diff options
Diffstat (limited to 'virt/kvm/arm/arch_timer.c')
| -rw-r--r-- | virt/kvm/arm/arch_timer.c | 81 |
1 files changed, 56 insertions, 25 deletions
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 32095fbb5d7c..523816d8c402 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -59,18 +59,6 @@ static void timer_disarm(struct arch_timer_cpu *timer) } } -static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu) -{ - int ret; - struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; - - kvm_vgic_set_phys_irq_active(timer->map, true); - ret = kvm_vgic_inject_mapped_irq(vcpu->kvm, vcpu->vcpu_id, - timer->map, - timer->irq->level); - WARN_ON(ret); -} - static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) { struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id; @@ -116,8 +104,7 @@ static bool kvm_timer_irq_can_fire(struct kvm_vcpu *vcpu) struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; return !(timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) && - (timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE) && - !kvm_vgic_get_phys_irq_active(timer->map); + (timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE); } bool kvm_timer_should_fire(struct kvm_vcpu *vcpu) @@ -134,6 +121,41 @@ bool kvm_timer_should_fire(struct kvm_vcpu *vcpu) return cval <= now; } +static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level) +{ + int ret; + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; + + BUG_ON(!vgic_initialized(vcpu->kvm)); + + timer->irq.level = new_level; + ret = kvm_vgic_inject_mapped_irq(vcpu->kvm, vcpu->vcpu_id, + timer->map, + timer->irq.level); + WARN_ON(ret); +} + +/* + * Check if there was a change in the timer state (should we raise or lower + * the line level to the GIC). + */ +static void kvm_timer_update_state(struct kvm_vcpu *vcpu) +{ + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; + + /* + * If userspace modified the timer registers via SET_ONE_REG before + * the vgic was initialized, we mustn't set the timer->irq.level value + * because the guest would never see the interrupt. Instead wait + * until we call this function from kvm_timer_flush_hwstate. + */ + if (!vgic_initialized(vcpu->kvm)) + return; + + if (kvm_timer_should_fire(vcpu) != timer->irq.level) + kvm_timer_update_irq(vcpu, !timer->irq.level); +} + /* * Schedule the background timer before calling kvm_vcpu_block, so that this * thread is removed from its waitqueue and made runnable when there's a timer @@ -192,17 +214,20 @@ void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) bool phys_active; int ret; - if (kvm_timer_should_fire(vcpu)) - kvm_timer_inject_irq(vcpu); + kvm_timer_update_state(vcpu); /* - * We keep track of whether the edge-triggered interrupt has been - * signalled to the vgic/guest, and if so, we mask the interrupt and - * the physical distributor to prevent the timer from raising a - * physical interrupt whenever we run a guest, preventing forward - * VCPU progress. + * If we enter the guest with the virtual input level to the VGIC + * asserted, then we have already told the VGIC what we need to, and + * we don't need to exit from the guest until the guest deactivates + * the already injected interrupt, so therefore we should set the + * hardware active state to prevent unnecessary exits from the guest. + * + * Conversely, if the virtual input level is deasserted, then always + * clear the hardware active state to ensure that hardware interrupts + * from the timer triggers a guest exit. */ - if (kvm_vgic_get_phys_irq_active(timer->map)) + if (timer->irq.level) phys_active = true; else phys_active = false; @@ -226,8 +251,11 @@ void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) BUG_ON(timer_is_armed(timer)); - if (kvm_timer_should_fire(vcpu)) - kvm_timer_inject_irq(vcpu); + /* + * The guest could have modified the timer registers or the timer + * could have expired, update the timer state. + */ + kvm_timer_update_state(vcpu); } int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, @@ -242,7 +270,7 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, * kvm_vcpu_set_target(). To handle this, we determine * vcpu timer irq number when the vcpu is reset. */ - timer->irq = irq; + timer->irq.irq = irq->irq; /* * The bits in CNTV_CTL are architecturally reset to UNKNOWN for ARMv8 @@ -251,6 +279,7 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, * the ARMv7 architecture. */ timer->cntv_ctl = 0; + kvm_timer_update_state(vcpu); /* * Tell the VGIC that the virtual interrupt is tied to a @@ -295,6 +324,8 @@ int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value) default: return -1; } + + kvm_timer_update_state(vcpu); return 0; } |