Re: [PATCH v2 3/9] hw/misc/iotkit-sysctl.c: add SSE-310 support

On Wed, 5 Aug 2026 at 16:30, Simon Xu <[email protected]> wrote:
>
> Add SSE-310 case statements for reads and writes.
> Add new SSE-310 PIDR and CLIDR values.
> Add new SSE-310 PPUINTSTAT register as RAZ with LOG_UMIMP on reads and
> RO on writes.
>
> Reviewed-by: Owen Giles <[email protected]>
> Reviewed-by: Robert Elliott <[email protected]>
> Signed-off-by: Simon Xu <[email protected]>
> ---
> v1 -> v2
>         Add PPUINTSTAT register
>         Make sure comments don't separate case statements

>  static const VMStateDescription iotkit_sysctl_sse300_vmstate = {
> diff --git a/include/hw/misc/iotkit-sysctl.h b/include/hw/misc/iotkit-sysctl.h
> index ce72258a84..8e1cf0012d 100644
> --- a/include/hw/misc/iotkit-sysctl.h
> +++ b/include/hw/misc/iotkit-sysctl.h
> @@ -53,6 +53,7 @@ struct IoTKitSysCtl {
>      uint32_t initsvtor1;
>      uint32_t nmi_enable;
>      uint32_t ewctrl;
> +    uint32_t ppuintstat;
>      uint32_t pwrctrl;
>      uint32_t pdcm_pd_sys_sense;
>      uint32_t pdcm_pd_sram0_sense;

If we add a new field to the state struct here, we need to
add it to the vmstate data structures for migration. That
means a new subsection with an sse310_needed() function
so we migrate the field for SSE310 only.

But since this field is only ever zero because the register
is read-only, I think it's simpler to just have "r = 0;" in the
register-read codepath, and drop the field entirely. If anybody
ever needs to implement the register to have real functionality
they can add whatever fields/migration handling they need for it
then; we don't need to try to guess now what that will be.

thanks
-- PMM