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=-0.8 required=3.0 tests=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 E3D00CA9EB0 for ; Sun, 3 Nov 2019 10:10:58 +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 A374B20842 for ; Sun, 3 Nov 2019 10:10:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=hostfission.com header.i=@hostfission.com header.b="eaBFp4NQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A374B20842 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=hostfission.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52894 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iRCqX-0003p8-R1 for qemu-devel@archiver.kernel.org; Sun, 03 Nov 2019 05:10:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:47333) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iRCpt-0003NF-Dv for qemu-devel@nongnu.org; Sun, 03 Nov 2019 05:10:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iRCps-0006Kj-AM for qemu-devel@nongnu.org; Sun, 03 Nov 2019 05:10:17 -0500 Received: from mail1.hostfission.com ([139.99.139.48]:39938) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1iRCpr-0006Jq-Vb for qemu-devel@nongnu.org; Sun, 03 Nov 2019 05:10:16 -0500 Received: from www1.hostfission.com (www1.hostfission.com [139.99.139.52]) by mail1.hostfission.com (Postfix) with ESMTP id 23FD04BBBD; Sun, 3 Nov 2019 21:10:11 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hostfission.com; s=mail; t=1572775811; bh=X7WBWM6sJzXJgiNWbuZs8C70M3jPlIalBOwRPlXa/k0=; h=To:Subject:Date:From:Cc:In-Reply-To:References:From; b=eaBFp4NQYutUMncxhP+hspgbAsrbaBguRu+kCHT8/eqBE7/71SRb5vLqwPIly8vur XWy72ec5oi7EqBHt0J8oqOAZHFUzoa+dFmFhgwvYBwWXefolDuvZGygLbIG4o9r8uA erAPqAw7BNwOnk87fDxLPnHQOp3QPe3i4oP0HUNQ= Received: by www1.hostfission.com (Postfix, from userid 1000) id 0B26080CBF; Sun, 3 Nov 2019 21:10:11 +1100 (AEDT) To: "Dr. David Alan Gilbert" Subject: Re: RFC: New device for zero-copy VM memory access X-PHP-Originating-Script: 0:rcube.php MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Sun, 03 Nov 2019 21:10:10 +1100 From: geoff@hostfission.com Cc: Peter Maydell , QEMU Developers In-Reply-To: <20191031155204.GD3128@work-vm> References: <20191030185248.GC3114@work-vm> <88f1c3701740665b0ebe2f24c8ce7ade@hostfission.com> <20191031132443.GB3128@work-vm> <20191031155204.GD3128@work-vm> Message-ID: X-Sender: geoff@hostfission.com User-Agent: Roundcube Webmail/1.2.3 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 139.99.139.48 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2019-11-01 02:52, Dr. David Alan Gilbert wrote: > * geoff@hostfission.com (geoff@hostfission.com) wrote: >> >> >> On 2019-11-01 01:52, Peter Maydell wrote: >> > On Thu, 31 Oct 2019 at 14:26, wrote: >> > > As the author of Looking Glass, I also have to consider the >> > > maintenance >> > > and the complexity of implementing the vhost protocol into the >> > > project. >> > > At this time a complete Porthole client can be implemented in 150 >> > > lines >> > > of C without external dependencies, and most of that is boilerplate >> > > socket code. This IMO is a major factor in deciding to avoid >> > > vhost-user. >> > >> > This is essentially a proposal that we should make our project and >> > code more complicated so that your project and code can be simpler. >> > I hope you can see why this isn't necessarily an argument that will hold >> > very much weight for us :-) >> >> Certainly, I do which is why I am still going to see about using >> vhost, >> however, a device that uses vhost is likely more complex then the >> device >> as it stands right now and as such more maintenance would be involved >> on >> your end also. Or have I missed something in that vhost-user can be >> used >> directly as a device? > > The basic vhost-user stuff isn't actually that hard; if you aren't > actually shuffling commands over the queues you should find it pretty > simple - so I think your assumption about it being simpler if you avoid > it might be wrong. It might be easier if you use it! I have been looking into this and I am yet to find some decent documentation or a simple device example I can use to understand how to create such a device. Do you know of any reading or examples I can obtain on how to get an initial do nothing device up and running? -Geoff > > Dave > >> > >> > thanks >> > -- PMM > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK