[patch V2 60/67] KVM/arm/arm64/vgic-new: Convert to hotplug state machine

[Anna-Maria Gleixner]

From: Anna-Maria Gleixner <anna-ma...@linutronix.de>

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

Signed-off-by: Anna-Maria Gleixner <anna-ma...@linutronix.de>
Cc: Andre Przywara <andre.przyw...@arm.com>
Cc: Christoffer Dall <christoffer.d...@linaro.org>
Cc: Eric Auger <eric.au...@linaro.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Marc Zyngier <marc.zyng...@arm.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Radim Krcmar <rkrc...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: k...@vger.kernel.org
Cc: kvm...@lists.cs.columbia.edu
Cc: linux-arm-ker...@lists.infradead.org
---
 include/linux/cpuhotplug.h    |  1 +
 virt/kvm/arm/vgic/vgic-init.c | 31 +++++++++----------------------
 2 files changed, 10 insertions(+), 22 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 078bd22..822df54 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -52,6 +52,7 @@ enum cpuhp_state {
        CPUHP_AP_QCOM_TIMER_STARTING,
        CPUHP_AP_MIPS_GIC_TIMER_STARTING,
        CPUHP_AP_KVM_STARTING,
+       CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
        CPUHP_AP_KVM_ARM_VGIC_STARTING,
        CPUHP_AP_KVM_ARM_TIMER_STARTING,
        CPUHP_AP_ARM_XEN_STARTING,
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index a1442f7..2c7f0d5 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -353,32 +353,19 @@ out:
 
 /* GENERIC PROBE */
 
-static void vgic_init_maintenance_interrupt(void *info)
+static int vgic_init_cpu_starting(unsigned int cpu)
 {
        enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
+       return 0;
 }
 
-static int vgic_cpu_notify(struct notifier_block *self,
-                          unsigned long action, void *cpu)
-{
-       switch (action) {
-       case CPU_STARTING:
-       case CPU_STARTING_FROZEN:
-               vgic_init_maintenance_interrupt(NULL);
-               break;
-       case CPU_DYING:
-       case CPU_DYING_FROZEN:
-               disable_percpu_irq(kvm_vgic_global_state.maint_irq);
-               break;
-       }
 
-       return NOTIFY_OK;
+static int vgic_init_cpu_dying(unsigned int cpu)
+{
+       disable_percpu_irq(kvm_vgic_global_state.maint_irq);
+       return 0;
 }
 
-static struct notifier_block vgic_cpu_nb = {
-       .notifier_call = vgic_cpu_notify,
-};
-
 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 {
        /*
@@ -434,14 +421,14 @@ int kvm_vgic_hyp_init(void)
                return ret;
        }
 
-       ret = __register_cpu_notifier(&vgic_cpu_nb);
+       ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
+                               "AP_KVM_ARM_VGIC_INIT_STARTING",
+                               vgic_init_cpu_starting, vgic_init_cpu_dying);
        if (ret) {
                kvm_err("Cannot register vgic CPU notifier\n");
                goto out_free_irq;
        }
 
-       on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
-
        kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
        return 0;
 
-- 
2.8.1