KVM: protect kvm_usage_count with its own spinlock
The VM list need not be protected by a raw spinlock. Separate the
two so that kvm_lock can be made non-raw.
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>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 426051d..eb94343 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -71,6 +71,7 @@
*/
DEFINE_RAW_SPINLOCK(kvm_lock);
+static DEFINE_RAW_SPINLOCK(kvm_count_lock);
LIST_HEAD(vm_list);
static cpumask_var_t cpus_hardware_enabled;
@@ -2683,10 +2684,10 @@
static void hardware_enable(void)
{
- raw_spin_lock(&kvm_lock);
+ raw_spin_lock(&kvm_count_lock);
if (kvm_usage_count)
hardware_enable_nolock(NULL);
- raw_spin_unlock(&kvm_lock);
+ raw_spin_unlock(&kvm_count_lock);
}
static void hardware_disable_nolock(void *junk)
@@ -2701,10 +2702,10 @@
static void hardware_disable(void)
{
- raw_spin_lock(&kvm_lock);
+ raw_spin_lock(&kvm_count_lock);
if (kvm_usage_count)
hardware_disable_nolock(NULL);
- raw_spin_unlock(&kvm_lock);
+ raw_spin_unlock(&kvm_count_lock);
}
static void hardware_disable_all_nolock(void)
@@ -2718,16 +2719,16 @@
static void hardware_disable_all(void)
{
- raw_spin_lock(&kvm_lock);
+ raw_spin_lock(&kvm_count_lock);
hardware_disable_all_nolock();
- raw_spin_unlock(&kvm_lock);
+ raw_spin_unlock(&kvm_count_lock);
}
static int hardware_enable_all(void)
{
int r = 0;
- raw_spin_lock(&kvm_lock);
+ raw_spin_lock(&kvm_count_lock);
kvm_usage_count++;
if (kvm_usage_count == 1) {
@@ -2740,7 +2741,7 @@
}
}
- raw_spin_unlock(&kvm_lock);
+ raw_spin_unlock(&kvm_count_lock);
return r;
}
@@ -3130,7 +3131,7 @@
static void kvm_resume(void)
{
if (kvm_usage_count) {
- WARN_ON(raw_spin_is_locked(&kvm_lock));
+ WARN_ON(raw_spin_is_locked(&kvm_count_lock));
hardware_enable_nolock(NULL);
}
}