Re: [RFC 04/13] rust: add bindings for gpio_{in|out} initialization

[Paolo Bonzini <pbonzini@redhat.com>]

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Il ven 17 gen 2025, 11:55 Zhao Liu <zhao1.liu@intel.com> ha scritto:

> > >         assert!(pins.len() > 0);
> >
> > !pins.is_empty().
>
> Yes.
>
> > But I am not sure it's needed...
> > >
> > >         unsafe {
> > >             qdev_init_gpio_out(
> > >                 self.upcast::<DeviceState>() as *const DeviceState as
> *mut DeviceState,
> > >                 pins[0].as_ptr(),
> > >                 pins.len() as c_int,
> >
> > ... if you use instead pins.as_ptr() without the initial dereference.
>
> Emm, pins.as_ptr() returns `*const InterruptSource`, which can't be
> converted to `*mut *mut IRQState` with InterruptSource::as_ptr().
>

It can be cast, since an InterruptSource is essentially a *mut IRQState,
but I agree it's not pretty.

Maybe add a "pub(crate) fn as_slice_of_qemu_irq(slice: [Self]) -> [*mut
IRQState)" to InterruptSource? It would just do a transmute and build the
new slice with from_raw_parts. And then "let pins =
InterruptSource::as_slice_of_qemu_irq(pins)" lets you use pins.as_ptr().

Paolo

So I haven't thought of a better way yet...
>
> > > impl HPETState {
> > >     ...
> > >
> > >     fn handle_legacy_irq(&self, irq: u32, level: u32) {
> > >         if irq == HPET_LEGACY_PIT_INT {
> > >             if !self.is_legacy_mode() {
> > >                 self.irqs[0].set(level != 0);
> > >             }
> > >         } else {
> > >             self.rtc_irq_level.set(level as u8);
> >
> > Any reason why you defined rtc_irq_level as InterruptSource<u8>
> > instead of InterruptSource<u32>?
>
> Thanks! I missed to clean up this, having previously used u8.
>
> Regards,
> Zhao
>
>

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