Re: [PATCH RFC V2 10/37] arm/acpi: Enable ACPI support for vcpu hotplug

[Gavin Shan <gshan@redhat.com>]

Hi Salil,

On 9/26/23 20:04, Salil Mehta wrote:
> ACPI is required to interface QEMU with the guest. Roughly falls into below
> cases,
> 
> 1. Convey the possible vcpus config at the machine init time to the guest
>     using various DSDT tables like MADT etc.
> 2. Convey vcpu hotplug events to guest(using GED)
> 3. Assist in evaluation of various ACPI methods(like _EVT, _STA, _OST, _EJ0,
>     _MAT etc.)
> 4. Provides ACPI cpu hotplug state and 12 Byte memory mapped cpu hotplug
>     control register interface to the OSPM/guest corresponding to each possible
>     vcpu. The register interface consists of various R/W fields and their
>     handling operations. These are called when ever register fields or memory
>     regions are accessed(i.e. read or written) by OSPM when ever it evaluates
>     various ACPI methods.
> 
> Note: lot of this framework code is inherited from the changes already done for
>        x86 but still some minor changes are required to make it compatible with
>        ARM64.)
> 
> This patch enables the ACPI support for virtual cpu hotplug. ACPI changes
> required will follow in subsequent patches.
> 
> Co-developed-by: Salil Mehta <salil.mehta@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> ---
>   hw/arm/Kconfig | 1 +
>   1 file changed, 1 insertion(+)
> 

I assume this patch needs to be moved around to last one, until vCPU hotplug
is supported in the code base.

> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
> index 7e68348440..dae06158cd 100644
> --- a/hw/arm/Kconfig
> +++ b/hw/arm/Kconfig
> @@ -29,6 +29,7 @@ config ARM_VIRT
>       select ACPI_HW_REDUCED
>       select ACPI_APEI
>       select ACPI_VIOT
> +    select ACPI_CPU_HOTPLUG
>       select VIRTIO_MEM_SUPPORTED
>       select ACPI_CXL
>       select ACPI_HMAT

Thanks,
Gavin