Re: [PATCH v14 01/11] s390x/cpu topology: adding s390 specificities to CPU topology

[Nina Schoetterl-Glausch <nsg@linux.ibm.com>]

On Thu, 2023-01-05 at 15:53 +0100, Pierre Morel wrote:
> S390 adds two new SMP levels, drawers and books to the CPU
> topology.
> The S390 CPU have specific toplogy features like dedication
> and polarity 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 polarity,
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  qapi/machine.json               | 14 ++++++++--
>  include/hw/boards.h             | 10 ++++++-
>  include/hw/s390x/cpu-topology.h | 23 ++++++++++++++++
>  target/s390x/cpu.h              |  6 +++++
>  hw/core/machine-smp.c           | 48 ++++++++++++++++++++++++++++-----
>  hw/core/machine.c               |  4 +++
>  hw/s390x/s390-virtio-ccw.c      |  2 ++
>  softmmu/vl.c                    |  6 +++++
>  target/s390x/cpu.c              | 10 +++++++
>  qemu-options.hx                 |  6 +++--
>  10 files changed, 117 insertions(+), 12 deletions(-)
>  create mode 100644 include/hw/s390x/cpu-topology.h
> 
[...]

> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> index 7d6d01325b..39ea63a416 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -131,6 +131,12 @@ struct CPUArchState {
>  
>  #if !defined(CONFIG_USER_ONLY)
>      uint32_t core_id; /* PoP "CPU address", same as cpu_index */
> +    int32_t socket_id;
> +    int32_t book_id;
> +    int32_t drawer_id;
> +    int32_t dedicated;
> +    int32_t polarity;

If I understood the architecture correctly, the polarity is a property of the configuration,
not the cpus. So this should be vertical_entitlement, and there should be a machine (?) property
specifying if the polarity is horizontal or vertical.

> +    int32_t cpu_type;
>      uint64_t cpuid;
>  #endif
>  

[...]