Re: [PATCH v3 08/18] arm/arm64: KVM: Add PSCI version selection API

[Marc Zyngier]

On 05/02/18 10:50, Christoffer Dall wrote:
> On Mon, Feb 05, 2018 at 10:42:44AM +0000, Marc Zyngier wrote:
>> On 05/02/18 09:58, Andrew Jones wrote:
>>> On Mon, Feb 05, 2018 at 09:24:33AM +0000, Marc Zyngier wrote:
>>>> On 04/02/18 12:37, Christoffer Dall wrote:
>>
>> [...]
>>
>>>>> Given the urgency of adding mitigation towards variant 2 which is the
>>>>> driver for this work, I think we should drop the compat functionality in
>>>>> this series and work this out later on if needed.  I think we can just
>>>>> tweak the previous patch to enable PSCI 1.0 by default and drop this
>>>>> patch for the current merge window.
>>>>
>>>> I'd be fine with that, as long as we have a clear agreement on the
>>>> impact of such a move.
>>>
>>> Yeah, that's what I was trying to figure out with my fancy tables. I might
>>> be coming around more to your approach now, though. Ensuring the new->old
>>> migration fails is a nice feature of this series. It would be good if
>>> we could preserve that behavior without committing to a new userspace
>>> interface, but I'm not sure how. Maybe I should just apologize for the
>>> noise, and this patch be left as is...
>>
>> How about we don't decide now?
>>
>> I can remove this patch from the series so that the core stuff can make
>> it into the arm64 tree ASAP (I think Catalin wants to queue something
>> early this week so that it can hit Linus' tree before the end of the
>> merge window), and then repost this single patch on its own (with fixes
>> for the things that Christoffer found in his review) after -rc1.
>>
>> It leaves us time to haggle over the userspace ABI (which is
>> realistically not going to affect anyone), and we get the core stuff in
>> place for SoC vendors to start updating their firmware.
>>
> I agree, that's what I tried to suggest in my e-mail as well.  Just
> remember to tweak the previous patch to actually enable PSCI 1.0 by
> default.

Yup. I'll move the KVM_ARM_PSCI_LATEST hunk to that patch, and return it
unconditionally from kvm_psci_version.

	M.
-- 
Jazz is not dead. It just smells funny...