Re: [PATCH v7 04/13] s390x: topology: implementating Store Topology System Information

[Thomas Huth <thuth@redhat.com>]

On 20/04/2022 13.57, Pierre Morel wrote:
> The handling of STSI is enhanced with the interception of the
> function code 15 for storing CPU topology.
> 
> Using the objects built during the pluging of CPU, we build the

s/pluging/plugging/

> 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>
> ---
...
> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> index f6969b76c5..a617c943ff 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -889,4 +889,5 @@ S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
>   
>   #include "exec/cpu-all.h"
>   
> +void insert_stsi_15_1_x(S390CPU *cpu, int sel2, __u64 addr, uint8_t ar);
>   #endif

Please keep an empty line before the #endif

> diff --git a/target/s390x/cpu_topology.c b/target/s390x/cpu_topology.c
> new file mode 100644
> index 0000000000..7f6db18829
> --- /dev/null
> +++ b/target/s390x/cpu_topology.c
> @@ -0,0 +1,112 @@
> +/*
> + * QEMU S390x CPU Topology
> + *
> + * Copyright IBM Corp. 2021

2022 ?

> + * Author(s): Pierre Morel <pmorel@linux.ibm.com>
> + *
> + * 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.
> + */
...
> +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, cc;
> +
> +    /*
> +     * 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);
> +    }
> +    cc = ret ? 3 : 0;
> +    setcc(cpu, cc);

Just a matter of taste (i.e. keep it if you like) - but you could scratch 
the cc variable in this function by just doing:

     setcc(cpu, ret ? 3 : 0);

> +    g_free(p);
> +}
> +

  Thomas