diff options
| -rw-r--r-- | virt/kvm/arm/arch_timer.c | 75 |
1 files changed, 51 insertions, 24 deletions
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 7f4f12d..20e56c4 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -202,7 +202,27 @@ static enum hrtimer_restart kvm_bg_timer_expire(struct hrtimer *hrt) static enum hrtimer_restart kvm_phys_timer_expire(struct hrtimer *hrt) { - WARN(1, "Timer only used to ensure guest exit - unexpected event."); + struct arch_timer_context *ptimer; + struct arch_timer_cpu *timer; + struct kvm_vcpu *vcpu; + u64 ns; + + timer = container_of(hrt, struct arch_timer_cpu, phys_timer); + vcpu = container_of(timer, struct kvm_vcpu, arch.timer_cpu); + ptimer = vcpu_ptimer(vcpu); + + /* + * Check that the timer has really expired from the guest's + * PoV (NTP on the host may have forced it to expire + * early). If not ready, schedule for a later time. + */ + ns = kvm_timer_compute_delta(ptimer); + if (unlikely(ns)) { + hrtimer_forward_now(hrt, ns_to_ktime(ns)); + return HRTIMER_RESTART; + } + + kvm_timer_update_irq(vcpu, true, ptimer); return HRTIMER_NORESTART; } @@ -256,24 +276,28 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level, } /* Schedule the background timer for the emulated timer. */ -static void phys_timer_emulate(struct kvm_vcpu *vcpu, - struct arch_timer_context *timer_ctx) +static void phys_timer_emulate(struct kvm_vcpu *vcpu) { struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; + struct arch_timer_context *ptimer = vcpu_ptimer(vcpu); - if (kvm_timer_should_fire(timer_ctx)) - return; - - if (!kvm_timer_irq_can_fire(timer_ctx)) + /* + * If the timer can fire now we have just raised the IRQ line and we + * don't need to have a soft timer scheduled for the future. If the + * timer cannot fire at all, then we also don't need a soft timer. + */ + if (kvm_timer_should_fire(ptimer) || !kvm_timer_irq_can_fire(ptimer)) { + soft_timer_cancel(&timer->phys_timer, NULL); return; + } - /* The timer has not yet expired, schedule a background timer */ - soft_timer_start(&timer->phys_timer, kvm_timer_compute_delta(timer_ctx)); + soft_timer_start(&timer->phys_timer, kvm_timer_compute_delta(ptimer)); } /* - * Check if there was a change in the timer state (should we raise or lower - * the line level to the GIC). + * Check if there was a change in the timer state, so that we should either + * raise or lower the line level to the GIC or schedule a background timer to + * emulate the physical timer. */ static void kvm_timer_update_state(struct kvm_vcpu *vcpu) { @@ -295,6 +319,8 @@ static void kvm_timer_update_state(struct kvm_vcpu *vcpu) if (kvm_timer_should_fire(ptimer) != ptimer->irq.level) kvm_timer_update_irq(vcpu, !ptimer->irq.level, ptimer); + + phys_timer_emulate(vcpu); } static void vtimer_save_state(struct kvm_vcpu *vcpu) @@ -441,6 +467,9 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu) if (has_vhe()) disable_el1_phys_timer_access(); + + /* Set the background timer for the physical timer emulation. */ + phys_timer_emulate(vcpu); } bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu) @@ -476,12 +505,6 @@ void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) if (unlikely(!timer->enabled)) return; - - if (kvm_timer_should_fire(ptimer) != ptimer->irq.level) - kvm_timer_update_irq(vcpu, !ptimer->irq.level, ptimer); - - /* Set the background timer for the physical timer emulation. */ - phys_timer_emulate(vcpu, vcpu_ptimer(vcpu)); } void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) @@ -497,6 +520,17 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) vtimer_save_state(vcpu); /* + * Cancel the physical timer emulation, because the only case where we + * need it after a vcpu_put is in the context of a sleeping VCPU, and + * in that case we already factor in the deadline for the physical + * timer when scheduling the bg_timer. + * + * In any case, we re-schedule the hrtimer for the physical timer when + * coming back to the VCPU thread in kvm_timer_vcpu_load(). + */ + soft_timer_cancel(&timer->phys_timer, NULL); + + /* * The kernel may decide to run userspace after calling vcpu_put, so * we reset cntvoff to 0 to ensure a consistent read between user * accesses to the virtual counter and kernel access to the physical @@ -538,16 +572,9 @@ static void unmask_vtimer_irq(struct kvm_vcpu *vcpu) */ void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) { - struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; struct arch_timer_context *vtimer = vcpu_vtimer(vcpu); /* - * This is to cancel the background timer for the physical timer - * emulation if it is set. - */ - soft_timer_cancel(&timer->phys_timer, NULL); - - /* * If we entered the guest with the vtimer output asserted we have to * check if the guest has modified the timer so that we should lower * the line at this point. |
