From ccbfa1d39b9e6d6e578176d091362287c53c7d4d Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Thu, 5 Oct 2017 18:54:24 -0700 Subject: [PATCH] KVM: LAPIC: Introduce limit_periodic_timer_frequency MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Extract the logic of limit lapic periodic timer frequency to a new function, this function will be used by later patches. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li Signed-off-by: Radim Krčmář --- arch/x86/kvm/lapic.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 6723e2ca3d9d..8841bb539c90 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -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 ", " -- 2.30.2