[PATCH RT 06/32] KVM: arm/arm64: Let the timer expire in hardirq context on RT

Steven Rostedt
2020-01-17T17:43:22Z

From: Thomas Gleixner <tglx@linutronix.de>

[ Upstream commit 719cc080c914045a6e35787bf4dc3ba91cfd3efb ]

The timers are canceled from an preempt-notifier which is invoked with
disabled preemption which is not allowed on PREEMPT_RT.
The timer callback is short so in could be invoked in hard-IRQ context
on -RT.

Let the timer expire on hard-IRQ context even on -RT.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Tested-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
virt/kvm/arm/arch_timer.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 17cecc96f735..217d39f40393 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -67,7 +67,7 @@ static inline bool userspace_irqchip(struct kvm *kvm)
static void soft_timer_start(struct hrtimer *hrt, u64 ns)
{
hrtimer_start(hrt, ktime_add_ns(ktime_get(), ns),
- HRTIMER_MODE_ABS);
+ HRTIMER_MODE_ABS_HARD);
}

static void soft_timer_cancel(struct hrtimer *hrt, struct work_struct *work)
@@ -638,10 +638,10 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
vcpu_ptimer(vcpu)->cntvoff = 0;

INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
- hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
timer->bg_timer.function = kvm_bg_timer_expire;

- hrtimer_init(&timer->phys_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ hrtimer_init(&timer->phys_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
timer->phys_timer.function = kvm_phys_timer_expire;

vtimer->irq.irq = default_vtimer_irq.irq;
--
2.24.1