[PATCH v3 0/2] PSCI system off and reset for KVM ARM/ARM64

[anup@brainfault.org (Anup Patel)]

On Wed, Dec 18, 2013 at 9:11 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> Hi Anup,
>
> On Wed, Dec 18 2013 at 03:03:43 PM, Anup Patel <anup@brainfault.org> wrote:
>> On Wed, Dec 18, 2013 at 8:08 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
>>> Christoffer Dall <christoffer.dall@linaro.org> writes:
>>>
>>>> On Tue, Dec 17, 2013 at 05:05:34PM +0530, Anup Patel wrote:
>>>>> The Power State and Coordination Interface (PSCI) specification defines
>>>>> SYSTEM_OFF and SYSTEM_RESET functions for system poweroff and reboot.
>>>>>
>>>>> This patchset adds emulation of PSCI SYSTEM_OFF and SYSTEM_RESET functions
>>>>> in KVM ARM/ARM64 by forwarding them to user space (QEMU or KVMTOOL) using
>>>>> KVM_EXIT_SYSTEM_EVENT exit reason.
>>>>>
>>>>> To try this patch from guest kernel, we will need PSCI-based restart and
>>>>> poweroff support in the guest kenel for both ARM and ARM64.
>>>>>
>>>>> Rob Herring has already submitted patches for PSCI-based restart and
>>>>> poweroff in ARM kernel but these are not merged yet due unstable device
>>>>> tree bindings of kernel PSCI support. We will be having similar patches
>>>>> for PSCI-based restart and poweroff in ARM64 kernel.
>>>>> (Refer http://www.spinics.net/lists/arm-kernel/msg262217.html)
>>>>> (Refer http://www.spinics.net/lists/devicetree/msg05348.html)
>>>>
>>>> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
>>>>
>>>> I can merge this series if Marc acks it as well.
>>>
>>> The patches themselves are mostly fine. One issue though: They implement
>>> part of the v0.2 spec, but keep on using the range of function IDs that
>>> we made up for v0.1.
>>>
>>> I just had a chat with the person responsible for the spec, and realized
>>> that the Function IDs mentionned in the v0.2 spec are not optional, and
>>> not using them would be in direct violation of the spec (the new numbers
>>> now come directly from the SMC calling convention).
>>
>> Should we emulate PSCI_VERSION call to help Guest determine
>> the spec version emulated by KVM (i.e. v0.1 or v0.2) ??
>
> I think that'd be a nice to have, but the guest is likely to get its
> information from the DT anyway. Plus I don't think the original PSCI
> spec specified PSCI_VERSION, which only make it useful for whatever
> comes after v0.2.
>
> So I think we need to:
> - Use the new range for PSCI v0.2 (while still supporting v0.1 and the
> old range)

Does this mean we should have first isolate v0.2 ID range
from v0.1 ID range?

And then...

Rebase this patchset based on new v0.2 ID range?

> - Get the kernel and DT bindings into shape
> - Merge all of that at the same time
>
> Cheers,
>
>         M.
> --
> Jazz is not dead. It just smells funny.