Re: [PATCH v15 01/11] s390x/cpu topology: adding s390 specificities to CPU topology

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

On Wed, 2023-02-01 at 14:20 +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 | 24 +++++++++++++++++
>  target/s390x/cpu.h              |  5 ++++
>  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              |  7 +++++
>  qemu-options.hx                 |  7 +++--
>  10 files changed, 115 insertions(+), 12 deletions(-)
>  create mode 100644 include/hw/s390x/cpu-topology.h
> 
[...]
> 
> diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
> new file mode 100644
> index 0000000000..7a84b30a21
> --- /dev/null
> +++ b/include/hw/s390x/cpu-topology.h
> @@ -0,0 +1,24 @@
> +/*
> + * CPU Topology
> + *
> + * Copyright IBM Corp. 2022
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or (at
> + * your option) any later version. See the COPYING file in the top-level
> + * directory.
> + */
> +#ifndef HW_S390X_CPU_TOPOLOGY_H
> +#define HW_S390X_CPU_TOPOLOGY_H
> +
> +#define S390_TOPOLOGY_CPU_IFL   0x03
> +
> +enum s390_topology_polarity {
> +    POLARITY_HORIZONTAL,
> +    POLARITY_VERTICAL,
> +    POLARITY_VERTICAL_LOW = 1,
> +    POLARITY_VERTICAL_MEDIUM,
> +    POLARITY_VERTICAL_HIGH,
> +    POLARITY_MAX,
> +};

IMO you should define the polarization and entitlement enums as
qapi enums.
The polarization is passed as data in the qapi event when the polarization
changes.
And the entitlement is passed to qemu when modifying the topology.


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