[patch V2 45/67] arm/kvm/arch_timer: Convert to hotplug state machine

From: Anna-Maria Gleixner
Date: Wed Jul 13 2016 - 13:29:22 EST


From: Richard Cochran <rcochran@xxxxxxxxxxxxx>

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Richard Cochran <rcochran@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Radim Krcmar <rkrcmar@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
---
include/linux/cpuhotplug.h | 1 +
virt/kvm/arm/arch_timer.c | 35 +++++++++++------------------------
2 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 80c15ce..0a36e61 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -44,6 +44,7 @@ enum cpuhp_state {
CPUHP_AP_MIPS_GIC_TIMER_STARTING,
CPUHP_AP_KVM_STARTING,
CPUHP_AP_KVM_ARM_VGIC_STARTING,
+ CPUHP_AP_KVM_ARM_TIMER_STARTING,
CPUHP_AP_LEDTRIG_STARTING,
CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index e2d5b6f..4fde8c7 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -405,26 +405,17 @@ u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
return (u64)-1;
}

-static int kvm_timer_cpu_notify(struct notifier_block *self,
- unsigned long action, void *cpu)
+static int kvm_timer_starting_cpu(unsigned int cpu)
{
- switch (action) {
- case CPU_STARTING:
- case CPU_STARTING_FROZEN:
- kvm_timer_init_interrupt(NULL);
- break;
- case CPU_DYING:
- case CPU_DYING_FROZEN:
- disable_percpu_irq(host_vtimer_irq);
- break;
- }
-
- return NOTIFY_OK;
+ kvm_timer_init_interrupt(NULL);
+ return 0;
}

-static struct notifier_block kvm_timer_cpu_nb = {
- .notifier_call = kvm_timer_cpu_notify,
-};
+static int kvm_timer_dying_cpu(unsigned int cpu)
+{
+ disable_percpu_irq(host_vtimer_irq);
+ return 0;
+}

int kvm_timer_hyp_init(void)
{
@@ -449,12 +440,6 @@ int kvm_timer_hyp_init(void)
goto out;
}

- err = __register_cpu_notifier(&kvm_timer_cpu_nb);
- if (err) {
- kvm_err("Cannot register timer CPU notifier\n");
- goto out_free;
- }
-
wqueue = create_singlethread_workqueue("kvm_arch_timer");
if (!wqueue) {
err = -ENOMEM;
@@ -462,8 +447,10 @@ int kvm_timer_hyp_init(void)
}

kvm_info("virtual timer IRQ%d\n", host_vtimer_irq);
- on_each_cpu(kvm_timer_init_interrupt, NULL, 1);

+ cpuhp_setup_state(CPUHP_AP_KVM_ARM_TIMER_STARTING,
+ "AP_KVM_ARM_TIMER_STARTING", kvm_timer_starting_cpu,
+ kvm_timer_dying_cpu);
goto out;
out_free:
free_percpu_irq(host_vtimer_irq, kvm_get_running_vcpus());
--
2.8.1