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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0476AC433F5 for ; Tue, 7 Dec 2021 11:16:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235458AbhLGLUI (ORCPT ); Tue, 7 Dec 2021 06:20:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32790 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235631AbhLGLUI (ORCPT ); Tue, 7 Dec 2021 06:20:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638875797; 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=E5VGewCEz4fmcYf4Xe+YasUAuTzVOfztXoWjA/QsgxY=; b=KHjkJ7bSuEQBvNBcjL67DYZHEPRXnhpUVO+YtxUFHD1g/OGZ/X1sKECKkwpjm3MqMz5p+F H2ZEy0j1ITYvFhT66/52MZaRJgJkrHHSfj0Ko5wmGZdTCqqIKBOpLz6xiQJRzSX+A7y0ab F41mh6m0PeGjiuGPx+nEgZHP7XjXIOg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-260-2qrI2RQoP4ykCg57d5Zf0w-1; Tue, 07 Dec 2021 06:16:36 -0500 X-MC-Unique: 2qrI2RQoP4ykCg57d5Zf0w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E6FAB8042E1; Tue, 7 Dec 2021 11:16:34 +0000 (UTC) Received: from localhost (unknown [10.39.193.160]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 438B219C59; Tue, 7 Dec 2021 11:16:34 +0000 (UTC) From: Cornelia Huck To: Jason Gunthorpe Cc: Alex Williamson , Jonathan Corbet , linux-doc@vger.kernel.org, kvm@vger.kernel.org, Kirti Wankhede , Max Gurtovoy , Shameer Kolothum , Yishai Hadas Subject: Re: [PATCH RFC v2] vfio: Documentation for the migration region In-Reply-To: <20211206191933.GM4670@nvidia.com> Organization: Red Hat GmbH References: <20211130102611.71394253.alex.williamson@redhat.com> <20211130185910.GD4670@nvidia.com> <20211130153541.131c9729.alex.williamson@redhat.com> <20211201031407.GG4670@nvidia.com> <20211201130314.69ed679c@omen> <20211201232502.GO4670@nvidia.com> <20211203110619.1835e584.alex.williamson@redhat.com> <87zgpdu3ez.fsf@redhat.com> <20211206173422.GK4670@nvidia.com> <87tufltxp0.fsf@redhat.com> <20211206191933.GM4670@nvidia.com> User-Agent: Notmuch/0.34 (https://notmuchmail.org) Date: Tue, 07 Dec 2021 12:16:32 +0100 Message-ID: <87o85su0kv.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, Dec 06 2021, Jason Gunthorpe wrote: > On Mon, Dec 06, 2021 at 07:06:35PM +0100, Cornelia Huck wrote: > >> We're discussing a complex topic here, and we really don't want to >> perpetuate an unclear uAPI. This is where my push for more precise >> statements is coming from. > > I appreciate that, and I think we've made a big effort toward that > direction. > > Can we have some crisp feedback which statements need SHOULD/MUST/MUST > NOT and come to something? I'm not sure what I should actually comment on, some general remarks: - If we consider a possible vfio-ccw implementation that will quiesce the device and not rely on tracking I/O, we need to make the parts that talk about tracking non-mandatory. - NDMA sounds like something that needs to be non-mandatory as well. - The discussion regarding bit group changes has me confused. You seem to be saying that mlx5 needs that, so it needs to have some mandatory component; but are actually all devices able to deal with those bits changing as a group? - In particular, the flow needs definitive markings about what is mandatory to implement, what is strongly suggested, and what is optional. It is unclear to me what is really expected, and what is simply one way to implement it. > > The world needs to move forward, we can't debate this endlessly > forever. It is already another 6 weeks past since the last mlx5 driver > posting. 6 weeks is already blazingly fast in any vfio migration discussion. /s Remember that we have other things to do as well, not all of which will be visible to you.