From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v9 3/3] x86, apicv: add virtual interrupt delivery support
Date: Fri, 11 Jan 2013 15:58:36 -0200
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Cc: Yang Zhang <yang.z.zhang@intel.com>, kvm@vger.kernel.org,
	haitao.shan@intel.com, Kevin Tian <kevin.tian@intel.com>
To: Gleb Natapov <gleb@redhat.com>
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> > 
> > Move inside irq_lock protection.
> > 
> > >  
> > >  void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
> > > @@ -270,6 +291,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
> > >  	hlist_del_init_rcu(&kian->link);
> > >  	mutex_unlock(&kvm->irq_lock);
> > >  	synchronize_rcu();
> > > +	ioapic_update_eoi_exitmap(kvm);
> > 
> > Move both synchronize_rcu and ioapic_update_eoi_exitmap inside irq_lock
> > protection.
> Why? (here and one above). If vcpu uses stale data during update it will
> find recalculate request during guest entry and will recalculate again.
> 
> --
> 			Gleb.

Indeed, its not necessary and also not necessary to grab irq_lock during 
vcpu entry, while processing the KVM_REQ_ bit.