From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [Qemu-devel] Re: virtio-serial: An interface for host-guest communication Date: Mon, 10 Aug 2009 17:57:25 +0200 Message-ID: <4A804365.6010106@redhat.com> 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> <4A802E35.1040308@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: Anthony Liguori Return-path: Received: from mx2.redhat.com ([66.187.237.31]:48188 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbZHJP5g (ORCPT ); Mon, 10 Aug 2009 11:57:36 -0400 In-Reply-To: <4A802E35.1040308@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On 08/10/09 16:27, Anthony Liguori wrote: > I think my fundamental argument boils down to two points. 1) we should > not require new guest drivers unless we absolutely have to Allow guest drivers is fine though I guess? > 2) we should > always do things in userspace unless we absolutely have to do things in > the kernel. Wrong. There are often good reasons to do stuff in kernel, even if you can do it in userspace too. > Adding new kernel drivers breaks support for enterprise Linux distros. > Adding a userspace daemon does not. Windows device drivers require > signing which is very difficult to do. There's a huge practical > advantage in not requiring guest drivers. Ok, so the virtio-serial + usbserial combo should work well then I think. If you have guest drivers you'll go the virtio-serial route. If you don't have guest drivers you can go the usbserial route, either via /dev/ttyUSB or via libusb. We can also have a libvmchannel as abstraction layer on top of this. cheers, Gerd