diff options
Diffstat (limited to 'pkg/sentry/platform/kvm/machine.go')
| -rw-r--r-- | pkg/sentry/platform/kvm/machine.go | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go index 455e2bd20..61ed24d01 100644 --- a/pkg/sentry/platform/kvm/machine.go +++ b/pkg/sentry/platform/kvm/machine.go @@ -103,8 +103,11 @@ type vCPU struct { // tid is the last set tid. tid uint64 - // switches is a count of world switches (informational only). - switches uint32 + // userExits is the count of user exits. + userExits uint64 + + // guestExits is the count of guest to host world switches. + guestExits uint64 // faults is a count of world faults (informational only). faults uint32 @@ -127,6 +130,7 @@ type vCPU struct { // vCPUArchState is the architecture-specific state. vCPUArchState + // dieState holds state related to vCPU death. dieState dieState } @@ -540,6 +544,8 @@ var pid = syscall.Getpid() // // This effectively unwinds the state machine. func (c *vCPU) bounce(forceGuestExit bool) { + origGuestExits := atomic.LoadUint64(&c.guestExits) + origUserExits := atomic.LoadUint64(&c.userExits) for { switch state := atomic.LoadUint32(&c.state); state { case vCPUReady, vCPUWaiter: @@ -595,6 +601,14 @@ func (c *vCPU) bounce(forceGuestExit bool) { // Should not happen: the above is exhaustive. panic("invalid state") } + + // Check if we've missed the state transition, but + // we can safely return at this point in time. + newGuestExits := atomic.LoadUint64(&c.guestExits) + newUserExits := atomic.LoadUint64(&c.userExits) + if newUserExits != origUserExits && (!forceGuestExit || newGuestExits != origGuestExits) { + return + } } } |