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Commit 8c18b2d2 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

virt: Convert kvm hotplug to state machine 



Install the callbacks via the state machine. The core won't invoke the
callbacks on already online CPUs.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153335.886159080@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7d88eb69

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ enum cpuhp_state { 
	CPUHP_AP_PERF_XTENSA_STARTING,

	CPUHP_AP_ARM_VFP_STARTING,

	CPUHP_AP_PERF_ARM_STARTING,

	CPUHP_AP_KVM_STARTING,

	CPUHP_AP_NOTIFY_STARTING,

	CPUHP_AP_ONLINE,

	CPUHP_TEARDOWN_CPU,

virt/kvm/kvm_main.c

+8 −24
Original line number Diff line number Diff line
@@ -3144,12 +3144,13 @@ static void hardware_enable_nolock(void *junk) 
	}

}



static void hardware_enable(void)

static int kvm_starting_cpu(unsigned int cpu)

{

	raw_spin_lock(&kvm_count_lock);

	if (kvm_usage_count)

		hardware_enable_nolock(NULL);

	raw_spin_unlock(&kvm_count_lock);

	return 0;

}



static void hardware_disable_nolock(void *junk)
@@ -3162,12 +3163,13 @@ static void hardware_disable_nolock(void *junk) 
	kvm_arch_hardware_disable();

}



static void hardware_disable(void)

static int kvm_dying_cpu(unsigned int cpu)

{

	raw_spin_lock(&kvm_count_lock);

	if (kvm_usage_count)

		hardware_disable_nolock(NULL);

	raw_spin_unlock(&kvm_count_lock);

	return 0;

}



static void hardware_disable_all_nolock(void)
@@ -3208,21 +3210,6 @@ static int hardware_enable_all(void) 
	return r;

}



static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,

			   void *v)

{

	val &= ~CPU_TASKS_FROZEN;

	switch (val) {

	case CPU_DYING:

		hardware_disable();

		break;

	case CPU_STARTING:

		hardware_enable();

		break;

	}

	return NOTIFY_OK;

}



static int kvm_reboot(struct notifier_block *notifier, unsigned long val,

		      void *v)

{
@@ -3489,10 +3476,6 @@ int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, 
	return r;

}



static struct notifier_block kvm_cpu_notifier = {

	.notifier_call = kvm_cpu_hotplug,

};



static int kvm_debugfs_open(struct inode *inode, struct file *file,

			   int (*get)(void *, u64 *), int (*set)(void *, u64),

			   const char *fmt)
@@ -3743,7 +3726,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, 
			goto out_free_1;

	}



	r = register_cpu_notifier(&kvm_cpu_notifier);

	r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_STARTING, "AP_KVM_STARTING",

				      kvm_starting_cpu, kvm_dying_cpu);

	if (r)

		goto out_free_2;

	register_reboot_notifier(&kvm_reboot_notifier);
@@ -3797,7 +3781,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, 
	kmem_cache_destroy(kvm_vcpu_cache);

out_free_3:

	unregister_reboot_notifier(&kvm_reboot_notifier);

	unregister_cpu_notifier(&kvm_cpu_notifier);

	cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);

out_free_2:

out_free_1:

	kvm_arch_hardware_unsetup();
@@ -3820,7 +3804,7 @@ void kvm_exit(void) 
	kvm_async_pf_deinit();

	unregister_syscore_ops(&kvm_syscore_ops);

	unregister_reboot_notifier(&kvm_reboot_notifier);

	unregister_cpu_notifier(&kvm_cpu_notifier);

	cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);

	on_each_cpu(hardware_disable_nolock, NULL, 1);

	kvm_arch_hardware_unsetup();

	kvm_arch_exit();