Merge branch 'main' into 4534

CHANGELOG.md

@@ -18,6 +18,11 @@ and this project adheres to
 
 ### Fixed
 
+- [#4796](https://github.com/firecracker-microvm/firecracker/pull/4796): Fixed
+  Vsock not notifying guest about `TRANSPORT_RESET_EVENT` event after snapshot
+  restore. This resulted in guest waiting indefinitely on a connection which was
+  reset during snapshot creation.
+
 ## \[1.9.0\]
 
 ### Added
@@ -812,7 +817,9 @@ and this project adheres to
   `--show-level` and `--show-log-origin` that can be used for configuring the
   Logger when starting the process. When using this method for configuration,
   only `--log-path` is mandatory.
-- Added a [guide](docs/devctr-image.md) for updating the dev container image.
+- Added a
+  [guide](https://github.com/firecracker-microvm/firecracker/blob/v0.22.0/docs/devctr-image.md)
+  for updating the dev container image.
 - Added a new API call, `PUT /mmds/config`, for configuring the `MMDS` with a
   custom valid link-local IPv4 address.
 - Added experimental JSON response format support for MMDS guest applications

src/vmm/src/device_manager/mmio.rs

@@ -34,7 +34,7 @@ use crate::devices::virtio::device::VirtioDevice;
 use crate::devices::virtio::mmio::MmioTransport;
 use crate::devices::virtio::net::Net;
 use crate::devices::virtio::rng::Entropy;
-use crate::devices::virtio::vsock::TYPE_VSOCK;
+use crate::devices::virtio::vsock::{Vsock, VsockUnixBackend, TYPE_VSOCK};
 use crate::devices::virtio::{TYPE_BALLOON, TYPE_BLOCK, TYPE_NET, TYPE_RNG};
 use crate::devices::BusDevice;
 #[cfg(target_arch = "x86_64")]
@@ -489,6 +489,16 @@ impl MMIODeviceManager {
                         // so for Vsock we don't support connection persistence through snapshot.
                         // Any in-flight packets or events are simply lost.
                         // Vsock is restored 'empty'.
+                        // The only reason we still `kick` it is to make guest process
+                        // `TRANSPORT_RESET_EVENT` event we sent during snapshot creation.
+                        let vsock = virtio
+                            .as_mut_any()
+                            .downcast_mut::<Vsock<VsockUnixBackend>>()
+                            .unwrap();
+                        if vsock.is_activated() {
+                            info!("kick vsock {id}.");
+                            vsock.signal_used_queue().unwrap();
+                        }
                     }
                     TYPE_RNG => {
                         let entropy = virtio.as_mut_any().downcast_mut::<Entropy>().unwrap();