Re: [PATCH] KVM: x86: Kick VCPU outside PIC lock again

Avi Kivity
2010-02-24T10:27:59Z

On 02/24/2010 12:22 PM, Jan Kiszka wrote:
> Avi Kivity wrote:
>
>> On 02/24/2010 12:13 PM, Jan Kiszka wrote:
>>
>>>
>>>
>>>> I see. Won't we hit the same issue when we call pic functions from
>>>> atomic context during the guest entry sequence?
>>>>
>>>>
>>>>
>>> If there are such call paths, for sure. What concrete path(s) do you
>>> have in mind?
>>>
>>>
>>>
>> vcpu_enter_guest() -> inject_pending_event() ->
>> kvm_cpu_{has,get}_interrupt() -> various pic functions if you're unlucky.
>>
> But do they kick anyone or just check/pull information?

Probably not, kicking should be a side effect (or rather the main
effect) of queueing an interrupt, not dequeuing it.

> Never saw any
> warnings during my tests last year (granted: with older -rt and kvm
> versions).
>

Well, most guests kill the pic early on. Will apply the patch.

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