On Tue, Nov 23, 2021 at 09:46:34AM +0100, Paolo Bonzini wrote:

On 11/19/21 14:47, Chao Peng wrote:

quoted

+
+	/* 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