fix: Free page hinting kick on restore

Move the reset logic for post restore hinting to the kick method. This
will reset the command back to DONE to ensure the memory is freed on
restore. Previously this was done on activate which meant is was
triggered on boot creating an uneeded interrupt.

Signed-off-by: Jack Thomson <[email protected]>

Author: JackThomson2

src/vmm/src/devices/virtio/balloon/device.rs

@@ -946,12 +946,6 @@ impl VirtioDevice for Balloon {
             self.update_timer_state();
         }
 
-        // On activate ensure hint cmd is reset to FREE_PAGE_HINT_DONE
-        if self.is_activated() && self.free_page_hinting() {
-            self.update_free_page_hint_cmd(FREE_PAGE_HINT_DONE)
-                .map_err(|_| ActivateError::EventFd)?;
-        }
-
         Ok(())
     }
 
@@ -965,6 +959,10 @@ impl VirtioDevice for Balloon {
         // Stats queue doesn't need kicking as it is notified via a `timer_fd`.
         if self.is_activated() {
             info!("kick balloon {}.", self.id());
+            if self.free_page_hinting() {
+                // On restore we reset back to DONE to ensure everythign is freed
+                self.update_free_page_hint_cmd(FREE_PAGE_HINT_DONE);
+            }
             self.process_virtio_queues();
         }
     }