diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2013-09-10 12:58:35 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2013-09-30 09:21:46 +0200 |
| commit | 4a937f96f3a29c58b7edd349d2e4dfac371efdf2 (patch) | |
| tree | 67471522814264ea197e724a1ca09a424bdbba6c | |
| parent | 4fa92fb25ae5a2d79d872ab54df511c831b1f363 (diff) | |
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>
| -rw-r--r-- | Documentation/virtual/kvm/locking.txt | 6 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 19 |
2 files changed, 15 insertions, 10 deletions
diff --git a/Documentation/virtual/kvm/locking.txt b/Documentation/virtual/kvm/locking.txt index a9f366e73c8e..ba9e1c2150c2 100644 --- a/Documentation/virtual/kvm/locking.txt +++ b/Documentation/virtual/kvm/locking.txt @@ -135,7 +135,11 @@ Name: kvm_lock Type: raw_spinlock Arch: any Protects: - vm_list - - hardware virtualization enable/disable + +Name: kvm_count_lock +Type: raw_spinlock_t +Arch: any +Protects: - hardware virtualization enable/disable Comment: 'raw' because hardware enabling/disabling must be atomic /wrt migration. diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 426051d66173..eb94343c2ed2 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -71,6 +71,7 @@ MODULE_LICENSE("GPL"); */ 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_nolock(void *junk) 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_nolock(void *junk) 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_nolock(void) 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 @@ static int hardware_enable_all(void) } } - raw_spin_unlock(&kvm_lock); + raw_spin_unlock(&kvm_count_lock); return r; } @@ -3130,7 +3131,7 @@ static int kvm_suspend(void) 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); } } |