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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 488ADC433DF for ; Mon, 8 Jun 2020 10:15:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2CC6D20760 for ; Mon, 8 Jun 2020 10:15:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729307AbgFHKPc (ORCPT ); Mon, 8 Jun 2020 06:15:32 -0400 Received: from mga14.intel.com ([192.55.52.115]:58679 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726660AbgFHKPc (ORCPT ); Mon, 8 Jun 2020 06:15:32 -0400 IronPort-SDR: aQXo931Nlb2H3iNr5z33nmx9g6+b6Mgw0uFjEAgXPnKTnCrUNCUkQIE0H6Dpj7BI4dlny8er1e NbAFQV6nJF3w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2020 03:15:31 -0700 IronPort-SDR: m0FFRdLHaD/Vf/qbUvK66+JEM9UMrfJC4RA8ihb9+yJuwDroGvqbp5FWkEHCrvfcu1QtugZxaK /zBYHZ20WgcA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,487,1583222400"; d="scan'208";a="446683561" Received: from gliakhov-mobl2.ger.corp.intel.com (HELO ubuntu) ([10.249.46.212]) by orsmga005.jf.intel.com with ESMTP; 08 Jun 2020 03:15:28 -0700 Date: Mon, 8 Jun 2020 12:15:27 +0200 From: Guennadi Liakhovetski To: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org, linux-remoteproc@vger.kernel.org, virtualization@lists.linux-foundation.org, sound-open-firmware@alsa-project.org, Pierre-Louis Bossart , Liam Girdwood , Jason Wang , Ohad Ben-Cohen , Bjorn Andersson , Mathieu Poirier Subject: Re: [PATCH v3 0/5] Add a vhost RPMsg API Message-ID: <20200608101526.GD10562@ubuntu> References: <20200527180541.5570-1-guennadi.liakhovetski@linux.intel.com> <20200604151917-mutt-send-email-mst@kernel.org> <20200605063435.GA32302@ubuntu> <20200608073715.GA10562@ubuntu> <20200608091100.GC10562@ubuntu> <20200608051358-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200608051358-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Jun 08, 2020 at 05:19:06AM -0400, Michael S. Tsirkin wrote: > On Mon, Jun 08, 2020 at 11:11:00AM +0200, Guennadi Liakhovetski wrote: > > Update: I looked through VirtIO 1.0 and 1.1 specs, data format their, > > including byte order, is defined on a per-device type basis. RPMsg is > > indeed included in the spec as device type 7, but that's the only > > mention of it in both versions. It seems RPMsg over VirtIO isn't > > standardised yet. > > Yes. And it would be very good to have some standartization before we > keep adding things. For example without any spec if host code breaks > with some guests, how do we know which side should be fixed? > > > Also it looks like newer interface definitions > > specify using "guest native endianness" for Virtual Queue data. > > They really don't or shouldn't. That's limited to legacy chapters. > Some definitions could have slipped through but it's not > the norm. I just quickly looked through the 1.1 spec and could > not find any instances that specify "guest native endianness" > but feel free to point them out to me. Oh, there you go. No, sorry, my fault, it's the other way round: "guest native" is for legacy and LE is for current / v1.0 and up. > > So > > I think the same should be done for RPMsg instead of enforcing LE? > > That makes hardware implementations as well as any cross-endian > hypervisors tricky. Yes, LE it is then. And we need to add some text to the spec. In theory there could be a backward compatibility issue - in case someone was already using virtio_rpmsg_bus.c in BE mode, but I very much doubt that... Thanks Guennadi