Re: [Qemu-devel] [PATCH 4/6] hw/arm/boot: register cpu reset handlers if using -bios

[Andreas Färber]

Am 17.09.2014 um 18:47 schrieb Peter Maydell:
> On 17 September 2014 09:40, Andreas Färber <address@hidden> wrote:
>> We avoided that by not using DeviceClass::reset but CPUClass::reset.
>> It's a question of assuring appropriate reset ordering between CPU and
>> devices. PowerPC needed a special reset order via hook in (what is now)
>> MachineClass.
> 
>> So while I agree that CPU reset registration is not ideal and needs
>> changing, I am not convinced that we can generally make the change and
>> hope for the best. I wouldn't mind an incremental transition though,
>> with arm taking the first step - still leaves the question of exact
>> direction. If you look at x86, you will find that despite my protest
>> against this inconsistency, the reset hook registration was moved into
>> CPU code but none of the other targets changed alongside.
> 
> I don't object to taking a pragmatic approach in the ARM code
> (eg this patch). I just wanted to know if you had a preferred
> direction we should be taking instead (which as you say we
> kind of have to do in an incremental way). It sounds like you
> don't have anything concrete in mind so maybe we should just
> apply this patch.

Ack.

One other concern I have with this patch is the loop assuming that all
following CPUs will be of type ARMCPU, but I suspect there will be other
code making the same assumption - in that case Reviewed-by.

> In general I suspect there are a lot of unresolved issues in
> our handling of reset -- it's a complicated area which we
> attempt to address in an over-simplistic way at the moment :-(

Yes, having test cases for all machines would help refactor these things...

Andreas

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