From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Event channels in KVM? Date: Tue, 23 Sep 2008 10:26:56 +0300 Message-ID: <48D89A40.6030109@redhat.com> References: <11b8bea70809191016v4d38ad0fma3e51273e7108237@mail.gmail.com> <48D3F01D.7070600@codemonkey.ws> <90eb1dc70809191210s6a10ce17ke1dc8663169f037a@mail.gmail.com> <48D3FA05.7000101@codemonkey.ws> <11b8bea70809221650u59a15347sc7f867a25f035d1d@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Javier Guerra , kvm@vger.kernel.org To: Matt Anger Return-path: Received: from mx2.redhat.com ([66.187.237.31]:40492 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751465AbYIWH1I (ORCPT ); Tue, 23 Sep 2008 03:27:08 -0400 In-Reply-To: <11b8bea70809221650u59a15347sc7f867a25f035d1d@mail.gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: Matt Anger wrote: > Thanks for the info, I've been looking into it by trying to look > around kvm source code. > Apparently I have to write a kernel driver for the guest os and then > also write backend driver and modify qemu to use it? Is that correct? > That seems ugly, especially since now my io goes guest->guest kernel > driver->host kernel kvm->qemu->host kernel driver.... > With Xen event-channels my driver gets the event notification directly > with no user space intervention removing the middle 2 steps and I > don't have to touch any of Xen's codebase. My driver just registers > for an event-channel. > The qemu device in kvm is equivalent to the dom0 backend driver. kvm's qemu is equivalent to Xen's dom0. The guest kernel driver in kvm is equivalent to the domU kernel driver. Event channels map to interrupts (host->guest) and mmio/pio (guest/host); virtio provides an abstraction on top of that. -- error compiling committee.c: too many arguments to function