From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LzZGi-0006AO-JT for qemu-devel@nongnu.org; Thu, 30 Apr 2009 12:37:52 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LzZGe-00068H-6Q for qemu-devel@nongnu.org; Thu, 30 Apr 2009 12:37:52 -0400 Received: from [199.232.76.173] (port=51875 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LzZGd-00068A-Qq for qemu-devel@nongnu.org; Thu, 30 Apr 2009 12:37:47 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:49315) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LzZGd-0008QN-DV for qemu-devel@nongnu.org; Thu, 30 Apr 2009 12:37:47 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e2.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n3UGY5p2013726 for ; Thu, 30 Apr 2009 12:34:05 -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 v9.2) with ESMTP id n3UGbkUr152440 for ; Thu, 30 Apr 2009 12:37:46 -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 n3UGZtKM023182 for ; Thu, 30 Apr 2009 12:35:56 -0400 Message-ID: <49F9D3D8.3000704@us.ibm.com> Date: Thu, 30 Apr 2009 11:37:44 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [PATCH 9/9] Introduce VLANClientState::cleanup() References: <1239812969-8320-2-git-send-email-markmc@redhat.com> <200904301702.32282.paul@codesourcery.com> <49F9CFCA.8000002@redhat.com> <200904301731.04902.paul@codesourcery.com> <49F9D2BB.2060608@redhat.com> In-Reply-To: <49F9D2BB.2060608@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: Avi Kivity Cc: Mark McLoughlin , Marcelo Tosatti , Paul Brook , Markus Armbruster , qemu-devel@nongnu.org Avi Kivity wrote: > True, but is it actually useful? > > Short-circuiting two guest devices probably isn't. Adding host > devices (like recording packets) might be. But you can do this by just inserting yourself between the frontend/backend. You can do this dynamically as long as you don't require feature negotiation. Dynamic negotiation is prohibitively difficult and one of the primary reasons we haven't been able to merge vnet support for tap yet. The bus architecture is only useful if you want to generate and receive traffic on a vlan, not if you just want to record traffic. -- Regards, Anthony Liguori