[PATCH 2/3] KVM: arm/arm64: Add ARM arch timer interrupts ABI

[Peter Maydell]

On 1 November 2016 at 14:50, Christoffer Dall
<christoffer.dall at linaro.org> wrote:
> On Tue, Nov 01, 2016 at 11:26:54AM +0000, Peter Maydell wrote:
>> Possible current and future outbound interrupt lines (some of these
>> would only show up in some unlikely or lots-of-implementation-needed
>> cases, I'm just trying to produce an exhaustive list):
>>  * virtual timer
>>  * physical timer
>>  * hyp timer (nested virtualization case)
>>  * secure timer (unlikely but maybe if EL3 is ever supported inside a VM)
>>  * gic maintenance interrupt (nested virt again)
>>  * PMU interrupt
>
> Thanks for the list, that's good to have around for the future.
>
> There's also the potential of the EL2 virtual timer for nested VHE
> support, right?

That's the one I meant by "hyp timer".

>> The kernel doesn't know which interrupt number these would be wired
>> up to, so they're all just arbitrary outputs, and you could put them
>> in one field or split them up into multiple fields, it doesn't make
>> much difference.
>>
>
> So if we keep this we're kind of suggesting that we'll have a field per
> device type later on.  Since this is a u8 and we are talking about up 5
> 5 timers already,

4.

> there's not much waste currently, and we have plenty
> of padding.  I suppose we an always add a 'other_devices' thing later,
> so I prefer just sticking with this one for now.

Yeah, it's not a big deal either way.

thanks
-- PMM