Re: [Qemu-devel] [PATCH] Basic support for ARM A15 "architectured" (cp15) timers

[Peter Maydell]

On 15 September 2012 17:41, Blue Swirl <address@hidden> wrote:
> On Sat, Sep 15, 2012 at 8:57 AM, Daniel Forsgren
> <address@hidden> wrote:
>> 1) What is considered to be part of the "core" and what is
>> considered to be a device external to the core? To me, it looks
>> like co-processor functionality in general is considered to be
>> part of the core (implemented in target-arm/helper.c or similar),
>> whereas timer devices in general are kept in hw/arm_* (c.f.
>> arm_timer.c and arm_mptimer.c). But in this case I have a timer
>> that is implemented as a coprocessor - where should that go? Or
>> should it be split in two places?
>
> SoC devices attached to the CPU is a bit grey area. In this case, I
> think coprocessor should be part of the CPU. Peter?

Yes, I think I would agree; as you say it's an odd case, but
I would go for putting it in the CPU model. (For KVM the
architectural timers are entirely handled in the kernel
so it's not possible to have an in-kernel CPU model and
out-of-kernel timers. I think that kind of weights towards
calling this part of the CPU.)

-- PMM