Re: [Qemu-devel] [RFC V2 04/10] x86: add x86_cpu_unrealizefn() for cpu apic remove

[Gu Zheng]

Hi Igor,

On 09/09/2014 09:58 PM, Igor Mammedov wrote:

> On Thu, 28 Aug 2014 11:36:36 +0800
> Gu Zheng <address@hidden> wrote:
> 
>> From: Chen Fan <address@hidden>
>>
>> Implement x86_cpu_unrealizefn() for corresponding x86_cpu_realizefn(),
>> which is mostly used to clean the apic related allocation and vmstates
>> at here.
>>
>> Signed-off-by: Chen Fan <address@hidden>
>> Signed-off-by: Gu Zheng <address@hidden>
>> ---
>>  hw/i386/kvm/apic.c              |    8 +++++++
>>  hw/intc/apic.c                  |   10 ++++++++
>>  hw/intc/apic_common.c           |   23 +++++++++++++++++++-
>>  include/hw/cpu/icc_bus.h        |    1 +
>>  include/hw/i386/apic_internal.h |    1 +
>>  target-i386/cpu-qom.h           |    1 +
>>  target-i386/cpu.c               |   45 
>> +++++++++++++++++++++++++++++++++++++++
>>  7 files changed, 88 insertions(+), 1 deletions(-)
>>
>> diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c
>> index e873b50..c95fb8a 100644
>> --- a/hw/i386/kvm/apic.c
>> +++ b/hw/i386/kvm/apic.c
>> @@ -183,11 +183,19 @@ static void kvm_apic_realize(DeviceState *dev, Error 
>> **errp)
>>      }
>>  }
>>  
>> +static void kvm_apic_unrealize(DeviceState *dev, Error **errp)
>> +{
>> +    APICCommonState *s = APIC_COMMON(dev);
>> +
>> +    object_unparent(OBJECT(&s->io_memory));
>> +}
>> +
> what will disable/destroy in kernel APIC?

As we parked kvm cpu, is this step still seriously needed?

> 
>>  static void kvm_apic_class_init(ObjectClass *klass, void *data)
>>  {
>>      APICCommonClass *k = APIC_COMMON_CLASS(klass);
>>  
>>      k->realize = kvm_apic_realize;
>> +    k->unrealize = kvm_apic_unrealize;
>>      k->set_base = kvm_apic_set_base;
>>      k->set_tpr = kvm_apic_set_tpr;
>>      k->get_tpr = kvm_apic_get_tpr;
>> diff --git a/hw/intc/apic.c b/hw/intc/apic.c
>> index 03ff9e9..6d38965 100644
>> --- a/hw/intc/apic.c
>> +++ b/hw/intc/apic.c
>> @@ -885,11 +885,21 @@ static void apic_realize(DeviceState *dev, Error 
>> **errp)
>>      msi_supported = true;
>>  }
>>  
>> +static void apic_unrealize(DeviceState *dev, Error **errp)
>> +{
>> +    APICCommonState *s = APIC_COMMON(dev);
>> +
>> +    object_unparent(OBJECT(&s->io_memory));
>> +    timer_free(s->timer);
>> +    local_apics[s->idx] = NULL;
>> +}
>> +
>>  static void apic_class_init(ObjectClass *klass, void *data)
>>  {
>>      APICCommonClass *k = APIC_COMMON_CLASS(klass);
>>  
>>      k->realize = apic_realize;
>> +    k->unrealize = apic_unrealize;
>>      k->set_base = apic_set_base;
>>      k->set_tpr = apic_set_tpr;
>>      k->get_tpr = apic_get_tpr;
>> diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
>> index 029f67d..8d17be1 100644
>> --- a/hw/intc/apic_common.c
>> +++ b/hw/intc/apic_common.c
>> @@ -289,12 +289,13 @@ static int apic_load_old(QEMUFile *f, void *opaque, 
>> int version_id)
>>      return 0;
>>  }
>>  
>> +static int apic_no;
>> +
> some apic code still assumes that index in local_apics[] is APIC ID, so
> apic_no and related stuff won't work with arbitrary CPU hotadd (i.e. 
> arbitrary APIC ID)
> to make it work the APICCommonState.idx should be dropped altogether and
> replaced with apic_id.

If so, we absolutely need to change this. 

> 
> I addition intc/apic.c is designed for APIC ID 8-bit max, we probably should 
> add
> some assert there so it wouldn't break silently when APIC ID goes above this
> maximum.

OK.

> 
>>  static void apic_common_realize(DeviceState *dev, Error **errp)
>>  {
>>      APICCommonState *s = APIC_COMMON(dev);
>>      APICCommonClass *info;
>>      static DeviceState *vapic;
>> -    static int apic_no;
>>      static bool mmio_registered;
>>  
>>      if (apic_no >= MAX_APICS) {
>> @@ -324,6 +325,25 @@ static void apic_common_realize(DeviceState *dev, Error 
>> **errp)
>>  
>>  }
>>  
>> +static void apic_common_unrealize(DeviceState *dev, Error **errp)
>> +{
>> +    APICCommonState *s = APIC_COMMON(dev);
>> +    APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
>> +
>> +    if (apic_no <= 0) {
>> +        error_setg(errp, "%s exit failed.",
>> +                   object_get_typename(OBJECT(dev)));
>> +        return;
>> +    }
>> +    apic_no--;
>> +
>> +    info->unrealize(dev, errp);
>> +
>> +    if (apic_report_tpr_access && info->enable_tpr_reporting) {
>> +        info->enable_tpr_reporting(s, false);
>> +    }
> what about unrealizing vapic?

