From: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Document possible races between readers and concurrent update to the
ioctl.
Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
v3: new
arch/x86/kvm/i8254.c | 8 ++++----
arch/x86/kvm/i8254.h | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 68af4445d51d..219ef855aae5 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -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)
diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index f365dce4fb8d..2f5af0798326 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -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;
--
2.7.2
--
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