Re: [Qemu-devel] [RFC] create a single workqueue for each vm to update vm irq routing table

[Zhanghaoyu (A)]

>> > I don't think a workqueue is even needed.  You just need to use 
>> > call_rcu to free "old" after releasing kvm->irq_lock.
>> > 
>> > What do you think?
>> 
>> It should be rate limited somehow. Since it guest triggarable guest 
>> may cause host to allocate a lot of memory this way.
>
Why does "use call_rcu to free "old" after releasing kvm->irq_lock" may cause 
host to allocate a lot of memory?
Do you mean that malicious guest's frequent irq-routing-table updating 
operations will result in too many delayed mem-free of old irq-routing-tables?

Thanks,
Zhang Haoyu

>True, though if I understand Zhanghaoyu's proposal a workqueue would be even 
>worse.
>

>Paolo