diff options
Diffstat (limited to 'virt/kvm/kvm_main.c')
| -rw-r--r-- | virt/kvm/kvm_main.c | 36 |
1 files changed, 24 insertions, 12 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0c3b9d6fa1b1..f6caee790dc8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -100,7 +100,6 @@ EXPORT_SYMBOL_GPL(halt_poll_ns_shrink); */ DEFINE_MUTEX(kvm_lock); -static DEFINE_RAW_SPINLOCK(kvm_count_lock); LIST_HEAD(vm_list); static cpumask_var_t cpus_hardware_enabled; @@ -5123,17 +5122,18 @@ static int kvm_online_cpu(unsigned int cpu) * be enabled. Otherwise running VMs would encounter unrecoverable * errors when scheduled to this CPU. */ - raw_spin_lock(&kvm_count_lock); + mutex_lock(&kvm_lock); if (kvm_usage_count) { WARN_ON_ONCE(atomic_read(&hardware_enable_failed)); hardware_enable_nolock(NULL); + if (atomic_read(&hardware_enable_failed)) { atomic_set(&hardware_enable_failed, 0); ret = -EIO; } } - raw_spin_unlock(&kvm_count_lock); + mutex_unlock(&kvm_lock); return ret; } @@ -5149,10 +5149,10 @@ static void hardware_disable_nolock(void *junk) static int kvm_offline_cpu(unsigned int cpu) { - raw_spin_lock(&kvm_count_lock); + mutex_lock(&kvm_lock); if (kvm_usage_count) hardware_disable_nolock(NULL); - raw_spin_unlock(&kvm_count_lock); + mutex_unlock(&kvm_lock); return 0; } @@ -5168,9 +5168,9 @@ static void hardware_disable_all_nolock(void) static void hardware_disable_all(void) { cpus_read_lock(); - raw_spin_lock(&kvm_count_lock); + mutex_lock(&kvm_lock); hardware_disable_all_nolock(); - raw_spin_unlock(&kvm_count_lock); + mutex_unlock(&kvm_lock); cpus_read_unlock(); } @@ -5187,7 +5187,7 @@ static int hardware_enable_all(void) * enable hardware multiple times. */ cpus_read_lock(); - raw_spin_lock(&kvm_count_lock); + mutex_lock(&kvm_lock); kvm_usage_count++; if (kvm_usage_count == 1) { @@ -5200,7 +5200,7 @@ static int hardware_enable_all(void) } } - raw_spin_unlock(&kvm_count_lock); + mutex_unlock(&kvm_lock); cpus_read_unlock(); return r; @@ -5806,6 +5806,17 @@ static void kvm_init_debug(void) static int kvm_suspend(void) { + /* + * Secondary CPUs and CPU hotplug are disabled across the suspend/resume + * callbacks, i.e. no need to acquire kvm_lock to ensure the usage count + * is stable. Assert that kvm_lock is not held to ensure the system + * isn't suspended while KVM is enabling hardware. Hardware enabling + * can be preempted, but the task cannot be frozen until it has dropped + * all locks (userspace tasks are frozen via a fake signal). + */ + lockdep_assert_not_held(&kvm_lock); + lockdep_assert_irqs_disabled(); + if (kvm_usage_count) hardware_disable_nolock(NULL); return 0; @@ -5813,10 +5824,11 @@ static int kvm_suspend(void) static void kvm_resume(void) { - if (kvm_usage_count) { - lockdep_assert_not_held(&kvm_count_lock); + lockdep_assert_not_held(&kvm_lock); + lockdep_assert_irqs_disabled(); + + if (kvm_usage_count) hardware_enable_nolock(NULL); - } } static struct syscore_ops kvm_syscore_ops = { |