[Xen-devel] Ping: [PATCH] xen/ACPI: don't upload Px/Cx data for disabled processors

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.06.18 at 12:17,  wrote:
> This is unnecessary and triggers a warning in the hypervisor.
> 
> Often systems have more processor entries in their ACPI tables than are
> actually installed/active. The ACPI_STA_DEVICE_PRESENT bit cannot be
> reliably used, but the ACPI_MADT_ENABLED bit can. In order to not
> introduce new functions in the main ACPI processor driver code, simply
> use acpi_get_phys_id(), which does more than we need, but which checks
> the MADT enabled bit in the process. Any CPU for which we can't
> determine the APIC ID is unlikely to work properly anyway, so the extra
> checks done by acpi_get_phys_id() should do no harm.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
>  drivers/acpi/processor_core.c    |    1 +
>  drivers/xen/xen-acpi-processor.c |    6 ++++++
>  2 files changed, 7 insertions(+)

With Jürgen's R-b in place, may I ask for an ack for the processor_core.c
change, or - in case you dislike the new export - an alternative suggestion?

Thanks, Jan

> --- 4.18-rc2/drivers/acpi/processor_core.c
> +++ 4.18-rc2-xen-ACPI-processor-skip-disabled/drivers/acpi/processor_core.c
> @@ -205,6 +205,7 @@ phys_cpuid_t acpi_get_phys_id(acpi_handl
>  
>       return phys_id;
>  }
> +EXPORT_SYMBOL_GPL(acpi_get_phys_id);
>  
>  int acpi_map_cpuid(phys_cpuid_t phys_id, u32 acpi_id)
>  {
> --- 4.18-rc2/drivers/xen/xen-acpi-processor.c
> +++ 
> 4.18-rc2-xen-ACPI-processor-skip-disabled/drivers/xen/xen-acpi-processor.c
> @@ -362,6 +362,12 @@ read_acpi_id(acpi_handle handle, u32 lvl
>       default:
>               return AE_OK;
>       }
> +     if (invalid_phys_cpuid(acpi_get_phys_id(handle,
> +                                             acpi_type == ACPI_TYPE_DEVICE,
> +                                             acpi_id))) {
> +             pr_debug("CPU with ACPI ID %u is unavailable\n", acpi_id);
> +             return AE_OK;
> +     }
>       /* There are more ACPI Processor objects than in x2APIC or MADT.
>        * This can happen with incorrect ACPI SSDT declerations. */
>       if (acpi_id >= nr_acpi_bits) {
> 
> 
> 
> 




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