Re: [PATCH v4 03/15] xen/x86: introduce new sub-hypercall to propagate CPPC data

[Jan Beulich <jbeulich@xxxxxxxx>]

On 16.05.2025 12:35, Penny, Zheng wrote:
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@xxxxxxxx>
>> Sent: Monday, April 28, 2025 11:57 PM
>>
>> On 14.04.2025 09:40, Penny Zheng wrote:
>>> @@ -459,6 +464,26 @@ struct xen_processor_performance {  typedef
>>> struct xen_processor_performance xen_processor_performance_t;
>>> DEFINE_XEN_GUEST_HANDLE(xen_processor_performance_t);
>>>
>>> +struct xen_processor_cppc {
>>> +    uint8_t flags; /* flag for CPPC sub info type */
>>> +    /*
>>> +     * Subset _CPC fields useful for CPPC-compatible cpufreq
>>> +     * driver's initialization
>>> +     */
>>> +    struct {
>>> +        uint32_t highest_perf;
>>> +        uint32_t nominal_perf;
>>> +        uint32_t lowest_nonlinear_perf;
>>> +        uint32_t lowest_perf;
>>> +        uint32_t lowest_mhz;
>>> +        uint32_t nominal_mhz;
>>> +    } cpc;
>>> +    struct xen_psd_package domain_info; /* _PSD */
>>
>> This being a member of the new type, ...
>>
>>> --- a/xen/include/xlat.lst
>>> +++ b/xen/include/xlat.lst
>>> @@ -168,6 +168,7 @@
>>>  !  processor_performance           platform.h
>>>  !  processor_power                 platform.h
>>>  ?  processor_px                    platform.h
>>> +?  processor_cppc                  platform.h
>>
>> ... how can it be ? here when it's ...
>>
>>>  !  psd_package                     platform.h
>>
>> ... ! here? And with it being ?, you're lacking a place where you invoke the 
>> resulting
>> checking macro (which I assume would cause a build failure).

I guess this wasn't clear enough then: Aiui you cannot "check" these, because 
the
native and compat ones are going to be different. You'll need to use ! here, and
then use the respective XLAT_* macro(s). IOW ...

> Understood, I see it automatically generates CHECK_psd_package. I shall 
> change psd_package with ? too
> In order to avoid causing build failure, I add "typedef struct 
> xen_psd_package xen_psd_package_t;"
> I'm not familiar with the compat framework, if it isn't the right way to fix, 
> plz let me know

... I expect this isn't the correct way of dealing with it.

Jan