KVM: cleanup (physical) CPU hotplug

Remove the useless argument, and do not do anything if there are no
VMs running at the time of the hotplug.

Cc: kvm@vger.kernel.org
Cc: gleb@redhat.com
Cc: jan.kiszka@siemens.com
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 4fa92fb25ae5a2d79d872ab54df511c831b1f363)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fcbcf5312f933ea98d67e1802d4058cd05992fa2..7103b989ba54a4749102b300e97a3a62ad8b61df 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2681,10 +2681,11 @@ static void hardware_enable_nolock(void *junk)
        }
 }
 
-static void hardware_enable(void *junk)
+static void hardware_enable(void)
 {
        raw_spin_lock(&kvm_lock);
-       hardware_enable_nolock(junk);
+       if (kvm_usage_count)
+               hardware_enable_nolock(NULL);
        raw_spin_unlock(&kvm_lock);
 }
 
@@ -2698,10 +2699,11 @@ static void hardware_disable_nolock(void *junk)
        kvm_arch_hardware_disable(NULL);
 }
 
-static void hardware_disable(void *junk)
+static void hardware_disable(void)
 {
        raw_spin_lock(&kvm_lock);
-       hardware_disable_nolock(junk);
+       if (kvm_usage_count)
+               hardware_disable_nolock(NULL);
        raw_spin_unlock(&kvm_lock);
 }
 
@@ -2748,20 +2750,17 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
 {
        int cpu = (long)v;
 
-       if (!kvm_usage_count)
-               return NOTIFY_OK;
-
        val &= ~CPU_TASKS_FROZEN;
        switch (val) {
        case CPU_DYING:
                printk(KERN_INFO "kvm: disabling virtualization on CPU%d\n",
                       cpu);
-               hardware_disable(NULL);
+               hardware_disable();
                break;
        case CPU_STARTING:
                printk(KERN_INFO "kvm: enabling virtualization on CPU%d\n",
                       cpu);
-               hardware_enable(NULL);
+               hardware_enable();
                break;
        }
        return NOTIFY_OK;