Re: [PATCH v2 2/2] domain: expose newly introduced hypercalls as XENFEAT

[Henry Wang <Henry.Wang@xxxxxxx>]

Hi,

> On Oct 6, 2023, at 21:05, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> 
> On 06/10/2023 2:00 pm, Roger Pau Monne wrote:
>> diff --git a/xen/include/public/features.h b/xen/include/public/features.h
>> index d2a9175aae67..22713a51b520 100644
>> --- a/xen/include/public/features.h
>> +++ b/xen/include/public/features.h
>> @@ -111,6 +111,15 @@
>> #define XENFEAT_not_direct_mapped         16
>> #define XENFEAT_direct_mapped             17
>> 
>> +/*
>> + * Signal whether the domain is permitted to use the following hypercalls:
>> + *
>> + * VCPUOP_register_runstate_phys_area
>> + * VCPUOP_register_vcpu_time_phys_area
>> + */
>> +#define XENFEAT_runstate_phys_area  18
>> +#define XENFEAT_vcpu_time_phys_area  19
>> +
>> #define XENFEAT_NR_SUBMAPS 1
>> 
>> #endif /* __XEN_PUBLIC_FEATURES_H__ */
>> diff --git a/xen/include/public/vcpu.h b/xen/include/public/vcpu.h
>> index 8fb0bd1b6c03..03b031a3e557 100644
>> --- a/xen/include/public/vcpu.h
>> +++ b/xen/include/public/vcpu.h
>> @@ -236,6 +236,9 @@ 
>> DEFINE_XEN_GUEST_HANDLE(vcpu_register_time_memory_area_t);
>>  * Note that the area registered via VCPUOP_register_runstate_memory_area 
>> will
>>  * be updated in the same manner as the one registered via virtual address 
>> PLUS
>>  * VMASST_TYPE_runstate_update_flag engaged by the domain.
>> + *
>> + * XENFEAT_{runstate,vcpu_time}_phys_area feature bits signal if the domain 
>> is
>> + * permitted the usage of the hypercalls.
>>  */
>> #define VCPUOP_register_runstate_phys_area      14
>> #define VCPUOP_register_vcpu_time_phys_area     15
> 
> For both of these, I'd suggest s/permitted/able/.  For older versions of
> Xen which don't advertise the XENFEAT, it's a matter of capability, not
> permission.
> 
> Otherwise, Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> and
> I'm happy to adjust on commit to save sending out a v3.

Release-acked-by: Henry Wang <Henry.Wang@xxxxxxx>

Kind regards,
Henry

> 
> Thanks,
> 
> ~Andrew