Re: [PATCH RFC v2 2/4] Use pointer to vcpu instead of vcpu_id in timer code.

[Gleb Natapov <gleb@redhat.com>]

On Tue, May 26, 2009 at 11:30:21AM +0300, Avi Kivity wrote:
> Gleb Natapov wrote:
>> Signed-off-by: Gleb Natapov <gleb@redhat.com>
>> ---
>>  arch/x86/kvm/i8254.c     |    2 +-
>>  arch/x86/kvm/kvm_timer.h |    2 +-
>>  arch/x86/kvm/lapic.c     |    2 +-
>>  arch/x86/kvm/timer.c     |    2 +-
>>  4 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
>> index bcf755f..85d95ff 100644
>> --- a/arch/x86/kvm/i8254.c
>> +++ b/arch/x86/kvm/i8254.c
>> @@ -291,7 +291,7 @@ static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
>>  	pt->timer.function = kvm_timer_fn;
>>  	pt->t_ops = &kpit_ops;
>>  	pt->kvm = ps->pit->kvm;
>> -	pt->vcpu_id = 0;
>> +	pt->vcpu = pt->kvm->bsp_vcpu;
>>
>>   
>
> bsp_vcpu might not have been initialized at this time?
>
There is only two code path that may lead to this code. First one is
from pit_ioport_write() and at this stage BSP is already executing code
and thus exists. The second is during migration and vcpus are created
before incoming migration is accepted. May be BUG_ON() is appropriate
here.

--
			Gleb.