KVM: x86: Fix SRCU list traversal in kvm_fire_mask_notifiers()

The mask_notifier_list is protected by kvm->irq_srcu, but the traversal
in kvm_fire_mask_notifiers() incorrectly uses hlist_for_each_entry_rcu().
This leads to lockdep warnings because the standard RCU iterator expects
to be under rcu_read_lock(), not SRCU.

Replace the RCU variant with hlist_for_each_entry_srcu() and provide
the proper srcu_read_lock_held() annotation to ensure correct
synchronization and silence lockdep.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://patch.msgid.link/20260204091206.2617-1-lirongqing@baidu.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: lrq-max

arch/x86/kvm/ioapic.c

@@ -321,7 +321,8 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
 	idx = srcu_read_lock(&kvm->irq_srcu);
 	gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
 	if (gsi != -1)
-		hlist_for_each_entry_rcu(kimn, &ioapic->mask_notifier_list, link)
+		hlist_for_each_entry_srcu(kimn, &ioapic->mask_notifier_list, link,
+				srcu_read_lock_held(&kvm->irq_srcu))
 			if (kimn->irq == gsi)
 				kimn->func(kimn, mask);
 	srcu_read_unlock(&kvm->irq_srcu, idx);