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

[Chen Fan]

On 03/06/2015 04:53 PM, Igor Mammedov wrote:
> On Fri, 13 Feb 2015 18:25:28 +0800
> Zhu Guihua <address@hidden> 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.
> >
> > 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;
> Why do you add max_cpus here?
Adding max_cpus is to avoid cpu_index equals comat_index which would
cause migration fails,  this reason is that find_se() always compares 
instance_id
with se->instance_id or se->alias_id when do migration.

Thanks,
Chen

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