Commit f1ba5cfb authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini

KVM: lapic: Explicitly cancel the hv timer if it's pre-expired

Explicitly call cancel_hv_timer() instead of returning %false to coerce
restart_apic_timer() into canceling it by way of start_sw_timer().

Functionally, the existing code is correct in the sense that it doesn't
doing anything visibily wrong, e.g. generate spurious interrupts or miss
an interrupt.  But it's extremely confusing and inefficient, e.g. there
are multiple extraneous calls to apic_timer_expired() that effectively
get dropped due to @timer_pending being %true.

Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ee66e453
...@@ -1693,17 +1693,25 @@ static bool start_hv_timer(struct kvm_lapic *apic) ...@@ -1693,17 +1693,25 @@ static bool start_hv_timer(struct kvm_lapic *apic)
hrtimer_cancel(&ktimer->timer); hrtimer_cancel(&ktimer->timer);
/* /*
* Also recheck ktimer->pending, in case the sw timer triggered in * To simplify handling the periodic timer, leave the hv timer running
* the window. For periodic timer, leave the hv timer running for * even if the deadline timer has expired, i.e. rely on the resulting
* simplicity, and the deadline will be recomputed on the next vmexit. * VM-Exit to recompute the periodic timer's target expiration.
*/ */
if (!apic_lvtt_period(apic) && (r || atomic_read(&ktimer->pending))) { if (!apic_lvtt_period(apic)) {
if (r) /*
* Cancel the hv timer if the sw timer fired while the hv timer
* was being programmed, or if the hv timer itself expired.
*/
if (atomic_read(&ktimer->pending)) {
cancel_hv_timer(apic);
} else if (r) {
apic_timer_expired(apic); apic_timer_expired(apic);
return false; cancel_hv_timer(apic);
} }
}
trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, ktimer->hv_timer_in_use);
trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, true);
return true; return true;
} }
......
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