Trait InterruptHandle 

pub trait InterruptHandle:
    Debug
    + Send
    + Sync {
    // Required methods
    fn kill(&self) -> bool;
    fn dropped(&self) -> bool;
}

A trait for handling interrupts to a sandbox’s vcpu (public API)

Required Methods

fn kill(&self) -> bool

Interrupt the corresponding sandbox from running.

This method attempts to cancel a currently executing guest function call by sending a signal to the VCPU thread. It uses generation tracking and call_active flag to ensure the interruption is safe and precise.

Behavior

• Guest function running: If called while a guest function is executing (VCPU running or in a host function call), this stamps the current generation into cancel_requested and sends a signal to interrupt the VCPU. Returns true.

• No active call: If called when no guest function call is in progress (call_active=false), this has no effect and returns false. This prevents “kill-in-advance” where kill() is called before a guest function starts.

• During host function: If the guest call is currently executing a host function (VCPU not running but call_active=true), this stamps cancel_requested. When the host function returns and attempts to re-enter the guest, the cancellation will be detected and the call will abort. Returns true.

Generation Tracking

The method stamps the current generation number along with the cancellation request. This ensures that:

• Stale signals from previous calls are ignored (generation mismatch)
• Only the intended guest function call is affected
• Multiple rapid kill() calls on the same generation are idempotent

Blocking Behavior

This function will block while attempting to deliver the signal to the VCPU thread, retrying until either:

• The signal is successfully delivered (VCPU transitions from running to not running)
• The VCPU stops running for another reason (e.g., call completes normally)

Returns

• true: Cancellation request was stamped (kill will take effect)
• false: No active call, cancellation request was not stamped (no effect)

Note

To reliably interrupt a guest call, ensure kill() is called while the guest function is actually executing. Calling kill() before call_guest_function() will have no effect.

fn dropped(&self) -> bool

Check if the corresponding VM has been dropped.

Implementors