From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MW3uO-000065-UR for qemu-devel@nongnu.org; Wed, 29 Jul 2009 03:49:08 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MW3uK-00005E-Ez for qemu-devel@nongnu.org; Wed, 29 Jul 2009 03:49:08 -0400 Received: from [199.232.76.173] (port=43369 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MW3uK-00005B-9D for qemu-devel@nongnu.org; Wed, 29 Jul 2009 03:49:04 -0400 Received: from mx20.gnu.org ([199.232.41.8]:41314) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MW3uJ-0001B9-QL for qemu-devel@nongnu.org; Wed, 29 Jul 2009 03:49:03 -0400 Received: from mx2.redhat.com ([66.187.237.31]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MW3uI-0002wT-Lo for qemu-devel@nongnu.org; Wed, 29 Jul 2009 03:49:03 -0400 Date: Wed, 29 Jul 2009 10:48:27 +0300 From: Gleb Natapov Subject: Re: [Qemu-devel] Re: virtio-serial: An interface for host-guest communication Message-ID: <20090729074827.GJ30449@redhat.com> References: <1248717876-17630-1-git-send-email-amit.shah@redhat.com> <4A6E0C9E.10908@codemonkey.ws> <20090727203214.GG15020@redhat.com> <20090727204627.GA32432@shareable.org> <4A6E3BDC.8050101@codemonkey.ws> <20090728103624.GA5176@amit-x200.redhat.com> <4A6F0048.1000103@codemonkey.ws> <20090729074418.GA24925@amit-x200.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090729074418.GA24925@amit-x200.redhat.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Amit Shah Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org On Wed, Jul 29, 2009 at 01:14:18PM +0530, Amit Shah wrote: > On (Tue) Jul 28 2009 [08:42:32], Anthony Liguori wrote: > > Amit Shah wrote: > >> Right; use virtio just as the transport and all the interesting > >> activity happens in userspaces. That was the basis with which I started. > >> I can imagine dbus doing the copy/paste, lock screen, etc. actions. > >> > >> However for libguestfs, dbus isn't an option and they already have some > >> predefined agents for each port. So libguestfs is an example for a > >> multi-port usecase for virtio-serial. > >> > > > > Or don't use dbus and use something that libguestfs is able to embed. > > The fact that libguestfs doesn't want dbus in the guest is not an > > argument for using a higher level kernel interface especially one that > > doesn't meet the requirements of the interface. > > But why do we want to limit the device to only one port? It's not too > complex supporting additional ones. > > As I see it qemu and the kernel should provide the basic abstraction for > the userspace to go do its job. Why create unnecessary barriers? > I agree. If userspace wants it may use only one channel and demultiplex messages by itself, but we shouldn't force it to. Also one of the requirements for virtio-serial is to have connect disconnect notifications. It is not possible with demultiplexing in the userspace. -- Gleb.