vmm,devices: Change Gic snapshot and restore path

The snapshot and restore of AArch64 Gic was done in Vm. Now it is moved
to DeviceManager.

The benefit is that the restore can be done while the Gic is created in
DeviceManager.

While the moving of state data from Vm snapshot to DeviceManager
snapshot breaks the compatability of migration from older versions.

Signed-off-by: Michael Zhao <michael.zhao@arm.com>

devices/src/gic.rs

@@ -8,7 +8,7 @@ use anyhow::anyhow;
 use arch::layout;
 use hypervisor::{
     arch::aarch64::gic::{Vgic, VgicConfig},
-    CpuState,
+    CpuState, GicState,
 };
 use std::result;
 use std::sync::{Arc, Mutex};
@@ -25,6 +25,7 @@ type Result<T> = result::Result<T, Error>;
 // Reserve 32 IRQs for legacy devices.
 pub const IRQ_LEGACY_BASE: usize = layout::IRQ_BASE as usize;
 pub const IRQ_LEGACY_COUNT: usize = 32;
+pub const GIC_SNAPSHOT_ID: &str = "gic-v3-its";
 
 // Gic (Generic Interupt Controller) struct provides all the functionality of a
 // GIC device. It wraps a hypervisor-emulated GIC device (Vgic) provided by the
@@ -63,6 +64,21 @@ impl Gic {
         Ok(gic)
     }
 
+    pub fn restore_vgic(
+        &mut self,
+        state: Option<GicState>,
+        saved_vcpu_states: &Vec<CpuState>,
+    ) -> Result<()> {
+        self.set_gicr_typers(saved_vcpu_states);
+        self.vgic
+            .clone()
+            .unwrap()
+            .lock()
+            .unwrap()
+            .set_state(&state.unwrap())
+            .map_err(Error::RestoreGic)
+    }
+
     fn enable(&self) -> Result<()> {
         // Set irqfd for legacy interrupts
         self.interrupt_source_group
@@ -130,10 +146,9 @@ impl InterruptController for Gic {
     }
 }
 
-pub const GIC_V3_ITS_SNAPSHOT_ID: &str = "gic-v3-its";
 impl Snapshottable for Gic {
     fn id(&self) -> String {
-        GIC_V3_ITS_SNAPSHOT_ID.to_string()
+        GIC_SNAPSHOT_ID.to_string()
     }
 
     fn snapshot(&mut self) -> std::result::Result<Snapshot, MigratableError> {
@@ -141,17 +156,6 @@ impl Snapshottable for Gic {
         let state = vgic.lock().unwrap().state().unwrap();
         Snapshot::new_from_state(&self.id(), &state)
     }
-
-    fn restore(&mut self, snapshot: Snapshot) -> std::result::Result<(), MigratableError> {
-        let vgic = self.vgic.as_ref().unwrap().clone();
-        vgic.lock()
-            .unwrap()
-            .set_state(&snapshot.to_state(&self.id())?)
-            .map_err(|e| {
-                MigratableError::Restore(anyhow!("Could not restore GICv3ITS state {:?}", e))
-            })?;
-        Ok(())
-    }
 }
 
 impl Pausable for Gic {

devices/src/interrupt_controller.rs

@@ -24,8 +24,12 @@ pub enum Error {
     UpdateInterrupt(io::Error),
     /// Failed enabling the interrupt.
     EnableInterrupt(io::Error),
+    #[cfg(target_arch = "aarch64")]
     /// Failed creating GIC device.
     CreateGic(hypervisor::HypervisorVmError),
+    #[cfg(target_arch = "aarch64")]
+    /// Failed restoring GIC device.
+    RestoreGic(hypervisor::arch::aarch64::gic::Error),
 }
 
 type Result<T> = result::Result<T, Error>;