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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 D731EC433E0 for ; Thu, 23 Jul 2020 06:34:13 +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 9F3F5206E3 for ; Thu, 23 Jul 2020 06:34:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EWNdVTjf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F3F5206E3 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]:33130 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jyUo0-0000TL-UW for qemu-devel@archiver.kernel.org; Thu, 23 Jul 2020 02:34:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51306) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jyUnN-0008QH-7C for qemu-devel@nongnu.org; Thu, 23 Jul 2020 02:33:33 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:28063 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jyUnK-00008Y-IW for qemu-devel@nongnu.org; Thu, 23 Jul 2020 02:33:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595486009; 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=gP0ziDWKaozYPxJlEaJijEiUf6ovghsYvBsep3uCLjY=; b=EWNdVTjf0wHXfP76BZpRYuXSYp4nhIhgf7r3Za/G2FAsR1FgtLAjvoihhtOnIibTzqRMSV boSASO/zRXGrYr1Y5tsPuGAHI/KxLdij7fL5bLSUOdTbHjj95FkPz+eFcQv9F7WHnpX1xB 0mmVa/DLdWSvu5wwvTocpoc60LHjizU= 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-10--uCv4kzpNmKHO0pSzbikGQ-1; Thu, 23 Jul 2020 02:33:27 -0400 X-MC-Unique: -uCv4kzpNmKHO0pSzbikGQ-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 6E4AD58; Thu, 23 Jul 2020 06:33:26 +0000 (UTC) Received: from gondolin (ovpn-112-228.ams2.redhat.com [10.36.112.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 60EF45C1BB; Thu, 23 Jul 2020 06:33:16 +0000 (UTC) Date: Thu, 23 Jul 2020 08:33:13 +0200 From: Cornelia Huck To: David Hildenbrand Subject: Re: [PATCH 0/2] virtio: non-legacy device handling Message-ID: <20200723083313.49e3502a.cohuck@redhat.com> In-Reply-To: <4309b9dd-cc94-e183-60f8-67e4ec36c666@redhat.com> References: <20200707105446.677966-1-cohuck@redhat.com> <51e457ef-106e-1c1a-778d-4d53d9e48d8e@redhat.com> <20200720050215-mutt-send-email-mst@kernel.org> <4309b9dd-cc94-e183-60f8-67e4ec36c666@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=cohuck@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=cohuck@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/23 02:33:29 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: , Cc: Halil Pasic , Eric Auger , qemu-s390x@nongnu.org, qemu-devel@nongnu.org, "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 20 Jul 2020 11:07:51 +0200 David Hildenbrand wrote: > On 20.07.20 11:03, Michael S. Tsirkin wrote: > > On Mon, Jul 20, 2020 at 10:09:57AM +0200, David Hildenbrand wrote: > >> On 07.07.20 12:54, Cornelia Huck wrote: > >>> As discussed in "virtio-fs: force virtio 1.x usage", it seems like > >>> a good idea to make sure that any new virtio device (which does not > >>> support legacy virtio) is indeed a non-transitional device, just to > >>> catch accidental misconfigurations. We can easily compile a list > >>> of virtio devices with legacy support and have transports verify > >>> in their plugged callbacks that legacy support is off for any device > >>> not in that list. > >>> > >>> Most new virtio devices force non-transitional already, so nothing > >>> changes for them. vhost-user-fs-pci even does not allow to configure > >>> a non-transitional device, so it is fine as well. > >>> > >>> One problematic device, however, is virtio-iommu-pci. It currently > >>> offers both the transitional and the non-transitional variety of the > >>> device, and does not force anything. I'm unsure whether we should > >>> consider transitional virtio-iommu unsupported, or if we should add > >>> some compat handling. (The support for legacy or not generally may > >>> change based upon the bus, IIUC, so I'm unsure how to come up with > >>> something generic.) > >>> > >>> Cornelia Huck (2): > >>> virtio: list legacy-capable devices > >>> virtio: verify that legacy support is not accidentally on > >> > >> I'd squash both patches. Looking at patch #1, I wonder why we don't > >> store that information along with the device implementation? What was > >> the motivation to define this information separately? > > > > Because people seem to cut and paste code, so when one > > enables it in an old device, it gets pasted into a new one. > > With a list in a central place, it's easier to figure out > > what's going on. > > Makes sense, I suggest adding that to the patch description. "The list of devices supporting legacy is supposed to be static. We keep it in a central place to make sure that new devices do not enable legacy by accident." ? > > Both patches look sane to me (- squashing them). > Patch 1 does not change behaviour, while patch 2 does (for virtio-iommu-pci). Still would like an opinion whether changing the behaviour for virtio-iommu-pci with no compat handling is ok. (I could be persuaded to squash them.)