From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MaXFk-0002GX-Ab for qemu-devel@nongnu.org; Mon, 10 Aug 2009 11:57:40 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MaXFf-0002Dj-Mn for qemu-devel@nongnu.org; Mon, 10 Aug 2009 11:57:40 -0400 Received: from [199.232.76.173] (port=54676 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MaXFf-0002DU-EV for qemu-devel@nongnu.org; Mon, 10 Aug 2009 11:57:35 -0400 Received: from mx2.redhat.com ([66.187.237.31]:42323) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MaXFe-00035W-UH for qemu-devel@nongnu.org; Mon, 10 Aug 2009 11:57:35 -0400 Message-ID: <4A804365.6010106@redhat.com> Date: Mon, 10 Aug 2009 17:57:25 +0200 From: Gerd Hoffmann 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> <4A802E35.1040308@codemonkey.ws> In-Reply-To: <4A802E35.1040308@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: Anthony Liguori Cc: kvm@vger.kernel.org, "Richard W.M. Jones" , Rusty Russell , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, Amit Shah 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