diff options
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ee1005cb99e17..2d6203ecab883 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -5167,15 +5167,26 @@ static void hardware_disable_all_nolock(void) static void hardware_disable_all(void) { + cpus_read_lock(); raw_spin_lock(&kvm_count_lock); hardware_disable_all_nolock(); raw_spin_unlock(&kvm_count_lock); + cpus_read_unlock(); } static int hardware_enable_all(void) { int r = 0; + /* + * When onlining a CPU, cpu_online_mask is set before kvm_online_cpu() + * is called, and so on_each_cpu() between them includes the CPU that + * is being onlined. As a result, hardware_enable_nolock() may get + * invoked before kvm_online_cpu(), which also enables hardware if the + * usage count is non-zero. Disable CPU hotplug to avoid attempting to + * enable hardware multiple times. + */ + cpus_read_lock(); raw_spin_lock(&kvm_count_lock); kvm_usage_count++; @@ -5190,6 +5201,7 @@ static int hardware_enable_all(void) } raw_spin_unlock(&kvm_count_lock); + cpus_read_unlock(); return r; } |