Commit-ID: 9a20ea4b4c34764416e935090d6e5ede02d1bada
Gitweb: http://git.kernel.org/tip/9a20ea4b4c34764416e935090d6e5ede02d1bada
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Thu, 18 Aug 2016 14:57:29 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 6 Sep 2016 18:30:25 +0200
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 <bigeasy@xxxxxxxxxxxxx>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: rt@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20160818125731.27256-15-bigeasy@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
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 1726c4c..1f431f3 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
--
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