Re: [Qemu-devel] [PATCH v2 5/9] hw/block/pflash_cfi01: Add the DeviceReset() handler

[John Snow]

On 7/2/19 5:23 AM, Peter Maydell wrote:
> On Tue, 2 Jul 2019 at 04:16, John Snow <js...@redhat.com> wrote:
>> Does reset always get called as part of realize, really?
>>
>> Or are we just trusting that the device is probably going to get reset
>> by the guest during bringup?
> 
> Reset is not called "as part of realize", but it is guaranteed
> to be called after realize and before we try to run the guest,
> as long as the device is in the qbus tree. Things are in the
> qbus tree if either:
>  * they're plugged into something already in the tree (eg
>    pci devices, scsi disks)
>  * they're a sysbus device (which is automatically plugged into
>    the 'main system bus' which is effectively the root of the
>    qbus tree)
> 
> In this case TYPE_PFLASH_CFI01 is a subclass of TYPE_SYS_BUS_DEVICE,
> so it will always be reset as part of system reset.
> 
> (the main things which don't get automatically reset are direct
> subclasses of TYPE_DEVICE, notably CPU objects.)
> 
> thanks
> -- PMM
> 

Thank you for the lesson, that makes sense -- I saw the hotplug clause,
but missed the sysbus routine. Thanks to Laszlo for pointing this out in
great detail, too.

Phil, a clarified commit message is perfectly sufficient, and please
take my RB.