From a0aace5ac0efdb2bcb71e10d9c9ca6a851fa59f9 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Date: Wed, 2 Mar 2016 22:56:52 +0100 Subject: [PATCH] KVM: i8254: turn kvm_kpit_state.reinject into atomic_t MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Document possible races between readers and concurrent update to the ioctl. Suggested-by: Paolo Bonzini Signed-off-by: Radim Krčmář Signed-off-by: Paolo Bonzini --- 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; -- 2.20.1