Re: [PATCH for-7.1] hw/mips/malta: turn off x86 specific features of PIIX4_PM

[Ani Sinha]

On Thu, 28 Jul 2022, Peter Maydell wrote:

> On Thu, 28 Jul 2022 at 15:44, Dr. David Alan Gilbert
> <dgilbert@redhat.com> wrote:

> > Isn't the problem partially due to a 'stub' vmsd which isn't terminated?
>
> Yes, but setting these properties causes that vmsd
> (vmstate_acpi_pcihp_pci_status) to not be used:
>
>  * it is used only in VMSTATE_PCI_HOTPLUG()
>  * that macro is used only in hw/acpi/ich9.c (not relevant here) and
>    hw/acpi/piix4.c
>  * in piix4.c it is invoked passing it the test functions
>    vmstate_test_use_acpi_hotplug_bridge and
>    vmstate_test_migrate_acpi_index
>  * setting the properties on the device as this patch does
>    causes those test functions to return false, so the
>    vmstate_acpi_pcihp_pci_status is never examined

I believe this happens in vmstate_save_state_v() in this condition
checking:

  while (field->name) {
        if ((field->field_exists &&
             field->field_exists(opaque, version_id)) ||
            (!field->field_exists &&
             field->version_id <= version_id)) {