devices: ioapic: Implement the Snapshottable trait

Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>

devices/Cargo.toml

@@ -4,14 +4,19 @@ version = "0.1.0"
 authors = ["The Chromium OS Authors"]
 
 [dependencies]
+anyhow = "1.0"
 bitflags = ">=1.2.1"
 byteorder = "1.3.4"
 epoll = ">=4.0.1"
 libc = "0.2.68"
 log = "0.4.8"
+serde = {version = ">=1.0.27", features = ["rc"] }
+serde_derive = ">=1.0.27"
+serde_json = ">=1.0.9"
 vm-device = { path = "../vm-device" }
 acpi_tables = { path = "../acpi_tables", optional = true }
 vm-memory = "0.2.0"
+vm-migration = { path = "../vm-migration" }
 vmm-sys-util = ">=0.3.1"
 
 [dev-dependencies]