Re: [Qemu-devel] [RFC PATCH v4 02/11] exec: Do vmstate unregistration from cpu_exec_exit()

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Aug 06, 2015 at 10:57:08AM +0530, Bharata B Rao wrote:
> cpu_exec_init() does vmstate_register and register_savevm for the CPU device.
> These need to be undone from cpu_exec_exit(). These changes are needed to
> support CPU hot removal and also to correctly fail hotplug attempts
> beyond max_cpus.
> 
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>

As with 1/2, looks reasonable, but I'm wondering how x86 hotplug is
getting away without this.

> ---
>  exec.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/exec.c b/exec.c
> index b196d68..3415cd7 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -545,6 +545,8 @@ static int cpu_get_free_index(Error **errp)
>  
>  void cpu_exec_exit(CPUState *cpu)
>  {
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
> +
>      if (cpu->cpu_index == -1) {
>          /* cpu_index was never allocated by this @cpu or was already freed. */
>          return;
> @@ -556,6 +558,15 @@ void cpu_exec_exit(CPUState *cpu)
>      }
>      bitmap_clear(cpu_index_map, cpu->cpu_index, 1);
>      cpu->cpu_index = -1;
> +    if (cc->vmsd != NULL) {
> +        vmstate_unregister(NULL, cc->vmsd, cpu);
> +    }
> +#if defined(CPU_SAVE_VERSION)
> +    unregister_savevm(NULL, "cpu", cpu->env_ptr);
> +#endif
> +    if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> +        vmstate_unregister(NULL, &vmstate_cpu_common, cpu);
> +    }
>  }
>  #else
>  
> @@ -572,12 +583,20 @@ static int cpu_get_free_index(Error **errp)
>  
>  void cpu_exec_exit(CPUState *cpu)
>  {
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
> +
>      cpu_list_lock();
>      if (cpu->queued) {
>          QTAILQ_REMOVE(&cpus, cpu, node);
>          cpu->queued = false;
>      }
>      cpu_list_unlock();
> +    if (cc->vmsd != NULL) {
> +        vmstate_unregister(NULL, cc->vmsd, cpu);
> +    }
> +    if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> +        vmstate_unregister(NULL, &vmstate_cpu_common, cpu);
> +    }
>  }
>  #endif
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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