Re: [PATCH v15 03/11] target/s390x/cpu topology: handle STSI(15) and build the SYSIB

[Nina Schoetterl-Glausch]

On Wed, 2023-02-01 at 14:20 +0100, Pierre Morel wrote:
> On interception of STSI(15.1.x) the System Information Block
> (SYSIB) is built from the list of pre-ordered topology entries.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  include/hw/s390x/cpu-topology.h |  22 +++
>  include/hw/s390x/sclp.h         |   1 +
>  target/s390x/cpu.h              |  72 +++++++
>  hw/s390x/cpu-topology.c         |  10 +
>  target/s390x/kvm/cpu_topology.c | 335 ++++++++++++++++++++++++++++++++
>  target/s390x/kvm/kvm.c          |   5 +-
>  target/s390x/kvm/meson.build    |   3 +-
>  7 files changed, 446 insertions(+), 2 deletions(-)
>  create mode 100644 target/s390x/kvm/cpu_topology.c
> 
[...]
> +
> +/**
> + * s390_topology_from_cpu:
> + * @cpu: The S390CPU
> + *
> + * Initialize the topology id from the CPU environment.
> + */
> +static s390_topology_id s390_topology_from_cpu(S390CPU *cpu)
> +{
> +    s390_topology_id topology_id = {0};
> +
> +    topology_id.drawer = cpu->env.drawer_id;
> +    topology_id.book = cpu->env.book_id;
> +    topology_id.socket = cpu->env.socket_id;
> +    topology_id.origin = cpu->env.core_id / 64;
> +    topology_id.type = S390_TOPOLOGY_CPU_IFL;
> +    topology_id.dedicated = cpu->env.dedicated;
> +
> +    if (s390_topology.polarity == POLARITY_VERTICAL) {
> +        /*
> +         * Vertical polarity with dedicated CPU implies
> +         * vertical high entitlement.
> +         */
> +        if (topology_id.dedicated) {
> +            topology_id.polarity |= POLARITY_VERTICAL_HIGH;
> +        } else {
> +            topology_id.polarity |= cpu->env.entitlement;
> +        }

Why |= instead of an assignment?
Anyway, I think you can get rid of this in the next version.
If you define the entitlement via qapi you can just put a little switch
here and convert it to the hardware definition of polarization.
(Or you just do +1, but I think the switch is easier to understand)

> +    }
> +
> +    return topology_id;
> +}
> +
[...]