From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MxNoJ-0004W7-NA for qemu-devel@nongnu.org; Mon, 12 Oct 2009 12:31:48 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MxNoD-0004PL-O9 for qemu-devel@nongnu.org; Mon, 12 Oct 2009 12:31:46 -0400 Received: from [199.232.76.173] (port=47343 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MxNoD-0004PG-K0 for qemu-devel@nongnu.org; Mon, 12 Oct 2009 12:31:41 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:48831) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MxNoD-0001dQ-Ak for qemu-devel@nongnu.org; Mon, 12 Oct 2009 12:31:41 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e9.ny.us.ibm.com (8.14.3/8.13.1) with ESMTP id n9CGRxl2026282 for ; Mon, 12 Oct 2009 12:27:59 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n9CGVbUH236010 for ; Mon, 12 Oct 2009 12:31:37 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n9CGSBh0003303 for ; Mon, 12 Oct 2009 12:28:11 -0400 Message-ID: <4AD359E6.50108@us.ibm.com> Date: Mon, 12 Oct 2009 11:31:34 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [PATCH v2 9/9] Add -kvm option References: <1254953315-5761-2-git-send-email-glommer@redhat.com> <1254953315-5761-3-git-send-email-glommer@redhat.com> <1254953315-5761-4-git-send-email-glommer@redhat.com> <1254953315-5761-5-git-send-email-glommer@redhat.com> <1254953315-5761-6-git-send-email-glommer@redhat.com> <1254953315-5761-7-git-send-email-glommer@redhat.com> <1254953315-5761-8-git-send-email-glommer@redhat.com> <1254953315-5761-9-git-send-email-glommer@redhat.com> <1254953315-5761-10-git-send-email-glommer@redhat.com> <4ACD1D92.8080607@us.ibm.com> <20091007231405.GQ8092@mothafucka.localdomain> <4ACD2414.9000401@codemonkey.ws> <4AD319F6.70506@redhat.com> <4AD33774.1030001@us.ibm.com> <4AD34C75.8090803@redhat.com> In-Reply-To: <4AD34C75.8090803@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: Glauber Costa , qemu-devel@nongnu.org Gerd Hoffmann wrote: > On 10/12/09 16:04, Anthony Liguori wrote: >> Gerd Hoffmann wrote: >>> -M $machine gives you a barebone machine with all core devices which >>> belong to it. You can't easily remove and/or replace devices. >>> Especially not something central as the IRQ controller. But also no >>> other core components, i.e. you wouldn't stick a piix4 ide controller >>> into a Q35 machine. Just say 'no'. >> >> This seems fundamentally flawed to me. If you cannot remove a device >> from a machine using command line options, then how do we support >> something like -net none? > > '-net none' does not remove a nic. It makes qemu not add the default > nic. qemu should not have the concept of a default nic. Instead, if you choose the pc machine type, by default you get an e1000. I think it's also reasonable to get a USB controller too along with the balloon driver and anything else we think a user could benefit from. If you give devices well known ids, then changing a default device is not really that big of a deal. It involves removing the device and adding a new device with that same device id. For platform devices, like the interrupt controller/pic, the same principle could be applied to switch out a userspace irqchip/pit with the kvm kernel implementations. -- Regards, Anthony Liguori