Re: [PATCH 03/12] Remove KVM_REQ_PENDING_TIMER.

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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

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