diff options
| -rw-r--r-- | pkg/sentry/platform/kvm/machine.go | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go index e7092a756..d67563958 100644 --- a/pkg/sentry/platform/kvm/machine.go +++ b/pkg/sentry/platform/kvm/machine.go @@ -519,15 +519,21 @@ func (c *vCPU) lock() { // //go:nosplit func (c *vCPU) unlock() { - if atomic.CompareAndSwapUint32(&c.state, vCPUUser|vCPUGuest, vCPUGuest) { + origState := atomicbitops.CompareAndSwapUint32(&c.state, vCPUUser|vCPUGuest, vCPUGuest) + if origState == vCPUUser|vCPUGuest { // Happy path: no exits are forced, and we can continue // executing on our merry way with a single atomic access. return } // Clear the lock. - origState := atomic.LoadUint32(&c.state) - atomicbitops.AndUint32(&c.state, ^vCPUUser) + for { + state := atomicbitops.CompareAndSwapUint32(&c.state, origState, origState&^vCPUUser) + if state == origState { + break + } + origState = state + } switch origState { case vCPUUser: // Normal state. |