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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 6F476C433DF for ; Wed, 1 Jul 2020 14:10:17 +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 3D147207BB for ; Wed, 1 Jul 2020 14:10:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Znzhp+c8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3D147207BB 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]:52308 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqdRI-0008GG-DK for qemu-devel@archiver.kernel.org; Wed, 01 Jul 2020 10:10:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59308) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqdG0-0004rG-Rw for qemu-devel@nongnu.org; Wed, 01 Jul 2020 09:58:36 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:23312 helo=us-smtp-delivery-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 1jqdFz-0005zZ-4h for qemu-devel@nongnu.org; Wed, 01 Jul 2020 09:58:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593611914; 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=QrIOMOmIcQInM0zOXDMWR1ys83jNQzl68Lwey36atNs=; b=Znzhp+c87M/sLrDXWQNgXLceHb1iGVYGGQYMi0RHsZyLRRpe87Ev05laFJxBVKLVXtSA3F 3za++6rXlr9RTt2ge9gAJovYxv2Ak7EvPys+kscc+lg0wl0qBzVl3fEqy36ysVwotQcMJr V30IokLVhePDLKkb0kjifJrwm+HnzVg= 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-240-AbH0u8VePca7krFRcpZcjA-1; Wed, 01 Jul 2020 09:58:32 -0400 X-MC-Unique: AbH0u8VePca7krFRcpZcjA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 97BAC80183C for ; Wed, 1 Jul 2020 13:58:31 +0000 (UTC) Received: from gondolin (ovpn-113-61.ams2.redhat.com [10.36.113.61]) by smtp.corp.redhat.com (Postfix) with ESMTP id D2B824F6A4; Wed, 1 Jul 2020 13:58:21 +0000 (UTC) Date: Wed, 1 Jul 2020 15:58:19 +0200 From: Cornelia Huck To: "Michael S. Tsirkin" Subject: Re: [PATCH RFC] virtio-fs: force virtio 1.x usage Message-ID: <20200701155819.55c64224.cohuck@redhat.com> In-Reply-To: <20200630074918-mutt-send-email-mst@kernel.org> References: <20200629102758.421552-1-cohuck@redhat.com> <20200629104948-mutt-send-email-mst@kernel.org> <20200629173933.35cea40f.cohuck@redhat.com> <20200629114515-mutt-send-email-mst@kernel.org> <20200630113527.7b27f34f.cohuck@redhat.com> <20200630064227-mutt-send-email-mst@kernel.org> <20200630133043.2be1d209.cohuck@redhat.com> <20200630074918-mutt-send-email-mst@kernel.org> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/01 01:05:53 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: Eric Auger , "Dr. David Alan Gilbert" , Stefan Hajnoczi , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 30 Jun 2020 09:02:31 -0400 "Michael S. Tsirkin" wrote: > On Tue, Jun 30, 2020 at 01:30:43PM +0200, Cornelia Huck wrote: > > On Tue, 30 Jun 2020 06:45:42 -0400 > > "Michael S. Tsirkin" wrote: > > > > > On Tue, Jun 30, 2020 at 11:35:27AM +0200, Cornelia Huck wrote: > > > > First, I noticed that virtio-iommu does not force virtio-1, either; I > > > > think it should? Eric? > > > > > > > > Then, there's the mechanism using different names for transitional and > > > > non-transitional devices. Devices that support both usually define both > > > > names (with disable_legacy and disable_modern set appropriately) and a > > > > base name (where the properties can be set manually for the desired > > > > effect). Most virtio-1 only devices set neither the non-transitional > > > > nor the transitional name and rely on virtio_pci_force_virtio_1() to > > > > disable legacy support. But there are outliers: > > > > > > > > * this device: it has only a non-transitional name > > > > ("vhost-user-fs-pci"), which means we automatically get the correct > > > > configuration; in order to define a transitional/legacy device, you > > > > would need to use the base name "vhost-user-fs-pci-base" explicitly, > > > > and it's unlikely that someone has been doing that. > > > > * virtio-iommu (which I *think* is a virtio-1 only device): it defines > > > > the full set of transitional, non-transitional, and base names. > > > > > > > > How should we proceed? > > > > * With this patch here, we can fence off the very unlikely possibility > > > > of somebody configuring a non-modern virtio-fs device for pci. We > > > > probably should do it, but I don't think we need compat handling. > > > > * For virtio-iommu, we should get an agreement what the desired state > > > > is. If it really should be modern only, we need compat handling, as > > > > the device had been added in 5.0. (And we need to figure out how to > > > > apply that compat handling.) > > > > > > > > > Well I know it's not really used on x86 yet, so no problem there. > > > > > > Which machines are actually affected? > > > > I'd suspect ARM, but breaking even a subset is not nice. > > OK so MMIO does not have transitional at all right? IIRC, yes. But I think there are ARM machines that use virtio-pci as well, right?