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KVM: LAPIC: Introduce limit_periodic_timer_frequency 

Extract the logic of limit lapic periodic timer frequency to a new function,
this function will be used by later patches.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
hifive-unleashed-5.1
Wanpeng Li 2017-10-05 18:54:24 -07:00 committed by Paolo Bonzini
parent c69518c86b
commit ccbfa1d39b
1 changed files with 22 additions and 17 deletions
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39
arch/x86/kvm/lapic.c
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@ -1301,6 +1301,27 @@ static void update_divide_count(struct kvm_lapic *apic)
apic->divide_count);
}
static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
{
/*
* Do not allow the guest to program periodic timers with small
* interval, since the hrtimers are not throttled by the host
* scheduler.
*/
if (apic_lvtt_period(apic)) {
s64 min_period = min_timer_period_us * 1000LL;
if (apic->lapic_timer.period < min_period) {
pr_info_ratelimited(
"kvm: vcpu %i: requested %lld ns "
"lapic timer period limited to %lld ns\n",
apic->vcpu->vcpu_id,
apic->lapic_timer.period, min_period);
apic->lapic_timer.period = min_period;
}
}
}
static void apic_update_lvtt(struct kvm_lapic *apic)
{
u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) &
@ -1445,23 +1466,7 @@ static bool set_target_expiration(struct kvm_lapic *apic)
if (!apic->lapic_timer.period)
return false;
/*
* Do not allow the guest to program periodic timers with small
* interval, since the hrtimers are not throttled by the host
* scheduler.
*/
if (apic_lvtt_period(apic)) {
s64 min_period = min_timer_period_us * 1000LL;
if (apic->lapic_timer.period < min_period) {
pr_info_ratelimited(
"kvm: vcpu %i: requested %lld ns "
"lapic timer period limited to %lld ns\n",
apic->vcpu->vcpu_id,
apic->lapic_timer.period, min_period);
apic->lapic_timer.period = min_period;
}
}
limit_periodic_timer_frequency(apic);
apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
PRIx64 ", "