Re: [Xen-devel] [RFC PATCH 03/31] pmstat: move pmstat.c file to the xen/drivers/pm/stat.c location

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 18.05.18 at 16:13, <olekstysh@xxxxxxxxx> wrote:
> Hi,
> 
> On Fri, May 18, 2018 at 2:35 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>>> On 18.05.18 at 13:14, <olekstysh@xxxxxxxxx> wrote:
>>> On Mon, May 7, 2018 at 6:36 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>>>>> On 09.11.17 at 18:09, <olekstysh@xxxxxxxxx> wrote:
>>>>> +int acpi_set_pdc_bits(u32 acpi_id, XEN_GUEST_HANDLE_PARAM(uint32) pdc)
>>>>> +{
>>>>> +    u32 bits[3];
>>>>> +    int ret;
>>>>> +
>>>>> +    if ( copy_from_guest(bits, pdc, 2) )
>>>>> +        ret = -EFAULT;
>>>>> +    else if ( bits[0] != ACPI_PDC_REVISION_ID || !bits[1] )
>>>>> +        ret = -EINVAL;
>>>>> +    else if ( copy_from_guest_offset(bits + 2, pdc, 2, 1) )
>>>>> +        ret = -EFAULT;
>>>>> +    else
>>>>> +    {
>>>>> +        u32 mask = 0;
>>>>> +
>>>>> +        if ( xen_processor_pmbits & XEN_PROCESSOR_PM_CX )
>>>>> +            mask |= ACPI_PDC_C_MASK | ACPI_PDC_SMP_C1PT;
>>>>> +        if ( xen_processor_pmbits & XEN_PROCESSOR_PM_PX )
>>>>> +            mask |= ACPI_PDC_P_MASK | ACPI_PDC_SMP_C1PT;
>>>>> +        if ( xen_processor_pmbits & XEN_PROCESSOR_PM_TX )
>>>>> +            mask |= ACPI_PDC_T_MASK | ACPI_PDC_SMP_C1PT;
>>>>> +        bits[2] &= (ACPI_PDC_C_MASK | ACPI_PDC_P_MASK | ACPI_PDC_T_MASK |
>>>>> +                    ACPI_PDC_SMP_C1PT) & ~mask;
>>>>> +        ret = arch_acpi_set_pdc_bits(acpi_id, bits, mask);
>>>>> +    }
>>>>> +    if ( !ret && __copy_to_guest_offset(pdc, 2, bits + 2, 1) )
>>>>> +        ret = -EFAULT;
>>>>> +
>>>>> +    return ret;
>>>>> +}
>>>>
>>>> Looks quite ACPI-specific.
>>> Yes, current patch does just a movement.
>>>
>>> Next patch [1] wraps it in #ifdef CONFIG_ACPI.
>>>
>>> However during patch discussion we decided to move this function to 
>>> arch/x86.
>>> It is called from arch/x86/platform_hypercall.c and pulls a bunch of
>>> #define-s from pdc_intel.h
>>
>> Not sure - the function may be used by x86 only right now, but is what it
>> does really x86-specific?
> 
> I am not familiar with ACPI to answer precisely.
> What I see here is that these are named "Intel Processor Driver
> Capabilities flags".
> 
> However, the Section 8.4.1 of document [1] doesn't explicitly say that
> "_PDC" is supposed to be x86 specific thing only.
> 
> [1] 
> http://www.uefi.org/sites/default/files/resources/ACPI%206_2_A_Sept29.pdf 
> 
> So, I can leave acpi_set_pdc_bits() in xen/drivers/pm/stat.c for now,
> but definitely wrapped into #ifdef CONFIG_ACPI.

Yes please, unless indications of it being x86 specific can be provided.

Jan



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