From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] Re: virtio-serial: An interface for host-guest communication Date: Mon, 10 Aug 2009 12:27:03 -0500 Message-ID: <4A805867.503@codemonkey.ws> References: <20090805175713.GB28738@shareable.org> <4A79C8D9.5030606@codemonkey.ws> <20090806103843.GC9222@amit-x200.redhat.com> <4A7ADAC4.70902@codemonkey.ws> <20090806134103.GC11733@amit-x200.redhat.com> <4A7AE169.4000606@codemonkey.ws> <20090806140404.GA12083@amit-x200.redhat.com> <20090806173740.GA1178@shareable.org> <20090807063800.GA16769@amit-x200.redhat.com> <4A7C36D3.3040305@codemonkey.ws> <20090810065508.GA4499@amit-x200.redhat.com> <4A7FECCA.8080804@redhat.com> <4A801A7B.1020208@codemonkey.ws> <4A80287C.7050400@redhat.com> <4A802CA7.9020701@codemonkey.ws> <4A803E07.7080407@redhat.com> <4A8051F3.7040400@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Amit Shah , kvm@vger.kernel.org, qemu-devel@nongnu.org, Rusty Russell , "Richard W.M. Jones" , virtualization@lists.linux-foundation.org To: Gerd Hoffmann Return-path: Received: from qw-out-2122.google.com ([74.125.92.26]:12601 "EHLO qw-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932242AbZHJR1G (ORCPT ); Mon, 10 Aug 2009 13:27:06 -0400 Received: by qw-out-2122.google.com with SMTP id 8so1208859qwh.37 for ; Mon, 10 Aug 2009 10:27:07 -0700 (PDT) In-Reply-To: <4A8051F3.7040400@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: Anthony Liguori wrote: > > There is nothing sane about vmchannel. It's just an attempt to bypass > QEMU which is going to introduce all sorts of complexities wrt > migration, guest compatibility, etc. > > However, as I've mentioned repeatedly, the reason I won't merge > virtio-serial is that it duplicates functionality with > virtio-console. If the two are converged, I'm happy to merge it. I'm > not opposed to having more functionality. NB: the userspace interface for these devices should be a tty, not a new character device. If you want to add a new bustype for these devices, and then have an entry in sysfs that had some sort of identification string, that's perfectly acceptable. Also note though that this is exactly what usb-serial is today. /sys/bus/usbserial contains all the usb serial devices and you can get a vendor id/device id to uniquely identify the device type. Using virtio vs. usb has it's advantage but the userspace interface model should be roughly equivalent. Regards, Anthony Liguori From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MaYeQ-00029d-6m for qemu-devel@nongnu.org; Mon, 10 Aug 2009 13:27:14 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MaYeL-00028L-05 for qemu-devel@nongnu.org; Mon, 10 Aug 2009 13:27:13 -0400 Received: from [199.232.76.173] (port=49866 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MaYeK-00028H-TD for qemu-devel@nongnu.org; Mon, 10 Aug 2009 13:27:08 -0400 Received: from mail-qy0-f174.google.com ([209.85.221.174]:57978) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MaYeK-0000WO-0k for qemu-devel@nongnu.org; Mon, 10 Aug 2009 13:27:08 -0400 Received: by qyk4 with SMTP id 4so2621212qyk.4 for ; Mon, 10 Aug 2009 10:27:07 -0700 (PDT) Message-ID: <4A805867.503@codemonkey.ws> Date: Mon, 10 Aug 2009 12:27:03 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: virtio-serial: An interface for host-guest communication References: <20090805175713.GB28738@shareable.org> <4A79C8D9.5030606@codemonkey.ws> <20090806103843.GC9222@amit-x200.redhat.com> <4A7ADAC4.70902@codemonkey.ws> <20090806134103.GC11733@amit-x200.redhat.com> <4A7AE169.4000606@codemonkey.ws> <20090806140404.GA12083@amit-x200.redhat.com> <20090806173740.GA1178@shareable.org> <20090807063800.GA16769@amit-x200.redhat.com> <4A7C36D3.3040305@codemonkey.ws> <20090810065508.GA4499@amit-x200.redhat.com> <4A7FECCA.8080804@redhat.com> <4A801A7B.1020208@codemonkey.ws> <4A80287C.7050400@redhat.com> <4A802CA7.9020701@codemonkey.ws> <4A803E07.7080407@redhat.com> <4A8051F3.7040400@codemonkey.ws> In-Reply-To: <4A8051F3.7040400@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: kvm@vger.kernel.org, "Richard W.M. Jones" , Rusty Russell , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, Amit Shah Anthony Liguori wrote: > > There is nothing sane about vmchannel. It's just an attempt to bypass > QEMU which is going to introduce all sorts of complexities wrt > migration, guest compatibility, etc. > > However, as I've mentioned repeatedly, the reason I won't merge > virtio-serial is that it duplicates functionality with > virtio-console. If the two are converged, I'm happy to merge it. I'm > not opposed to having more functionality. NB: the userspace interface for these devices should be a tty, not a new character device. If you want to add a new bustype for these devices, and then have an entry in sysfs that had some sort of identification string, that's perfectly acceptable. Also note though that this is exactly what usb-serial is today. /sys/bus/usbserial contains all the usb serial devices and you can get a vendor id/device id to uniquely identify the device type. Using virtio vs. usb has it's advantage but the userspace interface model should be roughly equivalent. Regards, Anthony Liguori