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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45F47C433F5 for ; Mon, 4 Oct 2021 14:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2588E61354 for ; Mon, 4 Oct 2021 14:27:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233851AbhJDO3V (ORCPT ); Mon, 4 Oct 2021 10:29:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:54902 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233767AbhJDO3U (ORCPT ); Mon, 4 Oct 2021 10:29:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633357651; 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=LIG9qMDkxH/Rmc/0k4eqilgYZwh4mc9sxcj/N2tODz8=; b=QLWl+Ob5uMsM/e5s1amWVa1Md+YVYYUwKqtyrWFrisKTjFFiGbj941ZklLEr/8i5MEJh+7 B22OowabuD21e7CAA5lG2vqge6Eogq4de4xUGZbi+LTBvm6KvOLHUUJ7NL2Owf+kM0CN4d 1hvWVEUFuMyi6cnUtWFi+P7D0HB3adc= 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-199-7_cAvUANPKCmXPubGlravA-1; Mon, 04 Oct 2021 10:27:27 -0400 X-MC-Unique: 7_cAvUANPKCmXPubGlravA-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 296B484A602; Mon, 4 Oct 2021 14:27:26 +0000 (UTC) Received: from localhost (unknown [10.39.193.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7C8C45C1CF; Mon, 4 Oct 2021 14:27:25 +0000 (UTC) From: Cornelia Huck To: "Michael S. Tsirkin" Cc: Halil Pasic , Jason Wang , Xie Yongji , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, markver@us.ibm.com, Christian Borntraeger , linux-s390@vger.kernel.org, virtio-dev@lists.oasis-open.org Subject: Re: [RFC PATCH 1/1] virtio: write back features before verify In-Reply-To: <20211004083455-mutt-send-email-mst@kernel.org> Organization: Red Hat GmbH References: <20210930012049.3780865-1-pasic@linux.ibm.com> <20210930070444-mutt-send-email-mst@kernel.org> <87fstm47no.fsf@redhat.com> <20211002141351-mutt-send-email-mst@kernel.org> <20211003070030.658fc94e.pasic@linux.ibm.com> <20211003021027-mutt-send-email-mst@kernel.org> <20211003032253-mutt-send-email-mst@kernel.org> <87ee912e45.fsf@redhat.com> <20211004083455-mutt-send-email-mst@kernel.org> User-Agent: Notmuch/0.32.1 (https://notmuchmail.org) Date: Mon, 04 Oct 2021 16:27:23 +0200 Message-ID: <878rz83lx0.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 04 2021, "Michael S. Tsirkin" wrote: > On Mon, Oct 04, 2021 at 02:01:14PM +0200, Cornelia Huck wrote: >> On Sun, Oct 03 2021, "Michael S. Tsirkin" wrote: >> > @@ -160,6 +163,33 @@ \subsection{Legacy Interface: A Note on Feature >> > Specification text within these sections generally does not apply >> > to non-transitional devices. >> > >> > +\begin{note} >> > +The device offers different features when used through >> > +the legacy interface and when operated in accordance with this >> > +specification. >> > +\end{note} >> > + >> > +Transitional drivers MUST use Devices only through the legacy interface >> >> s/Devices only through the legacy interface/devices through the legacy >> interface only/ >> >> ? > > Both versions are actually confused, since how do you > find out that device does not offer VIRTIO_F_VERSION_1? > > I think what this should really say is > > Transitional drivers MUST NOT accept VIRTIO_F_VERSION_1 through > the legacy interface. Ok, that makes sense. Would it make sense that transitional drivers MUST accept VERSION_1 through the non-legacy interface? Or is that redundant? > > > Does linux actually satisfy this? Will it accept VIRTIO_F_VERSION_1 > through the legacy interface if offered? I think that the Linux drivers will not operate on feature bit 32+ if they are in legacy mode? >> >> Generally, looks good to me. > > Do we want to also add explanation that features can be > changed until FEATURES_OK? I always considered that to be implict, as feature negotiation is not over until we have FEATURES_OK. Not sure whether we need an extra note.