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

[Paolo Bonzini]

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()?

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

Paolo