From 1b6c016818a562aaea22b1a1b05b15c796b0c2f0 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Thu, 24 May 2007 13:03:52 +0300 Subject: KVM: Keep track of which cpus have virtualization enabled By keeping track of which cpus have virtualization enabled, we prevent double-enable or double-disable during hotplug, which is a very fatal oops. Signed-off-by: Avi Kivity --- drivers/kvm/kvm_main.c | 45 +++++++++++++++++++++++++++++++++------------ 1 file changed, 33 insertions(+), 12 deletions(-) (limited to 'drivers/kvm') diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index ea027190a65..3226ad4bce7 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -50,8 +50,12 @@ MODULE_LICENSE("GPL"); static DEFINE_SPINLOCK(kvm_lock); static LIST_HEAD(vm_list); +static cpumask_t cpus_hardware_enabled; + struct kvm_arch_ops *kvm_arch_ops; +static void hardware_disable(void *ignored); + #define STAT_OFFSET(x) offsetof(struct kvm_vcpu, stat.x) static struct kvm_stats_debugfs_item { @@ -2930,7 +2934,7 @@ static int kvm_reboot(struct notifier_block *notifier, unsigned long val, * in vmx root mode. */ printk(KERN_INFO "kvm: exiting hardware virtualization\n"); - on_each_cpu(kvm_arch_ops->hardware_disable, NULL, 0, 1); + on_each_cpu(hardware_disable, NULL, 0, 1); } return NOTIFY_OK; } @@ -2973,6 +2977,27 @@ static void decache_vcpus_on_cpu(int cpu) spin_unlock(&kvm_lock); } +static void hardware_enable(void *junk) +{ + int cpu = raw_smp_processor_id(); + + if (cpu_isset(cpu, cpus_hardware_enabled)) + return; + cpu_set(cpu, cpus_hardware_enabled); + kvm_arch_ops->hardware_enable(NULL); +} + +static void hardware_disable(void *junk) +{ + int cpu = raw_smp_processor_id(); + + if (!cpu_isset(cpu, cpus_hardware_enabled)) + return; + cpu_clear(cpu, cpus_hardware_enabled); + decache_vcpus_on_cpu(cpu); + kvm_arch_ops->hardware_disable(NULL); +} + static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, void *v) { @@ -2985,16 +3010,13 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, case CPU_UP_CANCELED_FROZEN: printk(KERN_INFO "kvm: disabling virtualization on CPU%d\n", cpu); - decache_vcpus_on_cpu(cpu); - smp_call_function_single(cpu, kvm_arch_ops->hardware_disable, - NULL, 0, 1); + smp_call_function_single(cpu, hardware_disable, NULL, 0, 1); break; case CPU_ONLINE: case CPU_ONLINE_FROZEN: printk(KERN_INFO "kvm: enabling virtualization on CPU%d\n", cpu); - smp_call_function_single(cpu, kvm_arch_ops->hardware_enable, - NULL, 0, 1); + smp_call_function_single(cpu, hardware_enable, NULL, 0, 1); break; } return NOTIFY_OK; @@ -3088,14 +3110,13 @@ static void kvm_exit_debug(void) static int kvm_suspend(struct sys_device *dev, pm_message_t state) { - decache_vcpus_on_cpu(raw_smp_processor_id()); - on_each_cpu(kvm_arch_ops->hardware_disable, NULL, 0, 1); + on_each_cpu(hardware_disable, NULL, 0, 0); return 0; } static int kvm_resume(struct sys_device *dev) { - on_each_cpu(kvm_arch_ops->hardware_enable, NULL, 0, 1); + on_each_cpu(hardware_disable, NULL, 0, 0); return 0; } @@ -3136,7 +3157,7 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module) if (r < 0) goto out; - on_each_cpu(kvm_arch_ops->hardware_enable, NULL, 0, 1); + on_each_cpu(hardware_enable, NULL, 0, 1); r = register_cpu_notifier(&kvm_cpu_notifier); if (r) goto out_free_1; @@ -3168,7 +3189,7 @@ out_free_2: unregister_reboot_notifier(&kvm_reboot_notifier); unregister_cpu_notifier(&kvm_cpu_notifier); out_free_1: - on_each_cpu(kvm_arch_ops->hardware_disable, NULL, 0, 1); + on_each_cpu(hardware_disable, NULL, 0, 1); kvm_arch_ops->hardware_unsetup(); out: kvm_arch_ops = NULL; @@ -3182,7 +3203,7 @@ void kvm_exit_arch(void) sysdev_class_unregister(&kvm_sysdev_class); unregister_reboot_notifier(&kvm_reboot_notifier); unregister_cpu_notifier(&kvm_cpu_notifier); - on_each_cpu(kvm_arch_ops->hardware_disable, NULL, 0, 1); + on_each_cpu(hardware_disable, NULL, 0, 1); kvm_arch_ops->hardware_unsetup(); kvm_arch_ops = NULL; } -- cgit v1.2.3