Commit a0aace5a authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
Browse files

KVM: i8254: turn kvm_kpit_state.reinject into atomic_t 



Document possible races between readers and concurrent update to the
ioctl.

Suggested-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ab4c1476

arch/x86/kvm/i8254.c

+4 −4
Original line number Diff line number Diff line
@@ -264,7 +264,7 @@ static void pit_do_work(struct kthread_work *work) 
	int i;

	struct kvm_kpit_state *ps = &pit->pit_state;



	if (ps->reinject && !atomic_xchg(&ps->irq_ack, 0))

	if (atomic_read(&ps->reinject) && !atomic_xchg(&ps->irq_ack, 0))

		return;



	kvm_set_irq(kvm, pit->irq_source_id, 0, 1, false);
@@ -289,7 +289,7 @@ static enum hrtimer_restart pit_timer_fn(struct hrtimer *data) 
	struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);

	struct kvm_pit *pt = pit_state_to_pit(ps);



	if (ps->reinject)

	if (atomic_read(&ps->reinject))

		atomic_inc(&ps->pending);



	queue_kthread_work(&pt->worker, &pt->expired);
@@ -312,7 +312,7 @@ void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject) 
	struct kvm_kpit_state *ps = &pit->pit_state;

	struct kvm *kvm = pit->kvm;



	if (ps->reinject == reinject)

	if (atomic_read(&ps->reinject) == reinject)

		return;



	if (reinject) {
@@ -325,7 +325,7 @@ void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject) 
		kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);

	}



	ps->reinject = reinject;

	atomic_set(&ps->reinject, reinject);

}



static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period)

arch/x86/kvm/i8254.h

+1 −1
Original line number Diff line number Diff line
@@ -31,7 +31,7 @@ struct kvm_kpit_state { 
	u32    speaker_data_on;



	struct mutex lock;

	bool reinject;

	atomic_t reinject;

	atomic_t pending; /* accumulated triggered timers */

	atomic_t irq_ack;

	struct kvm_irq_ack_notifier irq_ack_notifier;