From 8bc15d02d5fdff31bfeca02e58e22e26880dde39 Mon Sep 17 00:00:00 2001 From: Bibo Mao Date: Wed, 6 Mar 2024 09:12:13 +0800 Subject: LoongArch: KVM: Start SW timer only when vcpu is blocking SW timer is enabled when vcpu thread is scheduled out, and it is to wake up vcpu from blocked queue. If vcpu thread is scheduled out but is not blocked, such as it is preempted by other threads, it is not necessary to enable SW timer. Since vcpu thread is still on running queue if it is preempted and SW timer is only to wake up vcpu on blocking queue, so SW timer is not useful in this situation. This patch enables SW timer only when vcpu is scheduled out and is blocking. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen --- arch/loongarch/kvm/timer.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) (limited to 'arch/loongarch') diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c index 111328f60872..b0dafe0611ab 100644 --- a/arch/loongarch/kvm/timer.c +++ b/arch/loongarch/kvm/timer.c @@ -93,7 +93,8 @@ void kvm_restore_timer(struct kvm_vcpu *vcpu) /* * Freeze the soft-timer and sync the guest stable timer with it. */ - hrtimer_cancel(&vcpu->arch.swtimer); + if (kvm_vcpu_is_blocking(vcpu)) + hrtimer_cancel(&vcpu->arch.swtimer); /* * From LoongArch Reference Manual Volume 1 Chapter 7.6.2 @@ -168,26 +169,20 @@ static void _kvm_save_timer(struct kvm_vcpu *vcpu) * Here judge one-shot timer fired by checking whether TVAL is larger * than TCFG */ - if (ticks < cfg) { + if (ticks < cfg) delta = tick_to_ns(vcpu, ticks); - expire = ktime_add_ns(ktime_get(), delta); - vcpu->arch.expire = expire; + else + delta = 0; + + expire = ktime_add_ns(ktime_get(), delta); + vcpu->arch.expire = expire; + if (kvm_vcpu_is_blocking(vcpu)) { /* * HRTIMER_MODE_PINNED is suggested since vcpu may run in * the same physical cpu in next time */ hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); - } else if (vcpu->stat.generic.blocking) { - /* - * Inject timer interrupt so that halt polling can dectect and exit. - * VCPU is scheduled out already and sleeps in rcuwait queue and - * will not poll pending events again. kvm_queue_irq() is not enough, - * hrtimer swtimer should be used here. - */ - expire = ktime_add_ns(ktime_get(), 10); - vcpu->arch.expire = expire; - hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); } } -- cgit v1.2.3