Re: live migration between kernel/user irqchip

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Dong, Eddie wrote:
> Avi Kivity wrote:
>   
>> Dong, Eddie wrote:
>>     
>>> When thinking about live migration support for in kernel irqchip, one
>>> question comes out which need to be solved first:
>>> Do we need to support live migration among user level irqchip and
>>> kernel level?
>>>       
>> Yes.
>>
>>     
>>> If the answer is yes, kernel level irqchip must keep same state
>>> with user level, i.e. if Qemu changes the pic/apic/ioapic state
>>> definition, we need to do corresponding changes too, otherwise
>>> kernel side can stay as it is. 
>>>
>>>       
>> The qemu state mimics the device state and should be independent of
>> implementation details.  If the qemu state is added too, this most
>> likely indicates a but that needs to be fixed in kvm as well.
>>
>> The best way to do live migration is to copy the kernel state into the
>> qemu device model, and let qemu do state serialization.  This ensures
>>     
>
> "copy" means we define some device "state" both in kernel & user. 
> I.e.  kernel use user level state definition.
>   

Sorry, I don't understand.

Here's apic_save(), for example:

static void apic_save(QEMUFile *f, void *opaque)
{
    APICState *s = opaque;
    int i;

    qemu_put_be32s(f, &s->apicbase);
    qemu_put_8s(f, &s->id);
    qemu_put_8s(f, &s->arb_id);
    qemu_put_8s(f, &s->tpr);
    qemu_put_be32s(f, &s->spurious_vec);
    qemu_put_8s(f, &s->log_dest);
    qemu_put_8s(f, &s->dest_mode);
    for (i = 0; i < 8; i++) {
        qemu_put_be32s(f, &s->isr[i]);
        qemu_put_be32s(f, &s->tmr[i]);
        qemu_put_be32s(f, &s->irr[i]);
    }
    for (i = 0; i < APIC_LVT_NB; i++) {
        qemu_put_be32s(f, &s->lvt[i]);
    }
    qemu_put_be32s(f, &s->esr);
    qemu_put_be32s(f, &s->icr[0]);
    qemu_put_be32s(f, &s->icr[1]);
    qemu_put_be32s(f, &s->divide_conf);
    qemu_put_be32s(f, &s->count_shift);
    qemu_put_be32s(f, &s->initial_count);
    qemu_put_be64s(f, &s->initial_count_load_time);
    qemu_put_be64s(f, &s->next_time);

    qemu_put_timer(f, s->timer);
}

Do you see state here that does not exist in the kernel?  Or kernel 
state that is missing from here?

->timer and ->next_time may be non-trivial, but both are needed.

-- 
error compiling committee.c: too many arguments to function


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