From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MGDRc-00054K-5N for qemu-devel@nongnu.org; Mon, 15 Jun 2009 10:45:56 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MGDRY-00052I-1f for qemu-devel@nongnu.org; Mon, 15 Jun 2009 10:45:55 -0400 Received: from [199.232.76.173] (port=46663 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MGDRW-000529-Ic for qemu-devel@nongnu.org; Mon, 15 Jun 2009 10:45:50 -0400 Received: from g1t0029.austin.hp.com ([15.216.28.36]:15791) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MGDRW-00019G-3R for qemu-devel@nongnu.org; Mon, 15 Jun 2009 10:45:50 -0400 Subject: Re: [Qemu-devel] [PATCH] virtio-net: Remove RX_EXTRA feature From: Alex Williamson In-Reply-To: <200906151448.14205.rusty@rustcorp.com.au> References: <20090612191626.4227.7273.stgit@kvm.aw> <20090614093954.GB6959@redhat.com> <7162ab20906140631m3b6270e4w3dc7291388a94068@mail.gmail.com> <200906151448.14205.rusty@rustcorp.com.au> Content-Type: text/plain Date: Mon, 15 Jun 2009 08:45:44 -0600 Message-Id: <1245077144.4851.25.camel@lappy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Rusty Russell Cc: markmc@redhat.com, qemu-devel@nongnu.org, "Michael S. Tsirkin" On Mon, 2009-06-15 at 14:48 +0930, Rusty Russell wrote: > On Sun, 14 Jun 2009 11:01:37 pm Alex Williamson wrote: > > On Sun, Jun 14, 2009 at 3:39 AM, Michael S. Tsirkin wrote: > > > On Fri, Jun 12, 2009 at 01:17:04PM -0600, Alex Williamson wrote: > > >> No need to use a feature bit to identify the RX modes. The guest > > >> will get an error back if the backend doesn't support these controls. > > >> > > >> Signed-off-by: Alex Williamson > > > > > > What's the motivation here - are we running out of feature bits already? > > > Using feature bits for everything makes the interface more consistent > > > and IMO easier to use. > > > > See the thread starting here: > > > > http://lists.gnu.org/archive/html/qemu-devel/2009-06/msg00519.html > > > > Both Rusty and Mark voted against the feature bit. > > Not quite. I was unclear. I support the use of a feature bit. My question > is more meta. Oh, ok. Let's put this patch on hold then. > Features do need justification. (Not much, but some). It's hard to see the > use case where this feature offers significant advantages over promisc. Without > that, I'd wait until someone reports a need. Thanks for clarifying, a need has been reported. DMX is a proprietary OS that intends to run on KVM and make use of virtio-net. They would like to be able to toggle unicast and multicast independently as well as mask broadcast traffic. The original series re-arranged some of the filter code in the virtio-net backend that allows these filter options to drop out nicely. Thanks, Alex