Subject: Re: [PATCH net-next 1/9] bpf: add BPF_J{LT,LE,SLT,SLE} instructions

From: Daniel Borkmann <[email-masked]>
Date: Wed, 09 Aug 2017 19:03:03 +0200

On 08/09/2017 07:00 PM, Daniel Borkmann wrote:
> On 08/09/2017 06:55 PM, David Miller wrote:
>> From: Daniel Borkmann <[email-masked]>
>> 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.

(In other words the one I used for doing the measurements.)