[shimV2] bind GCS/host hvsock listeners before starting the UVM#2723
Merged
rawahars merged 3 commits intomicrosoft:mainfrom May 7, 2026
Merged
[shimV2] bind GCS/host hvsock listeners before starting the UVM#2723rawahars merged 3 commits intomicrosoft:mainfrom
rawahars merged 3 commits intomicrosoft:mainfrom
Conversation
- Split guestmanager.Guest.CreateConnection into PrepareConnection (binds the GCS hvsock listener) + CreateConnection (accepts and runs the handshake) so the host is listening before the guest dials. - Controller.StartVM now calls PrepareConnection and the entropy/logging listener setup before uvm.Start, and propagates their errors. - LCOW/WCOW setupEntropyListener/setupLoggingListener now bind the hvsock listener synchronously and only Accept inside the goroutine; return error instead of swallowing/logging it. - CloseConnection also closes a prepared-but-unaccepted listener. - vmmanager.AcceptConnection: buffer the result channel to avoid a goroutine leak and close the listener on context cancellation. Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
jterry75
reviewed
May 7, 2026
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
jterry75
approved these changes
May 7, 2026
rawahars
added this to the
[shim V2] Adds the V2 shim for Linux containers on Windows milestone
jiechen0826
approved these changes
May 7, 2026
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Summary
Refactors VM startup and GCS connection setup to eliminate races between host listener creation and in-VM guest dials.
Changes
Two-phase GCS connection: Split setup intoPrepareConnection(binds host hvsock listener before VM start) andCreateConnection(accepts the dial after VM start). Guarantees the host is listening when the guest connects. Both calls are idempotent for the same service ID.Synchronous listener setup:setupEntropyListenerandsetupLoggingListener(LCOW + WCOW) are now synchronous and return errors, so listener failures are caught before VM boot instead of in background goroutines.Resource cleanup: vsock listeners are reliably closed on both success and error paths to prevent leaks.CloseConnectiontears down both the active connection and any pending listener.AcceptConnection hardening: Uses a buffered result channel and closes the listener on context cancellation to avoid goroutine leaks.Why
Previously, listeners were set up asynchronously and the GCS handshake could race the guest's dial, leading to flaky startup failures. The new flow makes ordering explicit and errors fail fast.
Testing
Existing LCOW/WCOW startup paths exercised; no behavior change on the happy path.