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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 B4A03CA9ECB for ; Thu, 31 Oct 2019 15:58:44 +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 7C3DC2087F for ; Thu, 31 Oct 2019 15:58:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Scd5hrUF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C3DC2087F 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]:51736 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iQCqP-0004m0-Fr for qemu-devel@archiver.kernel.org; Thu, 31 Oct 2019 11:58:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60768) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iQCkD-00067d-7P for qemu-devel@nongnu.org; Thu, 31 Oct 2019 11:52:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iQCkB-0008Oo-HK for qemu-devel@nongnu.org; Thu, 31 Oct 2019 11:52:16 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:31172 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iQCkB-0008Lk-A6 for qemu-devel@nongnu.org; Thu, 31 Oct 2019 11:52:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1572537134; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/5SVsKScJzxtB1/7M2yHvL15ehF1kCrtK9L+g/fHU74=; b=Scd5hrUF6YkRCIwCeBiDJbfvpVZC8eTURmT18NFvzaGzGi6OBAHVL/1ko5JweFKNOd2dEW fTqU5pH6gmmOXaDPiBhtV1C7rEFcaD5sf2lQXvXwrcS1Y7fa8+adzc12hl7cBBTEXe7A78 AeM8Ii/db0EwnP9jcwty23JGQlceKQs= 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-256-jbuahQc9Nua-Rwa_QgSjDw-1; Thu, 31 Oct 2019 11:52:09 -0400 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 4DCAC1800D56; Thu, 31 Oct 2019 15:52:08 +0000 (UTC) Received: from work-vm (ovpn-116-247.ams2.redhat.com [10.36.116.247]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 264EE19C7F; Thu, 31 Oct 2019 15:52:06 +0000 (UTC) Date: Thu, 31 Oct 2019 15:52:04 +0000 From: "Dr. David Alan Gilbert" To: geoff@hostfission.com Subject: Re: RFC: New device for zero-copy VM memory access Message-ID: <20191031155204.GD3128@work-vm> References: <20191030185248.GC3114@work-vm> <88f1c3701740665b0ebe2f24c8ce7ade@hostfission.com> <20191031132443.GB3128@work-vm> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: jbuahQc9Nua-Rwa_QgSjDw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: Peter Maydell , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * geoff@hostfission.com (geoff@hostfission.com) wrote: >=20 >=20 > 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. > >=20 > > 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 hol= d > > very much weight for us :-) >=20 > 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! Dave > >=20 > > thanks > > -- PMM -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK