Re: [RFC v2 PATCH 09/13] KVM: Introduce kvm_memfd_invalidate_range

[Chao Peng]

On Tue, Nov 23, 2021 at 09:46:34AM +0100, Paolo Bonzini wrote:
> On 11/19/21 14:47, Chao Peng wrote:
> > +
> > +	/* Prevent memslot modification */
> > +	spin_lock(&kvm->mn_invalidate_lock);
> > +	kvm->mn_active_invalidate_count++;
> > +	spin_unlock(&kvm->mn_invalidate_lock);
> > +
> > +	ret = __kvm_handle_useraddr_range(kvm, &useraddr_range);
> > +
> > +	spin_lock(&kvm->mn_invalidate_lock);
> > +	kvm->mn_active_invalidate_count--;
> > +	spin_unlock(&kvm->mn_invalidate_lock);
> > +
> 
> 
> You need to follow this with a rcuwait_wake_up as in
> kvm_mmu_notifier_invalidate_range_end.

Oh right.

> 
> It's probably best if you move the manipulations of
> mn_active_invalidate_count from kvm_mmu_notifier_invalidate_range_* to two
> separate functions.

Will do.

> 
> Paolo