Re: [PATCH] target/mips/cpu: Move initialization of memory region to realize function

[Markus Armbruster <armbru@redhat.com>]

Thomas Huth <thuth@redhat.com> writes:

> From: Thomas Huth <thuth@redhat.com>
>
> When introspecting the Loongson-3A4000 CPUs from the command line, QEMU
> currently crashes:
>
>  $ ./qemu-system-mips64el -device Loongson-3A4000-mips64-cpu,help
>  qemu-system-mips64el: ../../devel/qemu/system/physmem.c:1401:
>   register_multipage: Assertion `num_pages' failed.
>  Aborted (core dumped)
>
> Move the initialization of the memory regions to the realize function
> to fix this problem.
>
> Reported-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: Thomas Huth <thuth@redhat.com>

See also my ramblings in reply to the related xtensa patch:

    Subject: Re: [PATCH] target/xtensa/cpu: Move initialization of memory region to realize function
    Date: Thu, 12 Mar 2026 08:51:43 +0100
    Message-ID: <87y0jxzdrk.fsf@pond.sub.org>

> ---
>  target/mips/cpu.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/target/mips/cpu.c b/target/mips/cpu.c
> index e424d115018..5f88c077dbf 100644
> --- a/target/mips/cpu.c
> +++ b/target/mips/cpu.c
> @@ -460,6 +460,14 @@ static void mips_cpu_realizefn(DeviceState *dev, Error **errp)
>      MIPSCPUClass *mcc = MIPS_CPU_GET_CLASS(dev);
>      Error *local_err = NULL;
>  
> +#ifndef CONFIG_USER_ONLY
> +    if (mcc->cpu_def->lcsr_cpucfg2 & (1 << CPUCFG2_LCSRP)) {
> +        memory_region_init_io(&env->iocsr.mr, OBJECT(cpu), NULL,
> +                              env, "iocsr", UINT64_MAX);
> +        address_space_init(&env->iocsr.as, &env->iocsr.mr, "IOCSR");
> +    }
> +#endif
> +
>      if (!clock_get(cpu->clock)) {
>  #ifndef CONFIG_USER_ONLY
>          if (!qtest_enabled()) {
> @@ -504,14 +512,6 @@ static void mips_cpu_initfn(Object *obj)
>      cpu->count_div = clock_new(OBJECT(obj), "clk-div-count");
>      env->count_clock = clock_new(OBJECT(obj), "clk-count");
>      env->cpu_model = mcc->cpu_def;
> -#ifndef CONFIG_USER_ONLY
> -    if (mcc->cpu_def->lcsr_cpucfg2 & (1 << CPUCFG2_LCSRP)) {
> -        memory_region_init_io(&env->iocsr.mr, OBJECT(cpu), NULL,
> -                                env, "iocsr", UINT64_MAX);
> -        address_space_init(&env->iocsr.as,
> -                            &env->iocsr.mr, "IOCSR");
> -    }
> -#endif
>  }
>  
>  static char *mips_cpu_type_name(const char *cpu_model)

Tested-by: Markus Armbruster <armbru@redhat.com>