aarch64: Simplify GIC related structs definition

Combined the `GicDevice` struct in `arch` crate and the `Gic` struct in
`devices` crate.

After moving the KVM specific code for GIC in `arch`, a very thin wapper
layer `GicDevice` was left in `arch` crate. It is easy to combine it
with the `Gic` in `devices` crate.

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

devices/src/gic.rs

@@ -4,30 +4,34 @@
 
 use super::interrupt_controller::{Error, InterruptController};
 extern crate arch;
-use arch::aarch64::gic::GicDevice;
+use anyhow::anyhow;
+use arch::layout;
+use hypervisor::{arch::aarch64::gic::Vgic, CpuState};
 use std::result;
 use std::sync::{Arc, Mutex};
 use vm_device::interrupt::{
     InterruptIndex, InterruptManager, InterruptSourceConfig, InterruptSourceGroup,
     LegacyIrqSourceConfig, MsiIrqGroupConfig,
 };
+use vm_memory::Address;
+use vm_migration::{Migratable, MigratableError, Pausable, Snapshot, Snapshottable, Transportable};
 use vmm_sys_util::eventfd::EventFd;
 
 type Result<T> = result::Result<T, Error>;
 
-// Reserve 32 IRQs for legacy device.
-pub const IRQ_LEGACY_BASE: usize = arch::layout::IRQ_BASE as usize;
+// Reserve 32 IRQs for legacy devices.
+pub const IRQ_LEGACY_BASE: usize = layout::IRQ_BASE as usize;
 pub const IRQ_LEGACY_COUNT: usize = 32;
 
-// This Gic struct implements InterruptController to provide interrupt delivery service.
-// The Gic source files in arch/ folder maintain the Aarch64 specific Gic device.
-// The 2 Gic instances could be merged together.
-// Leave this refactoring to future. Two options may be considered:
-//   1. Move Gic*.rs from arch/ folder here.
-//   2. Move this file and ioapic.rs to arch/, as they are architecture specific.
+// Gic (Generic Interupt Controller) struct provides all the functionality of a
+// GIC device. It wraps a hypervisor-emulated GIC device (Vgic) provided by the
+// `hypervisor` crate.
+// Gic struct also implements InterruptController to provide interrupt delivery
+// service.
 pub struct Gic {
     interrupt_source_group: Arc<dyn InterruptSourceGroup>,
-    gic_device: Option<Arc<Mutex<GicDevice>>>,
+    // The hypervisor agnostic virtual GIC
+    vgic: Option<Arc<Mutex<dyn Vgic>>>,
 }
 
 impl Gic {
@@ -44,16 +48,32 @@ impl Gic {
 
         Ok(Gic {
             interrupt_source_group,
-            gic_device: None,
+            vgic: None,
         })
     }
 
-    pub fn set_gic_device(&mut self, gic_device: Arc<Mutex<GicDevice>>) {
-        self.gic_device = Some(gic_device);
+    pub fn create_vgic(
+        &mut self,
+        vm: &Arc<dyn hypervisor::Vm>,
+        vcpu_count: u64,
+    ) -> Result<Arc<Mutex<dyn Vgic>>> {
+        let vgic = vm
+            .create_vgic(
+                vcpu_count,
+                layout::GIC_V3_DIST_START.raw_value(),
+                layout::GIC_V3_DIST_SIZE,
+                layout::GIC_V3_REDIST_SIZE,
+                layout::GIC_V3_ITS_SIZE,
+                layout::IRQ_NUM,
+            )
+            .map_err(Error::CreateGic)?;
+        self.vgic = Some(vgic.clone());
+        Ok(vgic.clone())
     }
 
-    pub fn get_gic_device(&self) -> Option<&Arc<Mutex<GicDevice>>> {
-        self.gic_device.as_ref()
+    pub fn set_gicr_typers(&mut self, vcpu_states: &[CpuState]) {
+        let vgic = self.vgic.as_ref().unwrap().clone();
+        vgic.lock().unwrap().set_gicr_typers(vcpu_states);
     }
 }
 
@@ -97,3 +117,43 @@ impl InterruptController for Gic {
         self.interrupt_source_group.notifier(irq as InterruptIndex)
     }
 }
+
+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()
+    }
+
+    fn snapshot(&mut self) -> std::result::Result<Snapshot, MigratableError> {
+        let vgic = self.vgic.as_ref().unwrap().clone();
+        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 {
+    fn pause(&mut self) -> std::result::Result<(), MigratableError> {
+        // Flush tables to guest RAM
+        let vgic = self.vgic.as_ref().unwrap().clone();
+        vgic.lock().unwrap().save_data_tables().map_err(|e| {
+            MigratableError::Pause(anyhow!(
+                "Could not save GICv3ITS GIC pending tables {:?}",
+                e
+            ))
+        })?;
+        Ok(())
+    }
+}
+impl Transportable for Gic {}
+impl Migratable for Gic {}

devices/src/interrupt_controller.rs

@@ -24,6 +24,8 @@ pub enum Error {
     UpdateInterrupt(io::Error),
     /// Failed enabling the interrupt.
     EnableInterrupt(io::Error),
+    /// Failed creating GIC device.
+    CreateGic(hypervisor::HypervisorVmError),
 }
 
 type Result<T> = result::Result<T, Error>;