Re: [PATCH v2 0/8] x86/PV: avoid speculation abuse through guest accessors

[Jan Beulich <jbeulich@suse.com>]

On 24.02.2021 14:08, Ian Jackson wrote:
> Jan Beulich writes ("Re: [PATCH v2 0/8] x86/PV: avoid speculation abuse through guest accessors"):
>> On 19.02.2021 16:50, Ian Jackson wrote:
>>> Jan Beulich writes ("[PATCH v2 0/8] x86/PV: avoid speculation abuse through guest accessors"):
>>>> 4: rename {get,put}_user() to {get,put}_guest()
>>>> 5: gdbsx: convert "user" to "guest" accesses
>>>> 6: rename copy_{from,to}_user() to copy_{from,to}_guest_pv()
>>>> 7: move stac()/clac() from {get,put}_unsafe_asm() ...
>>>> 8: PV: use get_unsafe() instead of copy_from_unsafe()
>>>
>>> These have not got a maintainer review yet.  To grant a release-ack
>>> I'd like an explanation of the downsides and upsides of taking this
>>> series in 4.15 ?
>>>
>>> You say "consistency" but in practical terms, what will happen if the
>>> code is not "conxistent" in this sense ?
>>>
>>> I'd also like to hear from aother hypervisor maintainer.
>>
>> Meanwhile they have been reviewed by Roger. Are you willing to
>> give them, perhaps with the exception of 7, a release ack as
>> well?
> 
> Sorry, yes.
> 
> I found these explanations convincing  Thank you.
> 
> For all except 7,
> Release-Acked-by: Ian Jackson <iwj@xenproject.org>

Thanks.

> For 7, I remember what I think was an IRC conversation where someone
> (you, I think) said you had examined the generated asm and it was
> unchanged.

It was in email, and I've inspected only some example of the
generated asm, not all instances. I would hope that was
sufficient, but since I'm not entirely certain ...

> If I have remembered that correctly, then for 7 as well:
> Release-Acked-by: Ian Jackson <iwj@xenproject.org>

... I'll better wait for explicit confirmation of this.

Jan