hypervisor: Define Vgic trait

Defined `Vgic` trait as the hypervisor agnostic interface for a virtual
GIC.

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

hypervisor/src/arch/aarch64/gic.rs

@@ -0,0 +1,64 @@
+// Copyright 2022 Arm Limited (or its affiliates). All rights reserved.
+
+use crate::{CpuState, Device, HypervisorDeviceError, HypervisorVmError};
+use std::any::Any;
+use std::result;
+use std::sync::Arc;
+
+/// Errors thrown while setting up the VGIC.
+#[derive(Debug)]
+pub enum Error {
+    /// Error while calling KVM ioctl for setting up the global interrupt controller.
+    CreateGic(HypervisorVmError),
+    /// Error while setting device attributes for the GIC.
+    SetDeviceAttribute(HypervisorDeviceError),
+    /// Error while getting device attributes for the GIC.
+    GetDeviceAttribute(HypervisorDeviceError),
+}
+pub type Result<T> = result::Result<T, Error>;
+
+/// Hypervisor agnostic interface for a virtualized GIC
+pub trait Vgic: Send {
+    /// Returns the hypervisor agnostic Device of the GIC device
+    fn device(&self) -> &Arc<dyn Device>;
+
+    /// Returns the hypervisor agnostic Device of the ITS device
+    fn its_device(&self) -> Option<&Arc<dyn Device>>;
+
+    /// Returns the fdt compatibility property of the device
+    fn fdt_compatibility(&self) -> &str;
+
+    /// Returns the maint_irq fdt property of the device
+    fn fdt_maint_irq(&self) -> u32;
+
+    /// Returns an array with GIC device properties
+    fn device_properties(&self) -> [u64; 4];
+
+    /// Returns the number of vCPUs this GIC handles
+    fn vcpu_count(&self) -> u64;
+
+    /// Returns whether the GIC device is MSI compatible or not
+    fn msi_compatible(&self) -> bool;
+
+    /// Returns the MSI compatibility property of the device
+    fn msi_compatibility(&self) -> &str;
+
+    /// Returns the MSI reg property of the device
+    fn msi_properties(&self) -> [u64; 2];
+
+    fn set_its_device(&mut self, its_device: Option<Arc<dyn Device>>);
+
+    /// Get the values of GICR_TYPER for each vCPU.
+    fn set_gicr_typers(&mut self, vcpu_states: &[CpuState]);
+
+    /// Downcast the trait object to its concrete type.
+    fn as_any_concrete_mut(&mut self) -> &mut dyn Any;
+
+    /*
+        /// Save the state of GICv3ITS.
+        fn state(&self, gicr_typers: &[u64]) -> Result<GicState>;
+
+        /// Restore the state of GICv3ITS.
+        fn set_state(&mut self, gicr_typers: &[u64], state: &GicState) -> Result<()>;
+    */
+}

hypervisor/src/arch/aarch64/mod.rs

@@ -0,0 +1,3 @@
+// Copyright 2022 Arm Limited (or its affiliates). All rights reserved.
+
+pub mod gic;

hypervisor/src/arch/mod.rs

@@ -10,9 +10,14 @@
 //
 // Copyright © 2020, Microsoft Corporation
 //
+// Copyright 2022 Arm Limited (or its affiliates). All rights reserved.
+//
 
 pub mod emulator;
 
 #[cfg(target_arch = "x86_64")]
 #[macro_use]
 pub mod x86;
+
+#[cfg(target_arch = "aarch64")]
+pub mod aarch64;