From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752963AbZIVCoN (ORCPT ); Mon, 21 Sep 2009 22:44:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752134AbZIVCoK (ORCPT ); Mon, 21 Sep 2009 22:44:10 -0400 Received: from ozlabs.org ([203.10.76.45]:33193 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752481AbZIVCoI (ORCPT ); Mon, 21 Sep 2009 22:44:08 -0400 From: Rusty Russell To: Alan Cox Subject: Re: [PATCH] virtio_console: Add support for multiple ports for generic guest and host communication Date: Tue, 22 Sep 2009 12:14:04 +0930 User-Agent: KMail/1.11.2 (Linux/2.6.28-15-generic; KDE/4.2.2; i686; ; ) Cc: Amit Shah , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <1252678386-17404-1-git-send-email-amit.shah@redhat.com> <1252678386-17404-2-git-send-email-amit.shah@redhat.com> <20090911170010.34c80f2d@linux.intel.com> In-Reply-To: <20090911170010.34c80f2d@linux.intel.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200909221214.04340.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 12 Sep 2009 01:30:10 am Alan Cox wrote: > > The interface presented to guest userspace is of a simple char > > device, so it can be used like this: > > > > fd = open("/dev/vcon2", O_RDWR); > > ret = read(fd, buf, 100); > > ret = write(fd, string, strlen(string)); > > > > Each port is to be assigned a unique function, for example, the > > first 4 ports may be reserved for libvirt usage, the next 4 for > > generic streaming data and so on. This port-function mapping > > isn't finalised yet. > > Unless I am missing something this looks completely bonkers > > Every time we have a table of numbers for functionality it ends in > tears. We have to keep tables up to date and managed, we have to > administer the magical number to name space. The number comes from the ABI; we need some identifier for the different ports. Amit started using names, and I said "just use numbers"; they have to be documented and agreed by all clients anyway. ie. the host says "here's a port id 7", which might be the cut & paste port or whatever. Cheers, Rusty.