Re: [Qemu-devel] [PATCH 23/27] hw/core/or-irq: Support more than 16 inputs to an OR gate

[Paolo Bonzini]

On 30/05/2018 19:35, Peter Maydell wrote:
> On 30 May 2018 at 17:59, Paolo Bonzini <address@hidden> wrote:
>> On 21/05/2018 17:02, Peter Maydell wrote:
>>> On 21 May 2018 at 15:34, Paolo Bonzini <address@hidden> wrote:
>>>> Why do the levels have to be migrated at all?  It should be enough if
>>>> the IRQ level is either migrated manually, or restored (e.g. in
>>>> post_save callbacks) through other data that is migrated.
>>> This is standard behaviour for devices: they track their
>>> inbound irq/gpio lines, and then that becomes internal state for
>>> them that must be migrated.
>>
>> But or_irq's input are another device's outbound lines, so tracking them
>> should not be necessary.  The other device would do it for or_irq.
> 
> There's no mechanism in qemu_irq for the destination end to ask
> the source end about its current value. The information flow
> is strictly one-way.

On postload, the source must call qemu_set_irq and that will cause an
update of the or_irq, won't it?

Paolo