Re: [Qemu-devel] [PATCH v4 05/10] qom/cpu: move register_vmstate to common CPUClass.realizefn

[Eduardo Habkost]

On Fri, Feb 13, 2015 at 06:25:28PM +0800, Zhu Guihua wrote:
> From: Gu Zheng <address@hidden>
> 
> Move cpu vmstate register from cpu_exec_init into cpu_common_realizefn,
> and use cc->get_arch_id as the instance id that suggested by Igor to
> fix the migration issue.

If you are implementing something new, please do that in a separate patch,
either before or after moving the code. Makes it easier to review and easier to
revert in case something goes wrong.

See two additional issues below:

> 
> Signed-off-by: Gu Zheng <address@hidden>
> Signed-off-by: Zhu Guihua <address@hidden>
> ---
>  exec.c            | 25 ++++++++++++++++++-------
>  include/qom/cpu.h |  2 ++
>  qom/cpu.c         |  4 ++++
>  3 files changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/exec.c b/exec.c
> index 6dff7bc..8361591 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -513,10 +513,26 @@ void tcg_cpu_address_space_init(CPUState *cpu, 
> AddressSpace *as)
>  }
>  #endif
>  
> +void cpu_vmstate_register(CPUState *cpu)
> +{
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
> +    int cpu_index = cc->get_arch_id(cpu) + max_cpus;


Breaks linux-user build:

  LINK  x86_64-linux-user/qemu-x86_64
exec.o: In function `cpu_vmstate_register':
/home/ehabkost/rh/proj/virt/qemu/exec.c:533: undefined reference to `max_cpus'
collect2: error: ld returned 1 exit status
Makefile:182: recipe for target 'qemu-x86_64' failed
make[1]: *** [qemu-x86_64] Error 1
Makefile:169: recipe for target 'subdir-x86_64-linux-user' failed
make: *** [subdir-x86_64-linux-user] Error 2


> +    int compat_index = cc->get_compat_arch_id(cpu);
> +
> +    if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> +        vmstate_register_with_alias_id(NULL, cpu_index, &vmstate_cpu_common,
> +                                       cpu, compat_index, 3);
> +    }
> +
> +    if (cc->vmsd != NULL) {
> +        vmstate_register_with_alias_id(NULL, cpu_index, cc->vmsd,
> +                                       cpu, compat_index, 3);
> +    }
> +}
> +
>  void cpu_exec_init(CPUArchState *env)
>  {
>      CPUState *cpu = ENV_GET_CPU(env);
> -    CPUClass *cc = CPU_GET_CLASS(cpu);
>      CPUState *some_cpu;
>      int cpu_index;
>  
> @@ -539,18 +555,13 @@ void cpu_exec_init(CPUArchState *env)
>  #if defined(CONFIG_USER_ONLY)
>      cpu_list_unlock();
>  #endif
> -    if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> -        vmstate_register(NULL, cpu_index, &vmstate_cpu_common, cpu);
> -    }
>  #if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
>      register_savevm(NULL, "cpu", cpu_index, CPU_SAVE_VERSION,
>                      cpu_save, cpu_load, env);
>      assert(cc->vmsd == NULL);
>      assert(qdev_get_vmsd(DEVICE(cpu)) == NULL);
>  #endif
> -    if (cc->vmsd != NULL) {
> -        vmstate_register(NULL, cpu_index, cc->vmsd, cpu);
> -    }
>  }
>  
>  #if defined(CONFIG_USER_ONLY)
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index 2e68dd2..d0a50e2 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -565,6 +565,8 @@ void cpu_interrupt(CPUState *cpu, int mask);
>  
>  #endif /* USER_ONLY */
>  
> +void cpu_vmstate_register(CPUState *cpu);
> +
>  #ifdef CONFIG_SOFTMMU
>  static inline void cpu_unassigned_access(CPUState *cpu, hwaddr addr,
>                                           bool is_write, bool is_exec,
> diff --git a/qom/cpu.c b/qom/cpu.c
> index 83d7766..8e37045 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -302,6 +302,10 @@ static void cpu_common_realizefn(DeviceState *dev, Error 
> **errp)
>  {
>      CPUState *cpu = CPU(dev);
>  
> +#if !defined(CONFIG_USER_ONLY)
> +    cpu_vmstate_register(cpu);
> +#endif

CONFIG_USER_ONLY is never set on qom/cpu.c because it is target-independent
code.

Good news is that we already have vmstate stubs, so you shouldn't need any
CONFIG_USER_ONLY ifdefs around the vmstate code (but it looks like we will need
a max_cpus stub).

> +
>      if (dev->hotplugged) {
>          cpu_synchronize_post_init(cpu);
>          cpu_resume(cpu);
> -- 
> 1.9.3
> 
> 

-- 
Eduardo