diff mbox series

[v3,8/9] KVM: lapic: Check for a pending timer intr prior to start_hv_timer()

Message ID 20190416203248.29429-9-sean.j.christopherson@intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: lapic: Fix a variety of timer adv issues | expand

Commit Message

Sean Christopherson April 16, 2019, 8:32 p.m. UTC 
Checking for a pending non-periodic interrupt in start_hv_timer() leads
to restart_apic_timer() making an unnecessary call to start_sw_timer()
due to start_hv_timer() returning false.

Alternatively, start_hv_timer() could return %true when there is a
pending non-periodic interrupt, but that approach is less intuitive,
i.e. would require a beefy comment to explain an otherwise simple check.

Cc: Liran Alon <liran.alon@oracle.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Suggested-by: Liran Alon <liran.alon@oracle.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/lapic.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 9a09a41000c3..32b05ca2f70a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1688,9 +1688,6 @@  static bool start_hv_timer(struct kvm_lapic *apic)
 	if (!kvm_x86_ops->set_hv_timer)
 		return false;
 
-	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
-		return false;
-
 	if (!ktimer->tscdeadline)
 		return false;
 
@@ -1743,8 +1740,13 @@  static void start_sw_timer(struct kvm_lapic *apic)
 static void restart_apic_timer(struct kvm_lapic *apic)
 {
 	preempt_disable();
+
+	if (!apic_lvtt_period(apic) && atomic_read(&apic->lapic_timer.pending))
+		goto out;
+
 	if (!start_hv_timer(apic))
 		start_sw_timer(apic);
+out:
 	preempt_enable();
 }