Re: [PATCH RFC V3 11/29] arm/virt: Create GED dev before *disabled* CPU Objs are destroyed

[Gavin Shan <gshan@redhat.com>]

On 6/14/24 9:36 AM, Salil Mehta wrote:
> ACPI CPU hotplug state (is_present=_STA.PRESENT, is_enabled=_STA.ENABLED) for
> all the possible vCPUs MUST be initialized during machine init. This is done
> during the creation of the GED device. VMM/Qemu MUST expose/fake the ACPI state
> of the disabled vCPUs to the Guest kernel as 'present' (_STA.PRESENT) always
> i.e. ACPI persistent. if the 'disabled' vCPU objectes are destroyed before the
> GED device has been created then their ACPI hotplug state might not get
> initialized correctly as acpi_persistent flag is part of the CPUState. This will
> expose wrong status of the unplugged vCPUs to the Guest kernel.
> 
> Hence, moving the GED device creation before disabled vCPU objects get destroyed
> as part of the post CPU init routine.
> 
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> ---
>   hw/arm/virt.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 918bcb9a1b..5f98162587 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2467,6 +2467,12 @@ static void machvirt_init(MachineState *machine)
>   
>       create_gic(vms, sysmem);
>   
> +    has_ged = has_ged && aarch64 && firmware_loaded &&
> +              virt_is_acpi_enabled(vms);
> +    if (has_ged) {
> +        vms->acpi_dev = create_acpi_ged(vms);
> +    }
> +
>       virt_cpu_post_init(vms, sysmem);
>   
>       fdt_add_pmu_nodes(vms);
> @@ -2489,9 +2495,7 @@ static void machvirt_init(MachineState *machine)
>   
>       create_pcie(vms);
>   
> -    if (has_ged && aarch64 && firmware_loaded && virt_is_acpi_enabled(vms)) {
> -        vms->acpi_dev = create_acpi_ged(vms);
> -    } else {
> +    if (!has_ged) {
>           create_gpio_devices(vms, VIRT_GPIO, sysmem);
>       }
>   

It's likely the GPIO device can be created before those disabled CPU objects
are destroyed. It means the whole chunk of code can be moved together, I think.

Thanks,
Gavin