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Re: [PATCH v3 1/5] evtchn: drop acquiring of per-channel lock from send_guest_{global,vcpu}_virq()



Hi Jan,

On 23/11/2020 13:28, Jan Beulich wrote:
The per-vCPU virq_lock, which is being held anyway, together with there
not being any call to evtchn_port_set_pending() when v->virq_to_evtchn[]
is zero, provide sufficient guarantees.

I agree that the per-vCPU virq_lock is going to be sufficient, however dropping the lock also means the event channel locking is more complex to understand (the long comment that was added proves it).

In fact, the locking in the event channel code was already proven to be quite fragile, therefore I think this patch is not worth the risk.

Cheers,

--
Julien Grall



 


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