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x86/kvm: Convert to hotplug state machine

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Install the callbacks via the state machine. The online & down callbacks are
invoked on the target CPU so we can avoid using smp_call_function_single().
local_irq_disable() is used because smp_call_function_single() used to invoke
the function with interrupts disabled.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160818125731.27256-15-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Sebastian Andrzej Siewior 2016-08-18 14:57:29 +02:00 committed by Thomas Gleixner
parent e8483b578b
commit 9a20ea4b4c
1 changed files with 16 additions and 27 deletions
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43
arch/x86/kernel/kvm.c
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@ -423,12 +423,7 @@ static void __init kvm_smp_prepare_boot_cpu(void)
kvm_spinlock_init();
}
static void kvm_guest_cpu_online(void *dummy)
{
kvm_guest_cpu_init();
}
static void kvm_guest_cpu_offline(void *dummy)
static void kvm_guest_cpu_offline(void)
{
kvm_disable_steal_time();
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
@ -437,29 +432,21 @@ static void kvm_guest_cpu_offline(void *dummy)
apf_task_wake_all();
}
static int kvm_cpu_notify(struct notifier_block *self, unsigned long action,
void *hcpu)
static int kvm_cpu_online(unsigned int cpu)
{
int cpu = (unsigned long)hcpu;
switch (action) {
case CPU_ONLINE:
case CPU_DOWN_FAILED:
case CPU_ONLINE_FROZEN:
smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
break;
default:
break;
}
return NOTIFY_OK;
local_irq_disable();
kvm_guest_cpu_init();
local_irq_enable();
return 0;
}
static struct notifier_block kvm_cpu_notifier = {
.notifier_call = kvm_cpu_notify,
};
static int kvm_cpu_down_prepare(unsigned int cpu)
{
local_irq_disable();
kvm_guest_cpu_offline();
local_irq_enable();
return 0;
}
#endif
static void __init kvm_apf_trap_init(void)
@ -494,7 +481,9 @@ void __init kvm_guest_init(void)
#ifdef CONFIG_SMP
smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
register_cpu_notifier(&kvm_cpu_notifier);
if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
kvm_cpu_online, kvm_cpu_down_prepare) < 0)
pr_err("kvm_guest: Failed to install cpu hotplug callbacks\n");
#else
kvm_guest_cpu_init();
#endif