Re: [RFC v2 06/10] KVM: arm/arm64: Update the physical timer interrupt level
From: Marc Zyngier
Date: Sun Jan 29 2017 - 10:34:26 EST
On Fri, Jan 27 2017 at 01:04:56 AM, Jintack Lim <jintack@xxxxxxxxxxxxxxx> wrote:
> Now that we maintain the EL1 physical timer register states of VMs,
> update the physical timer interrupt level along with the virtual one.
> Note that the emulated EL1 physical timer is not mapped to any hardware
> timer, so we call a proper vgic function.
> Signed-off-by: Jintack Lim <jintack@xxxxxxxxxxxxxxx>
> virt/kvm/arm/arch_timer.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 0f6e935..3b6bd50 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -180,6 +180,21 @@ static void kvm_timer_update_mapped_irq(struct kvm_vcpu *vcpu, bool new_level,
> +static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
> + struct arch_timer_context *timer)
> + int ret;
> + BUG_ON(!vgic_initialized(vcpu->kvm));
Although I've added my fair share of BUG_ON() in the code base, I've
since reconsidered my position. If we get in a situation where the vgic
is not initialized, maybe it would be better to just WARN_ON and return
early rather than killing the whole box. Thoughts?
> + timer->irq.level = new_level;
> + trace_kvm_timer_update_irq(vcpu->vcpu_id, timer->irq.irq,
> + timer->irq.level);
> + ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, timer->irq.irq,
> + 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).
> @@ -188,6 +203,7 @@ static int kvm_timer_update_state(struct kvm_vcpu *vcpu)
> struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
> + struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
> * If userspace modified the timer registers via SET_ONE_REG before
> @@ -201,6 +217,10 @@ static int kvm_timer_update_state(struct kvm_vcpu *vcpu)
> if (kvm_timer_should_fire(vcpu, vtimer) != vtimer->irq.level)
> kvm_timer_update_mapped_irq(vcpu, !vtimer->irq.level, vtimer);
> + /* The emulated EL1 physical timer irq is not mapped to hardware */
Maybe a slightly better comment would be saying that we're using a
purely virtual interrupt, unrelated to the hardware interrupt.
> + if (kvm_timer_should_fire(vcpu, ptimer) != ptimer->irq.level)
> + kvm_timer_update_irq(vcpu, !ptimer->irq.level, ptimer);
> return 0;
Otherwise looks good.
Jazz is not dead. It just smells funny.