Re: [PATCH v8 03/12] s390x/cpu_topology: implementating Store Topology System Information

[Janosch Frank <frankja@linux.ibm.com>]

On 6/20/22 16:03, Pierre Morel wrote:

s390x/cpu_topology: Add STSI function code 15 handling

> The handling of STSI is enhanced with the interception of the
> function code 15 for storing CPU topology.

s/interception/handling/

> 
> Using the objects built during the plugging of CPU, we build the
> SYSIB 15_1_x structures.
> 
> With this patch the maximum MNEST level is 2, this is also
> the only level allowed and only SYSIB 15_1_2 will be built.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>

> +void insert_stsi_15_1_x(S390CPU *cpu, int sel2, __u64 addr, uint8_t ar)
> +{
> +    const MachineState *machine = MACHINE(qdev_get_machine());
> +    void *p;
> +    int ret;
> +
> +    /*
> +     * Until the SCLP STSI Facility reporting the MNEST value is used,
> +     * a sel2 value of 2 is the only value allowed in STSI 15.1.x.
> +     */
> +    if (sel2 != 2) {
> +        setcc(cpu, 3);
> +        return;
> +    }
> +
> +    p = g_malloc0(TARGET_PAGE_SIZE);
> +
> +    setup_stsi(machine, p, 2);
> +
> +    if (s390_is_pv()) {
> +        ret = s390_cpu_pv_mem_write(cpu, 0, p, TARGET_PAGE_SIZE);
> +    } else {
> +        ret = s390_cpu_virt_mem_write(cpu, addr, ar, p, TARGET_PAGE_SIZE);
> +    }

For later reference:
FCs over 3 are rejected by SIE for PV guests via cc 3.

I currently don't know if and when that will be changed but I'll ask around.

> +
> +    setcc(cpu, ret ? 3 : 0);
> +    g_free(p);
> +}
> +
> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
> index 7bd8db0e7b..563bf5ac60 100644
> --- a/target/s390x/kvm/kvm.c
> +++ b/target/s390x/kvm/kvm.c
> @@ -51,6 +51,7 @@
>   #include "hw/s390x/s390-virtio-ccw.h"
>   #include "hw/s390x/s390-virtio-hcall.h"
>   #include "hw/s390x/pv.h"
> +#include "hw/s390x/cpu-topology.h"
>   
>   #ifndef DEBUG_KVM
>   #define DEBUG_KVM  0
> @@ -1918,6 +1919,10 @@ static int handle_stsi(S390CPU *cpu)
>           /* Only sysib 3.2.2 needs post-handling for now. */
>           insert_stsi_3_2_2(cpu, run->s390_stsi.addr, run->s390_stsi.ar);
>           return 0;
> +    case 15:
> +        insert_stsi_15_1_x(cpu, run->s390_stsi.sel2, run->s390_stsi.addr,
> +                           run->s390_stsi.ar);
> +        return 0;
>       default:
>           return 0;
>       }
> diff --git a/target/s390x/meson.build b/target/s390x/meson.build
> index 84c1402a6a..890ccfa789 100644
> --- a/target/s390x/meson.build
> +++ b/target/s390x/meson.build
> @@ -29,6 +29,7 @@ s390x_softmmu_ss.add(files(
>     'sigp.c',
>     'cpu-sysemu.c',
>     'cpu_models_sysemu.c',
> +  'cpu_topology.c',
>   ))
>   
>   s390x_user_ss = ss.source_set()