IMO, we should not unrealize the vapic, because all apics share one vapic.

> 
> 
>> +}
>> +
>>  static void apic_dispatch_pre_save(void *opaque)
>>  {
>>      APICCommonState *s = APIC_COMMON(opaque);
>> @@ -394,6 +414,7 @@ static void apic_common_class_init(ObjectClass *klass, 
>> void *data)
>>      dc->reset = apic_reset_common;
>>      dc->props = apic_properties_common;
>>      idc->realize = apic_common_realize;
>> +    idc->unrealize = apic_common_unrealize;
>>      /*
>>       * Reason: APIC and CPU need to be wired up by
>>       * x86_cpu_apic_create()
>> diff --git a/include/hw/cpu/icc_bus.h b/include/hw/cpu/icc_bus.h
>> index 98a979f..75ed309 100644
>> --- a/include/hw/cpu/icc_bus.h
>> +++ b/include/hw/cpu/icc_bus.h
>> @@ -67,6 +67,7 @@ typedef struct ICCDeviceClass {
>>      /*< public >*/
>>  
>>      DeviceRealize realize;
>> +    DeviceUnrealize unrealize;
>>  } ICCDeviceClass;
>>  
>>  #define TYPE_ICC_DEVICE "icc-device"
>> diff --git a/include/hw/i386/apic_internal.h 
>> b/include/hw/i386/apic_internal.h
>> index 2c91609..6c9e390 100644
>> --- a/include/hw/i386/apic_internal.h
>> +++ b/include/hw/i386/apic_internal.h
>> @@ -82,6 +82,7 @@ typedef struct APICCommonClass
>>      ICCDeviceClass parent_class;
>>  
>>      DeviceRealize realize;
>> +    DeviceUnrealize unrealize;
>>      void (*set_base)(APICCommonState *s, uint64_t val);
>>      void (*set_tpr)(APICCommonState *s, uint8_t val);
>>      uint8_t (*get_tpr)(APICCommonState *s);
>> diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
>> index 71a1b97..2239105 100644
>> --- a/target-i386/cpu-qom.h
>> +++ b/target-i386/cpu-qom.h
>> @@ -65,6 +65,7 @@ typedef struct X86CPUClass {
>>      bool kvm_required;
>>  
>>      DeviceRealize parent_realize;
>> +    DeviceUnrealize parent_unrealize;
>>      void (*parent_reset)(CPUState *cpu);
>>  } X86CPUClass;
>>  
>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>> index 5255ddb..72a94a6 100644
>> --- a/target-i386/cpu.c
>> +++ b/target-i386/cpu.c
>> @@ -2712,10 +2712,32 @@ static void x86_cpu_apic_realize(X86CPU *cpu, Error 
>> **errp)
>>          return;
>>      }
>>  }
>> +
>> +static void x86_cpu_apic_unrealize(X86CPU *cpu, Error **errp)
>> +{
>> +    Error *local_err = NULL;
>> +
>> +    if (cpu->apic_state == NULL) {
>> +        return;
>> +    }
>> +
>> +    object_property_set_bool(OBJECT(cpu->apic_state),
>> +                             false, "realized", &local_err);
>> +    if (local_err != NULL) {
>> +        error_propagate(errp, local_err);
>> +        return;
>> +    }
>> +
>> +    vmstate_unregister(NULL, &vmstate_apic_common, cpu->apic_state);
> this should be done by device_unrealize when APIC is being unrealized.

Yes, I will fix it.

> 
>> +    object_unparent(OBJECT(cpu->apic_state));
>> +}
>>  #else
>>  static void x86_cpu_apic_realize(X86CPU *cpu, Error **errp)
>>  {
>>  }
>> +static void x86_cpu_apic_unrealize(X86CPU *cpu, Error **errp)
>> +{
>> +}
>>  #endif
>>  
>>  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
>> @@ -2778,6 +2800,27 @@ out:
>>      }
>>  }
>>  
>> +static void x86_cpu_unrealizefn(DeviceState *dev, Error **errp)
>> +{
>> +    X86CPU *cpu = X86_CPU(dev);
>> +    CPUClass *cc = CPU_GET_CLASS(dev);
>> +    Error *local_err = NULL;
>> +
>> +    if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
>> +        vmstate_unregister(NULL, &vmstate_cpu_common, cpu);
>> +    }
>> +
>> +    if (cc->vmsd != NULL) {
>> +        vmstate_unregister(NULL, cc->vmsd, cpu);
>> +    }
> I don't recall which variant x86cpu uses but it probably should be
> one of above
> or even better, make device_set_realized()->vmstate_[un]register*() work
> wit x86cpu if possible.

I'll try this way, thanks.

Regards,
Gu

> 
>> +
>> +    x86_cpu_apic_unrealize(cpu, &local_err);
>> +    if (local_err != NULL) {
>> +        error_propagate(errp, local_err);
>> +        return;
>> +    }
>> +}
>> +
>>  /* Enables contiguous-apic-ID mode, for compatibility */
>>  static bool compat_apic_id_mode;
>>  
>> @@ -2957,7 +3000,9 @@ static void x86_cpu_common_class_init(ObjectClass *oc, 
>> void *data)
>>      DeviceClass *dc = DEVICE_CLASS(oc);
>>  
>>      xcc->parent_realize = dc->realize;
>> +    xcc->parent_unrealize = dc->unrealize;
>>      dc->realize = x86_cpu_realizefn;
>> +    dc->unrealize = x86_cpu_unrealizefn;
>>      dc->bus_type = TYPE_ICC_BUS;
>>      dc->props = x86_cpu_properties;
>>  
> 
> .
>