From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH net-next 1/9] bpf: add BPF_J{LT,LE,SLT,SLE} instructions Date: Wed, 09 Aug 2017 19:00:58 +0200 Message-ID: <598B3FCA.7060904@iogearbox.net> References: <63b41a38e0d58536700c999ade7c2c267bd2613d.1502272924.git.daniel@iogearbox.net> <20170809.095553.268665355274669790.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: ast@fb.com, holzheu@linux.vnet.ibm.com, naveen.n.rao@linux.vnet.ibm.com, jakub.kicinski@netronome.com, netdev@vger.kernel.org To: David Miller Return-path: Received: from www62.your-server.de ([213.133.104.62]:37390 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754087AbdHIRBG (ORCPT ); Wed, 9 Aug 2017 13:01:06 -0400 In-Reply-To: <20170809.095553.268665355274669790.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 08/09/2017 06:55 PM, David Miller wrote: > From: Daniel Borkmann > Date: Wed, 9 Aug 2017 12:23:53 +0200 > >> [1] https://github.com/borkmann/llvm/tree/bpf-insns > > How is this "backwards compatible"? > > If someone takes a new LLVM and tries to load those programs > into an older kernel they will be rejected. > > There appears to be no effort to make things work cleanly in > that situation at all. No, that was just the patch I used for LLVM to enable the insns, so not the final one that will be submitted there officially where we have a switch to enable/disable this functionality.