Re: [PATCH 03/12] Remove KVM_REQ_PENDING_TIMER.

[Avi Kivity <avi@redhat.com>]

On 12/02/2009 04:16 PM, Avi Kivity wrote:
>
>> Unfortunately, this does sort of put a damper on what's going on later
>> in the series.  If the i8254 doesn't belong to the BSP (which it really
>> shouldn't), then I don't know which vcpu to raise the bit on.  Maybe I
>> can do it in the kvm_irq_delivery_to_apic() function, or
>> kvm_apic_set_irq().  I'll take a look at that.
>
> We shouldn't have that bit at all.
>
> An alternative is to make the pic/ioapic work in irq context 
> (spin_lock_irq() and friends) and queue the interrupt directly from 
> the hrtimer instead of the vcpu.  My worry is that we have quite a bit 
> of work to do in irq context if the interrupt is broadcast and if we 
> have many vcpus; maybe we can use a work_struct in that case.
>

er, you do that later on.  In this case nothing blocks the removal of 
the bit - if the timer causes an interrupt to be injected, then the 
lapic/irq code will send an IPI to the vcpu to cause it to resample.  
See __apic_accept_irq() in lapic.c calling kvm_vcpu_kick(), for example.

The only issue is the ordering of the patches, you can only remove 
KVM_REQ_PENDING_TIMER after rearranging interrupt injection to happen 
inline.

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