Re: [Qemu-devel] [PATCH 2/2] kvm: use per-cpu lock to free vcpu thread out of the big lock

[Jan Kiszka]

On 2012-06-21 16:49, Liu Ping Fan wrote:
> In order to break the big lock, using per-cpu_lock in kvm_cpu_exec()
> to protect the race from other cpu's access to env->apic_state & related
> field in env.
> Also, we need to protect agaist run_on_cpu().
> 
> Race condition can be like this:
> 1.  vcpu-1 IPI vcpu-2
>     vcpu-3 IPI vcpu-2
>     Open window exists for accessing to vcpu-2's apic_state & env
> 
> 2. run_on_cpu() write env->queued_work_last, while flush_queued_work()
>    read
> 

How much of this is still relevant with the (nowadays default-on)
in-kernel irqchips?

Jan

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