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KVM: i8254: turn kvm_kpit_state.reinject into atomic_t 

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

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Radim Krčmář 2016-03-02 22:56:52 +01:00 committed by Paolo Bonzini
parent ab4c14763b
commit a0aace5ac0
2 changed files with 5 additions and 5 deletions
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8
arch/x86/kvm/i8254.c
View File

@ -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)

2
arch/x86/kvm/i8254.h
View File

@ -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;