It is quite subtle why we mask the timer on behalf of the guest when
then guest has programmed the timer and it fires and is handled on the
host.
Add a comment to that effect.
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
---
virt/kvm/arm/arch_timer.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index c2e1ef4..8168437 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -63,6 +63,12 @@ static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+ /*
+ * Mask the virtual timer, because otherwise, the guest would never
+ * execute its interrupt handler because the virtual timer interrupt
+ * would continously preempt guest execution as the hardware interrupt
+ * traps to Hyp mode.
+ */
timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
timer->irq->irq,
--
1.7.10.4
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
