On 11/07/2016 14:28, Anna-Maria Gleixner wrote:
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> Install the callbacks via the state machine. The core won't invoke the
> callbacks on already online CPUs.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> Cc: Gleb Natapov <gleb@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: kvm@xxxxxxxxxxxxxxx
> Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
>
> ---
> include/linux/cpuhotplug.h | 1 +
> virt/kvm/kvm_main.c | 32 ++++++++------------------------
> 2 files changed, 9 insertions(+), 24 deletions(-)
>
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -37,6 +37,7 @@ 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,
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3144,12 +3144,13 @@ static void hardware_enable_nolock(void
> }
> }
>
> -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
> 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
> 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
> 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
> 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();
>
>
> --
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>
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
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