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Date: Wed, 3 Feb 2016 17:23:05 +0100
From: Radim Krčmář <rkrcmar@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
Yuki Shibuya <shibuya.yk@...s.nec.co.jp>
Subject: [PATCH 4/4] KVM: x86: remove notifiers from PIT discard policy
Discard policy doesn't rely on information from notifiers, so we don't
need to register notifiers unconditionally.
Use of ps->lock doesn't make sense, but isn't any worse than before.
Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
---
arch/x86/kvm/i8254.c | 44 ++++++++++++++++++++++++++++++--------------
arch/x86/kvm/i8254.h | 1 +
arch/x86/kvm/x86.c | 6 +++---
3 files changed, 34 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index fc554fbf71a7..f1dfc250bbe0 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -237,9 +237,6 @@ static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
irq_ack_notifier);
- if (!ps->reinject)
- return;
-
atomic_set(&ps->irq_ack, 1);
if (atomic_add_unless(&ps->pending, -1, 0))
/* in this case, we had multiple outstanding pit interrupts
@@ -708,14 +705,13 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
pit_state->irq_ack_notifier.gsi = 0;
pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
- kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
- pit_state->reinject = true;
mutex_unlock(&pit->pit_state.lock);
- kvm_pit_reset(pit);
-
pit->mask_notifier.func = pit_mask_notifer;
- kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
+
+ kvm_pit_set_reinject(pit, true);
+
+ kvm_pit_reset(pit);
kvm_iodevice_init(&pit->dev, &pit_dev_ops);
ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
@@ -738,14 +734,37 @@ fail_unregister:
kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
fail:
- kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
- kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
+ kvm_pit_set_reinject(pit, false);
kvm_free_irq_source_id(kvm, pit->irq_source_id);
kthread_stop(pit->worker_task);
kfree(pit);
return NULL;
}
+void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject)
+{
+ /* Implicit BUG on NULL dereference. */
+ struct kvm_kpit_state *ps = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+
+ mutex_lock(&ps->lock);
+
+ if (ps->reinject == reinject)
+ goto out;
+
+ ps->reinject = reinject;
+ if (reinject) {
+ kvm_pit_reset_reinject(pit);
+ kvm_register_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
+ kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
+ } else {
+ kvm_unregister_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
+ kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
+ }
+out:
+ mutex_unlock(&ps->lock);
+}
+
void kvm_free_pit(struct kvm *kvm)
{
struct hrtimer *timer;
@@ -754,10 +773,7 @@ void kvm_free_pit(struct kvm *kvm)
kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
&kvm->arch.vpit->speaker_dev);
- kvm_unregister_irq_mask_notifier(kvm, 0,
- &kvm->arch.vpit->mask_notifier);
- kvm_unregister_irq_ack_notifier(kvm,
- &kvm->arch.vpit->pit_state.irq_ack_notifier);
+ kvm_pit_set_reinject(kvm->arch.vpit, false);
mutex_lock(&kvm->arch.vpit->pit_state.lock);
timer = &kvm->arch.vpit->pit_state.timer;
hrtimer_cancel(timer);
diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index f8cf4b84f435..7ac94bc0799f 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -60,5 +60,6 @@ void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_s
struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags);
void kvm_free_pit(struct kvm *kvm);
void kvm_pit_reset(struct kvm_pit *pit);
+void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject);
#endif
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5b937fdebc66..6bc03141e809 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3652,9 +3652,9 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm,
{
if (!kvm->arch.vpit)
return -ENXIO;
- mutex_lock(&kvm->arch.vpit->pit_state.lock);
- kvm->arch.vpit->pit_state.reinject = control->pit_reinject;
- mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+
+ kvm_pit_set_reinject(kvm->arch.vpit, control->pit_reinject);
+
return 0;
}
--
2.7.0
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