From c85aa6dfae439c6d554cca102c7c894e8face68f Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Mon, 9 Aug 2021 11:05:20 +0200
Subject: [PATCH] virtio-devices: vhost_user: Kill threads upon migration
 completion

In order to prevent the vhost-user devices from reconnecting to the
backend after the migration has been successfully performed, we make
sure to kill the thread in charge of handling the reconnection
mechanism.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 virtio-devices/src/vhost_user/blk.rs | 19 +++++++++++++++++++
 virtio-devices/src/vhost_user/fs.rs  | 19 +++++++++++++++++++
 virtio-devices/src/vhost_user/net.rs | 19 +++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/virtio-devices/src/vhost_user/blk.rs b/virtio-devices/src/vhost_user/blk.rs
index 7e887deef..083226ac9 100644
--- a/virtio-devices/src/vhost_user/blk.rs
+++ b/virtio-devices/src/vhost_user/blk.rs
@@ -483,4 +483,23 @@ impl Migratable for Blk {
             Ok(MemoryRangeTable::default())
         }
     }
+
+    fn complete_migration(&mut self) -> std::result::Result<(), MigratableError> {
+        // Make sure the device thread is killed in order to prevent from
+        // reconnections to the socket.
+        if let Some(kill_evt) = self.common.kill_evt.take() {
+            kill_evt.write(1).map_err(|e| {
+                MigratableError::CompleteMigration(anyhow!(
+                    "Error killing vhost-user-blk thread: {:?}",
+                    e
+                ))
+            })?;
+        }
+
+        // Drop the vhost-user handler to avoid further calls to fail because
+        // the connection with the backend has been closed.
+        self.vu = None;
+
+        Ok(())
+    }
 }
diff --git a/virtio-devices/src/vhost_user/fs.rs b/virtio-devices/src/vhost_user/fs.rs
index 93c8603cb..3aa533f66 100644
--- a/virtio-devices/src/vhost_user/fs.rs
+++ b/virtio-devices/src/vhost_user/fs.rs
@@ -763,4 +763,23 @@ impl Migratable for Fs {
             Ok(MemoryRangeTable::default())
         }
     }
+
+    fn complete_migration(&mut self) -> std::result::Result<(), MigratableError> {
+        // Make sure the device thread is killed in order to prevent from
+        // reconnections to the socket.
+        if let Some(kill_evt) = self.common.kill_evt.take() {
+            kill_evt.write(1).map_err(|e| {
+                MigratableError::CompleteMigration(anyhow!(
+                    "Error killing vhost-user-fs threads: {:?}",
+                    e
+                ))
+            })?;
+        }
+
+        // Drop the vhost-user handler to avoid further calls to fail because
+        // the connection with the backend has been closed.
+        self.vu = None;
+
+        Ok(())
+    }
 }
diff --git a/virtio-devices/src/vhost_user/net.rs b/virtio-devices/src/vhost_user/net.rs
index 78eba4e0a..33d3f3e9b 100644
--- a/virtio-devices/src/vhost_user/net.rs
+++ b/virtio-devices/src/vhost_user/net.rs
@@ -569,4 +569,23 @@ impl Migratable for Net {
             Ok(MemoryRangeTable::default())
         }
     }
+
+    fn complete_migration(&mut self) -> std::result::Result<(), MigratableError> {
+        // Make sure the device thread is killed in order to prevent from
+        // reconnections to the socket.
+        if let Some(kill_evt) = self.common.kill_evt.take() {
+            kill_evt.write(1).map_err(|e| {
+                MigratableError::CompleteMigration(anyhow!(
+                    "Error killing vhost-user-net threads: {:?}",
+                    e
+                ))
+            })?;
+        }
+
+        // Drop the vhost-user handler to avoid further calls to fail because
+        // the connection with the backend has been closed.
+        self.vu = None;
+
+        Ok(())
+    }
 }