when writing or reviewing new code. Oh, yes, that is useful to correlate with. > If we ever have support for some new accelerator type where there's > a board type distinction between KVM and that new accelerator and > it makes sense to try to say "this board is supported by the new > thing even though it won't work with KVM", the folks interested in > adding that new accelerator will have the motivation to look > into exactly which boards they want to enable support for and > can add a funky_accelerator_supported flag or whatever at that time. > > Summary: we should name this machine class field > "virtualization_supported" and check it in all the virtualization > accelerators (kvm, hvf, whpx, xen). Agreed. 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 :|