Re: [PATCH RFC V2 22/37] hw/acpi: Make _MAT method optional

[Gavin Shan]

On 9/26/23 20:04, Salil Mehta wrote:
> From: Jean-Philippe Brucker <jean-philippe@linaro.org>
>
> The GICC interface on arm64 vCPUs is statically defined in the MADT, and
> doesn't require a _MAT entry. Although the GICC is indicated as present
> by the MADT entry, it can only be used from vCPU sysregs, which aren't
> accessible until hot-add.
>
> Co-developed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Co-developed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> ---
>   hw/acpi/cpu.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)

With following nits addressed:

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
> index e1299696d3..217db99538 100644
> --- a/hw/acpi/cpu.c
> +++ b/hw/acpi/cpu.c
> @@ -715,11 +715,13 @@ void build_cpus_aml(Aml *table, MachineState *machine, 
> CPUHotplugFeatures opts,
>               aml_append(dev, method);
>   
>               /* build _MAT object */
> -            assert(adevc && adevc->madt_cpu);
> -            adevc->madt_cpu(i, arch_ids, madt_buf,
> -                            true); /* set enabled flag */
> -            aml_append(dev, aml_name_decl("_MAT",
> -                aml_buffer(madt_buf->len, (uint8_t *)madt_buf->data)));
> +            if (adevc && adevc->madt_cpu) {
> +                assert(adevc && adevc->madt_cpu);
> +                adevc->madt_cpu(i, arch_ids, madt_buf,
> +                                true); /* set enabled flag */
> +                aml_append(dev, aml_name_decl("_MAT",
> +                    aml_buffer(madt_buf->len, (uint8_t *)madt_buf->data)));
> +            }
>               g_array_free(madt_buf, true);
>   
>               if (CPU(arch_ids->cpus[i].cpu) != first_cpu) {

May be worthy to have comment to mention _MAT isn't needed on aarch64.

               /* Build _MAT object, which isn't needed by aarch64 */

Thanks,
Gavin