From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KiBD1-00056y-Lo for qemu-devel@nongnu.org; Tue, 23 Sep 2008 12:57:55 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KiBD0-00056Z-6x for qemu-devel@nongnu.org; Tue, 23 Sep 2008 12:57:55 -0400 Received: from [199.232.76.173] (port=42677 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KiBD0-00056V-38 for qemu-devel@nongnu.org; Tue, 23 Sep 2008 12:57:54 -0400 Received: from mail.uni-ulm.de ([134.60.1.11]:47594) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1KiBCy-000146-Bk for qemu-devel@nongnu.org; Tue, 23 Sep 2008 12:57:53 -0400 Received: from [134.60.208.125] (pc25.informatik.uni-ulm.de [134.60.208.125]) (authenticated bits=0) by mail.uni-ulm.de (8.14.2/8.14.2) with ESMTP id m8NGvf9I012751 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Tue, 23 Sep 2008 18:57:49 +0200 (MEST) Message-ID: <48D92005.8070606@uni-ulm.de> Date: Tue, 23 Sep 2008 18:57:41 +0200 From: Martin Rauh MIME-Version: 1.0 Subject: Re: [Qemu-devel] jumbo frames: needing some help References: <20080919193742.vp0rkod868o0g84o@imap.uni-ulm.de> <48D3F66D.2080507@codemonkey.ws> <48D55D13.2050006@uni-ulm.de> <48D7F519.1020808@codemonkey.ws> In-Reply-To: <48D7F519.1020808@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Anthony Liguori wrote: > Martin Rauh wrote: >> Anthony Liguori wrote: >>> martin.rauh@uni-ulm.de wrote: >>>> Hello, everyone! >>>> >>>> Sorry for the inconvenience, but as a part of my diploma thesis, I >>>> am creating a virtual NIC for QEMU, in order to support a new >>>> cluster OS of the university. (Saving the overhead caused by >>>> emulating real hardware, it is not emulating an existing NIC.) >>>> Anyway, now it seems to be working correctly, except for handling >>>> jumbo frames, which I have to make available. >>> >>> You would have to post your patch. We seem to be able to handle >>> jumbo frames nicely with virtio-net. >>> >>> BTW, are you aware of virtio-net? It has all of the properties that >>> you are describing and it already exists for Linux and Windows. >>> >> No, I didn't know about virtio-net. Presumably it would be better to >> support this virtio-net in our OS, but I think there's not enough time >> left to develop a new driver now. I will recommend this for further >> proceeding, thank you for this hint! >> >> http://home.vrweb.de/mrauh/testnic.c >> Here is the source file of my virtual NIC, which I modelled on then >> NE2000.c, but it is probably not very nice to read. I used >> qemu_send_packet for sending and registered my testnic_receive >> function via qemu_new_vlan_client. Do you agree in principle to this >> approach, in terms of proceeding jumbo frames? > > Well if you don't have a patch to vl.c, that's probably your problem. > There are a number of spots in the VLAN send functions that use buffers > of 4096. You won't be able to receive a packet larger than that. > You are right, this was the Problem! I can't believe that I didn't see it, while I spent so many time on searching for. Thanks a lot! Best wishes, Martin Rauh.