Re: [PATCH v20 01/21] s390x/cpu topology: add s390 specifics to CPU topology

["Cédric Le Goater" <clg@kaod.org>]

On 5/2/23 14:05, Cédric Le Goater wrote:
> On 4/25/23 18:14, Pierre Morel wrote:
>> S390 adds two new SMP levels, drawers and books to the CPU
>> topology.
>> The S390 CPU have specific topology features like dedication
>> and entitlement to give to the guest indications on the host
>> vCPUs scheduling and help the guest take the best decisions
>> on the scheduling of threads on the vCPUs.
>>
>> Let us provide the SMP properties with books and drawers levels
>> and S390 CPU with dedication and entitlement,
> 
> I think CpuS390Entitlement should be introduced in a separate patch and
> only under target/s390x/cpu.c. It is machine specific and doesn't belong
> to the machine common definitions.
> 
> 'books' and 'drawers' could also be considered z-specific but High End
> POWER systems (16s) have similar topology concepts, at least for drawers :
> a group of 4 sockets. So let's keep it that way.
> 
> 
> This problably means you will have to rework the get/set property handlers
> with strcmp() or simply copy the generated lookup struct :
> 
> const QEnumLookup CpuS390Entitlement_lookup = {
>      .array = (const char *const[]) {
>          [S390_CPU_ENTITLEMENT_AUTO] = "auto",
>          [S390_CPU_ENTITLEMENT_LOW] = "low",
>          [S390_CPU_ENTITLEMENT_MEDIUM] = "medium",
>          [S390_CPU_ENTITLEMENT_HIGH] = "high",
>      },
>      .size = S390_CPU_ENTITLEMENT__MAX
> };
> 
> It should be fine.

The enum is required by the set-cpu-topology QMP command in patch 8.
Forget my comment, it would require too much changes in your series
to introduce CPU Entitlement independently.

C.