Re: [Qemu-devel] [PATCH qom-cpu v3 4/9] cpu: Turn cpu_paging_enabled() into a CPUState hook

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 30 May 2013 17:07:56 +0200
Andreas Färber <afaerber@suse.de> wrote:

> Signed-off-by: Andreas Färber <afaerber@suse.de>

Nitpick alarm on.

> ---
>  include/qom/cpu.h                 | 10 ++++++++++
>  include/sysemu/memory_mapping.h   |  1 -
>  memory_mapping-stub.c             |  6 ------
>  memory_mapping.c                  |  2 +-
>  qom/cpu.c                         | 13 +++++++++++++
>  target-i386/arch_memory_mapping.c |  6 +-----
>  target-i386/cpu.c                 | 11 +++++++++--
>  7 files changed, 34 insertions(+), 15 deletions(-)
> 
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index 7cd9442..cf5fec2 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -48,6 +48,7 @@ typedef struct CPUState CPUState;
>   * @reset: Callback to reset the #CPUState to its initial state.
>   * @do_interrupt: Callback for interrupt handling.
>   * @get_arch_id: Callback for getting architecture-dependent CPU ID.
> + * @get_paging_enabled: Callback for inquiring whether paging is enabled.
>   * @vmsd: State description for migration.
>   *
>   * Represents a CPU family or model.
> @@ -62,6 +63,7 @@ typedef struct CPUClass {
>      void (*reset)(CPUState *cpu);
>      void (*do_interrupt)(CPUState *cpu);
>      int64_t (*get_arch_id)(CPUState *cpu);
> +    bool (*get_paging_enabled)(CPUState *cpu);

Argument could be const?

>  
>      const struct VMStateDescription *vmsd;
>      int (*write_elf64_note)(WriteCoreDumpFunction f, CPUState *cpu,
> @@ -138,6 +140,14 @@ struct CPUState {
>  };
>  
>  /**
> + * cpu_paging_enabled:
> + * @cpu: The CPU whose state is to be inspected.
> + *
> + * Returns: %true if paging is enabled, %false otherwise.
> + */
> +bool cpu_paging_enabled(CPUState *cpu);
> +
> +/**
>   * cpu_write_elf64_note:
>   * @f: pointer to a function that writes memory to a file
>   * @cpu: The CPU whose memory is to be dumped
> diff --git a/include/sysemu/memory_mapping.h b/include/sysemu/memory_mapping.h
> index 1256125..6f01524 100644
> --- a/include/sysemu/memory_mapping.h
> +++ b/include/sysemu/memory_mapping.h
> @@ -31,7 +31,6 @@ typedef struct MemoryMappingList {
>  } MemoryMappingList;
>  
>  int cpu_get_memory_mapping(MemoryMappingList *list, CPUArchState *env);
> -bool cpu_paging_enabled(CPUArchState *env);
>  
>  /*
>   * add or merge the memory region [phys_addr, phys_addr + length) into the
> diff --git a/memory_mapping-stub.c b/memory_mapping-stub.c
> index 24d5d67..6c0dfeb 100644
> --- a/memory_mapping-stub.c
> +++ b/memory_mapping-stub.c
> @@ -25,9 +25,3 @@ int cpu_get_memory_mapping(MemoryMappingList *list,
>  {
>      return -1;
>  }
> -
> -bool cpu_paging_enabled(CPUArchState *env)
> -{
> -    return true;
> -}
> -
> diff --git a/memory_mapping.c b/memory_mapping.c
> index ff45b3a..0790aac 100644
> --- a/memory_mapping.c
> +++ b/memory_mapping.c
> @@ -170,7 +170,7 @@ static CPUArchState *find_paging_enabled_cpu(CPUArchState *start_cpu)
>      CPUArchState *env;
>  
>      for (env = start_cpu; env != NULL; env = env->next_cpu) {
> -        if (cpu_paging_enabled(env)) {
> +        if (cpu_paging_enabled(ENV_GET_CPU(env))) {
>              return env;
>          }
>      }
> diff --git a/qom/cpu.c b/qom/cpu.c
> index 04aefbb..ea7e676 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -50,6 +50,18 @@ bool cpu_exists(int64_t id)
>      return data.found;
>  }
>  
> +bool cpu_paging_enabled(CPUState *cpu)
> +{
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
> +
> +    return cc->get_paging_enabled(cpu);
> +}
> +
> +static bool cpu_common_get_paging_enabled(CPUState *cpu)
> +{
> +    return true;
> +}

