From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=53386 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PfbZ8-0002fD-LN for qemu-devel@nongnu.org; Wed, 19 Jan 2011 12:11:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PfbZ6-0002X6-MB for qemu-devel@nongnu.org; Wed, 19 Jan 2011 12:11:25 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:45925) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PfbZ6-0002Wx-Ek for qemu-devel@nongnu.org; Wed, 19 Jan 2011 12:11:24 -0500 Received: from d01dlp01.pok.ibm.com (d01dlp01.pok.ibm.com [9.56.224.56]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p0JGqDX6023831 for ; Wed, 19 Jan 2011 11:52:22 -0500 Received: from d01relay01.pok.ibm.com (d01relay01.pok.ibm.com [9.56.227.233]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id D3DBC729277 for ; Wed, 19 Jan 2011 11:53:34 -0500 (EST) Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay01.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p0JGrYZR396352 for ; Wed, 19 Jan 2011 11:53:34 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p0JGrYs6000970 for ; Wed, 19 Jan 2011 11:53:34 -0500 Message-ID: <4D37170A.20205@linux.vnet.ibm.com> Date: Wed, 19 Jan 2011 10:53:30 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state References: <4D2B6CB5.9050602@codemonkey.ws> <4D2B74D8.4080309@web.de> <4D2B8662.9060909@web.de> <4D2C60FB.7030009@linux.vnet.ibm.com> <4D2D80ED.8030405@redhat.com> <4D2D82EE.20002@siemens.com> <4D35A39A.8000801@siemens.com> <4D35ABF8.9050700@linux.vnet.ibm.com> <4D35B521.3090601@siemens.com> <4D35B6DD.1020005@linux.vnet.ibm.com> <4D35B963.7000605@siemens.com> <4D35BA22.7060602@linux.vnet.ibm.com> <4D35BD30.1060900@siemens.com> <4D35C1CE.10509@linux.vnet.ibm.com> <4D35C648.7050809@siemens.com> <4D35C92D.7030000@linux.vnet.ibm.com> <4D36B362.70202@redhat.com> In-Reply-To: <4D36B362.70202@redhat.com> 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: Gerd Hoffmann Cc: "kvm@vger.kernel.org" , Jan Kiszka , Glauber Costa , Marcelo Tosatti , Markus Armbruster , "qemu-devel@nongnu.org" , Avi Kivity On 01/19/2011 03:48 AM, Gerd Hoffmann wrote: > On 01/18/11 18:09, Anthony Liguori wrote: >> On 01/18/2011 10:56 AM, Jan Kiszka wrote: >>> >>>> The device model topology is 100% a hidden architectural detail. >>> This is true for the sysbus, it is obviously not the case for PCI and >>> similarly discoverable buses. There we have a guest-explorable topology >>> that is currently equivalent to the the qdev layout. >> >> But we also don't do PCI passthrough so we really haven't even explored >> how that maps in qdev. I don't know if qemu-kvm has attempted to >> qdev-ify it. > > It is qdev-ified. It is a normal pci device from qdev's point of view. > > BTW: is there any reason why (vfio-based) pci passthrough couldn't > work with tcg? > >> The -device interface is a stable interface. Right now, you don't >> specify any type of identifier of the pci bus when you create a PCI >> device. It's implied in the interface. > > Wrong. You can specify the bus you want attach the device to via > bus=. This is true for *every* device, including all pci > devices. If unspecified qdev uses the first bus it finds. > > As long as there is a single pci bus only there is simply no need to > specify it, thats why nobody does that today. Right. In terms of specifying bus=, what are we promising re: compatibility? Will there always be a pci.0? If we add some PCI-to-PCI bridges in order to support more devices, is libvirt support to parse the hierarchy and figure out which bus to put the device on? Regards, Anthony Liguori > Once q35 finally arrives this will change of course. > > cheers, > Gerd