From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC PATCH] vfio: VFIO PCI driver for Qemu Date: Thu, 26 Jul 2012 11:35:47 +0300 Message-ID: <50110163.30209@redhat.com> References: <20120725165948.17260.82862.stgit@bling.home> <50104973.3090302@redhat.com> <1343246026.2229.374.camel@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, aik@ozlabs.ru, benh@kernel.crashing.org To: Alex Williamson Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63896 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981Ab2GZIfy (ORCPT ); Thu, 26 Jul 2012 04:35:54 -0400 In-Reply-To: <1343246026.2229.374.camel@bling.home> Sender: kvm-owner@vger.kernel.org List-ID: On 07/25/2012 10:53 PM, Alex Williamson wrote: > On Wed, 2012-07-25 at 22:30 +0300, Avi Kivity wrote: >> On 07/25/2012 08:03 PM, Alex Williamson wrote: >> > This adds PCI based device assignment to Qemu using the Linux VFIO >> > userspace driver interface. After setting up VFIO device access, >> > devices can be added to Qemu guests using the vfio-pci device >> > option: >> > >> > -device vfio-pci,host=1:10.1,id=net0 >> > >> > >> >> Let's use the same syntax as for kvm device assignment. Then we can >> fall back on kvm when vfio is not available. We can also have an >> optional parameter kernel-driver to explicitly select vfio or kvm. > > This seems confusing to me, pci-assign already has options like > prefer_msi, share_intx, and configfd that vfio doesn't. I'm sure vfio > will eventually get options that pci-assign won't have. How is a user > supposed to figure out what options are actually available from -device > pci-assign,? Read the documentation. > Isn't this the same as asking to drop all model specific > devices and just use -device net,model=e1000... hey, we've been there > before ;) Thanks, It's not. e1000 is a guest visible feature. vfio and kvm assignment do exactly the same thing, as far as the guest is concerned, just using a different driver. This is more akin to -device virtio-net,vhost=on|off (where we also have a default and a fallback, which wouldn't make sense for model=e1000). -- error compiling committee.c: too many arguments to function