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Subject[PATCH 2/3] KVM: lapic: reorganize restart_apic_timer
Date
Move the code to cancel the hv timer into the caller, just before
it starts the hrtimer. Check availability of the hv timer in
start_hv_timer.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/lapic.c | 85 +++++++++++++++++++++++++---------------------------
arch/x86/kvm/lapic.h | 2 +-
arch/x86/kvm/x86.c | 8 ++---
3 files changed, 45 insertions(+), 50 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b6689dcae1da..a80e5a5d6f2f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1495,17 +1495,21 @@ bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)

static void cancel_hv_timer(struct kvm_lapic *apic)
{
+ WARN_ON(!apic->lapic_timer.hv_timer_in_use);
preempt_disable();
kvm_x86_ops->cancel_hv_timer(apic->vcpu);
apic->lapic_timer.hv_timer_in_use = false;
preempt_enable();
}

-static bool __start_hv_timer(struct kvm_lapic *apic)
+static bool start_hv_timer(struct kvm_lapic *apic)
{
struct kvm_timer *ktimer = &apic->lapic_timer;
int r;

+ if (!kvm_x86_ops->set_hv_timer)
+ return false;
+
if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
return false;

@@ -1523,19 +1527,30 @@ static bool __start_hv_timer(struct kvm_lapic *apic)
*/
if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
return false;
+
+ trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, true);
return true;
}

-static bool start_hv_timer(struct kvm_lapic *apic)
+static void start_sw_timer(struct kvm_lapic *apic)
{
- if (!__start_hv_timer(apic)) {
- if (apic->lapic_timer.hv_timer_in_use)
- cancel_hv_timer(apic);
- }
+ struct kvm_timer *ktimer = &apic->lapic_timer;
+ if (apic->lapic_timer.hv_timer_in_use)
+ cancel_hv_timer(apic);
+ if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
+ return;
+
+ if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
+ start_sw_period(apic);
+ else if (apic_lvtt_tscdeadline(apic))
+ start_sw_tscdeadline(apic);
+ trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, false);
+}

- trace_kvm_hv_timer_state(apic->vcpu->vcpu_id,
- apic->lapic_timer.hv_timer_in_use);
- return apic->lapic_timer.hv_timer_in_use;
+static void restart_apic_timer(struct kvm_lapic *apic)
+{
+ if (!start_hv_timer(apic))
+ start_sw_timer(apic);
}

void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu)
@@ -1549,19 +1564,14 @@ void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu)

if (apic_lvtt_period(apic) && apic->lapic_timer.period) {
advance_periodic_target_expiration(apic);
- if (!start_hv_timer(apic))
- start_sw_period(apic);
+ restart_apic_timer(apic);
}
}
EXPORT_SYMBOL_GPL(kvm_lapic_expired_hv_timer);

void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu)
{
- struct kvm_lapic *apic = vcpu->arch.apic;
-
- WARN_ON(apic->lapic_timer.hv_timer_in_use);
-
- start_hv_timer(apic);
+ restart_apic_timer(vcpu->arch.apic);
}
EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_hv_timer);

@@ -1570,33 +1580,28 @@ void kvm_lapic_switch_to_sw_timer(struct kvm_vcpu *vcpu)
struct kvm_lapic *apic = vcpu->arch.apic;

/* Possibly the TSC deadline timer is not enabled yet */
- if (!apic->lapic_timer.hv_timer_in_use)
- return;
-
- cancel_hv_timer(apic);
+ if (apic->lapic_timer.hv_timer_in_use)
+ start_sw_timer(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);

- if (atomic_read(&apic->lapic_timer.pending))
- return;
+void kvm_lapic_restart_hv_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;

- if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
- start_sw_period(apic);
- else if (apic_lvtt_tscdeadline(apic))
- start_sw_tscdeadline(apic);
+ WARN_ON(!apic->lapic_timer.hv_timer_in_use);
+ restart_apic_timer(apic);
}
-EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);

static void start_apic_timer(struct kvm_lapic *apic)
{
atomic_set(&apic->lapic_timer.pending, 0);

- if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
- if (set_target_expiration(apic) &&
- !(kvm_x86_ops->set_hv_timer && start_hv_timer(apic)))
- start_sw_period(apic);
- } else if (apic_lvtt_tscdeadline(apic)) {
- if (!(kvm_x86_ops->set_hv_timer && start_hv_timer(apic)))
- start_sw_tscdeadline(apic);
- }
+ if ((apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
+ && !set_target_expiration(apic))
+ return;
+
+ restart_apic_timer(apic);
}

static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
@@ -1827,16 +1832,6 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu)
* LAPIC interface
*----------------------------------------------------------------------
*/
-u64 kvm_get_lapic_target_expiration_tsc(struct kvm_vcpu *vcpu)
-{
- struct kvm_lapic *apic = vcpu->arch.apic;
-
- if (!lapic_in_kernel(vcpu))
- return 0;
-
- return apic->lapic_timer.tscdeadline;
-}
-
u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index bcbe811f3b97..29caa2c3dff9 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -87,7 +87,6 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);

-u64 kvm_get_lapic_target_expiration_tsc(struct kvm_vcpu *vcpu);
u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu);
void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data);

@@ -216,4 +215,5 @@ int kvm_vector_to_index(u32 vector, u32 dest_vcpus,
void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu);
void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu);
bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu);
+void kvm_lapic_restart_hv_timer(struct kvm_vcpu *vcpu);
#endif
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a2cd0997343c..81aa9c321be3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2841,10 +2841,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_vcpu_write_tsc_offset(vcpu, offset);
vcpu->arch.tsc_catchup = 1;
}
- if (kvm_lapic_hv_timer_in_use(vcpu) &&
- kvm_x86_ops->set_hv_timer(vcpu,
- kvm_get_lapic_target_expiration_tsc(vcpu)))
- kvm_lapic_switch_to_sw_timer(vcpu);
+
+ if (kvm_lapic_hv_timer_in_use(vcpu))
+ kvm_lapic_restart_hv_timer(vcpu);
+
/*
* On a host with synchronized TSC, there is no need to update
* kvmclock on vcpu->cpu migration
--
1.8.3.1

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