Not sure if this is important, but I wonder if we want to do this

I mean, for all cases where you want to know if paging is enabled, what
will happen if this default method says "yes, it's enabled" but it
actually isn't?

> +
>  /* CPU hot-plug notifiers */
>  static NotifierList cpu_added_notifiers =
>      NOTIFIER_LIST_INITIALIZER(cpu_add_notifiers);
> @@ -176,6 +188,7 @@ static void cpu_class_init(ObjectClass *klass, void *data)
>      k->class_by_name = cpu_common_class_by_name;
>      k->reset = cpu_common_reset;
>      k->get_arch_id = cpu_common_get_arch_id;
> +    k->get_paging_enabled = cpu_common_get_paging_enabled;
>      k->write_elf32_qemunote = cpu_common_write_elf32_qemunote;
>      k->write_elf32_note = cpu_common_write_elf32_note;
>      k->write_elf64_qemunote = cpu_common_write_elf64_qemunote;
> diff --git a/target-i386/arch_memory_mapping.c b/target-i386/arch_memory_mapping.c
> index 5096fbd..c5a10ec 100644
> --- a/target-i386/arch_memory_mapping.c
> +++ b/target-i386/arch_memory_mapping.c
> @@ -241,7 +241,7 @@ static void walk_pml4e(MemoryMappingList *list,
>  
>  int cpu_get_memory_mapping(MemoryMappingList *list, CPUArchState *env)
>  {
> -    if (!cpu_paging_enabled(env)) {
> +    if (!cpu_paging_enabled(ENV_GET_CPU(env))) {
>          /* paging is disabled */
>          return 0;
>      }
> @@ -273,7 +273,3 @@ int cpu_get_memory_mapping(MemoryMappingList *list, CPUArchState *env)
>      return 0;
>  }
>  
> -bool cpu_paging_enabled(CPUArchState *env)
> -{
> -    return env->cr[0] & CR0_PG_MASK;
> -}
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 1a501d9..7364e3b 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2505,6 +2505,13 @@ static int64_t x86_cpu_get_arch_id(CPUState *cs)
>      return env->cpuid_apic_id;
>  }
>  
> +static bool x86_cpu_get_paging_enabled(CPUState *cs)
> +{
> +    X86CPU *cpu = X86_CPU(cs);
> +
> +    return cpu->env.cr[0] & CR0_PG_MASK;
> +}
> +
>  static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
>  {
>      X86CPUClass *xcc = X86_CPU_CLASS(oc);
> @@ -2519,6 +2526,8 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
>      cc->reset = x86_cpu_reset;
>  
>      cc->do_interrupt = x86_cpu_do_interrupt;
> +    cc->get_arch_id = x86_cpu_get_arch_id;

Unrelated change?

> +    cc->get_paging_enabled = x86_cpu_get_paging_enabled;
>  #ifndef CONFIG_USER_ONLY
>      cc->write_elf64_note = x86_cpu_write_elf64_note;
>      cc->write_elf64_qemunote = x86_cpu_write_elf64_qemunote;
> @@ -2526,8 +2535,6 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
>      cc->write_elf32_qemunote = x86_cpu_write_elf32_qemunote;
>  #endif
>      cpu_class_set_vmsd(cc, &vmstate_x86_cpu);
> -
> -    cc->get_arch_id = x86_cpu_get_arch_id;
>  }
>  
>  static const TypeInfo x86_cpu_type_info = {