Re: [PATCH v4 02/10] x86/vmx: add IPT cpu feature

[Michał Leszczyński <michal.leszczynski@xxxxxxx>]

----- 2 lip 2020 o 16:31, Julien Grall julien@xxxxxxx napisał(a):

> On 02/07/2020 15:17, Jan Beulich wrote:
>> On 02.07.2020 16:14, Julien Grall wrote:
>>> On 02/07/2020 14:30, Jan Beulich wrote:
>>>> On 02.07.2020 11:57, Julien Grall wrote:
>>>>> On 02/07/2020 10:18, Jan Beulich wrote:
>>>>>> On 02.07.2020 10:54, Julien Grall wrote:
>>>>>>> On 02/07/2020 09:50, Jan Beulich wrote:
>>>>>>>> On 02.07.2020 10:42, Julien Grall wrote:
>>>>>>>>> On 02/07/2020 09:29, Jan Beulich wrote:
>>>>> Another way to do it, would be the toolstack to do the mapping. At which
>>>>> point, you still need an hypercall to do the mapping (probably the
>>>>> hypercall acquire).
>>>>
>>>> There may not be any mapping to do in such a contrived, fixed-range
>>>> environment. This scenario was specifically to demonstrate that the
>>>> way the mapping gets done may be arch-specific (here: a no-op)
>>>> despite the allocation not being so.
>>> You are arguing on extreme cases which I don't think is really helpful
>>> here. Yes if you want to map at a fixed address in a guest you may not
>>> need the acquire hypercall. But in most of the other cases (see has for
>>> the tools) you will need it.
>>>
>>> So what's the problem with requesting to have the acquire hypercall
>>> implemented in common code?
>> 
>> Didn't we start out by you asking that there be as little common code
>> as possible for the time being?
> 
> Well as I said I am not in favor of having the allocation in common
> code, but if you want to keep it then you also want to implement
> map/unmap in the common code ([1], [2]).
> 
>> I have no issue with putting the
>> acquire implementation there ...
> This was definitely not clear given how you argued with extreme cases...
> 
> Cheers,
> 
> [1] <9a3f4d58-e5ad-c7a1-6c5f-42aa92101ca1@xxxxxxx>
> [2] <cf41855b-9e5e-13f2-9ab0-04b98f8b3cdd@xxxxxxx>
> 
> --
> Julien Grall


Guys,

could you express your final decision on this topic?

While I understand the discussion and the arguments you've raised,
I would like to know what particular elements should be moved where.

So are we going abstract way, or non-abstract-x86 only way?

Best regards,
Michał Leszczyński
CERT Polska