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=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 156D5C433DF for ; Mon, 29 Jun 2020 17:06:33 +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 D4215255A5 for ; Mon, 29 Jun 2020 17:06:32 +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="UkgnrSTG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4215255A5 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]:53884 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jpxEl-0002UX-Qp for qemu-devel@archiver.kernel.org; Mon, 29 Jun 2020 13:06:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34402) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jpxDs-0001jA-Rs for qemu-devel@nongnu.org; Mon, 29 Jun 2020 13:05:36 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:33206 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 1jpxDq-0003IB-8D for qemu-devel@nongnu.org; Mon, 29 Jun 2020 13:05:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593450332; 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: in-reply-to:in-reply-to:references:references; bh=8UDDMCnqTV30z6QPivwS8VQyKr17DzN4HDVxw//U6UM=; b=UkgnrSTGrs+5XgXN0MhDQWJX95z9pnfsmMFzDN5LkhGSaY15ng3U0SahKWiiycOxk1ZIXs Rf2ZFM5ZWnxw/lDRxLyEskVKR2BmJ/df4I3dNPoryFV9b7c5Homk9qYgmqdXvJmSj/qC5i 5PnLY8Nqbu79ckTe8rrrY8uc20eZ88o= 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-499-_aBoKONuNoy4E7FzIl_CbQ-1; Mon, 29 Jun 2020 13:05:29 -0400 X-MC-Unique: _aBoKONuNoy4E7FzIl_CbQ-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 A53B618B6388 for ; Mon, 29 Jun 2020 17:05:28 +0000 (UTC) Received: from work-vm (ovpn-114-210.ams2.redhat.com [10.36.114.210]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CFA0E5D9DA; Mon, 29 Jun 2020 17:05:22 +0000 (UTC) Date: Mon, 29 Jun 2020 18:05:19 +0100 From: "Dr. David Alan Gilbert" To: "Michael S. Tsirkin" Subject: Re: [PATCH RFC] virtio-fs: force virtio 1.x usage Message-ID: <20200629170519.GM2908@work-vm> References: <20200629102758.421552-1-cohuck@redhat.com> <20200629104948-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: <20200629104948-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.14.3 (2020-06-14) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.81; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/29 01:03:51 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: Cornelia Huck , qemu-devel@nongnu.org, Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Michael S. Tsirkin (mst@redhat.com) wrote: > On Mon, Jun 29, 2020 at 12:27:58PM +0200, Cornelia Huck wrote: > > virtio-fs devices are only specified for virtio-1, so it is unclear > > how a legacy or transitional device should behave. > > > > Signed-off-by: Cornelia Huck > > --- > > > > Forcing off legacy now (after the virtio-fs device has already been > > available) may have unintended consequences, therefore RFC. > > > > By default, a virtio-pci device uses 'AUTO' for disable_legacy, which > > will resolve to different values based upon which bus the device has > > been plugged. Therefore, forcing disable_legacy may result in the same > > device or a quite different one. > > > > Even though pre-virtio-1 behaviour of virtio-fs devices is simply not > > specified, toggling disable_legacy will have implications for the BAR > > layout, IIRC, and therefore a guest might end up getting a different > > device, even if it always used it with virtio-1 anyway. > > > > Not sure what the best way to solve this problem is. Adding a compat > > property for disable_legacy=AUTO may be the right thing to do, but I'm > > not quite clear if there are any further implications here. > > Well I notice that this device is not migrateable. > So I think that we can just switch it over and be done with it. Yes, I think I'm OK with that - although you could add the compat flag in the machine type I guess. Dave > > > Whatever we do here, we should make sure that the ccw incarnation of > > this device indeed forces virtio-1. > > I agree. I notice that the API virtio_pci_force_virtio_1 turned out > to be too fragile. I propose that instead we have a whitelist of > devices which can be legacy or transitional. Force rest to modern. > > > > --- > > hw/virtio/vhost-user-fs-pci.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/hw/virtio/vhost-user-fs-pci.c b/hw/virtio/vhost-user-fs-pci.c > > index e11c889d82b3..244205edf765 100644 > > --- a/hw/virtio/vhost-user-fs-pci.c > > +++ b/hw/virtio/vhost-user-fs-pci.c > > @@ -44,6 +44,7 @@ static void vhost_user_fs_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) > > vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 2; > > } > > > > + virtio_pci_force_virtio_1(vpci_dev); > > qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > > } > > > > -- > > 2.25.4 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK