From 9a20ea4b4c34764416e935090d6e5ede02d1bada Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 18 Aug 2016 14:57:29 +0200 Subject: [PATCH] x86/kvm: Convert to hotplug state machine 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 Reviewed-by: Paolo Bonzini Cc: kvm@vger.kernel.org Cc: Peter Zijlstra Cc: Gleb Natapov Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160818125731.27256-15-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/kernel/kvm.c | 43 ++++++++++++++++--------------------------- 1 file changed, 16 insertions(+), 27 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 1726c4c12336..1f431f362dd5 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -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 -- 2.34.1