Re: [RFC 09/13] i386/fw_cfg: move hpet_cfg definition to hpet.c

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 5/12/24 22:19, Paolo Bonzini wrote:
> On Thu, Dec 5, 2024 at 10:18 PM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
>>
>> On 5/12/24 13:46, Zhao Liu wrote:
>>> Hi Philippe,
>>>
>>> On Thu, Dec 05, 2024 at 01:04:58PM +0100, Philippe Mathieu-Daudé wrote:
>>>> Date: Thu, 5 Dec 2024 13:04:58 +0100
>>>> From: Philippe Mathieu-Daudé <philmd@linaro.org>
>>>> Subject: Re: [RFC 09/13] i386/fw_cfg: move hpet_cfg definition to hpet.c
>>>>
>>>> On 5/12/24 07:07, Zhao Liu wrote:
>>>>> HPET device needs to access and update hpet_cfg variable, but now it is
>>>>> defined in hw/i386/fw_cfg.c and Rust code can't access it.
>>>>>
>>>>> Move hpet_cfg definition to hpet.c (and rename it to hpet_fw_cfg). This
>>>>> allows Rust HPET device implements its own global hpet_fw_cfg variable,
>>>>> and will further reduce the use of unsafe C code access and calls in the
>>>>> Rust HPET implementation.
>>>>>
>>>>> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
>>>>> ---
>>>>>     hw/i386/fw_cfg.c        |  4 +---
>>>>>     hw/timer/hpet.c         | 16 +++++++++-------
>>>>>     include/hw/timer/hpet.h |  2 +-
>>>>>     3 files changed, 11 insertions(+), 11 deletions(-)
>>>>
>>>>
>>>>> diff --git a/include/hw/timer/hpet.h b/include/hw/timer/hpet.h
>>>>> index d17a8d43199e..dbf709251a8f 100644
>>>>> --- a/include/hw/timer/hpet.h
>>>>> +++ b/include/hw/timer/hpet.h
>>>>> @@ -74,7 +74,7 @@ struct hpet_fw_config
>>>>>         struct hpet_fw_entry hpet[8];
>>>>>     } QEMU_PACKED;
>>>>> -extern struct hpet_fw_config hpet_cfg;
>>>>> +extern struct hpet_fw_config hpet_fw_cfg;
>>>>
>>>> Could this field belong to the (yet unexisting) HPETClass?
>>>
>>> Several instances would share the same class, so HPETClass could manage
>>> multiple HPETState info.
>>>
>>> But in fw_cfg.c, do you have idea about how to get the HPETClass?
>>
>> Have hpet_find() return an Object and call object_get_class()?

Implemented as 
https://lore.kernel.org/qemu-devel/20241206191124.9195-1-philmd@linaro.org/, 
hoping it simplifies the Rust model integration.

> 
> That would work, but anyhow this patch breaks compilation without HPET
> so the question is a bit moot. :)
> 
> Paolo
>