Re: Xen XSM/FLASK policy, grub defaults, etc.

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.05.2020 19:24, Julien Grall wrote:
> On 29/05/2020 16:11, Jan Beulich wrote:
>> On 29.05.2020 17:05, Julien Grall wrote:
>>> On 29/05/2020 15:47, Ian Jackson wrote:
>>>> George Dunlap writes ("Re: Xen XSM/FLASK policy, grub defaults, etc."):
>>>>> Which isn’t to say we shouldn’t do it; but it might be nice to also have 
>>>>> an intermediate solution that works right now, even if it’s not optimal.
>>>>
>>>> I propose the following behaviour by updste-grub:
>>>>
>>>>    1. Look for an ELF note, TBD.  If it's found, make XSM boot entries.
>>>>       (For now, skip this step, since the ELF note is not defined.)
>>>
>>> I am afraid the ELF note is a very x86 thing. On Arm, we don't have such
>>> thing for the kernel/xen (actually the final binary is not even an ELF).
>>
>> Ouch - of course. Is there anything similar one could employ there?
> 
> In the past, we discussed about adding support for note in the zImage 
> (arm32 kernel format) but I never got the chance to pursue the discussion.
> 
> With Juergen's hypfs series, the hypervisor now embbed the .config. Is 
> it possible to extract it?

How easy is it to reliably find a random blob of gzip-ed data in an
otherwise unstructured (as in: no ELF sections, and hence no way to
put the data of interest into a separate section for easy
recognition) binary? Also don't forget that the embedding of .config
is an optional thing.

Jan