Re: [PATCH v4] hw/arm/smmuv3: Add GBPA register

[Mostafa Saleh <smostafa@google.com>]

On Sat, Feb 11, 2023 at 01:48:57PM -1000, Richard Henderson wrote:

> Just "return s->gbpa != SMMU_GBPA_RESET_VAL;".

I will update it.

> > @@ -1512,6 +1553,10 @@ static const VMStateDescription vmstate_smmuv3 = {
> >           VMSTATE_END_OF_LIST(),
> >       },
> > +    .subsections = (const VMStateDescription * []) {
> > +        &vmstate_gbpa,
> > +        NULL
> > +    }
> 
> Actually, I suspect that you need a pre_load hook that resets gbpa, which
> will then be overwritten if and only if the saved value != reset value.
> 

Please correct me if I am wrong. From what I see, the initial for value
GBPA will be set from smmu_reset_hold which is called from context of
qemu_system_reset from qemu_init context.
And migration will start after that in migration_incoming_process from
qemu_main_loop context.

I validated that also by printing the value of GBPA from vmstate_smmuv3
pre_load at migration without GPBA, and it is the same as
SMMU_GBPA_RESET_VAL.

Thanks,
Mostafa